Owensville Wastewater Treatment Plant
Following the issuance of a new Missouri State Operating Permit in September 2005, which placed more stringent limits on discharges to the tributary of the impaired Red Oak Creek, the City of Owensville authorized CM Archer Group to study and draft an Engineering Report to address the current and future wastewater collection and treatment needs to bring the City's waste discharge into compliance with these new regulations. In addition, Archer was tasked with: analyzing the system relative to Inflow and Infiltration (I&I); recommending ways to reduce area-specific surcharging; recommendations for economical long-term improvements to dilapidated lift stations; elimination of failing septic systems, grinder stations, and lagoons in the surrounding area. This Report provides a comprehensive evaluation of items listed above; gives recommendations for economical improvements; and considers funding options for the capital improvements.
The City of Owensville, Missouri is currently operating a Two-cell Aerated Lagoon system for wastewater treatment. The two-cell lagoon was constructed in 1963 and was improved in 1991 by adding aeration to the first cell. Flow first enters a 9.3 acre Aerated Cell and is followed by a 13.4 acre Polishing Cell. The Polishing Cell was designed to operate in series with the Aerated Cell to meet the discharge requirements set forth by the Missouri Department of Natural Resources (MDNR). The lagoon has a permitted design flow of 405,400 gpd. The treated water is discharged into Tributary to Red Oak Creek, Bourbeuse River Basin.
Upon considering several treatment options, two specific treatment alternatives were found to be feasible. Two recommendations were proposed to allow flexibility and prevent capitalization and price increases during the bidding phase. Both alternatives allow the City to make upgrades to, and utilize the existing lagoon structures and include a new influent pump station, headworks, modifications to existing lagoon and new UV disinfection.
The ultimate plan for the City of Owensville is to upgrade the existing lagoon with one of the two recommended alternatives which would include modifications to the existing lagoon basin(s), construction of a new influent pump station, headworks, and UV disinfection system.
Upon approval by the City of the reports findings, CM Archer Group will assist the City of Owensville in securing low interest State Revolving Fund (SRF) Loans from the Missouri Department of Natural Resources (MDNR). The costs will be deferred over the next twenty years and paid for through increases in water and sewer user fees. The proposed project will increase the sanitary sewer rate of an average user of 5,000 gallons per month from $12.95 per month to $23.00 per month, or an increase of $10 per month.
In order to meet the future growth and the stringent effluent limits there is a need to upgrade the existing treatment facility. It is anticipated that the proposed advanced lagoon treatment processes will meet the stringent effluent requirements with slight modifications to the existing facility.