JP2011140017A - Sewage cleaning apparatus and sewage cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sewage cleaning apparatus and sewage cleaning method, capable of achieving long-term stable operation without causing occlusion of a membrane in adopting a biological treatment method different from an activated sludge process. <P>SOLUTION: The sewage cleaning apparatus includes a biological treatment apparatus 10 for obtaining biological treatment water from sewage by bringing sewage into contact with a base material 11 carrying microorganism decomposing dirt contained in sewage water to decompose the dirt; a membrane filtration apparatus 20 for physically separating the biological treatment water into condensed water containing dirt contained in the biological treatment water and filtrate water by making the biological treatment water permeate through the membrane; a solid-liquid separators 30, 40 for separating treatment water containing at least the condensed water into solid and liquid; and circulation apparatuses 6, 7 for circulating the separated water obtained through solid-liquid separation by the solid-liquid separators 30, 40 to the biological treatment apparatus 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sewage purification apparatus and a sewage purification method, and in particular, a biofilm system that decomposes filth contained in sewage by bringing the sewage into contact with a substrate on which microorganisms that decompose filth contained in sewage are supported. The present invention relates to a sewage purification apparatus provided with a biological treatment apparatus, and a sewage purification method using the biological treatment apparatus.

  2. Description of the Related Art Conventionally, a membrane separation activated sludge method (MBR) is known in which wastewater such as domestic wastewater and factory wastewater is biologically treated with microorganisms, and the treated wastewater is permeated through a filtration membrane for purification.

  The activated sludge method is a biological treatment method that biochemically decomposes sewage by bringing the sewage in sewage into contact with a suspension in which microorganisms and their metabolites, secretions, carcasses, etc. are integrated. Since the suspended matter is seen as sludge, it was named as a method using sludge in which microorganisms are active.

  In the sewage purification device equipped with a membrane filtration device, the activated sludge method is mainly used as a biological treatment method, but this is because the suspended matter (sludge) is integrated, including minute matter and viscous substances in the sewage. The particle size is sufficiently large compared to the pore size of the membrane, so that the possibility of clogging the pores of the membrane is low, and in general, microscopic and viscous substances resulting from biological treatment are suspended in the suspension. This is because the viscosity of the sewage tends to be reduced due to the incorporation of the suspension, and it is judged to be preferable in constructing the apparatus due to the characteristics that the suspension does not easily adhere to the membrane surface.

  On the other hand, Patent Document 1 discloses a water purifier that employs a biological treatment method capable of reducing the space and shortening the treatment time for the problem of the activated sludge method that requires a large installation space and a long treatment time. Is disclosed.

  More specifically, a biological treatment device that employs a biofilm method in which sewage is brought into contact with a contact material to which microorganisms are attached, and a biological treatment sewage permeate through a filtration membrane for solid-liquid separation, and processing after solid separation It is a water purifier in which a membrane filtration device for taking water out of the system is disposed in a single treatment tank.

  Patent Document 2 discloses a water treatment apparatus that adds activated carbon to remove contaminants in raw water, and filters activated carbon injection means for adding activated carbon to raw water and treated water to which activated carbon is added. A filtration means for capturing the activated carbon and obtaining filtered water, a collection means for collecting the activated carbon captured by the filtration means, and a circulation means for adding at least a part of the collected activated carbon to the raw water. A water treatment apparatus is disclosed.

JP 7-323295 A JP 2006-102620 A

  However, in the membrane separation activated sludge method, in order to obtain a suspension having the above-described characteristics, it is necessary to maintain the concentration of the suspension at a predetermined high value. The product itself obstructs the permeation of water, and it must be operated with a low amount of permeated water per unit membrane area, and if the membrane area is increased in order to increase the processing capacity, it will cause a significant increase in cost. There was a problem.

  Further, when the biofilm method disclosed in Patent Document 1 is adopted, the installation space can be reduced, but since a suspended matter such as activated sludge is not generated, wastewater generated as a result of biological treatment is generated. It has been found that there is a specific problem that the concentration of the minute matter and the viscous substance gradually increases, and the pores of the membrane are blocked by the minute matter and the viscous substance, resulting in a decrease in processing capability.

  In addition, in the water purifier described in Patent Document 1, a concentrating device for separating and concentrating solids such as precipitates is provided at the bottom of the treatment tank. Even when such a concentrating device is provided, a minute amount in the sewage is provided. It is difficult to separate substances and viscous substances, and it is difficult to stably maintain a high permeate flow rate for a long time with a membrane filtration device.

  In other words, the treated water purified by the biological treatment apparatus adopting the biofilm method is sent to the membrane filtration device and permeated through the filtration membrane to physically separate the filth contained in the treated water, thereby further improving the quality. However, when the water to be treated is retained in the membrane filtration device, the concentration of fine substances and viscous substances contained in the water to be treated in the membrane filtration device is low. As a result, the pores of the membrane are blocked, resulting in a decrease in processing capacity.

  Furthermore, Patent Document 2 only discloses a configuration in which a solid substance called activated carbon in water is captured by a rotating disk type filtration device in which a part of the rotating disk is immersed in water, and the concentration of activated carbon in water is kept constant. In addition, since the rotating disk cannot be a contact material that supports microorganisms, it cannot have a biological treatment mechanism, and problems that occur in the membrane filtration device due to minute substances and viscous substances contained in the liquid to be treated are also disclosed. It is not something.

  An object of the present invention is to provide a sewage treatment apparatus and a sewage treatment method that can be stably operated over a long period of time without causing a clogging of a filtration membrane when adopting a biological treatment method different from the activated sludge method in view of the problems described above. The purpose is to provide.

