Which method is often used to determine BOD levels in wastewater?

The determination of BOD, or biochemical oxygen demand, is inherently linked to the specific test designed to measure the amount of oxygen that microorganisms will consume while decomposing organic matter in a sample of water over a specified period, typically five days at 20°C. The biochemical oxygen demand test accurately captures this process and provides a quantifiable measure of organic pollution.

This method monitors how much oxygen is consumed by microorganisms in the sample, revealing the level of biodegradable organic material present. The BOD test typically involves incubating the wastewater sample in a controlled environment and measuring oxygen levels before and after the incubation period, providing a clear indication of the BOD value.

In contrast, colorimetric analysis and gravimetric analysis focus on measuring concentrations of specific substances or solids in a sample but do not directly measure biological activity or oxygen consumption related to biodegradation, which is the core aspect of BOD. Respirometry, while related to measuring respiratory activity, does not specifically quantify biochemical oxygen demand as effectively as the designated BOD test. Therefore, the biochemical oxygen demand test is the most appropriate method for assessing BOD levels in wastewater.