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

2016 ◽  
Vol 7 (2) ◽  
pp. 136-141 ◽  
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.

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

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.

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

2015 ◽  
Vol 72 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Lingling Hu ◽  
Yu Liao ◽  
Chun He ◽  
Wenqi Pan ◽  
Shangkun Liu ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Ph Value ◽  
Three Dimensional ◽  
Bound Water ◽  
Zero Valent Iron ◽  
Molar Ratio ◽  
Persulfate Oxidation ◽  
Potential Benefits ◽  
Sludge Dewaterability ◽  
Activated Persulfate

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.

scholarly journals 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

2018 ◽  
Vol 78 (5) ◽  
pp. 1189-1198 ◽  
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.

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

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.

scholarly journals The influence of different sludge concentrations on its dewaterability during bioleaching

2020 ◽  
Vol 81 (12) ◽  
pp. 2585-2598
Author(s):  
Wenfeng Yang ◽  
Liyuan Zeng ◽  
Weihao Zhang ◽  
Qiyong Yang ◽  
Tianfeng Wang ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Reduction Potential ◽  
High Efficiency ◽  
Specific Resistance ◽  
Principal Component ◽  
Buffering Capacity ◽  
Capillary Suction ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sludge Dewaterability

Abstract Bioleaching, a technologically and economically feasible technology, is considered as the high efficiency method to improve dewaterability in sewage sludge. The objective of this study was to investigate the effect of different sludge concentrations on bioleaching dewaterability and understand the mechanism of the effect of bioleaching on sludge dewaterability. Variation in pH, oxidation-reduction potential (ORP), capillary suction time (CST), specific resistance to filtration (SRF) and different fractions of extracellular polymeric substances (EPS) including slime EPS (S-EPS), loosely bound EPS (LB-EPS), and tightly bound EPS (TB-EPS) were determined. Different sludge concentrations (5, 10, 15, 20 and 30 g·L−1) were selected to investigate during bioleaching. Results indicated that sludge buffering capacity significantly inhibited bioleaching efficiency as sludge concentrations increased. Optimum enhancements in sludge dewaterability were observed during the 10 g·L−1 sludge concentration treatment, and reached a maximum when the pH was 2.11. The variation of different fractions of EPS revealed that the ratio of S-EPS/TB-EPS significantly affected sludge dewaterability. Principal component analysis and Pearson's correlation analysis both provided evidence that the higher TB-EPS followed by a very large reduction was positively correlated with sludge dewaterability. However, the increase of protein and DNA in S-EPS content was negatively correlated with sludge dewaterability.

scholarly journals Synergetic Effect of Combined CaO2 and Microwave Treatment on Waste Active Sludge Dewaterability and Organic Contaminants’ Removal

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Wang ◽  
Kankan Shang ◽  
Liangjun Da ◽  
Xingguo Liu ◽  
Yongjing Zhao ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Superoxide Anion ◽  
Extracellular Polymeric Substances ◽  
Synergetic Effect ◽  
Microwave Treatment ◽  
Sludge Dewatering ◽  
Active Sludge ◽  
Capillary Suction ◽  
Contaminants Removal ◽  
Sludge Dewaterability

This study investigated the synergetic effect of the combined calcium peroxide (CaO2) and microwave (MW) treatment on waste active sludge dewatering properties and organic contaminants’ removal. The optimal sludge dewaterability was obtained at CaO2 (20 mg/gVSS)/MW (70°C), and the capillary suction time decreased by 52% compared with raw sludge. Further investigation indicated that total extracellular polymeric substances (EPS), tightly bound EPS, total protein, and protein present in tightly bound EPS were closely correlated with sludge dewaterability. Tryptophan, aromatic protein–like substances and humic acid–like substances were the key compounds that affect sludge dewaterability. The charge neutralization and bridge effect of cation ions were strengthened when combined with MW irradiation. In addition, it was revealed that MW facilitated CaO2 to produce more hydroxyl and superoxide anion radicals. This study confirmed CaO2/MW to be an effective way to improve sludge dewatering and remove organic pollutants from sludge.

