JP2013240794A - Membrane separation activated sludge treatment apparatus, and membrane separation activated sludge treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane separation activated sludge treatment apparatus capable of markedly enhancing filtering efficiency, capable of suppressing the damage and contamination of a filter membrane and improved in waste water treatment efficiency.SOLUTION: A membrane separation activated sludge treatment apparatus 1 includes a biological treatment part 2 for mixing flocculated sludge formed by a biological flocculation means, and a purified treated water forming part 3 for obtaining purified treated water by membrane filtration. The biological treatment part 2 has a biological flocculation tank 24 for forming the flocculated sludge by the biological flocculation means, and a sludge-containing biologically treated water storage tank 21 for mixing the formed flocculated sludge and waste water to form mixed water and biologically treating the mixed water to obtain sludge-containing biologically treated water. The non-permeated water formed by a membrane unit 31 is more concentrated in the flocculated sludge as compared with the sludge-containing biologically treated water in the sludge-containing biologically treated water storage tank 21. A means for transferring the non-permeated water to the biological flocculation tank 24 is also provided.

Description

  The present invention relates to a membrane separation activated sludge treatment apparatus and a membrane separation activated sludge treatment method.

  Conventionally, a membrane separation activated sludge treatment apparatus has a biological treatment unit that mixes waste water and activated sludge and biologically processes to form a sludge-containing biological treatment water, and a membrane unit that performs membrane filtration, and the sludge-containing organism. Since it is provided with a purified treated water generating unit that obtains purified treated water that is permeated by membrane filtration from the treated water, it is used for the treatment of wastewater containing organic substances and the like as an application (for example, Patent Document 1). .

  However, in such a membrane separation activated sludge treatment apparatus, the filtration membrane is clogged with activated sludge, and there is a possibility that the filtration efficiency is lowered or the filtration membrane is damaged. In particular, when the filtration membrane is damaged, there is a problem that the cost for replacing the filtration membrane is increased. In order to suppress such clogging, the filtration membrane is aerated, but energy for aeration is required. Also, if such clogging occurs, reverse the flow of water in the membrane unit and wash water (water that is cleaner than waste water or contains chemicals such as acids, alkalis, and oxidants). It is necessary to frequently take measures such as washing the activated sludge clogged in the filtration membrane or aeration of the filtration membrane, and there is a risk that it may take time and effort. There is also a risk that wastewater treatment must be interrupted frequently. Further, if the filtration membrane is clogged or frequently washed, there is a problem that the speed of collecting the permeate decreases. Furthermore, if cleaning is frequently performed, there is a problem that the energy cost increases for cleaning. Thus, the conventional membrane separation activated sludge treatment apparatus has a problem that the efficiency of wastewater treatment is poor.

  In order to cope with such a problem, a membrane separation activated sludge treatment apparatus that makes activated clogging with a flocculant to increase the particle size and makes it difficult to clog the membrane is disclosed (for example, Patent Document 2). Further, a membrane separation activated sludge treatment apparatus using activated sludge that aggregates activated sludge using a granular carrier such as plastic as a core and floats with this carrier is also disclosed (for example, Patent Document 3).

JP 2007-289941 A JP 2006-15236 A JP-A-9-308883

  However, when activated sludge is flocculated only with a flocculant as in Patent Document 2, if there is too little flocculant, the activated sludge is not sufficiently agglomerated, and clogging of the membrane due to activated sludge can hardly be suppressed. On the other hand, if the amount of the flocculant is too large, the flocculant itself is clogged with the film, which may damage the film. Moreover, since activated sludge can increase in the process of wastewater treatment, it is necessary to add a flocculant according to the increase of activated sludge, and there is a problem that the cost of the flocculant increases.

  In addition, as in Patent Document 3, when activated sludge is used which aggregates activated sludge using a granular fluid carrier such as plastic as a core and floats with this carrier, the carrier comes into contact with the filtration membrane, and the filtration membrane There is a risk of damage. Moreover, since the activated sludge which floats without aggregating remains, the problem similar to patent document 1 still remains.

