TD 741 15 Cornell University Library TD 741.16 The Iowa state college sewage disposal p 3 1924 003 634 858 •^ i l o Id; •sa-^J -10— ru. 5 GOOOO - 4000 O : >i - ^20000 - L 60000 ID '^SOOOO - O 40000 : 20000 ■ CSOOOO - I,, eoooo - 040000 - I/) : ^ 20000 - K 80000 - 50000 - O 20000 ^ FIG. 6. jndav. rr i„y iS. = da y Wedns doyT n Sday h id oy Saturday, 1 1 1 1 7, i/j/ f^ ^L-l- -J ^ - 4- - Lft "~N " As ~V - ■- — - ^l- = i^ h rjy ^ f] 4 t# UN p ^ t ^ W ^^ >::iV 1 'P' 2 Cjcl ^f ' (. ,r ■V- <^ DC 7 , . 1 1 1 1- rt^i 5r;:-z ^^ _ _ _ - F- -'^-i _ v^R- -I'-v _ _i A 7 - J-^ ^ffi - ^ ^^ M N n f pw" =f^^ A f^ A ^ t Oc +.(j ' X ^~ ic nk tfihi, 'Jtop nd.O r+ I? T R 1 3 ■ fk Jhhiq ■^ ^ _;7 I j ,\ - 1 - / - - _/- — M. - ■ + ~^^ ^ Lfl TT -f^M- >^ t^ -i .L^ ^^^ J ^_„ H -T f^v DC 15' 3c fiU Dc r? IfX' 8 be ■|0 n-- l?i-, o'.4ii^ i I / ^hu:q !?c •ir/ A f- A IL ~ - -- b - b .^^^ P F _ ±: - 4 i^ *2p H. 3C ^y ^ - -J -ft .ret^ —11— siderable waste also comes' from the laboratories and boiler rooms, and several thousands of gallons of sewage per day are contributed by the college creamery. The sewage is usually much stronger than is common. Pig. 6 is interesting as showing the flow of sewage during each hour of the day, and the variations from day to day. The disposal plant has not yet been operated at full rate during the winter season, owing to the fact that heretofore the long college va- cation has occurred in the winter, and during this vacation there is very little sewage floating. During the winter of 1898-9 the sewage was allowed to flow without attention continuously on one bed until, owing to the very severe cold weather and the small volume of sewage, it finally froze up, late in January. This winter more attention has been given the plant, and although the volume of sewage is very small no serious trouble has been experienced. One bed has been furrowed, and the sewage is allowed to flow intermittently on different portions. The long college vacation will hereafter come in the summer time, and next year the plant will be operated with a larger volume of sew- age. It is hoped to obtain information as to the operation of such a plant in Iowa winters, which will be of value to Iowa engineers. In connection with the operation of the plant many temperature records are kept. Since April 26 ,1899, the temperature of the sewage before it enters the receiving tank has ranged from 47 degrees F., October 17ch and November 14th, to 78 degrees F., September 5th and September 27th. The temperature of the sewage in the flushing cham- ber has ranged from 48 degrees P., December 20th and 27th, to 77% degrees F., September 5th. The temperature of the effluent has ranged from 39 degrees F., January 7th, to 76% degrees F., August 29th. At the depth of 12 inches in the filter beds the maximum temperature has been 79 degrees F., July 21st; at the depth of 24 inches, 78 de- grees F., and at the depth of 36 inches, 76 degrees F., both July 21st. During the present season the frost penetrated at one time over two feet into portions of the beds not in use, and one year ago it froze to the bottom. A complete record of the temperature observations will be published when the investigations have progressed further. By the cooperation with the author of Professors Weems and Pam mel, o! the State College, who will themselves discuss their work, regular chemical and bacterial analyses of the sewage before it en- ters the receiving tank, of the sewage as it fiows on the filter beds, and of the eflluent have been made. The first object of these investi- gations has been to develop the conditions and results of the opera- tion of this actual working plant, under Iowa conditions, as this will furnish the data needed for designing and operating plants in this state. When this is accomplished investigations of various special questions relating to sewage disposal will be undertaken. It is o. —12— course too early to draw conclusions from the work so far done, and what is given here must be considered as merely preliminary. The complete results will be published later by the College. Already, how- ever, the results have considerable bearing upon one of the most im- portant recent developments in sewage disposal, the "Septic tank." The contents of the receiving tank at Ames are removed intermittently instead of continuously as in the English septic tanks, and instead of the air being excluded fresh air is drawn in at each discharge. We are coming now to believe, however, that it is not necessary to exclude the air from the septic tank, and there is no doubt that the Ames tank is greatly beneficial in effecting "a partial purification of the sewage, and especially a preliminary breaking up of the organic compounds which leaves them in forms more readily acted on by the purifying organisms of the filter beds. The chemical and bacterial analyses show that the same purification processes go on in the Ames tank as in the English tanks, and to a much greater extent in the shorter time the sewage remains in the tank than one would expect. The sewage at Ames is usually much stronger than ordinary sewage, and a consid- erable part of the organic matter is removed by seiJing out as sludge in the settling chamber. Besides this probably some of the organic material escapes from the tank in the gaseous form, and the details of the chemical analyses, as will be explained by Professor Weems, show that the remaining organic material is left in forms much more readily broken up than those in the fresh sewage. In addition, there is usually, though not always, a material reduction in the tank of the bacteria In the sewage. The benefit resulting from the tank is probably even greater than indicated by the chemical analyses, because the albuminoid ammonia process probably detects a much larger per cent of the partially decom- posed organic matter in the tank sewage than it does of the organic matter in the sewage before it enters the tank. On the average the sewage remains in the Ames tank about six to seven hours, as compared with 24 to 36 hours in the ordinary septic tank. Perhaps partly on this account and partly on account of the fact that escape is provided for the