کارآیی حذف کروم، نیکل، روی و کدورت از فاضلاب صنایع آبکاری به روش الکتروکوآگولاسیون

Background and purpose: 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. Material and methods: 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. Results: 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. Conclusion: Electrocoagulation technology was found as an effective, economical and rapid method for infiltration of toxic wastewater in plating and galvanized industries.