PUB aims to double water supply by 2060 without using more energy or producing more waste

LOUISA TANG Today Online 4 Jul 18;

SINGAPORE — National water agency PUB has set a target to meet future demand by doubling the amount of clean water it produces today by 2060 without using more energy.

That is one of several long-term goals that the PUB committed to on Wednesday (July 4), as it soldiers on with research and development (R&D) efforts to increase water resources for the future and improve water treatment efficiency.

Through new technologies, it aims to reduce the energy used in desalination by more than two-thirds, increase the amount of NEWater recovered from used water to 90 per cent at low energy levels, and produce as much energy as it uses in treating used water.

Since 2002 till last year, the agency, its research partners and the National Research Foundation have pumped in S$453 million in 613 water R&D projects, more than three-quarters of which have moved towards full-scale deployment.

The agency is also looking into reducing the amount of waste — produced in the form of sludge — that it has to dispose of. Sludge, a mixture of organic materials, minerals and other waste materials filtered out during water treatment, is costly to incinerate and dispose of in the landfill.

Of Singapore's four national taps, desalinated water and NEWater meet up to 70 per cent of today's water demand. That is projected to go up to 80 per cent in 2030 and 85 per cent in 2060.

Desalinated water, which currently meets up to 30 per cent of water demand and will meet 30 per cent of future demand in 2060, is the most energy-intensive water source. NEWater, on the other hand, currently makes up 40 per cent of water demand, and meet up to 55 per cent of future demand in 2060.

However, both desalinating seawater and getting NEWater from used water require between five and 17 times more energy than the conventional method of treating rainwater.

Mr Harry Seah, PUB's assistant head of future systems and technology, said that if PUB sticks to current technologies, it will have to use four times more energy and produce twice as much sludge as today to meet Singapore's water demand in 2060. This is unsustainable and can only be overcome using innovative technologies.

"The question is affordability. We are expecting the cost of energy to go up," he added. "If we don't do anything today, the cost of producing water is going to go up too."

While Mr Seah stopped short of saying this would lead to higher water prices for consumers, he noted that being efficient with energy usage is key to maintaining water prices.

"There are a lot of other factors besides energy — there's manpower, for example. We do our part through efficiency to drag (having to increase prices) as long as possible," he said.


Over the next five to 10 years, the agency plans to reduce its energy consumption for desalination by more than half. In the long term, it plans to whittle this down to more than two-thirds.

One method PUB is testing out at its R&D facility in Tuas is the electro-deionisation technology. This technology uses an electric field to pull dissolved salts from seawater, which requires less energy than the current method of reverse osmosis — pushing seawater through membranes that filter out salts and impurities.

The PUB plans to implement the technology, alongside reverse osmosis, next year at the newly opened Tuas Desalination Plant. It also plans for Singapore's sixth desalination plant, which has not been identified yet, to process seawater using purely electro-deionisation.

Another method being studied at the Tuas R&D facility is the biomimetic membrane. These membranes use natural proteins found in cell membranes that can desalinate seawater more efficiently.

As for NEWater, where the current amount of energy used turns only 75 per cent of the treated used water into NEWater through reverse osmosis, PUB's goal is to up the production to 90 per cent using less than half of the energy used.

Lastly, in the short term, the agency wants to be able to produce as much energy as it uses in water reclamation plants. To do so, it is tapping on sludge, which is usually seen as a waste product.

However, when sludge breaks down, it produces biogas, which can be used as a source of energy. Since at least the 1990s, PUB has been using sludge to produce biogas, which it then uses to power the water reclamation plants.

Currently, this method of using sludge to produce biogas allows PUB's water reclamation plants to produce 25 per cent of the energy it requires. The plan is to move the energy self-sufficiency level to 75 per cent, with the ultimate goal set at 100 per cent.

Through this, PUB can also reduce the amount of sludge it has to dispose of by more than 50 per cent in the long term. The process will double the amount of used water that can be treated at today's sludge footprint too.

The various technologies being tested will be showcased at Singapore International Water Week 2018, to be held from Sunday (July 8) to July 12.

Need more water? PUB aims to produce more with same amount of resources
Aqil Haziq Mahmud Channel NewsAsia 4 Jul 18;

SINGAPORE: Every time you go to the toilet, your waste enters the sewers as used water, gets treated at a water reclamation plant, then processed into NEWater or released into the sea.

The treatment process also produces sludge, a mud-like mixture of solid and liquid bits that goes into the incinerator and then dumped in the landfill.

Sounds simple enough, but there's a problem: It's not just a bit of mud.

Singapore consumes 430 million gallons of water a day (mgd), enough to fill 782 Olympic-sized swimming pools, and generates 300,000 tonnes of sludge a year, equivalent to the weight of 3,000 buses.

These figures are not about to go down. By 2060, when Singapore is set to use twice the amount of water it does now, it will generate 600,000 tonnes of sludge annually.