gases of decomposition, which in the case of septic sewage have been found injurious to the purifying organisms of the filter beds, we have had no difficulty in establishing nitrification and satisfactory purification in the filter beds, although we work them at the rate of over 100,000 gallons per acre per day, as compared with 60,000 gallons used by the Massachusetts State Board of Health for crude sewage on a filter of similar material. In this connection it should be noted that the Massachusetts filters rest one day in seven, while at the College during 3% months each year the filters receive only about one-fourth the full amount given. —13— The author would like to triple the size of the settling chamber of the College' plant to see whether the amount of sludge could not be decreased, and the rate of filtration still further increased. The author would also like to have a couple of "bacteria beds" constructed, so as to compare their efficiency with that of the intermit- tent filter beds. A feature of the original plans which was omitted in construction was a pipe line extending east across a level field, with hydrants at short intervals, from which sewage could be drawn for irrigation. It is desired still to add this feature, and then to inaugurate experiments as to the exact value of sewage in irrigating various crops. This work wouM be done in co-operation with the Iowa Agricultural Experiment Station, which is located at the College. The conditions at the College are more favorable for securing exact data as to the fertilizing value of sewage, and as to the kind of crops best suited to sewage farms, than at any other place known to the writer. At;ention should be called to the fact that the College water supply Is taken from a well 2,215 feet deep. The successful operation of tue College sewage disposal plant proves that Iowa towns using deep well water can be certain of success in sewage purification. This is likely to be of importance to many places. In examining the results of the chemical analyses, as given by Professor Weems, it should be under- stood that the "solids" consist mainly of mineral compounds found in the deep well water, and that the effect of these compounds on the "oxygen consumed" is as yet unknown. In collecting the samples for the bacterial and chemical analyses described by Professors Weems and Pammel the fact that the sewage is collected in the flushing chamber, and discharged only at intervals, was taken advantage of in endeavoring to secure fair average samples of the sewage. In their descriptions the "manhole" sewage is fresh sewage, collected in the manhole just before entering the tank. Sam- ples of this were taken when the flushing chamber was about one-half full, so as to get as fair an average of that particular discharge as possible. In collecting the sample the inflowing sewage was dipped at a rate which gave the desired amount in about five minutes. The "tank" sewage is the sewage as it fiows on the filter beds. The sam- ples of tank sewage were collected at intervals during a period of about fifteen minutes at the middle of the discharge. The required amount was taken through a faucet in a small pipe which terminates in the middle line of the discharge pipe near the tank. The samples of eflluent were taken at a sufficient length of time after the discharge to come at about the middle of the main efl[iuent flow. From the methods of collection it will be seen that the samples —14— of "tank" sewage and effluent are more reliably representative than those of "manhole"' sewage. The manhole sewage fluctuates greatly in quality, but the variations must largely disappear in the mixed tank sewage. We have planned a series of analyses to determine the hourly and daily variations in the quality of the sewage, and we caution read- ers that the reports given in these papers are merely preliminary. For that reason the detailed records are reserved until a greater mass of data has been accumulated. Professor Weems has also planned in- vestigations as to the effect of the mineral matter in the deep well water on the amount of "oxygen consumed." We have also planned investigations to determine the quality and best methods of purification of the creamery sewage by Itself. THE CHEMICAL INVESTIGATION OF THE COLLEGE SEWAGE PLANT. By. J. B. Weems. In connection with the chemical work in the investigation of the sewage plant of the Iowa State College it may be well to say that the methods used were those recommended in the Massachusetts reports on this subject, in order that a satisfactory comparison might be made if this is desirable at any time. The samples were collected each week and as soon as collected the analytical work was begun upon them. The distance between the plant and laboratory is not very far and so only a few minutes passed be ore the samples were being analyzed. The determinations made were of free ammonia, the so-called albumin- oid ammonia, chlorin, solids, nitrites and nitrates, oxygen consumed in fifteen minutes and four hours respectively. The sewage as re- ceived from the different parts of the plant is very concentrated and it is also noticed that the sewage varied in the samples received, accord- ing to the temperature and rainfall. Samples were received from three sources each week, i. e., the manhole, an arrangement made to receive the sewage before it enters the other parts of the plant. The tank furnished the second sample, and the effluent the third. Before proceeding to the consideration of the results on the sewage it may be well to call attention to the chemical composition of the water from the College well. Most of the deep well waters of the state have large amounts of free ammonia and solids, and with the solids a large amount of chloi'in as chlorids is generally present. This condition —15— would naturally lead us to expect that these substances would be found in excess according to the nature of the water supply. The sanitary analysis of the College well water is as follows: Sanitary Analysis. Parts per Million. Free Ammonia. 