Treatment of leachate concentrate by electrocoagulation coupled with electro-Fenton-like process: Efficacy and mechanism

The efficient treatment of leachate concentrate is a key issue in the application of membrane technology to leachate treatment. Here a process coupling electrocoagulation with an electro-Fenton-like process was developed and tested for the treatment of leachate concentrate using a dual-anode system. The effects of pH, electrode gap, electrical charge, and suspended solids on the performance of organics and ammonia removal were evaluated with leachate concentrates from a municipal waste incineration facility. 57% of the organics and 60% of the ammonia were removed at the electrical charge of 7Ah/L, the potential of 7 V, and pH of 7. Electro-oxidation by hypochlorite ions generated in situ, electrocoagulation and electro-Fenton-like reaction via hypochlorite and ferrous ions achieved the removal. Higher levels of suspended solids and a smaller electrode gap both benefitted the removal of organics. Most of the fulvic acid and humic acid-like substances in the concentrate were removed, with the treatment effectiveness following the order coupled process > electro-Fenton-like process > electrocoagulation process. This coupled process shows an alternative potential as a preliminary process in the treatment of leachate concentrates.