  In order to achieve the above-mentioned object, the first characteristic configuration of the sewage treatment apparatus according to the present invention is to bring the sewage into contact with a substrate carrying microorganisms that decompose sewage contained in the sewage, thereby decomposing the sewage. A biological treatment apparatus that obtains biologically treated water from the wastewater, and a membrane that permeates the biologically treated water through a filtration membrane and physically separates it into concentrated treated water containing filth contained in the biologically treated water and filtered water. It is in the point provided with the filtration apparatus and the solid-liquid separation apparatus which carries out solid-liquid separation of the treated water containing the said concentrated treated water at least.

  According to the above-described configuration, the biologically treated water treated by the biological treatment device is filtered by the membrane filtration device, and high-quality filtered water is obtained. And since the biologically treated water containing the filth concentrated by the membrane filtration device, that is, the concentrated treated water is taken out without staying in the membrane filtration device, the minute matter contained in the biological treatment water in the membrane filtration device The increase in the concentration of the viscous substance is suppressed, and as a result, the clogging of the pores due to the viscous substance contacting the membrane surface is avoided, and the sewage treatment apparatus can be stably operated for a long time. Further, the concentrated treated water concentrated in the membrane filtration apparatus and taken out to the outside is subjected to solid-liquid separation by a solid-liquid separation apparatus, and the separated solid component is discarded as a dehydrated cake. Note that the liquid component separated by the solid-liquid separation device can be further purified as necessary, or can be reused for purposes commensurate with its quality, although the quality is lower than that of filtered water.

  In the second feature configuration, in addition to the first feature configuration described above, the solid-liquid separator is supplied with the concentrated treated water discharged from the membrane filtration device, and the solid dispersion in the concentrated treated water And a dehydrator for separating the agglomerates into solids and separated water.

  According to the above configuration, the concentrated treated water in which the filth is concentrated in the filtration process by the membrane filtration device is sent to the solid-liquid separation device. In the solid-liquid separation device, the coagulating device and the solid dispersion in the concentrated treated water are used together with the viscous substance. Are agglomerated, and the agglomerates are separated into solids and separated water by a dehydrator. The separated water can be further purified as necessary, or can be reused for a purpose corresponding to that although the quality is lower than that of filtered water.

  The third characteristic configuration is a biological treatment device that obtains biologically treated water from the sewage by bringing the sewage into contact with a substrate carrying microorganisms that decompose the filth contained in the sewage, and decomposing the filth. A solid-liquid separation device for solid-liquid separation of the solid dispersion in the biologically treated water, and a filth contained in the biologically treated water by allowing the treated water solid-liquid separated by the solid-liquid separator to permeate through a filtration membrane. It is in the point provided with the membrane filtration apparatus which physically isolate | separates into a concentrated process water and filtered water.

  According to the above-described configuration, since the treated water from which the minute matter and the viscous substance contained in the biologically treated water are separated by the solid-liquid separator is supplied to the membrane filtered device, it is included in the biologically treated water in the membrane filtered device. The increase in the concentration of fine substances and viscous substances is effectively suppressed, and as a result, clogging of pores due to viscous substances that come in contact with the membrane surface is avoided, and the sewage treatment apparatus can be operated stably over a long period of time. Become.

  In the fourth characteristic configuration, in addition to the first or third characteristic configuration described above, the solid-liquid separation device is discharged from the concentrated treated water discharged from the membrane filtration device and the biological treatment device. The biological treated water is supplied, the solid dispersion in the mixed water of the concentrated treated water and the biological treated water is subjected to solid-liquid separation, and the treated water solid-liquid separated by the solid-liquid separator is supplied to the membrane filtration device. Is in the point to be.

  According to the above-described configuration, the concentrated treated water in which the filth is concentrated in the filtration process by the membrane filtration device and the biological treated water discharged from the biological treatment device are sent to the solid-liquid separation device. A viscous substance is separated into a separated liquid as a solid together with the solid dispersion. Since the separation liquid is supplied to the membrane filtration device, the concentration of fine substances and viscous substances that may cause clogging of the filtration membrane can be kept low, and high filtration performance in the membrane filtration device can be maintained over a long period of time. it can. The separation liquid can be further purified as necessary, or can be reused for a purpose corresponding to that although the quality is lower than that of filtered water.

  In addition to any of the first to fourth characteristic configurations described above, the fifth characteristic configuration includes a circulation device that circulates the separated water that has been solid-liquid separated by the solid-liquid separation device to the biological treatment device. There is in point.

  According to the above-described configuration, after the fine substances and viscous substances contained in the biologically treated water are separated and removed together with the solids having a relatively large particle size by the solid-liquid separation apparatus, they are circulated to the biological treatment apparatus via the circulation device. Therefore, it is possible to reduce the concentration of fine substances and viscous substances contained in the biologically treated water output from the biological treatment apparatus while realizing advanced biological treatment with the biological treatment apparatus.

  In addition to the fifth characteristic configuration described above, the sixth characteristic configuration includes a circulation device that circulates the concentrated treated water discharged from the membrane filtration device to the biological treatment device.

  According to the above-described configuration, the concentrated treated water that is concentrated and discharged in the membrane filtration device is effectively circulated to the biological treatment device via the circulation device while effectively avoiding clogging of the filtration membrane. Avoiding clogging of fine pores and viscous substances that contact the surface, allowing the sewage treatment device to operate stably over a long period of time, while treating the entire amount of treated water as high-quality treated water through the membrane filtration device. Can be purified.