1.2 Albuminoid ammonia Trace Solids 125S. Nitrogen as nitrites Trace Nitrogen as nitrates Trace The mineral constituents present in the same water are as shown in the tables given below: iVilneral Analysis. Parts per Million. Silica (SiOa) 3.000 Alumina (Al jOa) 7.000 Ferric Ox id (Fe 2O3 ) Lime (CaO) 49.3OO Magnesia (MgO) 24.300 Soda (Na'jO) 526.800 Chlorin (CI) 203.800 Sulfur trioxid (SO3 ) 429.700 Carbon dioxid (CO .,) 118.800 Water in combination 17.600 Total 13S0.000 Less oxygen replaced by chlorin 46.000 Net total 1334.300 Probable Combinations. Silica (SiOa) 3.000 Alumina' (AI2 O3) 7.OOO Ferric oxid CFeaOa) Calcium Bicarbonate (CaH2((C0 s'a) 21.700 Magnesium Bicarbonate (MgHjlLOs).) 88.200 Sodium sulfate (Na.SO ,) 763.000 Sodium clilorid (NaCl) Sodium acid Carbonate (NaHCOs) 40.600 Calcium Carbonate (CaCog) 74.500 Total 1334.300 To ilustrate the nature of the results obtained in the chemical investigation of the sewage a number of results are taken and grouped —16— together, and no attempt is made to give the complete record of the work here. The results are stated in parts per million. KIND OF SEWAGE u SOLIDS AMMONIA NITROGEN OXYGEN DATE > 5° J u ru ^ B bo C "^ .2 1 ° < IN 1899. "5 mm hts Manhole Tank Effluent Manhole Tank Effluent Manhole Tank Effluent Manhole Tank Effluent Manhole Tank Effluent Manhole Tank Effluent 88 107 112 9+ 70 62 107 49 ICO 67 104 70 71 75 71 139 90 1182 1628 1709 1569 14Q8 1489 879 1086 13S3 1260 1730 1 421 1545 1670 1867 1562 1743 1147 1510 l575 1505 1420 1460 776 951 1302 1024 1x65 1635 1347 1532 1538 1752 1443 1702 1040 1409 1554 I 0; 1265 1307 604 794 1221 950 1026 1606 1212 13^5 1419 1356 1441 367 12.3 0.20 1:5.6 16.8 0.72 49-7 18.4 0.3 56.5 36.5 0.9 16.6 19.2 0.94 16.3 28.7 1.08 22.8 14.6 0.22 '0-3 14.1 0. 6 ^0.6 19-9 0.66 22.7 20.9 0.62 9.6 6.0 0.96 7.4 0.58 0.16 0.2 0.4 I.O I.O 0.12 0.4 O.I 0.4 0.4 t t 10. 6.0 TO.O 0.2 t 8.0 8.0 •0 5.0 81.6 6.4 = 6.0 38.4 .7.6 105.6 83.2 9.6 I-!6.0 78.4 9.6 16.0 40.0 4.8 35.2 134.4 4.8 T29.6 177.6 44.8 2C4.8 210.2 43.2 206.4 56.0 145.6 174.4 51.2 251.6 198.4 12. s June 15 August 17 Sept. 19 Oct. 17 Nov. 14 For the examples to illustrate the chemical work I have taken one sample for each month for six months. In making a study of these examples it will be seen that the free and albuminoid ammonia are always high and the amounts present vary between wide limits. The results for the sample from the manhole must be taken as representing the condition o' the fresh sewage of the College during the time it was taken. The tank and effluent, however, will give a much better Idea as to the condition of the entire quantity of sewage, while the total quantity of ammonia present in the samples will give one a gen- eral idea in making the comparison between the condition of the sub- stances present in the sewage ana which furnished the ammonia. It has been found that the ammonia in both the free and album- inoid condition has been given from the samples in the manhole, 01 the fresh sewage, and in many cases it was out of the question to de- termine the point where the free ammonia ceased to be given off and where the reagents should be added for tne determination of the al- buminoid ammonia. For illustrating this condition the amounts of ammonia foun:l in the free and albuminoid state from the sample of June 14, 1899, may be taken. The total quantity of free ammonia for the manhole in this —17— sample of sewage was 55.6 parts per million, for the tank 16.8 parts and the effluent .72 parts, and these amounts were obtained in tubes as follows: ^"'fife':"* Manhole. Tank Effluent. 1 ' 31.5 11. . 3 3 2 7.5 3 \\y^'.'.'.'.'.'.'.'.'.'.'.'. '.S 3 3 1.2 2 * 2.2 8 2 5 1.0 5 6 1.2 5 7 1.0 3 8 7 2 9 7 2 10 8 11 1.0 12 8 13 5 14 S 15 1.0 16 1.2 17 8 IS 8 In the above example the direct readings of the tubes are given and it is not attempted to show any of the actual results in the sense of including the calculations. It will be noticed that the process for making a determination of the free ammonia in the manhole was stop- ped on account of the fact that there was no sign of a decrease in the amount, or rather of reaching the point where the tube would contain no ammonia, and this was after distilling eighteen tubes or a total of 900 cubic centimeters of the distillate. It will be noticed that after the reading of the tubes reaches about 1. there was little or no change in the case o' the manhole, while in the sample from the tank four or five tubes are sufficient to complete the process after the readings of the tubes reach this point. We have had as a general condition, no trouble in reaching this point in the work on the samples from the tank and the effluent, but with the manhole, it has been generally the opposite, and in most cases it has been found that ammonia continued to be given off after reaching the eighteenth or twentieth tube. Prom this it is readily seen that the material in the tank is much more readily acted upon by the chemical reagents in the process than that in the fresh sewage. Another matter of interest in connection with the comparison of the material in the manhole and tank samples is that of the changes taking place during the heating of the solids. In heat- ing the solid residues from these samples to i85°F it is found that the residue from the manhole has a large amount of carbon or similar material; the residue of the sample from the tank at this temperature is genei-ally nearly white or greyish in appearance. The difference in the manner of giving off the ammonia and the changes which the solids undergo during the heating process show that during the stay 18— of the sewage in the septic tanli there is a change which the material passes through, which renders it more readily acted upon by the chemical reagents and heat, and probably more easily changed by the organisms present in the filter beds. It appears from the examples given that the College sewage is in a more concentrated form than is usually to be expected and with this condition present the natural question which would present itself would be of the nature of the efficiency of the beds for purifying this material. As regards the presence of free ammonia we find that the effluent has a lower amount than is present in the water from many of the deep wells of the