The Effectiveness of Ceramic Ultrafiltration as a Pre-Treatment for SWRO at TUAS Spring Singapore

SWRO pre-treatment with polymeric MF/UF membranes initially gained a wider acceptance mainly due to its reported superior removal of particulate and colloidal foulants (absolute filtration), low footprint and its benefits in terms of consistent and reliable performance, and operational flexibility. It was hoped that this approach would also solve performance concerns with conventional treatment technology. With experience polymeric membrane filtration has shown that it too can suffer integrity and fouling issues and has a very limited ability to remove easily biodegradable organics associated with algal blooms (AOM), which in most cases are the main culprit for reverse osmosis membrane fouling (Voutchkov, 2017). Therefore, at its present state of development, polymeric MF- and UF technologies do not always offer the most viable and cost-effective solution for saline water pre-treatment. Development and innovation with alternative UF materials has resulted in promising advances to address algal blooms and other problematic fouling material naturally occurring in seawater. In this paper the advantages and feasibility of ceramic membranes and specifically Nanostoneís CM-151TM ceramic ultrafiltration membrane will be presented and discussed through the data of a pilot study at TUAS Singapore in co-operation with Public Utility Board Singapore (PUB). The ceramic membrane is tested in direct filtration mode with an in-line coagulation with FeCl3 (5 ppm Fe3+). Most important temporary conclusions and recommendations are presented from the first months of operation as the studies continue.