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Bondurant's Odor & Lagoons
By: Shelby Hagan, Administrative Assistant
Date Published: Thursday, February 02, 2012
Bondurant’s Odor & Lagoons
What’s that smell? Many of you probably smell an odor around town from time to time. The odor comes from our wastewater treatment lagoons located west of the School’s football field.
Lagoons are pond-like bodies of water or basins designed to receive, hold and treat wastewater for 32 days at a time. In the lagoon, wastewater is treated through a combination of physical, biological and chemical processes. Its objective is to produce an environmentally-safe fluid waste stream to flush down the river according to the United States Environmental Protection Agency’s (EPA) regulations.
The City has taken a number of actions in the last several years to improve the operations of the wastewater lagoons. Over $400,000 has been spent on improvements to the lagoons since 2006. Non-winter discharges have not been a problem for the last couple of years. Unfortunately winter discharges continue to be a challenge. Once ice forms on the ponds, treatment effectiveness deteriorates because the wind action and aeration are less effective.
Due to our less than normal Iowa winter, the odor around town is the result of the lagoon “turnover” due to the constant fluctuation of the temperature. In order for the odor not to occur, the weather either needs to be really cold or really hot. If you are not familiar with the natural process of “turning over”, water is most dense at 32 degrees Fahrenheit and therefore as ice melts, the cold water sinks resulting in warmer water (less dense), being displaced from the bottom and rising to the surface. Along with the rise of water, is an increase in organics including some odorous gases such as sulfides. This natural condition is why waste treatment facilities are often located on the outskirts of towns.
Want some good news? The wastewater lagoons will be taken out of service in the Fall of 2013 when the Des Moines Wastewater Reclamation Authority sewer line is extended to Bondurant. Once this happens and the current lagoon cells have been cleaned out, then we would not expect there to be seasonal odors associated with turnover.