U.S. patent application number 11/329115 was filed with the patent office on 2006-05-25 for water treatment control system using fluorescence analyzer.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Takumi Hayashi, Akira Hiramoto, Kotaro Iyasu, Nobuyoshi Kaiga, Masao Kaneko, Kie Kubo, Futoshi Kurokawa, Seiichi Murayama, Kenji Taguchi, Shojiro Tamaki.
Application Number | 20060108268 11/329115 |
Document ID | / |
Family ID | 18836558 |
Filed Date | 2006-05-25 |
United States Patent
Application |
20060108268 |
Kind Code |
A1 |
Murayama; Seiichi ; et
al. |
May 25, 2006 |
Water treatment control system using fluorescence analyzer
Abstract
A water treatment control system using a fluorescence analyzer
includes an activated carbon injection equipment 4 having an
activated carbon injector 4a, a fluorescence analyzer 7 provided on
the upstream of the activated carbon injector 4a, and a flowing
water flowmeter 6. An activated carbon injection rate necessary to
reduce a trihalomethane formation potential is calculated by an
activated carbon injection rate calculating apparatus 8 based on a
measured value from the fluorescence analyzer 7. An activated
carbon injection amount from the activated carbon injector 4a is
controlled by an activated carbon injection amount control
apparatus 9 based on the activated carbon injection rate and a
measured value from the flowing water flowmeter 6.
Inventors: |
Murayama; Seiichi;
(Kawasaki-Shi, JP) ; Kurokawa; Futoshi; (Tokyo-To,
JP) ; Kaneko; Masao; (Saitama-Shi, JP) ;
Iyasu; Kotaro; (Tokyo-To, JP) ; Taguchi; Kenji;
(Kawasaki-Shi, JP) ; Kubo; Kie; (Chigasaki-Shi,
JP) ; Tamaki; Shojiro; (Tokyo-To, JP) ;
Hiramoto; Akira; (Tokyo-To, JP) ; Hayashi;
Takumi; (Tokyo-To, JP) ; Kaiga; Nobuyoshi;
(Tokyo-To, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Kabushiki Kaisha Toshiba
Tokyo
JP
|
Family ID: |
18836558 |
Appl. No.: |
11/329115 |
Filed: |
January 11, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10640039 |
Aug 14, 2003 |
7014752 |
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11329115 |
Jan 11, 2006 |
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09995764 |
Nov 29, 2001 |
6638421 |
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10640039 |
Aug 14, 2003 |
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Current U.S.
Class: |
210/87 ; 210/101;
210/198.1; 210/259; 210/94 |
Current CPC
Class: |
B01D 61/145 20130101;
B01D 2311/04 20130101; C02F 1/76 20130101; C02F 2209/001 20130101;
C02F 2209/003 20130101; C02F 1/008 20130101; B01D 61/22 20130101;
C02F 1/44 20130101; C02F 2209/40 20130101; C02F 1/52 20130101; C02F
1/444 20130101; B01D 61/147 20130101; B01D 61/16 20130101; C02F
1/283 20130101; Y10S 210/908 20130101; B01D 2311/04 20130101; B01D
2311/16 20130101; C02F 1/78 20130101 |
Class at
Publication: |
210/087 ;
210/094; 210/101; 210/198.1; 210/259 |
International
Class: |
B01D 35/14 20060101
B01D035/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2000 |
JP |
2000-365858 |
Claims
1-9. (canceled)
10. A water treatment control system using a fluorescence analyzer
comprising: a membrane filtration apparatus for separating and
removing a turbid substance in a water to be treated; a
fluorescence analyzer for measuring a relative fluorescence
intensity of the water to be treated; and a membrane filtration
operation control apparatus for operating and controlling the
membrane filtration apparatus based on the measured value of the
fluorescence analyzer.
