Solidification and Biotoxicity Assessment of Thermally Treated Municipal Solid Waste Incineration (MSWI) Fly Ash

Bing Gong, Yi Deng, Yuanyi Yang, Swee Ngin Tan, Qianni Liu and Weizhong Yang
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Bing Gong: School of Materials Science and Engineering, School of Chemical Engineering, Sichuan University, Chengdu 610065, China
Yi Deng: School of Materials Science and Engineering, School of Chemical Engineering, Sichuan University, Chengdu 610065, China
Yuanyi Yang: Department of Materials Engineering, Sichuan College of Architectural Technology, Deyang 618000, China
Swee Ngin Tan: National Sciences and Science Education, National Institute of Education, Singapore 637616, Singapore
Qianni Liu: School of Materials Science and Engineering, School of Chemical Engineering, Sichuan University, Chengdu 610065, China
Weizhong Yang: School of Materials Science and Engineering, School of Chemical Engineering, Sichuan University, Chengdu 610065, China

IJERPH, 2017, vol. 14, issue 6, 1-10

Abstract: In the present work, thermal treatment was used to stabilize municipal solid waste incineration (MSWI) fly ash, which was considered hazardous waste. Toxicity characteristic leaching procedure (TCLP) results indicated that, after the thermal process, the leaching concentrations of Pb, Cu, and Zn decreased from 8.08 to 0.16 mg/L, 0.12 to 0.017 mg/L and 0.39 to 0.1 mg/L, respectively, which well met the limits in GB5085.3-2007 and GB16689-2008. Thermal treatment showed a negative effect on the leachability of Cr with concentrations increasing from 0.1 to 1.28 mg/L; nevertheless, it was still under the limitations. XRD analysis suggested that, after thermal treatments, CaO was newly generated. CaO was a main contribution to higher Cr leaching concentrations owing to the formation of Cr (VI)—compounds such as CaCrO 4 . SEM/EDS tests revealed that particle adhesion, agglomeration, and grain growth happened during the thermal process and thus diminished the leachability of Pb, Cu, and Zn, but these processes had no significant influence on the leaching of Cr. A microbial assay demonstrated that all thermally treated samples yet possessed strong bactericidal activity according to optical density (OD) test results. Among all samples, the OD value of raw fly ash (RFA) was lowest followed by FA700-10, FA900-10, and FA1100-10 in an increasing order, which indicated that the sequence of the biotoxicity for these samples was RFA > FA700-10 > FA900-10 > FA1100-10. This preliminary study indicated that, apart from TCLP criteria, the biotoxicity assessment was indispensable for evaluating the effect of thermal treatment for MSWI fly ash.

Keywords: MSWI fly ash; thermal treatment; toxicity characteristic leaching procedure (TCLP); microbial assay (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2017
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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