Reductive potential from cathode electrode as an option for the achievement of short-cut nitrification in bioelectrochemical systems

Abstract

Nitrogen removal based on short-cut nitrification (SCN) have attract more attentions, in which stable nitrite accumulation is prerequisite. In this study, different reductive potential was applied to inhibit nitrite oxidizing bacteria for achievement of SCN in aerobic cathode chamber of bioelectrochemical systems with dissolved oxygen concentration of 3.5 mg/L. The results demonstrated that the applied potential facilitated nitrite accumulation with high ammonia oxidation rates. The maximum nitrate accumulation rate of 87.61% was obtained at -800 mV. The abundance of Nitrosomonas and Thauera increased while Nitrospira abundance declined with more negative reductive potentials. The activity of nitric oxide reductase was also evidently inhibited. The above-mentioned three genera were the keystone taxa in co-occurrence network with high degree and closeness centrality. Interestingly, total nitrogen (TN) removal was enhanced simultaneously in the absence of external organic carbon. Reductive potential would be a promising approach for achieving SCN and simultaneously TN removal.

Key findings

• ▸Short-cut nitrification was achieved in bioelectrochemical systems using cathode electrode reductive potential.
• ▸The reductive potential of the cathode electrode was found to be a key factor in promoting short-cut nitrification.
• ▸The study demonstrated the potential of bioelectrochemical systems to reduce nitrate levels in wastewater.

Keywords

Identifiers

DOI

10.1016/j.biortech.2021.125553

PubMed

34280852

Journal

Bioresource Technology

Year

2021