628,3 H872ex 1981 cop, 2 ECONOMIC IMPACT OF COMBINED SEWER OVERFLOW REGULATION [RULE 602] IN ILLINOIS DOCUMENT NO. 81/18 Printed by Authority of the State of Illinois UNIVERSITY OF ILLINOIS LIBRARY AT URBANA CHAMPAIGN BOOKSTACKG Doc. No. 81/18 April, 1981 ECONOMIC IMPACT OF COMBINED SEWER OVERFLOW REGULATION (RULE 602) IN ILLINOIS by Linda L. Huff Huff & Huff, Inc. CENTRAL CIRCULATION BOOKSTACKS The person charging this material is re- sponsible for its renewal or its return to the library from which it was borrowed on or before the Latest Date stamped below. You may be charged a minimum fee of $75.00 for each lost booic. Theft, mutilation, and underlining of books are reasons for disciplinary action and may result in dismissal from the University, TO RENEW CALL TELEPHONE CENTER, 333-8400 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN r;: uii When renevring by phone, write new due date below previous due date. NOTE This report has been reviewed by the Institute of Natural Resources and approved for publication. With the exception of the Opinion of the Institute's Economic Technical Advisory Committee, views expressed are those of the contractor and do not necessarily reflect the position of the IINR. Printed by Authority of the State of Illinois Date Printed: April, 1981 Quantity Printed: 600 Illinois Institute of Natural Resources 309 West Washington Street Chicago, IL 60606 (312) 793-3870 11 Opinion of the Economic Technical Advisory Committee of the Illinois Institute of Natural Resources The Economic Technical Advisory Committee has reviewed and approved an INR study entitled ECONOMIC IMPACT OF COMBINED SEWER OVERFLOW REGULATION (RULE 602) IN ILLINOIS. The study addresses an existing regulation prior to the enactment of Public Act 80-1218 (formerly P. A. 79-790) and as such constitutes the first economic impact study of a rule in existence before the October, 1975 adoption of the economic impact study legislation. In accordance with the provisions of P. A. 80-1218, the Committee has finalized its opinion and conclusion based on the information con- tained in the above-referenced study. By submitting its recommendation to the Illinois Pollution Control Board regarding Rule 602, an important facet of its statutory obligation is being fulfilled. Says the Act: "The Economic Technical Advisory Committee shall propose, for the economic study provided for in this amendatory Act, such rules and regulations of the Pollution Control Board in effect on the effective date of this amendatory Act as the Committee has reasonable cause to believe may, as applied, have an adverse economic impact, based upon the standards set forth in this subsection." The Act further states that: "The Institute shall publish its findings and conclusions with the supporting data used to reach said findings and conclusions, and the Institute shall file said economic studies with the Board." The opinion contained herein accompanied by the economic study fulfills the above-referenced mandate. According to Rule 602, first flush volumes receive secondary treat- ment and additional combined sewer overflows of not less than 10 times the average dry weather flow must receive a minimum primary treatment and disinfection with adequate retention time. This requirement is more iii stringent than that required by federal standards. Moreover, the funding status of the construction projects necessary to meet the re- quirement is questionable. Without federal funds, the affected muni- cipalities which number approximately 244 would be required to provide their own funds for such construction projects. In 1978, this capital 3 investment was estimated at $3,000,000,000 for Illinois. Such a financial demand imposes economic hardship on the municipalities. The study transmitted herewith investigates the economic and environmental consequences of meeting the existing regulation. The Committee finds that the cost of compliance for the municipali- ties relative to the environmental benefits which can be attributed to the existence of Rule 602 constitutes an unreasonable economic burden on the affected municipalities. As the study shows, the projected cost of compliance with Rule 602 is $476 million in capital expenditures and $72.5 million in annual operating costs. These costs represent conser- vative estimates as the "interceptor" costs were not included for 77 facilities. Complete elimination of Rule 602 would save $438 million 4 in capital funds and $67 million in annual operating costs. Of course, any evaluation of an existing rule must delineate the environmental and economic benefits which can be attributed to the existence of the regulation. Presumably, Rule 602 was established with the intent of protecting the water quality and environmental standards which would be negatively impacted in the absence of the regulation. As the study author notes, CSO occurs randomly, with differentia- tion in the degree and type of impacts. As a result, data does not exist to quantify precisely the impacts on the affected streams. Lacking such data, the report author utilizes pollution concentration in the IV overflow and annual loading contributions to estimate the impacts of Rule 602. Even with these techniques, quantifiable impacts that would delineate the resultant impact on streams is imprecise at best. The report author notes that "until site specific evaluations provide sufficient data, there exists no water quality information upon which to evaluate the importance of CSO control." The Committee notes t?iat the extent of water quality impact de- pends upon site specific characteristics; these are stream size, the volume of CSO and a plethora of other variables. But Rule 602 requires that all communities must meet the same treatment standards, regardless of stream size, water quality impacts or economic hardship. Inasmuch as water quality impacts are substantially influenced by the above-referenced variables, the study supports the conclusion reached by the Committee during the course of its deliberations. Namely, we find no economic justification for the continued existence of Rule 602, even with the caveats regarding the benefits of Rule 602 on water quality. As of this writing (April 15, 1981), the Committee notes that federal funding for all CSO projects under the new Reagan Administration will be eliminated. The President's new budget director, Mr. David Stockman, has stated openly that federal funding for CSO projects will be cut from the FY-82 budget of the federal budget. Under that circum- stance, the municipalities in Illinois would bear the t otal cost of con- struction of pollution control facilities necessary to meet Rule 602. Federal funding constitutes up to 75 percent of CSO funding. If the currently proposed budget cuts are realized, many municipalities could not bear the cost of compliance with Rule 602. The Committee finds that Rule 602 in its present form Imposes an unreasonable and undue economic hardship on the communities in Illinois V relative to the environmental benefits which can be assigned to Rule 602. We note that there is no evidence that Rule 602 is accomplishing the environmental benefits for which the rule was established. The final question becomes: Is the continuance of Rule 602 worth its economic cost relative to the environmental benefits derived from its existence? Based upon the evidence presented in the study, the Committee con- curs that there is no economic, environmental or other substantive evidence that would support the treatment requirement under Rule 602 in its present form. Therefore, the Committee recommends that the Pollution Control Board schedule public hearings as required by Illinois law for the purpose of considering the modification or termination of Rule 602. Says the Act: "Within a reasonable time but not longer than 120 days after each study has been filed with the Pollution Control Board and provided herein, the Pollution Control Board shall conduct public hearings throughout the State and to receive comments from the public regarding the study... The Pollution Control Board shall also speci- fically determine, whether as a result of their findings and conclusions, any regulations of the , Pollution Control Board shall be modified or eliminated." The Economic Technical Advisory Committee is pleased to note that this important statutory obligation is being fulfilled. ■'' S.H.A. , Chapter 96-1/2, Sub-Chapter 7404. ^ Ibid . ^ U.S. EPA Report No. 430/9-78-006, October ], 1978. Report to the Congress on Combined Sewer Overflow in the United States. The capital investment in Illinois for CSO was estimated at $3 billion, including the Tarp project. 4 S.H.A. vi TABLE OF CONTENTS List of Tables v List of Figures vii Executi ve Summary 1 Chapter 1 INTRODUCTION 21 2 BACKGROUND OF COMBINED SEWER OVERFLOW PROBLEM 25 2.1 Introduction 25 2.2 Characteristics of CSO Communities 26 2.3 Grant Status of Combined Sewer Communities 26 2.4 Treatment Requirements of Rule 602 Versus U.S. EPA Funding Criteria 32 2.5 CSO Characteristics of Affected Municipalities 34 3 EVALUATION OF COMBINED SEWER OVERFLOW CONTROL COSTS 37 3.1 Introduction 37 3.2 Combined Sewer Overflow Control Technologies 38 3.2.1 Combined Sewer Flushing 38 3.2.2 Existing System Management 40 3.2.3 Flow Reduction Techniques 41 3.2.4 Sewer Separation 41 3.2.5 Inline and Offline 42 3.2.6 Sedimentation 44 3.2.7 Disinfection 46 3.2.8 Cost-Effectiveness of Control Technologies 47 3.3 Costs of Alternative Levels of CSO Control 49 4 WATER QUALITY IMPACTS OF CSO 55 4.1 Introduction 55 4.2 CSO Pollutant Characteristics 55 4.3 CSO Water Quality Impacts in Illinois 62 4.4 CSO Pollutant Loading 68 4.5 CSO Controls and Associated Pollutant Reduction 72 vn TABLE OF CONTENTS (continued) Chapter Page 4.5.1 Rainfall Patterns 75 4.5.2 Estimating CSO Pollutant Reductions 78 4.5.3 Pollutant Reductions of Various CSO Level s of Control 88 4.6 Environmental Effects of CSO Controls 88 4.6.1 Removal of Organic Pollutants 88 4.6.2 Disinfection of Combined Sewer Overflows 93 4.6.2.1 Health Implications 93 4.6.2.2 Adverse Effects of Chlorination 100 4.7 Site Specific Examples 103 4.7.1 Description of the Site Characteristics of Casey 103 4.7.1.1 Planning Status of Community 105 4.7.1.2 CSO Loading Characteristics 105 4.7.1.3 CSO Control Cost 105 4.7.1.4 Water Quality Analysis 105 4.7.2 Description of Site Characteries of Charleston 106 4.7.2.1 Planning Status of Community 106 4.7.2.2 CSO Loading Characteristics 106 4.7.2.3 CSO Control Costs 107 4.7.2.4 Water Quality Analysis 107 4.7.3 Description of Site Characteristics of East St. Louis 109 4.7.3.1 Planning Status of Community 109 4.7.3.2 CSO Loading Characteristics 110 4.7.3.3 CSO Control Cost HO 4.7.3.4 Water Quality Analysis 114 4.7.4 Description of Site Characteristics of Georgetown 114 4.7.4.1 Planning Status of Community 116 4.7.4.2 CSO Loading Characteristics 116 4.7.4.3 CSO Control Cost 120 4.7.4.4 Water Quality Analysis 120 4.7.5 Description of Site Characteristics of Peoria .... 121 viii TABLE OF CONTENTS (continued) Chapter Page 5 BENEFIT/COST ANALYSIS 129 5. 1 Introduction 129 5.2 Control Costs Compared to Pollutant Reductions 129 5.3 Environmental Aspects of CSO Control 133 5.4 Summary of Cost-Effectiveness 138 5.5 Limitation to the Analysis 139 6 ECONOMIC IMPACTS OF RULE 602 143 6.1 Introduction 143 6.2 Capital Investment Impact Upon Local, State, and Federal Governments 143 6.3 Impact of Increased Operating Costs on Local Governments 144 6.4 Impact Upon the Agricultural Sector 149 6.5 Impact Upon Commercial and Manufacturing Sectors 149 6.6 Summary 150 References 151 Appendix 153 IX LIST OF TABLES Table Page 1 Summary of Incremental Cost Savings for Alternatives to Rul e 602 3 2 Concentrations of CSO, Sewage, and Stormwater *.'.*!.*'!.' .* 5 3 Comparison of Annual CSO Loadings to Treatment Plant Effluent Loadings 5 4 Receiving Stream Size as a Function of Discharger'site' ! 9 5 Categorization of Water Quality Impacts ][ 10 6 Cost Effectiveness of Various Treatment Schemes ........ 12 7 Range in Cost Effectiveness by Community .,,^ .' * 14 2-1 Population Statistics by County of Combined Sewer Municipalities 27 2-2 Community Size and Percent Combined Sewer in Affected Municipalities 30 2-3 Grant Status of Affected Municipalities 31 2-4 Summary of Priority Number of CSO Projects 32 2-5 Distribution of Percentage of Sewer Systems Combined 35 3-1 Combined Sewer Overflow Control Technologies 39 3-2 Costs of Sewer Separation for Illinois Municipalities 43 3-3 Range of Unit Costs and Pollutant Removal for CSO Control Technologies 48 3-4 Capital and Operating Costs of Compliance with Rule 602 51 3-5 Summary of Al ternati ve Costs 52 4-1 CSO Pollutants Affecting Water Uses 56 4-2 Quality Characteristics of First Flush and Extended Overflow 63 4-3 Categorization of Receiving Streams 64 4-4 Receiving Stream Size as a Function of Discharger Size 65 4-5 Categorization of Water Quality Impacts 67 4-6 Combined Sewer Annual Loading Equations 69 4-7 Comparison of Annual CSO Loadings to Treatment Plant Effluent Loadings 71 4-8 Rainfall Frequency-Intensity Pattern in Illinois 76 4-9 Mean Rainfall Characteristics of Illinois Communities 77 4-10 Typical Runoff Coefficients 81 4-11 First Flush and Primary Treatment Capacity as a Function of Rainfall 84 4-12 Pollutant Reduction Associated with Various Control Levels 89 4-13 Level of Protection for Alternative CSO Control Levels 91 LIST OF TABLES (continued) Table Page 4-14 Summary Information on Reported Waterborne Disease in the United States 94 4-15 Dose Response for Selected Enteric Microorganisms 95 4-16 Survival of Infectious Agents in Surface Waters 95 4-17 Reduction of Infectious Agents via Treatment Processes 93 4-18 Estimated Changes in Organisms Density with Treatment 99 4-19 Characteristics of Site Specific Examples 104 4-20 Summary of Water Quality Data for Cassell Creek 108 4-21 Control Costs for Rule 602 Compliance 115 4-22 Water Quality Samples Collected by lEPA in 1973, 1974, and 1978 122 4-23 Wet Weather Overflow at Regulators Along the Riverfront Interceptor - Peoria 123 4-24 Wet Weather Overflow Quality Information-Existing System/Existing Plant - Peoria 123 5-1 Total Pollutant Loadings and Annual Costs 130 5-2 Cost Effectiveness of Various Treatment Schemes 132 5-3 Environmental Implications of Alternative CSO Controls 135 6-1 Municipal Finance Characteristics by Population Size 146 6-2 Local Impact of Annual Costs of Implementing Rule 602 147 XI LIST OF FIGURES Figure Page 1 Distribution of Capital Costs by Community Size 16 1-1 Geographic Distribution of Population Served by Combi ned Sewer Systems 22 3-1 Cost of Storage Reservoir 45 4-1 Mortality of Juvenile Brook Trout Due to Low DO Level s 59 4-2 Time Scales for Storm Runoff Water Quality Problems 60 4-3 Space Scales for Storm Runoff Water Quality Problems 61 4-4 Typical Distribution of Stormwater Loadings 73 4-5 Frequency of Hourly Rainfall Events 75 4-6 Typical Distribution of Runoff Discharge (Hydrograph) 79 4-7 Typical Distribution of Maximum Pollutant Concentrations and Flow 83 4-8 Event of 2-22-79 14th and Gay Ill 4-9 Event of 2-22-79 East St. Louis Wastewater Treatment Plant 112 4-10 Event of 10-22-79 East St. Louis Wastewater Treatment Plant 113 4-11 General Location Map for Monitoring Program - Georgetown, Illinois 117 4-12 3/21/79 - BOD. Flux for Georgetown 118 4-13 3/21/79 - Suspended Solids Flux 119 6-1 Distribution of Capital Costs by Community Size 145 xn EXECUTIVE SUMMARY Combined sewer overflows (CSO) are a source of pollution which is expensive to control and difficult to quantify. Designed to carry storm water and sanitary waste, combined sewer systems in Illinois may contain between 1 and 45 overflow points for excess flows during storm events. The quantity of pollutants discharged is a function of the accumulated solids, storm intensity and duration, and the hydraulics capacity of the sewer system. In Illinois Rule 602 specifies the level of treatment required for combined sewer overflows. The content of this rule is as follows: a) All first flush as determined by lEPA must receive secondary treatment. b) Additional flows, not less than 10 times the dry weather flow shall receive primary treatment and disinfection. The need for CSO treatment has been identified for 132 municipalities outside the TARP (Tunnel and Reservoir Plan) area of Cook County. These municipalities serve 1.2 million people or 22% of the population outside Cook County. The communities range in size from a few hundred people up to populations of 83,000. These communities are scattered throughout the state. The sewer system of the community may have as little as 10% or as much as 100% combined. Approximately half of the affected towns have systems which are 100% combined sewers. Evaluation of Regulatory Alternatives Control of CSO typically requires either collection and transport of overflows to the treatment plant or sewer separation. Each method is costly and does not result in a 100% elimination of the pollutant loading. To evaluate the cost-effectiveness of Rule 602, seven alternatives are considered according to costs and environmental effects. The following alternatives provide a range of treatment requirements and discharger categories for analysis: a) Primary treatment of five times dry weather flow, first flush treatment, and chlorination. b) Primary treatment of two times dry weather flow, first flush treatment and chlorination. c) Rule 602 without disinfection. d) Exemption of municipalities on major streams. e) Exemption of municipalities serving a combined sewer population of less than 3000. f) Use of management practices (sewer flushing) for towns with priority numbers above 806. (Only Step 1 funding is available for this group.) g) Elimination of Rule 602. Control Cost Savings The projected costs of Rule 602 compliance are $476 million in capital expenditures and annual costs of $72.5 million. These costs represent conservative estimates since interceptor costs were not included for 77 facilities. Forty percent of the capital costs are sewer separa- tion projects and the remainder are store and treat projects. Only $30 million of $476 million has been funded for these CSO projects. This means over $400 million is needed to resolve the problem. Table 1 presents the incremental cost savings associated with . alternatives to Rule 602. These alternatives were analyzed to provide some measure of the potential benefits of modifying Rule 602. A reduc- tion in the primary treatment requirement decreases the capital costs by 50 to 70%. If particular discharger groups were exempted from the regulation, the total savings are smaller. The 37 communities with under 3000 population served by combined sewers represent 10 and 15% Table 1 SUMMARY OF INCREMENTAL COST SAVINGS FOR ALTERNATIVES TO RULE 602 Regulatory Alternative Capital Cost Annual Co^t Savings! Savings,' $ million $ million/yr Primary treatment of 5 x flow 230 20.6 plus first flush plus chlorination Primary treatment of 2 x flow 315 36.5 plus first flush plus chlorination Rule 602 without disinfection 12 3.3 Exemption of municipalities on 135 15.5 major streams Exemption of municipalities 50 4.3 of combined sewer populations less than 3000 Use of management practices for 78 11 towns unlikely to obtain funding (priority no. >806) Eliminate Rule 602 438 67 Notes: 1) Cost savings are calculated on difference between $376 million for Rule 602 and the alternative, 2) Annual savings are difference between $72.5 million of Rule 602 and the alternative. of the capital and operating costs, respectively. The 27 towns on major streams can save $135 million or 28% of the total regulatory capital cost. Complete elimination of Rule 602 would save $438 million in capital funds and $67 million in annual costs. The remaining funds have already been committed for CSO projects. Environmental Costs of CSO Any modification of Rule 602 which is considered must evaluate not only the benefits but also the environmental costs. Because CSO is an intermittent phenomenon with varying degrees of impacts, few attempts have been made to quantify its contributions to receiving streams. The discharge of organic material, nutrients, and sediment have detrimental effects upon the receiving stream. These effects are typically monitored only immediately downstream, if at all. The deposited organic materials which are first flushed out of the sewer system have concentrations greater than that of raw sewage and result in the greatest impact. These materials demand oxygen for degradation and may accumulate as sludge banks downstream. Depending upon the stream size and quantity of first flush, water quality conditions can deteriorate for days after rainstorm events. The impact of CSO can only be described via two general procedures; one is pollutant concentration in the overflow and the other is a compar- ison of annual loading contributions. Table 2 summarizes the typical concentration ranges of CSO, raw sewage, and urban storm water. Organic and suspended solids concentrations in first flush are greater than in raw sewage; however, storm water concentrations from separate storm sewer discharges of suspended solids typically exceed CSO values. Thus, the probable water quality impact of stormwater cannot be ignored as a factor as well . The annual loading attributed to CSO has been calculated for 63 of the 132 communities, and Table 3 compares these contributions to the wastewater treatment plant effluent loading. Table 2 CONCENTRATIONS OF CSO, SEWAGE, AND STORMWATER Water Source Typical Concentration of Pollutants, mq/l BODg Suspended Solids Total Nitrogen CSO, first flush^ 186±40 522+150 17.6±3.1 CSO, extended flow^ 49±10 166±26 5.5±0.8 Typical Raw Sewage^ 200±10 200±100 40 Stormwater^ 30±170 630±2000 3 Reference 13 2 Values averaged from Lager, J. and Smith, W. "Urban Stormwater Management and Technology," EPA 670/2-74-040, December, 1974. CO Q o LU I— ct _J Q. h- UJ > i*^ I/) »4- jQ UJ r— Q. „ I— J/) IS. -o :s •1— ^— o t/1 -o O) -o c O) Ql 00 r^ oo o 00 , — o fO 3 C o o o o o CD O o C\J U3 o o o o IT) o o o o o V£> CM O o o M o o o < o o 4-> C i- OJ fO 3 cu n— >, «+- ^- to UJ X3 Q. f— «\ 3 Ol 3: c •r— "O fO O _l un C3 o CO 1 O (O oo rj o c c cC I o o O o O o o o o o o to <^ 1 — I oo o o o o o o o o o o o o o o o o CD O CD O o o o o o o o o o o o o o o o o o o o o OD 00 LT) O en o r^ ^ ^ en LO CVJ o o o o o CO <:^ C\J o o o o o o o •I o 00 o CNJ o o o o o oo oo oo o o o o o o o o o o o o CD O O O o o oo oo f^OO 00 kD t— I LD o o CO r~^ 00 UD o o o o CD O o o CO VD UD O CO I ft3 O r— O 13 O CLcn o Q. c: 4- .C o +-> I/) cu CO +-> to -r- cz • — Z5 fO E 4-) E o o I— o 1/1 CO •r- O) +-> r— LO OJ S- OJ 00 -o OJ o o >> JD c oo CO -o E 4-> O) 03 S_ o +-> O 00 oo C OJ cu •r- -(-> 4-> ■\-> ■o OJ 4-> o OT3 1 — 00 E oo ra cu (U •r- S- •r- -I— oo CZ C TD :3 o cu E •■- > E -t-> s- O rO cu CD I — to C E =3 S- E -r- o O 03 <_) E o o o o o 00 in o o o o o o CD CD o o CNJ •■- CD S- CO o •r- C Q-jC +-> 4-> S- •r- OJ to cu cu s- •r- CTl +-> •I— oo C i- Z3 cu E -o E E o rj CD C cu E 4-J fT3 (U s_ +-) o c -o t: "o -o cu cu cu (U •I — •! — •( — -r™ t|_ 4_ t|_ 4_ +J +J 4_) ^_) c c: c: c cu (U cu cu -o -o -o "O to 00 to to cu cu cu cu 4-) 4-) -M -|-> c: c :3 ^ E E E E o o o o CvJ <:J- 4- 4- o o ^ LD r^ en CO ^r o cu E 13 oo oo 00 CO <— • 00 -M C71 c: £= cu •I— 00 cu S- cu o C/5 oo c_> cu cu <— -cr 03 o: JD O "O cu TD 03 o 4-> -l-J 4-> c c c cu cu cu oo 00 oo cu cu cu S- S- S- Q. Q. Q. CU CU CU S- S- s- (/) to oo cu cu cu cu ^-> o The annual BODc loading attributed to untreated CSO is comparable to that of the wastewater plants. The annual suspended solids contri- bution of untreated CSO is 7 to 13 times greater than that discharged from the wastewater treatment plants. This proportion is considered representative of the overflow contribution for all 132 plants. The BODc and suspended solids associated with small combined sewer areas, communities on intermittent streams, and communities discharging to major tributaries are also of concern. The magnitude of CSO con- tributions is summarized in Table 3 for these three groups. The small communities represented 5% of the total CSO contribution by 63 communi- ties. The BODc loadings of CSO are comparable to the wastewater treatment plant discharge, and the CSO suspended solids loading ranges from 11 to 22 times larger than WWTP effluents. Table 3 also presents the pollutant loading contributions of com- munities located upon major streams (whose low flow exceeds 400 cfs). The CSO and WWTP loadings for BOD^ are comparable and represent 39% of the statewide BOD^ loading from CSO. Suspended solids attributed to CSO exceed the WWTP loading by 4 to 10 times for this discharger grouping. If the pollutant loadings calculated for the 63 communities are considered representative, then the untreated combined sewer overflows of the 132 affected dischargers contribute as much as the wastewater treatment plants. Suspended solids attributed to CSO far exceed those loadings discharged from treatment facilities. Thus, though the over- flows are intermittent in nature, individual events contribute as much as or more than treatment plant discharges. CSO and WWTP loadings are not the only factors affecting water quality. Non-point sources, such as agricultural runoff and urban stormwater, also affect water quality. To indicate the relative magnitude of urban stormwater versus combined sewer loadings, the equations generated through U.S. EPA studies can be compared. Stormwater BODj. and suspended solids loadings are typically 0.25 of CSO values. The extent of the water quality impact depends upon site specific characteristics, such as receiving stream size, quantity of CSO, magni- tude of rainfall event, and many other variables. Table 4 presents a categorization of dischargers by effluent flow and stream flow. Approximately 50% of the affected dischargers are located on inter- mittent streams, and the remainder are divided between intermediate and major receiving streams. Although these categories are defined according to low flows, the ability of the stream to assimilate untreated discharges is a function of size. The six combined sewer communities of over 50,000 population are all located on intermediate or major streams in Illinois. With a wide range in stream and town sizes, it is not surprising that water quality impacts occur in each stream category. The water quality effects of CSO have been described in general terms because there is so little information available regarding specific impacts in Illinois. The Illinois Environmental Protection Agency (lEPA) has qualitatively described CSO water quality problems for 54 of the 132 dischargers. Table 5 summarizes the extent of data available from this qualitative assessment. In a review of facility plans, site inspec- tions, and other lEPA data, the water quality impact of CSO downstream was not quantitatively measured for any community outside the planning areas of NIPC (Northeastern Illinois Planning Commission) and SWIMPC (Southwestern Illinois Metropolitan Planning Commission). Five site specific examples of CSO communities were investigated for the level of available water quality data. In each case there may have been monitoring of the overflow during the storm event; however, the greatest distance monitored downstream was one mile and this was analyzed only during the storm. If, indeed, CSO impacts extend for days, there has been no attempt to collect such data for communities who will soon be spending millions of dollars. Part of the problem in quantifying CSO effects is the cost and magnitude of a water quality monitoring program. A series of recording stations up to 40 miles or more downstream would need to be established O) J3 03 »— < oo a: LU q; <: =n o oo o I— I — I oo s: «=c LxJ Qi t— OO CO UJ O) N oo en o o u_ CD +-> CO E ra O) OO cn c: o OJ OJ -Q E 13 N OO o CO M- O E nD O OJ O S- ^ 4-> OO A S- s o o •<—> ( — ■ rrs <+- 03 a> %. +-> oo QJ +-> 03 "O OJ E S- OJ +-> c a cr> en m I o cu i- ■!