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Oxygen supply management to intensify wastewater treatment by a microbial electrochemical snorkel

Hoareau, Morgane and Etcheverry, Luc and Erable, Benjamin and Bergel, Alain Oxygen supply management to intensify wastewater treatment by a microbial electrochemical snorkel. (2021) Electrochimica Acta, 394. ISSN 0013-4686

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Official URL: https://doi.org/10.1016/j.electacta.2021.139103

Abstract

The microbial electrochemical snorkel (MES) is a low-cost, low-maintenance technology that could considerably reduce wastewater treatment costs by reducing the need for aeration. An MES is a single electrode. The lower part, in the anoxic zone of the bioreactor, oxidizes organic matter by transferring electrons to the electrode. The upper part, in the oxic zone, releases the electrons by reducing dissolved oxygen. This study gives new insights into the correlation between the MES potential, the concentration of dissolved oxygen and COD abatement, thus enabling practical rules to be extracted for running the MES in optimal conditions, particularly for adjusting the aeration zone and frequency. Here, aeration promoted the cathodic reaction and increased the MES potential to a maximum (0.0 to 0.1 V/SCE). After aeration stopped, the potential dropped to a minimum (< -0.4 V/SCE). With 26 cm high MESs, sequential aeration at the top was not sufficient to support an effective cathodic zone, while aeration at the bottom was detrimental to the formation of the microbial anode. With MESs 48 cm high and aeration set up in the highest quarter, 30 minutes of aeration every 4.5 hours gave potential variations that were stable for weeks. The MESs continued to oxidize organic matter 30 minutes after the aeration had stopped. In this period, the MESs removed 3 to 6.3 times more COD than the control reactors. Increasing the electrode capacitance is therefore suggested as an effective way to further decrease the aeration cost by decreasing the aeration frequency.

Item Type:Article
HAL Id:hal-03338569
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse 1 Capitole - UT1 (FRANCE)
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Deposited On:08 Sep 2021 15:35

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