  In addition to any one of the first to sixth feature configurations described above, the seventh feature configuration includes a membrane clogging index in the membrane filtration device using the biologically treated water or the treated liquid separated into solid and liquid. The measurement device includes a measurement device and a device that prevents film clogging based on the film clogging index measured by the measurement device.

  Since the occurrence of film clogging is avoided by the apparatus for preventing film clogging based on the film clogging index measured by the measuring apparatus, the sewage treatment apparatus can be stably operated over a long period of time.

  In the eighth feature configuration, in addition to the fifth or sixth feature configuration described above, measurement is performed to measure a membrane clogging index in the membrane filtration device by the biologically treated water or the solid-liquid separated treated water. And a control device for adjusting the amount of water circulated by the circulation device based on the film clogging index measured by the measurement device.

  Based on the film clogging index measured by the measurement device, the amount of water circulated to the biological treatment device by the circulation device is adjusted by the control device, so even if the nature of the sewage sent to the biological treatment device varies In addition, the concentration of the minute matter and the viscous substance of the water to be treated sent from the biological treatment apparatus to the membrane filtration apparatus can be adjusted. As a result, clogging of the pores due to a viscous substance that contacts the membrane surface is appropriately avoided, and the sewage treatment apparatus can be stably operated over a long period of time.

  The first characteristic configuration of the sewage purification method according to the present invention is that biological wastewater is treated from the sewage by bringing the sewage into contact with a substrate on which microorganisms that decompose sewage are supported to decompose the sewage. A biological treatment step to be obtained; a membrane filtration step of permeating the biological treatment water through a filtration membrane to physically separate the concentrated treatment water containing filth contained in the biological treatment water and the filtered water; and at least the concentration treatment And a solid-liquid separation step for solid-liquid separation of treated water containing water.

  The second characteristic configuration is a biological treatment step of obtaining biologically treated water from the sewage by bringing the sewage into contact with a substrate carrying microorganisms that decompose the filth contained in the sewage and decomposing the filth. A solid-liquid separation step for solid-liquid separation of at least the biologically treated water-treated water, and a concentrated treated water containing the filth contained in the separation liquid by allowing the separation liquid in the solid-liquid separation step to pass through a filtration membrane; And a membrane filtration step of physically separating the filtrate into filtered water.

  As described above, according to the present invention, when a biological treatment method different from the activated sludge method is adopted, a sewage treatment apparatus and a sewage treatment method capable of stable operation over a long period of time without causing clogging of the filtration membrane are provided. I was able to do that.

The block block diagram of the sewage treatment apparatus by 1st Embodiment of this invention. A perspective view of a rotating disk type water purifier as an example of a biological treatment device Block diagram of a sewage treatment apparatus including a control device that can adjust the circulation amount of water to be treated according to the second embodiment of the present invention The block block diagram of the sewage treatment apparatus which shows 3rd Embodiment of this invention and is not equipped with the to-be-treated water circulation apparatus The block block diagram of the sewage treatment apparatus which shows 4th Embodiment of this invention. The block diagram of a sewage treatment apparatus including a membrane separation apparatus that employs an internal pressure filtration system according to a fifth embodiment of the present invention Block configuration diagram of a sewage treatment apparatus including a membrane separation apparatus that employs an internal pressure filtration system according to a sixth embodiment of the present invention Block configuration diagram of a sewage treatment apparatus showing a comparative example The block block diagram of the sewage treatment apparatus which shows the modification of 4th Embodiment of this invention. The block block diagram of the sewage treatment apparatus which shows 7th Embodiment of this invention.

  The sewage treatment apparatus and the sewage treatment method according to the first embodiment of the present invention will be described below.

  As shown in FIG. 1, a sewage treatment apparatus 1 includes a biological treatment apparatus 10 that decomposes filth contained in sewage (raw water) such as domestic wastewater and factory effluent, and uses the sewage as biologically treated water. The membrane treatment apparatus 20 which permeate | transmits the biological treatment water by which the waste material was decomposed | disassembled in 10 to a filtration membrane, and isolate | separates this biological treatment water into the concentration treatment water and filtration water containing a waste material, and this concentration treatment water is made into a solid liquid There are provided solid-liquid separation devices 30 and 40 for separation, and circulation devices 6 and 7 for circulating the separated water separated by the solid-liquid separation devices 30 and 40 to the biological treatment device 10.

  The biological treatment device 10, the membrane filtration device 20, and the solid-liquid separation devices 30 and 40 are configured as separate processing blocks.

  The biological treatment apparatus 10 is an apparatus that employs a biofilm method in which sewage is brought into contact with a substrate on which microorganisms are supported, and filth contained in the sewage is biochemically decomposed and purified.

  FIG. 2 shows a rotating disk type biological treatment apparatus which is an example of the biological treatment apparatus 10 employing the biofilm method. The biological treatment apparatus 10 covers a processing tank body 13 made of concrete or metal, a plurality of rotating disc bodies 11 as a base material provided inside the processing tank body 13, and an upper portion of the processing tank body 13. In this way, a lid 14 made of resin or metal is detachably provided on the treatment tank main body 13.

  An inlet connected to the water injection pipe 15 for dirty water (raw water) is provided on one side of the treatment tank body 13, and an outlet for draining biologically treated water obtained by the treatment is provided on the other side. The outlet is connected to the drain pipe 4. The treatment tank body 13 is filled with about half of the sewage. The supplied sewage contains filth. Examples of the filth include surfactants derived from human waste and detergents.

  The rotating disk body 11 is made of a high-density polyethylene, polystyrene, or the like, in which a plate material is formed into a disk, or a fiber is entangled in a steel wool shape and formed into a disk shape. Each of the rotating disk bodies 11 is fitted and fixed at the central portion of the rotating shaft 12 having a prismatic shape, and is arranged along the longitudinal direction of the processing tank main body 13. The rotary shaft 12 is pivotally supported at both ends of the treatment tank main body 13, and one end side is connected to the output shaft of the electromagnetic motor 16.

