WO2020213737A1

WO2020213737A1 - Parameter calculation method, separation film property prediction method, and separation membrange operation method

Info

Publication number: WO2020213737A1
Application number: PCT/JP2020/016973
Authority: WO
Inventors: 浩志濱田; 間谷　聖子; 和希羽川
Original assignee: 東レ株式会社
Priority date: 2019-04-19
Filing date: 2020-04-17
Publication date: 2020-10-22
Also published as: JPWO2020213737A1

Abstract

A membrane separation activated sludge method is provided which, for separating raw water into treated water and activated sludge using a separation membrane, involves a sludge imaging step in which the activated sludge is imaged with an optical means to obtain a sludge image, a sludge image processing step in which the image is processed to obtain sludge image information, and a parameter processing step in which a membrane filtration parameter is calculated on the basis of the image information.

Description

Parameter calculation method, separation membrane characteristics prediction method, separation membrane operation method

The present invention relates to a parameter calculation method, a separation membrane characteristic prediction method, and a separation membrane operation method.

The membrane separation method has features such as energy saving space and improvement of filtered water quality, so its use in various fields is expanding. For example, the membrane separation activated sludge method used when treating sewage and industrial wastewater is a solid-liquid separation of activated sludge using a filtration membrane or the like in which biological treatment is performed in a biological reaction tank and immersed in the reaction tank. It is a treatment method to obtain clear treated water.

In such a membrane separation activated sludge method, solids such as the activated sludge itself and impurities in the liquid to be treated flowing into the reaction vessel adhere to the surface of the separation membrane, and the adhered substances cause an increase in membrane filtration resistance. Become. At this time, when the membrane filtration resistance increases, the membrane filtration flow rate decreases when the membrane filtration is performed by applying a constant membrane filtration pressure, and between the membranes when the membrane filtration is performed with the membrane filtration flow rate constant. The differential pressure increases. In the former case, the planned flow rate cannot be secured, and in the latter case, energy for increasing the pressure is required, and at the same time, the burden on the separation membrane increases. Therefore, in the membrane separation activated sludge method, air etc. is diffused by an air diffuser installed at the bottom of the filtration membrane so that the filtration efficiency does not decrease, and the separation membrane is separated by the vibration effect and stirring effect of the separation membrane due to bubbles and ascending current. Filtration is performed while removing the deposits on the film surface.

Even so, when the liquid to be treated is membrane-filtered, the amount of pollutants accumulated on the membrane surface and in the membrane pores increases with the amount of treated water, and there is a problem that the amount and quality of treated water decreases or the membrane filtration pressure rises. It will be. Such an increasing behavior of membrane filtration resistance is greatly affected by the membrane filtration conditions and the state of sludge, and is therefore an important factor for continuous membrane filtration. That is, in order to perform efficient and stable filtration, it is important to monitor the state of activated sludge and find the operating conditions suitable for the state of activated sludge.

In Patent Document 1, after imaging the activated sludge collected from the membrane separation activated sludge tank by optical means, the captured image is processed, and the management parameters obtained from the processed image information are compared with the preset control reference range. A method of determining the operating conditions has been proposed.

In Patent Document 2, the liquid to be filtered is actually membrane-filtered, and parameters are determined from changes in the value of the intermembrane differential pressure, the membrane filtration flux, and the membrane filtration resistance at that time, and the change over time in the membrane filtration resistance. And a prediction method for obtaining the time course of the intermembrane differential pressure has been proposed.

International Publication No. 2018/181618 International Publication No. 2009/054506

In order to determine the optimum operating conditions, it is necessary to quantify the membrane filtration property of the activated sludge from the state of the activated sludge, and to consider the influence of the current activated sludge state and the operating conditions on the membrane filtration resistance. However, in Patent Document 1, although the operating conditions for maintaining the current sludge state can be determined, the membrane filtration property of sludge cannot be quantitatively grasped. Further, in Patent Document 2, a filtration test is mentioned as a method for grasping the membrane filtration property of sludge, but for that purpose, it is necessary to actually perform membrane filtration with a membrane filtration test device, and the state is monitored in-line. That was difficult.
Therefore, an object of the present invention is to provide a method for calculating parameters and a method for predicting separation membrane characteristics in the membrane separation activated sludge method, which can quantify the membrane filterability of activated sludge in-line.

In order to achieve the above object, the present invention has the following configuration.
(1) In the membrane separation activated sludge method in which raw water is separated into treated water and activated sludge by using a separation membrane, a sludge imaging step of imaging active sludge by optical means to obtain a sludge image and the above-mentioned image. A parameter calculation method comprising a sludge image processing step of obtaining sludge image information and a parameter calculation step of calculating a membrane filterability parameter based on the image information.
(2) The membrane filtration parameters are the cake adhesion rate, the cake peeling rate, the cake resistance, the non-peeling cake formation rate, the non-peeling cake resistance, the progress rate of closure of the separation membrane pores, and the resistance due to the closure of the separation membrane pores. The parameter calculation method according to (1), wherein the parameter is related to the calculation of any of the above.
(3) The parameter calculation method according to (1) or (2), wherein the sludge image information is sludge image information in which a solid phase region and an aqueous phase region are distinguished.
(4) The parameter calculation method according to (3), wherein the membrane filtration parameter is calculated under any of the following conditions (a) to (f).
(A) Calculate the membrane filterability parameter from the image information element obtained for the solid phase region (b) Calculate as a combination of a plurality of membrane filterability parameters calculated in (a) above (c) The aqueous phase Calculate the membrane filterability parameter from the image information element obtained for the region (d) Calculate as a combination of the plurality of membrane filterability parameters calculated in (c) above (e) For the solid phase region and the aqueous phase region The membrane filterability parameter is calculated from a plurality of required image information elements (f) Calculated as a combination of the plurality of membrane filterability parameters calculated in the above (a) to (e) (5) The image information element However, the area of the solid phase region, the peripheral length of the solid phase region, the area of the aqueous phase region, the peripheral length of the aqueous phase region, the distance between the solid phase regions, the number of the solid phase regions, and Described in (4), the element selected from the group consisting of the brightness between the solid phase regions is at least one of a total value, a maximum value, a minimum value, an average value, a median value, and a deviation value. Parameter calculation method.
(6) Of the membrane filtration parameters, the parameters related to cake resistance and closure of the separation membrane pores are the total area of the floc region below a certain area surrounded by the aqueous phase region per unit field of view in the image information element. The parameter calculation method according to (5), wherein the parameter calculation method is performed.
(7) The parameter calculation method according to any one of (1) to (6), wherein the sludge image is an image captured at an imaging magnification of 2 times or more and 1000 times or less.
(8) In the membrane separation activated sludge method in which raw water is separated into treated water and activated sludge using a separation membrane, the activated sludge is imaged by optical means to obtain a sludge image, and the sludge imaging step described above. Based on the sludge image processing step of processing the sludge image to obtain sludge image information, the parameter calculation step of calculating the membrane filterability parameter from the correlation obtained in advance based on the sludge image information, and the membrane filterability parameter. A method for predicting separation membrane characteristics, which comprises a time-dependent change prediction step for predicting a time-dependent change in cake membrane filtration resistance or a time-dependent change in intermembrane differential pressure.
(9) The method for predicting separation membrane characteristics according to (8), wherein the change over time is predicted when the membrane filterability parameter deviates from a predetermined reference range or a predetermined rate of change. ..
(10) In the membrane separation activated sludge method in which raw water is separated into treated water and activated sludge using a separation membrane, the activated sludge is imaged by optical means to obtain a sludge image, and the sludge imaging step described above. Based on the sludge image processing step of processing the sludge image to obtain sludge image information, the parameter calculation step of calculating the membrane filterability parameter from the correlation obtained in advance based on the sludge image information, and the membrane filterability parameter. Separation including a time-dependent change prediction step for predicting a time-dependent change in cake membrane filtration resistance or a time-dependent differential pressure, and controlling operating conditions from the membrane filterability parameter or the prediction result of the time-dependent change. How to operate the membrane.
(11) When the prediction result of the membrane filtration parameter or the change over time of the membrane filtration resistance or the change over time of the intermembrane differential pressure deviates from a predetermined reference range or a predetermined rate of change, the operating conditions are changed. The method for operating a separation membrane according to (10), which comprises controlling.
(12) From the prediction result of the change with time, a predicted date in which the membrane filtration resistance or the intermembrane differential pressure deviates from a predetermined reference range is calculated, and the number of days until the predicted date deviates from the predetermined reference range. The method for operating a separation membrane according to (11), wherein the operating conditions are controlled in the case of
(13) The method for operating a separation membrane according to (12), wherein the air volume of air supplied to the separation membrane is controlled when the number of days until the predicted date deviates from a predetermined reference range.
(14) A sludge imaging means, which is a water treatment device that separates raw water into treated water and activated sludge by using a separation film, and obtains a sludge image by imaging the activated sludge by optical means, and the above-mentioned sludge imaging means. A sludge image processing means that processes an image to obtain sludge image information, a parameter calculation means that calculates a membrane filterability parameter based on the image information, and a membrane filtration resistance over time based on the membrane filterability parameter. A water treatment apparatus comprising: a time-dependent change predicting means for predicting a change or a time-dependent change in intermembrane differential pressure.
(15) Membrane separation in the membrane separation active sludge method in which raw water is separated into treated water and activated sludge using a separation membrane. Activated sludge is imaged by an optical means on a computer in order to predict the characteristics of the separation membrane, and a sludge image is obtained. The step of obtaining sludge image information by processing the image, the step of calculating the membrane filterability parameter based on the image information, and the time course of the membrane filtration resistance based on the membrane filterability parameter. Or, a separation membrane property prediction program for performing the step of predicting the time course of the intermembrane differential pressure.
(16) In the membrane separation active sludge method in which raw water is separated into treated water and activated sludge using a separation membrane, the activated sludge is imaged by an optical means on a computer in order to predict the characteristics of the separation membrane, and the sludge image is obtained. The step of obtaining sludge image information by processing the image, the step of calculating the membrane filterability parameter based on the image information, and the time course of the membrane filtration resistance based on the membrane filterability parameter. Or, an operation program of separation membrane characteristics for executing a step of predicting a change in the intermembrane differential pressure with time and a step of controlling operating conditions from the membrane filterability parameter or the prediction result of the change with time.
(17) A computer-readable recording medium on which the separation membrane characteristic prediction program and the separation membrane operation program according to (15) or (16) are recorded.

In the membrane separation active sludge method, the present invention easily and instantly visualizes and quantifies the membrane filtration property of sludge as parameters, so that the time change of membrane filtration resistance, the time change of intermembrane differential pressure, and the membrane filtration flux It is possible to accurately predict the time change or the time change of the membrane filtration flow rate. As a result, operating conditions such as aeration air volume and filtration flow rate that suppress the rapid rise in membrane filtration resistance caused by changes in sludge conditions can be optimized based on predictions made in advance, and stable membrane filtration over a long period of time. Driving can be realized.

FIG. 1 is an example showing the flow of wastewater treatment by the membrane separation activated sludge method. FIG. 2 is an example showing the flow of water to be treated in the activated sludge tank in the membrane separation activated sludge method. FIG. 3 is an example showing an enlarged view of a part of the flat membrane element in the membrane separation activated sludge method. FIG. 4 is a schematic view showing an example of the embodiment of the present invention. FIG. 5 is a captured image showing an example of the form of image processing according to the present invention. FIG. 6 is an example of a flowchart of the prediction method of the present invention. FIG. 7 is another example of the flowchart of the prediction method of the present invention. FIG. 8 is an example showing the flow of wastewater treatment by the membrane separation activated sludge method according to the present invention. FIG. 9 is a schematic view showing an example of the form of the observation jig according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

In the membrane filtration prediction method of the present invention, activated sludge is imaged by optical means to obtain a sludge image, and a membrane filtration parameter is calculated based on the image information obtained by processing the image to obtain the membrane filtration property. Based on the parameters, the change over time in the membrane filtration resistance or the change over time in the intermembrane differential pressure when the membrane filtration is continued while controlling the membrane filtration flow rate as a set value is predicted. Alternatively, the time course of the membrane filtration resistance and / or the time course of the membrane filtration flow rate (flulux) when the membrane filtration is continued while controlling the filtration pressure as a set value is predicted.

