What is COD?

2024.06.03
Erun Environmental Protection

In the field of environmental protection and water quality monitoring, COD is a very important parameter, which means chemical oxygen demand in Chinese. COD is one of the important indicators to measure the degree of water pollution. It represents the total amount of organic and inorganic matter that can be oxidized in water. So, what exactly does COD mean?

COD refers to the content of organic matter and some inorganic matter in water that can be oxidized by strong oxidants such as dichromate. These organic matter in water consumes dissolved oxygen in water through biodegradation or chemical oxidation reactions, resulting in a decrease in the content of dissolved oxygen in water, thus affecting the survival and reproduction of aquatic organisms. Therefore, the higher the COD value, the more pollutants there are in the water and the worse the water quality. COD measurement is usually used to evaluate the degree of pollution of industrial wastewater, domestic sewage and natural water bodies.

Therefore, the COD content in water means that the water contains a large amount of organic matter, which may come from human activities, such as industrial wastewater, agricultural drainage and domestic sewage. These organic substances need to consume a lot of oxygen when decomposing in the natural environment, resulting in a decrease in the dissolved oxygen content in the water, thus affecting the survival of aquatic organisms. When the dissolved oxygen content is too low, aquatic organisms may die due to lack of oxygen, resulting in the destruction of the aquatic ecosystem, and may also be transmitted through the food chain, posing a potential threat to human health.

COD is usually measured using the potassium dichromate method (CODcr) or the potassium permanganate method (CODMn). The potassium dichromate method used by the erun-c1 series COD water quality detection analyzer produced by Yingrun Environmental Protection is the most commonly used COD measurement method. Its principle is to use potassium dichromate as an oxidant under acidic conditions to oxidize the reducing substances in the water sample into carbon dioxide and water, and then calculate the COD value based on the amount of oxidant consumed. The erun-c2 series also uses the potassium permanganate method, which uses potassium permanganate as an oxidant for determination under alkaline conditions. If you need detailed information and water quality testing equipment prices, you can directly consult the website customer service or call the website contact number.

In order to control the discharge of COD, many countries and regions have formulated corresponding emission standards. the COD emission limits of different industries are different, but overall they are constantly tightening to reduce pollution to the environment. Therefore, controlling the discharge of COD is of great significance to protecting water resources and the ecological environment. By formulating and implementing strict emission standards and adopting effective sewage treatment technology, we can effectively reduce the discharge of COD, strengthen the monitoring and control of water quality indicators such as COD, and ensure the quality of water bodies and the stability of the ecosystem.

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