JPS63278510A - Method for controlling agitation of flocculation basin - Google Patents

Abstract

PURPOSE:To exclude visual observation and to accurately control the agitation of a flocculation basin by injecting a flocculant into a sampled suspension, obtaining an appropriate injection rate in accordance with the flocculating condition obtained from the quantity of transmitted light, and controlling the agitation of the flocculation basin from the flocculating time obtained from the quantity of transmitted light and an agitating velocity gradient. CONSTITUTION:The determination of the amt. of a flocculant to be injected into a suspension being rapidly agitated in a mixing basin 106 and the control of the slow and rapid agitation in the flocculation basin 112 are carried out by the following method. Namely, a flocculant is injected into the suspension sampled on the upstream side of the mixing basin 106, the suspension is agitated in the agitated vessel at a low velocity, the quantity of the light received from a light emitting device through the suspension is measured to detect the flocculating condition and flocculating time, and the velocity gradient of agitation is obtained. The appropriate injection rate of the flocculant is determined from the flocculating condition, and the agitation is controlled based on the flocculating time, velocity gradient, amt. of the suspension flowing into the mixing basin 106, and volume of the flocculation basin 112. By this method, visual observation and experience can be excluded, and the agitating time can be reduced and optimized.

Description

Detailed Description of the Invention (1) Purpose of the Invention [Field of Industrial Application] The present invention relates to a method for controlling agitation in a flocculate formation pond, and in particular, the present invention relates to a method for controlling agitation in a flocculation pond, and in particular, a method for injecting a flocculant into a collected suspension while stirring it. Determine the appropriate injection rate of the flocculant, preferably determine the appropriate velocity gradient and aggregate formation time corresponding to this appropriate injection rate, and calculate the amount of suspension supplied to the mixing pond. This invention relates to an agitation control method for an agglomerate formation pond, which comprises controlling the amount of mw agent injected into a mixing pond by detecting the volume of the agglomeration pond, and controlling agitation in the agglomeration formation pond. .

[Prior Art] Conventionally, as a stirring control method for this type of flocculation pond, a flocculant is added each time a suitable amount of a suspension of tap water, industrial water, sewage, industrial waste liquid, etc. is collected. After injecting at varying injection rates, stirring and standing still, the tester detects the flocculating state through visual observation and experience, determines the appropriate injection rate of the flocculant, and then rapidly stirs in the mixing basin according to this appropriate injection rate. A flocculant was injected into the suspension, and the flocculant was then stirred at a slow speed in a flocculate formation pond. It has been proposed to judge the state of aggregate formation and adjust the agitation control in the aggregate formation pond based on the result.

[Problems to be Solved] However, in the conventional agitation control method for agglomerate formation and foam formation, the appropriate injection rate of the agglomerate or the agitation process in the agglomerate formation pond was determined by the tester's visual observation and experience. There is a drawback that the judgment results differ depending on the tester, and it is not possible to adequately optimize the stirring process in the aggregate formation pond.Also, since it takes more than 30 minutes to form aggregates in the aggregate formation pond, it is difficult to determine the state of the aggregate formation. It takes a lot of time to judge the suspension, and it is difficult to respond quickly to changes in the suspension.At the same time, stirring control in the aggregate formation pond cannot be executed with high precision, especially when the aggregate formation basin is spread over multiple areas. In the case of dividing, there is also a drawback that once formed aggregates are destroyed by stirring in subsequent regions.

In order to eliminate these drawbacks, the present invention aims to inject a flocculant into a stirring region between a light emitting device and a light receiving device while rapidly stirring the sampled suspension, and then slowly stirring the suspension. The appropriate injection rate of the flocculant is determined by detecting the flocculating state of the suspension in which the flocculant has been injected from the amount of light received by the light receiving device during stirring and after the stirring has stopped, and then the speed corresponding to the appropriate injection rate is determined. Gradient and Agglomerate Formation Time Preferably, an appropriate velocity gradient and an appropriate aggregate formation time are determined, and a flocculant is injected into the mixing basin accordingly, and the agitation of the aggregate formation basin is controlled. The present invention aims to provide a stirring control method.

(2) Structure of the Invention [Means for Solving Problems] The first means for solving problems provided by the present invention is as follows: ``After injecting a flocculant into a suspension while rapidly stirring it in a mixing basin, In an agitation control method for an aggregate formation pond, which forms aggregates by slow stirring in the aggregate formation pond.

(a) a first step of injecting a flocculant into the suspension collected in the first flow from the mixing pond and stirring it in a stirring tank; a second step of stirring the suspension into which the flocculant was injected in the first step at a stirring speed;

(c) at least in the second step, a third step of measuring the amount of light received from the light emitting device to the light receiving device via the suspension into which the flocculant was injected in the first step; a fourth step of detecting the aggregation state of the suspension into which the flocculant was injected in the first step from the amount of light received measured in the third step; (e) the aggregation state detected in the fourth step; (f) determining the appropriate injection rate of the flocculant in accordance with the rate of injection of the flocculant in the first step; and a sixth step of determining the aggregate formation time of the suspension.

(g) a seventh step of detecting the amount of suspension supplied to the mixing pond;

(h) Using the velocity gradient and aggregate formation time determined in the sixth step, the supply amount of the suspension detected in the seventh step, and the volume of the aggregate formation pond, (1) The injection amount of the flocculant is determined from the suspension supply amount detected in the tjS7 step and the appropriate injection rate of the flocculant determined in the fifth step. (j) a tenth step of injecting a flocculant into the mixing pond according to the injection amount calculated in the ninth step. ``Method for controlling agitation in a formation pond.''

Other solutions to the problems provided by the present invention are as follows.

"In an agitation control method for an aggregate formation pond, in which a flocculant is injected into a suspension with rapid stirring in a mixing basin, and then aggregates are formed by slow stirring in an aggregate formation basin. a) A first step of injecting a flocculant into the suspension collected upstream of the mixing pond and stirring it in a stirring tank.

(b) a second step of stirring the suspension into which the flocculant has been injected in the first step at a stirring speed lower than that of the first step; (d) measuring the amount of received light given to the light receiving device from the light emitting device via the suspension into which the flocculant has been injected; (e) determining the appropriate injection rate of the flocculant according to the flocculation state detected in the fourth step; The fifth step.

