JP6334285B2 - Aggregation state detection method, aggregation state control method, aggregation state detection device, and aggregation state control device - Google Patents

Description

  Embodiments described herein relate generally to an aggregation state detection method, an aggregation state control method, an aggregation state detection device, and an aggregation state control device.

  In the fields of water and sewage, wastewater treatment, water supply, etc., various methods have been devised and implemented for purifying water. Water purification is to remove unnecessary solids and dissolved substances in water and those that cannot be discharged to a subsequent process. As a general method, a water tank is installed to retain the water to be treated, and solids are settled and separated by the difference in specific gravity and gravity. In addition to the sedimentation, chemicals such as a coagulant and a flocculant are added. For example, a coagulation sedimentation method in which a solid is coarsened and separated by sedimentation is used. Other examples include membrane separation that filters using porous ceramics and resins, and an activated sludge method that allows microorganisms to eat organic substances.

  Among these, the coagulation precipitation method is widely used because it has a relatively simple configuration of chemical injection, stirring, and precipitation tank, and it is easy to obtain good treated water quality. In the coagulation-precipitation method for water treatment, a coagulant such as PAC (polyaluminum chloride) or sulfated clay is injected into the water to be treated, stirred and mixed in a mixing basin, and the particle size of the aggregate is determined by a flocculator. It is common to promote growth and to separate the agglomerates in the sedimentation basin. The basic configuration is the same for industrial wastewater treatment, etc., but a technique that uses a polymer flocculant in addition to the coagulant to improve the sedimentation rate of the aggregate and to perform high-speed separation is used. There is also.

  In the coagulation sedimentation method, the degree of clarification of treated water, which is the purpose of water treatment, is the concentration of solids to be removed, particle size of solids, surface charge state, water conductivity and pH, water temperature, flocculant It depends on various factors such as the type and number of drugs, injection rate, stirring intensity, stirring time, allowable water area load of the precipitation tank, and the like. Furthermore, among these concentrations, those related to the quality of the water to be treated and the solids in the water to be treated vary over time, so adjust the pH and the injection rate of the drug accordingly and adjust appropriately. It is necessary to control water treatment.

  In view of such a problem, conventionally, in the field of water supply, for example, the formulation of the flocculant injection rate has been performed using turbidity and alkalinity as indexes. In the field of water treatment facilities, it is common to determine the drug injection rate by combining these indicators with the results of an actual agglutination test (jar test) at the beaker scale.

  However, it is not possible to control the aggregation state with high accuracy by itself, and it is not necessarily abundant in specialist knowledge that the operator wants to inject a lot of medicine when the aggregation state deteriorates. For example, there are situations where the amount of drug is not always appropriate.

  Therefore, in recent years, a more advanced method for detecting an aggregate state has been devised, such as measurement of the aggregate formation state using scattered light (Patent Document 1). The scattered light method is a particle concentration measurement technique often used for turbidity measurement, and measures the intensity of light scattered by particles by applying laser light to water. By measuring the scattered light in the agglomerate formation process in a water tank that is stirred for agglomerate formation after the injection of the drug, the formation state of the agglomerate can be known from the concentration of particles in water.

  However, in such a method, since a single numerical value is output as an aggregated value of measurement points within a certain range (a range in which the detector can collect light), the output value is likely to fluctuate and can be measured stably. There is a problem that it is difficult. Furthermore, it is synonymous with measuring the shadow of the aggregate, and there is a problem that it cannot be known at all whether or not the content of the aggregate is good.

JP 2005-241338 A

  An object of this invention is to provide the method of detecting and controlling the aggregate state of an aggregate more accurately.

  The aggregation state detection method of the embodiment includes a step of aggregating solids in water to be treated using a chemical agent to obtain an aggregate including the solids and a gel-like material formed so as to surround the solids, and the aggregation Obtaining a bright field image and a phase difference image of the aggregate by imaging means. Further, image processing is performed on the bright field image and the phase difference image to obtain a difference image between the bright field image and the phase difference image, and based on the difference image, the aggregate in the aggregate Identifying a solid and the gel.

It is a figure which shows schematic structure of the coagulation sedimentation apparatus in embodiment. It is a figure which shows schematic structure of the aggregation state detection apparatus in embodiment. It is a photograph which shows the bright field image and phase contrast image of an aggregate. It is a photograph which shows the image obtained by performing the subtraction process (difference process) of a bright field image and a phase difference image. It is a photograph which shows the image based on the subtraction process (difference process) of the bright-field image and phase difference image of the aggregate obtained when changing the quantity of a chemical | medical agent in three steps. It is a graph which shows the area ratio of the solid substance with respect to the gel-like thing of an aggregate.

