Marietta Wastewater Treatment

Marietta currently has 79 miles of gravity sanitary sewer lines and 13 lift stations that move Marietta’s wastewater flow to the wastewater treatment plant.

The wastewater treatment plant is designed for an average daily flow of 3.34 million gallons per day (MGD) and an 8.25 MGD peak flow. It is designed for a population of 17,940 persons and a population equivalent of 41,753 persons. The design biochemical oxygen (BOD) demand concentration is 249 mg/L and the design for BOD loading is 6,966 lbs/day BOD. The total suspended solids (TSS) design concentration is 156 mg/L with a TSS loading design of 4,358 lbs/day TSS. It was initially constructed in the mid 1950”s as a primary treatment plant with chlorination. It was renovated in 1987 to secondary treatment. The plant is currently under renovation and the future design flow will be 4.0 MGD average daily flow and 12.0 MGD peak flow.

Phase I of the wastewater treatment plant renovation has been completed. It consisted of a new raw wastewater screening facility that will be finished in phase III, a new emergency power generator, a new electric grid connection to expand electricity availability in the amounts needed by the future renovations, a new electrical building that will house a new ultraviolet light disinfection system, future space for return activated sludge pumps to be installed in phase III, future space for a high river pumping station to be installed in phase III, a new flow splitter box and the installation of a biological anoxic selector system.

Waste Water Treatment PlantPhase I was constructed by Mosser Construction and Jess Howard Electric contractors. The total engineering and construction cost was $7,417,483.80. The project received a $250,000.00 grant from the US Army Corps of Engineers for the Biological Anoxic Selector System and the remainder was financed through the Ohio Water Pollution Control Loan Fund as administered by Ohio EPA DEFA funds from the Ohio Water Development Authority.
Phase II construction is essentially complete. Phase II construction was started by PAE Construction which went bankrupt. Phase II construction is operational and is being completed by Kirk Brothers Construction and the Hartford Bonding Company. The total contract price for Phase II engineering and construction was $7,251,024.00 although this may change due to the situation of PAE going out of business, the bonding company and possibly other factors. Phase II construction is financed through the Ohio Water Pollution Control Loan Fund by the Ohio EPA DEFA with funds from the Ohio Water Development Authority.

Phase II construction consisted of a conversion of the former anaerobic digestion system into an aerobic digestion system, the installation of a thickening centrifuge, the installation of a dewatering centrifuge, a sludge load out facility, a new bump out building attached to the administration digester building, new aerobic digester blowers and controls and various assorted pumps, motors, diffusers, electric and plumbing.
Local contractors and local labor was used by both general contractors in phases I and II. The design engineering firm for phases I and II was Stantec Consulting Columbus, Ohio office who was teamed with Pickering and Associates, a local firm.

Phase III renovations are currently at 99% of final design. This phase has been separated into four separate scopes. The Phase III Scope I of installation includes the installation of new diffusers in the aerobic digestion system and has been completed. Phase III Scope II consists of the renovation of the raw sewage pump station, installation of a new automatic bar screen, new raw wastewater pumps, flow meters, controls and various associated plumbing and electrical work. The bulk of Phase III scope II will be the complete demolition and rebuilding of the raw wastewater pumping station wet well and associated long term bypass of flow from the pump station to the rest of the treatment plant. Phase III Scope III will consist of the installation of a new septic receiving facility which will be financed by an offset in the interest rates to the amount of that investment under a program currently open by Ohio EPA in order to provide benefit to the entire community and reduce pollution. Phase III Scope IV will consist of the installation of two new final clarifiers, a new UV Disinfection System, a high river pumping station, modifications to the MLSS splitter box, new return activated sludge pumping system, supervisory control and acquisition and data system and associated plumbing, piping and wiring. The estimated cost for the phase III estimates is $15,000,000.00 however that amount may change once all of the construction bids are received. Phase III scopes II and III are planned to bid in August 2016 and construction is planned to begin in October 2016. Phase III Scope IV is still under design modifications due to some value engineering proposals that are hoped to reduce costs of the overall project.

The mailing address for the wastewater treatment plant is:

City of Marietta WWTP
440 E. Eighth Street
Marietta, OH 45750

The phone number for the wastewater treatment plant is 740-373-3858

Tours may be scheduled in advance by contacting Steve Elliott, Wastewater Superintendent, at the phone number listed above.