| Title |
Combining electro-bioremediation of nitrate in saline groundwater with concomitant chlorine production |
| ID_Doc |
21956 |
| Authors |
Puggioni, G; Milia, S; Dessì, E; Unali, V; Pous, N; Balaguer, MD; Puig, S; Carucci, A |
| Title |
Combining electro-bioremediation of nitrate in saline groundwater with concomitant chlorine production |
| Year |
2021 |
| Published |
|
| Abstract |
Groundwater pollution and salinization have increased steadily over the years. As the balance between water demand and availability has reached a critical level in many world regions, a sustainable approach for the management (including recovery) of saline water resources has become essential. A 3-compartment cell configuration was tested for a new application based on the simultaneous denitrification and desalination of nitrate-contaminated saline groundwater and the recovery of value-added chemicals. The cells were initially operated in potentiostatic mode to promote autotrophic denitrification at the bio-cathode, and then switched to galvanostatic mode to improve the desalination of groundwater in the central compartment. The average nitrate removal rate achieved was 39 +/- 1 mgNO3- -N L-1 d-1, and no intermediates (i.e., nitrite and nitrous oxide) were observed in the effluent. Groundwater salinity was considerably reduced (average chloride removal was 63 +/- 5%). Within a circular economy approach, part of the removed chloride was recovered in the anodic compartment and converted into chlorine, which reached a concentration of 26.8 +/- 3.4 mgCl2 L-1. The accumulated chlorine represents a value-added product, which could also be dosed for disinfection in water treatment plants. With this cell configuration, WHO and European legislation threshold limits for nitrate (11.3 mgNO3- -N L-1) and salinity (2.5 mS cm-1) in drinking water were met, with low specific power consumptions (0.13 +/- 0.01 kWh g- 1NO3- -Nremoved). These results are promising and pave the ground for successfully developing a sustainable technology to tackle an urgent environmental issue. |
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