JPH05269309A - Agglomeration processing device - Google Patents

Abstract

(57) [Summary] [Purpose] The amount of flocculant added is controlled to the optimum amount. [Structure] Raw water flows from raw mud pit 1 to piping 3 with pump 2.
And is introduced into the flocculation tank 4. The aggregating tank 4 is provided with a stirrer 5, and a cationic organic aggregating agent is dosed from a chemical dosing device comprising a chemical liquid storage tank 6, a chemical dosing tube 7 and a chemical dosing pump 8. The aggregating treatment liquid from the aggregating tank 4 is sent to a dehydrator (any type of dehydrator may be used as long as it uses an aggregating tank) 9. The dehydrated cake produced in the dehydrator 9 is sent to a cake processing step such as incineration, and the filtrate is sent to the filtrate storage tank 10. The filtrate storage tank 10 includes a thermometer 11, a heat transfer detector 12, an electric conductivity meter 13, and an SS concentration meter 14. The detection signals of these instruments 11, 12, 13, 14 are input to the arithmetic and control unit 16. The arithmetic controller 16 outputs a control signal to the chemical injection pump 8. [Effect] By using the heat transfer detector and the drug saturation indicator factor sensor, it becomes possible to perform accurate drug dosage control so that the drug dosage becomes the optimum amount. Therefore, the excess or deficiency of the drug injection amount is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aggregating treatment device, and more particularly to an aggregating treatment device for controlling a chemical injection amount (addition amount) of an aggregating agent to an optimum amount. More specifically, the present invention relates to an aggregating treatment apparatus suitable for controlling the amount of an organic aggregating agent (hereinafter sometimes referred to as a polymer) added.

[0002]

2. Description of the Related Art Conventionally, various chemical injection control methods have been proposed for sludge dewatering. For example, it has been proposed to indirectly measure the amount of residual polymer in a liquid using a viscometer or the like because the viscosity of the liquid changes as the amount increases, and to perform drug injection control using the measured value as an index. ing.

The physical properties of the liquid include not only the viscosity but also various properties such as specific heat and electric conductivity, which influence each in the chemical injection. Therefore, if the amount of drug injection is controlled using only the viscosity, which is one of the physical properties of the liquid, as an index, the amount of drug injection becomes excessive and deficient, and it is unavoidable that the drug cost increases due to poor aggregation and excessive addition.

Japanese Patent Application No. 1-293358 (Japanese Patent Application Laid-Open No. 2-2
No. 90205), in order to solve such a problem of the prior art, the change in the physical property value of the liquid due to the change in the sludge property etc. is regarded as the change in heat transfer and is used as an index, and the value of the control of the chemical injection amount is controlled by the value. Those that do are proposed.

As shown in FIGS. 5 and 6, the water content of the dehydrated cake and the detection value of the heat transfer detector of the liquid subjected to the agglomeration treatment (or the liquid undergoing the agglomeration treatment) have a close relationship with each other. For example, the water content of the dehydrated cake is minimized by controlling the addition amount of coagulation so that the value detected by using a hot wire anemometer is minimized.

FIGS. 5 and 6 are graphs showing the correlation between the amount of the flocculant (cationic polymer) added, the hot wire anemometer detection value (potential difference) and the dehydrated cake water content when the raw water is sewage mixed raw sludge. ..

As shown in FIG. 5, the coagulant addition amount is about 150-
Around 200 ppm is the minimum range of the detected value of the hot wire anemometer, and at this time, the water content of the dehydrated cake is also the minimum.

FIG. 6 is a similar correlation diagram to the mixed raw sludge different from FIG. 5, but both the detected value of the hot wire anemometer and the dewatered cake are minimum and minimum when the addition amount is about 150 ppm. The same test was repeated for other various types of raw water, but the correlations as shown in Figs. 5 and 6 were clearly recognized in all cases. In addition, it was confirmed that there are similar correlations to the above with respect to characteristics such as cake peelability and filtrate amount other than the cake water content.

