Treatment of paint manufacturing wastewater by electrocoagulation

Treatability of paint manufacturing wastewater (PMW) by electrocoagulation (EC) process was investigated. Effects of operating parameters for the EC process such as electrode type (Al or Fe), initial pH (2–10), current density (5–80 A/m 2) and operating time (0–50 min) were evaluated for optimum operating conditions. The highest removal efficiencies for COD and TOC in PMW were obtained with 93% and 88% for Fe and 94% and 89% for Al electrodes at the optimum conditions (35 A/m 2, 15 min and pH 6.95). Operating costs for removal of PMW at the optimum conditions were calculated for Fe and Al electrodes as 0.187 €/m 3 and 0.129 €/m 3. Toxicity test was carried out to obtain information about toxic effect of the raw and treated wastewaters at optimum operating conditions. The samples measured by respirometric method contained hardly toxicities. Performance of Al electrode was better than that of Fe electrode in terms of removal efficiency and operating cost. ► Electrocoagulation process is a fast and effective method for the treatment of PMW. ► EC process has provided high COD removal efficiency (94% for Al electrodes). ► Operating costs were 0.187 and 0.129 €/m 3 for Fe and Al electrodes, respectively. ► Toxicity of raw and treated wastewaters was hardly seen.