WO2006067873A1 - Method of measuring and managing sedimentation separation operation and apparatus therefor - Google Patents

Abstract

[PROBLEMS] To provide a method and apparatus for measuring and managing operating conditions in sedimentation operation. [MEANS FOR SOLVING PROBLEMS] A stationary sedimentation container is charged with a set amount of solid/liquid mixture prior to entry in a sedimentation tank. After allowing the mixture to stand still for a set period of time, liquid drainage is carried out while maintaining a relative position of sludge interface level and liquid surface level of the stationary sedimentation container. The SS or turbidity of effluent and drainage elapsed-time during drainage are measured by the use of SS or turbidity measuring means fitted to drainage line. The time for passage of sedimented sludge interface is detected from the measurement values, and the volume of sedimented sludge is computed. Simultaneously, the turbidity of supernatant liquid phase is measured from the measurement values after passage of sedimented sludge interface.

Description

 Specification

 Precipitation separation operation measurement management method and apparatus

 Technical field

 [0001] The present invention relates to a measurement management method and apparatus in a water treatment system that precipitates and separates turbidity or suspended solids (hereinafter referred to as SS) in raw water.

 Background art

 [0002] Conventionally, the following (1) and (2) are generally used for the treatment of wastewater containing turbidity or SS. In other words, (1) coagulation sedimentation treatment that adds acid, alkali, flocculant, etc. to the wastewater, flocks turbidity or SS in the wastewater, leads to the sedimentation tank, and precipitates and separates solids. (2) Activated sludge treatment in which turbidity or SS is decomposed by microbial activity by aeration in an aeration tank, or adhering to and adsorbed on activated sludge, and then guided to a sedimentation tank and precipitated and separated together with activated sludge. When only the turbidity in the wastewater needs to be removed, a coagulation sedimentation process which is easy to operate and can be processed in a short time is widely used.

 [0003] For the flocculation treatment of waste water, inorganic flocculants and polymer flocculants such as salt-aluminum, polysalt-aluminum, aluminum sulfate, ferric chloride, and ferric sulfate are used. The turbidity of raw water is flocculated with these flocculants, introduced into a sedimentation tank, and solid-liquid separated by the difference in specific gravity. The quality of flocculation depends on various factors such as the quality and amount of flocculating agent, the concentration and nature of turbidity in raw water, and the characteristics of the flocculation reaction precipitation apparatus. Even after specifying the equipment and flocculant, the quality of flocculation varies greatly if there are fluctuations in the properties of the raw water. For this reason, in order to properly manage the coagulation sedimentation operation, it is necessary to adjust the amount of coagulant added based on the measured values of the V, R, and R measurement instruments. The measuring instruments used in the coagulation sedimentation process include raw water flow meters, raw water turbidity meters and other water quality measuring instruments such as pH and conductivity, flocculant addition flow meters, and turbidity of the supernatant of the sedimentation tank. There are an accelerometer, an interferometer for the sedimentation sludge in the sedimentation tank, an extracted sludge for the sludge and an SS concentration meter for the coagulated mixture. Even in activated sludge treatment, there are problems such as poor precipitation due to filamentous fungi, and operation management of the solid-liquid separation operation in the sedimentation tank is important, and the same instrument is used.

[0004] Based on the data measured by these instruments, the operation of the precipitation operation is performed so as to achieve an appropriate operating state. Manage the situation. In the case of coagulation sedimentation treatment, the amount of coagulant added and the amount of treatment are adjusted.In the case of activated sludge treatment, the amount of treatment, the amount of returned sludge and the aeration conditions are adjusted. It is not easy to make proper adjustments. The reason for this is that with current measuring instruments, for example, it takes several hours for coagulation sedimentation treatment and more than half a day for only the sedimentation tank for activated sludge treatment, until the fluctuation of raw water appears in the turbidity change of the sedimentation supernatant water. This is because there is a response delay of more than one day from fluctuations in raw water. The difficulty is apparent from the fact that there are various proposals for automatic control of the amount of flocculant added, even though it is simpler than activated sludge treatment and can be processed in a shorter time. As a typical control method, with regard to feedback control that controls the amount of flocculant added by measuring the turbidity of the sedimentation tank treatment water, the turbidity of the actual sedimentation tank treatment water is measured and the response delay in the device is delayed. A method for controlling the amount of flocculant added by correcting the above with a converter is disclosed (for example, Patent Documents).

1). In addition, the feedforward is used to measure the flow rate, turbidity, and other characteristic values of raw water, and to control the amount of flocculant added using a relational expression that obtains the relationship between the estimated turbidity load and the amount of flocculant injected. There is also a proposal regarding control (for example, see Patent Document 2).

