According to the United Nations, the industry and energy sectors together account for 2 per cent of global water demand. Balancing the requirements of sustainability against industrial mass production requires a number of dedicated solutions to ensure that water is managed efficiently and equitably. For companies such as Emirates Global Aluminium (EGA), which has a combined annual production capacity of 2.4 million tonnes per annum placing EGA among the top five primary aluminium producers in the world by volume, the business accepts its responsibility to protect the well-being of the environment via the adoption of sustainable water management systems and capabilities. 

It is with this in mind that environment performances at EGA’s operating assets in the UAE – Dubai Aluminium (Dubal, also known as Jebel Ali Operations) and Emirates Aluminium (Emal, also known as Al Taweelah Operations) – are monitored closely to ensure compliance. 

“Everything we do is in line with sustainable practices and EGA continually strives to exceed international standards,” says Salman Abdulla, executive vice-president for health, safety, sustainability, environment and quality. 

“Our overriding aim is to minimise the impact of our operations on the environment and our water management systems play a crucial role in this process. The latter embraces diverse aspects, such as water generation, water consumption, water treatment and recycling.”

WATER GENERATION 

Abdulla: continuous striving to exceed international standards

Both of EGA’s UAE sites operate seawater desalination plants, which generate the fresh water required to meet the on-site operations’ needs. Al Taweelah Operations Desalination Plant operates reverse osmosis technology and can produce up to 3.75 million imperial gallons (17,000 cu m) of fresh water per day, complemented by an 18 million imperial gallon reservoir. 

Jebel Ali Operations Desalination Plant produces fresh water by thermal distillation, using waste steam exhausted from two free-energy driven back pressure steam turbines, and can produce up to 30 million imperial gallons (136,000 cu m) of fresh water per day, complemented by a 10 million imperial gallon reservoir.  The desalination process at Jebel Ali Operations utilises six Multi-stage Flash (MSF) evaporators where the seawater/brine is heated, placed into a vacuum, and cooled. The distilled water produced in the process is then pumped to a blending plant where appropriate additives make it potable. Finally, the blended water is stored in a reservoir from where it is pumped to customers. The brine discharge is cooled, filtered and rigorously tested before being returned to the sea. 

Most of the distilled water produced is used for industrial applications within Jebel Ali Operations and the majority of the potable water is sold to external consumers through the dedicated Jebel Ali Operations Water Filling Station or supplied to adjacent industries through a series of pipelines. Water is also supplied free-of-charge as required by the emergency and fire services in and around the Jebel Ali area.

Importantly, the quality of potable water produced by Jebel Ali Operations Desalination Plant complies both with the Dubai Municipality’s standards and the drinking water quality guidelines published by the World Health Organization (WHO).  Moreover,  Jebel Ali Operations Desalination Plant identified and implemented an alternative water disinfection method using chlorine dioxide which has consequently reduced the bromate level in the product water to less than 3 ppb (below detectable level). “Ours was the first seawater thermal desalination plant in the world to adopt this method of disinfection,” Abdulla says.

USE AND CONSERVATION 

EGA continually looks for ways to reduce its water consumption and recycle water wherever possible. In some of the operations’ production processes, for instance, water is reused in a closed-looped system to cool machinery and production lines to optimise consumption. A number of measures have also been implemented to prevent increases in water consumption – such as the installation of additional flow meters at Jebel Ali Operations Desalination Plant to better manage water consumption by allowing EGA to report actual (rather than estimated) consumption. 

In terms of water recycling, Jebel Ali Operations Water Filling Station has been re-engineered to capture spilled water; and improvements to the on-site Sewerage Treatment Plant (STP) effectively eliminated Jebel Ali Operation’s reliance on potable water for irrigation purposes.

Like any other well-established environmental sensitive industrial corporation, nearly every aspect of EGA’s operations is subject to environmental regulations passed by the regulatory authorities in Dubai and Abu Dhabi. “We obtain environmental permits for water discharge from the regulatory authorities on an annual basis; and operate well within the permitted limits,” says Abdulla.

He adds that, in 2009, Jebel Ali Operations implemented an online system for discharge monitoring and continues to monitor site effluents, and utilise independent technical expertise to ensure that its operations have the least possible impact on the environment. “Jebel Ali Operations has also installed a real-time, marine monitoring system, which allows us to monitor early indicators of red tides and notify local authorities. We are also considering additional measures to protect the Jebel Ali Operations intake systems,” he says.

In addition, Jebel Ali Operations introduced new guidelines for conserving marine life in May 2011, which included specific procedures for rescuing endangered marine turtles trapped accidentally at the site’s power and desalination stilling-chambers. The guidelines include a requirement to conduct site inspections at the start of every day shift and step-by-step instructions on how to rescue and rehabilitate trapped turtles. 

WASTEWATER TREATMENT

EGA-Al Taweelah Operations utilises the reverse osmosis technology for desalinating water

All of the waste from EGA’s core operating assets’ waste streams is recycled, disposed of or treated on-site. Both Jebel Ali Operations and Al Taweelah Operations own and operate on-site STPs, where all the liquid waste is treated on-site, sludge residue is used as a fertiliser, treated water is used for irrigation purposes and sweet water is sold in bulk. 

“Wastewater sewage treatment at our STPs includes a combination of physical, chemical and biological treatments to remove contaminants from wastewater to produce liquid and solids suitable for discharge to the environment or for reuse,” explains Abdulla. “Moving Bed Biofilm Reactor (MBBR) technology has become a mainstream technology among the various biological treatment systems in wastewater recycling where a larger effluent volume is involved.”

Jebel Ali Operations STP, commissioned in 1979, has virtually achieved zero waste to landfill status. All treated water is used for irrigation purposes on the site; while the sludge residue is used for composting purposes. Jebel Ali Operations also has its own hazardous liquid waste treatment facility, with zero hazardous liquid waste being disposed of via the Dubai Municipality treatment plant. 

Al Taweelah Operations STP was commissioned in 2009 and is designed to accept dry weather flow of 700 cu m/day and wet weather flow of 840 cu m/day. The plant was expanded in 2014 by adding an additional equalisation tank of 350 cu m to equalise the original treated water capacity. The utility consists of primary, secondary and tertiary treatment processes to remove or reduce contaminants to acceptable levels including fine grit screening, biological and chemical treatment, and sand filtration. 

Current reuse practices for treated water and biosolids at Al Taweelah Operations are in line with the UAE Government philosophy of reusing water to the maximum extent possible. Treated sewage water is stored in a 700 cu m storage tank with continuous ultra-violet (UV) disinfection; and the reuse system installed on the site includes an automated timer-based irrigation pumping station to irrigate the landscaped areas. 

The biosolids are further treated by centrifuge to extract the residual water, then collected and stored in a designated waste collection skip as ‘sludge cake’ which is transported out of Al Taweelah Operations for recycling at an off-site Abu Dhabi Municipality compost plant. 

“Al Taweelah Operations has established an STP Safety Plan to ensure compliance with the licence conditions of Abu Dhabi Regulation and Supervision Bureau (RSB),” Abdulla adds. “The plan includes a detailed assessment of the wastewater management system; and also identifies the controls and monitoring necessary to produce recycled water and biosolids of an appropriate quality for the proposed end uses.”