Which of the following compounds is typically measured during the wastewater treatment process?

Biochemical Oxygen Demand (BOD) is a critical measure in the wastewater treatment process, as it indicates the amount of organic matter present in the wastewater. BOD reflects the quantity of oxygen that microorganisms will consume while decomposing organic substances in water. This measurement is crucial for assessing the effectiveness of the treatment process and for ensuring that the treated effluent meets regulatory standards before being discharged into the environment. High BOD levels in the influent suggest a strong presence of biodegradable material, which can impact the efficiency of biological treatment processes. Monitoring BOD helps operators make informed adjustments to treatment strategies, thereby improving overall water quality.

While calcium, phosphorus, and nitrogen may also be significant in wastewater treatment—particularly in nutrient removal processes—they are not primary indicators of the overall organic load present in wastewater like BOD is.