Technological Centre

CETIM obtains high quality reuse water in its R&D projects

Today we celebrate World Water Monitoring Day by reviewing regulatory developments in water reuse in Spain and Europe, and how these affect our R&D projects and research in wastewater treatment.

Over the last few years, drought and water scarcity have become a matter of concern for the world’s society. For this reason, European Union has taken legal measures that respond to the pressures on water resources. One example is the recent Regulation (EU) 2020/741, which entered into force in June 2020 and became applicable in June this year. This regulation sets minimum water quality and monitoring requirements for the reuse of treated water for agricultural irrigation.

The minimum requirements cover the minimum frequency of routine monitoring, the validation monitoring characteristics and are set according to the water quality class. In this way, and following European legislation, we can categorise the quality of reuse water as follows:

  • Class A: This is the label with the most restrictions, as it implies that the water obtained is the purest. It can be reused in food crops that are consumed raw and in those where the edible part is in contact with reclaimed water.


  • Class B: Water can be reused on food crops that are consumed raw when the edible part is produced above ground level and is not in direct contact with reclaimed water, as well as on processed food crops and non-food crops (including crops used to feed dairy and meat producing animals). Under this label, all irrigation methods are covered.


  • Class C: Has the same application as the previous label, except that the irrigation system would now be drip irrigation.


  • Class D: Corresponds to the least restrictive label, as water reuse is allowed for crops grown for industry, energy and seed production.


In Spain, we also have Royal Decree 1620/2007 which regulates reuse for agricultural irrigation, urban uses, industrial uses, recreational and environmental uses. If we compare both regulations, we will see that the Spanish law contemplates more areas of reuse and is less restrictive compared to the European regulation. The latter also requires a validation control, carrying out a more exhaustive evaluation of microbiological pollutants.

How do laws affect our water treatment R&D projects?

In the project we are leading, LIFE GREEN SEWER, we are researching the development and validation of a new secondary wastewater treatment system, allowing, at the same time, the recovery of energy and resources and reducing the presence of pollutants, costs and energy consumption. The project involves a consortium formed by CETIM, Emafesa, Magtel, Socamex  and the University of Barcelona.

After installation of a pilot plant at the EMAFESA wastewater treatment plant in Ferrol, we managed to eliminate 92% of the emerging pollutants present in the wastewater, with a removal rate of 90%. As a result, we obtained high quality treated water for agricultural irrigation class B, according to Regulation (EU) 2020/741.

Another success story is our LIFE DRAIN RAIN project, in which we developed a new system for treating particularly polluted water (port esplanades, naval industry, machinery parks, etc.), which eliminated the pollution that rainwater carries with it, causing significant damage to the environment. In addition, the system made it possible to store this rainwater and treat it for subsequent reuse.

This water obtained in the project reached the quality required by the legislation for urban uses (irrigation of green areas, street washing, fire-fighting systems or industrial vehicle washing) according to Spanish law, but it could also be used as reuse water for growing food for raw consumption, non-food crops or crops for industry and energy production, thus applying European regulations.

Implementation of LIFE DRAIN RAIN in Calasparra, Murcia.

The importance of legislating

The adoption of Regulation (EU) 2020/741 has established a legal framework for member states that promotes agricultural water reuse, ensuring the protection of the environment, human and animal health. It also contributes to the sustainable and responsible use of water resources, promoting the circular economy of water and mitigating the effects of climate change.