In this review, the use of MESe are evaluated in the monitoring of volatile fatty acids (VFAs) during the anaerobic digestion of high strength wastewater, with a focus on slaughterhouse wastewater. VFAs are identified as a key intermediary in anaerobic digestion, hence their accumulation could be used to infer possible process instability of anaerobic digesters. Current sample measurement for VFAs through off-line laboratory analysis can be costly, time consuming, and require specialist skills. Consequently, microbial electrochemical sensors (MESe) are currently being investigated as a low-cost alternative method for in-line VFA measurement. In this paper, the fundamental operation of MESe is summarised, including the exploration of several factors that would impact the operation of MESe in real wastewater applications. It is found that, in the context of wastewater sensing, MESe technology has been unable to bridge the gap between the laboratory and real-world anaerobic digesters effectively. Important issues surrounding biofouling, sensitivity, and detection range are explored and prioritised in this review, and an overview of potential research pathways is provided. These include the potential to further explore alternate electrode materials, use of ion exchange membranes, and development of other sensor components, as further described in the review.
Keywords: Abattoir wastewater; Anaerobic digestion; Bioelectrochemical systems; Microbial electrochemical technologies; Sensors; Volatile fatty acids.
Copyright © 2020 Elsevier B.V. All rights reserved.