11. The water treatment control system using a fluorescence
analyzer according to claim 10, wherein the fluorescence analyzer
consists of a pair of analyzers provided on both upstream side and
downstream side of the membrane filtration apparatus, and the
membrane filtration operation control apparatus operates and
controls the membrane filtration apparatus based on the measured
values from the pair of analyzers.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a water treatment control
system using a fluorescence analyzer, including a fluorescence
analyzer, a chlorine agent injection equipment an activated carbon
injection equipment, an ozone treatment equipment, a
coagulation-sedimentation equipment or a membrane filtration
apparatus.
BACKGROUND ART
[0002] In a water treatment facility such as a purification plant,
a precipitation treatment is carried out by introducing a ground
water or surface water as a raw water to a receiving well, and
adding a coagulant in a coagulation-sedimentation equipment to form
flocs. Then, a settled water is passed through a sand filtration
apparatus to remove suspended matters, and finally, conducted a
chlorine treatment for disinfect to supply customers. In order to
ensure an effect of the chlorine treatment for disinfect more
reliably, a intermediate chlorination is performed in which a
chlorine is injected to a sedimentation water at a prechlorination
for injecting a chlorine prior to a coagulant injection point. The
prechlorination is effective in removing an ammonia nitrogen and
microorganisms, or oxidized-removing an iron and manganese in the
raw water. With respect to a raw water having a high trihalomethane
formation potential, it is preferable to adopt a intermediate
chlorination for a reduction of trihalomethane.
[0003] A change-over of the individual chlorine treatments is not
automatically controlled, but is operated by an operator based on
his or her feeling and experience, watching the raw water
quality.
[0004] When the raw water cannot be treated with the usual
treatment because of a deterioration of the raw water quality, a
powdered activated carbon is thrown into the receiving well or the
like so that dissolved matters are absorbed in the activated
carbon. The dissolved matters are removed at a subsequent
coagulation-sedimentation treatment. The thrown amount of the
activated carbon is neither automatically controlled, but is
operated by an operator based on his or her feeling and experience,
watching the raw water quality to decide the thrown amount.
[0005] In a water treatment field, specifically a water
purification treatment, a chlorine treatment is prevalently used
for a disinfect treatment and a removal of iron and manganese, as
stated above. In the case where a trihalomethane precursor is mixed
in a raw water, a trihalomethane is generated by a chlorine
treatment. Since the trihalomethane is a carcinogenic substance,
the generation of trihalomethane must be constrained in a water
treatment process.
[0006] Currently, it is impossible to monitor in an online mode
measurement of trihalomethane and trihalomethane precursor, as it
takes long time and costs money. An ozone treatment and an
activated carbon treatment are effective ones for removing the
trihalomethane precursor. However, there are few treatment plants
having an ozone treatment.
SUMMARY OF THE INVENTION
[0007] The present invention is made in view of the above
disadvantages and has an object to provide a water treatment
control system using a fluorescence analyzer which is capable of
reducing a trihalomethane formation potential, by measuring in an
online mode a relative fluorescence intensity of a raw water or a
water to be treated by a fluorescence analyzer, and controlling,
based on a measured value from the fluorescence analyzer, treatment
processes of an activated carbon injection treatment, a chlorine
agent injection treatment, an ozone injection treatment, a
coagulant injection treatment, or a membrane treatment.
[0008] A water treatment control system using a fluorescence
analyzer of the present invention comprises an injection mechanism
for injecting an impregnating agent to a water to be treated, a
fluorescence analyzer for measuring a relative fluorescence
intensity of the water to be treated, a flowing water flowmeter for
measuring a flow rate of the water to be treated, and a control
apparatus for calculating an impregnating agent injection rate
necessary to reduce a trihalomethane formation potential based on a
measured value from the fluorescence analyzer to control the
injection mechanism based on the impregnating agent injection rate
and the flow rate from the flowing water flowmeter.
[0009] The water treatment control system using a fluorescence
analyzer of the present invention, wherein the injection mechanism
includes an activated carbon injector for injecting an activated
carbon to the water to be treated, and wherein the control
apparatus includes an activated carbon injection rate calculating
apparatus for calculating an activated carbon injection rate
necessary to reduce the trihalomethane formation potential based on
the measured value from the fluorescence analyzer, and an activated
carbon injection amount control apparatus for controlling an
activated carbon injection amount from the activated carbon
injector based on the flow rate from the flowing water flowmeter
and the activated carbon injection rate calculated by the activated
carbon injection rate calculating apparatus.