(Agglomeration process)
Drawing 1 is a figure showing the schematic structure of the coagulation sedimentation device in an embodiment.
As shown in FIG. 1, the coagulation sedimentation apparatus 10 of the present embodiment forms a storage tank 11 for storing the water to be treated W0 and an aggregate disposed adjacent to the storage tank 11. A first agglomeration tank 12, a second agglomeration tank 13 for coarsening the agglomerates disposed adjacent to the first agglomeration tank 12, and the second agglomeration tank 13. And a sedimentation tank 14 for precipitating the coarsely agglomerated aggregates.

  In addition, a medicine storage tank 15 containing a medicine (flocculating agent) P is disposed via a pump 18 on the upstream side of the first aggregation tank 12. Further, a first stirrer 16 and a second stirrer 17 are disposed in the first aggregating tank 12 and the second aggregating tank 13, respectively.

  The first stirrer 16 is provided with a stirring blade 16A on one end side and a motor 16B on the other end side. As with the first stirrer 16, the second stirrer 17 is provided with a stirring blade 17A on one end side and a motor 17B on the other end side.

Next, a coagulation sedimentation method using the coagulation sedimentation apparatus 10 shown in FIG. 1 will be described.
First, the water to be treated W0 is stored in the storage tank 11, and then the water to be treated W0 is fed into the first aggregating tank 12 using a head difference or a pump (not shown). In the first coagulation tank 12, a predetermined chemical (coagulant, coagulant, etc.) P is supplied from the chemical reservoir 15, and the first agitator 16 is driven to uniformly mix with the water to be treated W 0. As a result, the suspended particles in the water to be treated W0 and solids such as partially dissolved components gather together due to the charge neutralization action and van der Waals force by the chemicals to form the aggregate S1. In addition, the stirring by the first stirrer 16 has an effect of improving the collision probability between the drug and the solid matter or aggregates such as suspended particles while dispersing the drug relatively quickly.

  Further, in order to accelerate the formation rate of aggregates, the pH can be adjusted appropriately by adding acids such as hydrochloric acid and sulfuric acid, and alkalis such as slaked lime and caustic soda.

  Subsequently, the to-be-processed water W0 containing the aggregate S1 in the 1st aggregation tank 12 is sent into the 2nd aggregation tank 13 using a head difference or a pump which is not illustrated. In the second agglomeration tank 13, by driving the second agitator 17, the agglomerates S1 obtained in the first agglomeration tank 12 collide with each other to grow and coarsen the agglomerates S1. Aggregate S2 is obtained.

  Subsequently, the to-be-processed water W0 containing the aggregate S2 in the 2nd aggregation tank 12 is sent to the sedimentation tank 14 using a head difference or a pump which is not illustrated. In the sedimentation tank 14, the coarsely aggregated aggregate S2 is separated by gravity sedimentation, and the water to be treated W0 from which the aggregate S2 has been removed is discharged from the sedimentation tank 14 to the outside as the treated water W1.

(Aggregation state detection device (aggregation state control device))
FIG. 2 is a diagram illustrating a schematic configuration of the aggregation state detection device according to the embodiment.
The agglomeration state detection apparatus 20 shown in FIG. 2 is configured to agglomerate S1 obtained by aggregating solids such as suspended particles in the water to be treated W0 using a chemical in the first agglomeration tank 12. An image processing is performed on the bright field image and the phase difference image, and the camera 22 as an imaging means for obtaining the bright field image and the phase difference image, which will be described below, of the aggregate S1, which is taken out from the tank 12. A computer as a computing means for obtaining a difference image between a field image and a phase difference image, and discriminating the form of the aggregate, the solid matter in the aggregate and the gel-like substance described later based on the difference image 23.

  Note that the aggregation state detection device 20 of the present embodiment includes a support plate 21 for supporting and fixing the aggregate S1 under the lens of the camera 22. It is desirable that the support plate 21 be taken out and fixed while the aggregates are suspended in the liquid by a suction means such as a dropper. Since the aggregate S1 is generally easy to collapse and difficult to fix, it is taken out from the aggregation tank 12 while being suspended in water using a pump or the like, and the aggregate is passed under the lens while passing water using a flow cell. May be.

  Moreover, in this embodiment, although the aggregate S1 obtained in the 1st aggregation tank 12 is selected as an aggregate which detects an aggregation state, the coarse-grained aggregation obtained in the 2nd aggregation tank 13 is selected. The substance S2 may be sufficient, and the aggregate S2 settled in the sedimentation tank 14 may be sufficient.

