Properties and environmental safety of cement-solidified fat-containing municipal solid waste incineration fly ash

Dioxins are highly lipophilic. Based on this property, porcine fat (FP) can be used to separate dioxins from municipal solid waste incineration fly ash (MSWIFA). The resulting MSWIFA treatment product (MSWIFA-TP) exhibits a substantially reduced dioxin toxic equivalent (TEQ). In this study, cement-solidified MSWIFA-TP was evaluated to assess its potential for resource utilization. The effects of residual fat in MSWIFA-TP on the strength development, mineralogical composition, and pore structure of the solidified bodies were investigated. The results showed that the incorporation of MSWIFA-TP promoted the formation of calcium fatty acid salts within the solidified matrix. These salts exerted a pore-filling effect, thereby increasing the compactness of the solidified matrix. Leaching tests showed that both heavy metals concentrations and the estimated dioxin release remained below the relevant Chinese regulatory limits. These findings demonstrate the feasibility of cement solidification for the resource utilization of MSWIFA-TP and suggest a potential treatment strategy for other oily and fat-containing sludges.