Chemical speciation, mobility and phyto-accessibility of heavy metals in fly ash and slag from combustion of pelletized municipal sewage sludge

Zhihua Xiao; Xingzhong Yuan; Hui Li; Longbo Jiang; Lijian Leng; Xiaohong Chen; Guangming Zeng; Fei Li; Liang Cao

doi:10.1016/j.scitotenv.2015.07.126

Chemical speciation, mobility and phyto-accessibility of heavy metals in fly ash and slag from combustion of pelletized municipal sewage sludge

Sci Total Environ. 2015 Dec 1:536:774-783. doi: 10.1016/j.scitotenv.2015.07.126. Epub 2015 Aug 4.

Authors

Zhihua Xiao¹, Xingzhong Yuan², Hui Li³, Longbo Jiang¹, Lijian Leng¹, Xiaohong Chen⁴, Guangming Zeng¹, Fei Li⁵, Liang Cao¹

Affiliations

¹ College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
² College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China; Collaborative Innovation Center of Resource-conserving & Environment-friendly Society and Ecological Civilization, Changsha 410083, PR China. Electronic address: yxz@hnu.edu.cn.
³ Institute of Biological and Environmental Engineering, Hunan Academy of Forestry, Changsha 410004, PR China.
⁴ Collaborative Innovation Center of Resource-conserving & Environment-friendly Society and Ecological Civilization, Changsha 410083, PR China.
⁵ College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan 430073, PR China.

PMID: 26254077
DOI: 10.1016/j.scitotenv.2015.07.126

Abstract

Combustion of pelletized municipal sewage sludge (MSS) can generate pestilent byproducts: fly ash and slag. Comparisons of heavy metal sequential extraction results among MSS, fly ash and slag showed that after combustion, the bioavailable heavy metal fractions (acid soluble/exchangeable, reducible and oxidizable fractions) were mostly transformed into the very stable heavy metal fractions (residual fractions). On the other hand, the results of toxicity characteristic leaching procedure (TCLP), diethylenetriamine pentaacetic acid and HCl extraction (phyto-accessibility assessment) demonstrated that the mobility and toxicity of heavy metals were greatly reduced. The direct and long-term bioavailability and eco-toxicity of heavy metals in fly ash and slag were relieved, which implied that combustion of pelletized MSS could be a promising and completely safe disposal technology for MSS treatment.

Keywords: Combustion; Heavy metal; Municipal sewage sludge; Pelletization; Toxicity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Metals, Heavy / chemistry*
Plants / metabolism
Sewage
Soil Pollutants / analysis*
Waste Management / methods*

Substances

Metals, Heavy
Sewage
Soil Pollutants