BOD

         COD is a non-specific test that measures the quantity of both bio-degradable and non-biodegradable organic matter and is reported as "ppm as oxygen". The test measures the ability of a hot chromic acid solution to oxidize organic matter. [....]

           BOD is a non-specific test that measures the quantity of "biologically-degradable" organic matter and is reported as "ppm as oxygen". The test measures the quantity of oxygen depletion resulting from the ability of common bacteria to digest organic matter during a 5-day incubation period at 20 Deg C. [....]