Abstract: A MSW landfill in Guangdong province had reached the limit of storage capacity, and had environmental pollution and safety risks, which need to be rectified. The comprehensive remediation of the project phased closure was implemented by taking engineering measures such as landfill shaping, mid-term covering, leachate collection and drainage, rainwater interception and drainage, groundwater vertical barrier,contaminated groundwater pumping and groundwater (surface water) pollution monitoring. After the remediation of the project, groundwater and the settlement rate of landfill pile were regularly detected, which could availably prevent environmental safety risks after the phased closure of the landfill and minimize secondary pollution. Meanwhile, the average leachate treatment capacity of the landfill decreased from 966 t/d in 2019 to 380 t/d in 2023, and the leachate production gradually stabilized. The settlement rate of landfill pile gradually decreased from 2.41 mm/d (87.97 cm/a) in April 2021 to 0.76 mm/d (27.74 cm/a) in September 2023, and the settlement rate gradually slowed down after a rapid decline. According to GB/T 25179—2010 Technical Requirements for Site Utilization after Stabilization in Municipal Solid Waste Landfill, the project is still in the uneven settlement period (10~30 cm/a) at this stage, and continuous dynamic monitoring is required. The main pollution indicators of groundwater including CODMn and NH3-N concentration basically met the requirements of the Class IV standard limit in the GB/T 14848—2017 Standard for Groundwater Quality. The implementation of engineering measures for this project could provide powerful data support for the safe utilization of the landfill site after the phased closure, while it also could provide reference for similar projects in the future.

Key words: MSW landfill, comprehensive remediation, phased closure project, waste stability