Development of a novel electrocoagulation anode for real urban wastewater treatment: Experimental and modeling study to optimize operative conditions

Abstract

Electrocoagulation (EC) is one of the most cost-effective techniques for eliminating pollutants from wastewater. The objective of the present work was to develop a novel low-cost EC anode-based aluminum scrap shape by valorizing used aluminum cans, in attempts to increase the contact rate between the pollutant molecules and EC anode leading to enhance the pollutants removal efficiency from urban wastewater. Moreover, to optimize the EC operative conditions with reducing the number of required experiments, modeling by Box-Behnken design (BBD) in response surface methodology was performed to investigate the effects of many operating parameters: initial pH, applied current, operating time and packed density, on the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), phosphorous (P) and fecal coliforms (FC). Considering the treatment energy consumption, the results led to two important operative conditions for cost-effective EC treatment: economic and optimal conditions for experimental and modeled removals. The predicted results from BBD modeling regarding economic operative conditions were found to be COD (Y1) 80%, BOD (Y2) 84%, P (Y3) 96%, and FC (Y4) 99%, with an energy consumption (Y5) of 3.50 kWh m−3. Accordingly, experimentally validation using economic operative conditions resulted in removal efficiencies of COD (78.5%), BOD (83%), P (94.7%), and FC (99%) with a lower energy consumption of 2.52 kWh m−3. Hence, the predicted results revealed a good agreement with the experimental data. These findings could pave the way to reduce significantly the number of required experiments for other research works, and make aluminum based-electrode as a promising candidate for development and scale-up a low-cost EC electrode.