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

The performance of a new one-phase reactor, called NITRAMMOX (R), 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 (R) 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 (R) 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 (q(max)) 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 (R) reactor showed good performance and robustness treating wastewater with low COD/N, with stability to substrate loading shocks.

Automated summary

The study evaluated the performance of a new single-phase reactor fed with increasing nitrogen loading rates from swine wastewater, showing stable operation and high nitrogen removal efficiency even under high nitrogen loading rates. The reactor demonstrated good performance and robustness treating wastewater with low COD/N, with stability to substrate loading shocks.