state. Regarding the presence of albuminoid ammonia it will be noticed that in examples presented the amount present on May 10 was .22 parts; June 14, .36 parts; August 17, .66 parts; September 19, .62 parts; October 17, .96 parts, and November 14, .58 parts. Naturally the effluent would be condemned as a potable water on account of high amount of albuminoid ammonia, but the sample of May 10, having .22 parts of albuminoid ammonia would al- most pass the requirement placed as a limit by the Iowa State Board of Health, that of .15 parts of albuminoid ammonia for surface waters. The following results taken from the reports of the Massachusetts State Board of Health may be used for comparing the effluent of the College filter beds with results from other sources. Yearly Averages of Mass. Filter No. 6. Parts per Million. Gallons per Acre Ammonia Nitrog-en as Oxy- g-eii Bacteria Year Daily Six Days per Chlorin Con- sumed per Cu. Cent Week Free Al. Ni- Ki- trites trates 18S8 39500 47.1 0.90 0.13 0.02 7.05 3033 1889 . 41000 46.1 0.06 0.09 0.00 14.20 520 1890 . 55200 54.5 0.10 0.18 0.01 12.35 "i'.o" 7969 1891 . 61200 73.0 1.73 0.30 0.03 13.36 2.6 6473 1892 . 46900 84.2 7.05 0.44 0.32 16.17 4.0 fi'in 1893 . 85500 73.9 4.S2 0.61 1.00 21.90 4.2 11790 1894 . 54300 98.0 1.78 0.47 0.98 29.80 4.3 10730 1895 . 57600 109.6 7.27 0.70 0.80 25.4 5.4 20884 1896 . 56800 104.9 6.07 0.65 1.27 27.3 5.8 21200 1897 . 60500 80.9 4.09 0.58 0.38 28.2 4.1 11700 1898 . 65600 70.6 2.21 0.41 0.16 27.3 3.5 3472 It will be seen that the College results compare very favorably. Filter No. 6 has practically the same kinu of filtering material as the College filter beds. These results as a whole must be regarded as preliminary, and there are many problems to be investigated in order to meet many questions which naturally present themselves. The analysis of the water of the deep well which supplies the College with water is pre- — 19— seated here more as representing to a certain extent the water used for the College in a general way. Quite often, however, water is used from the College spring, which is much lower in solids, chlorin, etc., and this will account for the low amount of solids and chlorin found in the sewage at certain times. In presenting this preliminary report I must acknowledge the work of Mr. J. C. Brown, assistant in the Department, and to whom all of the analytical work has been en- trusted. BACTERIOLOGICAL STUDY OF THE AMES SEWAGE PLANT AND SOME IOWA WATER SUPPLIES. By L. H. Pammel. The general acceptance of the germ theory of disease by physi- cians and sanitarians has caused the public to give an increased amount of attention to the subject of the disposal of sewage and the use of pure drinking water. The question is not only one of great import- ance to the large cities where unusual amounts of water are con- sumed, but smaller cities and even villages are considering the advis- ability of establishing adequate plants for the disposal of sewage. In Europe, especially the continental countries, Germany and Switzer- land, are far in advance of America in the matter of sewage disposal. The eastern cities are far in advance of our western cities in this mat- ter. Rafter and Baker' in an admirable treatise on the subject state "Sewage disposal, in its practical application, is comparatively a new subject in the United States; but the rapid growth of population with its movement into cities and towns, has led to a large number of cases throughout the country in which sewage is discharged into streams, ponds or lakes, which are also the sources of public water supplies." James Puertes" has shown in a very graphic manner that more than 75 per cent of the total population of European cities included in this study are supplied with water of a better quality t^an that from impounding reservoir supplies, of which New York is typical, while In the United States more than 75 per cent are supplied with water of a poorer quality than that from impounding reservoirs. The death rate from typhoid fever can only be diminished by introducing effective sewage plants and providing the people with pure water. Many small municipalities in this country have not only estab- lished a system of water works, chiefly for fire protection, but they are seriously considering the question of good potable water for do- mestic purposes and an adequate system to dispose of the sewage. The very success ul experiments of the Massachusetts State Board of Health" have encouraged the smaller municipalities to use the same 1. Sewage Disposal in the U. S., New Yorls 3, 1S94. 2. Water and Public .Health, 22-35 (Second Ed). 3, Special Report Mass. Board of Health, 1888-9. —20— methods successfully operated there for a number of years. In the paper by Professor Marston will be found the details of the plant used at the College. Reasons for Bacteriological Examination. It is only during the last quarter of a century that any attention has been given to a study of the micro-orga:nism of water. The labors of Pasteur and others set at rest the vague theories of Liebig in regard to fermentation and the part micro-organism played in the changes which were observed. Later an undue amount of stress was laid on the bacteriological examination of waters. One writer, John C. Thresh' says: "The presence of dead organic matter may be chemically demonstrated, but inasmuch as the nature of this organic matter, whether poisonous or inocuous, is beyond the power of the analyst to reveal, it is obvious that the results of a mere chemical analysis, may often be worthless or misleading." Percy Frankland- says: "Indeed, the detection of specific pathogenic bacteria in drinking water is now known to be almost beyond the range of practical politics, and the search for such bacteria is in general, only carried on in deference to the special request of the layman, the uninitiated, or the hopelessly ignorant, whilst it cannot be repeated often enough that any feeling of security which may be gathered from the unsuccessful search for pathogenic bacteria is wholly illusory, and in highest decree dangerous. By far the most important service which has been rendered by bacter- iology in this connection is the means of controlling the efficiency of filtration and other purification processes." Great advancement has been made in a bacteriological study of water and sewage in the last fifteen years. Today 'the subject is generally worked up from the chemico-biolosical standpoint. The early attempts at a bacteriological examination were o" course very crude. Among the early writers who investigated the question mention may be made of the work of Cohn' and Radlkofer*. The microscopical method employed by these writers is not without its value, especially when dealing with large microscopic organisms like animals' algae, and fungi. The early meth- ods have been greatly improved upon by Kean^, Sedgwick" Rafter', and others. For the very successful determination of these 1. Water and Water Supplies, 160. 