1. Adesalinationsystemforobtainingfreshwater fromrawwater containing salt by using a reverse osmosis membrane, and comprising 5 an organic matter assimilation treatment unit for miniaturizing organic matter contained in the raw water, a bioactivity treatment unit for reducing organic matter contained in the raw water by utilizing activities of microorganisms, 10 an antimicrobial treatment unit for adjusting a concentration of the microorganisms contained in the raw water, and a reverse osmosismembranetreatmentunit for desalinating the raw water.by the reverse osmosis membrane. 15 2. The desalination system as set forth in claim 1, wherein the bioactivity treatment unit is arranged downstream of the organic matter assimilation treatment unit, and is arranged upstream of the reverse osmosis membrane treatment unit.

3. The desalination system as set forth in claim 1, wherein the 20 antimicrobial treatment unit is arranged downstream of the bioactivity treatment unit, and is arranged upstream of the reverse osmosis membrane treatment unit.

4. The desalination system as set forth in claim 1, wherein the bioactivity treatment unit includes a bioactivity treatment agent which has the microorganisms adhere thereto and reduces the organic matter contained in the raw water by utilizing the activities of the microorganisms.

5. The desalination system as set forth in claim 4, wherein the 5 bioactivity treatment agent is made of natural zeolite.

6. The desalination system as set forth in claim 1, wherein the antimicrobial treatment unit includes a microorganism reduction treatment agent which reduces the concentration of the microorganisms contained in the raw water. 10 7 . The desalination system as set forth in claim 5, wherein the microorganism reduction treatment agent is made of silver-loaded zeolite on which silver compound is loaded.

8. The desalination system as set forth in claim 4 or 5, further comprising 15 an organic concentration measurement unit for measuring a concentration of the organic matter contained in the raw water which has been treated by the bioactivity treatment unit, a first washing condition determination unit for determining whether or not the bioactivity treatment agent can 20 be used repeatedly on the basis of the concentration of the organic matter in the rawwater, wherein the concentration ofthe organic matterismeasuredbytheorganicconcentrationmeasurementunit, l and a first washing water supply unit for supplying washing -46- water to the bioactivity treatment unit according to a determination result by the first washing condition determination unit.

9. The desalination system as set forth in claim 4 or 5, further 5 comprising a microbial biomass measurement unit for measuring an microbial biomass contained in the raw water which has been treated by the antimicrobial treatment unit, a second washing condition determination unit which 10 determines whether or not the microorganism reduction treatment agentcanbeusedrepeatedlyonthebasis ofthemicrobialbiomass in the raw water, wherein the microbial biomass is measured by the microbial biomass measurement unit, and asecondwashingwatersupplyunitforsupplyingthewashing 15 water to the antimicrobial treatment unit according to a determination result by the second washing condition determination unit.

10. A desalination treatment method for obtaining the fresh water from the raw water containing salt by using the reverse 20 osmosis membrane, and comprising a miniaturization treatment step which miniaturizes the organic matter contained in the raw water, a bioactivity treatment step which reduces the organic matter contained in the raw water by utilizing the activities of microorganisms, wherein the raw water has been treated by the miniaturization treatment step, an antimicrobial treatment step which adjusts the concentration of the microorganisms contained in the raw water 5 which has been treated by the bioactivity treatment step, and a reverse osmosis membrane treatment step which desalinates the raw water by the reverse osmosis membrane, wherein the raw water has been treated by the antimicrobial treatment step. 10 11. A desalination system for obtaining fresh water from raw water containing salt by using a reverse osmosis membrane, substantially as hereindescribedwith reference to accompanying drawings and example.

12. A desalination treatment method for obtaining the fresh 15 water from the raw water containing salt by using the reverse osmosis membrane, substantially as herein described with reference to accompanying drawings and example.

