A Pilot-Scale Electrocoagulation-Artificial Wetland Hybrid System for the Treatment of Landfill Leachate

In the present study, the technical feasibility of an electrocoagulation-constructed wetland continuous flow treatment system for the removal of organic matter, such as chemical oxygen demand (COD), from landfill leachate was evaluated. The response surface methodology (MSR) was applied to assess the simple and combined effects of the independent parameter’s potential and distance between electrodes on the removal efficiency and optimization of the electrocoagulation process conditions. The constructed wetland system consisted of a horizontal subsurface flow system coupled to a vertical subsurface flow system using the macrophyte Canna indica. For a COD concentration without pretreatment around 5142.8 mg L-1, the removal percentage for the electrocoagulation system was 79.4% under the optimal working conditions (Potential: 20 V; Distance: 2.0 cm). The COD removal efficiency in the artificial wetland with Canna indica showed a dependence with the hydraulic retention time, reaching 59.2% for 15 days. The system overall efficiency of the system reached about 91.5% removal of the organic matter, expressed as COD. In addition, removal of parameters such as biochemical oxygen demand (BOD: 94.8%) and total suspended solids (TSS:88.2%) were obtained. This study demonstrated that the coupling of electrocoagulation coupled with a constructed wetland system is a good alternative for the treatment of organic contaminants in landfill leachate