"Desalination is becoming the most sought-after technology to provide potable water and solve the water shortage problem"

Alan Mokbel
General Director, Grupo Akvotek, SA de CV

BNamericas: Why is using ultrafiltration technology more efficient than conventional wastewater treatment?

Mokbel: If we take the example of a sedimentation tank (or clarifier), this requires a very high residence time in order to allow the contaminants to coagulate and precipitate at the bottom of the tank. Ultrafiltration, on the other hand, does not require any residence time. We don't need to wait for the pollutants to coagulate, as the membrane takes care of separating them. So it's a lot more efficient because the process is continuous and it doesn't require a lot of space. This type of equipment is modular, so if a client needs a greater capacity, we simply need to add more modules without the necesity of more civil works. The equipment can be adjusted to treat a certain amount in a first stage, with the ability to treat a greater amount in the future.

For example, if we need to double the capacity, it's very easy to install a second unit, without the need for heavy construction. If we use conventional plants for potable water treatment, for example, if we wanted to double the capacity we would have to build an entire new plant. So you have to spend money on the civil construction work, and you need more space to deal with that additional capacity.

BNamericas: What are the company's plans for 2010?

Mokbel: We're working to develop projects with other hotels, and we are also looking to enter the industrial market. We are also developing a greywater system for residencial applications. We're working with different industries at the moment to see what opportunities there are to improve their wastewater treatment plants, and reduce their operational and energy costs, as well as the potential for water reuse.

BNamericas: In which particular industries do you see a potential for greywater reuse?

Mokbel: For greywater recycling, the main industry we are expecting an increase in interest is the hotel industry as well as commercial complexes, such shopping malls, office and apartment buildings and small to medium residencial developments.

BNamericas: Have you seen an increased need for water reuse given the shortages affecting Mexico at the moment?

Mokbel: I think every industry is now seeing a greater need to reuse water, because of the crisis that's affecting Mexico at the moment, particularly Mexico City, where there is no longer sufficient fresh water available for human consumption. So there's a lot of interest in ways to recycle and recuperate water, because the cost of water per cubic meter is going to increase. Small industry in particular is looking for ways to reuse water in order to cut costs.

BNamericas: Is there high demand for desalination plants in Mexico?

Mokbel: Most of the time it is hotels that operate this type of plant, especially those near beaches and resorts. There are a lot of hotels in Cancún and Acapulco that are now using this technology, although we as a company have not had the chance to provide it in Mexico yet.

BNamericas: Why is desalination particularly convenient for hotels?

Mokbel: It's a lot more convenient to install a plant in a hotel, because the cost of operation is always much lower than the cost of the municipal potable water supply. Obviously the cost of investment is higher, but the investment recovery time is quite short. And once you've installed one of these plants, you no longer depend on the municipality for your water supply.

It often happens that the municipal water supply runs out, or there are cuts, so hotels that depend on municipal water supplies have to use methods such as private water suppliers to meet their needs. Hotels that have their own desalination plants are not affected by the shortage.

BNamericas: Do you see desalination as a possible solution to the region's water shortage?

Mokbel: In Mexico City we're very much inland - so the infrastructure necessary to bring water from a desalination plant to the city is very expensive.

But yes, I think desalination is already becoming the most sought-after technology to provide potable water and solve the water shortage problem.

BNamericas: Can you see any other possible solution to the shortage?

Mokbel: I think it's important to recycle as much water as possible. If we recycle water, we reduce the demand for potable water that is taken from nature. And if we reduce the demand for potable water, we give nature the possibility to recover, so that underground water sources can be refilled, so all the natural processes can begin again and more or less resume their natural cycle.

I think one of the keys, apart from desalination, is finding ways to treat wastewater to make it potable. It's already possible, but it's expensive, and more research is still required. For example, MBRs [Membrane Bioreactors] already produce very clean water. It's not potable, but it is of a quality that could be treated to make it potable.

I think if we can see more industries, and even towns and homes, start to invest more money in recycling wastewater to use for irrigation, or any secondary water use, and using potable water only for drinking or cooking, then we'll be making good progress.

by Catherine Setterfield

Article published in BNamericas.com on the 10th of December, 2009 [article link ]
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