DON'T ABANDON A USABLE FACILITY — USE IT FOR INTERMITTENT WET WEATHER TREATMENT

Treatment of wet weather flows is possible with modifications to existing primary treatment facilities in a cost-effective manner. As part of the Alki Transfer/CSO Project, King County Washington elected to modify the continuously operated Alki Treatment Plant (ATP) to an intermittently operated wet weather facility. This paper reviews the design considerations and details of the Alki Treatment Stormweather Modifications Contract along with a review of the operating status of the facility. The contract involved modifications to rectangular clarifier equipment, sludge pumping facilities, disinfection systems, basin drainage and wash down facilities, control systems, and other plant facilities.