  In view of the above problems, the present invention is to provide a membrane separation activated sludge treatment apparatus that can remarkably improve filtration efficiency, suppress filtration membrane damage and contamination, and has good wastewater treatment efficiency. And Another object of the present invention is to provide a membrane separation activated sludge treatment method that can significantly improve the filtration efficiency, suppress the damage and contamination of the filtration membrane, and have good wastewater treatment efficiency.

  In the present invention, activated sludge is biologically agglomerated to produce an agglomerated sludge body. The agglomerated sludge body produced by a biocoagulation means and waste water are mixed to produce mixed water, and the mixed water is biologically treated to contain sludge. A biological treatment unit that obtains biologically treated water, and a purified treated water generation unit that has a membrane unit that performs membrane filtration and obtains purified treated water that is permeated by membrane filtration from the sludge-containing biologically treated water. It is in the membrane separation activated sludge treatment equipment characterized.

  According to such a membrane separation activated sludge treatment apparatus, since the aggregated sludge body is aggregated, adhesion to the filtration membrane and clogging of the filtration membrane are less likely to occur. Moreover, damage to a filtration membrane can be suppressed because the aggregate sludge is produced by the biological aggregation means. As a result, the present invention can improve the filtration efficiency, further suppress the damage of the filtration membrane and extend the life of the filtration membrane as compared with the prior art. Therefore, there is an effect that it is possible to reduce the amount of aeration for reducing the energy cost for cleaning.

  In the membrane-separated activated sludge treatment apparatus according to the present invention, preferably, the biological aggregating means is produced by aggregating the activated sludge with a carrier and separating the agglomerated sludge body from the carrier.

  According to such a membrane separation activated sludge treatment apparatus, the aggregated sludge body is formed by being separated from the carrier, so that the carrier itself and the filtration membrane can be prevented from contacting each other, and the filtration membrane is damaged. There is an advantage that can be further suppressed. Further, since the aggregated sludge body can be generated many times from one carrier, there is an advantage that the activated sludge is easily aggregated as compared with the conventional carrier (fluid carrier).

  Further, the membrane separation activated sludge treatment apparatus adopting the bioaggregation means that is produced by aggregating the activated sludge with a carrier and separating the agglomerated sludge body from the carrier is preferably aerated in the biological treatment unit. An aeration means is provided, the carrier is disposed so as to be separated from the membrane unit, and includes an adhering body to which the activated sludge is adhered, and a support portion for supporting the adhering body, and the aeration The adhering body is configured to swing by aeration by means.

  According to such a membrane separation activated sludge treatment apparatus, there is an advantage that an agglomerated sludge body can be easily generated.

  In the membrane separation activated sludge treatment apparatus according to the present invention, preferably, the aggregated sludge body has a particle size of 1 μm to 10 mm.

  According to such a membrane separation activated sludge treatment apparatus, since the aggregated sludge has a particle size of 1 μm or more, the aggregated sludge tends to settle and the mixed water is easily separated into solid and liquid. There is an advantage that clogging can be made difficult to occur. Moreover, when the particle size of the aggregated sludge body is 10 mm or less, there is an advantage that the clogging between the filtration membranes due to the aggregated sludge body can be suppressed.

  The particle size of the aggregated sludge body is an arithmetic average value (the number of samples: 100 or more) of the length of the longest portion measured with a microscope for the particles constituting the aggregate of the aggregated sludge body.

  Furthermore, in the membrane-separated activated sludge treatment apparatus according to the present invention, preferably, the purified treated water generation unit causes the sludge-containing biological treated water to be agglomerated sludge from the sludge-containing biologically treated water by gravity sedimentation of the aggregated sludge. A gravity sedimentation tank that produces a more concentrated sludge concentrated water and a supernatant water having a content of agglomerated sludge body than that of the sludge-containing biologically treated water, and the membrane unit membrane-filters the supernatant water. Is configured to generate the purified water.

  According to such a membrane separation activated sludge treatment apparatus, since the aggregated sludge body can be easily settled, supernatant water can be easily formed, and by filtering the supernatant water through a membrane unit, There is an advantage that clogging of the filtration membrane can be further suppressed. Therefore, the frequency of cleaning the filtration membrane and the amount of aeration for cleaning the membrane can be reduced.