-> OO +-> O) -M +-> E O) +J c CO CO 00 uo oo CO CO oo oo CTt KSD <\i OJ OC3CDOCDOOCD 00C500000 0000C3000 #» »v #^ #v f\ *\ r» n ,— 1 LD o uo o o o o o o ■ — 1 1 — 1 oo CO '=r uo U3 o o 1 1 1 1 , 1 1 , o o UD o o r-l I— 1 1 — 1 . — 1 . — 1 1 — 1 1—1 " o o o o o o o o A . — 1 o o o o o o o o V 1 — I tn o LO o o o o . — 1 r-( oo oo ^ LO 10 OO 1— ■3: cr in Qi LU o) ca: r- 3 jQ m u_ I — I or o o LU I— in (_> o o Li_ M- O (/) o +-> O CT^ t/) I/) Q I/) o (/) CO I/) I/) (T3 O LO 4-> (_) n3 Q. E 4-> ro OD CO ro c\j CNj n ro 00 CM CO LT) C\J CO UD C\J 00 UD c o 03 c CO n3 o -o c 4-> ■r— •r- cu c 4-) 1 — CJ1 o fO o >> o -o CO X fO o 1 — S- XJ fO CD cu X) o O) -o (U •1 — Q c > en O) r o o Q. o ■r— 00 CO o •4-) =3 CO • 1 — cu CO •r- S- sz "O cu +-> -E +J to CD 3 o cu -1 — o n3 ■=c zc 1 CQ cu S- oo TJ +-> Q. •r— Q. I/) 03 o Q. CO -o O a» cu u- en <+- ■o O) Z3 CO • E CO fO E O) fO S- O) ■ +J i- CO CO 4-> E I/) fC 1- QJ O • J- i_ •'-5 1/1 o +-> ro E '--> CO E fO fO OJ E +-> -a s- c c +-> i- OJ ro CO o +J -t-> OJ +J OJ •r- 4-J C +J E n3 CU fO S- -r- +J •r— cu "O +-> -o 4-> 4-> +-» o c: c c •r— '1 — •r— -a cu c= c c +-> o o o fO u -o -o -o o cu (U +J +-> fO fO (O "O o u o coo o fO r- r— ' — o o o o o o o o o o o o ^ 9* n #^ • LO un o o o CO CM O c c o fO fO o o -> -C -C 4-> +-> o 4-> +J C\J U. OO o c/1 CO O O S- co I/) CZ) O CU O) cu »- .> > 1 — 1 — en un o cr c c c c o o o o o +-) +J 4-> -M 4-> ro 1^ fO fO f^ Z3 13 13 13 ZJ Q. CZL CL CD. CX O O O O O CL Q. Q. Q. C3l 1+- 4- <+- <+- *+- O O O O O CO CO (/) CO to c c c c c 2 3 5 2 5 O O O O O I I I I I cC CQ C_) CI UJ CO to to to to to to to to 1/1 (T3 ro ro fO fO C_) C_) (_) CJ t_> 11 for a six to twelve month period. The influence of non-point contribu- tions, such as urban stormwater and agricultural land runoff, would also have to be factored out of the results. Such a program would probably delay projects a minimum of two years. Rule 602 was designed to protect streams via stringent treatment requirements. To assess the need for Rule 602 or some less stringent regulation based upon stream degradation, additional water quality data are needed. Until site specific evaluations provide sufficient data, there exists no water quality information upon which to evaluate the importance of CSO control locally, regionally, or statewide. The decision criteria presently advocated by U.S. EPA policies is one considering the cost-effectiveness of control strategies. The U.S. EPA requires an analysis which evaluates increasing levels of pollu- tant reduction according to the cost per pound of pollutant removed. Also, the pollution control project must be compared to other alternative projects. In the case of CSO, the comparable cost of tertiary treatment is evaluated. To depict the efficiency of each alternative treatment process, the cost of removal per pound of pollutant is presented in Table 6. These values represent incremental removals of each process. Clearly, first flush treatment is the most cost-effective portion of Rule 602. The economies of scale are evident as the capacity of a primary treatment process decreases from ten to two times dry weather flow. Unit costs simultaneously increase from $7.40 to $12.00 per pound of pollutant removed. There is a cost differential in treatment efficiency between small and large communities. The average removal charge for towns of less than 3000 is $2.40 per pound of pollutant removed,* while towns on large streams incur removal costs of $1.00 per pound. Best management prac- tices (sewer flushing) have costs equivalent to or lower than first flush removal . *BODr plus suspended solids 12 Table 6 COST EFFECTIVENESS OF VARIOUS TREATMENT SCHEMES Treatment Scheme $/(Pound BOD Plus TSS Removed)^ Rule 602^ - Aggregate 1.70 - Towns <3000 PE 2.40 First flush treatment^ 0.94 Primary treatment lOx dry weather flow 7.40 Primary treatment 5x dry weather flow 7.90 Primary treatment 2x dry weather flow 3.30/12.00 Best management practices 0.36/0.97 Dischargers to major streams 1.00 f Typical sewage treatment plant costs 0.55 Notes: a) January 1980 cost basis, includes annualized capital cost. b) Includes both first flush treatment at 2.5 times dry weather flow plus primary treatment at 10 times the dry weather flow and disinfection. c) First flush treatment for 2.5 times dry weather flow includes pumping. d) Costs based on sedimentation plus pumping for all except 2x D.W.F. First value is without additional pumping costs. e) Combined sewer flushing based on 15% to 40% removal. f) For 1 MGD plant, assumed capital cost of $4.6 M and operating cost of $257/million gal., all assigned to BODr and SS removal. 13 According to estimates of removal efficiencies, the incremental BODc and suspended solids reduction attributed to primary treatment is less than 4% of the total CSO contributions and 70% of the cost. Thus, the primary treatment requirement provides little environmental protection for the associated cost on a general basis. Economic Impacts The economic considerations of implementing Rule 602 or other alter- natives pertain mainly to the generation of capital and operating funds by the affected municipalities. The capital costs of combined sewer over- flow treatment may be funded up to 75 percent by the state and/or federal government. Local governments would be expected to generate the 25 percent of the capital investment as well as the operating and maintenance cost of control facilities. Those communities whose priority number is greater than 806 are presently eligible for only Step 1 or planning funds. Con- struction funds may eventually (5 years or more) become available but there is no certainty of that funding. For 33 communities with preliminary engineering reports, the cost per pound of BOD^ and SS was calculated to indicate the range in cost- effectiveness. Table 7 results indicate that some communities would be required to pay higher costs for Rule 602. Thus, the cost effectiveness of Rule 602 significantly varies for each community. Although the state- wide removal cost of Rule 602 is $1.70 per pound pollutant removed, there are communities which would be paying far greater costs for lower removals. Such conditions are associated with site specific factors of the community. This variation in cost per pound removed is far greater than that associated with secondary or tertiary treatment processes. 14 Table 7 RANGE IN COST EFFECTIVENESS BY COMMUNITY Rule 602 Removal Cost, ... ^ ^ $ per pound BOD^ + SS ^'"^^^" °^ Communities LT 1 4 1-2 4 2- 4 10 4-6 3 6-8 4 8-10 3 10-12 2 12-14 14-16 2 GT 16 _1 33 15 a) Capital Investment Impact Upon Local, State and Federal Governments The implementation of Rule 602 is estimated to require $476 million for those communities outside the TARP (Tunnel and Reservoir Plan) area. This implies the local government share is $119 million and state/federal funding will produce the remaining $357 million. The total capital invest- ment for projects with a priority number greater than 806 is $147 million or 31 percent of the total CSO funds required. The ability of the commun- ities to obtain any state or federal funding for these projects is ques- tionable. The impact of generating 25 to 100 percent of the capital invest- ment for CSO varies from community to community depending upon the size of the community and magnitude of funds required. Figure 1 depicts the local capital cost burden according to town size, assuming all projects receive 75 percent state/federal funding. The smaller municipalities (population less than 2500) must generate on average $50,000 to $100,000 and some as high as $300,000 for capital investment. Cities of 2500 to 10,000 population averaged a capital investment of $200,000 to $300,000; and those cities of population greater than 10,000 incurred an average capital cost of $500,000 to $1,000,000. These costs, of course, represent only one-fourth of the total control cost. The average level of indebtedness associated with CSO control imposed upon communities varies from $20 to $40 per capita; however, individual sites may incur higher costs. This level of increased debt can be compared to typical municipal outlays and revenue. Total annual capital outlays range from $20 to $81 per capita, depending upon town sizes. Thus, the local share of CSO control represents a minimum of one year's total capital budget and for many this capital outlay for CSO would absorb all capital investment for several years. 16 •-> o o o o o o o 4..0 o o o o CM r— ( O O o o o o • o o o o f2 r^ O O O o o o o -o o o o 1 — I LO >- ^ o *» r) o o QJ s: o o S- 2: »s 9S (T3 ■■- o o JZ c_) o o oo tn o >- ^ -M ca f— 1 (/) O i/> o 1— 1 1 — 1 (>0 .- o t— o o fT3 j o o -(-) O) #* #» •1 — S- _j ^ o o Q. 3 ct o o — 1 CM -t- 00 i f .--< ... 1 1 (- ■ — H kO '^ CM CO ^o ■* o o o o o o o o un o o CD CD o LD V sjaBjpqDSLQ j.o # 17 b) Impact of Increased Operating Costs on Local Governments The incrrease in annual costs of wastewater treatment due to CSO con- trol varies with magnitude of the CSO problem and town size. The annual cost includes operating and maintenance expenses in addition to 25 percent of the total amortized capital charges. These increased costs represent additional taxes or loss of services to tne residents of impacted municipalities. For 55 municipalities or 47 percent the increase in annual costs is less than $20.00 per person or $80.00 per household. The annual costs rise to $20.00 to $40.00 per person for an additional 39 communities or 33 percent of the total towns evaluated. The remaining 20 percent of the impacted communities would incur increased costs between $41.00 and $300.00 per person for CSO control. The communities affected by these high costs range in size from 1,000 to 74,200 popu- lation. The annual costs of CSO control can be compared to the general revenue of various town sizes. Over 50 percent of the affected municipalities would incur additional costs greater than $20 per capita, which represents 5 to 13 percent of the total revenue generated. This is the minimum incremental expense. A far greater increase is anticipated for at least one-third of the communities. For at least 16 small towns (population less than 5000), annual budget increases exceeding 20 percent would be expected. Such a large increase could only be sustained by an increased tax burden or reduced services. Therefore, there appears to be significant economic impacts upon combined sewer communities. c) Impact Upon the Agricultural Sector No direct costs 3re anticipated for the agricultural sector as a result of Rule 602 implementation. 18 d) Impact Upon Commercial and Manufacturing Sectors Commercial and manufacturing facilities located in combined sewer or flood prone areas may incur costs for storm water control. Onsite detention or retention of stormwater may be stipulated by communities to reduce the immediate volume impact during a storm event. In Peoria, Springfield, Decatur, and Kankakee onsite detention is not practiced effectively but the sanitary district or community does have the capa- bility to stipulate such actions. There is no estimate available of capital costs incurred by industry for stormwater control due solely to combined sewer conditions. Such costs, however, should be considered as a potential impact of combined sewer control. Funds required for combined sewer control represent an alternative use of pollution control expenditures for some communities. A reduction in funds required for CSO could result in either the resolution of other pollution problems or a savings in governmental operation. Recommendations Rule 602 in its present form provides a level of environmental protection, which varies from municipality to municipality. The economic impacts of implementing such criteria are severe for approximately 20% of the municipalities, and the capital and annual costs represent a large demand on available pollution control funds. A review and modification of Rule 602 to correlate with desired stream uses and water quality goals seems appropriate. Although data regarding wet weather water quality are limited, it is apparent that combined sewer overflows can be important contributors of pollutants. The general impact of CSO varies with receiving stream size and pollu- tant discharge. The concept of completely treating all CSO is not cost- effective and impractical due to funding constraints. 19 Rule 602 is inflexible in that all communities must provide the same level of treatment regardless of stream size, non-point source contributions, water quality impacts, or economic hardship. Rule 404 specifies various effluent levels of BODj. and suspended solids for dis- chargers depending upon stream size. Some of the alternatives to Rule 602 considered size factors. The analysis of dischargers on large streams and small communities indicated such simple groupings were not sufficient; however, some consideration of the factors previously cited is important. Since water quality impacts vary according to stream size and discharger size, the treatment requirements of combined sewer over- flows should perhaps follow the example of Rule 404. An analysis of several alternative regulations indicates that no general rule can readily replace Rule 602 without the same problems of uncertain economic hardship and water quality impact. A case-by-case evaluation of CSO should be implemented with an lEPA technical policy similar to that of the U.S. EPA for analyzing costs and water quality concerns. CSO loadings should be evaluated as one factor affecting stream water quality, and there must be some effort to relate other factors to the water quality goal. Recognizing the limited resources available for pollution control, it is important that funding be appropriated for the most cost-effective projects with greatest water quality benefits. Rule 602 in its present form constrains the achievement of water quality in the most efficient manner. A case- by-case analysis provides the only mechanism for CSO control in a cost- effective manner with the necessary improvement in water quality. 21 EVALUATION OF THE ECONOMIC IMPACT OF COMBINED SEWER OVERFLOW REGULATION IN ILLINOIS 1. INTRODUCTION Combined sewer overflows (CSO) are a source of pollution which is expensive to control and difficult to quantify. Combined sewers are those sewers which carry both sanitary sewage and stormwater through the same sewer to the treatment plant. During storm events the sewer system may become overloaded resulting in overflow of untreated sewage into the streams or backup into basements or streets. Combined sewer overflows have been recognized as a national problem; however, the Midwestern states including Illinois represent a major problem. These states have over 50 percent of their population served by combined sewers. Figure 1 illustrates the severity of the problem for each state. In formulating water pollution regulations, the Illinois Pollution Control Board adopted Rule 602 which pertained to treatment of combined sewer systems. According to Rule 602(c) treatment of CSO must meet the following criteria: 602(c): All combined sewer overflows and treatment plant bypasses shall be given sufficient treatment to prevent pollution or the violation of applicable water quality standards. Sufficient treatment shall consist of the following: (1) All dry weather flows, and the first flush of storm flows as determined by the Agency, shall meet the applicable effluent standards; (2) Additional flows, as determined by the Agency but not less than ten times the average dry weather flow for the design year, shall receive a minimum of primary treatment and disinfection with adequate retention time; (3) To the extent necessary to prevent accumulations of sludge deposits or depression of oxygen levels, flows 22 E > CO SOURCE: CH M HHI, 1978 Needs Survey Cost Methodology for Control of Combined Sewer Overflows and Storm Water Discharges , U.S. EPA, 430/9-79-003, February, 1979 23 in excess of those described under paragraph (c) (2) above shall be treated by retention and return to the treatment works or otherwise. When the Agency finds it necessary, part or all of such excess flows shall be treated to substantially remove floating debris and solids. 1 This policy was to be implemented by December 31, 1975 for all combined sewer overflows except the Metropolitan Sanitary District of Greater Chicago which had until December 31, 1977. The Illinois Environmental Protection Agency (lEPA) proposed a modification (R75-15) in compliance date due to funding constraints and the ensuing IPCB opinion provided relief to communities as long as they had made application for grant funding by December 31, 1975. This IPCB action was considered sufficient to reduce any economic hardship. Since the granting of the variance, several factors have emerged which will affect the treatment of CSO and the related economic impact upon combined sewered municipalities. The U.S. Environmental Protection Agency has issued program guidance memorandum (PG-61) for ascertaining 2 the availability of federal grant money. This guidance relates treatment of combined sewer overflows to the cost-effectiveness of alternative levels of control. Thus, the federal government analysis may result in funding a lower level of treatment than that required by Rule 602 (c) (1) and 602 (c) (2). Also, the federal government will only fund the pollution control portion of CSO even if flooding and basement backups are of concern in treating such overflows. Another dimension to the problem of controlling CSO is that analysis recently published by GAO evaluating the 1 ikel ihood of funding for combined sewered municipalities. The nationwide needs of $26 billion are so high that funding is considered years away if ever. Also, municipalities receive funding from state and federal sources for capital intensive projects while other alternatives considered "best management practices" (BMP) are operating expenses incurred solely by municipalities. This has resulted in the limited use of BMP. The best management practices (BMP) do not result in the same level of pollution and flood control 3 as capital-intensive solutions; however, the costs are much lower. 24 This study focuses upon the status of CSO control in Illinois and the problems of compliance with the existing regulations (Rule 602). Alternative levels of regulation are considered and the resulting costs and environmental benefits are presented. Funding of such CSO projects is important in determining the economic impact upon municipalities. The conflict between state and federal requirements as well as the general availability of funds for CSO control indicates that the municipalities may face economic burdens. The area designated as the TARP (Tunnel and Reservoir Plan) area, which includes Chicago and 55 suburbs of Cook County, is not included in this evaluation. The area characteristics, economics, and environmental effects of TARP are unique and have been well described previously. Therefore, this study focuses upon all combined sewer systems outside of TARP. Data collected in this study came from different sources, such as lEPA files, studies submitted by municipalities, conversations with consulting engineers, and federal baseline information. There were frequent conflicts in data, and the general background presented in Section 2 represents the most complete and accurate description available. 25 2. BACKGROUND OF COMBINED SEWER OVERFLOW PROBLEM 2. 1 Introduction Combined sewers serve over fifty percent of the people living in Illinois. These combined systems of storm water and sanitary waste not only contribute to pollution problems but also flooding and basement backups during wet weather. Originally designed to handle both storm and sanitary wastes, the combined systems due to deterioration have reduced capacities. Overflow points were included to transmit excess flows directly to the stream without treatment, and towns may have from 1 to 30 overflow points in the system. With reduced carrying capacity, the CSO becomes a pollution problem because of discharge frequency and the impact of raw sewage and storm water upon the receiving stream. To reduce the pollution requires either new sewers or storage and treat- ment of overflows. Both are costly solutions. Identification of municipalities containing combined sewers is often difficult since only a portion of the town may be combined. Those towns started in the period of 1850 to 1900 may have central areas served by combined sewers while more recent developments have separate sewers. 4 The 1978 U.S. Environmental Protection Agency Needs Survey identified 118 communities with combined sewers excluding Cook County. The Illinois Environmental Protection Agency (lEPA) lists 91 municipalities outside Cook County and 51 within Cook County with combined sewers. An earlier 5 economic impact report categorized 279 projects on the funding priority list. (This included Cook County projects and towns.) By reviewing lEPA files, contacting consulting engineers, and referring to source descriptions, a list of 132 municipalities outside the MSDGC planning area was compiled. This list represents the best estimate of municipalities requiring or presently constructing combined sewer overflow treatment. The statewide impact of combined sewer regulation is described in terms of these affected communities. In this section background information is presented for these 132 municipalities. The location, population, CSO characteristics. 26 and funding status of these affected communities are presented herein. 2.2 Characteristics of CSO Communities The 132 combined sewered municipalities are located throughout the state, and Table 2-1 summarizes their location according to county. These communities appear in 61 of the 102 counties in Illinois and serve l.k^ million or 22 percent of the population outside the MSDGC area. The populations served by the combined sewer areas \/dry from a few hundred up to town sizes of 83,000 people. Table 2-2 summarizes the size distribution of towns containing combined sewers. The communi- ties of less than 10,000 people represent 62 percent of the total number affected. These smaller communities have a more difficult time generating funds for capital improvements and are considered sensitive to economic hardships. 