WO2013008520A1

WO2013008520A1 - Sedimentation evaluation device and optimum addition amount calculation device

Info

Publication number: WO2013008520A1
Application number: PCT/JP2012/062055
Authority: WO
Inventors: 渡邊　洋; 忠幸木曽
Original assignee: 積水アクアシステム株式会社
Priority date: 2011-07-12
Filing date: 2012-05-10
Publication date: 2013-01-17
Also published as: JP5326055B2; JPWO2013008520A1

Abstract

A sedimentation evaluation device comprises: a beaker (4) that contains raw water; a water sampling tube (12) that continuously samples and supplies raw water from the bottom section of the beaker (4); and a fine particle measuring instrument (2) that measures the number of particles in the supplied raw water. An optimum addition amount calculation device: calculates, with each said unit and using a calculation unit (1a), the amount of change in the number of particles in a large particle diameter range and a small particle diameter range during a standing period, the average value for the number of particles in the small particle diameter range during the standing period, and the amount of change in the number of particles in the large particle diameter range after at least one minute has passed during a rapid agitation period; and calculates the optimum addition amount using an optimum addition amount calculation unit (1b) on the basis of the calculation results and the amount added of at least one of either a coagulant or an auxiliary coagulant.

Description

Precipitation evaluation device and optimum addition amount calculation device

The present invention relates to a sedimentation evaluation method and a sedimentation evaluation apparatus for evaluating sedimentation properties of particles in raw water (river water, sewage, used industrial water, etc.) containing particles such as suspended particles. The present invention relates to a sedimentation evaluation apparatus useful for agglutination test). Jar test determines the amount of flocculant added to the raw water before adding the flocculant to the raw water in the coagulation pond to agglomerate and settle the suspended particles contained in the raw water at the water treatment facility Therefore, the flocculant or both the flocculant and the flocculant auxiliary agent are added to the sampled raw water in various addition amounts, and the suspended particles are aggregated and the sedimentation state of the particles in the raw water is good. It is to evaluate whether it is. The present invention also relates to an optimum addition amount calculation device that calculates an optimum addition amount of at least one of a flocculant and a flocculant auxiliary agent to raw water using the sedimentation evaluation apparatus.

In water treatment facilities, there is a demand to remove suspended particles contained in raw water such as river water, sewage, and used industrial water. In general, raw water contains particles of various particle sizes, and among these particles, fine particles (colloid particles) having a particle size of 1 μm or less do not settle and are suspended particles (both suspended solids). Called). For this reason, in water treatment facilities, in general, a coagulant (such as polyaluminum chloride (hereinafter abbreviated as “PAC”)) is added to the raw water in a coagulation pond (also called a rapid mixing pond / particle formation pond). Further, a coagulant aid (for example, sodium carbonate called soda ash, sodium hydroxide called caustic soda, bentonite called a coagulant accelerator, etc.) is added in advance as necessary, so that the suspension contained in the raw water is added. Turbid particles are agglomerated more efficiently (combined with each other) and converted into large particles that are easy to settle. Next, the suspended water is removed by solid-liquid separation by transferring the raw water from the agglomeration pond to the settling basin and allowing the particles to settle.

When the addition amount of the flocculant is less than an appropriate amount, the suspended particles do not sufficiently aggregate, so that the particles cannot sufficiently settle in the sedimentation basin. On the other hand, when the addition amount of the flocculant is larger than an appropriate amount, in addition to the occurrence of poor aggregation, the amount of the flocculant used increases, resulting in an increase in cost. Moreover, the sedimentation property of the particles in the raw water depends on various factors such as the amount of suspended particles contained in the raw water, the pH of the raw water, and the temperature of the raw water. Therefore, the optimum amount of the flocculant affects the optimum amount of the flocculant auxiliary agent, and further changes continuously depending on the sampling location of the raw water, weather, time zone, season, and the like.

In general, when adding coagulation aids and coagulants to the raw water of the coagulation pond, the raw water is sampled in advance and different addition amounts of coagulant aids and coagulants are used. Jar test to analyze whether the sedimentation of particles in the raw water is in a good state (a state in which a large amount of particles with good sedimentation is generated due to aggregation of suspended particles) Has been done.

An outline of general jar tests performed at water treatment facilities is described below. First, a specified amount of raw water is sampled in a plurality of (for example, six) beakers, and a coagulant aid and a coagulant are added in different amounts. Next, after rapidly stirring the raw water in each beaker (the rotational speed of the stirrer is faster than that of the slow stirring), the raw water is slowly stirred (the rotational speed of the stirrer is slower than that of the rapid stirring). The time for rapid slow and slow stirring, the rotational speed during rapid stirring, and the rotational speed during slow stirring vary depending on the operation of the water treatment facility. For example, it is set to about 1 to 10 minutes according to the characteristics. Finally, after the slow stirring is completed, the sample is allowed to settle to allow the particles to settle, and the tester visually observes the particle formation and settling conditions, and uses the observation results as a reference to optimize the coagulant aid and coagulant. The appropriate amount to be added.

As an apparatus for performing the above-mentioned conventional jar test, for example, a plurality of beakers, a plurality of stirrers (stirring blades and stirring shafts) for stirring the contents of these beakers, and a display for displaying the rotation speed of the stirrer A plurality of two-stage chemical solution injection devices for injecting a chemical solution including a flocculant into the beaker, a bottom illumination device that illuminates the bottom surface of the beaker, and a back illumination device that illuminates the back surface of the beaker, A jar tester (sample water agglomeration reaction apparatus) capable of controlling the rapid stirring time, slow stirring time, and standing time with a timer is commercially available from Miyamoto Seisakusho Co., Ltd. (see Non-Patent Document 1).

However, the above-mentioned conventional jar tester relies only on the examiner's visual observation for the evaluation of the sedimentation property of the particles, and it is possible to avoid the intervention of the negligence error of the examiner (error due to the individuality of the observer) in the evaluation result. Therefore, it is difficult to obtain a correct evaluation. In addition, since the conventional jar tester relies on visual observation, when particles are difficult to be generated due to poor aggregation or the like, the particles themselves to be evaluated cannot be visually observed, and appropriate evaluation is performed. It becomes difficult to do.

Furthermore, in the conventional jar test, the supernatant liquid present above the center in the vertical direction of the beaker is targeted for sampling. Therefore, the viewpoint of the above-mentioned conventional jar test evaluation is to visually evaluate the difference in "how neatly cleans the dirty water?" And how good particles settled. This is not the point of view. Therefore, the conventional jar test is characterized in that there is no interest in the suspended particles of the precipitated water deposited below the central portion in the beaker vertical direction (see Non-Patent Document 2).

Next, a coagulation sedimentation test apparatus named “Auto Jar Tester” is sold by Ebara Engineering Service Co., Ltd. (see Patent Document 1).

The coagulation sedimentation test apparatus first collects raw water in each of four test containers, and stirs the raw water in each test container one after another while stirring the coagulant or both the coagulant and the coagulant auxiliary agent. After adding and mixing a predetermined amount, after high-speed rotation, the mixture is stirred for a predetermined time at a low-speed rotation and left for a predetermined time. The coagulation sedimentation test apparatus collects the supernatant from a predetermined position below the water surface, measures the turbidity of the supernatant, and automatically feeds back the measurement result to the chemical injection rate control of the water purification facility.

In addition, a device for determining a coagulant injection rate named “coagulation analyzer” is sold by Metawater Corporation (see Patent Document 2).

The apparatus for determining the flocculant injection rate considers that relatively large particles, for example, particles having a particle size of 3 to 7 μm, are regarded as good particles, and when the flocculant is injected and rapidly stirred, the generation of particles starts quickly. The criterion is to consider it as a good aggregation state (particle generation state). The apparatus for determining the flocculant injection rate described above fills four test water tanks with raw water, and then injects different amounts of flocculant into the raw water in each test water tank while stirring with a stirrer. The average particle size of the particles produced by aggregation is measured with a detector and displayed on a display. The apparatus for determining the flocculant injection rate includes at least one of a time when the average particle diameter of the particles starts to increase (particle growth start time) and a time when the average number of particles starts to increase (particle increase start time). Is measured as the agglomeration start time, and an appropriate flocculant injection rate is calculated from the agglomeration start time.

Japanese Patent Laid-Open No. 2-114178 JP 2009-672 A

However, in a device based on turbidity measurement, such as the chemical injection rate control device of Patent Document 1, a state where a large amount of fine particles (suspended particles) exist and a state where a large amount of large particles exist are generated. In some cases, both are measured as the same degree of turbidity and are extremely difficult to distinguish. Originally, the sedimentation property of the particles in the raw water should be evaluated that the latter is better than the former. Therefore, the chemical injection rate control device based on the measurement of turbidity, which cannot be clearly distinguished from each other, cannot accurately evaluate the sedimentation property of particles in raw water.

In addition, since the chemical injection rate control device of Patent Document 1 collects the supernatant liquid from a height near the surface of the raw water, the amount of raw water collected for measurement is small. For example, if it is assumed that water is collected from a height near the center of the raw water, the amount of raw water collected for measurement is about half of the total amount of raw water. More specifically, for example, if the capacity of the test container is 1000 mL and the test container is filled with raw water, the total amount of raw water is about 1000 mL, whereas raw water collected for measurement The amount of is about 500 mL. A small amount of raw water collected for measurement causes a decrease in measurement accuracy. In addition, according to the study of the present inventor, rather than evaluating the sedimentation property using a cool supernatant liquid, the method of measuring and evaluating the bottom water where many heavy particles are present is measured. The accuracy is also expected to improve.

Moreover, since the determination apparatus of the coagulant injection rate of Patent Document 2 measures the time from the injection of the coagulant to the start of particle formation, the process of sedimentation after the start of particle formation begins. Ignoring particle behavior. Therefore, the sedimentation property of the particles in water cannot be accurately evaluated.

Further, as shown in FIG. 2 of Patent Document 2, the chemical injection rate control device of Patent Document 2 collects raw water from the vicinity of the center in the vertical direction of a test container (test water tank) and averages the particles. The diameter and average number of particles are measured. Therefore, the sampling range of the raw water used for measurement is limited to the vicinity of the sampling section, and it is difficult to avoid systematic errors (errors due to the characteristics of the measuring device). On the other hand, in order to avoid this bias related to sampling, methods such as increasing the sampling flow rate to try a wider range of sampling, increasing the agitation strength, and further homogenizing the test vessel Is also possible. However, in the former method, there is always an upper limit value of the set flow rate related to the accuracy of fine particle measurement, and it cannot be increased carelessly. Further, regarding the latter method, according to the study of the present inventor, a phenomenon has been observed in which particles once generated are destroyed again due to an increase in stirring strength. Therefore, there is a concern that the measurement accuracy may be lowered unless sufficient attention is paid to the location of water sampling and its method.

Also, as in Patent Document 1, the idea of collecting water from the center in the vertical direction of the test vessel is “How dirty water became clean?” According to the practice of the old jar test. The point of attention is based on the point that the measurement is based on the time difference of the suspended particles contained in the supernatant. Originally, for the phenomenon of sedimentation, which takes a relatively long time to measure, the generated particles can be evaluated only by limited sampling (water sampling) of raw water (supernatant liquid) that exists above the center of the test vessel. It is difficult to say that this is a desirable method from the viewpoint of improving measurement accuracy.

The present invention has been made in view of the above-described conventional problems, and its purpose is to settle particles in raw water when, for example, a flocculant or both a flocculant and a coagulant aid are added to raw water. A sedimentation evaluation apparatus capable of quantitatively evaluating the amount of flocculant and agglomeration aid by using the sedimentation evaluation apparatus. An object of the present invention is to provide an optimum addition amount calculation device capable of calculating with reliability.

The sedimentation evaluation apparatus according to the present invention is a sedimentation evaluation apparatus that evaluates the sedimentation of particles in raw water containing particles in order to solve the above-described problem, and a container for containing the raw water; A water collection pipe for continuously collecting and feeding the raw water from the bottom of the container, and a particle number measuring device for measuring the number of particles in the raw water fed by the water collection pipe. It is said.

According to the above configuration, the sedimentation property of the particles in the raw water can be evaluated based on the measurement result by the particle number measuring device, and the individual error of the tester does not intervene in the evaluation result unlike the conventional visual jar test. Therefore, the sedimentation property of the particles in the raw water can be quantitatively and accurately evaluated.

Also, according to the above configuration, there is a great feature in that raw water is continuously collected from the bottom of the container with a water collection pipe and the number of particles in the raw water is measured by a particle number measuring device. According to the inventor's investigation, in the test vessel during the slow stirring after the rapid stirring in the jar test, the heavy particles having already good settling are in the lower part in the test vessel, while the light particles having poor settling are inferior. Have the property of gathering above in the test container. Based on this new focus, raw water is continuously collected from the bottom of the container with a sampling tube, and the distribution characteristics in the vertical direction of the suspended particles generated in this test container are measured. The suspended particles can be handled as sedimentation characteristics. Therefore, as in

Patent Documents

1 and 2, it is considered that there is a problem in the evaluation method focusing on the behavior of the suspended particles of the supernatant liquid, the problem of evaluating using a limited sample of the supernatant of the test water, It is possible to eliminate problems related to systematic errors caused by sampling from the center of the test vessel in the vertical direction (errors due to measurement device characteristics, etc.), and the sedimentation of suspended particles is highly accurate and reliable. Can be evaluated.

