Reuse of waste sulfur from biogas desulfurization for potentially toxic metals stabilization in MSWI fly ash towards zero-waste in venous industry park

Waste recycling in venous industrial park is considered to be an effective way for circular economy. However, the reuse of waste sulfur from biogas desulfurization in the park is difficult, and this problem has attracted little attention, leading to waste of resources and pollution. In this study, a stabilizer based on waste sulfur from biogas desulfurization (SBD) was prepared for stabilization of potentially toxic metals in municipal solid waste incineration (MSWI) fly ash (FA) using a simple hot alkali synthesis method. Results showed that the stabilization effect of SBD on the four commercial agents (Na2S, Amm-DTC, PBD-A and PBD-B) were significantly improved. Using 3% SBD+ 3% PBD-A, the excess Pb, Cd and Ni in the original fly ash could reach the landfill standard, and the stabilization efficiency reached 100%, 100%, and 93%, respectively, with treatment cost of 34-50 USD/t (246-366 RMB/t); compared with the single commercial agent (5% PBD-A), the stabilization efficiency of Pb was improved by 13% and the treatment cost was saved by 39%. These results provide an economical and environmentally friendly way to realize the co-disposal of MSWI FA and waste sulfur from biogas desulfurization in the park.