Assessment Methods And Case Studies On Contaminated Sites Green And Sustainable Remediation

Green and Sustainable Remediation(GSR)of contaminated sites is an important part of sustainable management of soil environment.The study aims at the problems of lacking of sustainable risk management system of contaminated sites,imperfect decision-making mechanism of land safety utilization planning,and obvious secondary pollution of environmental remediation in China.Based on the evaluation and analysis of present situation of contaminated sites management and the remediation industrial development in China,this study adopted the approaches such as questionnaire survey,simulation evaluation and empirical analysis,using the methods of cost-benefit analysis(CBA)and life cycle assessment(LCA)etc.,to construct a set of GSR evaluation method for contaminated sites from both the regional level and site level.(1)Aiming at the asymmetry of information between regional redevelopment planning and contaminated sites remediation and pollution control in China,the regional sites remediation priority ranking and redevelopment planning evaluation method is established,and case studies are carried out.The results show that in the early planning stage,the net benefits of remediation and redevelopment can be significantly improved by adopting a step-by-step remediation and redevelopment policy that combines feasible measures for pollution remediation with land use types,compared with the traditional one-time remediation and policy-driven remediation scheme.(2)The LCA method is used to quantify and refine the secondary environmental impact assessment of the contaminated site remediation construction in the whole process,which can provide reference in the evaluate procedure and method parameter optimization for the use of LCA method in the GSR management of contaminated site in China.The study selected typical chromium contaminated sites in western region of China to carry out the overall LCA.The results show that among the secondary environmental impacts generated by the remediation construction,the personal health damage accounted for 45.63% of the total impact,the ecosystem damage accounted for 7.28%,climate change and resource consumption accounted for 24.13% and22.96% respectively.(3)The construction of CBA procedure method and evaluation index system forsite remediation project promotes the comprehensive evaluation of social,environmental and economic benefits in the whole process of contaminated sites remediation and a CBA model for contaminated sites remediation,which integrates health risks,ecological risks,resource and environmental impacts and external environmental impacts,is proposed.A case study of typical chromium-contaminated sites is carried out.The results show that the total cost of site remediation is about 105 million yuan.The comprehensive social,environmental and economic benefit obtained from remediation is about 240 million yuan within 100 years,and the net benefit of remediation is 135 million yuan.(4)In order to evaluate the increases of ecological benefits of GSR compared to the traditional site remediation mode,and the total social loss caused by the secondary pollution during the period of remediation,the study attempts to include the impacts for future land ecological service value of the contaminated site and surrounding land by remediation activities,an integrated assessment framework system and methodological basis incorporating Natural Resource Damage Assessment(NRDA)and GSR of contaminated sites were explored.A case analysis of remediation of soil and groundwater in a coking contaminated site was conducted.The pollution damage assessment based on GSR show that the direct ecological environment damage is close to 2.8 billion yuan,the actual cost of rehabilitation is 1.8 billion yuan,and the value loss of follow-up land ecological services after remediation is about 110 million yuan.In view of the social investment in site rehabilitation,besides the explicit actual repair expenditure,the society also bears the difference between the environmental damage caused by site pollution and the cost of rehabilitation,and the loss of land service value caused by the secondary environmental impact of remediation construction.