  In the processing tank main body 13, the rotating disk body 11 is immersed in sewage by about 40% to 70%. In addition, dirt, moss, algae, or mud adheres to the surface and the inside of the rotating disk body 11, and a plurality of types of microorganisms propagate and live there. Thereby, the rotating disk 11 carries microorganisms. Of course, microorganisms also live in the sewage stored in the treatment tank body 13. Examples of the microorganism include bacteria, fungi, microalgae, protozoa and micrometazoans. In addition, examples of protozoa include flagellates, fleshly worms, and ciliates. Examples of minute metazoans include rotifers, nematodes, and oligochaetes.

  When the rotating disk 11 is rotationally driven by the electromagnetic motor 16 at a low speed, microorganisms adhered and propagated on the rotating disk 11 come into contact with the sewage, and organic matter contained in the sewage biochemically. Disassembled. As the rotating disk 11 rotates, these microorganisms absorb oxygen from the air in the upper part of the treatment tank and also absorb pollutants such as filth from the sewage and aerobically decompose. As a result, the filth is decomposed to some extent, and biologically treated water that is cleaner than the sewage is generated. The microorganisms whose activity has declined are removed from the rotating disk body 11 together with mud and algae by the shearing force generated by the rotation of the rotating disk body 11, and are discharged from the drain pipe 4 together with the biologically treated water.

  Returning to FIG. 1, when sewage from the sewage generation source is sent to the treatment tank body 13 via the water pipe 2 by the water pump 3, organic substances contained in the sewage by the microorganisms supported on the rotating disk 11 described above. The biologically treated water after the treatment is sent from the drain pipe 4 to the membrane filtration device 20. In addition, when the amount of sewage from the sewage generation source fluctuates, a sewage storage tank that stores raw water is provided upstream of the water supply pipe 2, and the sewage stored in the sewage storage tank by the water supply pump 3 is treated with the treatment tank body 13. You may comprise so that fixed quantity water supply may be carried out.

  The membrane filtration device 20 cleans the outer surface of the so-called external pressure filtration type hollow fiber membrane 21 that performs filtration from the membrane outer surface to the membrane inner surface, the suction pump 23 that sucks filtered water, and the outer surface of the hollow fiber membrane 21. The aeration apparatus 25, the blower 24 that supplies air to the aeration apparatus 25, and a housing that houses the hollow fiber membrane 21 and the aeration apparatus 25 are provided.

  The casing has a container shape, and an inlet connected to the drain pipe 4 is provided on one side surface, and an outlet connected to the water supply pipe 5 is provided on the other side surface. Biologically treated water containing filth is sent through the drain pipe 4 into the housing. Here, the filth contained in the biologically treated water includes filth that cannot be decomposed by the biological treatment apparatus 10, mud and microorganisms that have been peeled off from the rotating disk 11.

  The hollow fiber membrane 21 is a constituent member of a known membrane module. The hollow fiber membrane 21 is a cylindrical body made of polyvinylidene fluoride (outer diameter: 1 mm, inner diameter: 0.6 mm), and a large number of pores having a diameter of about 0.02 to 0.4 μm are opened on the side wall. The membrane module further includes a header and a skirt that bundle a number of hollow fiber membranes. The skirt seals one end of the hollow fiber membrane. The header is provided with an outlet for taking out filtered water, and the outlet communicates with the internal space of each hollow fiber membrane. The membrane module is housed in the housing of the membrane filtration device 20 filled with biologically treated water, and the biologically treated water is in contact with the outer surface of each hollow fiber membrane.

  The biologically treated water sent to the membrane filtration device 20 is suction filtered through the hollow fiber membrane 21 by the suction pump 23 and extracted, and filtered water, that is, treated water purified at high quality is taken out from the outlet of the header.

  The solid-liquid separation device includes a coagulation sedimentation tank 30 and a dehydrator 40. The coagulation sedimentation tank 30 includes a stirring mechanism 31 including a screw for stirring the liquid stored in the tank and a motor for rotating the screw. Moreover, the inlet connected with the water pipe 5 is provided in the upper part. Biologically treated water in which filth is concentrated without being filtered by the membrane filtration device 20, that is, concentrated treated water, is sent to a coagulating sedimentation tank 30 as a coagulating device through a water pipe 5.

  An inorganic flocculant such as a sulfuric acid band or polyaluminum chloride, a polyacrylamide polymer flocculant, or the like is added to the concentrated treated water sent to the coagulation sedimentation tank 30 at an appropriate timing, and is stirred by the stirring mechanism 31. After that, it is precipitated. The precipitate condensed thereby is fed into the dehydrator 40.

  The dehydrator 40 solid-liquid separates the precipitate into a solid, that is, a dehydrated cake and separated water. The resulting dehydrated cake is discarded. The separated water is circulated and supplied to the water supply pipe 2 by a circulation device including a water supply pump 7 and a circulation water supply pipe 6. One end of the circulation water pipe 6 is connected to the drain of the dehydrator 40, and the other end is connected to the water pipe 2.

  As the dehydrator 40, a centrifugal dehydrator, a screw press dehydrator, a belt press dehydrator, a filter press dehydrator, or the like can be used.

