By Ed Attwood
The Middle East’s water supply depends heavily on the issue of wastewater reuse.
The Middle East’s water supply depends heavily on the issue of wastewater reuse.
At a break-out session held during Frost & Sullivan’s recent Growth, Innovation and Leadership (GIL) Conference held in Abu Dhabi in September, senior figures from the region’s water industry were asked to list the most important issues that were currently prevalent in the wastewater sector.
The experts – from industry giants such as Metito, Concorde-Corodex Group and Aquatech – were split into four groups, with each group suggesting three key themes of interest to the sector.
Naturally, a few of these topics came up more than once. At the top of list came the need to improve the reuse of wastewater, with some companies campaigning for wider use of treated sewage effluent (TSE) and a call for more effort on the sludge-to-energy front. Also mentioned was the need for better strategy planning for larger developments, and the upgrade of existing plant.
It comes as no surprise that the issue of private financing was also brought up, especially in the tough operating environment that the industry is currently facing. Lastly, there was also a call to improve the GCC’s strategic storage of water, which in most cases is just two days, in comparison to, say, 21 days in South Africa.
“On the whole, the Middle East is expected to spend about US $100-120 billion over the next 10 years on water and wastewater investments to counter the severity of water scarcity,” says John Raspin, partner and director at Frost & Sullivan’s Energy & Environment, Europe, Middle East & Africa practice.
“But traditionally, due to societal perceptions, wastewater reuse has not been embraced well in the GCC countries,” Raspin adds. “In recent years, increased water demand for landscaping, district cooling, construction activities and concerns about environmental degradation have made a strong case in favour of wastewater reuse. However, the amount to which the potential of this economically-attractive option is exploited remains to be seen.”
Raspin’s view is one that was also espoused by the keynote speaker at October’s Saudi Water & Power Forum, who told a host of senior figures in Jeddah that the region needed to reuse its water more efficiently. “I come from London, where all the water we drink has passed through numerous human bodies in every town along the River Thames before it reaches my tap,” said Fred Pearce, a scientific journalist and author. “At each town, it is abstracted, drunk, excreted, collected, cleaned up and put back into the river - it is safe, I assure you.”
So how can this revolution in the recycling of wastewater realistically come about? John Ord, MWH Global’s principal process engineer, based in the UK, says that the way that contracts are awarded to companies should be revamped to better understand the needs of water reuse. “The procurement route typically adopted in the region follows the design and build path for desalination, wastewater treatment and re-use projects, including advanced re-use,” Ord explains. “To optimise the water/wastewater balance at both the design and operational stages, you could defer the installation of the advanced re-use section of a re-use installation until after the wastewater treatment plant becomes operational.”
Ord says that the reuse demands for both irrigation and advance re-use quality water would be potentially better comprehended as a result. “This, in combination with the ability to trial Reverse Osmosis systems on waste streams, would provide the opportunity to both tailor treatment flows and qualities to actual demands, while also allowing the process to be configured to treat the specific wastewater generated,” he adds.
However, a key factor in the success of these suggestions would undoubtedly be cost. It is crucial that any additional elements in the contract-award process do not lead to extra investment. The same is true for government regulation. “In order to encourage treated wastewater recycling, appropriate, justified and necessary regulation is required that does not introduce significant and weighty investment for compliance monitoring,” explains Magdalena Hijaz, process engineer for local engineering firm Eagle Electromechanical LLC. “Consultants and contractors need to be able to share their experiences of appropriate technological solutions with local authorities for a better understanding of what can be achieved to safeguard the environment and, crucially, public health.”
The sludge-to-energy issue is certainly one that is of interest to regional executives. As MWH looks to find ways of recycling sludge from its plants – such as the planned reuse of sludge as fertiliser at its Jebel Ali plant – it has been keen to access the opinions of its competitors, and recently hosted a biosolids round table discussion to explore the options for sludge treatment and reuse in the region.
This concept appears to have considerable mileage in the Middle East, especially as the lack of landfill space will continue to create headaches. And despite the sludge-to-fertiliser scheme being implemented in Jebel Ali, such alternative outlets for reuse in agriculture and landscaping appear to be limited.
