Chemical oxygen demand of biochemically treated coke-plant wastewater

Abstract

The factors responsible for the high chemical oxygen demand (COD) of biochemically treated coke-plant wastewater are identified. The factors responsible for overestimation of the COD in bichromate tests are also determined. Experiments show that the interference of inorganic reducing agents formed in biochemical treatment must be eliminated in determining the COD. To reduce the consumption of the reagents used to improve the results of COD tests (including the need for toxic mercury sulfate), special methods of preparing the wastewater samples are recommended.