1 and 2 outline the flow of general membrane separation activated sludge treatment used in a preferred embodiment of the present invention.
First, the wastewater (raw water) 1 is supplied to the membrane separation activated sludge tank 3 by the raw water supply pump 6, and organic substances and nitrogen in the wastewater are removed and treated by adsorption by the activated sludge and decomposition by microorganisms. The activated sludge is then filtered by the immersion type membrane separation unit 2, and the filtered filtered water 5 is stored in the filtered water tank 4 and then reused or discharged.

Here, the membrane used for the membrane element constituting the immersion type membrane separation unit 2 in the present embodiment is not particularly limited, and may be either a flat membrane or a hollow fiber membrane. FIG. 3 shows an example of a flat membrane element preferably used in this embodiment. The structure of the membrane is not particularly limited, and for example, a flat membrane element structure in which a flat membrane is adhered to both sides of the frame 2d, a flat membrane element structure in which the flat membrane is spirally wound, and a surface on the permeation side are used. A pair of flat membranes having two flat membranes arranged so as to face each other and a water collecting flow path provided between the flat membranes, and a seal that seals between the flat membranes at the peripheral edge of the flat membranes. Any of a flat membrane element structure including a portion and having flexibility, and a hollow fiber membrane element structure in which a plurality of hollow fiber membranes are bundled may be used. The flat membrane preferably used in the present embodiment is composed of a base material 2c and a separation function layer 2b, and between the base material 2c and the separation function layer 2b, a resin and a base material constituting the separation function layer are formed. There may be a layer in which is mixed. The separation functional layer may have a symmetrical structure or an asymmetric structure with respect to the base material.

As a flat membrane, it can be applied to both ultrafiltration membranes and microfiltration membranes. Further, the microfiltration membrane used in the immersion type membrane separation unit 2 in which one or more suitable membranes may be selected and combined according to the size of the substance to be separated is preferably one having a pore size of about 0.01 μm to 10 μm. It is coarser than the ultrafiltration membrane, which is generally separated by molecular sieving, and is usually operated at a reduced operating pressure of 200 kPa or less.

In the present embodiment, when the immersion type membrane separation unit 2 is immersed in the activated sludge tank, a plurality of the immersion type membrane separation units 2 may be arranged side by side or may be stacked in a plurality of stages. When arranging a plurality of the flat membrane elements of the immersion type membrane separation unit, the side surfaces parallel to each other in the direction in which the plurality of dip-type membrane separation units are loaded may be arranged adjacent to each other. Surfaces perpendicular to the direction in which a plurality of membrane elements are loaded may be stacked adjacent to each other in the upper and lower stages.

Here, in the wastewater treatment method by the membrane separation activated sludge method, stable operation means a state in which the filtration pressure does not rise above the preset control range during the operation period and the treated water quality does not deviate from the preset control range. It means that. When the condition of the activated sludge to be filtered deteriorates, the membrane filterability of the activated sludge deteriorates, leading to an increase in the filtration pressure of the membrane. Therefore, it is important to stably maintain and manage the condition of the activated sludge. In addition, it is important to detect changes in the state of activated sludge in the membrane separation activated sludge tank at an early stage and control various wastewater treatment conditions to improve the state of activated sludge before the filtration pressure of the film rises. ..

Activated sludge consists of a solid phase called flocs and aqueous phase suspended matter and other aqueous phases. Flock refers to aggregates composed of solids such as microorganisms, their metabolites, mortality, and other contaminants and precipitates contained in inflow water in activated sludge. The aqueous phase refers to the water content in the voids around and inside the flocs in activated sludge.
The size of the flocs is often about 1 to 1000 μm in diameter, and among them, those having a maximum particle size distribution in 50 to 500 μm are exemplified.

On the other hand, microbial mortality and metabolites may not be taken up by flocs and may exist in the aqueous phase as colloidal or suspended substances. The size thereof is exemplified by a diameter of 50 μm or less, more preferably 10 μm or less, still more preferably 1 μm or less. Distinguish as suspended matter. Typically, in order to distinguish between the solid phase and the aqueous phase, it is preferable to set a predetermined size which is the boundary line of the distinction within the range of 1 to 50 μm in diameter as described above, but it is appropriate depending on the situation of activated sludge. The above-mentioned predetermined size may be set.

In the embodiment of the present invention, the active sludge collected from the membrane-separated active sludge tank is imaged and image-processed by optical means, and the amount of suspended matter in the aqueous phase of the active sludge is a solid phase having a certain area or less existing in the aqueous phase region. In addition to the total area of the region or the ratio of the area of the solid phase region below a certain area to the area of the aqueous phase region, the area of the solid phase region surrounded by the aqueous phase region is included in the area of the aqueous phase region. Any amount that correlates with the ratio of the area of the solid phase region below a certain area to the area of the aqueous phase region may be used, such as when determining the ratio. In particular, when the total amount of activated sludge fluctuates, it is preferable to use the area ratio in order to distinguish it from the fluctuation of the amount of suspended solids in the aqueous phase.

During the filtration operation in the membrane separation active sludge tank, the flocs are separated from the membrane surface by the swirling flow generated by the aeration, and the aqueous phase suspended matter having a size smaller than the pore size of the membrane contained in the aqueous phase and the aqueous phase. Passes through the membrane and is discharged as membrane filtration water. In the present embodiment, the activated sludge in a stable state refers to a state in which biological treatment is smoothly carried out by microorganisms, and the mortality and biotransforms of the generated microorganisms are taken into the flock by being decomposed by another microorganism. This indicates that the amount of suspended solids in the aqueous phase is small. On the other hand, when the balance of biological treatment conditions is lost due to fluctuations in water temperature or water quality, the amount of microbial mortality and metabolites generated increases, decomposition and incorporation into flocs are not in time, and the amount of suspended solids in the aqueous phase increases. Or the flocs are dispersed. As the amount of suspended solids in the aqueous phase increases, as it passes through the membrane, it adheres to and accumulates on the surface or pores of the membrane, making it easier to block the membrane. That is, the membrane filtration property deteriorates. In the present invention, such activated sludge is defined as activated sludge whose condition has deteriorated.

In the present invention, activated sludge is visualized using a microscope which is an optical means, and the image is analyzed to simultaneously acquire information on both the aqueous phase region and the solid phase region, and the state of activated sludge can be immediately obtained. It was found that comprehensive judgment is possible and the degree of clogging when passing through the membrane can be quantified as a membrane filtration parameter. By using the calculated membrane filtration parameter, it is possible to accurately predict the time change of the membrane filtration resistance, the time change of the differential pressure between membranes, the time change of the membrane filtration flux, or the time change of the membrane filtration flow rate. ..

Hereinafter, the details of the preferred embodiment of the present invention will be described.
An embodiment of the present invention will be described with reference to FIG. In the present invention, in the wastewater treatment method by the membrane separation activated sludge method, in order to acquire the filterability parameter of the membrane, the activated sludge is collected from the membrane separation activated sludge tank 3, and the optical means (optical microscope) 41 and the camera (imaging). Means) A sludge imaging step of imaging activated sludge using an imaging means consisting of 43, a sludge image processing step of performing image processing in which conditions are set in advance by the image processing means 42, and a membrane filterability parameter of the current activated sludge are calculated. A step of calculating the parameter to be performed and a step of predicting the time-dependent change of the cake film filtration resistance or the time-dependent change of the intermembrane differential pressure based on the membrane filterability parameter are provided.

The optical means 41 uses a microscope for visualization. The microscope is not particularly limited, and may be a transmission type or an epi-illumination type, and may be a stereoscopic microscope, a phase contrast microscope, a differential interference microscope, a fluorescence microscope, or a transmission type or a scanning type electron microscope. The transmission type phase-contrast microscope is most suitable for the observation target in the present invention and any operability that allows direct observation without pretreatment.

In the sludge imaging step, activated sludge is observed with a microscope 41 and imaged with a camera 43. A certain amount of activated sludge to be observed may be dropped on a slide glass, a cover glass may be placed on the slide glass, and the activated sludge may be placed on the stage of a microscope for observation, and the activated sludge is continuously sent into the gap between two glass plates. It may be liquid and observed as appropriate. Further, a dedicated observation jig 44 described later may be used.

The camera 43 may be a color camera or a monochrome camera, but a color camera is preferable in order to obtain numerical information such as the color tone of activated sludge. A camera equipped with a measurement function is suitable because it can take an image, perform image processing under preset conditions, and immediately quantify it.

In the present embodiment, the flocs are discriminated by those having a diameter of 50 μm or more, and the aqueous phase suspended matter is discriminated by those having a diameter of 50 μm or less. Therefore, the camera 43 need only have a resolution capable of observing and imaging these. In order to recognize and discriminate each of the flocs and aqueous suspended matter and perform image processing to separate them from the noise at the time of imaging, it is preferable to image with 2 pixels × 2 pixels or more, and the spatial resolution in the visual field is high. , 500 nm / pixel or less, more preferably 300 nm / pixel or less.

In the present embodiment, in the optical means 41 and the camera 43, the wavelength selection means for transmitting light rays in the wavelength range of 500 to 800 nm and the phase difference generating means for causing a phase difference when the light rays pass through the imaging target. It is most preferable to have an imaging means for acquiring an image by imaging a transmitted light beam for which a phase difference is generated by the phase difference generating means.

In the sludge image processing step, the captured image is processed under the conditions preset by the image processing means 42. In the captured image, an element extraction means for extracting an image information element in a wavelength range of 500 to 800 nm to create an extracted image, a conversion means for replacing the extracted image with the captured image, and a candidate region with a predetermined threshold value. It is preferable to have a means for creating an extracted image, a means for synthesizing extracted images of a plurality of candidate regions, and a means for quantifying the shape features of each of the extracted regions to obtain a numerical group of image information elements. .. The image information element refers to a feature amount as an image in an image of a flock region or an aqueous phase floating substance, and includes hue, lightness, saturation, number of pixels, chromaticity, and brightness. One or two or more image information elements are extracted from these to create an extracted image, which is further converted into a processed image. Furthermore, in one or more image information elements, threshold values are set for each, extracted images of a plurality of candidate regions are combined, and a plurality of results after determining the threshold values are logically operated to obtain the extracted region. The shape feature is quantified to obtain a numerical group of another image information element.

Further, the image focusing on the component having a wavelength of 500 to 800 nm is an image in the captured image when the imaging target is observed in phase difference using a light source having a wide output wavelength band represented by, for example, an LED light source. A component having a wavelength of 500 to 800 nm may be extracted and obtained at the processing stage.

FIG. 5 shows an example of the form of the extracted image according to this embodiment. When the activated sludge collected from the film-separated activated sludge tank is observed with a microscope in phase contrast, it is observed with the following brightness and color due to the relationship between the refractive index and thickness of the components, and the activated sludge is a solid such as flocs and microorganisms. It is roughly divided into a phase and an aqueous phase, which is a non-flocked region.

The solid phase region 61 has higher brightness and saturation than the aqueous phase, and its color is white or red, yellow, black or brown, although it varies depending on the constituents and the state.
The aqueous phase region 62, which is a non-solid phase region, is imaged with medium brightness as a background, has a gray tint, and has low saturation. In addition, for example, filamentous bacteria and micro-animals are often imaged with medium to low brightness, blue tint, and medium saturation.