[0005] However, in feedback control, there is a response delay of several hours before the fluctuation of raw water clearly affects the treated water from the settling tank, and it is necessary to correct the response delay of the control value. In the case of large raw water, it is difficult to calculate an appropriate control value. In feed-forward control, ambiguity due to response delay can be avoided, but there is a problem that the cost of measuring instruments is high. In addition to factors such as pH and salt concentration that only affect the turbidity of the raw water, there are other factors that cannot be easily explained such as the behavior of colloids. There is also the problem that it is difficult to catch.

[0006] Thus, with the current technology, any method is insufficient to accurately grasp the behavior of precipitation. In order to accurately capture the behavior of agglomeration and reflect it in operation, it is possible to reduce the ambiguity due to response delay in feed knock control and to accurately grasp the agglutination factor in feed forward control. Appropriate measurement control instruments are required. In activated sludge treatment, as shown by the fact that countermeasures against poor sedimentation by filamentous fungi have become a problem, the response is large, which makes it more difficult to clarify the phenomenon and take countermeasures. The However, if the early detection of the phenomenon and the confirmation of the treatment effect can be performed appropriately, the phenomenon of sedimentation failure will be solved. Therefore, there is a particularly high demand for a device that can appropriately measure and manage the precipitation operation.

 Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-8901

 Patent Document 2: JP 2002-66209 A

 Disclosure of the invention

 Problems to be solved by the invention

[0007] The present invention measures and manages the operating state in the precipitation operation. In the coagulation precipitation process, the least! /, The best treated water turbidity with the added amount of coagulant, and the minimum sludge compaction state with the minimum An object of the present invention is to provide a measurement management method and apparatus that makes it possible to realize a ludge volume and to clarify sedimentation failure in a sedimentation tank in activated sludge treatment.

 Means for solving the problem

[0008] The gist of the present invention is as follows. That is, the precipitation separation operation measurement management method according to the present invention is:

 In a water treatment system that settles and separates turbidity or suspended solids by leaving waste water containing suspended or suspended solids (hereinafter referred to as raw water), the solid-liquid mixture before entering the sedimentation tank A first step of charging a set amount to the settling container, a second step of discharging the liquid while maintaining the relative position between the liquid level and the sludge interface level of the settling container after standing for a set time, and discharging The third step of measuring the elapsed discharge time and the suspended solids or turbidity of the discharged liquid, and at least the time that the precipitated sludge interface passes is detected from the measured value, and the discharge speed of the discharged liquid and the precipitated sludge are detected. A fourth step of calculating the sludge volume of the precipitated sludge from the time that the interface passes, and a fifth step of measuring the turbidity of the supernatant liquid phase from the measured value after the precipitate sludge interface has passed. (Claim 1).

 [0009] In the above case, when the raw water enters the sedimentation tank, a flocculant or the like is added to flocculate turbidity or suspended solids or a treatment such as aeration. In addition to the step, the method includes a step of charging raw water in a stationary sedimentation vessel and a step of measuring suspended solids or turbidity of the raw water (Claim 2).

[0010] Further, in addition to the first step, the supernatant water of the sedimentation tank is charged into the stationary sedimentation container. And measuring the suspended solids or turbidity of the supernatant water.

(Claim 3).

 [0011] In the third step, whether the sedimentation sludge phase is consolidated or not is judged from the degree of variation in the measured value of suspended solids or turbidity when the sedimentation sludge phase passes through. (Claim 4).

 In addition, in the third step, the liquid discharge is determined based on the change in the measurement amount when the liquid in the cell for measuring suspended solids or turbidity is filled and the change in the measurement amount when the cell runs out of liquid. The method further includes a step of detecting completion of dispensing and measuring a liquid discharge rate (claim 5).

 [0012] The precipitation separation operation measurement management device according to the present invention is a precipitation separation operation measurement management used in a water treatment system for precipitating and separating turbidity or suspended solids by allowing raw water to stand. A means for charging the settling amount of the solid-liquid mixture before entering the settling container, and a means for discharging the liquid while maintaining the relative position between the liquid level and the sludge interface level of the settling container after settling for a set time. And a means to measure the discharge elapsed time during discharge and the suspended solids or turbidity of the discharged liquid, and at least the time required for the precipitation sludge interface to pass from the measured value to detect the discharge speed of the discharged liquid and the precipitated sludge. It is characterized by comprising means for calculating the sludge volume of the precipitated sludge from the time that the interface passes, and means for measuring the turbidity of the supernatant liquid phase after the sediment sludge interface has passed. (Claim 6).

