Assessment of possibility of agricultural use of municipal sewage sludge generated in selected small sewage treatment plants from Kraków district

The paper presents the findings from research on physical chemical parameters as well as on microbiological-parasitological municipal sewage sludge from one mediumsized and three small municipal sewage treatment plants from the area of Kraków district. The research was conducted in the years 2007-2012 and aimed at estimating the possibility of agricultural use of the studied sludge. The analyzed sludge turned out to be rich in fertilizing elements, i.e. organic substance, nitrogen, phosphorus, calcium and magnesium. Contents of heavy metals in the analyzed sludge were distinctly lower than the permissible contents in sludge used in agriculture. However, due to frequent occurrence of bacteria from Salmonella group in the studied sludge, its agricultural use may be limited. Relatively high variability in the determined parameters makes it necessary to monitor continuously the sludge coming from particular lots and sewage treatment plants.