The extraction of the solid phase region 61 per unit field of view is not particularly limited, but the captured image is converted into an HSV space composed of three components of hue, saturation, and brightness, and one band, S (saturation). By extracting the degree) component and replacing it with the brightness of the pixels of the display device when displaying the saturation component and obtaining the displayed image, the information of the S (saturation) component of the HSV image is used. Good. As a result, a large contrast is formed between the non-solid phase region and the aqueous phase region 62. Therefore, the binarization treatment is performed according to the high and low saturation to distinguish between the solid phase region and the aqueous phase region. In addition, RGB (red / green / blue) color captured images were decomposed into R, G, and B information, the brightness profile for each component was obtained, and R only, G only, or R and G were combined. It is also preferable to obtain it as an image. The binarization process may be performed by the luminance information or other components or another method.

The threshold value is arbitrarily set while observing the image of activated sludge captured in advance and the brightness distribution, a binarized image is created using the threshold value, the images before and after the processing are compared, and a deviation occurs. In that case, the threshold value is repeatedly corrected to set an appropriate threshold value. A threshold value may be set for the result after multiplying the captured image by various image processing filters. For example, even if a threshold value is set for the result of edge extraction processing represented by a Laplacian filter and the value of the sharpening process for each pixel of the captured image is compared with the threshold value to binarize the captured image. good. Further, the binarized image may be subjected to expansion treatment, contraction treatment, or a treatment in which they are combined to remove noise components from the image.

It is also preferable to obtain information in the target area with high accuracy by performing logical operations on the image information. For example, the total area ratio is calculated from the solid phase region occupying the total area of the unit field image, or the peripheral length of the solid phase region is divided by the area to obtain the roundness to distinguish the solid phase region from other foreign substances. You can do it. These may be arbitrarily calculated manually, or may be automatically calculated using preset calculation software.

In the parameter calculation step, an image information element is acquired as image information in at least one of the solid phase region and the aqueous phase region distinguished by the image processing means 42, and the image information element is used to obtain at least one of the following. Calculate under the above conditions and calculate the membrane filterability parameter.
(A) The membrane filterability parameter is calculated from the image information element obtained for the solid phase region (b) Calculated as a combination of a plurality of membrane filterability parameters calculated in the above (a) (c) The aqueous phase The membrane filterability parameter is calculated from the image information element obtained for the region (d) Calculated as a combination of the plurality of the membrane filterability parameters calculated in the above (c) (e) About the solid phase region and the aqueous phase region. The membrane filterability parameter is calculated from the required plurality of image information elements (f) The membrane filterability parameter is calculated as a combination of the plurality of membrane filterability parameters calculated in the above (a) to (e).
Here, the membrane filterability parameter is an index showing the membrane filterability of activated sludge, and is larger than the activated sludge adhering to the membrane surface called cake and the pore diameter entering the pores of the membrane called pore blockage. Parameters related to the adhesion rate and peeling rate of constituents in small activated sludge, resistance to the amount of adhesion, and the like can be mentioned. Specifically, any one of the cake adhesion rate, the cake peeling rate, the cake resistance, the non-peeling cake forming rate, the non-peeling cake resistance, the progress rate of the closure of the separation membrane pores, and the resistance due to the closure of the separation membrane pores. Parameters related to the calculation can be mentioned, but the parameters are not particularly limited.

As a result of diligent studies, the present inventor found that there is a correlation between the membrane filtration property parameter and the image information element, and made it possible to calculate the membrane filtration property parameter from the image information element. Among the membrane filtration parameters, the membrane filtration parameters related to the calculation of cake resistance and the progress rate of closure of the separation membrane pores are, in particular, the total of the floc regions below a certain area surrounded by the aqueous phase region per unit field of view. It has been clarified that it has a strong correlation with the area, and it is preferable to calculate using this image information element.

The image information element includes the area of the solid phase region, the peripheral length of the solid phase region, the area of the aqueous phase region, the peripheral length of the aqueous phase region, the distance between the floc regions, and the space between the solid phase regions. Examples include the total value, the maximum value, the minimum value, the average value, the median value, or the deviation value for the elements selected from the group consisting of the number and the brightness between the solid phase regions.

Examples of the inter-region distance include the distance between the centers of gravity of each region in the flock, the distance between the regions and the closest portion of the regions, and the like. Further, the present invention is characterized in that the image information element is used for calculation under at least one of the above conditions (a) to (d), and another image information element is calculated. The other image information element is not particularly limited, and examples thereof include the following.
(I) Total area of solid phase region and / or total area of aqueous phase region (ii) Total area ratio of solid phase region to aqueous phase region (iii) Number of solid phase region and / or aqueous phase region (iv) Solid phase region and / Or brightness of aqueous phase region (v) solid phase region and / or circumference of aqueous phase region (vi) area of solid phase region below a certain area surrounded by aqueous phase region or constant surrounded by aqueous phase region Area ratio of the area of the solid phase region below the area to the entire aqueous phase region or the entire solid phase region
(Vii) Area ratio of the area of the aqueous phase region below a certain area surrounded by the solid phase region or the area of the aqueous phase region below a certain area surrounded by the solid phase region to the entire solid phase region or the entire aqueous phase region (vii) viii) Area ratio of the area of the solid phase region of constant color tone or less than constant brightness or the area of the solid phase region of constant color tone or less than constant brightness to the entire aqueous phase region or the entire floc region (ix) Water of constant color tone or less than constant brightness Area ratio of the area of the phase region or the area of the aqueous phase region with a certain color tone or less than a certain brightness to the solid phase region or the aqueous phase region

Specifically, for the brightness of the (iv) solid phase region or the aqueous phase region, it is preferable to use the brightness which is an image processing element individually obtained in the (a) solid phase region and / or the aqueous phase region.

(I) Total area of solid phase region or total area of aqueous phase region, (iii) Number of solid phase regions or number of aqueous phase regions, (v) Peripheral length of solid phase region or peripheral length of aqueous phase region are (b) ) It is preferable to combine at least two or more other image information elements calculated from the image processing elements individually obtained in the solid phase region or the aqueous phase region for each region.

(Ii) The total area ratio of the solid phase region and the aqueous phase region is preferably calculated by combining at least two or more total area values individually obtained in (c) the solid phase region or the aqueous phase region. At this time, the calculation is included in the area of the solid phase region surrounded by the aqueous phase region. In the present embodiment, when it is said that "the ratio of the total area of the solid phase region having a certain area or less surrounded by the aqueous phase region is used", the area of the solid phase region having a certain area or less is relative to the area of the aqueous phase region. In addition to the ratio, when the area of the solid phase region surrounded by the aqueous phase region is included in the area of the aqueous phase region to obtain the ratio, the area of the solid phase region less than a certain area is relative to the area of the aqueous phase region. Any amount that correlates with the proportion may be used. When calculating the ratio, the ratio of each region may be calculated by using the number of regions, the average or total brightness in each region, and the like in addition to the area of the region.

(Vi) Area of solid phase region below a certain area surrounded by the aqueous phase region or area ratio to the aqueous phase region or solid phase region, (vii) Area of the aqueous phase region below a certain area surrounded by the solid phase region Or area ratio to solid phase region or aqueous phase region, (viii) area of solid phase region or water phase region or solid phase region with constant color tone or less than constant brightness, (ix) water with constant color tone or less than constant brightness The area of the phase region or the area ratio to the solid phase region or the aqueous phase region is calculated by combining at least two or more of the values calculated in (a) to (c) of (d), and depends on an arbitrarily set threshold value. It is preferable to classify by.

(Vi) The method of calculating the area of the solid phase region having a certain area or less surrounded by the aqueous phase region or the area ratio to the aqueous phase region or the solid phase region is specifically to discriminate between the aqueous phase region and the solid phase region. After that, the solid phase region with a certain area or less surrounded by the aqueous phase region is determined, and finally, the total area of the aqueous phase region and the solid phase region with a certain area or less surrounded by the aqueous phase region is calculated. An example is a method of calculating the solid phase region area ratio of a certain area or less surrounded by the aqueous phase region to the area of the aqueous phase region. Here, when calculating the area ratio of the solid phase region, the total area of the solid phase region within a certain area surrounded by the aqueous phase region may or may not be included in the area of the aqueous phase region as the denominator. It may or may not be included in the area of the solid phase region. If the area of the solid phase region or the aqueous phase region is less than a certain area surrounded by the aqueous phase region, the area of each region calculated as described above may be used as it is.

(Vii) The method of calculating the area of the aqueous phase region surrounded by the solid phase region or less than a certain area or the area ratio to the solid phase region or the aqueous phase region is also the same as in (vi), the aqueous phase region and the floc region. After determining, determine the aqueous phase region with a certain area or less surrounded by the solid phase region, and finally calculate the total area of the solid phase region and the aqueous phase region with a certain area or less surrounded by the solid phase region. Then, a method of calculating the ratio of the area of the aqueous phase region to a certain area surrounded by the solid phase region to the area of the solid phase region is exemplified. For (viii) and (ix), it is preferable to calculate using the information of brightness and color tone instead of the area in the same procedure as in (vi) and (vii).

Regarding the total area of the solid phase region and the total area of the aqueous phase region showing (i) and the total area of the low-intensity floc region which is an example of (ix), the largest solid phase region or the largest aqueous phase region other than the total area. Maximum area indicating the area of, minimum area indicating the area of the smallest solid phase region or the smallest aqueous phase region, average area in each region of the solid phase or aqueous phase, standard deviation of the area in each region of the solid phase or aqueous phase May be calculated. Regarding the solid phase region average brightness and the aqueous phase region average brightness, which are examples of (iv), the brightness, maximum brightness, minimum brightness, and deviation brightness for each RGB (red, green, blue) may be calculated, or ( Regarding the solid phase region peripheral length and the aqueous phase region peripheral length, which are examples of v), the maximum peripheral length, the minimum peripheral length, the average peripheral length, and the peripheral length deviation may be calculated. According to the present embodiment, a calculated value or a calculated value of at least one of the area, the circumference, the number, and the distance between the regions obtained from the image information in at least one of the solid phase region and the aqueous phase region. The amount of change over time can be calculated immediately.

Next, a time-dependent change prediction step for predicting the time-dependent change in membrane filtration resistance, the time-dependent change in intermembrane differential pressure, or the membrane filtration flow rate (flulux) based on the membrane filtration property parameter will be described. In the membrane filtration prediction method of the present invention, the time course of the membrane filtration resistance or the time course of the intermembrane differential pressure when the membrane filtration is continued while controlling the membrane filtration flow rate as a set value is predicted. Alternatively, when the membrane filtration is continued while controlling the differential pressure between the membranes as a set value, the change with time of the membrane filtration resistance or the change with time of the membrane filtration flow rate (flux) is predicted.

Here, the intermembrane differential pressure is a pressure difference between the filtered liquid side and the permeated liquid side of the separation membrane, and as a means for generating this, for example, a method of pressurizing the filtered liquid side with a pump, a pump. There are a method of sucking from the permeate side and a method of utilizing the head difference between the permeate side and the permeate side. The intermembrane differential pressure can also be measured as the difference between the pressure measurement value on the filtered liquid side and the pressure measurement value on the permeate side of the separation membrane, and at this time, it is generated by a hydraulic flow. It is preferable to measure or calculate the pressure loss and subtract the pressure loss from the difference between the pressure measurement value on the filtered liquid side and the pressure measurement value on the permeate side of the separation membrane. The membrane filtration flow rate is the flow rate of the membrane filtration solution, and the membrane filtration flux is the membrane filtration flow rate per unit area of the separation membrane.

