Influence of experimental parameters in the treatment of tannery wastewater by electrocoagulation

Electrocoagulation (EC) was carried out using a laboratory-scale system for the treatment of tannery wastewater (TWW). Statistical experimental design was applied to investigate the effect of various operating parameters (OP) including initial pH, electrode material (EM), and effluent load (EL). Analysis of variance showed that the proposed models fitted well with the removal of COD and TSS; high coefficient of determination values were obtained (R-2 > 0.99). The results show that the EL was an important factor affecting pollutant removal from TWW. COD and TSS removals are principally controlled by EL and initial pH. However, EM has no significant effect on TSS removal and its effect on COD removal is contracted at neutral pH medium. The treatment of TWW with an EL = Eff.am (COD0: 5634 mg l(-1), TSS0: 910 mg l(-1), and Cr-0: 75 mg l(-1)) at neutral pH allows removal of more than 64%, 96%, and 99% of COD, TSS, and chromium, respectively, as well as a significant color reduction. Working at 68 mA and after 15 min of electrolysis process time, under optimal OP, the EC reactor operational cost is 2.01 US$ m(-3). EC technique coupled to an equalization basin could be recommended as an effective process on TWW treatment.