2.3 Grant Status of Combined Sewer Communities To assess the magnitude of the problem the grant status of the CSO communities was reviewed. This status in the grant program indicates the progress made in evaluating the CSO problem and funding a treatment program for CSO. The lEPA and U.S. EPA construction grants programs utilize a three-phase development program categorized as follows: Step 1 - Planning of Facilities and Evaluation of Alternatives Step 2 - Design and Specifications of Project Step 3 - Construction of Facilities Frequently combined sewer treatment projects are evaluated at the same time as treatment plant expansions or improvements. However, funding may occur separately. Therefore, it may be difficult to segregate the progress of CSO treatment for multi-purpose projects. Table 2-3 summarizes tho present grant status of the 132 affected municipalities. This summary is obtained from Exhibit 1 in the Appendix. Ninety-eight of the 132 municipalities have completed or are progressing on Step 1 studies while 29 of these have progressed through to Step 3. 27 Table 2-1 POPULATION STATISTICS BY COUNTY OF COMBINED SEWER MUNICIPALITIES County Adams Alexander Bureau Carroll Cass Christian Clark Coles Cumberland DeKalb DeWitt DuPage Edgar Effingham Fayette Ford Fulton Greene Grundy Hancock Hardin Iroquois Jefferson Jersey Jo Davies Kane Kankakee Total Number of CSO Towns Total Population Served by Combined Sewers 1 50,288 1 6,500 5 8,425 1 1,500 1 6,700 4 32,882 3 ^ 1,800 2 29,500 1 1,100 1 7,800 2 8,815 4 62,000 2 10,850 1 1,000 2 11,700 2 2,000 1 15,000 1 3,000 1 9,000 1 3,400 1 1,400 3 2,121 1 20,000 1 7,400 1 3,900 3 105,360 5 33,576 28 County Table 2-1 (cont'd.) Total Number of CSO Towns Total by Pop Comb ulation Served ined Sewers 1 1,000 2 32,900 2 1,320 7 51,848 1 6,800 3 4,350 1 21,700 1 40,000 5 9,298 6 76,933 1 6,200 2 2,300 2 7,450 1 2,100 3 13,855 3 9,000 1 5,500 1 2,200 2 5,600 1 77,000 1 1,000 1 47,000 3 110,078 1 9,500 2 75,000 1 3,300 2 5,517 3 31,946 Kendall Knox Lake LaSalle Lee Livingston Logan Macon Macoupin Madison Marion Marshall Mason Massac McLean Montgomery Morgan Moultrie Ogle Peoria Richland Rock Island St. Clair Saline Sangamon Schuyler Shelby Tazewell 29 Table 2-1 (cont'd.) P Total Number of Total Population Served ^°""^y CSO Towns by Combined Sewers Vermillion 4 11,640 Warren 1 14,000 White 1 6,000 Whiteside 2 11,200 Will 5 94,937 Woodford 1 2,366 TOTAL 132 1,247,455 30 oo D_ I— « Q UJ f— O a: CM UJ 1 3: OJ UJ to (U Q I — UJ -Q z: (T3 t— « f- CO 2: H- z: UJ on UJ Q- Q Z <: UJ r>J 1 — 1 oo >- o o to O JD 3 z o c_) -o c o (_) E a> +-> 00 j- (U 00 CD fO +-> c (1) a s- O) Q- c o o u_ I/) 0) •r- 4-> •r— c o J- J3 o c c: o o cr» o 00 o CO I o I t— ( o ID o I o ro O n I .—I C\J o CM I o c o >, ,— -r- -•-> »0 ■»-> -r- 4-> (O »4- C O r— O 13 »- => ^ CL E O O Q. O cn en cvi a> ro CSJ T-H r-^ CTl o c>j CJ CO CVI f\J ro LO CJ CVJ CSJ CO cv 00 OsJ in CT> lT) VO .-I ^ I CD o 00 V .— < un o o o o un o I .-• CD O O O O o m .-• CD o o o o in cu .—I C\J o o o o o o C\J ro O O O O O O ro "^a- I .-« o o o o o o o <:3- in I .—10 o 00 o 00 ~ » CD CD O UD in UD A 31 Table 2-3 GRANT STATUS OF AFFECTED MUNICIPALITIES Phase in Grants Program Step 1 Step 2 Step 3 CSO Amendment Number of Municipalities 98 37 29 25 Thus, of the 132 municipalities identified with combined sewers, 74 per- cent have been engaged in the lEPA process of construction grants. Of those currently involved in Step 1, 2, or 3 funding, 25 communities are conducting specific CSO evaluations of their systems. This study is a detailed report examining the CSO situation in the municipalities and the pertinent items of resolution. Those not identified within the funding process may be awaiting funding for initiation of a CSO project. There appear to be only a few instances where municipalities are not involved in the grants program. The funding of Step 1,2, and 3 programs are determined on a priority number index for each community. This priority is determined according to the additional treatment processes required, overloading, rehabilitation, the Municipal Discharge Index, and other factors. Federal and state funds are available for Steps 1, 2, and 3 for projects with a priority ranking between 1 and 806. Those projects ranked above 806 are eligible for Step 1 only. Upon evaluation of the Step 1 plan, the ranking may be re-evaluated and lowered to a number between 600 and 806. For the purposes of this study, the projects with priority numbers above 806 receive only Step 1 funding. Exhibit 1 indicates the priority number of alT projects in which some portion of CSO treatment is evaluated. A municipality may have more than one project planned which is related to CSO. Thus, the number 32 of projects exceeds the number of affected communities. Table 2-4 sum- marizes these numbers according to funding probability. The priority index is a general indicator since priorities above 600 may be re-evaluated. Table 2-4 SUMMARY OF PRIORITY NUMBER OF CSO PROJECTS Priority Number of Project Number of Projects - 200 34 201-600 47 601-806 15 G.T. 806 _61 Total 157 According to Table 2-4, Step 1, 2, and 3 funds are available for 96 or 61 percent of the projects related to CSO. The remaining 39 percent of the CSO projects are only eligible for Step 1 funding. Thus, there may never be adequate state or federal funds to complete CSO control for 39 percent of the itemized projects. Those projects which are eligible for funds are affected by the design criteria specification Rule 602 (c) of the Illinois Water Pollu- tion Regulations and the program guidance (PG-61) of U.S. Environmental Protection Agency. These criteria are described in the following section. 2.4 Treatment Requirements of Rule 602 Versus U.S. EPA Funding Criteria Both federal and state pollution agencies desire to control com- bined sewer overflows. The degree of control required, however, is expressed in different terms by each agency. This difference has compli- cated funding decisions and could have future impacts upon municipalities. 33 According to Rule 602 of the Illinois Water Regulations, combined sewer overflows must be sufficiently treated to prevent water quality vio- lations. This treatment generally consists of storage and secondary treat- ment for first flush plus primary treatment and disinfection of ten times the average dry weather flow. An lEPA procedural statement describes first flush as the "volume of water needed to carry solids or BOD concentrations g in excess of the normal dry weather level." This volume would vary depend- ing upon the sewer system characteristics, such as drainage area served, percent combined sewers, sewer capacity, and so forth. Thus, the treatment costs of combined sewer overflows consist of the following: 1. Storage capacity for first flush Z. Secondary treatment capacity to handle first flush flows. 3. Primary treatment and disinfection of flows up to ten times the dry weather flow. Thus, a specific treatment level or its equivalent is required by Illinois regulations. This treatment scheme can be expected to reduce BOD loadings on average by a certain percent. If water quality violations persist, then additional controls may be necessary. The U.S. Environmental Protection Agency funds CSO projects on the basis of their cost-effectiveness. Program Guidance Memorandum PG-61 sum- marizes the criteria for project approval in the following way: 1. The analysis required above has demonstrated that the level of pollution control (combined sewer overflow treatment) will be necessary to protect a beneficial use of the receiving water even after technology based standards required by Section 301 of P.L. 92-500 are achieved by industrial point sources and at least secondary treatment is achieved for dry-weather municipal flows in that area. 2. Provision has already been made for funding of secondary treat- ment of dry-weather flows in the area. 3. The pollution control technique proposed for combined sewer over- flow is a more cost-effective means of protecting the beneficial use of the receiving waters than other combined sewer pollution control techniques and the addition of treatment higher than secondary treatment for dry-weather municipal flows in the area. 34 4. Tbe marginal costs are not substantial compared to marginal benefits. The U.S. EPA funding decision is only assured if it is cost-effective and the marginal costs of pollutant reduction do not exceed the marginal benefits or pounds of pollutant removed. The U.S. EPA will only fund up to the point that the incremental benefits exceed the incremental costs or the "knee of the curve." This may or may not be equivalent to the level of treatment specified by the Water Regulations. The lEPA recognizes the difference in funding evaluations and recommends the discharger seek regulatory relief from Rule 602 (c) if the funded level of treatment which maintains water quality is less than that specified in Rule 602 (c). The water quality determination is based upon simplified stream modelling for towns of less than 10,000 population and more sophisticated modelling technique for larger commun- ities. If these dischargers do not obtain a site specific exemption from the Pollution Control Board, then the lEPA cannot approve grant funds since Rule 602 (c) is not fulfilled. The number of dischargers which may be impacted by the difference in state and federal funding is presently unknown. Since the U.S. EPA policy has taken effect, only a few municipalities have applied for construction funds. This difference in philosophies, however, is expected to impact the 132 municipalities which must treat CSO. 2.5 CSO Characteristics of Affected Municipalities The combined sewer characteristics of each affected discharger are unique, and they can only be evaluated on a case-by-case basis. The basic treatment facilities, number of overflow points, length of combined sewer, and percentage of combined sewer are enumerated in Exhibit 2. All facilities had secondary treatment in place with the exception of two dischargers. However, only 20 of the 132 dischargers indicated that excess flow facilities are currently in place. Table 2-5 summarizes the relative percentage of combined sewers in the affected 35 towns. Over half of the communities represent a 90 to 100 percent combined sewer system. The remainder are distributed evenly from to 90 percent combined sewers. Table 2-5 DISTRIBUTION OF PERCENTAGE OF SEWER SYSTEMS COMBINED Percentage of Popu 1 at ion Served by Combined Sewer Number of Municipalities 0- 10 4 11- 20 7 21- 30 5 31- 40 5 41- 50 9 51- 60 3 61- 70 5 71- 80 5 81- 90 5 91-100 54 Total 102 Table 2-2 determines the importance of town size versus percentage of combined sewer for those identified municipalities. The distribution of towns served by 90 to 100 percent combined sewers is predominantly intermediate-sized communities of 10,000 to 15,000 population. The impact of combined sewer overflow treatment is therefore important to intermediate-sized communities. 36 37 3. EVALUATION OF COMBINED SEWER OVERFLOW CONTROL COSTS 3. 1 Introduction Control or reduction of combined sewer overflows can be attained at various levels and varying costs. Federal and state funding of up to 75 percent of CSO project costs are available; however, the criteria for obtaining funds differ for each. Treatment requirements for com- bined sewer municipalities in Illinois are based upon achieving a speci- fied level of treatment for each discharger, while the federal funding criteria is related to ascertaining cost-effective water quality improve- ment. Cost estimates are provided of those capital and operating costs for achieving compliance with Rule 602. However, there are several alter- native levels of control considered for CSO treatment as well as the asso- ciated costs. This range of control costs is intended to provide an indi- cation of the general economic efficiency of the existing Rule 602. Those alternatives considered in the cost estimating are specified as follows: 1. Present Illinois Water Pollution Regulations (Rule 602) speci- fying full treatment of first flush and additional flows up to ten times the average dry weather flow receiving primary treatment and chlorination. 2. Variations of Rule 602 are considered such as secondary treat- ment of first flush plus five times and two times the dry weather flow receiving primary treatment and chlorination. 3. Deletion of the disinfection requirement is evaluated. 4. Exemption of municipalities located upon major streams from Rule C02. 5. Exemption of municipalities under a population of 3000 served by combined sewers from Rule 602. 6. Elimination of Rule 602. 38 7. Use of best management practices (BMP) in place of Rule 602 for towns with priority number greater than 306. These alternative levels of CSO control will be described herein as they impact the Illinois municipalities with combined sewer systems. 3.2 Combined Sewer Overflow Control Technologies There are three types of CSO control technologies considered to reduce pollutant loadings to streams. Table 3-1 lists the available methodologies for source controls, collection system controls, and treatment facilities. The only technologies utilized in this study are those demonstrated as being cost-effective and practical in Illinois applications. The source control of combined sewer flushing and collection system controls of system management, flow reduction techniques, and sewer separation are briefly described as controls which can be effective. Treatment facilities of storage, sedimentation, and disinfection, which are the standard requirements in Illinois, are also utilized. The following descriptions are excerpted from the 1978 Needs Survey to brii control and associated unit costs. from the 1978 Needs Survey to briefly summarize the technologies of CSO 3.2.1 Combined Sewer Flushing The major objective of combined sewer flushing is to resuspena deposited sewage solids and transmit these solids to the dry-weather treatment facility before a storm event flushes them to a receiving water. Combined sewer flushing consistsof introducing a controlled volume of water over a short duration at key points in the collec- tion system. This can be done using external water from a tanker truck with a gravity or pressurized feed or using internal water detained manually or automatically. Implementation requires a com- plete knowledge of how the existing collection system is operating. Combined sewer flushing is most effective when applied to the flat portion of the collection system. Procedures are available to estimate the quantity and distribution of dry-weather deposition in sewers and for locating theoptimum sites for sewer flushing. A recent feasibility study of combined sewer flushing indicates that manual flushing using an external pressurized source of water is most effective. No significant gain in the fraction of load removed was achieved by repeated flushing, and 70% of the flushed solids will quickly resettle. Therefore, repeated flushing in a downstream 39 Table 3-1 COMBINED SEWER OVERFLOW CONTROL TECHNOLOGIES Source Controls Street Cleaning Combined Sewer Flushing Catch Basin Cleaning Collection System Controls Existing System Management Flow Reduction Techniques Sewer Separation Inline Storage Treatment Facilities Offline Storage Sedimentation Dissolved Air Flotation Microscreens High Rate Filtration Swirl and Helical Concentrators Chemical Additives Coagulation and Flocculation Disinfection Biological Treatment SOURCE: CH^M Hill, 1978 Needs Survey , U.S. EPA, 430/9-79-003, Feb. 1979) 40 sequence is probably necessary to achieve significant pollutant reduc- tions. Process efficiency is dependent upon flush volumes, flush discharge rate, sewer slope, length, diameter, wastewater flow rate, and efficiency of the wastewater treatment device receiving the resus- pended solids.^* The capital costs associated with an automatic sewer flushing system were estimated in 1978 dollars as $9000 per flushing station and an operating and maintenance cost of $1,630 per year. Previous studies indicated that flushing stations are needed for every ?.25 to 4.5 acres of area served. Such a technique may reduce the annual BOD^ and suspended solids watershed loading by 40 percent. These unit costs and removal efficiencies will be utilized to develop aggregated costs and loading reductions for Illinois communities. 3.2.2 Existing System Management The major objective of collection system management is to implement a continual remedial repair and maintenance program to provide maximum transmission of flows for treatment and disposal while minimizing overflow, bypass, and local flooding. It requires patience and an understanding of how the collection system works to locate unknown malfunctions of all types, poorly optimized regulators, unused in- line storage, and pipes clogged with sediments in old combined sewer systems. The first phase of analysis in a sewer system study is an exten- sive inventory of data and mapping of flowline profiles. This infor- mation is then used to conduct a detailed physical survey of regulator and storm drain performance. This type of sewer system inventory and study should be the first objective of any combined sewer over- flow pollution abatement project.^* The cost of a detailed CSO inventory is considered to be a minimum of $100,000, regardless of town size. This value is based upon 25 current CSO studies being conducted in Illinois. Larger communities pay higher costs but the $100,000 is expected to be incurred by even the smallest municipality. Sewer system evaluations have been conducted by an additional 12 percent of the affected communities, according to Exhibit 1. Thus, over 30 percent of the affected municipalities have had or are presently engaged in a detailed analysis of their sewer system. *From Reference 6, pp. 3-2 and 3-3. 41 3.2.3 Flow Reduction Techniques The major objective of flow reduction techniques is to maximize the effective collection system and treatment capacities by reducing extran- eous sources of clean water. Infiltration is the volume of ground water entering sewers through defective joints; broken, cracked, or eroded pipe; improper connections; and manhole walls. Inflow is the volume of any kind of water discharged into sewerlines from such sources as roof leaders, cellar and yard drains, foundation drains, roadway inlets, commercial and industrial discharges, and depressed manhole covers. Combined sewers are by definition intended to carry both sanitary wastewater and inflow. Therefore, flow reduc- tion opportunities are limited. Typical methods for reducing sewer inflow are by discharging of roof and areaway drainage onto pervious land, use of pervious drainage swales and surface storage, raising of depressed manholes, detention storage on streets and rooftops, and replacing vented manhole covers with unvented covers. Flow reduc- tion requires a thorough analysis of the existing sewer system to maximize the effective capacities of collection systems and treat- ment works. °* Disconnection of downspouts may reduce a sewer overloading problem 3 as was cited in the case of Springfield. Also, the use of retention basins, as in Arlington Heights, may reduce the potential for basement backup and 3 flooding. The cost of disconnecting roof drains has been estimated at $50.00 per pound of BOD^. removed.'' This is a high cost in comparison to sewer flushing at $.94 to $4.00 per pound of 800^ removed. Also, the cooper- 7 ation of building owners is considered difficult to obtain in establishing a disconnection program. 3.?. 4 Sewer Separation Sewer separation is the conversion of a combined sewer system into separate sanitary and storm sewer systems. Separation of municipal wastewater from stormwater can be accomplished by adding a new sanitary sewer and using the old combined sewer as a storm sewer, by adding a new storm sewer and using the old combined sewer as a sanitary sewer, or by adding a "sewer within a sewer" pressure system. If combined sewers are separated, it must be remembered that storm sewer discharges may contribute a significant pollutant load relative to secondary wastewater treatment plant effluent and, therefore, may require some type of control even after the sewer systems are separ- ated. For a small watershed sewer separation may be a cost-effective control alternative.* ■From Reference 6, pp. 3-4, 42 Sewer separation is considered a feasible alternative when the drain- age area of less than 200 acres is affected. Costs of sewer separation vary, depending upon the characteristics of the municipality. Table 3-2 presents a summary of sewer separation costs proposed in Illinois for various towns. These data are compared to the following general cost equa- tion developed in the 1978 Needs Survey: 1) C35 = 1,779 X PD where C^c- = Capital cost of sewer separation in dollars per acre PD = Population density of the combined sewer service area A simple linear regression of the data in Table 3-2 yielded the follow- ing cost equation for Illinois towns: 2) C^^ = 830 X PD In developing costs of separate sewers, equation 2 was considered more applicable to Illinois communities. 3.2.5 Inline and Offline Inline and offline storage result in the containment of large volumes of stormwater for later release to the treatment plant. Inline storage is a more complex method which requires excess capacity in the sewer system and a series of automatic or manual controls for directing excess flows. Such a system is being planned for Peoria; however, smaller towns may not have the resources to operate such a system. Offline storage or excess flow storage at the treatment facility reduces overloads to the plant. Such excess flow facilities require land availability but represent small operating costs. Three types of basins may be constructed: earthen basins, uncovered concrete basins, and covered concrete basins. 43 Table 3-2 COSTS OF SEWER SEPARATION FOR ILLINOIS MUNICIPALITIES M ■ • 1-4. T 4. T r 4. d-a r 4. d- b Population Density, Mumcipality Total Cost, $ Cost, $ per acre ^„ ^, ■" ^ -^ 5 -^ r- persons/acre Belleville 77,100,000 26,600 13.7 Georgetown 6,540,000 2,600 1.6 Lockport 1,160,000 11,000 6.1 Morrison 668,000 390 24.7 North Utica 567,000 11,000 21.6 Olney 1,000,000 37,000 37.0 Streator 31,400,000 8,800 4.2 Spring Valley 2,450,000 6,200 14.1 Thornton 265,000 8,500 12.0 Westville- Belgium 6,610,000 2,900 2.4 Notes: a) All costs adjusted to 4Q, 1979 values. b) Cost per acre based on total cost divided by number of acres served by combined sewers. SOURCE: lEPA files, engineering reports, and U.S. EPA Needs Survey Data Printout. 44 In Illinois excess flow facilities may consist of the use of pieces of older equipment or lagoons which have been replaced. To estimate the storage needs for various levels of CSO control, the construction costs associated with earthen basins without covers are utilized. Figure 3-1 depicts the cost of storage in 1976 dollars. These values are updated to 1979 for estimating purposes. 3.2.6 Sedimentation The major objective of sedimentation is to produce a clarified efflu- ent by gravitational settling of the suspended particles that are heavier than water. It is one of the most common and well-established unit operations for wastewater treatment. Sedimentation also provides storage capacity, and disinfection can be effected concurrently in the same tank.*" Primary treatment (which includes sedimentation) is a requirement for CSO in Illinois. Sedimentation appears to be the most common form of primary treatment, and therefore costs of sedimentation facilities are utilized for the evaluation of regulatory alternatives. Capital cost and operating cost estimates of sedimentation facilities are based upon equations 3 and 4, respectively. These equations were 3) C^ = 52,000Q°-^^^ 4) Cq3 = 3,870 qO-702 _^. ^^^^0 qO-212 + 4 ^^5 qO.779 where Q = flow in MOD C^ = capital cost in 1978 dollars. Cq^ = Operating cost in 1978 dollars. utilized in U.S. EPA cost estimates of CSO treatment and are based in 1978 dollars. *From Reference 6, pp. 3-4. 45 S o z o I- u ta t- Z o u 10 100 STORAGE CAPACITY - MILLION GALLONS Figure 3-1 COST OF STORAGE RESERVOIR SOURCE: Benjes, Henry, H., Cost Estimating Manual --Combined Sewer Overflow Storage and Treatment , U.S. EPA-600/2-76-286, Dec. 1976. 