dc.contributor.author |
Hii, Kevin |
en |
dc.contributor.author |
Farno, Ehsan |
en |
dc.contributor.author |
Baroutian, Saeid |
en |
dc.contributor.author |
Parthasarathy, Rajarathinam |
en |
dc.contributor.author |
Eshtiaghi, Nicky |
en |
dc.date.accessioned |
2019-06-19T21:18:23Z |
en |
dc.date.issued |
2019-06 |
en |
dc.identifier.issn |
0043-1354 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/47238 |
en |
dc.description.abstract |
Rheological properties are important in the design and operation of sludge-handling process. Despite this, the rheology of sludge in thermal hydrolysis processes (TH) is not well described. In-situ measurements were performed to characterize the flow behaviour of various concentrations (7-13 wt%) of waste activated sludge (WAS) at TH conditions. Equations were presented for predicting in-situ rheological parameters (high-shear viscosity, η∞,i, consistency index, ki, and yield stress, σc,i) under various treatment conditions, which are useful for design of process units. The equations enable convenient estimation of in-situ properties based on ambient rheological measurements. Results suggested that the proportion of sludge solubilization and its rate were unaffected by varying sludge concentration. Thermally treated sludge still exhibited gel-like, viscoelastic characteristics similar to untreated sludge; however, the storage (G') and loss (G") moduli decreased with higher treatment temperatures. Frequency and creep responses were described by a fractional derivatives Kelvin-Voigt (FKV) model, which showed increasing viscous characteristics of treated sludge. These equations can be utilised in CFD models. Results obtained from oscillatory measurements can also approximate steady-shear behaviour by comparing dynamic viscosity, η'(ω), and steady-shear viscosity, η(γ̇), whose values were very similar. This enables convenient estimation of steady-shear behaviour of sludge from oscillatory measurements, which is found to be a non-destructive technique for measuring flow behaviour of highly concentrated sludge. Yield stress can also be predicted from the product of modified Cox-Merz shift factors and storage modulus (G'). Practical engineering implications of the rheological observations were discussed. |
en |
dc.format.medium |
Print-Electronic |
en |
dc.language |
eng |
en |
dc.relation.ispartofseries |
Water research |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.subject |
Rheology |
en |
dc.subject |
Sewage |
en |
dc.subject |
Hydrolysis |
en |
dc.subject |
Viscosity |
en |
dc.title |
Rheological characterization of thermal hydrolysed waste activated sludge. |
en |
dc.type |
Journal Article |
en |
dc.identifier.doi |
10.1016/j.watres.2019.03.039 |
en |
pubs.begin-page |
445 |
en |
pubs.volume |
156 |
en |
dc.rights.holder |
Copyright: The author |
en |
pubs.end-page |
455 |
en |
pubs.publication-status |
Published |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/RestrictedAccess |
en |
pubs.subtype |
Journal Article |
en |
pubs.elements-id |
769341 |
en |
pubs.org-id |
Engineering |
en |
pubs.org-id |
Chemical and Materials Eng |
en |
dc.identifier.eissn |
1879-2448 |
en |
pubs.record-created-at-source-date |
2019-04-07 |
en |
pubs.dimensions-id |
30953843 |
en |