COD (Chemical Oxygen Demand) is a term used to measure the quality of water. It is a measure of water pollution resulting from organic matter. This parameter is defined as the amount of oxygen (in milligrams per liter of sample) required for the oxidation of all organic matter contained in a water sample. COD limits are set by competent authorities for various effluents permissible for accepting them in Effluent treatment plants or for releasing them to the environment. Among the various methods and instruments available, a non-dispersive absorption based instrument has been found to be the best for this. The Uniphos COD Analyzer is based on the above principle.