Posted in | Nanotechnology | Water

NTU Researchers Invent New Nanofilter for Efficient Wastewater Treatment

A team of researchers from at Nanyang Technological University (NTU) Singapore have developed a new nanofilter capable of reducing the energy required to treat wastewater. The amount of energy is reduced up to five times the normal quantity required for the treatment.

(left to right) NTU Senior Research Fellow Dr Shi Lei, NTU’s Singapore Membrane Technology Centre Director Prof Wang Rong, De.Mem’s CTO Dr Adrian Yeo and NTU Research Fellow Dr Zhao Shan Shan. (Credit: Nanyang Technological University)

An ultrafiltration (UF) membrane, which filters out the small particles, is used prior to the use of a reverse osmosis (RO) membrane in the final steps of water purification in a wastewater treatment method. The water is made to pass through a very thin membrane at high pressure in the reverse osmosis process. This process helps to separate water molecules from any kind of residual contaminants, which are a thousand times smaller in size than the width of a human hair. Contaminants that are trapped include heavy metals, salt, and harmful chemicals such as benzene.

The water pressure has to be high, about 10 bars or more, which means that a large amount of energy is required for the water pumps.

Reverse osmosis and ultrafiltration are eliminated by NTU’s proprietary nanofiltration (NF) hollow fiber membrane by combining the two processes.

This method needs only 2 bars of water pressure to generate water that is almost as pure as water yielded through reverse osmosis. The pressure used to filter out the same type of contaminants is comparable to the pressure created in a regular home pressure cooker.

It took roughly two years for NTU’s Nanyang Environment and Water Research Institute (NEWRI) to create this advanced technology. At present, this technology is commercialized through De.Mem, an NTU spin-off company.

A pilot production plant will be built by De.Mem in Singapore for production of new membranes. This company also owns several water treatment plants in Singapore and Vietnam.

NTU Professor Ng Wun Jern, the executive director of NEWRI, stated that the recent technology is the first of its kind to reach the market, and therefore is a huge step forward for Singapore.

With the increasing urbanization of cities and fast growing global population, more cities and communities will face an unprecedented challenge to meet its growing demand for clean water and wastewater treatment. If we are to address the ever increasing demand for clean water, what the world needs are innovative technologies like NTU’s new nanofiltration hollow fiber membrane that allow us to treat and produce extremely clean water at a low cost, yet have high reliability and are easy to maintain.

Professor Ng Wun Jern, NTU

The team involved in designing the new NF membrane was led by NTU Professor Wang Rong, the director of NEWRI’s Singapore Membrane Technology Centre. He says that the team had designed the NF membrane for commercial scale-up and production.

“One of the main challenges faced by the industry is that current reverse osmosis processes are energy intensive, with down time needed for maintenance,” explained Prof Wang, who is also the Chair of NTU’s School of Civil and Environmental Engineering. “Our new membrane is also easy to manufacture using low-cost chemicals that are 30 times cheaper than conventional chemicals, making it suitable for mass production.”

The gap in the current market for water treatment solutions is filled by the new membrane, said Mr Andreas Kroell, Chief Executive Officer of De.Mem.

We have seen in the labs that when we treat industrial wastewater with the new nanofiltration membranes, the quality of clean water produced is comparable to reverse osmosis but requires much lower pressure, hence lowering costs. Such an effective and efficient technology has significant market potential and can be used in many of De.Mem’s projects that involve the treatment of industrial wastewater.

Andreas Kroell, Chief Executive Officer, De.Mem

Prior to scaling up to a full industrial production line, De.Mem will be testing the efficiency and effectiveness of the new membrane modules in real world scenarios in its plants.

The new membrane technology by NTU will also be exhibited during Singapore International Water Week happening from 10 to 14 July.

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