[0010] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the
fluorescence analyzer consists of a pair of analyzers provided on
both upstream side and downstream side of the activated carbon
injector, and the activated carbon injection rate calculating
apparatus calculates the activated carbon injection rate based on
measured values from the pair of analyzers.
[0011] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the injection
mechanism includes a plurality of chlorine agent injectors for
injecting a chlorine agent to the water to be treated, and wherein
the control apparatus includes a chlorine agent injection equipment
calculation apparatus for selecting an optimum chlorine agent
injector to constrain the trihalomethane formation potential based
on the measured value of the fluorescence analyzer, and for
calculating a chlorine agent injection rate, and a chlorine agent
injection amount control apparatus for controlling a chlorine agent
injection amount from the chlorine agent injector based on the flow
rate from the flowing water flowmeter and the chlorine agent
injection rate calculated by the chlorine agent injection equipment
calculation apparatus.
[0012] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the
fluorescence analyzer is provided on the upstream side of the
chlorine agent injectors.
[0013] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the injection
mechanism includes an ozone treatment equipment having a plurality
of ozone tanks arranged serially, each of which has an ozone
injector for injecting an ozone to the water to be treated, and
wherein the control apparatus includes an ozone injection rate
calculating apparatus for calculating an ozone injection rate to
the respective ozone tanks necessary to reduce the trihalomethane
formation potential based on a measured value of a control
fluorescence analyzer, and an ozone injection amount control
apparatus for controlling an ozone injection amount from the ozone
injectors based on the flow rate from the flowing water flowmeter
and the ozone injection rate calculated by the ozone injection rate
calculating apparatus.
[0014] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the
fluorescence analyzer is provided in at least one of the ozone
tanks.
[0015] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the injection
mechanism includes a coagulant injector for injecting a coagulant
to the water to be treated, and wherein the control apparatus
includes a coagulant injection rate calculating apparatus for
calculating an optimum coagulant injection rate necessary to reduce
the trihalomethane formation potential based on the measured value
of the fluorescence analyzer, and a coagulant injection amount
control apparatus for controlling a coagulant injection amount from
the coagulant injector based on the flow rate from the flowing
water flowmeter and the coagulant injection rate calculated by the
coagulant injection rate calculating apparatus.
[0016] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the
fluorescence analyzer consists of a pair of analyzers provided on
both upstream side and downstream side of the coagulant injector,
and the coagulant injection rate calculating apparatus calculates
the coagulant injection rate based on measured values from the pair
of analyzers.
[0017] The water treatment control system using a fluorescence
analyzer comprises a membrane filtration apparatus for separating
and removing a turbid substance in a water to be treated, a
fluorescence analyzer for measuring a relative fluorescence
intensity of the water to be treated, and a membrane filtration
operation control apparatus for operating and controlling the
membrane filtration apparatus based on the measured value of the
fluorescence analyzer.
[0018] The water treatment control system using a fluorescence
analyzer according to the present invention, wherein the
fluorescence analyzer consists of a pair of analyzers provided on
both upstream side and downstream side of the membrane filtration
apparatus, and the membrane filtration operation control apparatus
operates and controls the membrane filtration apparatus based on
the measured values from the pair of analyzers.
[0019] According to the present invention, the activated carbon
injection rate necessary to reduce the trihalomethane formation
potential is calculated by the activated carbon injection rate
calculating apparatus, based on either of the relative fluorescence
intensity on the upstream side or the downstream side of the
activated carbon injector, so as to control the activated carbon
injection amount by the activated carbon injection amount control
apparatus, based on the activated carbon injection rate calculated
by the activated carbon injection rate calculating apparatus. As a
result, the trihalomethane formation potential can be surely
reduced with a minimum necessary activated carbon injection amount
to be used.