This presents a challenge, as Semakau Landfill is projected to run out of space by 2035 at the current rate waste is being generated and burnt.

Enter national water agency PUB, which is trying to recycle more of the sludge into biogas, an important source of energy.

PUB is already turning some of the sludge into biogas, which means its four water reclamation plants are 25 per cent energy self-sufficient.

This is because its plants have digestors that convert the organic matter in sludge into biogas, which can in turn power generators.

But within the next decade, PUB wants its plants to be fully energy self-sufficient. This means turning even more sludge into biogas through technological innovations.

One way is through a thermal hydrolysis process (THP), which pre-treats sludge using high temperature and pressure to improve its breakdown rate in digestors. This allows more organic content to be converted to biogas.

PUB is testing this technology at a demonstration plant at the Jurong Water Reclamation Plant. The demonstration plant can treat up to 70 tonnes of sludge a day.

The agency is also testing a "novel combination" of processes, including a biologically enhanced treatment facility and energy-efficient membrane bioreactor (MBR) that helps shorten the treatment process, reduce energy use and maximise biogas production.

This combination is being validated at the Ulu Pandan wastewater treatment demonstration plant, which uses 40 per cent less energy than a typical plant.


Besides extending landfill lifespans, how will reducing the energy and waste footprint of treating used water benefit people?

As PUB explains, used water treatment is the "backbone" of NEWater production, which currently supplies up to 40 per cent of Singapore's water demand. By 2060, NEWater will supply up to 55 per cent.

The same goes for desalinated water, another national tap that will be stretched by rising demand.

“Meeting future water demand with today’s technologies will see PUB’s energy footprint quadruple to 4,000GWh/year and the amount of sludge generated double to over 600,000 tonnes a year by 2060,” PUB said on Tuesday (Jul 3). “This is unsustainable and can only be overcome by leveraging technological innovations.”

That energy footprint would have been enough to power 686,000 5-room Housing and Development Board flats for a month.

“The price of energy is going to go up,” PUB's assistant chief executive (future systems and technology) Harry Seah said. “If you don’t do anything today, the cost of producing water is going to go up.”


When asked if the technological innovations would help keep water prices stable, Mr Seah said “we do our part through efficiency to drag it (out) as long as possible, that’s the best I can do”.

Since July, the price of water has gone up 30 per cent following a two-step increase. The hike was in line with the rising costs of producing water.

“Whether the price will go up, I don’t know, but we can try our best to make our water affordable to the public,” he added, highlighting that it would also depend on other factors like manpower.

“Basically, we have to look at it from the point of view of sustainability, besides dollar and cents.”


And so PUB's target is clear: Produce double the amount of water to meet 2060 demand, but with the same energy and waste footprint.

To do this, it has - together with partners - invested an average of S$30 million a year in water technology research and development (R&D), enabling technologies like THP and MBR to progress beyond proof-of-concept.

For instance in desalination, PUB has invested in electro-deionisation (EDI) technology, which uses an electric field to extract dissolved salts from seawater.

In contrast, desalination is currently done by reverse osmosis (RO), which involves pushing seawater through membranes that filter out salts and impurities.

The fact that EDI revolves around extracting a small component out of a larger base, as opposed to other way round in RO, means it consumes less energy.

While current desalination technology uses 3.5kWh/m3, an EDI demonstration plant in Tuas is consuming 2.4kWh/m3 to process 3,800m3 of water a day.

The target is to bring this down to 1.8kWh/m3 by the end of the year, while there are also plans to further validate the technology at 10,000m3 of water a day at the new Tuas Desalination Plant.

Beyond EDI, PUB is pouring resources into other water technologies ranging from electrical fields to cell membranes, all in the name of reducing energy consumption.


While these bode well for boosting the efficiency of water supply, Mr Seah insisted that managing water demand is equally important.

“Even when I say water demand is doubled, I’m going to try ways and means to impede the rate of increase of the demand,” he said.

Mr Seah said the PUB has been “quite aggressive” in encouraging industries to recycle their processed water, in a bid to reduce demand by 3mgd every year.

As for consumers, Mr Seah said the automated meter reading (AMR) project will help PUB monitor efficiency and energy savings, as well as calibrate demand and supply.

In 2016, PUB piloted the project to provide some 500 households in Punggol with “timely” information on water consumption.

“Most important, it is to change the behaviour of consumption,” Mr Seah added. “If you turn it into a behavioural change, if a member of the public thinks it’s the last drop, then you will be very careful using water.”

Source: CNA/hz

PUB focuses on squeezing more value out of each drop of clean water produced
Audrey Tan Straits Times 4 Jul 18;

SINGAPORE - With the search for new water sources reaching its limits, Singapore is setting its sights on another key area of research, to make sure it squeezes more value from each drop of clean water it produces.

A significant chunk of the $435 million that has gone into water research and development (R&D) here has gone into making water treatment processes less of a drain on electricity.

