Pollution concerns on land use of sewage sludge from municipal wastewater treatment plants

Land application of sewage sludge is still a widespread practice in Italy: from Italian Decree of 1992 large amounts of sludge were applied to soils without changing parameters or setting limit values for new pollutants. This work considered a typical territorial wastewater \u2013 sludge management system for small suburban communities located in the north \u2013 east of Italy and aimed to characterize the level of pollution of both sewage sludge and soils interested by continuous and repeated applications, following the suggestions of the last official document of European Union about sewage sludge: the Working document on sludge (3rd draft, 2000). Results showed that sewage sludge from domestic and urban wastewater treatment plants are characterized by a ground level of heavy metals and organic pollutants contamination, without significant differences on the basis of type of wastewater, treatment technologies and plant capability. This work considered also inorganic pollution of soils evaluating the average amount of each heavy metal applied annually. The comparison of results with limit values proposed by the draft showed a moderate content of inorganic pollutants, but we highlighted a predictable enrichment in heavy metals content of soils