The sedimentation evaluation apparatus according to the present invention rapidly stirs the raw water in the container at a relatively fast stirring speed after both the flocculant or the flocculant and the coagulant auxiliary agent are added to the raw water in the container. In addition, the raw water in the container is slowly stirred at a stirring speed relatively slower than the stirring speed of the rapid stirring, and thereafter, the stirring section for stopping the stirring and allowing the raw water in the container to stand is disposed, In addition, during the slow stirring, the raw water whose particle number has been measured by the particle number measuring device is returned to the container, and after the standing, the water returning portion for stopping the returning water and the standing The number of particles measured by the particle number measuring device in the stationary period from the start time to the time when the water level of the raw water in the container decreases to the bottom of the container and no water is fed to the particle number measuring device. It is preferable to further include a calculation unit that calculates a temporal change amount.

According to the above configuration, the raw water and the aggregating agent or both the aggregating agent and the aggregating auxiliary agent are mixed by rapid stirring, and agglomeration is quickly started. Thereafter, by slowly stirring the raw water in the container, the particles produced by the aggregation grow larger without breaking. During the stationary period after rapid stirring and slow stirring, the water return stop state is maintained, and the temporal change in the number of particles in the collected raw water is measured with a particle number measuring instrument. Thus, an evaluation index for sedimentation is obtained. The amount of change in the number of particles during this standing period indicates the vertical distribution of the number of suspended particles in the container. Large particles that have a high sedimentation capacity and settle at the bottom have a change amount per unit time. On the other hand, colloidal particles (microparticles) that decrease before and after standing but have low sedimentation ability and float to the upper layer clearly indicate the property that the amount of change per unit time increases before and after standing. Thereby, sedimentation evaluation regarding the sedimentation ability of the particles in the raw water in the container can be performed.

The particle number measuring device measures at least the number of particles in a first particle size range having a lower limit value of 1 μm or more, and the computing unit measures the first particle number measured by the particle number measuring device in the stationary period. It is preferable to calculate the amount of change over time in the number of particles in the particle size range.

According to the above configuration, the temporal change amount of the number of particles in the first particle size range in which the lower limit during the standing period is 1 μm or more can be obtained as the sedimentation evaluation index. Here, the particles having the first particle size range whose lower limit is 1 μm or more are particles having a particle size range including particles similar to colloidal particles exhibiting difficult sedimentation. The amount of change over time in the number of particles in the first particle size range during this standing period indicates the vertical distribution of the number of particles in the first particle size range in the container, and the sedimentation capacity is low, leading to the upper layer. If there are many floating colloidal particles, the amount of change over time of this measured value increases. Thereby, sedimentation evaluation regarding the sedimentation ability of the particle | grains of the 1st particle size range containing the colloidal particle in the raw | natural water in a container can be performed.

The particle number measuring device further measures the number of particles in a second particle size range larger than the first particle size range, and the computing unit is measured by the particle number measuring device in the stationary period It is preferable to further calculate the temporal change in the number of particles in the second particle size range.

According to the above configuration, the temporal change amount of the number of particles in the second particle size range that is larger than the first particle size range can be obtained as the sedimentation evaluation index. Here, the particles in the second particle size range are particles that exhibit relatively good sedimentation properties. The amount of temporal change in the number of particles in the second particle size range during this standing period indicates the vertical distribution of the number of particles in the second particle size range in the container, and the sedimentation capacity is high and settles to the bottom. If there are many particles, the amount of change over time of this measurement value decreases. Thereby, the sedimentation evaluation regarding the sedimentation ability of the particles in the second particle size range having a large particle diameter in the raw water in the container can be performed. In the above configuration, the particle number measuring device classifies (and sorts) the particle size into two or more particle size ranges, and then measures the number of particles (included in the unit flow rate) in each particle size range. be able to. Since the sedimentation property changes depending on the size of the particles, measuring the number of particles for each of a plurality of particle size ranges in this manner effectively contributes to improvement in evaluation accuracy or reliability.

It is preferable that the calculation unit further calculates an average value of the number of particles in the first particle size range measured by the particle number measuring device in the stationary period.

According to the above configuration, the average value of the number of particles in the first particle size range during the standing period can be obtained as an evaluation index for sedimentation. The average value of the number of particles in the first particle size range during this standing period indicates the absolute amount of the number of particles in the first particle size range in the container. If the generation amount is large, the measured value becomes large. Therefore, it is possible to perform sedimentation evaluation on the amount of particles that can be determined to be difficult sedimentation in the raw water in the container.

The arithmetic unit is a time of the number of particles in the second particle size range measured by the particle number measuring device in a period from the time when 1 minute or more has elapsed from the start of the rapid stirring to the end of the rapid stirring. It is preferable to further calculate a typical change amount.

According to the above configuration, the amount of change over time in the number of particles in the second particle size range in the period from the time when 1 minute or more has elapsed since the start of rapid stirring to the end of rapid stirring is determined by the weakness of the generated particles. It can be obtained as a sex evaluation index. Generally, after adding a predetermined amount of a flocculant or both a flocculant and a flocculant auxiliary agent to raw water, the agglomeration reacts vigorously at 1 to 2 minutes after the start of rapid stirring. . However, according to the study of the present inventor, when the binding of the generated particles is fragile, the particles in the second particle size range can be obtained by rapid stirring after about 1 to 2 minutes and thereafter. A decrease in the number is observed, and changes with time are obtained such that the maximum value is obtained when about 1 to 2 minutes elapse. Therefore, according to the above configuration, the fragility of the particles having the second particle size range generated during the rapid stirring after the start of aggregation is the second obtained at the time when 1 to 2 minutes have elapsed from the start of the rapid stirring. It is obtained by comparing the difference between the number of particles in the particle size range and the number of particles in the second particle size range obtained at the end of rapid stirring. That is, when it starts to decrease with the passage of time, the vulnerability of the particles in the second particle size range is recognized, whereas when it starts to increase, the vulnerability is not recognized and the production of tough particles is not observed. It can be judged that it was made. Therefore, the vulnerability of the generated particles in the raw water in the container can be evaluated.

It is preferable that the calculation unit further calculates an average value (time average value) of the number of particles in the second particle size range measured by the particle number measuring device in the stationary period.

According to the above configuration, the average value of the number of particles in the second particle size range during the stationary period can be obtained as an evaluation index of the sedimentation property of the particles. Since the average value of the number of particles in the second particle size range during this standing period indicates the absolute amount of the number of particles in the second particle size range in the container, the amount of particles having a large easily settled property in the container If there are many, the average value becomes large. Therefore, by using this average value, it is possible to perform sedimentation evaluation regarding the amount of particles that can be determined as easy sedimentation in the raw water in the container.

The bottom surface of the container may have an inverted conical shape, and the water sampling pipe may be connected to the tip of the apex of the inverted conical shape on the bottom surface of the container.

According to the above configuration, the particles at the bottom of the container at the time of water sampling move quickly toward the water sampling pipe due to its own weight and the inclination formed by the conical surface, and are sent to the particle number measuring device. Water can be collected without omission and used as a measurement target. Therefore, sedimentation evaluation with higher accuracy and reliability is possible.

The bottom surface of the container includes an inverted frustoconical surface portion and an inverted conical surface portion provided on the lower side of the inverted frustoconical surface portion, and the water sampling pipe is connected to an apex portion of the inverted conical surface portion, It is preferable that the gradient of the inverted truncated cone surface portion (inclination with respect to the horizontal plane) is gentler than the gradient of the inverted cone surface portion.

According to the above configuration, since the inverted truncated cone surface portion having a gentler slope than the inverted cone surface portion is provided on the bottom surface of the container, the floc that has settled down to the bottom surface of the container is not taken into the water sampling pipe, To deposit. Thereby, it becomes possible for an operator to easily visually check the accumulation state in which the floc settles and accumulates on the bottom surface of the container.

An optimum addition amount calculation device according to the present invention is an optimum addition amount calculation device for calculating an optimum addition amount of at least one of a flocculant and a flocculant auxiliary agent, the settling property evaluation device including a plurality of containers, The addition amount of at least one of the flocculant and the flocculant auxiliary added to the raw water in the plurality of containers, and the raw water in each container calculated by the calculation unit (1) the second in the stationary period A temporal change in the number of particles in the particle size range, (2) a temporal change in the number of particles in the first particle size range in the stationary period, and (3) the first in the stationary period. An average value of the number of particles in the particle size range of 1 and (4) the number of particles in the second particle size range in a period from the time when 1 minute or more has elapsed since the start of the rapid stirring to the end time of the rapid stirring. Based on the amount of change over time, flocculant and agglomeration It is characterized in that it comprises a optimum addition amount calculating section which calculates at least one of the optimum amount of auxiliaries.

The optimum addition amount calculation device according to the present invention calculates the optimum addition amount of at least one of the flocculant and the flocculation aid based on at least four types of sedimentation evaluation indexes calculated by the sedimentation evaluation device according to the present invention. Therefore, the optimum addition amount of at least one of the flocculant and the flocculant auxiliary agent can be calculated with good accuracy and high reliability.

An optimum addition amount calculation device according to the present invention is an optimum addition amount calculation device for calculating an optimum addition amount of at least one of a flocculant and a flocculant auxiliary agent, the settling property evaluation device including a plurality of containers, The addition amount of at least one of the flocculant and the flocculant auxiliary added to the raw water in the plurality of containers, and the raw water in each container calculated by the calculation unit (1) the second in the stationary period A temporal change in the number of particles in the particle size range, (2) a temporal change in the number of particles in the first particle size range in the stationary period, and (3) the first in the stationary period. An average value of the number of particles in the particle size range of 1 and (4) the number of particles in the second particle size range in a period from the time when 1 minute or more has elapsed since the start of the rapid stirring to the end time of the rapid stirring. The amount of change over time, and (5) before the standing period Based on the average value of the number of particles in the second particle size range, an optimum addition amount calculation unit that calculates an optimum addition amount of at least one of the flocculant and the aggregation auxiliary agent, and And an optimum addition amount calculating unit for calculating at least one optimum addition amount.

According to the above configuration, since the optimum addition amount of at least one of the flocculant and the flocculant auxiliary agent is calculated based on at least five kinds of the sedimentation evaluation indices calculated by the sedimentation evaluation apparatus according to the present invention, the flocculant and The optimum addition amount of at least one of the aggregation aids can be calculated with better accuracy and higher reliability.

As described above, according to the present invention, when the flocculant or both the flocculant and the flocculation aid are added to the raw water, the sedimentation property of the particles in the raw water is quantitatively determined with high accuracy and high reliability. It is possible to provide a sedimentation evaluation device capable of evaluating, and an optimum addition amount calculation device capable of calculating the optimum addition amount of at least one of the flocculant and the flocculant auxiliary agent with good accuracy and high reliability. .