Continuing membrane filtration while controlling the membrane filtration flow rate as a set value, or continuing membrane filtration while controlling the intermembrane differential pressure as a set value means that the membrane filtration flow rate or the intermembrane differential pressure is set in advance. It is to control the value. In addition to the method of controlling the membrane filtration flow rate and the intermembrane differential pressure to be constant, the method of stopping the filtration periodically or intermittently, and the membrane filtration flow rate and the intermembrane differential pressure are continuously controlled. Alternatively, it also includes the case where the set value is changed over time, such as a method of changing it intermittently. As a method of continuing membrane filtration while controlling the membrane filtration flow rate as a set value, a suction pump or the like is installed on the membrane permeation liquid side of the separation membrane to acquire the membrane filtration liquid, and the suction pump is controlled by the flow inverter. The method etc. can be mentioned. In addition, as a method of continuing membrane filtration while controlling the differential pressure between membranes as a set value, the pressure required for membrane filtration is determined by a method of pressurizing the side to be filtered of the separation membrane or a method of utilizing the water head difference. In addition, a method of controlling this pressure and the like can be mentioned.

The membrane filtration resistance is a resistance generated when the liquid to be filtered is filtered by a membrane, and is generally defined by the equation (1).

Here, ΔP is the intermembrane differential pressure [Pa], μ is the viscosity of the membrane filtration solution [Pa · s], R is the membrane filtration resistance [1 / m], and J is the membrane filtration flux [m / s]. ..

Here, μ may directly measure the viscosity of the membrane filtration solution, but since the membrane filtration solution is activated sludge in the membrane separation activated sludge method, it may be converted from the temperature according to Eq. (2).

Here, F = 0.01257187, B = −0.005806436, C = 0.001130911, D = −0.000005723952, and T is the absolute temperature [K]. That is, if the temperature in degrees Celsius is σ [° C.], it is expressed as T = σ + 273.15.

In addition, the prediction is a numerical value that becomes an output (time of membrane filtration resistance, etc.) by performing calculations and calculations using numerical values that are inputs (time series values of membrane filtration flow rate, time series values of intermembrane differential pressure, etc.). It is to output the change prediction value etc.).

Further, in the membrane filtration prediction method of the present invention, when the membrane filtration flow rate (fluctuation) is controlled to a set value and the membrane filtration is continued, at least the membrane filtration flow rate (flow) is used as a numerical value for the membrane filtration prediction calculation. When continuing membrane filtration while controlling the differential pressure between membranes to the set value using the set value of (fluctuation), the initial value of membrane filtration resistance, and the active sludge concentration (MLSS), the membrane filtration prediction calculation is performed. At least the set value of the intermembrane differential pressure, the initial value of the membrane filtration resistance, and the MLSS are used as the numerical values for this purpose.

Here, the initial value of the membrane filtration resistance is the membrane filtration resistance value at the start of membrane filtration, the membrane filtration resistance value when pure water is permeated through the separation membrane, the membrane filtration resistance value after cleaning the separation membrane, and the like. May be an actually measured value, or a virtual value based on the type of separation membrane may be used.

MLSS may be an actual measurement value or a virtual value. In addition, the time change of MLSS of activated sludge may be predicted using an existing simulation model such as the IWA activated sludge model.

The set value of the membrane filtration flow rate (flulux) is a set value of the membrane filtration flow rate or the membrane filtration flux, which may be an actual measurement value or a virtual value, and a constant value that changes continuously or intermittently. May be. Further, the set value of the intermembrane differential pressure may be an actually measured value or a virtual value, may be a constant value, or may be a value that changes continuously or intermittently.

Further, in the membrane filtration prediction method of the present invention, when the membrane filtration is continued while controlling the membrane filtration flow rate to a set value, at least one of the calculation steps 1a and the calculation steps 1b and 1c described later will be performed. By performing the above and calculation step 2 and / or calculation step 3, the membrane filtration resistance value and / or the intermembrane differential pressure value at an arbitrary time can be obtained, and the membrane filtration while controlling the intermembrane differential pressure to the set value. At least one of the calculation steps 1a and 1b and the calculation step 1c, which will be described later, and the calculation step 2 and / or the calculation step 4 are performed to perform membrane filtration at an arbitrary time. Obtain the resistance value and / or the membrane filtration flow rate (fluctuation) value.

That is, it means that there are the following nine configurations of the calculation steps of the membrane filtration prediction when the membrane filtration flow rate is controlled to the set value and the membrane filtration is continued.
(A1) Calculation step 1a, calculation step 1b, calculation step 2 and calculation step 3 described later.
(A2) Calculation step 1a, calculation step 1c, calculation step 2 and calculation step 3 described later.
(A3) Calculation step 1a, calculation step 1b, calculation step 1c, calculation step 2 and calculation step 3 described later.
(B1) Calculation step 1a, calculation step 1b and calculation step 2 described later.
(B2) Calculation step 1a, calculation step 1c and calculation step 2 described later.
(B3) Calculation step 1a, calculation step 1b, calculation step 1c and calculation step 2 described later.
(C1) Calculation step 1a, calculation step 1b and calculation step 3 described later.
(C2) Calculation step 1a, calculation step 1c, and calculation step 3 described later.
(C3) Calculation step 1a, calculation step 1b, calculation step 1c and calculation step 3 described later.

Here, in the case of (a3) (see FIG. 6), the membrane filtration resistance value and the intermembrane differential pressure value at an arbitrary time can be obtained. In the case of (b3), the membrane filtration resistance value at an arbitrary time can be obtained. Further, in the case of (c3), the intermembrane differential pressure value at an arbitrary time can be obtained.

Similarly, it means that there are the following nine configurations of the calculation steps of the membrane filtration prediction when the membrane filtration is continued while controlling the differential pressure between the membranes to the set value.
(D1) Calculation step 1a, calculation step 1b, calculation step 2 and calculation step 4 described later.
(D2) Calculation step 1a, calculation step 1c, calculation step 2 and calculation step 4 described later.
(D3) Calculation step 1a, calculation step 1b, calculation step 1c, calculation step 2 and calculation step 4 described later.
(E1) Calculation step 1a, calculation step 1b and calculation step 2 described later.
(E2) Calculation step 1a, calculation step 1c and calculation step 2 described later.
(E3) Calculation step 1a, calculation step 1b, calculation step 1c and calculation step 2 described later.
(F1) Calculation step 1a, calculation step 1b and calculation step 4 described later.
(F2) Calculation step 1a, calculation step 1c, and calculation step 4 described later.
(F3) Calculation step 1a, calculation step 1b, calculation step 1c and calculation step 4 described later.

Here, in the case of (d3) (see FIG. 7), the membrane filtration resistance value and the membrane filtration flow rate (flux) value at an arbitrary time can be obtained. In the case of (e3), the membrane filtration resistance value at an arbitrary time can be obtained. Further, in the case of (f3), the membrane filtration flow rate (flux) value at an arbitrary time can be obtained.

Here, in the calculation step 1a, the amount of activated sludge (cake) adhering to the surface of the separation membrane is calculated at an arbitrary time.

Here, the calculation step 1a is a calculation step for calculating the amount of change in the amount of cake adhering to the separation membrane surface within a predetermined time, and the calculation formula in the calculation step 1a is that the cake adheres to the separation membrane surface. The term of the rate of adhesion and the term of the rate at which the cake adhering to the surface of the separation membrane peels off from the surface of the separation membrane are included, and the rate of adhering to the surface of the separation membrane is the intermembrane differential pressure value or the membrane filtration flow rate (flow). The bunch) value, the amount of cake and / or the membrane detergency value, and the rate of peeling from the separation membrane surface are separated from the intermembrane differential pressure value or the membrane filtration flow rate (fluctuation) value. It is preferable to calculate using the amount of cake adhering to the film surface and / or the pressure density of the cake. This makes it possible to accurately predict the amount of cake adhering to the surface of the separation membrane at an arbitrary time.

Here, the "consolidation density of the cake adhering to the surface of the separation membrane" is the degree of consolidation by the pressure applied to the cake adhering to the surface of the separation membrane. By calculating the amount of cake adhering to the surface of the separation membrane using this pressure density, the amount of cake adhering to the surface of the separation membrane can be predicted more accurately.

Also, if the cake is sufficiently compacted, the cake adhering to the separation membrane surface will not be peeled off from the separation membrane surface by cleaning with aeration. This fully compacted cake is defined as a non-peelable cake, and the amount of cake adhering to the separation membrane surface can be accurately predicted by using the cake and the non-peelable cake instead of the pressure density.

Further, it is more preferable that the formula for determining the rate at which the cake adhering to the separation membrane surface is peeled off from the membrane surface includes a term based on the membrane detergency value. Here, the membrane detergency is a stress for peeling off a substance adhering to the separation membrane surface, and the value of the membrane detergency is the value of the shearing force generated on the membrane surface and the filtration of the membrane surface. The value of the flow velocity of the liquid, the value calculated based on the shearing force and the flow velocity, or the power value of the cleaning means (the power value of the cleaning means is, for example, the cleaning of the separation membrane is exposed from the lower part of the separation membrane. It is preferable to use a value calculated based on the air volume, the output value of the air blower, etc.), and the value of the membrane detergency is the result of the actual membrane filtration test. It may be calculated / estimated from. This makes it possible to add an element that does not depend on the performance of the separation membrane, such as aeration, as a factor that determines the rate at which the cake adhering to the surface of the separation membrane separates from the surface of the separation membrane. It becomes easier to reflect the operating conditions.

As mathematical formulas satisfying such conditions, for example, there are the following formulas (3) to (5), and in the present invention, it is recommended to follow the formulas (3) to (5). However, the scope of the present invention is not limited to the equations (3) to (5).

However, (1-Kτ1 · τ) ≧ 0 and (τ−Kτ2 · ΔP) ≧ 0.

Here, Xc is the amount of cake attached to the surface of the separation membrane per unit membrane area [gC / m ² ], t is the time [s], X is the MLSS [gC / m ³ ] of the membrane separation tank, and J is the membrane filtration. Flow flux [m / d], Kτ1 is the membrane cleaning power inhibition coefficient [-], γ is the membrane separation coefficient [1 / m / s], τ is the membrane cleaning power value [-], and Kτ2 is the cake friction coefficient [1 /]. Pa] and ΔP are the differential pressure between membranes [Pa], η is the inverse of the density of active sludge [m ³ / gC], Dmax is the maximum pressure density [-] (usually 1), and D is the pressure density [-]. ], Xc, res are the amount of cake to be peeled [gC / m ² ]. Further, "gC" represents the carbon weight. Here, the first term on the right side of the equations (3) to (5) indicates the rate at which the cake adheres to the surface of the separation membrane, and the second term indicates the rate at which the cake separates from the surface of the separation membrane. Further, as described later, when the membrane detergency value τ is expressed as a function of the aeration air volume and the output value of the aeration blower, by substituting the function into τ, equations (3) to (5) can be obtained. It is possible to convert to a formula related to the aeration air volume and the output value of the aeration blower instead of the membrane detergency value.

Further, as described above, when the amount of change in the cake adhering to the surface of the separation membrane is based on a calculation formula expressed as the difference between the speed at which the cake adheres to the separation membrane and the speed at which the cake peels off, the separation membrane is used. It can be expressed as a differential equation related to the amount of attached cake, and at that time, there are Euler method, Runge-Kutta method, Runge-Kutta-Gill (RKG) method, etc. as an integration method for solving this differential equation.

Further, in the calculation step 1b, the amount of sludge-derived substance (pore blockage amount) existing in the separation membrane pores at an arbitrary time is calculated.

