An Instrument for Determination of Energy Oxygen and BOD5

"The biochemical oxygen demand (BOD) determination is an empirical test in which standardized laboratory procedures are used to determine the relative oxygen requirement of waste waters, effluents and polluted waters [1]." This method has several well-known drawbacks, i.e., 5-day duration of the test, lack of correspondence of the BOD bottle to the biological system of the receiving water body, and the nonquantitative nature of the BOD test [2]. Each of these factors seriously compromises the present testing procedure. The length of the analysis time, which is generally 5 days, makes the test practically useless [2,3] in real-time control of pollution, and the prescribed condition of carrying out the test at a constant temperature of 20 'C is an inconvenience. The objective of this investigation was to develop an instrument which would measure biological oxygen demand by some parameter which was meaningfully related to the oxygen depleting activity of waste waters, precise, and of short measurement duration (I hour or less). The variable chosen was energy oxygen, a thermodynamic value related to the substrate free energy of oxidation in cell synthesis [2-8]. Two factors, energy oxygen and endogenous oxygen, comprise ultimate biochemical oxygen demand [2,3,4]. Five-day BOD (BOD5 ), may not necessarily exert the ultimate biochemical oxygen demand because 5 days may be too short a time for complete stabilization by the bacteria. Thus we can summarize