It is the schematic which shows the optimal addition amount calculation apparatus (a sedimentation evaluation apparatus is included) which concerns on one Embodiment of this invention. It is the schematic which shows the structure of the fine particle measuring device with which the optimal addition amount calculation apparatus shown in FIG. 1 is provided. It is a figure for demonstrating the measurement principle in the fine particle measuring device with which the optimal addition amount calculation apparatus shown in FIG. 1 is provided, and the graph which shows an example which determines the magnitude | size of a particle diameter from the change of the attenuation factor of received light amount, and its change amount It is. It is a figure for demonstrating the principle of sedimentation evaluation in one Embodiment of this invention, and the change of the particle number measured with the fine particle measuring device in each of a rapid stirring period, a slow stirring period, and a stationary period. It is a graph which shows typically the state of water sampling, measurement, and water return (drainage) in each period. It is a figure for demonstrating the principle of sedimentation evaluation in one Embodiment of this invention, and is a graph which shows the example of the vertical distribution of the number of particles in a beaker. It is a flowchart which shows the flow of the optimal addition amount calculation method of at least one of the coagulant | flocculant which concerns on one Embodiment of this invention, and a coagulant auxiliary agent. It is the schematic which shows the beaker of the optimal addition amount calculation apparatus which concerns on other embodiment of this invention, and its peripheral part. It is a graph which shows the time-dependent change of the number of particles with a particle diameter of 2 μm or more and less than 5 μm measured by the fine particle measuring instrument in Example 1 of the present invention. It is a graph which shows the time-dependent change of the particle number of particle size 5 micrometers or more and less than 10 micrometers measured with the fine particle measuring device in Example 1 of this invention. It is a graph which shows a time-dependent change of the number of particles with a particle size of 10 micrometers or more measured with the fine particle measuring device in Example 1 of this invention. 6 is a graph showing the change over time in the number of particles having a particle diameter of 2 μm or more and less than 5 μm measured by a particle measuring instrument in Comparative Example 1. 5 is a graph showing the change over time in the number of particles having a particle diameter of 5 μm or more and less than 10 μm measured by a particle measuring instrument in Comparative Example 1. 6 is a graph showing the change over time in the number of particles having a particle diameter of 10 μm or more measured by a particle measuring instrument in Comparative Example 1. It is a graph which shows the time-dependent change of the number of particles with a particle diameter of 2 μm or more and less than 5 μm measured by the fine particle measuring instrument in Example 2 of the present invention. It is a graph which shows the time-dependent change of the number of particles with a particle size of 5 μm or more and less than 10 μm measured by the particle measuring instrument in Example 2 of the present invention. It is a graph which shows a time-dependent change of the number of particles with a particle size of 10 micrometers or more measured with the fine particle measuring device in Example 2 of this invention. It is a graph which shows the variation | change_quantity in the stationary period of the particle number of three types of particle size ranges measured with the fine particle measuring device in Example 2 of this invention. It is a graph which shows the time-dependent change of the number of particles with a particle diameter of 2 μm or more and less than 5 μm measured by a fine particle measuring instrument in Example 3 of the present invention. It is a graph which shows the time-dependent change of the particle number of particle size 5 micrometers or more and less than 10 micrometers measured with the fine particle measuring device in Example 3 of this invention. It is a graph which shows a time-dependent change of the number of particles with a particle size of 10 micrometers or more measured with the particle measuring device in Example 3 of this invention. It is a graph which shows the variation | change_quantity in the stationary period of the number of particles of the three types of particle size range measured with the fine particle measuring device in Example 3 of this invention. It is a graph which shows the time-dependent change of the number of particles with a particle diameter of 2 μm or more and less than 5 μm measured by the fine particle measuring instrument in Example 4 of the present invention. It is a graph which shows the time-dependent change of the number of particles with a particle size of 5 μm or more and less than 10 μm measured by the particle measuring instrument in Example 4 of the present invention. It is a graph which shows a time-dependent change of the number of particles with a particle size of 10 micrometers or more measured with the fine particle measuring device in Example 4 of this invention. It is a graph which shows the variation | change_quantity in the stationary period of the number of particles of three types of particle size ranges measured with the fine particle measuring device in Example 4 of this invention. It is the schematic which shows the beaker and its peripheral part of the optimal addition amount calculation apparatus which concerns on other embodiment of this invention. It is a flowchart which shows the flow of the optimal addition amount calculation method of at least one of the coagulant | flocculant and coagulant auxiliary agent which concern on other embodiment of this invention. It is a graph which shows the time-dependent change of the number of particles with a particle diameter of 2 μm or more and less than 7 μm measured by the fine particle measuring instrument in Example 5 of the present invention. It is a graph which shows a time-dependent change of the number of particles with a particle size of 10 micrometers or more measured with the fine particle measuring device in Example 5 of this invention. In Example 5 of the present invention, the amount of change per unit time in the number of particles having a particle size of 2 μm or more and less than 7 μm in the standing period, calculated by the calculation unit, per unit time in the number of particles having a particle size of 10 μm or more in the standing period It is a graph which shows the variation | change_quantity and the variation | change_quantity per unit time of the number of particle | grains with a particle size of 10 micrometers or more in the period A from the time when 1.5 minutes passed since the rapid stirring start to the rapid stirring end time. Graph showing the average value of the number of particles having a particle size of 2 μm or more and less than 7 μm in the standing period and the average value of the number of particles having a particle size of 10 μm or more in the standing period, calculated by the calculation unit in Example 5 of the present invention. It is.

[Embodiment 1]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic diagram of an optimum addition amount calculation apparatus according to this embodiment. The optimum addition amount calculation apparatus according to this embodiment includes four basic components, that is, a data collection / analysis unit 1, a fine particle measurement unit including a fine particle measurement device (particle number measurement device) 2, and an agitation control unit 3. And 6 beakers 4 for containing raw water containing particles such as river water, sewage, and used industrial water. The bottom surface of the beaker 4 is a plane. The number of beakers 4 is not limited to six, and may be eight or twelve.

The optimum addition amount calculation device according to the present embodiment includes a sedimentation evaluation device that evaluates the sedimentation properties of particles in raw water. The sedimentation evaluation device is a portion obtained by removing the optimum addition amount calculation unit 1b of the data collection / analysis unit 1 from the optimum addition amount calculation device.

The data collection / analysis unit 1 is a personal computer in which a data collection / analysis program is installed. The data collection / analysis unit 1 has a function of accumulating and analyzing measurement data obtained from the particle measuring instrument 2 and displaying the test result. Each unit included in the data collection / analysis unit 1 will be described later.

The fine particle measuring unit includes a fine particle measuring instrument 2, a pump 5, a filter 6, a flow meter 7, a three-way valve (returning part) 8, a water collection pipe 12, a return pipe (returning part) 13, and drainage. Tube 14. The pump 5 is connected to the bottom side surface of the beaker 4 via the water sampling pipe 12. The pump 5 continuously collects the raw water in the beaker 4 through the water sampling pipe 12 and sends the raw water to the fine particle measuring instrument 2 through the water sampling pipe 12. Water supply to the particle measuring instrument 2 by the pump 5 is controlled so that the flow rate measured by the flow meter 7 is constant.

The flow rate of sampling water from the beaker 4 is mainly determined by the size of the particle size to be measured and the measurement accuracy of the particle measuring instrument 2 related thereto. Here, in order to mainly classify and count particles having a particle size range of 2 μm or more, the flow rate of water collected from the beaker 4 is allowed to be in a flow rate range of 50 mL / min to 100 mL / min. The In general, the measurement accuracy of ultra-fine particles of 2 μm or less is improved by reducing the flow rate of water sampled from the beaker 4. However, for example, the flow velocity near the water sampling port during sampling is reduced. In order to make it difficult to collect particles far from the water sampling port of the beaker 4 and to reduce the flow velocity in the pipe, the water sampling pipe 12, the particle measuring instrument 2, the pump 5, the filter 6, the flow meter 7, There is a concern that it becomes difficult to discharge bubbles (air pockets) retained in the three-way valve (return portion) 8, the water collection pipe 12, the return pipe (return portion) 13, and the like. On the other hand, increasing the flow rate of water sampled from the beaker 4 decreases the measurement accuracy of ultrafine particles of 2 μm or less, but the particle size range (particle diameter of 2 μm or more and around 15 μm as intended in this case). The above problem can be solved satisfactorily only in the case of particles that can be classified. However, when the flow rate of water sampled from the beaker 4 exceeds 100 mL / min, the measurement accuracy is remarkably lowered even in the particle size range of interest in this case. Is preferably 50 mL / min or more, and more preferably 100 mL / min or less.

Further, it is preferable that the pump 5 has a small pulsation and does not have a temporal flow rate fluctuation. The filter 6 is provided in the middle of a water collection pipe 12 that connects the beaker 4 and the pump 5, and removes foreign substances in the raw water by filtering the raw water collected from the beaker 4. The flow meter 7 is provided in the middle of a water return pipe 13 that connects the particulate measuring device 2 and the three-way valve 8, and measures the flow rate of raw water that is sent from the beaker 4 to the particulate measuring device 2.

The three-way valve 8 is connected to the fine particle measuring instrument 2 through the water return pipe 13, connected to the upper side surface of the beaker 4 through the water return pipe 13, and connected to the drain pipe 14. The three-way valve 8 has a water return state in which the raw water drained from the particle measuring instrument 2 after the particle count is measured (measured) by the particle measuring instrument 2 is returned to the beaker 4 through the return pipe 13; Returning water is stopped, the number of particles is measured by the particle measuring instrument 2, and raw water drained from the particle measuring instrument 2 can be switched to a drained state in which the raw water is drained to the outside through the drain pipe 14. The three-way valve 8 is returned to the water return state during the rapid stirring and the slow stirring, and is switched to the drained state by a command from the data collecting / analyzing unit 1 at the time of standing thereafter. In addition, the water return state and the drainage state may be switched by combining a plurality of pipes and a plurality of on-off valves.

The fine particle measuring instrument 2 is a classification type fine particle counter that measures the number of particles in a plurality of different particle diameter ranges in the raw water fed by the water collection pipe 12. The particle measuring instrument 2 of the present embodiment includes a number of particles in a first particle size range (hereinafter referred to as “small particle size range”) having a lower limit value of 1 μm or more, and a second value larger than the first particle size range. And the number of particles in the particle size range (hereinafter referred to as “large particle size range”). The large particle size range is, for example, a particle size range of 5 μm or more and less than 10 μm, or a particle size range of 10 μm or more. The particle size measuring instrument 2 has a plurality of particle size ranges (for example, a particle size range of 2 μm or more and less than 5 μm, a particle size range of 5 μm or more and less than 10 μm, and a particle size range of 10 μm or more, 2 μm or more and less than 4 μm). 4 particle size range, 4 μm or more and less than 7 μm particle size range, 7 μm or more and less than 15 μm particle size range, and 4 particle size ranges such as 15 μm or more particle size range). Is more preferable. Thereby, evaluation accuracy can be further improved. The fine particle measuring instrument 2 of the present embodiment measures the number of particles (units / 0.1 L / min) per unit flow rate (0.1 L / min).

As shown in FIG. 2, the particle measuring instrument 2 receives a pipe 2a through which the collected raw water flows, a light emitting unit 2b that irradiates the raw water flowing through the pipe 2a with a light beam, and light that has passed through the raw water. Thus, the photoelectric shut-off measuring instrument is provided with a light receiving portion 2c that performs photoelectric conversion into an electrical signal. When the particles pass through the optical path of the light beam (light source light) emitted from the light emitting unit 2b and block the light beam, the light beam is attenuated (dimmed) and enters the light receiving unit 2c as attenuated light. In the light receiving unit 2c, the attenuation rate of light due to the passage of the particles is measured as the attenuation rate of the electric signal. The fine particle measuring device 2 determines the number of particles and the particle size from the frequency of attenuation of the amount of light received by the light receiving unit 2c and the magnitude (attenuation rate) of attenuation.

FIG. 3 shows an example of a change over time of the attenuation rate C of the amount of received light measured as the attenuation rate of the electrical signal by the light receiving unit 2c.

The number of particles is calculated by a method of counting the number of peaks in the change over time of the attenuation rate C on the assumption that one of the peaks (attenuation peak) in the change over time of the attenuation rate C corresponds to the passage of one particle. .

The particle size is determined by comparing the maximum value of each peak of the attenuation rate C with the threshold value of the attenuation rate corresponding to the boundary value of the particle size range. The threshold for the decay rate is determined in advance by calibration using standard particles having a particle size equal to the boundary value of the particle size range. What particle size range the number of particles in the particle size measuring device 2 is measured can be set as appropriate according to the evaluation target.

The particle measuring instrument 2 is set to measure the number of particles in three particle size ranges, for example, a particle size range of 2 μm or more and less than 5 μm, a particle size range of 5 to 10 μm, or a particle size range of 10 μm or more. In this case, the particle diameter is determined as follows. First, the attenuation rate due to a particle having a particle size of 2 μm is calculated as a threshold P ₂ of the attenuation rate corresponding to the particle size of 2 μm by a prior calibration using a particle having a particle size of 2 μm. Is calculated as a threshold value P ₅ of the attenuation rate corresponding to the particle size of 5 μm, and the previous calibration using the particle size of 10 μm is used to calculate the attenuation rate due to the particle of 5 μm particle size. The attenuation rate is calculated as an attenuation rate threshold P ₁₀ corresponding to a particle size of 10 μm.

When the maximum value P of the peak of the attenuation rate C is P ₁₀ or more (P ≧ P ₁₀ ) as in the maximum value P _d ^A shown in FIG. 3, the peak becomes a particle having a particle size of 10 μm or more. The number of peaks satisfying P ≧ P ₁₀ is counted as the number of particles in the particle size range of 10 μm or more. Further, when the maximum value P of the peak of the attenuation rate C is P ₅ or more (P ≧ P ₅ ) as shown in FIG. 3 such as the maximum value P _d ^A and the maximum value P _d ^B , the peak It is determined that the particle corresponds to a particle having a diameter of 5 μm or more, and the number of peaks satisfying P ≧ P ₅ is counted as the number of particles having a particle diameter of 5 μm or more. Further, the maximum value P of the peak of the attenuation rate C is equal to or greater than P ₂ (P ≧ P ₂ ) like the maximum value P _d ^A , the maximum value P _d ^B , and the maximum value P _d ^C shown in FIG. In some cases, it is determined that the peak corresponds to a particle having a particle size of 2 μm or more, and the number of peaks satisfying P ≧ P ₂ is counted as the number of particles having a particle size of 2 μm or more. Then, by subtracting the number of particles in the large particle size range of 10 μm or more from the number of particles of particle size 5 μm or more, the number of particles in the particle size range of 5 μm or more and less than 10 μm is calculated. Further, the number of particles in a particle size range of 2 μm or more and less than 5 μm is calculated by subtracting the number of particles of 5 μm or more from the number of particles having a particle size of 2 μm or more.

The fine particle measuring instrument 2 sends measurement data, that is, data on the number of particles in a plurality of particle size ranges to the data collection / analysis unit 1 respectively.

