The Performance of Electrocoagulation Process in Removing Organic and Nitrogenous Compounds from Landfill Leachate in a Three-Compartment Reactor

In this study, the effectiveness of the electrocoagulation (EC) process was evaluated based on the reduction of organic and nitrogenous contaminants in landfill leachate. A three-compartment electrochemical reactor as pre-treatment of stabilized landfill leachate was carried out ahead of biological treatment. The removal efficiencies of COD, BOD, ammonia, and nitrate were analyzed at pH 4, 6, and 8 with the current densities of 20.83 and 29.17 mA.cm(-2). At pH 4, the highest removal of COD and NH4+ was obtained, i.e.. in the range of 72-81% and 43-59%, respectively. The ratio of BOD5/COD was increased after EC, from initially 0.11 to 0.32 at pH 4. In addition, EC effectively removed humic substances in the leachate by targeting a large amount of high molecular weight humic substances. with around 10(3) kDa. However, the higher removal efficiency observed at higher current density leads to higher specific energy consumption. At a current density of 29.17 mA.cm(-2). the specific energy consumption obtained in EC was around 10-17 Wh.g(-1) COD and 99-148 Wh.g(-1) NH4+. This could be decreased up to 50% at an applied current density of 20.83 mA.cm(-2) with slightly lower efficiencies.

Automated summary

This study evaluated the effectiveness of electrocoagulation (EC) in reducing organic and nitrogenous contaminants in landfill leachate. The results showed that the highest removal of COD and NH4+ was achieved at pH 4. In addition, EC effectively removed humic substances in the leachate, but higher current densities led to higher energy consumption.