what we do


Engineering innovative wastewater treatment solutions

Increasing population, aging infrastructure, and stricter regulations have put pressure on wastewater conveyance and treatment systems. Parametrix develops sustainable, cost-effective solutions. In addition to traditional approaches, we are experienced in designing systems for advanced membrane filtration, reclaimed water, enhanced nutrient systems, and biosolids management. From collection and conveyance to treatment and reuse, we are exploring new ways for our clients to improve their operations and meet today’s challenges.

Cowlitz Casino Development and Water Reclamation Plant  | Parametrix
Cowlitz Casino Development and Water Reclamation Plant
LaCenter, Washington
Client: Cowlitz Tribe
Partner: Salishan-Mohegan, LLC

The Cowlitz Tribe developed a new resort casino, Ilani, to establish an economic base for the community and provide 1,500 jobs. Parametrix supported the development, which was unable to connect to the sewer system, by designing a new wastewater treatment plant and performing construction layout (survey) for the entire development. We designed an advanced tertiary wastewater treatment process using a biological and membrane filtration process followed by a combination of UV and chemical disinfection to produce Class A reclaimed water for future use at the Casino for irrigation, flushing toilets, water features, and laundry services. Excess effluent will be injected into five deep dry injection wells constructed 100 to 180 feet below the surface and above the groundwater aquifer (“the vadose zone”) capable of handling up to 200,000 gpd, a concept that had only been tried once before in the state of Washington via authorization by EPA. This was a fast track design-build project and Parametrix delivered the final construction contract package within 6 months.




"...excellent project management throughout the project to keep the project on schedule and within budget... Your staff did an outstanding job of designing the facilities and managing the construction."

Steven Schuller, PE, former City of Duvall Director of Public Works