The agitating unit rotates the motor 9 in accordance with instructions from the motor 9, the rotating shaft 10 connected to the motor 9, the agitating paddle 11 provided at the tip (lower end) of the rotating shaft 10, and the data collection / analyzing unit 1. And an agitation controller 3 that electrically controls the speed and the rotation time. The stirrer rapidly stirs the raw water in the container after the flocculant or both the flocculant and the coagulant auxiliary agent are added to the raw water in the container, and then slowly stirs, and then stops stirring. And leave the raw water in the container.

The data collection / analysis unit 1 collects the measurement data sent from the particle measuring instrument 2, and calculates a temporal change amount and average value of the number of particles based on the collected measurement data, The optimum addition amount calculation unit 1b for calculating the optimum addition amount of at least one of the flocculant and the coagulation auxiliary agent based on the calculation result of the unit 1a, the calculation result of the calculation unit 1a, the calculation result of the optimum addition amount calculation unit, and the like are displayed. And a storage unit 1d for storing a data collection analysis program and various setting information. The calculation unit 1a and the optimum addition amount calculation unit 1b are functional blocks, and both are realized by a computer such as a CPU that executes a data collection analysis program stored in the storage unit 1d. The data collection and analysis program includes a part (routine) for causing the computer to function as the arithmetic unit 1a and a part for causing the computer to function as the optimum addition amount calculating unit 1b.

The calculation unit 1a (1) the raw water level in the beaker 4 is lowered to the bottom of the beaker 4 from the time when the standing is started (at the time when the slow stirring is finished), and water is supplied to the fine particle measuring device 2. The amount of change in the number of particles in the large particle size range measured by the particle size measuring instrument 2 during the stationary period until the time of disappearance, and (2) the small particle size range measured by the particle size measuring instrument 2 during the stationary period The amount of change in the number of particles per unit time, (3) the average value of the number of particles in the small particle size range measured by the fine particle measuring instrument 2 during the stationary period, and (4) one minute or more has elapsed since the start of rapid stirring The change amount per unit time of the number of particles in the large particle size range measured by the fine particle measuring device 2 in the period from the time point to the end point of the rapid stirring is calculated for each raw water of each beaker 4.

The optimum addition amount calculation unit 1b includes the addition amount of at least one of the flocculant and the flocculant auxiliary added to the raw water in each beaker 4, and the above-mentioned (1) of the raw water in each beaker 4 calculated by the calculation unit 1a. Based on the values of (4) to (4), the optimum addition amount of at least one of the flocculant and the flocculant aid is calculated.

Next, the flow of sedimentation evaluation processing in the optimum addition amount calculation apparatus according to this embodiment will be described.

First, for example, when the test object is raw water with low alkalinity, a tester adds a predetermined amount of an alkaline agent to the raw water in each beaker 4 as necessary to increase the alkalinity. As the alkaline agent, soda ash (Na ₂ CO ₃ ), slaked lime (Ca (OH) ₂ ), caustic soda (NaOH), or the like can be used. In addition, when the test object is raw water with high alkalinity, the tester can add sulfuric acid, carbonic acid, hydrochloric acid, or the like as an acid agent to the raw water in each beaker 4 as necessary. In the present embodiment, the same amount of aggregation aid may be added to the raw water in each beaker 4. On the other hand, instead of that, the coagulant auxiliary agent may be added to the raw water in each beaker 4 in different amounts. In this case, it is possible to try to determine the optimum addition amount of the coagulation aid.

First, the tester adds different amounts of flocculant to the raw water in each beaker 4. At this time, the tester inputs the coagulant addition amount of each beaker 4 to the data collection / analysis unit 1. In addition, when adding a coagulant adjuvant to the raw | natural water in each beaker 4 with a different addition amount, you may add the same quantity of flocculant to the raw | natural water in each beaker 4. FIG. In this case, it is possible to try to determine the optimum addition amount of the coagulation aid.

The flocculant and the flocculant auxiliary agent are not particularly limited, and examples thereof include PAC, sulfuric acid band, polymer flocculant, and iron-based flocculant. As the agglomeration aid, soda ash (sodium carbonate), caustic soda (sodium hydroxide), bentonite (agglomeration accelerator) and the like can also be used. The difference in the amount of flocculant added between each beaker 4 is preferably about 5 to 10 mg / L. As a method for adding the flocculant, for example, a method of injecting the liquid flocculant into the beaker 4 with a metering pump or a syringe pump can be used.

Next, the tester inputs an instruction to start sedimentation evaluation to the data collection / analysis unit 1 by a key operation or the like. When an instruction to start sedimentation evaluation is input, the data collection / analysis unit 1 sends a rapid stirring start command to the stirring control unit 3, and the stirring control unit 3 determines the rotation speed of the motor 9 according to the rapid stirring start command. To control the rotation speed. Thereby, the stirring paddle 11 stirs the raw water in each beaker 4 at a rapid stirring speed. The speed of rapid stirring is preferably set in accordance with the characteristics of the coagulation pond of each water treatment facility.

The rapid stirring of the raw water in each beaker 4 continues for a preset time (rapid stirring time) that is longer than the time (aggregation start time) required from the start of rapid stirring to the start of aggregation. The time during which aggregation is noticeable is 1 to 2 minutes from the start. The rapid stirring time is preferably set in accordance with the characteristics of the coagulation pond of each water treatment facility. In this embodiment, in order to measure the amount of change in the number of particles in a period from the lapse of 1 to 2 minutes after the start of rapid stirring to the end of rapid stirring, the rapid stirring time is more preferably 2 minutes or more.

During rapid stirring, the raw water in the beaker 4 is continuously collected from the bottom of the beaker 4 by the water collection pipe 12 and sent to the fine particle measuring device 2, and the number of particles in the fed raw water is measured by the fine particle measuring device 2. (Measurement) The raw water after measurement is returned to the upper part of the beaker 4 by the three-way valve 8 and the water return pipe 13. Fine instrument 2, the number of particles P ₁ of the large size range after 1-2 minutes rapid stirring start has elapsed, a particle number P _A of large particle size range during rapid completion of the stirring, at rapid completion of stirring The number of particles P _{A in} the small particle size range is measured, and the measured value is sent to the calculation unit 1a. The calculation unit 1a subtracts the aggregation start time (1 to 2 minutes) from the rapid stirring time stored in advance in the storage unit 1d of the data collection / analysis unit 1. Further, the calculation unit 1a calculates the value t _A obtained by the subtraction (the length of the period from the time when 1 to 2 minutes have elapsed from the start of rapid stirring to the end of rapid stirring) and the number P of particles in a large particle size range. ₁ and the number of particles P _A , the change in the number of particles per unit time (P _A −P ₁₎ in a large particle size range in a period A from the time when 1 to 2 minutes have elapsed from the start of rapid stirring to the end of rapid stirring. ) / T _A is calculated. The calculation part 1a displays the calculation result of each beaker 4 on the display part 1c. For example, the calculation unit 1a shows the relationship between the addition amount of the flocculant in each beaker 4 and the value of the number of particles per unit time change (P _A −P ₁ ) / t _A in the large particle size range in the period A. The graph is displayed on the display unit 1c.

During rapid stirring, the vertical distribution of the particles in the beaker 4 is almost uniform. Therefore, the change in the number of particles per unit time (P _A −P ₁ ) / t _A in the large particle size range is large particles in the beaker 4. The amount of change over time in the number of particles in the diameter range is shown. When the change in the number of particles per unit time (P _A −P ₁ ) / t _A in the large particle size range in the period _A is (P _A −P ₁ ) / t _A <0 as indicated by the line L1 in FIG. , Indicating that the large particle size range particles produced by the initial agglomeration are decreasing during rapid agitation because the large particle size particles are fragile (usually at the same time small particle size The number of particles in the range also increases). When the change in the number of particles per unit time (P _A −P ₁ ) / t _A in the large particle size range in period _A is (P _A −P ₁ ) / t _A > 0 as indicated by line L2 in FIG. This shows that during rapid stirring after the start of aggregation, better aggregation proceeds and the number of particles in a large particle size range increases. When the change in the number of particles per unit time (P _A −P ₁ ) / t _A in the large particle size range in period _A is (P _A −P ₁ ) / t _A = 0 as indicated by line L3 in FIG. This shows that there is no change in the number of particles in a large particle size range during rapid stirring after the start of aggregation.

Thus, large particle size range speed change amount particles per unit of time in the period _{_{A (P A -P 1) /}} t as _A increases, sedimentation of the particles in the raw water in each beaker 4 is good. Therefore, the tester can know the generation state of particles in the raw water of each beaker 4 from the value of the number of particles per unit time change (P _A −P ₁ ) / t _A , and therefore, Information for judging whether the addition amount of the coagulant auxiliary agent and the addition amount of the coagulant is preferable is obtained.

When the rapid stirring time has elapsed from the start of rapid stirring, the data collection / analysis unit 1 sends a slow stirring start command to the stirring control unit 3, and the stirring control unit 3 increases the rotation speed of the motor 9 according to the slow stirring start command. Reduce to slow stirring speed. Thereby, the stirring paddle 11 stirs the raw water in each beaker 4 slowly at a stirring speed relatively slower than the rapid stirring speed. The stirring speed of the slow stirring is preferably set in accordance with the characteristics of the coagulation pond of each water treatment facility.

The slow stirring of the raw water in each beaker 4 is continued for a preset time (slow stirring time) t _B. The slow stirring time is preferably set according to the characteristics of the coagulation pond of each water treatment facility. In the present embodiment, the slow stirring time is set to about 3 to 10 minutes for the purpose of favorably discriminating the particle generation state and the sedimentation state from the start of the slow stirring to the end of the slow stirring. More preferred.

Even during slow stirring, the raw water in the beaker 4 is continuously collected from the bottom of the beaker 4 by the water collection pipe 12 and sent to the fine particle measuring device 2, and the number of particles in the fed raw water is measured by the fine particle measuring device 2. The measured raw water is returned to the upper part of the beaker 4 by the three-way valve 8 and the water return pipe 13.

Fine instrument 2, and a particle number P _B of a large size range of slow agitation at the end, of small particle size range during slow stirring terminated and the number of particles P _B were respectively measured, calculating their measurements Send to part 1a. Computing section 1a includes a slow agitation time t _B, which is previously stored in the storage unit 1d of the data collection and analysis unit 1, a large size range and smaller size range of rapid stirring at the end (slow stirring at the start) Change in the number of particles per unit time in the large particle size range and the small particle size range during the slow stirring period from the particle number P _A and the large particle size range at the end of the slow stirring and the particle number P _{B in the} small particle size range The quantity (P _B -P _A ) / t _B is calculated.

The change in the number of particles per unit time (P _B −P _A ) / t _B during the slow stirring period mainly indicates the increase or decrease in the number of particles in the beaker 4 over time. However, since the stirring effect is slow during slow stirring, the heavy particles in the beaker 4 move to the bottom of the beaker 4 over time, and the light particles in the beaker 4 move to the upper layer of the beaker 4. There is also a state to move to. When the amount of change in the number of particles per unit time (P _B -P _A ) / t _B in the slow stirring period is (P _B -P _A ) / t _B <0 as shown by the line L4 in FIG. It shows that the number of particles in the target particle size range is decreasing during stirring. When the amount of change in the number of particles per unit time (P _B -P _A ) / t _B in the slow stirring period is (P _B -P _A ) / t _B > 0 as indicated by line L5 in FIG. It shows that the number of particles in the target particle size range is increasing during stirring. When the amount of change in the number of particles per unit time (P _B -P _A ) / t _B is (P _B -P _A ) / t _B = 0 as shown by the line L6 in FIG. It shows that there is no change in the number of particles in the target particle size range during stirring. In addition, it is preferable to consider the value of the amount of change in the number of particles per unit time (P _B −P _A ) / t _B during the slow stirring period in accordance with the state of particle formation and the state of sedimentation.

When the slow stirring time has elapsed since the start of slow stirring, the data collection / analysis unit 1 sends a slow stirring end command to the stirring control unit 3, and the stirring control unit 3 rotates the motor 9 according to the slow stirring end command. Stop. As a result, the rotation of the stirring paddle 11 is stopped, and the raw water in each beaker 4 is allowed to stand. At the same time as the rotation of the agitation paddle 11 is stopped, the three-way valve 8 is switched to the drained state by the switching instruction of the three-way valve 8 from the data collection / analysis unit 1, thereby returning the water and stopping the drainage. .

During the standing, the raw water in the beaker 4 is continuously collected from the bottom of the beaker 4 by the water collection pipe 12 and sent to the fine particle measuring device 2, and the number of particles in the fed raw water is measured by the fine particle measuring device 2. Then, the raw water after measurement is drained to the outside by the three-way valve 8 and the drain pipe 14. Therefore, during standing, the raw water in the beaker 4 decreases as the water is sent to the fine particle measuring device 2, and the water level decreases. Eventually, the water level of the raw water in the beaker 4 drops to the bottom of the beaker 4 and water supply to the fine particle measuring device 2 is not performed, and the measurement of the fine particle measuring device 2 ends at this time or just before that. From the standpoint of ensuring measurement accuracy in the particle measuring instrument 2, the time from the start of standing to the end of measurement (standing time) is not to change the sampling flow rate but to increase or decrease the capacity of the beaker 4 container. It is desirable to adjust with. According to the study of the present inventor, the time from the start of standing to the end of measurement (standing time) is preferably in the range of about 9 to 19 minutes.

