Modelling and Multi-response Optimisation of Leachate Treatment by Electrocoagulation using Full Central Composite Design

Abstract

Electrocoagulation has lately received much interest as an effective method for the treatment of landfill leachate because of its ease of use, low cost, and environmental friendliness. The present study aimed to investigate the reduction of chemical organic demand (COD), biological organic demand (BOD5), and turbidity from leachate by electrocoagulation process using aluminium electrodes. In order to achieve the maximum removal of pollutants, highlight the key effects of the variables and their simultaneous relationships, full central composite design was applied. Moreover, the backward model selection method using Bayesian Information Criterion and Akaike Information Criterion was carried out to determine the most suitable model with relevant effects. The optimum conditions indicated by the estimated quadratic models were initial pH (5.04), current density (407 A m–2), reaction time (74.6 min), and stirring speed (150 rpm), adjusted R2 of 99.82 %, 99.93 %, and 99.95 % for COD, BOD5, and turbidity, respectively. Electrocoagulation was also successful in achieving 90 % COD, 92.3 % BOD5, and 99.6 % turbidity removal efficiency. The findings indicated a satisfactory agreement between model forecasts and experimental values.

Keywords

• wastewater
• electrocoagulation
• backward selection
• central composite design
• response surface methodology