Ottumwa's original Sewage Treatment Plant which began operation in 1958, had one Primary Clarifier, one Anaerobic Digester, 16 Drying Beds, and a Control House. The process removed a lot of solid waste from the wastewater. In the 1970s, after the US EPA Clean Water Act of 1972 was enacted, Trickling Filters, Secondary Anaerobic Digestion, Final Clarification, and Disinfection were added, which further cleaned the wastewater before it went to the Des Moines River. A State of Iowa Certified Laboratory was started at the plant to sample and analyze the wastewater as it entered the plant, during the processes, and before it was released back to the Des Moines River.
To meet further water quality standards imposed on the City in 1989, the City began an 8 year, three-phase program to meet those standards. This included converting the Airport Wastewater Plant to a pump station, and routing those flows to the main collection system; eliminating two pump stations; major upgrades at the City's Elm St. Pump Station; and converting the City's Sewage Treatment Plant from a Trickling Filter process, to an Extended Aeration Activated Sludge Process, which became fully operational in 1998.
The Sewage Treatment Plant got a new name – the Water Pollution Control Facility, which treats an average of 6 million gallons of wastewater each day. All staff is certified and licensed through the Iowa Department of Natural Resources.
The WPCF also handles stormwater which comes to the plant through a system called combine sewers. This includes rainwater and snowmelt which runs off the streets, your yards, and parking lots. This stormwater can safely be returned to the creeks and rivers. In Ottumwa's earlier days, it was not uncommon to combine stormwater runoff with the sewage in the collection system pipes – creating combined sewers. This causes problems both in the collection system which gets overwhelmed during large rainfall events, and at the WPCF. When these combined sewers get so full, some of the flow gets discharged into creeks or the river. This is called a Combined Sewer Overflow (CSO). In an effort to eliminate these overflows, the City is in the process of separating combined sewers.
The latest upgrade to the WPCF was its Disinfection System. In 2016, Ultra-Violet Disinfection was installed, which replaced the prior method of using one ton cylinders of Chlorine gas and Sulfur Dioxide gas for disinfection.
The Clean Water Act (CWA) establishes the basic structure for regulating discharges of pollutants into the waters of the United States, and regulating quality standards for surface waters. We operate Ottumwa's Water Pollution Control Facility in accordance with federal and state law (we have a "National Pollutant Discharge Elimination System" [NPDES] Permit which states exacting requirements – Effluent limitations, Monitoring and Reporting requirements, Special Monitoring requirements, etc. which we must meet) to help ensure clean water for future generations.
Due to the COVID-19 Virus concerns, the City’s Water Pollution Control Facility has seen an increase in wipes labeled “flushable” being flushed into the City’s sewer mains. The City of Ottumwa wants residents to be aware that wipes that are sold as “flushable” are in fact not flushable for the City’s sewer pipes. Flushing of wipes causes cities to spend thousands of dollars on premature equipment repair and replacement. Wipes snag on any imperfection in sewer pipes, catch passing debris and grease, and create a “ball” that will grow to eventually plug the pipe.
