Thermal utilization and agricultural use of sewage sludge in Poland

According to the Polish law, sewage sludge is regarded as a waste and in 95% is stored on a disposal sites after previous dewatering. Poland belongs to the group of European countries that hardly utilize sewage sludge as a resource. Only 0.5% of sewage sludge undergoes thermal treatment by incineration or co-incineration with other waste, of which sewage sludge comprises only a slight amount. Only 4.5% of sewage sludge is used as a valuable fertilizer to agricultural and natural purposes, which puts us at the bottom of the list of European countries in relation to utilization of such sludge as a valuable source of biogenic elements. In the paper the general characteristic of sewage sludge in the aspects of its potential thermal, agricultural and natural usage is presented. On the example of three wastewater treatment plants the final utilization of sewage sludge together with its thermal treatment and burning in one of the plants is characterized. Examinations of analyzed sludge from two wastewater treatment plants displayed the possibility of application of the sewage sludge to cultivation of non-comestible plants or reclamation of degraded land. High content of organic compounds and adequately low final hydration of sewage sludge from examined wastewater treatment plant created the possibility of its burning and co-burning, which is presented in the paper.