  Furthermore, by adding a function for controlling the supply amount of the medicine P as described below to the computer 23, the computer 23 functions as an arithmetic control means.

(Aggregation state detection method (aggregation state control method))
Next, an aggregation state detection method (aggregation state control method) using the aggregation state detection device (aggregation state control device) 20 shown in FIG. 2 will be described.

<Form of aggregate>
First, the form of the aggregate will be described.
About the solid substance density | concentration of the treated water W1, it is also the objective of water-treating and it must observe a predetermined level. If the agglomeration state is deteriorated, for example, if the coarsening in the second agglomeration tank 13 is not sufficient, a sufficient sedimentation speed corresponding to the design of the precipitation tank 14 cannot be obtained, and the solids concentration of the treated water W1 is It gets worse easily. The cause is that the concentration of the solids in the water to be treated W0 has fluctuated in the first flocculation tank 12 but the chemical injection conditions cannot be adjusted to an appropriate range.

  It is said that the solid does not aggregate until the concentration of the drug (coagulant, flocculant, etc.) reaches a certain concentration, and this concentration is called the critical aggregation concentration. When the concentration is higher than that, aggregation starts and aggregates start to form, but the state varies depending on the concentration. The purpose of water treatment is to agglomerate and separate solids such as suspended particles and clarify the water. Therefore, the concentration of the purified treatment water obtained by increasing the concentration of the drug is appropriate. It can be said that it is a drug injection amount. If the concentration is lower than this, the amount of drug is relatively insufficient with respect to the amount of suspended particles, finely aggregated particles, that is, solids drift in the water, and the solids concentration in the treated water W1 is high. It becomes a state.

  In addition, when the injection concentration of the drug is increased, the drug gradually becomes excessive, but since the drugs have an action of aggregating, it is possible to obtain clear treated water up to a certain concentration range. it can. When the concentration is further increased, the drugs cannot be aggregated together, and a relatively large number of drugs are in a form of relatively solid solids, so that the aggregate S1 is not coarsened and the aggregate S1. As a result, the solids concentration of the treated water W1 increases.

  Furthermore, sludge increases when chemicals are added to the water to be treated W0. That is, in addition to the amount of solids such as suspended particles, the amount of drug is added as sludge. However, in actuality, sludge increases more than the amount of chemicals. This is because the medicine takes in water in the water to be treated W0. Drugs such as a coagulant and a flocculant are polymers and are characterized by forming a hydrogel. Regardless of whether it is an inorganic coagulant such as PAC or an organic polymer flocculant such as polyacrylamide, it is a polymer that has many hydrophilic groups, regardless of differences in molecular weight, composition, or structure. When agglomerated and solidified, a hydrogel is formed. This hydrogel is formed as a gel-like material so as to surround solids such as suspended particles.

  Therefore, the obtained aggregate S1 is configured to include a solid such as suspended particles and a gel-like material formed so as to surround the solid.

  In addition, the coarse-aggregated aggregate S2 obtained in the second aggregation tank 13 and the sedimentation tank 14 is also obtained by the collision of the aggregates S1 with each other, and has the same configuration as the aggregate S1. .

<Aggregation state detection method (aggregation state control method)>
As shown in FIG. 2, the detection of the aggregation state using the aggregation state detection device 20 is performed by collecting the aggregate S1 from the first aggregation tank 12, placing it on the support plate 21, and supporting and fixing it. . Next, a bright-field image and a phase-contrast image of the aggregate S <b> 1 are taken in the same field by the camera 22 disposed above the support plate 21. For example, a digital camera for a microscope can be used as the camera 22.

FIG. 3 is a photograph showing a bright field image and a phase contrast image of the aggregate S1. As is clear from FIG. 3, the bright field image located on the left side of FIG . 3 (with the left side of the registered figure as the top) makes it easy to observe the solid matter in the aggregate S1, but grasps the outline of the aggregate S1. Lacks contrast. On the other hand, the phase difference image located on the right side of FIG. 3 (with the left side of the registered figure as the top) is suitable for observing a permeable gel-like material existing around the solid matter, and the aggregate S1. Since the whole surface emerges, the outline of the aggregate S1 can be grasped, but it is not suitable for distinguishing solids such as suspended particles from the aggregate S1.

  Therefore, in the present embodiment, the computer 23 performs the above-described subtraction processing (difference processing) of the bright field image and the phase difference image. FIG. 4 is a photograph showing an image obtained by performing a subtraction process (difference process) between the bright field image and the phase difference image. As shown in FIG. 4, the image obtained by the subtraction process (difference process) as described above is the outline of the aggregate S1, the solid matter such as suspended particles, and the gel-like shape present around the solid matter. It can be seen that the object can be identified.

