Utilization of sewage sludge from food industry wastewater treatment plants

The Podlasie Region is an agricultural area with dominating food industry. As many as 14 out of 100 biological WWTP in the region receive sewage from food industry. Modernization of the treatment systems, performed at the end of 1990s in order to improve nutrients removal effectiveness, resulted in the increase of the sewage sludge amount. The possibility of sewage sludge recycling to the environment, for instance as a fertilizer, depends on its physical-chemical composition and sanitary quality. Polish legislatory requirements define the conditions that have to be fulfilled before the sludge may used for soil fertilization. In the article the results of analyses of the sludge generated in two largest industrial WWTPs in the region, as well as problems concerning sludge processing and final utilization, are presented.