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

2014 ◽  
Vol 35 (20) ◽  
pp. 2538-2545 ◽  
Author(s):  
Yongwei Song ◽  
Guanyu Zheng ◽  
Minbo Huo ◽  
Bowen Zhao ◽  
Lixiang Zhou
Keyword(s):  
Low Temperature ◽  
Extracellular Polymeric Substances ◽  
Bound Water ◽  
Sludge Dewaterability

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.

Capillary suction time (CST) as a measure of sludge dewaterability

1996 ◽  
Vol 34 (3-4) ◽  
pp. 443-448 ◽  
Author(s):  
G. W. Chen ◽  
W. W. Lin ◽  
D. J. Lee
Keyword(s):  
Water Content ◽  
Specific Resistance ◽  
Bound Water ◽  
The Other ◽  
Solid Concentration ◽  
Capillary Suction ◽  
Good Index ◽  
Other Hand ◽  
Sludge Dewaterability ◽  
Bound Water Content

The feasibility of employment of capillary suction time (CST) for characterizing the dewaterability of excess activated sludges was examined. The CST was shown as a good index for sludge filterability, if only the product of solid concentration and average specific resistance is of interest. On the other hand, the bound water content cannot be directly evaluated from the CST data.

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 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.

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