Enhanced dewaterability of sewage sludge with zero-valent iron-activated persulfate oxidation system

The potential benefits of zero-valent iron-activated persulfate (Na2S2O8) oxidation in enhanced dewaterability of sludge, along with the associated mechanisms were investigated in this study. The sludge dewaterability was evaluated in terms of specific resistance to filtration (SRF) and water content. Based on these indexes, it was observed that ZVI-S2O82 oxidation effectively improved sludge dewaterability. The optimal conditions to give preferable dewaterability were found when the molar ratio of ZVI/S2O82− was 5:1 and pH value was 3.0. The most important mechanism was proposed to be the degradation of extracellular polymeric substances (EPS) incorporated in sludge flocs and rupture of microbial cells. Three-dimensional excitation–emission matrix fluorescence spectra revealed that the powerful SO4− and ·OH generated from ZVI-S2O82− system destroyed the particular functional groups of ﬂuorescing substances (aromatic protein-like and tryptophan protein-like substances), resulting in the release of bound water and the subsequent enhancement of dewaterability. Therefore, ZVI/S2O82− oxidation is an alternative approach showing great potential to be applied in sludge treatment plants.

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Performance and mechanism of sludge dewaterability enhanced by potassium ferrate pretreatment and calcium chloride addition

Journal of Water Reuse and Desalination ◽

10.2166/wrd.2016.147 ◽

2016 ◽

Vol 7 (2) ◽

pp. 136-141 ◽

Cited By ~ 5

Author(s):

Yali Liu ◽

Xiaorong Kang ◽

Xin Li ◽

Zheng Wang ◽

Zhaoqian Jing

Keyword(s):

Calcium Chloride ◽

Extracellular Polymeric Substances ◽

Three Dimensional ◽

Negative Relationship ◽

Potassium Ferrate ◽

Optimal Parameters ◽

Capillary Suction ◽

Potential Benefits ◽

Sludge Dewaterability ◽

Microscopy Images

The potential benefits and mechanisms of potassium ferrate pretreatment and calcium chloride addition on sludge dewaterability were investigated in this study. The capillary suction time (CST) was used to evaluate sludge dewaterability. Results indicated that potassium ferrate of 0.1 g/g total solids (TS) and calcium chloride of 0.4 g/g TS were optimal parameters, and corresponding CST reached 43.7 s. Soluble organics in extracellular polymeric substances (EPS) were determined by three-dimensional excitation-emission matrix fluorescence spectroscopy, which was used to explain the mechanism of sludge dewaterability. The fluorescence intensities of protein-like and humic-like substances in EPS had a negative relationship with the CST. Scanning electron microscopy images indicated that calcium chloride neutralized the surface charge of particles, making the soluble protein-like substances agglomerate and form bigger flocs, consequently enhancing sludge dewaterability.

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Improvement of sludge dewaterability and disintegration efficiency using electrolytic zero-valent iron activated peroxymonosulfate

Water Science & Technology ◽

10.2166/wst.2021.229 ◽

2021 ◽

Author(s):

Shaodong Guo ◽

Yuxin Huang ◽

Long Zhou ◽

Xinghu Huang

Keyword(s):

Extracellular Polymeric Substances ◽

Specific Resistance ◽

Three Dimensional ◽

Oxygen Demand ◽

Ammonia Nitrogen ◽

Zero Valent Iron ◽

Organic Substances ◽

Fluorescence Excitation ◽

Capillary Suction ◽

Sludge Dewaterability

Abstract Electrolysis zero-valent iron activated peroxymonosulfate (EZVI-PMS) was applied to enhance sludge dewaterability and disintegration performance. Sludge dewaterability was characterized by capillary suction time (CST), specific resistance to filtration (SRF), and disintegration performance was explored by measuring sludge DNA content, ammonia nitrogen, chemical oxygen demand (COD), extracellular polymeric substances (EPS) and dissolved organic carbon (DOC). EPS including soluble EPS (SB-EPS), loosely bound EPS (LB-EPS), tightly bound EPS (TB-EPS) were analyzed by three dimensional fluorescence excitation-emission spectrum (3D-EEM) to confirm the proteins transformation tendency. DOC, protein and polysaccharide in EPSs were quantified to investigate the conditioning mechanism. The results showed that sludge CST and SRF were reduced significantly when the current was 0.2 A and PMS dosage was 130 mg/gDS with the reductions of 43.8% and 74.1%, respectively, and DNA was released from sludge cells to liquid phase. Mechanically, sludge TB-EPS converted to SB-EPS with DOC in TB-EPS decreasing from 367.0 mg/L to 210 mg/L, while DOC in SB-EPS increased from 44 mg/L to 167.4 mg/L. Besides, the changes of proteins and polysaccharides contents in SB-EPS and TB-EPS were similar to DOC, and protein in TB-EPS transformed to other protein-like or organic substances obviously.

