"Water resources management in 21st century agriculture".

On the other hand, world population growth will require a doubling of food production by 2050, according to the United Nations, with agriculture being the world's largest consumer of water resources (70%). 

In this situation of water scarcity, it is necessary to search for other water resources, such as the so-called "non-conventional" ones (desalination and reuse), in order to meet the growing demands of the population and food production. 

While the use of desalinated water for agriculture is practically irrelevant worldwide, representing no more than 2% of total uses, Spain is a rarity in this respect, being the country with the highest use for this application, with values of more than 21%. 

In Spain, the structural water deficit has led farmers in eastern Spain to rely on desalination as part of their water resources, integrating surface water from water transfers, groundwater, reused water and desalinated water (brackish and seawater), thus obtaining a reasonable price thanks to the mixture of all these inputs. In addition, the high returns on investment in greenhouse crops, which are highly technified with off-season products, make the cost of desalinated water affordable within the production costs for this sector of high quality products. It should also be noted that it has been demonstrated (in research projects such as the LIFE Deseacropof Sacyr Water) that the use of desalinated water for agriculture increases productivity and product quality.  

Similarly, the reuse of water resources makes it possible to reuse water once it has been used for municipal, industrial or agricultural purposes. In order to be able to offer this second use to water, it is necessary to apply an additional treatment to the conventional purification treatment (known as tertiary treatment), which can be more or less complex depending on the quality of the purified water and the use for which it is going to be used. 

Re-use allows for a more sustainable water managementIt increases available resources, reduces the negative effect of wastewater discharge into water bodies and reduces pressure on surface and groundwater resources, and is even more positive when carried out in water-stressed coastal areas as it releases flows that would otherwise be lost to the sea. 

In order to incorporate this resource into water planning, several important aspects must be taken into account; the applicable legal framework, the reduction or elimination of health risks through regulation and best practices and technologies, the price must be competitive including transport to the end user, and there must be a conscious acceptance by the end users through adequate communication. 

It should be noted that Spain is the 5th country in the world and the first in Europe in terms of installed desalination capacity, and is also the European country with the greatest wastewater reuse capacity, which means that we have a great deal of technological experience and experience in the application of these resources to agriculture. 

We should mention that in 2020 the European Union published a new regulation on the reuse of treated water for agriculture, which comes into force in June and which will require some improvements in some facilities, especially in terms of disinfection. 

As a recent development, on 11 May 2023, the Spanish government, through the Ministry for Ecological Transition and the Demographic Challenge (MITECO) published a press release on a new Royal Decree that was published the following day on new drought measures, summarised as follows: 

• 2.2 billion in total.
• Tax and fee exemptions for drought-affected farmers are included.
• The water law is amended to increase the use of reclaimed water from the current 400 Hm3/year to 1,000 Hm3/year by 2027. 
• Investments in decarbonisation (photovoltaic plants) are included.
• The construction of new desalination plants (Tordera II, Costa del Sol and Levante Almeriense) is accelerated.
• Major investments are made in new large tertiary treatment plants such as Rincón de León and Monte Orgegia in Alicante.

In addition, the extensions of the two largest desalination plants in Spain and Europe, Águilas and Torrevieja, were already approved and will probably be put out to tender this year, as well as the publication of a new PERTE for the digitalisation of the water sector for agriculture. Likewise, some regions such as Murcia or the Valencian Community have announced additional tax reductions for desalinated water for agriculture. 

All these achievements in technology and water supply through non-conventional resources would not be possible without the development of innovation in our companies, administrations and research centres, also world leaders in the water sector.

Innovation is an essential tool in the development of these technologies: new trends in water innovation are always oriented towards increasing sustainability, such as the recovery of valuable components from wastewater or brine (e.g., the recovery of wastewater or brine).brine mining), the circular economy, increased efficiency and the use of renewable energies and digital transformation. 

In this sense, the SOS-AGUA-XXI project, "Sustainability, Water and Agriculture in the 21st century", is an example of the development of technologies for the future of agriculture, including aspects of water quality, digital transformation and nutrient recovery, etc. 

SOS-AGUA-XXI Project

The project SOS-WATER-XXI is a major research project with a budget of EUR 6 million funded by the European Commission. Centre for Technological Development and Innovation (CDTI) as part of the Missions 2021 call for proposals with the European Next Generation funds, with the aim of developing 21st century agriculture. The project will run from 2021 to 2024 and is being developed by a consortium made up of the companies Sacyr Agua, Valoriza Servicios Ambientales, Regenera, Bosonit, Tepro, Fora forest technologies, Aeromedia and Aquadvise and a group of universities and research centres (University of Alicante, University of Alcalá de Henares, Polytechnic University of Cartagena and the Association for Research and Industrial Cooperation of Andalusia (AICIA)).  

The general objective of the SOS-AGUA-XXI project is to research technological solutions that, taking sustainability and energy efficiency of the proposed processes as a maximum exponent, allow the development of strategies for the efficient management and treatment of water resources for the agricultural sector.  

Development of agriculture in the 21st century (35 tasks, distributed in six lines of research) 

1. Digitalisation and the incorporation of new technologies in 21st century agriculture. 
2. Improvements in water quality and the use of non-conventional resources for agricultural irrigation (among others, detection and treatment of compounds of emerging concern in reused water, detection and reduction of boron in desalinated water, new disinfection systems, search for crops more resistant to salinity, use of aerial and underwater drones). 
3. Recovery of nutrients and compounds of interest from different types of waters (recovery of nutrients from different types of waters with microalgae, recovery of salts from brines (brine mining) and waste water, production of green hydrogen from reclaimed water, etc.). 
4. Integrated economic and environmental studies (water balances in the study area, economics and environmental aspects of the proposed measures and how they affect the project, energy efficiency, calculation of water and CO2 and socio-economic impact) 

The importance of digital transformation in this project should be emphasised. The digitalisation line includes tasks such as: 

• Predictive water and energy modelling.
• Predictive models of extreme weather events and how they affect infrastructures.
• Design of irrigation models based on new technologies.
• Use of aerial and underwater drones.
• Digital cufflinks.
• As well as application of different models to the different tasks of the project (microalgae, compounds of emerging concern, etc.).  

In conclusion, the SOS-WATER project aims to develop 21st century agriculture. Efficient in the use of water and energy resources in a sustainable and resilient way, and the keys that underpin the project are: 

• The promotion of the use of non-conventional resources (desalination and reuse).
• Digitisation and incorporation of new technologies.
• Increasing water quality and by-product recovery by promoting the circular economy.
• Promote economically, socially and environmentally sustainable solutions.