JPH0418883B2 - - Google Patents

Description

Detailed Description of the Invention (1) Purpose of the Invention [Field of Industrial Application] The present invention relates to a method for controlling the injection of a flocculant, and in particular, the present invention relates to a method for controlling the injection of a flocculant, and in particular, the present invention relates to a method for controlling the injection of a flocculant. A coagulation method that optimizes the injection rate or amount of coagulant by creating an injection control formula while updating the appropriate injection rate of coagulant for the liquid, and managing the injection of coagulant using the injection management formula. This invention relates to a method for managing the injection of drugs.

[Prior Art] Conventionally, the injection control method for this type of flocculant was to collect an appropriate amount of a suspension of tap water, industrial water, sewage, industrial waste, etc. and distribute it in equal amounts to multiple beakers. Afterwards, each flocculant is injected while varying the injection rate, stirred and left to stand, and the tester visually observes the flocculant state and determines the appropriate injection rate by observing the agglomeration state through experience. A method was proposed to control the injection rate to an appropriate level.

[Problems to be solved] However, in the conventional flocculant injection control method, the flocculation rate for the suspension is determined based on the results of determining the appropriate injection rate by observing the flocculation state through visual observation and experience of the tester. Since the injection rate of the flocculant was controlled, (i) the detection result of the flocculant state differed depending on the tester, and (ii) the detection of the flocculant state and, in turn, the determination of the flocculant injection rate had the drawbacks. This method has the disadvantage that it requires a lot of time, and furthermore, (iii) the injection rate of the flocculant cannot necessarily be optimized.

Therefore, in order to eliminate these drawbacks, the present invention creates an injection management formula while updating the appropriate injection rate of the flocculant according to the turbidity range of the suspension.
It is an object of the present invention to provide a flocculant injection management method that optimizes the flocculant injection rate or amount by controlling the flocculant injection using the injection management formula.

(2) Structure of the invention [Means for solving the problems] The means for solving the problems provided by the present invention are: (a) the first step of collecting the suspension; and (b) the turbidity of the suspension. (c) determining the appropriate injection rate of the flocculant for the suspension collected in the first step in accordance with when turbidity is detected in the second step; (d) determining the turbidity intermittently at a frequency less than or equal to the frequency at which turbidity is detected in the second step; a fourth step of storing the appropriate injection rate determined in the third step in place of the oldest stored value; (e) storing the appropriate injection rate stored in the fourth step and the appropriate injection rate determined in the fourth step; a fifth step of creating an injection management formula using the turbidity detected in the second step when the injection rate is determined in the third step, and storing it in place of the previous injection management formula; (f) a sixth step of calculating the injection rate of the flocculant according to the injection control formula according to the turbidity detected in the second step; (g) a sixth step of calculating the injection rate of the flocculant according to the injection rate calculated in the sixth step A seventh step of injecting a flocculant into a suspension to be treated.

It is.

[Function] The flocculant injection management method according to the present invention has the following effects as specified in the section of [Means for solving problems] above.
Determine the turbidity of the suspension and the appropriate injection rate of the coagulant for that turbidity, and store the appropriate injection rate determined according to the turbidity range to which the turbidity belongs in place of the oldest memorized value. Create an injection control formula using the appropriate injection rate calculated and store it in place of the previous injection control, calculate the flocculant injection rate using the injection control formula according to the turbidity of the suspension, and use the calculated injection rate. Since the flocculant is injected into the suspension to be treated according to the turbidity, (i) it eliminates the visual observation and experience of the tester, and (ii) the injection control formula can be adjusted to a certain turbidity. It functions to prepare according to the range, and (iii) to optimize the injection rate or injection amount of the coagulant according to the latest detection results.

[Example] Next, a flocculant injection management method according to the present invention will be specifically described with reference to the accompanying drawings.

(Explanation of the attached drawings) FIG. 1 is a sectional view showing an actual suspension processing apparatus in which injection of a flocculant is controlled by an embodiment of the flocculant injection management method according to the present invention. It is.

FIG. 2 shows an appropriate method for determining an appropriate injection rate of a flocculant included in the suspension processing apparatus shown in FIG. FIG. 3 is a cross-sectional view showing the injection rate determining device.

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

Figure 4 shows the diameter d, number n, volume V, and effective density ρ of the aggregates obtained from the operation diagram shown in Figure 3.
FIG. 3 is a graph diagram showing the relationship between and the injection rate W _A1 of the flocculant.

Figure 5 shows the relationship between the supernatant water turbidity τ, flocculation velocity S and effective density ρ, and the flocculant injection rate W _A1 , which were obtained from the operation diagram shown in Figure 3. It is a graph diagram.

FIG. 6 is a sectional view showing an appropriate injection rate determination device in which four of the appropriate injection rate determination devices shown in FIG. 2 are arranged side by side.

