Chemical Oxygen Requirement (CoA °) determination

Chemical Oxygen Demand (COD) Determination
Chemical Oxygen Demand (COD) Determination

One of the most important criteria applied to determine the degree of pollution of industrial or domestic wastewaters is the need for chemical oxygen. Chemical oxygen demand (COD) refers to the amount of oxygen required for oxidation of oxidizable substances, particularly in industrial wastewaters. The biological oxygen demand (BOD) is based on the oxidation of organic matter by biochemical reactions, while the chemical oxygen demand is based on the oxidation of these substances by redox reactions. This means that one or more electrons pass from one atom or molecule to another. During this reaction, in the oxidation environment, carbonaceous organic substances are converted to carbon dioxide and water, and nitrogenous organic substances are converted to ammonia. If there is no electron transfer, the need for chemical oxygen cannot be excluded. The most important consideration of the determination of the chemical oxygen demand is the termination of the reactions in a very short time. The determination of biological oxygen demand is completed in 5 day, while the determination of chemical oxygen demand is completed within 3 hours.

The determination of the chemical oxygen demand in wastewater, unlike the determination of biological oxygen demand, includes a number of biological substances which do not decompose by biological means. Therefore, the value of chemical oxygen demand (COD) is always greater than the value of biological oxygen demand (NON).

The need for chemical oxygen (COD) is also an important indicator in the studies of the pollution of rivers in industrial wastewater. If there are no toxic substances in the water, only organic matter that can be easily decomposed, the resulting KO value is approximately equal to the BOD value.

Chemical oxygen demand (COD) analyzes are often used to measure the concentration of organic matter in domestic and industrial residues containing toxic substances for biological life. is a method.

In authorized laboratories, between chemical analyzes chemical oxygen demand (COD) determination studies are carried out. The standard taken into account in these studies is:

 

  • TS 2789 Water quality - Determination of chemical oxygen demand