NAMS 2002 Workshop - ICOM 2008

condition was optimized. Secondly, the investigation was conducted for the
improved Chemical Enhanced Backwashing (CEB) in order to remove more
effectively the organic matters from membrane surface and inside of the micropores.
As a result of the investigations above, the HFU filtration process
achieved the extremely higher flux 167 LMH (4.0 m/d) than before (1.0~1.5 m/d),
which could reduce the operational cost as well as the initial equipment cost. 2)
RO The major difficulty in the RO operation for WWR is the membrane fouling
due to the chemical and biological reasons. In this study, by using some organic
matters measurement in order to correlate the RO feed water composition with
chemical fouling property, it was found the specific organic matters were related
to the chemical fouling. Based on the analyses and comparison of various RO
membranes, it was confirmed that the low fouling RO membrane had the
excellent performance for chemical fouling. As for the bio-fouling, the
bactericides are usually used in order to prevent bio-fouling. However, it is
difficult to select appropriate and effective bactericide dosing conditions. In this
study, we have successfully developed the modified bio-film formation rate (BFR)
technique with more accurate ATP measurement and the newly developed test
column consisting of the actual RO membrane. This technique enabled to obtain
the bio-fouling potentials in shorter time. By using this modified BFR technique,
the bio-fouling potentials of the various RO feed water were easily measured,
and the most effective bactericide dosing condition could be decided.
References
Minegishi, S., Tanaka, Y., Henmi, M., and Uemura, T., 2007, "Advanced Fouling Resistant PVDF
Hollow Fiber Membrane Modules for Drinking Water Treatment ", The 2007 IWA Leading Edge
Conference on Water and Wastewater Technologies, Singapore
Minegishi, S., Henmi, M., Matsuka, N., and Kurihara, M., 2003, "Newly Designed PVDF Hollow
Fiber and Flat Sheet Membrane for Drinking Water Production and Wastewater Reuse ",
ICOM2005, Korea
J.S. Vrouwenvelder, D. van der Kooij, 2001, "Diagnosis, prediction and prevention of biofouling of
NF and RO membranes ", Desalination 139, 65- 71