FIGS. 7a to 7c are graphs showing the results of flocculant injection management in the suspension processing apparatus shown in FIG. 1 according to an embodiment of the flocculant injection management method according to the present invention. It is.

(Configuration of Suspension Liquid Treatment Apparatus) First, referring to FIG. The configuration of the processing device will be explained in detail.

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).

106 is a coagulant mixing pond that 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 (for example, an electric motor) 109. .

112 is an aggregate formation pond that is communicated with the mixing pond 106 via a supply pipe 114, and is divided into three regions 112A, 112C,
Each drive means (e.g. electric motor) 115
Stirring blades 116A, . . . , 116C are provided which are slowly rotated by blades A, .about., 115C. The mixed liquid of the flocculant and the suspension formed in the mixing pond 106 and supplied to the flocculation basin 112 through the supply pipe 114 is first stirred in the first region 112A of the flocculation basin 112. It is slowly stirred by the blade 116A for a predetermined period of time, and then moved to the second area 112B and stirred by the stirring blade 116.
B, the stirring blade 116 is slowly stirred for a predetermined time, and then transferred to the third region 112C.
The mixture is slowly stirred by C for a predetermined period of time.

118 is a sedimentation tank connected to the flocculation basin 112, in which the flocs (i.e., flocs) supplied from the third region 112C of the flocculation basin 112 are mixed with a sufficiently formed suspension. The mixed solution with the flocculant is allowed to stand, and the flocs are precipitated and removed.

120 is connected to the sedimentation tank 118 via the supply pipe 122
A filtration basin connected to the outlet of the sedimentation basin 1.
After removing minute aggregates (ie, flocs) that could not be removed in step 18 by filtration, the treated water is sent to subsequent appropriate equipment via treated water pipe 124.

Reference numeral 130 is a device for determining the appropriate injection rate of the flocculant shown in FIG. 2 or FIG.
2, and the outlet portion is open to the mixing basin 106 etc. via a drain pipe 133.

Reference numeral 136 is a calculation device connected to the appropriate injection rate determination device 130, which calculates the turbidity τ of the suspension (that is, the turbidity meter 138 attached to the supply pipe 132 or other turbidity attached to the supply pipe 108). In accordance with the magnitude of the turbidity τ ₀ ) of the suspension measured by the turbidity meter 139, a storage location for the appropriate injection rate W _A1 ^* of the flocculant determined by the appropriate injection rate determination device 130 is selected. There is.
That is, the calculation device 136 determines whether the turbidity of the suspension τ ₀ is in a range smaller than the predetermined value τ ₀ ^*1 (i.e., a low turbidity range corresponding to the dry season or winter season) and when the turbidity of the suspension is When the turbidity τ ₀ of the suspension is in a range larger than the predetermined value τ ₀ ^*2 (>τ ₀ ^*1 ) (that is, the high turbidity range corresponding to the typhoon period), and when the turbidity τ ₀ of the suspension is larger than the predetermined value τ 0 *2 (>τ 0 *1 ), ₀ ^*1
and τ ₀ ^*2 (i.e. _, medium turbidity ^range corresponding to the normal period). The data is stored as the latest data. The arithmetic device 136 holds an appropriate number (for example, five) of data regarding the appropriate injection rate W _A1 ^* according to the low turbidity range, medium turbidity range, and high turbidity range. Each time the data on the appropriate injection rate W _A1 ^* is updated, the calculation device 136 uses an appropriate number of data stored for each turbidity range to calculate the injection rate W _A1 of the flocculant. Create a management equation as follows: W _A1 =Aτ ^B (A and B are constants determined by the least squares method). Therefore, the computing device 136 calculates the turbidity τ ₀ given from the turbidity meter 138 or 139 over a period after the data on the appropriate injection rate W _A1 ^* of the coagulant is updated until the next update. The injection rate W _A1 of the flocculant is determined according to the above formula.

140 is a calculation device 136 and a flow meter 142
A multiplier connected to the arithmetic unit 136 and the flocculant injection rate W _A1 outputted by the arithmetic unit 136 and the flowmeter 1
The amount of coagulant to be injected is calculated by multiplying the flow rate of the suspension detected by 42, that is, the amount Q of the suspension supplied to the mixing pond 106.

144 is a flocculant supply device connected to the multiplier 140, which supplies an amount of flocculant to the mixing pond 106 via a supply pipe 146 according to the amount of flocculant to be injected calculated by the multiplier 140. , injecting against a suspension.

(Operation of suspension processing device) Furthermore, with reference to FIG. The operation of the processing device will be explained in detail.

The appropriate injection rate determining device 130 collects the suspension from the landing well 102 via the pump 134 and the supply pipe 132, and determines the appropriate injection rate of the coagulant as described below.
Determine W _A1 ^* .

