The United Arab Emirates (UAE) is a country that grapples with the challenge of water scarcity due to its arid climate and rapidly growing population. With limited freshwater sources, the country heavily depends on desalination for its water supply. In recent years, it has turned to advanced wastewater treatment solutions to meet some of the demands. This article delves into the intricacies of wastewater treatment, the challenges faced, and the innovative technologies transforming the industry. 

Dr. Mohamed Dawoud, Advisor - Environment Quality, Environment Agency Abu Dhabi, gave us an overview of the initiatives taken in the Emirate of Abu Dhabi to utilise treated wastewater. Abu Dhabi currently reuses only 60 per cent of about 284 million cubic meters of treated wastewater it generates each year and the rest is discharged into the environment, he said. But the government plans to fully utilise this valuable resource in different purposes including farm and forests irrigation, district cooling, and groundwater aquifer recharge to enhance the groundwater quality and potentiality in an ambitious environmental plan. This zero discharge policy should be achieved by the end of 2024, he added. 

Speaking about its importance, Dawoud said, “Wastewater treatment in the UAE and the Middle East region plays a significant role in meeting water needs and filling the gaps between supply and demand, particularly for non-potable purposes such as irrigation and industrial processes.” 

However, its effectiveness depends on several factors, including the quality of treatment, water reuse policies, infrastructure investments, and overall water management strategies. At present the wastewater in UAE is treated up to tertiary level which allows it to be reused in many purposes safely, he added. 

Governments in the Middle East have implemented policies to encourage the reuse of treated wastewater. “For example, the UAE has set ambitious targets for wastewater reuse to reach zero discharge into the environment by the end of 2024. These policies are essential for maximising the effectiveness of wastewater treatment in meeting water needs,” he said, adding that adequate infrastructure is critical for collecting, treating, and distributing treated wastewater. “Investments in wastewater treatment plants and distribution systems are essential to ensure that treated water can be effectively used. So, the Abu Dhabi Government spent about 1.0 billion AED on a new transmission and distribution network to utilise about 140 million cubic meters of treated wastewater in irrigation of farms and forests.” 

Challenges 

In the UAE, wastewater reuse and recycling face several challenges due to its arid climate, rapid urban development and lack of infrastructure. However, the government developed an ambitious environmental plan and strategy for wastewater reuse by investing in building additional infrastructures. Another notable challenge is the salinity of treated wastewater due to seepage from seawater to the collection network which is not treated by the treatment plants. “The government has initiated a two-year plan to minimise this seepage and improve the salinity by 50 per cent.” Developing and implementing appropriate regulations and standards for wastewater reuse is essential, he noted. “Establishing a clear legal framework can be complex and time-consuming. Developing the institutional capacity to manage and regulate wastewater reuse effectively is a challenge. The UAE government established necessary regulatory bodies, monitoring systems, and ensuring compliance to overcome these barriers.” 

In the UAE, treated wastewater is used at present for irrigation of forests, irrigation of farms, landscaping, amenity plantation and environmental conservation of places such as Al Wathba Wetland to reduce the demand on freshwater sources such as desalination or groundwater. However, there are other options for reusing treated wastewater such as Industrial Processes - Some industries in the UAE could use treated wastewater in their processes, particularly those that do not require high-purity water such as irrigation and outdoor uses. This reduces the demand for potable water in industrial operations; District Cooling Systems -  Treated wastewater can be employed in cooling systems for buildings and industrial facilities; Groundwater Aquifers Recharge - In certain areas, treated wastewater can be injected to recharge deteriorated groundwater aquifers. This helps replenish groundwater resources, which can be crucial for sustaining the water supply; Construction and Dust Control - Recycled wastewater can be used for construction purposes, such as dust control on construction sites and for mixing concrete. 

The UAE has invested heavily in advanced wastewater treatment technologies and infrastructure to ensure that treated wastewater meets the required quality standards for these various applications, Dawoud noted. Government policies and regulations support the responsible use of recycled wastewater to maximise its contribution to sustainable water management in the country. 

Technological advancements 

The field of wastewater treatment has seen significant technological advancements in recent years, driven by the need for more efficient and sustainable treatment processes. He highlighted some of the latest technological advancements in wastewater treatment. “Advanced membrane-based technologies such as reverse osmosis (RO), ultrafiltration (UF), and nanofiltration (NF), have become more efficient and cost-effective, especially due to low salinity of wastewater. Also, the Advanced Oxidation Processes (AOPs), such as photocatalysis and ozonation are used to break down organic and persistent pollutants in wastewater. They are effective in treating pharmaceuticals, personal care products, and emerging contaminants. The Biological Nutrient Removal (BNR) Processes have been enhanced to achieve better removal of nutrients like nitrogen and phosphorus. These processes are crucial for preventing nutrient pollution and eutrophication in water bodies,” he noted. 

