Laboratory Simulation Study On Leacheate From Semi-Aerobic Landfill

In view of the existing defects in anaerobic landfills, especially the difficulty of their leachate treatment, laboratory simulation and mathematics modal of semi-aerobic landfills are introduced to investigate the leachate quality, factors influencing it and its degradation rules. The simulative results show that the leachate's COD of semi-aerobic landfills decrease to National Discharge Standard Class I (100mg/L) in 2-3 years, and ammoniac nitrogen reduce to the standard (15 mg/L) in one year or so. In contrast, the leachate's COD and ammoniac nitrogen of anaerobic landfill need more than one decade and even several decades to decrease to the same standard. Therefore, the author reaches the conclusion that the self-purity ability of semi-aerobic landfills is very powerful. This finding provides an important idea and effective method for the treatment and control of leachate from landfills.Laboratory simulation is carried out to find out how different densities of refuse and diameters of leachate collection pipes influence the leachate quality of semi-aerobic landfills. The results show that (1) the density of refuse is one of the important factors to influence the leachate quality degradation. The less the refuse density is, the better the leachate quality degradation is. Whereas, the predicted results of ammoniac nitrogen degradations in case of different refuse densities display that once the refuse density is less than 535 kg/m3, the refuse density has little effect on the leachate ammoniac nitrogen degradation. (2) the diameters of leacheate collection pipes is also one of important factors to influence the leachate quality degradation. The longer the diameter of leachate collection pipe is, the better the leachate quality degradation is. However, the predicted results of COD degradations in case of different diameters of leachate collection pipes reveal that once the diameter of leachate collection pipes is more than 50mm, the influence of the leachate collection pipes' diameter on the leachate COD degradation is not obvious at all. The above research findings offer valuable references to the further study and engineering application of semi-aerobic landfills.