K TD 1 74^ "87 AWNEX LIBRARY 086489 j^^^M fKUlCHLING^ 1 " DATE DUE 1 CC UN] LI 1 1 Thi EMIL JCl Ti Sarah GAYLORD \^T PRINTED IN U.S.A. SEWAGE DISPOSAL PLANT IN OCEAN GROVE, N. J. BY CLYDE POTTS, ASSOC. M. AM. SOC. C. E. RE-PRINTED FROM ENGINEERING RECORD, JAN. 8, 1910 Cornell University Library The original of this bool< is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004982884 SEWAGE DISPOSAL PLANT IN OCEAN GROVE, N. J, -BY O CLYDE POTTS, ASSOC. M. AM. SOC. C. L RE-PRINTED FROM ENGINEERING RECORD, JAN. 8, I9I0 One of the Sewage Tanks at Ocean Grove d„ ing Construction SEWAGE DISPOSAL PLANT OCEAN GROVE, N. J. By Clf^iPiOtts, Assoc. M, Am. Soc. C. E. Early io 1908 the StatB Board of Health notified the various summer resorts on the New Jersey eoast to cease emptying crude sewage into the waters uoder its jurisdiction^ Disposal by dihition was the method commonly used, and the sewage, in nearly every Instance, was carried to sea through Iron pipe laid on the bed of the ocean and extending oat from shore 1,000 to 1,500 ft. In conse- quence, the bathing along the coast was not at all times what it should have been, for an easterly wind was apt to return objection- able matter to the beaches. The writer was employed by Ocean Orove to prepare plans and present the same to the State Board for its approval. It was assumed that the protection of the bathing beaches from the aesthetic point of view was all that could reason- ably be expected at that time. The order of the State Board of Health did not require the treatment of the sewage along any spe- cific lines nor did itgiyeau index as to what treatments would meet with approval. The bathing season at Ocean Grove is limited practically to the months of June, July, August and September. The bulk of the summer population is also there during that period, so that the problem was more particularly one of keeping the beaches free from objectionable matter during those months. Before the installation of sewage tanks Ocean Grove had dis- posed of its sewage through a 12-in. wrought-iron pipe extending 1,300 ft. beyond high-water mark. It was believed that tanks cap- able of liquifying the sewage during the four months of the year above mentioned and disposing of the llquilied effluent through the outfall already in existence would give satisfactory results. This effluent would discharge Into deep water several hundred feet be- yond the end of the fishing pier and some hundred feet from the bathing ground so that the possibility of its return would be re^ 3 S'^nOf^ Ul UOUUQ49Q mote. The effluent would already have been broken down in the liquifying tanks and mixed, as it would be, with a large volume of salt water, any harm from its return in this liquiUed and diluted state would be problematic. Owing to the shortness of the summer season the question of operating the tanks as septic tanks received little consideration. The sewers of Ocean Grove converge in two lines to the outfall at Embury Avenue. These two sewers are known as the Broadway sewer and the Embury Avenue sewer ; the former carries about one-seventh and the latter about six-sevenths of the sewage of the Grove. The depth below the boardwalk at which the sewers dis- cbarge Into the outfall is 13.1 ft. for the Broadway sewer and only 9.4 ft. for the Embury Avenue line. It was early decided to avoid pumping if possible. The liquefy- ing tanks were to be built into the outfall and the sewage allowed to flow in and out by gravity. The problem arose as to the advisa- bility of building separate tanks for each sewer or one tank, large- ejough to treat the sewage of both, and located at the level re- quired by the Broadway sewer. This would call for building the Embury Avenue tank in which six-sevenths of the sewage would be treated nearly 4 ft. lower than the occasion required, so that it was decided to construct two tanks, one for the Broadway and one for the Embury Avenue sewage, the latter to be generally 3.7 ft. higher than the former, and six times as large. The tanks were built alongside the boardwalk and between it and Ocean Avenue. The lowest point of the Broadway tank was 22 ft. below the boardwalk or about 6 ft. below low tide. The lowest point of the Bmbury Avenue tank was 18 ft. below the boardwalk or 2 ft. below low tide. It was this depth in the sandy beach separated from the ocean by only the 32 ft. boardwalk that constituted the main problem of the construction. The sewage flow at Ocean Grove during the summer season ap- proaches a maximum of about 1,200,000 gal. per day, while the win- ter consumption is only about 300,000 gal. This variation in the flow was another problem that entered, to a considerable extent, in any scheme adopted. This variation is shown in the accompany- ing diagram. The Embury Ayenue tank has a total capacity of 260,000 gal. 5 '^:§!l^^3^J>^ ''^-, ..g^.Mgj^ n Sktbhal Puan of Influent ano EfflulnL*!