Influence Of Landfill Structure On Leachate Characteristics

Sanitary landfllling remains one of the most principal methods of municipal solid waste disposal at the present time. But, nowadays landilling technique just takes landfill as a passive storage waste place, the wastes in landfill were isolated with outside water and air. Moisture content in landfill was so low that it couldn't provide microorganism with feasible condition, organic compounds in wastes biodegradation was restricted. Accompanied by differential settlement, landfill gas and leachate emissions, the dumped refuse will biodegrade slowly and gradually in the long process of landfill stabilization These emissions could last for decades or even centuries and result in a significant negative impact on the environment. So, every country has taking measures to ameliorate landfllling technique to accelerate landfill stabilization process and weaken leachate pollution.Disposal function is an important function of MSW landfllling. With the increasing of air and moisture content in landfill, compound organic material can be decomposed by microorganism quickly, so the stabilization process of landfill site is accelerated. At the same time, the compound organic material in leachate will be degraded by microorganism when leachate is in the recirculation, and the leachate quality is improved. Both change the landfill structure and bio-reactor landfllling are used disposal function of MSW landfill to improve leachate quality and landfill stabilization.Four large scale landfllling installations were built according to semi-aerobic landfllling and anaerobic landfllling theories. Two anaerobic landfllling installations used as contrast. The concentrations of COD, BOD5, NH₃^-N and NO₃^--N and pH were detected regularly. The results showed that, the concentrations of pollutants in leachate of semi-aerobic landfllling structure reduced more quickly than that in anaerobic landfilling structure, the concentrations of COD BOD₅ and NH3-N in leachate of semi-aerobic landfill treatment declined rapidly, and after 28 weeks keep about 300mg/L 50mg/ and 30mg/L and. The reduce rate reach 98.9%, 99.7% and 99.0% respectively and the value of BOD5/ COD also keep about 0.1 after 13 weeks. However the concentrations of COD BOD5 and NH3-N in leachate of anaerobic landfill treatment still keep about 1000mg/L 150mg/L. 1200mg/L and the value of BOD5/COD above 0.1 in whole stage. The concentration of NO₃^--N in leachate of semi-aerobic landfill structure in low state in prophase and it ascend quickly up to 300mg/L in anaphase But in anaerobic structure it can't be detect. The pollutant concentrations in leachate of semi-aerobic landfilling structure reduced regularly, but which in aerobic landfilling leachate varied greatly in early period of experiment. Based on the experiment data, the attenuation equations of pollutants in leachate of semi-aerobic landfill structure were acquired.In order to study on influence of landfill structure on leachate recirculation effect, Leachate was recirculated into one semi-aerobic landfill and one anaerobic landfill and the concentrations of COD and NH3-N were detected regularly last sixteen weeks. The results showed that, leachate...