Which method is typically used to measure Biochemical Oxygen Demand (BOD)?

The method typically used to measure Biochemical Oxygen Demand (BOD) is through chemical analysis over a specified incubation period. BOD is an important parameter in wastewater treatment that indicates the amount of oxygen that microorganisms will consume while decomposing organic matter in a sample of water.

To accurately measure BOD, a sample of wastewater is collected and then placed in a controlled environment, typically at a set temperature (usually 20 degrees Celsius), for a specific incubation period, commonly five days. During this time, the microorganisms in the wastewater will break down the organic matter, consuming oxygen in the process. The change in oxygen levels before and after the incubation period is then measured to calculate the BOD value.

This method is especially reliable because it reflects the actual biochemical processes occurring in the wastewater and provides a clear indicator of the organic pollution present.

The other methods mentioned—such as instantaneous monitoring, visual inspection, and temperature readings—are not suitable for measuring BOD because they do not effectively quantify the oxygen demand associated with biological activity. Instantaneous monitoring does not account for bacterial action over time, visual inspection provides no quantitative data, and temperature readings primarily measure physical conditions rather than biochemical processes.