The current economy is based on a linear model with the pattern of “take–make–consume and dispose”. Industrial processes that use membrane technology are not an exception of the current economy model and membranes tend to be discarded when the flow rate/water quality is unrecoverable. In desalination, the annual membrane replacement percentage is around 10–20%. This, together with the continuous growth of reverse osmosis technology, is creating a non-stop accumulation of end-of-life reverse osmosis membranes.
Generally, end-of-life membranes are handled according to the laws of each country usually ending up in landfills. Landfill disposing is wasteful, environmentally damaging and costly. Furthermore, it is in direct conflict with EU goals to move towards a circular economy system and to achieve a cross continental recycling society.
TRANSFOMEM aimed to increase sustainability of membrane-based water treatment processes, by improving membrane durability and reducing the environmental costs associated to this technology. This was achieved through an environmentally-friendly membrane recycling process, where end-of life Reverse Osmosis (RO) membranes from desalination plants are transformed and implemented as Ultrafiltration (UF) and Nanofiltration (NF) membranes.
At laboratory scale membranes were recycled using the pasive methodology. Results obtained were replicable at pilot scale.
The pasive and active recycling methods were evaluated at pilot scale. In both cases, the methodologies are replicable obtaining similar results when tranforming different membranes. When comparing both methodologies (see figure below) results show that both methodologies are robust obtaining similar process performance of the recycled membranes in terms of rejection coefficients and permeability.
The implementation of recycled UF and NF membranes were validated in three different applications:
- Brackish water desalination using recycled NF membranes. The validation was conducted in the desalination plant of Cuevas del Almanzora, Almería, Spain.
- Pre-treatment process before reverse osmosis step in desalination using recycled UF membrane. The validation was conducted in the desalination plant of Muchamiel, Alicante, Spain.
- Urban wastewater tertiary treatment. The validation was conducted in the wastewater treatment plant of Guadalajara, Spain.
You can read here the LAYMAN'S REPORT of the LIFE Transfomem project.
TRANSFOMEM "Transformation of disposed reverse osmosis membranes into recycled ultra-and nanofiltration membranes" was a European Community co-funding LIFE project with contract number LIFE13 ENV/ES/000751.
Project's implementors: IMDEA Water Institute (Coordinating beneficiary), SADYT and VALORIZA AGUA.