Wastewater pollution source apportionment of electrolytic manganese industry based on the equivalent pollution load method

The wastewater with complicated compositions generated by the electrolytic manganese industry was from many processes, and the systematic quantitative data of the water pollution load in each process was relatively lacking. Through research on technical data that accounted for 85% of the industry’s total capacity, five source analysis processes including leaching oxidation, pressure filtration, electrolysis and subsequent sections, leachate from residue field and initial rainwater were determined, and four analytical factors including chemical oxygen demand, ammonia nitrogen, total chromium, and total manganese were also determined. The analysis results of pollution source apportionment provided important basic data and reference for formulating industrial environmental management policy standards, guiding the direction of technology research and development, and leading technology promotion and application.The equivalent pollution load source analysis results indicated that the equivalent pollution load of the wastewater from the production of one ton of manganese was 6 119.7. Total manganese, ammonia nitrogen and total chromium were the main pollutants, and the cumulative load ratio was 99.7%. The electrolysis and subsequent sections, leachate from residue field, and pressure filtration, with the equivalent pollution load ratio being 47.2%, 27.8% and 22.6%, respectively, were the key processes of the industrial environmental management. Meanwhile, it was discovered that the leachate from residue field had a higher pollution load, which needed urgent attention. The processes with the greatest water pollution load and emission reduction potential were electrolysis and subsequent sections, which were also the key processes of technology research and development, and the cleaner production technologies developed for these processes could significantly reduce the equivalent pollution load.