The Cascadia Wastewater Treatment Plant (WWTP) at Tehaleh is a greenfield WWTP serving a new residential community east of Tacoma in Pierce County, Washington. KJ worked with Newland Communities and Pierce County (who accepted the facility for long-term ownership and operation) to conduct planning, permitting, design, and construction management of the new membrane bioreactor (MBR) treatment plant to serve the community.
The WWTP is planned to discharge to rapid infiltration basins and is built to support future plans to supply Class A reclaimed water to meet irrigation demands at the development. The MBR system is sized to allow capacity to be increased in stages from the initial 1.0 MGD of average capacity to a peak capacity of 8 MGD by adding additional treatment trains, membrane units, solids handling, and equipment, deferring major facility expansion until occupancy in the development increases.
Planning for the WWTP was developed with Newland and Pierce County and recommended an MBR facility for the greenfield construction. The MBR facility provides the community the ability to provide reclaimed water in the development for irrigation and provides for the ability to buildout the WWTP in a modular fashion. The plan also included fine screening, an influent flume, 4-stage Bardenpho process, UV disinfection, final effluent pumping, aeration and membrane scour blowers, chemical addition for nitrogen removal, site development including a stormwater system and a Lab and Operations Building. The biggest challenge with the facility plan was how to phase the construction of the WWTP to coincide with the buildout of the community.
Kennedy Jenks provided the process, mechanical, structural, architectural, electrical and controls design and lead the permitting process for effluent discharge, building permits and site development. Kennedy Jenks served as construction manager through the 2-year construction schedule and coordinated closely with Newland Communities and Pierce County. The WWTP has been in operation since October of 2018 and is operating successfully.