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Filtration - Classification - Biological filters
Unit 12 - Management of ponds
Filtration
Classification according to form of materialsBiological filters
Biological filtration is defined as the bacteriological conversion of organic nitrogenous compounds into nitrate. The several steps in this process are collectively referred to as the nitrogen cycle. Although the nitrogen cycle begins with conversion of nitrogen containing organic compounds into ammonia, this step usually is best completed before the material reaches the biological filter. Some ammonification and de-amination occur in all biological filters unless the filter influent is from a pure inorganic source. The primary purpose of a biological filter is conversion of ammonia to nitrite and nitrite to nitrate. This conversion is of great importance in culture of aquatic organisms because ammonia is a highly toxic metabolic waste discharged directly by many cultured organisms and generated as a by-product by many bacteria. Nitrite is somewhat less toxic than ammonia, although nitrite toxicity may occur in concentration of less than 2.5 ppm for some species. Nitrate is considered relatively non-toxic to most aquatic organisms.
Biological filtration is defined as the bacteriological conversion of organic nitrogenous compounds into nitrate. The several steps in this process are collectively referred to as the nitrogen cycle. Although the nitrogen cycle begins with conversion of nitrogen containing organic compounds into ammonia, this step usually is best completed before the material reaches the biological filter. Some ammonification and de-amination occur in all biological filters unless the filter influent is from a pure inorganic source. The primary purpose of a biological filter is conversion of ammonia to nitrite and nitrite to nitrate. This conversion is of great importance in culture of aquatic organisms because ammonia is a highly toxic metabolic waste discharged directly by many cultured organisms and generated as a by-product by many bacteria. Nitrite is somewhat less toxic than ammonia, although nitrite toxicity may occur in concentration of less than 2.5 ppm for some species. Nitrate is considered relatively non-toxic to most aquatic organisms.
Last modified: Thursday, 28 April 2011, 6:12 AM