(“) a sixth step of determining a velocity gradient corresponding to the appropriate injection rate determined in the fifth step;

(g) a seventh step of determining, from among the velocity gradients determined in the sixth step, a velocity gradient that makes the agglomeration state detected in the fourth step appropriate as an appropriate velocity gradient; An eighth step in which the aggregate formation time of the suspension in which the flocculant was injected in the first step is determined in accordance with the appropriate velocity gradient determined in step 7, and the aggregate formation time is set as the appropriate aggregate formation time; 1) a ninth step of detecting the amount of suspension supplied to the mixing pond; and U) detecting the appropriate velocity gradient determined in the seventh step, the appropriate aggregate formation time determined in the eighth step, and a tenth step of controlling the agitation in the pre-arranged aggregate formation pond using the supply amount of the suspension detected in step 9 and the volume of the aggregate formation pond;

(k) an eleventh step of calculating the injection amount of the flocculant from the supply amount of the suspension detected in the ninth step and the appropriate injection rate of the flocculant determined in the fifth step;

(1) A twelfth step of injecting a flocculant into the mixing pond according to the injection amount calculated in the eleventh step. be.

[Function] The first stirring control method for the aggregate formation pond according to the present invention is as follows:
In an agitation control method for an aggregate formation pond, in which a flocculant is injected into a suspension with rapid stirring in a mixing basin, and then aggregates are formed by slow stirring in an aggregate formation pond. After injecting a flocculant into the suspension, the stirring speed is reduced, and the amount of received light given from the light emitting device to the light receiving device is measured through the suspension into which the flocculant has been injected. Detecting the agglomeration state of the suspension from the amount of light, determining the appropriate injection rate of the flocculant according to the detected aggregation state, and determining the velocity gradient and aggregate formation time corresponding to the determined appropriate injection rate. , detecting the amount of suspension supplied to the mixing pond, injecting the flocculant into the suspension in the mixing basin according to the appropriate injection rate of the flocculant, and adjusting the velocity gradient and the aggregate formation time. It functions to execute stirring control of the aggregate formation pond according to the supply amount of the suspension and the volume of the aggregate formation pond, and the tester's visual observation tjR? v
In addition, it has the effect of eliminating experience, and also has the effect of optimizing the agitation control of the agglomerate formation pond in a short time while avoiding actually measuring the result of the agitation process in the aggregation formation pond.

In addition, the second agitation control method of the flocculate formation pond according to the present invention is that after injecting the flocculant into the suspension while stirring rapidly in the mixing basin, the flocculant is injected into the suspension and then slowly stirred in the flocculation basin. In a stirring control method for an aggregate formation pond formed by forming aggregates, a flocculant is injected into the collected suspension, and then the stirring speed of the suspension is reduced, and the suspension into which the flocculant has been injected is The amount of received light given from the light emitting device to the light receiving device via the light emitting device is measured, the agglomeration state of the suspension is detected from the amount of received light, and the appropriate injection rate of the flocculant is determined according to the detected aggregation state. Then, a velocity gradient is determined corresponding to the determined appropriate injection rate, and among the velocity gradients, a velocity gradient that makes the detected aggregation state appropriate is determined as an appropriate velocity gradient, and a velocity gradient corresponding to the appropriate velocity gradient is determined. The aggregate formation time is determined as the appropriate aggregate formation time, the amount of suspension supplied to the mixing pond is detected, and the flocculant is added to the suspension in the mixing basin according to the appropriate injection rate of the flocculant. is injected, and performs stirring control of the aggregate formation pond according to the appropriate velocity gradient, appropriate aggregate formation time, the supply amount of the suspension, and the volume of the aggregate formation pond. In addition to the effect of eliminating the visual observation and experience of the tester and the effect of optimizing the agitation control of the agglomerate formation pond in a short time while avoiding the actual measurement of the results of the agitation process in the agglomeration formation pond, It not only detects an appropriate injection rate but also determines an appropriate velocity gradient and an appropriate aggregate formation time, thereby shortening the time required for stirring control of an aggregate formation pond.

[Example] Next, the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an actual suspension processing apparatus in which agitation control of an agglomerate formation pond is executed by an embodiment of the agitation control method for an agglomerate formation pond according to the present invention.

FIG. 2 shows the detection of the appropriate injection rate WAI of the flocculant into the suspension, the appropriate aggregate formation time Tt at that time, and the appropriate velocity gradient G♂ in order to carry out an embodiment of the present invention. 2 is a sectional view specifically showing an example of the detection device of FIG. 1. FIG.

FIG. 3 is an explanatory diagram for explaining the operation of the detection device shown in FIG. 2, and shows temporal changes in the amount of received light I. FIG.

Figure 4 shows the diameter d of the aggregate obtained from the operation diagram in Figure 3.
, a number Nb9 volume vj5 and an effective density ρ, and a graph showing the relationship between the flocculant injection rate WAl.

Figure 5 shows the supernatant water turbidity τ obtained from the operation diagram in Figure 3.
, is a graph diagram showing the relationship between the sedimentation rate S and effective density ρ of the flocculant and the injection rate WAI of the flocculant.

FIG. 6 is a sectional view showing a detection device in which four detection devices of FIG. 2 are arranged side by side.

First, with reference to FIG. 1, an actual suspension processing apparatus in which agitation control of an agglomerate formation pond is executed by the agitation control method for an agglomerate formation pond according to the present invention will be described.

Reference numeral 102 denotes a landing well, into which a suspension is supplied via a supply pipe 104 from an appropriate suspension supply source (not shown). 10
Reference numeral 6 denotes a mixing pond for a suspension and a flocculant, which is communicated with the landing well 102 via a supply pipe 108, and is provided with a stirring blade 110 that is rapidly rotated by a driving means, such as an electric motor 109.

Reference numeral 112 denotes an aggregate formation pond which is communicated with the mixing basin 106 via a supply pipe 114, and has a desired number of regions, for example, three regions 112A, 112A, 112A, 112A, 112A, 112B, 112A, 112B, 112A, 112B, 112A, 112A, 112B, 112B, 112A, 112A, 112B, 112A, 112A, 112B, 112A, 2B, 3B, 3A, 3B, 3A, 2B, 3A, 2B, 3A, 2B, 3A, 3B, 3A, 3B, 3A, 3B, and 32B.
, 112C, respectively stirring 4i111
3A, ~, ll IC installed saletail, Wl stirrer 11
ko^, ~, 11:l (: represents the rotational speed n by the driving means, for example, electric motors 115A, ~, 115G, and the driving means, such as electric motors 115A, ~, 115G, respectively.
^, stirring blade 116 ^ rotated slowly at ~enc.

~, 116G. The flocculant is injected and mixed in the mixing pond 106 and sent to the flocculation pond 1 through the supply pipe 114.
The suspension supplied to 12 is first slowly stirred at the rotation speed nA for a predetermined period of time in the first region of the aggregate formation pond l12, that is, the first region 112^, by the stirring blade 116A of the stirrer 113^. After that, the stirring blade 116 of the stirrer 113B is transferred to the second region 112B.
It is slowly stirred by B at the rotation speed na for a predetermined period of time, and then transferred to the third region 112G and stirred by the stirrer 113G.
The mixture is slowly stirred by the stirring blade 116G at the rotation speed nc for a predetermined period of time.

