Life Cycle Assessment application to treatment and disposal of sludge from a wastewater treatment plant

The following study uses Life Cycle Assessment as a tool to determine the impacts generated by the treatment of sludge from municipal wastewater treatment plants (EWC 190805). In this paper, four scenarios of technologies used for sludge disposal are presented: scenario A considers dewatered and undigested sludge sent to landfill; in scenario B the sludge undergoes a stabilization process for use on land; scenario C considers incineration of the dried sludge; and in scenario D the sludge undergoes the same treatment as in scenario B but for final use as compost. The system boundaries include transport to the various disposal centers, using functional units equal to one ton of dried sludge. House made software was used to calculate the impacts, using input data from an existing plant located in central Italy. The environmental categories analyzed were global warming potential, acidification potential and eutrophication potential. The results per functional unit indicate that land application has the lowest GWP impact, while incineration without recovery produces the highest. The analysis was then extended to the national level with data from the ISPRA database. Research using LCA can be useful for decision-makers and stakeholders on strategies to improve environmental performance on the topic.