Temperature effect on shear flow and thixotropic behavior of residual sludge from wastewater treatment plant

Hammadi, Larbi; Ponton, Alain; Belhadri, Mansour

doi:10.1007/s11043-012-9191-z

Cited by 15 publications

(10 citation statements)

References 16 publications

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“…Thus, the small structures were less pseudoplastic than the larger structures because the small structures were less deformable. The simultaneous decrease of the consistency index and increase of the power law index with increased temperature has been observed by other authors [31,32]. The reduction in the sludge viscosity after the application of thermal energy (Fig.…”

Section: Resultssupporting

confidence: 75%

Structural model to study the influence of thermal treatment on the thixotropic behaviour of waste activated sludge

Ruiz-Hernando

Labanda

Llorens

2015

Chemical Engineering Journal

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Section: Resultssupporting

confidence: 75%

Structural model to study the influence of thermal treatment on the thixotropic behaviour of waste activated sludge

Ruiz-Hernando

Labanda

Llorens

2015

Chemical Engineering Journal

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“…A recent new area of consideration relates to the anaerobic digestion of organic waste and municipal wastewater in processes such as ammonia stripping from digestate to reduce toxicity [4], and carbon dioxide (CO 2 ) enrichment of sewage sludge or food waste for enhanced biogas production and carbon uptake [5]. For instance, sewage sludge is considered a fluid of complex matrix exhibiting pseudoplastic rheological behaviour [6,7], with its apparent viscosity (µ a ) being highly affected by temperature [8], solid content [9][10][11] or shear history [12].…”

Section: Introductionmentioning

confidence: 99%

Gas to liquid mass transfer in rheologically complex fluids

Fernández

Cartmell

Soares

et al. 2015

Chemical Engineering Journal

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International audienceThe increase of studies relaying on gas to liquid mass transfer in digested sludge (shear thinning fluid) necessitates a better understanding of the impact of apparent viscosity (μa) and rheology in process performance. Mass transfer retardation due to μa variations was investigated in a pilot scale absorption bubble column for Newtonian and shear thinning fluids with varied superficial gas velocities (UG). A non-linear reduction of mass transfer efficiency with increasing μa was observed, being the impact higher at low μa ranges and high UG. An increase of 114 cPo in μ from 1.01 to 115 cPo in glycerol solutions saturated with UG = 1.73 cm s−1 led to a reduction of 96% in kLa (α = 0.04), while a comparable raise from 115 to 229 cPo implied a reduction of 52% (α = 0.02). Slug–annular flow regime was identified for shear thinning fluids of high μa (1.0% and 1.5% carboxymethyl cellulose sodium salt solutions), where bubble buoyancy was conditioned by the μ of the fluid at rest and the active volume for mass transfer was reduced because of the presence of stagnant areas. Conditions imitating the rheological variability of anaerobically digested sewage sludge were included within those tested, being a reduction in gas transfer efficiency of 6 percentage points (from 7.6 ± 0.3% to 1.6 ± 0.1%) recorded when increasing μa from 130 to 340 cPo. It is thus recommended that rheology and μa variability are accounted for within the design of gas to liquid mass transfer systems involving digested sewage sludge, in order to avoid reductions in process performance and active volum

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“…To determine the gelling time (gel point), next to oscillation rheology, we also used the flow measurement (correlation of shear stress to changing shear rates), which is used to analyse the flow rheological properties of complete polymer solutions [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…The changes of G elasticity (energy storage) modulus and G viscosity (energy loss) modulus are determined by the dependence of a small amplitude oscillatory shear as a function of cross-linking time at specified angular frequency (ω). At the beginning of the reaction, the G modulus is larger than G , at the gel point G = G and G is much larger than G after the completion of the gelation [9][10][11]18]. …”

Section: Introductionmentioning

confidence: 99%

Rheology of Cross-Linked Poly(Sodium Acrylate)/Sodium Silicate Hydrogels

et al. 2015

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Transparent hydrogels consisting of poly(sodium acrylate) and sodium silicate were synthesized by freeradical polymerization of sodium acrylate (ANa) in an aqueous solution of sodium silicate (i.e. water glass) with the silicate modulus (M) 2.50 and the Midafen R-102 polymer filler, in the presence of sodium thiosulphate/potassium persulphate (NTS/KPS) as the redox initiators and N , Nmethylenebisacrylamide as the cross-linking monomer. The hydrogels, obtained in this way, were rheologically tested, and also the gelling point, dependence of shear stress on shear rate, and oscillation constants were determined. The results indicated that during the cross-linking reaction, which is associated with a gradual building of the three-dimensional gel structure, the reaction mixture changes its rheological behaviour from pseudo-thixotropic at the beginning of the reaction to pseudo-anti-thixotropic in the end. Both elasticity modulus G and viscosity modulus G during the reaction and for the cast samples after 24 h have practically the same values and the phase shift angle δ is below 20 • which means that we obtained a highly elastic material. It was also found that the elasticity modulus G values increase with the content of sodium silicate in the sample.B Joanna Mastalska-Popławska

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Temperature effect on shear flow and thixotropic behavior of residual sludge from wastewater treatment plant

Cited by 15 publications

References 16 publications

Structural model to study the influence of thermal treatment on the thixotropic behaviour of waste activated sludge

Structural model to study the influence of thermal treatment on the thixotropic behaviour of waste activated sludge

Gas to liquid mass transfer in rheologically complex fluids

Rheology of Cross-Linked Poly(Sodium Acrylate)/Sodium Silicate Hydrogels

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