Desalination: The future of water?

A pioneer in tapping saltwater for household use may yet provide a viable option for mitigating Metro Manila’s water woes.

IMAGINE this. An almost limitless supply of water for Metro Manila’s 14-million-plus population with spare to boot for our city gardens, nearby farms and swimming pools.

The proposal to introduce water desalination to supply Metro Manila’s growing need for the previous commodity cropped up at the height of a severe water crisis that plagued the Metro cities last summer.

But there’s a catch. We may have to spend much more to enjoy the luxury of water abundance with the desalination option.

Rain dance

INFREQUENT monsoon rains over the past few days have started to increase the water level at Angat Dam, inching slightly above the critical level but still below the normal operating level.

As of 6 a.m. Tuesday, water at Angat was 161.56 meters—a good sign that the water shortage problem may soon come to pass.  While it is now above the critical level of 160 meters, it is still way below the 180-meter normal operating level, which means residents of Metro Manila, with a population of over 12 million, will continue to experience severe water shortage. More rains and water at Angat may soon reach normal operating level. The question is, how much longer?

Severe supply shortage

The bay area in Cebu. The province is now a leading consumer of desalinated water.

THE supply shortage this year is the worst the National Capital Region (NCR) has experienced in recent years.  First felt in the East Zone—the concession area of Manila Water Co. Inc. with about 6.8 million customers last March 6—the water supply shortage started to affect the close to 9 million customers of Maynilad Water Services Inc., which covers the West Zone Concession Area last month.

Both companies were compelled to implement rotational water service interruption despite partially sourcing water from Laguna de Bay and deep wells, as the National Water Resources Board (NWRB) reduced water supply allocation coming from Angat.

Because of the water supply shortage, concerned government officials have called on the public to conserve water and suggested rainwater harvesting for non-essential water uses to reduce the demand for clean water coming from Angat Dam.

Solutions, solutions, solutions

WHILE the Duterte administration, through the Metropolitan Waterworks and Sewerage System (MWSS), is developing various short-, medium- and long-term water source projects that can boost potable water supply for the ever-growing population in Metro Manila, the provision of water using an assortment of water-treatment technologies—for domestic, commercial and industrial uses—is gaining traction. One such technology, desalination, is becoming the buzzword.

One company is pitching the call for the adoption of desalination technology and tapping the country’s unlimited supply of this precious economic resource from the ocean to provide adequate fresh water.

Through desalination, a process that takes away mineral components from saline or saltwater, the provision of fresh water, possibly tap or clean drinking water, however, is very expensive; hence also a lucrative undertaking.

It entails the use of more energy, the steady supply of which remains a big challenge for the Philippines.

Extremes:  Supply shortage, excessive rainfall

ARTURO TAHUP, associate for low carbon communities of the Institute for Climate and Sustainable Cities (ICSC), said cities will always have to grapple with how to meet their water needs.

“In the case of Metro Manila, we are facing both extremes—people do not have enough water flowing into their faucets, yet an hour’s worth of continuous rain will cause flooding.”

According to Tahup, beyond securing the limited supply of fresh water, people need to improve the management of demand.

“Water usually flows out of the faucet then goes directly to the drains and ends up in sewerage, untreated—this illustrates not only the gravity of our wastewater problem but also an opportunity to improve our management of demand,” he said.

Expensive, unaffordable—DENR exec

FOR the Department of Environment and Natural Resources (DENR), while the technology is already available, desalination is something that needs further study.

Undersecretary Benny Antiporda, deputy spokesman of DENR Secretary Roy A. Cimatu, said the cost of producing desalinated water will be burdensome to consumers who would surely shoulder the cost of production.

“Desalination means money. It requires a huge amount of money. You will only make the people of the Philippines poorer because it is expensive,” said Antiporda, also DENR’s undersecretary for solid waste management and local government unit concerns.

Instead of pushing for desalination, Antiporda said he is keen on rainwater harvesting to mitigate the effect of water supply shortage and, at the same time, put in place a flood-control measure that has become a perennial problem in low-lying areas.

“What we need is to build water-impounding facilities in vacant areas to harvest rainwater,” he said.

For instance, Antiporda said spaces like road crossings can be developed for water impounding underneath these.

“By harvesting rainwater, we’ll reduce the pressure on Angat and we’ll have plenty of water to use,” he said.

‘Ripe for the taking’

SOUGHT for comment, Engr. Antonio Tompar, president and chief executive officer of Mactan Rock Industries Inc., a pioneer in desalination, said that the technological advance in water treatment through desalination is already ripe and may yet provide a lasting solution to the perennial water shortage in Metro Manila and other parts of the country.

Cebu, a province facing severe shortages in the future, is now a leading consumer of desalinated water, Tompar said.

The Mandaue, Cebu-based firm is one of the leading water-technology solution providers in the country.

Its biggest water system is a 22,000-cubic-meter per day (CMD) seawater facility in South Road Properties in Cebu City that supplies SM Seaside and City de Mari of Filinvest.

