Risk assessment of heavy metals from combustion of pelletized municipal sewage sludge.
Fly ash and slag are important by-products obtained from combustion of municipal sewage sludge (MSS) after pelletization. The quantitative environmental impact assessment of heavy metals in fly ash and slag, compared to MSS, were performed in accordance with bioavailability and eco-toxicity, geo-accumulation index (GAI), risk assessment code (RAC), and potential ecological risk index (PERI). The results demonstrated that not only direct but also long-term bioavailability and eco-toxicity of heavy metals in fly ash and slag decreased except direct bioavailability and eco-toxicity of Pb in fly ash. The GAI demonstrated that combustion significantly weakened (P < 0.05) the pollution levels of heavy metals. PERI indicated that all risks attributed to heavy metals were significantly lowered (P < 0.05) from 777.07 (very high risk) in MSS to 288.72 (moderate risk) and 64.55 (low risk) in fly ash and slag, respectively. In terms of the RAC, seven heavy metals had low even no risk to the environments after combustion besides As in slag. The environmental risk of heavy metals in fly ash and slag was decreased compared with MSS. However, the results of PERI showed that fly ash had a moderate risk.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.|Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, People's Republic of China.
Zhihua
Z
Xiao
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China. yxz@hnu.edu.cn.|Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, People's Republic of China. yxz@hnu.edu.cn.|Collaborative Innovation Center of Resource-Conserving and Environment-Friendly Society and Ecological Civilization, Changsha, 410083, People's Republic of China. yxz@hnu.edu.cn.
Xingzhong
X
Yuan
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.|Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, People's Republic of China.
Lijian
L
Leng
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.|Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, People's Republic of China.
Longbo
L
Jiang
Collaborative Innovation Center of Resource-Conserving and Environment-Friendly Society and Ecological Civilization, Changsha, 410083, People's Republic of China.
Xiaohong
X
Chen
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.|Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, People's Republic of China.
Wu
W
Zhibin
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.|Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, People's Republic of China.
Peng
P
Xin
College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, People's Republic of China.
Zhang
Z
Jiachao
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.|Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, People's Republic of China.
Guangming
G
Zeng
D060729:Coal Ash; D004787:Environmental Pollution; D005390:Fires; D019216:Metals, Heavy / Q000032:analysis*; D018570:Risk Assessment; D012722:Sewage
D060729:Coal Ash; D019216:Metals, Heavy; D012722:Sewage
Combustion; Heavy metal; Municipal sewage sludge; Pelletization; Risk assessment