46 3.2.7 Disinfection The major objective of disinfection is to control pathogens and other microorganisms in receiving waters. The disinfection agents commonly used in CSO and stormwater treatment are chlorine, calcium or sodium hypochlorite, chlorine dioxide, and ozone. They are all oxidizing agents, are corrosive to equipment, and are highly toxic to both microorganisms and people. Physical methods and other chemical agents have not had wide usage because of excessive costs or operational problems. The choice of a disinfecting agent will depend upon the unique characteristics of each agent, such as stability, chemical reactions with phenols and ammonia, disinfecting residual, and health hazards. Adequate mixing must be provided to force disinfectant contact with the maximum number of microorganisms. *° Disinfection of CSO is a requirement of Rule 602 of the Illinois Water Pollution Regulations. The detention time and dosage rate vary with each application in order to obtain a certain level of disinfection. In Illinois there are several municipalities which have installed or are installing chlorination facilities. The value of chlorination has been questioned since several studies have raised doubts regarding the use of bacteria count limits for contact 8 8 recreation. It seems the same pathogens are present in reservoirs. The environmental effects of chlorination will be discussed in the following chapter. To determine the capital and operating costs of disinfection, the following equations are utilized: 5) Cj = 73,100 + 6,020 Q^ 6) Cqj = 2,060 Q°-^^^ + 1,320 Q^*^^ where Q = design flow in MGD C. = capital costs in 1978 dollars Cqj = operating costs in 1978 dollars *From Reference 6, pp. 3-5. 47 These equations were developed for a range of chlorination facilities with a dosage range of up to 7 mg/£. 3.2.8 Cost-Effectiveness of Control Technologies The general cost-effectiveness has been evaluated by the U.S. EPA of the technologies described above. The particular value of any technology would vary with the site specific characteristics of the application. The following assumptions were utilized to develop a range of feasibility and unit costs of various technologies: 1. population density of 16.73 persons per acre 2. annual rainfall of 33.4 inches 3. BODc discharge of 135.2 pounds per acre per year 4. runoff rate of 16.5 inches per year. Table 3-3 summarizes the expected costs and BOD^. removals of various controls. According to the U.S. EPA studies, ' the most feasible control alternative for drainage areas larger than 2,000 acres where greater than 50 percent BOD^ removal is required is storage and treatment. For smaller ones, source controls or sewer separation may be more cost-effective. To place the requirements of Rule 502 in perspective with this general evaluation, the same general assumptions were utilized for storage and secondary treatment of first flush and primary treatment of ten times the dry weather flow. The values shown in Table 3-3 for three sizes of drainage areas indicate that the removal costs are higher for smaller areas (20 acres) and lower for the large areas (2000 acres) than those estimated for Levels 1, 2, 3, and 4. The use of sewer flushing appears more cost- effective than storage and treatment for the smaller areas based upon the general assumptions utilized. These general indications of cost-effectiveness of various control technologies are presented as a basis for examining the impact of Rule 502 and its alternatives. With limited funding available, the cost- effectiveness of CSO control technologies may become important in evaluating alternatives. 48 Table 3-3 RANGE OF UNIT COSTS AND POLLUTANT REMOVAL FOR CSO CONTROL TECHNOLOGIES Control Range of BOD Removal , 1o Range of Costs, $/lb BOD. Maximum BODj Removal , V Streetsweeping 2-11 Catch basin cleaning Sewer Flushing 18-32 Sewer Separation 54-65 Roof Drain Disconnection Site specific Storage/Treatment^ Drainage area of 2000 acres Level 1 10-16 Level 2 16-35 Level 3 35-61 Level 4 61-87 Level 5 87-95 Storage/Treatment 20 acres 67 200 acres 67 2000 acres 67 3.00-7.50 >50.00 0.94-4.00 24.00 >50.00 4.70-6.00 3.40-4.70 3.10-3.40 3.10-4.20 4.20-14.00 9.50 4.10 1.90 12 0.5 54 65 Site specific 25 50 79 90 95 Note: a) Level 1 = Storage Level 2 = Stoage and microscreening Level 3 = Storage, microscreening and sedimentation flocculation Level 4 = Level 3 plus high-rate filtration Level 5 = Level 4 plus dissolved air flotation b) Storage/treatment defined by Rule 602. SOURCE: Reference 7, pp. 7-11. 49 3.3 Costs of Alternative Levels of CSO Control The capital and operating cost of controlling CSO is estimated for seven alternatives for the 132 municipalities in Illinois. Those control levels considered for evaluation are as follows: 1. Existing 602 (Secondary treatment of first flush and primary treatment and disinfection of ten times the dry weather flow) 2. Secondary treatment of first flush and primary treatment of five and two times the dry weather flow. 3. Deletion of the disinfection requirement from Rule 602. 4. Exemption of municipalities located on major streams. 5. Exemption of municipalities under population of 3000. 6. Elimination of Rule 602. 7. Use of management practices for towns with priority number above 806. For 55 municipalities compliance costs with Rule 602 have been estimated in facility plans or other engineering reports. Exhibit 4 summarizes these costs which may represent storage and treatment or sewer separation, which- ever is more economical. Exhibit 3 values also include costs for trans- porting flows, sewer rehabilitation, and costs incurred to correct the CSO problem. Cost estimates for the remaining 82 municipalities are based on the general cost relationships previously described in this section. Figure 3-1 and equations 3, 4, 5, and 6 are utilized to develop facility costs. Two additional factors must be considered in estimating costs. First, the combined sewer system has a series of overflow points and to treat the overflows requires transport to the treatment plant. Therefore, an interceptor is required for carrying overflows or treatment must occur at the overflow point. Secondly, depending upon the site specific character- istics, the most cost-effective solution often is to separate a portion 50 of the combined sewers and treat the remaining flows. To provide an order-magnitude cost estimate only store and treat or separate sewers are considered. The cost of pumping CSO is added to the capital costs of control facilities, but additional transport costs were not included because of the need for detailed site evaluations. The design flow for cost estimating is taken from Exhibit 5, which summarizes the flow information for each municipal discharger. The average effluent flows are presented as well as those CSO flows requiring primary and secondary treatment. Rule 602 criteria indicate first flush must receive full secondary treatment. Since site specific data are lacking, a rule-of-thumb volume estimation of 2.5 times DWF is utilized.* Primary treatment of ten times the dry weather flow is also required. Costs for Rule 602 are estimated on these design criteria. Table 3-4 presents the estimated capital and operating costs of achiev- ing compliance of Rule 602. For the 132 affected municipalities capital costs of $476 million and an annual cost of $72.5 million may be incurred. These costs represent conservative cost estimates since no costs are allo- cated for the construction of new interceptors for transport of overflows for 77 of the facilities affected. Forty percent of the capital costs included as equivalent treatment are attributed to sewer separation pro- jects and the remainder represents store and treat alternatives. The costs of compliance for alternatives B, C, and G are calculated in a direct manner from the costs associated with Rule 602. These values are summarized in Table 3-5 for the affected municipalities and represent incremental reductions in treatment costs. For projects representing sewer separation, the costs of smaller store arid treat volumes are assumed to reduce the viability of sewer separation as a cost-effective solution and equivalently lower treatment costs are incurred. Since there are economies of scale in treatment, the smaller volumes treated do not reduce the costs proportionately. However, there is a 42 percent reduction in capital costs from $476 million to $275 million for reducing the treat- ment volume by half. Also, reducing the volume to one-fifth results in *This estimating technique was utilized by lEPA prior to 1971. 51 Table 3-4 CAPITAL AND OPERATING COSTS OF COMPLIANCE WITH RULE 602^ Treatment Capital Operating Annual Requirement Cost, $ Cost, $ Cost, $^ Storage for first flush 4,500,000 363,000 900,000 Pumping Costs 43,000,000 500,000 5,530,000 Primary Treatment 21,000,000 1,490,000 4,000,000 Disinfection 9,300,000 1,080,000 2,170,000 Equivalent Treatment^ 398,000,000 18,600,000 59,900,000 Total cost 476,000,000 22,000,000 72,500,000 Note: a) 132 sites in 4Q, 1979 dollars for all communities outside Cook County. b) Equivalent treatment reflects costs of sewer separation, where more economical, or costs or storage and treatment from Exhibit 3. c) Annual cost based on interest rate of 10%, 20 years for capital charges added to operating cost. 52 Table 3-5 SUMMARY OF ALTERNATIVE COSTS Treatment Alternative Capital Cost, Annual Cost, $ $ A) Rule 602 476,000,000 72,500,000 B) 1) Primary treatment of 5x flow plus first flush & Cl^ 246,000,000 51,900,000 2) Primary treatment of 2x flow plus first flush & Cl^ 151,000,000 36,000,000 C) Rule 602 without disinfection 464,000,000 69,200,000 D) Exemption of municipalities on major streams 341,000,000 57,000,000 E) Exemption of municipalities of combined sewer population 426,000,000 68,200,000 under 3000 F) Use of management practices for towns with priority numbers above 806^ 1) BMP communities 91,000,000 17,000,000 2) other communities 307,000,000 44,500,000 G) Elimination of Rule 602^ 38,000,000 5,500,000 Note: a) BMP costs based on calculated costs of $61 million for capital and $11.5 million for operating for 31 of 46 municipalities where sufficient data available^ assumed these 31 communities represented 70% of total costs based on total area of these towns, b) Costs incurred represent facilities in Step 3 where funds are committed. 53 a capital cost reduction of 66 percent. The elimination of disinfection facilities for CSO, Alternative C, diminishes capital costs by $12.4 million and operating costs by $3.3 million. There are 37 communities with populations of less than 3000 being served by combined sewers. The CSO control costs for these communities are deleted assuming an exemption (Alternative E) exists. Elimination of 27 percent of the dischargers results in only a 11 percent reduction in the total capital cost and 6 percent in annual costs for Illinois communities. Alternative D considers exemption of those combined sewer systems located near a receiving stream whose low flow exceeds 400 cfs. There are 27 communities located on such waterways. Deleting the costs of these communities results in a decrease of $135.0 million in capital costs and annual costs of $15.5 million. Another alternative evaluated for towns with uncertain funding oppor- tunities is the use of best management practices in place of Rule 602. There are 46 municipalities with priority numbers above 806. These com- munities are assumed to utilize sewer flushing techniques at a capital cost of $1200 per acre and operating cost of $220 per acre. Thus, these communities incur capital and operating costs of approximately $91 million and $17 million, respectively. Such costs result in reduction in expenses incurred with Rule 602 of $78 million for capital and $11 mil- lion for operating costs. These seven alteratives described in Table 3-5 represent various levels of control for combined sewer communities with the exception of those located in Cook County. Funds committed to communities in Step 3 are estimated at $38 million. This means over $400 million has yet to be committed to resolving the CSO problem. This cost estimate does not include the costs of engineering studies and designs plus transport costs of overflows. Therefore, these estimates are conservative values. The values obtained in engineering studies submitted to lEPA and U.S. EPA are site specific estimates and compose 80 percent of the total cost. 54 The remaining costs developed from projections using cost equations may vary from actual costs by as much as 50 percent due to site specific con- siderations. 55 4. WATER QUALITY IMPACTS OF GSO 4.1 Introduction The effects of combined sewer overflows are so variable that it is difficult to generalize regarding environmental impacts. The discharge of organic material, nutrients, sediment, and other pollutants may have a serious impact upon the receiving stream. The variables which influence the degree of CSO importance are CSO constituents and their concentrations, rainfall frequencies, CSO frequency, and the receiving stream character- istics (size, hydrology, uses, and downstream characteristics). This information must then be evaluated on a site-specific basis. To provide some indication of the relative importance of CSO in terms of environmental degradation, general background information on the 132 affected municipalities is developed utilizing relationships obtained from the literature. Definitive CSO studies are lacking in Illinois, and the CSO evaluations of five communities serve as indi- cators of the varying nature of water quality impacts. CSO pollutant loadings are calculated based upon relationships developed by site studies and literature review. The effects of the seven alternative CSO controls requirements upon pollutant loadings are then quantified. The impact of such pollutant loadings upon stream uses can only be described in a qualitative manner because of data limitations. 4.2 CSO Pollutant Characteristics Since there are many pollutants associated with CSO, the indicator pollutants, which affect the receiving stream use, are considered of most importance. Table 4-1 summarizes those pollutants impacting aesthetics, fish and wildlife, and recreational uses of water. Floatable solids detract from the aesthetics of the receiving stream, especially in urban areas, where they collect on banks. Suspended solids can have adverse effects upon fisheries, depending upon the natural stream conditions. Receiving streams with high natural suspended material are 56 Table 4-1 CSO POLLUTANTS AFFECTING WATER USES Aesthetics Floatable solids Settleable Solids Fish and Wildlife Suspended solids Carbonaceous BOD Nitrogenous BOD Dissolved Lead Phosphorus (for lakes) Recreation Suspended solids Carbonaceous BOD Nitrogenous BOD Dissolved lead Phosphorus (for lakes) Fecal col i form SOURCE: Reference 6, p. 2-2. 57 considered less "sensitive" to additional materials than those streams with low turbidity. Turbidity or suspended solids impact the type of fishery attainable in a stream. According to a U.S. EPA report, the following ranges are expected: a) There is no effect of less than 25 mg/£ suspended solids upon fisheries. b) Good or moderate fisheries are maintained where the suspended solids range from 25 mg/£ to 80 mg/il. c) Waters containing 80 mg/£ to 400 mg/il suspended solids are not likely to support good fisheries. d) Only poor fisheries are likely to be found where suspended solids exceed 400 mg/£. Carbonaceous and nitrogenous BOD directly contribute to the dissolved oxygen depletion in the stream. Depending upon the stream size and relative size of the CSO, the dissolved oxygen levels may be affected. Character- istics considered important in evaluating the CSO impact on a site specific basis are the following: a) Upstream BODj. annual loading b) Dry weather annual BOD^ loading from municipal and industrial treatment plants. c) Annual BODj. loading from CSO. d) Receiving stream flow in wet weather and dry weather. e) Receiving water reaeration rate. f) Waste decay rates for CSO and treatment plant effluents. Thus, site specific information is necessary for an evaluation of dis- solved oxygen demand. To maintain aquatic communities the Illinois general stream use dissolved oxygen criteria are a minimum of 5.0 mg/il at any time and not less than 6.0 mg/£ during 16 hours of any 24-hour period. 58 Such dissolved oxygen levels are to insure the maintenance of fish popu- lations. Lower dissolved oxygen levels may be tolerated for short periods of time without fish mortality, as indicated in Figure 4-1; however, point source control has been designed at levels to achieve the general use stream standard. Recreational pursuits, including body contact recreation, depend upon achieving acceptable bacteriological levels reported as fecal coli- form. CSO levels of bacteria run into the thousands and may impact recre- ational use. There is some question as to the appropriateness of utilizing fecal coliform as an indicator. However, many water quality and effluent standards utilize fecal coliform. In Illinois there is a regulatory pro- posal to delete fecal coliform from the effluent standards. Additional discussion of the merits of disinfection is presented in Section 4.6. The impact of each pollutant upon stream use varies according to its concentration and persistence in the stream. Figures 4-2 and 4-3 depict the difference in effects of floatable solids, bacteria, dissolved oxygen, and suspended solids. Bacteria have a high die-off rate and thus their impact may last only a few days. However, suspended solids which are carried in the stream may have an effect for more than a week and up to a year. The stream distance affected may vary from a local reach to an entire region, depending upon the parameter affected. The quality of combined sewer overflows varies with rainfall fre- quency and intensity. Typically, the first flows associated with storms "flush" organic material deposited in the sewers. This "first flush" discharge may have a higher organic loading than normal sanitary waste- water, depending upon the interval between overflows. With continued rainfall, dilution of wastes occurs and the organic concentrations decrease. Typical or average concentrations of CSO pollutants are compared to raw sewage and stormwater in Table 4-2. First flush concentrations are equivalent to raw sewage; however, extended flows have concentrations similar to stormwater. In fact, the suspended solids concentrations of 100.0 n 10.0- a: O I < cr D O 1.0- 0.1. 72 Hours (3 Days) LETHAL 4 Hours — I — 0.5 — r— 1.0 ?9 ^. / /--/- / // / // 1.5 SAFE 2.0 -| — 2.5 DISSOLVED OXYGEN, MG/L 10%-INDICATES MORTALITY PERCENTAGE — r~ 3.0 — r 3.5 FIGURE 4-1. Mortality of Juvenile Brook Trout due to low DO levels. SOURCE: Reference 6, p. 2-6, 60 10' 10' 10' Seconds 10* 10' I0« 10' Floaiables Bacteria Dissolved Oxygen Suspended Solids Nutrients Dissolved Solids Acute Toxic Effects Long Term Toxic Effect Day Montfi Year Hour Week Season Decade Figure 4-2 Time Scales for Storm Runoff Water Quality Problems. Source Dnscoll, E D and J L fVlancini Assessment of Benefits Resulting from Control of Combined Sewer Overflows' , p 9 presented at EPA TEcfinology Transfer Seminars on Combined Sewer Overflow Assessment and Control Procedures 1 978 61 Miles 10' 103 lOJ 10" (5 Ft) (50 Ft.) (500 Ft.) 10' 10' 10' Hydraulic Design Floaiables Bacteria Suspended Solids Dissolved Oxygen Nutrients Toxic Effects Dissolved Solids K Local h H Region Figure 4-3 Basin Space Scales for Storm Runoff Water Quality Problems. Source Driscoll, E D and J L Mancmi, 'Assessment of Benefits Resulting from Control of Combined Sewer Overflows", p 10. presented at EPA Technology Transfer Seminars on Combined Sewer Overflow Assessment and Control Procedures. 1 978. 62 stormwater may far exceed that of CSO, depending upon the rain event. The actual loading in pounds contributed by CSO or storm water depends upon the drainage area, runoff coefficient, and storm characteristics. The organic loading of first flush is a primary concern because of the dissolved oxygen demand. Thus, even though combined sewers discharge on an infrequent basis (estimated between 2% and 15% of time), the higher waste concentrations may impact stream quality and its aquatic life all year. 4.3 CSO Water Quality Impacts in Illinois Combined sewer communities are distributed throughout the state on small and large streams. The water quality impact relates to the stream size, aggregation of discharges, and size of CSO discharges. There are very limited data regarding the extent and duration of CSO impacts on Illinois streams. Quantification of stream effects would require prolonged (over a year) field studies at each site. General field evaluations have been conducted for 54 of the 132 dischargers. The results of these general descriptions are described according to receiving stream size and the type of water quality impact. The overflow of combined sewers generally discharges to the same receiving stream as the wastewater treatment plant. There may be smaller tributaries involved as well but the receiving stream of the wastewater discharge is considered indicative of the watershed of concern. For purposes of general analysis and description, the receiving streams are categorized according to their low flow characteristics. The low flow of a stream is typically utilized for design purposes and water quality evaluations. Three categories of receiving streams are identi- fied as the following: Intermittent streams - The seven day ten year low flow is zero for these streams. Intermediate streams - Those streams with a seven day ten year low flow greater than zero but less than 400 cfs (cubic feet per second) are considered intermediate. This includes the Fox River, DuPage River, Vermilion River, and others. 63 Table 4-2 CONCENTRATIONS OF CSO, SEWAGE, AND STORMWATER Typical Concentration of Pollutants, mg/£ Water Source BODc Suspended Solids Total Nitrogen CSO, first flush^ 186±40 522il50 17.6±3.1 CSO, extended flow^ 49±10 166±26 5.5±0.8 Typical Raw Sewage^ 200±10 200^100 40 Stormwater^ 30±170 630±2000 3 Reference 13 ^Values averaged from Lager, J. and Smith, W. "Urban Stormwater Management and Technology," EPA 670/2-74-040, December, 1974. 64 Major streams/rivers - Those streams with a seven day ten year low flow greater than 400 cfs include the Illinois, Mississippi, Kankakee, and other rivers. Exhibit 3 presents the receiving stream categories for the 132 affected dischargers as well as identifying water quality problem areas specified in Needs Survey data baseline. Table 4-3 summarizes the receiving stream data for these facilities. Approximately 50 percent of the affected dischargers are located on intermittent streams and the remainder are divided between intermediate and major receiving streams. Although these categories are defined according to low flows, the combined sewer overflow typically occurs during wet weather events. The ability of the receiving stream to assimilate untreated discharges depends upon the CSO volume and concentration as well as the flow of the stream itself. The categorization of Table 4-4 provides an indication of the stream sizes receiving CSO from various discharger sizes. According to Table 4-4, 68 percent of the towns located Table 4-3 CATEGORIZATION OF RECEIVING STREAMS Stream Type Number of Receiving Streams Number of Streams Identified with CSO Water Quality Problems Intermittent Intermediate Major Lake Michigan Total 62 38 27 _2 129 17 10 10 37 SOURCE: Exhibit 3 65 M I— I UJ c_> oo O '::f 1— ( I— ^ o ^ 0) ID 1 — Ll_ J3 ft3 03 s- +-> OO en O) o O) O) N 00 (/) M- U E 03 O CU O s_ '^ 4-> OO A S- 2 o O 03 03 CU +-> OO 0) 4-> 03 •I — -o O) E S- OO I CD 03 OJ s- 4-> OO ^ Un r— I r— I O <— I OO C\J 00 00 LD 00 OO O OJ .—I OO (T> KD OO oooooooo oooooooo oooooooo Lnounocz>oooo <— li— tOJOO"vfLni£30 O I I I I I I I I o O IX) OO^^^r-<^.-lr-l •^OOOOOOOO A --•OOOOOOOO V I— tunounoooo >-H <— I n3 cr> ro CO ro •— t oo c\j cvi CO oo CO OJ 00 OsJ CO CO oo IX) (XI CO (^ 1^ un E •^ -(-> fO E •r— E e CO fO o T3 c +-> •r— O) c 4-> 1 CD m >> ■o CO X (T3 1 — s- -0 fC cn OJ T3 0) ■0 O) •t— Q c > CD cu 1 — u Q. 1 — •1 — CO CO 4-> 13 CO •1 — O) CO • r— S- x: -0 OJ +-> XI 4-> CO C71 S O) • r— ra =3; 3: _J CQ OJ S- CO fO +-> Q. •I— Q. CO fO Q. CO O) -M X3 O) O) 14- CD M- -0 O) ^ 1 — CO . E I/) 03 E O) 03 S- (1) • 4-> S_ CO CO +-> E CO 03 S- QJ • S- S- •<—> CO +-) fO E ■•-> CO E 03 E 4-> T5 s- E E +j s- O) ro 1/1 4-> 4-> QJ +-> QJ • r— -!-> E +J E ftS OJ 03 s- • r— -(-> •1— O) T3 4-> -a 4-> OJ • 1 — O) E E E E • t— S_ S- s- cu d) 0) E +-> +-> -M E E E •^ •n- •r" T3 O) E E E -t-> fO T5 -a ■0 O) O) OJ +-> +-> +-> fO 03 03 -0 U a E fO ' — ' — ' — ri #\ ^ ri • LO m CM CM E E fO (O •N XI jE 4J +-> 4J +-> 1 — 1 .