“A general trend in the studies that we conducted was that some form of co-treatment of sludge and municipal solid waste offers a range of benefits,” says Marcel Goemans, supervisor at MWH’s solid waste division. “Both co-combustion of (solar- or thermal-dried) sludge and MSW in an Energy-from-Waste plant and co-digestion of sludge cake and organic municipal solid waste or food waste from hotels and restaurants are feasible technologies to consider.”
With the Middle East’s first large Energy-from-Waste plant (the Qatar Integrated Waste Management Facility near Doha) approaching completion, Goemans says that the issue of sludge co-incineration with municipal solids waste, as opposed to mono-incineration, can result in a minimal additional cost if this is included in the initial design. “Mono-combustion of sludge cake or solar-dried sludge should not be ruled out, however,” observes the MWH executive. “This option still offers the advantage of being independent from the waste sector, providing a dedicated solution to handle sludge.”
But some players in the wastewater segment will inevitably be discouraged from the sludge-to-energy option, simply due to the economies of scale involved. “There are numerous ways in which biosolids can be processed which are determined by the end application (quality) which in turn is influenced by public acceptance, economics and market trends,” explains Eagle’s Hijaz. “Medium-to-small-scale sewage treatment plants that we deal with do not produce enough of this by-product to justify the investment in a waste-to energy facility. A large centralised system is a solution that is environmentally and socio-economically viable.”
The challenge for the local authorities is to carefully look into areas where water reuse can be applicable. “In the UAE, specifically, the greatest challenge has been aligned with the expansion of the portfolio for effluent reuse,” says Eagle’s Hijaz. “We are liaising with local authorities, who are currently reshaping their guidelines, to diversify the reuse areas which were previously inaccessible. These include industrial re-use applications and non-potable urban uses, e.g. in fountains, lakes etc, amongst others.”
While some projects, such as that being constructed at Al Wathba in Abu Dhabi, are treating wastewater to irrigation quality for reuse, the question is being asked whether that is entirely viable. “Water treated to irrigation quality will not be directly suitable for use in many water reuse applications and restricts the reuse opportunities to use in irrigation only,” explains Robert Garner, lead design engineer at MWH. “The question to raise therefore is whether treating wastewater to irrigation quality is the most ‘sustainable’ and valuable use of the treated water and whether we should be promoting schemes whereby non-native planting of roadsides and parks is consuming huge volumes of treated wastewater.”
One train of thought suggests that reused wastewater would be better utilised to accomplish reductions in potable water consumption, which requires a large amount of energy and generates large volumes of brine with chemical contaminates back into the sea. The requirement to use treated effluent for district cooling plants gives an immediate need to address the quality issues for treating effluent but also raises challenges in the handling of the reject from polishing plants and the blowdown from cooling schemes.
All of this amounts to some stiff decision-making for the local water authorities in the GCC. About the only issue that can be confirmed with certainty is that wastewater, despite its name, is far too valuable a resource to be thrown away. Of course, with financing becoming more of an issue in the current climate, the investment required to change regulations must also be kept to a minimum.
Surely at this stage, however, the strategy must be to focus on long-term planning. “By designing water infrastructure (specifically infrastructure to support non- potable water requirements) so that it could, in the future be segregated from the drinking water network, the potential to minimise the use of seawater desalinated water and maximise the re-use of wastewater can be realised,” indicates Ord. “While current irrigation requirements may consume all the available final effluent produced by a specific site, future wastewater treatment plant expansions may result in the production of excess effluent and at this point the advanced re-use system could be installed.”
Advanced re-use through RO technology could potentially reduce power demands – another key element in the electricity-hungry GCC – as well as increasing overall system sustainability. By preparing for its use within the network system at the design stage the advanced re-use system can be installed as and when it becomes financially and technically viable.
“We cannot be a wasteful society in terms of letting this valuable resource slip through our fingers and on the other end of the spectrum we should not be over-designing treatment systems,” says Eagle’s Hijaz.
As demand for water increases, the demand for advanced reuse systems will continue, which, in an ideal world, should enable the region to benefit from a balanced desalination and advanced effluent reuse network.