Study On The Coordinated Operation Of The Anaerobic-Semiaerobic Bioreactor Landfill

Sanitary landfill is the main mode on the dispoal of municipal solid waste nowadays and in the future for a long time in our country, however, the traditional landfill will be faced with the secondary pollution if the process of design, construction and operation management is not based on the standard; and also have other disadvantages, such as the higher concentrations of pollutants, slower steady rate, longer post-regulatory period, larger environmental risks. Therefore, the traditional landfill is difficult to meet the requirement of environmental protection under the new situation. The appearance of bioreactor landfill technology indicates a new direction, but each type of bioreactor landfill has its own advantages and disadvantages. For the sake of combining the advantages of different types of bioreactor landfill, this paper assembled anaerobic bioreactor landfill and semiaerobic bioreactor landfill in space to devise an anaerobic-semiaerobic bioreactor landfill technology which would be applied to the dispoal of rural solid waste, in order to broaden the way on the dispoal of rural solid waste.Based on the laboratory experiments, this paper discussed the running effects of the anaerobic-semiaerobic bioreactor landfill under different conditions, and then determined the optimum operation condition in the acidification phase. According to the results of experiments, this paper focused on the coordinated operation strategy of the anaerobic-semiaerobic bioreactor landfill. The results showed that:Compared to the anaerobic bioreactor landfill and the semiaerobic bioreactor landfill, the anaerobic-semiaerobic bioreactor landfill which applied the cross recirculation could relieve acid accumulation effectively, but also had a better contaminant removal effect. After145d operation, compared to the1anaerobic bioreactor landfill and the2#semiaerobic bioreactor landfill, all anaerobic-semiaerobic bioreactor landfill had advantages on the remove rates of chemical oxygen (COD) and ammonia nitrogen (NH3-N), of which5#anaerobic-semiaerobic bioreactor landfill reached the highest COD removate rate to79.13%, and3#anaerobic-semiaerobic bioreactor landfill reached the highest NH3-N removate rate to49.95%. The trends of biologically degradable material (BDM) and settlement were more obvious than the comparing model. Compared to the1#, other anaerobic model released less gas. All results indicated that the anaerobic-semiaerobic bioreactor landfill is more conducive to the removal of pollutants and garbage degradation in the acidification phase, thus speeding up the process of stabilization of solid waste.By selecting four indicators, such as leachate recirculation frequency, the proportion of cross recirculation, pH and aeration time, this paper designed a orthogonal experiment which had four factors and three levels. The remove rates of COD and NH3-N were selected as the evaluation standard. Finally this paper came to a conclusion that A3B1C3D1is the optimum operation condition of the anaerobic-semiaerobic bioreactor landfill in the acidification phase. Namely, recirculation frequency was3d/time, the proportion of cross recirculation was50%(each unit of anaerobic-semiaerobic bioreactor landfill recharged leachate to itself by50%, another50%was recharged to the unit in series with it), leachate pH was adjusted to8.0, and aeration time was20min. In this condition it would get the best operation results.In the process of designing the anaerobic-semiaerobic bioreactor landfill, the anaerobic unit and the semiaerobic unit could be arranged in a mixed way, and also in a separate way. The ability of seepage control and leachate and gas collection and discharge needed to be strengthened. In the actual operation process, different control method should be used to get better operation results in different phases based on different unit arrangements. By taking reasonable partitioning design, the anaerobic-semiaerobic bioreactor landfill site reuse could be realized and service time would be longer, which meeted the target of sustainable development.