Novel Membranes For Better Wastewater Treatment - Asian Scientist Magazine
AsianScientist (Mar. 1, 2023) — Together with population growth and industrialization, water scarcity tops the list of global problems. One way to alleviate this issue is through wastewater reclamation, with Singapore’s NEWater process setting an excellent example. Unfortunately, industrial-scale processes of wastewater recycling are currently inadequate when considering the goal of future water sustainability.
The most frequently used method of wastewater treatment in textile and tannery industries is nanofiltration, which uses high hydraulic pressure to move water through a membrane while retaining some valuable salts.
However, the high water pressure causes severe membrane fouling, or the deposition of particles onto the membrane surface, which then causes blockage of membrane pores. Because of the clogging, frequent cleaning cycles and membrane replacements are needed. As such, stable operation of the system requires expensive and cumbersome pre-treatment techniques.
Not only is current industrial water recycling inefficient, it is also harmful to the environment.
“The majority of effluent wastes are typically sent for incineration. In theory, we need to spend around 620 kilowatt-hours of energy to incinerate one ton of wastewater stream, equivalent to 266 kilograms of carbon dioxide,” mentioned Associate Professor Zuo Jian of the Food, Chemical and Biotechnology Cluster of the Singapore Institute of Technology (SIT).
With the rising cost of energy and the detrimental ecological impact of current methods, it is imperative to find an alternative solution for wastewater recycling.
Through the collaboration between Associate Professor Zuo and SideStroem Water Technologies (SideStroem), a novel forward osmosis (FO) technology for wastewater treatment has been developed and is being optimized for industrial-scale usage. The project combines the research prowess of SIT—the country’s University of Applied Learning—in membrane filtration and the track record of SideStroem in FO processes.
“Forward osmosis can help to ease issues associated with traditional nanofiltration because it has a low-fouling tendency. FO membranes can retain operational stability even when the wastewater is high-fouling in nature. As such, we can avoid expensive pre-treatment processes,” explained Associate Professor Zuo.
In fact, FO is gaining popularity in industrial wastewater treatment, and for good reason. Unlike nanofiltration, FO does not require external pressure and, thereby, consumes less energy. In addition to its lower fouling tendency, it is also suitable for pressure-sensitive and heat-sensitive solutions.