Simultaneous removal of chromium and organic pollutants in tannery wastewater by electroprecipitation technique

The simultaneous removal of chromium and other organic pollutants from tannery wastewater was investigated in a batch electrochemical membrane reactor. This reactor, having a total capacity of 1 liter, was separated into two compartments (anodic and cathodic compartments) by using an anionic membrane. A stainless steel sheet with the square holes having total surface area of 0.0215 m² and a Ti/RuO₂ grid was used as the cathode and anode, respectively. The results indicated that the optimum condition for removal of chromium from tannery wastewater was found at the current density of 60.5 A/m² at initial pH of 4.5. At this condition, more than 98% of chromium was removed within 60 min. Some organic pollutants contained in wastewater such as oil and grease, color and the level of biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total kjeldahl nitrogen (TKN) were also markedly reduced.