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| Immobilization and Its Influencing Factors of Heavy Metals During Composting of Sewage Sludge |
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| KeyWord:sewage sludge; compost; heavy metal forms; correlation analysis |
| Author Name | Affiliation | | GE Xiao | College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China | | BIAN Xin-zhi | College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China | | WANG Yan | Jiangsu Institute of Agricultural Sciences in the Lixiahe District, Yangzhou 225007 | | ZHANG Sheng-hua | College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China | | CHU Yan-chun | College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China | | DING Jing | College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China | | WANG Xiao-zhi | College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China | | FENG Ke | College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China |
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| Abstract: |
| Contents and bioavailability of heavy metals in municipal sewage sludges are the main factors limiting their agricultural uses. This study examined changes and their influencing factors of various forms of heavy metals at different stages during sewage sludge composting processes using BCR sequential extraction method. Cu, Ni, Cr and Pb, except Zn and Cd, in sewage sludge were mainly in an oxidation state and residual state, with low bioavailability. Composting processes significantly reduced the bioavailability of heavy metals, and altered the distribution of heavy metals among various forms, transforming acid-soluble and reducible heavy metals into more stable forms, oxidation state（OXI） and residual state（RES）. Residual fraction of Cu, Zn, Ni, Cd, Cr and Pb at the end of the composting increased by 6.3%, 6.7%, 22.0%, 15.2%, 11.0% and 40.5%, respectively, compared with those at the beginning of the process. Heavy metal forms were significantly correlated with DOC content, but not with OM. pH mainly affected distribution of reducible and bioavailable fractions of heavy metals. |
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