Audrey Tan and Jacklin Kwan Straits Times 29 Aug 19;
SINGAPORE - One of Singapore's oldest water treatment plants has been upgraded with state-of-the-art technology, in a move that will boost the Republic's water resilience in the face of climate change.
The upgraded Choa Chu Kang Waterworks, which is also more energy- and cost- efficient now, was officially opened by Minister for the Environment and Water Resources Masagos Zulkifli on Thursday morning (Aug 29).
The Choa Chu Kang plant treats water from Kranji, Pandan and Tengeh reservoirs before it is delivered to taps in homes, businesses and industry.
Climate change may cause the quality of water in Singapore's reservoirs to deteriorate, said Mr Masagos during the event.
He pointed to how rising temperatures could result in warmer waters, while intense rainfall could lead to an excessive amount of nutrient runoff being washed into waterways and reservoirs.
"These conditions are likely to fuel algae growth in the reservoirs, which will need to be removed as part of the water treatment process," said Mr Masagos.
In anticipation of such challenges, national water agency PUB has to continuously invest in new water treatment technologies and upgrade our water treatment plants, as was done in Choa Chu Kang, he added.
Professor Shane Snyder, executive director for the Nanyang Environment and Water Research Institute at the Nanyang Technological University (NTU) said the new ceramic membranes at the Choa Chu Kang plant could tackle a wide range of water quality.
"This will allow Singapore to be more secure in providing safe and reliable water to its citizens," he added.
THE UPGRADE
In the $162 million project spanning three years, the old sand filtration system at the plant in the west has been replaced with ceramic filtration membranes, which are more efficient at removing suspended particles from raw water.
As part of the upgrade, ozone-biological activated carbon filters were also added to the water treatment process.
This additional step in the water treatment process further helps to destroy microbes and remove organic matter from the water, said PUB.
Similar ceramic membrane systems are also used at water treatment facilities in the Netherlands and Britain, although it is the first for Singapore.
The Choa Chu Kang plant is now also the world's largest ceramic membrane water treatment plant.
PUB chief executive Ng Joo Hee said the upgraded plant allowed the water agency to carry out advanced treatment of the tap water that is supplied to homes, commerce and industry.
He added: "That we are able to deploy this new technology on such a large scale is the result of years of research, experimentation and rigorous testing."
UPGRADING MILESTONES
Choa Chu Kang Waterworks was built in two phases in 1975 and 1981 respectively, with two facilities to treat 40 million gallons per day (mgd) (181 million litres per day) of water each.
In total, the 80 mgd (362 million litres per day) of water that the plant can process is equivalent to about 145 Olympic-sized swimming pools.
In 2008, the first 40 mgd per day facility was upgraded, with polymeric membranes replacing sand filters.
In 2016, work to replace the sand filtration system with ceramic membranes started on the second facility. This was completed in June 2019.
NTU's Prof Snyder said ceramic membranes have numerous advantages over sand filtration systems, in terms of strength and larger filtration capacity, among others.
But most importantly, it was also safer, he said.
Ceramic membranes have uniform pore size that sand filtration systems do not, he said. This, coupled with high material stability, make them an ideal technology for pathogen removal, the most paramount aspect of water safety, said Prof Snyder, who conducts research into ceramic membrane technology.
"Ceramic membranes can be combined with oxidation technologies, such as ozonation, whereby the membrane and ozone together create a barrier that can eliminate most water contaminants, both biological and chemical," he added. "Ceramic membranes will produce a safer and higher quality water than traditional sand filtration systems."
In comparison to polymer membranes, ceramic membranes last longer, said PUB.
Ceramic membranes can last about 20 years, four times longer than the five-year lifespan of polymeric membranes.
Water loss is also reduced significantly from 5 per cent to 1 per cent with the use of ceramic membranes, the agency added.
WATER RESILIENCE
Water is an existential issue for Singapore, Mr Masagos said on Thursday.
He said: "Climate change has made water an issue every country will have to grapple with in the near future.
"I am glad that Singapore has been on a quest to address our water issues for the longest time, and am confident that we will continue to address our water supply needs."
