Pan Jilang, Voulvoulis Nickolaos
Centre for Environmental Policy, Imperial College London, London, United Kingdom.
J Air Waste Manag Assoc. 2007 Feb;57(2):155-63. doi: 10.1080/10473289.2007.10465317.
In Europe, the European Union Landfill Directive aims to reduce the negative environmental impacts of landfilling. This is mainly to be achieved by reducing the quantity of organic matter deposited, through measures such as the separate collection and recycling of the organic waste stream or pretreatment of residual wastes before landfilling. Other than incineration or other thermal processes, mechanical biological treatment is playing an increasingly important role. This study was conducted to seek the benefits of municipal solid waste (MSW) pretreatment, as well as the differences in methane production from the landfilling of untreated and mechanically/biologically treated (MBT) MSW using GasSim simulation. Results demonstrated that methane production rates vary significantly among waste fractions. Those that contribute most to methane generation (organic material and potentially reusable or recyclable material) could be targeted and treated before landfilling. The statistic relationship from the first phase of the study indicated that to match the increasingly stringent landfill waste organic content allowance, local councils should prioritize the reduction/sorting of certain targeted fractions, such as paper, card, green waste, and other putrescibles from MSW. Moreover, mechanical treatment alone produces organic-rich waste called mechanically sorted organic residues (MSORs), which can be viewed as an organic content concentration process. Mechanically and biologically pretreated waste, on the other hand, differs significantly from untreated MSW and MSORs. This work demonstrated that if efficient mechanical-biological treatment is used, considerable reductions in biological activity, landfill gas production, and energy content/total organic carbon could be achieved. Using GasSim, reductions in methane production of >74% have been simulated if a 90% organic content reduction can be achieved during biological treatment on MSORs. A 50-60% organic content reduction by following biological treatment can turn MSOR properties only into normal MSW equivalent though considerably less volume.
在欧洲，欧盟的《填埋指令》旨在减少填埋对环境的负面影响。这主要通过减少有机物质的填埋量来实现，具体措施包括对有机废物流进行单独收集和回收，或者在填埋前对残余废物进行预处理。除了焚烧或其他热工艺外，机械生物处理正发挥着越来越重要的作用。本研究旨在探寻城市固体废物（MSW）预处理的益处，以及利用GasSim模拟比较未经处理的MSW和经过机械/生物处理（MBT）的MSW填埋过程中甲烷产生量的差异。结果表明，不同废物组分的甲烷产生率差异显著。那些对甲烷生成贡献最大的组分（有机物质以及潜在可再利用或可回收的物质）可以在填埋前进行针对性处理。研究第一阶段的统计关系表明，为了符合日益严格的填埋废物有机含量标准，地方议会应优先减少/分类某些目标组分，例如来自MSW的纸张、卡片、绿色废物和其他易腐物质。此外，仅机械处理就能产生富含有机物的废物，称为机械分选有机残渣（MSORs），这可被视为一种有机含量浓缩过程。另一方面，经过机械和生物预处理的废物与未经处理的MSW和MSORs有显著差异。这项工作表明，如果采用高效的机械生物处理，生物活性、填埋气产量以及能量含量/总有机碳都能大幅降低。利用GasSim模拟，如果在对MSORs进行生物处理期间能实现90%的有机含量降低，甲烷产量可减少74%以上。通过后续生物处理将有机含量降低50 - 60%，虽然体积会大幅减小，但MSOR的性质仅会变为相当于普通MSW的性质。
