Heraklion 2019: 7th International Conference on Sustainable Solid Waste Management

 26-29 June 2019, Heraklion, Greece


Incineration is a common disposal method for sludge management. Sludge ash is an unavoidable by-product of the incineration process that needs to be managed in an environmentally friendly way. The purpose of this study was to investigate the recovery potential of sludge ash, which is generated from the incineration of sewage sludge in a fluidized bed type reactor under 850oC.


Geopolymerization technology was applied to this aim. Sludge ash was combined with cement, fly ash, and marble sludge in different combinations to prepare paste samples without aggregate. NaSilNaOH solution was used as an alkaline activator for geopolymerization. Samples were analyzed for unconfined compressive strength (UCS) after 28 days of air cure.


UCS results of the samples showed that sludge incinerator fly ashes have the potential to be used as supplementary cementitious material in geopolymerization towards obtaining construction materials. An optimum formulation can be obtained for the intended use. Sludge ash was also found to show non-hazardous waste character after being analyzed for the leaching of heavy metals with eluate (EN 12457) solution, which confirms a potential to be safely used in terms of heavy metals.


The UCS and leaching results were found to be promising by the authors for the possible usage of sludge ash after geopolymerization.