118 is a sedimentation tank connected to the flocculation basin 112, which is the final area of the flocculation basin 112, that is, the third area 11.
The suspension supplied from 2C in which aggregates or flocs have been sufficiently formed is allowed to stand still, and the aggregates or flocs are precipitated and removed. 120 is the supply pipe 12
The filtration tank is connected to the outlet of the settling tank 118 through the filter 2, and after removing minute aggregates or flocs that could not be removed in the settling tank 118 by filtration, the treated water is passed through the treated water pipe 124 to the subsequent appropriate water source. It is sent to the equipment.

130 is specifically shown in FIG. 2 or FIG. 6, and indicates the appropriate injection rate WAI of the flocculant into the suspension, the appropriate floccule formation time Tt's at that time, and the appropriate velocity gradient G,'' This is a detection device for detecting water, and is connected to the landing well 102 via a supply pipe 132 and a pump 134, and a drain pipe 133 is opened to an appropriate location such as the mixing pond 106.

Reference numeral 136 designates an IQ device connected to the flow meter 1]8 disposed in the supply pipe 108 and the detection device 130, which determines the appropriate injection rate WA of the m-enricher to the suspension detected by the detection device 130. At that time, the appropriate aggregate formation time Tt", the appropriate velocity gradient GL", the flow N detected by the flow meter 118 (i.e., the amount of supply to the mixing basin 106) Q, and the aggregates measured in advance and input by manual operation etc. Formation pond 1
12 each area 112A.

~, a volume of 112G vA5~. VC and other necessary information, and using this information, the agitators 11 in each region 112A, 112G, 112A, 112G of the aggregate formation pond 112 are adjusted.
3c's rotational speed nA, ~, no are calculated.

That is, the calculation device 136 calculates the appropriate aggregate formation time T18 and the appropriate velocity gradient Gt given by the detection device 130.
' and the aggregate formation time T1 and velocity gradient G1 of the aggregate formation pond 112 (where α is a constant), each region 112A, ~, 11 of the aggregate formation pond 112
The velocity gradient G, (A), ~, G, (c) at 2G is a constant α8° ~, α. using G, (A) = α＾G1 G, (B) = α@G.

G, (c) = αcG.

By defining It is calculated as follows. However, the constant α1. ~． α.

are each region 112A, ~, 112 of the aggregate formation pond 112.
Considering the stirring intensity at G, α^ ≧ α theory ≧ αC, and VAa−+V, a−+Vl! a,” MvA+v, +vc, where each area of the aggregate formation pond 112 ■
2^, ~, 112G is equal volume, that is, V A-V mx
If V a is assumed, there is a relationship α^8+α-+αC2-3 between the constants αA, . . . , αC.

The velocity gradient G, (^), ~, G, (c) is outside the viscosity coefficient of the suspension, the specific gravity η, the drag coefficient C, and the stirring l1113^
.

~, 113C stirring blade ff1lli^, ~, 116
Area of C a A e~, ac and circumferential speed ν, ,~, υ.

and aggregate formation pond 11217) each area 112^, ~, 11
Since it can be expressed using the 2G volume Ja V s , ~, V c , it is possible to calculate from this relationship. Here, stirring blade 116^, ~, 116G
The circumferential speed υ^, ~, υC can be expressed as υ^gon2π"^n^ υBw2π"^n^ υc=2πrA n^ using the number of rotations n^, ~, Ha and radius ra, ~, re. , and even a A V A'e~, ac v
cH koga a^ v^3m8aAπ3 rA'nA'aa v,
3w8aIIπ” r♂n-ac uc”m8ac
Since it can be calculated as π2 r c3 n c2.

Calculate the number of revolutions nA, ~, n6. It can be calculated as Therefore, the number of rotations n□~n is.

It can be calculated as However, T, is (VA +VB +v
C)/Q. As a result, the rotation speed nA, ~+nC
are the appropriate aggregate formation time T and the appropriate velocity gradient Gt' detected by the detection bag GL130, and the aggregate formation time T in the aggregate formation pond 112, (and thus the flowmeter 138).
It can be determined by the flow rate Q) detected by Q).

140 is a controller connected to the calculation bag fi 136, which controls the rotational speed n A + ~, n outputted by the calculation device 136.
Driving means 1 of the stirrers 113^, ~, 113G according to c
Controls the rotation speed of 15^, ~, 115G. 144 is a flocculant supply device, and the calculation device 136 calculates the appropriate injection rate W.
Appropriate injection amount R1 calculated as the product of “AI” and flow rate Q
According to! ! Mixing pond 106 via 2 concentrate additive feed pipe 146
and inject it into a suspension.

Then, the @turbid liquid is collected from the landing well 102 via the pump +34 and the supply pipe 132.1 The detection bag according to the present invention2
At step 1130, the appropriate injection rate WA+'' of the flocculant into the suspension, the appropriate aggregate formation time T-3 and the appropriate velocity gradient QL11 at that time are detected or calculated as described later, and the arithmetic unit ?113[i and sending it out.

In the calculation bag gl 136, each time the appropriate injection rate WA+'' of the flocculant is input from the detection device 130, it is multiplied by the flow mQ input from the flow meter 138 to calculate the actual appropriate injection amount R'' of the flocculant. In addition, each time the appropriate aggregate formation time Tt'' and appropriate velocity gradient G♂ are input from the detection device 1 0, or !iQ is input from the flowmeter 138, the aggregate formation pond is determined as described above. Stirring a113 arranged in each area 112A to 112G of 112
^, ~, 11: Ic rotation speed nA.

~, n( have been calculated.

The appropriate injection amount R8 of the flocculant calculated by the arithmetic unit 136 is provided to the flocculant supply device 144.

The flocculant supply device GL144 injects the flocculant into the mixing pond 106 via the supply pipe 146 according to the appropriate injection amount R1.

The rotation speed nA calculated from the calculation bag gl136, ~.

nc is provided to the controller 140. Controller 140
drives the agitators 113A, 11:Ic of the aggregate formation pond 112, respectively, according to the rotational speed nA, 11:Ic.

By intermittently repeating the detection operation by the detection bag 21130 described above and correcting the agitation control of the aggregate formation pond 112, aggregate formation in the suspension processing device can be performed with appropriate efficiency, and the suspension can be further improved. Processing time can be shortened.

