Electrocoagulation-Electro-Fenton hybrid system for dairy wastewater treatment: A comprehensive test and analysis, in aqueous solution

This study aimed to assess the efficacy of a treatment system combining electrocoagulation (EC) and Electro-Fenton (EF) for the remediation of the wastewater dairy industry. Synthetic samples simulating dairy effluent were prepared and subjected to characterization for turbidity, chemistry oxygen demand (COD), and pH. The Box-Behnken design, comprising operating parameters such as electric current (0.5 to 1.5 A), electrolysis time (5 to 17.5 min), initial pH (4.0 to 9.0), and hydrogen peroxide concentration (0 to 9.0 g/L), with three replications at the central point. The combined treatment was conducted in a batch reactor using iron electrodes and subsequently filtered using a qualitative filter paper. Analysis revealed the significance of electric current, electrolysis time, and peroxide concentration at a 5 % probability level for COD reduction. A reduction of 80 % in chemical oxygen demand (COD) and a 99 % reduction in turbidity were achieved by maintaining the original pH of the wastewater and using a combination of an electric current greater than 1 A and an electrolysis time of 11.5 min, without the addition of hydrogen peroxide. The results showed that the treatment followed the standards of the Brazilian legislation.