  The membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified treated water by subjecting the supernatant water to membrane filtration, preferably, the membrane unit includes: The immersion film is installed below the liquid level in the gravity settling tank.

  According to such a membrane separation activated sludge treatment apparatus, there are advantages that the structure of the apparatus is simplified and the apparatus can be miniaturized.

  Furthermore, the membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified treated water by subjecting the supernatant water to membrane filtration is preferably the gravity sedimentation tank. The supernatant unit is provided with a supernatant water storage tank for storing the supernatant water, and the membrane unit is installed as a submerged membrane below the liquid surface in the supernatant water storage tank.

  According to such a membrane separation activated sludge treatment apparatus, even when the aggregated sludge body contained in the sludge concentrated water in the gravity sedimentation tank floats in the supernatant water, the floating aggregate sludge body is prevented from coming into contact with the permeable membrane. Therefore, there is an advantage that clogging of the filtration membrane can be further suppressed. In addition, when the filtration membrane is washed with chemicals, it is difficult for the chemicals to be mixed into the sludge-containing biologically treated water storage tank, and there is an advantage that the aggregated sludge body of the sludge-containing biologically treated water storage tank is not easily affected by the chemicals. .

  In addition, the biological separation section is preferably a membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified treated water by subjecting the supernatant water to membrane filtration. The sludge-containing biologically treated water storage tank for storing the sludge-containing biologically treated water produced by the tank is formed, and the sludge-containing biologically treated water storage tank and the gravity settling tank are formed by dividing one tank by a partition plate. Being done.

  According to such a membrane separation activated sludge treatment apparatus, there are advantages that the structure of the apparatus is simplified and the apparatus can be miniaturized.

  Furthermore, the membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified treated water by subjecting the supernatant water to membrane filtration is preferably the gravity sedimentation tank. The bottom portion is provided with a sludge concentrated water discharge port, and the bottom portion is formed in a tapered shape that tapers downward so as to incline toward the sludge concentrated water discharge port.

  According to such a membrane separation activated sludge treatment apparatus, the sludge concentrated water can be easily extracted from the gravity sedimentation tank, and the sludge body of sludge concentrated water can be prevented from rising and contained in the supernatant water. Since the amount of the coagulated sludge body can be suppressed, there is an advantage that the filtration membrane becomes more difficult to clog.

  Further, the membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified water by membrane filtration of the supernatant water is preferably the gravity sedimentation tank. An inclined plate is provided inside.

  According to such a membrane separation activated sludge treatment apparatus, it is possible to prevent the settled aggregate sludge body from rising again, and to suppress the amount of the aggregate sludge body contained in the supernatant water. There is an advantage that clogging is more difficult. In addition, it is easy to reduce the gravity sedimentation tank because it is easy to increase the water area load, or it is easy to lower the separation interface (interface between the supernatant water and sludge concentrated water), so that the installation space for the membrane unit is secured. There is an advantage that becomes easy.

  Furthermore, the membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified treated water by subjecting the supernatant water to membrane filtration is preferably the gravity sedimentation tank. Is provided with a distributor that distributes and supplies the sludge-containing biologically treated water into the tank.

  According to such a membrane separation activated sludge treatment apparatus, purified treatment water can be supplied relatively evenly to the gravity settling tank, and the disturbance of the interface between the sludge concentrated water and the supernatant water is suppressed. The amount of agglomerated sludge mixed in can be suppressed. Therefore, there is an advantage that the filtration membrane becomes more difficult to clog. In addition, it is easier to downsize the gravity sedimentation tank than the gravity sedimentation tank provided with a center well as means for supplying the sludge-containing biologically treated water into the gravity sedimentation tank, or installation of a membrane unit. There is an advantage that space can be easily secured.

  Further, the membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified water by membrane filtration of the supernatant water is preferably the gravity sedimentation tank. However, it comprises swirl supply means for feeding the sludge-containing biologically treated water into the tank while swirling along the inner peripheral surface of the tank.