  In view of such knowledge, using kaolin powder, which has been used as a turbidity standard in the water supply field as a solid, and PSI (polysilica iron) flocculant as a drug, the amount of the drug is changed in three stages. Thus, an image based on the subtraction process (difference process) of the bright field image and the phase difference image as shown in FIG. 4 was obtained. In addition, the said powder was put into the 1st aggregation tank 12 by the density | concentration of 100 mg / l.

  FIG. 5 is a photograph showing an image based on the subtraction process (difference process) between the bright field image and the phase difference image of the aggregate S1 obtained when the amount of the drug is changed in three stages.

As shown in the photograph on the left side of FIG. 5 (with the left side of the registered figure as the top) , when the drug was set at 10 mg / l, the amount of drug injected was insufficient with respect to the powder, and a certain amount of the powder Although the agglomerate S1 was formed, a powder that could not be agglomerated remained in the supernatant of the treated water W1.

In addition, as shown in the photograph in the center of FIG. 5 (with the left side of the registered figure as the top) , when the drug is set to 40 mg / l, the drug injection amount is appropriate for the powder, and the agglomeration The treated water W1 after sedimentation of the substance S1 was clear, and almost no powder remained in the supernatant.

Furthermore, as shown in the photograph on the right side of FIG. 5 (with the left side of the registered figure on the top) , when the drug is set to 100 g / l, the injection amount of the drug is excessive with respect to the powder, and the relative Therefore, the ratio of the flocculant in the aggregate S1 is increased. Aggregate S1 is formed and settles, so it looks like a good water treatment at first glance.

  As is clear from FIG. 5, as the amount of the injected drug increases, the drug takes in the water in the water to be treated W0 to form more hydrogel, and around the powder constituting the aggregate S1. It can be seen that more gel-like materials are formed so as to surround the.

  Therefore, in this embodiment, the ratio of the solid substance of the aggregate S1 and the ratio of the gel-like substance are expressed using the area ratio from the image in FIG. FIG. 6 is a graph showing the area ratio of the solid to the gel of the aggregate S1. Each graph in FIG. 6 corresponds to each image in FIG. Further, the graph shown in FIG. 6 shows the average value, the minimum value, and the maximum value in the state where the above-described operation is performed 10 times and 10 types of images as shown in FIG. 5 are obtained.

  The graph shown on the left side of FIG. 6 is the area ratio when the injection amount of the drug is insufficient, as shown in the image on the left side of FIG. 5, and the area ratio of the solid to the gel of the aggregate S1 Is the highest, with an average value of 0.6.

  Further, the graph shown on the right side of FIG. 6 is an area ratio when the injection amount of the drug is excessive as shown in the image on the right side of FIG. 5, and a large amount of gel is formed due to the drug. Therefore, the average value is 0.15.

  Furthermore, the graph shown in the center of FIG. 6 is an area ratio when the injection amount of the medicine is an appropriate amount as shown in the center image of FIG. 5, and the average value is 0.5. Thus, it can be seen that an intermediate value between the above-described case where the injection amount of the drug is insufficient and the case where the injection amount of the drug is excessive is taken.

  Therefore, in view of the above-described results, it can be seen that, for example, an area ratio of 0.4 to 0.55 is an appropriate amount of medicine to be injected. For this reason, when the result obtained as described above is smaller than, for example, an area ratio of 0.4 to 0.55, since the amount of medicine injection is insufficient, the computer 23 functioning also as a calculation control means. For example, a control signal is transmitted to the pump 18 disposed on the downstream side of the medicine injection tank 15 to increase the supply amount of the medicine injected into the medicine injection tank 15 or to start the supply of the medicine. .

  On the other hand, if the result obtained as described above is larger than, for example, an area ratio of 0.4 to 0.55, the amount of medicine injection is excessive. A control signal is transmitted to the pump 18 disposed on the downstream side of the medicine injection tank 15 to reduce the supply amount of the medicine injected into the medicine injection tank 15 or to stop the supply of the medicine.

  If it carries out as mentioned above, supply of a chemical | medical agent can be easily controlled so that formation of the aggregate S1 in the 1st aggregation tank 12 can be performed efficiently and effectively, and the to-be-processed water W0. The solid matter (powder) contained therein can be reduced, and clean treated water W1 containing as little solid matter as possible can be obtained.

  In FIG. 6, the area ratio of the solid to the gel of the aggregate S1 is obtained and graphed, but the area ratio of the gel to the solid of the aggregate S1 is obtained and graphed. May be. In the latter case, the specific value of the area ratio is different from that in the former case. However, the area ratio of the graph corresponding to the central image in FIG. It is an area ratio corresponding to the case.

  In addition, when the control time delay is taken into account due to large water quality fluctuation of the water to be treated, the agglomerate S1 in the first agglomeration tank 12 at an early stage of the agglomeration precipitation process, that is, as described above. It is preferable to collect the image and use it for the image processing and calculation processing as described above. On the other hand, when there is a time allowance for detecting the state of the aggregate with higher accuracy, such as a small change in the quality of the water to be treated, a coarse stage in the second coagulation tank 13 or the precipitation tank 14 is used. It is preferable that the agglomerated aggregate S2 is collected and used for the image processing and arithmetic processing as described above.

  As mentioned above, although several embodiment of this invention was described, these embodiment was posted as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Coagulation sedimentation apparatus 11 Storage tank 12 1st aggregation tank 13 2nd aggregation tank 14 Precipitation tank 15 Drug storage tank 16 1st stirrer 17 2nd stirrer 18 Pump 20 Aggregation state detection apparatus (aggregation state control apparatus)
21 support plate 22 camera 23 computer

Claims (8)

Aggregating a solid in the water to be treated with a chemical to obtain an agglomerate comprising the solid and a gel-like material formed so as to surround the solid;
Obtaining a bright-field image and a phase-contrast image of the aggregate by imaging means;
Performing image processing on the bright field image and the phase difference image to obtain a difference image between the bright field image and the phase difference image;
Identifying the solid and the gel in the aggregate based on the difference image;
A method for detecting an aggregation state, comprising:   The method further comprises the step of calculating the area ratio of the solid substance to the gel substance or the area ratio of the gel substance to the solid substance after identifying the solid substance and the gel substance in the aggregate. The aggregation state detection method according to claim 1, wherein:   The method further comprises determining whether the amount of the drug is excessive or insufficient based on an area ratio of the solid to the gel or a threshold of an area ratio of the gel to the solid. The aggregation state detection method according to claim 2. Aggregating solids in water to be treated with chemicals in a tank to obtain agglomerates including the solids and a gel-like material formed so as to surround the solids;
Taking out the aggregate from the tank and obtaining a bright-field image and a phase-contrast image of the aggregate by imaging means;
Performing image processing on the bright field image and the phase difference image to obtain a difference image between the bright field image and the phase difference image;
Identifying the solid and the gel in the aggregate based on the difference image;
After identifying the solid and the gel in the aggregate, calculating an area ratio of the solid to the gel or an area ratio of the gel to the solid;
When the area ratio exceeds a threshold, it is determined that the amount of the drug is excessive, the supply amount of the drug is decreased or the supply of the drug is stopped, and when the area ratio falls below the threshold, Determining that the amount is insufficient, and increasing the supply amount of the medicine or starting the supply of the medicine; and
A method for controlling the aggregation state, comprising: Obtained solids in the water to be treated is coagulated with drug agents, to obtain a bright field image and the phase contrast images of an aggregate comprising the solid and gel-like material formed so as to surround the solid Imaging means;
Perform image processing on the bright field image and the phase difference image, obtain a difference image between the bright field image and the phase difference image, and based on the difference image, the solid matter in the aggregate and the A computing means for identifying the gel-like material;
An agglomeration state detection apparatus comprising:   The computing means, after identifying the solid and the gel in the aggregate, calculates the area ratio of the solid to the gel or the area ratio of the gel to the solid The aggregating state detection device according to claim 5, wherein the aggregating state detection device is configured to do so. The calculation means determines that the amount of the drug is excessive when the area ratio exceeds a threshold value, and determines that the amount of the drug is insufficient when the area ratio falls below the threshold value. The aggregation state detection apparatus according to claim 6, which is configured. Obtained solids in the water to be treated is coagulated with drug agents, to obtain a bright field image and the phase contrast images of an aggregate comprising the solid and gel-like material formed so as to surround the solid Imaging means;
Perform image processing on the bright field image and the phase difference image, obtain a difference image between the bright field image and the phase difference image, and based on the difference image, the solid matter in the aggregate and the After identifying the gel-like substance, the area ratio of the solid substance to the gel-like substance or the area ratio of the gel-like substance to the solid substance is calculated, and when the area ratio exceeds a threshold, the drug It is determined that the amount of the drug is excessive, the supply amount of the drug is decreased or the supply of the drug is stopped, and when the amount falls below the threshold, the amount of the drug is determined to be insufficient, An arithmetic control means for increasing the supply amount or starting the supply of the medicine;
An agglomerated state control device, comprising:

Images