[0020] According to the present invention, an optimum chlorine
agent injection point where the chlorine agent exerts its treatment
effect and constrains the trihalomethane formation potential is
selected, and the chlorine agent injection rate is calculated by
the chlorine agent injection equipment calculating apparatus, based
on a relative fluorescence intensity on the upstream side of the
chlorine agent injector, so as to control the chlorine agent
injection amount by the chlorine agent injection amount control
apparatus, based on the chlorine agent injection rate calculated by
the chlorine agent injection equipment calculating apparatus. As a
result, the trihalomethane formation potential can be surely
reduced with a minimum necessary chlorine agent to be used.
[0021] According to the present invention, an ozone injection rate
to the respective ozone tanks necessary to reduce the
trihalomethane formation potential is calculated by the ozone
injection rate calculating apparatus, based on a relative
fluorescence intensity in one of the plurality of ozone tanks or of
all flowing rate, so as to control an ozone supply amount to the
respective ozone tanks. As a result, the trihalomethane formation
potential can be surely reduced with a minimum necessary ozone to
be supplied.
[0022] According to the present invention, a coagulant injection
rate necessary to reduce the trihalomethane formation potential is
calculated by the coagulant injection rate calculating apparatus,
based on either of the relative fluorescence intensity on the
upstream side or the downstream side of the coagulant injector, so
as to control a coagulant injection amount by the coagulant
injection amount control apparatus, based on the coagulant
injection rate calculated by the coagulant injection rate
calculating apparatus. As a result, the trihalomethane formation
potential can be surely reduced with a minimum necessary coagulant
injection amount to be used.
[0023] According to the present invention, a film can be prevented
from fouling and a term for a chemical cleaning can be extended, by
operating and controlling the membrane filtration apparatus based
on a relative fluorescence intensity of either upstream side or
downstream side of the membrane filtration apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIGS. 1A and 1B are structural charts showing a first
embodiment of a water treatment control system using a fluorescence
analyzer according to the present invention;
[0025] FIG. 2 is a graph showing an example of a relationship of a
relative fluorescence intensity and a trihalomethane formation
potential;
[0026] FIG. 3 is a graph showing an example of a relationship of an
activated carbon injection rate-and a residual rate of a relative
fluorescence intensity (FLr);
[0027] FIG. 4 is a structural chart showing a second embodiment of
a water treatment control system using a fluorescence analyzer
according to the present invention;
[0028] FIG. 5 is a structural chart showing a third embodiment of a
water treatment control system using a fluorescence analyzer
according to the present invention;
[0029] FIG. 6 is a structural chart showing a fourth embodiment of
a water treatment control system using a fluorescence analyzer
according to the present invention; and
[0030] FIG. 7 is a graph showing an example of a relationship of a
chlorine agent injection rate and a reduction rate of a
trihalomethane formation potential.
PREFERRED EMBODIMENT OF THE INVENTION
First Embodiment
[0031] Embodiments of the present invention will be hereinafter
described with reference to the drawings. FIGS. 1 to 3 show a first
embodiment of a water treatment control system using a florescence
analyzer according to the present invention.
[0032] In the first embodiment, in a purification plant (water
treatment facility) having an activated carbon injection equipment,
a desired activated carbon injection amount is calculated based on
a relative fluorescence intensity of a water to be treated, to
achieve a minimum necessary activated carbon injection for a
reduction of trihalomethane formation potential.
[0033] As shown in FIG. 1A, the water treatment control system
according to the present invention includes a receiving well 1 for
receiving a raw water (water to be treated) and a
coagulation-sedimentation equipment 2 for adding a coagulant on the
downstream side of the receiving well 1. The
coagulation-sedimentation equipment 2 removes dissolved polymer
organic matters. A sand filtration apparatus 3 for removing
suspended matters suspending in the water is provided on the
downstream of the coagulation-sedimentation equipment 2.
[0034] In preparation for the case where trihalomethane precursor
can not be reduced by the usual treatment because of a
deterioration of the raw water quality, an activated carbon
injection equipment 4 for injecting an activated carbon from an
activated carbon injector 4a is provided at the receiving well
1.
