How to determine the COD testing standards for high-salt wastewater
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It is well known that COD testing yields inaccurate results under high-salt (high chloride) conditions, and there is a discrepancy between such data and the actual values. Therefore, I would like to ask everyone how accurate COD measurement can be achieved in situations with high salt concentrations?
My suggestion: When the chloride level is high enough, it’s not very meaningful to test for COD. You can use TOC testing to determine the degree of organic pollution in the water; the specific procedures will require you to purchase the necessary instruments first. The chlorine correction method has significant limitations, and its parallelism is also poor
Additional note: The testing method we use is the potassium dichromate method as specified by national standards; although there is a chlorine correction factor, the results remain inaccurate. We also have TOC detectors, but TOC can only measure total organic carbon, while COD measures reducible substances; there is a difference between the two. Moreover, the organic content in our wastewater is not high. And the reductant content is very high. Therefore, TOC cannot simply be used to replace COD, and the environmental protection agency also does not approve of this. This post was last edited by lyhh9024 on 2009-2-9 13:13]