RECYCLING OF MEMBRANES USED IN DESALATION ALLOWS THE REUSE OF RESIDUAL WATER

The importance of water is vital; Is a finite and vulnerable resource that must be taken care of to achieve the objectives of sustainable development. Only 3% of the planet's water is fresh water, it is increasingly contaminated and distributes irregularly. The World Resources Institute (WRI) places Spain in the 32nd position in the countries with the highest water stress in 2040. 

Spain is one of the most advanced countries in the field of water sector technologies. The shortage of water resources on the Mediterranean coast, as well as in the island archipelagos and in the south of the peninsula has caused Spain to invest in the use of unconventional water sources such as salt water and waste water. 

In this way, Spain has more than 950 desalination plants capable of generating more than 5.4 million m3 of drinking water per day [1]. Most of these plants use reverse osmosis membranes. The deterioration of the membranes due, mainly, to problems due to fouling, makes their useful life between 5 and 10 years [2]. Based on these data, it is estimated that in Spain, more than 80,000 membrane modules are discarded annually in landfills [3]. 

The Membrane Technology group of the IMDEA Water Institute works in the recycling of these membrane modules through two projects: TRANSFOMEM (LIFE13 ENV / ES / 000751) and INREMEM (CTM2015-65348-C2-1-R). 

The objective of this research is to promote the circular economy in the desalination sector, taking advantage of the residues derived from its activity (discarded membranes) and converting them into new sources of resources (recycled membranes). 

These recycled membranes can be reused in other uses such as, for example, tertiary treatment of waste water. Recycled membranes are capable of separating persistent organic pollutants, bacteria and viruses that do not degrade in a conventional secondary treatment. With this new stage of treatment, you get an effluent that can be safely used in different uses, such as agriculture, irrigation parks or street cleaning. 

Using unconventional water sources such as salt water and wastewater, pressure on Spain's water resources is reduced, so that more fresh water is available for human consumption, recreational use and conservation of ecosystems.