Part of the Cobra Group, TEDAGUA (Técnicas de Desalinización de Aguas, S.A.) is a leading company in the design, manufacture, operation, maintenance and engineering of desalination plants, drinking water treatment systems and purification of water for drinking purposes and/or processes, as well as urban and industrial wastewater treatment and reuse.
Thanks to the growth it has experienced in recent years, TEDAGUA is now considered one of the main companies in the water treatment sector in Spain, where it is based, with important contracts in the five continents. Raúl Fernández, Head of the Engineering Department, and Álvaro Diaz del Rio, Head of the Innovation Department, tell us in this interview about the company's main projects in the field of desalination, and analyse the current landscape of desalination and the main innovations.
Why is it important to invest in non-conventional water resources such as desalination?
Raúl Fernández (R.F.): Historically, human settlements have been located in strategic areas with, among other things, easy access to water sources suitable for consumption, and have depended on them for their permanence or growth. In recent times, five factors have modified this relationship:
- Water sources are becoming increasingly polluted, whether surface or groundwater; intense human activity has been systematically contaminating water sources, which complicates using them directly.
- The world's population has grown greatly and unevenly, which has meant a great increase in pressure on freshwater resources, which in many cases they cannot withstand, leading to resource depletion and environmentally unsustainable situations.
- Climate change is a reality that is leading us to extreme meteorological regimes, with increasingly severe droughts and heavy rainfall that make it very difficult to plan and manage water resources so that water for essential uses is always available. Let us not forget that a large part of economic activity is linked to the availability of water of suitable quality.
- Fortunately, environmental awareness at the global level has become a very important decision-making factor for water projects. Building reservoirs, authorizing increases in groundwater withdrawals, reducing river flows, using river water for cooling, authorizing discharges, etc. are projects with important environmental impacts which, in many cases, prevent project implementation.
- Lately, the water availability-human settlement nexus has broken due to economic factors. Massive urban development in desert areas is a reality, driven solely by economic reasons, whether it is the availability of other resources or tourism interests.
All of these factors make non-conventional water resources increasingly necessary. We need to increase the available resources through desalination and to recycle wastewater so it can be reused. Projects linked to both technologies, if not directly using both, are becoming increasingly common and interesting.
The challenges facing the sector: energy efficiency and environmental footprint are making technological advances and disruptive proposals part of our daily work.
Álvaro Díaz del Rio (A.D.R.): The world is at a critical moment with respect to water resources management; the gap between available water and the demand for this basic resource is increasing at a faster and faster rate. With regard to demand, it is estimated that by 2050 the planet will have 9.5 billion inhabitants, a 20% increase in just thirty years, which is a challenge for the sector. This implies increasing agricultural production, agriculture being a major water consumer, and also increasing industrial output, where processes are increasingly water-intensive. A clear example of the latter is the much talked about generation of green hydrogen by electrolysis as the energy source of the future. The European Union aims to have at least 40 GW of installed capacity by 2030, and let's not forget that to generate this hydrogen we need ultrapure water. Another example of a water-consuming industry is microchip manufacturing, a sector that is increasing its production exponentially in an increasingly digital society, where for each microchip manufactured, some 130 litres of water are consumed.
"The reality of climate change, coupled with the pollution of conventional water sources by human activities, results in a reduction of available conventional water resources", Alvaro Diaz del Rio
On the other hand, the reality of climate change, coupled with the pollution of conventional water sources by human activities, results in a reduction of available conventional water resources. This decline in available resources is worsening, and is linked to economic growth.
Considering that approximately two thirds of the planet's surface is covered with water, but only 2.5% of this water is freshwater, and only 0.3% is suitable for human consumption, desalination is the main solution to bridge the gap between available water and water demand. We cannot expect unlimited economic growth in a world with finite resources.
Could you tell me about the company's desalination experience and key data?
A.D.R.: Tedagua began its activity in the field of desalination by developing modular and compact solutions that are characterized by their zero or minimum civil works requirements, an activity that Tedagua continues to develop today. A clear example of the success of these solutions was the two portable plants provided by Tedagua after the eruption of the volcano in La Palma (Canary Islands, Spain) in 2021 to supply water for crop irrigation in the area.
Portable desalination plant in La Palma (Credit: Tedagua)
Tedagua has more than twenty years of experience in the design, construction, operation and maintenance of all types of conventional plants, from desalination plants built for hotel complexes or small farms in the Canary Islands, to large seawater desalination plants such as Escombreras in Spain with a capacity of 63, 000 m3/day or those of Provisur in Peru, Tuas III in Singapore, Beni-Saf in Algeria or Spence in Chile with capacities of 35,000 m3/day, 163,000 m3/day, 200,000 m3/day and 87,600 m3/day respectively.
Escombreras desalination plant (Credit: Tedagua)
In total, Tedagua has designed and built more than one hundred desalination plants, which is more than 1,500,000 m3/day of desalinated water capacity in total.
What are your most important projects in this area at the moment?
R.F.: We are currently completing a seawater desalination project in Chile to supply water to a mine. It is very interesting because mines in Chile can no longer grow at the expense of increasing surface water withdrawals, so they are forced to look for new non-conventional water sources. This way, environmental values are preserved while allowing the economic development of the region.
Another environmentally interesting project is the seawater desalination plant for the "Salto de Chira" project in Gran Canaria. This desalination plant will be used to refill the Chira and Soria reservoirs for energy storage with energy produced using renewable technologies. The surplus water production will be allocated to irrigation, so the sodium adsorption rate (SAR) of the product water has been adapted to the values required by irrigators. In this project we can see both a sustainable use in terms of energy production and the contribution to irrigation. Involving not only different technologies, but also different uses, maximises the efficiency of these facilities, acting as a lever of added value.