Fine instrument 2, the number of particles P _C in the large particle size range during measurement end (point water into fine instrument 2 is not performed), the small particle size range during the end of the measurement and the number of particles P _C Measure and send the measured value to the computing unit 1a. The calculation unit 1a measures the standing time t _C from the stationary start time (end of slow stirring) to the end of measurement, and the measured standing time t _C and the end of slow stirring (at the start of standing). large particle size range of the number of particles P _B and Yurusoku stirring end (and particle number P _B of the small size range standing start), the number of particles P _C, and measurement of large particle size range during measurement end of) From the number of particles P _{C in} the small particle size range at the end, the amount of change in the number of particles per unit time (P _C −P _B ) / t _C in the large particle size range in the stationary period, and the small particles in the stationary period The amount of change in the number of particles per unit time in the diameter range (P _C -P _B ) / t _C is calculated. Further, the calculation unit 1a calculates the number of particles P _{B in} a small particle size range at the end of slow stirring (at the start of standing) and the number P _C of particles in a small particle size range at the end of measurement in the stationary period. The average value (P _C + P _B ) / 2 of the number of particles in the small particle size range is calculated.

The amount of change in the number of particles per unit time (P _C −P _B ) / t _C during the standing period substantially indicates the vertical distribution characteristic of the number of particles in the beaker 4 formed at the end of the slow stirring shown in FIG. Heavy particles (with a relatively large particle size range) tend to be more distributed at the bottom, and light particles (with a relatively small particle size range) tend to be distributed more at the upper layer. .

When the amount of change in the number of particles per unit time (P _C -P _B ) / t _C in the stationary period is (P _C -P _B ) / t _C <0 as shown by the line L7 in FIG. It means that the distribution of the number of particles in the vertical direction in the beaker 4 decreases as it goes upward as indicated by a line L7. For example, when the amount of change in the number of particles per unit time (P _C -P _B ) / t _C in a large particle size range during the standing period is (P _C -P _B ) / t _C <0, This means that the number of such heavy particles is larger at the bottom and less at the upper layer due to the tendency to settle. According to the study of the present inventor, particles having a large and large particle size range with good sedimentation exhibit a time-dependent change as shown by line L7 in FIG. 4 and a vertical distribution as shown by line L7 in FIG. There are many.

When the amount of change in the number of particles per unit time (P _C -P _B ) / t _C in the stationary period is (P _C -P _B ) / t _C > 0 as indicated by the line L8 in FIG. It means that the distribution of the number of particles in the vertical direction in the beaker 4 increases as it goes upward as indicated by a line L8. For example, if the amount of change in the number of particles per unit time (P _C -P _B ) / t _C in the small particle size range during the standing period is (P _C -P _B ) / t _C > 0, the light particles This means that the number of particles in the small particle size range is lower at the bottom and higher at the upper layer due to the difficulty of settling. According to the study of the present inventor, particles having a small and small particle size range that are not excellent in settling properties exhibit a change with time as shown by line L8 in FIG. 4 and a vertical distribution as shown by line L8 in FIG. There are many cases.

When the change in the number of particles per unit time (P _C -P _B ) / t _C in the stationary period is (P _C -P _B ) / t _C = 0 as shown by the line L9 in FIG. This means that the distribution of the number of particles in the vertical direction in the beaker 4 is uniform as indicated by a line L9. In this case, it is considered that particles having a target particle size range are uniformly distributed over the entire layer.

As described above, the smaller the amount of change in the number of particles per unit time (P _C -P _B ) / t _C in the large particle size range during the stationary period, the more the particles per unit time in the small particle size range during the stationary period The smaller the number change amount (P _C -P _B ) / t _{C, the} better the sedimentation property of the particles in the raw water of each beaker 4. Therefore, the tester can change the number of particles per unit time in a large particle size range during the standing period (P _C -P _B ) / t _C and the number of particles per unit time in the small particle size range during the standing period ( From the value of P _C -P _B ) / t _C , the sedimentation property of the particles in the raw water of each beaker 4 can be known. Therefore, at least one of the flocculant addition amount and the flocculant auxiliary addition amount of any beaker 4 ( Hereinafter, it can be known whether or not “denoted as“ flocculating agent / aggregating auxiliary agent addition amount ”” is preferable.

Moreover, the average value (P _C + P _B ) / 2 of the number of particles in the small particle size range during the standing period indicates the average number of particles in the small particle size range in each beaker 4. Therefore, the smaller the average value (P _C + P _B ) / 2 of the number of particles in the small particle size range during the standing period, the smaller the amount of hardly settled light particles generated in the raw water of each beaker 4. To do. Therefore, the tester can predict the abundance of suspended solids in the raw water of each beaker 4 from the average value (P _C + P _B ) / 2 of the number of particles in a small particle size range during the standing period. It can be known which beaker 4 has a preferable coagulant / coagulant additive addition amount.

Next, a method of calculating the optimum addition amount (optimum flocculant / aggregation auxiliary agent addition amount) of at least one of the flocculant and the flocculant auxiliary agent by the optimum addition amount calculation unit 1b will be described based on the flowchart of FIG.

First, with respect to the addition amount of the flocculant / aggregation auxiliary agent in all the beakers 4, the value of the change amount per unit time (P _C -P _B ) / t _C of the number of particles in the large particle size range in the stationary period is ascending order. . The smaller the amount of change in the number of particles in the large particle size range during the standing period per unit time (P _C -P _B ) / t _C , the better the sedimentation. The amount of change per unit time (P _C -P _B ) / t _C is small, and the sedimentation order is given in order from the addition amount of the flocculant / aggregation auxiliary agent (the smaller the change amount, the higher the rank). (S1). Furthermore, the score for the first item is assigned to each coagulant addition amount so that the score becomes higher in the order of higher rank (S1). Specifically, when the number of beakers 4 is 6, the total point accompanying the score, that is, the reference value is set to 7 points for each aggregating agent / aggregating auxiliary agent addition amount, and from the reference value, The score obtained by subtracting the rank is assigned. Therefore, 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point are assigned in descending order with respect to each flocculant / aggregation auxiliary agent addition amount.

Next, as for the addition amount of the flocculant / aggregation auxiliary agent in all the beakers 4, the amount of change per unit time (P _C -P _B ) / t _C of the number of particles in the small particle size range during the standing period is ascending order To do. The smaller the amount of change in the number of particles in the small particle size range during the standing period per unit time (P _C -P _B ) / t _C , the better the sedimentation. The amount of change per unit time (P _C -P _B ) / t _C is small, and the sedimentation order is given in order from the addition amount of the flocculant / aggregation auxiliary agent (the smaller the change amount, the higher the rank). (S2). Furthermore, 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point are assigned in the descending order with respect to the addition amount of each flocculant / aggregation auxiliary agent as the score for the second item (S2). .

Next, the average value (P _B + P _C ) / 2 of the number of particles in the small particle size range during the standing period is increased in order for the addition amount of the flocculant / aggregation assistant in all the beakers 4. Excellent in the small size range particles The average number of (P _B + P _C) / about 2 smaller precipitated in hold periods, the number of particles the average value of the small particle size range in the hold periods (P _B + P _C ) / 2 is set in order from the addition amount of the coagulant / aggregation auxiliary agent having a smaller value (the lower the value, the higher the order) (S3). Furthermore, 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point are assigned in the descending order with respect to the addition amount of each flocculant / aggregation auxiliary agent as points for the third item (S3). .

Next, with respect to the addition amount of the flocculant / aggregation auxiliary agent in all the beakers 4, the unit time of the number of particles in the large particle size range in the period A from the time when 1 to 2 minutes have elapsed from the start of rapid stirring to the end of rapid stirring. The value of the hit variation (P _A −P ₁ ) / t _A is increased in ascending order. The smaller the amount of change in the number of particles in the large particle size range in period A per unit time (P _A −P ₁ ) / t _A , the weaker and the poorer the toughness. The order of the change in the number of particles per unit time (P _A −P ₁ ) / t _A is increased in order from the addition amount of the flocculant / aggregation auxiliary agent (the higher the value, the higher the rank) (S4 ). Furthermore, 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point are assigned in the descending order with respect to the addition amount of each flocculant / aggregation auxiliary agent as points for the fourth item (S4). .

Next, for each flocculant / aggregation auxiliary agent addition amount, the four items scored in S1 to S4 are totaled (S5). Then, the addition amount of the flocculant / aggregation auxiliary agent having the highest total score is determined as the optimum addition amount (optimum solution) (S5).

In addition, in addition to summing the scores of the four items in S5, the values may be finally summed after multiplying each item by a weighting coefficient. The weighting coefficient is a coefficient for enhancing the consistency between each item and the particles actually generated in the agglomeration pond, and may be set by an independent judgment according to the convenience of the evaluator. In FIG. 6, the ranking and score of the four items are determined from the numerical values of the four items in S1 to S4, and the optimum addition amount of at least one of the flocculant and the coagulant auxiliary is determined based on the total score of the four items in S5. However, the optimum addition amount of at least one of the flocculant and the flocculant auxiliary agent may be calculated by comprehensively determining the numerical values of the four items by another method. As another method, for example, a method of calculating the optimum addition amount of at least one of the flocculant and the flocculant auxiliary by an engineering or statistical calculation formula obtained from a predetermined basis from the numerical values of four items is also available. Conceivable. As another method, in the method shown in FIG. 6, a method of omitting the ranking process in S1 to S4 and determining the score directly from the numerical values of the five items is also conceivable.

As described above, the optimum addition amount calculation device of the present embodiment can calculate the optimum addition amount of at least one of the flocculant and the flocculant auxiliary agent.

In the above embodiment, the beaker 4 having a flat bottom surface is used, and the water sampling pipe 12 is connected to the bottom side surface of the beaker 4. However, as shown in FIG. 7, a beaker 24 whose bottom surface has an inverted conical shape may be used instead of the beaker 4, and the water sampling pipe 12 may be connected to the apex portion of the inverted cone shape on the bottom surface of the beaker 24. Thereby, as compared with the above-described embodiment, particles that are not sampled at the time of water sampling and are likely to remain at the bottom of the beaker 4 move toward the water sampling tube 12 due to their own weight and are sent to the particle measuring instrument 2 ( Almost all the particles in the beaker 4 can be appropriately measured (without strongly sucking the raw water in the beaker 4 by the water pipe 12). Therefore, the use of the beaker 24 enables more accurate sedimentation evaluation. Note that the strong suction of the raw water in the beaker 4 by the water sampling tube 12 may cause the raw water to be stirred at the bottom of the beaker 4 to wind up the particles, and the generated particle lump may be destroyed carelessly. It is not preferable.

Further, in the above-described embodiment, the calculation unit 1a includes (1) the amount of change per unit time in the number of particles in the large particle size range during the stationary period, and (2) the number of particles in the small particle size range during the stationary period. The amount of change per unit time, (3) the average value of the number of particles in the small particle size range in the stationary period, and (4) in the period from the time when 1 minute or more has elapsed from the start of rapid stirring to the end of rapid stirring. The amount of change per unit time of the number of particles in a large particle size range was calculated. However, the amount of change in the number of particles may be calculated instead of the amount of change in the number of particles per unit time in the above (1), (2), and (4). Moreover, in the said embodiment, although the calculating part 1a calculated the variation | change_quantity per unit time of the particle number of said (1) (2) (4) from the value of the both ends of a corresponding period, You may calculate from three or more values. In addition, the calculation unit 1a calculates the amount of change in the number of particles during the standing period of (1) and (2) above as the number of particles at the starting point of the standing period and the number of particles slightly before the end point of the standing period. You may calculate from. Moreover, in the said embodiment, the calculating part 1a calculates the average value of the particle number of the small particle diameter range in the stationary period of said (3) from the value of the particle number of the small particle diameter range in the both ends of stationary period. However, the calculation unit 1a calculates the average value of the number of particles in the small particle size range in the stationary period of (3) above as the value of the number of particles in the small particle size range at three or more points in the stationary period. You may calculate from. Further, the calculation unit 1a may calculate only a part of the values (1) to (4). Further, the calculation unit 1a can be omitted.

The optimum addition amount calculation unit 1b may also calculate the optimum addition amount of at least one of the flocculant and the flocculant auxiliary based on only a part of the values (1) to (4). When the calculation unit 1a calculates only the values (1), (2), and (4), the optimum addition amount calculation unit 1b determines that the values (1), (2), and (4) The optimum addition amount of at least one of the flocculant and the flocculant auxiliary agent may be calculated based on the number of particles in a small particle size range at a predetermined point in the setting period. Moreover, the optimal addition amount calculation part 1b can also be abbreviate | omitted from the apparatus of FIG. 1, and the apparatus of FIG. 1 functions as a sedimentation evaluation apparatus in that case.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to these.