Here, the calculation step 1b is a calculation step for calculating the amount of change in the pore closure amount within a predetermined time, and the value of the change amount is the intermembrane differential pressure value and / or the membrane filtration flow rate (flulux). It is preferable to calculate based on the value of the amount of cake adhering to the surface of the separation membrane and / or the amount of pore closure. This makes it possible to accurately predict the amount of pore blockage at an arbitrary time.

As mathematical formulas satisfying such conditions, for example, there are the following formulas (6) to (9), and in the present invention, it is recommended to follow the formulas (6) to (9). However, the scope of the present invention is not limited to the equations (6) to (9).

Here, Xf is the pore closure amount [gC / m ² ], ψ is the mass transfer rate coefficient [gC / m ² / Pa / s] into the separation membrane pores, and ε is the substance into the separation membrane pores. The transfer inhibition coefficient [m ⁴ / gC ² ], Kf is also the mass transfer inhibition coefficient into the separation membrane pores [gC ^2/3 / m ^4/3 ], and λ is the pore closure rate coefficient [s ^m-1 · gC. ^1-b / m ^{2 + m-2b} ], m is a pore-blocking flux-dependent coefficient [-], and b is a pore-blocking cake-dependent coefficient [-].

Further, in the calculation step 1c, the pressure density of the cake adhering to the surface of the separation membrane is calculated at an arbitrary time.

Here, the calculation formula in the calculation step 1c is a calculation step for calculating the amount of change in the pressure density of the cake adhering to the surface of the separation membrane within a predetermined time, and the value of the amount of change is applied to the surface of the separation membrane. It is preferably calculated based on the pressure applied to the attached cake and / or the value of the pressure density of the cake attached to the separation membrane. This makes it possible to accurately predict the pressure density of the cake adhering to the surface of the separation membrane at an arbitrary time. Here, as the pressure applied to the cake adhering to the surface of the separation membrane, the pressure value derived from the cake may be used, or the differential pressure value between the membranes may be used. Further, instead of the compaction density of the cake, the non-peelable cake may be used to express the consolidation.

As a mathematical formula satisfying such a condition, for example, there is the following formula (10) or formula (11), and in the present invention, it is recommended to follow the formula (10) or (11). However, the scope of the present invention is not limited to the equation (10) or the equation (11).

Here, D is the consolidation density [-], k1 is the consolidation rate coefficient [1 / (Pa / s)], Dmax is the maximum consolidation density [-] (usually 1), and ΔPc is the cake pressure value [ Pa] and k are non-peeling cake formation rate coefficients [1 / Pa / s], and l is a non-peeling cake pressure dependence coefficient [−].

Further, in the calculation step 2, the amount of cake adhering to the separation membrane obtained in the calculation step 1a and / or the amount of pore clogging obtained in the calculation step 1b and / or adhering to the separation membrane obtained in the calculation step 1c. The membrane filtration resistance value at an arbitrary time is calculated using the pressure density of the existing cake or the amount of non-peelable cake.

Here, in the calculation step 2, the membrane filtration resistance value at an arbitrary time is calculated based on the value of the pressure applied to the cake adhering to the surface of the separation membrane, and / or 1 of the pore closure amount. It is preferable to include a higher-order equation of ~ quadratic equation. As a result, the membrane filtration resistance value at an arbitrary time can be predicted more accurately. Here, as the pressure applied to the cake adhering to the surface of the separation membrane, the pressure value derived from the cake adhering to the surface of the separation membrane may be used, or the differential pressure value between the membranes may be used.

As mathematical formulas satisfying such conditions, for example, there are the following formulas (12) to (14), and in the present invention, it is recommended to follow the formulas (12) to (14). However, the scope of the present invention is not limited to the equations (12) to (14).

Here, Rc is the cake-derived membrane filtration resistance [1 / m] attached to the surface of the separation membrane, α is the cake resistance coefficient [m / gC], and a is the cake pressure dependence coefficient [m / gC / Pa]. Rf is the membrane filtration resistance derived from pore occlusion [1 / m], β is the pore occlusion filtration resistance coefficient [m ² / gC ^1.5 ], R is the membrane filtration resistance [1 / m], and Rm is the membrane filtration resistance. Is the initial value [1 / m] of.

Further, it is defined that the cakes adhering to the surface of the separation membrane form a hierarchical structure, and it is preferable that the calculation step 1c includes the following calculation steps 1c-1 and 1c-2.
(Calculation Step 1c-1) Based on the amount of cakes adhering to the separation membrane obtained in the calculation step 1a, the number n of cake layers adhering to the surface of the separation membrane at an arbitrary time is calculated.
(Calculation step 1c-2) At an arbitrary time, the i-th layer adhering to the surface of the separation membrane (where i is an arbitrary natural number from 1 to n, the first layer is the closest to the separation membrane, and the first layer. The pressure density of the cake of (n layer is the farthest from the separation membrane) is calculated.

As a result, the amount of cake adhering to the surface of the separation membrane and the membrane filtration resistance value can be predicted more accurately.

Here, the calculation step 1a is a calculation step for calculating the amount of change in the amount of cake adhering to the separation membrane surface within a predetermined time, and the calculation formula in the calculation step 1a is that the cake adheres to the separation membrane surface. The term of the rate of adhesion and the term of the rate at which the cake adhering to the surface of the separation membrane peels off from the surface of the separation membrane are included, and the rate of adhering to the surface of the separation membrane is the intermembrane differential pressure value or the membrane filtration flow rate (flow). The bunch) value, the amount of cake and / or the membrane detergency value, and the rate of peeling from the separation membrane surface are separated from the intermembrane differential pressure value or the membrane filtration flow rate (fluctuation) value. It is preferable to calculate using the amount of cake of the first layer to the nth layer adhering to the film surface and / or the pressure density of the cake of the first layer to the nth layer. This makes it possible to accurately predict the amount of cake adhering to the surface of the separation membrane at an arbitrary time.

Further, in the calculation step 1a, the formula for obtaining the speed at which the cake adhering to the separation membrane surface is peeled off from the separation membrane surface is a quadratic of the cake amount of the first layer to the nth layer adhering to the separation membrane surface. It is more preferable to include the above terms of higher-order functions. Thereby, the amount of cake adhering to the surface of the separation membrane at an arbitrary time can be predicted more accurately.

Formulas that satisfy such conditions include, for example, the following formulas (15) to (17), and in the present invention, it is recommended to follow the formulas (15) to (17). However, the scope of the present invention is not limited to the equations (15) to (17).

Here, n is the number of layers of the cake attached to the separation membrane surface [-], Di is the pressure density of the cake of the i-th layer attached to the separation membrane surface [-], and Xc and i are the separation membrane surface. It is the amount of cake [gC / m ² ] per layer of cake adhering to.

Further, in the calculation step 1c-2, the pressure density of the cake of the i-th layer adhering to the surface of the separation membrane is calculated at an arbitrary time.

Here, the calculation formula in the calculation step 1c includes a calculation step of calculating the amount of change in the pressure density of the cake of the layer i adhering to the surface of the separation membrane within a predetermined time, and the value of the amount of change is separated. It is preferably calculated based on the pressure applied to the cake adhering to the membrane surface and / or the pressure density of the cake of layer i adhering to the separation membrane. As a result, the pressure density of the cake of the i-th layer adhering to the surface of the separation membrane can be predicted more accurately. Here, as the pressure applied to the cake adhering to the surface of the separation membrane, the pressure value derived from the cake adhering to the surface of the separation membrane may be used, or the differential pressure value between the membranes may be used.

As a mathematical formula satisfying such a condition, for example, there is the following formula (18), and in the present invention, it is recommended to follow the formula (18). However, the scope of the present invention is not limited to the equation (18).

Further, it is preferable that the calculation step 2 replaces the following calculation step 2'. As a result, the membrane filtration resistance value at an arbitrary time can be predicted more accurately.
(Calculation step 2') The amount of pore closure determined in calculation step 1b, the amount of cake of layer i adhering to the surface of the separation membrane, and / or adhering to the surface of the separation membrane determined in calculation step 1c. The membrane filtration resistance value at time t + Δt is calculated based on the pressure density of the cake of the i-th layer.

Examples of mathematical formulas satisfying such conditions include the following formulas (19) to (21), and in the present invention, it is recommended to follow the formulas (19) to (21). However, the scope of the present invention is not limited to the equations (19) to (21).

Here, k2 is a consolidation effect constant [−].

Further, in the calculation step 3, the amount of cake adhering to the separation membrane obtained in the calculation step 1a and / or the amount of pore clogging obtained in the calculation step 1b and / or adhering to the separation membrane obtained in the calculation step 1c. The intermembrane differential pressure value at an arbitrary time is calculated by using the pressure density of the cake, or by using the membrane filtration resistance value obtained in the calculation step 2 or the calculation step 2'.

Here, when the membrane filtration prediction is composed of the above (c) (that is, calculation step 1a and / or calculation step 1b and / or calculation step 1c and calculation step 3), it adheres to the separation membrane obtained in calculation step 1a. Intermembrane differential pressure at any time using the amount of cake and / or the amount of pore closure determined in calculation step 1b and / or the pressure density of the cake adhering to the separation membrane determined in calculation step 1c. Calculate the value. As a method for this, for example, the equations (19) and (20) may be substituted into the equation (21), and then the equation substituted into the equation (1) may be used. Further, when the membrane filtration prediction is composed of the above (a) (that is, calculation step 1a and / or calculation step 1b and / or calculation step 1c and calculation step 2 and calculation step 3), the membrane obtained in calculation step 2 is obtained. The filtration resistance value is used to calculate the intermembrane differential pressure value at an arbitrary time. As the method, it is preferable to calculate using the above formula (1) or a mathematical formula based on the above formula (1).

Further, in the calculation step 4, the amount of cake adhering to the separation membrane obtained in the calculation step 1a and / or the amount of the cake existing in the pores of the separation membrane obtained in the calculation step 1b and / or in the calculation step 1c. Membrane filtration flow rate (flux) at any time using the pressure density of the amount of cake adhering to the obtained separation membrane, or using the membrane filtration resistance value obtained in calculation step 2 or calculation step 2'. Calculate the value.

Here, when the membrane filtration prediction is composed of the above (f) (that is, calculation step 1a and / or calculation step 1b and / or calculation step 1c and calculation step 4), the separation membrane obtained in calculation step 1a is used. Membrane filtration at any time using the amount of cake adhering and / or the pore blockage value determined in calculation step 1b and / or the pressure density of the cake adhering to the separation membrane determined in calculation step 1c. Calculate the flow rate (flux) value. As a method for this, for example, the equations (17) and (18) may be substituted into the equation (19), and then the equation substituted into the equation (1) may be used. Further, when the membrane filtration prediction is composed of the above (d) (that is, calculation step 1a and / or calculation step 1b and / or calculation step 1c and calculation step 2 and calculation step 4), the membrane obtained in calculation step 2 is obtained. The filtration resistance value is used to calculate the membrane filtration flow rate (flux) value at an arbitrary time. As the method, it is preferable to calculate using the above formula (1) or a mathematical formula based on the above formula (1).

In the present invention, when the membrane filtration prediction when the membrane filtration is continued while controlling the membrane filtration flow rate to a set value is performed by repeating the calculation step while updating the time, the membrane filtration resistance over time When the change and / or the change over time of the intermembrane differential pressure is obtained and the membrane filtration is predicted when the membrane filtration is continued while controlling the intermembrane differential pressure to a set value, the membrane filtration resistance over time is used. Find the change and / or the change over time in the membrane filtration flow rate (fluctuation).

In the present invention, the frequency of predicting the change over time is not limited, but the prediction result does not change significantly when the sludge membrane filtration property is stable, and the prediction result also changes when the sludge membrane filtration property changes. Therefore, it is preferable to obtain the change with time at the timing when the membrane filtration property of sludge changes. That is, it is preferable to predict the change with time when the membrane filterability parameter deviates from a predetermined reference range or a predetermined rate of change.
Table 1 summarizes the explanations of the symbols used in each formula.

