A practical study of factors that affect forward osmosis experiments

• Main Author: Teo, Jia En.
• Other Authors: Liu Yu
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Environmental engineering::Water treatment
• Online Access: http://hdl.handle.net/10356/40171
• Institution: Nanyang Technological University

Reverse osmosis (RO) can provide ultra pure water but is not an ideal process as high pressure is required to overcome osmotic pressure in sea-water. The high pressure requires large amount of electrical energy and this in turn causes other environmental issues like burning of fossil fuels and pollution. Forward osmosis (FO) on the other hand makes use of concentration gradient between two solutions to induce a net flow of water across a semi permeable membrane. It may be more environmentally friendly and it may have lesser tendency to fouling as compared to reverse osmosis. However FO has its own unique issues like internal concentration polarization and such. The main aim of this study was to investigate FO flux behaviours with different hydrodynamic conditions and different draw solutions. At the same time, the technique of Ultrasonic Time Domain Reflectometry (UTDR) was explored for a quantitative measure of fouling on FO membrane. It was found that factors like fouling, external and internal concentration polarization causes flux performance to decline. Increased draw flow rate increased the flux. However increased feed flow rate decreased flux. Further study can be done to investigate the abnormal phenomenon. UTDR analysis was found not feasible due to the setup and limitations of the equipment. The setup can be modified and a better transducer can be used in future study in order to apply the technique to better investigate membrane fouling effects.