A new type of hollow fiber membrane underpins a novel water treatment system that potentially may reduce toxic waste and associated waste disposal costs by over 90%, says its developers at the National University of Singapore.
The thermoplastic fluoropolymer membrane, invented by Neal Chung, a professor in the department of chemical and biomolecular engineering, has three hollow cores, allowing for a water flow rate that’s about 30% higher than that achieved by other hollow-fiber membranes.
The membrane will feature in a 5,000-L/d pilot plant, which is a joint effort between the Separation Technologies Applied Research and Translation (START) Centre, a national-level facility to develop and commercialize innovative separation and filtration technologies, and Memsift Innovations, a local water technology firm specializing in zero-liquid-discharge water treatment systems.
The pilot plant should start operation in June and run for 18 months. It will get wastewater from a nearby semiconductor facility; if all goes according to plan, the pilot plant will save the company up to 1.6 million L/yr of water and about S$250,000 (≈$184,000) in disposal costs. Currently, the semiconductor maker transports toxic wastewater to an incineration facility.
The pilot process will operate under vacuum at between 50°C and 80°C, notes Memsift founder J. Antony Prince. He believes the tri-bore membrane will help improve the efficiency of the company’s patent-pending Improved Membrane Distillation (IMD) process.
“The TS-30 IMD system… can be operated using low-grade waste heat from industries or solar panels. If there is waste heat available, the operating cost can be significantly reduced — to less than 2.5kW/m3 at a reference capacity of 100 m3/day and above,” he says.
“We still need to optimize the process for the new membrane and cleaning methods need to be established. The data from this pilot study also is intended to help us to find ways to address other unknowns such as membrane lifetime,” explains Prince.
Meanwhile, START already has begun fabricating the tri-bore fiber on an industrial scale (Figure 1).
If the pilot is successful, Memsift will take a full license and commercialize the new membrane system.
“We believe that the 30% increased efficiency of this membrane will bring Memsift more opportunities in the market place,” adds Prince.
Other members of SG-MEM, Singapore’s national membrane consortium, also will have access to the tri-bore membrane for commercial collaborations.