Vol 33 No 4 Text - International Ozone Association

Ozone News Volume 33, No. 4
Application of Ozone and Ozone Resistant Microfiltration Membranes
for the Reuse of Secondary Effluent
Takuya Onitsuka, Shizuo Takeda
R&D Division of SUIDO KIKO Co., Ltd, 5-48-16 Sakuragaoka Setagaya-ku, Tokyo,156-0054, JAPAN
Abstract
A new reclamation system by combining microfiltration (MF) membrane with ozone was developed
to obtain a better water quality in sewerage reuse. The MF membrane was a hollow fiber made from
polyvinylidenefluoride that has a high ozone resistance. The reclamation system using this MF
membrane together with ozone could provide high filtration flux of 5 m3 /m2. d and a stable operation
without chemical cleaning for long terms. This is because ozone decomposed or denatured a part of
organic materials in the sewerage water and reduced fouling of the membrane surface. The water
obtained by this reclamation system has a high quality and excellent in security against pathogenic
organisms. This system was constructed at Shibaura water reclamation center, bureau of sewerage of
Tokyo Metropolitan Government. The reclamation water of a high grade has been supplied to the
redeveloped area as toilet flush water and cooling water since April 2004.
Keywords
Ozone; Reuse; Reclamation; Ozone Resistant Microfiltration Membrane;
Introduction
The effective usage of water resources and energy in
sewage works is desired and the ability to recycle water is
a priority to assist in the problem of global water
shortage. The secondary effluent from wastewater
treatment plants is a valuable water resource and its reuse
is given priority in this issue. The reclamation water is
used a in variety of applications such as landscape
irrigation, environmental uses, industrial activities,
agricultural irrigation, snow melting use and toilet
flushing etc. In case of water shortage areas and the
redeveloped area in a large city, the use of reclamation
water for environmental uses and toilet flushing is
increasing. It is necessary for these reclamation waters to
have a high quality, as human beings have more
opportunities for being in direct touch with them.
Therefore, bacteria and pathogenic organisms must be
taken into consideration in addition to suspended
matters, color and odor.
Membrane filtration is a solid-liquid separation method
with high performance. There are few instances of
membranes in sewerage reclamation division, as it is likely
to be fouled by the organic matters and a higher cost than
that of other separation methods. Ozone has a strong
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chemical oxidation property. Ozone is expected to
decompose organic materials in the water and reduce a
fouling of the membrane surface. The new reclamation
system using MF membrane together with ozone was
developed and introduced into the sewerage treatment
plant.
Materials and Methods
Figure 1. The flow sheet of the developed reclamation
system