25 january 2017

Preserving water through desalination

An opinion piece by Hervé Faujour, Technical and Performance Director, Veolia Middle East.

Big Problems Call for Big Ambitions.
In front of the many environmental challenges such as global warming, world hunger, exploding urbanization and resource scarcity, Veolia has adopted a new mission: “Resourcing the World”. It reflects the company’s determination to help break our dependency on resource consumption and switch to a sustainable use-and-recover approach. The solutions Veolia delivers to its customers provide access to needed resources while at the same time preserving and replenishing them. This principle applies very much to the desalination which is a vital need in arid areas such as the Middle East, while ensuring long term stability by minimizing its impact on the environment We can use the famous “3R” principle – Reduce / Reuse / Recycle – to tackle the various environmental challenges of desalination in a structured way and to not only focus on the sea water desalination but to cover the complete water cycle.

Raising awareness to the customers on how precious water is by providing them accurate information, and minimizing the leaks through rolling out of smart water systems in the city is the first and most effective way to preserve the water resource. Such an approach has been implemented in Riyadh very effectively by National Water Company and Veolia to identify possible reductions after the water meters, by identifying leaks and promoting better practices within domestic households.
A significant amount of desalinated water can be wasted in potable water networks through leakage. Reducing such wastage is always the first step and it is even more critical in desalination considering the much higher cost of water production compared to conventional potable water production. Many examples of leak reduction in the network can show how effective it is, including for instance the 19 billion liter leak reduction strategy planned in Oman in the coming two years. The means to achieve such results include monitoring the network pressure to reduce the flow of leaks, early detection of leaks and even anticipation of sections of the network that would require preventive maintenance. Veolia’s offering to bring such value to potable water distribution is the Smart Water Box, a standardized approach rolled out in a few cities around the world such as Lyon.

Water reuse is quite widely spread across the Middle East thanks to a visionary infrastructure for new development. Along with the usual sewerage and the potable water networks, there is often a third network, for Treated Effluent in order to distribute water that can be used as a substitute to potable water in many applications. It can cover irrigation for landscaping, wetlands refill, as well as district cooling water top-up, industrial process water or aquifer recharge. These examples of reuse require advanced treatment to further polish it, along with strict control of the water and air quality to ensure full compliance to the applicable standard: not to have any adverse consequences on public health. Providing effective sewage treatment system also has a positive impact on the environment, in addition to reusing the effluent: the water demand for reuse is still not as high as the  treated effluent flow, therefore an excess of water is still discharged to the environment, mainly to the sea. Some relation has been demonstrated between the treatment standard for wastewater, especially on nutrients and the occurrence of algae bloom or red tides, which can have immediate effect on the performance on the desalination and other coastal industries. Considering the complete water cycle and providing effective sewage treatment for reuse is therefore an effective way to minimize the impact on the environment, reducing the need for potable water and to secure the potable water production system.

Water recycle and water reuse are generally interchangeable phrases, but there are other resources that are recycled in the desalination process. Energy recycling is a major environmental contribution to the desalination process. There are two main processes to desalinate seawater; thermal desalination and reverse osmosis (RO).They both require very large amount of energy, but this need has been greatly reduced in the past decades through energy recycling. In thermal desalination, MultiEffect Distillation (MED) uses low pressure steam which is the low grade waste heat from a local power plant, reducing the need to import electricity. In Reverse Osmosis, high pressure water is filtered through fine membranes to purify the water. Veolia is currently working at optimizing the energy in a RO pilot program with Masdar Institute in the UAE. Using a new energy recovery system it is possible to avoid additional high pressure pumping of the water to the membranes. This is done through the conversion of pressure from the brine into the inlet water before it is disposed back to the sea.

Desalination in the Middle East therefore has a minimized environmental footprint due to its reduced energy demand, on an optimized potable water network with lowered water demand thanks to the reduce, reuse, recycle principles applied. Sustainability is not only related to environment however. It also covers human aspects which we could describe as the“3S”: Social / Safety /Security.

The social benefits of desalination are great, as has been demonstrated in the Sur region of Oman. The construction of a localized desalination plant was a pre-requisite for the development of the industrial development in the region which has greatly benefited the local population. An important focus on training was given to meet the Omanisation targets. This was managed with great success, for instance providing a gradual promotion of an Omani employee from the initial small desalination up to the General Manager of one of the key references on desalination, as well as many others.

As potable water sources are very scarce in the region the security of that supply is paramount and alternatives such desalination plants are strategically essential. No compromise made on the availability of the plant under any conditions. Fujairah plant has been able to exceed the strict requirement of 98% reliability since its start up thanks to robust treatment steps against red tides, along with technical excellence on ensuring proactive maintenance under very tough conditions of saline, hot and humid environments, very high pressures and corrosive fluids.

To conclude, I would take what comes first in Veolia: Safety. Desalination is a sensitive process, with various high pressure and high temperature risks. Specific procedures related to such processes have been rolled out in the past decade in Veolia, with strict Go-NoGo check lists for startup, specific training and procedures and policies, especially regarding isolation of equipment.

By providing efficient potable water production and distribution, promoting efficient sewage treatment for reuse, whilst focusing on the human social impacts and benefits to the local community desalination can provide a reliable, secure water system and safe environment for the people and so preserving water for the future.