 According to each of the above inventions, the precipitation separation operation can be appropriately managed, and the discharge rate used in the apparatus can be automatically calibrated and verified to improve the reliability of the apparatus.

 [0013] According to the precipitation separation operation measurement and management apparatus of the water treatment system according to the present invention, activated sludge treatment, coagulation precipitation treatment that promotes solid-liquid separation by adding an acid, an alkali agent, and a flocculant, or agglomeration. In flotation treatment, solid-liquid separation devices such as sludge dewatering devices, and other water treatment devices, it is possible to achieve proper operation management and to stabilize the quality of the treated water.

A feature of the present invention is that the sludge volume and the compactness of the precipitated sludge can be measured from the turbidity of the supernatant, the position of the interface and the discharge time with one apparatus. Furthermore, the turbidity of raw water, It is also possible to measure the turbidity of physical water, and to control the amount of flocculant added appropriately based on these measured values. Each of the above measured values can be measured by using a dedicated measuring instrument. If these measured values are measured using a combination of existing instruments, the equipment becomes complicated and expensive, and is not practical. Moreover, it cannot be said that performance is sufficient. For example, as a device for detecting the sludge interface, there is a method of detecting by reflection of light. When a part of coagulated sludge is floating, measurement is impossible. In addition, there is a method of measuring the turbidity of the treated water and the sludge interface while moving the turbidity sensor in the sedimentation tank, but this method has the disadvantage of complicated equipment such as the structure of sensor movement. Also, this method cannot measure the compactness. Another feature of the present invention is that the solid-liquid mixed solution before entering the settling tank is sampled, a short simulated settling tank is provided in the measuring device, and the turbidity of the supernatant is measured and managed. As a result, the changing power of raw water can be measured with a delay of about 20-30 minutes until the instrument senses it. This has the great advantage that the effect of the response delay is much smaller than the feedback control method when measuring the turbidity of the supernatant water of the sedimentation tank.

 In addition, since the information obtained by operations very close to the behavior in the actual sedimentation tank can be measured, the advantage of being able to predict the agglomeration more accurately compared to the feed-forward control method that manages the raw water treatment volume and turbidity. There is.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, description will be made mainly using the coagulation sedimentation treatment as an example. The general form of the coagulation sedimentation device is configured as shown in Fig. 1. The raw water supplied from the raw water pump 1 enters the rapid agitation reactor 2 and is added with polysalt-aluminum (PAC) etc. from the inorganic flocculant addition pump 3 and mixed and reacted with the inorganic flocculant by rapid stirring. Aggregates turbidity components in raw water. The agglomerated mixed solution from the rapid stirring reactor 2 enters the slow stirring reactor 4 and the polymer flocculant is added from the polymer flocculant addition pump 5, and the aggregated solids are greatly grown by slow stirring. . If pH adjustment is necessary in the above process, acid or alkali is added to maintain the pH appropriate for the aggregation reaction. When the agglutination reaction is carried out only with the cationic polymer flocculant, only the rapid agitation reactor 2 may be used. After the coagulation reaction, the mixed solution enters the coagulation sedimentation tank 6 and is separated into coagulated sludge and supernatant. The supernatant is discharged from the settling trough 7 as treated water. On the other hand, the coagulated sludge is discharged from the bottom of the precipitation tank. Inorganic flocculant The polymer flocculant addition pump is driven by the outputs of inverters 8 and 9, respectively. The measurement control device 10 of the present invention starts by sampling a part of the mixed solution before the agglutination reaction is finished and entering the precipitation tank.

 FIG. 2 shows a configuration example of the precipitation separation operation measurement management device of the present invention. The measurement management device 10 includes a stationary sedimentation container 11, a vacuum pump 12 for sucking liquid into the stationary sedimentation container 11, an open-air solenoid valve 13 for discharging liquid, and a discharge flow control solenoid valve 14 A discharge flow control orifice 15, a discharge line 16 at the bottom of the stationary sedimentation vessel 11, a sensor unit 17 of a turbidimeter for measuring SS or turbidity of the liquid passing through the discharge line, and a mixed liquid sample after the agglutination reaction A solenoid valve for sampling 18, a solenoid valve for sampling raw water 19, a solenoid valve for sampling supernatant water 20, and a solenoid valve for drainage 21. The stationary sedimentation container 11 is sealed with a solenoid valve or the like, and a pressure sensor 22 for measuring the pressure in the container is installed. The tip of the solenoid valve 18 is connected to the outlet of the slow stirring reactor 4 so that the mixture after the agglutination reaction can be sampled. Although not shown, the end of the solenoid valve 19 can sample the raw water, and the tip of the supernatant water sampling solenoid valve 20 can sample the treated water in the trough of the settling tank. It is summer. The PC 23 is equipped with a PC card 24, through which digital output, analog-to-digital conversion, digital-to-analog conversion are performed, and the solenoid valve on / off operation, vacuum pump operation operation, turbidimeter 25 The measured value of the pressure sensor 22 is taken into the computer. Furthermore, the control amount from the computer 23 is output to the inverters 8 and 9 of the flocculant addition pump.

