Top: Image courtesy City of Pasco, WA

The City of Pasco, Washington, owns and operates a facility dedicated to the treatment of process water collected from local fruit, vegetable and dairy processors. Known as the Process Water Reuse Facility (PWRF), the plant comprises a pretreatment and storage facility, as well as a land treatment system. A sister facility, the Pasco Resource Recovery Center (PRRC), has two low-rate anaerobic digesters, each with a capacity of 34 million gallons, to reduce Biochemical Oxygen Demand (BOD) levels, and generate renewable natural gas (RNG) that is collected and sold to a local distributor. The second stage of treatment occurs in a greenhouse, where a group of revolving algal biofilm systems provide an environment for algae to grow, and reduce nitrogen levels in the process water. After treatment, the water is used to irrigate 1,900 acres of city-owned agricultural fields, which are leased to local growers. The city is breaking ground in late March on an expansion of its PWRF, which will be able to recycle more than one billion gallons of  process water annually from local food processors. The PRRC is a public-private partnership with Burnham RNG who built, owns, and operates the RNG facility.