Furthermore, with reference to FIGS. 2 to 5, the detection bag gl1
The configuration of 30 will be explained in detail.

Reference numeral 10 denotes a batch-type stirring tank having an appropriate capacity, for example, Ill, in which a suspension containing a flocculant (hereinafter referred to as
11 (sometimes simply referred to as a suspension) is contained therein. Reference numeral 12 denotes a stirring blade disposed in the stirring tank 10, which is appropriately attached to the free end of the output shaft 16 of a drive means, for example, an electric motor 14, arranged below the Wl stirring tank IO.

I8 is a light emitting device connected to a suitable power source (not shown) by a lead wire 19, and is disposed on the side of the stirring tank IO, and can be used for fluorescent lamps, tungsten lamps, halogen lamps, light emitting diodes, laser light emitting means, etc. The light generated by an appropriate light source is supplied to the suspension 11 in the stirring tank 10 as a parallel beam bundle through an appropriate optical system, for example, a slit.

20 is a phototransistor and a photodiode.

A light receiving device containing a suitable photoelectric conversion element such as CdS or CCD as a light receiving means is arranged on the side of the stirring tank IO, and is a light emitting device! ! The light provided by the light emitting device 18 which receives the light supplied as a parallel beam at t18 via the suspension 11.

The light receiving device 20 receives scattered light or attenuated transmitted light because it is scattered or blocked by the aggregates or flocs 17 in the suspension 11.

The light receiving device N20 includes a light emitting device 18 to receive transmitted light.
The light emitting device 18 may be placed at a predetermined angle with respect to the parallel beam from the light emitting device 18 in order to receive scattered light. In order to simplify the explanation, it is assumed below that the light receiving device 20 is opposed to the light emitting device 18. Also the second
In the figure, only one set of the light emitting device 2118j5 and the light receiving device 20 is arranged, but the invention is not limited to this.
A plurality of sets of the light emitting device 18 and the light receiving device 20 may be arranged.0 The light emitting device i18 and the light receiving device M20 may form an aggregate, that is, a flock 1, especially if they are arranged on the same horizontal plane.
This is convenient for detecting the sedimentation state of No. 7 with high accuracy.

Reference numeral 22 denotes a measuring device connected to the light receiving device N20 via a lead wire 21, which measures the light if (hereinafter referred to as "received light amount") (2) received by the light receiving device 20. Plus measuring equipment! ! 12
2 is the range of variation (i.e., the predetermined value! , and ■□) ΔI and the fluctuation period F are determined and output.

24 is a supply pipe whose one end is opened to the stirring tank 10 via an on-off valve 25, and the other end is communicated with the supply pipe 132 (see Fig. 1); 26 is a supply pipe whose one end is connected to the flocculant supply source 28; This is a flocculant supply pipe with one end communicating with the other, and the other end opening into the stirring tank 10 via an on-off valve 27 . Reference numeral 30 denotes a drain pipe, one end of which is opened at the bottom of the stirring tank IO, and the other end communicated with the drain pipe 133 via the on-off valve 2.
Remove the detected suspension 11 from (see Figure 1), 3
4 is a dark box with at least a stirring tank 10. It houses a light emitting device 18 and a light receiving device 20, and eliminates the influence of external light.

36 is a drive means 14, a measuring device 22, and an on-off valve 25.27
The driving means 14 gives the circumferential speed υ or the rotational speed n of the stirring blade 12, and the measurement device 22 calculates the fluctuation range of the received light amount Ii (τ) and the received light amount ■. A fluctuation period F is given, and a supply amount M of the suspension liquid and a supply amount N of the flocculant are given from the on-off valves 25 and 27. The calculation device 36 calculates parameters useful for determining the state of formation of aggregates, that is, flocs 17.

That is, the arithmetic unit 36 uses the fluctuation width Δ■ (volts) of the amount of received light I and the constant α to calculate the aggregate, that is, the floc 17.
The diameter d (c) is calculated as d=αΔI, and the fluctuation period F (seconds) of the received light amount
Using the circumferential speed υ (17 seconds) or rotational speed n (1/second) of 2 and constants β and β°, calculate the number N of aggregates, that is, flocs 17.
b (1/am3) is calculated, and the diameter d (c) and the number Nb (1/am3) of the aggregate, that is, the floc 17, are constant a.
(using
cm') is calculated as V=@d'N1°, and the initial concentration of suspended matter in the suspension W s * (■g/view) determined from the received light amount it (τ) (volts) and the supply IkM, N The flocculant injection rate determined from WA Emperor (sg/
u), the diameter d (c■) of the aggregates or flocs 17, the number Nb (1/c■3), the constant γ, and the coefficient a specific to the flocculant to calculate the effective density ρ of the aggregates or flocs 17.
(g/cm3), and if desired, time T and constant δ
The sedimentation velocity S(
Using the received light ff1xr(τ) and a constant input, calculate the supernatant water turbidity τ (degrees) after the aggregates, that is, floc 17, have settled as τ = input xrCτ). ing. Here, the relationship between the parameters calculated by the arithmetic unit 36 and the actual aggregation state of the aggregates, that is, the flocs 17, is the diameter d or the number Nb, and the body tav.

Effective density p, sedimentation velocity S, supernatant water turbidity are closely related in this order, so if it is desired to accurately detect the flocculation state of flocs 17, it is sufficient to use the latter parameter. Furthermore, if it is desired to detect the agglomeration state more precisely, a combination of a plurality of parameters may be used.Incidentally, the arithmetic unit Colo may be configured not to calculate parameters that are not used.

8 is another arithmetic device connected to the arithmetic device 36.

The diameter d, the number Nk, the body 8&v, and the effective density ρ of the aggregate or floc 17 calculated by the calculation device 36.

At least one of the sedimentation speed S and the supernatant water turbidity τ after the flocs 17 have settled is stored in sequence for the flocculant injection rate WAI at that time,
At this time, the appropriate value of the injection rate of the flocculant to the suspension (that is, the appropriate injection rate) WAt is calculated.In other words, the calculation unit 8 calculates the injection rate of the flocculant to the suspension. The diameter d9 of the flocculent, that is, the floc 17, changes with respect to the change in the flocculant injection rate WAI (given from the calculation device Colo) calculated by the amount M and the flocculant supply amount N.
Coagulant is injected* in response to when the volume V or effective density ρ begins to change sharply, and the number Nk, sedimentation rate S, or supernatant water turbidity τ starts to change slowly.
The WAI is determined to be the appropriate injection rate WA, and this is determined by the calculation device 1.
36 (see Figure 1).

