Recovery of reverse osmosis membranes that have reached their end of life in desalination plants, typically between 5 and 10 years, is the main objective of this project, turning what is, today, considered a costly residue that is sent to disposal, into a valuable by product for re-use.

REMEMBRANE proposes a demonstration plant in which diverse mechanical and chemical treatments are developed in order to recover these membranes to reuse them in the same desalination process or in other applications which need a lower quality water specification but always in reverse osmosis technology (i.e. tertiary treatment of wastewater for irrigation and reuse, industrial water with low salinity requirements, etc…)

REMEMBRANE proposes an environmentally friendly and innovative technology that aims to improve the efficiency of membrane recovery for the same or some other application avoiding landfill disposal and lengthening membrane’s life cycle.
The main objectives of this project are:
1) Technological innovation. A mobile demonstration plant will be prepared to treat any kind of RO membrane at its end of life. The prototype will have three main modules: First of all, a test installation, where real membrane status will be diagnosed. Then, different treatments will be performed depending on the membrane and the type of clogging. Once it is clean, the final unit will test membrane stability with real inlet wastewater. It is foreseen that this unit is also portable so recovered membranes can be tested on site without interrupting day by day management.
2) Turning a residue into value. An increasing demand on water desalination means that more membranes are installed, leading to a bigger number of worn out membranes every year. These used membranes are presently sent to disposal. REMEMBRANE technology offers the chance of increasing the working life of these membranes by different treatments and reusing them in diverse applications.
3) Decrease on landfill disposal and use of resources. Reverse osmosis membranes are going to be recovered and re-used for other applications after applying our technology, avoiding them being sent to disposal for a prolonged time. As a complementary goal, less production of new membranes is needed since recovered membranes can fulfill various purposes, so fewer amounts of membranes are produced, worn out and sent to disposal, reducing the stress of resources caused by membrane fabrication and transportation.
4) Enhance regenerated water feasibility. Policies and legislation recommend the application of water reuse, but regenerated water cost remains an obstacle.

The technology proposed in REMEMBRANE aims to achieve a low price recovered membrane that decreases investment and also operation costs, allowing more use of RO and therefore increasing the quality of conventional physic-chemical treatments.
5) Dissemination of this new technology is considered as one of the most important goals of the project in order to facilitate the implementation of European Community Environment policies, with particular emphasis on implementation at local and regional level, allowing improved water reuse and reduced environmental impacts in Mediterranean countries.

Conclusions

  • Membranes are tougher than suppliers may say. It is possible to work with a membrane that has been poorly conserved after usage and make frequent chemical cleaning without degrading the active layer. Therefore, membranes can withstand “bad” storage conditions (dry atmosphere and high temperatures).
  • It is not easy to oxidise a reverse osmosis membrane with chlorine. Thus, it is possible to obtained customised membranes.
  • Cleaning recipes with chlorine are useful to upgrade “not recoverable” membranes.
    REMEMBRANE strategy has overcome an environmental problem related to the worn out reverse osmosis membranes. The technology proposed is sustainable and its benefits may be summarised in:
  • Recovery of a residue: Recovered membranes can be reused in RO applications
  • Reduction of landfill disposal: less membranes are going to be disposed at landfill since they are being reused, approximate 6.700 Tm/ per year less only in Spain.
  • Carbon foot print reduction using 226000 recovered membranes for one year in Spain may go from 5990 Tm of CO2 (worst case) to 8815 Tm of CO2 (best case).
  • Decrease in raw material production related to membrane manufacture: reusing worn out membranes has a direct effect on the number of new membranes needed and its environmental impact.
  • Increase of the regenerated water reuse due to the cost reduction related to the use of recovered membranes through REMEMBRANE process.

Other collateral benefits of the strategy proposed in REMEMBRANE aiming to give applicability, reproducibility and economic feasibility in the future market are:

  • Regenerated water use, i.e. for irrigation, will be cheaper with recovered membranes so application of this technology may be enhanced.
  • Membrane replacement will be cheaper than with new modules so operation costs will be reduced. From 350 to 100 €/module.
  • Reduction of the membrane’s management cost as a residue, including its carbon footprint due to transport.
  • Since membranes become cheaper, it would not be necessary to install intensive pre-treatment processes such as ultrafiltration or physicochemical operations to protect them; therefore, installation costs of the reverse osmosis plants will be reduced.
  • Appearing on the market of recovered membranes with a very low price, may cause that reverse osmosis membrane manufactures lower their prices
  • Tap quality guaranteed for stakeholders under fewer maintenance costs.
  • Increase of R+D from membrane providers to improve the resistance and work quality of new membranes
  • More benefits due to cost savings in industries that use intensively high water quality (beverages, fruit, etc.)