  According to such a membrane separation activated sludge treatment apparatus, it is possible to suppress the flocculation of the settled aggregate sludge body and to suppress the amount of the aggregate sludge body contained in the supernatant water. There is an advantage that clogging is difficult. Further, since the aggregate sludge body can be easily settled by centrifugal force in addition to gravity, the water area load can be increased and the gravity sedimentation tank can be easily downsized, or the sludge is placed in the gravity sedimentation tank. As compared with a gravity sedimentation tank provided with a center well as means for supplying the biological treatment water, there is an advantage that the gravity sedimentation tank can be easily downsized and the installation space for the membrane unit can be easily secured.

  Furthermore, the membrane separation activated sludge treatment apparatus according to the present invention preferably includes a non-permeation hydroxylation treatment unit that oxidizes organic substances contained in non-permeate water obtained by membrane filtration in the membrane unit. Non-permeated water obtained by oxidizing an organic substance in the hydroxylation unit is configured to be transferred to the biological treatment unit as a part of the mixed water.

  According to such a membrane-separated activated sludge treatment apparatus, a substance (non-degradable substance) that is contained in non-permeate water and is difficult to be decomposed into an aggregated sludge body is easily decomposed into an aggregated sludge body by oxidation (easily degradable substance). It is possible to suppress the fouling by suppressing the accumulation of the hardly decomposable substance until the filter membrane is further clogged.

  Furthermore, the membrane separation activated sludge treatment apparatus comprising the gravity sedimentation tank and configured so that the membrane unit generates the purified treated water by subjecting the supernatant water to membrane filtration, is preferably the supernatant water. It comprises a supernatant hydroxylation treatment section that oxidizes the contained organic matter, and is configured to produce the purified treated water by membrane filtration of the supernatant water that has been subjected to oxidation treatment in the supernatant hydroxylation treatment section. .

  According to such a membrane-separated activated sludge treatment apparatus, a substance (persistently degradable substance) that is contained in supernatant water and is not easily decomposed into agglomerated sludge is easily decomposed into agglomerated sludge by oxidation (easily degradable substance). Since it decomposes | disassembles and it can suppress that a hardly decomposable substance accumulate | stores and fouling can be suppressed, there exists an advantage that it becomes difficult to clog a filtration membrane much more.

  In the membrane-separated activated sludge treatment apparatus according to the present invention, preferably, the purified treated water generation unit concentrates the aggregated sludge body from the sludge-containing biological treated water more than the sludge-containing biological treated water by centrifugal force. A cyclone that produces a sludge-concentrated water and a cyclone-treated water in which the content rate of the coagulated sludge body is less than the sludge-containing biologically treated water, and the membrane unit filters the cyclone-treated water by membrane filtration. Configured to produce water.

  According to such a membrane separation activated sludge treatment apparatus, since the content of the coagulated sludge body contained in the cyclone treated water supplied to the membrane unit is reduced, there is an advantage that the filtration membrane becomes more difficult to clog. is there. Further, since the cyclone requires less space than the gravity sedimentation tank, there is an advantage that the filtration membrane can be made less clogged with less space.

  Furthermore, the membrane separation activated sludge treatment apparatus according to the present invention preferably includes a screen that generates screen treated water from the sludge-containing biological treated water, wherein the content rate of the aggregate sludge body is less than that of the sludge-containing biological treated water, The membrane unit is configured to generate the purified treated water by subjecting the screen treated water to membrane filtration.

  According to such a membrane separation activated sludge treatment apparatus, since the content of the coagulated sludge contained in the screen treated water supplied to the membrane unit is reduced, there is an advantage that the filtration membrane becomes more difficult to clog. is there. In addition, since the screen requires less space than the gravity sedimentation tank, there is an advantage that the filtration membrane can be hardly clogged with less space.

  Further, in the membrane separation activated sludge treatment apparatus according to the present invention, preferably, the biological treatment unit mixes a biocoagulation tank in which the coagulation sludge is produced by the biocoagulation means, and the produced coagulation sludge and wastewater. A sludge-containing biologically treated water storage tank for producing a mixed water and biologically treating the mixed water to obtain a sludge-containing biologically treated water, wherein the non-permeated water generated by the membrane unit contains the sludge Non-permeated water transfer means configured to transfer the non-permeate water to the bio-coagulation tank is configured such that the coagulated sludge body is more concentrated than the sludge-containing biological process water in the bio-treatment water storage tank. It will be.

  According to such a membrane separation activated sludge treatment device, the activated sludge contained in the non-permeated water in which the activated sludge is concentrated is configured to be aggregated, so that the aggregated sludge body can be generated more efficiently. There are advantages. In addition, there is an advantage that the energy for returning the non-permeated water can be used effectively.

  Furthermore, in the membrane separation activated sludge treatment apparatus according to the present invention, preferably, the biological treatment unit mixes the bioflocculation tank in which the coagulation sludge is produced by the biocoagulation means, and the produced coagulation sludge and wastewater. A sludge-containing biologically treated water storage tank for producing a mixed water and biologically treating the mixed water to obtain a sludge-containing biologically treated water. Gravity sedimentation tank that produces sludge concentrated water in which agglomerated sludge body is concentrated from the treated water than the sludge-containing biologically treated water and a supernatant water in which the content rate of the agglomerated sludge body is less than the sludge-containing biologically treated water, or The sludge concentrated water in which the aggregated sludge body is concentrated from the sludge-containing biologically treated water by the centrifugal force and the cyclone-treated water in which the content rate of the aggregated sludge body is less than the sludge-containing biologically treated water. Generation And the membrane unit is configured to produce the purified treated water by membrane filtration of the supernatant water or the cyclone treated water, and the sludge produced by the gravity settling tank or the cyclone. Sludge concentrated water transfer means for transferring the concentrated water to the biological coagulation tank is provided.

  According to such a membrane separation activated sludge treatment apparatus, the activated sludge contained in the aggregated sludge body in which the activated sludge is concentrated is configured to be aggregated, so that the aggregated sludge body can be generated more efficiently. There are advantages. In addition, there is an advantage that energy for returning the sludge concentrated water can be effectively used.

  Further, in the membrane separation activated sludge treatment apparatus comprising the biological agglomeration tank and the sludge-containing biologically treated water storage tank, preferably, the biological aggregating means agglomerates the activated sludge with a carrier to aggregate the activated sludge from the carrier. The sludge is produced by separating the sludge body, and the carrier comprises an adherend to which the activated sludge is adhered and a support portion for supporting the adherend, and the adherend is swung by a water flow. Consists of.

  According to such a membrane separation activated sludge treatment apparatus, there is an advantage that the aggregated sludge body can be separated from the carrier with energy efficiency by being configured such that the adhering body is swung by the water flow. Further, since the aggregated sludge body can be efficiently generated, there is an advantage that the size of the carrier can be reduced without reducing the generation efficiency of the aggregated sludge body.

  The present invention also provides a mixed water by biologically treating the mixed water by mixing the agglomerated sludge body and waste water generated by the biological aggregating means for biologically aggregating the activated sludge to produce the agglomerated sludge body. A biological treatment process for obtaining sludge-containing biological treated water, and a purified treated water generating process for obtaining purified treated water as permeate from the sludge-containing biological treated water by membrane filtration using a membrane unit, It is in the membrane separation activated sludge treatment method.

  As described above, according to the present invention, it is possible to provide a membrane separation activated sludge treatment apparatus that can markedly improve filtration efficiency, suppress filtration membrane damage and contamination, and have good wastewater treatment efficiency. Further, it is possible to provide a membrane separation activated sludge treatment method that can significantly improve the filtration efficiency, suppress the damage and contamination of the filtration membrane, and have good wastewater treatment efficiency.

1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. AA arrow sectional drawing of FIG. Schematic of the purification process water production | generation part which concerns on one Embodiment. Schematic of the purification process water production | generation part which concerns on one Embodiment. Schematic of the purification process water production | generation part which concerns on one Embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a bioaggregation tank of one embodiment. 1 is a schematic view of a bioaggregation tank of one embodiment. 1 is a schematic view of a bioaggregation tank of one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. 1 is a schematic view of a membrane separation activated sludge treatment apparatus according to one embodiment. The schematic diagram of the purification process water production | generation part used in the Example. The time-dependent change of the differential pressure | voltage between films | membranes when the sludge containing biologically treated water of Example 1 and Comparative Example 1 was membrane-filtered.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the membrane separation activated sludge treatment apparatus according to this embodiment will be described.