[Example 1]
In order to evaluate the sedimentation property of the particles in the raw water when the coagulant aid and the coagulant are added to the raw water, the number of particles in each particle size range is measured using the sedimentation evaluation apparatus shown in FIG. It was.

In this embodiment, the particle size measuring instrument 2 has a particle size range of 2 μm or more and less than 5 μm (small particle size range), a particle size range of 5 μm or more and less than 10 μm (large particle size range), and a particle size range of 10 μm or more (large particles). Experiments were performed using a classified fine particle counter set so that the number of particles in the three regions (diameter range) could be measured.

In this example, a beaker having an internal volume of 1 L, a height of 150 mm, and a diameter of 110 mm was used as each beaker 4, and a stainless steel filter having a hole diameter (roughness) of 0.51 mm was used as each filter 6.

In this example, first, 950 ml of highly turbid raw water having a temperature of 6.1 ° C., an electrical conductivity of 78 μS / cm, a turbidity of 5.9 degrees, an alkalinity of 17 degrees, and a pH of 7.3 was put in each beaker 4. . Next, a soda ash (sodium carbonate) solution as an alkaline agent was added to the raw water in each beaker 4 so as to have a concentration of 3 mg / L. Furthermore, for each of the raw water in the six beakers 4, the PAC solution as a flocculant has a concentration of 20 mg / L, 25 mg / L, 30 mg / L, 35 mg / L, 40 mg / L, and 45 mg / L. Each was added to be.

The contents of the beaker 4 were rapidly stirred for 3 minutes by the stirring paddle 11 at a stirring speed of 100 rpm. After completion of the rapid stirring, the contents of the beaker 4 were gently stirred by the stirring paddle 11 at a stirring speed of 50 rpm for 3 minutes. After completion of slow stirring, the contents of the beaker 4 were allowed to stand for 9 minutes.

In the rapid stirring period and the slow stirring period, the raw water discharged from the fine particle measuring device 2 is returned to the beaker 4 through the three-way valve 8, while in the stationary period, the raw water discharged from the fine particle measuring device 2 is returned. The water was discharged to the outside through the three-way valve 8. As a result, at the end of the stationary period, almost all raw water in the beaker 4 was sent to the particle measuring instrument 2.

The raw water was sampled from the bottom of each beaker 4 by the pump 5 over a period of 15 minutes in total of 3 minutes for the rapid stirring period, 3 minutes for the slow stirring period, and 9 minutes for the stationary period, and 100 ml / min (minutes). Water is fed to the particle measuring instrument 2 through the filter 6 at a constant flow rate, and the number of particles in the particle size range (small particle size range) of 2 μm or more and less than 5 μm is 5 μm or more and less than 10 μm (large particle size range). The number of particles and the number of particles in a particle size range (large particle size range) of 10 μm or more were measured. The measurement results are shown in FIGS.

[Comparative Example 1]
The raw water was changed to a raw water having a temperature of 5.9 ° C., an electric conductivity of 56.7 μS / cm, a turbidity of 2.3 degrees, an alkalinity of 14 degrees, and a pH of 7.4, and soda ash was not added and the raw water was collected. The same operation as in Example 1 was performed except that the watering position was changed to the middle in the vertical direction of the beaker 4 and the standing time was changed to 5 minutes, and a particle size range of 2 μm or more and less than 5 μm (small particles) The number of particles in the diameter range), the number of particles in the particle size range of 5 μm or more and less than 10 μm (large particle size range), and the number of particles in the particle size range of 10 μm or more (large particle size range) were measured. The measurement results are shown in FIGS.

When comparing Example 1 and Comparative Example 1 with different water sampling methods, the measurement accuracy is different as follows.

That is, when water is collected from the middle of the beaker 4 as in Comparative Example 1, the sampling time is about 5 minutes (at a flow rate of 100 mL / min, about 500 mL of water), and the vertical distribution that can be evaluated by the change over time. Since the range of is narrow as about half of the whole area and limited to the upper half, the evaluation based on the vertical distribution of the lower half cannot be performed. Further, when water is collected from the middle of the beaker 4 as in Comparative Example 1, the number of particles in the stationary period to be measured is measured as shown in FIG. 13, for example, as shown in FIG. Change is slight. Therefore, when water is collected from the middle of the beaker 4 as in Comparative Example 1, it is extremely difficult to accurately evaluate the sedimentation property of the particles in the raw water.

On the other hand, when water is sampled from the bottom of the beaker 4 as in Example 1, particles that can be evaluated by the amount of change in the number of particles in a standing time of about 9 minutes (about 900 mL of water sampled at a flow rate of 100 mL / min). The vertical distribution of is over almost the whole area of the beaker 4 and its range is wide. Further, when water is collected from the bottom of the beaker 4 as in the first embodiment, since the change in the number of particles during the stationary period is measured using almost all raw water, the stationary period measured as shown in FIG. 10, for example. The number of particles changes greatly. Therefore, as in Example 1, water is sampled from the bottom of the beaker 4, and the distribution of the number of particles is grasped over almost the entire area in the vertical direction. Is highly accurate and reliable.

[Example 2]
The raw water is changed to low turbidity raw water with a temperature of 4.5 ° C., electric conductivity 68.2 μS / cm, turbidity 0.9 degree, alkalinity 16.9 degree, pH 7.2, and soda ash is added. The number of particles in a particle size range (small particle size range) of 2 μm or more and less than 5 μm (small particle size range) is counted, and the number of particles in a particle size range of 5 μm or more and less than 10 μm (large particle size range). The number of particles in a particle size range (large particle size range) of 10 μm or more was measured. The measurement results are shown in FIGS.

Further, the calculation unit 1a of the data collection / analysis unit 1 changes the number of particles having a particle size of 2 μm or more and less than 5 μm during the standing period, the amount of change of the number of particles having a particle size of 5 μm or more and less than 10 μm during the standing period, The amount of change in the number of particles having a particle diameter of 10 μm or more during the setting period was calculated. The calculation results are shown in FIG.

Further, the optimum addition amount of PAC was calculated by the optimum addition amount calculation unit 1b of the data collection / analysis unit 1 by the optimum addition amount calculation method of FIG. That is, first, with respect to the amount of PAC added to all the beakers 4, the amount of change per unit time in the number of particles having a particle size of 10 μm or more in the standing period (first sub-item of the first item; (10 μm—the amount of change in the number of particles ”) is ranked in order from the smallest value, and the points are assigned in the descending order of 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point (S1). ). In addition, regarding the amount of PAC added to all the beakers 4, the change amount per unit time of the number of particles having a particle size of 5 μm or more and less than 10 μm during the standing period (second sub-item of the first item; (5-10 μm particle number change amount) ”is ranked in ascending order, and 6 points, 5 points, 4 points, 3 points, 2 points, 1 point are assigned in order from the highest order ( S1).

Next, with respect to the amount of PAC added to all the beakers 4, the change amount per unit time of the number of particles having a particle diameter of 2 μm or more and less than 5 μm in the standing period (in Tables 1 to 6, “change in the number of particles of 2 to 5 μm in the standing period” The order was assigned in descending order of the value of “quantity”, and 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point were assigned in descending order (S2).

Next, with respect to the amount of PAC added to all the beakers 4, the average value of the number of particles having a particle size of 2 μm or more and less than 5 μm in the standing period (in Tables 1 to 6, “the average value of 2-5 μm particles in the standing period”) The order was assigned in descending order, and 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point were assigned in descending order (S3).

Next, with respect to the PAC addition amount of all the beakers 4, the change amount per unit time of the number of particles having a particle diameter of 10 μm or more in the rapid stirring period A after 1.5 minutes (first sub-item of the fourth item; table) 1 to 6 are ranked in descending order of the value of “10 μm in the rapid stirring period after 1.5 minutes—the amount of change in the number of particles”), and are ranked in descending order of 6 points, 5 points, 4 points, 3 Points, 2 points, and 1 point were assigned (S4). Regarding the amount of PAC added to all the beakers 4, the amount of change in the number of particles having a particle size of 5 μm or more and less than 10 μm in the rapid stirring period A after 1.5 minutes (second sub-item of the fourth item; Table 1) ~ 6 are marked in descending order of the value of “the amount of change in the number of 5-10 μm particles in the rapid stirring period after 1.5 minutes”), and are ranked in descending order of 6 points, 5 points, 4 points, 3 Points, 2 points, and 1 point were assigned (S4).

The ranking of each PAC addition amount given by S1 to S4 is shown below.

The score of each PAC addition amount assigned by S1 to S4 is shown below.

Next, for each PAC addition amount, the scores of the four items (added for the first and second sub items of S1 and the first and second sub items of S4) scored in S1 to S4 were totaled (S5) . Table 2 shows the total score of each PAC addition amount. Then, the PAC addition amount having the highest total score was determined as the optimum addition amount (S5). As a result, the highest PAC addition amount of 25 mg / L was determined as the optimum addition amount.

Example 3
Change the raw water to a medium turbid raw water with a temperature of 5.1 ° C., electrical conductivity of 63.4 μS / cm, turbidity of 2.3 degrees, alkalinity of 16 degrees and pH 7.4, and no soda ash added. The number of particles having a particle size range (small particle size range) of 2 μm or more and less than 5 μm (small particle size range), the number of particles having a particle size range of 5 μm or more and less than 10 μm (large particle size range), and The number of particles in a particle size range (large particle size range) of 10 μm or more was measured. The measurement results are shown in FIGS.

Further, the calculation unit 1a of the data collection / analysis unit 1 changes the number of particles having a particle size of 2 μm or more and less than 5 μm during the standing period, the amount of change of the number of particles having a particle size of 5 μm or more and less than 10 μm during the standing period, The amount of change in the number of particles having a particle diameter of 10 μm or more during the setting period was calculated. The calculation result is shown in FIG.

Further, the optimum addition amount of PAC was calculated by the optimum addition amount calculation unit 1b of the data collection / analysis unit 1 in the same manner as in Example 2 by the optimum addition amount calculation method of FIG.

The ranking of each PAC addition amount given by S1 to S4 in FIG. 6 is shown below.

The score of each PAC addition amount assigned by S1 to S4 in FIG. 6 is shown below.

Next, for each PAC addition amount, the scores of the four items (added for the first and second sub items of S1 and the first and second sub items of S4) scored in S1 to S4 were totaled (S5) . Table 4 shows the total score of each PAC addition amount. The highest PAC addition amount was determined as the optimum flocculant addition amount (S5). As a result, the highest PAC addition amount of 25 mg / L was determined as the optimum addition amount.

Example 4
The raw water was changed to high turbidity raw water with a temperature of 6.1 ° C., electrical conductivity of 78 μS / cm, turbidity of 5.9 degrees, alkalinity of 17 degrees and pH of 7.3, except that no soda ash was added. The same operation as in Example 1 was performed, the number of particles in the particle size range (small particle size range) of 2 μm or more and less than 5 μm, the number of particles in the particle size range (large particle size range) of 5 μm or more and less than 10 μm, and 10 μm or more. The number of particles in the particle size range (large particle size range) was measured. The measurement results are shown in FIGS.

Next, for each PAC addition amount, the scores of the four items (added for the first and second sub items of S1 and the first and second sub items of S4) scored in S1 to S4 were totaled (S5) . Table 6 shows the total score of each PAC addition amount. The highest PAC addition amount was determined as the optimum flocculant addition amount (S5). As a result, the highest PAC addition amount of 30 mg / L was determined as the optimum addition amount.

[Embodiment 2]
In the first embodiment, the beaker 24 having an inverted conical bottom shape (mortar shape) shown in FIG. 7 is a floc (large particle formed by aggregation of raw water particles) when applied to low turbidity raw water. The shape was intended to improve sampling performance. That is, the beaker 24 of FIG. 7 exhibits its sampling performance in a case where the amount of flocs produced is small even when the flocculant is added, and the accuracy of sedimentation evaluation and at least one of the flocculant and the flocculant auxiliary agent are exhibited. It was good at improving the determination accuracy of the optimal addition amount.

However, when the beaker 24 of FIG. 7 is applied to raw water with high turbidity that can generate flocs relatively easily and in large quantities, due to its high sampling performance, at least one of the flocculant and the flocculant auxiliary agent. The possibility of making the work of determining the optimum addition amount (drug injection rate) rather difficult is undeniable. This is because the flocs accumulated on the inverted conical surface portion (bottom surface) of the beaker 24 gradually slide down the reverse conical surface portion over time when the generated floc increases significantly in the case of high turbidity raw water. This is because of the conspicuousness. As a result, flocs that should be observed in the initial stage of standing are observed from the middle to the end of the standing period with a time delay, and the number of particles having a particle size of 10 μm or more in the standing period is observed. Change per unit time (first sub-item of the first item used in S1) and change per unit time of the number of particles having a particle size of 5 μm or more and less than 10 μm in the stationary period (second sub-item of the first item used in S1) ) Makes it impossible to accurately estimate the flock generation status. As a specific qualitative tendency, it is suggested that the value of the amount of change that should originally be observed as a small value is observed as a large value.

