B.O.D. concentration "B.O.D. concentration" is the intensity of the biochemical oxygen demand of effluent, measured by reference to the B.O.D. of a standard unit of volume of the effluent, such as a litre; thus effluent is said to have a B.O.D. concentration of, say, 5,000 milligrammes per litre, or 5,000 mg/1, if, its oxygen-consuming potential is such that one litre of it will, according to laboratory test, utilize, during a period of three days and at a temperature of 30 degrees Centigrade, 5,000 milligrammes of oxygen in the process of its biochemical oxidation; PU(A)342/1977 - ENVIRONMENTAL QUALITY (PRESCRIBED PREMISES) (CRUDE PALM-OIL) REGULATIONS, 1977 2. Interpretation.