Underutilisation of treated sewage water

Thierry Froment, Chief Executive Officer at Veolia Water Technologies Middle East, highlighted the unique water situation in the country. “The UAE is one of the most water-scarce countries globally, with a rapidly growing population. This necessitates a delicate balance between water supply and demand. As a result, the country has increasingly turned to desalination as the primary source of water. Although energy intensive, in the last five decades, desalination technology has developed significantly and the energy efficiency has improved by 80 per cent.” Furthermore, efforts have been made to decouple desalination plants from power plants, enabling the use of renewable energy sources like solar power for the desalination process.

He underscored the underutilisation of treated sewage water. “A large quantity of treated sewage water is discharged into the sea. Less than 50% of the Treated Sewage Effluent (TSE) is being reused,” Froment said. Treated wastewater in the UAE is being used for irrigation, landscaping, street cleaning, boiler feed water and cooling tower feed, industrial applications, and more. Treated Sewage Effluent polishing plants help achieve water quality suitable for these purposes.

Wastewater treatment complexity

Speaking about the challenges, Froment said, “Wastewater treatment faces regulatory challenges, particularly in defining the water quality required for different uses. In most countries in Europe, drinking water quality was requested for all reuse applications, and it is only in the recent years where climate change has reduced the availability of freshwater that European countries have started setting specifications for reuse water more appropriate for the reuse water application. Using drinking water for landscaping or washing the streets of a city is clearly not optimised. The UAE have defined varying water specifications based on specific uses but still a very large quantity of TSE ends up in the sea where it needs to be desalinated again at a much higher energy cost than if further treated to be used in landscaping or irrigation.

Industrial wastewater poses additional challenges due to its variability. Industrial processes generate highly variable effluents, and wastewater treatment plants must be flexible to accommodate these fluctuations. Municipal wastewater also experiences some variation, for example during rainfall, but it requires far less flexibility than Industrial wastewater and this is why there are still many examples of industrial wastewater treatment plants that are not performing well in the UAE because the designers did not take sufficient account of the variability of the effluent, he noted.

He also spoke about the difficulty of transporting Treated Sewage Water to locations where it can be used effectively. “Large sewage treatment plants are often located far from areas where the treated sewage could be reused, increasing the need for extensive piping systems.” To address this, Veolia has introduced package sewage treatment plants of various sizes to reduce piping requirements and enable localised sewage treatment and reuse of the treated sewage, Froment noted.

Uses of treated wastewater

Beyond landscaping and irrigation, treated wastewater can be reused for various purposes. Examples include dairy farms in Qatar, where treated wastewater is used for flushing or spraying cows during hot summer months. The concept of zero liquid discharge (ZLD) or Near ZLD is gaining traction, Froment noted, explaining, “The wastewater is recycled, and only the final concentrate is disposed of, presenting an innovative approach to sustainable wastewater management" as long as there is a site to dispose of this final concentrate in the country like is the case in Dubai with the Dubai Municipality hazardous waste facility of Jebel Ali where the treatment plant was built by Veolia and is operated by Veolia.

Technological innovations

According to Froment, “It is possible to treat any kind of wastewater to the suitable quality for this water to be reused. We have all the technologies in house to do so in Veolia, it is just a question of capital expenditure (CapEx) and operating costs (OpEx) ".  He cited the example of a sewage treatment plant in Namibia operated by Veolia, where the wastewater is treated to be reused as potable water.

One of the driving forces behind advancements in wastewater treatment technology has been  the pursuit of cost-efficiency. Many of these technologies aim to reduce both CapEx and OpEx associated with treatment plants. One such technology is the Moving Bed Biofilm Reactor (MBBR), which allows for the treatment plant to fit into much smaller space and reduce the size (and therefore the cost) of concrete tanks. “Another noteworthy innovation coming from a Veolia subsidiary in Sweden called Hydrotech, is disc filters that are used for the tertiary treatment of the sewage. This has been widely used in the region. These filters effectively remove contaminants from water, contributing to cleaner water resources and enabling the reuse of the treated sewage for irrigation or landscaping. Additionally, compact MBBR package plants are being installed. These enable treating and reusing sewage water locally within communities.” 

A significant development in membrane technology is the MBR (Membrane Bio Reactor), which  employs membranes in the sewage treatment process, resulting in fully treated water that can be directly reused in various applications.