 [0016] As the turbidimeter, an optical sludge densitometer based on light transmission or reflection, an ultrasonic densitometer, a microphone mouth wave densitometer, or the like can be used, but the agglutination reaction is intended to clarify the supernatant. In many cases, a densitometer that can measure low turbidity is preferable. In the present embodiment, an optical sludge densitometer using the simplest laser light transmission structure will be described as an example. As a sampling method, a combination of a pump and a level sensor, which is a combination of a vacuum pump, a solenoid valve, and a pressure sensor as in the above example, is also possible! /.

 Next, the operation of the measurement management device 10 will be described.

After washing the stationary sedimentation vessel 11, start from a state where the washing water is discharged. Close all the solenoid valves and seal the stationary sedimentation container 11, then operate the vacuum pump 12 to settle the sedimentation. Depressurize the container 11 with the set pressure P. Next, open the solenoid valve 18 and suck the mixed solution after the coagulation reaction. The pressure in the stationary sedimentation container 11 changes due to suction, but when the pressure reaches P2, the solenoid valve 18 is closed. If there is no temperature change, the suction volume and space volume V0, Pl, and P2 have the relationship of Equation 1, so the measured value of the pressure sensor 22 is taken into the computer and the computer force is also operated by operating the solenoid valve with digital output. Any amount can be aspirated.

 Suction volume = V0 (1— P1ZP2) (1)

After suction, the solenoid valve 13 and the drainage solenoid valve 21 are opened, and the liquid in the stationary sedimentation container 11 is discharged. This operation is repeated as many times as necessary, and the liquid remaining in the pipe from the outlet of the slow stirring reactor 4 to the stationary precipitation vessel 11 is replaced with fresh liquid. Hereinafter, this operation is referred to as a replacement process. Immediately after completion of the replacement process, the vacuum pump 12 is activated and the inside of the stationary precipitation vessel 11 is reduced to the set pressure P, then the solenoid valve 18 is opened, and after the agglutination reaction, the mixed solution is sucked and the stationary precipitation vessel Sample the mixture after the agglomeration reaction of the set amount in 11. When sampling is completed, the solenoid valve 13 is opened, and the inside of the stationary sedimentation container 11 is left at atmospheric pressure for a set time t. By standing, the mixed solution after the agglutination reaction is separated into precipitated sludge and supernatant. The stationary sedimentation container 11 in Fig. 2 shows a state where it is separated into sedimentary sludge and supernatant. After t time has elapsed, solenoid valve 13 is closed, and solenoid valve 14 and drainage solenoid valve 21 are opened. After the agglomeration reaction, the mixed solution is discharged from the drain solenoid valve 21 via the discharge line at a substantially constant low flow rate according to the air resistance of the orifice 15. The liquid level and the sludge interface level of the stationary sedimentation vessel decrease while keeping the relative position as they are discharged. The orifice 15 is set in advance so that the discharge flow rate decreases while maintaining the relative position of the liquid level of the stationary sedimentation vessel and the sludge interface level. There are some differences depending on the shape of the stationary sedimentation vessel and the quality of the coagulated sludge. 1S Generally, the relative position between the liquid level and the sludge interface level can be maintained if the liquid level drop rate is about 15 cm / min or less. . The effluent is measured for transmitted light intensity with a transmitted light turbidimeter 17 set in the discharge line, and changes due to elapsed time are taken into the computer 23. Completion of liquid discharge is judged by analysis of transmitted light intensity or set elapsed time, and solenoid valve 14 and drainage solenoid valve 21 are closed. Analyzing the transmitted light intensity change data captured by the computer 23 as described below, detecting the time that the sludge interface passes through, and determining the sludge volume of the precipitated sludge from the discharge speed of the effluent and the time that the precipitated sludge interface passes through. Calculated and the sludge interface The degree of compaction is judged from the data when the compacted sludge phase passes before the overtime, and the turbidity of the supernatant is measured from the data when the supernatant liquid phase passes after the passing time of the sludge interface.

