Performance and microbial features of Anammox in a single-phase reactor under progressive nitrogen loading rates for wastewater treatment plants

Abstract

The performance of a new one-phase reactor, called NITRAMMOX®, fed with increasing nitrogen loading rates (NLR) from swine wastewater was evaluated. The aim of the present study was to investigate the stability of Partial Nitritation/Anammox (PN/A) process in a new single-phase reactor under 500 mg NH3-N L−1 (2.04 ± 0.30 g N L−1 d−1). NITRAMMOX® reactor was operated under progressive nitrogen loading rates, and sludge samples were collected and analyzed for microorganism community, extracellular polymeric substance (EPS) and protein/polysaccharides ratio (PN/PS) evaluation at each experimental phase. The NITRAMMOX® reactor can be operated until a nitrogen loading rate of 2 g N L−1 d−1, with nitrogen removal efficiency higher than 80%. On these conditions, no inhibitions by substrate or nitrite were achieved, and the specific ammonia consumption rate (qmax) did not decrease (35.49 mg NH3-N gVSS−1 h−1). The main bacteria at the phylum and genus level had shifted according to high-throughput Miseq sequencing analyses. Candidatus Brocadia became the dominant Anammox genus under high-nitrogen loading rate (32.55%), which correlated positively with TN removal efficiency, EPS, protein/polysaccharide (PN/PS) and specific bacteria activity, respectively. NITRAMMOX® reactor showed good performance and robustness treating wastewater with low COD/N, with stability to substrate loading shocks.