Rheological behaviors of anaerobic granular sludge in a spiral symmetry stream anaerobic bioreactor

2015 ◽  
Vol 72 (4) ◽  
pp. 658-664 ◽  
Author(s):  
Xiaoguang Chen ◽  
Ruobin Dai ◽  
Xinyi Xiang ◽  
Chengyu Ma ◽  
Gang Li ◽  
...  
Keyword(s):  
Apparent Viscosity ◽  
Granular Sludge ◽  
Shear Thinning ◽  
Anaerobic Granular Sludge ◽  
Anaerobic Bioreactor ◽  
Rheological Behaviors ◽  
Viscosity Behavior ◽  
Thixotropic Behavior ◽  
The Relationship ◽  
Sludge Concentration

The rheological behaviors of the anaerobic granular sludge (AGS) in a spiral symmetry stream anaerobic bioreactor (SSSAB) were investigated. Shear-thinning behavior, thixotropic behavior, concentration–viscosity behavior and temperature–viscosity behavior were evaluated based on the constitutive equation of the AGS. The results indicated that the Herschel–Bulkley model was able to adequately describe the constitutive relation of AGS in the SSSAB. The AGS also showed shear-thinning behavior as well as thixotropic behavior. The critical shear rate and network strength of the AGS were 61.8 s−1 and 497.0 W m−3, respectively. The relationship between the apparent viscosity and the sludge concentration was illustrated and explained by the Woodcock formula. The relationship between apparent viscosity of the AGS and temperature could be modeled using the Arrhenius equation. The AGS was significantly thermo-sensitive and its mean energy of activation was 14.640 kJ mol−1. Notably, it was necessary to consider such behaviors in the hydrodynamic modeling of SSSAB in which shear condition, sludge concentration and temperature were in non-uniform distribution.

Formaldehyde toxicity in anaerobic systems

2000 ◽  
Vol 42 (5-6) ◽  
pp. 223-229 ◽  
Author(s):  
G. Gonzalez-Gil ◽  
R. Kleerebezem ◽  
G. Lettinga
Keyword(s):  
Granular Sludge ◽  
Anaerobic Granular Sludge ◽  
Formaldehyde Concentration ◽  
Trophic Groups ◽  
Toxicity Studies ◽  
Acetoclastic Methanogenesis ◽  
Dual Character ◽  
Formaldehyde Toxicity ◽  
Sludge Concentration

Formaldehyde toxicity during acetoclastic methanogenesis exerted a dual character: It was in part reversible and in part irreversible. Toxicity was only reversible at very low formaldehyde concentration. The degree of irreversible toxicity was proportionally related to the initial sludge concentration, but was independent of the initial specific acetoclastic activity. Formaldehyde conversion seemed to be dependent on the concentration of the various trophic groups present in the anaerobic granular sludge used. Hence biomass diversity may play an important role in the outcome of toxicity studies and may furthermore contribute to the explanation of the controversies with respect to toxicity values reported in literature.

Toxicity of Sulfite and Cadmium to Anaerobic Granular Sludge

1994 ◽  
Vol 29 (4) ◽  
pp. 581-598
Author(s):  
C.F. Shew ◽  
N. Kosaric
Keyword(s):  
Granular Sludge ◽  
Upflow Anaerobic Sludge Blanket ◽  
Shock Load ◽  
Anaerobic Sludge ◽  
Anaerobic Granular Sludge ◽  
Scanning Electron Micrographs ◽  
Bacterial Growth Rate ◽  
Digestion Rate ◽  
Sulfate Reducing ◽  
Load Conditions

Abstract Toxicity of sulfite (Na2SO3) and cadmium (CdCl2) ions to anaerobic granular sludge was investigated in 1.2 litre bench-scale upflow anaerobic sludge blanket (UASB) reactors during process acclimation and shock load conditions. Minimal sulfite toxicity was observed under gradual and shock load conditions at sulfite concentrations of up to 1000 mg S/L if proper acclimation was allowed to occur. No long-term toxic effects were observed although the COD digestion rate was temporarily inhibited by shock load of sulfite. Scanning electron micrographs indicated that more sulfate-reducing bacteria were present in the granules developed in the reactors with sulfite supplement although rod-shaped Methanosaeta-like bacteria were still dominant. High bacterial growth rate was observed in the reactors which were supplied with the feed containing sulfite. The COD digestion rate was inhibited at a cadmium loading rate of 2.4 g Cd per day under both acclimation and shock load conditions. Acclimation did not seem to improve the bacteria to tolerate the toxicity of cadmium. The concentration of free cadmium was very low in the reactors under normal conditions, but increased rapidly when the COD digestion in the reactors ceased. The bacteria could not be reactivated after inhibited by cadmium. When reactors were operated at low specific COD loading rates, more inorganic precipitates were formed inside the granules which consequently settled faster.

The High Pressure Rheology of Mixtures

2004 ◽  
Vol 126 (4) ◽  
pp. 697-702 ◽  
Author(s):  
Scott Bair
Keyword(s):  
Molecular Weight ◽  
High Pressure ◽  
Binary Systems ◽  
Viscosity Coefficient ◽  
Shear Thinning ◽  
Newtonian Viscosity ◽  
Double Shear ◽  
Ideal Mixing ◽  
Viscosity Behavior ◽  
Single Flow

The Newtonian mixing rules for several binary systems have been experimentally investigated. Some systems show non-ideal mixing response and for some systems the non-ideal response is pressure-dependent, yielding an opportunity for manipulation of the pressure-viscosity behavior to advantage. The mixing of differing molecular weight “straight cuts” can produce very different pressure-viscosity response. This behavior underscores the difficulty in predicting the pressure-viscosity coefficient based upon chemical structure and ambient viscosity since the molecular weight distribution is also important, but it also provides another opportunity to control the high-pressure response by blending. The first experimental observation of double shear-thinning within a single flow curve is reported. Blending then provides the capability of adjusting not only the Newtonian viscosity but also the non-Newtonian shear-thinning response as well.

scholarly journals Screening for electrical conductivity in anaerobic granular sludge from full-scale wastewater treatment reactors

2020 ◽  
Vol 159 ◽  
pp. 107575
Author(s):  
Leire Caizán-Juanarena ◽  
Annemiek ter Heijne ◽  
Jan Weijma ◽  
Doekle Yntema ◽  
Diego A. Suárez-Zuluaga ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Wastewater Treatment ◽  
Granular Sludge ◽  
Full Scale ◽  
Anaerobic Granular Sludge

Bioremediation of wastewaters with decabromodiphenyl ether by anaerobic granular sludge

2015 ◽  
Vol 128 ◽  
pp. 522-527 ◽  
Author(s):  
Shou-Qing Ni ◽  
Zhibin Wang ◽  
Lu Lv ◽  
Xueyou Liang ◽  
Longfei Ren ◽  
...  
Keyword(s):  
Granular Sludge ◽  
Anaerobic Granular Sludge ◽  
Decabromodiphenyl Ether
Sign in / Sign up

Export Citation Format

Share Document