. Public works . to thescheme used at the Imhoff tank. Sand Filters. The sand filters are two in number, toI)rovide for resting one while the other is in use. Theembankments have been constructed of clean earth, wellcompacted, and the slopes have been sodded. The earthfloors of the beds have been ridged and the 4-inch vitri-fied underdrains have been laid in the valleys. The in-vert quarter of the joints have been cemented and theremainder left open. The 6-inch vitrified pipe main draincarries the flow to a junction manhole which also re-ceives the drainage from the sludge drying bed. Fromhere
. Public works . to thescheme used at the Imhoff tank. Sand Filters. The sand filters are two in number, toI)rovide for resting one while the other is in use. Theembankments have been constructed of clean earth, wellcompacted, and the slopes have been sodded. The earthfloors of the beds have been ridged and the 4-inch vitri-fied underdrains have been laid in the valleys. The in-vert quarter of the joints have been cemented and theremainder left open. The 6-inch vitrified pipe main draincarries the flow to a junction manhole which also re-ceives the drainage from the sludge drying bed. Fromhere the combined effluents flow to the small streamabout 50 feet away. The filter medium of the sand bedsconsists of about 2J/2 feet of sand spread over 3 inchesof gravel, ,4 to J^ inch size. This gravel in turn rests onanother gravel layer J/^-inch in size, which encases theunderdrains. The construction of the sludge drying bedswas identical to that of the sand beds; the sand, however,is only about 21 inches TERCOLATING AND SPKIXKLIXi; FILTER. Costs. The total cost of the sanitary sewer system andIhe sewage treatment plant as constructed, was $6, The sewer system alone consists of 1,942 feet of 8-inchvitrified pipe in an average cut of about 7 feet, partlyrock, 12 manholes and 2 flush tanks, and cost $2,,or at the rate of $ per linear foot, complete. Thisleaves the cost of the treatment plant as $3,, orabout $ per gallon capacity of the plant. Alterations to old laterals and laying of new laterals,together with necessary traps, etc., from the buildings tothe new sewer were done under separate contract, thecost of which was $403. The plant was designed at the offices of Albright &Mebus, consulting engineers of Philadelphia, Pa., withthe authors respectively in charge of design and con-struction. The contract for the entire work was awardedto the Suburban Contracting Company, of Philadelphia,which carried out the work in an efficient and carefulman
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Keywords: ., bookcentury1800, bookdecade1890, bookidpublicworks3, bookyear1896
