Testing properties of sewage sludge for energy use

The properties of sewage sludge in the context of their further energy use have been examined. For this purpose, 34 samples of sewage sludge from municipal sewage treatment plants from the area of Lower Silesia with a capacity higher than the 2000 population equivalent (PE) with separate sludge management were tested. As part of the study, tests were made to determine the technological usefulness of fuels and their elemental composition, i.e., technical analyses and elemental analyses. The obtained results show a large diversity of basic physicochemical properties of the tested sewage sludge. The share of volatile components important for energetic use ranged from 38.4 to 59.8 wt. %. The content of carbon (C) in the mass of tested sewage sludge ranged from 22.4 to 39.2 wt. %, which means that they have a lower content of elemental carbon compared to solid fuels. The higher heating value (HHV) of sewage sludge ranged from 9.3 to 17.4 MJ/kg dry mass.