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Trichloroethylene Degradation by Zero Valent Iron Activated Persulfate Oxidation

Environmental Engineering Science ◽

10.1089/ees.2007.0174 ◽

2008 ◽

Vol 25 (7) ◽

pp. 1071-1078 ◽

Cited By ~ 102

Author(s):

Chenju Liang ◽

Ming-Chun Lai

Keyword(s):

Zero Valent Iron ◽

Persulfate Oxidation ◽

Trichloroethylene Degradation ◽

Activated Persulfate

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Insight into the comparison of thermally and Fe(II) activated persulfate on sludge dewaterability and disintegration

Water Science & Technology ◽

10.2166/wst.2021.337 ◽

2021 ◽

Author(s):

Shaodong Guo ◽

Long Zhou ◽

Yuxin Huang ◽

Xinghu Huang

Keyword(s):

Extracellular Polymeric Substances ◽

Three Dimensional ◽

Oxygen Demand ◽

Ammonia Nitrogen ◽

Fluorescence Excitation ◽

Capillary Suction ◽

Extracellular Polymer Substance ◽

Sludge Dewaterability ◽

Oxidation Efficiency ◽

Degradation Effect

Abstract The effects of thermally and Fe(II) activated potassium persulfate (PPS) on sludge dewatering performance were compared systematacially. Sludge dewaterability was monitored by measuring capillary suction time (CST) and sludge specific resistance to filtration (SRF), and the degradation effect was characterized by Chemical oxygen demand (COD), total organic carbon (TOC), ammonia nitrogen (NH4+-N) and extracellular polymeric substances (EPS). The Change of extracellular polymer substance (EPS) including soluble, loosely bound and tightly bound EPS (S-EPS, LB-EPS and TB-EPS) with time and PPS dosage was monitored to discuss the oxidation efficiency of thermally and Fe(II) activated PPS. Sludge supernate were analyzed by three dimensional fluorescence excitation-emission spectrum (3D-EEM) to confirm the proteins transformation. The result showed that sludge dewaterability in terms of CST and SRF were enhanced with increasing PPS dosage and condition time of both two activated methods. While Fe(II) activated PPS could reduce sludge CST and SRF to preferred values at low PPS dosage and short condition time. Maenwhile, sludge degradation effect was also more obvious. Mechanically, sludge TB-EPS in proteins and polysaccharides converted to SB-EPS was more quickly with Fe(II) activated PPS. Besides, thermally activated PPS tended to oxidize the protein in the supernatant first.

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Enhancing the sludge dewaterability by electrolysis/electrocoagulation combined with zero-valent iron activated persulfate process

Chemical Engineering Journal ◽

10.1016/j.cej.2016.06.041 ◽

2016 ◽

Vol 303 ◽

pp. 636-645 ◽

Cited By ~ 117

Author(s):

Yifu Li ◽

Xingzhong Yuan ◽

Zhibin Wu ◽

Hou Wang ◽

Zhihua Xiao ◽

...

Keyword(s):

Zero Valent Iron ◽

Sludge Dewaterability ◽

Activated Persulfate

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Extracellular polymeric substances and bound water drastically affect bioleached sludge dewaterability at low temperature

Environmental Technology ◽

10.1080/09593330.2014.911755 ◽

2014 ◽

Vol 35 (20) ◽

pp. 2538-2545 ◽

Cited By ~ 6

Author(s):

Yongwei Song ◽

Guanyu Zheng ◽

Minbo Huo ◽

Bowen Zhao ◽

Lixiang Zhou

Keyword(s):

Low Temperature ◽

Extracellular Polymeric Substances ◽

Bound Water ◽

Sludge Dewaterability

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Variations of sludge characteristics during the advanced anaerobic digestion process and the dewaterability of the treated sludge conditioning with PFS, PDMDAAC and synthesized PFS-PDMDAAC

Water Science & Technology ◽

10.2166/wst.2018.387 ◽

2018 ◽

Vol 78 (5) ◽

pp. 1189-1198 ◽

Cited By ~ 1

Author(s):

Jinghui Zhang ◽

Hong Yang ◽

Wei Li ◽

Yang Wen ◽

Xingmin Fu ◽

...

Keyword(s):

Particle Size ◽

Anaerobic Digestion ◽

Extracellular Polymeric Substances ◽

Three Dimensional ◽

Sludge Treatment ◽

Capillary Suction ◽

Excitation Emission Matrix ◽

Digestion Process ◽

Sludge Dewaterability ◽

Polyferric Sulfate

Abstract Anaerobic digestion with thermal hydrolysis pretreatment (THP), also called advanced anaerobic digestion (AAD), is a mainstream technology for sludge treatment. AAD changes sludge, it can degrade extracellular polymeric substances (EPS), release EPS from the sludge, and alter the particle size distribution. We synthesized PFS–PDMDAAC from the inorganic coagulant polyferric sulfate (PFS) and the organic coagulant polymer polydimethyldiallylammonium chloride (PDMDAAC) in various PFS:PDMDAAC weight ratios. We investigated the effects of PFS–PDMDAAC pretreatment on AAD sludge dewaterability, and developed an explanation for them. Capillary suction time (CST) was used as a measure of sludge dewaterability. Dissolved organic matter, the three-dimensional excitation emission matrix, particle size (d0.5), zeta potential, and sludge microstructure were observed in order to explain changes in sludge dewaterability that resulted from different compositions and dosages of coagulants. Treatment with PFS alone gave no significant improvement in sludge dewaterability. PDMDAAC used alone greatly improved sludge dewaterability. Synthesized PFS–PDMDAAC which had a relatively high proportion of PDMDAAC by weight performed similarly to PDMDAAC. PFS–PDMDAAC synthesized in the ratio (PDF:PDMDAAC) 1:5 by weight provided good dewaterability. The dosage can be reduced by 16.7% of the dosage for conditioning by PDMDAAC alone.

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