— 1 CM CO CO S- CO CO O) OJ O) rt > "— "— Ln LO E E E E E •r— •r— •n" •n~ •r— +j 4-) -i-> 4-> +-> fO n3 03 03 03 3 Z3 13 13 13 Q- Cl Q. CL CL Q. CL Q. Cl. CL 4- 4- 4- 4- ■+- CO CO CO CO t/l E E E E E S S s s S 1— 1— 1— 1— 1— cC CQ C_> Q LU 10 CO ly) CO CO CO CO CO CO CO (t3 fO 03 03 03 CO C_) O C_) C_) (_) 68 compared to contributions of point and non-point sources to determine the ultimate resolution of a water quality problem. The following section addresses the statewide impact of CSO. 4.4 CSO Pollutant Loading The actual pollutant loading attributed to CSO depends not only upon the concentration but also upon the rainfall rate, amount of runoff (which is related to land use pattern), and sewer system characteristics. Depending upon the magnitude of the storm event, the impact of CSO would also vary. Therefore, to present some estimate of the magnitude of CSO contributions compared to regular effluent discharges from the associated wastewater treatment plant, an annual average loading of each was developed, Municipal wastewater treatment plants presently report the average and maximum effluent quality on a monthly basis. Exhibit 6 summarizes the effluent data and daily loadings for most of 132 affected municipalities. In some instances reporting data were not available, and in those instances values reported in lEPA field inspections were considered representative of effluent quality. The average annual BOD^ and suspended solids concen- trations of 48 percent of the plants are less than 20 mg/£. and 25 mg/£, respectively. Only 18 percent of the treatment plants exceed an average annual concentration of 30 mg/£ for BOD^ and suspended solids, and many of these facilities have new construction in progress. The evaluation of CSO loadings depends upon the following variables: rainfall, population density, drainage area, number of overflows, and runoff characteristics. Previous studies ' have examined the relation- ship of CSO loadings to the variables mentioned above. Table 4-6 presents the general equations developed in these studies for estimating loadings. These equations are based upon a typical land use pattern, which is 69 Table 4-6 COMBINED SEWER ANNUAL LOADING EQUATIONS Average Area! Load Equations Parameter Combined Sewer Area BOD^ M = (1.92)P(0.142 + 0.218 PD^'^^) + (1.89)P SS M + (39.25)P(0.142 + 0.218 PD^*^^) + (25.94)P TN M + (0.315)P(0.142 + 0.218 PD^°-^^) + (0.28)P PO^ M + (0.0812)P(0.142 + 0.218 PD^°'^^) + (0.071)P Lead M = (0.0126)P(0. 142 + 0.218 PD^°'^^) + (0.0124)P /,, ' ' N = Mopin cv TM X Number of acres draining combined sewer area (lbs/year) BOD,Sb,or TN ^ Notes: M = Areal loading rate, Ib/acre-year. P = Average annual rainfall, inches. PD, = Population density of the developed sewer area, capita/acre. These equations are based on a typical developed land use distribution of 58.4% residential, 14.8% industrial, 8.6% commercial, 18.2% other, and 46.2% undeveloped. SOURCE: Heaney, J. P. et al.. Nationwide Evaluation of Combined Sewer Overflows and Urban Storm-water Discharges , EPA-600/2-77-064. March 1977. 70 indicated in Table 4-6, and this pattern affects the degree and type of runoff received. Such a pattern is associated most specifically with urbanized areas and thus presents only a generalized estimate for the smaller Illinois communities. Drainage area and population density information were available for only 63of the 132 communities. A comparison of the CSO and general efflu- ent loadings of these 63 was considered indicative of the entire grouping of affected communities. Two methods of calculation are utilized for estimating CSO loadings. The equations in Table 4-6 represent an estimation based on annual rain- fall, population densities, and rates of BOD^ accumulation. Another method of calculation is based upon an average BODj. and suspended solids concen- tration of 100 mg/^ and 297 mg/£, respectively, and the area affected for 63 municipalities. Thus, a range of loadings is presented for uncon- trolled CSO loadings. Table 4-7 depicts the relative magnitude of untreated CSO loadings to effluent loadings of the 63 communities. The annual BODj. loading attributed to untreated CSO is smaller than the normal effluent loadings of the associated wastewater treatment plants utilizing the calculation methodology of Table 4-6. This phenomenon is attributed to the treatment plant effluent of one municipality which is discharging untreated waste- water. The BODr loading of East St. Louis represents 11 million pounds per year or 44 percent of the totaT loading of 63 communities. Without the East St. Louis discharge, the annual BODr loadings attributed to CSO would be comparable to that of the wastewater plants. The annual suspended solids contribution of untreated CSO ranges from 7 to 13 times greater than that discharged from the wastewater treat- ment plants. This proportion is considered representative of the overflow contribution for all 132 plants. The BODr and suspended loadings associated with small combined sewer areas, communities on intermittent streams, and communities discharging to major tributaries are also of concern. The magnitude of CSO contributions 71 to 00 Q O _J ct r^ UJ 1 Od «:^ \— cu o 1 — 1— JD fd 00 1— CD ^ 1 — 1 Q C s- O) m :3 QJ ^^ >, M- 4- to LU JD Q- 1— ** 3 cn 3 e •r~ -D 03 O _J LO Q O CQ , O ft! OO Z3 C_) o o o o o ID CM o o o CM O i2^ o o o o o o o o o o c\i r^ o o o o o 00 «\ CM I o o o o o o o o o o CM CO 00 to r-H UO oo +-> +J E o o ^— o r^ -^i- o o o o o o o o o o o o o o Ln o o o o o o o o o o o o o O CD o o O CD O O 00 CO o o o o LT) O ■vi- cn cy> CM LO CM o o o o CO o CM O O O O O o o o o o o o o o o o o o o CO r^ 00 E o CO (/) O cu CO •r- cu >) +J .— -Q c c -a 3 o cu E •■- > E 4-> S- O 03 cu C_5 1 — I/) oo CO ■o E cu 03 +-> cu 03 S- O +J O CO +-> CO c OJ cu •r- +J +-> +-) E i 13 S_ E cu E +-> O c o o o o CO 03 o O-D I — CO E CO 03 cu cu •r- S_ •*-> +-> ■I— CO o o 03 o o o o o o o o o o o o o o o o C3^ O "^ oo o o o o o CO A IT) o o o o o o o o o o CM >>CU -M VO •r- CD s- CO o •I- c i~ 03 Q..E: +-> x: +-> s- •r- cu 3 4-> 03 CO cu cu s- •I- CD +-> •r- CO C S- 13 cu E -Q o o T3 -O -O -O cu cu cu cu »l •! •! •! 4-4-4-4- -(_) 4-> +-> +-> c c: E c cu cu cu cu -O -a T3 T3 CO CO CO 00 4-> cu cu cu cu +J 4-> +-> +-> 4- o (U E :3 CO CO CO 03 <— • CO +-> cri C c cu •r— CO cu S- cu o oo CO c_) cu cu >— -e 03 3 =3 E E E E o o o o CM -sj- 4- 4- o o 03 o r^ ^ Lf) CM r-i CM +-> +-> +J EEC cu cu cu CO C/1 CO cu cu cu S- s- s_ Cl Cl Cl OJ cu cu S- S- S- CO CO I/) cu Avg. Load per Event -1 -'^ -1 (Innnn fl fl > Level 3: Actual distribution of load within each storm (first flush, etc.) LB/HR ' Avg Loading Rate per Event ^l\^^r\ N A One Year Figure 4-4 TYPICAL DISTRIBUTION OF STORMWATER LOADINGS SOURCE: Reference 5, p. 22. n fluctuating impacts on the environment. The level of control required to protect the receiving stream may represent full treatment of peak load- ings or only treatment of average loadings depending upon site specific characteristics. 4.1.1 Rainfall Patterns To design for the control of intermittent CSO events requires an evaluation of the rainfall pattern and its impact upon CSO loadings. The hourly rainfall and frequency of occurrence pattern for Urbana was developed by Illinois State Water Survey (ISWS) in evaluating stormwater management. ISWS determined that Figure 4-5 was representative of the statewide pat- ,.12 12 tern. In analyzing the daily rainfall records, ISWS defined an event as a "dry period followed by more than 0.1 inch of rainfall in one day. For the Rockford and Quad Cities areas there are 42 such events a year and for the remainder of the state there are 47 events per year. Thus, Figure 4-5 illustrates the probability of various rainfall intensities, and this can be restated in terms of the number of rainfall events per year of a given magnitude. Table 4-8 summarizes the expected number of events per year for various rainfall intensities greater than 0.10 inches per hour. The average rainfall conditions are also of importance in determin- ing the level of protection afforded by Rule 602 treatment specifications and alternatives. Table 4-9 describes the mean rainfall per year and the number of days rainfall exceeds 0.01 inches for seven areas. Over 100 days per year there is precipitation exceeding 0.01 inch of accumu- lation in Illinois. Thus, from Tables 4-8 and 4-9 it appears there are approximately 53 days per year where rainfall depth is between 0.01 and 0.10 inch. The level of protection (or reduction in CSO) can be determined for alternative levels of CSO regulation by translating average and maximum rainfall events into runoff volumes requiring treatment. Utilizing the treatment efficiencies of Chapter 3 and the alternative sizes of treatment facilities, reductions in CSO can thus be estimated. 75 UJ 1.50 1.25 - 1.00 -> 0.75 — 0.50 — 0.25 — 0.2 0.5 1 2 5 10 20 30 40 50 60 70 80 PROBABILITY OF VALUE SHOWN BEING EQUALLED OR EXCEEDED 90 Figure 4-5 FREQUENCY OF HOURLY RAINFALL EVENTS SOURCE: lEPA, Urban Stormwater Management , Peoria, February, 1979 76 Table 4-8 RAINFALL FREQUENCY-INTENSITY PATTERN IN ILLINOIS Number of Events per Year Which Exceed Rainfall Specified Rainfall Intensity inches per hour Rockford/Quad Cities Remainder of State 0.75 1 1 0.50 3 3.5 0.25 13 14 0.15 26 29 0.10 36 40 SOURCE: Reference 12, p. 2-25 and 2-26. 77 Location Table 4-9 MEAN RAINFALL CHARACTERISTICS OF ILLINOIS COMMUNITIES Mean Number of Days Mean Inches of Rainfall With Rain > 0.01 Inches Per Year Alton 104 41.2 Champaign 112 37.0 Decatur 112 37.1 Joliet 120 33.8 Peoria 109 34.8 Springfield 112 34.8 Moline 110 32.8 SOURCE: Denmark, W. , "The Climate of Illinois," 1969, pp. 90-107. 78 4.5.2 Estimating CSO Pollutant Reductions To determine the present control efficiency of combined sewer over- flows as specified in Rule 602 and alternatives, it is necessary to relate rainfall events to surcharges in the sewer system. Depending upon the magnitude and duration of the storm event, the water volume to be handled in the combined sewer system varies greatly. To understand the difficulties in controlling combined sewer overflows, it is necessary to briefly describe the hydraulics of sewer systems. Rainfall events occur in a time interval known as the duration (D). Because there is a lag in the time rainfall reaches the ground and is discharged from a sewer system, the distribution of runoff volumes dis- charged varies with time and is different from the rainfall pattern. Figure 4-6 presents a typical discharge pattern in which the runoff reaches a peak flow at time, T , and then diminishes. Note the rainfall event of duration, D, may be completed before the discharge reaches a maximum value. The actual form of the discharge pattern (hydrograph) varies with rainfall patterns and other site specific characteristics. The quantity of water expected in a combined sewer system or storm water system depends upon the rainfall intensity, area drained, and the amount of rainfall which eventually runs off into the sewer system. This volume is the area under the curve of Figure 4-6. The most commonly used method of calculating the maximum rate of runoff is known as the "Rational 13 Method" and is described by the following equation: 1) Q = 0.75CiA* where A = drainage area, acres i = average rainfall intensity, in inches per hour C - runoff coefficient Q = maximum runoff rate in cubic feet second Note: *1.008 cfs = 1 inch rainfall applied at uniform rate for 1 hour to 1 acre 79 mm/hr 2.0 3,0 4.0 TIME IN HOURS iO 6j0 Figure 4-6 TYPICAL DISTRIBUTION OF RUNOFF DISCHARGE (HYDROGRAPH) SOURCE: Reference 13, p. 113. 80 This generalized equation uses average rainfall intensities, and it is considered an acceptable estimating technique for urban areas of less than 5 square miles or 3200 acres. The runoff coefficient, C, depends upon the infiltration, ground slope, ground cover, surface and depression storage, evaporation, previous precipitation, and other factors affecting the ultimate disposition of rainfall. Depending upon the land use, the value of C will vary. Table 4-10 summarizes some of the typical values of C. The runoff coefficient is, of course, higher for those areas where rainfall cannot soak into the ground but is collected on impervious sur- faces. Downtown areas and heavy industrial sites have runoff coefficients twice as large as residential areas. The value of the runoff coefficient would be expected to vary with seasonal conditions and with the deviation and intensity of the rainstorm. The average values of Table 4-10 represent typical levels associated with storms of five year to ten year frequencies. More frequent storms with less intensity would require lower coefficient values. The maximum flow rate, Q, described in equation 1 represents the design processing rate of the sewer system and treatment facilities. To determine the volume of water to be handled or treated, the peak flow rate and the time of concentration are needed. The time of concentration, T , represents the travel time from the farthest point in the drainage area to the inlet to the treatment facilities. This time depends upon the time required for the runoff to reach the sewer inlet plus the time of flow in the sewer system. For the purposes of estimating the runoff volumes generated during design storms, the time of concentration is assumed to be less than or equal to the storm duration. Site studies conducted by the U.S. Environmental Protection Agency were examined to obtain an estimate of the expected characteristics of small and intermediate sized communities in Illinois. Bucyrus, Ohio is a town which has 100 percent combined sewers, a flat landscape, a drainage ( 6 area of 2,599 acres, and annual runoff of 13.5 inches. The time of con- centration for Bucyrus was 0.52 hours. 81 Table 4-10 TYPICAL RUNOFF COEFFICIENTS Description of Area Runoff Coefficients Business Downtown 0.70 to 0.95 Neighborhood 0.50 to 0.70 Residential Single family 0.30 to 0.50 Multi -family, detached 0.40 to 0.60 Residential, suburban 0.25 to 0.40 Apartment 0.50 to 0.70 Industrial Light 0.50 to 0.80 Heavy 0.60 to 0.90 Parks 0.10 to 0.25 Unimproved 0.10 to 0.30 SOURCE: Reference 13, p. 111. 82 For those towns where combined sewers were only a portion of the system, the time of concentration varied from one to five hours. In evaluating the runoff volumes generated with varying storm intensities, a storm duration of one hour was considered greater than or equal to the time of concentration. The estimating of CSO control levels depends upon the size of facil- ities and the intensity and duration of rainfall events on an annual basis. The first flush treatment reduces the high concentration of pollutants prior to initiation of maximum CSO flows. Figure 4-7 depicts the typical pattern of flow and pollutant concentration resulting from a rainfall event. In a short interval (less than an hour) pollutant concentrations may peak and then decrease. Site specific characteristics can alter this pattern but it is considered a typical condition. Flows usually peak at a later time than pollutant levels. The Illinois criteria specify full secondary treatment of first flush flows. Since this volume is unknown for most Illinois communities, an estimation rule of 2.5 times dry weather flow is utilized. This may understate actual requirements but provides a consistent calculating technique. Table 4-11 presents the distribution of treatment capacities according to rainfall intensity. This variation in treatment capability is attributed to the difference between dry weather flows and the size of the combined sewer area. Dry weather flows reflect the popu- lation being served regardless of their density (persons per acre). Com- bined sewers collect runoff from the area served, and thus the peak flows are dependent upon the runoff area. Two communities with similar dry weather flows may have significantly different wet weather flow character- istics. Table 4-11 demonstrates the range in treatment capacity which does occur. Primary treatment capacity of 10 times the dry weather flow can also be represented as the maximum processing rate of overflows. This differs from first flush treatment because the treatment of first flush requires a storage volume equivalent to the estimated first flush volume. Primary treatment capacity will process storm flows at a rate 10 times r 1400 1300 1200 1100 iOOO »oo 000 700 M CO 600 »- 900 400 300 200 100 70r E I O 70 60 20 -10 «£ c SO 20 > u. Z u. LU 40 S 1.6 1- 2 z 3 1 a -1 < 30 «.2 U. z < 2* 2.4 Time E 1400 IMO ItOO HOC lopo •CO E •oo 700 1 O •00 MO 400 • JOG ■ 20C 100 ,., . 70 60 C SO 40 uj .30 < .20 < 17 IS . 19 20 5-7-69 22 23 24 01 02 03 04 03 5-8-69 • .lO J o Time Figure 4-7 TYPICAL DISTRIBUTION OF MAXIMUM POLLUTANT CONCENTRATIONS AND FLOW SOURCE: Reference 6, pp. 98-99. 84 I O) j3 o o »— I I— o 00 o Q_ LU UJ >- 31 I— oo c/l 0) >> • r— S- 4-> fO •1— E r— •r— ftJ s-o Q.Q. • 1— +-> O +J 2: o (T3 s- OJ M- Q. s- O Sl h- S- o dJ • »— JD x: c -Q fO JZ r— o CO 1 13 m -C 1 — 14- o Ll_ c •r— •r— JZ +-> fO 3 CO Cd S- CO 'r— .^ cu u_ 4J • r" •»^ 4J 1 — 2 • ^ t—^ 1 — <: -o to cu Q.4-> ■t-> •1— fO fO u s- S_ E O) o :z X3 +-> r— E 00 o 3 > (T3 4->n3 4- • 1— e 5 -c ■r* CO fC -o 3 a: O) r— ■t-> U- <+- (O o •1- +J O (/) CO O S- O) (A -i- .c lO Ll_ o«=c c «\ s- •»-> 3 c O o) n: > UJ s- O) 1 — Q. t— fO CO **- 0) c x: • r— u fO c OC 1— 1 CO ro CO oo O C\J r>- r-H cvj c\j oo oo C\J en r^ oo r-- oo o c\j m uo VD CTi CO oo LTO LD (JD CO CO 1^ CO CO CO VX3 CO CO V£> CO 00 CO CM C\J O) -M to i~ c r— o ^— • ^ *♦- 3 C 1 JD •.- CO •r- fO •<- • s_ S- T3 (/) ■t-> O) CO >» 00 •1— •1— ^— ' "r— +-> ■o J- ^ .f— Z3 4-> CO CO o C •r- .C " Ol x: S- +-> -M CO S- +-> m O) OJ zr>sz r^ S c: 4-> CO • r— fO • >> >^ OJ o s- i_ •3. -o (T3 c > >> o a» S- .a ■(-> -0 -O -!-> fO O) OJ CO I/) O x: fO X> E O •r— CO CO +-> 4-> 0) • I— (T3 E ir> O) JZ • S- +J oo CVJ -M 3 .— M- O 1—4 «4- O +J • 4-> >, I/O fO CO -l-> c CU S- -r- 2 >» s- •r- O o ■4-> 4-> l+- (tJ 4-> •r- Q. u -E rO CO (C -M +-> U CO Q. ■r~ (O CO S cu 4- C en O 2 "O fO +-> OJ s- >> c +J +-> o 4-> O) (T3 +-> • 1 — E CO •I- CO 1^ -i-> vo O ■1 — fO o -c ^ O) *♦- I/) CO fO s_ 00 3 +-> 03 1— cn CO 4- 4-J >, (C CO CO E •-- 4- s_ OJ ■r- ^— c: -r- S- S_ -r- •r- li- Q. Q.JD re O) fO s- M CO Q) -f- 3 •.- OJ -C 1— JD n- s- O -r- •1 — •.- CL C -(-> S_ +-> ZD S_ 03 JD CO O 85 the dry weather flow rate. This means a dry weather flow of 1 MGD has a storage capacity of 2.5 million gallons for first flush but the hourly rate of primary treatment is ten times 1 MGD then divided by 24 hours per day or 0.42 million gallons per hour . Thus, the hourly rainfall inten- sity which can be handled in primary treatment facilities is much lower than that indicated for first flush. The reduction of pollutants in CSO is therefore based upon the ability of a facility to treat a variety of storm events. To calculate the annual removal, the distribution and magnitude of rainfall events is compared to available treatment capacity. The following procedure is utilized to determine the pollutant removals attributed to first flush treatment and extended flow treatment on an annual basis. A. The volume of first flush receiving treatment during any storm event is assumed to be that volume discharged in the first hour's precipitation. B. The total volume of runoff for any rainfall event is determined from the following two equations: Q = ciA V = Q(jg^) x3600(^) X 7.5(f|-l-) X 10"^ x t^^Chr) where Q = velocity of flow in cfs c = runoff coefficient of 0.59 i = rainfall rate, inches per hour A = area of combined sewers, acres V = volume to be treated, MG trj = duration of rainfall event, hr C. The volume of first flush may be calculated by assuming a particular distribution of runoff discharge. In the appendix the general calculation method is decribed, and this method results in a first flush volume of 0.37 of the total volume of the first hour's rainfall. First flush volume = 0.37V 86 where D. The annual volume of first flush flows requiring treatment is a function of rainfall intensity and their duration. Utilizing Table 4-8 and adjusting for an annual rainfall of 36 inches per year, the duration of a storm event is assumed to be 3.2 hours. The following schedule of rainfall events is utilized to project volumes treated. Number of Average rainfall intensity. Volume of rainfall events inches per hour f or 3.2 hours, inche s 1 0.75 2.4 3 0.62 2.0 9 0.37 1.2 13 0.20 0.6 10 0.125 0.4 20 0.075 0.2 E. Annual Volume of First Flush Treatment = IV N V = volume in MGD for rainfall intensity of "x" inches per hour A N = number of events of rainfall "x" inches per hour A F. Annual reduction in BODj. and suspended solids loadings associated with first flush based on typical concentrations and secondary treatment efficiency of 85% for BODc and 80% for suspended solids. lbs BOD removed = [5;v N ] [(186 mg/5, BOD ) x 0.85][8.34] A A D lbs suspended solids removed = [^ V N ][(520 mg/il SS) x 0.80][8.34] A A Primary treatment efficiencies are based upon the excess first flush flow not stored and treatment of flows extending beyond the first hour. The rate of treatment is determined by capacity specified as ten times, five times, and two times the dry weather flow. Table 4-11 presents the distri- bution of communities capable of treating first flush and primary flows generated with varying rainfall intensities utilizing Rule 602 as a design criteria. This distribution represents 63 communities for which sufficient design information is available. The methodology for calculating primary Q7 treatment removal is summarized as the following: A. The volume receiving primary treatment represents excess first flush flow plus maximum design capacity rate for 3.89 hours. B. The volume of runoff receiving primary treatment is determined from the following equation: where where V = 3.89 ciA 3.89 = hours of discharge at design rate (see Appendix for derivation V = volume receiving primary treatment °^ design number) c = runoff coefficient of 0.59 A = area of runoff, acres 1 = inches of rainfall per hour that can be treated by treatment plant of volume 10 times, 5 times, or 2x the dry weather flow, "i" is calculated using the primary capacity in MGD as the maximum rate handled. C. The annual volume of flow receiving primary treatment is a function of rainfall intensity, duration, and frequency of occurrence. The distribution indicated in item (c) of the first flush methodology is the same for primary treatment. D. Annual volume of receiving primary treatment = \^ W V = volume in MGD for rainfall of intensity of "x" inches per hour N = number of events of rainfall "x" inches per hour. X E. Annual reduction in BOD^. and suspended sol ids loadings associated with primary treatment are based on typical concentrations of 49 mg/£ of BODg and 166 mgA of suspended solids and treatment removal efficiencies of 25 percent for BODr and 30 percent for suspended solids. Concentrations from Table 4-2. lbs BOD removal = [^ V N ][49 mg/£ BOD x 0.25][8.34] XX D lbs suspended solids removed = [J! V N^][166 mg/£ SS x 0.30][8.34] X X 88 4.5.3 Pollutant Reductions of Various CSO Levels of Control Utilizing these estimating methodologies for first flush and primary treatment, the total annual pounds of BOD^ and suspended solids removed are calculated. Table 4-12 summarizes the loading removals for Rule 602 and alternative levels of control. The values shown in Table 4-12 are based upon 63 communities which are considered representative of the 132 affected municipalities. Treatment of first flush represents removal of 12 to 39 percent of the 600^. and 6 to 12 percent of the suspended solids loading attributed to CSO. Primary treatment of 10 times the dry weather flow reduces BOD^. and suspended solids loadings by 2 to 5 and 1 to 2 percent of the uncontrolled loadings, respectively. These values were estimated based upon the Rational Method for calculating peak flows, duration of discharge, and volume treated. To be consistent, the uncon- trolled CSO loadings utilized for comparative purposes were developed utilizing the method described in Section 4.5.2 and not Table 4-6. As shown in Table 4-12, reducing the size requirement for primary treatment reduces the removals for BODj. and SS approximately proportion- ately. First flush treatment removes over seven times the BODg and nearly five times the SS that primary treatment of ten times the dry weather flow removes. The other control alternative presented in Table 4-12 is sewer flush- ing for communities with priority numbers greater than 806. A range of removal, from 15 to 40% of the uncontrolled CSO loadings was assumed for this practice. The removal of BOD^. andSS which would be attained if Rule 602 were implemented for these 25 communities would be 1,900,000 and 5,500,000 pounds per year, respectively. 4. 6 Environmental Effects of CSO Controls 4.6.1 Removal of Organic Pollutants In Table 4-12 the estimated reduction in organic loading was presented for a variety of control levels. First flush treatment resulted in the greatest removal of BOD^ and suspended solids loadings while primary 89 Table 4-12 POLLUTANT REDUCTION ASSOCIATED WITH VARIOUS CONTROL LEVELS rnntrni I pv/pI Pounds of BOD Pounds of Suspended LonLroi Level Removed per ydar Solids Removed Per Year Storage and secondary treatment of first 7,100,000 19,500,000 flush^ Primary treatment of 10 times dry weather 1,000,000 4,100,000 flows^ Primary treatment of 5 times dry 520,000 2,100,000 weather flow^ Primary treatment of 2 times dry weather 180,000 710,000 flow^ Sewer flushing for 3,300,000- 10,000,000- communities with 8,800,000 ' 26,000,000 priority number , greater than 806 Total uncontrolled 18,200,000- 169,000,000- CSO loadings^'^ 56,800,000 340,000,000 Notes: a) Values represent 63 of the 132 affected communities. b) Values represent 25 of 46 affected communities. c) For comparative purposes the BODj- removed of 56.8 million pounds and the SS of 169 million pounds should be utilized, as these values were derived using the same method as the other control levels. The other set of values was derived utilizing the equations in Table 4-6. 