Which test is commonly used to measure the concentration of dissolved oxygen in wastewater?

The measurement of dissolved oxygen (DO) in wastewater is crucial as it provides insights into the health of a body of water and the efficiency of the wastewater treatment process. The DO test specifically quantifies the amount of oxygen available in the water, which is essential for aerobic bacteria to decompose organic matter in wastewater. A higher concentration of dissolved oxygen indicates a healthier aquatic environment and is usually a positive sign in wastewater treatment.

The other tests serve different purposes: the Biochemical Oxygen Demand (BOD) test measures the amount of oxygen required by microorganisms to decompose organic material in water over a specific period, typically five days. While it relates to oxygen consumption, it doesn't directly measure the available dissolved oxygen. The Chemical Oxygen Demand (COD) test measures the total oxygen required to chemically oxidize organic and inorganic matter, but like BOD, it does not measure dissolved oxygen levels themselves. The pH test assesses the acidity or alkalinity of a liquid, which is also unrelated to dissolved oxygen levels.

Thus, the DO test is the appropriate choice as it directly measures the concentration of dissolved oxygen in wastewater, providing critical information for treatment processes and environmental assessments.