2. Jour, of the Sanitary Institute, 20:392. 3. Beiu-age zur. Blologie d. Pflanzen, 1:108. 4. Zeitschr. f. Biologie, 1:60. 5. Science, 1889; Feb. 15 6. Rep. Mass. State Board of Healtli, 1890:803. Jour. N. Eug. Water Works Association, 1889: Sept. 7. Fi-oe. Hochester Acad. Scl.. Pt. 2, 1E90. —21 — attention may be called to the ijapers toy Parker' The successful early attempts at making microscopical examination of sewage were carried out by Beale", who studied the constituents of sewage in the mud of the Thames. In the mud examined he found the several constituents of human faeces, starch granules, fragments of vegetable tissue, etc. Sorby", another English writer, made an examination of sewage discharge, giving a quantitative method for determining the amount of impurity. The microscopic me';hods as applied to water and sewage so far as the bacterial contents are concerned are at best crude and unsatisfactory. The Use of Modern Bacteriological Methods. The subject has been approached from two sides. (1.) The dilu- tion method, which consists in diluting the liquid containing the organ- ism, then dividing the diluted material again, repeating this process as often as may be required to meet the paiticular case. The tubes of flasks of the last dilution should contain only a single germ. This is a somewhat laborious process. For some kinds of work, especially for a qualitative study of the bacterial contents of certain species, this method must be resorted to. It has been used most successfully in the work of Jorgensen and Hansen in their zymotechemical work and Miquel' has employed it for quantitative work in France with good results. Now, however, he employs what he calls the mixed process. This process is not essentially different from that now generally em- ployed. (2.) The method of plate cultures first introduced by Koch marKs a distinctive advance in bacteriological work. This method is the one. now generally used. In this method, a known quantity of water or sewage is collected in sterilized tubes. A fraction of a cubic centimeter is put in melted agar or gelatine, and this is then poured out on plates. It is then put away to allow the germs to develop. In sewage it is necessary to take a known quantity of the sewage and dilute it with sterilized water. One dilution is usually sufiicient. In our work we have uesd the plate method and as a medium agar-agar has generally been employed. Bacterial Contents of Drinking Water. A great many waters have been examined from a bacteriological standpoint. The data which have been obtained are valuable, but they do not give us all the required information of what constitutes a really potable water. There are so many sources due largely as the 8. Rep. Mass. Sta. Bd. Health, Pt. 1, 1890:581. 9. Jour. Eoy. Mic. Soc, 4:1; 1884. 10. Eep. of a Mic. Investigation of Thames Muds. App. C. B. Rep. of Roy. Cora, on Met. Sew. Discharge. 1. Ann. de. 1 Observatoire de Montsouris. 1877-1890. —22— Franklands' say, to the manner of collecting the samples, "which in most cases have been collected irrespective of whether the pump had been in operation or not." According to the Franklands a well sunk in the chalk in Kent, England, had only seven germs per cc. on the day of collection, after standing three days there were 495,000 per cc. Long standing, however, reduces the number very materially as I have shown''. In one sample of well water examined after three months and during the interval kept in a refrigerator, the number dropped from 7804 in May to 4000 in August. Some bacteriologists limit the number to 40 or 50 per cc. Some place the limit at 1000. Gruber" makes certain Qualifications, stating that no definite rule can be laid down. It is more important to consider the quality than quantity. Fecal and putrefactive bacteria should at all times be avoided. Quantitively the contents of the same well are subject to wide variations. Rubner'' gives the bacterial contents of a certain stagnant well at Marburg as follows: On July 10, he obtained 850 germs per cc. On August 25 the same well had 1620, the highest number recorded for the year. The following results show the varia- tion existing in wells in this country: Location of Well. No. of Bacteria per cc. Well No. 2. LaCrosse, Wis. (l'ammel)5 .. 5725 Well N. 4. Lacrosse, Wis. (Pammel) 7804 Well No. 5. LaCrosse, Wis. (Pammel) 1345 Well 15 ft. deep. Mass. (Sedgwick & Prescott)" 204-526 Well nortli of Agrl. Hall 20 ft. I. S. C. (Blanclie) 32600 Well Farm barn I. S. C. (Waterliouse) 480 Well Veterinary Hospital Barn 250 Well Ames E. Livery Barn (Elmina Wilson [1350 1565, 1772] average 1562 The well north of Agricultural Hall had large open ■epaoes between cover planks and soon a'ter taking samples became dry. Spring wa- ter is usually excellent, especially such as comes from our Iowa drift soils. Too frequently, however, springs are open and during rains receive the surface washings. Local conditions may frequently mod- ify the germ content in various ways. 1. Micro-Organisms in Water, 102. 2 Proc. la. Acad. Sci. Pt. 4. 1:94. 3. Die Bacteriologischo Wasserruntersuchnng u. ihre Ergebuisse. 4. Beitrage zur Lehre von den Wasserbacterien Archiv. f. Hygiene 11:365. 5. Proc. la. Acad. Sci. Pt. 4. 1:94. 