Performance of calcium peroxide for removal of endocrine-disrupting compounds in waste activated sludge and promotion of sludge solubilization.
Performance of calcium peroxide for removal of endocrine-disrupting compounds in waste activated sludge and promotion of sludge solubilization.
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DOI：
10.1016/j.watres.2015.01.005
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发表时间：
2015-03
期刊：
影响因子：
12.8
通讯作者：
Ai Zhang;Jie Wang;Yongmei Li
中科院分区：
文献类型：
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作者：
Ai Zhang;Jie Wang;Yongmei Li
采用过氧化钙(CaO_2)氧化法对废弃活性污泥中6种酚类内分泌干扰物(雌酮、17-β-雌二醇、17-α-雌二醇、雌三醇、双酚A和4-壬基酚)进行了去除研究。考察了初始pH和CaO_2投加量的影响。此外，还考察了CaO2处理对污泥溶解和厌氧消化的影响。具体地说，考察了活性氧物种(ROS)在CaO2氧化过程中对EDC降解的作用。同时考察了污泥基质中6种金属离子对EDC降解的影响。结果表明，CaO2处理是一种很有前途的去除EDC和促进污泥再利用的技术。EDC的去除效率随CaO2投加量的增加而提高。当投加量大于0.34g/g总固体(g/g−1TS)时，在较宽的pH范围内，EDCs的降解率可达50%以上。初始pH为12和2时，EDCs的降解率较高。在中性pH和CaO2投加量为0.34 mg/g−1TS的条件下，污泥的溶解度在7d内分别提高了25%和27%，挥发性脂肪酸的产量在厌氧消化后的15d内提高了96%。CaO2释放的ROS是影响EDC去除的主要因素，其中羟基自由基(DotOH)起着最重要的作用。污泥基质中的金属离子对EDC的去除也有影响。在大多数情况下，铁、铜和锌对EDC的去除有正作用，锰和银有负作用，而镁对EDC的去除作用不明显。
Removal of six phenolic endocrine disrupting compounds (EDCs) (estrone, 17β-estradiol, 17α-ethinylestradiol, estriol, bisphenol A, and 4-nonylphenols) from waste activated sludge (WAS) was investigated using calcium peroxide (CaO2) oxidation. Effects of initial pH and CaO2dosage were investigated. The impacts of CaO2treatment on sludge solubilization and anaerobic digestion were also evaluated. Specifically, the role of reactive oxygen species (ROS) in EDC degradation during CaO2oxidation was tested. Effects of 6 metal ions contained in the sludge matrix on EDC degradation were also evaluated. The results showed that CaO2treatment can be a promising technology for EDC removal and facilitating sludge reuse. The EDC removal efficiencies increased with the increase in CaO2dosage. At CaO2doses of more than 0.34 g per gram of total solid (g g−1TS), more than 50% of EDCs were removed in a wide pH range of 2–12. Higher removal efficiencies were achieved at initial pH values of 12 and 2. The products of EDCs during CaO2oxidation had less estrogenic activity than the originals. Under the conditions of neutral pH and CaO2dosage = 0.34 g g−1TS, the sludge solubilization can be improved by increasing the soluble total organic carbon (STOC) and volatile suspended solids (VSS) reduction by 25% and 27% in 7 d, respectively; the volatile fatty acid (VFA) production was enhanced by 96% in the 15 d following anaerobic digestion. The ROS released by CaO2are the main factors contributing to EDC removal, among which, hydroxyl radicals (radical dotOH) play the most important role. Metal ions contained in the sludge matrix also affected EDC removal. For most cases, Fe, Cu, and Zn had positive effects; Mn and Ag had negative effects; and Mg had an insignificant effect on EDC removal.