Located between San Francisco and Sacramento in Solano County, California, the Fairfield-Suisun Sewer District (FSSD) services more than 135,000 residential, commercial and industrial customers over 41 square miles. Built in 1974 and updated most recently in 2010, the state-of-the-art facility consists of a tertiary waste treatment plant averaging 16 million gallons per day (MGD) with a capacity rated at 52 MGD. Sustainability is a priority at Fairfield, and energy efficient practices and technology are used throughout the facility, including a gas turbine that operates on methane produced in the digester; the turbine heat warms both the sludge for digestion and the maintenance building. They also have four 50-kilowatt (kW) wind turbines on site and approximately 30% of the consumed power is produced by an on-site solar array.

Polymer, used in thickening and dewatering processes, significantly contributes to the cost of operating a wastewater treatment plant. In addition to potential cost savings, decreasing polymer use is consistent with the sustainability practices at Fairfield-Suisun; less polymer results in fewer deliveries, less trucks and congestion on the road, and fewer greenhouse gas emissions. With both cost and sustainability in mind, FSSD trialed UGSI Chemical Feed’s Polyblend® DP800 Demo Trailer at two applications within the plant: the screw press and the gravity belt thickener. The DP800 Demo Trailer is an integrated equipment package that automatically prepares a homogenous polymer solution. It consists of the DD4 dry polymer disperser, two side-by-side 360-gallon stainless steel mix tanks, and a final solution feed pump skid.