Ten Years of Operational Experience on HRC for Remote CSO System

摘要

The city of Bremerton, Washington had been considering the use of a high rate clarification (HRC)process to treat wet weather induced flows to reduce combined sewer overflows (CSO). In December of1999, HRC pilot testing was conducted at the Bremerton West Side Wastewater Treatment Plant (WestSide) with a trailer-mounted pilot unit to test its effectiveness. The HRC pilot testing demonstrated that ahigh quality effluent could be produced even during variable influent loading conditions at constantoverflow rates of 2,310 liters per day per square meter, lpm/m~2 (55 gallons per minute per square foot,gpm/ft~2). In 2001, construction was started on a 75.7 million liters a day, MLD (20 million-gallon a day,MGD) Actiflo? facility to treat wet weather induced flows, with the East Side Treatment Plant (EastSide) scheduled to become operational in late 2001. The HRC approach saved Bremerton in excess of$30 million compared to traditional treatment plant expansion and conveyance and allowed for a fasttracked construction schedule to meet a consent decree imposed deadline.East Side was the first and is one of only a few satellite treatment facilities in the United States that isdesigned solely to treat CSOs using the HRC process. This paper reports on the operational history ofthe HRC limited use CSO treatment facility and the unique challenges this entails.