Migration and risk assessment of heavy metals in sewage sludge during hydrothermal treatment combined with pyrolysis.
In this study, the immobilization and risk assessment of heavy metals (HMs) in sewage sludge (SS) during hydrothermal treatment combined with pyrolysis (HTP) was investigated. The experimental results showed that the immobilization of HMs in SS was significantly affected and that the eco-toxicity/risk of SS to the environment was reduced through HTP, in addition to the enhancement of dehydration and a reduction in the volume of the sewage sludge. After the HTP process, although the majority of HMs were accumulated in the biochar, the HMs could be transformed from bioavailable fractions to more stable fractions, such as the acid soluble/exchangeable fractions (F1) of Zn, Ni and Cd in the biochar, which decreased to less than 6.31%, 2.36% and 3.64%, respectively. Moreover, the leaching potential of HMs decreased after the HTP process.
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China.
Xingdong
X
Wang
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China.
Chunxing
C
Li
Xiamen ZKCH New Energy and Environment Co. LTD, Xiamen 361021, PR China.
Bin
B
Zhang
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China.
Jingjiang
J
Lin
Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China.
Qiaoqiao
Q
Chi
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China. Electronic address: yinwang@iue.ac.cn.
Yin
Y
Wang
D002606:Charcoal; D006358:Hot Temperature; D019216:Metals, Heavy / Q000737:chemistry*; D018570:Risk Assessment; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
D019216:Metals, Heavy; D012722:Sewage; C540010:biochar; D002606:Charcoal
Heavy metals (HMs); Hydrothermal treatment (HTT); Pyrolysis; Risk assessment; Sewage sludge