Electroplating for chromium removal from tannery wastewater

The performance of electroplating in the removal of chromium ions from crude tannery wastewater and from a synthetic wastewater solution was investigated. Brazil is a major producer of leather, and such industries generate large environmental impacts. A novel batch reactor setup was developed for tannery wastewater treatment, employing graphite and aluminum as anode and cathode, respectively. Crude wastewater from a tannery was characterized and presented an acidic pH, elevated biochemical oxygen demand and chemical oxygen demand, and a total chromium concentration of 544 mg/L, a value that is one thousand times higher than permitted by local legislation. Electroplating was able to remove 90.0% of chromium content from a synthetic trivalent chromium solution. Moreover, 96.5% of total chromium content was removed when electroplating was applied in untreated tannery wastewater. Additionally, antifoam addition inhibited foam generation during the electroplating process without interfering in chromium removal. The results showed that the electroplating technique is a viable wastewater treatment alternative and/or a complement for tannery industries that use chromium as a tanning agent.