{ DESCRIPTION}
{Title of Invention)
DESALINATION SYSTEM AND DESALINATION TREATMENT METHOD
{Technical Field)
5 {OOOl)
The present invention relates to a desalination system and
a desalination treatment method for obtaining fresh water from
sea water or the like by using a reverse osmosis membrane.
{Background Art)
10 {0002)
There has been used more and more the desalination systems
for obtaining the fresh water from the sea water or the like by
using a reverse osmosis membrane (hereinafter, referred to as
a "RO membrane") because the demand for water desalination has
15 been actualized by the global population growth and the rise of
developing countries in recent years. The RO membrane is made
of materials such as cellulose and polyamides. The fresh water
can be obtained by applying a pressure at least two times of the
osmotic pressure of the sea water to the RO membrane, because
20 the RO membrane has water pass through fine pores thereof and
suppresses salt (mainlyNaC1) frompassingthroughthe fine pores
thereof.
{0003)
Meanwhile, inthedesalination systemusingtheROmembrane,
a biofouling is known as a phenomenon of reducing a permeability
of the RO membrane. Non-Patent Document 1 describes that the
biofouling is significantly generated by biopolymer substances
derived from phytoplankton, for example, TEP (Transparent
5 Exopolymer Particles) which contain particularly adhesive
polysaccharides among carbon-containing organic matter.
(0004)
According to Non-Patent Document 2, 60 % to 80 % of organic
matter in the sea water are dissolved organic matter having low
10 m o l e c u l a r w e i g h t l e s s t h a n o r e q u a l t o 1 k D a , andthe lowmolecular
weight dissolved organic matter are substances involved in
production or degradation of microorganisms.
{0005}
When the microorganisms grow proliferously on a membrane
15 surface of the RO membrane, the permeability of the RO membrane
is restricted and the permeation efficiency of the RO membrane
is reduced. The microorganisms live in any sea water and the
microorganisms deposited on the membrane surface of the RO
membrane grow proliferously by being fed with the low molecular
20 weight dissolved organic matter, and generate or facilitate the
biofouling to induce the reduction of permeability of the RO
membrane. Therefore, it is assumedthatthe lowmolecularweight
dissolved organic matter is also involved in the generation of
the biofouling of the RO membrane.
{0006}
As understood fromthe above, a countermeasure against the
biofouling is required for efficient operation of the
desalination system. As the countermeasure against the
5 biofouling, there is a method for suppressing the reduction of
thepermeabilityofthe Romembranebyreducingthe organicmatter
in the sea water on the upstream side of the RO membrane in the
pretreatment stepby filtration with anultrafiltrationmembrane
(hereinafter, referred to as a "UF membrane") having a pore
10 diameter in the range of about 0.001 to 0.01 pm (for example,
see FIG. 2 of Patent Document 1).
{0007)
In the conventional pretreatment method, chlorine is added
to feedwater (sea water) which is supplied to the RO membrane
15 as a sterilant for the microorganisms in the sea water, and after
a flocculant (for example, aluminum sulfate) is added to the
feedwater if necessary, fouling substances are removed fromthe
feedwater by a filtration apparatus, and then a reductant (for
example, sodium hydrogen sulfate) is added to the feedwater to
20 prevent the deterioration due tothe oxidation ofthe ROmembrane
by chlorine (for example, see FIG. 3 of Patent Document 1).
{Citation List)
{Patent Literature}
{0008)
{Patent Document I}
Japanese Patent Application Publication No. 2010-516450
{Non-Patent Literature)
(0009)
5 {Non-Patent Document 1)
KazuhisaTakeuchi, "Pretreatmentof sea water andmembrane
fouling - Ion exchange membrane and reverse osmosis membrane -
Pretreatment of sea water desalination with RO membrane and
fouling", Bulletin of the Society of Sea Water Science, Japan,
10 2009, Vol. 63, No. 6, pp. 367-371
{Non-Patent Document 2)
Hiroshi Ogawa, "Dissolved organic matter in water
environment - Dynamics of dissolved organic matter in marine",
Journal of Japan Society on Water Environment", 2011, Vol. 34,
15 No. 5, pp. 130-133
{Summary of Invention)
{Technical Problem}
{OOlO}
There is a problem that the organic matter in the sea water
20 cannot be removed completely even by the pretreatment step with
the UF membrane and the reduction of the permeability of the RO
membrane bybiofouling cannotbeprevented. Especially, the low
molecular weight dissolved organic matter cannot be removed
sufficiently from the sea water by the UF membrane.
Permeating the feedwater through the RO membrane after
sterilizing the feedwater to the RO membrane is considered as
one of the countermeasures against the biofouling by the
5 microorganisms, but the method is limited to drinking water and
the like. Inotherwords, it is not desirable toaddthe sterilant,
the reductant, and the like to the feedwater for the purpose of
merely suppressing the biofouling by the microorganisms in the
case of industrial water (for example, fresh water for cooling
10 in a power plant) which is not for drinking, because the fresh
water production cost (running cost) increases.
(0012)
When chlorine is added to the feedwater to the RO membrane,
trihalomethaneis generatedbychemicalreactionwiththeorganic
15 matter inthe feedwater. Sincetrihalomethanecannotbeexcluded
completely from the feedwater by the RO membrane, a part of
trihalomethane is permeated through the RO membrane and can
contaminate the freshwaterproducedbythe desalination system.
(0013)
20 Since most RO membranes have a very limited resistance for
an oxidizing agent such as chlorine, dechlorinationis performed
to prevent the deterioration due to the oxidation of the RO
membrane by adding the reductant to the feedwater. However, the
microorganisms growproliferously again because oxidizing power
in the feedwater is reduced after adding the reductant to the
feedwater, and the microorganisms themselves or their
metabolites adhere to the RO membrane to generate or facilitate
the biofouling. This can result in reducing the permeability
5 of the RO membrane.
{0014}
The objective of the present invention is to provide a
desalination system and a desalination treatment method which
suppress the biofouling of the reverse osmosis membrane as well
10 as suppressing thedeteriorationofthe reverseosmosismembrane.
{Solution to Problem}
{0015}
~osolvetheaboveproblems,t hepresent inventionprovides
a desalination system for obtaining fresh water from raw water
15 containing salt by using a reverse osmosis membrane, and
comprising an organic matter assimilation treatment unit for
miniaturizing organic matter contained in the raw water, a
bioactivitytreatmentunit for reducing organicmatter contained
in the raw water by utilizing activities of microorganisms, an
20 antimicrobial treatment unit for adjusting a concentration of
the microorganisms contained in the raw water, and a reverse
osmosis membrane treatment unit for desalinating the raw water
by the reverse osmosis membrane.
{0016}
To solve the above problems, the present invention further
provides a desalinationtreatmentmethod for obtainingthe fresh
water from the raw water containing salt by using the reverse
osmosis membrane, and comprising a miniaturization treatment
5 step which miniaturizes the organic matter contained in the raw
water, a bioactivity treatment step which reduces the organic
matter contained in the raw water by utilizing the activities
of microorganisms, wherein the raw water has been treated by the
miniaturization treatment step, an antimicrobial treatment step
10 which adjusts the concentration of the microorganisms contained
in the raw water which has been treated by the bioactivity
treatment step, and a reverse osmosis membrane treatment step
which desalinates the raw water by the reverse osmosis membrane,
wherein the raw water has been treated by the antimicrobial
15 treatment step.
{Advantageous Effects of Invention}
{0017)
According to the present invention, the desalination
system and the desalination treatment method which suppress the
20 biofoulingofthe reverse osmosismembrane as well as suppressing
the deterioration of the reverse osmosis membrane can be
provided.
{Brief Description of Drawings)
(0018)
FIG. 1 i s ablockdiagramof a s e a w a t e r d e s a l i n a t i o n system
according t o an embodiment of the present invention.
FIG. 2 i s a g r a p h s h o w i n g a v a r i a t i o n o f s u g a r c o n c e n t r a t i o n
with respect t o water flowing time, comparing p r e t r e a t e d water
5 and bioactive t r e a t e d water.
FIG. 3 is a graph showing a v a r i a t i o n of concentration of
ATP and f r e e ATP with respect t o water flowing time, comparing
the p r e t r e a t e d water, the bioactive t r e a t e d water, and
antimicrobial t r e a t e d water.
10 FIG. 4 i s a g r a p h s h o w i n g a v a r i a t i o n o f f l o w r a t e o f r e v e r s e
osmosismembranetreatedwaterwith respect t o w a t e r flowing time,
comparing the sea water d e s a l i n a t i o n system according t o the
present embodiment witha seawaterdesalinationsystemaccording
t o a comparative example.
15 FIG. 5 is a block diagram of the sea water d e s a l i n a t i o n
system according t o the comparative example.
{Description of Embodiments)
Hereinafter, an embodiment for performing the present
20 invention ( h e r e i n a f t e r , r e f e r r e d t o as a "present embodiment")
1 w i l l be explained i n d e t a i l with reference t o the appropriate
I drawings. In each drawing, the same members a r e denoted by the
same reference signs, andtheduplicatedexplanationthereofwill
1 be omitted.
{0020)
<>
FIG. 1is ablockdiagramof a seawater desalination system
5 S according to the present embodiment. The sea water
desalination system S according to the present embodiment is a
system for obtaining reverse osmosis membrane treated water 15
as fresh water from raw water 10 as sea water (or brine water)
by removing salt and the like by using a RO membrane (reverse
10 osmosis membrane treatment apparatus 5 described later). For
this purpose, the sea water desalination system S includes a
contaminant removal apparatus 1, an organic matter assimilation
treatment apparatus 2, a bioactivity treatment apparatus 3, an
antimicrobial treatment apparatus 4, a reverse osmosis membrane
15 treatment apparatus 5, a treated water component analysis
apparatus 6, and a backwash apparatus 7.
(0021)
The raw water 10, which is the sea water, supplied to the
contaminant removal apparatus 1 is treated to remove
20 comparatively large contaminants in the contaminant removal
apparatus 1, and supplied to the organic matter assimilation
treatment apparatus 2 as contaminant removed raw water 11. The
contaminant removed raw water 11 supplied to the organic matter
assimilation treatment apparatus 2 is treatedtominiaturizethe
organic matter in the contaminant removed raw water 11 in the
organic matter assimilation treatment apparatus 2, and supplied
to the bioactivitytreatment apparatus 3 as pretreated water 12.
5 Additionally, a part of the pretreated water 12 is supplied to
thetreatedwatercomponentanalysisapparatus 6. Thepretreated
water 12 supplied to the bioactivity treatment apparatus 3 is
treated to reduce the organic matter in the pretreated water 12
by decomposing organicmatter byutilizingthe activities ofthe
I
I 10 microorganisms while activating microorganisms in the
1 bioactivity treatment apparatus 3, and supplied to the
antimicrobial treatment apparatus 4 as bioactive treated water
13. Additionally, a part of the bioactive treated water 13 is
supplied to the treated water component analysis apparatus 6.
15 The bioactive treated water 13 supplied to the antimicrobial
treatment apparatus 4 is treated to reduce the microorganisms
in the bioactive treated water 13 in the antimicrobial treatment
apparatus 4, and supplied to the reverse osmosis membrane
treatment apparatus 5 as antimicrobial treated water 14.
20 Additionally, a part of the antimicrobial treated water 14 is
suppliedtothe treatedwater component analysis apparatus 6 and
the backwash apparatus 7. The antimicrobial treated water 14
I . supplied to the reverse osmosis membrane treatment apparatus 5
I
is treatedbythe reverse osmosismembrane in the reverse osmosis
membrane treatment apparatus 5, and divided into the reverse
osmosis membrane treated water 15 as the fresh water and
concentrated waste water 16 which is concentrated with the salt
and the like.
5 I00221
The sea water desalination system S is provided with the
treated water component analysis apparatus 6 and the backwash
apparatus 7 as apparatuses which make functions of the sea water
desalinationsystemSworkproperly. Thetreatedwatercomponent
10 analysis apparatus 6 includes an organic concentration
measurement apparatus 61 and a microbial biomass measurement
apparatus 62. The backwash apparatus 7 includes a washing
condition calculation apparatus 71 and a washing water supply
apparatus 72. The washing condition calculation apparatus 71
15 calculates a washing condition of each treatment apparatus
(bioactivity treatment apparatus 3, antimicrobial treatment
apparatus 4), and the washing water supply apparatus 72 supplies
washing waters 17a and 17b, respectively, to the bioactivity
treatment apparatus 3 and the antimicrobial treatment apparatus
20 4, to wash each treatment apparatus.
I00231
Next, each part (each apparatus) of the sea water
desalination system S will be explained.