  FIG. 1 is a schematic view of a membrane separation activated sludge treatment apparatus of this embodiment. As shown in FIG. 1, the membrane separation activated sludge treatment apparatus 1 according to the present embodiment mixes agglomerated sludge body and wastewater A generated by a biocoagulation means that agglomerates the activated sludge to produce an agglomerated sludge body. A biological treatment unit 2 for producing mixed water and biologically treating the mixed water to obtain sludge-containing biologically treated water, and a membrane unit 31 for performing membrane filtration. And a purified treated water generating unit 3 for obtaining purified treated water B as permeated water.

  Specific examples of the biological treatment include activated sludge treatment. The activated sludge treatment is a treatment in which activated sludge having biological species such as bacteria, protozoa, metazoans and the like and waste water containing organic matter are mixed while aerated to decompose the organic matter with the biological species.

  Further, in the membrane separation activated sludge treatment apparatus 1 of this embodiment, the sludge-containing biological treated water is supplied to the purified treated water generation unit 3 and the purified treated water B as permeated water is supplied to the permeated water storage unit (not shown). Non-permeated water obtained by membrane filtration in the unit 31 is part of the mixed water in the biological treatment unit 2, sludge concentrated water C is part of the sludge concentrated water storage part (not shown) and / or mixed water. It is configured to be transferred to the biological treatment unit 2.

  Further, the membrane separation activated sludge treatment apparatus 1 of the present embodiment, as shown in FIG. 1, is a sludge-containing biologically treated water transfer path 4a for transferring the sludge-containing biologically treated water, and a purification for transferring the purified treated water B as permeate. A treated water transfer path 4b, a sludge concentrated water transfer path 4c for transferring sludge concentrated water C, and a non-permeated water transfer path 4d for transferring non-permeated water are provided.

  The waste water A is not particularly limited as long as it contains organic matter that can be biodegraded. Examples of the waste water A include domestic waste water, food factories, chemical factories, and electronic industry factories. And waste water from factories such as pulp mills.

  As shown in FIG. 2, the biological treatment unit 2 is configured to aerate the sludge-containing biologically treated water storage tank 21, the carrier 22, and the sludge-containing biologically treated water storage tank 21 that stores the generated sludge-containing biologically treated water. And processing aeration means 23.

  The biological aggregating means is produced by aggregating the activated sludge with the carrier 22 and separating the agglomerated sludge body from the carrier 22.

  The carrier 22 is arranged so as to be separated from the membrane unit 31. The carrier 22 includes an attachment 22a to which the activated sludge is attached and a support portion 22b that supports the attachment 22a. Further, the carrier 22 is configured such that the adhering body 22a is swung by a water flow generated by aeration by the biological treatment aeration means 23.

  The adhering body 22a is formed in a thread shape. Although the material which comprises the said adhesion body 22a will not be specifically limited if the said activated sludge adheres easily, As this material, an acrylic resin, polyester, polyethylene, carbon fiber etc. are mentioned, for example. .

  Although the material which comprises the said support part 22b will not be specifically limited if this adherend 22a is supported, As this material, polyester, an acrylic resin, polyethylene, carbon fiber etc. are mentioned, for example. .

The biological treatment unit 2 includes a flocculant addition unit that adds a flocculant to water in which the waste water A and activated sludge are mixed in order to further promote the generation of the aggregated sludge body, as necessary.
As the flocculant, conventionally known flocculants can be used, and examples thereof include inorganic flocculants such as polyaluminum chloride and ferric chloride, and organic polymer flocculants.

  The particle diameter of the aggregated sludge is preferably 1 μm to 10 mm, more preferably 10 μm to 1 mm, and still more preferably 50 μm to 500 μm. In the membrane separation activated sludge treatment apparatus 1 of the present embodiment, since the aggregated sludge body has a particle size of 1 μm or more, the aggregated sludge body easily settles and the solid-liquid separability is improved. There is an advantage that it becomes difficult to occur. Moreover, when the particle diameter of the aggregated sludge body is 10 mm or less, there is an advantage that the clogging between the filtration membranes by the aggregated sludge body can be suppressed.

  As shown in FIG. 1, the purified treated water generation unit 3 is a sludge concentrated water in which agglomerated sludge is concentrated from the sludge-containing biologically treated water D than the sludge-containing biologically treated water by gravity sedimentation of the agglomerated sludge. And a gravity sedimentation tank 32 that produces a supernatant water having a content of the coagulated sludge body smaller than that of the sludge-containing biologically treated water D, and the membrane unit 31 performs membrane filtration of the supernatant water to filter the purified water. Is configured to generate.

  The type of filtration membrane that the membrane unit 31 has is not particularly limited, and examples thereof include a reverse osmosis membrane (RO membrane), an ultrafiltration membrane (UF membrane), and a microfiltration membrane (MF membrane). It is done.

  As the structure of the filtration membrane, a so-called hollow fiber membrane formed into a hollow fiber shape having a diameter of several mm formed of a material such as cellulose acetate, aromatic polyamide, polyvinyl alcohol, polyvinylidene fluoride, polytetrafluoroethylene, and the like Conventionally known types such as a so-called type and a type called a flat membrane which is a thin plate-like film can be employed. Since the flat membrane usually has a membrane clearance of about 10 mm, when the structure of the filtration membrane is a flat membrane, from the viewpoint of suppressing the clogging of the gap by the aggregated sludge body, The particle size is preferably 10 mm or less. Since the hollow fiber membrane has a gap of about 1 mm between the yarns, when the structure of the filtration membrane is a hollow fiber membrane, the aggregated sludge is used from the viewpoint of suppressing the clogging of the gap by the aggregated sludge body. The particle size of the body is preferably 1 mm or less.

  The membrane unit 31 is installed as an immersion membrane below the liquid surface in the gravity settling tank 32.

  The membrane unit 31 includes membrane aeration means (not shown) that removes dirt such as agglomerated sludge adhering to the filtration membrane by aeration of the filtration membrane constantly or intermittently.

  As shown in FIG. 3, the gravity sedimentation tank 32 is provided with an inclined plate 33 on the inner side. The membrane separation activated sludge treatment apparatus 1 according to the present embodiment is provided with an inclined plate 33 on the inside of the gravity sedimentation tank 32, so that the settled aggregate sludge body can be prevented from rising again. Since the amount of the coagulated sludge contained in the clear water can be suppressed, there is an advantage that the filtration membrane is more difficult to clog. In addition, it is easy to reduce the gravity sedimentation tank because it is easy to increase the water area load, or it is easy to lower the separation interface (interface between the supernatant water and sludge concentrated water), so that the installation space for the membrane unit is secured. There is an advantage that becomes easy.

  In addition, the gravity settling tank 32 includes a distributor 34 that distributes and supplies the sludge-containing biologically treated water into the tank, as shown in FIG. 4, if necessary. The membrane-separated activated sludge treatment apparatus 1 according to the present embodiment includes the distributor 34 in the gravity settling tank 32, so that purified treatment water can be supplied to the gravity settling tank relatively evenly. Disturbing the interface between the concentrated water and the supernatant water can be suppressed, and the amount of the aggregate sludge mixed in the supernatant water can be suppressed. Therefore, there is an advantage that the filtration membrane becomes more difficult to clog. In addition, it is easier to downsize the gravity sedimentation tank than the gravity sedimentation tank provided with a center well as means for supplying the sludge-containing biologically treated water into the gravity sedimentation tank, or installation of a membrane unit. There is an advantage that space can be easily secured.

  Furthermore, as shown in FIG. 5, the gravity settling means 32 supplies the swirl supply means D into the tank while swirling the sludge-containing biologically treated water D along the inner peripheral surface of the tank, as shown in FIG. (Not shown). The membrane separation activated sludge treatment apparatus 1 of this embodiment can suppress the flocculation of the sedimented aggregate sludge body by the gravity settling tank 32 including the swivel supply means, and the aggregate contained in the supernatant water. Since the amount of the sludge body can be suppressed, there is an advantage that the filtration membrane becomes more difficult to clog. Further, since the aggregate sludge body can be easily settled by centrifugal force in addition to gravity, the water area load can be increased and the gravity sedimentation tank can be easily downsized, or the sludge is placed in the gravity sedimentation tank. As compared with a gravity sedimentation tank provided with a center well as means for supplying the biological treatment water, there is an advantage that the gravity sedimentation tank can be easily downsized and the installation space for the membrane unit can be easily secured.