6. Rep. Mass. Sta. Brd. Health, 26:437. -23— Source of Supply. No. of Uacteria per cc I. S .C. College Spring, Iowa tPammel)i 66 I. S. C. College Spring from creamery hydrant (Pammel)i 320 Open Spring No. 1 Mass. Edge of meadow (Sedgwick & rres.)2 252-258 Grown in Gelatin. Open Spring No. 3. iMass. base of meadow of woods and hills( S. & P.) ^ .... 92-105 Spring Upper Greens and near Reigate, Eng. (Franldands) i 8 Spring in Zurich. Switzerlaid. (Cramer^ i 9-3425 Deep Wells. The microorganisms of deep wells of this state have not been generally investigated. So far as they have been studied the water contains a small number of germs and none are pathogenic. Prom the nature of the case these wells should furnish water reasonably free of bacteria. The following table shows the result of our investiga- tions and those of others: Location of Well. No. of Bacteria per ec. Deep well 116 ft. Berlin, Wis. (Eussell)5 . 30 Deep well 2215 f . Anjes. (Pammel)'i 50 Deep well 2215 ft. Ames. (Fay) 50 Deep well 2215 ft. Ames (Smith) 23 Deep well tubular 193 ft., Cambridge, Mass. (S. & P.)^ '. . .2J4-269 Deep well tubular 213 ft., Boston, Mass. (S. & P.) 130-140 Deep well tubular 750 ft., Soxbury, Mass. (S. & P.) 38 Deep well tubular, Bath, Eng., Kent Co., 1888. (Frankland)a 4-47 An examination of our deep well water shows that it does not differ essentially from the results obtained at other points. Further- more it shows but little fluctuation. The well has been examined at various times since it has been in operation and during the process of boring. The results of a bacteriological examination during the progress of the work and before the waier was regularly pumped are 1. Proc. la. Acad. Sci. 1. c. 2. Rep. Mass. State Brd, Health. 26:436. 3. Micro-Organisms of Water, 107. 4. Die Wasserversorgung von Zurich. 1885. 6. Rep. Wis. State Brd. Hea.fj. 17:107. 6. Proc. la. Acad. Sci. 1. c. 7. Rep. Mass. Sta. Brd. Health. 26:440. 8. Micro-Organisms of Water, 106. —24— here given. Mr. Damon by a simple apparatus succeeded in making a qualitative analysis at different depths. No. of Bacteria per cc. Depth First Determination Second Determination 26080 3 500 10 300 1870 15 430 20 1160 255 25 2246 40 650 75 470 440 100 600 500 150 350 260 400 650 650 500 300 250 600 650 780 1500 1250 The large number at 1500 feet was due to sediment and dirt which collected at this point where the men had to work a long time repairing the machinery which broke during the operation. The well was left open before the time of regular pumping, dust and dirt had accumu- lated, and hence the large number of bacteria present, at all points. The water obtained from Iowa rivers has received only casual study. Mr. Steelsmith in the writer's laboratory found the following in the Iowa river at Marshalltown. During the examination there was an epidemic of typhoid fever. A large majority of liquefying species Source. Xu. of Bncteria per cc Water above mill dam June 7 (Steelsmith) 2170 Pumping Station June 7 (Steelsmith) 1200 Hydrant Dr. Mieghle's office (Steelsmith) 1800 Avg. from six hydrants September 9 (Steelsmith) 2040 Avg. from sixteen hydrants October 17 1900 were found. We also detected B. coli-communis. This undoubtedly came from the sewage which entered the river above Marshalltown water works. The writer has also reported on the bacterial contents of Miss- —25— issippi river water at LaCrosse" Wis. To tliese we may add also a few other determinations made at Ames. No. of Bacteria per cc Hydrant, Fourth street, LaCrosse, Wis 4000 Direct from Miss, river Z 3000 Squaw Creek* Ames, October 3 (Waterliouse) 1000 Squaw Creels, Ames, August 3 (Blanche) 650 Squaw Creek, Ames, September 6 (Blanche) 840 'Among the germs isolated from Squaw Creek was one pathogenic to mice. The number o: germs found in river waters at other points is in- dicated in tlie following table: No. of Bacteria per cc Elver Main above Wurzburg (Eosenberg)i 520 Elven Dre above York (Frankland)2 33400 Elver Ure above Eipou (Prankland) 1800 River Llmant, Switz., Zurich Stadmulle (Schlatter)3 Jan. to Feb 200-1900 Elver Spree, Berlin Water Works, Apr. to Mch. (ProsKaner)* (May) 750; (Apr) 17000 Elver Seine at Ivry (Miquel)5 (Aug.) 67S0; (Dee.) 7S950 Elver Thames at Hampton (Frankland)i> 18S8, (July) 1070; (Jan.) 92000 Elver Merrimac .Mass., (Clark)r 1896 8700-10900 River Merrimac, Mass., (Clark)? 1897. Avg. for Apr. 3768; (Sept.) 14445 River Potmae very turbid (Smlth)'J 18S6 10000 Elver Potomac very clear 150 Elver Mohawk below Mill Creek (Brown)io March 8, 1892 16388 Elver Mohawk, Rome Water Works (Brown), March 3 42 River Hudson, Troy, west side (Brown)" flood tide Jan 1950 Elver Hudson, Troy, west side (Brown), ebb tide, February 5 904 Stagnant Pools. While many farmers have provided their live stocli with a good pure water from deep tubular wells, some still depend upon the stag- nant water which collects in artificial basins. In these there is a real element of danger to live stock. Not only do such basins contain refuse' from barns, but other refuse from yards, and frequently from 0. Proc. la. Acad. Scl. Pt. 4. 1:94. 1. Archlv. of Hygiene, 1886:448. 2. Micro-Organlsms of Water, 100. 3. Zeitsch. of H.vslene, 9:56 4. Zeitsch. of Hygiene, 2:401. 5. Man prat. d'Anaylse bact des Eaux, 132. 6. Mlcro-Organisms of Water, 90. 7. Eep. Mass. State Brd. of Health, 28:507. 8. Rep. Mass. Sta. Brd, 9. Popular Health Mag., 1:252. 10. Eep. N. Y. Sta. Brd. Health, 13:684. 