Dapelo, D 
ORCID: 0000-0002-3442-6857 and Bridgeman, J ORCID: 0000-0001-8348-5004
(2020)
A CFD strategy to retrofit an anaerobic digester to improve mixing performance in wastewater treatment.
WATER SCIENCE AND TECHNOLOGY, 81 (8).
pp. 1646-1657.
Abstract
To date, mixing design practice in anaerobic digestion has focussed on biogas production, but no adequate consideration has been given to energy efficiency. A coherent, comprehensive and generalized strategy based on computational fluid dynamics (CFD) modelling is proposed to improve mixing efficiency of a full-scale, unconfined gas-mixed digester for wastewater treatment. The model consists of an Euler-Lagrange (EL) model where biogas bubbles are modelled as the Eulerian dispersed phase, and non-Newtonian sludge as the Lagrangian continuous phase. Robustness tests show that mixing predictions are independent of bubble size. The CFD strategy comprises the assessment of different mixing geometries and a range of input gas flow rates. Quantitative results show that simple retrofitting measures are able to achieve a significant improvement in the degree of mixing with reduced mixing times, and consequently recommendations for best mixing geometry and gas flow rate are given. A generalization to a generic digester is discussed in a form that is readily usable by professionals and consultants.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | anaerobic digestion, CFD, mixing, multiphase, sludge, wastewater |
| Divisions: | Faculty of Science and Engineering > School of Engineering |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 13 Jun 2022 14:25 |
| Last Modified: | 18 Jan 2023 21:00 |
| DOI: | 10.2166/wst.2020.086 |
| Open Access URL: | https://iwaponline.com/wst/article/81/8/1646/72456... |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3156390 |
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