JPH03174205A - Slurry blanket-type flocculating and settling device - Google Patents

Abstract

PURPOSE:To appropriately keep the suspensoid content by calculating the total suspensoid content from the detection signal of a turbidimeter to obtain an increment of suspensoid and further providing an arithmetic controller for commanding the sludge discharging time. CONSTITUTION:The detection signal of the turbidimeter 11 is inputted to the arithmetic controller 12. The appropriate suspensoid content in the tank 1 corresponding to the previously known raw water turbidity pattern, raw water flow rate pattern and flocculant injection pattern is stored in the controller 12, and the total suspensoid content in the tank 1 is calculated from the detection signal of the turbidimeter 11. Furthermore, the opening time of a sludge valve 13 is commanded from the increment of suspensoid and the bottom turbidity detection signal of the turbidimeter 11 to discharge the increment. The circulating amt. is determined by the turning rate of the impeller 9, and the position of the slurry interface 10 in the tank 1 is controlled. Water is stably treated in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is aimed at constantly maintaining an appropriate amount of turbidity and stabilizing it in a slurry blanket type coagulation sedimentation device used for treating clean water, industrial water, various wastewater, etc. The present invention relates to a device that can perform such processing.

[Conventional technology]

In the slurry blanket type coagulation sedimentation device, uncoagulated flocs are mixed with the existing 4! In order to be brought into contact with the collected flocs and to grow sufficiently, it is necessary to maintain an appropriate amount of suspended solids in the device.

The amount of turbidity retained in the equipment varies depending on the amount of turbidity supplied from raw water and the amount of sludge removed. This results in deterioration of the turbidity of the treated water. In addition, insufficient sludge removal causes an increase in the amount of suspended solids retained, leading to a rise in the slurry interface position and floc carryover.

Conventionally, the turbidity distribution inside the equipment was determined by raw water turbidity, raw water flow rate,
Since it varies depending on the type of flocculant used and the amount of injection, etc.,
Estimates were made by measuring points or several points, and sludge was removed empirically while referring to past similar data to maintain an appropriate amount of suspended solids.

[Invention tries to solve it! ! 1! By the way, if the raw water conditions such as raw water turbidity and raw water flow rate do not change much, there is no need to change the sludge removal conditions that much. Measure the slurry interface position, slurry turbidity, etc., and monitor the internal conditions of the equipment.

It is necessary to change the sludge removal conditions, and the judgment and operation required to do so are extremely complicated, and there has been a need for simple and effective automatic control.

The present invention uses a detected value of turbidity at the bottom of the device to calculate the increase or A slurry blanket type that automatically controls the amount of sludge removed, always maintains an appropriate amount of suspended solids, enables stable treatment, improves the reliability of the equipment, and saves management labor. The object of the present invention is to provide a coagulation sedimentation device.

[Means to solve the problem]

As a means for solving the above problem, in claim 1 of the present invention, a turbidity meter that can continuously detect the turbidity distribution in the water depth direction is provided, and a raw water turbidity pattern and raw water flow rate that are known in advance are provided. pattern.

The appropriate turbidity retention amount corresponding to the flocculant injection amount pattern is memorized, the total turbidity retention amount is calculated based on the detection signal of the turbidimeter, the turbidity increase is calculated, and the turbidity increase and the turbidity increase are calculated. Claim 2 further provides a slurry blanket type coagulation sedimentation apparatus, characterized in that it is equipped with an arithmetic and control device that commands the sludge drainage time based on the bottom turbidity detection signal of the turbidity meter.
In addition to providing each detection meter that detects the flow rate of raw water and the amount of coagulant injected, and the turbidity meter that detects the turbidity at the bottom, the raw water turbidity pattern and raw water flow rate pattern are known in advance.

The appropriate turbidity retention amount corresponding to the flocculant injection amount pattern is memorized, and the inflow turbidity amount is calculated based on each detection signal of the inflowing raw water turbidity, raw water flow rate, and flocculant injection amount, and the turbidity increase is calculated. The present invention provides a slurry blanket type coagulation-sedimentation apparatus, characterized in that it is equipped with an arithmetic and control device that commands a sludge drainage time based on the turbidity increase and the turbidity detection signal of the turbidity meter.