The invention of Japanese Patent Application No. 1-293358 was completed on the basis of such findings, and since the chemical injection amount is controlled based on the detection value of the heat transfer detector, the water content of the dehydrated cake is minimized. As a result, it becomes possible to control the drug injection amount.

[0010]

[Problems to be Solved by the Invention] Japanese Patent Application No. 1-29335
In the device of No. 8, the output value of the heat transfer detector is a downwardly convex curve as shown in FIG. 7 (a schematic diagram of the data of FIGS. 5 and 6), which indicates that the dehydration is good. The sensor output is the same in (Point A) and in the state of poor dehydration (Point B),
As a result, there is an inconvenience that special data acquisition and processing (for example, detection of the inclination direction of the tangent line of the curve in FIG. 7) is required to determine the two.

[0011]

A coagulation treatment apparatus of the present invention comprises a chemical injection device for adding a coagulant to a liquid to be coagulated, and a heat transfer detector provided so as to come into contact with dehydrated filtrate. And a controller for controlling the chemical injection amount of the chemical injection device based on the detection value of the heat transfer detector, and detecting the chemical injection saturation indicator factor of the dehydrated filtrate or dehydrated cake in a coagulation treatment device. A sensor is provided, and the control device controls the chemical injection amount based on the detection values of the heat transfer detector and the sensor.

[0012]

In FIG. 7, the region to the right of the minimum point (for example, point A) is the region where the dose is excessive, and the dehydration property does not improve even if the dose is increased further. ,
That is, the drug injection effect has reached a saturated state.

In the saturated range of the chemical injection, the coagulant excessively present in the liquid causes the dehydrated filtrate or the dehydrated cake to have an increased foaming property and an increased stickiness of the cake due to the excessive amount of the chemical injection.

In the present invention, an agent that causes such an excessive drug injection phenomenon (hereinafter, referred to as an agent injection saturation indicator).
Is detected, and this drug injection saturation indicator is also used for drug injection control.

Since this drug injection saturation indicator has extremely different detection values in the region on the right side and the region on the left side of the minimum point in FIG. 7, this drug saturation factor is detected. As a result, it is possible to accurately identify whether the detection value of the heat transfer detector is on the left or right of the minimum point in FIG. Therefore, according to the present invention, it is extremely easy to control the dose to be the value at the minimum point in FIG.

[0016]

EXAMPLES Examples will be described below with reference to the drawings.

FIG. 1 is a system diagram of a coagulation treatment apparatus according to an embodiment. Raw water is a raw mud pit 1 to a pipe 3 with a pump 2.
And is introduced into the flocculation tank 4. The aggregating tank 4 is provided with a stirrer 5, and a cationic organic aggregating agent is dosed from a chemical dosing device comprising a chemical liquid storage tank 6, a chemical dosing tube 7 and a chemical dosing pump 8. The aggregating treatment liquid from the aggregating tank 4 is sent to a dehydrator (any type of dehydrator may be used as long as it uses an aggregating tank) 9. The dehydrated cake produced in the dehydrator 9 is sent to a cake processing step such as incineration, and the filtrate is sent to the filtrate storage tank 10.

The filtrate storage tank 10 comprises a thermometer 11, a heat transfer detector 12, an electric conductivity meter 13, and an SS concentration meter 14.

The detection signals of these measuring instruments 11, 12, 13, 14 are input to the arithmetic and control unit 16. The arithmetic controller 16 outputs a control signal to the chemical injection pump 8. The pump 8 is inverter-controlled, for example.

The heat transfer detector referred to in the present invention is a commonly used heat ray or hot film type anemometer,
A device capable of detecting heat transfer such as a heat transfer coefficient meter can be used.

Also, other than this, it is applicable as long as it has a self-heating source for energizing and heating a heater, or a heating source for indirectly heating by a heater such as a combination of a heater and a thermometer. It is possible.

