The Northwest Aerated Lagoon Wastewater Treatment Plant was placed into service in 1998 with a design capacity of 3.0 mgd to treat an influent BOD load of 5,004 lbs./day. At the commencement of this project, the treatment plant would reach its design capacity in 20 months.
Allen & Hoshall has completed the first phase of design to expand the plant to treat an influent flow of 6 mgd based on population projections. The facility was designed to accommodate future expansions for an ultimate capacity of 9 mgd and designed to meet effluent permit limits of 25 mg/L BOD and 25 mg/L TSS. The facility was designed with provisions for nutrient removal either constructed with this expansion or added in the future when Total Nitrogen (TN) and/or Total Phosphrous (TP) limits are included in the NPDES permit.
The design consists of an influent pumping station after the existing screw lift pumps; mechanically cleaned bar screens; grit chamber; two oxidation ditches; two final clarifiers; return sludge pump building; solids handling building with laboratory, one 2 meter belt filter press, belt conveyor, polymer feeder, maintenance shop and appurtenances; gravity sludge thickener; and odor control system.
Allen & Hoshall also provided on-site resident inspection and construction administration services.