filtration treatment apparatus which removes relatively large
contaminants, and removes, for example, foreign substances
1 and/or turbidity components in the size of 1 pm to 100 pm from
5 the raw water 10 which is the sea water. As the contaminant
removal apparatus 1, for example, natural precipitation, a
membrane having many holes with diameter in the range of 1 pm
to 100 pm, or the like can be used.
(0024)
10 < Organic matter assimilation treatment apparatus 2>
The organic matter assimilation treatment apparatus 2 is
an apparatus which miniaturizes the organic matter in the
contaminant removed raw water 11 so that the organic matter can
be easily assimilated by the microorganisms in the bioactivity
15 treatment apparatus 3 which is arrangeddownstreamofthe organic
matter assimilation treatment apparatus 2. For example, the
1 organic matter is miniaturized to the organic matter with low
molecular weight less than or equal to 10 kDa. According to the
present invention, the UF membrane having pore diameters in the
20 range of about 0.001 pm to 0.01 pm or the equivalent has an effect
I of miniaturizing the organic matter, as the organic matter
assimilation treatment apparatus 2.
(0025)
1
Thebioactivitytreatmentapparatus 3 i s a n a p p a r a t u s which
reduces t h e amount of t h e o r g a n i c m a t t e r i n t h e p r e t r e a t e d water
1 2 b y a c t i v a t i n g t h e m i c r o o r g a n i s m s w i t h o r g a n i c m a t t e r a s a feed,
while themicroorganisms i n t h e p r e t r e a t e d w a t e r 12 a r e absorbed
5 and bred on a s u r f a c e of a b i o a c t i v i t y treatment agent.
( 0 0 2 6 )
The b i o a c t i v i t y t r e a t m e n t agent has a c o n s t i t u e n t m a t e r i a l
which is, f o r example, mainly composed of n a t u r a l z e o l i t e . The
n a t u r a l z e o l i t e is a mineral which has micro pores, and c o n s i s t s
10 of Na, Mg, A l , S i , Fe, Ca, K, oxygen, and o t h e r c o n s t i t u e n t
elements. Especially, t h e n a t u r a l z e o l i t e used a s t h e
b i o a c t i v i t y t r e a t m e n t a g e n t has d e s i r a b l y a c r y s t a l s t r u c t u r e
belonging t o mordenite system. The microorganisms i n t h e
p r e t r e a t e d water 12 is adhered t o t h e micro pores e x i s t i n g on
15 a s u r f a c e and/or i n s i d e of t h e n a t u r a l z e o l i t e p a r t i c l e s so t h a t
t h e microorganisms can a s s i m i l a t e and decompose t h e organic
matter ( f o r example, t h e TEP (Transparent Exopolymer P a r t i c l e s )
which a r e considered a s t h e o r g a n i c m a t t e r r e l e a s e d by t h e
microorganisms, sugar components which a r e considered a s
20 components of microorganism c e l l s , and t h e l i k e ) d i s s o l v e d i n
t h e p r e t r e a t e d w a t e r 1 2 . Therefore, thebioactivetreatedwater
13 on t h e downstream s i d e o f t h e b i o a c t i v i t y t r e a t m e n t apparatus
3 is e f f e c t i v e i n reducing t h e c o n c e n t r a t i o n s of t h e
, microorganisms, t h e TEP, t h e sugar components, and t h e l i k e .
I00271
The bioactivity treatment apparatus 3 is, for example, a
vertically arranged bioactivity treatment tower which is filled
with the natural zeolite layer, and the pretreated water 12
5 pretreated by the organic matter assimilation treatment
apparatus 2 passes through the zeolite layer downwardly fromthe
top of the bioactivity treatment tower. In this manner, the
o r g a n i c m a t t e r i n t h e p r e t r e a t e d w a t e r 1 2 i s a d h e r e d t o t h e n a t u r a l
zeolite layer so that the amount of the organic matter in the
10 bioactive treated water 13 can be reduced. The microorganisms
naturally existing in the pretreated water 12 remain and breed
in the micro pores of the natural zeolite layer. The
microorganisms in the natural zeolite layer assimilate and
decompose the micro organic matter (low molecular weight
15 dissolved organic matter) in the pretreated water 12 so that the
amount of the micro organic matter (low molecular weight
dissolved organic matter) in the bioactive treated water 13 can
1 be reduced. The bioactivity treatment tower in the bioactivity
treatment apparatus 3 is arranged one or more.
20 {0028)

