Insight into dewatering behavior and heavy metals transformation during waste activated sludge treatment by thermally-activated sodium persulfate oxidation combined with a skeleton builder-wheat straw biochar

被引:24
|
作者
Guo, Junyuan [1 ]
Gao, Qifan [1 ]
Jiang, Shilin [1 ]
机构
[1] Chengdu Univ Informat Technol, Coll Resources & Environm, Chengdu 610225, Sichuan, Peoples R China
关键词
Thermally; Sodium persulfate; Biochar; WAS dewatering; Heavy metals; SEWAGE-SLUDGE; PEROXYMONOSULFATE OXIDATION; DEWATERABILITY; PRETREATMENT; ENHANCEMENT; RISK; FATE; IRON;
D O I
10.1016/j.chemosphere.2020.126542
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
This work focused on dewatering performance and heavy metals (HMs) transformation during waste activated sludge (WAS) treatment by employing thermally-activated sodium persulfate (SPS) oxidation combined with a biochar made of wheat straw (WS-BC). Results demonstrated that the combined treatment was an efficient way to improve WAS dewatering, especially when SPS and WS-BC dosages were adjusted to 120 and 150 mg/g-volatile solids (VS), respectively. After being treated at 70 degrees C without pH adjustment, standardized-capillary suction time (SCST) was increased to 5.03, centrifuged weight reduction (CWR) was increased to 86.8% and moisture content (MC) was decreased to 42.6%, indicating an excellent dewatering performance. The underlying mechanism identified were: (1) SPS oxidation disintegrated extracellular polymers (EPS) at high temperature, thereby releasing EPS-bound water; (2) WS-BC acted as a skeleton builder conducive to form porous structure and provide free water release channels in WAS, which was favorable to improve dewatering properties of WAS; (3) thermally-activated SPS oxidation significantly improved the solubilization and reduced the leaching toxicity of HMs in WAS; and (4) the following WS-BC treatment further reduced the leaching toxicity of HMs in WAS. Therefore, the combined technology might be a promising strategy to improve WAS dewatering and reduce HMs risks in WAS. (C) 2020 Elsevier Ltd. All rights reserved.
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页数:10
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