 [0018] The discharge speed of the discharged liquid is determined by the viscosity of the liquid, the liquid level, the orifice shape, the resistance of the drain pipe, and the like. Since the orifice shape and drain pipe resistance are device characteristics, an approximate setting can be made if the discharge time and discharge amount are measured in advance for each coagulated mixture, raw water, and supernatant. Fig. 16 shows the relationship between the discharge time, discharge flow rate fl, and integrated discharge amount f2. Differences that change from measurement to measurement, such as dirt on the orifice, dirt on the drain pipe, and temperature, and that slightly affect the discharge flow rate can be corrected by the operation corresponding to claim 5. Of course, as a means for discharging the liquid, it may be discharged by a metering pump without using an orifice, or the inside of the container can be pressurized and pushed out by a constant discharge amount air pump.

 [0019] Before the raw water enters the sedimentation tank, a flocculant is added to flocculate suspended solids or a process such as aeration (corresponding to claim 2). After performing the replacement process using the solenoid valve 19, the raw water is sampled and discharged, and the transmitted light turbidimeter 17 measures the transmitted light intensity when passing through the raw water to measure the turbidity.

 [0020] When the operation corresponding to claim 3 is performed, after performing the replacement process using the vacuum pump 12 and the solenoid valve 20, the trough force of the sedimentation tank also samples and discharges the treated water, and transmits the turbidity meter. In 17 measure the transmitted light intensity when passing through the treated water and measure the turbidity.

 [0021] The relationship between the transmitted light intensity Y and the turbidity in the transmitted light turbidimeter is shown in the section G1 in Fig. 3, where Y0 is the transmitted light intensity of the blank liquid with turbidity 0 and Eq. (2) is the absorbance. Thus, turbidity or SS and absorbance are in a low turbidity range and have a linear relationship as shown in equation (3), so turbidity can be accurately measured. A blank solution with a turbidity of 0 has no practical problem as the transmitted light intensity when passing through the wash water. Absorbance = log (Y0 / Y) (2)

 Turbidity = Coefficient X Absorbance (3)

[0022] After the series of operations described above, although not shown, it is preferable to suck the washing water and wash the stationary sedimentation container 11. The operation time is approximately 15 minutes for the mixed solution after the agglutination reaction, 5 minutes for the raw water turbidity measurement, 5 minutes for the treated water turbidity measurement, and 3 minutes for the washing. By repeating this operation, almost 20-minute force can be measured every 30 minutes. The state can be measured, and the amount of flocculant added can be appropriately controlled based on the data.

 In the case of performing claims 2 and 3, the measurement order is preferably the same as the flow of raw water turbidity measurement → measurement of the mixed liquid after agglutination reaction → measurement of treated water turbidity → washing with the flow of the coagulation precipitation operation.

[0023] FIG. 4 is a diagram showing an example of a change in transmitted light intensity in the case of a mixed solution after agglomeration reaction having a good aggregation state. Fig. 5 is a diagram showing the separation state in the stationary sedimentation container immediately before the discharge. The tl section in Fig. 4 shows the change in transmitted light intensity when the consolidated sedimentary sludge phase passes.

 The t2 section is the change in transmitted light intensity when the sludge interface passes! The t3 interval is the change in transmitted light intensity when the supernatant phase passes. Section t4 is the change in transmitted light intensity when the discharge is completed.

 When passing through the sludge interface, the force that the transmitted light intensity changes rapidly from small to large as in the t2 section can be easily analyzed. For example, if the derivative of the change curve is taken, it will be as shown in Fig. 6 and the peak will be the center of the change, so that point can be determined as the sludge interface passage time ts. By storing the relationship between the discharge time and the discharge amount in advance in the computer, the sludge volume from ts to the sludge interface can be calculated. If SV = 100 X sludge volume Z sampling amount, SV is an important index for judging the coagulation performance. The tl section before ts is the transmitted light intensity when the compacted sludge phase passes. In general, in the transmitted light turbidimeter, the relationship between transmittance and turbidity (SS) exceeds the linear relationship range and falls within the G2 region in Fig. 3, so the SS quantitative accuracy is poor. It is difficult to judge. The t3 section after ts is the transmitted light intensity when the supernatant liquid phase is passing, and the turbidity of the supernatant can be measured from the transmitted light intensity in the stable region of t3 section. Index.