7 was evaluated by a worker at the site of the water purification plant, the worker was able to see the deposition situation where the flock settled and deposited on the bottom surface of the beaker 24. It has been found that the beaker 24 is also regarded as important in that it can be visually recognized. In the beaker 24 of FIG. 7, since the floc that has settled down to the bottom surface of the beaker 34 is immediately taken into the water sampling pipe 12, the worker can visually check the accumulation state in which the floc settles and accumulates on the bottom surface of the beaker 24. It is difficult.

In view of the above two problems, the optimum addition amount calculation device according to the present embodiment has a configuration including a beaker 34 shown in FIG. 26 instead of the

beaker

4 or 24 in the first embodiment. As shown in FIG. 26, the beaker 34 includes an inverted conical surface portion 34a and an inverted frustoconical surface portion 34b provided on the upper side of the inverted conical surface portion 34a. It is connected to the apex portion, and the gradient of the inverted truncated cone surface portion 34b is gentler than the gradient of the inverted truncated cone surface portion 34a (the inverted truncated cone surface portion 34b has higher horizontality than the inverted truncated cone surface portion 34a). It has been found that the beaker 34 having this shape can solve the two problems described above.

That is, the beaker 34 is provided with an inverted conical surface portion 34a similar to the bottom surface of the beaker 24 in FIG. 7 at the lower and central side of the bottom surface, so that it remains at the bottom of the beaker 4 without being sampled during sampling. Easy particles move toward the water sampling tube 12 by their own weight and are sent to the particle measuring instrument 2. Therefore, the beaker 34 has a high flock sampling performance like the beaker 24 of FIG. 7 and can appropriately measure almost all the particles in the beaker 4.

In addition, the bottom surface of the beaker 34 is provided with an inverted truncated cone surface portion 34b having a gentler slope than the inverted cone surface portion 34a so as to surround the upper end of the inverted cone surface portion 36 above and outside the inverted cone surface portion 34a. The floc that has settled down to the bottom surface of the beaker 34 is not immediately taken into the water sampling pipe 12, but is deposited on the inverted truncated cone surface portion 34b. Thereby, it becomes possible for an operator to easily visually recognize the deposition state in which the flock settles and accumulates on the bottom surface of the beaker 34, and the visibility of the deposition state of the sedimented flock is also improved. As a result, the operator considers both the output result of the optimum addition amount calculation device according to the present embodiment and the visual recognition result of the sedimentation state of the floc that settles, and at least one of the coagulant and the coagulant auxiliary is optimal. It becomes possible to determine the addition amount. In addition, it is preferable that the beaker 34 is formed of a transparent material such as glass so that the above-described deposition state can be easily recognized.

Moreover, the beaker 34 can avoid the difficulty of determining the optimum addition amount of at least one of the flocculant and the flocculant auxiliary when applied to raw water with high turbidity. This is because, among the flocks accumulated on the inverted conical surface portion 34a and the inverted frustoconical surface portion 34b, the floc required for appropriate sampling slides only on the reverse conical surface portion 34a, and the inverted conical surface portion 34b having a relatively gentle slope. In, continue to stay there without sliding down. Therefore, “the flocs that should be observed in the initial stage of standing still are observed in the middle to the end of the standing period with a time delay, and the particles having a particle size of 10 μm or more in the standing period” The generation state of flocs cannot be accurately estimated by the change amount per unit time and the change amount per unit time of the number of particles having a particle size of 5 μm or more and less than 10 μm in the stationary period. ” .

The slope (angle with respect to the horizontal plane indicated by a broken line in FIG. 26) α of the inverted conical surface portion 34a is preferably less than 90 degrees in order to improve the sampling performance of the beaker 34. The gradient α of the inverted conical surface portion 34a is 60 degrees or more in order to avoid the difficulty of determining the optimum addition amount of at least one of the flocculant and the flocculant auxiliary when applied to high turbidity raw water. It is preferable that

The gradient β of the inverted truncated cone surface part 34b is preferably larger than 0 degrees in order to make the sampling performance of the beaker 34 better. In addition, the inverted truncated cone surface part 34b has an extremely gentle gradient β so that the worker can more easily visually recognize the accumulation state where the flock settles and accumulates on the bottom part of the beaker 34, and has sufficient horizontality. A certain shape is preferred. Specifically, the gradient β of the inverted truncated cone surface portion 34b is preferably less than 60 degrees.

The ratio of the diameter of the lower end of the inverted truncated cone surface part 34b (the diameter of the upper end of the inverted truncated cone part 34a) to the diameter of the upper end of the inverted truncated cone surface part 34b is 31.6 in order to improve the sampling performance of the beaker 34. % Or more is preferable. Further, the ratio of the diameter of the lower end of the inverted truncated cone surface part 34b to the diameter of the upper end of the inverted truncated cone surface part 34b is such that the worker can more easily visually check the accumulation state where the flock settles and accumulates on the bottom of the beaker 34. It is preferable that it is 94.9% or less so that it can do.

[Embodiment 3]
The calculation method of the optimum addition amount shown in the flowchart of FIG. 6 in Embodiment 1 mainly applies low turbidity raw water. Therefore, when applied to high turbidity raw water, there are the following problems. It was.

That is, the method of FIG. 6 does not calculate (determine) the optimum addition amount using the calculation criterion (determination criterion) regarding the generation amount (absolute amount at the time of standing) of the number of particles in a large particle size range. As a result, it is comparatively more difficult when “the number of particles generated in the large particle size range and the number of particles generated in the small particle size range are both small, but the generated flocs have some time sedimentation”. A high score was assigned, and the addition amount of the flocculant / aggregation aid in that case tended to be calculated as the optimum addition amount. For this reason, when the method of FIG. 6 is applied to raw water with high turbidity, there is a possibility that the correct optimum addition amount cannot be calculated.

As will be described below, the optimum addition amount calculation device of the present embodiment adds this calculation criterion regarding the generation amount of the number of particles in a large particle size range as the fifth item of the calculation criterion for the optimum addition amount. Is a solution.

The optimum addition amount calculation device of the present embodiment is the same as the optimum addition amount calculation device of the first embodiment, except that the functions of the calculation unit 1a and the optimum addition amount calculation unit 1b are different from the optimum addition amount calculation device of the first embodiment. It has the same configuration as

In addition to the function provided in the calculation unit 1a of the first embodiment, the calculation unit 1a of the present embodiment has particles with a large particle size range at the end of the slow stirring (at the start of standing) measured by the fine particle measuring device 2. The average value (PC + PB) / 2 of the number of particles in the large particle size range during the standing period is calculated for each beaker 4 from the number PB and the number PC of particles in the large particle size range at the end of measurement measured by the particle measuring instrument 2. It has a function to calculate for each raw water.

The optimum addition amount calculation unit 1b of the present embodiment uses the method shown in the flowchart of FIG. 27 instead of the method of FIG. 6, and uses the optimum addition amount (optimum flocculant / (Aggregating auxiliary agent addition amount) is calculated.

In the method of FIG. 27, first, as in S1 of FIG. 6, the amount of change per unit time of the number of particles in the large particle size range during the standing period (about the addition amount of the flocculant / aggregation auxiliary agent in all the beakers 4 ( PC-PB) / tC value is set in descending order from the addition amount of the flocculant / aggregation auxiliary agent, and the score for the first item is increased so that the rank is higher in order of the rank for each flocculant addition amount. Scores are assigned (S11).

Next, in the same manner as in S2 of FIG. 6, the change amount per unit time of the number of particles in a small particle size range during the standing period (PC-PB) / The order of sedimentation is assigned in order from the addition amount of the coagulant / aggregation auxiliary agent with the smallest tC value, and the score for the second item is assigned in order of the higher rank for each coagulant / aggregation auxiliary agent addition amount (S12). .

Next, in the same manner as in S3 of FIG. 6, the flocculant having a small average value (PB + PC) / 2 of the number of particles in the small particle size range during the standing period with respect to the addition amount of the flocculant / aggregation auxiliary agent in all the beakers 4 The order of sedimentation is given in order from the addition amount of the coagulant / auxiliary agent, and the score for the third item is assigned in descending order with respect to the addition amount of the coagulant / aggregation agent (S13).

Next, in the same manner as in S4 of FIG. 6, the addition amount of the flocculant / aggregation auxiliary agent in all the beakers 4 is large in the period A from the time when 1 to 2 minutes have elapsed from the start of rapid stirring to the end of rapid stirring. The order of change of the number of particles in the particle size range per unit time (P _A -P ₁ ) / t _A is ascending in order from the addition amount of the flocculant / aggregation auxiliary agent. On the other hand, the score for the fourth item is assigned in descending order (S14).

Next, the average value (P _B + P _C ) / 2 of the number of particles in the large particle size range during the standing period is increased in order for the addition amount of the flocculant / aggregation auxiliary agent in all the beakers 4. Excellent in large size range particles The average number of (P _B + P _C) / approximately two larger precipitated in hold periods, the number of particles the average value of the large particle size range in the hold periods (P _B + P _C ) / 2 is assigned in descending order of the coagulant / aggregation auxiliary agent addition amount (the higher the value, the higher the order) (S15). Furthermore, 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point are assigned in the descending order with respect to the addition amount of each flocculant / aggregation auxiliary agent as points for the fifth item (S15). .

Next, for each coagulant / coagulant auxiliary agent addition amount, the five items scored in S11 to S15 are totaled (S16). Then, the addition amount of the flocculant / aggregation auxiliary agent having the highest total score is determined as the optimum addition amount (optimum solution) (S16).

As described above, in this embodiment, by adding the average value (P _B + P _C ) / 2 of the number of particles in the large particle size range during the standing period to the calculation standard for the optimum addition amount, Whether applied to raw water or low turbidity raw water, the reliability of calculation of the optimum addition amount can be improved.

In S16, in addition to summing the scores of the five items, each item may be finally summed after being multiplied by a weighting factor. The weighting coefficient is a coefficient for enhancing the consistency between each item and the particles actually generated in the agglomeration pond, and may be set by an independent judgment according to the convenience of the evaluator. In FIG. 27, the ranking and score of the five items are determined from the numerical values of the five items in S11 to S15, and the optimum addition amount of at least one of the flocculant and the coagulant auxiliary is determined based on the total score of the five items in S16. However, the optimal addition amount of at least one of the flocculant and the flocculant auxiliary agent may be calculated by comprehensively judging the numerical values of the five items by another method. As another method, for example, there is a method of calculating the optimum addition amount of at least one of the flocculant and the flocculant auxiliary by an engineering or statistical calculation formula obtained from a predetermined basis from numerical values of five items. Conceivable. As another method, in the method of FIG. 27, a method of omitting the ranking process in S11 to S15 and determining the score directly from the numerical values of the five items is also conceivable.

The results of an experiment in which the optimum amount of flocculant added to the raw water was calculated (predicted) by the method of FIG.

Example 5
In order to evaluate the sedimentation property of the particles in the raw water when the coagulant aid and the coagulant are added to the raw water, the number of particles for each particle size range is measured using the settling property evaluation apparatus of the third embodiment described above. went.

In the present embodiment, the fine particle measuring instrument 2 can measure the number of particles in two regions of a particle size range (small particle size range) of 2 μm or more and less than 7 μm, a particle size range of 10 μm or more (large particle size range). The experiment was conducted using the set classification fine particle counter.

In this example, the same beaker 4 and filter 6 used in Example 1 were used.

In this embodiment, first, 950 ml of highly turbid raw water having a temperature of 13 ° C., an electric conductivity of 68.4 μS / cm, a turbidity of 19.8 degrees, an alkalinity of 15.0 degrees, and a pH of 7.13 is placed in each beaker 4. I put it in. Furthermore, for each of the raw water in the six beakers 4, the PAC solution as a flocculant has a concentration of 15 mg / L, 20 mg / L, 25 mg / L, 30 mg / L, 35 mg / L, and 40 mg / L. Each was added to be.

In this example, rapid stirring, slow stirring, and standing were performed under the same conditions as in Example 1. Further, in the present embodiment, in the same manner as in the first embodiment, water is collected from each beaker 4 to the particle measuring instrument 2, the raw water is returned from the particle measuring instrument 2 to the beaker 4, and the particle measuring instrument 2 is connected to the outside. Drained.

In this example, the number of particles having a particle size range of 2 μm or more and less than 7 μm (small particle size range) over a total period of 15 minutes, that is, a rapid stirring period of 3 minutes, a slow stirring period of 3 minutes, and a stationary period of 9 minutes, The number of particles in a particle size range (large particle size range) of 10 μm or more was measured by the fine particle measuring instrument 2. FIG. 28 shows the change over time in the number of particles in the particle size range (small particle size range) of 2 μm or more and less than 7 μm. FIG. 29 shows the change over time in the number of particles in the particle size range (large particle size range) of 10 μm or more.