The turbidity meter 138 attached to the supply pipe 132 or another turbidity meter 139 attached to the supply pipe 108 calculates the turbidity τ of the suspension when the appropriate injection rate W _A1 ^* of the flocculant is determined. The measured turbidity is outputted to the calculation device 136 as turbidity τ ₀ . Incidentally, one of the turbidimeters 138 and 139 may be removed if desired. Both the appropriate injection rate W _A1 ^* of the flocculant and the turbidity τ ₀ of the suspension are given to the calculation device 136.

In the calculation device 136, the turbidity τ ₀ of the suspension is compared with predetermined values τ ₀ ^*1 and τ ₀ ^*2 , and the turbidity τ ₀ is in the low turbidity range,
It is determined which of the medium turbidity range and high turbidity range it belongs to. As a result of this judgment,
The calculation device 136 calculates the appropriate injection rate of the suspension within the turbidity range (i.e., low turbidity range, medium turbidity range, or high turbidity range) to which the turbidity τ ₀ of the suspension belongs. W _A1 ^* is stored instead of its oldest data and updated to the latest data.

The computing device 136 further stores stored data (i.e., a plurality of appropriate injection rates) including the latest data in the updated turbidity range (e.g., medium turbidity range).
Coefficients A and B in the injection management formula W _A1 =Aτ ^B are determined by the least squares method using W _A1 ^* and its determination time τ ₀ ), and are stored in place of the previous injection management formula.

The calculation device 136 is the appropriate injection rate detection device 130
turbidity meter 138 or turbidity meter 139 until a new appropriate injection rate W _A1 ^* is detected by
_Every time _{the turbidity τ 0 of the suspension is input from} Calculate and output as ₀ ^B ₀ .

Injection rate of flocculant output from calculation device 136
W _A1 is multiplied by the flow rate Q detected by the flow meter 142 in a multiplier 140, and is set as the injection amount R ^* of the flocculant.

Depending on the injection amount R ^* of the flocculant, the flocculant is supplied from the flocculant supply device 144 to the mixing basin 106 and injected into the suspension.

According to the flocculant injection management method according to the present invention, by intermittently repeating the above operations,
The flocculant injection rate W _A1 in the suspension processing apparatus shown in Figure 1 can be maintained at a substantially appropriate injection rate W _A1 ^* , which in turn shortens the suspension processing time and eliminates the need for flocculant. injection can be avoided.

Furthermore, to explain with specific numerical values, when the turbidity τ of the suspension changes as shown in FIG. 7a, according to the flocculant injection control method according to the present invention, the flocculant injection rate W _A1 can be controlled more appropriately than in the comparative example according to changes in the turbidity τ of the suspension as shown in FIG. The degree τ can be improved compared to the comparative example as shown in FIG. 7c.

(Configuration of Appropriate Injection Rate Determination Device 130) Furthermore, the configuration of the above-mentioned appropriate injection rate determination device 130 will be explained in more detail with reference to FIGS. 2 to 6.

Reference numeral 10 denotes a batch-type stirring tank, which has an appropriate capacity (for example, a capacity of 1), and contains a mixed liquid 11 of a suspension and a flocculant.

Reference numeral 12 denotes a stirring blade disposed in the stirring tank 10, which is appropriately attached to the free end of an output shaft 16 of a drive means (for example, an electric motor) 14 arranged below the stirring tank 10. .

18 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 10, and is a fluorescent lamp, a tungsten lamp, a halogen lamp, a light emitting diode, etc. , the light generated by a suitable light source such as a laser emitting means is passed through a suitable optical system (for example, a slit).
The light is supplied to the mixed liquid 11 in the stirring tank 10 as a parallel beam of light.

Reference numeral 20 denotes a light receiving device which includes an appropriate photoelectric conversion element such as a phototransistor, photodiode, CdS, or CCD as a light receiving means, and is disposed on the side of the stirring tank 10. The light supplied as a bundle of parallel rays is transferred to the mixed liquid 11.
Light is received through the The light receiving device 20 receives scattered light or attenuated transmitted light because the light given by the light emitting device 18 is scattered or blocked by the aggregates (i.e., flocs) 17 in the liquid mixture 11. There is. The light receiving device 20 may be placed opposite the light emitting device 18 in order to receive transmitted light, or may be placed at a predetermined angle with respect to the parallel light beam from the light emitting device 18 in order to receive scattered light. Good too. In addition, two light receiving devices 20 may be arranged to receive transmitted light and scattered light. To simplify the explanation, it will be assumed below that the light receiving device 20 is opposed to the light emitting device 18. In addition, in FIG. 2, only one set of the light emitting device 18 and the light receiving device 20 is arranged, but
The present invention is not limited to this, and a plurality of sets of light emitting devices 18 and light receiving devices 20 may be arranged. In particular, it is convenient for the light emitting device 18 and the light receiving device 20 to measure the sedimentation state of the aggregate (ie, floc) 17 if they are arranged on the same horizontal plane.

