Water Pollution Control
The community of Ottumwa generates a number of types of wastewater that are dealt with in two different ways.
Household wastewater consists of liquids that go down the drain from our sinks, toilets and bathtubs. This wastewater goes from your home into the sewer system for delivery to the Water Pollution Control Facility (WPCF) for treatement before being returned to the river.
Stormwater is water that runs off the earth’s surface (like your yard, streets and parking lots) and CAN be sent directly back to receiving waters like creeks or the Des Moines River. The most common forms of runoff are rain and melting snow. Learn more about Stormwater Management in Ottumwa.
At the time when Ottumwa was being built, it was not uncommon to combine both of these flows, household wastewater and storm runoff, in one sewer pipe and to treat it all at the treatment facility. This creates a number of problems, the first being that the Water Pollution Control Facility becomes overwhelmed when heavy rains hit our community. The second problem is that when these heavy flows come, like after a heavy rain, the sewer system itself is not designed to carry that much flow. The result is that the system discharges or overflows into a creek or river. This is called a Combined Sewer Overflow.
Ottumwa’s Water Pollution Control Facility
Ottumwa operates a state-of-the-art wastewater treatment plant. The community of Ottumwa generates an average 6 million gallons of wastewater each day. This wastewater must be treated before sending it back to the Des Moines River. When wastewater arrives at the Water Pollution Control Facility through the sewer system, it is first screened to remove any grit and other solids that are in it. The wastewater then goes through a process of aeration and digestion, utilizing active bacteria or “bugs” to consume the harmful elements. The wastewater is then sent through a filtration and disinfection system. Finally, the treated and purified water is returned to the Des Moines River. The leftover solid material or “sludge” that is removed from the water is applied to agricultural land as a fertilizer.
Hydraulic (Wastewater Coming into the Plant)
- Average Flow 6.0 Million Gallons Per Day
- Maximum Flow 12.5 Million Gallons Per Day
Organic (Byproducts of the Treatment Process)
C-BOD – Carbonaceous Biochemical Oxygen Demand
- 9,900 lbs Per Day Average
- 13,150 lbs Per Day Peak
Total Suspended Solids (known as TSS)
- 10,000 lbs Per Day Average
- 15,000 lbs Per Day Peak
- 1,160 lbs Per Day Average
- 1,450 lbs Per Day Peak