Article published on 13 August 2019
Biomass Membrane Contactor is an advanced membrane contactor panel that will enable the optimization of diffusion based bio-processes as it solves specific shortcomings of existing conventional and novel reverse membrane reactor systems.
In conventional submerged membrane bioreactors (MBRs), membranes are immersed in the biomass suspension. Fermentation broth or treated wastewater is removed in an out-to-in direction and collected in the membrane lumen through suction while the biomass is retained in the bioreactor/fermentor. In contrast, in the VITO Biomass Membrane Contactor (BMC) reverse membrane bioreactors (rMBR) cells or biomasses are entrapped between two membrane layers, thus separating them from the actual feed medium. In such rMBR system the membranes can be integrated in sachets, columns or other membrane encasements.
rMBRs – as opposed to MBR – have some advantages as the separation is driven by differences in concentration and not by pressure. Cells (or biomass) is also kept separate from the feed medium in rMBR. rMBR can be considered a contactor, as it enables a diffusion based process. But the design needs to guarantee low-fouling & optimal control of circulation.
The BMC solves some issues that diffusion-based classical MBRs and rMBR are confronted with, thanks to its advanced design and improved circulation system/flow management, both for gases and fluids. This allows for improved mass transfer. The BMC is a single piece membrane element/panel/module comprising two well-anchored membrane layers, and an internal spacing structure (multi-wall sheet). This internal space is divided into segments, which enable a cross-flow in a controlled and homogeneous way at the internal sides of the membrane layers. This in addition to the cross-flow at the outside of the two membrane layers. The membrane contactor has areas that are used for suspension/fluid passage only, and neighbouring areas that enable the exchange of molecules between the internal and external spaces of the two membrane layers. The orientation of the segments on the inside of the BMC can be directed horizontally or vertically during operation. The internal circulation of the cell suspension/liquids can run either through a fluid pump only, or through internal recirculation of the gas/bio gas from the gas layer/head space above the liquid level in the segments to assist the flow.
Encapsulation of biomass inside membrane panel
Diffusion driven (non-pressure driven) transport (of solutes between outer and inner membrane section)
Optimised flow control at inner and outer membrane area for maximal diffusional exchange
Internal structure that reduces risk of clogging because it allows easy recirculation of biomass
Controlled conditions for biomass recirculation to avoid membrane fouling or biofilm formation which would reduce the membrane surface area for exchange
Possibility to recirculate gas for fouling control
Possibility to control biomass content
Optimized flow & control (of ingoing and outgoing fluids and gases) of biomass
Avoiding fouling and undesired build up of gases and cells
Avoiding suboptimal process efficiency
Fermentation of complex feeds containing high concentrations of inhibitory compounds
Fermentation of feeds containing a variety of sugar sources
Fermentation of feeds or bioconversion of waste streams with high suspended solid content
Industrial batch/semi batch and continuous fermentation of e.g. beer, ethanol
2-in-1 fermentations with exchange of metabolites (e.g. production bacteriocins, antibiotics, nutrients, etc or other products with symbiotic effects)
Controlled cocultures: good control of hydraulic and operational conditions for each process independently possible;
Biomass contactor applications
Liquid-liquid, gas-liquid, … contactor set-ups
Rapid bio gas production
Production of fine chemicals, viruses, monoclonal antibodies, etc
About the author
Research & Development expert with extensive expertise in membrane filtration in a wide range of industrial applications. Specific focus on the potential and applicability of porous and dense ceramic membranes. Co-inventor of different membrane-based chemical processes for process intensification, and innovative functionalisation of ceramic membranes for affinity-based separations.