In situ Monitoring Techniques to Characterize Feed Fouling Potential of Reverse Osmosis Operations

Membrane filtration systems are successful methods to make high-quality water. The most challenging problem in membrane related technologies is fouling which decreases the performance and increases the operational costs. The Feed Fouling Monitor as a non-invasive techniques combined with Salt Tracer Response Technique (STRT) was introduced to monitor and detect colloidal and organic fouling in reverse osmosis in this study. An on the Feed Fouling Monitor (FFM), was used to provide online measurement of specific cake resistance of foulant while STRT was used tomeasure directly concentration polarization trends and estimate the contribution of CEOP under constant flux using both organic and inorganic foulant models. The developed mathematical model including both the cake resistance and the CEOP effect due to cakeformation was used to characterize and monitor RO fouling. The results underscore the importance of CEOP in contributing to the increase intransmembrane pressure due to colloidal fouling in RO of saline feeds. It also indicates that the rate of increase in TMP due to the hydraulic cake resistance is approximately linear whereas the CEOP increases exponentially with increasing flux.

Keywords:

Reverse osmosis , Fouling , Feed Fouling Monitor , cake-enhanced osmotic pressure , Ultrasonic Time-Domain Reflectometry , salt tracer response technique