The waste leachate generated from the operation of waste transfer stations poses a significant environmental pollution risk due to its complex and fluctuating water quality, which contains suspended solids, oil and grease, organic matter, salts, nitrogen, and other pollutants. To address this issue, an experimental study was conducted at a waste transfer station in Zhejiang Province, using a coagulation sedimentation, air flotation, ABR, and AA/O-MBR process. This multi-step treatment approach demonstrated remarkable effectiveness in treating the leachate. The coagulation sedimentation and air flotation unit successfully removed suspended solids and oil and grease from the leachate, while the ABR-AA/O biological treatment unit proved efficient in removing organic matter, ammonium nitrogen, and total nitrogen from the leachate. The experiment results showed that the influent water had initial concentrations of CODCr, NH+4-N, TN, and SS ranging from 15130 to 20540 mg/L, 278.0 to 413.0 mg/L, 289.0 to 437.0 mg/L, and 4330 to 6317 mg/L, respectively. After treatment, the effluent water exhibited significantly reduced concentrations, with CODCr, NH+4-N, TN, and SS ranging from 134 to 313 mg/L, 0.4 to 0.9 mg/L, 46.4 to 65.1 mg/L, and 8 to 14 mg/L, respectively. The average removal rates were 98.72% for CODCr, 99.81% for NH+4-N, 84.91% for TN, and 99.79% for SS. The effluent quality satisfied the requirements of the Water Quality Standards for Sewage Discharge into Urban Sewers (GB/T 31962—2015). In conclusion, the process has good technical adaptability and promising prospects for industrialization.