Reference numeral 22 denotes a measuring device connected to the light receiving device 20 via a lead wire 21, and measures the amount of light I received by the light receiving device 20 (hereinafter referred to as "light receiving amount"). In addition, the measuring device 22 calculates, from the measured amount of received light I, the amount of received light I ₁ (τ) before the injection of the flocculant and the fluctuation range of the amount of received light I when flattened due to slow stirring by the stirring blades 12. (That is, the difference between the predetermined values I _L and I _H ) ΔI and the fluctuation period F are determined and output. If desired, the measuring device 22 further measures the amount of received light I _f (τ) when flattening after the slow stirring by the stirring blade 12 has stopped, and the amount of received light I since the time when the slow stirring by the stirring blade 12 has stopped. The time T until flattening may be calculated and output.

24 has one end connected to the stirring tank 1 via the on-off valve 25.
It is a supply pipe that is opened at 0, and the other end thereof is communicated with a supply pipe 132 (see FIG. 1).

A flocculant supply pipe 26 has one end communicating with the flocculant supply source 28 , and the other end thereof is opened to the stirring tank 10 via an on-off valve 27 .

30 is a drain pipe, one end of which is connected to the stirring tank 10.
The stirring tank 10
The detected mixed liquid 11 is removed from the mixture (see FIG. 1).

34 is a dark box, which contains at least the stirring tank 1.
0, houses a light emitting device 18 and a light receiving device 20, and eliminates the influence of external light.

36 is a calculation device connected to the driving means 14, the measuring device 22, and the on-off valves 25, 27, and the peripheral speed ν of the stirring blade 12 is given from the driving means 14, and the amount of received light is calculated from the measuring device 22. I _i (τ), the fluctuation width ΔI and the fluctuation period F of the received light amount I are given, and if desired, the received light amount I _f (τ) and the time T are also given, and the on-off valves 25 and 27 A feed rate M of suspension and a feed rate N of flocculant are given. The arithmetic unit 36 calculates parameters for determining the aggregation state of the aggregates (ie, flocs) 17. That is, the arithmetic unit 36
is the diameter d of the aggregate (i.e. floc) 17 using the constant α and the fluctuation range ΔI (volts) of the amount of received light I.
(cm) is calculated as d=αΔI, and the number of aggregates (i.e., flocs) 17 is calculated using the fluctuation period F (seconds) of the amount of received light I, the circumferential speed ν (m/second) of the stirring blade 12, and the constant β. n (1/cm ³ )
is calculated as n=β(1/Fν) ³ , and the diameter of the aggregate (i.e., floc) 17 is calculated using the diameter d (cm) and n (1/cm ³ ) of the aggregate (i.e., floc) 17 and the constant ε. The volume V (cm ³ ) is calculated as V=εd ³ n , and the initial concentration of suspended solids in the suspension W _SS (mg/) determined from the received light intensity I _i (τ) (volts) and the supply amount M, N Coagulant injection rate W _A1 (mg/) determined from
and the number of aggregates (i.e. flocs) 17 n(1/
cm ³ ), the diameter d, the constant γ, and the coefficient a specific to the flocculant to calculate the effective density ρ (g/cm ³ ) of the aggregate (i.e. floc) 17: ρ=γ1/d ³ n(W _SS +aW _A1 ), and if desired, the aggregate (i.e., floc) 1 can be calculated using the time T and the constant δ.
The sedimentation speed S (cm/min) of No. 7 is calculated as S = δ1/T, and the supernatant water turbidity after sedimentation of aggregate (i.e., floc) 17 is calculated using the received light intensity I _f (τ) and constant λ. τ (degrees) is calculated as τ=λI _f (τ). Here, the parameters calculated by the arithmetic unit 36 and the aggregates (i.e., flocs) 17
The relationship between the actual flocculation state and the diameter d or number n, the volume V, the effective density ρ, the sedimentation velocity S, and the supernatant water turbidity τ is closely related to the actual flocculation state. If it is desired to precisely detect the aggregation state, the latter parameter may be used, and if it is desired to detect the aggregation state even more precisely, a combination of a plurality of parameters may be used.

