Singapore University leads the way in industrial wastewater purification

Posted 24 January 2018

National University of Singapore
Removing hard-to-treat organic compounds from industrial wastewater may soon be a lot easier thanks to a new approach developed by National University of Singapore (NUS) scientists that utilises electricity to purify water. 

Using electricity as a reagent for purification, the method can remove up to 99% of organic compounds found in various types of industrial wastewater.

NUS Faculty of Engineering Assistant Professor and Lead Researcher Olivier Lefebvre told PhysOrg the new approach is not only effective, but also great for the environment, too.  

"Despite the great advances in wastewater treatment technologies, the removal of refractory organic compounds remains a costly and challenging process,” he said. 

“Our invention provides an environmentally-friendly solution and helps to raise the overall standard of industrial wastewater treatment.”

The system operates on small amounts of electrical currents and does not generate secondary waste, such as sludge, which cuts costs on residual waste processing.

The system can be used for a range of different industries, including the electronics and pharmaceutical industries with wastewater containing mixtures of complex organic substances, and also agriculture, with wastewater containing high concentration of pesticides or herbicides.

Because the system utilises electrochemistry, it removes the need for chemicals to be added. Wastewater is pumped into the system’s chamber and, as electric currents are passed, electrodes generate hydrogen peroxide and hydroxyl radicals. 

These components react with the complex organic compounds in the water and work to continuously break down them into simpler molecules, until all organic contaminants have been degraded into water and carbon dioxide.

"Our electrochemical system has shown that it can achieve complete mineralisation of any organic pollutant. This means the system can completely remove organic compounds in the wastewater by degrading them into water and carbon dioxide,” Lefebvre said. 

“This novel system can also be incorporated as a pre-treatment to an existing wastewater treatment scheme. 

“It operates on low electrical power and the system could easily be combined with solar power and other purification methods such as using membranes and biological treatments.”

Lefebvre said the new system could potentially also be utilised by heavy manufacturing industries that require ultrapure water for their processes such as mining, oil and gas. 
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