What does the presence of high BOD in wastewater indicate?

The presence of high Biochemical Oxygen Demand (BOD) in wastewater is a critical indicator of water quality, particularly reflecting the level of organic pollution. BOD measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. When BOD levels are high, it suggests that there is a significant amount of organic material — such as plant debris, food waste, and waste from humans and animals — present in the water. This organic pollution can lead to depleted oxygen levels in the water body, which can harm aquatic life and disrupt ecosystems. High BOD is thus a direct indication of the biological load that bacteria and other microorganisms need to process, making it a key parameter in assessing water quality and the efficiency of wastewater treatment processes.