Recently, membrane technology group form IMDEA Water has published a Review in Desalination Journal about the possible strategies to follow in order to approach the membranes technoly field to a circular economy model. To this end, this review analyses the life cycle of reverse osmosis (RO) membranes, from preventing membrane fouling to membrane management when it become a waste.

Recently, membrane technology group form Imdea Water has published a Review in Desalination about the possible strategies to follow in order to approach the membranes technoly field to a circular economy model. To this end, this review analizes the life cycle of reverse osmosis (RO) membranes, from preventing membrane fouling to membrane management when it become a waste.

Desalination of sea and brackish water by reverse osmosis is broadly implemented and established in the industry. Energy consumption and membrane fouling represent some of the major concerns in membrane technology because they increase the costs associated with treated water.

In this way, the review summarizes the most representative research activities conducted to prevent membrane fouling, focusing mainly in two issues. On the one hand, there are several studies about preparing new membranes or on the modification of surfaces using different techniques to make them more resistant to fouling.. On the other hand, pretreatment and highly efficient cleaning protocols have been developed in order to prolong the membrane lifespan as much as possible. As described in the review, these improvements extend the life of the membranes but still is inevitable becoming waste.

Therefore, once the RO membranes cease to be effective in the process since its discharge and its separation capacity decrease or because they require increased operating pressure, are discarded by desalination plants. The life of these membranes ranges from 5 to 10 years depending on water quality and operating conditions, and therefore have a significant annual replacement rate (around 15%). Consequently, as a result, there is a non-stop accumulation of end-of-life reverse osmosis membranes in landfills. Consequently, industrial processes that use membrane technology follow a lineal model economy: from a resource, a product is manufactured, it is consumed and discarded, regardless of the environmental consequences.

Unfortunately, scarce research has been detected in literature regarding the management of membranes at the end of their life. For this reason, the research group has tried to take a further step and the review summarizes the alternative routes for reuse and recycling membranes that have been discarded by desalination plants.

This review aims to approach membrane technology to a circular economy, where a “waste” (discarded membranes), can be turned into a resource (recycled membranes for other uses) covering the whole life cycle of RO membranes: from the new development of antifouling membranes to the management of theses membranes when they become a waste.

Currently, the Membrane Technology Group of IMDEA Water, in cooperation with Sadyt and Valoriza Agua are developing the European Project TRANSFOMEM (LIFE+2013 ENV/ES/000751). Through project they are successfully transforming discarded RO membranes in nano- and ultra-filtration membranes. The project is in a pilot stage and is opening an application field for recycled membranes, which could have a potential market at industrial level if the recycled membranes are competitive in terms of cost, effectiveness, durability, energy requirements and maintenance.