[0035] As shown in FIG. 1A, a raw water intake port 5 and a
flowmeter (flowing water flowmeter) 6 are disposed on the upstream
of the receiving well 1. The flowmeter 6 measures a flow rate
Q[m.sup.3/h] of the raw water. A fluorescence analyzer 7 for
measuring a relative fluorescence intensity of the raw water is
connected to the raw water intake port 5. An activated carbon
injection rate calculating apparatus 8 is connected to the
fluorescence analyzer 7 for calculating a minimum necessary
activated carbon injection rate for a reduction of trihalomethane
formation potential, based on a measured value of the fluorescence
analyzer 7. An activated carbon injection amount control apparatus
9 is connected to the activated carbon injection rate calculating
apparatus 8.
[0036] The fluorescence analyzer 7 of this embodiment calculates a
fluorescence spectrum with an excitation wavelength of 345 nm, and
calculates an excitation spectrum with a fluorescence wavelength of
425 nm. Thus, a relative fluorescence intensity with a fluorescence
spectrum of 425 nm is calculated.
[0037] In FIG. 1A, the activated carbon injection equipment 4 is
composed of the activated carbon injector (injection mechanism for
injecting an impregnating agent) 4a and control apparatuses 8, 9
including the activated carbon injection rate calculating apparatus
8 and the activated carbon injection amount control apparatus
9.
[0038] An operation of this embodiment as is structured above will
be described. The raw water (water to be treated) flows to be
treated sequentially from the receiving well 1, the
coagulation-sedimentation equipment 2 and the sand filtration
apparatus 3. During this process, the raw water is extracted at the
raw water intake port 5, and then is sent to the fluorescence
analyzer 7.
[0039] A relative fluorescence intensity of the raw water is always
measured by the fluorescence analyzer 7, and is always output to
the activated carbon injection rate calculating apparatus 8 as a
measured value FL1. A relationship of the relative fluorescence
intensity and the trihalomethane formation potential, a
relationship of the activated carbon injection rate and the
residual rate of the relative fluorescence intensity (FLr), and a
control desired value (FLco) of the trihalomethane formation
potential based on the above relationships are included in the
activated carbon injection rate calculating apparatus 8. The
activated carbon injection rate calculating apparatus 8 calculates
an activated carbon injection rate (Drm1) required for the FL1 to
be lower than the Flco to output to the activated carbon injection
amount control apparatus 9.
[0040] FIG. 2 is a graph showing an example of a relationship of
the relative fluorescence intensity and the trihalomethane
formation potential. FIG. 3 is a graph showing an example of a
relationship of the activated carbon injection rate and the
residual rate of a relative fluorescence intensity (FLr) The
activated carbon injection amount control apparatus 9 calculates an
activated carbon injection amount desired value Ps based on the
inputs of a measured value of the flowmeter 6 and the activated
carbon injection rate (Drm1) from the activated carbon injection
rate calculating apparatus 8, and performs an FF (feed forward)
control of the activated carbon injector 4a based on the Ps for
injecting an activated carbon.
[0041] According to the above method, the desired activated carbon
injection rate is calculated by the activated carbon injection rate
calculating apparatus 8 based on the relative fluorescence
intensity of the raw water, and FF controlling of the activated
carbon injection amount is performed. As a result, the activated
carbon injection amount used for reducing trihalomethane formation
potential can be made minimum.
[0042] In FIG. 1A, it may be possible that the
coagulation-sedimentation equipment 2 is provided with a coagulant
injector (injection mechanism for an impregnating agent) 2a, and a
coagulant injection rate calculating apparatus 30a is connected to
the coagulant injector 2a for calculating an optimum coagulant
injection rate for reducing the trihalomethane formation potential,
based on the measured values from the fluorescence analyzer 7 on
the upstream side of the coagulant injector 2a and a fluorescence
analyzer 11a on the downstream side of the coagulant injector 2a. A
signal from the coagulant injection rate calculating apparatus 30a
is sent to a coagulant injection amount control apparatus 30b. The
coagulant injection amount control apparatus 30b controls the
coagulant injector 2a based on the flow rate from the flowing water
flowmeter 6 and the coagulant injection rate from the coagulant
injection rate calculating apparatus. In this case, a coagulant
control apparatus 30 is composed of the coagulant injection rate
calculating apparatus 30a and the coagulant injection amount
control apparatus 30b.
