Bioelectrochemical systems (BES) have proven their capability to treat nitrate-contaminated saline groundwater and simultaneously recover value-added chemicals (such as disinfection products) within a circular economy-based approach. In this study, the effect of the hydraulic retention time (HRT) on nitrate and salinity removal, as well as on free chlorine production, was investigated in a 3-compartment BES working in galvanostatic mode with the perspective of process intensification and future scale-up. Reducing the HRT from 30.1 +/- 2.3 to 2.4 +/- 0.2 h led to a corresponding increase in nitrate removal rates (from 17 +/- 1 up to 131 +/- 1 mgNO3--N L-1d-1), although a progressive decrease in desalination efficiency (from 77 +/- 13 to 12 +/- 2 %) was observed. Nitrate concentration and salinity close to threshold limits indicated by the World Health Organization for drinking water, as well as significant chlorine production were achieved with an HRT of 4.9 +/- 0.4 h. At such HRT, specific energy consumption was low (6.8 center dot 10-2 +/- 0.3 center dot 10-2 kWh g-1NO3--Nremoved), considering that the supplied energy supports three processes simultaneously. A logarithmic equation correlated well with nitrate removal rates at the applied HRTs and may be used to predict BES behaviour with different HRTs. The bacterial community of the bio-cathode under galvanostatic mode was dominated by a few populations, including the genera Rhizobium, Bosea, Fontibacter and Gordonia. The results provide useful information for the scale-up of BES treating multi-contaminated groundwater.

Effect of hydraulic retention time on the electro-bioremediation of nitrate in saline groundwater

Giulia Puggioni;Stefano Milia;Valentina Unali;Riccardo Ardu;Elena Tamburini;Alessandra Carucci;
2022-01-01

Abstract

Bioelectrochemical systems (BES) have proven their capability to treat nitrate-contaminated saline groundwater and simultaneously recover value-added chemicals (such as disinfection products) within a circular economy-based approach. In this study, the effect of the hydraulic retention time (HRT) on nitrate and salinity removal, as well as on free chlorine production, was investigated in a 3-compartment BES working in galvanostatic mode with the perspective of process intensification and future scale-up. Reducing the HRT from 30.1 +/- 2.3 to 2.4 +/- 0.2 h led to a corresponding increase in nitrate removal rates (from 17 +/- 1 up to 131 +/- 1 mgNO3--N L-1d-1), although a progressive decrease in desalination efficiency (from 77 +/- 13 to 12 +/- 2 %) was observed. Nitrate concentration and salinity close to threshold limits indicated by the World Health Organization for drinking water, as well as significant chlorine production were achieved with an HRT of 4.9 +/- 0.4 h. At such HRT, specific energy consumption was low (6.8 center dot 10-2 +/- 0.3 center dot 10-2 kWh g-1NO3--Nremoved), considering that the supplied energy supports three processes simultaneously. A logarithmic equation correlated well with nitrate removal rates at the applied HRTs and may be used to predict BES behaviour with different HRTs. The bacterial community of the bio-cathode under galvanostatic mode was dominated by a few populations, including the genera Rhizobium, Bosea, Fontibacter and Gordonia. The results provide useful information for the scale-up of BES treating multi-contaminated groundwater.
Circular economy; Denitrification; Microbial electrochemical technology; Saline groundwater; Value-added products; Water recovery; Biodegradation, Environmental; Bioreactors; Chlorine; Nitrates; Nitrogen Oxides; Groundwater; Water Pollutants, Chemical
File in questo prodotto:
File Dimensione Formato  
STOTEN-D-22-08067_pre_referaggio.pdf

accesso aperto

Descrizione: pre-print (cioè pre-referaggio)
Tipologia: versione pre-print
Dimensione 4.62 MB
Formato Adobe PDF
4.62 MB Adobe PDF Visualizza/Apri
2022_Puggioni_preproof.pdf

Solo gestori archivio

Tipologia: versione post-print
Dimensione 1.77 MB
Formato Adobe PDF
1.77 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/345174
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact