JPH0871600A - Sludge treatment apparatus - Google Patents

Abstract

PURPOSE: To well control the solid-liquid separation of raw sludge corresponding to a change in the properties of sludge by the optimum injection of an inorg. flocculant and an amphoteric polymer. CONSTITUTION: A pH meter 13 measuring the pH value of the separated liquid discharged from a centrifugal dehydrator 4 and a colorimeter 14 measuring the color of the bubble of the separated liquid discharged from the centrifugal dehydrator 4 are provided. The supply amts. of the inorg. flocculant and amphoteric polymer to be mixed with raw sludge is optimally controlled according to the respective measured results of the colorimeter 14 and the pH meter 13 by a separated liquid monitor and control means 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge treatment device for treating sludge by centrifugal dehydration.

[0002]

2. Description of the Related Art Conventionally, various techniques for sludge treatment by solid-liquid separation treatment employing a centrifugal dehydration method have been provided. In order to accelerate the solid-liquid separation treatment, for example, an inorganic coagulant and an amphoteric polymer are used. Used by being mixed with raw sludge.

The inflow amount (mixed amount) of these inorganic coagulants and amphoteric polymers into the raw sludge needs to be monitored and controlled so as to be a certain value. PH is measured in the sludge supply line to the inside of the tank or the centrifugal dehydrator, and the inflow amount of the inorganic coagulant is arbitrarily adjusted according to the measurement result.

As the above-mentioned inorganic coagulant, for example, P
Aluminum oxide (PAC) with H of 4.5 to 5.0 (1500
It is known that a good solid-liquid separation state can be obtained by using (about 2000 ppm).

On the other hand, the amphoteric polymer is empirically determined by arbitrarily determining the inflow amount into the raw sludge and measuring the TS concentration of the raw sludge to perform proportional injection corresponding to this concentration.

With respect to the amphoteric polymer, when the inflow concentration proportional control of 0.7% with respect to the concentration TS of the original sludge is performed and the separation state is not good due to changes in the sludge properties, the separation liquid is The bubbles that appear turn black.

[0007]

However, in the conventional sludge treatment method as described above, the pH of the raw sludge is directly measured by the PH meter immersed in the raw sludge in the sludge tank. However, there is a problem that the PH sensor is easily soiled and the PH measurement cannot be performed correctly.

Further, regarding the above-mentioned amphoteric polymer, it is unavoidable that the concentration of the raw sludge is not uniform and the concentration sensor is soiled by the direct measurement of the concentration of the raw sludge, and the measurement error caused by the contamination is caused. Since the injection amount (inflow amount) with respect to is dependent on human intuition, there is a problem that the optimum amount cannot be injected, resulting in non-uniform sludge separation results.

Further, there is a problem that even if the injection rate of the amphoteric polymer is controlled to be constant, it is not possible to cope with fluctuations in sludge properties.

The present invention has been made in order to solve the above-mentioned conventional problems, and in accordance with changes in sludge properties, solid-liquid separation of raw sludge is performed by optimal injection of inorganic coagulant and amphoteric polymer. An object of the present invention is to obtain a sludge treatment device that can be well controlled by.

[0011]

A sludge treatment device according to the present invention is a centrifugal sludge in which an inorganic coagulant and an amphoteric polymer are mixed with raw sludge and solid-liquid separation is performed by centrifugal dehydration to produce a separated liquid and a dehydrated cake. A dehydrator, a PH meter for measuring the PH value of the separated liquid discharged from the centrifugal dehydrator, and a colorimeter for measuring the color of bubbles of the separated liquid discharged from the centrifugal dehydrator are provided. According to the measurement results by the chromaticity meter and the PH meter, the separated liquid monitoring control means is made to optimally control the supply amounts of the inorganic coagulant and the amphoteric polymer to be mixed in the raw sludge.

[0012]

In the sludge treatment device according to the present invention, the color of the foam of the separated liquid discharged from the centrifugal dehydrator is monitored by a colorimeter, and when the color of the foam is black, the separated liquid is deteriorated. Judgment is made so that the amount of the amphoteric polymer mixed is increased so that the color of the foam becomes white, while the pH of the separated liquid is monitored,
The mixing amount of the inorganic coagulant is controlled so that the PH value falls within about 5.

This makes it possible to efficiently perform centrifugal dehydration of the raw sludge, and to prevent contamination of the sensor itself of the colorimeter or PH meter and the occurrence of measurement errors due to the contamination.

[0014]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a sludge tank in which raw sludge is stored, and 2 is a pipe 3 for feeding the raw sludge in the sludge tank 1.
It is a pump that delivers to the outside through the.

Reference numeral 4 denotes a centrifugal dehydrator for accommodating the raw sludge sent out by the pump 2 and separating and extracting the separated liquid and the dehydrated cake of the raw sludge which has been dehydrated by centrifugation at a high speed.

Further, 5 is an inorganic coagulant tank containing an inorganic coagulant, 6 is a pump for sending the inorganic coagulant from the inorganic coagulant tank 5 to the pipe 3 and mixing it with the raw sludge, and 7 is the inorganic coagulant. It is a controller that controls the delivery amount of the coagulant 5.

Further, 8 is an amphoteric polymer tank containing an amphoteric polymer, 9 is a pump for sending the amphoteric polymer from the amphoteric polymer tank 8 to the pipe 3 and mixing it with the raw sludge, 10 is a sending amount of the amphoteric polymer Is a controller for controlling the.

Reference numeral 11 denotes a pipe for discharging the separated liquid discharged from the centrifugal dehydrator 4, and a bypass pipe 12 for bypassing a part of the separated liquid is connected to the pipe 11, and on the way of the bypass pipe 12. Further, a separated liquid monitoring control device 15 provided with a PH meter 13 and a chromaticity meter 14 and a pump 16 are connected. Reference numeral 17 is a drainage passage for the dehydrated cake.