  The biologically treated water that has been biologically treated by the biological treatment apparatus 10 includes fine solids produced by metabolic action by microorganisms and viscous substances such as alginate. When such biologically treated water is supplied to the membrane filtration device 20 as the final stage of the treatment system and subjected to filtration treatment, the biologically treated water in the membrane filtration device 20 becomes minute and viscous as the filtration treatment proceeds. As a result, the filtration performance is significantly reduced due to the contact of the viscous material with the membrane surface.

  Therefore, in the present embodiment, the concentration of biologically treated water in the membrane filtration device 20 is reduced by draining the concentrated biological treatment water supplied to the membrane filtration device 20 from the membrane filtration device 20. It is configured so that a stable filtration performance can be secured.

  Fine solids and viscous substances contained in the biologically treated water concentrated by the membrane filtration device 20 are precipitated in the coagulation sedimentation tank 30 and separated and removed as solid components by the dehydrator 40. The concentration of minute solids and viscous substances contained in the separated water circulated and supplied to the biological treatment device 10 is extremely low, and the minute solids and viscosity of biological treatment water sent from the biological treatment device 10 to the membrane filtration device 20 are low. The concentration of the substance is maintained at a low state, and as a result, stable filtration performance is maintained. It should be noted that the amount of removal of viscous substances and the like in the solid-liquid separators 30 and 40 may be greater than or equal to the amount of increase in viscous substances and the like in the biological treatment apparatus 10.

  Compared with the activated sludge method, the biological treatment method using a substrate on which microorganisms are supported is characterized by being less affected by environmental changes and producing less dehydrated cake. This is because the microorganisms are fixed on the base material, making it difficult for the microorganisms to flow out, resulting in a longer food chain of microorganisms (ie, a large number of different microorganisms inhabiting) and promoting the decomposition of filth. Is the reason. However, a microorganism-derived viscous substance is used to support microorganisms, and this causes a negative influence on membrane filtration by dissolving in biologically treated water.

  Therefore, the sewage purification method according to the present invention includes a biological treatment step of obtaining biologically treated water from sewage by bringing the sewage into contact with a substrate on which microorganisms that decompose filth contained in sewage are carried to decompose the filth, and A membrane filtration step that permeates biological treated water through a filtration membrane and physically separates it into concentrated treated water containing filth contained in biological treated water and filtered water, and solid-liquid separation of treated water containing at least concentrated treated water And a solid-liquid separation step. Furthermore, it is preferable to provide a circulation step for circulating the separated water separated in the solid-liquid separation step to the biological treatment step.

  FIG. 8 shows a comparative example with the sewage treatment apparatus 1 according to the present invention. Solid-liquid separators 30 and 40 are arranged between the biological treatment apparatus 10 and the membrane filtration apparatus 20, and the supernatant liquid (biologically treated water) of the coagulation sedimentation tank 30 is transferred to the membrane filtration apparatus 20 as the final stage of the treatment system. The difference is that it is supplied. In the sewage treatment apparatus 1 ′ according to the comparative example, since there is no mechanism for discharging filth such as viscous substances from the biological treatment water concentrated by the membrane filtration apparatus 20, a minute amount contained in the biological treatment water staying in the membrane filtration apparatus 20. The concentration of substances and viscous substances increases, and the amount of permeated water in membrane filtration cannot be kept high.

  FIG. 3 shows a second embodiment of the sewage treatment apparatus 1 according to the present invention. In addition to the sewage treatment apparatus of the first embodiment, a measurement device 51 that measures a membrane clogging index in the membrane filtration device 20 using biologically treated water treated by the biological treatment device 10, and a membrane clogging measured by the measurement device 51 A control device 50 that adjusts the amount of circulating water by the circulation device based on the index is provided.

  Since the circulation amount of the separated water by the water supply pump 7 is adjusted by the control device 50 so that the measured film clogging index is maintained within a predetermined range, even if the amount of generated sewage and the properties vary, The concentration of viscous substances and the like contained in the biologically treated water sent from the biological treatment device 10 to the membrane filtration device 20 can be maintained in a low state.

  For example, as a measuring device 51 for measuring a film clogging index, the rotational speed of a rotor is controlled to be constant or variable, and a viscometer based on a rotational speed control system that detects torque, the rotor is rotated by torque control, and how much is rotated In addition, it is possible to use a viscometer based on a stress control system that detects how much micro deformation occurs.

  Further, as the measuring device 51, a densitometer that measures the concentration of minute substances in the biologically treated water can be used. For example, a densitometer that measures the solid concentration using light such as ultraviolet rays, electromagnetic waves, or ultrasonic waves can be used. In the case where the minute matter that causes membrane clogging of the filtration membrane has a specific particle size distribution, a particle size distribution measuring device using a light scattering phenomenon can be used.

  When the concentration of the viscous substance in the biologically treated water has a correlation with the concentration of the minute matter, a concentration meter that measures the concentration of the minute matter in the treated water may be used instead of the viscometer.

  In any case, any measuring device 51 may be used as long as it can measure a membrane clogging index in the membrane filtration device 20 due to minute matters or viscous substances contained in biologically treated water.

  The control device 50 described above functions as a device that prevents film clogging based on the film clogging index measured by the measuring device 51. As a device for preventing membrane clogging, instead of the above-described control device 50, when the membrane clogging index becomes higher than a predetermined threshold based on the membrane clogging index measured by the measuring device 51, it stays in the membrane filtration device 20. You may provide the control apparatus which discharges the whole quantity or fixed quantity of concentration process water to the solid-liquid separation apparatuses 30 and 40 intermittently.

  As the filtration proceeds, the concentration of fines and viscous substances contained in the concentrated treated water staying in the membrane filtration device 20 increases, so that the total amount or a fixed amount of the concentrated treated water is intermittently separated into the solid-liquid separation devices 30, 40. The membrane clogging can be prevented by reducing the concentration of fine substances and viscous substances contained in the concentrated treated water staying in the membrane filtration device 20 by being discharged into the membrane.