Further, the calculation unit 1a of the data collection / analysis unit 1 uses the average value of the number of particles having a particle size of 2 μm or more and less than 7 μm in the standing period, and the average value of the number of particles having a particle size of 10 μm or more in the standing period (Tables 7 and 8). Is expressed as “10 μm of standing period—average value of the number of particles”), and the change amount per unit time of the number of particles having a particle diameter of 2 μm or more and less than 7 μm in the standing period (in Tables 7 and 8, “2- The amount of change in the number of particles having a particle size of 10 μm or more in the standing period ”(referred to as“ 10 μm in the standing period−the amount of change in the number of particles ”in Tables 7 and 8) , And the amount of change per unit time of the number of particles having a particle size of 10 μm or more in the period A from the time when 1.5 minutes have elapsed from the start of rapid stirring until the end of rapid stirring (in Tables 7 and 8, “rapidly after 1.5 minutes” 10 μm during the stirring period-the amount of change in the number of particles " Calculated). The calculation results are shown in FIG. 30 and FIG.

Here, for comparison with the present example, the optimum addition amount of PAC was calculated by the optimum addition amount calculation method of FIG. 6 using the calculation criteria of four items. Table 7 shows the scores of the four items of each PAC addition amount assigned by S1 to S4 in FIG. 6 and the total score of each PAC addition amount.

In the optimum addition amount calculation method of FIG. 6, the PAC addition amount of 25 mg / L having the highest total score of the four items was calculated as the optimum addition amount.

However, when the PAC addition amount is 25 mg / L, the number of particles having a particle diameter of 2 μm or more and less than 7 μm is small (absolute amount at the time of standing), but the unit time of the number of particles having a particle diameter of 10 μm or more in the standing period It is suggested that the amount of change per hit is the smallest and the number of particles having a particle size of 10 μm or more (absolute amount at the time of standing) is the smallest, which is not optimal. In view of the high turbidity situation in which the turbidity of the raw water is 19 degrees, the optimum addition amount calculation method in FIG. 6 does not take into account the number of large-sized particles having a particle diameter of 10 μm or more, so that the wrong optimum This suggests the possibility of leading the calculation of the addition amount.

In this example, the optimum addition amount calculation unit 1b of the data collection / analysis unit 1 calculated the optimum addition amount of PAC by the optimum addition amount calculation method of FIG.

That is, first, with respect to the amount of PAC added to all the

beakers

4, 6 points, 5 points, in order from the lowest value of the amount of change per unit time (first item) of the number of particles having a particle size of 10 μm or more in the stationary period, Four points, three points, two points, and one point were assigned (S11). In this example, as can be seen from FIG. 29 and FIG. 30, the value of the amount of change per unit time of the number of particles having a particle diameter of 10 μm or more in the standing period (lower when the settling property during standing is large) is The PAC addition amount was 20 mg / L, the PAC addition amount was 30 mg / L, the PAC addition amount was 35 mg / L, the PAC addition amount was 40 mg / L, the PAC addition amount was 15 mg / L, and the PAC addition amount was 25 mg / L. .

Next, with respect to the amount of PAC added to all the

beakers

4, 6 points and 5 points in order from the lowest value (second item) of the amount of change in the number of particles having a particle diameter of 2 μm or more and less than 7 μm in the standing period. Four points, three points, two points, and one point were assigned (S12). In this example, as can be seen from FIG. 28 and FIG. 30, the value of the amount of change per unit time in the number of particles having a particle size of 2 μm or more and less than 7 μm in the standing period (lower when the settling property during standing is large). The PAC addition amount was 25 mg / L, the PAC addition amount was 30 mg / L, the PAC addition amount was 15 mg / L, the PAC addition amount was 35 mg / L, the PAC addition amount was 40 mg / L, and the PAC addition amount was 20 mg / L. Scored.

Next, with respect to the amount of PAC added to all the

beakers

4, 6 points, 5 points, 4 points, 3 points, in ascending order of the average value (third item) of the number of particles having a particle size of 2 μm or more and less than 7 μm in the standing period. Points, 2 points, and 1 point were assigned (S13). In this example, as can be seen from FIG. 28 and FIG. 31, the average value of the number of particles in the particle size range of 2 μm or more and less than 7 μm in the standing period (the amount generated during standing) is PAC addition amount 25 mg / L, The PAC addition amount was 15 mg / L, the PAC addition amount was 40 mg / L, the PAC addition amount was 30 mg / L, the PAC addition amount was 20 mg / L, and the PAC addition amount was 35 mg / L.

Next, with respect to the amount of PAC added to all the beakers 4, the value of the amount of change per unit time (number 4) of the number of particles having a particle size of 10 μm or more in the rapid stirring period A after 1.5 minutes has elapsed is high. In order, 6 points, 5 points, 4 points, 3 points, 2 points, and 1 point were assigned (S14). In this example, as can be seen from FIG. 30, the value of the amount of change per unit time of the number of particles having a particle size of 10 μm or more in the rapid stirring period A after 1.5 minutes (strong resistance to breakage during rapid stirring) PAC addition amount 25 mg / L, PAC addition amount 15 mg / L, PAC addition amount 30 mg / L, PAC addition amount 35 mg / L, PAC addition amount 40 mg / L, PAC addition amount 20 mg / L. Because they were expensive, they were assigned in this order.

Next, with respect to the PAC addition amount of all the

beakers

4, 6 points, 5 points, 4 points, 3 points, in descending order of the average value of the number of particles having a particle diameter of 10 μm or more in the standing period (fifth item), Two points and one point were assigned (S15). In this example, as can be seen from FIG. 29 and FIG. 31, the average value of the number of particles in the particle size range of 10 μm or more in the standing period (the amount generated during standing) is PAC addition amount 20 mg / L, PAC addition The amount was 30 mg / L, PAC addition amount 35 mg / L, PAC addition amount 40 mg / L, PAC addition amount 15 mg / L, and PAC addition amount 25 mg / L in this order.

The score of 5 items of each PAC addition amount assigned by S11 to S15 is shown below.

Next, for each PAC addition amount, the scores of the five items assigned in S11 to S15 were totaled (S5). Table 8 shows the total score of each PAC addition amount. Then, the PAC addition amount having the highest total score was determined as the optimum addition amount (S5). Thereby, the PAC addition amount 30 mg / L having the highest total score of the five items was calculated as the optimum addition amount.

As a final result, the PAC addition amount of 30 mg / L, which is average or above average in all items and is suggested to be optimal, is the first item (number of particles having a particle size of 10 μm or more in the stationary period). Change per unit time) and the fifth item (average value of the number of particles having a particle size of 10 μm or more in the standing period) is the lowest and is slightly different from the PAC addition amount of 25 mg / L, which is suggested to be not optimal. However, it was calculated as the optimum addition amount.

From the above results, when this device was applied to high turbidity raw water, the fifth item (average value of the number of particles having a particle size of 10 μm or more in the stationary period) was introduced into the calculation standard for the optimum addition amount. It was found that the reliability of calculation of the optimum addition amount was improved.

From the above results, the fifth item (average value of the number of particles having a particle size of 10 μm or more in the stationary period) is used as the calculation criterion for the optimum addition amount even when the present apparatus is applied to low turbidity raw water. It is considered that the reliability of calculation of the optimum addition amount is improved by introducing. In general, it is empirically known that low turbidity raw water produces fewer large-sized particles, but large-sized particles are also better settled than small-sized particles. Empirically known. Therefore, the fifth item represents the presence (absolute value) of large-diameter particles that are likely to settle regardless of the degree of raw water turbidity. Therefore, even though the introduction of the fifth item can improve the reliability of the calculation of the optimum addition amount, it cannot be a reason for hindering this.

In the present invention, in order to determine the amount of at least one of the flocculant and the flocculant auxiliary agent added to the raw water in a water treatment facility or the like, the flocculant or both the flocculant and the flocculant auxiliary agent are variously added to the sampled raw water. Jar test that evaluates whether the sedimentation property of the particles in the raw water is in a good state, determination of the addition amount of at least one of the flocculant and the coagulant auxiliary based on the result of the jar test, etc. Available to:

DESCRIPTION OF SYMBOLS 1 Data collection and analysis part 1a Operation part 1b Optimal addition amount calculation part 2 Fine particle measuring device 3 Stirring control part (stirring part)
4,24,34 Beaker (container)
5 Pump 8 Three-way valve (return part)
9 Motor (stirring section)
10 Rotating shaft (stirring section)
11 Stir paddle (stirring section)
12 Water sampling pipe 13 Water return pipe (water return section)
14 Drain pipe 34a Reverse conical surface part 34b Reverse conical surface part

Claims

A sedimentation evaluation apparatus for evaluating the sedimentation of particles in raw water containing particles,
A container for containing the raw water;
A water collection pipe for continuously collecting and feeding the raw water from the bottom of the container;
A sedimentation evaluation apparatus comprising: a particle number measuring device for measuring the number of particles in the raw water fed by the water sampling pipe.
The sedimentation evaluation apparatus according to claim 1,
After the flocculant is added to the raw water in the container, the raw water in the container is rapidly stirred at a relatively high stirring speed, and then the raw water in the container is stirred at a relatively slower stirring speed than that of the rapid stirring. Agitating part, and then stirring is stopped and the raw water in the container is allowed to stand,
At the time of the rapid stirring and the slow stirring, the raw water whose particle number has been measured by the particle number measuring device is returned to the container, and when it is allowed to stand thereafter, a water return unit for stopping the water return,
Measured by the particle number measuring instrument in the stationary period from the time when the standing is started until the level of the raw water in the container drops to the bottom of the container and the water is not fed to the particle number measuring instrument. A sedimentation evaluation apparatus, further comprising a computing unit that computes the amount of change in the number of particles.
It is a sedimentation evaluation apparatus according to claim 2,
The particle number measuring device measures at least the number of particles in a first particle size range having a lower limit of 1 μm or more;
The settling property evaluation apparatus, wherein the calculation unit calculates a temporal change amount of the number of particles in the first particle size range measured by the particle number measuring device in the stationary period.
It is a sedimentation evaluation apparatus according to claim 3,
The particle number measuring device further measures the number of particles in a second particle size range larger than the first particle size range;
The settling property evaluation apparatus, wherein the calculation unit further calculates a temporal change amount of the number of particles in the second particle size range measured by the particle number measuring device in the stationary period.
The sedimentation evaluation apparatus according to claim 4, wherein
The said calculating part further calculates the average value of the particle number of the said 1st particle size range measured with the said particle number measuring device in the said stationary period, The sedimentation evaluation apparatus characterized by the above-mentioned.
It is a sedimentation evaluation apparatus according to claim 5,
The calculation unit is configured to measure the number of particles in the second particle size range measured by the particle number measuring device in a period from the time when 1 minute or more has elapsed from the start of the rapid stirring to the end of the rapid stirring. A sedimentation evaluation apparatus characterized by further calculating the amount of change.
The sedimentation evaluation apparatus according to claim 6, wherein
The said calculating part further calculates the average value of the particle number of the said 2nd particle size range measured with the said particle number measuring device in the said stationary period, The sedimentation evaluation apparatus characterized by the above-mentioned.
The sedimentation evaluation apparatus according to any one of claims 1 to 7,
The bottom surface of the container has an inverted conical shape,
The water collection pipe is connected to a vertex portion of an inverted conical shape on the bottom surface of the container.
The sedimentation evaluation apparatus according to any one of claims 1 to 7,
The bottom surface of the container includes an inverted conical surface portion and an inverted frustoconical surface portion provided on the upper side of the inverted conical surface portion,
The water sampling pipe is connected to the apex portion of the inverted conical surface portion,
2. The sedimentation evaluation apparatus according to claim 1, wherein the gradient of the inverted truncated cone surface portion is gentler than the gradient of the inverted cone surface portion.
An optimum addition amount calculation device for calculating an optimum addition amount of at least one of an aggregating agent and an aggregation auxiliary agent,
The sedimentation evaluation apparatus according to claim 6, comprising a plurality of containers;
The addition amount of at least one of the flocculant and the flocculant auxiliary added to the raw water in the plurality of containers, and the raw water in each container calculated by the calculation unit (1) the second in the stationary period The amount of change in the number of particles in the particle size range over time, (2) the amount of change in the number of particles in the first particle size range over time in the standing period, and (3) the amount of change in the standing period. An average value of the number of particles in the first particle size range; and (4) the number of particles in the second particle size range in a period from the time when 1 minute or more has elapsed from the start of the rapid stirring to the end of the rapid stirring. And an optimum addition amount calculation unit that calculates an optimum addition amount of at least one of the flocculant and the flocculant auxiliary agent on the basis of the amount of change over time.
It is the optimal addition amount calculation apparatus according to claim 10,
The calculation unit further calculates an average value of the number of particles in the second particle size range measured by the particle number measuring device in the stationary period,
The optimum addition amount calculation unit includes (1) the addition amount of at least one of the flocculant and the flocculant auxiliary added to the raw water in the plurality of containers, and the raw water in each container calculated by the calculation unit. (2) a temporal change in the number of particles in the first particle size range in the stationary period; and (2) a temporal change in the number of particles in the first particle size range in the stationary period. 3) an average value of the number of particles in the first particle size range in the stationary period; and (4) the first value in a period from the time when 1 minute or more has elapsed from the start of the rapid stirring to the end of the rapid stirring. 2 based on the amount of change over time in the number of particles in the particle size range of 2 and (5) the average value of the number of particles in the second particle size range in the stationary period, The optimum addition amount characterized by calculating the optimum addition amount of one Detection device.