Furthermore, the arithmetic unit 38 calculates a number N corresponding to the appropriate injection rate WA
After setting b to the appropriate number N-, the circumferential speed υ and rotation speed n of the stirring blade 12 corresponding to the appropriate number N- are respectively the appropriate circumferential speed υ.
1j5 and the appropriate rotational speed n''', and when detecting the subsequent appropriate aggregate formation time TL'', it is applied to the driving means 14 to drive the stirring blade 12 during slow stirring to the appropriate circumferential speed υ8 and, as a result, the appropriate rotational speed n1. Rotate slowly with .

In addition, the calculation device 38 calculates the volume of the stirring tank 10 (here, M
+N), the viscosity coefficient of the suspension, the specific gravity η, and the drag coefficient C
Using the surface ga of the stirring blade 12 and the appropriate circumferential speed 11, the appropriate speed gradient G,1 is calculated, and this is calculated by the calculation device 13.
6 (see Figure 1).

Reference numeral 39 denotes a control device disposed between the on-off valve 25 and the arithmetic unit M38 and the on-off valve 27, which controls the opening/closing time of the on-off valve 25, the suspension supply amount M, and the appropriate injection rate wA given by the arithmetic unit 38. , ``W'' is the time to open the on-off valve 27 so that the product M W A I '' and the supply amount N of the flocculant match.

40 is another measuring device connected to the measuring device 22;

While the flocculant is injected into the suspension in the stirring tank 10 according to the appropriate injection rate WAI given from the computing device 2t38, the driving means 14 moves the stirring blade 12 at an appropriate circumferential speed υ1 and hence at an appropriate rotational speed n. While driving the stirring blade 12 to perform slow stirring, the measuring device aZ
Time t4 when the amount of received light I measured by Z becomes flat
The time required for the formation of aggregates, that is, the aggregate formation time Tt, is determined and outputted to the arithmetic unit !36 as the appropriate aggregate formation time TL'' (see FIG. 1).

In addition, with reference to FIGS. 2 to 5, the detection device 13
The effect of 0 will be explained in detail.

After the on-off valve 32 is opened and the remaining suspension 11 in the stirring tank IO is removed via the drain pipe 30, the on-off valve 32 is closed.

The on-off valve 25 is opened for a predetermined period of time, and a predetermined MM (for example, 1×) of suspension is collected from a suspension supply source (not shown) via the supply pipe 24 and supplied into the stirring tank IO. do.

When the supply of the suspension into the stirring tank 10 is completed, 1 time t,
At this point, the stirring blade 12 begins to rotate rapidly, that is, at a high speed, by the driving means, for example, the electric motor 14.

Thereafter, at time t2, the on-off valve 27 is opened for a predetermined period of time, so that a predetermined amount N of flocculant is released.

The coagulant is injected from the flocculant supply source 28 into the stirring tank IO via the aggregation agent supply pipe 26. As the flocculant, known flocculants such as polyaluminum chloride may be used as desired.

1 light emitting device 1 prior to the start of rapid rotation of the stirring blade 12
8. The light receiving device 20 and the measurement wave W122 have been started, and the amount of received light transmitted through the suspension in the stirring tank 10 is
is measured and provided to the arithmetic unit 36.

The amount of light received until time t2, that is, the time when the flocculant is supplied, is the initial concentration W0 of suspended matter contained in the suspension.
When a predetermined amount N of flocculant is injected at time t2, which is a constant value τ) corresponding to Since the liquid 11 is being rapidly stirred and moved in the stirring tank lO, the light receiving device! The amount of received light (2) of 120 increases slowly.

At time t, when the stirring blade 12 starts to be rotated at a slow speed, that is, at a low speed, aggregates or flocs 17 are further formed in the suspension 11, and the diameter d of the flocs 17 gradually increases, and the suspension 11 is slowly stirred and moved in the stirring tank IO, so the amount of light received by the light receiving device 20 increases and decreases little by little, but increases as a whole.

When time t4 is reached, the flocs 17 are sufficiently agglomerated in the suspension 11 and the diameter d does not change, and the suspension 11 is being stirred and moved slowly in the stirring tank 1G. , the amount of light received by the light receiving device 20 becomes flat, and as the aggregates, ie, the flocs 17, pass, it begins to periodically fluctuate between a predetermined value (■) and 11.

Furthermore, time 1. When the rotation of the stirring blade 12 is stopped to stop stirring, the flocs 17 formed in the suspension ll start to settle, so the amount of light I received by the light receiving device @20 increases and decreases little by little. However, at time t, the amount of received light ■ reaches a constant value Ir( τ)
maintain.

For example, when using a kaolin suspension prepared by adding 25 g of kaolin to fresh water of Ill, and injecting polyaluminum chloride at an injection rate of 15 mg/i, the measuring device 22 measures the amount of light received by the light receiving device 20. The measurements were as shown in Figure 3.

Thereafter, the calculation device Coro calculates the diameter d, the number Nb1 bodies @V, and the effective density ρ of the flocs 17 as described above, and further calculates the sedimentation velocity S and supernatant water turbidity τ if desired. do. As described above, the state of formation of the aggregates, that is, the flocs 17, can be detected using these parameters calculated by the arithmetic unit Colo.

The calculation device 8 calculates at least one of the diameter d, the number Nb2 volume V, the effective density ρ, the sedimentation rate S, or the supernatant water turbidity τ of the flocs 17 calculated by the calculation device 36 as desired. It is memorized with respect to the flocculant injection rate WAI, and when the change in the diameter av or effective density ρ of the flocs 17 starts to become steep, or when the number Nb, the sedimentation rate S or the supernatant water turbidity τ changes. The injection rate WAI of the flocculant at which the rate starts to become slow is determined as the appropriate injection rate WAI, and is output to the arithmetic unit 136 (see FIG. 1).

The basis for this will be explained in more detail. For example, t
! Each time the above measurements and calculations are repeated using a kaolin suspension prepared by adding 25 g of kaolin to L. Calculate ρ and determine the flocculant injection rate WA
When plotted against I, Figure 4 was obtained.

Similarly, using the kaolin suspension, each time the above-mentioned measurements and calculations are repeated, 1 aggregate or floc
When the effective density ρ, sedimentation rate S, and supernatant water turbidity τ of No. 7 were calculated and plotted against the flocculant injection rate WAI, FIG. 5 was obtained.

