Technical Perspective of Landfill Leachate Treatment via Membrane Distillation Using Waste Heat from Biogas...

In this study, we investigated the potential of using the combustion of biogas generated in landfills for power generation as an alternative waste heat resource for landfill leachate treatment. The effectiveness of direct-contact membrane distillation (DCMD) for wastewater treatment was also evaluated. The performance of DCMD was assessed based on conductivity, chemical oxygen demand (COD), and ammonia retention by testing both synthetic and raw landfill leachate. Results showed that the permeate stream had low COD (<0.5 mg/L) and turbidity (<1 NTU); however, ammoniacal nitrogen exceeded the maximum discharge limits defined by Brazilian legislation, indicating the need for additional treatment. Energy consumption analysis through simulations demonstrated that partial feed recycling in DCMD improved energy efficiency, achieving a gain output ratio (GOR) of 2.54 and reducing specific energy consumption (SEC) by 25%. The simulations showed that landfills producing more than 6.4 m³/h landfill leachate can meet treatment demands with on-site energy, while smaller facilities may require supplemental energy. Full allocation of biogas energy enables complete water recovery at all sites, demonstrating the feasibility of DCMD in landfill operations.