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Water ways

Water transmission systems in the Middle East are expanding.

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Sudhir Kumar, engineering group manager at MWH.
Sudhir Kumar, engineering group manager at MWH.
Richard Zambuni,  Bentley.
Richard Zambuni, Bentley.
Eonomics still favour large scale plants as opposed to decentralised wastewater treatment options.
Eonomics still favour large scale plants as opposed to decentralised wastewater treatment options.

Water transmission systems in the Middle East are expanding at a rapid pace, which means good business and not a few challenges for the companies responsible for designing and engineering them.

Water not only sustains life, it also fuels growth. In a region experiencing rapid population growth as well as increasing urbanisation and industrialisation, business in building and upgrading water transmission system is brisk. The Middle East is thus a growth area for companies that model and design such systems.

“The Middle East is extremely important to us, its one of the fastest growing, if not the fastest growing part of our water business,” says Richard Zambuni, global marketing director, geospatial, at Bentley.

“And the reason the Middle East is so important is for a syndrome of issues: you’ve got very fast population growth, and the population is nearly all in densely populated cities. The infrastructure is being built, in most cases, it doesn’t pre-exist. Its being built now to service these growing populations.”

On top of building new infrastructure comes the need to replace ageing existing water transmission systems. Small wonder then that Bentley have recorded impressive growth figures over the last four years, with compounded growth of around 25 percent in the Middle East and Africa.

MWH, one of the other big players in wet infrastructure design and engineering, are similarly committed to the region. Last year, the company made the Middle East region one of its four distinct geographic business areas, alongside Europe, the Americas and Asia.

“Recent development shows how important the regional market is to MWH,” says Sudhir Kumar, principal civil engineer and engineering group manager at MWH in Dubai.

Desalination to destination
One of the determining factors of water transmission in the region is the heavy reliance on desalination to produce potable water. This means that drinking water often has to travel long distances before it arrives at cities and developments located inland.

Zambuni points out that most big cities in the region are either costal, or can otherwise be supplied by river water. Nevertheless, this does not apply for all major urban centres.

Delivering desalinated water to places that are both far from the sea and high in elevation, such as Al Ain, Riyadh and Harare is expensive, says Kumar.

“After being desalinated at Jubail and Ras Alzaur in Saudi Arabia, water is pumped over 400 kilometers inland through a number of pipelines to the capital city of Riyadh making it one of the most expensive water supply schemes.”

Long distance water conveyance necessitates careful planning, taking into account issues such as security of supply, water age, risk of contamination and water disinfection requirements. To this must be added higher capital, operation and maintenance costs.

At a loss
The key challenge for water distribution worldwide is minimising the amount of water lost in transit. While water loss might be associated with burst water mains flooding roads by the general public, the real damage is done by small leaks and creaks in piping and joints. Losses can range from 10 percent to up to 60 percent.

The reasons for this loss can be manifold. Materials are a common culprit, especially if age comes into play. “In older systems you’ve got things like cast iron pipes. Cast pipes typically fracture at some point, and they are subject to catastrophic failure more than plastic piping.

Where you’ve got cast iron pumps and joints that have degraded over decades, that’s when you get the more serious problems,” explains Zambuni. In densely populated areas, this problem is exacerbated by the fact that utilities tend to pump water through the system at a higher pressure.

This pressure then forces more water through leaks, increasing the water loss.

“What you need to do is model the demand curves, model the pressure curves, make sure you’ve got the right sized pipes, valves, make sure the network is constructed in the right way to not stress it at any point. So the pressure you’re using in the network is as even as possible,” says Zambuni.

What else can be done to keep water loss to a minimum? “The old saying ‘prevention is better than cure’ is equally applicable to water supply systems” says Kumar. “Proper planning, design and high quality construction is the first step in minimising water leaks and wastages.”

“There are a number of factors, from planning and design to the operation and maintenance stage that affects the system efficiency,” he continues.

“Correct hydraulic design parameters and suitable pipe material selection are some of the key parameters during planning and design stage that can severely affect the distribution system if not selected appropriately.”

Equally, appropriate construction methodology and procedures are important.

“Pipe bedding, soil compacting, pipe jointing, thrust restraints at bends, flexible joints near structures are some of the key features that require strict quality control during project execution to avoid premature failure of the network.

We have witnessed a number of water networks that experienced multiple failures during commissioning due to poor construction,” says Kumar.

Zambuni believes that utilities in the Middle East have yet to recognise the importance of some of those aspects, with design and construction seen as more important than looking to optimize the operation of the system once its operational.

“At the moment the focus is on building and designing good networks, and getting the infrastructure in the ground, and less on operational optimisiation, as there is in Europe and the US. That hasn’t come yet, but its just a matter of time.”

Wastewater – stay big, go small?
Given the cost of transmission systems, and the fact that human settlement in the Middle East can be sparse and intermittent, there have been calls for a greater decentralisation of wastewater plants.

This would entail both a scaling down of wastewater processing plants and of water transmission networks.

Both options have their cost advantages. Large, centralised plants are low in production cost, yet high in transmission cost, while the opposite is true for decentralised plants.

As the experts point out, a decision on the size of the plant should be taken on the basis of every individual case.

“There is no fit for all solutions and each case should be techno-economically evaluated considering key factors such as project catchments, topography, total demand, ground condition and other design requirements,” says Kumar.

But centralisation is the better option in most cases, thinks Zambubi: “Plants are expensive to build and operate, typically you have relatively few wastewater plants because they are expensive pieces of kit to put together. So its still cheaper to have quite a lot of pumping than to have a lot of wastewater plants.”

Zambuni points also to the increasing trend towards green solutions, which is evident especially in power generation, where decentralised small-scale plants contribute to electricity production.

Likewise, ecologically friendly wastewater treatment plants are starting to come to the market.

He feels that the time is not right for those solutions from a cost perspective: “Water is different from other utilities, such as distributed power generation through biomass, for instance. With wastewater, the economics point to larger plants in smaller numbers still.”

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