| Unsymmetrical dimethylhydrazine(UDMH)is one type of highperformance liquid rocket fuels,which generates wastewater during transportation,storage,and cleaning processes.UDMH wastewater usually has significant adverse impacts on human health and the ecological environment,so it has to be treated carefully.Currently,most research on UDMH wastewater focuses on treatment technology and analytical detection,and there is no study on the environmental impacts on the treatment processes.Based on the life cycle assessment(LCA)theory,this study used the Simapro 9.0 software and the CML-IA midpoint assessment method to quantify the environmental impacts and economic benefits of four advanced oxidation technologies(Fenton,UV-Fenton,electrochemical oxidation with ruthenium-iridium titanium electrode as anode and electrochemical oxidation with BDD electrode as anode)for treating UDMH wastewater.The analytic hierarchy processed(AHP)-fuzzy comprehensive evaluation method was employed to comprehensively rank the four technologies,in order to identify the best treatment process.LCA results indicate that,for most environmental impact categories under the same functional unit,the environmental burden size of the four advanced oxidation technologies in decreasing order is: UV-Fenton <Fenton < electrochemical oxidation with BDD as anode < electrochemical oxidation with ruthenium-iridium titanium as anode.All four technologies are beneficial to reducing eutrophication.External cost accounting related to environmental benefits was conducted based on traditional internal cost accounting.The results show that UV-Fenton(10.51 CNY/m3)is the most economical method,while electrochemical oxidation with BDD electrode as anode has the highest cost(180.10 CNY/m3).Sensitivity analysis shows that the decrease of chemical reagents and electricity consumption can significantly reduce environmental and economic impacts,and changing the current coal-fired power generation mode to hydropower,wind power,or nuclear power can reduce environmental burden.Based on the comprehensive environmental impact results,it is recommended to vigorously developing hydropower.Combining environmental and economic analysis results,an AHPfuzzy comprehensive evaluation method was used to construct a comprehensive evaluation index system for the treatment of UDMH wastewater by advanced oxidation technologies.1 goal layer,3 criterion layers,12 indicator layers,and 4 scheme layers were set.A comprehensive evaluation of the four advanced oxidation technologies was conducted based on the questionnaire survey results of 11 experts and scholars.The results show that UV-Fenton has the highest comprehensive score of the treatment of UDMH wastewater,indicating that it has a significant advantage when considering technical performance,environmental impact,and economic performance at the same time,and is the best process for treating UDMH wastewater when the TOC removal rate is 50%.Electrochemical oxidation with BDD electrode as anode has the highest cost and a relatively large environmental burden,but it exhibits the best effect in treating UDMH wastewater.Laboratory experiments have found that 97.75% TOC removal could be achieved with BDD anode,while other three advanced oxidation technologies cannot achieve.Therefore,it is a better choice when only pursuing high removal rate without considering cost. |
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