Performance of a laboratory-scale moving bed biofilm reactor (MBBR) and its microbial diversity in palm oil mill effluent (POME) treatment.

• An alternative palm oil mill effluent treatment was developed using a laboratory-scale MBBR. • Two types of supporting media in the MBBR system were compared. • Increasing the MFF and HRT improved the MBBR treatment of palm oil mill effluent. • More than 10 species of bacteria were found on the supporting media of the MBBR system. The treatment performance of palm oil mill effluent (POME) using a laboratory-scale moving bed biofilm reactor (MBBR) was investigated in this study. Two types of biofilm carriers were used to fill the MBBR: black plastic media (BPM) and Hexafilter (HEX). Three media filling fractions (MFFs: 25 %, 50 % and 70 %) and retention times (RTs: 24, 48 and 72 h) were investigated to achieve the best MBBR performance in terms of the removal of chemical oxygen demand (COD) and ammonia-nitrogen (NH 3 -N) from POME. Increasing the RT significantly improved the removal of COD and NH 3 -N, whereas increasing the MFF resulted in insignificant changes. Overall, HEX performed better than BPM at 50 % MFF (72 h RT). Metagenomics analysis identified approximately 13 phyla of bacteria on the HEX compared to the BPM with only 10 phyla. Based on these findings, the laboratory-scale MBBR deserved a vote as an alternative treatment for POME under appropriate RTs and MFFs and in the presence of a suitable microbial community. [ABSTRACT FROM AUTHOR]