~ The antimicrobial treatment apparatus 4 is an apparatus
which reduces the microorganisms in the bioactive treated water
13 by a microorganism reduction treatment agent. For example,
the silver-loaded zeolite is desirablyused as themicroorganism
reduction treatment agent. The silver-loaded zeolite is loaded
with silver which has the sterilizing activity and the
antimicrobial activity for the microorganisms.
5 {0029}
The antimicrobial treatment apparatus 4 is, for example,
a vertically arranged antimicrobial treatment tower which is
filled with the silver-loaded zeolite layer, and the bioactive
I treated water 13 treated by the bioactivity treatment apparatus
I 10 3 passesthroughthe silver-loaded zeolite layer downwardly from
I the top of the antimicrobial treatment tower. In this manner,
the microorganisms in the bioactive treated water 13 are
sterilized by the silver so that the microbial biomass in the
antimicrobialtreatedwater14 canbereduced. Theantimicrobial
15 treatment towers forthe antimicrobial treatment apparatus 4 are
arranged desirably in a plurality in parallel so that the
microorganism reduction treatment agent can be washed and
reproduced.
(0030)
20
! The reverse osmosis membrane treatment apparatus 5 is an
I apparatus which separates the antimicrobial treated water 14
treated by the antimicrobial treatment apparatus 4, into the
reverse osmosis membrane treated water 15 as the fresh water and
salt and the like, by using the RO membrane (not shown).
{0031)

The organic concentration measurement apparatus 61 is an
apparatus which analyzes quantitatively at least one of the
concentrations of the organic matter, the TEP, the sugar, TOC
(Total Organic Carbon), and the like, for the pretreated water
10 12 before flowing into the bioactivity treatment apparatus 3 and
the bioactive treated water 13 which has been treated by passing
throughthebioactivitytreatment apparatus 3. In addition, the
organic concentration measurement apparatus 61 can analyze
I quantitatively at least one ofthe concentrations ofthe organic
15 matter, the TEP, the sugar, the TOC, and the like, for the
antimicrobial treated water 14 which has beentreated bypassing
through the antimicrobial treatment apparatus 4. Measurement
result 21 of the organic concentration measurement apparatus 61
is sent to the washing condition calculation apparatus 71 of the
20 backwash apparatus 7.
to0321
I
I As the quantitative analysis of the organic matter
1 concentration, for example, a phenol-sulfuric acid method or a
high performance liquid chromatography method can be used. As
the quantitative analysis ofthe TEP concentration, for example,
anAlcianblue stainingabsorbancemeasurementmethodcanbe used.
As the quantitative analysis of the sugar concentration, for
example, a phenol-sulfuric acid method can be used. As the
5 quantitative analysis of the TOC concentration, for example, a
combustion oxidation method and a wet oxidation method can be
used. In addition, as the quantitative analysis of the organic
matter concentration, the other measurement methods can be used.
{0033)
10
The microbial biomass measurement apparatus 62 is an
apparatus which analyzes quantitatively the microbial biomass,
for the bioactive treated water 13 before flowing into the
15 antimicrobial treatment apparatus 4 and the antimicrobial
treated water 14 which has been treated by passing through the
antimicrobial treatment apparatus 4. In addition, themicrobial
biomass measurement apparatus 62 can analyze quantitativelythe
microbial biomass, for the pretreated water 12 before flowing
20 into the bioactivitytreatment apparatus 3. Measurement result
22 of the microbial biomass measurement apparatus 62 is sent to
the washing condition calculation apparatus 71 of the backwash
apparatus 7.
Whenthemicrobialbiomass is analyzedquantitatively, ATP
(Adenosine Triphosphate) value and free ATP value including the
ATP are quantified by luciferin-luciferase reaction method. In
addition, as the quantitative analysis of the microbialbiomass,
5 the other measurement methods can be used.
(0035)

The washing condition calculation apparatus 71 is
10 constituted by a controller which has a computer and peripheral
circuits, a personal computer, and the like. The washing
condition calculation apparatus 71 can be configured with an
electronic circuit which fulfills at least a part of functions
thereof, but not limited to the configuration if predetermined
15 functions are fulfilled.
I00361
The washing condition calculation apparatus 71 has a
function to determine whether or not the bioactivity treatment
apparatus 3 can be used repeatedly from the measurement result
20 21 which indicates an organic matter reduction performance of
thebioactivitytreatmentapparatus 3 andis sent fromtheorganic
concentration measurement apparatus 61. When the washing
condition calculation apparatus 71 determines that the
bioactivity treatment apparatus 3 cannot be used repeatedly, a
washing command 23 for washing the bioactivity treatment
apparatus 3 is sent to the washing water supply apparatus 72.
The washing water supply apparatus 72 which has been received
the washing command23 suppliesthe washingwater17a for washing
5 the bioactivity treatment apparatus 3 to the bioactivity
treatment apparatus 3. In addition, the washing condition
calculation apparatus 71 can send the washing command 23 for
washing the bioactivity treatment apparatus 3 to the washing
water supply apparatus 72 periodically by timer, so that the
10 washing water supply apparatus 72 can supply the washing water
17a to the bioactivity treatment apparatus 3.
{ 0037 )
The washing condition calculation apparatus 71 also has
a function to determine whether or not the antimicrobial
15 treatment apparatus 4 canbe usedrepeatedly fromthemeasurement
result 22 which indicates a microbial biomass reduction
performance of the antimicrobial treatment apparatus 4 and is
sent fromthe microbial biomass measurement apparatus 62. When
the washing condition calculation apparatus 71 determines that
20 theantimicrobial treatment apparatus 4 cannotbeusedrepeatedly,
the washing command 23 for washing the antimicrobial treatment
apparatus 4 is sent to the washing water supply apparatus 72.
The washing water supply apparatus 72 which has been received
i the washing command23 s u p p l i e s t h e w a s h i n g w a t e r 1 7 b forwashing
the antimicrobial treatment apparatus 4 to the antimicrobial
treatment apparatus 4. In addition, the washing condition
calculation apparatus 71 can send the washing command 23 for
washing the antimicrobial treatment apparatus 4 to the washing
5 water supply apparatus 72 periodically by timer, so that the
washing water supply apparatus 72 can supply the washing water
17b to the antimicrobial treatment apparatus 4.
(0038)
Thewashingwatersupplyapparatus 72isdesirablyprovided
10 with heating unit (not shown) such as a heater, a heat pump, and
the like, which heats the washing water 17a, 17b, because the
washing effect such as dissolution of deposit on the bioactivity
treatment apparatus 3 and the antimicrobial treatment apparatus
4 is increased by using the heated water as the washing water
15 17a, 17b. Here, as the washing water 17a, 17b, the antimicrobial
treated water 14 which has been treated by passing through the
antimicrobial treatment apparatus 4 is used desirably.
(0039)
Next, the operational relationship between the treated
20 water component analysis apparatus 6 (organic concentration
measurement apparatus 61, microbial biomass measurement
apparatus 62) and the backwash apparatus 7 (washing condition
calculation apparatus 71, washingwater supply apparatus 72) will
be explained.
{0040)