1.1. Rep. N. Y. Sta. Brd, Health, 13:688. —26— poorly constructed privies. Dr. Stalker'- has called attention to disease in live stock originating from contamination of water supply. "While I have not been permitted to make many examinations, the re- sults of three bacteriological analyses made in our laboratory are here given: Source. No. of Bacteria per cc Stagnant pond, Sept. 19 (Waterliouse) 500 Stagnant pond, Sept. 19 (Waterhouse) 1162 Stagnant pond, Sept. 19 (Waterhonse) 2500 Sewage Disposal. Sewage contains an extraordinarly large number of bacteria. Dr. Sedgwici 1 states that the average of 126 bacterial analyses of Lawrence sewage made between November, 1888, and November, 1889, show 708000 per cc. The extremes were 102400 on February 27, 1889, and 3963000 on April 16. The numbers were comparatively high in April, May and June, and comparatively low from December to April. In the old College sewer the number of bacteria found in sewage was as follows: June 14, sewage water contained 6886 (Blmina Wilson). On September 25, it was found to contain 6120 bacteria per cc. Gas pro- ducing bacteria as well as Sarcina aurantiaca were abundant. Dr. Frankland^ in his report on the number of bacteria found in Dee sewage states that from 23,500 to 26,000,000 germs were found in the effluent of the Ballater sewage pond. Prausnitz" found 227,- 369 germs in the Isar river near the entrance of the principal sewer. According to Frank* the Landweber canal, which receives the sewage of Berlin and thence empties into the river Spree contained ps much as 1,392,000 germs in June. Various methods of sewage disposal are used. (1) Self purifica- tion, which is fairly effective only where large bodies of water occur. This purification is due not only to sedimentation and dilution, but to important biological changes going on between plants and animals. (2.) Chemical precipitation. By this process it is attempted to carry away certain insoluble precipitates which under favorable conditions may carry away some of the dissolved matter. (3.) Irrigation pur- poses. Geo. E. Waring' was a great advocate of this system. This has been discussed by Ra'ter". One important phase of the ques- tion comes under intermittent sand filtration. (4.) Intermittent fll- 12. Snme Observations on Contaminated AVater Supply for Live Stock. Bull, la. Agrl. Exp. Sta., 13:118. 1. Exp. Invent. Mass. State Brd. Healtli. Ft. 2. 1889-1890:819. 2. Micrt>-Organisms in Water, 101. 3. Der Einfluss d. Jlunchener Canalisation auf die Isar, 1889. Munchen. 4. Zeitschr. f. Hygiene, 2:401. 5. The proper disposal of s(.'\vage. Separate from Yale Med. Jour., 18D6. 6. Water Supply and Irrigation Papers. Bull. U. S. Geol. Surv., 22. —27— tration. This system has been tried sufficiently iong in this country and in Europe to commend it to sanitarians as a most important way of purifying sewage. Rafter and Baker' state that the first mention of intermittent downward filtration was made by the Rivers Pollution Commission in 1870. Many experiments have been made on the purification of sewage by sand filtration, but chiefly by the State Board of Health of Massa- chusetts^ In these classical experiments an enormous amount of work has been recorded. Prom their experiments it was found that a very efficient filter bed could be constructed with a mixture of coarse and fine sand and fine gravel, 3 feet, 8 inches In depth. Through such a filter bed only 5 per cent of the bacteria were found in the effluent. In a later report' there is a full account of the practical workings of the Lawrence city filter which has done most efficient work. The Bacillus coli-communis, the characteristic organism of sewage, was found only a few times in the effluent. The subject of bacterial puri- fication of sewage is not only a chemical process, but a biological one, and as Percy Frankland says*, "In short, we have in these bacteria beds a very beautiful piece of biological machinery, which, however, like all delicate appliances, requires careful management, and is sub- servient to the law of the conservation of energy." It used to be held by certain German investigators that these ordinary sand filters had the power of arresting all bacteria. According to Piefke and others it was held that efficient filtration was brought about by the formation of a slimy mass about the particles. This slimy mass consists of bac- teria which are the real filters. It is certainly true that in our own results the sand and gravel filters became more efficient with age. The sand and gravel was less compact at first, and I am inclined to think the filter was less efficient on this account. Puller* regards the theory of Piefke, Plugge and Proskaner, who hold that the sticky coat Ing of the surface lawers of filters is indispensable to satisfactorily re- move the bacteria, as fallacious. He points out that the surface layer removes more bacteria in proportion to the thicKness than any other layer. We have also noticed that when the surface of the filter is scraped it does not diminish the efficiency of the filter in the removal of bacteria. in order to compare the efficiency of our filter plant with that of 1. Itafter and Baker Sewage Disposal in the U. S., 228. 2. Exp. Invest. Mass. Sta. Brd. Health. Upon purifleation of sewage. Pt. 1, 2, 1S89-1S90. Kep. Mass. Brd. Health, 24, 26, 28, 29. 3. L. C, 24, 29:494. 4. Jour, sanitary Inst., 20:395. 5. Eep. aiass. Sta. Bd. Hlth., 26:620. —28— the Massachusetts "filter I insert here the results obtained by Mr. Clark' in their filter No. 6, which corresponds to our own. Averages for Montlis. 1S97 1S98 January 49000 7100 February 20200 S300 jXarcli 27500 6S00 April IISOO 3700 May 6200 2150 June 3300 9050 July 1600 669 August 1200 235 September 900 484 October 1100 410 November 109M 623 December 6500 3144 Average for twelve moutlis 11700 3472 'I'his filter received at the rate of 60,500 gallons per acre for six days in the week in 1897, and 65,600 in 1898. In 1897 the Massachu- setts results were worse and in 1898 a little beiter than at Ames in 1899, but the applied sewage was considerably weaker in 1898, and even in 1897 was weaker than the College sewage in 1899. The filter beds of the College plant cover 0.4 acre. They consist of two beds, each 55 feet by 150 feet, made of mixed coarse and fine gravel and sand averaging 4 feet deep. For a detailed description see the paper by Professor Marston. The "effective size" is from 0.33mm. to 0.38mm., and the "uniformity coefficient" ranges from 7.1 to 11.6. The sewage is applied at the average rate of about 100,000 gallons per acre per day, for about 8% months of the year, and about one-fourth this rate during the remaining time. The plant was put in operation September 15, 1898. Bacteriological analyses were made daily of the effluent, and once a week samples were collected of the fresh sewage from the manhole, and of the sewage from the tank as it flows on the beds. No attempt has been made to determine the species except incidentally. In the eflluent B. coli-communis and B. cloaceae were found during the early operation of the effluent. The B. coli-communis has repeatedly been found in the manhole and tank. We also found Sarcina vertriculi and S. aurantiaca in the manhole. The detail of collecting and determining the number of bacteria was in charge of Senior students, Messrs. O. J. Fay, J. H. Grisdale, H. S. Hopkins, Dr. A. G. Hopkins, Dr. S. P. Smith, L. Russell Walker, and (J. V/. Warburton, to whom the writer desires to express his obli- gations.