WEF Discussion Forums
Laboratory Management and Technical Issues
Comparison of manometric and disolve oxygen method of BOD
I asked Standard Methods why there was this difference in the depletion targets for the two methods. They forwarded my Query to experts within AWWA and this is their response, "In 5210B, oxygen depletes to near stasis conditions for aerobic organisms; in the respirometric test, oxygen is not limited, because air is renewed periodically keeping oxygen levels in a higher range throughout the test. I don't know of any lab that ever gets consistent GGA results above 220 with 5210B." This answer is quite logical. It does contradict my experience. We used Oxtitops in the past to avoid week-end work. Our GGA results were higher than the dilution method by a few mg/L but no where near 260 mg/L.