Wastewater treatment lagoons are the most widespread form of treatment in the United States for animal operations and rural domestic sewage. Treatment lagoons can be effective at removing BOD. They are not effective at reducing ammonia levels. Animal operations with recycled water from lagoons can experience high levels of ammonia in the water. This can result in severe odor problems and potentially toxic air quality. Removal of ammonia from wastewater requires two kinds of bacteria: nitrifiers, and denitrifiers. Nitrifiers are aerobic and thrive in an attached bio-film. Denitrifiers are anaerobic bacteria, and also thrive in bio-film. Traditional treatment lagoons provide no surface area for bio-film to adhere. Aerated Submerged Bio-Film (ASBF) consists of structures that stand submerged in a treatment lagoon. These structures provide surface area for a bio-film of the necessary bacteria. Compressed air released along the base of the surfaces allows air bubbles to rise, oxygenating the bio-film. The proposed technology is similar to traditional trickling filters, except that the oxygen is forced into the submerged bio-film, rather than wastewater pumped up to trickle down over a bio-film. This approach is much less expensive than trickling filters, and should significantly enhance the performance of existing lagoon systems.
Anticipated Results/Potential Commercial Applications of Research: The Aerated Submerged Bio-Film (ABSF) technology will permit rural communities and animal operators to retrofit existing lagoon systems at a fraction of the cost of alternative treatment technologies. The retrofitted lagoons should enhance the removal of BOD and greatly enhance ammonia removal. Existing undersized lagoons could then produce a water quality sufficient for discharge or reuse of the water in the animal operation. Improved performance of lagoons will eliminate a source of potential environmental contamination, as well as conserve fresh water supplies by allowing for reuse of animal operation wastewater.
