Impact of gas injection on physicochemical properties of waste activated sludge: A linear relationship between the change of viscoelastic properties and the change of other physiochemical properties

Bobade, V, Evans, G, Baudez, J and Eshtiaghi, N 2018, 'Impact of gas injection on physicochemical properties of waste activated sludge: A linear relationship between the change of viscoelastic properties and the change of other physiochemical properties', Water Research, vol. 144, pp. 246-253.


Document type: Journal Article
Collection: Journal Articles

Title Impact of gas injection on physicochemical properties of waste activated sludge: A linear relationship between the change of viscoelastic properties and the change of other physiochemical properties
Author(s) Bobade, V
Evans, G
Baudez, J
Eshtiaghi, N
Year 2018
Journal name Water Research
Volume number 144
Start page 246
End page 253
Total pages 8
Publisher Elsevier
Abstract Aeration process in the waste activated sludge treatment accounts for 75% of total energy consumption of the treatment plant. The main purpose of the aeration process is to enhance the biodegradation of the liquid waste. Gas bubbles, rising through the liquid, improves mixing, reduces inhomogeneities in the treatment tank and enhances biological reactions. Thus aeration intensity and several physicochemical properties of feed such as viscosity, total suspended solids, and surface charge play a significant role in the biological reaction. This paper examines the impact of the gas injection rate on some physicochemical properties of waste activated sludge namely rheological properties, suspended solids, soluble COD (sCOD), surface tension, and zeta potential. The impact of four different gas flow rates on four different concentrations of waste activated sludge properties was analysed. The results showed that in linear viscoelastic regime the viscous and elastic modulus decreases linearly with an increase in gas flow rate. The amount of stress imposed by gas injection also showed a direct relationship with gas velocity. Gas injection also showed a substantial impact on soluble COD, suspended solids, and zeta potential. Additionally, a linear relationship was observed between the percentage change in the above mentioned physical properties and stress imposed by gas injection. These results confirm that gas injection produces additional shear impacting sludge physicochemical properties and therefore changes its rheological behaviour. The extra stress induced by gas injection can be predicted using a simple model based on sludge concentration and gas velocity.
Subject Rheology
Wastewater Treatment Processes
Keyword(s) Waste activated sludge
Viscoelastic properties
Suspended solids
Soluble COD
Zeta potential
DOI - identifier 10.1016/j.watres.2018.07.041
Copyright notice © 2018 Elsevier Ltd. All rights reserved.
ISSN 0043-1354
Additional Notes Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
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