The meaning of COD
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What is the purpose of taking samples from the heat exchanger’s circulating water to test COD? I hope to receive guidance from all the teachers. Thank you!
COD (Chemical Oxygen Demand) and its significance: It refers to the amount of oxygen consumed by certain chemical reagents in wastewater when they oxidize organic matter in the wastewater or reduce inorganic substances. It is a comprehensive indicator used to assess the degree of water pollution; the higher the COD level in wastewater, the more organic matter it contains. High COD generally facilitates the growth of microorganisms, leading to an increase in microbial proliferation, algae growth, or total P levels, which in turn accelerates scaling and is detrimental to the system. It’s just hard to say; it’s not that it’s impossible. If the COD value is too high, exceeding several hundred, then it’s not acceptable. Whether corrosion occurs depends mainly on acidity and chloride levels – high acidity or high chloride levels can cause corrosion in the system, while low acidity can lead to the formation of calcium and magnesium deposits.
Generally, high turbidity is caused by oil leaking from the heat exchanger; if hydrocarbons leak, it will lead to an increase in COD. Usually, oil in the water sample can be seen with the naked eye, but in the case of heat exchangers containing hydrocarbons or minor leaks, it is only possible to determine whether there is a leak by analyzing the changes in COD in the inlet and outlet circulating water samples.
Generally, high turbidity is caused by oil leaking from the heat exchanger; if hydrocarbons leak, it will lead to an increase in COD. Usually, oil in the water sample can be seen with the naked eye, but in the case of heat exchangers containing hydrocarbons or minor leaks, it is only possible to determine whether there is a leak by analyzing the changes in COD in the inlet and outlet circulating water samples.