地下式污水处理厂全生命周期综合效益评价

Life Cycle Comprehensive Efficiency Assessment on Underground Wastewater Treatment Plant

地下式污水处理厂建设近年在我国兴起,且有扩展之势。地下污水厂地表可形成的景观环境直观、易觉,这就使污水处理厂可与景观环境建设合二为一的说法盛行。反观更加缺地的欧洲、日本等地,地下式污水处理厂其实并不多见,让人不免心生疑窦。因此,有必要通过一些方法对地下式污水处理厂进行综合影响评价,以揭示其综合效益之优劣。以国内某全地下式污水处理厂为研究实例,并以相同工艺的地上式污水处理厂作为对比参照物,通过全生命周期环境影响评价(LCIA)、全生命周期成本(LCC)评价及全生命周期生态效益(LCEE)评价3种方法分别对地下式污水处理厂进行全方位影响评价,最后将3种评价结果归一化为全生命周期综合影响(LCCI)评价。综合影响评价结果显示,地下式污水处理厂在环境影响、基建投资、生态效益三方面的综合负面影响较地上式要高出约20%。虽然地下式污水处理厂地表园林景观会产生一定生态效益,但这并不能“中和”其环境影响以及基建投资所产生的负面效益。因此,地下式污水处理厂建设并非优选方式,需要因地制宜,选址要特别慎重。

Constructing underground wastewater treatment plants(UWWTPs)prevails recently and tends to extend largely in China.Ecological landscape saved by UWWTPs is easy to be seen,which makes an opinion popular that wastewater treatment could combined with ecological landscape.In Europe and Japan much shorter of land,however,it is rare to see UWWTPs,which makes us a query.Therefore,it is necessary to comprehensively assess UWWTPs in some ways and to reveal their pluses and minuses.Based on life cycle impact assessment(LCIA),life cycle cost(LCC)assessment and life cycle ecological efficiency(LCEE)assessment,the study assessed omnibearingly the impacts and efficiencies of UWWTPs,and finally the assessed results from each assessment were normalized into life cycle comprehensive impact(LCCI)assessment.The assessment was based on a real domestic UWWTP,and a proposed surface WWTP was used as a counterpart for comparison.The LCCI results revealed that the comprehensively negative efficiency of UWWTP on the environment,infrastructure investment and ecological efficiency was about 20%higher than that of its counterpart.Although the ecological landscape restored by the UWWTP could form a certain ecological efficiency,it could not neutralize the negative efficiency of the UWWTP on the environment and the infrastructure investment.As a result,UWWTPs are not a preference approach to municipal wastewater treatment.So constructing UWWTP should act according to circumstances and selecting sites of UWWTP have to be prudent.