Evaluation of applying membrane distillation for landfill leachate treatment

Landfill leachate contains high concentrations of toxic and harmful substances. A combination of membrane separation and biological treatment process is commonly used for landfill leachate treatment, but the capital and operation costs are very high. To simplify the treatment process, membrane distillation was directly investigated in landfill leachate treatment to eliminate the adverse effects. The rejection performance was systematically studied, and both membrane fouling and membrane wetting were investigated. Besides, the feasibility of MD treatment driven with the on-site waste heat was evaluated. The results show that the landfill leachate could be efficiently purified by MD with excellent rejections of TOC (>98.93%), phosphate (>99.19%), and metal irons (>99.95%) in all tested conditions, and the membrane was not wetted during the whole experimental duration (8 h). Ammonia nitrogen could not be fully rejected at the neutral pH condition (46.4%), but feed acidification (pH 5.0) could increase the rejection rate to 94.24%. Feed acidification also enhanced membrane fouling resistance with a final specific flux of 0.74 after concentrating the landfill leachate by 5 times. Energy consumption analysis showed that the waste heat in an incineration power plant was sufficient to drive the on-site treatment by MD in the form of AGMD. This work may provide a green option for landfill leachate treatment.