Chemical Oxygen Demand (COD) is a vital measure in water treatment, gauging the amount of oxygen needed to oxidize soluble and particulate organic material in water. This test is crucial in both drinking and wastewater systems to evaluate the water’s quality and the effectiveness of treatment processes.

In drinking water, COD levels indicate the presence of organic compounds, potentially signifying contamination. High COD values can suggest the presence of pollutants that may affect the water’s taste, odour, and safety. Regular monitoring is essential to ensure the water meets health standards and is safe for consumption.

In wastewater, COD is a key parameter to measure the effectiveness of treatment processes. It helps in assessing the organic load and determining the necessary treatment steps. High COD levels in wastewater can indicate insufficient treatment, leading to potential environmental harm when discharged.

• Laboratory Analysis: The most common method for COD testing involves adding a strong oxidising chemical to a water sample and measuring the change in a given time. This method provides accurate and quantifiable results but requires laboratory conditions and skilled personnel.
• Portable Testing Kits: For on-site testing, portable COD kits are available, offering quick and approximate results. These are particularly useful for routine monitoring and field analysis.
• Spectrophotometric Methods: Advanced methods use spectrophotometry to measure the absorbance of the oxidised sample, giving precise readings of COD levels.

Accurate COD testing is crucial, but it can be challenging due to the interference from other substances in the water. It’s essential to ensure that testing procedures are robust and that samples are representative of the water being assessed.

Regular and accurate determination of COD levels is integral to maintaining water quality standards in both drinking and wastewater systems. Through effective monitoring and treatment based on COD readings, water treatment facilities can ensure the safety and environmental compliance of their water systems.