What does the biochemical oxygen demand (BOD) measure in water?

The biochemical oxygen demand (BOD) measures the amount of oxygen required by microorganisms to decompose organic matter present in water. This assessment is crucial for evaluating the organic pollution level within a water sample. When organic materials are present, microorganisms consume oxygen while breaking down these materials, which in turn impacts the dissolved oxygen levels in the water.

By quantifying BOD, one can infer the potential impact of wastewater on the receiving water bodies, as high BOD levels indicate that there is a significant amount of biodegradable organic content that could lead to depletion of dissolved oxygen if released into the environment. Consequently, this can affect aquatic life and overall water quality.

BOD is an essential parameter in wastewater treatment processes because it helps operators understand the achievable treatment levels needed to protect aquatic life and ensure safe water discharge. The other options measure different aspects of water quality, such as solids or harmful chemicals, but do not specifically indicate microbial activity or the oxygen demand associated with organic decomposition.