This method describes the determination of the chemical oxygen demand in wastewater photometrically with a cuvette test.
Wastewater generated in the industrial production of beer and food
The chemical oxygen demand (COD) is determined through a reaction with strong oxidizing agents, in which the consumption of an oxidizing titrant solution serves as a measure of the content of oxidizable impurities present in the sample. Almost all water-soluble substances and many undissolved organic substances are oxidized in the reaction. A volumetric standard solution of potassium dichromate is mixed with a strong sulfuric acid solution; silver sulfate is utilized as a catalyst, and mercury(II) sulfate serves as a masking agent for chlorides.
Oxidizable substances in the water sample react with the sulfuric acid potassium dichromate solution in the presence of silver sulfate as a catalyst. Chloride is masked with mercury sulfate. The decrease in the yellow color of Cr6+ is measured.