. Water & sewage works . beams across the filter squares. Thesewage passing thru the broken stonefilters, collects in a sump at the base ofthe pyramidal bottom and runs thruan S-inch pipe to the 42-inch main drainand thence to the dosing tanks for thesprinkling filters. The rate of filtrationthru the roughing filters may be asmuch as 175,000,000 gal. per acre per dayand by stop planks the number of filterunits necessary to keep the rate down toor below this can be thrown into opera-tion. A promising method of cleaning the fil-ter units has been devised. In the base-ments of the little towers s
. Water & sewage works . beams across the filter squares. Thesewage passing thru the broken stonefilters, collects in a sump at the base ofthe pyramidal bottom and runs thruan S-inch pipe to the 42-inch main drainand thence to the dosing tanks for thesprinkling filters. The rate of filtrationthru the roughing filters may be asmuch as 175,000,000 gal. per acre per dayand by stop planks the number of filterunits necessary to keep the rate down toor below this can be thrown into opera-tion. A promising method of cleaning the fil-ter units has been devised. In the base-ments of the little towers seen in thephotograph of tanks and roughing filtersare G-inch electrically driven centrifugalpumps, which draw their supply from thedrain which carries the effluent from thesettling tanks and roughing filters to thedosing tank of the sprinkling filters. Thisconnects by a G-inch force main with eachof the 8-inch outlet pipes of the roughingfilter units. When a unit is to be cleaned Dccemher. 522 MUNICIPAL ENGINEERING. ROUGHING filters to remove solids Irani Imhoff tank effluent. Atlantu. Sew-age Disposal Plant. Imhoff tatik in left foreground. Roughing filters with gateand pumphouse next in rear. Then more Imhoff tanks, more roughing filters, andagain more Imhoff tanks. Sprinkling filter bed in background. the influent from the settling tanks isshut off by stop planks, a valve is closed,shutting off the connection with the 42-inch main drain, a valve in the 6-inchforce main is opened and the water isforced by the pump back thru the fil-ter stone from below and runs off thruan outlet channel at a level high enoughto discharge into the settling tanks. Oneor more of the roughing filter units maybe cleaned at a time. In the photograph a settling tank isseen in the left foreground. Beyond aretwo rows of the roughing filters, with in-let channel between, and the pump and gatehouse at the left end: still fartherbeyond are four rows of settling tankunits: another double row of
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectsewerage, bookyear191
