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Author      Title/Abstract      

Performance of Constructed Wetlands at Cle Elum, Washington
Author: Jordan W. Smith, Ronald W. Crites, Jim Loonard
Date: 1/102

The performance of a free water surface (FWS) constructed wetland at Cle Elum, Washington is reviewed. The wetland was designed to treat an average monthly flow of 0.7 mgd of secondary effluent from two aerated treatment ponds and achieve advanced secondary quality. An existing third pond was converted to a wetland that consists of a series of three planted zones separated by two open zones. The performance of the constructed wetlands has exceeded the requirements placed by the Washington State Department of Ecology. The effluent BOD averages 10 mg/L or 95 percent removal of influent BOD into the pond/wetlands system. The effluent TSS has been consistently around 5 mg/L, allowing the downstream ultraviolet light (UV) disinfection system to operate effectively. The disinfection requirement is 200 fecal coliform per 100 mL and the UV system averages 26 fecal coliform per 100 mL.