This dataset represents the treatment process of leachate generated from landfill activities. The dataset is applicable to the humid Zone I (long-term average annual precipitation of 800--1600 mm), with treatment technologies primarily including filtration separation, centrifugal separation, sedimentation separation, neutralization, chemical precipitation, chemical coagulation, anaerobic hydrolysis, anaerobic biofilters, stabilization ponds, constructed wetlands, and land treatment methods.