38 is another calculation device connected to the calculation device 36, which calculates the diameter d, number n, volume V, effective density ρ, and sedimentation velocity of the aggregate (i.e., floc) 17 calculated by the calculation device 36. At least one of the supernatant water turbidity τ after sedimentation of the flocculant S and floc 17 is stored in sequence for the flocculant injection rate W _A1 at that time, and the suspension at this time is The appropriate value of the flocculant injection rate W _A1 with respect to the liquid (that is, the appropriate flocculant injection rate) W _A1 ^* is determined. That is, the arithmetic device 38 operates the on-off valve 25,
The diameter of the aggregates (i.e., flocs) 17 is calculated with respect to the change in the flocculant injection rate W _A1 calculated by the calculation device 36 using the suspension supply amount M and the flocculant supply amount N given from 27. d, the injection rate of the coagulant, corresponding to when the change in the volume V or effective density ρ starts to become steep, and when the change in the number n, sedimentation rate S, or supernatant water turbidity τ starts to become slow.
W _A1 is determined as the appropriate injection rate W _A1 ^* .

(Operation of appropriate injection rate determining device 130) In addition, the operation of the above-mentioned appropriate injection rate determining device 130 will be explained in more detail with reference to FIGS. 2 to 5.

The on-off valve 32 connects to the stirring tank 10 via the drain pipe 30.
It is temporarily opened to remove the mixed liquid 11 remaining inside.

After the on-off valve 32 is closed, the on-off valve 25 supplies a predetermined amount M (for example, 1) of the suspension to the stirring tank 1 from a suspension supply source (not shown) via the supply pipe 24.
It is opened for a predetermined period of time in order to supply within zero.

When the supply of the suspension into the stirring tank 10 is completed,
At time t ₁ , the stirring blade 12 begins to be rotated rapidly or at a high speed by the driving means (for example, an electric motor) 14 . Prior to the start of rapid rotation of the stirring blade 12, the light emitting device 18 and the light receiving device 2
0 and the measuring device 22 have been started, and the amount of received light transmitted through the suspension in the stirring tank 10 I _i (τ)
is measured and provided to the arithmetic unit 36.

Thereafter, at time _t2 , by opening the on-off valve 27 for a predetermined time, a predetermined amount of flocculant is injected into the stirring tank 10 from the flocculant supply source 28 via the flocculant supply pipe 26. . As the flocculant, known flocculants such as polyaluminum chloride may be used as desired. time t ₂
The amount of light I received up to (that is, the time when the flocculant is supplied) is a constant value I _i (τ) corresponding to the initial concentration W _SS of suspended matter contained in the suspension.
When a predetermined amount N of flocculant is injected at time _t2 , flocculates (i.e., flocs) are formed in the mixed liquid 11.
17 is gradually formed and the mixed liquid 11 is rapidly stirred and moved within the stirring tank 10, so the amount of light received by the light receiving device 20 increases slowly.

At time _t3 , when the stirring blade 12 starts to rotate slowly (that is, rotate at a low speed), aggregates (that is, flocs) 17 are further formed in the mixed liquid 11, and their diameter d increases, and the mixed liquid 11 is slowly stirred and moved in the stirring tank 10, the amount of light received by the light receiving device 20 increases and decreases little by little, but increases as a whole.

When time t ₄ is reached, the aggregates (i.e., flocs) 17 are sufficiently agglomerated in the mixed liquid 11 so that the diameter d does not change, and the mixed liquid 11 is in the stirring tank 1.
0, the amount of light I received by the light receiving device 20 becomes flat, and as the aggregate (i.e., floc) 17 passes, it reaches the predetermined values I _L and I _H.
It will fluctuate periodically between

Furthermore, at time _t5 , when the rotation of the stirring blade 12 is stopped to stop stirring, the aggregates (i.e., flocs) 17 formed in the mixed liquid 11 start to settle, so that the amount of light received by the light receiving device 20 decreases. I increases and decreases little by little and reaches a substantially constant value I _f (τ) at time t ₆ .

After time _t6 , the aggregates (ie, flocs) 17 in the liquid mixture 11 no longer settle, so the amount of received light I maintains a constant value I _f (τ).

For example, when using a kaolin suspension prepared by adding 25 mg of kaolin to fresh water in step 1, and injecting polyaluminum chloride at an injection rate of 15 mg/ml, the measurement was performed using the measuring device 22.
The amount of received light I at 0 was as shown in FIG.

Thereafter, the arithmetic unit 36 calculates the diameter d of the aggregate (i.e., floc) 17, as described above.
The number n, volume V, and effective density ρ are calculated, and if desired, the sedimentation rate S and supernatant water turbidity τ are also calculated. Based on these parameters calculated by the arithmetic unit 36, the agglomeration state of the aggregates (ie, flocs) 17 can be detected as described above.

The diameter d, number n, volume V, effective density ρ, sedimentation rate S, and supernatant water turbidity τ of the flocs 17 calculated by the calculation device 36 are determined by the calculation device 38 at the injection rate of the flocculant. Stored for W _A1 . The calculation unit 38 calculates the diameter d, volume V or effective density ρ of the aggregate (ie, floc) 17.
The injection rate of flocculant when the change in starts to become steep
The flocculant injection rate W _A1 when changes in W A1 , or _the number n, sedimentation rate S or supernatant water turbidity τ start to slow down, is determined as the appropriate injection rate W _A1 ^* ,
Output as desired.

