IIW integrated new technology into wastewater treatment plant to give the City of Bellevue a more simple and clean process. The facility replaced a single path trickling filter plant that was hydraulically and organically overloaded with a new extended aeration activated sludge (AeroMod) system.
The IIW engineering team developed a plan to address excessive inflow and infiltration through the construction of a flow equalization basin capable of handling wet weather flows. Recent and frequent storm events following the completion of this project have demonstrated the worth of the equalization basin and flow control system.
All wastewater flow is routed through the 3rd Street Pump Station. Here mechanical screening and grit removal units remove non-biodegradable solids. Then the wastewater is transported across Mill Creek to the wastewater plant.
IIW chose non-corroding metals and plastics to construct all of the wastewater plant equipment and materials. IIW used a design of durable masonry units to minimize the effort needed to maintain the plant.
The Aeromod process is simple to operate, and there is no need for complex electronics. Sludge is aerobically digested and then dewatered by the belt filter press. Final disposal is by land application.