Environmental Impacts Of Disposing Wasted Clay Brick Based On The Life-cycle Assessment

For quantitatively evaluating environmental impacts of disposing constructionsolid wastes, this article, based on the theory of Life-Cycle Assessment (LCA) andBuilding Environmental Performance Analysis System(BEPAS), builds the frameworkand process of environmental impacts assessment by creating the index ’’netenvironmental benefit (NEB)’’ and ’’environmental benefit-cost ratio (NBCR)’’,which takes the environmental cost of disposal process and the environmental benefit ofrenewable materials into consideration.Taking the disposition of wasted clay brick as case, this paper summs up itsdisposal pattern as three categories with reusing, recycling and landfill. The disposalpattern of recycling includes five utilization channels of using the broken brickaggregate for concrete aggregate or concrete block raw material, as well as taking thebrick powder as burned brick raw material, unburned masonry cement raw material orcement mixture. The environmental costs of disposal process and alternative material ofevery disposal pattern have been calculated, according to the hypothesis that theenvironmental impact effect of the same quality alternative material and renewablematerial is consistent, we conver the calculated environmental cost of alternativematerial for the environmental benefit of renewable material, and then get the value ofnet environmental benefit and environmental benefit-cost ratio. The result indicates：From the index "net environmental benefit", the value of landfill is lower thanreusing, and the cost of recycling is relatively higher. Among the several ways ofrecycling, the descending order of net environmental cost is cement mixture, concreteblock material, unburned masonry cement raw material, concrete aggregate and burnedbrick raw material. The net environmental benefit of burned brick raw material isnegative, which means the environmental benefit can’t offset environmental cost. Onlyfrom the perspective of environmental impact assessment, both landfill and burnedbrick raw material are not applicative.From the index "environmental benefit-cost ratio", the value of reusing, unburnedmasonry cement raw material, cement mixture and concrete block material are all morethan1.But the value of burned brick raw material and landfill are less than1, which means they are not applicative.Resulting from the applicatition of disposal pattern, the two indexes of netenvironmental benefit and environmental benefit-cost ratio have the same conclusion.Further from the order of environment performance of these disposal ways, we find thetwo results are not entirely consistent that the best way is unburned masonry cementraw materials and reusing separately.Further studies show that, whether or not taking the environmental impactevaluation of renewable material，the conclusions are very different. In fact, to assessthe environmental impacts of disposing construction solid wastes, the environmentalbenefit of renewable material can not be ignored, otherwise the results would be lack ofreliability.