【作者】 王欣；

【导师】 樊庆锌；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2019， 硕士

【摘要】 污泥成分复杂,且含水率高,性质不稳定,易对大气、水体、土壤生态环境造成二次污染,因此可通过21世纪国际上公认的最有潜力的环境管理工具LCA对污泥处置不同的技术路线进行环境影响分析,选出最优的技术路线。但对于污泥处置,由于清单变量较多使其清单分析工作繁琐。故本文试图建立改进LCA法,对我国目前广泛应用六条污泥处置技术路线的环境影响进行对比分析,建立预测模型,该结果可为企业工作者提供快速预测污泥处置生命周期总环境影响的方法。运用CML2001的方法,依托GaBi软件,经过LCA传统四个步骤比较分析了六种污泥处置技术路线处理1 t含水率为80%的污泥时的生命周期总环境影响,结果表明,污泥浓缩脱水后经过石灰稳定处理再运送至水泥厂制备水泥是最优的处置方案;污泥处置S1-S6生命周期环境影响贡献较大的处置环节和清单变量依次为:浓缩脱水过程中的电耗(70.16%)、浓缩脱水石灰稳定过程中的电耗(99.67%)、填埋过程中所产生的直接污染物(92.87%)、焚烧过程中所产生的直接污染物(89.76%)、焚烧过程中所产生的直接污染物(89.70%)、土地利用过程中排放的直接污染物(78.38%);从生命周期的角度来看,污泥处置环境影响主要是由于污泥中有害元素的转移(填埋过程重金属的转移、焚烧过程气态物质的转移)造成的,因此应加大污泥的资源化利用率,尽可能固定污泥中的可生成有害物质的元素。运用蒙特卡罗模拟的方法,依托Crystal Ball软件,按照改进LCA中稳定性检验的步骤对污泥处置对生命周期总环境影响潜值的结果进行稳健性检验。污泥处置S1-S6生命周期评价结果的不确定度RSD分别为19.81%、19.88%、23.82%、18.46、18.82%、12.43%均小于25%,污泥处置的LCA的结果是稳定的,可靠的。运用多元线性逐步回归分析法,依托SPSS软件,按照改进LCA中建立预测模型的步骤建立了污泥处置生命周期总环境影响潜值与相关性较大的清单变量的预测模型,即在S1-S6中剔除相关性较小的变量,应用相关性较大的变量来预测污泥处置生命周期总环境影响潜值;探究了目前污泥处置技术生命周期环境影响最小,将来应用可能最为广泛的污泥处置工艺S2的预测模型中预测变量浓缩脱水过程的电耗的范围为1 kWh-12 kWh,欲降低S2生命周期环境影响,可优先改进机械设备、优化运行管理,改善能源结构,选用风能或天然气发电代替混合电网发电。本文建立的改进LCA法,拓宽了LCA的技术框架,可为所有LCA应用领域的研究者提供预测生命周期环境影响的方法思路,且研究结果能够为企业管理者提供简化的生命周期评价法,支持快速决策,促进环保事业的发展。更多还原

【Abstract】 The sewage sludge(SS)has complex composition,large volume and unstable nature.It is easy to cause secondary pollution to the atmosphere,water body,soil ecological environment and human health.So LCA which is the 21 st century internationally recognized most potential environmental management toolc can be used to conducts environmental impact analysis on different technical routes for sludge disposal and selects the optimal technical route.However,for sludge disposal,the inventory analysis is cumbersome due to the large number of inventory variables.Therefore,this paper attempts to establish an improved LCA method.This method is used to compare and analyze the six sludge disposal technical routes in China.This result can provide a way for enterprises to quickly predict the total environmental impact of sludge disposal.Based on the method of CML2001,relying on Ga Bi software,the total environmental impacts of the six sludge disposal technologies on the treatment of sludge with a moisture content of 80% at 1 t are compared through the traditional four steps of LCA.The results showed that the sludge disposal technical route in which the sludge is concentrated and dehydrated,lime stabilized and transported to the cement plant to prepare cement is the best disposal plan;the sludge disposal S1-S6 contributes to the larger disposal link and the characteristic input variables are: the electricity consumption in the concentrated dehydration process(70.16%),the electricity consumption during the stabilization process of dehydrated lime(99.67%),the direct pollutants generated during the landfill process(92.87%),the direct pollutants generated during the incineration process(89.76%),and the direct pollution generated during the incineration process(89.70%),direct pollutants discharged during land use(78.38%);from the perspective of life cycle,in order to reduce the environmental impact of sludge disposal,we should first increase the utilization rate of sludge,fix some harmful elements in the sludge,reduce its transfer,and secondly use the electricity generated by wind or natural gas.Based on the Monte Carlo stochastic simulation method,relying on the Crystal Ball software,the robustness test was carried out on the results of the sludge treatment on the total environmental impact of the sludge disposal life cycle according to the stability test procedure in the improved LCA.The uncertainty RSD of sludge disposal S1-S6 is 19.81%,19.88%,23.82%,18.46,18.82%,12.43% and they are less than 25%,respectively.The result of LCA for sludge disposal is stable and reliable.Using the multivariate linear stepwise regression analysis method,based on the SPSS software,according to the steps of establishing the prediction model in the improved LCA,the inventory environmental impact potential value prediction models of S1-S6 of SS treatment with large correlation are established.Eliminate the less relevant variables,apply the relevant predictive variables to predict the total environmental impact potential of the sludge disposal life cycle;and minimize the impact on the current sludge disposal technology life cycle environment.The predictive variable during the concentration and dehydration process of S2 is from 1 k Wh to 12 k Wh.To reduce the environmental impact of S2,it is possible to prioritize the improvement of mechanical equipment,optimize operation management,improve energy structure,and replace hybrid grid power generation by wind power or natural gas power generation.The improved LCA method established in this paper broadens the technical framework of LCA and simplifies the LCA process,providing a simplified and predictive approach for researchers in all LCA applications.The analysis and prediction of the environmental impact of sludge disposal by this method can provide decision support for managers and promote the development of regional environmental protection.更多还原