Evaporator

Zero liquid discharge (ZLD) has become a key objective in wastewater treatment. An important part of this system is the evaporator. “After the wastewater goes through membrane treatment, an evaporator is often employed to further concentrate the brine, ensuring that nearly all the water is extracted. The resulting brine or even solids can then be disposed of responsibly, maximising water recovery.”

Veolia's commitment to digitalization and smart technologies was highlighted by Froment. He said all Veolia plants are connected, offering varying levels of digitalisation under the denomination of Hubgrade to optimise plant performance. These digital systems enable operators to monitor and control plants more efficiently and go all the way to creating a digital twin of the treatment plant so that the treatment process is constantly optimised to both the flow and the quality of the wastewater to be treated, thus minimising electrical and chemical consumption . Additionally, smart membrane digital technology is utilised for seawater desalination, optimising maintenance and reducing operating costs.

Future innovations

Froment predicted that in the future there would be a greater focus on sustainability and in particular energy efficiency. “Recovering and utilising biogas from treatment processes is expected to become more prevalent. These innovations will play a pivotal role in the UAE's journey towards sustainability in water management.”

Froment welcomed the move to prioritise water in the COP28 agenda. “In countries like Israel, where 85 per cent of wastewater is reused, it serves as a shining example of effective water resource management. The UAE, Saudi Arabia, and Qatar have set ambitious goals to reach similar or higher levels of wastewater reuse, signifying their commitment to sustainable water practices.” By leveraging its resources and expertise, the UAE can lead the way in developing and implementing sustainable water treatment technologies that can then be used in the other water scarce regions of the world, he said.

Industrial applications

Peter Lembrechts, General Manager, BESIX Middle East, said, “There’s a perception that wastewater reuse must be limited to green spaces. BESIX’s approach emphasises the primary use of high-quality treated water for industrial applications, with irrigation and landscaping being secondary considerations.  Industrial sectors find significant utility in repurposing treated wastewater.” 

Effective wastewater treatment and strict adherence to quality and safety standards are foundational to these diverse industrial applications, he said adding, “Recycled water is valuable for various industrial processes such as manufacturing, chemicals, and metals production. In the maritime sector, clients often prefer recycled water for ships and barges due to its consistent and standardized quality. Cement factories find recycled water indispensable due to its low conductivity and appropriate pH, aiding in the maintenance of lower raw material feed temperatures. Ready-mix and block manufacturing industries rely on low salinity recycled water to ensure the production of high-quality concrete. District cooling plants heavily rely on recycled water due to its low Total Dissolved Solids (TDS) and chlorides, allowing for a higher number of water cycles. Car wash companies choose recycled water to prevent car colour damage caused by contaminated, salty, or high TDS water. Construction sites benefit from using recycled water to safeguard buildings from soil salinity, a potential risk posed by groundwater with high TDS that could harm basements. Asphalt plants find value in utilising recycled water to create desirable asphalt emulsion, effectively reducing production costs.

"BESIX is a pioneer in the field of water reuse in the UAE. Our projects place the environment and the community at the forefront. There is extensive potential in recycled water to conserve resources and enhance operational efficiency across a wide spectrum of industries. Our water management projects deliver efficient, innovative, and adaptable solutions that contribute to a circular economy and a more sustainable water future, " said Lembrechts. 

Lembrechts noted that BESIX's projects, including SAFI, Qatra Water Solutions, the Ajman Wastewater Treatment Plant, and ISTP2, underscore the company’s commitment to addressing water challenges in the community. These initiatives not only prioritize water sustainability but also contribute to reducing environmental risks and promoting eco-friendly practices, he said. 

SAFI, established in the Emirate of Ajman, is the first plant in the region that brings the concept of commercialized “water reuse” fully into practice. SAFI reuses tertiary treated wastewater from the Ajman Sewage Treatment Plant, that is polished through Micro Filtration and Reverse Osmosis processes. The plant has currently a production capacity of 1.8 million USG (6,800 m3) per day.  Qatra Water Solutions, a joint venture with Shurooq, produces high-quality water suitable for industrial or irrigation uses, as well as dewatered sludge. The wastewater treated at the Ajman Wastewater Treatment Plant can be reused. 40 per cent of it is used for unrestricted irrigation of all of Ajman's landscape and greenery; 10 per cent is treated to an even higher standard by SAFI and used for commercial and industrial applications. The Al Wathba 2 Plant treats a significant part of the wastewater coming from the city of Abu Dhabi, while the Allahamah Plant treats a significant part of wastewater coming from the city of Al Ain.  

“Our mission is to excel at creating sustainable solutions for a better world, and a key aspect of this is our emphasis on the effective recycling of resources,” Lembrechts noted.