Comparison between a moving bed bioreactor and a fixed bed bioreactor for biological phosphate removal and denitrification

Moving bed bioreactors (MBBR) and fixed bed bioreactors (FBBR) were compared for biological phosphorus removal and denitrification. The sorption denitrification P-elimination (S-DN-P) process was selected for this study. Results indicated that all nutrients were removed by the FBBR process compared with the MBBR process: 19.8% (total COD), 35.5% (filtered COD), 27.6% (BOD₅), 62.2% (acetate), 78.5% (PO₄-P), and 54.2% (NO₃-N) in MBBR; 49.7% (total COD), 54.0% (filtered COD), 63.2% (BOD₅), 99.6% (acetate), 98.6% (PO₄-P), and 75.9% (NO₃-N) in FBBR. The phosphate uptake and NO₃-N decomposition in the FBBR process during the denitrification phase were much higher than for the MBBR process despite being of shorter duration. Results obtained from this study are helpful in elucidating the practical implications of using MBBR and FBBR for the removal of bio-P and denitrification from wastewater.