[0043] A membrane filtration apparatus 26 for separating and
removing turbid substances in the water to be treated may be
provided on the downstream side of the sand filtration apparatus 3.
A membrane filtration operation control apparatus 27 may be
connected to the membrane filtration apparatus 26 for operating and
controlling the membrane filtration apparatus 26 based on the
measured values from the fluorescence analyzer 7 and a fluorescence
analyzer 11b on the downstream side of the membrane filtration
apparatus 26.
[0044] In this case, the membrane filtration operation control
apparatus 27 controls automatically and periodically a physical
cleaning time and a cleaning process of the membrane. However, the
membrane filtration operation control apparatus 27 may control a
membrane filtration time, a membrane filtration water amount and a
membrane filtration process, in place of the cleaning time and the
cleaning process.
[0045] As shown in FIG. 1B, the water treatment control system may
include an ozone treatment equipment (injection mechanism for
ozone) having a plurality of serial ozone tanks 20, 21, 22, with
ozone injectors 20a, 21a, 22a, respectively.
[0046] In FIG. 1B, an ozone control apparatus 25 is connected to
each ozone injector 20a, 21a, 22a. The ozone control apparatus 25
is composed of an ozone injection rate calculating apparatus 25a
for calculating an ozone injection rate for the respective ozone
tanks 20, 21, 22 necessary to reduce the trihalomethane formation
potential, based on a measured value of the fluorescence analyzer 7
disposed in the ozone tank 20, and an ozone injection amount
control apparatus 25b for controlling an ozone injection amount
from the ozone injectors 20a, 21a, 22a, based on the ozone
injection rate from the ozone injection rate calculating apparatus
25a and the flow rate from the flowing water flowmeter 6.
Second Embodiment
[0047] A second embodiment according to the present invention will
be described with reference to FIG. 4.
[0048] In the second embodiment shown in FIG. 4, instead of the raw
water intake port 5, a coagulation-sedimentation raw water intake
port 10 is provided on the upstream side of the
coagulation-sedimentation equipment 2, and a fluorescence analyzer
11 for measuring a relative fluorescence intensity of the raw water
is connected to the raw water intake port 10. The rest is
substantially identical with the first embodiment shown in FIGS. 1
to 3. In FIG. 4, the same parts as those of the first embodiment
shown in FIGS. 1 to 3 have the same reference numbers, and their
detailed description are omitted.
[0049] In FIG. 4, the raw water (water to be treated) is extracted
at the coagulation-sedimentation raw water intake port 10, and then
is sent to the fluorescence analyzer 11. A relative fluorescence
intensity of the raw water is always measured by the fluorescence
analyzer 11, and is always output to the activated carbon injection
rate calculating apparatus 8 as a measured value FL2. A
relationship of the relative fluorescence intensity and the
trihalomethane formation potential, a relationship of the activated
carbon injection rate and the residual rate of the relative
fluorescence intensity (FLr), and a control desired value (FLco) of
the trihalomethane formation potential based on the above
relationships are included in the activated carbon injection rate
calculating apparatus 8. The activated carbon injection rate
calculating apparatus 8 calculates an activated carbon injection
rate (Drm2) required for making the FL2 lower than the Flco and
outputs the activated carbon injection rate to the activated carbon
injection amount control apparatus 9.
[0050] The activated carbon injection amount control apparatus 9
calculates an activated carbon injection amount desired value Ps
based on the inputs of a measured value of the flowmeter 6 and the
activated carbon injection rate (Drm2) from the activated carbon
injection rate calculating apparatus 8, and performs an FB (feed
back) control of the activated carbon injector 4a based on the Ps
for injecting an activated carbon.
