Desalination and sustainable water solutions: An interview with Dr. Corrado Sommariva

International Desalination Association president Dr. Corrado Sommariva shares how the environmental impact of desalination can be reduced and why material selection is important.

This feature news is part of Singapore International Water Week’s (SIWW) series of one-on-one interviews with global water industry leaders, Conversations with Water Leaders. In this edition, Dr. Corrado Sommariva, president of the International Desalination Association (IDA), shares with OOSKAnews correspondent, Renee Martin-Nagle, the various desalination technologies and management of environment footprint from desalination operations.

From a rich desalination background, Dr. Corrado Sommariva speaks on the role of desalination in the Middle East and also recent activities of IDA.

Good morning, Dr. Sommariva. You have worked for many years in the Middle East where the arid climate has caused those countries to rely heavily on desalination for many years. How would you describe the role of desalination there?

Desalination has provided a reliable source of fresh water in the Gulf region for nearly half a century, and real development in the Middle East was only possible with the parallel development and implementation of desalination. Some countries in the Gulf region rely on desalination to produce 90 per cent or more of their drinking water, and overall this region has about 40 per cent of the world’s desalinated water capacity. Since there are no natural resources and water storage is limited to 24 hours, the emphasis has always been on reliability and robustness of operation. Today a gradual but constant effort is taking place towards more sustainable water solutions that would enable a lower energy footprint and environmental impact.

Various desal technologies are in use, including multi-stage flash distillation (MSF), multiple effect distillation (MED), reverse osmosis (RO), seawater reverse osmosis (SWRO), and forward osmosis (FO).  Nanofiltration in a tri-hybrid application is a recent option, and then there are the chemical processes, such as electro-dialysis de-ionization (EDI) and low-pressure distillation (LPD). Solar membrane distillation systems are being piloted, and Egypt is testing a low temperature distillation (LTD) system to reduce the need for heat and thus energy. Which technologies do you believe will be the trends for the future?

Thermal desalination technologies have been traditionally less energy-efficient than membrane processes, such as SWRO. The two major thermal desalination processes are Multi-Effect Distillation, or MED, and Multi-Stage Flash, or MSF. MED technology is substantially more energy-efficient than MSF technology, and in some cases, even more energy efficient than RO. For many years, MED technology could not find an entry point in the implementation of large scale projects, but it has now found its way into the market as there is a serious technology drive towards increasing the distillers’ performance ratio. Whereas 10 years ago, one distiller could produce 7 kg of distillate water per kg of steam, the trend is now more towards 9 or 10 kg.  There are a lot of very good concepts in the market, including forward osmosis, membrane distillation, tri-hybrid applications and low temperature distillation. These are excellent concepts that can challenge established technologies.

One of the major challenges for desalination is the intense amount of energy required for the process, which emits greenhouse gases that have been linked to climate change. How can a lower energy footprint be achieved?

The main obstacle to matching desalination with solar power is the intrinsic high-energy footprint associated with the desalination technologies. Finding a way to couple a desalination concept to a renewable source is not a technological challenge. Reducing the energy footprint is.

Two levels of actions require urgent attention. The first one is the creation of policies that encourage energy efficiency, providing a realistic price for energy even in oil-rich countries and rewarding energy efficiency. On the technical level, it is necessary to educate managers and plant operators on how to operate plants in a much more energy efficient manner with relatively few changes.

Solar power seems like an obvious choice to provide energy for desal operations in an environmentally friendly way, especially in an area like the Middle East where sunshine is plentiful. What are the barriers to solar power for desal?

The main obstacle to matching desalination with solar power is the intrinsic high-energy footprint associated with the desalination technologies. Finding a way to couple a desalination concept to a renewable source is not a technological challenge. Reducing the energy footprint is. The same applies to SWRO, which can be easily powered by photovoltaic.  

The MASDAR project, supported by IDA, is promoting the use of new technologies having a lower energy footprint and therefore capable to be more easily matched with renewable technologies. Concepts such as forward osmosis, membrane distillation and tri-hybrid applications are rarely given a chance beyond the laboratory or pilot scale project. Therefore, there is a risk that some of them will never be able to develop into an industrial reality.

You have lectured at Genoa University on material selection in desal plant construction. Why is material selection so important for desal plants?

Material selection is extremely important for the lifetime planning of a desalination asset. Seawater is generally corrosive, but, when used for desalination, seawater needs to be chlorinated, and this makes the corrosion potential worse. For thermal desalination where seawater is used at high temperature, the corrosion potential becomes even worse. Therefore, for thermal desalination, copper-nickel alloys and duplex stainless steel are used for the heat transfer tubes and evaporator shell construction. This makes these technologies extremely sensitive to market price indexes for metals, and the CAPEX [capital expenditure] is very sensitive in these aspects. SWRO technology relies heavily on super duplex stainless steel, but generally plastic or GRP [fiberglass pipe] is used for all low pressure applications. Materials science in desalination is developing fast and may offer new and more cost effective solutions.

In addition to the greenhouse gas footprint of desal operations, the resulting brine that is left over after extraction of fresh water presents another environmental issue. How should the brine that results from desal be managed?