The present invention will be described below by using a hot wire anemometer.

As is well known, the hot wire anemometer is one in which a constant current is passed through a hot wire to be a heating body and the hot wire is inserted into a fluid. When the flow velocity fluctuates, the degree of heat removal from the heat rays changes. As a result, the temperature of the heating wire changes and the resistance also changes. The hot-wire anemometer measures the flow velocity by catching this change in resistance as a change in voltage.

The present invention utilizes the principle of this hot-wire anemometer, and further provides a condition under which the flow velocity of the liquid is constant, and on the other hand, minute movement of heat deprived from the heat rays is resisted (voltage).
It is to be understood as a change in the physical properties, and this change is grasped as a change in the physical properties. Therefore, the filtrate storage tank 10 has a stirrer 17
In addition, an overflow pipe 15 for obtaining a constant water level is provided in order to keep the stirring conditions the same while always rotating at the same speed during measurement.

FIG. 8 is a schematic diagram of the hot wire anemometer 12 used in this embodiment. The hot wire anemometer 12 includes a hot wire (resistance) 12a, a constant current generator 12b, and a voltmeter 12c.

The heating wire 12a is in contact with the liquid that swirls in the filtrate storage tank 10 at a constant flow rate, and when this liquid has a constant physical property, the amount of heat taken away from the heating wire 12a is constant when a constant current is applied. , The resistance is constant and the voltage is not changed. When the physical properties of the liquid change, the amount of heat taken from the heating wire 12a changes, so the resistance changes. That is, heat is transferred from the heat ray into the liquid and the resistance changes. Now, since the current is made to flow constant, this change in resistance can be grasped as a change in voltage, and this change becomes the detected value of the physical property value in the liquid. The change in the characteristic value of the heating wire 12a may be detected by either the change in the resistance value or the change in the voltage.

Although the constant current type has been described above, a constant temperature type hot wire anemometer may be used.

As is clear from the above, by using the hot-wire anemometer as in the present invention, it is possible to catch a minute change in the physical property value only by giving a constant flow velocity.

In the apparatus of FIG. 1 thus constructed, the raw water is subjected to the coagulation treatment in the coagulation tank 4 by the addition of the coagulant, and the addition amount at this time is the flow rate of the heat rays detected in the filtrate storage tank 10. It is considered to be the drug injection amount at which the total detected value is minimal.

This control method will be described with reference to FIG.

In FIG. 2, the detected value of the hot wire anemometer 12 has a minimum at the optimum addition amount N. The detection value of the SS densitometer 14 decreases monotonously until the amount of N added increases with the increase of the chemical injection amount, but when N is the inflection point and exceeds it, it does not decrease any further. This is the saturation value).

Therefore, by referring to the detection value of the SS densitometer 14 when the detection value of the hot wire anemometer 12 is a value, the optimum addition amount N at the minimum point is the chemical injection amount at that time.
It is possible to determine whether there is more or less than. If the detected value of the SS densitometer 14 is larger than b, the drug injection amount is increased. If the detection value of the SS densitometer 14 is smaller than b, the dose of medicine is decreased. As a result, it is possible to easily control the dose to be brought close to N.

Even after the optimum addition amount N is reached, there is a possibility that the optimum addition amount N itself may change due to changes in the state of raw water. Therefore, even after the dose has reached N, it is possible to change the dose according to the detection values of the hot wire anemometer 12 and the SS densitometer 14.

In the apparatus shown in FIG. 1, the detected values of the thermometer 11 and the electric conductivity meter 13 are also input to the arithmetic controller 16, which are in the form of raw water (temperature, soluble salt concentration, etc.).
If there is a change in the hot wire anemometer, the detected value of the hot wire anemometer will fluctuate. This is to compare the change in the detected value of the hot wire anemometer for only the width.

