Characteristic identification of extracellular polymeric substances and sludge flocs affected by microalgae in microalgal-bacteria aggregates treating wastewater

2021 ◽  
Vol 44 ◽  
pp. 102418
Author(s):  
Cong-Cong Tang ◽  
Rong Wang ◽  
Tian-Yang Wang ◽  
Zhang-Wei He ◽  
Yu Tian ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Sludge Flocs

Characteristics of different fractions of microbial flocs and their role in membrane fouling

2011 ◽  
Vol 63 (2) ◽  
pp. 262-269 ◽  
Author(s):  
H. J. Lin ◽  
W. J. Gao ◽  
K. T. Leung ◽  
B. Q. Liao
Keyword(s):  
Microbial Community ◽  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Sludge Flocs ◽  
Microbial Flocs ◽  
Thermomechanical Pulping ◽  
Gradient Gel Electrophoresis ◽  
Sludge Cake ◽  
The Difference

Characteristics of different fractions (small flocs vs. large flocs) of sludge flocs from a submerged anaerobic membrane bioreactor treating thermomechanical pulping (TMP) whitewater were determined using various analytic techniques, including extraction and chemical analysis of extracellular polymeric substances (EPS), particle size analyzer, and polymer chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). The results showed that the fraction of smaller flocs contained a higher level of bound EPS and had a higher fractal dimension as compared to the fraction of larger flocs. PCR-DGGE analysis indicated that there were significant differences in microbial community between the fraction of smaller flocs and large flocs. The microbial community of the smaller flocs was similar to that of the sludge cake layers, indicating the pioneering role of the microbial community in smaller flocs in membrane fouling. These findings provide a new insight in the difference of membrane fouling potential between smaller flocs and larger flocs fraction.

scholarly journals Improvement of phosphorus release from sludge by combined electrochemical-EDTA treatment

2021 ◽  
Vol 83 (8) ◽  
pp. 1824-1833
Author(s):  
Yunfeng Xu ◽  
Fanglu Hu ◽  
Xin Wang ◽  
Yangwei Qu ◽  
Lu Xu ◽  
...  
Keyword(s):  
Metal Ions ◽  
Extracellular Polymeric Substances ◽  
Ethylenediaminetetraacetic Acid ◽  
Organic Phosphorus ◽  
Electrochemical Treatment ◽  
Phosphorus Release ◽  
Dissolved Phosphorus ◽  
Sludge Flocs ◽  
Edta Treatment ◽  
Reactive Phosphorus

Abstract In this paper, combined with the addition of ethylenediaminetetraacetic acid (EDTA), the electrochemical treatment of waste activated sludge (WAS) was investigated to explore its effect on the release of phosphorus (P) from WAS. The results showed that during the electrochemical treatment, the addition of EDTA could significantly promote the release of P from the WAS to the supernatant, the optimal amount of EDTA was 0.4 g/g total suspended solids (TSS), when the release of total dissolved phosphorus (TDP), organic phosphorus (OP) and molybdate reactive phosphorus (PO43−-P) were 187.30, 173.84 and 13.46 mg/L, respectively. OP was the most likely form of P to be released during this process. Moreover, combined electrochemical-EDTA treatment could promote the release of P and metal ions from extracellular polymeric substances (EPSs) to the supernatant, and increase the solubility and disintegration of sludge. EDTA chelated the metal ions of sludge flocs and phosphate precipitates to cause sludge floc decomposition, thereby promoting the release of P from WAS.

scholarly journals Improvements on activated sludge settling and flocculation using biomass-based fly ash as activator

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaoqian Chen ◽  
Fangong Kong ◽  
Yingjuan Fu ◽  
Chuanling Si ◽  
Pedram Fatehi
Keyword(s):  
Fly Ash ◽  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Sem Analysis ◽  
Sludge Flocs ◽  
Before And After ◽  
Number Of Microorganisms ◽  
Adverse Influence ◽  
Settling Performance ◽  
Sludge Settling

Abstract Biomass-based fly ash and wastewater are undesired products of the pulping industry. Recently, the use of biomass-based fly ash as an adsorbent (i.e., a valued material) for constituents of wastewater effluents was reported. In this work, the settling performance and properties of activated sludge were studied in the presence of fly ash. Upon mixing, fly ash increased the zeta potential of the sludge from −31 mV to −28 mV, which was due to the release of cationic ions from fly ash in the sludge suspension. The sludge settling and its flocculation affinity were improved through the complexation of flocs and released cation ions from fly ash. The relationships between the protein/polysaccharide (PN/PS) ratio and the content of extracellular polymeric substances (EPS) as well as the ratio and the properties of the sludge flocs were determined. A correlation between the total loosely bound-EPS (LB-EPS) content and the effluent suspended solids (ESS) (Pearson’s coefficient, rp = 0.83) was observed. The performance of sludge flocculation and settling were much more closely correlated with LB-EPS than with tightly bound EPS (TB-EPS). Scanning electron microscopy (SEM) analysis of sludge flocs before and after EPS extraction showed that the sludge flocs contained a large number of microorganisms, mainly Bacillus and Cocci. The amount of LB-EPS had an adverse influence on bioflocculation, effluent clarification and sludge settling affinity. The sludge properties had a moderate relationship with the PN/PS ratio of LB-EPS. Also, no correlation could be established between the ratio and the TB-EPS content.

scholarly journals Evaluation of hydrophobically associating cationic starch-based flocculants in sludge dewatering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pan Hu ◽  
Shaohang Shen ◽  
Hu Yang
Keyword(s):  
Extracellular Polymeric Substances ◽  
Synergistic Effects ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Structural Factors ◽  
Cationic Starch ◽  
Sludge Dewatering ◽  
Sludge Flocs ◽  
Structure Activity ◽  
Sludge Dewaterability

AbstractTwo series of binary graft cationic starch-based flocculants (CS-DMCs and CS-DMLs) with different hydrophilicity and charge density (CD) were prepared by graft copolymerization of acrylamide with 2-(Methacryloyloxy)-N,N,N-trimethylethanaminium chloride and methacrylic acid 2-(benzyldimethylaminio) ethyl chloride, respectively, on the starch (St) backbone. The sludge dewatering performance of CS-DMCs and CS-DMLs were evaluated and compared based on the changes in filter cake moisture content (FCMC), specific resistance of filtration (SRF), fractions and components of extracellular polymeric substances, and various physiochemical characteristics of sludge flocs and cakes. Increase in CD of the St-based flocculants caused improved sludge dewaterability. Under the similar CD, CS-DML with relatively high hydrophobicity exhibited lower FCMC and SRF, larger and denser sludge flocs, and better permeability of sludge cakes than CS-DMCs due to the synergistic effects of charge neutralization, bridging flocculation and hydrophobic association. Furthermore, a second-order polynomial model on the basis of phenomenological theory was successfully applied to quantitatively evaluate the influences of the two important structural factors of these St-based flocculants, i.e., hydrophobicity and CD, on the sludge dewaterability. The structure–activity relationship of the St-based flocculants in sludge dewatering was obtained according to the theoretic simulation. The dewatering mechanisms was discussed in depth on the basis of the experimental and simulated results; besides, the FCMC and optimal dose can be predicted by the established structure–activity relationship. This current work offered a novel and valuable way to exploit and design of low-cost and high-performance graft natural polymeric flocculants applied in efficient conditioning of sludge.

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