Performance of coupling electrocoagulation and biofiltration processes for the treatment of leachate from the largest landfill in Hanoi, Vietnam: Impact of operating conditions

Landfill leachate remediation is quite challenging because of the presence of various different organic, inorganic compounds, microorganism materials, and heavy metals. Especially in case of a mature leachate, if only a single biological treatment system is applied, it will not be effective due to the high percentage of heat-resistant compounds, including mostly humic substances. Therefore, combining processes are necessary to effectively remove these substances to enhance the effectiveness of leachate remediation and to meet the water quality standards. In this research, a hybrid electrocoagulation-biofiltration system was applied to investigate the treatment of Nam Son landfill leachate, the largest landfill in the North of Vietnam. The results revealed the electrocoagulation (EC) process using iron anode could eliminate about 70% COD and 90% nitrate when applying the optimal conditions: current density of 3 A/m(2), at initial pH = 8, with a treatment time of 60 min, and an inter-electrode distance of 7 cm. The subsequent biofiltration (BF) process was capable of removing almost completely ammonia and remained COD from EC-pretreated leachate. The optimal parameters of aeration/pause mode and loading rate determined for BF process were 60:60 min and 5 L/d, respectively. These results demonstrated that an EC-BF hybrid process can be considered a model process for the removal of both organic and inorganic pollutants from landfill leachate.

Automated summary

Landfill leachate remediation is challenging due to the presence of various organic, inorganic compounds, microorganism materials, and heavy metals. This study demonstrated that a hybrid electrocoagulation-biofiltration system can effectively remove both organic and inorganic pollutants from landfill leachate, enhancing treatment efficiency.