The company offers “build, own, operate and manage,” or BOOM, scheme to institutions or private and exclusive subdivisions, or “bulk water” supply to water districts.

Gaining traction

TOMPAR said desalination is gaining traction not only Cebu but in other areas where water scarcity or supply shortage is a problem, citing three big projects lined up in Manila.

“I have more projects now in desalination,” he said.  He confided that when the company started desalination way back 25 years ago, it required around 5 kilowatts of electricity to desalinate 1 cubic meter of seawater.  “Now as a standard, it is half of that, [and] in some cases, less than 2 kilowatts is enough,” he said.

Tompar plans to seek an audience with Energy Secretary Alfonso Cusi to discuss how the cost of desalination can be further reduced.

He said there are power companies that are willing to work with the company “to give power at P6 per cubic meter.”

“I will ask him, through a letter of intent, to bring down the power cost,” he said.

Tompar noted the Philippines is surrounded by seawater and there are several hotels, some with shopping malls along bay areas like those in Cebu, that are already using desalinated water.

In Cebu, he said, groundwater is already contaminated by sewage, thus making desalination very feasible. “Come to think of it, desalination is now very competitive,” he added.

“In Mactan, conservatively, more than half of the water there is desalinated. In the bay area in Cebu, more than 50 percent is desalinated.  In our company alone, we are producing about 30,000 cu. m. of desalinated water,” he said.

‘Brackish’ water desalination

TOMPAR said he is eyeing a project in Metro Manila where the company will turn brackish water, like that from Pasig River, into potable water. The desalination of brackish water will require less power, he said, compared to removing minerals from saltwater.

“One project we would like to do in Metro Manila is brackish water.  It requires only one-half kilowatt per cu. m.,” he said.

That means a lower cost of just P5 per cubic meter because brackish water’s salinity is lower.

According to Tompar, some portions of Laguna de Bay have very low salinity.  “We can already supply water from Laguna de Bay at very low prices,” he said.

Mactan Rock, he added, is manufacturing its own desalination plants, which is why its cost is lower. “We pioneered this 30 years ago.  Right now, we are just importing component parts that are not available in the Philippines [like] membrane, pumps…. But the structure, assembly, pipes and technology, we already have it.  I am building more desalination [units] in the bay area not only in Mactan but in Metro Manila,” Tompar stated.

Industry-wise, he said, some private companies also buy imported equipment but added that, modesty aside, “when it comes to open bidding when there are fair bidding chances for desalinated water supply, we will win.  We are the lowest bidder.”

Less pollution, less cost

ACCORDING to Tompar, government efforts to rehabilitate water bodies are important to reduce the cost of desalination, or any water treatment method, for that matter.

“In Laguna de Bay, Manila Water and Maynilad also have desalination. Sometimes, when the salinity is high, they do desalination,” he said.

Given the opportunity or accessibility, he said water from Pasig River can be extracted by the firm, which will clean it up and put it in desalinated brackish water for industries.

“We are not going to supply it, I will make it potable but I will sell it as nonpotable for flushing CR, cleaning toilets, etc. Hotels now, even in the Philippines, even those coming from MWSS, Maynilad and Manila Water, they don’t declare it as potable. They give bottled water,” he said.

With less pollution, in Laguna de Bay and Pasig River, desalination can provide cheap water, he said. “But water from Manila Bay will cost a little more than brackish.” Nevertheless, he said, because of the need, three more big installations await near the bay, citing the company’s offer for affordable water supply.

“We are cheaper by P10 per cu. m. by industry standard. We don’t extract directly from the sea. We extract seawater from deep water near the sea. There are chemical pollutants but the desalination process cleans it. I have several desalination projects in Manila. Our company’s brackish bulk water costs only about P7.78 per cu. m.,” he said.

Optimizing freshwater resources

ACCORDING to Tahup, desalination is one proposal among a range of options to consider in optimizing existing fresh water resources.

“Water desalination is not new, and technology will continue to improve and become energy- and cost-efficient. However, the country is also currently challenged in securing enough power, which large-scale desalination would require vast amounts of. In the meantime, water conservation, gray-water recycling and rainwater harvesting are already feasible and [are] practical options in urban areas such as Metro Manila,” he said.

Whether or not desalination is a viable option depends on the specific context of each community, he pointed out.

Desalination, works in communities struggling with water scarcity, drought and salinization. However, he said, the cost implication and efficiency, as well as waste management, would need to be factored in should a decision be made to replicate it on a scale such as Metro Manila’s.

“Ultimately, we need to consider: Who will foot the bill for the investment and the extra costs? Will consumers be willing to pay for it? Are they also willing to explore other options that are within their means to address? And do they have access to these options?” he asked.

Image Credits: Siwabud Veerapaisarn | Dreamstime.com, Designua | Dreamstime.com, Alexey Kornylyev | Dreamstime.com



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