90 treatment produced an incremental improvement. The effects on water quality associated with such removals depends considerably upon the nature of the receiving stream. Combined sewer overflow events are generally wet weather events which means the receiving stream is flowing at the time of discharge. The concentration of organic material and magnitude of discharge determine the degree of assimilative capacity required by the stream to prevent severe oxygen depletion. Adding CSO controls improves the level of protection of the stream since overflows will continue to occur only for more intense rainfall events. At these higher intensity storm events the stream volume has also increased, thus reducing the impact of the organic contribution. Table 4-13 presents the distribution of conmunities which could treat discharges associated with various rainfall events. This distribution is based upon implementation of Rule 602 design criteria. Clearly, as the intensity of storm events increases, the capacity required for treatment increases. To treat the flows generated by a 0.75 inch per hour rainfall (a once per year event) would require additional storage treatment capacity for 30 communities and additional primary treatment capacity for 60 commun- ities. Determining the appropriate level of protection depends upon stream size and control costs. There is a specific tradeoff between the level of protection (number of rainfall events for which complete treatment is assured) and the costs of treatment. To determine the level of protection afforded streams according to Rule 602 and other control alternatives, the annual reduction in BOD^ and suspended solids are first calculated. Table 4-12 described these loading reductions. On an annual basis Rule 602 results in a minimum removal of 14 percent of BOD^ and 14 percent of suspended solids attributed to CSO. Since the water quality impacts upon a stream are also dependent upon the number of overflow events per year, the data in Table 4-13 are used to develop a description of the level of protection. This level of protection is identified in terms of the number of rainfall events per year which receive complete secondary or primary t^^eatment. First 91 oo LlJ o en o o o o LlJ ro 1 I— ^ ^ -c l- -M 4-> (O C (T3 2 E (U O) fl3 E 3 .— +J si 4-> Ll_ C Q. (O >^ OJ OJ S- E S- Q -M H- »a OJ S- 1— X s_ , — LO OJ 1 — >1 XI 3 $- ■t-> -M Ll_ fO C fO B E O) CD CT) E 3 r- C z. 4-> Ll_ • r— a. ro >, -0 cu S-. • 1— i- Q > 1— s_ D- co X > J= • r— S- +-> 4-> c fO C (O 2 :3 E OJ O) E E 3 .— E S- +J Ll. D. (O >) S. Q <<- H- s- ■o ^ O) C 4/1 +-> JD 03 3 c: E r- OJ 3 c i- QJ (U > JD LU to C QJ 2 _J O cu I/) (_) u E o zs I— +-> ^ 1— S-. TO C . — <4- cu -C to C >- ■!-> I— O 03 S- »— q: cu Q. +-> r— C r— CU CO E *+- i- 4-> C :3 fO -r- > \— +-> s- CO •r— cu M- TO t/1 CL c "D cu CO >, CU -l-> cu 4-> CO c -C ;- CO »— < CU c TO S- »— 1 CL Q. TO X C_3 LU CO CT> (X) (^ ro CO CM nc\Jc\jmcT>rOrocvj UD Ln CM r— I U3 LO o vx) cr> CM i-H CM CO CO n ro ro ro ro ro CTt U3 in Ln LD CO CM 00 CO 00 y£i t— 1 r—\ ^ CO UD r^ i-H CO ^ tn UD r^ CX) cr> en cr> CO o LO o o o. vl o I o o o I ro o CD I LO o LO 1—1 o o LO CM O LO 10 o I O LO VD t— I CM o I LO o LO ^1 cu J3 ro 1 — •n" (T3 CO • n CM 2 UD c CU •r— ■M 3 ra q; E s- -C +J 4- c S •r— cu 4-> CJ C c: CU TO •r~ • r— a , • r- CL 4- E H- 3 to E cu •1 — S- CU -D sz CU s 4-> TO CO CU cu s- +-> 4-> •1 — CO c s 3 1 <+I u ) — 1 — • CO TO UD CO 4- c: TO CU ,— E TO 4-> ■»-> E +-> TO C CU S- +-> -0 CU ~~ CO ~" fO 3 cS JL. TO O) +-> c 92 flush treatment of all storms occurring with an annual frequency (97 events per year) is possible for 42 percent of the 63 dischargers combined. All 63 dischargers can treat fully the first flush of at least 61 of 97 events per year. The remaining flows from 36 events receive partial secondary and primary treatment. It should be noted that Rule 602 specifies treat- ment of all first flush flows, and it appears some communities would require treatment capacity greater than the estimated volume of 2.5 times the dry weather flow. Primary treatment capacity of ten times the dry weather flow provides a lower level of protection in that all 63 dischargers provide complete sedimentation for only 13 events per year, and only 3 can treat all annual rainfall events. Only 30 percent or 19 of the communities could fully treat 61 of the 97 rainfall events per year. Higher intensity storm events receive a partial level of treatment, varying from 1 to 99 percent, depend- ing upon the individual discharger. For a1 1 dischargers to treat 61 of 97 events per year would require a primary treatment capacity of 70 times the dry weather flow for at least seven dischargers. This capacity rate would decrease for other facilities. For all dischargers to fully treat all annual events would require a maximum of 750 times the dry weather flow. Reduction of the primary treatment capacity to five times or two times the dry weather flow reduces the level of protection to less than 13 events per year receiving full treatment. At five times the dry weather flow only 14 percent of the dischargers can even fully treat 61 of 97 rainfall events per year. This percentage drops to 5 percent for a capacity of two times the dry weather flow. Thus, the level of pro- tection afforded by such control alternatives is minimal. The actual design of first flush and primary treatment system may require greater capacities than those assumed herein. To assure all first flush volumes are treated may require higher costs than those presented in Chapter 3. Since Rule 602 requires complete first flush treatment, the actual level of protection would be higher than presented in Table 4-13. Table 4-13, however, depicts the varying level of treatment which may occur as a result of Rule 602. 93 4.6.2 Disinfection of Combined Sewer Overflows 4.6.2.1 Health Implications Rule 602 presently specifies disinfection of all excess flows receiving primary treatment. The simplest and most inexpensive disin- fection method to date has been considered to be chlorination. The purpose of disinfection is to reduce the number of infectious agents (bacteria, virus, and parasites) discharged to the receiving stream. The concern with untreated CSO relates primarily to health effects associated with waterborne disease outbreaks. Disinfection of CSO flows is intended to reduce the risk of disease for surface water users. The type of pathogens present in untreated or raw sewage and the associated disease are listed in Table 4-l4. Disease incidence is deter- mined by a number of factors including the dose level (number of organisms present), ingestion of water, and other physical factors. This dose level varies for each pathogen and has been primarily determined in laboratory situations. In receiving waters, "clumps" of solids make it difficult 14 to determine the actual level present; however. Table 4-15 depicts the relative difference in density required for dose level response of these pathogenic organisms. The most common forms of organisms resulting in disease are the Salmonella and Shigella. The number of cases reported between 1961 and 1974 were summarized in Table 4-l4. These may be an under- statement, however, since the Center for Disease Control indicates this 15 may represent only 5 percent of the infected population. Reduction of microorganisms typically occurs via a natural die- off phenomenon and during the treatment process of sewage. The natural die-off of some infectious agents are depicted in Table 4-16. These specific agents have half-lives of 12 to 48 hours in surface waters, and the time 15 of removal of 99.9 percent of the agents varies from 5 to 20 days. There is some controversy regarding the die-off and regrowth of other micro- organisms which are utilized as indicators of pathogenic risk. Fecal and total coliform bacteria are presently utilized as indicators of patho- genic presence. Their value as indicators is currently suspect, »•'■'»•'• and their importance with regard to CSO overflows is to depict the rela- tive strength of CSO discharges versus treated effluents and chlorinated effluents. 94 Table 4-14 SUMMARY INFORMATION ON REPORTED WATERBORNE DISEASE IN THE UNITED STATES Wastewater constituent Disease incidents, 1961-1974 Reported no. Reported no. Resulting disease of outbreaks of cases Reported untreated wastewater concentration , No./lOO mL Indicator organisms Total coliforms NA Fecal coliforms NA NA NA NA NA 10- lof Bacteria Shigella sp SalmoneTla typhi Salmonella sp ^ Escherichia coli Virus NS Hepatitis virus A Parasites Entamoeba h istolytica Giardia lamblia Miscellaneous NS Chemical agents Shigellosis Typhoid fever Salmonellosis NS Hepatitis A Amoebiasis Giardiasis Gastroenteritis ^ Chemical poisoning 32 18 11 4b NA 43 15^ 85 4,413 326 16,743 188 NA 1,254 39 5,303^ 34,538 474' ND 10^ to 4x10^ 600 ND 700 to 1,900 4x10-1 ND ND ND Note: NA = not applicable; a. Excludes S. typhi . b. c. d. e. ND = no data; NS = not specified, None reported during 1971-1974. Incomplete reporting for major incidents only. May include other disease previously reported. For the time interval 1971-1974. SOURCE: Reference 15, p. 9. 95 Table 4-15 DOSE RESPONSE FOR SELECTED ENTERIC MICROORGANISMS Microorganism No. per dose Shigella sp, S^ typhi Salmonella sp. (not S^ typhi ) E. coli Vibrio cholerae G. Lamblia Virus lO'^-lO-' 10*-10'' io6-io9 lO^-iolO lO^-lO^ 10^-10^ (infection without illness) Not )cnown a. Needed to produce illness in 25 to 75% of persons ta)cing dose. SOURCE: Reference 15, p. 17 Table 4-16 SURVIVAL OF INFECTIOUS AGENTS IN SURFACE WATERS — Time for 99. 9% Removal after Infectious agent removal, d Half-life, h 2 d, % E. coli 5-7 12-17 86-94 S. fecalis 8-18 19-43 54-83 Enterobacter aerogenes 8-18 19-43 54-83 Echo 7 7-16 17-39 59-86 Echo 12 5-12 12-29 68-94 CoxsacJcie A9 l8 19 >83 Polio I 13-20 31-48 50-65 SOURCE: Reference 15, p. 27. 96 In addition to natural removal of organisms, treatment processes also eliminate pathogens. Each additional treatment process removes an incremental amount of organisms, and thus, each reduction decreases the probability of disease incidence. Table 4-17 presents the removal effi- ciencies of primary and secondary treatment processes on various enteric (of or pertaining to the alimentary canal-mouth to anus) microorganisms. Primary treatment alone produces a 10 to 15 percent removal, depending upon the microorganisms. Shigella and Salmonella are typically reduced 15 percent by primary treatment processes. U.S. EPA demonstration projects regarding disinfection of combined sewer overflows indicated the following three methods to reduce bac- 21 terial levels to state effluent levels: a) Chlorine (CI 2) dosage of 25 mg/£ with two minute retention time. b) CIO2 dosage of 12 mg/£ with two minute retention time c) Two stage addition of 2 mg/£ of CIO2 followed by 8 mg/£ of CI 2 in 15 to 30 seconds. The disinfectant levels indicated above represented concentrations necessary to maintain 200 fecal col i form per 100 ml in first flush. Approximately 50 percent lower concentration was adequate for handling diluted overflows. Variation in fecal coliform levels occurred due to erratic flow conditions and equipment performance. Figure 4-8 pre- sents some ofthe typical results obtained during actual operation of pilot units. Regression analysis of the factors affecting the logkill of bacteria resulted in the following form: logkill : KiC^2ejK335K,p^K5^QKepH where C = disinfectant concentration, mg/il SS = SS concentration, mg/l FC = influent level of fecal coliform, counts/100 ml pH = pH GT = mixing intensity x detention time in zone of influence Ki, K2, K3, Kh, K5, Ke = constants 97 Contact time was held constant at one minute for the regression analysis, The results of the analysis indicated that the disinfectant concentra- tion and mixing intensity were the most important factors in reducing bacterial levels. These pilot results demonstrated that CSO can be disinfected with high-rate techniques to levels consistent with 200 fecal col i form per 100 milliliters. Although the presence of viruses was acknowledged and attempts were made for collection and treatment of viruses, the "low levels and 21 random appearances of wild viruses" confounded evaluation. The U.S. EPA investigation concluded that the unknown nature of virus populations in CSO and the limitations on detection made it impossible to meaning- fully evaluate the disinfection effectiveness for wild viruses in CSO. The U.S. EPA study of "seeded" viral kill effectiveness concluded that a minimum dose of 12 mg/£ of chlorine (CI 2) or 8 mg/£ of CIO2 is needed. For purposes of evaluating the typical reduction of microorganisms obtained, the concentrations of microorganisms depicted in Table 4-14 are utilized with general removal efficiencies of primary treatment with and without chlorination. These resulting levels are compared to general dose levels of Table 4-15. It must be considered in evalua- ting these values that there is considerable fluctuation in literature reports regarding chlorination, microorganisms populations, and dose levels. The values of Table 4-18 are considered to represent an uncer- tainty of ±50 percent. Table 4-18 demonstrates the difference in organism density due to chlorination of CSO. The quantity of water which would be imbibed to induce disease varies from 2 to 10** times as much if primary treat- ment is utilized with chlorination of CSO. The range is dependent upon the infectious agent considered and the effectiveness of chlorination. Thus, the level of risk of disease incidence is 2 to 10,000 times greater with only primary treatment. The health impact of combined sewer overflows depends upon the receiving stream and its associated uses. Five combined sewer 98 I O) to LU to 40 UJ o o o. LU I— < LU 00 00 O o uu o z o Q i 8, 3 9 -H to 2 I J J HO an m I I ^8 J 2 2 5 i I i S5 c ? o -« <-< s -<• «• "^ o • J- h .• .1 - u «4 H 3 ?JSi •< > T • • • o « o X > c o o -< 2 !l S c » o u I I 4J r hi & >t • U J , «« 5 •i e 8 3 • ? \ 3 1 > >• S • W s c 3 2 o 4 M ki • • 2 «« *> m > • « r 1 1 a :l un o c cu s- O) 4- OJ UJ o or o 99 I LlJ o Q QJ CO I LU 00 r— O J2 or 03 O OO LU cu «=c o Q OO »< s- S- C O) Ol Q. -l-> •1— 't- -M to c^ < (O E E C (O r-l cu .— C71 _l ^ S- CM o J E E CO — I— -r- O OJ CO > >, 03 <— I _1 03 5- E O •r— s- Q. c S- a; Q. -M fO fO CO c^ s_ E E 00 -l-> CO c ■r- OJ c u 03 I— 1 c: cn s- o o o o CM CO o CO o o +-> o o • T— I I 1 — I o o CM r^ I o CO C\J CM I o X X OJ CO CO CM o X I LO cr> o o CTl r o o Ln c a» 13 4-> •r- 4-) 00 C s- a> +-> 03 fO s il cu CU 4-> -fJ CO 03 03 3 CO X en X CO X X o o o o Cl. CO Q. CO 03 r— 03 1 r — CU 1 — c CU a E •r— r— .c (O 00 00 CO OJ 4-> 'r- CO 03 S- 03 03 CJ •r— 4-> >t| O +-> 00 03 CU O E 03 I LO CM CO 00 cu -a cu cu -C cu 4-> c I/) CO fO • E CO CU »— 1 • r— E 1 C 03 •^ 03 CO cu S- cu r— x: -Q +J 03 1— cu JD cu ja -l-> -0 CU E 3 T3 CO c CU 03 E JD cu 3 sz CO 10 +-> t/) f — 03 03 1/1 > +-> • O) c cu S- E cu CO 03 Cl. CD c (U c •r- cu S- •r- 4-> E J^ 03 +J +-> cu c c s- CO O) +-> CL c a CO • c >> cu t/1 03 S- S- s- ■«-> u 03 cu 03 E cu Q. ■0 •r— CO 00 i_ l+- C_) D_ Q z: o 100 municipalities are less than 20 miles upstream of public water supply intakes. Pontiac, Momence, Alton, Kinkaid, and Rosiclare all have over- flows within 20 miles of intakes. Alton is located on the Mississippi River, and Rosiclare discharges to the Ohio River. In these two cases the volume of the receiving stream minimizes the CSO impact. For the other three water supplies, chlorination of the intake water would be necessary. The half-life of infectious agents described in Table 4-16 indicates that 99.9 percent removal may take 5 to 20 days, depending upon the type of infectious agent. Thus, the increased potential health risk is limited to a 20 day period following a combined sewer overflow. For other streams of general use designation, swimming would be the major use impacted by CSO. Utilizing a 20 mile upstream criteria (based upon lEPA's regulatory proposal R77-12), there are six municipalities which may have a CSO impacting a beach area. Elgin, Yorkville, Aurora, Algonquin, Dixon, and Sterling have combined sewer systems which dis- charge to the Fox River or the Rock River. Recreational areas are desig- nated on these waterways for swimming purposes. The increased risk associated with the discontinuation of CSO chlorination is illustrated by the following example. The quantity of water which must be imbibed to cause illness in 25 to 75 percent of all people drinking the water will change from 3,000,000 milliliters to 300 milliters (based on Salmonella as agent and prior to dilution and die-off in the receiving stream)- Thus, for beach sites located downstream of combined sewer communities, there is an increased health risk, which warrants concern. 4.6.2.2 Adverse Effects of Chlorination Although health risks represent a positive factor for chlorination, there are adverse environmental effects associated with residual chlorine and associated compounds in the receiving stream. There is a great body of literature established regarding the effects of chlorine, and the general results will be summarized briefly to indicate the environmental concerns. 101 The environmental consequences associated with wastewater chlorina- tion practices are the hazardous effects it poses to invertebrate and vertebrate freshwater organisms, and the formation of halogenated organic compounds that are suspected of being toxic to man. The impact upon freshwater organisms depends primarily upon the concentration of chlorine that is released with wastewater effluent. CSO discharges are chlorinated with doses of 7 to 25 mg/£, and the residuals may be greater than 0.5 mg/(l. Generally, at low chlorine concentrations freshwater organisms will exhibit an avoidance response. As chlorine concentrations increase, reproductive success will decline, and at still higher concentrations the species diversity of vertebrate and invertebrate organisms will be reduced to due to the fact that only the heartiest of ingested parasites and viruses could survive. Lethal dose concentrations and concentrations at which reproduction is interrupted varies from one species to another. J. W. Arthur, in a study on the effects of chlorinated secondary wastewater effluent on the reproduction of fathead minnows, Daphnia magna , and the scud Gammarus pseudolimnaeus , found D. magna to be the more sensitive invertebrate species and died at a total residual 19 concentration (TRC) of 0.014 mg/Jl. Successful reproduction occurred below 0.003 mg/il, and scud reproduction was reduced at concentrations above approximately 0.012 iT|g/£. No effect on any life cycle stage, including reproduction, of the fathead minnow was observed at a concentration of 0.014 mg/il; adverse effects did occur at 0.042 mg/l. In a study conducted by the Michigan Department of Natural Resources, the effects of wastewater chlorination on frei^hwciter fish became apparent. Caged fish were placed in several receiving streams below wastewater dis- 20 charges. Fifty percent of the rainbow trout died within 96 hours at total residual concentrations (TRC) of 0.14 to 0.29 mg/£; some fish died as far as 0.8 mile below the outfall. These same discharges were studied when chlorination was temporarily interrupted and no mortality was observed. 102 3 In another study by Tsai , the effects on fish of 156 wastewater treatment plants in Maryland, Northern Virginia, and Southern Pennsylvania were investigated. All the plants discharged chlorinated municipal wastes into small streams containing fish. In most of the plants in Maryland and Virginia 0.5 to 2.0 mg/£ is the TRC maintained on the effluents. Pennsylvania requires 0.5 mg/il in effluents prior to discharge to natural surface wastes. Tsai studied principally fish, but observed typically a clean bottom without living organisms in the area immediately below the chlorinated outfalls. Unchlorinated discharger areas were typically characterized by abundant growths of wastewater fungi. No fish were found in water with a TRC above 0.37 mg/Jl, and the species diversity index reached zero at 0.25 mg/Jl. A 50 percent reduction in species diversity index occurred at 0.1 mg/£. The effects of residual chlorine upon aquatic life are important for concentrations greater than 0.01 mg/l TRC. When combined sewer overflows are chlorinated, the residual chlorine concentration would vary according to the organic composition and concentration. It should be considered that overflow events occur when maximum mixing volumes are available in the stream, which would minimize adverse effects. 103 To characterize the variety of combined sewer problems which exist and the extent of available water quality information, five site specific examples are described. Casey, Charleston, East St. Louis, Georgetown, and Peoria present a range of costs and water quality information. These examples present the best available water quality information regarding CSO impacts. Funding of CSO control projects is based upon information addressing the quality of CSO. No extensive field program or lEPA assessment is provided of the duration or magnitude of CSO effects upon water quality for downstream uses. Also, there is no attempt to factor in non-point source impacts as they contribute to poor water quality. As indicated in these summaries, there are proposed water quality monitoring programs which may provide additional insights. These projects, however, do not address downstream water quality or the duration of CSO impacts. The time and cost of a detailed monitoring program has limited the quantity of available water quality data. Most CSO amend- ments require one to two years for results to be reported, and thus, although studies are underway, little data are now accessible. Table 4-19 summarizes the characteristics of the site specific examples described in the following sections. The economic and water quality impact appears to be the function of so many variables that no simple decision rule can be utilized to predict effects. 4.7.1 Description of the Site Characteristics of Casey Casey is a small community of 2800 people located in Clark County. The receiving stream is the Quarry Branch of the North Fork of the Embarras River, and this stream has a seven day ten year low flow of "0." The 104 oo UJ X UJ o Q- 1—1 00 «* UJ t- o r M •r- (V VO r^ O vt o o ^ r— > cn «\ .—1 LT) vo ro O) CO 1 •!— ^ o o yD «« cr> • ro Q. t— 1 .-. q: CSJ r^ C\J oo .—1 vo r— 1 i>0- c 5 e o o 4-> •r— s- o O .-I o o o o o o o o o uo ^ Ln o o o CVJ o 3 O •1— _J Q. Q. +-> to OO cn to o (JD •r- S- o +J r-H to O) o to #\ to > " ftJ o •r— "1 — UD r^ UJ r^ s: q: "d- U3 o o o o *N o o o •* o CO o o OO o #« o CJ " o o r>. r«- CsJ r. oo • T—t C^0 oo (O to s- O) o CQ r— o -^ s- un C O) fO •% s o) -E O O O •— 1 O O O O I ^ •> O •> O .— I LD to •^ 00 ix) ) o .d S- fO to oo s- J3 (T3 « o E O oo z UJ o o o o o o o •^ o o 00 o r^ ^ •> •> <>0- OJ ,— I o o "^ OJ • oo .—I -faO- &« TD > S- to Q ■a O) +-> E s c O) o O) •1— S- -E ch to o 0) c C2. s_ -o to •1 — -o 03 O) 3 > a» s O) > o •1 — c o S- >> o -E E a; >> E (0 o XI <^ -faO- S- O) S- O) dj E s- <^ ■*-> ** OO to »+- O o to 4-> LT) OO -l-> c o O) o to Q to o CD •^ CD M- o o O + O •r— c 2 E 03 O o CO u 4-> • r— o 03 +-> 1 — Q (tJ > O) c s- 03 1 — I/) O 1 — r— • 1 — *4^ S- fO -a QQ 03 c 3 c O) T3 E fO ■t-> E (U E ■»-> (O O) S- +J o c/> o to +-> E a> to cu s- Q. (U &- «o •r— • s- S- o fO OJ O) D- >) 5^ s- J3 0) CL -o O) to > >> o , O ja to (U -a cn E 03 3 S O O) Q. to fO cu -M O 105 4.7.1.1 Planning Status of Community Casey has received a Step 3 grant for construction of a storm basin to contain combined sewer overflows. An analysis of overflows versus rainfall events was utilized to size the storm basin. 4.7.1.2 CSO Loading Characteristics Sixteen rainfall events which occurred over a two month, period were analyzed for overflow characteristics. Only six rainfall events resulted in overflows, and these overflows are summarized below: Rainfall , inches Overflow, MOD Overflow BOD, #/day 1.1 0.04 33 1.0 0.22 183 Three j ri.2 0.12 100 consecutive "S 0.1 0.08 67 days ' Lo.o 0.5 42 0.6 0.13 108 0.10 0.13 108 The above overflow events occurred in November and December in 1975. The overflow volume varied according to the magnitude and frequency of wet weather events. These data indicate the fluctuation in overflow events which affect stream impacts and control strategies. 4.7.1.3 CSO Control Cost To contain overflows a storm basin for holding excess flows was designed for Casey. This basin holds ten times the dry weather flow. Such a basin costs $48,000, and $2,000 in operating expenses are asso- ciated with treating storm flows. 