In the membrane separation activated sludge method, if the operating conditions are inappropriate or unstable (raw water quality fluctuations, water temperature fluctuations, after washing the membrane with a chemical solution, etc.), the condition of the activated sludge tends to deteriorate, in which case the activated sludge When the amount of suspended matter in the aqueous phase is large and the amount of suspended matter in the aqueous phase is large, it easily adheres to and accumulates on the surface or pores of the membrane when the membrane is filtered, and the membrane is easily blocked. That is, the membrane filtration parameter deteriorates.

After imaging the activated sludge collected from the membrane separation activated sludge tank by optical means, the captured image is processed, the membrane filtration parameter is calculated, the membrane filtration parameter and / or the prediction result, the value of the number of operable days and its value. By comparing the rate of change with a preset reference range, the effects of sludge conditions and operating conditions in the membrane separation activated sludge method are evaluated, and warnings and / or operations are performed before the membrane filtration pressure begins to rise. It is possible to output the control for optimizing the conditions.

Here, the number of operable days is defined as the time-dependent change in membrane filtration resistance and / or the time-dependent change in membrane filtration differential pressure and / or the time-dependent change in membrane filtration flow rate (flulux) obtained by prediction of change over time. It is the number of operating days until the set value is reached.
In Table 2, images of 10 fields are taken for the same activated sludge, image information elements and membrane filterability parameters in each image are calculated, averaged, and image information elements and membrane filtration of the activated sludge. Image processing is performed by taking a plurality of images in order to use them as sex parameters. In the same activated sludge, if image processing is performed from the image processing result of one field of view, an error may occur. Therefore, it is preferable to use the average value of the image processing results of a plurality of fields of view as the image processing result. Judgment accuracy is improved by making a judgment using images in as many observation areas as possible. In order to obtain images of many observation areas, it is preferable to replace the activated sludge with the observation jig 44 and the liquid feeding means 75 described later to automatically increase the observation field of view.

In the present embodiment, the wastewater treatment conditions are controlled in order to detect the state of the membrane separation activated sludge and suppress the increase in membrane filtration pressure, deterioration of filtered water quality, etc. by using the evaluation result and / or the prediction result. The object to be controlled is at least one of the following items.
(A) Inflow concentration and inflow amount of water to be treated (B) Filtration flow rate (C) Filtration time or filtration stop time (D) Aeration air volume or aeration time (E) Nutrient salt addition amount (F) Chemical addition amount (G) Activity Amount of sludge (H) Amount of returned treated water (I) Operating conditions of pretreatment process (J) Operating conditions of posttreatment process (K) Activated sludge tank temperature adjustment conditions (L) Operating conditions of membrane element (M) Operating conditions of membrane element (N) Air diffuser cleaning conditions

FIG. 4 is used again to show an example of the embodiment of the present invention. By imaging the active sludge with the optical means 41 and the camera 43 and image-processing with the image processing means 42, (vi) the area of the solid phase region below a certain area surrounded by the aqueous phase region and / or the aqueous phase region. Alternatively, the membrane filterability parameters related to the progress rate of cake resistance and pore clogging are calculated from the area ratio to the solid phase region using a preset calculation formula, and the parameter calculation value and / or the prediction result and the value of the number of operable days are calculated. When the rate of change deviates from the preset reference range, an alarm is output by the alarm output means 49, and the membrane filtration pressure is increased by, for example, (D) controlling the aeration air volume or the aeration time accordingly. And it becomes possible to suppress the deterioration of the filtered water quality.

The alarm output by the alarm output means 49 is a notification indicating that the value of the number of operable days or the rate of change, which is the result of the membrane filtration parameter or the membrane filtration prediction, has deviated from the control range, and is the control panel of the device. There is a function of displaying characters on the screen in, the display method may be changed according to the degree of urgency, sound may be used, or reception may be performed at a remote location using a communication device.

In order to improve the accuracy of the determination result, the alarm output means 49 may output an alarm and control the operating conditions only when both the membrane filtration parameter and the number of operable days deviate from the control range. Furthermore, the alarm output display is provided step by step, and if only one type of membrane filtration parameter deviates from the control range, only the notification display is provided, and if two or more types deviate from the control range at the same time, control is required. It may be set to display that there is.

The state of activated sludge changes depending on the water quality to be treated, the operating conditions of the membrane-separated activated sludge process and the upstream treatment process. In order to accurately grasp the state of the activated sludge, the activated sludge is continuously or periodically collected from the membrane-separated activated sludge tank, imaged by the optical means 41 and the camera 43, and image-processed by the image processing means 42. There is a need. Therefore, the activated sludge visualization device 52 of the present invention is provided with a suction pump 47 for collecting activated sludge from the membrane separation activated sludge tank 3, and the activated sludge is continuously or periodically generated by a signal from the activated sludge visualization control unit 51. It is preferable to collect the sample and visualize the state of activated sludge. The term “regular” as used herein is exemplified by a preset time once a day, once every three hours, and the like.

Below, using FIG. 8, an example of control using an image information element, a membrane filtration parameter, and a membrane filtration prediction result is shown. The system of the example shown in FIG. 8 includes an immersion type membrane separation unit 2, a membrane separation active sludge tank 3, a raw water supply pump 6 for supplying wastewater 1, an air pump (air supply device) 7, an air diffuser pipe 8, and a suction pump. 9. Active sludge extraction pump 10, nutrient addition pump 13 for adding nutrients in nutrient addition tank 12, chemical addition pump 15 for adding chemicals in chemical addition tank 14, cleaning of cleaning chemical addition tank 16. Cleaning chemical addition pump 17 for adding chemicals, nutrient salt addition flow

path switching valves

18a and 18b, cleaning chemical flow

path switching valves

19a and 19b, cleaning chemical discharge valve 20, and spare tank for draining drainage 22 from the spare tank 21. It includes a drainage pump 24, a spare tank liquid feed pump 23 for feeding liquid from the reserve tank 21 to the membrane separation active sludge tank 3, and a wastewater (water to be treated) flow path switching valve 25. Further, as an example, the collection port 53 shown in FIG. 4 is installed in the membrane separation active sludge tank 3 of FIG. 8, and the activated sludge is collected and supplied to the activated sludge visualization device 52.

In the biological treatment of the membrane separation activated sludge tank, in order to stabilize the biological treatment, the balance between the amount of organic matter contained in the inflowing wastewater 1 and the amount of active sludge in the membrane separation activated sludge tank 3 that decomposes it should be kept constant. It is important to prepare. The amount of organic matter referred to here is represented by BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), or TOC (Total Organic Carbon Demand), which are general water quality indicators. The load per unit activated sludge amount, for example, BOD / MLSS load is calculated and managed to be about 0.05 to 0.2 kgBOD / kgMLSS / day, more preferably about 0.07 to 0.15 kgBOD / kgMLSS / day. According to the present embodiment, the membrane filterability parameters related to the cake and pore occlusion rate are monitored, and when the control range is exceeded, the sludge state in the activated sludge deteriorates and the membrane filterability deteriorates. As an alarm, for example, "Please check if the BOD / MLSS load is within the control range" is displayed, and according to the displayed content, (A) the BOD concentration of wastewater 1 which is the water to be treated. It is exemplified that the amount of inflow and the amount of (G) activated sludge are confirmed to be within an appropriate range, and if they deviate from the control range, they are controlled to be within the range.

In addition, although not shown, if a temperature control function is installed to maintain the biological processing activity, "Please check the temperature adjustment conditions" is displayed as an alarm and the set temperature is adjusted. , (K) It is also preferable to control the temperature adjustment conditions of the activated sludge tank. For example, if the temperature inside the activated sludge tank drops or rises and the microorganisms in the activated sludge deviate from the optimum temperature range for biodegrading organic substances in the inflow water, the biodegradation ability of the microorganisms becomes high. Raise the temperature of the activated sludge tank to the optimum temperature range because it decreases and the self-defense function of microorganisms works to generate or kill metabolites, which makes it easier to increase the amount of suspended matter in the aqueous phase. Alternatively, by lowering it, the biodegradation ability of microorganisms is maintained, and stable operation becomes possible without increasing the amount of suspended matter in the aqueous phase. Not only organic substances but also trace components such as nitrogen and phosphorus are required for biological treatment, and when the amount of nutrients added from (E) nutrient addition tank 12 shown in FIG. 8 is additionally adjusted, the water to be treated The water quality of wastewater 1 may change, causing a temporary shortage of trace components such as nitrogen and phosphorus, which worsens the sludge condition and worsens the membrane filterability parameters related to cake and pore blockage. Sometimes. Therefore, the membrane filtration parameters related to cake and pore occlusion are monitored, and if it exceeds the control range, it is determined that the sludge state is deteriorated and the membrane filtration property of activated sludge is deteriorated. FIG. An alarm may be output to additionally adjust the amount of nutrients added from the nutrient addition tank 12 shown in (E).

In addition, the pH of the activated sludge in the membrane separation active sludge tank 3 may fluctuate to be acidic or alkaline in the process of the water quality fluctuation of the wastewater 1 or the biological treatment reaction by the activated sludge in the membrane separation active sludge tank 3. Therefore, when the membrane filtration parameter related to cake or pore blockage exceeds the control range, it is determined that the sludge state in the activated sludge has deteriorated and the membrane filtration property has deteriorated, and "pH is confirmed. Please do it. " Further, when the pH of the active sludge in the membrane-separating active sludge tank 3 is changed to acidic or alkaline by interlocking with the pH meter of the chemical addition tank 14 shown in FIG. 8 by using the alarm output and the control device, The chemical addition tank 14 shown in FIG. 8 may be controlled to add an acid (for example, hydrochloric acid or sulfuric acid) or an alkali (for example, sodium hydroxide) for neutralization as the adjustment of the amount of the chemical addition (F). Here, when the value or rate of change of the membrane filtration parameter related to cake or pore occlusion deviates from the control range, the selection of the alarm content to be output is the most based on the past results investigated separately in advance. It may be in the order of troubles that have occurred, or in the order of various sensors provided in the membrane separation activated sludge tank 3 registered in advance. Further, the alarm output may be recorded separately and changed sequentially so as to be in the order of troubles that are likely to occur in the processing process. As the chemical solution, in addition to the acid and alkali used for adjusting the pH of the activated sludge, it is added to the wastewater 1 in or upstream of the membrane-separated activated sludge tank 3 to coagulate aqueous phase suspended matter and soluble substances in advance. Examples thereof include a flocculant and an antifoaming agent for suppressing the foaming of activated sludge.

In addition to this, according to the present invention, activated sludge is imaged and image-processed by optical means before and after the change of operating conditions, so that the effect can be immediately obtained without performing analysis using a conventional water quality analyzer. Since it is possible to determine, there is an effect that the time required for changing the condition is significantly shortened.

In addition, even when the filtration pressure rises regularly only in a specific membrane element, the activated sludge around it is collected, the membrane filtration parameter related to pore occlusion is monitored, and the parameter related to pore occlusion rate. If the values and rate of change of parameters related to the pressure dependence of pore occlusion and the predicted operating days are out of the control range, the air diffuser below the membrane element may be clogged. Therefore, it is also preferable to adjust the flow rate of the air pump 7 (N) to clean the air diffuser pipe 8 or to replace, for example, a rubber resin member constituting the air diffuser pipe.

