Aquaculture, the fastest growing field in agriculture, is hindered by inherent problems associated with ammonia removal. Fish and shellfish, which produce ammonia, are highly sensitive to ammonia and its derivative, nitrite. Biofilters play an essential role in removing ammonia from water in recirculating aquaculture facilities by converting ammonia to the much less toxic nitrate. The autotrophic, nitrifying bacteria that perform this process require an attachment to solid support and a supply of oxygen for their activity. Heterotrophic microorganisms also use these factors, creating a competition where the heterotrophs have the upper hand over the autotrophic, nitrifying bacteria. As a result, aquaculture biofilters do not perform at their maximum potential and may cause stress, susceptibility to disease, and toxicity for fish.By combining microbiological and engineering approaches, a competitive advantage can be given to the nitrifying bacteria. The proposed research will provide a unique support medium possessing a higher surface area for nitrification, and it will enable the use of a novel cleaning method. The process will continuously remove hetertrophic growth while maintaining a pre-coated biofilm of nitrifying bacteria on the support medium, for maximal activity.
Anticipated Results/Potential Commercial Applications of Research::The combination of microbial pre-coating, the new support medium, and the novel washing mechanism will create an entirely new biofilter, which will increase the efficiency and reliability of the ammonia removal process. Aquaculture farms will be able to support higher animal densities, increasing water recirculation and food production efficiency, and minimize pollution in fish and shellfish farming. The new technology could also be applied to commercial and home aquaria, as well as wastewater treatment facilities.