The basis for this will be explained in more detail. That is, each time the above measurements and calculations are repeated using, for example, a kaolin suspension prepared by adding 25 mg of kaolin to 1 part of fresh water, the diameter d, number n, volume V, and When the effective density ρ was calculated and blotted against the flocculant injection rate W _A1 , the result shown in FIG. 4 was obtained.

Similarly, using the kaolin suspension, the effective density ρ, sedimentation rate S, and supernatant water turbidity τ of the aggregates (i.e., flocs) 17 are calculated each time the above-mentioned measurements and calculations are repeated. Agent injection rate
When plotted against W _A1 , Figure 5 was obtained.

As is clear from FIGS. 4 and 5, as the flocculant injection rate W _A1 changes, the diameter d, number n, volume V, effective density ρ, and sedimentation velocity of the flocs 17 S and supernatant water turbidity τ are changing. To be more specific, when the coagulant injection rate W _A1 exceeds a predetermined value W _A1 ^* (here 30 mg/),
Although the number n of aggregates (i.e., flocs) 17 does not change much, their diameter d and volume V become relatively large, the effective density ρ decreases, and unstable aggregates (i.e., flocs) 17 are formed. It can be determined that this has been done. In addition, the injection rate of flocculant
When W _A1 exceeds the predetermined value W _A1 ^* , the settling velocity S of the aggregates (ie, flocs) 17 or the supernatant water turbidity τ after the aggregates (ie, flocs) 17 have settled do not change much. Furthermore, even if the coagulant injection rate W _A1 exceeds the predetermined value W _A1 ^* ,
It can be judged that the amount of coagulation and sedimentation of the aggregates (ie, flocs) 17 cannot be increased compared to the increase in the injection amount of the flocculant, which is not preferable.

On the other hand, the flocculant injection rate W _A1 is at its predetermined value.
When W _A1 ^* becomes significantly smaller, the number n of aggregates (i.e. flocs) 17 becomes extremely large;
The diameter d and volume V are also extremely small, and the effective density ρ is increased, and it can be judged that a relatively stable aggregate (ie, floc) 17 is formed. However, at this time, the settling velocity S of the aggregates (ie, flocs) 17 is small, and the supernatant water turbidity τ after the aggregates (ie, flocs) 17 settle is large. Furthermore, if the flocculant injection rate W _A1 becomes significantly smaller than its predetermined value W _A1 ^* , even if the amount of flocculant injection can be reduced, the flocs (i.e., flocs) 17 cannot be efficiently precipitated and removed. It can be determined that this is not desirable.

Therefore, if the predetermined value W _A1 ^* 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. Therefore, suspended matter in the suspension can be efficiently coagulated and precipitated to be removed.

For this purpose, the arithmetic unit 38 determines the predetermined value W _A1 ^* as the appropriate injection rate of the flocculant, as described above.

As described above, in the flocculant injection management method according to the present invention, the flocculant injection rate with respect to the suspension is managed so as to be an appropriate injection rate.

(Modification) In the above description, the appropriate injection rate determination device 130 including only one stirring tank 10 has been described (see FIGS. 2 to 5), but this requires a large amount of effort to detect the agglomeration state. Since this requires time, in the present invention, multiple (four in this case) as shown in FIG.
Two stirring tanks may be placed side by side.

The appropriate injection rate determination device 130 in FIG. 6 has the same structure and operation as the third one, except that the suspension supply source (i.e., supply pipe 132, flocculant supply source 28, and calculation device) 38 is common. Since it is substantially the same as the appropriate injection rate determining device 130 of FIG. 2, each member is given the same reference number as the appropriate injection rate determining device 130 of FIG.
A detailed explanation thereof will be omitted. The letters A, B, C, and D are added to the reference numbers to distinguish between the juxtaposed stirring vessels. Opening/closing valve 27A, ~, 27
D are open for different times, and the mixed liquids 11A, 11A, 10D in the stirring tanks 10A, 10D,
The injection rate of flocculant to 11D is adjusted.

In addition, in the above, the turbidity meters 138, 139
Although the present invention has been described only in the case where the appropriate injection rate determination device 130 determines the appropriate injection rate of the flocculant less frequently than the frequency of turbidity detection by
The present invention is not limited to this case, and if desired, the frequency of turbidity detection by the turbidimeters 139, 139 and the frequency of determination of the appropriate injection rate of the coagulant by the appropriate injection rate determination device 130 may be made to match.

