Integrating bioelectrochemical system with aerobic bioreactor for organics removal and caustic recovery from alkaline saline wastewater

Tharanga N. Weerasinghe Mohottige; Maneesha P. Ginige; Anna H. Kaksonen; Ranjan Sarukkalige; Ka Yu Cheng

doi:10.1016/j.jenvman.2023.117422

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Integrating bioelectrochemical system with aerobic bioreactor for organics removal and caustic recovery from alkaline saline wastewater

Journal article

Open access

Peer reviewed

Integrating bioelectrochemical system with aerobic bioreactor for organics removal and caustic recovery from alkaline saline wastewater

Tharanga N. Weerasinghe Mohottige, Maneesha P. Ginige, Anna H. Kaksonen, Ranjan Sarukkalige and Ka Yu Cheng

Journal of environmental management, Vol.334, 117422

2023

DOI: https://doi.org/10.1016/j.jenvman.2023.117422

PMID: 36801680

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Abstract

Environmental Sciences

Environmental Sciences & Ecology

Life Sciences & Biomedicine

Science & Technology

Bioelectrochemical systems (BES) are increasingly being explored as an auxiliary unit process to enhance con-ventional waste treatment processes. This study proposed and validated the application of a dual-chamber bioelectrochemical cell as an add-on unit for an aerobic bioreactor to facilitate reagent-free pH-correction, or-ganics removal and caustic recovery from an alkaline and saline wastewater. The process was continuously fed (hydraulic retention time (HRT) of 6 h) with a saline (25 g NaCl/L) and alkaline (pH 13) influent containing oxalate (25 mM) and acetate (25 mM) as the target organic impurities present in alumina refinery wastewater. Results suggested that the BES concurrently removed the majority of the influent organics and reduced the pH to a suitable range (9-9.5) for the aerobic bioreactor to further remove the residual organics. Compared to the aerobic bioreactor, the BES enabled a faster removal of oxalate (242 +/- 27 vs. 100 +/- 9.5 mg/L.h), whereas similar removal rates (93 +/- 16 vs. 114 +/- 23 mg/L.h, respectively) were recorded for acetate. Increasing catholyte HRT from 6 to 24 h increased the caustic strength from 0.22% to 0.86%. The BES enabled caustic production at an electrical energy demand of 0.47 kWh/kg-caustic, which is a fraction (22%) of the electrical energy requirement for caustic production using conventional chlor-alkali processes. The proposed application of BES holds promise to improve environmental sustainability of industries in managing organic impurities in alkaline and saline waste streams.

Details

Title: Integrating bioelectrochemical system with aerobic bioreactor for organics removal and caustic recovery from alkaline saline wastewater
Authors/Creators: Tharanga N. Weerasinghe Mohottige - Curtin University
Maneesha P. Ginige - Commonwealth Scientific and Industrial Research Organisation
Anna H. Kaksonen - Commonwealth Scientific and Industrial Research Organisation
Ranjan Sarukkalige - Curtin University
Ka Yu Cheng - CSIRO Land and Water
Publication Details: Journal of environmental management, Vol.334, 117422
Publisher: Elsevier
Number of pages: 8
Grant note: CSIRO Mineral Resources CSIRO Environment Curtin University
Identifiers: 991005598269807891
Copyright: © 2023 The Authors.
Murdoch Affiliation: School of Engineering and Energy
Language: English
Resource Type: Journal article

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Collaboration types: Domestic collaboration
Citation topics: 7 Engineering & Materials Science; 7.229 Mineral & Metal Processing; 7.229.2385 Red Mud Valorization
Web Of Science research areas: Environmental Sciences
ESI research areas: Environment/Ecology