With the passage of water flowing time, decomposed deposit
5 of the organic matter, metabolites of the microorganisms, and
the like, increaseinthenaturalzeolitelayerofthebioactivity
treatment apparatus 3, and reduce the organic matter reduction
performance of the natural zeolite. Therefore, the sea water
desalination system S according to the present embodiment is
10 operative to wash the natural zeolite layer of the bioactivity
treatment apparatus 3 for maintaining the organic matter
reduction performance by maintaining the bioactivity of the
bioactivity treatment apparatus 3.
{0041}
15 The organic concentration measurement apparatus 61
measures over time (continuously with time) the organic matter
concentration in the bioactive treated water 13 which has been
treated by the bioactivity treatment apparatus 3. The
measurement result 21ofthe organicmatter concentration in the
20 bioactive treated water 13 is sent to the washing condition
calculation apparatus 71 from the organic concentration
measurement apparatus 61.
(0042)
The washing condition calculation apparatus 71 determines
whether or not the measurement result 21 (organic matter
concentration in the bioactive treated water 13) is larger than
or equal to a predetermined threshold value CI3. Here, the
predetermined threshold value CI3 is a reference value for
5 determiningwhetherornotitisnecessarytowashthebioactivity
treatment apparatus 3 to restore the bioactivity performance of
the microorganisms.
(00431
When the measurement result 21 is less than the
10 predetermined threshold value CI3, the washing condition
calculation apparatus 71 determines it is not necessary to wash
the bioactivity treatment apparatus 3. On the other hand, when
the measurement result 21 is larger than or equal to the
predetermined threshold value C13, the washing condition
15 calculation apparatus 71 determines it is necessary to wash the
bioactivitytreatment apparatus 3, and sends the washing command
23 which instructs the washing of the bioactivity treatment
apparatus 3tothewashingwatersupplyapparatus 72. Thewashing
water supply apparatus 72 which has been received the washing
20 command 23 which instructs the washing of the bioactivity
treatment apparatus 3 sends the washing water 17a to the
bioactivity treatment apparatus 3. As a consequence, the
bioactivity treatment apparatus 3 is washed to restore the
natural zeolite layer.
(0044)

With the passage of water flowing time, decomposeddeposit
5 of the organic matter, metabolites of the microorganisms, and
the like, increase in the silver-loaded zeolite layer of the
antimicrobial treatment apparatus 4, and reduce the
microorganismreductionperformanceofthesilver-loadedzeolite
layer. Therefore, the sea water desalination systems according
10 to the present embodiment is operative to wash the silver-loaded
zeolite layer of the antimicrobial treatment apparatus 4 for
maintaining the microorganism reduction performance of the
antimicrobial treatment apparatus 4.
I00451
15 The microbial biomass measurement apparatus 62 measures
over time (continuously with time) the microbial biomass in the
antimicrobial treated water 14 which has been treated by the
antimicrobial treatment apparatus 4. The measurement result 22
of the microbial biomass in the antimicrobial treated water 14
20 is sent to the washing condition calculation apparatus 71 from
the microbial biomass measurement apparatus 62.
I00461
The washing condition calculation apparatus 71 determines
whether or not the measurement result 22 (microbial biomass in
the antimicrobial treated water 14) is larger than or equal to
a predetermined threshold value B14. Here, the predetermined
threshold value B14 is a reference value for determining whether
or not it is necessary to wash the antimicrobial treatment
5 apparatus 4 to restore the microorganism reduction performance,
and is set apart from the threshold value C13 for determining
whether or not to wash the bioactivity treatment apparatus 3
described above.
I00471
10 When the measurement result 22 is less than the
predetermined threshold value B14, the washing condition
calculation apparatus 71 determines it is not necessary to wash
the antimicrobial treatment apparatus 4. On the other hand, when
the measurement result 22 is larger than or equal to the
15 predetermined threshold value B14, the washing condition
calculation apparatus 71 determines it is necessary to wash the
antimicrobial treatment apparatus 4, and sends the washing
command 23 which instructs the washing of the antimicrobial
treatment apparatus 4 to the washing water supply apparatus 72.
20 The washing water supply apparatus 72 which has been received
the washing command 23 which instructs the washing of the
antimicrobial treatment apparatus 4 sends the washing water 17b
to the antimicrobial treatment apparatus 4. As a consequence,
1 the antimicrobial treatment apparatus 4 is washed to restore the
silver-loaded zeolite layer.
(0048)
<>
5 The operation and advantageous effects of the sea water
desalination system S (see F I G . 1) according to the present
embodiment will be explained in comparison with a sea water
desalination system Sc (see F I G . 5 described later) according
to a comparative example.
10 {0049)

First, each part (each apparatus) of the sea water
desalination system S (see F I G . 1) according to the present
15 embodiment was configured as follows.
(0050)
The foreign substances and/or turbidity components were
removed from the raw water 10 by using the contaminant removal
apparatus 1.
20 (0051)
The organic matter assimilation treatment apparatus 2
permeated the contaminant removed raw water 11 at a permeation
flow rate 1 m/d by using a UF membrane for permeation of 50 kDa
molecular weight.
0
(0052)
As a raw material of the bioactivity treatment agent of
I the bioactivity treatment apparatus 3, the natural zeolite
(product name: Nitto zeolite ZO mass 15-30) by Nitto Funka Kogyo
5 Co., Ltd. was crushed and classified by size. The classified
zeolite particles having diameters in the range of 0.85 mrn to
2.4 mm were used for the bioactivity treatment agent of the
bioactivitytreatmentapparatus 3. The crystal structure ofthe
zeolite used forthe bioactivitytreatment apparatus 3 is mainly
10 mordenite crystal structure. The advantageous effects of the
present inventionarenot limitedtothe above commercial product
if the bioactivity treatment agent has mainly the mordenite
crystal structure. The column of the bioactivity treatment
apparatus 3 has a cross-sectional area D of 30 cm2, and was filled
15 with the natural zeolite (bioactivity treatment agent) so that
the filled layer height H as an axial length becomes 5 cm. Then
the pretreated water 12 was flowed upwardly from the bottom of
the column at the flow rate Q of 1.5 L/h.
(00531
20 Here, the linear velocity LV and the space velocity SV
inside the column during a water flowing experiment are
calculated by equations (1) and (2), respectively.
LV = Q/D --- (1
SV = LV/H --- (2)
In the present experiment, the linear velocity LV = 50 cm/h
and the space velocity SV = 10 h-l.
(0054)
As a raw material ofthe microorganism reduction treatment
5 agent of the antimicrobial treatment apparatus 4, the natural
zeolite (product name: Nitto zeolite ZOmass 15-30) byNitto Funka
Kogyo Co., Ltd. was crushed and classified by size. The
classified zeolite particles having diameters in the range of
0.85 mm to 2.4 mm were impregnated with silver nitrate aqueous
10 solution which has been added dropwise thereto, and were burned
byheatingintheairsothattheycanbeusedforthemicroorganism
reduction treatment agent of the antimicrobial treatment
apparatus 4. In this manner, the microorganism reduction
treatment agent which has been used for the antimicrobial
15 treatment apparatus 4 is a silver oxide-loaded zeolite, and the
amount of the loaded silver is 5 wt% of the zeolite. The column
ofthe antimicrobial treatment apparatus 4 has a cross-sectional
area D of 30 cm2, and was filled with the silver-loaded zeolite
(microorganism reduction treatment agent) so that the filled
20 layerheight Hasanaxial lengthbecomes 5cm. Thenthebioactive
treatedwater13was flowedupwardly fromthebottomofthe column
at the flow rate Q of 1.5 L/h.
(0055)
The amount of the feedwater (antimicrobial treated water
5 was set to 1.2 L/h. The feed pressure of the feedwater was
set to 7 MPa.
I00561
5
Next, the sea water desalination system Sc according to
I
I the comparative example will be explained. FIG. 5 is a block
I diagram of the sea water desalination system Sc according to the
I
I 10 comparative example. The sea water desalination system Sc
according tothe comparative example is a systemwhich separates
the rawwater 10, which is the seawater, into the reverse osmosis
membranetreatedwater15casthe freshwater andtheconcentrated
I waste water 16c which is concentrated with the salt and the like
15 by using the RO membrane (reverse osmosis membrane treatment
apparatus 5). The sea water desalination system Sc according
1 to the comparative example includes the contaminant removal
I apparatus 1, the organicmatter assimilation treatment apparatus
2, and the reverse osmosis membrane treatment apparatus 5.
20 {0057)
The antimicrobial treated water 14 which has been treated
by the contaminant removal apparatus 1, the organic matter
assimilation treatment apparatus 2, the bioactivity treatment
1 apparatus 3, and the antimicrobial treatment apparatus 4 is
supplied to the reverse osmosis membrane treatment apparatus 5
as the feedwater in the seawater desalination systems according
to the present embodiment. On the other hand, the pretreated
water 12 which has been treated by the contaminant removal
5 apparatus 1 and the organic matter assimilation treatment
apparatus 2 is suppliedtothe reverse osmosismembranetreatment
apparatus 5 in the sea water desalination system Sc according
to the comparative example. The water flow condition and the
configurationofthecontaminantremovalapparatus1, theorganic
10 matter assimilation treatment apparatus 2, and the reverse
osmosis membrane treatment apparatus 5 of the sea water
desalination system Sc according to the comparative example are
the same with those of the sea water desalination system S
according tothe present embodiment, and the explanation thereof
15 will be omitted.
{ 0 0 5 8 }