[0024] FIG. 7 is a diagram showing an example of a change in transmitted light intensity when part of the precipitated sludge floats. FIG. 8 is a diagram showing the separation state in the stationary sedimentation container immediately before the discharge at that time. If the derivative of the change curve is taken, as shown in Fig. 9, a positive peak is obtained when the sedimentation sludge passes through the interface. As the sludge passes through the interface of the sludge, it has a negative peak, so the sedimentation sludge interface passage time ts and the sedimentation flotation sludge interface passage time tf can be determined, and the sludge volume can be calculated from the relationship between the discharge time and discharge. The sludge levitation phenomenon is a phenomenon in which fine bubbles attach to sludge and become buoyant. The cause of bubbles and the adhesion to sludge In addition, complicated factors such as device characteristics and raw water properties are involved. The sludge levitation phenomenon greatly affects the sedimentation performance of the sedimentation tank. In activated sludge treatment, if a denitrification reaction occurs in the sedimentation tank, nitrogen gas, etc. is generated, which may cause a serious problem of sludge floating. Therefore, it is significant to be able to measure this phenomenon early. .

 Next, an operation corresponding to claim 4 will be described.

 FIG. 10 is a diagram showing an example of a change in transmitted light intensity in the case of a mixed solution after agglomeration reaction having poor compactness. FIG. 11 is a diagram showing the separation state in the stationary sedimentation container immediately before the discharge at that time. The characteristic of the transmitted light intensity change at this time is that the sludge interface passage time ts is identified by the same analysis as described above, and the transmitted light intensity in the previous tl section is not as smooth as the case of Fig. 4. It is a barracks against the center value. This phenomenon occurs when sludge is poorly consolidated. In other words, in the stationary state, the coagulated sludges are in contact with each other. When the liquid is discharged, the sludge phase is pulled down and separated into small blocks, and the supernatant liquid enters the space (see Fig. 11). ), Because it passes through the sensor part of the turbidimeter. The worse the compactness, the more prominent this phenomenon becomes and the greater the variation. Therefore, the compactness can be evaluated from the size of the variation.

 In such a case, the consolidated sludge swells, so the SV value calculated from the sludge interface passage time ts is slightly larger than the SV value in the stationary state. Since it becomes larger and the evaluation is in the same direction, it does not hinder the judgment.

 FIG. 12 is a diagram showing a specific example in which the compaction is evaluated from the change in transmitted light intensity in the case of a mixed liquid after aggregation reaction having very good compaction. Each point in the figure is a sample of the change in transmitted light intensity every second. The solid line of Θ seconds for the time range during which the sludge phase passes is the simple regression line Y = bl as a result of single regression analysis with the discharge time as the explanatory variable X and the transmitted light intensity value at that time as the target variable Y 'X + bO. The magnitude of the variation can be evaluated by, for example, the error σ per unit time obtained by dividing the squared product sum ε i2 of the square of the residual power ε i of the single regression line by Θ and taking the square root. There is little variation in the precipitated sludge phase of the mixed liquid after the coagulation reaction, which has very good compaction, and σ = 17 in Fig. 12.

FIG. 13 is a diagram showing a specific example in which the compaction is evaluated from a change in transmitted light intensity in the case of the mixed liquid after the aggregation reaction having relatively good compaction. Each point of the figure and the sludge phase pass through The solid line in the box is the same as described above. The variation in Fig. 13 is larger than Fig. 12, σ = 64.

FIG. 14 is a diagram showing a specific example in which the compaction is evaluated from the change in transmitted light intensity in the case of the mixed liquid after the aggregation reaction having poor compaction. Each point in the figure and the solid line in the range through which the sludge phase passes are the same as described above. The variation in Fig. 14 is very large, σ = 160.

FIG. 15 is a graph showing the relationship between the amount of flocculant added to the same raw water, supernatant turbidity, SV, and compactness. In Fig. 15, it is shown as compactness = ΐΖ σ. As shown in the figure, the turbidity of the supernatant decreases as the amount of flocculant added increases, and good treated water can be obtained. However, if it exceeds the appropriate amount, the turbidity will not decrease so much, and the SV will increase and the compactness will deteriorate. In the range exceeding the appropriate amount, the consolidation evaluation according to the present invention has an advantage that the change tends to be larger than the change in SV. In addition, since SV is affected by the raw water turbidity, the amount of coagulant added, and the compactness, when the turbidity of the raw water changes, it is difficult to determine the compactness of the SV change force. When the amount of flocculant added is controlled appropriately, the lack of flocculant can be easily judged from the supernatant turbidity, but when it is excessive, the supernatant turbidity changes little and is difficult to judge. However, if the consolidation evaluation method according to the present invention is used, it can be appropriately evaluated even if there is a fluctuation in raw water. Consolidation is an important indicator in the sedimentation operation as well as the SV value, and is strongly related to sedimentation in the presence of strong flow as in an actual sedimentation tank. In addition, when activated sludge treatment is performed by bulking with filamentous fungi or denitrification occurs in the sedimentation tank, there is a significant decrease in the compactness, and it is highly meaningful to evaluate the compactness.

