Zeolite powder based polyurethane sponges as biocarriers in moving bed biofilm reactor for improving nitrogen removal of municipal wastewater

This study aims to enhance nitrogen removal efficiency of amoving bed biofilm reactor (MBBR) by developing a new MBBR with zeolite powder-based polyurethane sponges as biocarriers (Z-MBBR). Results indicated the total nitrogen (TN) removal efficiency and simultaneous nitrification and denitrification (SND) performance in Z-MBBR were nearly 10% higher than those in the conventional MBBR with sponges as biocarriers (S-MBBR). About 84.2 +/- 4.8% of TN was removed in Z-MBBR compared to 75.1 +/- 6.8% in S-MBBR. Correspondingly, the SND performance in Z-MBBR and S-MBBR was 90.7 +/- 4.1% and 81.7 +/- 6.5%, respectively. The amount of biofilm attached to new biocarriers (0.470 +/- 0.131 g/g carrier) was 1.3 times more than that of sponge carriers (0.355 +/- 0.099 g/g carrier). Based on the microelectrode measurements and microbial community analysis, more denitrifying bacteria existed in the Z-MBBR system, and this can improve the SND performance. Consequently, this new Z-MBBR can be a promising option for a hybrid treatment system to better nitrogen removal from wastewater. (C) 2018 Elsevier B.V. All rights reserved.