Technical Information for the Wastewater System

The Ashtabula Wastewater Treatment Plant has an average daily design flow of 12.0 MGD, a peak flow of 18 MGD, and maximum hydraulic flow of 24 MGD. The treatment plant was originally constructed in 1925, with major expansions in 1955 and 1970, and various upgrades the most recent occurring in 2017. The city collects wastewater from over 9,000 service connections inside the city and outside in the surrounding county areas. Our team operates and maintains the plant and collection system including 5 lift stations, an automated bar screen, and equalization basin. Wastewater personnel also perform laboratory testing, manage the industrial pretreatment program, and perform sludge dewatering and disposal.

 

Treatment plant processes include:

• Grit Removal and Screening

• Pre-aeration and Primary Settling

• Phosphorus Removal

• Activated Sludge Aeration

• Anaerobic Sludge Digestion

• Sludge Dewatering and Disposal

• Final Settling

• UV Disinfection

 

Sludge is processed by anaerobic digestion, and dewatered by means of a centrifuge. A belt filter press is also installed as a back-up to the centrifuge. Sludge is ultimately disposed in a landfill. In 2016, 592.52 dry tons of sludge was generated. The last major modification to the sewage sludge treatment system occurred on August 10, 2006. Upgrades to the digesters are planned for 2018.

​

The City of Ashtabula’s collection system includes only separate sanitary sewers, and serves the City of Ashtabula, Ashtabula Township, Plymouth Township, Say brook Township, and other locations throughout Ashtabula County, serving a total population of approximately 26,000 people. The city estimates the inflow and infiltration rate for the collection system at 2.5 million gallons per day, according to the NPDES permit application.

Local industries contribute approximately 0.207 MGD to the flow received at Ashtabula’s WWTP. Categorical industrial users discharge an average of 0.093 MGD to the Ashtabula sewer system, while non-categorical significant industrial users contribute 0.058 MGD.

​

The WWTP has an approved pretreatment program which was approved on June 6, 1986.

​

The water supply for the City of Ashtabula is Lake Erie.

 

Description of Existing Discharge

The average design flow for the Ashtabula WWTP is 12.0 MGD, but the actual daily flow based upon monthly operating report submittals is normally considerably less. Daily flow has varied between 3.6 and 5.35 MGD based upon the 50th percentile values.