Wastewater Treatment
Mandan's Wastewater Treatment Plant receives wastewater from industrial, commercial and residential sources, treating an average of 1.6 million gallons per day (MGD). Treated water from the plant is continuously discharged to the Missouri River.
The primary objective of the plant is to produce the highest quality effluent possible while ensuring the protection of the downstream water user.
The plant is designed to treat an average daily flow of 2.2 MGD with a peak design of 5.0 MGD. It is a Class IV mechanical treatment plant constructed in 1997. The plant operates in accordance with a North Dakota Pollutant Discharge Elimination System (NDPDES) permit.
The wastewater treatment plant is staffed with a superintendent, assistant superintendent, laboratory technician and two operators. Normal hours are Monday through Friday 8 a.m. to 4:30 p.m. with one person on call every week for weekends and after hour emergencies.
Spring Odors. During the transition from winter to spring, the pond (our facultative sludge basin) can emit a strong, unpleasant odor as the normal, organic treatment process restarts.
- During the winter, ice forms on top of the pond, eliminating the oxygen supply and stopping aerobic treatment.
- During the transition from winter to spring, this pond can emit a strong, unpleasant odor as the normal, organic treatment process restarts.
- Strong North Dakota winds can cause the odor to be more prominent.
City staff and leaders continue to work on ways to mitigate the odors from our Waste Water Treatment Plant. We are always looking for an effective and economical solution, continuing to work with regulatory officials, engineers and wastewater vendors to help find ways to better this situation.
To help mitigate odors, we are currently:
- Adding T195 Mega Bugs to the pond daily. This product is meant to boost the bacterial population that will digest the sludge within the pond and reduce odors.
- We have two Solarbee mixers on the pond providing aeration.
- As soon as the ice melts, we will pump fresh water into the pond daily.
- In the fall, staff hauls sludge from the pond to be used for fertilizer. This process began in 2009, and the City hauls and average of 405 loads and approximately 2.3 million gallons from the plant!
City staff and leaders apologize in advance for the stink our facility can produce once winter ends and warmer weather arrives in our area.
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