Nanosun: Sustainable Wastewater Treatment with Nano-Enhanced Membranes

Sustainability and carbon neutrality have emerged as crucial pillars of today’s world. As the global community becomes mindful of the implications of climate change and the well-being of the environment, the urgency for a greener future has never been greater. This also extends to the realm of wastewater treatment, where the imperative to minimize pollution and carbon footprint, and maximize efficiency plays a pivotal role in safeguarding ecosystems and promoting human health.

Industrial wastewater treatment, in particular, warrants special attention due to the complex nature of its contaminants and fluctuation challenges owing to its varying process. Conventional methods struggle to effectively break down toxic and recalcitrant substances, making the treatment process energy-intensive and expensive, and even paint it as “cannot be treated” solidified image. There is a clear need for adaptable and resilient treatment approaches that can effectively address the diverse range of pollutants encountered.

This is where Nanosun steps into the picture.

Nanosun is a Singapore-based company that is anchored in materials and product development when it first started in 2013. This tech startup has Professor Darren Sun at its helm, and his core group students Dr Bai Hongwei, Lucas Zhang, Dr Li Zhengtao, and Tio Wee, who have developed a series of titanium-based microfiltration and ultra-filtration membranes. These form the basis for intellectual property development over the past 10 years. Professor Sun, then a distinguished Shimizu Visiting Professor at Stanford and Wong Ann Chai, MIT-educated Co-Founder, decided to grow the team out from Singapore to raise capital to serve the APAC markets.

Nanosun has been able to make progressive steps in nanomaterials for water-treatment with strong research support from the Economic Development Board, and Capability Development Grants from Enterprise Singapore and PUB. The firm leverages world-class engineering technology and strong partnerships to develop a diverse portfolio of wastewater treatment solutions with a focus on sustainability, resource conservation, and reduced reliance on freshwater resources. Nanosun’s journey in commercialization is guided by redefining problems, reimagining solutions, and reinventing performance. In recognition, Nanosun was awarded Top Emerging Enterprise Award of Singapore and Best Innovation Award of Singapore on seven December 2021 by the Minister of State for Trade and Industry.

Nanosun has made significant in-roads in treating tough industrial wastewater, in particular, and its nano-materials have helped to create solutions to solve recalcitrant COD for discharge.

Nanosun’s best-in-class wastewater management solutions use novel nano-additives to catalyze the breakdown of contaminants and enhance the efficiency and effectiveness of wastewater treatment. The nano-scale nature of the additives allows for a more targeted approach to breaking down the pollutants, which are resistant to conventional treatment methods. With the severity of pollution and the high level of control and mitigation required for industrial wastewater treatment, Nanosun is constantly investing in the advanced oxidation process (AOP) to catalytically oxidize and degrade recalcitrant substances and volatile organic compounds. The innovated technology has successfully transformed the perception of recalcitrant wastewater that cannot be treated into wastewater that can be treated for discharge and even recycling, with many additional benefits such as reduced carbon emission and accelerated sustainable journey to the end user.

One of its key advancements is in redefining the process, and the design and use of 3D-printed, nano-enhanced membranes, which play a vital role in the comprehensive approach to wastewater treatment. These membranes are integrated into the treatment process, enabling effective pre-treatment, precise process control, and efficient oxidation of recalcitrant organic compounds. They facilitate advanced water-pollutant separation that minimizes the strain on freshwater resources and promotes environmental stewardship.

Nanosun can reimagine the solutions to provide highperformance polymers and nano-additives when clients require rapid mixing and sedimentation but do not wish to invest in membrane technology. The proprietary polymers and polymeric solutions are designed to attract and coalesce nano and microparticles for separation, a crucial step in wastewater treatment. These solutions are demonstrated to significantly reduce chemical oxygen demand (COD) in wastewater, from as high as 35,000 to 300,000 milligrams per liter down to the discharge standards of 600 milligrams per liter required in Singapore. This represents a waste removal efficiency of over 95 percent.