  The specific configuration of the apparatus for preventing membrane clogging is not limited to the above-described one, and when the membrane clogging index becomes higher than a predetermined threshold based on the membrane clogging index, You may provide the control apparatus which supplies the dilution water which reduces the density | concentration of a viscous substance to the downstream of the biological treatment apparatus 10, or the water distribution pipe 4. FIG. As the dilution water, the supernatant of the coagulation sedimentation tank 30 or the separated water of the dehydrator 40 can be used.

  FIG. 4 shows a third embodiment of the sewage treatment apparatus 1 according to the present invention. As shown in FIG. 1, the sewage treatment apparatus 1 described above includes solid-liquid separation apparatuses 30 and 40 that take out concentrated treated water from the membrane filtration apparatus 20 and perform solid-liquid separation, and solid-liquid separation apparatuses 30 and 40. Although it is the structure provided with the circulators 6 and 7 which circulate the separated to-be-processed water to the biological treatment apparatus 10, it does not have the circulators 6 and 7, but coagulate-precipitates a viscous substance and a micro thing with the coagulation sedimentation tank 30. This is an example of utilizing the supernatant liquid (biologically treated water) as reused water. 4 does not show the dehydrator 40, the dehydrator 40 may be provided.

  Although the water quality of the supernatant liquid of the coagulation sedimentation tank 30 is lower than that of the water to be treated filtered by the membrane filtration device 20, it is purified to the extent that it can be discharged into the river. It can be reused for a predetermined use such as a water source.

  FIG. 5 shows a fourth embodiment of the sewage treatment apparatus 1 according to the present invention. In this embodiment, solid-liquid separation devices 30 and 40 are disposed between the biological treatment device 10 and the membrane filtration device 20. The biologically treated water discharged from the biological treatment apparatus 10 is supplied to the coagulation sedimentation tank 30 through the drain pipe 4. As described above, in the coagulation sedimentation tank 30, viscous substances and fine substances are precipitated, and the supernatant (biologically treated water) of the coagulation sedimentation tank 30 is supplied to the membrane filtration device 20 via the water supply pipe 5. When this configuration is adopted, it is preferable to provide a return pipe 9 a that returns the concentrated treated water concentrated by the membrane filtration device 20 to the biological treatment device 10.

  The biologically treated water concentrated in the membrane filtration device 20 and having a high concentration of viscous substances or the like is returned to the biological treatment device 10 via the return pipe 9a and mixed with the biologically treated water biologically treated in the biological treatment device 10. The concentrated treated water is indirectly sent to the solid-liquid separators 30 and 40. That is, the treated water containing at least the concentrated treated water is solid-liquid separated by the solid-liquid separators 30 and 40. In addition, since there are the solid-liquid separation devices 30 and 40 in the previous stage of the membrane filtration device 20, most viscous substances and the like are removed here. Therefore, the concentration of viscous substances and the like contained in the supernatant (biologically treated water) is low in the first place, and although the supernatant is concentrated by the membrane filtration device 20, the concentration is absolutely low. Therefore, even if the supernatant concentrated in the membrane filtration device 20 is returned to the biological treatment device 10 through the return pipe 9a, the concentration of viscous substances and the like does not increase.

  Separation water in which the concentration of the viscous substance is reduced by the solid-liquid separation process in the coagulation sedimentation tank 30 and the dehydrator 40 is circulated and supplied to the biological treatment apparatus 10 by the circulation devices 6 and 7. In addition, it replaces with the path | route which returns the concentrated treated water concentrated by the membrane filtration apparatus 20 to the downstream of the biological treatment apparatus 10 via the return pipe 9a, and as shown by the broken line in FIG. You may provide the return pipe 9b returned to the upstream of the processing apparatus 10. FIG. Specifically, the return pipe 9 b and the circulation water pipe 6 may be connected, and one end of the circulation water pipe 6 may be connected to the water pipe 2.

  Even when configured in this way, the concentration of viscous substances and the like in the biologically treated water sent to the membrane filtration device 20 is maintained in a low state, and as a result, stable filtration performance is maintained.

  Furthermore, in this embodiment, it is also possible to constitute so that the concentrated treated water is directly sent to the solid-liquid separators 30 and 40 without going through the biological treatment apparatus 10. As shown in FIG. 9, it is included in the biological treatment water supplied to the membrane filtration device 20 by providing the circulation devices 60 and 70 for circulating the biological treatment water staying in the membrane filtration device 20 to the coagulation sedimentation tank 30 in the previous stage. It is possible to effectively suppress the increase in the concentration of minute substances and viscous substances.

  That is, a biological treatment process for obtaining biologically treated water from wastewater by bringing wastewater into contact with a substrate on which microorganisms that decompose the waste contained in the wastewater are carried and decomposing the waste, and at least a living thing obtained in the biological treatment process A solid-liquid separation step for solid-liquid separation of the treated water containing the treated water, a permeated supernatant liquid through the filtration membrane in the solid-liquid separation step, and a concentrated treated water containing the filth contained in the supernatant and filtered water; And a sewage purification method comprising a membrane filtration step of physically separating the sewage.

  FIG. 6 shows a fifth embodiment of the sewage treatment apparatus 1 according to the present invention. In this embodiment, the example which employ | adopts the membrane filtration apparatus 20 provided with the hollow fiber membrane 21 of what is called an internal pressure filtration system which filters from the membrane inner surface to the membrane outer surface is shown.

