Aeration Basin (AB) Upgrades - The AB upgrades described in the October 2020 General Sewer/Wastewater Facility Plan (Plan) include repairing spalled concrete on the exterior of the AB and repairing cracking and eroded areas of the interior concrete. After structural repairs, the interior of the basins will be coated to protect the concrete and extend the life of the aeration basins for at least another 20 years. Fine Bubble Diffusers Improvements – The fine bubble membrane diffusers will also be replaced. Replacement will improve the performance of the secondary treatment process and reduce energy costs. Mixing and Actuator Replacements – The existing mixers will be replaced with a new energyefficient mixing system. Mixing of the primary effluent with the RAS will be improved to reduce the solids imbalances between the ABs. Mixed Liquor Flow Splitter – A new automated mixed liquor flow splitting system will be installed to equally distribute mixed liquor flow between the two existing 85-foot diameter secondary clarifiers when both of these clarifiers are in service. These upgrades will improve process performance and effluent water quality. Froth Spray System – The existing froth spray system piping will be replaced to improve effectiveness and increase water and energy efficiency. Emergency Power System upgrade – The existing 500-kW Emergency Generator (EG) does not have adequate capacity to serve the complete secondary treatment process or solids processes. Refurbishment of the existing EG is not feasible due to unavailability of parts. The EG does not meet current air emission standards or noise standards. The Plan recommends replacing the existing EG and switchgear with two new 500 kW EGs, each with its own automatic transfer switch and new switch gear. The pre-design phase of this project will evaluate alternatives to provide emergency power to all critical facilities at the WWTP and select the preferred alternative based on both monetary and non-monetary factors. Providing emergency power to all facilities and processes at the WWTP will ensure treatment efficiency and effluent water quality are not compromised or degraded by a lock of power during a power outage.