[For production]

First, in the present invention of claim 1, various raw water turbidities, raw water flow rates, and flocculant injection amounts that can be considered under operational conditions are patterned in advance, and the appropriate turbidity retention amount corresponding to these patterns is analyzed, calculated, and It is set through processing tests, etc., and stored in the arithmetic and control unit.

When the operation is started, the turbidity distribution in the water depth direction is continuously detected by the turbidity meter, and these detection signals are input to the arithmetic and control unit, and the amount of turbidity retained at that time is calculated.

That is, since each turbidity in the water depth direction is known and the cross-sectional area at each water depth is determined, the total ifi quality content can be calculated by integrating. Therefore, the arithmetic and control unit calculates the amount of turbidity that has increased from the stored appropriate turbidity retention amount at that time, instructs the drainage time to drain the increased amount, and always maintains the appropriate 1g1i quality. Automatically controls sludge removal to maintain the same amount.

Further, in the present invention according to claim 2, it is the same as the above-described invention according to claim 1 that the arithmetic and control device stores appropriate turbidity retention amounts corresponding to various patterns considered in advance.

When the operation is started, the turbidity of the inflowing raw water, the flow rate of the raw water, and the amount of coagulant injected are detected, the detection signals are input to the arithmetic control N device, and the amount of inflowing turbidity is calculated from these input signals. Therefore, the arithmetic and control device calculates the amount increased from the appropriate amount of turbidity from this inflow W4 mass and the stored appropriate amount of turbidity, and instructs the sludge removal time to remove the increased amount. Then, sludge removal is automatically controlled to maintain an appropriate amount of rA at all times.

By the way, in each of the above inventions, since sludge is drained from the bottom of the device, the turbidity of the drained sludge has a correlation with the turbidity at the bottom of the device. Bottom turbidity detected by turbidity meter1. and the sludge turbidity t2 is t, = to -t.

There is a relationship such that k is determined in advance by measuring the turbidity of t and t at several points. In addition, the amount of turbidity discharged (
Sludge volume) Q is: Q - Outflow volume vx L.

Determined by the sludge removal time.

Therefore, when draining the increased amount of turbidity, the bottom turbidity t
, is detected, t is determined by the arithmetic and control device, and the mud can be discharged by commanding the mud discharge time.

Further, the command of the sludge removal time by the arithmetic and control device can be performed in the following manner.

■ Keep the sludge draining time constant. Make the sludge valve open time constant. In other words, the amount of sludge removed per time is fixed, and the amount of sludge removed is determined by the sludge removal interval.

That is, the sludge is drained when the amount of increased turbidity reaches the amount of sludge that is required to be drained once.

■ Keep the sludge drainage interval constant Set the sludge drainage interval so that a predetermined amount of increased turbidity accumulates.

In this way, the sludge is automatically controlled to maintain an appropriate amount of turbidity in the device and stable processing is performed, but if there is a discrepancy between the calculated value and the actual flow rate, etc. During long-term operation, the amount of suspended matter in the equipment increases and decreases. In that case, the following corrections will be made.

For example, if the amount of turbidity retained exceeds the maximum allowable value of the appropriate amount of retained turbidity, sludge is drained for a certain period of time, and if the maximum allowable amount is still exceeded after a certain period of time, sludge is drained again.
Thereafter, this process is repeated and normal control is performed when the value falls within the allowable value. Furthermore, if the retained amount of suspended solids falls below the minimum allowable value of the appropriate retained amount of suspended solids, sludge removal is stopped until the amount returns to within the allowable value.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the invention of claim 1, in which 1 is a tank body of a slurry plunket type coagulation sedimentation Wj device, a raw water inflow pipe 2 is connected to the bottom and a frontage is connected to the top, and the treated water flows out from the top. A long tube 3 is provided and is connected to a treated water outflow section 4. 5 is a treated water outflow pipe.

A draft tube 6 that guides the raw water flowing in from the raw water inflow pipe 2 is provided in the center of the tank body 1 so as to be able to rotate gently, and a distribution tube 6 that rotates together with the draft tube 6 and distributes the raw water is provided at the bottom of the draft tube 6. Tough is connected and fixed.