"We are pushing the frontier of water technology to tackle the pressing challenges in energy and sludge management efficiency," said Mr Harry Seah, national water agency PUB's assistant chief executive for future systems and technology, on Wednesday (July 4).

This comes as Singapore becomes increasingly reliant on its two weather-proof sources of water - desalination and water reuse - against a backdrop of erratic weather, he said.

"The challenge is to ensure that technological advancements continue to keep up with increasing water demand so these sources remain sustainable," Mr Seah added.

He was giving the media an update on Singapore's research into water ahead of a global water conference, the Singapore International Water Week, in Marina Bay Sands next week.

Up until the early 2000s, Singapore has been reliant on rain falling in its reservoirs or Malaysia's Johor River to meet its water needs.

PUB and research partner to reduce energy consumption of seawater desalination
A new "tap" came online in 2002 with Singapore's launch of Newater (recycled used water), and again in 2005, when the Republic's first desalination plant in Tuas was opened.

Today, both these taps can meet up to 70 per cent of Singapore's water demand of 430 million gallons a day, and are projected to help meet up to 85 per cent of future water demand in 2060. Demand for water is expected to double by then.

But both these water treatment methods require plenty of energy. Between five and 17 times more electricity than that used to treat rainwater is needed to produce water through desalination or treatment of used water. The latter also produces sludge, which is ultimately landfilled.

PUB said that meeting future water demand with today's technology will see PUB's electricity requirement go up four times to 4,000 GWh a year, with the amount of sludge generated doubling to 600,000 tonnes a year by 2060.

"This is unsustainable and can only be overcome by leveraging technology," said Mr Seah, adding that Singapore's long-term goal is to meet water demand with the current amount of energy and sludge produce.

While Singapore is not constrained by energy as it is by water and land, it is still in Singapore's interests to keep this requirement low to save on costs, and to fulfil its international climate pledge to reduce its carbon footprint, Mr Seah said.

To this end, PUB collaborates with research institutes and the private sector on research projects, including how to cut energy requirements of desalination.

One example is a collaboration on desalination technology that PUB has with American company Evoqua, that can halve energy requirements for desalination.

Assistant Professor Winston Chow from National University of Singapore's geography department said that while new water "taps", such as groundwater extraction, can be explored further, Singapore has succeeded in enhancing its water supply through desalination and Newater.

"It's thus more sensible to invest in making these taps more efficient and cheaper for both domestic and commercial water users here."

He added that there are direct and indirect environmental benefits to increasing the efficiency of the existing water treatment methods.

"The local environment directly benefits if there is reduction in brine (salty discharge from desalination) and sludge, and less energy use contributes to lowering Singapore's long-term energy intensity commitments, as set out in its pledge in the Paris Agreement," said Prof Chow.

Water expert Asit Biswas, distinguished visiting professor at the Lee Kuan Yew School of Public Policy and Stockholm Water Prize winner, cautioned that managing demand has to be an essential component of ensuring Singapore's future water security.

"We have reached a plateau in what technology can do for us in increasing water supply. Further advances are likely to be incremental rather than transformational," said Prof Biswas.

He added: "What could be transformational is significant emphasis on domestic and industrial demand management by all means available. All should realise that water is a limited and precious resource, and must be used prudently."

PUB and research partner to reduce energy consumption of seawater desalination
Luke Anthony Tan Straits Times 4 Jul 18;

SINGAPORE - To meet Singapore’s water needs and reduce the energy costs of treating seawater, national water agency PUB and its research partner Evoqua Water have announced a new process that can potentially reduce the energy consumption of seawater desalination by half.

Currently, up to 30 per cent of Singapore’s water needs is desalinated by reverse osmosis, a process which pushes seawater through membranes that filter out dissolved salts and minerals.

This form of water treatment, according to PUB, uses about 3.5kwh to produce one cubic m of desalinated water. However, Evoqua Water has developed new desalination modules which use electro-deionisation (EDI) technology. This uses electric currents to remove dissolved salts and minerals from seawater.

These EDI models have been used at a demonstration plant at Tuas since March and are able to treat 3,800 cubic m of seawater per day.

The rate of energy consumption of this plant is at 2.4kwh per cubic m of water treated, according to Mr Harry Seah, assistant chief executive at PUB.

In 2009, PUB and Evoqua Water had shown - using proof-of-concept EDI models - that they could achieve an energy consumption rate of 1.65kwh per cubic m of seawater.

Hence, Mr Seah added that any new desalination plant would also use EDI technology and hopes to bring down the rate of energy consumption to 1.8 kwh per cubic m of seawater by next year as desalination operations are being scaled up at the Tuas demonstration plant.

The new Tuas Desalination Plant. Up until the early 2000s, Singapore has been reliant on rain falling in its reservoirs or Malaysia's Johor River to meet its water needs.

Energy consumption rates aside, Dr Qiao Xiangyi, Evoqua’s research and development manager, said the production costs of the EDI technology have been reduced to a fraction of its original cost - from half a million dollars to about $40,000.