废物处理方式对工业系统可持续性影响的能值分析

Emergy Evaluation of Impacts of Waste Treatment Methods on the Sustainability of the Industrial System

废物的不同处理方式对工业系统的可持续性影响不一样。在考虑了工业系统内废物处理、循环、系统间废物交换和污染物的排放对环境和经济影响的基础上,提出了能反映工业系统特点的能值分析方法和相应的指标体系,即能值节省率(PES)、产品转换率(PT)、能值产出率(EYR)、环境负荷率(ELR)、能值可持续指数(ESI)。以攀枝花某硫酸生产企业和某钛白粉生产企业为案例进行了分析。废物交换前硫酸生产企业的PES、PT、EYR、ELR和ESI分别为9.57%、8.52×108sej/g、3.29、5.56和0.59,钛白粉生产企业这五个指标分别为3.59%、10.40×108sej/g、2.56、26.19和0.10;废物交换后硫酸生产企业的这五个指标分别为23.96%、7.22×108sej/g、3.83、5.49和0.70,钛白粉生产企业这五个指标分别为13.25%、7.72×108sej/g、2.62、17.62和0.15。结果表明,这两个工业系统间的废物交换可提高它们的可持续性。最后针对它们目前存在的问题提出了相应的建议。

Exhaustion of some natural resources,such as raw mineral materials and fossil energy,has been imposing increasing restrictions on economic development;meanwhile,massive discharge of pollutants has also been making our environmental quality degraded.As such,enhancing resources efficiency and treating wastes play a fundamental role in promoting social and economic sustainable development.However,waste treatment methods have important impacts on resources efficiency of the industrial systems,which can finally affect the sustainability of industrial systems.This paper considers those environmental and economic impacts from waste treatment and recycling in industrial systems,waste exchanges among industrial systems,and waste discharge.The authors then put forward an improved emergy index system for evaluating the sustainability of industrial systems,including Percent of eMergy Saving（PES）,Product Transformity（PT）,eMergy Yield Ratio（EYR）,Environmental Loading Ratio（ELR）,and eMergy Sustainability Index（ESI）.A sulfuric acid enterprise and a titanium dioxide powder enterprise in Panzhihua City,Sichuan Province,were analyzed through examining such indicators.Values of PES,PT,EYR,ELR and ESI for the sulfuric acid enterprise were found to be 9.57%,8.52×108 sej/g,3.29,5.56 and 0.59,respectively,and values of the five indicators for the titanium dioxide powder enterprise were 3.59%,10.40×108 sej/g,2.56,26.19 and 0.10,respectively,before waste exchanges.Values of the five indicators for the sulfuric acid enterprise were 23.96%,7.22×108 sej/g,3.83,5.49 and 0.70,respectively,and values for the five indicators for the titanium dioxide powder enterprise were 13.25%,7.72×108 sej/g,2.62,17.62 and 0.15,respectively,after waste exchanges.Results showed that waste recycling in the two industrial systems and waste exchanges between them can enhance their resources efficiency,mitigate environmental pressures,and strengthen their sustainability because waste exchanges reduce inputs of fresh resources.This saves production costs and cuts emissions.Therefore,waste exchanges tend to lead to a mutually beneficial relationship between the two enterprises.However,waste exchanges between them were very limited for their sustainability improvement due primarily to a very small portion of wastes being reused and their great dependence on non-renewable resources.Consequently,the two enterprises need to innovate continuously in technologies and create more opportunities for waste exchanges.Meanwhile,it was indicated that the titanium dioxide powder enterprise benefits more than does the sulfuric acid enterprise from waste exchanges,so the titanium dioxide powder enterprise may compensate the sulfuric acid enterprise through some way in order to maintain this type of mutually beneficial relationship for a long time.This study can provide helpful reference for improving the comprehensive performance of industrial parks.