With reference to the role of biofilters in Recirculating Aquaculture System, consider the following

Question

With reference to the role of biofilters in Recirculating Aquaculture System, consider the following statements:Biofilters provide waste treatment by removing uneaten fish feed.Biofilters convert ammonia present in fish waste to nitrate.Biofilters increase phosphorus as nutrient for fish in water.How many of the statements given above are correct?

Accepted Answer

Recirculating aquaculture systems (RAS) are unique engineered ecosystems that minimize environmental perturbation by reducing nutrient pollution discharge. They are indoor, tank-based systems in which fish are grown at high density under controlled environmental conditions.A biofilter system purifies the water and removes or detoxifies harmful waste products and uneaten feed. Biofilters use microorganisms, which are capable of degrading many compounds, fixed to an inorganic/organic medium to break down pollutants present. Hence, statement 1 is correct.Ammonia is removed from an aquarium system through the use of a biofilter. The biofilter provides a substrate on which nitrifying bacteria grow. These nitrifying bacteria consume ammonia and produce nitrite, which is also toxic to fish. Other nitrifying bacteria in the biofilter consume nitrite and produce nitrate. Hence, statement 2 is correct.Biofilters are also used to remove phosphorus waste by-products generated by fish. Thus, biofilters do not increase phosphorous content in aquatic systems. Hence, statement 3 is not correct.