Bioelectrochemical Nitrate Reduction in a Continuous Flow Microbial Electrolysis Cell

High Nitrate concentrations in groundwater present considerable public health hazards. This study examines a dual-chamber Microbial Electrolysis Cell (MEC) reactor, consisting of two cylindrical borosilicate glass chambers (cathode and anode), for nitrate reduction from synthetic groundwater, using enriched mixed cultures from Venice Lagoon sediments. Different cathodic potentials were tested, with -450 mV vs. SHE used during batch mode and -450 mV, -550 mV, and -750 mV vs. SHE potentials, with three different Hydraulic Retention Times of 0.63, 1.35, and 0.38 days, tested during continuous flow mode. The highest Denitrification Rate of 72.58 ± 19.28 mgL−1d−1 was achieved at -750 mV vs. SHE with a low HRT of 0.38 day. Comparisons between biotic and abiotic conditions at -750 mV vs. SHE and 0.63 day HRT showed slightly higher rates in biotic environments (59.01 ± 9.88 mgL−1d−1 vs. 45.41 ± 1.17mgL−1d−1 ). The study highlights the potential of MEC technology for efficient nitrate reduction in groundwater.