A single-stage MABR reactor in the post-treatment of poultry slaughterhouse wastewater: nitrogen removal and microbial community

The deammonification process is an efficient alternative to remove nitrogen from wastewater with a low carbon/nitrogen ratio. However, the reactor configuration and operational factors pose challenges for applications in treatment systems to remove nitrogen from municipal and industrial wastewater on a large scale. To address this gap, this study evaluated a new deammonification strategy using a single-stage membrane aerated biofilm reactor (MABR), operated with continuous flow, under different hydraulic retention times (HRT) in the post-treatment of poultry slaughterhouse wastewater with a low nitrogen load, similar to domestic wastewater. The performance of the MABR reactor and the microbial community was evaluated over a long period at HRTs of 12, 24, and 36 hours, corresponding to nitrogen volumetric loads of 181.0 g N.m^-3.d^-1, 87.4 g N.m^-3.d^-1 and 67.8 g N.m^-3.d^-1. The results show that total nitrogen (TN) removal and the microbial community in the MABR reactor were influenced by changes in HRT. The highest efficiency in TN removal was obtained with an HRT of 24 hours, in which the maximum TN removal efficiency was 77.04%. Candidatus Brocadia and Candidatus Jettenia were the two genera of bacteria with Anammox activity present in the reactor, with relative abundances of 7.27% and 0.74%, respectively. This study helps to deepen the understanding of the application of the single-stage MABR reactor in real wastewater treatment with a low nitrogen load.