●Research Trends and Results

Application of membrane utilization technology tosewage systems
OGOSHI Masashi, HeadFUJII Tsuyako, ResearcherNISHIMURA Shunsuke, Researcher
IGUCHIHitoshi, Guest Research Engineer
Water Quality Control Department, Wastewater and Sludge Management Division(Key words) Maintenance, international standardization, membrane, membrane cleaning, MBR
1. Introduction
Since the development of reverse osmosis
membranes in the United States in the early 1960s,
research has been conducted to develop a variety ofkinds of membranes and to apply separation
technologies using membranes, and at this time, theyare used in a wide range of fields including
manufacturing industries, medical treatment, water
treatment and so on. In the sewage and wastewater
treatment fields in Japan, the first treatment systemusing membranes was introduced in 1988 at a night
soil treatment plant in Gojome Town in Akita
Prefecture. Its application in sewage systems was alittle delayed until, in 2005, the public sewage final
treatment plant in Fukusaki Town in Hyogo Prefecture
was constructed applying a Membrane Bioreactor *1(below called, “MBR”). Since then, the number of
MBR constructed has increased, with a total of 17
plants (including one provisional facility and one
verification trial plant) in operation as of January 2012,
and the increase in the use of the method will speed up
in the future.
2. Intention to apply the technology to sewage
systems
MBR, which has become the international standard
method of applying membrane utilization technology
to sewage systems, is counted on to play the new roleof creating water reuse/use networks intended toestablish sound water cycles, and to add this role tothe original roles of sewage systems, which areensuring public hygiene and preserving public use
water areas. This is a result of the fact that in addition
to the ability of MBR to almost completely remove
suspended solids and bacteria etc. from sewage, itremoves viruses far more effectively thanconventional treatment methods, and that it makes it
easy to transform an existing facility into an advanced
treatment facility.
3. Initiatives taken as part of this research
The NILIM has taken action to expand its use byproviding technical support by, for example, making ageneral evaluation of MBR*1 and by enacting theGuideline to Introduction of Membrane Treatment
Technology to Sewage Systems (First Edition, Second
Edition). At the present time, in order to prepare a
draft MBR maintenance standard, it is collecting
general data concerning facility operation andperforming field surveys and interviews, to clarify thechallenges
tomaintenanceandtostudy
countermeasures. Among these, it is preforming apriority survey of chemical cleaning of membranes,
which is the key to clarifying whether or not MBR
operation should be introduced, because performing
this more efficiently while consuming less power isvital. The results of a past survey*2, have confirmedthat differences between types of membrane andcleaning method etc. have impacts such as temporarily
lowering biological treatment functions. On the otherhand, it suggests that it is possible to reduce this
impact by improving the cleaning method, so in thefuture, specific improvement measures will be studied.
4. International standardization trends
Seven years have passed since the start of activity topromote international standardization of MBR
technology by the EU, but at this time, there is no
surface movement to realize this. MBR has been
introduced not only into industrialized countries, but
into many other countries, and ISO standardization isnow considered to be important. Japan intends watch
trends in Europe while it promotes standardization incooperation with China and Korea, where the MBR
introduction environment is similar to Japan’s, and theNILIM will, in order to participate in this, join acommittee formed by NEDO (New Energy andIndustrial Technology Development Organization).
[Reference]*1. NILIM web site, “Completion of the General Evaluationof MBR –Evaluation as a Method of Sewage Treatment
which can be Applied Nationwide—
http://www.mlit.go.jp/report/press/city13_hh_000100.html*2. Technical Note of the National Institute for Land andInfrastructure Management, No. 654, pp. 71-76.