Internal carbon source from sludge pretreated by microwave-H₂O₂ for nutrient removal in A²/O-membrane bioreactors

To improve the nutrient removal, the feasibility was studied for the organics released from sludge pretreated by microwave-H₂O₂ process (MHP) to be used as internal carbon source in two A²/O-membrane bioreactors (MBRs). The experiments were conducted for the nutrient removal and the membrane fouling. The results showed that the removal efficiencies of TN and TP were improved by 11% and 28.34%, respectively, as C/N ratio was adjusted to 8 by adding the internal carbon source, and the ratio of soluble chemical oxygen demand (sCOD) consumed easily for denitrification was about 46% of the total sCOD in the internal carbon source. The addition of the internal carbon sources did not lead to severe membrane fouling in the experimental A²/O-MBR. It is implied that the organics released from sludge pretreated by MHP could be used as the internal carbon source to enhance the nutrient removal in A²/O-MBRs.