4.7.1.4 Water Quality Analysis A new treatment plant has been designed and is in construction to replace Casey's existing facilities. The combined sewer holding basin is included in this project. There are no available data on water quality impacts associated with the CSO. No recent field samples have been collected by lEPA, and no water quality sampling was conducted by the engineering firm. 106 4.7.2 Description of Site Charactistics of Charleston Charleston Is a community of 16,500 located in Coles County. The receiving stream associated with combined sewer overflows is Town Branch Creek, which goes through the middle of town including park areas. This is a stream with a seven day ten year low flow of "0". This stream joins Cassell Creek, which ultimately empties into the Wabash River. Approximately 60 percent of the town is served by combined sewers, and there are eight overflow points located within the system. There are existing facilities for handling excess storm water at the treatment plant. The lagoon size, however, is not sufficient for handling all excess flows reaching the treatment plant. There are other overflow points throughout the system. 4.7.2.1 Planning Status of Community Charleston has a priority number of 1045 for combined sewer over- flow control projects. There has been a preliminary evaluation of sewer system characteristics, and a proposed program for evaluating water quality impacts will be initiated in the fall of 1980. The infiltration/ Inflow levels to the sewer system evaluated have been completed, and Step 1 funding will continue through the water quality evaluation program. 4.7.2.2 CSO Loading Characteristics The characteristics of the combined sewer overflows were described for a 0.5 inch and 0.75 inch rainfall. According to an engineering evaluation, six of the eight overflows discharged after a 0.5 inch rain- fall and all discharged after a 0.75 inch rainfall. On a yearly basis the flow volume treated at the STP was 1221 MG, the wet weather pumps directed 230 MG to the ponds, and 424 MG were bypassed directly to the stream. Thus, approximately 23 percent of the flows associated with the community receive no treatment at the present time. The average quality of overflows varied from 4 to 71 mg/£ for BODr and 10 to 396 mg/£ for suspended solids. 107 In estimating the characteristics of first flush, a volume of 9.0 MGD was considered first flush requiring transport to the treatment plant. Additional information regarding CSO overflows will be gathered in the proposed monitoring work. 4.7.2.3 CSO Control Costs Costs for correction of the combined sewer problems were estimated for two different alternative scenarios. Transportation and treatment of first flush and other flows was compared to a partial or complete separation of the combined sewer area. A 1979 evaluation of these two alternatives is summarized as follows: C apital Cost, $xlOVyr O&M Cost! $.x_lQV yr Sewer separation 6.24 0.88 Equalization, storage, & 9.61 • 2.62 treatment of flows The local capital investment is $1.5 million, and this represents a capital charge of $91 per capita. The total annual cost, which includes amortized capital, is $1,570,000 for the sewer separation project. The local annual cost of CSO control is estimated at $1,050,000, and this represents an annual cost of $64 per capita. 4.7.2.4 Water Quality Analysis The water quality data which have been collected thus far pertain to the receiving stream, Cassell Creek, to which the sanitary treatment plant (STP) discharges. Since 1973 there have been three collections of water quality data upstream and downstream of the STP. The Town Branch Creek, which receives CSO, discharges into Cassell Creek upstream of the STP. Table 4-20 summarizes the existing water quality data per- taining to Cassell Creek as monitored by lEPA. The proposed water quality monitoring program to be conducted in Step 1 includes the following sample program. Excludes amortized capital 108 Table 4-20 SUMMARY OF WATER QUALITY DATA FOR CASSELL CREEK Concentrations Sampling Period B0D5 , mg/il Dissolved Oxygen, mg/il Upstrpam Downstream Upstream Downstream July 1973 2 5 8.6 8.2 August 1973 2 4 8.3 8.0 September 1973 1 5 7.2 6.9 October 1973 2 7.5 7.4 November 1973 2 8.9 9.0 December 1973 1 8.9 9.0 January, 1974 1 9.0 9.1 February 1974 1 9.3 9.2 March 1974 1 9.3 9.3 April 1974 1 2 9.1 9.1 May 1974 1 3 8.9 9.0 June 1974 1 3 9.0 8.8 NH3-N, mg/ii Total Kje' Idahl N, mg/£ October 6, 1976 0.05 2.8 0.74 4.96 Composite Sample* pH units NH 3-N, mg/£ April 9, 1980** 7.9 8.0 <0.1 0.3 Sample * No BODg or DO sampling was performed. **Only pH and ammonia were monitored upstream and downstream of the plant. 109 1. sample upstream of CSO. 2. sample immediately downstream of CSO 3. sample one mile downstream of CSO 4. sample upstream and downstream of Cassell Creek junction. Two or three rain events will be utilized to determine the impact of CSO on the receiving stream. A report would be available in 1981. 4.7.3 Description of Site Characteristics of East St. Louis East St. Louis is a metropolitan community of population 70,169 located on the lower Mississippi River. The combined sewer system repre- sents two-thirds of the total system serving East St. Louis and drains an area of 4,800 acres. During wet weather events, overflows to the Mississippi may occur at two points. The first interceptor carries all flows up through 9.93 MGD, and the remainder are discharged directly to the river. The second overflow point occurs downstream of the East St. Louis wastewater treatment plant when flow rates exceed 30 MGD to the plant. Being located on the Mississippi River, East St. Louis experi- ences a unique problem of having river waters enter the sewer line at flood stage 9.5 for 3400 linear foot for one overflow point. The second overflow point receives river water at stage 11.5. Thus, there are intervals when sewers receive flood waters and flood gates are utilized. 4.7.3.1 Planning Status of Community East St. Louis currently has a priority number of 104 and 461 for CSO control projects. As part of Step 1 review East St. Louis evalu- ated the first flush component of their combined sewer overflow as to volume and concentration. Only two rainfall events were utilized to determine the first flush characteristics because of river flooding problems. Treatment of first flush or additional storm flows were con- sidered not cost-effective by consultants, and a site specific rule change was recommended. no 4.7.3.2 CSO Loading Characteristics Analysis of two rainfall events depicted the volume and concentra- tion of first flush and extended overflows in the East St. Louis system. Figures 4-8 and 4-9 depict the overflow profiles for the two events used to calculate pollution loadings to the Mississippi River. Figures 4-8 and 4-9 represent different overflow points during the same storm. The concentration and flow profiles appear similar to the stan- dard description of overflows. First flush volumes were calculated as 19.4 MG and 8.2 MG, respectively, during the storm of February 22, 1979, which represented approximately 0.9 inches of rainfall in a three hour period. Figure 4-10 illustrates the difference in overflow characteristics with rainstorm variations for the same overflow point as depicted in Figure 4-8. The first flush volume is only 5.3 MG for Figure 4-10, and the rainstorm of October 22, 1979 represented 0.7 inches of rainfall in four hours. Utilizing the concentration and flow profiles of Figures 4-8, 4-9, and 4-10, the first flush volume for East St. Louis is estimated at 20.9 MG per event, and the flow requiring primary treatment is 120 MG. The pollutant loading associated with first flush and the ten times dry weather flow criteria are estimated by the East St. Louis' consulting engineers as the following: Pollutant First flush loading. lOx DWF loading. . pounds per event pounds per event BODg 34,500 39,000 COD 99,000 104,000 TSS 177,500 101,500 4.7.3.3 CSO Control Cost To comply with Rule 602 East St. Louis' engineers evaluated several alternatives. To accommodate first flush flows at the treatment plant would require additional capacity of 21 MGD (this would double existing plant capacity). Also, additional costs for pumping 274,000 gpm a dis- tance of 7000 linear feet would be incurred. This was considered fi I 3 ' 1 ^ ( 1 f 1 ' J ( 1 >- UJ co a: X < Q O Q O CO CO CO L L, CQ O H li- li- o f^ o CO 111 (OOOIxiMdO) MOIJ 0=: 2 CO q: O X UJ o o o UJ m o in o in o 6 O o o 1 . . J_. 1 ( l/Buj) NOIlVdlN30N00 SNiiNsi/Ni nvjNivy 112 >- UJ o Q o _J o o li_ CD O CO (f) I- X ? 3 (OOOIx'lMdO) MOld o o O O o o o 00 o o o o o o CM \ O M m o o d 1 o 1 o 1 o 1 ( l/Bui ) NOIlVdlN30NO0 SNIWQI/NI nivjNiva 113 (oooi^i^do) Monj I { l/6ui ) NOIlVdlN30NO0 5 12 2 S 6 6 6 o J I I L__ SNIWSI/NI mVJNIVd 114 prohibitively expensive. Separation of sewers as a second alternative would require $53.3 million and annual costs of $690,000. The third control alternative consisted of storage of first flush with subsequent transportation to the treatment plant. The total capital cost of $11.6 million is the current estimate, and Table 4-21 presents an analysis of the costs to be incurred. Additional primary treatment costs are estimated at $10.8 million. Thus, the total capital cost of Rule 602 compliance is $22.4 million for East St. Louis. This repre- sents a capital cost of $79.80 per capita based upon a 25 percent local share. Total annual costs of $3,000,000, which include amortized capital, represent a cost of $43.00 per capita. 4.7.3.4 Water Quality Analysis In assessing the CSO control program no water quality monitoring was required. The consulting engineers for East St. Louis described first flush flows as having "an almost undetectable impact upon the water quality of the Mississippi River." In the 1979 Needs Survey data base, East St. Louis was described as contributing to aesthetic water quality problems, high suspended solids, and low dissolved oxygen levels in the receiving streams. 4.7.4 Description of Site Characteristics of Georgetown Georgetown is a small community of 4,100 people located in Vermilion County and discharges to Ellis Branch of the Little Vermilion River. This is a zero low flow stream tributary to the Wabash River. The combined sewer system represents 100 percent of the total system serving Georgetown. During wet weather events, overflows occur at two overflow points. Georgetown was placed on Restricted Status in June 1977 because of frequent bypasses due to hydraulic overloading. In the first 10 months of 1977, bypasses of the treatment plant occurred on 181 days. Enforcement action by lEPA was initiated in March, 1978 because the community had refused to continue in the Construction Grants program 115 Table 4-21 CONTROL COSTS FOR RULE 602 COMPLIANCE FOR EAST ST. LOUIS First Flush Control Costs 1. INFLUENT PUMPING $ 7,865,000 300,000 gpm (432 MGD) Capacity 2. EQUALIZATION BASIN 1,430,000 21 MG Concrete Lined Earthen Basin with 840-hp Surface Aerators and Washdown System 3. SUBTOTAL $ 9,295,000 4. DEVELOPMENT COSTS (25%) 2,324,000 5. TOTAL CAPITAL COSTS (ENR = 3150) $11,619,000 6. ANNUAL SYSTEM & M COSTS* 343,000 Primary Treatment Control Cost 1. CAPITAL COST FOR PRIMARY $10,761,000 TREATMENT AND CHLORINATION 2. ANNUAL SYSTEM & M COSTS* 538,000 Total Capital Cost of Rule 602 $22,380,000 Total Annual O&M Cost of Rule 602 ^$ 3,000,000** *Does not include amortized capital costs. **Estimated based on first flush and primary treatment and includes amortized capital cost. SOURCE: Russell and Axon, Evaluation of Combined Sewer Overflow. 116 in spite of water quality violations. This enforcement action resulted in Georgetown re-entering the grants program to correct deficiencies in treatment plant operation and to evaluate combined sewer overflow problems. 4.7.4.1 Planning Status of Community Georgetown currently has a priority number of 191 for combined sewer evaluation. The facility plan and combined sewer study amendment are complete at this time. The CSO study included water quality monitoring immediately downstream of overflows during storm events. On April 1, 1980 an amendment to Step 1 was granted which would estimate first flush characteristics and include a cost-effectiveness and a cost allocation analysis. This work has not yet begun. 4.7.4.2 CSO Loading Characteristics Monitoring of a rainfall event with an intensity of 0.75 inches in one hour provided a description of "first flush" and water quality concentrations in the receiving stream. Figure 4-11 illustrates the points A, B, and C which were monitored during dry weather, first flush conditions, and the receding limb of the storm event. The difference in loadings between points B and C represented the overall effects on the receiving strams of storm event discharges, including the treatment plant discharge. Figures 4-12 and 4-13 represent the 800^ and suspended solids loading profiles during storm events. Points A and C represent stream locations receiving overflows and the figures provide loadings in pounds per day. The sampling program depicted combined sewer and treatment plant loadings during wet weather events as well as the total loading to the receiving stream immediately following Georgetown's total pollutant contribution. Concentrations and flow rates were determined at approximately hourly intervals for the four monitoring locations. The maximum loading rate to the stream occurred at 5 AM during the March 12th storm. At this time the following breakdown of loadings rates was observed: 117 I- UJ (C I- - < ^ 42 VCP COMBINED SEWER JSl NO SCALE MILL ST. MONITORING POINT "B" TREATED EFFLUENT TREATMENT' V FACILITY . 7T / MONITORING POINT "D" Figure 4-11 GENERAL LOCATION MAP FOR MONITORING PROGRAM - GEORGETOWN, ILLINOIS eOi X Ava/aofl .. xm-i (r I o \ z lO N- d X 13 _j _J _j u_ < G: 00 z Q t— 1 < CO _l q: r-t 1 <* o Q QJ UJ S- Q 3 21 CD UJ • ,— Q. U. CO OO 1 \ C\J ro 119 / o to — I— o I o OJ -.1 ~ z .o en •00 iij I-. iD in ro CJ ^1 X Ava/ it- xnij sanos a3aN3dsns 120 Monitoring Point BOD Flux Percent of Maximum (Pounds per day) Hourly Rate B (upstream of sources) 3050 51 A (downstream of 1 overflow) 1450 24 D (downstream of treatment plant) C (downstream of both 6000 100 overflows and treatment plant) The above loadings represent contributions during a rainstorm of such magnitude that it has a recurrence frequency of once per year. Upstream sources, which exclude CSO and treatment plant loadings, repre- sent 50 percent of the storm loading rate to the stream. 4.7.4.3 CSO Control Cost Several alternatives have been evaluated for compliance with Rule 602. In the Facilities Plan submitted in 1976, the lowest cost option appeared to be a new sanitary sewer system for Georgetown combined with treatment plant upgradings. The 1976 estimated cost of sewer separ- ation was $3.45 million for capital cost and an annual operating cost of $34,300. (This operating cost excludes amortized capital costs.) A 1979 revised estimate of the projected capital cost is $4.5 million, and the total annual cost (including interest charges) would be $550,000. The local annual cost based upon 25 percent of the capital charges would be $170,000 or $41 per capita. The capital charge per capita is $274. 4.7.4.4 Water Quality Analysis Georgetown as part of the Step 1 program has monitored the pollu- tant loading reaching the stream during a wet weather event. The dura- tion and magnitude of the impacts of the discharges on the stream were not discussed in the engineering report. Between 1973 and 1978, lEPA performed three field investigations examining the stream impact of 121 Georgetown. Because enforcement proceedings were initiated against the community, an lEPA field investigation of the water quality impacts was conducted in 1978. This inspection consisted of collecting grab samples and recording visual observations for upstream and downstream locations in the receiving waters. In 1973 and 1974 similar field studies were performed. Table 4-22 summarizes the water quality data collected by lEPA where violations are known to exist. There was no effort made to describe the extent or duration of water quality impacts beyond the immediate vicinity of the community. Stream uses, aquatic biota impacts, and health effects associated with the town's CSO problems were not described or discussed in the field survey or engineering report. The samples collected, however, do indicate the quality of the receiving stream for varying wet weather events. 4.7.5 Description of Site Characteristics of Peoria Peoria is a metropolitan community of population 134,000 and is located on the Illinois River. Approximately 70 percent of the sewer system serving Peoria is combined or tributory to a combined sewer system, and there are 20 overflow points to the Illinois River within this system. Land use in the combined sewer area is approximately 30% public, 48% residential, 11% commercial, 6% industrial and 5% institutional. The sewer system varies in capacity to handle storm events, and there are segments which frequently overflow. Because of the Peoria sewer system characteristics, an innovative and cost-effective approach for resolving the CSO problem is being considered. A combination of on-line and off- line storage regulated by a central computer system is anticipated as the CSO control method for Peoria. 4.7.5.1 Planning Status of Community Peoria has been working on their combined sewer overflow problem since 1973. In 1973 a course of action was adopted, and in 1975 a Step 1 project was initiated. This study involved a computerized sewer level and rainfall monitoring program to determine the extent of CSO and to develop the alternative methods of treatment. Presently, Peoria is 122 00 O o o o o o r^ o o o o o o - — ~ CT) CO o CO o o •^ ^— I— 1 9\ *» #t •k •t 0i E CM o 1—1 CO CM o t— 1 o U3 CO CO O t— « r-t O t— I o o O •^ o 00 o o O O •V r^ r^ « •» 1 1 1 E CTi r—) o o s- ,—4 o 00 o o 1—1 CX3 4- rt r-^ •1— ^ en r^ < — 1 o o o o o o o o ■o o o o o o o c 1 — •cd- o o o o o (t3 to oo •» #» w* ^ o r-^ 1—1 CM ^ o o o •^ O) CT. uo CO o o o •^ u. 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(/) O ■— U 03 3 -»-> -o C •.- QJ > E ■I- +-> -C 03 C QJ •I- S- +-> e o >> •O QJ QJ S- -M 03 LO •r- Q (JO O £23 ^ D- S- "O CO I 3 03 CU 1/14-^ E "O fC O TD •-- 3 QJ QJ S- r— CU CO 1 — (/) D_ (J x: T3 JD 03 C +-> C 03 JD -r- , 03 4- O r— +-> C O 00 O +-> QJ 03 03 ■•-> 3 3 S- •■- QJ CU I — C O Q- S- .C 03 C +-> (O fO (— > et CO (J JD u -a CO QJ +J O 131 Rule 602 costs are segregated into those attributed to first flush and primary treatment. Those costs listed in Table 5-1 for first flush and primary treatment each include the costs of treatment and pumping for 132 dischargers. The expense of installing primary treatment equivalent to ten times the dry weather flow is greater than that of first flush; however, the BODj. and suspended solids removals are greater for first flush treatment. As the primary treatment capacity for CSO is reduced, pollutant removals and annual costs decrease. If the primary treatment capacity islimitedto 2 times the dry weather flow, then pollutant removals obtained are <1% of the total uncontrolled CSO loading. Three special categories of dischargers are described according to the costs incurred and reduction in pollutants obtained. The use of sewer flushing as a best management practice is evaluated for those commun- ities with priority numbers greater than 806. If future funding is ques- tionable, the institution of such a practice would reduce water quality impacts. The $17 million in annual costs due to sewer flushing would be completely sustained by the affected communities since such measures are not eligible for federal funding. The pollutant reduction of 15 to 40 percent may be as great as that associated with first flush treatment; and annual costs for sewer flushing are approximately 50 percent of those for first flush treatment. The costs and pollutant removals of smaller facilities are also of interest in evaluating economic hardship. Municipalities in which combined sewer populations are under 3000 represent less than 1 percent of pollutant removals and 6 percent of the total annual cost.* There are 27 municipalities discharging to major streams, and these facilities represent 37 percent of the pollutant removal obtained from implementation of Rule 602. The costs of pollutant removal are only 21 percent of the total incurred. To depict the efficiency of each treatment process, the cost of removal per pound of pollutant is presented in Table 5-2. The values *Total Annual Cost is $72.5 million per year, for all affected communities. 132 Table 5-2 COST EFFECTIVENESS OF VARIOUS TREATMENT SCHEMES Treatment Scheme $/(Pound BOD Plus TSS Removed)^ Rule 602^^ - Aggregate 1.70 - Towns <3000 PE 2.40 First flush treatment^ 0.94 Primary treatment lOx dry weather flow 7.40 Primary treatment 5x dry weather flow 7.90 Primary treatment 2x dry weather flow 3.30/12.00 Best management practices 0.36/0.97 Dischargers to major streams 1.00 f Typical sewage treatment plant costs 0.55 Notes: a) January 1980 cost basis, includes annualized capital cost. b) Includes both first flush treatment at 2.5 times dry weather flow plus primary treatment at 10 times the dry weather flow and disinfection. c) First flush treatment for 2.5 times dry weather flow includes pumping. d) Costs based on sedimentation plus pumping for all except 2x D.W.F. First value is without additional pumping costs. e) Combined sewer flushing based on 15% to 40% removal. f) For 1 MGD plant, assumed capital cost of $4.6 M and operating cost of $257/million gal., all assigned to BODr and SS removal. 133 of Table 5-2 represent the incremental costs of each treatment process. Clearly, first flush treatment. is the more cost effective part of Rule 602. To increase the removal of additional BODj. and suspended solids loadings, the next process step adds incremental costs which may be up to 8 times more expensive. The economies of scale are evident as the capacity of a primary treatment process decreases from ten to two times dry weather flow. Unit costs simultaneously increase from $7.40 to $12.00 per pound of pollutant removed. There is also a cost differential in treatment efficiency between small towns and larger ones. The average removal charge for towns of population less than 3000 is $2.40 per pound removed, while towns on large streams (larger towns) only incur removal costs of $1.00 per pound of pollutant. Best management practices (sewer flushing) with 15 to 40 percent removal have costs equivalent to^ or lower than first flush removal, depending upon the site specific characteristics. The values of Table 5-1 and 5-2 depict the typical cost-effectiveness and quantity of pollutant removed for various treatment processes. Such cost estimates must be considered as order-of-magnitude approximations describing relative effectiveness. This treatment efficiency is an impor- tant concern, especially for the smaller towns which face higher costs or lack of funds. Also of concern is the balance of controls and level of environmental protection. The following section describes the water quality impacts in a qualitative narrative. 5.3 Environmental Aspects of CSO Control Environmental effects of CSO depend upon the receiving stream and level of treatment or protection provided. Chapter 4 included the cate- gorization of receiving streams according to flow as intermittent, inter- mediate, and major. Of the 54 receiving streams described, the water quality of 37 is impacted by uncontrolled CSO discharges. 134 Rule 602 and other control alternatives each provide a level of pro- tection for the receiving stream. The adequacy of this protection depends not only upon the intensity of the rainfall but also upon the contributions of non-point sources. In evaluating the level of protection provided, the rainfall events receiving complete treatment result in a CSO effluent quality for first flush equivalent to a BOD^ removal of 85 percent and suspended solids removal of 80 percent. Such removals result in an effluent comparable to the wastewater treatment plant effluent with slightly higher suspended solids concentrations. For those flows receiving primary treatment only, assuming a BODr and suspended solids removal of 25 and 30 percent, respectively, the BODj. effluent quality would also be comparable to a wastewater treatment plant effluent. The suspended solids levels would be higher from primary treatment than those associated with treatment plant effluents. However, primary treatment removes the larger particle sizes and thus reduces the deposits to the stream bottom just below the outfall. Suspended solids contributions from stormwater may exceed any CSO contribution treated or untreated. For those rainfall events which exceed the capacity of the treatment plant, runoff volumes from 10 percent to 90 percent of the total may be captured and treated. This runoff percentage treated depends upon rainfall intensity and treatment plant capacity. Fifty percent runoff treatment of the first flush volume occurs during higher rainfall intensities. The BODj- and suspended solids concentrations associated with excess first flush flows would be less than those concentrations of Table 4-2. Table 5-3 summarizes the level of treatment obtained from various control alternatives and the associated water quality impacts. These impacts are described as percentages of rain events receiving full or partial treatment. Water quality effects attributed to first flush concen- trations are minimized by Rule 602 criteria, as indicated in Table 5- 3. First flush flows for 70 percent of all annual rainfall events are treated by all dischargers, and over half of the communities could treat all first flush flows utilizing an estimated volume of 2.5 x DWF . Primary 135 +-» o Q. 