Sumner Regional Wastewater Treatment Facitity

In 2005, the City of Sumner completed the expansion of the Regional WWTF to 4.6 mgd capacity. This facility serves the Cities of Sumner and Bonney Lake in Pierce County. The existing complete mix aeration basin was converted to a compartmentalized basin providing activated sludge treatment with biological selectors and nitrogen removal, and a new second, identical basin was also built. Turblex single-stage blowers and fine bubble diffusers were installed for energy-efficient aeration.

The project also included a new headworks with perforated plate fine screens, influent pump station, primary clarifiers, grit removal system, secondary clarifiers with dome covers, ultraviolet disinfection system, and odor control biofilter. A new gravity thickener, primary and secondary anaerobic digesters, dewatering centrifuge, and biosolids dryer were constructed for solids handling. A new control building, blower building, laboratory, and solids handling building were also constructed. Construction cost was $18 million.