As is clear from FIGS. 4 and 5, as the flocculant injection rate WAI changes, the flocs 1
The diameter d of 7, the number of Nb9 bodies v, the effective density ρ, the sedimentation rate S, and the supernatant water turbidity τ are changed. To be more specific, the flocculant injection rate WAI is set to a predetermined value WAI'' (here, 301
g/cross), the number N of aggregates, that is, flocs 17, does not change much, but the diameter d and volume V become relatively large, the effective density ρ decreases, and the aggregate becomes unstable. In other words, it can be determined that flocks 17 are formed. Further, when the injection rate WA1 of the flocculant exceeds the predetermined value WA,'1, the flocculent, that is, the floc 17
Even if the settling velocity S or the L clear water turbidity τ after settling of the flocs 17 does not change much, and even if the flocculant injection rate WA1 exceeds the predetermined value WAI'', the flocculant injection amount increases. It can be determined that the amount of flocculation, that is, floc 17, cannot be increased compared to the above.
Undesirable.

On the other hand, the flocculant injection rate WAI is the predetermined value WAI''
, the aggregate or floc 1
The number Nk of 7 becomes extremely large, and its diameter d and volume V
The effective density ρ has also become extremely small, and it can be concluded that relatively stable aggregates, that is, flocs 17 have been formed. However, at this time, the settling velocity S of the flocs 17 is small, and the supernatant water turbidity τ after the flocs 17 has settled is large.
Furthermore, if the flocculant injection rate WAI becomes significantly smaller than the predetermined value WA-, it can be determined that the flocculant, that is, the flocs 17, cannot be efficiently precipitated and removed even if the flocculant injection amount can be reduced. Undesirable.

Therefore, if the predetermined value WA+'' at this time is used as the flocculant injection rate, the amount of flocculant injection can be reduced and the amount of flocculation and sedimentation of suspended matter in the suspension can be maintained at a relatively large value.
Floating substances in a suspension can be efficiently coagulated and precipitated and removed.

For this purpose, the arithmetic unit 138 determines W□1 as the appropriate injection rate of the flocculant, as described above.

When the arithmetic unit 38 determines the appropriate injection rate wA,'', the arithmetic unit 38 determines the appropriate circumferential speed υ1 of the stirring blade 12 and the appropriate rotational speed n'' correspondingly, and determines the appropriate rotational speed n'' of the stirring blade 12. 4, and then calculates an appropriate velocity gradient G♂ and sends it to the arithmetic unit 136 together with the appropriate injection rate WAI'' (see FIG. 1).

@When the calculation device Ko8 outputs “appropriate injection rate WAI”,
Suspension 11 of the detection method in the stirring tank IO via the on-off valve 2
is removed, the on-off valve 25 is opened and the flocculant is supplied into the stirring tank 10 and the flocculant is supplied through the on-off valve 27 to the suspension being rapidly stirred by the stirring blades 12 at an appropriate injection rate WAI. is injected.

Thereafter, the driving means 14 controls the stirring blade 12 to perform slow stirring at the appropriate circumferential speed υ1 or the appropriate rotational speed n8 calculated by the calculation unit W138 in accordance with the appropriate injection rate WA♂.

In this state, the amount of received light I is measured using the measuring device M22.
Next, in the measurement device 140, the time from the start time 〇 of the slow stirring to the time t4 at which the received light amount I measured by the measurement device fi22 becomes flat, that is, the aggregate formation time Tt.
is detected, and the arithmetic unit 1 determines the appropriate aggregate formation time TL.
36 (see Figure 1).

In the above description, the detection device 11 includes only one stirring tank IO.
3G was explained, but with this, it takes a lot of time to detect the agglomeration state, and as a result, the appropriate injection rate wA.
Since it takes time to detect the appropriate aggregate formation time T♂ and the appropriate velocity gradient Gt'', a plurality of stirring tanks (four in this case) may be arranged side by side as shown in FIG.

The detection device 21130 in FIG.
Measuring device i! Except for the fact that 140 is made common, the configuration and operation are substantially the same as the detection device shown in FIG. The same reference numerals as those given in the detection device will be given, and detailed explanation thereof will be omitted. The on-off valve 2 has the symbols A, 'B, C, and D added to the reference number to distinguish between the stirring tanks arranged side by side.
7A to 27D are open for different times, and are stirring tanks 10A.

The injection rate of the flocculant to the suspension 11^ in ~, 100, ~, 110 is adjusted.

When the appropriate injection rate W11 is determined by the calculation device 13g, the control device! 139, the flocculant is injected into the suspension being rapidly stirred in the stirring tank 10A to achieve this appropriate injection rate WAI'', and the agitating blade is injected at the appropriate circumferential speed υ1 outputted from the calculation device !38 and the appropriate rotational speed n1. 12A is slowly stirred, the amount of received light! is measured by the measuring device a22A, and further, the proper aggregate formation time T♂ is measured by the measuring device 40 from the amount of received light I at this time.

Further, the calculation device 38 calculates the appropriate speed gradient G♂ using the appropriate circumferential speed υ1 calculated corresponding to the appropriate injection rate WAl'' and the appropriate rotational speed n1.

In the detection device 130 of FIG. 6, a fifth stirring tank may be additionally arranged and used only for measuring the appropriate aggregate formation time T♂, according to which - waste treatment It can save time.

In the above description, the calculation device ko8 calculates the appropriate injection rate WAI'' and the appropriate circumferential speed υ8 (and therefore the appropriate rotational speed n
After determining 8) and calculating the appropriate velocity gradient GL, the suspension is supplied to the stirring tank IO or 10^ again, and a test is performed to detect the appropriate aggregate formation time T♂. However, in the calculation device 38 or another calculation type N (not shown), the appropriate aggregate formation time TC is determined from past data of the appropriate injection rate WAI'' and the appropriate velocity gradient G♂, and the calculation type 22136 is calculated. The same action or effect can be achieved even if the direction is modified to send out.

In addition, in the above description, the appropriate velocity gradient GL'' and the appropriate aggregate formation time T correspond to the appropriate injection rate WAl'' of the flocculant.
Although the agitation control of the aggregate formation pond 112 is carried out in order to obtain the Instead of the aggregate formation time T♂, the velocity gradient Gt and lJ aggregate formation time T, which do not yet fully optimize the aggregation state of the suspension, may be used, that is, as shown in FIG. 2 or 6. After determining the appropriate injection rate WA- of the flocculant, the amount of received light is reduced by simply stirring the flocculant-injected suspension at this appropriate injection rate WAI at a slow speed in a stirring tank to form aggregates. The gradient GL may be determined at a speed corresponding to this slow stirring, and the aggregate formation time TL may be determined from the amount of light received.

In addition, in the above description, the stirrers 113A, -, 11:I
Although the agitation control of the aggregate formation pond 112 is executed by controlling the rotation speed n A + ~, ne of the agitator 113A, the present invention is not limited to this.
, ~, 113G rotation speed or aggregate formation pond 112
Aggregate formation pond 11 by controlling the volume of C.
A stirring control of 2 may be achieved.