In addition, an impeller 9 driven by a motor 8 is provided inside the draft tube 6, and the rotation of this impeller 9 mixes the flocculant injected into the raw water.
The inside of the slurry is lowered and distributed to the inner bottom of the tank body 1 through the distribution tuff, and a part of the slurry distributed from the distribution tuff is mixed into the inflowing raw water and circulated.

The amount of circulation is determined by the rotation speed of the impeller 9, and defines the position of the slurry interface 10 within the tank body 1.

Reference numeral 11 denotes a turbidity meter that can move up and down to continuously detect the turbidity in the depth direction of the water inside the tank body 1, and usually uses a phototube method or an ultrasonic method, and its detection signal is sent to the arithmetic and control unit 12. is input. The arithmetic and control device 12 stores the appropriate amount of turbidity in the tank body 1 corresponding to various raw water turbidity patterns, raw water flow rate patterns, and flocculant injection amount patterns known in advance, and also stores the appropriate amount of turbidity in the tank body 1. A function that calculates the total amount of turbidity held in the tank body 1 based on the detection signal, calculates the increased amount of turbidity that has increased from the memorized appropriate amount of turbidity held, and combines this increased amount of turbidity with the turbidity meter 11. It has a function of commanding the opening time of the sludge valve 13 in order to sludge the increased amount of turbidity based on the bottom turbidity detection signal.

FIG. 2 shows the invention according to claim 2, and the basic structure is the same as that in FIG. 1, and the different points will be explained below.

The raw water inflow pipe 2 is provided with a raw water turbidity meter 14 for detecting the turbidity of incoming raw water, a raw water flow meter 15 for detecting the flow rate of raw water, and an injection pump 16 having a flocculant injection amount detection function. The detection signal and the bottom turbidity detection signal of the turbidity meter 11 are input to the arithmetic and control unit j17. The arithmetic and control device 17, like the arithmetic and control device shown in FIG. A function that calculates the amount of inflow turbidity and an increase in turbidity from the stored appropriate amount of turbidity, and from this increase in turbidity and the bottom turbidity detection signal of the turbidity meter 11, the turbidity is calculated. It has a function of commanding the opening time of the sludge valve 13 in order to remove the increased amount of sludge.

〔Effect of the invention〕

As described above, the slurry blanket type coagulation sedimentation device of the present invention is controlled to automatically drain the increased amount of turbidity so that an appropriate amount of turbidity is always maintained in the device, Enables stable processing and improves equipment reliability.
This allows for labor-saving management.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory diagrams each showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Tank body, 2... Raw water inflow pipe, 3... Outflow long, 4... Treated water outflow 1 part, 6... Draft tube, 7... Distributor, 8... Motor , 9
... Impeller, 10... Slurry interface, 11... Turbidity meter, 12.17... Arithmetic control unit, 13... Sludge valve, 14... Raw water turbidity meter, 15...・Raw water flow meter, 1
6... Infusion pump.

Claims (2)

[Claims] (1) In addition to installing a turbidity meter that can continuously detect the turbidity distribution in the water depth direction, the appropriate turbidity retention amount corresponds to the pre-known raw water turbidity pattern, raw water flow rate pattern, and flocculant injection amount pattern. , calculate the total turbidity retention amount based on the detection signal of the turbidity meter, calculate the turbidity increase, and further calculate the amount of turbidity removed from the turbidity increase and the bottom turbidity detection signal of the turbiditymeter. A slurry blanket type coagulation sedimentation device characterized by being equipped with a calculation control device that commands mud time. (2) In addition to installing detection meters that detect raw water turbidity, raw water flow rate, and amount of flocculant injected, and a turbidity meter that detects the turbidity at the bottom, the raw water turbidity pattern, raw water flow rate pattern, and flocculation that are known in advance are installed. The appropriate turbidity retention amount corresponding to the agent injection amount pattern is memorized, and the inflow turbidity amount is calculated based on each detection signal of the inflowing raw water turbidity, raw water flow rate, and flocculant injection amount, and the turbidity increase is calculated. A slurry blanket type coagulation sedimentation apparatus, characterized in that it is equipped with an arithmetic and control device that commands sludge drainage time based on the increased amount of turbidity and the turbidity detection signal of the turbidity meter.