Enhancement of sewage sludge dewaterability by fungal conditioning with Penicillium simplicissimum NJ12: From bench- to pilot-scale consecutive multi-batch investigations

2021 ◽  
Author(s):  
Neng Tao ◽  
Xiu Wu ◽  
Feng Zhang ◽  
Zilei Pi ◽  
Jiaqi Wen ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Volume Fraction ◽  
Linear Regression Analysis ◽  
Pilot Scale ◽  
Recycling Rate ◽  
Penicillium Simplicissimum ◽  
Fungal Treatment ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Sludge Dewaterability

Abstract Bench- and pilot-scale successive multi-batch trials were conducted to investigate the performance and sustainability of fungal conditioning with Penicillium simplicissimum NJ12 for improving sludge dewatering. The dominant factors affecting the sludge dewaterability improvement by P. simplicissimum NJ12 were also identified. Fungal treatment with P. simplicissimum NJ12 at a volume fraction of 5% of the inoculum greatly improved the sludge dewaterability. This improvement was characterized by sharp decreases in the specific resistance to filtration from 1.97 × 1013 to 3.52 × 1011 m/kg and capillary suction time from 32 to 12 s within 3 days. Stepwise multiple linear regression analysis showed that a marked decrease (58.8%) in the protein content in slime extracellular polymeric substances and an increase in the zeta potential of the sludge (from − 35 to − 10 mV) were the most important factors that improved the dewaterability of sludge after fungal treatment. Consecutive processes of fungal treatment could be realized by recirculating the fungal-treated sludge with a recycling rate of 1:2 (Vbiotreated sludge/Vtotal sludge). The treatment effectiveness was maintained only over three successive cycles, but replenishment with fresh P. simplicissimum NJ12 would be provided periodically at set batch intervals. These findings demonstrate the possibility of P. simplicissimum NJ12-assisted fungal treatment for enhancing sludge dewatering.

Effect of using different proportions of inoculum during bioleaching on sludge dewaterability

2018 ◽  
Vol 2017 (3) ◽  
pp. 802-811 ◽  
Author(s):  
Qingfang Zhang ◽  
Wenfeng Yang ◽  
Qiyong Yang ◽  
Tianfeng Wang ◽  
Shenliang Chen ◽  
...  
Keyword(s):  
Crucial Role ◽  
Extracellular Polymeric Substances ◽  
Reduction Potential ◽  
Specific Resistance ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Geological Materials ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sludge Dewaterability

Abstract Bioleaching, the addition of bacteria to geological materials, has been applied to sludge to remove metals and improve upon sludge dewaterability. This paper investigates the effect of using different quantities of inoculum (bacteria) during bioleaching on sludge dewaterability. The analysis was based on bioleaching experiments conducted in a 20 L bio-reactor using different quantities of inoculum (20%, 10%, 5%, 2%, 0%). Changes in pH, oxidation reduction potential (ORP), capillary suction time (CST), specific resistance to filtration (SRF) and extracellular polymeric substances (EPS) were determined to gauge sludge dewatering. Results indicate that sludge dewaterability during the 2%, 10%, and 20% inoculum experiments declined through time. Decreased dewaterability is attributed to increases in the quantity of proteins and polysaccharides in slime EPS. Dewaterability improved during the 5% inoculum experiment, and reached a maximum when pH was 2.3. During this latter experiment, CST and SRF were reduced by 74% and 62%, respectively, in comparison to control conditions, while total EPS content decreased by 71%. The decrease in total EPS was primarily due to a decrease in proteins associated with tightly bound EPS (TB-EPS). Thus, changes in the amount of proteins in TB-EPS and sludge pH played a crucial role in sludge dewaterability.

Incorporation of spatial variability in modeling non-point source groundwater nitrate pollution

1996 ◽  
Vol 33 (4-5) ◽  
pp. 233-240 ◽  
Author(s):  
F. S. Goderya ◽  
M. F. Dahab ◽  
W. E. Woldt ◽  
I. Bogardi
Keyword(s):  
Spatial Variability ◽  
Point Source ◽  
Three Dimensional ◽  
Nitrate Contamination ◽  
Geostatistical Simulation ◽  
Chemical Measurements ◽  
Spatially Distributed ◽  
Potential Benefits ◽  
Zone Modeling ◽  
Physical And Chemical

A methodology for incorporation of spatial variability in modeling non-point source groundwater nitrate contamination is presented. The methodology combines geostatistical simulation and unsaturated zone modeling for estimating the amount of nitrate loading to groundwater. Three dimensional soil nitrogen variability and 2-dimensional crop yield variability are used in quantifying potential benefits of spatially distributed nitrogen input. This technique, in combination with physical and chemical measurements, is utilized as a means of illustrating how the spatial statistical properties of nitrate leaching can be obtained for different scenarios of fixed and variable rate nitrogen applications.

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