[0030] Next, an embodiment corresponding to claim 5 will be described. In Fig. 4, the transmitted light intensity L0 when there is no liquid in the cell of the turbidimeter sensor and the air enters the cell gap is from the transmitted light intensity L2 when the supernatant is filled by scattering. descend. Even when there is no sludge floating when the liquid is discharged, the sludge that adheres to and accumulates on the tapered portion of the bottom of the stationary sedimentation vessel is washed and washed by the liquid flow immediately before the liquid discharge ends. The light intensity decreases and the force discharge ends. For this reason, the change in transmitted light intensity before and after the completion of liquid discharge appears as a curve change near the boundary between the t3 and t4 intervals in Fig. 4. Furthermore, as shown in Fig. 6, the differential change can be easily detected because it becomes a positive peak after a negative peak. If there is almost no sludge deposit on the taper part, the peak of the plus becomes small and the force may be almost inconspicuous. Negative peaks remain. The transmitted light intensity L0 when air enters the cell gap can be measured in advance, and by storing it in the computer, the peak is detected by the change in the differential, and then the t3 and t4 intervals in Fig. 4 When the measured value in the vicinity of the boundary becomes constant (almost L0), it can be judged that the discharge is complete.

 [0031] In the measurement described above, the pressure value force of equation (1) is operated, the sample pump is charged with an arbitrary amount by operating the vacuum pump and the solenoid valve, and the discharge time calibration curve is obtained by automatically measuring the liquid discharge time. Easy to create. In addition, by measuring the discharge time of the liquid charged by a certain amount, it is possible to correct the discharge speed by changing the properties of the solid-liquid mixture. Furthermore, it is possible to detect device abnormalities such as clogging.

 [0032] As described above, according to the present invention, the amount of flocculant added can be appropriately controlled. The basis is the use of supernatant turbidity, SV, and sludge phase compaction information obtainable by the methods of claims 1 and 4. In the method of using the turbidity of the supernatant water in the sedimentation tank for control, there is a response delay of 1 to several hours even in coagulation sedimentation. Therefore, it is necessary to compensate for the delay in the control value. Difficult to control. In contrast, the method using supernatant turbidity has a very strong correlation with the supernatant water turbidity in the actual sedimentation tank, and can be measured in about 15 minutes after sampling, resulting in a large response delay error. To decrease. Moreover, by obtaining the turbidity information of raw water using the invention of claim 2, the turbidity information of the supernatant water is calculated, the cohesive strength of SV and the sludge phase, the appropriate amount of flocculant added, and the turbidity information of the raw water In addition, correction can be made in a feed-forward manner. Further, by obtaining the supernatant water turbidity information of the sedimentation tank using the invention of claim 3, it becomes possible to verify the result of the control and the reliability of the control is increased. The measured value of the turbidimeter converter 25 is taken into the computer 23, the control amount is calculated by the computer 23, converted from digital to analog by the PC card, and the control amount is output to the inverters 9 and 10 of the flocculant addition pump Control the amount of flocculant added and generate alarms with a digital output PC card.

 Industrial applicability

[0033] The present invention is not limited to precipitation separation by gravity such as solid-liquid separation in coagulation sedimentation and activated sludge sedimentation, but also for evaluation and optimization of operations in which coagulation action is a key point such as coagulation flotation and sludge dewatering. Is also available. Brief Description of Drawings

FIG. 1 is a view showing a coagulation sedimentation processing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a measuring apparatus according to an embodiment of the present invention.

FIG. 3 is a graph showing the relationship between transmittance and SS or turbidity in a transmitted light densitometer.

FIG. 4 is a diagram showing an example of a change in transmitted light intensity in the case of a mixed solution after agglomeration reaction having a good aggregation state.

 FIG. 5 is a diagram showing a separation state in a stationary sedimentation container immediately before discharge in the case of a mixed solution after agglomeration reaction having a good aggregation state.

 FIG. 6 is a diagram showing a differentiated curve of transmitted light intensity in the case of a mixed solution after agglomeration reaction having a good aggregation state.

 FIG. 7 is a diagram showing an example of a change in transmitted light intensity when part of the precipitated sludge floats.

[Fig. 8] A diagram showing a separation state in a stationary sedimentation container immediately before discharge when a part of the sedimentation sludge has floated.

 [Fig. 9] Differentiated curve of transmitted light intensity when part of the precipitated sludge floats up.

FIG. 10 is a diagram showing an example of changes in transmitted light intensity in the case of a mixed solution after aggregation reaction with poor compaction.

