Electro-bioremediation of nitrate and arsenite polluted groundwater

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 m3Net 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−3Net 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.

Additional Info

  • Year: 2021
  • Authors: Ceballos-Escalera A., Pous N., Chiluiza-Ramos P., Korth B., Harnisch F., Bañeras L., Balaguer M.D., Puig S.
  • Reference: Water Research, Open Access, Volume 19015, February 2021, Article number 116748

Search articles




Laboratory of Chemical and Enviromental Engineering

Institut de Medi Ambient
Universitat de Girona
Campus Montilivi
17003 Girona

Parc Científic i Tecnològic de la UdG
Edifici Jaume Casademont, Porta B
Pic de Peguera, 15
17003 Girona
Tel. +34 972 41 98 59




Social Media

Follow us on ...

Facebook Twitter Youtube Linkedin

NOTE! This site uses cookies and similar technologies. If you not change browser settings, you agree to it. Cookie Policy