Photocatalytic bright membrane textile for filtration and reuse of urban wastewaters: an answer to membrane fouling in tertiary treatment – LumiMem

The originalities of the LumiMem project state at several levels:

-Design and control a new membrane filtration technology to obtain a very good quality of filtered water while reducing the environmental impact of the operation (energy and emissions).
-Use new techniques for the manufacture of mixed-matrix polymer hollow fibres.
-To understand and model the mechanisms involved in the development of new hollow fibres
-integrating the problem of the sustainability of technology by studying the ageing of the new membrane material and comparing its environmental impact compared to conventional cleaning.

The ability to generate results within the framework of the LUMIMEM project is supported by a consortium of academic and industrial actors with recognised, multidisciplinary and complementary skills: IEM Montpellier (Elaboration and implementation of Membranes, photocatalysis processes, microbiological analyses); LGC Toulouse (ageing of the membranes); Polymem, 31 (manufacturer of hollow fibre membranes); Brochier Technologies, 69 (manufacturer of optic fibres fabrics, photocatalysis expertise).

The research project concerns the treatment of water with a new membrane process. It has significant societal and economic impacts, water management being part of global societal issues. Tertiary treatment in sewage treatment plants allows, through the recycling of effluents, to decrease the pressure on water resources and are therefore part of the sustainable management programmes of this resource. In particular, the design of new membrane materials to limit fouling will ensure access of a high number of people to quality water while reducing the cost of membrane filtration.

The LUMIMEM project started in february 2018, so it involved no publication at this time.

Membrane processes know for several years a remarkable growth in the treatment of wastewaters because they are able to deal with water quality and flow fluctuations that conventional activated sludge processes can’t process. Their development remains nevertheless hampered by problems of membrane fouling, which have a negative impact both financial (related to clean-up costs) and environmental (related to the energy cost and chemicals used). Previous works to remove this lock focused on the optimization of operating conditions or configurations of membrane modules, but none of these alternatives has proved to be completely satisfying. Face of the disadvantages of these traditional solutions, the development of low-fouling and self-cleaning membranes would be a major paradigm shift.

In this context, the LumiMem project addresses the problem of fouling in a very original way, through the development of a self-cleaning bright membrane textile, hollow fiber (HF) TiO2 polymer membranes with optic fibers (OF) equipped with LEDs UVA. This configuration will enable the in-situ irradiation of TiO2 nanoparticles during membrane filtration. The (super-)hydrophilic character of TiO2 would allow improving the flow water and limitation of the fouling while its photocatalytic and/or disinfectant activity by combination with UVA respectively would induce the degradation of organic matter fouling and a reduction in the development of biofilm on the surface of the membrane.

The original goals of the LumiMem project state at several levels:
-Design and mastering a new technology of membrane photofiltration, involving the new membrane textile material, to get a treated water of high quality while reducing the environmental impact of the operation (energy and emissions).
-Use of new techniques (co-extrusion) to develop polymer hollow fiber containing nanoparticles of TiO2.
-Understand and model the mechanisms involved during the developement of the new hollow fiber PVDF-TiO2.
-Integrate the issue of sustainability of the technology by studying the ageing of the new membrane textile and comparing its environmental impact compared to the conventional ways of cleaning/cleaning.

This new approach of development of TiO2-PVDF membranes and their association with optical fibers generates several scientific risks which have been evaluated and taken into account in the project LumiMem. However, the potential of the project states on preliminary work performed in IEM, having established the proof of concept for the "reference" case of flat-sheet membranes PVDF/TiO2 and having shown, for optimum conditions of development and under UV irradiation, the limitation of membrane fouling and their self-cleaning behavior.

The ability to generate results in the LumiMem project is also supported by a consortium that includes academic and industrial actors with recognized, multidisciplinary and complementary skills: IEM Montpellier (development and implementation of membranes, photocatalysis, microbiological processes); LGC Toulouse (ageing of the membranes); Polymem Toulouse (the manufacturer of hollow fiber membranes); Brochier Technologies Villeurbanne (the manufacturer of optic fibers, expertise photocatalysis fabrics).