A new Sponge-GAC-Sponge membrane module for submerged membrane bioreactor use in hospital wastewater treatment

A new Sponge-GAC-Sponge membrane module design for use in a membrane bioreactor (SGSMBR) is presented in this study. This work highlights an alternative MBR design in which a composite Sponge-Granular Activated Carbon-Sponge (SGS) layer is covered around the membrane module. The performance and membrane fouling of both the SGSMBR and a University of Cape Town with membrane (UCT-MBR) system are investigated for use in hospital wastewater treatment. It has been found that decreasing the hydraulic retention time (HRT) from 8 to 4 h resulted in higher COD, NH3, and P removal efficiency in the SGSMBR process when compared with the UCT-MBR process. Membrane fouling is controlled in the SGSMBR by decreasing the cake layer thickness on the membrane surface by about 96%. The flux recovery efficiency (FRE%) of the membranes was highly improved in the new SGSMBR design. The COD, NH3, and P removal efficiency was improved significantly from 73.6, 84.9, and 58% by using UCT-MBR to 85, 96, and 71%, respectively by using UCT-SGSMBR and SGSMBR. Finally, the SGSMBR showed biomass retention superior to that measured in the UCT-MBR This work reveals, for the first time, that a composite layer covering the membrane module is a viable alternative to anoxic and anaerobic conditions in MBR systems. (C) 2018 Elsevier B.V. All rights reserved.