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O) X3 •1 — i+- UD E fO +-> +-> +-> JZ O ^ 1- CU s^ O) fO CO r— CO C S- 3 > cu S- I — 3 &« S- .- 4J O (t3 S- • r- •r— 1 — o o s: to u_ .C cn Ll_ 5 4- ^ M- 1 CO •^- S- cu CU O o o , — u U5 •>-> 3 ■r— S- O c 03 a: 4-> -C CU CO 3 E a +-> X3 E E to • 1 — E c c O i_ 3 3 fO 4- o S- Q. C XZ O 4- CO +J CO +-> c: >> , C CU co C S +-> 5- o E CU o •r- CU +J (O E +J s_ +-> -»-> cuo cu O fO ex , — i- C\J en s_ •.- CU E fO 4-> O fO o s_ s- cu CI. CO tX) c 4- a. en X fO (U > fO c s- (U +-> CO o o o JD T3 > CU C7> s_ t. cu «o Q. CO CO 4J •r— c -o cu > -o cu cu , — o , — >) cu c J3 o o cu +j fO TD cu -a E • CD 3 £= +-> CO ro c CO sz cu n3 +-> CO cu CU ^/) S- S- CO Ci. fO CU r^ CO cu cu i- 1 3 cu 1 — 03 03 O 138 treatment of ten times the dry weather flow provides full treatment for 13 rain events per year for all dischargers, and half of the communities can treat 58 percent of the rain events. The effect of drainage area upon storm flows is to increase the discharge volume which can be treated beyond the Rule 602 criteria for many of the dischargers with a regular frequency. Smaller primary treatment capacities are less effective in reducing the pollutant loading to the stream. The associated effects of eliminating disinfection are described in Chapter 4. The balance between health risks and adverse effects on aquatic biota may depend upon site specific information. Exemption of municipalities with less than 3000 population served by combined sewers or discharging to major streams is defined as no treat- ment of CSO. There are streams in these groups which have been identified in Section 2 as water quality impacted. Thus, exemption would imply con- tinued adverse effects. Management practices (exemplified by sewer flush- ing) required in place of Rule 602 may reduce water quality impacts simi- larly to first flush treatment. The number of towns actually practicing such techniques today is limited. The assumed removals (15-40%) for BOD and suspended solids need to be demonstrated in communities in Illinois before widespread application of the control technique is implemented. 5.4 Summary of Cost-Effectiveness The application of Rule 602 appears to result in a level of water quality protection which insures treatment of concentrated first flush flows and some incremental removals via primary treatment. Rule 602 does not result in complete primary treatment for all excess storm flows but rather a portion, varying from 13 percent to 100 percent depending upon the site specific conditions. This incremental removal attributed to primary treatment is more costly than first flush pollutant removals and provides a lower level of protection than specified first flush capacities. Smaller primary treatment plant capacities are costly compared to other removals and provide treatment of less than half of the rainfall 139 events per year. Water quality protection is decreased and incremental costs are increased over Rule 602 design criteria. Exemption of small dischargers should be considered upon a cost basis and their contribution to the general CSO pollutant loadings. There may be site specific water quality impacts requiring treatment; however, the cost of treating CSO is generally higher than the average cost ($ per pound pollutant removed). The 27 dischargers located upon major receiving streams typically incur lower than average costs per pound of pollutant removed. The number of major receiving streams with water quality impacts due to CSO isa minimum of ten, as identified in Section 2. For the fourteen communities with priority numbers greater than 806 located on major streams, the requirement of CSO treatment may be more appropriately based upon water quality needs. 5.5 Limitation to the Analysis The evaluation of treatment costs and environmental effects of com- bined sewer overflow control is dependent upon the data base and accuracy of estimating methodologies. The factors representing the major limitations to the analysis are lack of data regarding sewer system characteristics, general cost estimating procedures, methods for determining annual and event CSO loadings and specific water quality impact assessments. In avaluating the effectiveness of Rule 602, the data constraints and estimating methodologies must be considered. The general lack of an adequate data base became apparent after reviewing lEPA and U.S. EPA information. There are 25 on-going studies for specific comnunities to address combined sewer problems; however, the treatment of combined sewer overflow has not received detailed analysis until recently. Discrepancies existed in identifying affected communities, and even the 132 municipalities specified in this report probably do not represent the entire data base. Costs were available in engineering reports for 55 of 132 munici- palities and cost estimating equations were utilized for tne remainder. The costs of 77 communities are considered conservative estimates since all 140 transport costs were not included. Also, engineering evaluation and design costs are not included in the treatment cost estimates. For the 77 com- munities where costs were not available, the site specific characteristics could alter individual estimations by more than 100 percent. The engineering cost estimates of Exhibit 4 represent values developed based on site specific considerations. Exhibit 4 costs represent 88 percent of the total cost of Rule 602, and thus, the general cost estimate is considered indicative of the order of magnitude of costs incurred. The estimation of pollutant loadings contributed by combined sewer overflows represents the area of greatest inaccuracy. Two methods are utilized to calculate annual CSO loadings. The variation in values provided by these methods is a two-fold range for suspended solids and three-fold range for BODr. This variation is an indication of the uncertainty regard- ing the magnitude of CSO loadings. Depending upon the land use character- istics, interval between storm events, size of the drainage area and the intensity of the rainstorm, the runoff characteristics will vary. The U.S. EPA conducted detailed site studies of CSO characteristics and the results of these studies also indicated a range in discharge character- istics for different sized communities. The CSO loading of any individual community cannot be accurately described without specific knowledge of the system; however, the general aggregated loadings represent an indication of the problem. The importance of BODj. and suspended solids loadings attributed to CSO cannot be fully evaluated when such a range is possible. The level of protection or treatment provided by Rule 602 was assessed in terms of rainfall events per year. General flow calculations based upon the "Rational Method" are subject to errors due to the simplification of the method. Without detailed sewer studies, this method represents a first approximation. The calculation of primary treatment plant capacity was based upon design average flow or dry weather flow and represented an accurate base for costs and level of protection. The unknown, of course, is discharge or runoff volumes with time, and this varies with each rain event. Any results or implications of the analysis relating to level of protection must be considered as general results which require 141 additional site specific data for decision-making. The magnitude of CSO water quality impacts is not well documented in Illinois. General field evaluations are available for less than half of the dischargers, and detailed field studies have not been con- ducted for even one discharger. The five site studies represent the best documentation of CSO and yet much information is missing from these. The duration of CSO effects may vary from a few days to months; however, there is litle or no information on this aspect. It is a function of receiving stream, discharger, and weather conditions. To accurately depict CSO effects and quantify these effects compared to other non- point source contributions would require at least a year of field studies per town, according to consulting engineers contacted. Without an accurate assessment of environmental conditions, the benefits of Rule 602 cannot be properly addressed. 142 143 6. ECONOMIC IMPACTS OF RULE 602 6.1 Introduction The economic considerations of implementing Rule 602 or other alter- natives pertain mainly to the generation of capital and operating funds by the affected municipalities. The capital costs of combined sewer over- flow treatment may be funded up to 75 percent by the state and/or federal government. Local governments would be expected to generate the 25 percent of the capital investment as well as the operating and maintenance cost of control facilities. Those communities whose priority number is greater than 806 are presently eligible for only Step 1 or planning funds. Con- struction funds may eventually (5 years or more) become available but there is no certainty of that funding. There are additional concerns regarding the conflict between U.S. EPA policy and Rule 602 of the Water Pollution Regulations in determining the level of CSO treatment required. The generation of capital funds, the extent of the local government tax burden, and the economic relief associated with alternative controls are discussed in this section. 6.2 Capital Investment Impact Upon Local, State, and Federal Governments The implementation of Rule 602 is estimated to require $476 million for those communities outside the TARP (Tunnel and Reservoir Plan) area. This implies the local government share is $119 million and state/federal funding will produce the remaining $357 million. The total capital invest- ment for projects with a priority number greater than 806 is $147 million or 31 percent of the total CSO funds required. The ability of the commun- ities to obtain any state or federal funding for these projects is ques- tionable. 144 The impact of generating 25 to 100 percent of the capital invest- ment for CSO varies from community to community depending upon the size of the community and magnitude of funds required. Figure 6-1 depicts the local capital cost burden according to town size, assuming all projects receive 75 percent state/federal funding. The smaller municipalities (population less than 2500) must generate on average $50,000 to $100,000 and some as high as $300,000 for capital investment. Cities of 2500 to 10,000 population averaged a capital investment of $200,000 to $300,000; and those cities of population greater than 10,000 incurred an average capital cost of $500,000 to $1,000,000. These costs, of course, represent only one-fourth of the total incurred by the municipality. The average level of indebtedness associated with CSO control imposed upon communities varies from $20 to $40 per capita; however, individual sites may incur higher costs. This level of increased debt can be compared to typical municipal outlays and revenue. Table 6-1 summarizes the financial characteristics of various town sizes. Total annual capital outlays range from $20 to $81 per capita, depending upon town sizes. Thus, the local share of CSO control represents a minimum of one year's total capital budget, and for many this capital outlay would absorb all capital investment funds for several years. 6.3 Impact of Increased'Operating Costs on Local Governments The increase in annual costs of wastewater treatment due to CSO con- trol varies with magnitude of the CSO problem and town size. The annual cost includes operating and maintenance expenses in addition to 25 percent of the total amortized capital charges. Table 6-1 presents the distribu- tion of increased annual costs to the affected communities. These increased costs represent additional taxes or loss of services to the residents of impacted municipalities. For 55 municipalities or 47 percent the increase in annual costs is less than $20.00 per person or $80.00 per household. 145 «-H O o •% A o o .0 *% #t r— 1 C\J 1— 1 •» A IT) O .-H O O O O O ■+- CO UD 00 ■+- -t- ■0 M I— I •« 0\ CO t-t LO >- 1 ■«^ »— 1 2: ,-1 0\ ra Q} ^ S- ^ ^ A 03 JZ 00 LD >- tft -!-> CQ t— 1 «/) 00 1 CJ .—1 .-• 1 — KO fO 4J CD #V •* •1 — 5- _1 cx 3 <: fO cn 1— CO Lf) •1 — 1 — 1 Ll_ Cl. 1 — <: m C_) u Ll_ 1 _j >-• 2: #t A H— 1 t— =) c\j ro CQ 1— f-i H— 1 Q #t *» .-H CM o o o o o o o o in o o o o o LO V «;:1- 00 O 00 T-i f—i r-i UD 146 Table 6-1 MUNICIPAL FINANCE CHARACTERISTICS BY POPULATION SIZE 1971-1972 1979 Percent Expenditure Town Ex penditure. E> (pe nditure. of Total Category Size $ per Capita $ pe r Caf )ita Revenue General 100,000+ 227.22 441 100 revenue 50,000-99,999 25,000-49,999 10,000-24,999 5,000- 9,999 2,500- 4,999 less than 2,500 146.76 126.17 114.61 107.37 101.84 80.35 285 245 223 209 197 156 n II II Capital 100,000+ 40.98 8C 18 outlay^ 50,000-99,999 25,000-49,999 10,000-24,999 5,000- 9,999 2,500- 4,999 less than 2,500 23.41 21.91 20.64 17.12 16.18 9.90 45 42 40 33 31 20 16 17 18 16 16 13 Sewerage 100,000+ 6.62 _ _ (includes 50,000-99,999 6.48 - -* capital 25,000-49,999 9.73 19. 40 8 outlay) 10,000-24,999 10.46 20. 90 9 5,000- 9,999 11.18 22. 40 11 2,500- 4,999 10.81 21. 60 11 less than 2,500 2.30 - — Note: a) General revenue updated utilizing! Munici ipa 1 Price Ii ndex ratio of 1979 to 1971 of 1, .94. This is consi de: red a maximum increase. b) To update to 1979, the MPI was utilized as in "a". c) Sewerage costs updated using U.S. EPA indices for operating secondary treatment. SOURCE: 1972 Census Government Finances of Municipalities and Township Governments 147 Table 6-d LOCAL IMPACT OF ANNUAL COSTS OF IMPLEMENTING RULE 602 Annual Costs, ^ $ per capita Number of Communities 0.00 - 20.00 55 21.00 - 40.00 39 41.00 - 60.00 4 61.00 - 80.00 6 .81.00 - 100.00 5 101.00 - 120.00 2 121.00 - 140.00 3 141.00 - 160.00 2 161.00 - 200.00 1 201.00 - 250.00 251.00 - 300.00 1 Total 118 Notes: a) The annual costs include operating and maintenance costs and amortized capital costs of 25% of the total investment. b) Of the 132 communities 6 had no costs incurred and for 8 sufficient data were not available. 148 The annual costs rise to $20,00 to $40.00 per person for an additional 39 communities or 33 percent of the total towns evaluated. The remaining 20 percent of the impacted communities would incur increased costs between $41.00 and $300.00 per person for CSO control. The communities affected by these high costs range in size from 1,000 to 74,200 population. The size categorization for the 23 communities with increased costs above $40.00 per person are as follows: Population Number of Towns <1000 6 1,001 - 3,000 5 3,001 - 5,000 5 5,001 - 10,000 1 10,001 - 15,000 3 40,000 2 70.000 J, Total 23 Eleven of the 23 communities with greater costs have a population less than 3000 but there are intermediate-sized communities which may also incur costs of $160 to $1200 per household per year. These costs are incurred every year and would increase as operating costs inflate. Higher taxes of $160 to $1200 per household represent several fold increases in property taxes, depending upon the town size and tax level. The annual costs of CSO control can be compared to the general revenue of various town sizes. Over 50 percent of the affected muni- cipalities would incur additional costs greater than $20 per capita, which represents 5 to 13 percent of the total revenue generated. This is the minimum incremental expense. A far greater increase is anticipated for at least one-third of the communities. For at least 16 small towns (population less than 5,000), annual budget increases exceeding 20 percent would be expected. Such a large increase could only be sustained by an increased tax burden or reduced services. Therefore, there appears to be significant economic impacts upon combined sewer communities. 149 Another concern, of course, is the fact that these costs are con- sidered to be increments to other facets of pollution control, such as upgrading or expansion of the treatment plant. Thus, the municipal- ities in reality face higher total costs than these presented. Also, interest rates are an important factor in ascertaining the true cost to communities. 6.4 Impact Upon the Agricultural Sector No direct costs are anticipated for the agricultural sector as a result of Rule 602 implementation. 6.5 Impact Upon Commercial and Manufacturing Sectors Commercial and manufacturing facilities located in combined sewer or flood prone areas may incur costs for storm water control. Onsite detention or retention of stormwater may be stipulated by communities to reduce the immediate volume impact during a storm event. In Peoria, Springfield, Decatur, and Kankakee onsite detention is not practiced effectively but the sanitary district or community does have the capa- bilities to stipulate such actions. There is no estimate available of capital costs incurred by industry for stormwater control due solely to combined sewer conditions. Such costs, however, should be considered as a potential impact of combined sewer control. 150 6.6 Summary Compliance with Rule 602 require significant funds at the local, state and federal level. Sufficient funds to remedy all CSO problems do not appear to be available. The magnitude of local impact varies according to town size and severity of the CSO problem. The economic costs imposed upon the 132 Illinois communities represent only a portion of the total impact. Funds at the state and federal level of $357 million represent all state pollution control funds for a two year period. Any increases in manufacturing employment levels and goods outputs must be balanced against the local economy effects of higher taxes and reduced services. Thus, Rule 602 can be considered a large sink for capital investment in Illinois which reduces the availability of capital for alter- native pollution control investments. 151 References 1. Illinois Pollution Control Board, Chapter 3 - Water Pollution Rules and Regulations , 1972. 2. Rhett, John T., Program Requirements Memorandum PRM No. 75-34 and Program Guidance Memorandum PB-61, U.S. Environmental Protection Agency, December, 1976. 3. U.S. General Accounting Office, Large Construction Projects To Correct Combined Sewer Overflows Are Too Costly , U.S. Dept. of Commerce, NTIS No. PB80-126949, December 28, 1979. 4. U.S. Environmental Protection Agency, 1978 Needs Survey Data Base Printout. 5. Ciecka, J. E., and Zerbe, R. 0., Economic Impact of a Delay in Com- pliance by Municipalities with Combined Sewer Overflow Regulations, IIEQ, No. 76-11, July, 1976. 6. CHpM Hill, 1978 Needs Survey Cost Methodology for Control of Combined Sewer Overflow and Stormwater Discharge , U.S. EPA 430/9-79-003, Feb. 10, 1979, pp. 3-2. 7. U.S. Environmental Protection Agency, A Report to Congress on Control of Combined Sewer Overflow in the United States , 430/9-78-006, October 1, 1978, pp. 7-10. 8. U.S. Environmental Protection Agency, Benefit Analysis for Combined Sewer Overflow Control , EPA-625/4-79-013, April, 1979, p. 15. 9. Illinois Environmental Protection Agency, "Procedures for Determining Compliance with Rule 602 (c) of Chapter 3: Water Pollution Regulations of the Illinois Pollution Control Board," May 12, 1979. 10. Rhett, John T., "Grants for Treatment and Control of Combined Sewer Overflows and Stormwater Discharges, PRM No. 75-34, Program Guidance PG-61, December, 1976. 11. Heaney, J. P. et al . Nationwide Evaluation of Combined Sewer Overflows and Urban Storm-water Discharges , EPA-600/2-77-064, March, 1977. 12. Illinois Environmental Protection Agency, Urban Stormwater Management in Springfield Study Area , 208 Water Quality Management Program, February, 1979. 13. Wanielista, Martin P., Stormwater Management Quantity and Quality , Ann Arbor Press, Michigan, 1978, p. 208. 1.52 14. Holden, J., Health Effects Due to Cessation of Chlorination of Wastewater Treatment Plant Effluents , IINR, February, 1979. 15. Crites, R., and Viga, A., An Approach for Comparing Health Risks of Wastewater Treatment Alternatives , U.S. Environmental Protection Agency, EPA 430/9/79-009, September, 1979. 16. Cabell i, V., Dufour, A., et al . , "Relationships of Microbial Indi- cators to Health Effects on Marine Beaches." 17. Cabelli, V., "Swimming Associated Disease Outbreaks," Journal of Water Pollution Control Federation , June, 1978. 18. Greening, V. Yee, and Englebrecht, R., "Microbial Indicators for Biological Quality of Chlorinated Wastewater Effluents." 19. Jolley, Robert 1., editor. Water Chlorination, Environmental Impact and Health Effects , Vol. 2, Ann Arbor Science, Ann Arbor, Michigan, 1978. 20. U.S. Environmental Protection Agency, Disinfection of Wastewater , Task Force Report, EPA-430/9-75-012, March 1976. 21. Drehwing, F. J., et al , Disinfection of Combined Sewer Overflows , U.S. Environmental Protection Agency, EPA-600/2-79-134, August, 1979. 153 APPENDIX 154 APPENDIX TO CHAPTER 3 Index Used to Update Costs (Based on U.S. EPA Sewage Treatment Plant Index) Year Index Value 1970 137 1971 156 1972 192 1973 207 1974 222 1975 261 1976 375 1977 412 1978 438 1979 545 155 APPENDIX TO CHAPTER 4 Derivation of Discharge Volumes for First Flush and Primary Treatment The derivation of runoff volumes is based upon application of the Rational Method and the geometric figure shown below, representing the pattern of runoff. According to the figure the volume of runoff is 1.34 T^Qp where T^ is time of concentration and Q is peak flow. First flush was assumed to occur in the first hour of discharge which also equalled T^. Therefore, first flush volume is calculated as follows: Total volume of runoff = 1.34 T P c Volume of first flush = 0.5 T c^p 0.5 Q T or P c 1.34 Q T P c (total volume of runoff) or 0.37 X total runoff volume LOSSES , (l-C) IDA RAINFALL-EXCESS, V,» CIOA TRIANGULAR RUNOFF HYDROGRAPH (DURATION OF RAINFALL EXCESS, D « THE TIME OF CONCENTRATION^ Tc ) -VOLUME OF runoff: V2'l.34 0p Tc CI DA = 1.34 Q T P c T^=D Qp = 0.75 CIA Tc 1.67 Tc Where Qp = ft^/sec I A = in./hr = ac 156 To determine extended rainfall volumes the figure below represented the pattern of discharge volume with time. Q was assumed to persist for D-T time and the volume of runoff equalled Q D, where D is the duration C M of the rainstorm. LOSSES, (l-C) IDA RAINFALL EXCESS.V, • CIDA RUNOFF HYDROGRAPH (DURATION OF RAINFALL EXCESS, >THE TIME OF CONCENTRATION, Tc) VOLUME OF runoff: Vi'OpD Since V, =V2 CIDA = Qp D Therefore Qp = CIA Where Q = ft^/sec = in./hr A = ac SOURCE: Reference 13, pp. 121 and 122. 157 Kev tn Exhibit 1 X - Indicates municipality has finished or is completing this phase for Steps 1, 2, 3 S - Submitted C - Complete IP - In Progress Notes: a) Following definition of planning actions is utilized: Step 1 - Planning Step 2 - Design Step 3 - Construction b) Evaluations performed in the planning process may be reported as (1) facility plan, (2) I/I study, (3) SSES c) Priority number represents the funding position of these projects related to CSO. Highest priority projects are those designated 1 through 200. SOURCE: lEPA Planning Status Report, 1979. 158 ■o ■o o o o. •> 3 o -o i- S- 0) 4-> a. TD 1/1 c c t— 3 o LT) U- o > +JU ••- t. 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O) 1 — Q. -0 l/l re >, a Q. 1 — O) C 1 — +-> C 00 to -o 1 — •r— c 3 4J Z2 to •r— "1 — JT , — OJ to •r— i_ -0 •r- .c s_ re cr to en s 3 X to 4-> <4- O) QJ ^ 4-> II II II II II II II II II to re re 3 i-H CNJ CO «;J- LO UD r^ CXD -a re 4-> O JD 182 Key to Exhibit 4 Notes: a) Annual average flow represents 1979 average of DMR reports submitted to lEPA. b) Daily maximum is highest reported in 1979 on DMR. c) Design average flow is the average flow capability of the treatment facility according to equipment design. d) Primary flow equals ten times the dry weather flow or design average flow, whichever is available. For towns where CSO is partial problem, the flow equals 10 x 100 gal/capita x population served. Design figures from facility plans also utilized. e) Secondary flow equals 2.5 times the design average flow or one of the following: 1) 2.5 X 100 gal/capita x population served 2) 2.5 X 100 gal/capita x total population 3) design data 183 T3 3 »o E o •r— c ■*-> t— 1 (/) UJ (/) cu 4-> 10 -!-> O •r— o '.r- c O •r- (O •I— O OO LU CU O on o o o o o I— v^ o -»-> •« CJD •<- 4-> CTt Q. I/) I— I O -(-» n3 I/) E s- o - UJ •I- fl3 H- +-> •> •I- •!- +J XI Q. 00 O fO O 2:00 ■)-> «/> *^ O >> O > 4J f— S_ 3 <0 3 O +J 00 ■)-> Q. o r- S- D- 4-> Q. C 3 XJ E c cu fO E s- +-> •> (1) «\ •* rtJ CD 3 E E cu 4-J c: cu 4-> +J to s- fO •r- to •1 — n3 '1 — 03 E 4-> CO O) c +-> O) 4-> CU -t-> S- O) T3 fO S- (O S- 00 E +-> d) 0) +-> +J -(-> +-> -l-> CO 4-> to 3 cu 4-> to S- C •1— •1 — n3 i- fO s- .— E (T3 i_ -0 •!- 1 — XJ 1 — XI CU OJ CJ cu ■ Q. S- 2 (O E JD ra J2 (O 4-> cu ^- cu " n3 fO t/) • 1 — 1/1 s- to +-> +-) sz 4-> x: -l-> -a x> 1— CL XJ s- S- O) s_ O) i. 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