  The membrane filtration device 20 is provided with an inlet connected to the drain pipe 4 on one side surface of the cylindrical casing, and an outlet connected to the water supply pipe 5 on the other side surface. The membrane module includes a pair of headers for bundling a large number of cylindrical hollow fiber membranes at both ends, and biologically treated water containing filth fed from an inlet is guided into the hollow fiber membrane from one header, and from the other header. It is drained into the water pipe 5 through the outlet. A suction pump 23 is connected to a drain pipe formed on the side of the housing.

  The biologically treated water biologically treated by the biological treatment device 10 is pumped to the inner surface side of the hollow fiber membrane 21 of the membrane filtration device 20 by the water pump 8 provided in the water pipe 4, and sucked from the inner surface of the membrane to the outer surface of the membrane by the suction pump 23. Filtered filtered water is removed.

  The concentrated treated water that has passed through the inner surface of the hollow fiber membrane 21 is returned to the downstream side of the biological treatment apparatus 10 via the drain pipe 5, and together with the biologically treated water biologically treated by the biological treatment apparatus 10, the solid-liquid separation device 30, The water is sent to 40 for solid-liquid separation.

  The separated water that has been separated into solid and liquid by the dehydrator 40 and reduced in the concentration of the viscous substance is circulated and supplied to the upstream side of the biological treatment device 10 by the circulation devices 6 and 7, so that the biological treatment sent to the membrane filtration device 20 The concentration of viscous substances and the like contained in water is suppressed to a low state.

  In the case of adopting the membrane filtration device 20 of the internal pressure filtration method, it is not necessary to provide the membrane cleaning aeration device 25 and the blower 24. Therefore, further space saving and cost reduction of the sewage treatment device 1 can be achieved. it can.

  FIG. 7 shows a sixth embodiment of the sewage treatment apparatus 1 according to the present invention. In the present embodiment, another example is shown in which a membrane filtration device 20 including an internal pressure filtration type hollow fiber membrane 21 is employed. Similar to FIG. 6, the biologically treated water biologically treated by the biological treatment device 10 is pumped to the inner surface side of the hollow fiber membrane 21 of the membrane filtration device 20 by the water pump 8 provided in the water feed pipe 4, and the membrane is sucked by the suction pump 23. The filtered water that has been suction filtered from the inner surface to the outer surface of the membrane is taken out.

  Concentrated treated water that has passed through the inner surface of the hollow fiber membrane 21 is sent to the solid-liquid separators 30 and 40 through the drain pipe 5, and the separated liquid is separated from the biological treatment apparatus 10 by the circulation devices 6 and 7. Circulated and supplied upstream. Therefore, also in this case, the concentration of viscous substances and the like contained in the biologically treated water sent to the membrane filtration device 20 is suppressed to a low state.

  In the embodiment described above, the coagulation sedimentation tank 30 and the dehydrator 40 are provided as the solid-liquid separator, and the separated water separated by the dehydrator 40 is circulated and supplied to the biological treatment apparatus 10 by the circulation devices 6 and 7. As described above, since the viscous substance contained in the biologically treated water is coagulated and precipitated to some extent in the coagulation sedimentation tank 30, in addition to the separated water from the dehydrator 40, the supernatant of the coagulation sedimentation tank 30 is circulated by the circulation device 6. , 7 can be circulated and supplied to the biological treatment apparatus 10. Further, the supernatant of the coagulation sedimentation tank 30 can be circulated and supplied to the biological treatment apparatus 10 by the circulation devices 6 and 7 without providing the dehydrator 40. Also in this case, it is needless to say that the supernatant is a concept included in the separated water that has been solid-liquid separated by the solid-liquid separation device.

  FIG. 10 shows a seventh embodiment of the sewage treatment apparatus 1 according to the present invention. This embodiment is also an example suitable for the case where the membrane filtration device 20 including the hollow fiber membrane 21 of the internal pressure filtration method is employed. The biologically treated water biologically treated by the biological treatment apparatus 10 is discharged to the coagulation sedimentation tank 30 through the water supply pipe 4, and the supernatant liquid of the coagulation sedimentation tank 30 is transferred to the hollow fiber membrane 21 of the membrane filtration apparatus 20 by the water supply pump 8. The filtered water pumped to the inner surface side and suction filtered from the inner surface of the membrane to the outer surface of the membrane by the suction pump 23 is taken out.

  The concentrated treated water that has passed through the inner surface of the hollow fiber membrane 21 is circulated to the coagulation sedimentation tank 30 via the drain pipe 5, and the separated water separated by the dehydrator 40 is upstream of the biological treatment apparatus 10 by the circulation devices 6 and 7. Circulated to the side.

  In the embodiment described above, a rotating disk type in which 40% to 70% is immersed in the sewage in the treatment tank main body 13 and the sewage is aerobically processed by the microorganisms supported on the rotating disk 11 that rotates at a low speed. Although the sewage treatment apparatus 1 provided with the biological treatment apparatus 10 has been described, 100% of the sewage treatment apparatus 10 is immersed in sewage in the main body of the treatment tank and is carried on the rotation disk body 11 in the front stage of the rotation disk type biological treatment apparatus 10. Dual rotating disk type biological treatment device that treats sewage anaerobically with anaerobic microorganisms, anaerobic treatment of sewage with the previous biological treatment device, and aerobic treatment of sewage with the subsequent biological treatment device The biological treatment apparatus may be provided.

  In the case where two biological treatment apparatuses are provided, the separated water from which the dehydrated cake has been separated by the solid-liquid separation apparatuses 30 and 40 is preferably circulated and supplied to the biological treatment apparatus 10 that is aerobically treated by the circulation apparatus.

