Thursday 20 March 2014

Singapore looks to California for lessons on water management

By Monica Kotwani, Channel NewsAsia, 18 Mar 2014

ORANGE COUNTY, California: Singapore's NEWater model of producing drinking water from used water is the result of much learning from California's Orange County Water District, which first started on it in the late 1990s.

Almost two decades on, Singapore's national water agency PUB said it is still relevant to look at the Lee Kuan Yew Water Prize winners for ways on utilising resources in an efficient and sustainable manner.

The Lee Kuan Yew Water Prize recognises individuals or organisations that use ground-breaking technology or innovative policies in solving water problems.

In arid California, it is a four-step process to give Orange County residents drinking water from used household water.

This includes filtering water through tens of thousands of fibre bundles to remove bacteria and other organisms, and exposing it to ultraviolet light for further purification.

This process is the final step in disinfecting and further purifying water.

The treatment process is similar to what PUB does at its NEWater plant to recycle water from households and light industries into drinking water.

But where NEWater is released into reservoirs, the Orange County Water District injects half of its recycled water into wells underground.

The pressure is enough to stop seawater from contaminating its current supply of groundwater.

The other water sources include water from the Santa Ana River.

It takes at least six months until the stored groundwater can be extracted again.

Michael Markus, general manager of Orange County Water District, said: "We're ground water managers. Our problem is -- this area is dependent on two outside sources of water.

"So over the years, it's become evident that we need to build local water supply reliability and that's why we built the Groundwater Replenishment System... so that we could have that reliable source of water that we can depend on, that we could replenish our aquifers which become part of our potable drinking water supply.

"It helps us become somewhat independent from those outside sources of water."

Harry Seah, chief technology officer of PUB, said: "In a way, the driver here is that instead of incurring so much energy to pump water across the Rocky (Mountains), Colorado, and then taking water from the north of California, where it's long distance, looking at this project helps us to understand that we also need to utilise our own resources efficiently and in a sustainable way of managing the system -- so that in the end, you can have good, affordable water."

While it is still at an early stage, PUB said it is also looking at the California agency's water management system as it embarks on its own groundwater journey.

PUB forms team to study groundwater use
It plans to install 20 to 30 wells in western S'pore, monitor water flow
By Feng Zengkun, Environment Correspondent, In Orange County, The Straits Times, 25 Mar 2014

SINGAPORE has ramped up efforts to study whether and how the country's underground water can be extracted for use.

National water agency PUB has formed a team of international experts to advise it, and will dig its first exploratory monitoring wells in the next few months.

It is interested in the subterranean Jurong rock formation in western Singapore, which could hold water-bearing layers of rock called aquifers.

Even if Singapore is unable to extract substantial water from them regularly, such aquifers could act as "water banks" for drought periods, said PUB chief technology officer Harry Seah.

While there is no timeline for when this water could contribute to Singapore's supply, the exploratory efforts will help to prepare the country, he said.

"We are building up our expertise in the field... and if groundwater does become feasible, we will have a ready team to manage the groundwater resource."

The PUB plans to install 20 to 30 monitoring wells in western Singapore and monitor the flow of water through them for six to 12 months. These wells will be about 5cm wide and 10m to 20m deep. Their locations are being worked out, but likely options include green verges alongside roads and other public areas.

Among other things, they will help find out where rainwater goes after it seeps into the ground.

"For example, we want to know how much of it goes vertically down into aquifers, and how much horizontal movement there is instead," said Mr Seah.

This information will be useful when Singapore looks into how much water is available, how much of it can be safely extracted, and how fast it can be extracted such that rainfall can naturally replace the removed water.

To speed up the learning process, PUB has asked six experts around the world for help. They include: Lord Ronald Oxburgh, a noted geologist and geophysicist; Professor Ken Howard, president of the International Association of Hydrogeologists and an expert in urban groundwater management; and Mr Roy Herndon, chief hydrogeologist at the Orange County Water District in California, which has been extracting groundwater for decades.

Although he played down suggestions by reporters that underground water could be Singapore's fifth tap - after imports from Malaysia, recycled used water and treated seawater and rainwater - Mr Seah added that there is always urgency for the PUB to explore new ideas.

The PUB studied underground water in eastern Singapore in the 1990s, but the data from the technology used then did not give the agency "adequate confidence" that extracting the water would be sustainable or safe.

"As Singapore progresses, the water demand will keep growing. If we continue with business as usual, the energy needed will grow much faster as we ramp up desalination and NEWater to meet demand. It's not sustainable," said Mr Seah.

While the PUB has embarked on research to reduce the energy needed for water treatment, "groundwater is freshwater", he added. "If we have abundant rainwater, we can inject some into the ground, increase our storage... extract the water to meet our demand and give us more buffer for drought."


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