20 F I G . 2 to F I G . 4 show an example of the results of the water
flow experiment forthe seawater desalination systems according
to the present embodiment (see F I G . 1) and the sea water
desalination system Sc according tothe comparative example (see
F I G . 5).
(0059)
FIG. 2 i s a g r a p h s h o w i n g a v a r i a t i o n o f s u g a r c o n c e n t r a t i o n
with respect to water flowing time, comparing the pretreated
water 12 and the bioactive treated water 13. Here, the
concentration of the sugar (corresponds to uronic acid) having
molecular weight of at least 1 kDa is an analysis item, and
phenol-sulfuric acid method was used with alginic acid of high
purityreagentas a standard substance. The sugar concentration
analysis corresponds tothe quantitative analysis by the organic
concentration measurement apparatus 61 (see FIG. 1).
(0060)
The concentration of the sugar having molecular weight of
at least 1 kDa and the concentration of the total amount of the
organic matter contained in the sea water are considered to have
a positive correlation. Therefore, the sugar concentration
analysis was performed for the sugar having molecular weight of
at least 1 kDa as an indicator showing the organic matter
concentration.
(0061)
As shown in FIG. 2, the bioactive treated water 13 has a
decreased concentration of the sugar having molecular weight of
at least 1 kDa compared to the pretreated water 12, and is
considered to have a decreased concentration ofthe total amount
of the organic matter contained therein. This means that the
sea water desalination system S according to the present
embodiment can decrease the organic matter in the pretreated
water 12 by the bioactivity treatment apparatus 3. It is also
obvious that the antimicrobial treated water 14 obtained by
5 treating the bioactive treated water 13 by the antimicrobial
treatment apparatus 4 has decreased organic matter compared to
the pretreated water 12. As understood from the above, the sea
water desalination system S according to the present embodiment
can decrease the organic matter in the feedwater (antimicrobial
10 treated water 14) to the reverse osmosis membrane treatment
apparatus 5 compared to the organic matter in the feedwater
(pretreated water 12) to the reverse osmosis membrane treatment
apparatus 5 in the sea water desalination system Sc according
to the comparative example.
15 (0062)
FIG. 3 is a graph showing a variation of concentration of
ATP and free ATP with respect to water flowing time, comparing
the pretreated water 12, the bioactive treated water 13, and
antimicrobial treatedwater 14. Here, the concentrations ofthe
20 ATP and the free ATP (hereinafter, collectively referred to as
the "ATP concentration") are analysis items, and the
luciferin-luciferase reaction method was used for the
measurement thereof. The ATP concentration analysis
correspondstothequantitativeanalysisbythemicrobialbiomass
measurement apparatus 62 (see FIG. 1).
(0063)
The ATP is a fundamental component which is always used
in elementary reaction processes of organisms which require
5 energy, andthe ATPvalueis anindicatorofthemicrobialbiomass
in the sea water. The free ATP value is an indicator ofthe amount
of organic matter (traces of existed microorganisms) other than
existing microorganisms including the ATP.
{ 0064)
10 As shown in FIG. 3, the ATP concentration of the pretreated
water 12 was about 0.01 nmol/L on average. On the other hand,
the ATP concentration in the bioactive treated water 13 is 0.06
to 0.08 nmol/L until about 200 hours of water flowing time, and
this means that the bioactivity treatment agent is bioactive in
15 the bioactivity treatment apparatus 3. The antimicrobial
treated water 14 has low ATP concentration compared to the
bioactive treated water 13, and is considered to have decreased
concentration of the microorganisms contained therein. This
means that the sea water desalination system S according to the
20 present invention can decrease the microorganisms in the
bioactive treated water 13 by the antimicrobial treatment
apparatus 4.
I00651
FIG. 4is agraph showingavariationof flowrateof reverse
osmosismembranetreatedwaterwithrespecttowater flowing time,
comparing the sea water desalination system S according to the
present embodiment with the sea water desalination system Sc
according tothe comparative example. The permeation flow rates
5 of the reverse osmosis membrane treated waters 15, 15c as the
permeated water which are permeated through the RO membrane of
the reverse osmosis membrane treatment apparatus 5 are the
indicators showing degrees ofthe biofouling ofthe ROmembranes,
and it means that the biofouling has progressed if a gradient
10 of a decreased variation of the permeated flow rate with respect
to the water flowing time is large.
{0066)
The permeation flow rates of the reverse osmosis membrane
treated waters 15, 15c as the permeated water were calculated
15 by the following formula (3) on the basis of amounts of the
permeated water per unit time and an effective membrane area of
the RO membrane.
[permeation flow rate] = [amount of permeated water
per unit time] / [effective membrane area] --- (3)
20 { 0 0 6 7 )
Thevariationwith time (decreasing speed) ofthepermeated
flow rate according tothepresent embodiment, i.e., the gradient
of the permeation flow rate with respect to the water flowing
time in the present embodiment which is shown by a solid line
in F I G . 4 was -4.5~10-(~m/ d)/ h. On the other hand, the variation
with time (decreasing speed) ofthe permeated flow rate according
tothe comparative example, i.e., the gradient ofthe permeation
flow ratewith respect tothewater flowingtime inthe comparative
5 example which is shown by a dotted line in F I G . 4 was -2.5~10-~
(m/d) /h.
I00681
As shown in F I G . 4, the sea water desalination system S
according to the present embodiment can suppress the biofouling
10 of the RO membrane and suppress the decrease of the permeability
ofthe ROmembrane, compared tothe seawater desalination system
Sc according to the comparative example. Therefore, the sea
water desalination system S according to the present embodiment
can decrease frequencies of a chemical washing and a replacement
15 of the RO membrane, and can extend the life thereof. The sea
water desalination system S according to the present embodiment
can further prevent the RO membrane from being deteriorated by
an oxidizing agent because the chlorine as the oxidizing agent
is not added thereto, while the sea water desalination system
20 S can prevent trihalomethane from being generated by a chemical
reaction of the chlorine with the organic matter.
I00691
As shown in F I G . 3, the microbial biomass (ATP
concentration) in the antimicrobial treated water 14 (feedwater
according to the present embodiment) is high, compared to the
pretreated water 12 (feedwater according to the comparative
example). Nevertheless, as shown in F I G . 4, the sea water
desalinationsystems (according tothepresent embodiment) which
5 uses the antimicrobial treated water 14 as the feedwater can
suppress the biofouling, compared to the sea water desalination
system Sc (according to the comparative example) which uses the
pretreated water 12 as the feedwater. This means that the sea
water desalination system S can decrease sugar having molecular
10 weight lessthanlkDaaswellasthe sugarhavingmolecularweight
of at least lkDa shown in F I G . 2 in the bioactivity treatment
apparatus 3. As described in Non-Patent Document 2, 60 % to 80 %
of the organic matter in the sea water are the organic matter
having low molecular weight less than or equal to 1 kDa, and the
15 lowmolecular weight dissolved organicmatter are the substances
involved in the production or degradation ofthemicroorganisms.
I The sea water desalination system S according to the present
embodiment can remove the low molecular weight dissolved organic
matter less than or equal to 1 kDa, which could not be removed
20 conventionally from the feedwater (antimicrobial treated water
14) supplied to the RO membrane, by the assimilation and the
decompositionbythemicroorganismsinthebioactivitytreatment
apparatus 3, thereby suppressing the biofouling of the RO
membrane.
<>
T h e s e a w a t e r d e s a l i n a t i o n s y s t e m S a c c o r d i n g t o t h e p r e s e n t
embodiment is not limited to the configuration of the above
5 embodiment, and can be modified variously within the scope
without departing fromthe intent ofthe present invention. The
sea water desalination system S according to the present
I embodiment has been explained as the system to obtain the fresh
water (reverse osmosis membrane treated water 15) from the sea
10 water (raw water lo), but is not limited to this. For example,
I
I ~ the desalination systemcan be a brine water desalination system