 [Fig. Ll] (a) A diagram showing a separation state in a stationary precipitation vessel immediately before discharge in the case of a mixed solution after agglomeration reaction with poor compaction. (B) It is a figure which shows the behavior of the sludge phase in a stationary sedimentation container at the time of discharge.

 FIG. 12 is a diagram showing a specific example of evaluating the compactness based on the changing power of the transmitted light intensity in the case of the mixed liquid after the aggregation reaction having very good compaction.

 FIG. 13 is a diagram showing a specific example of evaluating the compaction from the change in transmitted light intensity in the case of a mixed liquid after agglomeration reaction having relatively good compaction.

 FIG. 14 is a diagram showing a specific example for evaluating compaction from a change in transmitted light intensity in the case of a mixed liquid after agglomeration reaction with poor compaction.

 FIG. 15 is a graph showing the relationship between the amount of flocculant added and the turbidity, SV, and pressure density of the supernatant.

FIG. 16 is a diagram showing the relationship between the discharge time, discharge speed, and integrated discharge amount of a stationary sediment container. The

Explanation of symbols

 1 Raw water pump

 2 Rapid stirring reactor

 3 Inorganic flocculant addition pump

 4 Slow stirring reactor

 5 Polymer flocculant addition pump

 6 Coagulation sedimentation tank

 7 Settling tank trough

 8, 9 inverter

 10 Measurement management device

 11 Static precipitation container

 12 Vacuum pump

 13 Solenoid valve open to atmosphere

 14 Discharge flow control solenoid valve

 15 Discharge flow control orifice

 16 Out line

 17 Transmitted light turbidimeter

 18 Solenoid valve for sampling liquid mixture after agglomeration reaction

19 Raw water sampling solenoid valve

 20 Solenoid sampling valve

 21 Discharge solenoid valve via discharge line

 22 Pressure sensor

 23 Computer

 24 cards

 5 Turbidimeter converter

Claims

The scope of the claims  [1] In a water treatment system that settles and separates turbidity or suspended solids by standing waste water containing suspended or suspended solids (hereinafter referred to as raw water).  A first step of charging a set amount of the solid-liquid mixture before entering the precipitation tank into a stationary precipitation vessel;  A second step of discharging the liquid while maintaining the relative position between the liquid level of the stationary settling container and the sludge interface level after standing for a set time;  A third step of measuring the elapsed discharge time during discharge and the suspended solids or turbidity of the effluent;  A fourth step of detecting at least the time during which the precipitated sludge interface passes from the measured value, and calculating the sludge volume of the precipitated sludge from the discharge rate of the effluent and the time through which the precipitated sludge interface passes;  A fifth step of measuring the turbidity of the supernatant liquid phase from the measured value after passing through the sedimentary sludge interface;  A method for measuring and managing a precipitate separation operation, comprising:  [2] When raw water enters the sedimentation tank, flocculant or the like is added to flocculate turbidity or suspended solids or treatment such as aeration! The method for controlling and managing a precipitation separation operation according to claim 1, further comprising a step of charging raw water in a stationary sedimentation vessel and a step of measuring suspended solids or turbidity of the raw water. .  [3] In addition to the first step, the method further comprises a step of charging the supernatant water of the sedimentation tank in the stationary sedimentation vessel, and a step of measuring suspended solids or turbidity of the supernatant water. The precipitation separation operation measurement management method according to claim 1.  [4] In the third step, the step of judging whether the sedimentation sludge phase is compact or not based on the magnitude of dispersion of the suspended solids or the measured value of turbidity when the sedimentation sludge phase is passing further. The precipitation separation operation measurement management method according to claim 1, comprising: [5] In the third step, the amount of liquid discharged from the change in the amount measured when the cell that measures suspended solids or turbidity is full and the amount measured when there is no more liquid in the cell. Complete 2. The method for measuring and managing a precipitation separation operation according to claim 1, further comprising a step of detecting the flow rate and measuring a liquid discharge rate. Precipitation separation operation measurement management used in a water treatment system that separates turbid or suspended solids by allowing raw water to stand,  A means for charging the settling amount of the solid-liquid mixture before entering the settling tank, and the liquid level while maintaining the relative position between the liquid level and the sludge interface level of the settling container after settling for a set time. Means for discharging  A means of measuring the elapsed time of discharge during discharge and the suspended solids or turbidity of the effluent,  From the measured value, at least the time that the sedimentation sludge interface passes is detected, and from the discharge rate of the effluent and the time that the sedimentation sludge interface passes, the sludge volume of the sedimentation sludge is calculated and the measurement value after the precipitation sludge interface passes Means for measuring the turbidity of the supernatant liquid phase, and a precipitation separation operation measurement management device comprising: