基于生命周期评价的多氯联苯污染场地修复技术的筛选

我国的多氯联苯(PCBs)污染场地数量多、分布广,现有的两家固定式高温焚烧厂已经难以满足实际工程的要求,迫切需要引入移动式处理技术和设施,以推进我国污染场地环境无害化管理的进程.针对设施开发和引进过程中面临的技术选择问题,本文选择国际上已经商业化成功运行的碱性催化分解(BCD)和红外高温焚烧(IRI)技术作为移动式非焚烧和焚烧技术的代表,应用生命周期评价(LCA)结合影响评价2002+方法(IMPACT2002+),分析比较了两种技术在处理PCBs污染土壤全过程的环境影响.研究结果表明,处理1000kgPCBs污染土壤,BCD和IRI技术的综合环境影响分别为0.147和0.279Pt.论文还分别对两种技术的预处理、主处理、废气处理、废水处理及废渣处理等工艺单元的中间环境影响和最终环境影响进行了逐项分析和比较,鉴别了两种技术在处理PCBs污染土壤时各单元过程负面环境影响的主要来源,为两种技术的工艺优化提供了一定的基础数据和理论依据.

Application of life cycle assessment(LCA) to remediation technologies selection for PCBs contaminated sites

There are numerous polychlorinated biphenyls(PCBs) contaminated sites throughout China,and the two existing fixed high temperature incineration plants struggle to meet the remediation needs for these sites.For environmentally sound management of the contaminated sites,mobile remediation technologies and equipment are required.In this research,life cycle assessment was carried out to study the environmental impacts of two mobile remediation technologies in application at a PCBs contaminated site.The chosen technologies were base catalyzed decomposition(BCD) and infrared high temperature incineration(IHTI),which are mobile non-incineration and incineration technologies,respectively.A combined midpoint/damage approach was adopted using SimaPro 7.2 and IMPACTA2002+ to assess the human toxicity,ecotoxicity,climate change impact,and resource consumption from five IHTI and BCD subsystems.Based on treatment of 1000 kg of PCBs contaminated soil,our preliminarily conclusion is that the environmental impact of BCD is less than that of IHTI.The total single score of BCD was 0.147 Pt while that of IHTI was 0.279 Pt.The major environmental impacts through the whole lifecycle arose from the treatment process,off-gas treatment,and wastewater treatment in both BCD and IHTI.These results could be used to optimize treatment technologies.