CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Xin Yang,Lu Yao,Yu Wang,Xinran Zhang,Pengfei Ren
Algae blooms can clog filtration tank, release toxic cyanotoxin and produce undesirable disinfection byproducts (DBPs) in post-chlorination, which brings challenges to conventional water treatment processes. In this study, peroxymonosulfate (PMS) was tested for its ability to improve Fe(III) coagulation of Microcystis aeruginosa in water treatment. Compared with conventional Fe(III) coagulation, the presence of PMS resulted in the formation of larger floc and thus better algae and turbidity removal. The removal of algae by PMS-enhanced Fe(III) coagulation (PMS-Fe(III)) process reached 97.5% at 1 mM PMS, which was 1.5 times higher than that by Fe(III) coagulation alone. The oxidization of surface-adsorbed extracellular organic matter destabilized the algal cells and enhanced their coagulation without greatly damaging the cells’ integrity. Simultaneously, about 80% of Microcystin-LR, a cyanotoxin, was degraded in the enhanced process. Moreover, the formation of DBPs and their associated toxicity during the subsequent chlorination were decreased by 49.2% and 13.6%, respectively. The production of trihalomethanes, haloacetic acids and haloacetronitriles was particularly abated. SO 4 •- and HO • , which were formed from PMS activation through redox cycling of Fe mediated by the existing natural organic matter, were mainly responsible for algae removal. The results indicate that supplementing Fe(III) coagulation with PMS is a promising option for treating water during algal blooms.
研究领域:
环境科学
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水处理工程
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Nannan Geng,Yili Wang,Daxin Zhang,Xiaoyang Fan,Enrui Li,Zhibo Han,Xiaoqi Zhao
As a by-product of wastewater treatment , waste activated sludge (WAS) has complex composition, strong hydrophilic extracellular polymeric substance (EPS), which make it difficult to dewater. In this study, an electro-peroxone oxidation-Fe(III) coagulation (E-peroxone-Fe(III)) sequential conditioning approach was developed to improve WAS dewaterability. At E-peroxone oxidation stage, hydrogen peroxide was generated through 2-electron path on a carbon polytetrafluoroethylene cathode, and reacted with the sparged O 3 to produce hydroxyl radicals . At the subsequent coagulation stage, Fe(III) was dosed to coagulate the small WAS fragments and release water from WAS. Along E-peroxone-Fe(III) subsequent conditioning process, the physicochemical properties of WAS, main components, functional groups and evolution of protein secondary structure, and typical amino acids in EPS, as well as the type and semi-quantitative of elements in WAS, were investigated. The results indicated that under the optimal conditions, the reductions of specific resistance to filterability (SRF) and capillary suction time (CST) for WAS equalled 78.18% and 71.06%, respectively, and its bound water content decreased from 8.87 g/g TSS to 7.67 g/g TSS. After E-peroxone oxidation, part of protein and polysaccharide migrated outside from TB-EPS to slime, the ratio of α-helix/( β -sheet + random coil) declined, even some of organic-N disintegrated to inorganic-N. At Fe(III) coagulation stage, re-coagulation of the dispersed WAS fragments and easy extraction from inner EPS for protein and polysaccharide occurred. Furthermore, the protein secondary structure of β -sheet increased by 13.48%, the contents of hydrophobic and hydrophilic amino acids also increased. In addition, a strong negative correlation between the hydrophobic amino acid content of Met in slime and CST or SRF ( R 2 CST = −0.999, p < 0.05 or R 2 SRF = −0.948, p < 0.05) occurred, while a strong positive correlation between the hydrophilic amino acid content of Cys in TB-EPS and CST or SRF ( R 2 CST = 0.992, p < 0.05 or R 2 SRF = 0.921, p < 0.05) occurred, which could be related to the WAS dewaterability.
研究领域:
环境工程
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污水处理
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污泥管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）