Abstract: Taking the stockpiled waste excavation project of a domestic waste sanitary landfill in South China as the analysis object, according to the hydrogeology of the landfill, the anti-seepage system and the physicochemical characteristics of the stockpiled waste, a modular and automated oxygen injection stabilization pretreatment system was designed in a phased, zoned, and layer-by-layer manner. This could enable the waste excavation unit to form an aerobic bioreactor and increase the conversion speed from anaerobic state to aerobic state. The stabilization goal could be achieved within a short period (less than 35 days), which is convenient for the subsequent excavation and transportation of stockpiled waste. Through the monitoring and control means of oxygen injection stabilization pretreatment, the concentration of methane gas in the waste pile was less than 3%, the odor concentration limit in the natural exhaust of the excavation unit met the requirements of GB 14554—1993 Emission Standards for Odor Pollutants, and the leachate head in a single-layer waste pile was less than 40 cm. At the same time, a large amount of degradable substances in the stockpiled waste were degraded, and the BDM index had a large drop compared with that before oxygen injection stabilization pretreatment.

Key words: domestic waste sanitary landfill, stockpiled waste, oxygen injection stabilization pretreatment, stabilization unit, waste excavation