engleski

MANAGEMENT OF SEWAGE SLUDGE - NEW INSIGHT INTO VALORISATION AS SUPPLEMENTARY CEMENTITIOUS MATERIAL

Wastewater treatment and management of the generated by-products has become a very important global problem which is specially the case in developing countries like Croatia, where the number of wastewater treatment plants (WWTP) is increasing to meet stringent EU requirements. This is resulting in the production of increasing quantities of sewage sludge. Thermal processing of sewage sludge can facilitate its further management by reducing the total mass and volume. Sewage sludge ash (SSA) is the main by-product formed in the combustion processes. Most of the generated SSA worldwide is still landfilled but this is a significant additional cost for utilities since it is usually classified as a non-hazardous waste depending on a results of leaching tests. Therefore, use of SSA is desirable and it may be possible to use it in the concrete industry as a partial cement replacement. This is because the main chemical elements present in Portland cement (Ca, Si, Al and Fe) are also present in SSA. The research presented in this paper is part of a wider feasibility study on the possible recycling and use of Croatian sewage sludge ash. Sewage sludge was sourced from WWTP Karlovac and SSA was produced by laboratory incineration at temperatures of 800 and 900°C. The possibility of SSA use depends a great deal on its composition so physical and chemical characteristics of SSA were investigated.

sewage sludge ash ; incineration ; cement ; strength ; leaching

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