In the embodiment shown in FIG. 1, the SS concentration meter 14 is used, and the SS concentration of the filtrate is used as a chemical injection saturation indicator factor. In the present invention, in addition to this, the water content of the dehydrated cake and the filtration time of the dehydrated filtrate may be used as the chemical injection saturation indicator.

FIG. 3 is a graph showing the relationship between the chemical injection amount, the hot wire anemometer detection value and the water content of the dehydrated cake. As shown in the figure, the water content of the dehydrated cake monotonously decreases with an increase in the dosage amount up to the dosage amount N, but when it exceeds N, the water content does not decrease any more and becomes saturated. Therefore, by referring to the water content of the dehydrated cake, it is possible to easily bring the dosage amount close to the optimum addition amount N.

To measure the water content of the dehydrated cake, a weight type sensor for detecting a change in cake weight due to heating, a sensor for irradiating the cake with infrared rays or near infrared rays to obtain water content, and the like are exemplified.

FIG. 4 is a graph showing the relationship between the amount of chemical injection, the detection value of the hot wire anemometer and the filtration time of the dehydrated filtrate. As shown in the figure, this filtration time monotonously decreases with the increase of the dosage amount up to the dosage amount N, but when it exceeds N, it does not decrease any further and becomes saturated. Therefore, by referring to this filtration time, the chemical injection amount can be easily brought close to the optimum addition amount N.

In order to measure the filtration time of the dehydrated filtrate, the time required to pass a fixed amount of filtrate through the filtration membrane, perforated plate, slit plate, etc. may be measured. In the above embodiment, the coagulation tank is dosed, but in the present invention, a coagulation apparatus of the type in which the liquid to be coagulated is circulated (for example, a raw water supply pipe) is also used. Applicable.

In the above embodiment, the filtrate is continuously flown into the filtrate storage tank, but in the present invention, a predetermined amount of filtrate may be received in the filtrate storage tank to measure the detection value of the hot wire anemometer and the like.
When performing batch measurement in this way, for example, a level meter is provided in the filtrate storage tank, after discharging the entire amount of the filtrate at the time of the previous measurement, the level meter receives the filtrate until the detected water level reaches a predetermined level, and heat It suffices to measure the anemometer detection value and the like.

In the present invention, the control may be carried out so that the drug injection amount becomes a minimum, or the drug injection amount may be controlled within the target range.

[0042]

As described above, according to the agglomeration processing apparatus of the present invention, by using the heat transfer detector and the saturation indicator of the chemical injection, the accurate chemical injection amount can be obtained so that the chemical injection amount becomes the optimum amount. It becomes possible to control. Therefore, excess or deficiency of the chemical injection amount is prevented, and efficient and low cost aggregation processing can be performed.

[Brief description of drawings]

FIG. 1 is a system diagram of an apparatus according to an embodiment.

FIG. 2 is a graph showing a relationship between a sensor detection value and a drug injection amount.

FIG. 3 is a graph showing a relationship between a sensor detection value and a drug injection amount.

FIG. 4 is a graph showing a relationship between a sensor detection value and a drug injection amount.

FIG. 5 is a graph showing experimental results.

FIG. 6 is a graph showing experimental results.

FIG. 7 is a graph illustrating a control method.

FIG. 8 is a block diagram of a hot wire anemometer.

[Explanation of symbols]

 4 Coagulation tank 8 Chemical injection pump 9 Dehydrator 12 Hot wire anemometer 16 Arithmetic controller

Claims (1)

[Claims] 1. A chemical injection device for adding a coagulant to a liquid to be coagulated, a heat transfer detector provided in contact with the dehydrated filtrate, and a detection value of the heat transfer detector. A control device for controlling the chemical injection amount of the chemical injection device, and in an agglomeration processing device comprising, a sensor for detecting the chemical injection saturation indicator factor of the dehydrated filtrate or dehydrated cake is provided, and the control device is An aggregating treatment device, wherein the chemical injection amount is controlled based on the detection values of the heat transfer detector and the sensor.