A mechanistic model for electrochemical nutrient recovery systems

Thompson Brewster, Emma, Mehta, Chirag M., Radjenovic, Jelena and Batstone, Damien J. (2016) A mechanistic model for electrochemical nutrient recovery systems. Water Research, 94 176-186. doi:10.1016/j.watres.2016.02.032

Author Thompson Brewster, Emma
Mehta, Chirag M.
Radjenovic, Jelena
Batstone, Damien J.
Title A mechanistic model for electrochemical nutrient recovery systems
Journal name Water Research   Check publisher's open access policy
ISSN 1879-2448
Publication date 2016-05-01
Year available 2016
Sub-type Article (original research)
DOI 10.1016/j.watres.2016.02.032
Open Access Status Not Open Access
Volume 94
Start page 176
End page 186
Total pages 11
Place of publication London, United Kingdom
Publisher IWA Publishing
Collection year 2017
Language eng
Formatted abstract
Electrochemical membrane technologies such as electrodialysis have been identified as key technologies to enable nutrient recovery from wastewater. However, current electrochemical models are focused on simpler solutions than wastewater and omit key outputs such as pH, or total cell potential. A combined physico-chemical and electrochemical model was developed which includes the mechanisms of competitive transport of ions, implicit inclusion of H+ and OH, pH (including ionic activity and ion pairing), different factors contributing to total cell potential and a novel method for ion exchange membrane transport. The model outputs compare well with measurements from experiments and simulate secondary effects such as electrode reactions and current leakage. Results found that membrane, rather than boundary layer or bulk resistance was the major contributor to potential drop, and that apparent boundary layers were relatively thick (3 ± 1 mm). Non-ideal solution effects such as ion-pairing and ionic activity had a major impact, particularly on multi-valent Ca2+ ions, which enhances the capability of electrodialysis to recover monovalent nutrient ions such as K+ and NH4+. Decreased resistivity of ion exchange membranes to specific ions (for example, in this case nitrate) could also be detected. The methods here are validated using a comparatively simple synthetic solution of five ionic components, but are able to be easily scaled for a more complex solution, and are also compatible with additional mechanisms such as precipitation, fouling, and scaling.
Keyword Electrodialysis
Nutrient recovery
Electrochemical modelling
Physico-chemical modelling
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
Advanced Water Management Centre Publications
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