(3) Effects of the Invention As is clear from the above, the first stirring control method of the flocculation pond according to the present invention involves injecting the flocculant into the suspension while rapidly stirring the mixture in the mixing basin.

In particular, there is a method for controlling agitation in an aggregate formation pond in which aggregates are formed by slow stirring in the aggregate formation pond.

(a) A first step of injecting a flocculant into the suspension collected upstream of the mixing pond and stirring it in a stirring tank.

(b) a second step of stirring the flocculant-injected suspension in the first step at a stirring speed lower than that of the first step; and a third step of measuring the amount of light received by the light emitting device through the suspension into which the flocculant was injected in the step.

(d) A fourth step of detecting the agglomeration state of the suspension into which the flocculant was injected in the first step from the amount of received light measured in the third step.

(e) a fifth step of determining an appropriate injection rate of the flocculant in accordance with the agglomeration state detected in the fourth step; and (f) a speed corresponding to the appropriate injection rate determined in the fifth step. a sixth step of determining the agglomerate formation time of the gradient and the suspension injected with the flocculant in the first step;

(g) a seventh step of detecting the amount of suspension supplied to the mixing basin; (1) the velocity gradient and aggregate formation time determined in the sixth step and the relationship detected in the seventh step; an eighth step of controlling the agitation in the aggregate formation pond using the supply amount of the suspension liquid and the eight pumps of the aggregate formation pond; (1) supply of the suspension detected in the seventh step; a ninth step of calculating the injection amount of the flocculant from the amount and the appropriate injection rate of the flocculant determined in the fifth step; (j) the mixing according to the injection amount calculated in the ninth step; and a tenth step of injecting a flocculant into the pond.

(+) It has the effect of eliminating the tester's visual observation and experience, and in turn (u)! This has the effect of optimizing the stirring control of the aggregate formation pond in a short time while avoiding actually measuring the result of the stirring process in the II aggregate formation pond.

Another method of controlling agitation in the flocculation pond according to the present invention is to inject the flocculant into the suspension while rapidly stirring it in the mixing basin, and then slowly stirring it in the flocculation basin. A method for controlling agitation of an agglomerate formation pond in which agglomerates are formed by: (a) injecting a flocculant into a suspension collected upstream of the mixing pond and injecting the flocculant into the agitation tank; (b) a second step of stirring the flocculant-injected suspension in the first step at a lower stirring speed than in the first step; and (c) at least and a third step of measuring the amount of light received by the light receiving device from the light emitting device via the liquid mixture created in the first step in the second step.

(d) A fourth step for detecting the aggregation state of the suspension into which the flocculant was injected in the first step from the amount of received light measured in the third step.
With the process.

(e) a fifth step of determining an appropriate injection rate of the flocculant according to the agglomeration state detected in the step t54; and (f) a velocity gradient corresponding to the appropriate injection rate determined in the fifth step. and (g) a seventh step of determining, from among the velocity gradients determined in the sixth step, a velocity gradient that makes the agglomeration state detected in the fourth step appropriate as the appropriate velocity gradient. With the process.

(h) In accordance with the appropriate velocity gradient determined in the seventh step, the aggregate formation time of the suspension into which the flocculant was injected in the first step is determined, and the eighth step is determined as the appropriate aggregate formation time. (+) a ninth step of detecting the amount of suspension supplied to the mixing pond; and (j) determining the appropriate velocity gradient determined in the seventh step and the appropriate coagulation determined in the eighth step. (k) a tenth step of controlling the agitation in the aggregate formation pond using the aggregate formation time, the supply amount of the suspension detected in the ninth step, and the volume of the aggregate formation pond; an 11th step of calculating the injection amount of the flocculant from the supply amount of the suspension detected in the step 9 and the appropriate injection rate of the flocculant determined in the fifth step; and a twelfth step of injecting a flocculant into the mixing basin according to the amount of injection calculated in the step, so in addition to the effects of (+) (i1) above, (
ii1) It not only detects the appropriate injection rate but also determines the appropriate velocity gradient and appropriate aggregate formation time, which has the effect of shortening the time required for stirring control of the aggregate formation pond.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an actual suspension processing apparatus in which agitation control of an agglomerate formation pond is executed according to an embodiment of the agitation control method for an agglomerate formation pond according to the present invention, and FIG. In order to carry out an embodiment of the invention, the detection device shown in FIG. 1 detects the appropriate injection rate WAI of the flocculant into the suspension, the appropriate aggregate formation time T♂ and the appropriate velocity gradient GL at that time. A cross-sectional view specifically showing an example of the
An operation explanatory diagram for explaining the operation of the detection device shown in Fig. 4. Diameter d of the aggregate obtained from the operation explanatory diagram in Figure 3.
, number Nb, volume V, effective density ρ, and flocculant injection rate W
Figure 5 is a graph showing the relationship between
FIG. 6 is a sectional view showing a detection device in which four of the detection devices of FIG. 2 are arranged side by side.

Claims (12)

