BF-MBR: Pros and cons of the potential for new reactor deigns and operation

Coupling biofilm reactors with membrane processes as biofilm membrane bioreactors (BF-MBR) is an interesting development as an alternative technology to activated sludge membrane bioreactors (AS-MBR). Biofilm technology for wastewater treatment can provide substantially lower suspended solid environments for membrane filtration compared to activated sludge processes. Potential benefits are; reduced energy consumption for aeration systems (lower viscosity), less membrane clogging problems, lower fouling potentials, ease of membrane cleaning, and new membrane module designs (i.e. higher membrane packing densities). This study was aimed to propose and investigate alternative membrane reactor designs and process configurations of the BF-MBR process. Alternative and novel biofilm reactor designs have been investigated, for example; a double-deck aerated moving bed biofilm reactor, two-stage aerobic-anaerobic biofilm reactor. The performance and design of the biofilm reactors was aimed to determine TSS control, effluent quality, and enhanced membrane filterability. The biofilm effluent on average had low TSS (typically <50 mg/L), low turbidities and FCOD. Alternative membrane modules and membrane filtration unit designs have been investigated. These include flat sheet systems, tubular and capillary membranes supplied from various manufacturers.