Municipal Solid Waste Anaerobic Bioreactor Landfill Technology Pilot Study

Applying the technology on anaerobic bioreactor landfill to municipal solid waste disposal of the science city in MianYang SiChuan, the study was carried out on three different lab-scale reactors (No.1, No.2, No.3), with the same volume of 5 m³, No.1 simulating a currently conventional landfill, where solid waste was used, while No.2 and No.3 simulating a anaerobic landfill, where horizontal trenches of leachate recirculation methods were used in the lab-scale reactors No.2 and vertical wells of leachate recirculation methods were used in the lab-scale reactors No.3.The results of the study are as follows: firstly, leachate produced from the anaerobic bioreactor landfill could be effectually minified and put down within landfill when it was reintroduced into the landfilled solid waste; secondly, the observed pH levels of the semi-aerobic bioreactor landfill were on the acidic side of the pH scale after week 10, while that of the conventional landfill after week 26; thirdly, there were more landfill gas output in the lab-scale reactors No.2 and No.3 than No.1.The methane appeared at seventh week in the lab-scale reactors No.2 and the concentration was about 21.4%, The methane appeared at sixth week in the lab-scale reactors No.3 and the concentration was about 19.2%, The methane appeared at sixteenth week in the lab-scale reactors No.1 and the concentration was about 6.2%; fourthly, the BOD/COD ratio of the leachate from the anaerobic landfill ranged from 0.30～0.53, showing good biodegradability, while that of the leachate from the conventional landfill fluctuated from 0.34 to 0.19, its biodegradability went from good to bad; fifthly, during the end of the study, subsidence rate of the waste was 9.17% in landfill NO.1, 24% in NO.2, and 20% in NO.3, subsidence rate of the volatile 11.69% in NO.1, 30% in NO.2, and 23.81% in NO.3.The results of the study proved that anaerobic bioreactor landfill have great advantages over the currently conventional landfills in that anaerobic bioreactor could operate to enhance the total output of land fill gas, to accelerate the reduction of COD, BOD, NH₃-N, TP and heavy metals, to accelerate the biological decomposition of organic waste, to accomplish the stabilization of the landfill through the recirculation of leachate meanwhile to achieve the reduction of leachate discharge.On the basis of the characterization of the anaerobic bioreactor landfill, the author proposed in this paper that firstly, by leachate recirculating, leachate be cleaned in site. Sceondly the horizontal trenches of leachate recirculation will be of great benefit to moisture diffusion in the waste relative to vertical wells of leachate recirculation.