PILOT TESTING OF HRPCT FOR CSO IN NEW YORK CITY

This paper presents the results of pilot testing of high rate physical chemical treatment (HRPCT) technologies in New York City at the 26th Ward wastewater pollution control plant (WPCP) during the summer of 1999. The US Filter/Microsep Ballasted Floc Reactor™ (BFR), the Actiflo™ from Krüger Inc. and the Densadeg 4D™ from Infilco Degremont Inc. (IDI) were evaluated by Hazen and Sawyer for the New York City Department of Environmental Protection (NYCDEP). The pilot units were treating primary effluent, which simulated combined sewer overflow (CSO) quality. Process performance was measured in terms of effluent concentration and percent removal for TSS and BOD5 as well as time to achieve full performance after start-up (start-up time).Pilot testing was successful and showed that HRPCT is a compact technology that would be well suited for the treatment of CSO. All units performed well when operating correctly, removing between 69% and 84% of TSS on average. In addition, testing provided information on hydraulic loading, chemical dosage rates, recirculation rates, ballast dosage rate, operating ranges, as well as time to full performance after start-up and sludge quality. Some of the operational aspects should be further evaluated before proceeding to full-scale design.