I
to obtain the freshwater (reverse osmosismembranetreatedwater
15) from the brine water (raw water 10).
{0071)
15 The washing condition calculation apparatus 71 has been
explained as the apparatus which determines whether or not to
washthebioactivitytreatmentapparatus 3bydeterminingwhether
or not the measurement result 21 (organic concentration of the
bioactive treated water 13) is larger than or equal to the
20 predetermined threshold value CI3, but is not limited to this.
For example, the washing condition calculation apparatus 71 can
obtain as the measurement result 21 the organic concentrations
in the pretreated water 12 which is supplied to the bioactivity
treatment apparatus 3 and in the bioactivetreatedwater 13 which
has been treated by the bioactivity treatment apparatus 3 from
the organic concentration measurement apparatus 61. Further,
the washing condition calculation apparatus 71can be configured
to determine a predetermined threshold value C13 12 on - the basis
5 of a threshold value map and a threshold value table which are
set for each organic concentration in the pretreated water 12,
and to determine whether or not the organic concentration in the
bioactive treated water 13 is larger than or equal to the
determined threshold value C13-12. By this configuration, the
10 washing condition calculation apparatus 71 can work even if the
variation ofthe organic concentration in the rawwater10, which
is the sea water, is large.
I0072)
For example, the washing condition calculation apparatus
15 71 can obtain as the measurement result 21 the organic
concentrations in the pretreated water 12 which is supplied to
the bioactivity treatment apparatus 3, the bioactive treated
water 13 which has been treated by the bioactivity treatment
apparatus 3, and the antimicrobial treated water 14 which has
20 been treated by the antimicrobial treatment apparatus 4 from the
organic concentration measurement apparatus 61, and can
determine the predetermined threshold value C13- 1 2 and C14- 1 2 on
thebasis ofthe thresholdvaluemapandthe thresholdvalue table
which are set for each organic concentration in the pretreated
water 12. The washing condition calculation apparatus 71 can
be configured to determine whether or not at least one of the
following conditions is satisfied. One condition is whether or
not the organic concentration in the bioactive treated water 13
5 is larger than or equal to the determined threshold value C13-12r
and the other condition is whether or not the organic
concentration in the antimicrobial treated water 14 is larger
than or equal to the determined threshold value Cl4-1 2. By this
configuration, the washing condition calculation apparatus 71
10 can work even if the variation of the organic concentration in
the raw water 10, which is the sea water, is large. The washing
condition calculation apparatus 71can further determine whether
ornottowashthebioactivitytreatmentapparatus 3bymonitoring
the organic concentration in the antimicrobial treated water 14
15 which is suppliedasthe feedwater tothe reverse osmosismembrane
treatment apparatus 5, thereby suppressing suitably the
biofouling of the RO membrane.
(00731
The washing condition calculation apparatus 71 has been
20 explained as the apparatus which determines whether or not to
wash the antimicrobial treatment apparatus 4 by determining
whether or not the measurement result 22 (microbial biomass in
the antimicrobial treated water 14) is larger than or equal to
thepredeterminedthresholdvalue BI4, but is not limitedtothis.
For example, the washing condition calculation apparatus 71 can
obtain as the measurement result 22 the microbial biomass in the
bioactivetreatedwater13whichis suppliedtothe antimicrobial
I
treatment apparatus 4 and in the antimicrobial treated water 14
5 which has been treated by the antimicrobial treatment apparatus
4 fromthemicrobialbiomassmeasurement apparatus 62. Further,
the washing condition calculation apparatus 71canbe configured I
to determine a predetermined threshold value B14 13 on - the basis
of a threshold value map and a threshold value table which are
10 set for each microbial biomass in the bioactive treated water
13, and to determine whether or not the microbial biomass in the
antimicrobial treated water 14 is larger than or equal to the
determined threshold value BI4-l3. By this configuration, the
washing condition calculation apparatus 71 can work even if the
15 variation of the microbial biomass in the raw water 10, which
is the sea water, is large.
(0074)
For example, the washing condition calculation apparatus
71 can obtain as the measurement result 22 the microbial biomass
20 in the pretreated water 12 which is supplied to the bioactivity
treatment apparatus 3, in the bioactive treated water 13 which
has been treated by the bioactivity treatment apparatus 3 and
is supplied to the antimicrobial treatment apparatus 4, and in
the antimicrobial treated water 14 which has been treated by the
antimicrobial treatment apparatus 4 from the microbial biomass
measurement apparatus 62. Further, the washing condition
calculation apparatus 71 can determine the predetermined
threshold value B14- on the basis of the threshold value map and
5 t h e t h r e s h o l d v a l u e t a b l e w h i c h a r e s e t f o r e a c h m i c r o b i a l b i o m a s s
in the pretreated water 12, and can determine the predetermined
threshold value B14- 1 3 on the basis of the threshold value map and
thethresholdvaluetablewhichare set foreachmicrobialbiomass
in the bioactive treated water 13. The washing condition
10 calculation apparatus 71 can be configured to determine whether
or not at least one of the following conditions is satisfied.
One condition is whether or not the microbial biomass in the
antimicrobial treated water 14 is larger than or equal to the
determined threshold value B14-12r and the other condition is
15 whether or not themicrobialbiomass in the antimicrobial treated
water14 is largerthanor equal tothe determined thresholdvalue
B14-13
I00751
The washing condition calculation apparatus 71 has been
20 explained as the apparatus which determines whether or not to
wash the bioactivity treatment apparatus 3 on the basis of the
measurement result 21 (for example, the organic concentration
of the bioactive treated water 13) by the organic concentration
measurement apparatus 61, but isnot limitedtothis. For example,
the washing condition calculation apparatus 71 can determine
whether or not to wash the bioactivity treatment apparatus 3 by
measuring quantitatively the microbial biomass, the
concentration ofthe microorganisms, the ATP concentration, and
5 t h e l i k e i n t h e b i o a c t i v e t r e a t e d w a t e r 1 3 b y t h e m i c r o b i a l b i o m a s s
measurement apparatus 62. For example, as shown in F I G . 3, it
is determined that the ATP concentration in the bioactivity
treatment apparatus 3 decreases and the bioactivity in the
bioactivity treatment apparatus 3 decreases in the vicinity
10 beyond about 230 hours of the water flowing time. When the
bioactivity in the bioactivitytreatment apparatus 3 decreases,
the performance of the assimilation and the decomposition also
decreases and, as shown in F I G . 2, the organic concentration in
thebioactivetreatedwater13increases. Therefore, thewashing
15 condition calculation apparatus 71 can determine whether or not
to wash the bioactivity treatment apparatus 3 by detecting the
state of the bioactivity in the bioactivity treatment apparatus
3 .
{Reference Signs List)
20 {0076}
S: sea water desalination system (desalination system)
1 : contaminant removal apparatus
2 : organic matter assimilation treatment apparatus (organic
matter assimilation treatment unit)
3: bioactivity treatment apparatus (bioactivity treatment
unit)
4 : antimicrobial treatment apparatus (antimicrobial
treatment unit)
5 5: reverse osmosis membrane treatment apparatus (reverse
osmosis membrane treatment unit)
6: treated water component analysis apparatus
61: organic concentration measurement apparatus (organic
concentration measurement unit)
10 62: microbial biomass measurement apparatus (microbial
biomass measurement unit)
7 : backwash apparatus
71: washing condition calculation apparatus (first washing
condition determination unit, second washing condition
15 determination unit)
72: washingwater supply apparatus (first washing water supply
unit, second washing water supply unit)
10: raw water
11: contaminant removed raw water (raw water)
20 12: pretreated water (raw water)
13: bioactive treated water (raw water)
14: antimicrobial treated water (raw water)
15: reverse osmosis membrane treated water (raw water)
16: concentrated waste water
17a, 17b: washing water
21, 22: measurement result
23: washing command

