What is the purpose of reducing BOD in wastewater treatment?

The purpose of reducing Biochemical Oxygen Demand (BOD) in wastewater treatment primarily focuses on protecting aquatic life. BOD is a measure of the amount of oxygen that microorganisms will consume while decomposing organic matter in water. High BOD levels indicate a significant amount of organic pollution, which can lead to depleted oxygen levels in water bodies. This depletion can create hostile environments for aquatic organisms, leading to stress or death of fish and other aquatic species. By reducing BOD through treatment processes, the amount of organic material in the water is decreased, allowing oxygen levels to remain adequate for sustaining healthy aquatic ecosystems.

While increasing nutrient levels, enhancing pH, or increasing sludge volume may be relevant in specific contexts, they do not address the fundamental environmental and ecological goal of wastewater treatment, which is to mitigate harmful effects on aquatic life resulting from untreated or poorly treated wastewater. Therefore, protecting aquatic life is the core objective in reducing BOD levels.