*'"" r-'u : u r^©^ J^l &77»?*.Wtwr7?:;^ft7?77W^r'7EZZ i^'^H Section A-A Section B"B Details of Embury Avenue Tank r ^ Ocean /li-OTi/e !£mii/ry /lis. , ""^is — ; — ^= — , uu JLj r^fn 1 /4M/>r9"ft«<%ff''A^'''-^ Finnrriiiifill,' sM'^^i 1 1 Beach and Bathinq Orovnds g! Atlanvc Ocean Vutlatof Tank tfFi6h\nq Location of Sewers and Tanks and is divided into four compartments as shown in the accompany- ing drawing. The curves in the diagram above mentioned show graphically the detention in hours of the sewage in the Embury Avenue tank. It was thoujiht that with tanks of sufficient size to Biye a minimum detention of 10 hours the desired results would be accomplished. Reference to the diagram shows that with one of the four sections in operation the detention will be about ten hours from Oit. 9 to June 11. From June 11 to July 1, two sections would be required to give 10-hours' detention and from July 1 to Sept. 16, during the busiest season, the entire four sections would be needed. From Sept. 16 to Oct. 9. two sections could be used. These curves are based on the water consumption, with an allowance for infiltra- tion, during the years 1906-1908. The larger tank is of reinforced concrete throughout, and is provided with a small detritus chamber, 5i ft. wide and 57 ft. long, extending across the end of the four compartments, which make up the settling tank. These four compartments are equal in size and are 9i ft. long by 13 ft. wide, with an average depth of 1 ft. They are so arranged that the sewage passes "in parallel" through any one or all of them, thus enabling the time of detention to be con- trolled by the number of compartments in use. The sewage may or may not flow through the detritus chamber, entrance to the same being controlled by valves. Sludge or detritus accumulations in either compartment of the tank or detritus accumulations in either compartment of the tank or detritus chamber may be pumped to sea through the 12-in. sludge pipe. Portable pumps driven by elec- tricity are to be used for this purpose and operating floors are lo- cated over the detritus chamber. A sump leading to' the sludge drain has an opening in each of these contrete floors into which the discharge of ihe pump may empty. The space over the detritus chamber is. housed in so as give plenty of room for the operation of the pumps and at the same time furnishes plenty of room for the operation of the valves which control the flow into the different sections of tlie tank. This operating chamber is 57 ft. long, 8 ft. wide and 6 ft. high. If the sewage should ever require a higher ds'^ree of purilication than at present comtemplated it is intended to use this chamber for disinfecting. The photograph shows the tank while the roof was being placed, and also the proximity to the 7 boardwalk. Both tanks are ventilated through a flagpole set in the ground beside them. The contract price for the larger or Embury Avenue tank was $15,000, and the Broadway tank, $5,400. J. W. Heller, of Newark, was the contractor. In all, 68,000 lb. of plain steel bars were used in the construction and 1,000 bbl. of Giant cement. With the exception of the concrete girders in the roof, the tanks were built entirely of gravel obtained near the bathing beaches; on favorable occasions it was recovered by teams and drag scrapers sent out into the shallow water at low tide. The mixture used was 1:2:4. The girders were built of crushed stone concrete of the same mixture. Corrugated-steel sheeting i-in. thick, of the Wemlinger type, was used, and it is doubtful, owing to the excessive depth and close proximity to the ocean, if the work could have been accomplished without a mishap with the use of ordinary wooden sheeting. One 6-in. centrifugal pump operated at intervals easily kept down the water which entered only from the bottom. Beach sand was practically the only material encountered. An in- teresting feature lay in the fact that all the water pumped from the excavation was fresh water. Work was begun Feb. 26, and the sewage turned into the tanks July 3, 1909. An analysis was made nf a composite sample of the effluent from the two tanks on Sept. 2, by Mr. F. E. Daniels, under the di- rection of Mr. H. M. Herbert, chief of the bureau of sewerage and water of the State Board of Health, as follows : Total solids, 814 ; fixed solids, 659 ; volatile solids, 155 ; solids in solution, 752 ; lixed solids in solution, 625; volatile sol.ids in solution, 127; solids in sus- pension, 62 ; fixed solids in suspension, 34; volatile solids in suspen- sion, 28. OAriAMOUNf^' ^PHLET BINDER m