S.M.U.D. East Campus

Project

Sacramento Municipal Utility District Greywater for Toilet Flushing

The Sacramento Municipal Utility District was designing a new 51-acre East Campus Operations Center that was to be “green” in every way practical. According to Gary King, chief workforce officer at SMUD, “The project will serve as a nationwide model for customers and public utility leadership peers in the ongoing sustainability movement.”In addition to photovoltaic and thermal solar panels to provide a source of on-site renewable energy, planners wanted to make efforts to conserve water by evaluating options for on-site water reuse. Stantec Architecture and Intech Mechanical teamed up with Wahaso to evaluate and deliver the best option for a system.

Challenge

Wahaso worked with two different design teams to identify the optimal water reuse options. Possible sources included rooftop rainwater, cooling tower blow-down reuse and greywater. Sacramento’s climate is arid, and the cost of storing sufficient rainfall throughout the dry season was cost prohibitive. And there were concerns about chemicals and dissolved solids in the blow-down. Space for water storage was a real issue. Demand for toilet flushing was about 450 gallons per day with a much greater demand for irrigation water.