Spence desalination plant in Chile (Credit: Tedagua)
The East Bay project in the Philippines is also worth mentioning. In this case we are talking about a drinking water treatment plant using fresh water from a lagoon. The quality of the raw water is very poor due to environmental pressures; it is polluted and has excess nutrients, making direct use very difficult. The plant we are building there is capable of removing all pollutants, as well as treating the seasonal salinity of the water by means of a reverse osmosis line. This way, using very different technologies in the same plant and adapting the treatment line to each situation, we are able to guarantee the availability of drinking water at all times in an area that urgently needs it. The project will improve the living conditions of thousands of people in the area.
On the other hand, we are building a seawater desalination plant in Nemmeli, Chennai, India, with a capacity of 150,000 m3/day, to provide quality drinking water to the Chennai metropolitan area. This desalination plant is equipped with a very complete pre-treatment system capable of dealing with significant variations in the quality of the incoming water. Construction is well underway and mechanical and electrical assembly will begin shortly.
The Sfax seawater desalination plant in Tunisia is also an important project for our company. North Africa has always been a prime market for us. Capable of producing up to 200,000 m3/day of drinking water, it will be built in a short period of time. In this case, construction work has not yet started, but will begin shortly.
"Another environmentally interesting project is the seawater desalination plant for the "Salto de Chira" project in Gran Canaria", Raúl Fernández
I would also like to mention the Taif wastewater treatment plant in Saudi Arabia, with a treatment capacity of 100,000 m3/day, which can be expanded to 270,000 m3/day. It is a wastewater treatment plant, not a desalination plant, but it comprises an exhaustive water treatment process that allows the reuse of the treated water, as well as comprehensive sludge treatment to ensure the maximum degree of sanitation. This plant, the first of its kind to be built in Saudi Arabia, will lead the way for other ones, and we are very proud to be at the forefront of this type of technology. As I said, reuse and desalination are going to be key in the immediate future to supply the water needed to meet the challenges posed by climate change.
What are the latest innovations in desalination?
A.D.R.: The most established and consolidated technology for desalination today is reverse osmosis using membranes, which represents about 71% of the technology worldwide.
This technology is currently the most efficient, but it still presents challenges that need to be addressed by the different players in the sector.
The first of these challenges is reducing the amount of energy consumed during the desalination process. Reverse osmosis is based on applying high pressure to the water, thus consuming a lot of energy. Currently the energy consumption of a medium and large scale desalination plant is around 3.0 Kwh/m3 produced, and below 2.2 Kwh/m3 for a small scale plant.
There are different lines of research that seek to improve the performance of this technology and others in parallel that seek disruptive technologies that overcome the implicit limitations of reverse osmosis.
Tedagua is committed to the search for disruptive technologies, based on the principle of potential difference for ion removal, such as electrodeionization or capacitive deionization. The main challenge is to find materials with suitable physicochemical characteristics to manufacture electrodes that optimize the processes of adsorption and desorption of salts.
However, there are research projects based, for example, on the potential difference between water streams with different salt concentrations.
Another technology that may have an application for small flows is that where the energy provided to the process comes from the treatment of wastewater using microbial fuel cells.
However, the most mature trend nowadays is undoubtedly combining desalination processes with renewable energies to reduce their environmental impact, where energy storage technologies will play a fundamental role.
The other challenge of reverse osmosis is the production of brine during the process. This concentrate is a waste that needs to be properly treated, but what is currently considered an environmental problem may turn into an opportunity with the extraction of critical raw materials.
There is already talk of "brine mining" as a source of metals, salts and chemical products obtained from this concentrate. Elements such as lithium, potassium or phosphorus can be extracted by different processes. Here again, the challenge is to find an efficient and cost-effective extraction process.
In this regard, there are many international projects that seek to optimize traditional extraction processes such as evaporation-crystallization, while others are studying disruptive and unconventional methods for obtaining these minerals.
In any case, we must celebrate that innovation strategies are evolving towards a more open ecosystem. Traditional research, development and innovation is a fundamental pillar of the innovation system, but it cannot be the only one.
Open Innovation accelerates industrial development processes, involving and strengthening ties between universities, technology centres, large companies, SMEs, startups, entrepreneurs, public authorities and institutional and private investors. Each of these actors plays its role in the innovation value chain, thus generating an ideal breeding ground for the generation of new ideas.
In recent years, the water sector has been accelerating its adaptation to this new way of innovating, which is more collaborative, more efficient and, most importantly, a win-win situation.
How do you see the current outlook for desalination worldwide?
R.F.: Globally, desalination is positioning itself as an essential need. The outlook is quite positive for the sector, although we must be very aware of the challenges we are facing: energy efficiency and environmental impact. All the actors involved are researching new ways of undertaking projects, contributing our added value.
A.D.R.: Desalination needs are very diverse worldwide. Due to environmental, climatic and socioeconomic factors, there are two large regions with greater growth potential than the rest: the Middle East-North Africa and Latin America.
Large investments are expected in the coming years, with the Middle East standing out above all others due to a combination of key factors such as the availability of economic resources, rapid economic growth and severe water stress.
In Latin America, in regions such as Chile and Peru, where mining is a major economic activity, desalinated water has become a critical supply, especially in areas around the Atacama Desert. There is great awareness by public authorities and the private sector of the need to increase the number of desalination plants, but these ideas must materialise into concrete projects.
Provisur desalination plant, Peru (Credit: Tedagua)