What does Chemical Oxygen Demand (COD) measure in wastewater?

Chemical Oxygen Demand (COD) measures the amount of oxygen consumed by pollutants in water, specifically organic and inorganic substances. It quantifies the total quantity of oxygen that is required to oxidize both biodegradable and non-biodegradable matter present in a sample of wastewater. This measurement is crucial as it provides an estimate of the degree of pollution, indicating how much of the organic matter in the water can deplete oxygen in receiving water bodies, which can be harmful to aquatic life.

COD is often used as a reliable indicator for wastewater treatment efficiency because it encompasses a broad spectrum of organic compounds, thus giving a more inclusive picture of water quality compared to other methods, such as Biological Oxygen Demand (BOD), which focuses only on biodegradable materials. Therefore, the measurement of the oxygen demand is essential for assessing the impact of wastewater discharges on the environment and helps in designing effective wastewater treatment processes.