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— Presentation at SIWW 2014 —
July 2, 2014
Singapore International Water Week 2014 (SIWW 2014) was held in Singapore from June 1 to 5. Singapore faces severe problem of safe supply of water because Singapore is a small island nation. Singapore makes efforts to position itself as "the global hydro-hub" to gather and practice the leading-edge techniques for a water technology, and SIWW which held in 2008 at first is a part of its activity. It consisted of Water Convention, Water Expo, Water Cities Summit, and other many events, and attracted more than 20,000 participants from 118 countries. There were about 200 presentations both in poster and oral sessions of Water Convention.
Yokohama Research Laboratory (YRL) made a presentation entitled "Water Quality Evaluation Method for RO Fouling Potential Using Quartz Crystal Microbalance". The developed technology is for a desalination system.
A desalination systems use reverse osmosis membranes to make fresh water from the seawater. Reverse osmosis membrane is a filter to reject ions but to permeate water molecules. Preventing the fouling of the membrane by contaminants (foulants) in the seawater is important requirement for ensuing efficient operation. In the past, the lack of a direct means of detecting foulants in the seawater has instead been identified from pressure increases at the pumps that supply the seawater to the reverse osmosis membranes.
A new method developed by YRL uses QCM (Quartz Crystal Microbalance) to measure the weight of foulants which can be selectively captured by a reverse osmosis membrane material coated sensor (Fig. 1). The new sensing technique had a higher correlation with pressure increase at the pump in laboratory-scale desalination systems than the conventional water quality indices (Fig. 2). We applied the new method to clear what kind of materials was possible foulant and found out some materials can cause severer fouling than a material used for a typical model foulants.
(By NAKANO Keiko)