[Claims] (1) In an agitation control method for an aggregate formation pond, in which a flocculant is injected into a suspension while being rapidly stirred in a mixing basin, and then aggregates are formed by slow stirring in an aggregate formation basin. , (a) a first step of injecting a flocculant into the suspension collected upstream of the mixing pond and stirring it in a stirring tank, and (b) a lower concentration than the first step. a second step of stirring the suspension into which the flocculant was injected in the first step at an agitation speed; (c) at least during the second step, the suspension into which the flocculant was injected in the first step; (d) measuring the amount of light received from the light emitting device to the light receiving device via the light emitting device; The fourth part detects the state of liquid aggregation.
(e) a fifth step of determining an appropriate injection rate of the flocculant according to the agglomeration state detected in the fourth step; a sixth step of correspondingly determining the velocity gradient and the agglomerate formation time of the suspension into which the flocculant was injected in the first step; (g) a step of detecting the amount of suspension supplied to the mixing pond; (h) Using the velocity gradient and aggregate formation time determined in the sixth step, the supply amount of the suspension detected in the seventh step, and the volume of the aggregate formation pond. an eighth step of controlling agitation in the flocculation pond; and (i) based on the supply amount of the suspension detected in the seventh step and the appropriate injection rate of the flocculant determined in the fifth step. and (j) a tenth step of injecting the coagulant into the mixing pond according to the injection amount calculated in the ninth step. A stirring control method for an aggregate formation pond, characterized by: (2) (i) In the fourth step, the aggregation state of the suspension is detected by calculating the number of aggregates from the fluctuation period when the amount of received light becomes flat and the stirring speed in the second step. and (ii) in the fifth step, the injection rate of the flocculant corresponding to when the change in the number of aggregates starts to slow down is determined as the appropriate injection rate. A method for controlling agitation in an aggregate formation pond according to item (1). (3) (i) In the fourth step, by calculating the diameter of the aggregate from the fluctuation range when the amount of received light is flattened,
Detecting the flocculating state of the suspension, and (ii) determining, in the fifth step, the injection rate of the flocculant corresponding to when the change in the diameter of the aggregate starts to become steep as the appropriate injection rate. A stirring control method for an aggregate formation pond according to claim (1), characterized in that: (4) (i) In the fourth step, calculate the number of aggregates from the fluctuation period when the amount of received light is flattened and the stirring speed in the second step, and the width of fluctuation when the amount of received light is flattened. (ii) detecting the aggregation state of the suspension by calculating the diameter of the aggregates from the aggregates and calculating the volume of the aggregates from the number and diameter of the aggregates; The injection rate of the flocculant that corresponds to when the change in the number of aggregates begins to slow down, the diameter of the aggregates begins to change sharply, and the volume of the aggregates starts to change sharply is determined as the appropriate injection rate. A stirring control method for an aggregate formation pond according to claim (1), characterized in that: (5) (1) In the fourth step, calculate the number of aggregates from the fluctuation period when the amount of received light is flattened and the stirring speed in the second step, and the width of fluctuation when the amount of received light is flattened. The aggregation state of the suspension can be determined by calculating the diameter of the aggregates from the above, and calculating the effective density of the aggregates from the number and diameter of the aggregates, the suspended solids concentration of the suspension, and the injection rate of the flocculant. and (ii) in the fifth step, the injection rate of the flocculant corresponding to when the change in the number of aggregates starts to slow down and the change in diameter and effective density starts to become steep is determined as the appropriate injection rate. Claim No. (1) characterized in that:
A stirring control method for an aggregate formation pond as described in . (6) In an agitation control method for an agglomerate formation pond, in which a flocculant is injected into a suspension while being rapidly agitated in a mixing pond, and then agglomerates are formed by slow stirring in an agglomerate formation pond. , (a) a first step of injecting a flocculant into the suspension collected upstream of the mixing pond and stirring it in a stirring tank, and (b) a lower concentration than the first step. a second step of stirring the suspension into which the flocculant was injected in the first step at an agitation speed; (c) at least during the second step, the suspension into which the flocculant was injected in the first step; (d) measuring the amount of light received from the light emitting device to the light receiving device via the light emitting device; The fourth part detects the state of liquid aggregation.
(e) a fifth step of determining an appropriate injection rate of the flocculant according to the agglomeration state detected in the fourth step; (g) Among the velocity gradients determined in the sixth step, a velocity gradient that makes the agglomeration state detected in the fourth step appropriate is determined as an appropriate velocity gradient. (h) Corresponding to the appropriate velocity gradient determined in the seventh step, calculate the aggregate formation time of the suspension in which the flocculant was injected in the first step, and determine the appropriate velocity gradient. (i) a ninth step of detecting the amount of suspension supplied to the mixing pond; (j) determining the appropriate velocity gradient determined in the seventh step; A step of controlling the agitation in the aggregate formation pond using the appropriate aggregate formation time determined in step 8, the supply amount of the suspension detected in the ninth step, and the volume of the aggregate formation pond. (k) an eleventh step of calculating the injection amount of the flocculant from the suspension supply amount detected in the ninth step and the appropriate injection rate of the flocculant determined in the fifth step; and (l) a twelfth step of injecting a flocculant into the mixing pond according to the injection amount calculated in the eleventh step. Method. (7) (i) In the fourth step, calculate the supernatant water turbidity after the aggregates have been precipitated from the amount of light received when the amount of light received becomes flat after the stirring in the second step is stopped. (ii) In the fifth step, the injection rate of the flocculant corresponding to when the change in supernatant water turbidity starts to become slow is determined as the appropriate injection rate. Claim No. 1 characterized in that (
6) Agitation control method for an aggregate formation pond as described in section 6). (8) (i) In the fourth step, the aggregation state of the suspension is determined by calculating the sedimentation rate of the aggregate from the time until the amount of received light becomes flat after the stirring in the second step is stopped. and (ii) in the fifth step, the injection rate of the flocculant corresponding to when the change in the sedimentation rate of the aggregates starts to become slow is determined as the appropriate injection rate. A method for controlling agitation in an aggregate formation pond according to item (6). (9) (i) In the fourth step, the number of aggregates is calculated from the fluctuation period when the amount of received light measured in the third step becomes flat and the stirring speed in the second step. It is characterized by detecting the flocculating state of the turbid liquid, and (ii) determining the injection rate of the flocculant corresponding to when the change in the number of aggregates starts to slow down in the fifth step as the appropriate injection rate. The scope of claim No. (
6) Agitation control method for an aggregate formation pond as described in section 6). (10) (i) In the fourth step, the aggregation state of the suspension is detected by calculating the diameter of the aggregate from the range of fluctuation when the amount of received light measured in the third step becomes flat. ,
and (ii) in the fifth step, the injection rate of the flocculant corresponding to when the change in diameter of the aggregate starts to become steep is determined as the appropriate injection rate.
6) Agitation control method for an aggregate formation pond as described in section 6). (11) (i) In the fourth step, calculate the number of aggregates from the fluctuation period when the amount of received light becomes flat after the stirring in the second step is stopped and the stirring speed in the second step. , and by calculating the diameter of the aggregates from the variation range when the amount of received light measured in the third step is flattened, and by calculating the volume of the aggregates from the number and diameter of the aggregates, the suspension is detecting the aggregation state of the liquid, and (ii) in the fifth step, the change in the number of the aggregates starts to slow down, the diameter of the aggregates starts to change steeply, and the volume of the aggregates starts to change slowly; The agitation control method for an aggregate forming section according to claim 6, characterized in that the injection rate of the flocculant corresponding to when the change starts to become steep is determined as the appropriate injection rate. (12) (i) In the fourth step, the fluctuation period and the second
Calculate the number of aggregates from the stirring speed in the third step, calculate the diameter of the aggregates from the fluctuation width when the amount of received light measured in the third step becomes flat, and calculate the number and diameter of the aggregates. (ii) in the fifth step, the aggregation state of the suspension is detected by calculating the effective density of the aggregates from the suspended matter concentration of the suspension and the injection rate of the flocculant; Claim (6) characterized in that the injection rate of the flocculant corresponding to when the change in the number starts to slow down and the change in diameter and effective density start to become steep is determined as the appropriate injection rate. The agitation control method for the aggregate formation pond described above.