Removal of Chromium, Nickel, Zinc and Turbidity from Industrial Wastewater by Electrocoagulation Technology (Case Study: Electroplating and Galvanized Wastewater of Industrial Zone in Boomhen)

Background and Heavy metals such as chromium, nickel, and zinc are the most common contaminants found in the plating wastewater that cause environmental pollution due to non-biodegradability. This study investigated the removal of chromium, nickel, zinc and turbidity from wastewater of plating and galvanized industries by electrocoagulation technology. This study was conducted at laboratory scale using four parallel aluminum electrodes (5cm × 10cm dimensions, 1 mm thickness). In each electrode, 6 holes (0.7 cm) were considered. Wastewater samples were first collected as grab sampling and finally changed to combined samples. This study was performed in pH= 3 and pH= 7.2 for plating wastewater and pH= 9 for galvanized wastewater and reaction times of 20, 40, 60 and 80 minutes. Nickel and chromium contents in plating wastewater were 45 and 50 mg/l, respectively. Zinc concentration in galvanized wastewater was determined 210 mg/l. Turbidity in plating and galvanized wastewaters were 250 and 200 NTU, respectively. The maximum removal of nickel and chromium was observed in contact time= 80 min and pH=4, while it was seen in pH=9 for zinc (98 %, 95.6%, and 94%, respectively). The maximum removal of turbidity in Ni – Cr wastewater and galvanized wastewater was 97% and 95.3%, respectively. Electrocoagulation technology was found as an effective, economical and rapid method for infiltration of toxic wastewater in plating and galvanized industries.