The slag original from the process of sewage sludge incineration selected properties characteristic

¹ EDP Department of Sanitary Engineering West Pomeranian University of Technology in Szczecin, al. Piastów 50, 70-311 Szczecin, Poland
² EDP Department of Building Physics and Building Materials West Pomeranian University of Technology in Szczecin, al. Piastów 50, 70-311 Szczecin, Poland

^* Corresponding author: anna.izewska@zut.edu.pl

Abstract

This work characterizes the physical and chemical properties of slag from combustion of municipal sewage sludge in “Pomorzany“ waste treatment plant in Szczecin. The technology of sludge management is based on drying the sludge in low-temperature belt driers, to a content level of at least 90%, dry mass., and then burning in a grate boiler with mobile grate. The research of the slag resulting from combustion of municipal sewage sludge was conducted using reference methods, presenting images from a scanning electron microscope. The tested waste contained from 16.300 to 23.150% P₂O₅ completely soluble in strong acids, pH 8.03, mineral substance 98.73% dry mass. The content of heavy metals did not exceed the permissible amount specified in the Regulation of the Minister of Agriculture and Rural Development of 18 June 2008 on the implementation of certain provisions of the Act on fertilizers and fertilization (Journal of Laws of 2008 No. 119, item. 765). The screening trials showed that 48.4% are fractions of 630 µm–1.25 mm. The results show that the waste code 19 01 12 may be used as: alternative source of phosphorus for direct application to soil treatment, for production of organic – mineral fertilizers and as construction aggregate for production of concrete mortars.