Solidification/Stabilization of Hospital Waste Incineration Bottom Ash using Ordinary Portland Cement

Solidification/stabilization is an alternative treatment for hazardous and toxic waste materials. The research aims to study solidification/stabilization of bottom ash from hospital incinerator using Ordinary Portland Cement (OPC) and to evaluate the effect of a composition ratio of mortar mixture to heavy metal leaching which influenced by pH, stirring, and leaching time. The rough texture of bottom ash was crushed manually to 4 mm in size, and mortar fabrication was carried out based on the practical instructions for mixing mortar according to ASTM C 305, and mortar molds were prepared based on standard procedures of SNI 03-6825-2002. Leaching test for heavy metals from a mortar sample was carried out by immersing it in 500 mL of aquadest. Results showed that bottom ash from hospital waste incinerator could be mixed with cement as a binder in the solidification/stabilization process. The addition of bottom ash 25-75% of the weight of sand occurred in increased compressive strength. However, the addition of bottom ash greater than 50% by weight of fine aggregate would be reduced the compressive strength of mortar. The compressive strength of all mortar samples of this study met to the standard value (SNI 03-6882-2002). Furthermore, the results of the study showed that there was an influence of changes in pH conditions. These results were indicated by the presence of Cu metal content of 0.0109 mg/L at 50 rpm shaking with pH = 11 and Cu metal content of 0.0101 mg/L at 50 rpm shaking with pH = 7 on mortar baths.