(3) Effects of the invention As is clear from the above, the flocculant injection control method according to the present invention has the following advantages: (a) the first step of collecting the suspension;
(b) a second step of detecting the turbidity of the suspension; (c) determining the appropriate injection rate of the coagulant for the collected suspension; the turbidity is detected in the second step; a third step in which turbidity is detected intermittently depending on the time and at a frequency less than or equal to the frequency at which turbidity is detected in the second step; and (d) in the turbidity range to which the turbidity detected in the second step belongs. (e) a fourth step of storing the appropriate injection rate detected in the third step in place of the oldest stored value in the turbidity range;
Injection management using the appropriate injection rate stored in the fourth process and the turbidity detected in the second process when the appropriate injection rate stored in the fourth process was determined in the third process. (f) a fifth step of creating a formula and storing it in place of the previous injection control formula; and (f) a step of calculating the injection rate of the flocculant using the injection management formula according to the turbidity detected in the second step. (i) Testing This method has the effect of eliminating human visual observation and experience; (ii) it also has the effect of updating the injection control formula for each turbidity range; and (iii) it allows the injection rate of flocculant to be adjusted according to the latest detection results. It also has the effect of optimizing the injection amount.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an actual suspension processing apparatus in which injection of a flocculant is controlled by an embodiment of the flocculant injection management method according to the present invention, and FIG. To show an appropriate injection rate determination device that is included in the suspension processing apparatus shown in the figure and that determines an appropriate injection rate of a flocculant in order to carry out an embodiment of the flocculant injection management method according to the present invention. 3 is an operation explanatory diagram for explaining the operation of the appropriate injection rate determining device shown in FIG. 2, and FIG. 4 is an explanatory diagram of the operation shown in FIG. d, number n, volume V, effective density ρ, and injection rate of flocculant
Figure 5 is a graph to show the relationship between _W 6 is a graph diagram showing the relationship between the injection rate W _A1 and FIG. Figures a to c are graphs showing the results of flocculant injection management according to an embodiment of the present invention in the suspension processing apparatus shown in Figure 1. 102...Water landing well, 106...Mixing pond, 112
... Aggregate formation pond, 118 ... Sedimentation pond, 120...
...filtration pond, 130...appropriate injection rate determining device, 13
6...Arithmetic device, 138,139...Turbidity meter, 1
40... Multiplier, 142... Flowmeter, 144...
Coagulant supply device, 10... Stirring tank, 11... Mixed liquid, 12... Stirring blade, 14... Drive means, 16
... Output shaft, 18 ... Light emitting device, 20 ... Light receiving device, 22 ... Measuring device, 24 ... Supply pipe, 25,
27... Opening/closing valve, 26... Coagulant supply pipe, 28...
...Flocculant supply source, 30...Drain pipe, 32...Opening/closing valve, 34...Dark box, 36, 38...Arithmetic device.

Claims (1)