[0051] According to the above method, the desired activated carbon
injection rate is calculated by the activated carbon injection rate
calculating apparatus 8 based on the relative fluorescence
intensity of the raw water, and FF controlling of the activated
carbon injection amount is performed. As a result, the activated
carbon injection amount used for reducing trihalomethane formation
potential can be made minimum.
Third Embodiment
[0052] A third embodiment will be described with reference to FIG.
5.
[0053] In the third embodiment shown in FIG. 5, both the raw water
intake port 5 and the coagulation-sedimentation raw water intake
port 10 are provided. The fluorescence analyzers 7, 11 for
measuring a relative fluorescence intensity are connected to the
raw water intake port 5 and the coagulation-sedimentation raw water
intake port 10, respectively. The rest is substantially identical
with the first embodiment shown in FIGS. 1 to 3. In FIG. 5, the
same parts as those of the first embodiment shown in FIGS. 1 to 3
have the same reference numbers, and their detailed description are
omitted.
[0054] In FIG. 5, the raw water (water to be treated) is extracted
at the raw water intake port 5 and the coagulation-sedimentation
raw water intake port 10, and is sent to the fluorescence analyzer
7 and the fluorescence analyzer 11, respectively. A relative
fluorescence intensity of the raw water is always measured by the
fluorescence analyzer 7, and is always output to the activated
carbon injection rate calculating apparatus 8 as a measured value
FL1. A relative fluorescence intensity of the raw water to the
coagulation-sedimentation equipment 2 is always measured by the
fluorescence analyzer 11, and is always output to the activated
carbon injection rate calculating apparatus 8 as a measured value
FL2.
[0055] A relationship of the relative fluorescence intensity and
the trihalomethane formation potential, a relationship of the
activated carbon injection rate and the residual rate of the
relative fluorescence intensity (FLr), and a control desired value
(FLco) of the trihalomethane formation potential based on the above
relationships are included in the activated carbon injection rate
calculating apparatus 8. The activated carbon injection rate
calculating apparatus 8 calculates an activated carbon injection
rate (Drm1) required for making the FL1 lower than the Flco,
calculates an activated carbon injection rate (Drm2) required for
making the FL2 lower than the Flco, and outputs the Drm1 and the
Drm2 to the activated carbon injection amount control apparatus
9.
[0056] The activated carbon injection amount control apparatus 9
calculates an activated carbon injection amount desired value Ps
based on the inputs of the measured value of the flowmeter 6 and
the Drm1 and Drm2 from the activated carbon injection rate
calculating apparatus 8, and performs a combination control of an
FF (feed forward) control and an FB (feed back) control of the
activated carbon injector 4a based on the Ps for injecting an
activated carbon.
[0057] In this case, the activated carbon injection amount control
apparatus 9 may adopt one of the Drm1 and Drm2 which is safer,
namely, higher injection rate, or adopt an average value of both
injection rates.
[0058] According to the above method, the desired activated carbon
injection rate is calculated by the activated carbon injection rate
calculating apparatus 8 based on the relative fluorescence
intensity of the raw water, and FF controlling of the activated
carbon injection amount is performed. As a result, the activated
carbon injection amount used for reducing trihalomethane formation
potential can be made minimum.
Fourth Embodiment
[0059] A forth embodiment of the present invention will be
described with reference to FIG. 6. In the fourth embodiment shown
in FIG. 6, in a purification plant having a plurality of chlorine
agent injectors, an optimum chlorine agent injector is selected
based on a relative fluorescence intensity of a flowing water, and
a desired chlorine agent injection amount is calculated to achieve
a minimum necessary chlorine agent injection for a reduction of
trihalomethane formation potential.
[0060] As shown in FIG. 6, the water treatment control system
includes a receiving well 1, a coagulation-sedimentation equipment
2 and a sand filtration apparatus 3. A raw water intake port 5 and
a flowmeter 6 are provided on the upstream side of the receiving
well 1. A fluorescence analyzer 7 is connected to the raw water
intake port 5.
