Dual Process Highrate Filtration of Raw Sanitary Sewage and Combined Sewer Overflows

Abstract

Pilot plant studies were conducted at New York's Newtown Creek Water Pollution Control Plant from 1975-1977 to investigate the suspended solids (SS) removal capabilities of the deep bed, high rate gravity filtration process on raw sewage and combined sewer overflows. The treatment system was composed of a rotating screen followed by a dual media, and high rate filter. A continuous series of tests on dry weather (raw sewage) flows demonstrated SS removals across the filter averaging 67 percent. Tests on combined sewer overflow and average removal of 61 percent SS across the filter. Capital costs (ENR-2520) for a high rate filtration plant are estimated at $55,225 per mgd for a 200 mgd plant (757,000 cu m/day). Total annual treatment costs, including amortization, operation and maintenance charges, range from approximately $396,450 to $1,794,050 for dual treatment facilities in a 25 to 200 mgd (94,600 to 757,000 cu m/day) capacity range and $238,050 to $1,175,900 for the same capacity range of facilities treating only CSO. Comparison with alternative treatment systems show that HRF is cost competitive with conventional sedimentation facilities for dual-process or CSO treatment yet HRF has on 5-7 percent the area requirements. For strict CSO treatment, HRF is competitive with dissolved air flotation and microstraining processes.

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1979
EPA# EPA-600/2-79-015
NTIS# PB296626/5