Sulphate radical-based advanced oxidation technologies for removal of COD and ammonia from hazardous landfill leachate: A review

ABSTRACT

Solid waste landfill (SWL) is known as a major pollution source contaminating air, water sources, and soil environment. The main hazard of SWL is leachate including high organic matter and nutrients. Recently, sulphate radical-based advanced oxidation processes (SR-AOPs) based on persulphate (PS) have been applied as a useful method for removal of chemical oxygen demand (COD) and ammonia from landfill leachate (LL). The removal efficiency of the SR-AOPs depends on effective parameters such as pH, oxidant dosage, catalyst dosage, temperature, reaction time, and so forth. Among SR-AOPs, thermal persulphate oxidation (TPO) seems to be promising for removal of both COD and ammonia; however, the high amount of energy cost is regarded as a major drawback. The drawbacks and future challenges for the use of SR-AOPs for LL have been discussed, and some strategies such as using coupled mechanisms of SR-AOPs have been proposed to tackle the common difficulties. Finally, the performance of SR-AOPs for treatment of LL has been compared with hydroxyl radical processes.

KEYWORDS:

• Landfill leachate
• persulphate
• sulphate radicals
• COD reduction
• ammonia reduction

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).

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