[0061] A chlorine agent injection equipment 14 is provided for
removal of ammonia nitrogen, oxidized-removal of an iron and
manganese in the raw water (water to be treated), and for a
disinfect treatment. The chlorine agent injection equipment 14
includes three types of chlorine agent injectors (injection
mechanism for an impregnating agent), such as a prechlorine
injector 11d positioned at the receiving well 1, an intermediate
chlorine injector 12 positioned at the coagulation-sedimentation
equipment 2 and a post-chlorine injector 13 positioned at the
outlet of the sand filtration apparatus 3.
[0062] A chlorine agent injection equipment calculating apparatus
14a is connected to the fluorescence analyzer 7 for selecting an
optimum injection point for the reduction of trihalomethane
formation potential, and calculating a minimum necessary chlorine
agent injection amount, based on the relative fluorescence
intensity of the raw water. Chlorine agent injection amount control
apparatuses 15a, 15b, 15c are connected to the chlorine agent
injection equipment calculating apparatus 14a, which correspond to
the respective chlorine injectors 11d, 12, 13.
[0063] In FIG. 6, the chlorine agent injection equipment 14 is
composed of the prechlorination injector 11d, the intermediate
chlorination injector 12, the postchlorination injector 13 and the
control apparatuses 14a, 15a, 15b, 15c including the chlorine agent
injection equipment calculating apparatus 14a and the chlorine
agent injection amount control apparatuses 15a, 15b, 15c.
[0064] An operation of this embodiment as is structured above will
be described. The raw water (water to be treated) is extracted at
the raw water intake port 5, and is sent to the fluorescence
analyzer 7. A relative fluorescence intensity of the raw water is
always measured by the fluorescence analyzer 7, and is always
output to the chlorine agent injection equipment calculating
apparatus 14a as a measured value FL1.
[0065] A relationship of the relative fluorescence intensity and
the trihalomethane formation potential, a relationship of the a
desired value of a chlorine agent injection rate and a
trihalomethane formation potential (Cth), and a control desired
value (Cthsv) of a trihalomethane formation potential based on the
relationships are included in the chlorine agent injection
equipment calculating apparatus 14a. The chlorine agent injection
equipment calculating apparatus 14a selects the optimum chlorine
agent injectors 11d, 12, 13 required for making the Cth lower than
the Cthsv, and calculates chlorine agent injection rates (Drm3,
Drm4, Drm5) to output to the chlorine agent injection control
apparatuses 15a, 15b, 15c. FIG. 7 is a graph showing an example of
a relationship of a chlorine agent injection rate and a reduction
rate of a trihalomethane formation potential.
[0066] The chlorine agent injection control apparatuses 15a, 15b,
15c selected by the chlorine agent injection equipment calculating
apparatus 14a, which correspond to the chlorine agent injectors
11d, 12, 13 calculate a chlorine agent injection amount desired
value Psc1, based on the inputs of the measured value of the
flowmeter 6 and the Drm3, Drm4, Drm5 from the chlorine agent
injection equipment calculating apparatus 14a, and perform FF (feed
forward) controlling of the chlorine agent injectors 11d, 12, 13
based on the Psc1 for injecting a chlorine agent.
[0067] According the above method, the of chlorine agent injection
point to be used is selected by the chlorine agent injection
equipment calculating apparatus 14a, based on the relative
fluorescence intensity of the raw water, and the desired chlorine
agent injection rate is calculated to FF control the chlorine agent
injection amount. Thus, the chlorine agent amount to be used can be
made minimum, and removal of ammonia nitrogen, removal of an iron
and manganese, and disinfect treatment can be effectively made, and
the reduction of trihalomethane formation potential can be
achieved.
[0068] As stated above, according to the present invention, a water
treatment system using a fluorescence analyzer measures online a
relative fluorescence intensity of a water to be treated, controls
an injection amount of an activated carbon, a chlorine agent, an
ozone or a coagulant, or operates and controls a membrane
filtration apparatus. Therefore, a reduction of trihalomethane
formation potential, and a constraint of an excessive injection and
an optimum operation control can be achieved.
* * * * *