Synergistic Passivation of Fly Ash and TMT on Heavy Metals in Sewage Sludge

Dong-Fang Wang, Shi-He Li, Xian-Qing Wang, Ling-Xu Li and Xuan Zhang
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Dong-Fang Wang: College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan 250353, China
Shi-He Li: College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan 250353, China
Xian-Qing Wang: College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan 250353, China
Ling-Xu Li: College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan 250353, China
Xuan Zhang: College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan 250353, China

Sustainability, 2018, vol. 10, issue 12, 1-17

Abstract: Large amounts of fly ash and sewage sludge are produced annually in China. The treatment and disposal of such byproducts have become urgent problems that need to be solved. In order to achieve the possibility of realizing land applications for sewage sludge, fly ash and trimercapto-s-triazine trisodium salt (TMT) were used as immobilizing agents, and their passivation effects on four kinds of heavy metals (Cu, Ni, Pb, and Zn) were evaluated. The results showed that the resulting sewage sludge met Chinese standard GB/T23486-2009. When the addition was 10–20% fly ash or 0.4–0.6% TMT, the optimum immobilization effect was obtained. The synergistic passivation of 20% fly ash +0.5% TMT was superior to that of either fly ash or TMT alone. The addition of sewage sludge during the ryegrass growth process significantly increased the plant height, the number of tillers, the chlorophyll content, and the biomass of the ryegrass over the brown soil. The adverse effect of the heavy metals on the ryegrass growth could be alleviated by the passivation effect of fly ash and TMT. The immobilization performance of the fly ash was mainly due to the formation of precipitation and the ion exchange, while that of TMT was due to chelate precipitation.

Keywords: heavy metals; sewage sludge; fly ash; trimercapto-s-triazine trisodium salt; immobilization (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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