Which parameter is essential for evaluating the biological treatment efficiency?

Biochemical Oxygen Demand (BOD) is a crucial parameter in assessing the efficiency of biological treatment processes in wastewater treatment. It measures the amount of oxygen that microorganisms will consume while decomposing organic matter in the water. A higher BOD indicates a greater amount of organic material present, meaning that the biological treatment process must be more effective to break down these substances.

Monitoring BOD helps operators determine how well the biological treatment system is functioning; a significant decrease in BOD after treatment suggests that the microorganisms are effectively digesting the organic pollutants. This efficiency can indicate the system's capability to remove contaminants and produce effluent that meets regulatory standards. Ensuring that BOD levels are appropriately managed is vital for environmental protection and maintaining water quality in receiving bodies.

While pH, temperature, and chlorine are also important for overall treatment effectiveness, they do not directly measure the biological treatment's efficacy the way BOD does. pH affects microbial activity, temperature influences reaction rates, and chlorine is typically used for disinfection rather than evaluating biological treatment processes. Thus, focusing on BOD provides a clear view of the biological treatment's success.