Potassium dichromate method (CODCr) is often used in environmental monitoring to analyze COD in water samples. The waste solution produced by using a large number of H2SO4, Ag2SO4, HgSO4 and K2Cr2O7 is a strong acidic multi-metal pollution waste liquid, which contains refractory organics, toxic heavy metals such as Ag+, Hg2+, Cr3+ and Cr6+, and the concentration of waste sulfuric acid is as high as 30%, A comprehensive treatment method was used to remove the toxic heavy metals from the waste liquid, thus the content of heavy metals in the wastewater reaches the standard.