3D-PRINTED NANOMEMBRANES – INDUSTRIAL PRODUCTION SCALE

Continuous investment in 3D-printed customized metallic membranes makes Nanosun’s solutions stand out among competitors.

These membranes combine the advantages of conventional polymer and ceramic membranes, resulting in a superior solution that has more flexibility, greater mechanical and chemical strength, and exhibits the super hydrophilic nature of polymer and ceramic membranes.

The layered structure of the membranes is engineered to withstand the corrosive effects of wastewater, and have a lifespan of five to ten years. This durability translates to a cost-effective and attractive solution for clients, extending the effectiveness and minimizing the frequency of replacement.

“We aim to give our customers 360-degree solution in sustainability: lower carbon footprint, longer lifespan, minimized operation expenditures, and smart AI analytics to reduce energy consumption. Our membranes are designed for improving fouling Tio Wee, Application Manager AUGUST - 2023 15 and biofilm formation, while adding AOP to boost reduction of pollutants with minimal use of chemicals.” says Ann Chai Wong, Co-Founder and Managing Director.

Its proprietary 3D printer technology is also used for printing polyvinylidene fluoride (PVDF) polymer, which serves as the industry standard for conventional water filtration membranes. However, Nanosun’s approach revolutionizes the manufacturing process.

Using its advanced 3D printer, Nanosun can print millions of nano-sized PVDF particles per second. These nano-materials are then accumulated on a backing material to create a thin layer membrane sheet. The unique production method significantly increases the membrane’s filtration channels, enhancing its ability to repel pollutants on its surface. It simultaneously allows water molecules to pass through at an accelerated flow rate.
Another crucial aspect of Nanosun’s innovation is the application of transition metals to alter the functional layers of membrane properties. Its patented technology uses titanate to form titanium crystals to enhance the hydrophilic properties of microfiltration and ultrafiltration membranes. At the nano-scale, these membranes can endure rigorous operating conditions, ultimately enabling easy and efficient treatment of recalcitrant industrial wastewater.

By adjusting the thickness and density of PVDF nanofiltration layers, membranes can be tailored for specific filtration purposes, like microfiltration or ultrafiltration. The added layer of customizability ensures optimal performance, as well as costeffectiveness in terms of high recovery rates and low energy consumption. This will drive the advancement of low energy technology for wastewater treatment and seawater desalination to ensure easy access to clean and safe water at an affordable and ultra-low energy consumption rate (such as 2kWh/m3 for seawater desalination or below), especially for fast-developing countries like Singapore.

WATER RECOVERY THROUGH ZERO LIQUID DISCHARGE

Nanosun is currently involved in an ambitious project with the Hong Kong government’s Environmental Protection Department (EPD) to provide a zero-liquid discharge (ZLD) system.

ZLD treats municipal waste, including leachate derived from garbage and food waste. This liquid contains various contaminants like grease, suspended solids, and phosphates. It is treated through a multi-step process, including AOP and ultrafiltration systems, to thoroughly clean it. Through this process, Nanosun recovers nearly 85 percent of the water. While achieving a full 100 percent recovery is challenging, attaining more than 80 percent recovery is considered significant, bringing the process close to the ideal zero discharge.

Building on the success of its inaugural leachate treatment system, Nanosun was privileged to work alongside Keppel Seghers and China Harbour. They collaborated on a project to treat 815 cubic meters/day. This system, set to go live in 2024, utilizes MBR ultrafiltration membrane and AOP with reverse osmosis to achieve zero-liquid discharge, meeting the EPD standards.

LEADING THE SUSTAINABILITY MISSION WITH PROVEN SUCCESS

Nanosun’s innovative membranes have helped many public and private organizations become more sustainable. A notable success story centers on a wastewater treatment system in Singapore that failed to perform to the required standards. The system could not sufficiently purify the water for safe discharge, prompting the client to seek Nanosun’s help.

