Environmental Impact Analysis Of Sludge Disposal Based On Improved LCA

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.