According to the present embodiment, by continuously or periodically imaging activated sludge, in addition to the membrane filtration parameters, the area and / or water of the solid phase region of image information (viii) constant color tone or constant brightness or less. Monitor the area ratio to the phase region or solid phase region, and if the membrane filtration parameter deteriorates and the color tone of the solid phase region changes from brown to black, "dissolved oxygen in the activated sludge tank". The concentration may have decreased. ”Is displayed an alarm, and based on the display, measure the dissolved oxygen concentration in the activated sludge tank and check if the air volume of the air pump is out of the control range. However, if there is no problem with the air volume, there is a possibility that the air supply is biased in a part of the tank due to the clogging of the air diffuser pipe. Therefore, (N) the air diffuser pipe cleaning should be performed. When there are a plurality of series of air diffuser pipes 8, in order to determine the order of cleaning, activated sludge at a plurality of locations in the membrane separation activated sludge tank 3 is collected, and a judgment is made for each of the locations that deviate from the control range. If there is, it is possible that the air diffuser in the vicinity is clogged. Therefore, preferentially adjust the flow rate of the air pump 7 to clean the air diffuser 8 in the vicinity or clean the air diffuser. For example, it is also preferable to replace the constituent rubber resin member.

On the other hand, the (C) filtration time or filtration stop time of the suction pump 9 can be adjusted, or the (D) aeration air volume or aeration of the air pump 7 can be adjusted according to the state of the activated sludge in the membrane separation activated sludge tank 3 and the predicted result. The time may be increased or decreased or adjusted intermittently. For example, energy saving is achieved by (D) reducing the aeration air volume or the aeration time while confirming that there is no problem in the membrane filtration parameters and the membrane filtration prediction result even if the aeration air volume or the aeration time is reduced. be able to. In particular, monitor the rate of change of membrane filtration parameters related to cake and pore blockage, and if the rate of change is less than or equal to the preset control value, (D) reduce the aeration air volume or aeration time and operate, and the rate of change is greater than or equal to the control value. In the case of (D), it is preferable to increase the aeration air volume or the aeration time for operation. Similarly, the number of operable days calculated by membrane filtration prediction is monitored, and the number of operational days is managed by reducing the aeration air volume or aeration time within the range where the operational days do not deviate from the preset control range. When it deviates from the range, (D) it is preferable to increase the aeration air volume or the aeration time for operation. Further, it is also preferable to adjust by combining (C) the filtration time or the filtration stop time and (D) the aeration air volume or the aeration time, respectively.

In addition to these, (A) in the case of a wastewater treatment facility where the inflow concentration and inflow amount of water to be treated are likely to fluctuate, the state of the active sludge in the membrane separation active sludge tank 3 based on the membrane filtration parameters and the membrane filtration prediction results. While monitoring that there is no adverse effect on the water, (A) adjust the (C) filtration time or filtration stop time of the suction pump 9 according to the inflow concentration and inflow amount of water to be treated, or (D) of the air pump 7. The aeration air volume or aeration time may be increased or decreased, or may be adjusted intermittently. Further, (C) and (D) may be combined and adjusted respectively.

Further, according to the present embodiment, if there is no change in the intermembrane differential pressure even though the membrane filterability parameter is rapidly deteriorated, the membrane is checked for breakage, for example. It is also suitable for the maintenance of separation membranes for separation activated sludge treatment.

FIG. 9 schematically shows the configuration of the observation jig 44 used for continuous observation of activated sludge in one embodiment of the present invention. The observation jig 44 is evaluated at intervals of 0.01 to 0.1 mm in which a pair of upper and lower transparent members 72 mounted on the gantry 71, for example, a pair of transparent members 72 such as transparent glass and acrylic resin are arranged facing each other. It is composed of a flow path 74 and an activated sludge transport flow path 73 that communicates with the evaluation flow path 74 from a liquid feeding line 46 that is directly connected to the evaluation flow path to the water treatment tank. The activated sludge 70 is imaged by the optical means 41 and the camera 43 through the liquid feeding means 75 for feeding the activated sludge 70 into the evaluation flow path 74 and the evaluation flow path 74. The optical means 41 includes a lens 41a, a phase difference / bright field switching / optical filter means 41b, and a light source 41c for switching between a phase difference image and a bright field image of the activated sludge 70 for observation. The material of the member for maintaining the gap between the activated sludge transport flow path 73 of the observation jig 44 and the evaluation flow path 74 is not particularly limited, but a metal such as acrylic resin or stainless steel, which is easy to process, is preferable, and chemical resistance is preferable. Stainless steel (SUS) 316 is preferable because of its properties and abrasion resistance.

Here, the operation of the observation jig 44 used for continuous observation of activated sludge will be described.
The activated sludge 70 is sent from the membrane separation activated sludge tank 3 to the evaluation flow path 74 formed by the transparent member 72 mounted on the gantry 71 via the activated sludge transport flow path 73 by the liquid feeding means 75. The liquid feeding means 75 includes a liquid feeding control means (not shown) for controlling the liquid feeding amount. The liquid feeding means 75 may feed the activated sludge 70 collected in advance to a container (not shown), or may collect the activated sludge 70 through a movable collection port 53 installed in the membrane separation activated sludge tank 3. The liquid feed control means is not particularly limited as long as the activated sludge 70 can be smoothly fed, but it is preferable that the speed can be selected such as acceleration, deceleration, or liquid feed at a constant speed, and the liquid feed is stopped for a certain period of time at the time of imaging. Is preferable. Instead of stopping the liquid feeding for a certain period of time at the time of imaging, both ends (inlet and outlet of activated sludge) of the evaluation flow path 74 may be physically blocked. For example, solenoid valves may be provided at both ends of the transparent flow path in order to physically block the flow path. The liquid feeding means 75 is preferably, but is not limited to, a pump that can feed or stop the liquid or control the liquid feeding speed by an electric signal from the outside. At the time of imaging, the activated sludge feed is temporarily stopped and left for a certain period of time, or the activated sludge 70 is temporarily closed by using a physical closing means such as a solenoid valve that blocks the inlet side and the outlet side of the evaluation flow path 74. Stop the flow and take an image. By taking an image in a state where the flow of the activated sludge 70 is stopped in this way, the solid phase region and the aqueous phase region can be accurately distinguished, and the amount of suspended solids in the aqueous phase can be detected.

The distance between the gaps between the pair of transparent members 72 constituting the evaluation flow path 74 is not particularly limited, but 0.01 to 0.1 mm is preferable in consideration of the size of the flocs. Further, it is also preferable that the distance between the transparent members 72 constituting the evaluation flow path 74 is inclined so that the flow path becomes narrower toward the portion provided with the gap of 0.01 to 0.10 mm. In order to reduce clogging during activated sludge feeding, it is also preferable to add an adjustment function for adjusting the gap interval, and to change the gap of the transparent member 72 between activated sludge feeding and observation. is there. By varying the gap in the evaluation flow path 74, it is possible to keep the gap between the gaps suitable only during observation, and to widen the gap in other cases to prevent clogging of activated sludge in the flow path. Furthermore, as described above, during observation, the thickness of the flow path is positively changed and the shape of the activated sludge is changed in the thickness direction to investigate the degree of change in the solid phase region in the image before and after the change, and according to the degree of change. It is suitable because it enables quantitative evaluation of the density, degree of aggregation, constituents, etc. of activated sludge. The adjustment function for varying the gap of the evaluation flow path 74 is not particularly limited, and the thickness of the gap in the vertical direction may be changed by an electric signal or manually. Further, by keeping the thickness of the flow path constant and changing the intensity and type of transmitted light, the density, the degree of aggregation, the constituent components, etc. in the thickness direction of the activated sludge may be quantified together with the position information. In particular, it is also preferable to mark microorganisms in advance with a fluorescent dye or the like and use a fluorescence microscope to quantify the density, agglutination degree, etc. of the marked microorganisms together with position information. In the activated sludge collected from the membrane-separated activated sludge tank 3, depending on the stirring condition of the activated sludge, the activated sludge may stay at the bottom of the tank, or there are many components such as oil that easily float near the water surface of the tank. Since there may be a difference in the state of activated sludge, it is preferable to collect activated sludge in an average state in the tank. Therefore, the collection port 53 is movable in the depth direction so that the activated sludge can be collected from any place in the depth direction of the membrane separation activated sludge tank, whereby the average in the depth direction of the membrane separation activated sludge tank It is possible to collect activated sludge. For example, when samples are taken from three different depths and the difference in the total area of the solid phase region in the activated sludge at each depth becomes large, the air diffuser for stirring is partially clogged and the activated sludge is stirred. (N) The air diffuser pipe 8 may be washed, or the rubber resin member constituting the air diffuser pipe may be replaced.

Although the collection method is not shown, for example, three collection ports to which three types of collection tubes having different lengths are attached may be immersed in the activated sludge tank, or three locations in the depth direction in advance. It is also possible to immerse a sampling pipe with a sampling port provided with an on-off valve in an activated sludge tank, open the on-off valve at one of the three locations at a preset time, and suck the sludge with the rest closed. Good.

In addition, the collection port 53 is provided with an expansion / contraction function and a direction adjustment function, and the activated sludge is first moved horizontally to the target location at the upper part of the activated sludge tank and then moved in the depth direction to collect activated sludge. It may be collected.

The activated sludge liquid supply line 46 from the collection port 53 to the suction pump 47 and the activated sludge visualization device 52 includes general tubes, hoses, hard polyvinyl chloride (HIVP) used for water pipes, and stainless steel pipes. Is used. The material of the tube and hose is not particularly limited, and general silicon, nylon, polypropylene, polyurethane and the like are suitable.

A light source 41c, a lens 41a for observing and imaging, and a camera 43 are provided with the evaluation flow path 74 sandwiched so that light passes through the surface of the evaluation flow path 74 in the vertical direction sandwiched between the transparent members 72. The phase difference, bright field switching, and the position of the optical filter means 41b are adjusted so as to be in an appropriate position. As shown by the arrows in the figure, the light from the light source 41c passes through the phase difference / bright field switching / optical filter means 41b, the transparent member 72 constituting the evaluation flow path 74, and the activated sludge 70. This light is imaged by the camera 43 to which the lens 41a is attached. The captured image acquired by the camera 43 is sent to the image processing means 42. The lens 41a is not particularly limited as long as the required magnification and field of view can be secured, but it is preferable to use an objective lens having a magnification suitable for the sizes of flocs and aqueous phase suspended matter, and in the present invention, the magnification is 2 times or more and 1000 times. The following is preferable, and 10 times or more and 100 times or less is more preferable. The phase difference / bright field switching / optical filter means 41b is composed of a ring slit, a retardation plate, a dedicated objective lens, and the like so that the phase difference image and the bright field image can be switched and observed. When capturing a retardation image, observe through a ring slit, a retardation plate, a dedicated objective lens, etc., and when capturing a bright field image, do not pass through a ring slit, a retardation plate, a dedicated objective lens, etc. Observe. The phase difference / bright field switching / optical filter means 41b may be controlled by an electric signal, or may be manually switched by the observer at an arbitrary timing. Further, although not shown, a surface through which light can pass in the evaluation flow path may be provided in a plurality of directions in the vertical and horizontal directions, and the light to be passed may be applied from a plurality of directions, or the camera 43 may capture images from a plurality of directions. In order to facilitate imaging of the evaluation flow path from another direction, the observation jig itself or the evaluation flow path may have a rotatable structure.

The activated sludge contains a large amount of gas components such as gas generated by the air diffuser 8 and bubbles generated by biological treatment. The activated sludge is imaged by the optical means 41 and the camera 43 in the state of containing the gas. When image processing is performed by the processing means 42, accurate processing may not be possible. Therefore, by installing the degassing device 45 in the liquid feeding line 46 that feeds the activated sludge to the optical means 41 and removing the gas component of the activated sludge, accurate treatment becomes possible.