After being invited to examine the wastewater, the team spent 4 to 5 months gathering and analyzing data. In response, it developed a treatment plant to augment the existing system.

Remarkably, the new addition was only 15 percent of the size of the original plant and effectively addressed the issue, treating over three and a half million tons of water. This marked a significant success for the company, demonstrating its ability to deliver efficient, compact solutions that outperform larger, traditional systems.

In 2022, Nanosun received up to $1 million in co-funding to provide a treatment solution for the Jurong Island Innovation Challenge. During this challenge, it was engaged by a multinational corporation to address high-strength wastewater issues. A pilot project was installed to demonstrate the effectiveness of Nanosun’s solution. This initiative assisted the corporation in reducing its capital and operational costs, and contributed to a decrease in its carbon footprint and increased sustainability. The proposed solution can reduce freshwater intake by up to 50 percent through recycling. In 2022, Nanosun has also successfully treated the DMSO and other similar VOCs (Volatile Organic Compounds) or solvent wastes from semiconductor sectors and petrochemical industry to be non-detectable by its patented technology.

TOWARD A PROMISING FUTURE

Since its inception, Nanosun has been forging a path and charting its own course to success by overcoming obstacles commonly encountered by startups. Even as a small company, it was able to acquire clients by adopting a comprehensive approach to analyzing their needs, proposing solutions, and providing data sets. Using this data, it demonstrated the capacity to treat water, which was instrumental in building confidence among clients. Nanosun also excelled in front-end engineering and ongoing client engagement, along with performance guarantees.
With a successful growth trajectory, Nanosun has designed, commissioned, and delivered water treatment systems and plants for various governments and companies in Singapore, China, the Philippines, and Indonesia. This year, as Nanosun celebrates its 10th anniversary, the company is eager to engage with market development and project management talent in the APAC region and global markets, who can bring boundless energy and innovation to improve product quality, diversify the product range, increase market coverage, and ultimately help the company grow.

Beyond wastewater treatment, Nanosun envisions applying its membrane technology in medical applications, such as kidney dialysis, offering potential cost savings of 40 percent. With further testing and potential FDA approval, this innovation could revolutionize the treatment. The goal is to miniaturize the technology, enabling patients to use it conveniently at home instead of being tied to a dialysis machine at a medical center.

REINVENTING THE WASTEWATER TREATMENT PLANT INTO H₂ ENERGY CENTER

Nanosun is also actively tackling the clean energy crisis by combining industrial wastewater treatment with green H₂ energy production. This initiative curbs the significant clean water consumption associated with hydrogen production. The importance of this initiative is rising by the day as the global water crisis intensifies, with 2.3 billion people currently living in waterstressed regions. Adding to it is the water demand that is set to increase by 55 percent by 2050. Nanosun proposes a remedy to this situation by using municipal sewage treatment plants as sources of clean water. This approach has been successfully applied in Singapore, where municipal wastewater is converted into NEWater, a reliable clean water supply. Adopting this approach, Nanosun not only treats industrial wastewater but also repurposes it for hydrogen production using advanced nanotechnology. This innovative solution addresses and resolves both water and energy crises, promoting a more sustainable and greener future.

In addition to the flatsheet membrane which is used in ZLD and H₂ generation to mitigate water and energy crises, Nanosun has developed a hollow fiber metallic membrane for CO2 capture and storage (CCS) to address climate change. This membranebased CCS technology aligns with the global commitment to combat climate change and helps in meeting the sustainable development goals.

Currently, Nanosun is in an expansion phase and embarking on a Series B funding round, aiming to raise $10 to $15 million USD and to enhance sales channels with more powerful products and solutions. The end goal is to provide solutions and services that draw investment, with a focus on promoting water, energy, and food security. By prioritizing sustainability and striving to achieve carbon neutrality in wastewater management, Nanosun mitigates environmental impacts and contributes to the larger goal of preserving the planet for future generations.