Not quite correct. BOD5 is the amount of oxygen consumed by bacteria over exactly a 5-day incubation period at 20 deg C in the dark. It represents both carbonaceous and nitrogenous (due to ammonia present) oxygen demand. CBOD5 is the "Carbonaceous" component of BOD5. Letting the test run for 20-days results in a greater oxygen demand and is referred to as Ultimate BOD; however, depending on the biodegradability of the organic matter present, aerobic biological decomposition may continue past 20 days. It is an estimate of the amount of biodegradable organic matter and is used to determine the oxygen supply requirements for aerobic treatment, as well as the oxygen sag due to treated effluent discharged into a receiving water body.
Published by Troy Vassos, Senior Environmental Engineer
Not quite correct. BOD5 is the amount of oxygen consumed by bacteria over exactly a 5-day incubation period at 20 deg C in the dark. It represents both carbonaceous and nitrogenous (due to ammonia present) oxygen demand. CBOD5 is the "Carbonaceous" component of BOD5. Letting the test run for 20-days results in a greater oxygen demand and is referred to as Ultimate BOD; however, depending on the biodegradability of the organic matter present, aerobic biological decomposition may continue past 20 days. It is an estimate of the amount of biodegradable organic matter and is used to determine the oxygen supply requirements for aerobic treatment, as well as the oxygen sag due to treated effluent discharged into a receiving water body.