NUS team fits plastic decoy with robotics equipment to perform tests in water bodies

This 'swan' is no bird brain
Grace Chua Straits Times 27 Oct 13;

If you spot a swan bobbing gently in a reservoir or canal, take a closer look. There could be a lot more going on beneath the surface than paddling feet.

National University of Singapore (NUS) researchers have kitted out a plastic decoy swan with equipment and robotics so it can float around testing water quality, transmit findings wirelessly, return on its own to a charging dock and even call for help if it is nicked.

Such decoys are used in Canada to stop noisy, messy geese from landing on ponds, but NUS researchers performed a little surgery on one to add electronics to its innards, and Global Positioning System and wireless sensors to its head.

Its undercarriage bears a cylinder that can be fitted with sensors for chlorophyll, pH, dissolved oxygen and any other water-quality measure desired.

Lead researcher Mandar Chitre, head of the Acoustic Research Laboratory at the university's Tropical Marine Science Institute (TMSI) and an electrical and computer engineering assistant professor, said the project stemmed from a need to monitor the quality of freshwater bodies.

The swan saves manpower, he said. It can also provide measurements over time and over a large area, compared with, say, having fixed sensors or sending out people to test water from a boat.

The swan is also easier to maintain and cheaper than submerged robots, added research associate Koay Teong Beng.

The project is among dozens of efforts that have propelled Singapore into the top ranks of the global water research community.

In a survey by consultancy Lux Research earlier this year, NUS came in No. 1 in water research and Nanyang Technological University (NTU) second, among about 400 universities and institutes worldwide.

Since 2006, Singapore has committed $470 million to grow the water sector. NTU's Nanyang Environment and Water Research Institute this year received an extra $132 million until 2016 from the industry, public agencies and grants from funding bodies.

The NUSwan (New Smart Water Assessment Network) project by the NUS Environmental Research Institute and the TMSI evolved from existing work on underwater autonomous robots.

The swans can paddle about at a top speed of two knots, or a little over 3.5kmh, and currently cost some $20,000 to $30,000 to develop. But the cost could drop when they are produced commercially.

The long-term vision is to have a flock of such robots that can also be used to map out coral reefs and monitor their health, said Dr Chitre.

But what about the fact that swans are not native to Singapore? "If you want to increase the biodiversity, you can use a different species," he quipped.

Big task to remove tiny particles in water
Singapore is seen as a world leader in water research, and has committed substantial amounts of public funding to grow its water sector. The Sunday Times looks at some of the work done to safeguard Singapore’s water quality
Grace Chua Straits Times 27 Oct 13;

Nanoparticles - tiny particles of materials like silver and gold, a fraction of the size of a virus - have special properties. They can be used in antibacterial coatings, to kill tumours, or to deliver drugs.

But they can be a double-edged sword.

The same properties that enable them to enter and kill cancer cells or bacteria also mean they can be toxic to healthy cells in the wrong context.

The use of nanoparticles has become more widespread in recent years, and they can be found in thousands of consumer products ranging from sunscreen to food packaging.

Scientists have yet to fully understand where these particles end up, and their effect on human and environmental health.

That's why researchers at the National University of Singapore (NUS) and Hebrew University of Jerusalem are working together on how best to detect and remove such nanoparticles from water, especially using low-cost, readily available materials.

Professor Suresh Valiyaveettil of the NUS chemistry department said silver nanoparticles have been shown to kill cells and cause abnormalities in zebrafish, the guppy- size fish popular in toxicity testing because their reactions are similar to humans'.

Increased use of nanoparticle products will increase the concentration of nanomaterials in the environment, particularly water, if their manufacturers do not deal properly with waste, he added.

Prof Suresh said: "The next question that came up in our mind was, 'How do we remove such contaminants from the water supply?' How do we detect these tiny particles in contaminated water? Do the existing methodologies of water purification remove these emerging contaminants?"

So he and his colleagues worked with a water treatment expert, Professor Avner Adin, of the Hebrew University of Jerusalem.

Earlier this year, they found that apple and tomato peel and other food wastes like sugar cane residue and soybean hulls could be used to remove nanoparticles and other contaminants from water.

They also found that nanoparticles clung to the surface of metal oxides like zinc oxide (the white powder commonly used in zinc sunscreens), and suggested that the nanoparticles could be clinging to charged areas on the surface of the oxide particle.

"All materials used in our lab are relatively easy to get in large amounts and can be modified to fit the need of certain communities," he said.

Now the researchers are looking for collaborators for field trials of these materials, Prof Suresh said.

Finding the right mix of minerals for purified water
Straits Times 27 Oct 13;

Singapore is ramping up its desalination programme so that it can get even more fresh water from the sea.

This year, it opened its second desalination plant at Tuas, and desalinated sea water can now meet up to a quarter of the nation's water needs.

After the salt and minerals are taken out of the sea water, however, it becomes very pure.

This super-pure water can leach minerals from metal water pipes, so minerals must be added before the water goes into the distribution networks - just enough to prevent damage to the pipes, but not so much that mineral deposits form in them.

Researchers are figuring out what minerals to add, how much and at what concentrations would be best for the pipes.

Currently, Singapore adds some calcium to its desalinated water and Newater to prevent pipe damage. In some countries, minerals such as calcium and magnesium are also added to drinking water for health reasons such as to keep bones strong.

Associate Professor Hu Jiangyong, deputy head of research at the National University of Singapore's civil and environmental engineering department, together with colleagues and collaborators from national water agency PUB, compared various concentrations of calcium and magnesium in the water, based on what is added to desalinated water around the world.

They found that using calcium and magnesium together was better at preventing corrosion than calcium alone. But the exact ratio and amount need to be studied further, Prof Hu said.

The team also looked at three types of pipes - ductile iron and cast iron, which older distribution pipes are made of - and newer cement-lined ductile iron pipes.

They found cement-lined pipes were better at staving off corrosion than the older metal pipes.

Now they want to more closely simulate real-life conditions in tests, using segments of pipeline rather than just pieces of pipe wall, said Prof Hu.

"We hope to better understand the technical details and provide more technical information to the authorities," she said.

Grace Chua