WE CLAIM:
1. Adesalinationsystemforobtainingfreshwater fromrawwater
containing salt by using a reverse osmosis membrane, and
comprising
5 an organic matter assimilation treatment unit for
miniaturizing organic matter contained in the raw water,
a bioactivity treatment unit for reducing organic matter
contained in the raw water by utilizing activities of
microorganisms,
10 an antimicrobial treatment unit for adjusting a
concentration of the microorganisms contained in the raw water,
and
a reverse osmosismembranetreatmentunit for desalinating
the raw water.by the reverse osmosis membrane.
15 2. The desalination system as set forth in claim 1, wherein the
bioactivity treatment unit is arranged downstream of the
organic matter assimilation treatment unit, and is arranged
upstream of the reverse osmosis membrane treatment unit.
3. The desalination system as set forth in claim 1, wherein the
20 antimicrobial treatment unit is arranged downstream of the
bioactivity treatment unit, and is arranged upstream of the
reverse osmosis membrane treatment unit.
4. The desalination system as set forth in claim 1, wherein the
bioactivity treatment unit includes a bioactivity treatment
agent which has the microorganisms adhere thereto and reduces
the organic matter contained in the raw water by utilizing the
activities of the microorganisms.
5. The desalination system as set forth in claim 4, wherein the
5 bioactivity treatment agent is made of natural zeolite.
6. The desalination system as set forth in claim 1, wherein the
antimicrobial treatment unit includes a microorganism
reduction treatment agent which reduces the concentration of
the microorganisms contained in the raw water.
10 7 . The desalination system as set forth in claim 5, wherein the
microorganism reduction treatment agent is made of
silver-loaded zeolite on which silver compound is loaded.
8. The desalination system as set forth in claim 4 or 5, further
comprising
15 an organic concentration measurement unit for measuring
a concentration of the organic matter contained in the raw water
which has been treated by the bioactivity treatment unit,
a first washing condition determination unit for
determining whether or not the bioactivity treatment agent can
20 be used repeatedly on the basis of the concentration of the organic
matter in the rawwater, wherein the concentration ofthe organic
matterismeasuredbytheorganicconcentrationmeasurementunit,
l and
a first washing water supply unit for supplying washing
-46-
water to the bioactivity treatment unit according to a
determination result by the first washing condition
determination unit.
9. The desalination system as set forth in claim 4 or 5, further
5 comprising
a microbial biomass measurement unit for measuring an
microbial biomass contained in the raw water which has been
treated by the antimicrobial treatment unit,
a second washing condition determination unit which
10 determines whether or not the microorganism reduction treatment
agentcanbeusedrepeatedlyonthebasis ofthemicrobialbiomass
in the raw water, wherein the microbial biomass is measured by
the microbial biomass measurement unit, and
asecondwashingwatersupplyunitforsupplyingthewashing
15 water to the antimicrobial treatment unit according to a
determination result by the second washing condition
determination unit.
10. A desalination treatment method for obtaining the fresh
water from the raw water containing salt by using the reverse
20 osmosis membrane, and comprising
a miniaturization treatment step which miniaturizes the
organic matter contained in the raw water,
a bioactivity treatment step which reduces the organic
matter contained in the raw water by utilizing the activities
of microorganisms, wherein the raw water has been treated by the
miniaturization treatment step,
an antimicrobial treatment step which adjusts the
concentration of the microorganisms contained in the raw water
5 which has been treated by the bioactivity treatment step, and
a reverse osmosis membrane treatment step which
desalinates the raw water by the reverse osmosis membrane,
wherein the raw water has been treated by the antimicrobial
treatment step.
10 11. A desalination system for obtaining fresh water from raw
water containing salt by using a reverse osmosis membrane,
substantially as hereindescribedwith reference to accompanying
drawings and example.
12. A desalination treatment method for obtaining the fresh
15 water from the raw water containing salt by using the reverse
osmosis membrane, substantially as herein described with
reference to accompanying drawings and example.