Abstract: To address leachate accumulation caused by the increasing landfill volumes, a domestic waste sanitary landfill in Liaoning province expanded and upgraded its leachate treatment facilities, adding a treatment capacity of 600 m3/d. The leachate treatment adopted a process of “equalization + membrane bioreactor (MBR) + nanofiltration + reverse osmosis”. Nanofiltration concentrate was treated using a “volume reduction + coagulation-sedimentation” process, while reverse osmosis concentrate was treated by the process of “low-temperature evaporation+drying”, thereby achieving full-volume treatment. The design effluent standard complies with the class 1A limits specified in GB 18918—2002 Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant. Operational results showed that the system performed stably, with effluent COD content<20 mg/L, NH3-N content≤5 mg/L, and TN content≤10 mg/L, consistently meeting and outperforming the discharge limits. By adopting low-energy-consumption blowers and taking advantages of the low-temperature evaporation (LTE) process, the project effectively controlled operating costs, with a unit treatment cost of approximately 125 yuan/m3. This project provides a mature technical model for the efficient and cost-effective treatment of leachate at aging landfills, achieving a synergistic improvement in both treatment efficiency and economic performance.

Key words: leachate treatment, low-temperature evaporation, full-size treatment, low-carbon and high-efficiency