Nitrate electro-bioremediation and water disinfection for rural areas

Abstract

Nitrate-contaminated groundwater is a pressing issue in rural areas, where up to 40 % of the population lacks access to safely managed drinking water services. The high costs and complexity of centralised treatment in these regions exacerbate this problem. To address this challenge, the present study proposes electro-bioremediation as a more accessible decentralised alternative. Specifically, the main focus of this study is developing and evaluating a compact reactor designed to accomplish simultaneous nitrate removal and groundwater disinfection. Significantly, this study has established a new benchmark for nitrate reduction rate within bioelectrochemical reactors, achieving the maximum reported rate of 5.0 ± 0.3 kg NO3− m−3NCC d−1 at an HRTcat of 0.7 h. Furthermore, thein-situ generation of free chlorine was effective for water disinfection, resulting in a residual concentration of up to 4.4 ± 1.1 mg Cl2 L−1 in the effluent at the same HRTcat of 0.7 h. These achievements enabled the treated water to meet the drinking water standards for nitrogen compounds (nitrate, nitrite, and nitrous oxide) as well as pathogens content (T. coliforms, E. coli, and Enterococcus). In conclusion, this study demonstrates the potential of the electro-bioremediation of nitrate-contaminated groundwater as a decentralised water treatment system in rural areas with a competitive operational cost of 1.05 ± 0.16 € m−3

This work was funded through the European Union's Horizon 2020 project ELECTRA [no. 826244]. A.C-E. was supported by a PhD grant from the University of Girona (IF_UDG 2020). S.P. is a Serra Hunter Fellow (UdG-AG-575) and acknowledges the funding from the ICREA Academia award. LEQUIA has been recognised as a consolidated research group by the Catalan Government (2017-SGR-1552)

Open Access funding provided thanks to the CRUE-CSIC agreement with Elsevier

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