Innovative encapsulated self-forming dynamic bio-membrane bioreactor (ESFDMBR) for efficient wastewater treatment and fouling control

Abstract

The concept of a novel living encapsulated self-forming dynamic bio-membranes (ESFDM) for an innovative wastewater treatment in membrane bioreactor (MBR) is presented in the current study. The active filtering membrane is encapsulated, and thus stabilized, between two support meshes with pore in micrometer size. The combination of activated sludge, the ESFDM and the cake layer formed external to the filtering module contributed to the treatment of municipal wastewater. COD concentration reductions (average value of 95.55 ± 1.44%) by ESFDM bioreactor (ESFDMBR) were comparable to those obtained with a previously reported membrane bioreactor (MBR), where a conventional membrane was studied under the same operating conditions. The ESFDMBR, compared to the conventional MBR, obtained higher reductions of NH3-N, NO3–N and PO43–P concentrations. Increased removals of nitrogen-containing nutrients were ascribed to anoxic conditions reached in the ESFDM layer protected from the aeration by the external cake layer. Rate of increase of transmembrane pressure (TMP) per day in the ESFDMBR (0.03 kPa/day) was lower than the value obtained in the previously reported conventional MBR (8.08 kPa/day). Lower concentrations of fouling precursors in combination with the effective filtration capacity of the porous living ESFDM resulted in the reduction of the fouling rate. Analysis of microbiological community revealed that the microbial community structures in the mixed liquor and ESFDM were different. The ESFDM layer promoted growth of bacteria as indicated by the higher total cell count and higher microbial diversity compared to those observed in the mixed liquor.