Marine anammox bacteria-driven nitrogen removal from saline wastewater under different vanadium (v) doses: Evaluation on performance and kinetics

Abstract

This study used a sequencing batch reactor to investigate the nitrogen removal performance of marine anammox bacteria (MAB) from nitrogen-rich saline wastewater with addition of a transition element, vanadium (V(V)). The findings showed that the performance of nitrogen removal by MAB was enhanced by dosing proper amount of V (V) (i.e. 0.25–20 mg/L), but the effectiveness deteriorated at higher doses (>20 mg/L). Vanadium (V) level at 1 mg/L was found to be an optimal dose for complete removal of ammonia (NH4+-N) within only 160 min. Substrate conversion rates were improved and stayed at high for longer periods with lower vanadium doses (0.25–10 mg/L), which indicates that the MAB-mediated anammox reaction rate was accelerated by adding V(V). Moreover, V(V) was more preferential than partial nitrite (NO2−) to be used as the electron acceptor by MAB, thus the new marine anammox process is termed as Vammox. Kinetic analysis using remodified Logistic model, modified Boltzman and Gompertz models on the nitrogen removal processes in typical operational conditions with V(V) addition revealed that none of the three models was appropriate at higher V(V) doses (>20 mg/L). Nevertheless, the remodified Logistic model was most suitable at lower V(V) doses (≤20 mg/L).