Comparison Study of Different BOD Tests in the Determination of BOD7 Evaluated in a Model Domestic Sewage

The aim of this research was to study the suitability of a manometric respirometric test (OECD 301F) for the determination of biological oxygen demand (BOD) in domestic wastewater. This was done by comparing four different BOD tests (a manometric respirometric test, oxygen sensor determination, iodometric titration, and UV absorption measurement) and by evaluating the BOD(7) value after a short-term measurement applying the manometric respirometric test. Measurements were done in three different laboratories. The respirometric test was performed well on municipal sewage, and the precision of results was good. There were minor deviations between BOD(7) values as determined by the different methods, but the deviations were not essentially big enough to have a practical impact. Evaluation of the BOD(7) value after two or three days' incubation by the respirometric method was shown to work well; average deviations between measured and evaluated values after three days' incubation were 5-18%. Hence, the manometric respirometric test proved to be a rapid and suitable tool for process control purposes.