Design of Leachate Drainage System in Shallow Landfill Areas

Abstract

Leachate drainage systems in landfills often face issues like pipe blockage and reduced seepage flow over time. Inadequate leachate drainage can lead to rising leachate levels in the waste heap, negatively impacting landfill gas collection efficiency. This study aimed to develop and test an air-lift device to improve leachate drainage in shallow landfills. The air-lift device was designed to lift leachate while allowing simultaneous landfill gas collection under negative pressure. Experiments examined how air pressure, submergence depth, pipe diameters, and lifting height affected the leachate outlet flow rate of the device. Orthogonal experimental analysis found submergence depth and lifting height had the most significant influence on outlet flow rate. A multiple regression model was developed to quantify the effects of these parameters. Additionally, a foam separator was incorporated into the device design and removed 20 -30% of non-settleable particles from the leachate. While the foam separator improved leachate water quality, its effect on air quality requires further study. Overall, the air-lift device successfully lifted leachate and collected landfill gas simultaneously, providing an efficient alternative drainage method for shallow landfills.