[Claims] 1 (a) a first step of collecting the suspension; (b) a second step of detecting the turbidity of the suspension; and (c) a step of collecting the suspension in the first step. A second step in which the appropriate injection rate of the flocculant to the suspension is determined intermittently depending on when turbidity is detected in the second step and at a frequency less than or equal to the frequency at which turbidity is detected in the second step. (d) storing the appropriate injection rate determined in the third step in place of the oldest stored value in the turbidity range according to the turbidity range to which the turbidity detected in the second step belongs; (e) detection in the second step when the appropriate injection rate stored in the fourth step and the appropriate injection rate stored in the fourth step are determined in the third step; a fifth step of creating an injection management formula using the detected turbidity and storing it in place of the previous injection management formula; (f) creating the injection management formula according to the turbidity detected in the second step; (g) a seventh step of injecting the flocculant into the suspension to be treated according to the injection rate calculated in the sixth step; A method for managing injection of a coagulant, comprising: 2 The third step consists of (a) a first partial step in which the collected suspension is stirred, and (b) a second partial step in which a flocculant is injected into the suspension being stirred.
(c) a third sub-step of stirring the suspension-flocculant mixture at a lower stirring speed than in the first sub-step after the injection of the flocculant; and (d) a fourth partial step of measuring the amount of received light given from the light emitting device to the light receiving device via the mixed liquid in at least the third partial step; (e) from the amount of received light measured in the fourth partial step; (f) a sixth partial step of determining an appropriate injection rate of the flocculant according to the state of aggregation detected in the fifth partial step; A method for managing injection of a flocculant according to claim 1, characterized in that: 3 (i) In the fifth partial step, detect the aggregation state of the mixed liquid by calculating the number of aggregates from the fluctuation period when the amount of received light is flattened and the stirring speed in the third partial step, and (ii) in the sixth partial 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. Method for controlling the injection of flocculant described in Section 1. 4 (i) In the fifth partial step, the aggregation state of the mixed liquid is detected by calculating the diameter of the aggregate from the fluctuation range when the amount of received light is flattened, and (ii) In the sixth partial step The flocculant according to claim 2 or 3, wherein the injection rate of the flocculant corresponding to when the change in the diameter of the aggregate starts to become steep is determined as the appropriate injection rate. injection management method. 5 (i) In the fifth partial step, calculate the number of aggregates from the fluctuation period when the amount of received light is flattened and the stirring speed in the third partial step, and calculate the fluctuation range when the amount of received light is flattened. (ii) detecting the agglomeration state of the liquid mixture by calculating the diameter of the aggregates from the number of aggregates and calculating the volume of the aggregates from the number and diameter of the aggregates; Claim 2, characterized in that the injection rate of the flocculant corresponding to when the change in the number of aggregates starts to slow down and the changes in diameter and volume start to become steep is determined as the appropriate injection rate. How to manage the injection of flocculant. 6 (i) In the fifth partial step, calculate the number of aggregates from the period of fluctuation when the amount of received light is flattened and the stirring speed in the third partial step, and calculate the width of fluctuation when the amount of received light is flattened. The aggregation state of the mixed liquid 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 matter concentration of the suspension, and the injection rate of the flocculant. (ii) In the sixth partial 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. A method for managing injection of a flocculant according to claim 2, characterized in that: 7 The third step consists of (a) a first partial step in which the collected suspension is stirred, and (b) a second substep in which a flocculant is injected into the suspension being stirred.
(c) a third sub-step of stirring the suspension-flocculant mixture at a lower stirring speed than in the first sub-step after the injection of the flocculant; and (d) a fourth partial step of measuring the amount of received light given from the light emitting device to the light receiving device via the mixed liquid in at least the third partial step; (e) the amount of received light measured in the fourth partial step is flat; a fifth step of stopping stirring of the mixed solution after
(f) a sixth partial step of measuring the amount of received light given from the light emitting device to the light receiving device via the mixed liquid during the fifth partial step; (g) a fourth partial step; a seventh partial step of detecting the agglomeration state of the liquid mixture from the amount of light received in the sixth partial step; (h) appropriate injection of the flocculant according to the aggregation state detected in the seventh partial step; 2. A method for managing the injection of a flocculant according to claim 1, further comprising an eighth partial step of determining the coagulant rate. 8 (i) In the seventh partial step, the turbidity of the supernatant water after the aggregates have been precipitated is calculated from the amount of light received when the amount of received light measured in the sixth partial step is flattened. The flocculation state of the liquid is detected, and (ii) in the eighth partial 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. A method for managing injection of a flocculant according to claim 7. 9 (i) In the seventh partial step, calculate the sedimentation rate of the aggregate from the time from the time when stirring is stopped in the fifth partial step until the amount of received light measured in the sixth partial step becomes flat. (ii) In the eighth partial 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 managing injection of a flocculant according to claim 7, characterized in that: 10 (i) In the seventh partial step, by calculating the number of aggregates from the fluctuation period when the amount of received light measured in the fourth partial step is flattened and the stirring speed in the third partial step, detecting the aggregation state of the liquid mixture, 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 eighth partial step as the appropriate injection rate; A method for managing injection of a flocculant according to any one of claims 7 to 9. 11 (i) In the seventh partial step, by calculating the diameter of the aggregate from the fluctuation width when the amount of received light measured in the fourth partial step is flattened,
detecting the aggregation state of the mixed liquid, and (ii) determining 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 in the eighth partial step; A method for managing injection of a flocculant according to any one of claims 7 to 10. 12 (i) In the seventh partial step, calculate the number of aggregates from the fluctuation period when the amount of received light measured in the fourth partial step is flattened and the stirring speed in the third partial step, and By calculating the diameter of the aggregates from the variation width when the amount of received light measured in sub-step 4 is flattened, and by calculating the volume of the aggregates from the number and diameter of the aggregates, the amount of the mixed liquid is calculated. The flocculation state is detected, and (ii) in the eighth partial 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 volume starts to become steep is determined as an appropriate injection rate. 8. A flocculant injection management method according to claim 7, characterized in that: 13 (i) In the seventh partial step, calculate the number of aggregates from the fluctuation period when the amount of received light measured in the fourth partial step becomes flat and the stirring speed in the third partial step, and Calculate the diameter of the aggregate from the variation width when the amount of received light measured in substep 4 is flattened, and calculate the number and diameter of the aggregate, the suspended matter concentration of the suspension, and the injection rate of the flocculant. (ii) In the eighth partial step, the number of aggregates starts to change slowly and the diameter and effective density change. 8. A flocculant injection management method according to claim 7, characterized in that the flocculant injection rate corresponding to when the slope starts to become steep is determined as the appropriate injection rate.