There is a little bit of misconception about the impact on coastal ecosystems from brine discharge. A desalination plant does not make anything “new” but instead returns to the sea the same salts that have been abstracted from the sea, although at a higher concentration. Residual chlorine concentration in seawater discharge is generally very low due to the chlorine absorption in the process of seawater sterilization. A great emphasis needs to be placed in reduction of chemicals — not only chlorine but antiscale and antifoam — whose residuals are discharged back into the sea, although the amount of chemicals that are used and discharged in desal is a small fraction of what other industries use. Locally, impacts can be mitigated with the use of diffusers that improve the mixing between the brine and the surrounding environment. A long term plan is the use of partial or total zero load discharge (ZLD).

More complex is the discharge from thermal desalination where, in addition to the salinity plume, a substantial thermal plume is discharged to the sea. The best way to combat this effect is to increase the efficiency of the thermal desalination plant. In this manner, less energy is required to produce water, and less energy in the form of heat is discharged back to the sea.

The IDA World Congress on Desalination and Water Reuse will be held in Tianjin, China from 20-25 October. What do you see as outcomes of the Congress?

The IDA World Congress is the world’s premier event for the global desalination community, and the theme of this conference is “Desalination: A Promise for the Future”. China is a very important emerging market for desalination and has established some ambitious goals for desalination as part of its 12th Five-Year Plan, so the timing for this event is ideal. The programme is strongly oriented towards innovation and sustainability, and efforts in the direction of energy efficiency are a major topic. IDA has put a lot of efforts in the last six years towards environmental, energy and social responsibility and innovation targets. I trust that the conference will represent a platform to develop these efforts further and create an awareness of what can be and needs to be achieved.

There is a little bit of misconception about the impact on coastal ecosystems from brine discharge … Locally, impacts can be mitigated with the use of diffusers that improve the mixing between the brine and the surrounding environment. A long term plan is the use of partial or total zero load discharge

Singapore has been in the forefront of many of the leading technologies and practices in fresh water management. In your view, how has Singapore contributed to the global water dialogue?

The role that public corporations such as PUB [Public Utilities Board] have in the promotion of sustainable goals is unique. In general, innovation and particularly R&D is very often led by the industry to design new products that allow a manufacturer to get an edge on the competition. In Singapore, the driving force is coming from the public sector, which has always put a direct emphasis on innovation and R&D in relation to the sustainability goals for the community. I believe we all should thank Singapore for having been always a role model in creating awareness of water solutions and pursuing new ideas and models of water efficiency and environmental stewardship.

After being elected as president of IDA in 2011, you said you wanted to bring the IDA and the industry closer. What steps have you taken to achieve that goal?

There are players in the industry who are not yet aware of what desalination could achieve and are also not aware enough of what IDA can offer – particularly key figures in the planning and decision-making of desalination projects. I believe that greater involvement with IDA would lead to more informed decisions during the initiation of projects. A sharp step forward was made with IDA’s support of the IWS [International Water Summit] and the MASDAR initiative where for the first time in its history, IDA has been a supporter and endorser of a state initiative. We reached North Africa with our first conference in Casablanca in 2012, and we are planning our first large conference in Latin America.

Also, within the last two years, we established the IDA Desalination Academy and have conducted the first training seminars. We have established strategic alliances to support the Academy’s programmes, including an alliance with Heriot-Watt University leading to a Master of Science degree in Desalination, courses with PUB, and an online course with David H. Paul, Inc., leading to an international certification in reverse osmosis for plant operators.

I’m sure that the time has passed quickly, but you are nearing the end of your two-year term as president of IDA. As you reflect on your term in that office, what activities would you like to highlight?

I am particularly proud of the IDA Humanitarian Outreach Program through which IDA sponsors conferences whose net proceeds are donated to water-related humanitarian projects.  For example, the “Desalination Industry Action for Good” conference in Portofino, Italy, raised US$120,000 – US$60,000 each from IDA and Rotary International — to help alleviate water shortages for residents of Ankililoaka, Madagascar. The recent conference “Desalination for Oil and Gas Industry” in Banff, Canada, raised almost US$500,000. The outreach programme means a lot to me.

You have enjoyed a long, active and distinguished career in engineering and water. What advice would you give to young people who are just starting their careers?

Love for what you are doing is generally the key of success in all human activities, and to the young readers starting their careers, I cannot recommend anything else but to love their job. Those in desalination should think of themselves as the inventors of new solutions that will solve the next generation’s water problems, which can inspire them throughout their careers to continue their development. I would encourage them to not only acquire substantive technical information but also continue their professional growth and contribute to the industry. Each one of us should recognise that our work can make a difference to many others’ lives in a unique and meaningful way.

What final message you would like to leave with our readers?

Finding new and sustainable ways to produce water is a tremendous social responsibility that we all hold towards our future generations. We must never be complacent. We must continue to innovate and find new solutions for better and more sustainable water production.  In this way, desalination has a lot to offer to humanity.

I also believe that working with this sense of responsibility will make us discover that water connects us and is a common denominator to find solutions well beyond the borders defined in the water market.

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