An instrument has been developed that measures the amount of oxygen consumption of a wastewater sample in the presence of excess microbial population and dissolved oxygen. In a closed circulatory system the sample experiences rapid microbiological oxidation with a measurement of oxygen consumed (designated EO, energy oxygen) by a DO electrode.
The ABODA instrument (automatic BOD analyzer) measures EO of wastewater samples in less than one hour. EO shows an excellent correlation to BOD5 with correlation coefficients, r, of 0.997 and 0.99 for glucose-glutamate standard, and raw sewage and primary effluent samples, respectively. The reproduceability for the analyses are as follows: EO, 209 analyses with a weighted average cv of ± 5.1 % and BOD5, 200 analyses with a weighted average cv of ±9.8%. The instrumental determination of EO is not temperature dependent as the BOD5 test. Considering these factors the instrumental determination of EO allows the rapid measurement of BOD5.