Electrochemical Treatment of Industrial Wastewater Containing Phenols

The use of phenolic resins for manufacturing different textile products in a company, our case example, generates wastewater with high phenol concentration (30-400 ppm) and chemical oxygen demand (COD) between 3,000 and 15,000 ppm. Moreover, the effluent also contains high chloride concentrations ranging between 4000 and 7000 ppm, ions with a concentration of ca. 2000 ppm, and suspended solids. A study at the laboratory scale of the anodic electrochemical treatment of this industrial effluent has been carried out. The influence of variables such as current density, pH, and charge passed on phenol degradation and COD reduction was studied. As anodes, or or Pt/Ti were used. As the separator, a 117 Nafion cation exchange membrane was employed. The results showed that the final COD value was lower than 1000 ppm. After electrochemical treatment the final concentration of phenol was lower than 1 ppm, and the COD decrease was 70-80%. Unidentified aliphatic carboxylic acids and alcohols were the main products of oxidation. For electrolyses carried out at alkaline pH, the only halocompound detected in the anolyte, gas, and aqueous phases, was chloroform regardless the electric charge passed, the current density employed, and the anode used. © 2002 The Electrochemical Society. All rights reserved.