Thermal processing of sewage sludge – II

This paper is focused on heat and economic aspects of selected sludge management options. Sewage sludge produced by waste water cleaning process is biodegradable material with growing production. This paper compares three alternative technologies of sludge management where sludge is used to produce energy. Alternative 1 considers anaerobic digestion of mixed raw sludge with subsequent cogeneration of obtained biogas. Alternative 2 covers incineration of mixed raw sludge utilizing energy contained in flue gases. Alternative 3 represents a combination of the above two alternatives – incineration of digested sludge utilizing energy contained in biogas and flue gas. Heat and economic balances were performed on the basis of the pilot tests of sludge dewatering at a big waste water treatment plant with the aim to use credible data for all the analyses. Therefore results provide information of practical value.