ACTIFLO®: A YEAR'S WORTH OF OPERATING EXPERIENCE FROM THE LARGEST SSO SYSTEM IN THE US

The Lawrence Wastewater Treatment Plant (WWTP) was expanded and improved to accommodate the City of Lawrence, Kansas, future growth, maintain compliance with new regulatory requirements, and meet facility needs up through the design year 2020. To accommodate future projected storm flows or sanitary sewer overflows (SSO), a wet weather facility consisting of 40 million gallons per day (mgd) ballasted flocculation system was constructed to direct discharge with the main WWTP effluent to the Kansas River. The Actiflo® system, which has been in service for over a year and half, has been operated during ten peak flow storm events that lasted anywhere from four hours to 47 hours. During the first year of operation, the Actiflo® unit encountered a variety of influent flow characteristics and operating conditions. Real-time operating experience has been obtained. For each storm event, the polymer and ferric chloride dosages were optimized to enable the effluent to meet the plant's permit. This presentation will discuss the actual performance of the Actiflo® system, observations during storm events, and impacts on the existing main plant's process.