Century West provided design and construction management services on this wastewater treatment project. This project included removing and land applying biosolids from three existing lagoons before regrading and installing a HDPE liner. Additional improvements included a new headworks facility with an auger style screening system, influent and effluent parshall flumes with ultrasonic flow measurement systems, composite wastewater samplers, UV effluent disinfection system, SCADA computer monitoring system, natural gas powered emergency generator, and autodialer alarm system. The upgraded facility incorporates diffused aeration from a central 20-hp blower that minimized electrical costs and an attached growth passive media filter for ammonia removal.
During excavation of the lagoons, groundwater springs were encountered. A new underdrain system for each lagoon was added to the project to allow the groundwater and any gasses under the liner to escape. This drain system will prevent gas bubbles from forming under the liner, which has been a major issue in other recent lagoon rehabilitation projects.
The $2.1 million project will bring the Town’s WWTP into compliance with its NPDES permit. The project was funded by a Washington State Department of Ecology Centennial Clean Water Fund Grant and State Revolving Fund Loan, and Community Development Block Grant.