* For this work plain agar-agar was mostly used. The sam- 1. Rep. Mass. Sta. Bd. Hlth., 30:483; 29:438. 'I wish also to tbank Dr. Kennedy of the State Board of Health, who gave me access to the library of the --^ .'■ 29— pies were all collected in sterilized test tubes and a known quantity of the samples was taken out with a sterilized pipette and placed in melted ajar-agar, and poured in Petri dishes. In the early work par- allel peptone gelatin plates were poured, but as these did not differ essentially from the peptone agar-agar, the latter was used exclus- Ivly. The filter bed has been under observation for more than a year. During the first two or three weeks of the operation of the filter bed the bacteria were not removed very efficiently. Prom September 15 to October 1 the effiuent had 656,200 to 1,250,800. The manhole on Oc- tober 1 had 750,000; tank, 372,000; the effluent, 656,000. Evidently biological filtration had not been operating sufficiently to remove the sewage bacteria and the filter bed was not compact enough. The ef- fiuent gradually contained a smaller number of bacteria. On November 5 there were 12,200 bacteria per cc. On December 1 the manhole con- tained 3,160,000, the tank 940,000, effluent 22,680 bacteria per cc. From December 26 to January 2, the effiuent did not run. On January 11 the manhole had 345,864, tank 31,200, effluent 8,600 bacteria per cc. The filter bed was frozen on February 9 and the effluent was not ob- tained until April 30, when it contained 4,075 bacteria per cc. May 3 the manhole had 194,956, tank 168,600, effluent 11,520. During the month of May the number of batceria in the effluent fiuctuated between 3,770 and 18,000. The efficiency of the wes; filter bed which was sam- pled much more frequently than the east is shown from the fact that the tank on June 28 contained 1,108,000 bacteria per cc, the effluent only 2,640. The effluent worked very satisfactorily during the month o£ July. The lowest number found in the effluent of the west bed was 960 on July 2. The sewage discharge was then less, owing to the Col- lege vacation. The efficiency of the east filter bed is also shown in the removal of bacteria. The manhole on July 5 had 708,000 bacteria, tha tank 814,000, effluent 1,280. On August 9 the number of bacteria in manhole ran up to 3,840,000, tank 1,240,000, effluent 3,000. Septem- ber 5 an unsual number of bacteria were found in the manhole. This high number kept up during the entire month of September. On Sep- tember 5, 9,000,000; September 12, 8,600,000; Septem'ber 19, 7,260,000; September 27, 9,600,000; on the 5th the effiuent of the west filter bed had only 600 bacteria. The effluent o the east filter bed on September 27 had 8,160. On October 3, the number of bacteria in manhole drop- ped to 4,800,000, with a few less in the tank. The effluent from the west filter bed contained 3,720 per cc. There was no appreciable change in the manhole till October 24, when the number Increased to 6,760,000. The effluent from west filter bed had 3,820 bacteria per cc. There was a continuous rise till November 7, when the number dropped to 6,800,000, the tank contained 4,350,000, the effiuent of west filter bed contained 2,040. The explanation of the rise and fall of the —30— bacteria in the manhole and tank is not far to seek. Temperature is the important factor. This is shown in the following table: Temperature Records of Manhole, Tank, Air and Filter Bed In Degrees F. Soil Te mperatures West Date ,839 Vlanhole Tank Air Filtei Eed North End Day Hour 12 in. Deep 24 in Deep 36 in. Deep Apr. 29 1 30 p ni 59 63 63.5 59.5 60 57 N a5' J it 57 61 72 60 57. 5 55.5 "13 llSp m 56.5 58 60 56.25 59.5 62.75 " 24 2 00p tn 55 56 74 58 56 57.25 Tune 3 130pra 58 60 .-0 67 67.5 67 " 16 lOOp m 63 63 94 63 64 66.5 " 24 tt 59 61 79 (5 20 pm) 69 {5 20 pm) 70 (5 20 pm) (74 520 pm) July 5 1 3ii p m 61.5 63 85 65 66.5 68 " 21 64 67 107 78 76.5 75 Aug. 10 5 00p m 69 70 92 68.5 68.5 73 "17 11 15 a m 68 67 87 68 69 69.5 " 24 S 30 p m 66 64 66 74 74 74 " 29 9 10 a m 72 71 82 72 73 73.5 Sept. S 8 45 a ra 78 77.5 89 75 75.5 75 " 12 2 45 p m 75.5 77 83 68.5 69.5 70.5 " 19 10 45 a m 68 68 72 64 64 64 " 27 2 oO p m 78 77 83 . 60 61.5 62 Oct. 3 2 20pin 71 70 73 60.5 60.5 62 " 10 2 30p m 56.5 56 54.5 60.5 60.5 59.5 " 17 8 40 a m 47 48 48 56 60 61 " 24 10 10 a m 76 75 82 64.5 64.5 63.5 " 31 2 30pm 72 71 73 53 53.5 53 Not. 7 2 20 p m 54 55 56 52 50 47 • 14 210p m 47 49 40 49 50 50 " 21 10 10 a m 56 56 54 51 50 48.5 Dec. 18 1 30 p 111 S3 48 31.5 — 35.5 38.5 There is very little difference in the number of bacteria per cc. in manhole and tank. The greater number of organisms in the man- hole is no doubt due to the solid particles contained therein which are largely removed before it enters the tank. On the other hand the tank contains a large amount of more food for bacteria and as some lime -31— elapses before the tank is discharged we can readily see that there would be a large number of bacteria. The monthly averages of bacteria in effluent of filter bed is shown in the following table: Montli, 1S99. Number of Bacteria per cc January, 15 days 9S67 February, 3 days 3450 March, days April, 1 day .' 11075 May, 27 days 8965 June, 27 days 4539 July, 31 days 2538 August, 31 days 2736 September, 30 days 3693 October, 29 days 4203 November, 26 days 2925 December, 27 days 2335 Average for Eleven Montlis 5127 This is a remarkably good showing, considering that owing to in- undations in June by heavy rains and the frozen condition of the beds from February to May, part of the results are abnormally high. These results should be compared with those of the Massachusetts Filter No. 6, given on another page.