典型厨余垃圾处置利用技术的环境与[火用]生命周期评价

Environmental and exergetic life cycle assessment of typical kitchen waste treatment and utilization technologies

垃圾分类收集后产生的大量厨余垃圾需资源化处理。采用合适的方法进行评估,以选择更环保节能的厨余垃圾处置利用技术尤为重要。典型的厨余垃圾处置利用技术包含以下4类:焚烧发电、厌氧发酵(发酵产生的沼渣可分为焚烧、堆肥或填埋3种处置方式)、好氧堆肥(包括阳光房堆肥及机器成肥)及填埋。通过现场调研采样和实地数据分析,采用环境生命周期评价(LCA)和[火用]生命周期评价(ELCA)的方法对4类技术的环境负荷及能量转化进行定量评估。其中,LCA以标准化环境负荷为指标,环境影响程度与其值呈正相关,4类技术的结果从低到高分别为好氧堆肥、厌氧发酵、焚烧发电及填埋。ELCA以积累[火用]消耗效率为评价指标,能量转化效率与其值呈正相关,4类技术的结果从高到低分别为好氧堆肥、厌氧发酵、焚烧发电及填埋。2种好氧堆肥方式中,阳光房堆肥的环境负荷更低(-0.366),而机器成肥的积累[火用]消耗效率更高(83.53%);3种厌氧发酵沼渣的处置方式中,沼渣堆肥的环境影响(-0.189)和积累[火用]消耗效率(35.25%)均表现最佳。填埋在所有技术中环境负荷最高(1.231)且积累?消耗效率最低(9.76%)。本研究结果可为厨余垃圾资源化利用方法的选择提供参考。

With the implementation of the source-separated municipal solid waste collection in China,an increasing amount of kitchen waste is collected and transported separately.Therefore,the treatment and utilization of kitchen waste have become one of the greatest challenges we face.Under such circumstances,thorough investigations to assess an environmentally friendly and energy-efficient treatment and utilization technology of kitchen waste are of great significance.Environmental life cycle assessment(LCA) and exergetic life cycle assessment(ELCA) methods were used to quantitatively assess environmental burden and energy conversion efficiency of four typical kitchen waste treatment and utilization technologies,namely,incineration,anaerobic fermentation(the digestate treatment methods after anaerobic fermentation including incineration,composting or landfill),aerobic composting(including aerobic composting under sunlight and mechanical aerobic composting) and landfill.Data in this research used for the comparison was mainly based on field investigation and sampling.The standardized environmental burden was an indicator of LCA,which was positively correlated with the degree of environmental impact.The results of the four technologies were aerobic composting,anaerobic fermentation,incineration and landfill,from low to high.ELCA was assessed by cumulative exergy consumption efficiency and the energy conversion efficiency is positively correlated with its value.The results of the four technologies from high to low were aerobic composting,anaerobic fermentation,incineration and landfill.Regarding aerobic composting,the sunlight case had a lower environmental impact(-0.366),whereas the cumulative exergy consumption efficiency of mechanical aerobic composting was higher(83.53%).In terms of the digestate treatment methods after anaerobic fermentation,the composting of digestates was the most recommended option,with the best environmental impact(-0.189) and cumulative exergy consumption efficiency(35.25%).The landfill had the highest environmental burden(1.231) and the lowest cumulative exergy consumption efficiency(9.76%) among all technologies.The results obtained from this research could serve as a theoretical basis for the development and application of clean and efficient technology for kitchen waste treatment and utilization.