To further boost Singapore's water resilience even as climate change is causing rainfall patterns to change, PUB is also looking to weather-proof Singapore's water supply by treating used water and by desalination.
Choa Chu Kang Waterworks' S$162m upgrade to help Singapore tackle climate change challenge
Ang Hwee Min Channel NewsAsia 29 Aug 19;
SINGAPORE: Choa Chu Kang Waterworks (CCKWW) has completed a S$162 million upgrade that will help it tackle challenges in processing raw water as a result of “the negative impacts of climate change”.
The upgrades, which include a ceramic membrane filtration system, were unveiled by Minister for Environment and Water Resources Masagos Zulkifli on Thursday (Aug 29).
Mr Masagos said the quality of Singapore’s catchment water may deteriorate with climate change.
“For instance, rising temperatures could result in warmer waters while intense rainfall may lead to an excessive amount of nutrient runoff being washed into our waterways and reservoirs,” the minister stated.
“These conditions are likely to fuel algae growth in the reservoirs, which will need to be removed as part of the water treatment process.
“In anticipation of such challenges, (national water agency) PUB has to continuously invest in new water treatment technologies and upgrade our water treatment plants, as we have done in Choa Chu Kang.”
One of Singapore’s oldest water treatment plants, CCKWW was built in two phases in 1975 and 1981. The three-year upgrade from June 2016 to June 2019 saw the construction of a new facility, installation of ceramic membranes and the inclusion of ozone-biological activated carbon (BAC) treatment for the plant.
The ceramic membrane system, the world’s largest in a single plant, will treat up to 40 million gallons of water per day. Filtering out particles as minute as 0.1 micrometres in size, there will be 12 vessels with 90 ceramic membrane elements in each vessel.
It is more energy and cost efficient than polymeric membranes, said Mr Masagos, adding that the ceramic membrane system only sees 1 per cent of water loss, compared to 5 per cent for a polymeric membrane system. The new membranes are expected to last for 20 years, compared to polymeric membranes that have to be replaced every five years.
Besides the ceramic membranes, the upgrade will also see the implementation of ozone-BAC treatment at the plant.
Ozone, one of the strongest disinfectants in drinking water treatment, kills germs in the water, while activated carbon removes other natural organic impurities, said the minister.
“The installation of the ceramic membranes together with the ozone-BAC system means that Choa Chu Kang Waterworks possesses one of the most advanced water treatment processes in the world,” Mr Masagos added.
NEGATIVE EFFECTS OF CLIMATE CHANGE
“That we are able to deploy this new technology on such a large scale is the result of years of research, experimentation and rigorous testing,” said Mr Ng Joo Hee, chief executive of PUB.
“Advanced treatment technologies will allow us to cope with the impact of an increasingly urbanised catchment and the negative effects of climate change on Singapore’s raw water quality.”
CCKWW is Singapore’s second-largest waterworks, and treats 80 million gallons of water from Kranji, Pandan and Tengeh reservoirs, equivalent to 145 Olympic-sized swimming pools.
PUB said it has plans to progressively incorporate advanced water treatment processes in the other five water treatment plants in Singapore - Bedok Avenue, Bukit Timah, Chestnut Avenue, Lower Seletar, and Woodleigh Waterworks - when they are “due for upgrade”.
Chestnut Avenue Waterworks and Woodleigh Waterworks are currently being upgraded to include ozone-BAC steps in the water treatment process, PUB said. This is expected to be completed by the end of this year.
PUB also signed a memorandum of understanding (MoU) with PWN from the Netherlands and South West Water from the United Kingdom to share knowledge of the latest innovations, as well as operational data and best practices on ceramic membrane systems for the next five years.
All three utilities are currently deploying ceramic membrane systems in their water treatment plants.
“Our rigorous water treatment processes and quality monitoring programme from source to tap allow all Singaporeans to drink tap water safely without the need for boiling or extra filtration – a privilege not enjoyed by the vast majority of the world’s population,” said Mr Masagos.
“Climate change has made water an issue every country will have to grapple with in the near future. I am glad that Singapore has been on a quest to address our water issues for the longest time, and am confident that we will continue to address our water supply needs.”
Source: CNA/mn
