New Insights on Membrane Technology from Singapore International Water Week 2024

It was great to be back in Singapore for the first time since the pandemic. On the first day (Tuesday, 18 June), I visited the NEWRI center, where I have spent a lot of time collaborating at the Singapore Membrane Technology Center (SMTC), part of the Nanyang Technological University (NTU). There have been some management changes, and Professor Rong Wang took over from Professor Shane Snyder earlier this year. Nevertheless, I was able to catch up with some longtime friends. The research focuses on membrane fouling indicators and electrodialysis, which closely aligns with our interests at KWR.

The NEWRI/SMTC center at the NTU campus

Dr Babu Narayanswamy (SMTC/NEWRI)

Prof. Chong Tzyy Haur and Prof. She Qianhong (SMTC/NEWRI)

Dr LeeNuang Sim (SMTC/NEWRI) at the NTU booth at the SIWW

In the evening, it was a pleasure and honour to attend the Lee Kuan Yew Prize Ceremony. Our colleague Professor Gertjan Medema was awarded the prestigious Lee Kuan Yew Prize 2024. It is often considered the Nobel Prize on Water Research, and LKY couldn’t have gone to a more deserving recipient than Gertjan, who became a minor celebrity for the rest of the week. 

The SIWW – Water Convention

Over the next few days (Wednesday, 19 June – Friday, 21 June), the Water Convention, part of the Singapore International Water Week (SIWW), was in full swing. The opening lectures emphasised the urgent need for transformative adaptation in the water sector in response to severe climate change. Speakers strongly called for equity and a shift toward being more nature—and people-positive. They advocated for breaking down silo-thinking and addressing the climate and nature crisis through conventional and unconventional partnerships.

The entrance of the SIWW 2024 convention halls

Opening speeches at the Water Convention

Brine mining or brine treatment was a prominent topic in multiple parallel and poster sessions at the Water Convention. As the use of reverse osmosis continues to rise globally, managing resulting brine (concentrate) streams is increasingly seen as both a challenge and an opportunity for resource recovery. Various technological solutions were showcased at the convention on lab and pilot scales. These included novel ion-selective membranes, solvent-driven crystallization, assisted osmotic reverse osmosis and selective electrodialysis. A critical aspect of these solutions is the fractionation of brine streams in monovalent, multivalent, and organic-enriched solutions, an important research focus at KWR. 

The fate of PFAS in treatment processes was another hot topic at the convention, indicating a global concern. Several studies confirmed that reverse osmosis effectively acts as a barrier against these undesired compounds in water. Another study assessed the fate of these compounds in ion exchange processes. However, these techniques merely transfer PFAS compounds to another compartment, such as the concentrate or regenerate stream. Notably, one presentation highlighted the destruction of PFAS using supercritical water oxidation, though this method was explored on a relatively small scale. 

Two approaches are being explored to reduce the energy consumption of membrane technologies. Firstly, innovative membranes with a higher permeability and improved fouling resistance are being pursued. Examples include scaling up bio-inspired Aquaporin reverse osmosis membranes and full-scale flat sheet ceramic silicon carbide microfiltration membranes with excellent fouling resistance. Secondly, new designs for reverse osmosis systems are being investigated. While some of these designs are currently only examined through mathematical modelling, others are already available as commercial alternative reverse osmosis systems, notably closed-circuit reverse osmosis. Additionally, energy reduction can be achieved through fouling control. A novel fouling monitoring approach developed by a US-based supplier has been adopted by longtime friends from PUB (Public Utility Board, Singapore’s National Water Agency).

Dr. Tao Guihe, Balakrishnan Viswanath and Kiran Kekre (PUB)

Dr. Winson Lay (PUB)

Our presentation on using natural viruses to monitor the integrity of membrane systems took place on the convention’s final day, within the session on emerging approaches for water quality monitoring. We introduced a novel virus detection method based on qPCR, which allows for full-scale determination of membrane integrity (Sensitive membrane-integrity monitoring with natural viruses). This method was collaboratively developed with the Microbiology team at KWR and Gertjan Medema. The presentation generated considerable interest and sparked a lively discussion during the session.

Presentation on natural viruses to determine the integrity of full-scale membrane systems

Final discussion in the session on emerging approaches for water quality monitoring Wilbert Menkveld (Nijhuis Saur Industries), Rutwik Shah (Hydrolabs) and Prof. Shane Snyder (Georgia University of Technologies, former director of SMTC)

Log removal value (LRV) drops with the number of fibre breakages

From the decrease in LRV the number of broken fibers can be calculated on full-scale

An exciting week in Singapore drew to a close with concluding remarks from the organisers and the presentation of the poster and presentation awards. Many of the topics covered during the water treatment sessions at the SIWW closely aligned with topics under investigation by the Water Treatment team at KWR, validating the significance and innovative nature of our research direction.