Electro-bioremediation of nitrate and arsenite polluted groundwater

WATER RESEARCH

卷:190

Article

Ceballos-Escalera, Alba¹  Pous, Narcis¹  Chiluiza-Ramos, Paola²  Korth, Benjamin³  Harnisch, Falk³  Baneras, Lluis²  Balaguer, M. Dolors¹  Puig, Sebastia¹ 

[1] Univ Girona, Inst Environm, LEQUiA, C Maria Aurelia Capmany 69, E-17003 Girona, Spain

[2] Univ Girona, Inst Aquat Ecol, Grp Environm Microbial Ecol, C Maria Aurelia Capmany 40, E-17003 Girona, Spain

[3] Helmholtz Ctr Environm Res GmbH UFZ, Dept Environm Microbiol, Permoserstr 15, D-04318 Leipzig, Germany

关键词: Arsenic;    Denitrification;    Microbial electrochemical technology;    Bioelectrochemical system;    Continuous bioreactor;    Electroactive microorganism;   

DOI  :  10.1016/j.watres.2020.116748

来源: Elsevier

【 摘 要 】

The coexistence of different pollutants in groundwater is a common threat. Sustainable and resilient technologies are required for their treatment. The present study aims to evaluate microbial electrochemical technologies (METs) for treating groundwater contaminated with nitrate (NO3- ) while containing arsenic (in form of arsenite (As(III)) as a co-contaminant. The treatment was based on the combination of nitrate reduction to dinitrogen gas and arsenite oxidation to arsenate (exhibiting less toxicity, solubility, and mobility), which can be removed more easily in further post-treatment. We operated a bioelectrochemical reactor at continuous-flow mode with synthetic contaminated groundwater (33 mg N-NO3- L-1 and 5 mg As(III) L-1) identifying the key operational conditions. Different hydraulic retention times (HRT) were evaluated, reaching a maximum nitrate reduction rate of 519 g N-NO3- m(-3) (Net Cathodic Compartment )d(-1) at HRT of 2.3 h with a cathodic coulombic efficiency of around 100 %. Simultaneously, arsenic oxidation was complete at all HRT tested down to 1.6 h reaching an oxidation rate of up to 90 g As(III) m(-3) (Net Reactor Volume) d(-1) . Electrochemical and microbiological characterization of single granules suggested that arsenite at 5 mg L-1 did not have an inhibitory effect on a denitrifying biocathode mainly represented by Sideroxydans sp. Although the coexistence of abiotic and biotic arsenic oxidation pathways was shown to be likely, microbial arsenite oxidation linked to denitrification by Achromobacter sp. was the most probable pathway. This research paves the ground towards a real application for treating groundwater with widespread pollutants. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

Free