Solidification of SSS (sewage sludge slag) has been carried out by the geopolymer binder technique at 80°C steam conditions mixed with CFA (coal fly ash). Geopolymer liquor was prepared by mixing Na-disilicate solution of 1.27 S.G. (specific gravity) and 10 M NaOH solution in 3:1 proportion. Obtained monolithic materials were subjected to physical measurements such as 3-point flexural strength, bulk density and expansion-shrinkage. Subsequently, matrix as well as filler chemical compositions were analyzed by SEM-EDX. Results showed SSS is an active filler similar to CFA and maximal strength was reached by blending SSS with CFA in 1:3 proportion. P₂O₅ and CaO components of SSS strongly contributed to the polycondensation of the geopolymer liquor other than theoretically expected Al₂O₃ and SiO₂ components.