A lagoon MBBR is a tertiary treatment process added to a lagoon system for the purpose of ammonia removal through biological nitrification. Our previous blog post, Lagoon MBBR: Moving Bed Biofilm Reactors for Ammonia Removal, explains the process in detail.
Following is a video case study of Benton, Missouri. They upgraded their wastewater lagoon facility with a NitrOx Lagoon MBBR to meet their new low ammonia limits. Watch the video and read on for highlights.
Case Study: NitrOx Lagoon MBBR for Ammonia Removal
Benton, Missouri, is a small town of 900 in the southeast corner of the state, just a few miles south of Cape Girardeau. Their wastewater is treated by a three-cell lagoon system: two main lagoons separated by a berm with one lagoon divided into two cells. The lagoon system has an average flow of 83,000 gallons per day.
Like many Missouri municipalities, Benton was faced with new ammonia limits—1.2 mg/L in summer and 2.7 mg/L in winter—to go into effect in October 2019. Although otherwise providing adequate treatment, the lagoon system would be unable to meet these new limits, especially during the winter, when cold temperatures inhibit nitrifying bacteria.
The Solution: NitrOx Lagoon MBBR
Benton considered other technologies for lagoon ammonia removal, including in-lagoon media and covers for heat retention, but found them to be cost prohibitive. They opted instead for Triplepoint’s NitrOx Lagoon MBBR because:
- It is based on proven technologies—with decades of research studies and thousands of successful installations around the world.
- It is 2/3 the cost of available alternatives. Capital costs are lower because it integrates into the existing process rather than replacing it and only takes up a small footprint, which negates the need for additional land.
- It would preserve the ease of operation and low maintenance that Benton’s existing lagoon system provides. It is simple to operate, automated, self-cleaning, and flexible.
- Treatment would not be disrupted, because the lagoons wouldn’t need to be taken off-line for installation.
- It offers controlled, reliable nitrification: Because influent temperature is thermally regulated only when needed, energy costs are minimized.
NitrOx Lagoon MBBR’s Small Footprint
The NitrOx Reactor was installed between Cells 1 and 2. After BOD treatment, effluent from Cell 1 is gravity-fed to the NitrOx; flow is then returned to Cell 2 for polishing. Unlike other lagoon MBBRs, NitrOx has a small footprint and tucks into the existing site.
To provide year round nitrification, a lagoon ammonia removal process must account for cold temperatures, because nitrifying bacteria are sensitive to cold. Other lagoon MBBRs compensate by increasing biomass—adding an additional lagoon cell filled with carrier media to encourage the growth of nitrifying bacteria.
Triplepoint’s patented NitrOx Lagoon MBBR solves the temperature issue by heating the reactor influent, only when needed and just enough to ensure biological nitrification. Because the temperature increase is minor, to a target between 36.5 and 41° F, and is only required a few months per year, energy costs are kept to a minimum. Temperature is regulated automatically, too, preserving the ease of operation of the lagoon system.
By choosing NitrOx, Benton did not have to purchase additional land or media, and would be assured of year round ammonia removal to meet their permit.