The degassing device 45 may be any device such as a ball valve or a needle valve as long as it is a mechanism capable of discharging gas in general, but it is attached to the upper part of the liquid feeding line 46 in order to enable efficient exhaust. Is preferable.

In the present embodiment, the activated sludge collected from the membrane separation activated sludge tank is imaged by an imaging means including an optical means 41 and a camera 43, image processing is performed by the image processing means 42, and the membrane filtration calculated as the image processing result is performed. It has a determination means 48 for determining that an abnormality occurs when the membrane filtration prediction result performed using the sex parameter or the membrane filtration property parameter deviates from a preset control reference range.

Judgment as to whether or not there is a deviation from the control standard range may be made by incorporating judgment conditions in the control software of the camera based on a judgment formula created in advance based on past achievements and knowledge based on preliminary studies, or by incorporating the above judgment formula. The image processing result may be imported into a personal computer or the like for determination. All of these are connected to the alarm output means 49 that outputs an abnormality alarm, and outputs an alarm when the determination result deviates from the preset control reference range. A monitor may be provided to display the captured image, image processing conditions, judgment result and alarm content on the monitor according to the judgment result, and the wastewater treatments (A) to (N) corresponding to the judgment result may be displayed. It is more preferable to display the condition control method as well.

The evaluation frequency in the present embodiment is not particularly limited, and when the membrane separation activated sludge tank is operated stably, for example, it is evaluated once a day for about 1 hour, depending on the determination result. After the wastewater treatment conditions of (A) to (N) are controlled by the control means 50, it is preferable to carry out the control continuously until it can be confirmed that the state of the activated sludge is stable.

Here, as an evaluation, sludge is collected from the membrane separation activated sludge tank, imaged, sludge is discharged, image processing is performed, and the process of calculating the membrane filtration parameter is set as one set, and about 30 sets are performed. Is exemplified. The evaluation is carried out while operating the membrane separation activated sludge tank.

By observing the degree of change in the state of activated sludge on a regular basis, it is possible to detect the change in the state of activated sludge in the membrane-separated activated sludge tank at an early stage and determine the presence or absence of abnormalities. It is possible to control various wastewater treatment conditions to improve the condition of activated sludge before the rise occurs.

In the present embodiment, it may be a wastewater treatment system management program for making various control means for controlling the wastewater treatment conditions (A) to (N) by the control means 50 according to the determination result, or a computer. It may be incorporated into a wastewater treatment system as a recording medium that can be read by. As a result, the activated sludge collected from the membrane separation activated sludge tank is imaged and image-processed by optical means to determine the membrane filterability and the number of operating days, and when the determination result deviates from the predetermined management standard. It is preferable that an alarm is displayed and the various wastewater treatment conditions (A) to (N) are automatically controlled.

The activated sludge image captured by the activated sludge visualization device 52 of the present embodiment and the image processing result are monitored and determined even at a remote location by connecting to a remote monitoring server via the communication device 54. , It is possible to control various wastewater treatment conditions (A) to (N). PLC (Programmable Logic Controller), which is a control device that performs sequential control according to a program, which is usually installed in a wastewater treatment system, and DCS, a distributed control system that communicates with each other and monitors each other, have control devices in each device that composes the system. It may be installed together with a control management system such as (distributed control system), and operation data may be retrieved from the control management system via a remote monitoring device and installed on a cloud server installed at an arbitrary location. ..

As a result, it is not necessary for workers to go to the site to check the state of activated sludge, and the operating conditions of the membrane separation activated sludge process and its upstream treatment process can be controlled from a remote location, increasing the filtration pressure and deteriorating the quality of filtered water. It is possible to implement improvement measures before a fatal trouble such as the above occurs. The remote location referred to here may be a central control room or the like in another building in the plant, or may be either a centralized control center in a region or a country.

The present invention is intended to minimize an increase in the filtration pressure of the membrane due to deterioration of the state of activated sludge and to realize long-term stable operation, and is not particularly limited.

This application is based on a Japanese patent application filed on April 19, 2019 (Japanese Patent Application No. 2019-079914), the contents of which are incorporated herein by reference.

1: Wastewater (water to be treated)
2: Immersion type membrane separation unit 2a: Flat membrane element 2b: Flat membrane separation functional layer 2c: Flat membrane base material 2d: Frame 3: Membrane separation active sludge tank 4: Filtered water tank 5: Filtered water 6: Raw water supply pump 7: Air pump (air supply device)
8: Air diffuser 8a: Bubbles
9: Suction pump 10: Activated sludge extraction pump 11: Extraction activated sludge (surplus activated sludge)
12: Nutrient addition tank 13: Nutrient addition pump 14: Chemical addition tank 15: Chemical addition pump 16: Cleaning chemical addition tank 17: Cleaning chemical addition pump 18a: Nutrient addition flow path switching valve 18b: Nutrient addition flow path Switching valve 19a: Cleaning chemical flow path switching valve 19b: Cleaning chemical flow path switching valve 20: Cleaning chemical discharge valve 21: Spare tank 22: Spare tank drainage 23: Spare tank liquid feed pump 24: Spare tank drainage pump 25: Waste water ( Water to be treated) Flow path switching valve 41: Optical means 41a: Lens 41b: Phase difference / bright field switching / optical filter means 41c: Light source 42: Image processing means 43: Camera 44: Observation jig 45: Degassing device 46: Liquid feeding line 47: Suction pump 48: Judgment means (judgment unit)
49: Alarm output means (alarm output unit)
50: Control means 51: Activated sludge visualization control unit 52: Activated sludge visualization device 53: Collection port 54: Communication device 61: Solid phase region 62: Aqueous phase region (non-solid phase region)
63: Aqueous suspended matter (solid phase with a certain area or less)
70: Activated sludge 71: Stand 72: Transparent member 73: Activated sludge transport flow path 74: Evaluation flow path 75: Liquid feeding means

Claims

In the membrane separation activated sludge method, which separates raw water into treated water and activated sludge using a separation membrane,
A sludge imaging process in which activated sludge is imaged by optical means to obtain a sludge image,
A sludge image processing step of processing the sludge image to obtain sludge image information,
A parameter calculation method comprising a parameter calculation step of calculating a membrane filterability parameter based on the sludge image information.
The membrane filtration parameter is any one of the cake adhesion rate, the cake peeling rate, the cake resistance, the non-peeling cake formation rate, the non-peeling cake resistance, the progress rate of the closure of the separation membrane pores, and the resistance due to the closure of the separation membrane pores. The parameter calculation method according to claim 1, wherein the parameters are related to the calculation.
The parameter calculation method according to claim 1 or 2, wherein the sludge image information is image information in which a solid phase region and an aqueous phase region are distinguished.
The parameter calculation method according to claim 3, wherein the membrane filterability parameter is calculated under any of the following conditions (a) to (f).
(A) The membrane filterability parameter is calculated from the image information element obtained for the solid phase region (b) Calculated as a combination of a plurality of membrane filterability parameters calculated in the above (a) (c) The aqueous phase The membrane filterability parameter is calculated from the image information element obtained for the region (d) Calculated as a combination of the plurality of the membrane filterability parameters calculated in the above (c) (e) About the solid phase region and the aqueous phase region. The membrane filterability parameter is calculated from a plurality of required image information elements (f) Calculated as a combination of the plurality of membrane filterability parameters calculated in the above (a) to (e).
The image information element includes the area of the solid phase region, the peripheral length of the solid phase region, the area of the aqueous phase region, the peripheral length of the aqueous phase region, the distance between the solid phase regions, and the space between the solid phase regions. A claim characterized by being at least one of a total value, a maximum value, a minimum value, an average value, a median value, and a deviation value for an element selected from the group consisting of the number and the brightness between the solid phase regions. Item 4. The parameter calculation method according to Item 4.
Of the membrane filtration parameters, parameters related to cake resistance and closure of separation membrane pores are calculated using the total area of the floc region below a certain area surrounded by the aqueous phase region per unit field of view in the image information element. The parameter calculation method according to claim 5, wherein the parameter calculation method is performed.
The parameter calculation method according to any one of claims 1 to 6, wherein the sludge image is an image captured at an imaging magnification of 2 times or more and 1000 times or less.
In the membrane separation activated sludge method, which separates raw water into treated water and activated sludge using a separation membrane,
A sludge imaging process in which activated sludge is imaged by optical means to obtain a sludge image,
A sludge image processing step of processing the sludge image to obtain sludge image information,
A parameter calculation step for calculating the membrane filtration parameter based on the sludge image information, and
A method for predicting separation membrane characteristics, which comprises a time-dependent change prediction step for predicting a time-dependent change in membrane filtration resistance or a time-dependent change in intermembrane differential pressure based on the membrane filtration property parameter.
The method for predicting separation membrane characteristics according to claim 8, wherein the change with time is predicted when the membrane filterability parameter deviates from a predetermined reference range or a predetermined rate of change.
In the membrane separation activated sludge method, which separates raw water into treated water and activated sludge using a separation membrane,
A sludge imaging process in which activated sludge is imaged by optical means to obtain a sludge image,
A sludge image processing step of processing the sludge image to obtain sludge image information,
A parameter calculation step for calculating the membrane filtration parameter based on the sludge image information, and
A time-dependent change prediction step for predicting a time-dependent change in membrane filtration resistance or a time-dependent difference pressure based on the membrane filtration parameter is provided, and operating conditions are controlled from the membrane filtration parameter or the prediction result of the time-dependent change. A method of operating a separation membrane, which is characterized in that.
Controlling operating conditions when the prediction result of the membrane filtration parameter or the change over time of the membrane filtration resistance or the change over time of the intermembrane differential pressure deviates from a predetermined reference range or a predetermined rate of change. 10. The method of operating a separation membrane according to claim 10.
When the predicted date when the membrane filtration resistance or the intermembrane differential pressure deviates from a predetermined reference range is calculated from the prediction result of the change with time, and the number of days until the predicted date deviates from the predetermined reference range. The method for operating a separation membrane according to claim 11, wherein the operating conditions are controlled.
The method for operating a separation membrane according to claim 12, wherein the air volume of air supplied to the separation membrane is controlled when the number of days until the predicted date deviates from a predetermined reference range.
A water treatment device that separates raw water into treated water and activated sludge using a separation membrane.
Sludge imaging means for obtaining sludge images by imaging activated sludge with optical means,
A sludge image processing means for processing the image to obtain sludge image information,
A parameter calculation means for calculating a membrane filtration parameter based on the image information,
A water treatment apparatus comprising a time-dependent change predicting means for predicting a time-dependent change in membrane filtration resistance or a time-dependent change in intermembrane differential pressure based on the membrane filtration property parameter.
Using a separation membrane, a computer is used to predict the separation membrane characteristics in the membrane separation activated sludge method that separates raw water into treated water and activated sludge.
Steps to obtain a sludge image by imaging activated sludge by optical means,
The step of processing the image to obtain sludge image information,
Steps to calculate membrane filtration parameters based on the image information,
A separation membrane property prediction program for executing a step of predicting a time-dependent change in membrane filtration resistance or a time-dependent change in intermembrane differential pressure based on the membrane filtration parameter.
Using a separation membrane, a computer is used to predict the separation membrane characteristics in the membrane separation activated sludge method that separates raw water into treated water and activated sludge.
Steps to obtain a sludge image by imaging activated sludge by optical means,
The step of processing the image to obtain sludge image information,
Steps to calculate membrane filterability parameters based on the image information,
A step of predicting a change over time in membrane filtration resistance or a change over time in intermembrane differential pressure based on the membrane filtration parameter.
An operation program of separation membrane characteristics for executing a step of controlling operating conditions from the membrane filtration parameter or the prediction result of the change with time.
A computer-readable recording medium that records the separation membrane characteristic prediction program according to claim 15 or the separation membrane operation program according to claim 16.