The pH meter 13 measures the pH of the separated liquid.
The value is measured, and the colorimeter 14 measures the color of bubbles generated in the separated liquid, and each measured value data can be supplied from the separated liquid monitoring controller 15 to the controllers 7, 10. .

Next, the operation will be described. First, the pump 2 is driven to feed the raw sludge stored in the sludge tank 1 into the centrifugal dehydrator 4 rotating at high speed through the pipe 3.

At this time, the inorganic coagulant tank 5 is also used.
The inorganic coagulant in the pipe 3 is fed into the pipe 3 by the pump 6, and is mixed with the raw sludge in the pipe 3, and the amphoteric polymer in the amphoteric polymer tank 8 is fed into the pipe 3 by the pump 9, which is supplied to the pipe 3 Mixed with the original sludge inside.

Therefore, in the centrifugal dehydrator 4, the liquid material in which the raw sludge is mixed with the inorganic coagulant and the amphoteric polymer is separated into the solid material and the liquid material by the centrifugal separation action by the high speed rotation. The dehydrated cake as is appropriately discharged from the centrifugal dehydrator 4 through the discharge passage 17 and subjected to disposal or the like, and the separated liquid as a liquid is also subjected to necessary water purification processing or the like and discarded or recovered.

At this time, part of the separated liquid is pump 16
Is supplied to the separated liquid monitoring and control device 15 via the bypass pipe 12, and by the PH meter 13 attached thereto,
The pH value of the separated liquid is measured and the colorimeter 14
Therefore, the chromaticity of the bubbles of the separated liquid passing through the bypass pipe 12 is measured.

In these measurements, since the sensors of the PH meters 13 and the chromaticity meter 14 themselves are not exposed to the raw sludge, the PH value and the chromaticity of bubbles can be detected with high accuracy.

In this case, in the two-component method centrifugal dehydration using the amphoteric polymer and the inorganic coagulant, the use of aluminum oxide having a pH of 5.0 (2000 ppm) improves the state of the separated liquid, while the separated liquid on the separated liquid The chromaticity meter value BC (BC100 → white, BC0 → black) of the foam generated in 50 to 60
By adjusting the degree, the state of the separated liquid becomes good as in the above.

Therefore, in the present invention, the separated liquid monitoring controller 15 operates the controller 6 so that the PH value measured by the PH meter 13 becomes 5.0, and the inorganic coagulant tank by the pump 6 is operated. Optimum control of the delivery amount of the inorganic coagulant from 5.

On the other hand, regarding the amphoteric polymer, the colorimeter 1
When the colorimeter value BC measured by 4 is 60 or more, it is determined that the amount of the amphoteric polymer mixed so far is excessive, and the separated liquid monitoring control device 15 operates the controller 10,
The amount of amphoteric polymer delivered from the amphoteric polymer tank 8 by the pump 9 is reduced.

When the chromaticity meter value BC is 50 to 60, it is determined that the mixing amount of the amphoteric polymer is within the proper range, and the pumping amount of the amphoteric polymer is maintained as it is. On the contrary, when the colorimeter value BC is 50 or less, it is determined that the amount of the amphoteric polymer mixed in is insufficient because the bubbles are turbid, and the amount of the amphoteric polymer delivered by the pump 9 is determined. increase.

In this way, in response to changes in sludge properties, that is, the state of the separated liquid after separation of the dehydrated cake (BC
In addition to the optimal control of the state of this separated liquid according to the value), it is possible to avoid contamination of the PH meter sensor itself, and the original sludge treatment condition can be maintained in a good condition, and the treatment efficiency is significantly higher than before. Can be improved.

[0030]

Industrial Applicability As described above, according to the present invention, a centrifugal dehydrator that mixes an inorganic coagulant and an amphoteric polymer with raw sludge and performs solid-liquid separation by centrifugal dehydration to produce a separated liquid and a dehydrated cake. And a pH meter for measuring the PH value of the separated liquid discharged from the centrifugal dehydrator, and a colorimeter for measuring the color of bubbles of the separated liquid discharged from the centrifugal dehydrator, According to each measurement result by the colorimeter and the PH meter, the separated liquid monitoring control means is configured to optimally control the supply amount of the inorganic coagulant and the amphoteric polymer to be mixed in the raw sludge, so that the sludge property changes. According to the above, solid-liquid separation of raw sludge can be well controlled by optimal injection of inorganic coagulant and amphoteric polymer, and contamination of PH sensor etc. can be prevented to optimize injection amount of inorganic coagulant. Can control There is an effect that things can be obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a sludge treatment device according to an embodiment of the present invention.

[Explanation of symbols]

 4 Centrifugal dehydrator 13 PH meter 14 Chromaticity meter 15 Separation liquid monitoring control device (separation liquid monitoring control means)

Claims (1)

[Claims] 1. A centrifugal dehydrator that mixes an inorganic coagulant and an amphoteric polymer with raw sludge and performs solid-liquid separation by centrifugal dehydration to produce a separated liquid and a dehydrated cake, and the above-mentioned centrifugal dehydrator discharged from the centrifugal dehydrator. According to each measurement result by the PH meter for measuring the PH value of the separated liquid, the color meter for measuring the color of bubbles of the separated liquid discharged from the centrifugal dehydrator, according to each measurement result by the color meter and the PH meter, A sludge treatment device provided with a separation liquid monitoring control means for optimally controlling the supply amounts of an inorganic coagulant and an amphoteric polymer to be mixed in raw sludge.