A quantitative method to evaluate microbial electrolysis cell effectiveness for energy recovery and wastewater treatment

Type
Article

Authors
Ivanov, Ivan
Ren, Lijiao
Siegert, Michael
Logan, Bruce E.

KAUST Grant Number
KUS-I1-003-13

Date
2013-10

Abstract
Microbial electrolysis cells (MECs) are potential candidates for sustainable wastewater treatment as they allow for recovery of the energy input by producing valuable chemicals such as hydrogen gas. Evaluating the effectiveness of MEC treatment for different wastewaters requires new approaches to quantify performance, and the establishment of specific procedures and parameters to characterize the outcome of fed-batch treatability tests. It is shown here that Coulombic efficiency can be used to directly calculate energy consumption relative to wastewater treatment in terms of COD removal, and that the average current, not maximum current, is a better metric to evaluate the rate of the bioelectrochemical reactions. The utility of these methods was demonstrated using simulated current profiles and actual wastewater tests. Industrial and domestic wastewaters were evaluated using small volume MECs, and different inoculation strategies. The energy needed for treatment was 2.17kWhkgCOD-1 for industrial wastewater and 2.59kWhkgCOD-1 for domestic wastewater. When these wastewaters were combined in equal amounts, the energy required was reduced to 0.63kWhkgCOD-1. Acclimation of the MEC to domestic wastewater, prior to tests with industrial wastewaters, was the easiest and most direct method to optimize MEC performance for industrial wastewater treatment. A pre-acclimated MEC accomplished the same removal (1847 ± 53 mg L-1) as reactor acclimated to only the industrial wastewater (1839 ± 57 mg L-1), but treatment was achieved in significantly less time (70 h versus 238 h). © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Citation
Ivanov I, Ren L, Siegert M, Logan BE (2013) A quantitative method to evaluate microbial electrolysis cell effectiveness for energy recovery and wastewater treatment. International Journal of Hydrogen Energy 38: 13135–13142. Available: http://dx.doi.org/10.1016/j.ijhydene.2013.07.123.

Acknowledgements
The authors would like to thank Air Products and Chemicals, Inc. (APCI) for providing the industrial wastewater samples. This research has been supported by APCI and Award KUS-I1-003-13 from the King Abdullah University of Science and Technology (KAUST).

Publisher
Elsevier BV

Journal
International Journal of Hydrogen Energy

DOI
10.1016/j.ijhydene.2013.07.123

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