  Although any embodiment mentioned above demonstrated the example which employ | adopted the rotation disk type biological treatment apparatus 10 as the sewage treatment apparatus 1, the biological treatment apparatus employ | adopted for the sewage treatment apparatus 1 by this invention is a rotation disk type biological treatment apparatus. It is not limited to the treatment apparatus 10, and other methods may be adopted as long as the biological treatment apparatus adopts a biofilm method in which the role of floc in the activated sludge method is made to function by a biofilm attached to the contact material. Is possible. For example, contact aeration method, entrapping immobilization method, self-granulation method and the like.

  Although any embodiment mentioned above demonstrated the example which employ | adopted the membrane filtration apparatus 20 provided with the hollow fiber membrane in the sewage treatment apparatus 1, the film | membrane used for the membrane filtration apparatus 20 employ | adopted for the sewage treatment apparatus 1 by this invention. In addition to the hollow fiber membrane, other shapes of filtration membranes such as a spiral membrane, a tubular membrane, and a flat membrane can be adopted. The type of membrane such as a microfiltration membrane and an ultrafiltration membrane can be appropriately selected depending on the application. Furthermore, a reverse osmosis membrane can be used when it is necessary to obtain filtered water with extremely high purity. Further, the filtration direction such as an external pressure type and an internal pressure type can be selected as appropriate, and the suction pump can be omitted.

  Each of the above-described embodiments is merely an example of the present invention, and within the scope of the effects of the present invention, the capacity of the biological treatment device, the membrane filtration device, the solid-liquid separation device, the material of each member constituting each device, and each It goes without saying that the specific configuration such as the arrangement of the apparatus can be changed and designed as appropriate.

1: Sewage purification device 6: Circulation device (circulation water pipe)
7: Circulation device (water pump)
10: Biological treatment device 11: Rotating disk 12: Rotating shaft 13: Treatment tank body 14: Cover 15: Water injection pipe 16: Electromagnetic motor 20: Membrane filtration device 30: Solid-liquid separator (coagulation sedimentation tank)
40: Solid-liquid separator (dehydrator)
50: Control device 51: Measuring device

Claims (10)

  A biological treatment device that obtains biologically treated water from the wastewater by bringing the wastewater into contact with a substrate carrying microorganisms that decompose the waste contained in the wastewater, and the biologically treated water as a filtration membrane A membrane filtration device that permeates and physically separates the concentrated treated water containing the filth contained in the biological treated water and the filtered water, and a solid-liquid separation device that separates at least the treated water containing the concentrated treated water into a solid-liquid separation And a sewage purification device.   The solid-liquid separation device is supplied with the concentrated treated water discharged from the membrane filtration device, agglomerates the aggregated solid dispersion in the concentrated treated water to separate the aggregates, and the aggregates into solids The sewage purification apparatus according to claim 1, comprising a dehydrator that separates the water into separated water.   A biological treatment apparatus for obtaining biologically treated water from the sewage by bringing the sewage into contact with a substrate on which microorganisms for degrading filth contained in the sewage are supported, and solid dispersion in the biologically treated water A solid-liquid separation device that separates the solid and liquid, and the treated water that has been solid-liquid separated by the solid-liquid separation device is permeated through a filtration membrane to obtain concentrated treated water containing filth contained in the biological treated water and filtered water. A sewage purification apparatus comprising a membrane filtration device for physical separation.   The solid-liquid separation device is supplied with the concentrated treated water discharged from the membrane filtration device and the biological treated water discharged from the biological treated device, and is a solid in the mixed water of the concentrated treated water and the biological treated water. The sewage purification apparatus according to claim 1 or 3, wherein the dispersion is subjected to solid-liquid separation, and treated water that is solid-liquid separated by the solid-liquid separation apparatus is supplied to the membrane filtration apparatus.   The sewage purification apparatus according to any one of claims 1 to 4, further comprising a circulation device for circulating the separated water separated by the solid-liquid separation device to the biological treatment device.   The sewage purification apparatus according to claim 5, further comprising a circulation device for circulating the concentrated treated water discharged from the membrane filtration device to the biological treatment device.   Membrane clogging is prevented on the basis of a measuring device that measures a membrane clogging index in the membrane filtration device by the biologically treated water or the solid-liquid separated treated water, and a membrane clogging indicator measured by the measuring device. The sewage purification apparatus according to any one of claims 1 to 6, further comprising an apparatus.   A measuring device for measuring a membrane clogging index in the membrane filtration device by the biologically treated water or the treated liquid separated into solid and liquid, and circulation by the circulation device based on the membrane clogging index measured by the measuring device The sewage purification apparatus of Claim 5 or 6 provided with the control apparatus which adjusts the amount of water.   A biological treatment step of obtaining biologically treated water from the sewage by bringing the sewage into contact with a substrate on which microorganisms that decompose the filth contained in the sewage are supported and decomposing the filth, and the biologically treated water as a filtration membrane A membrane filtration step that permeates and physically separates the concentrated treated water containing the filth contained in the biological treated water and the filtered water, and a solid-liquid separation step that solid-liquid separates the treated water containing at least the concentrated treated water. And a sewage purification method.   A biological treatment step of obtaining biologically treated water from the wastewater by bringing the wastewater into contact with a substrate carrying microorganisms that decompose the waste contained in the wastewater, and a treatment including at least the biologically treated water A solid-liquid separation step for separating water into solid and liquid, and allowing the supernatant liquid in the solid-liquid separation step to permeate through a filtration membrane, and physically treating the concentrated treated water containing filth contained in the supernatant and filtered water. A sewage purification method comprising a membrane filtration step for separating the sewage.

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