  As shown in FIG. 1, the membrane separation activated sludge treatment apparatus 1 of the present embodiment performs non-permeation to oxidize organic substances contained in non-permeated water obtained by membrane filtration in the membrane unit 31 as necessary. A non-permeated water in which an organic substance is oxidized in the non-permeate water treatment unit 5 is transferred to the biological treatment unit 2 as a part of the mixed water.

The non-permeating water treatment unit 5 includes an oxidizing means for oxidizing the organic matter. Examples of the oxidizing means include ultraviolet oxidizing means for irradiating the organic substance with ultraviolet light (UV), ozone oxidizing means for generating ozone (O ₃ ) to ozonolyze the organic substance, and sodium hypochlorite (NaClO). Examples include sodium hypochlorite oxidation means for adding to non-permeated water to decompose the organic matter.

  When the organic matter is oxidized with ozone, the non-permeation water treatment unit 5 exhausts ozone so that ozone is not mixed in the biological treatment unit 2 and the species of the aggregated sludge body is killed (see FIG. Not shown). In addition, when the organic matter is oxidized with sodium hypochlorite, the non-permeation water treatment unit 5 prevents sodium hypochlorite from being mixed into the biological treatment unit 2 so that the biological species of the aggregated sludge body does not die. And a neutralizing section (not shown) for neutralizing sodium hypochlorite with a reducing agent.

  Next, the membrane separation activated sludge treatment method of this embodiment will be described. The membrane-separated activated sludge treatment method of the present embodiment mixes the sludge body and waste water produced by the biocoagulation means that agglomerates the activated sludge to produce the agglomerated sludge body, generates mixed water, and mixes the sludge body. A biological treatment process for biologically treating water to obtain sludge-containing biological treated water, and a purified treated water generating process for obtaining purified treated water as permeate from the sludge-containing biological treated water by membrane filtration using a membrane unit. Become.

  Specifically, the membrane-separated activated sludge treatment method of the present embodiment includes a flocculated sludge body forming step in which waste water A and activated sludge are mixed and the activated sludge is biologically flocculated by the biological flocculating means to generate a flocculated sludge body. The waste water A is further supplied to the biological treatment unit 2, the waste water A and the aggregated sludge body are mixed to produce mixed water, and the mixed water is biologically treated to obtain sludge-containing biological treated water, which contains sludge. By the biological treatment step of transferring the sludge-containing biologically treated water to the gravity sedimentation tank 32 via the biologically treated water transfer path 4a and the gravity sludge of the aggregated sludge body, the aggregated sludge body is formed from the transferred sludge-containing biologically treated water. The sludge concentrated water concentrated from the sludge-containing biological treated water and the supernatant water having a smaller content of the aggregate sludge body than the sludge-containing biological treated water are generated, and the sludge concentrated water is passed through the sludge concentrated water transfer path 4c. C for sludge concentrated water storage tank and Or the gravity separation process which transfers to the biological treatment part 2 as a part of mixed water, this supernatant water is filtered by the membrane unit 3, and the purified treated water and non-permeate water which are permeate are obtained, and the permeate transfer path 4b is set. And a purified treated water generating step of transferring the permeated water to the permeated water storage tank and transferring the non-permeated water as a part of the mixed water to the biological treatment unit 2 via the non-permeated water transfer path 4d.

  Since the membrane separation activated sludge treatment apparatus of this embodiment and the membrane separation activated sludge treatment method of this embodiment are configured as described above, they have the following advantages.

  That is, in the present embodiment, since the aggregated sludge body is aggregated, adhesion to the filtration membrane and clogging of the filtration membrane are difficult to occur. Moreover, damage to a filtration membrane can be suppressed because the aggregate sludge is produced by the biological aggregation means. As a result, the present invention can improve the filtration efficiency, further suppress the damage of the filtration membrane and extend the life of the filtration membrane as compared with the prior art, and suppress the frequency of washing. The effect that the energy cost for this can be suppressed is produced.

  Further, in this embodiment, the biological aggregating means is produced by aggregating the activated sludge with a carrier and separating the agglomerated sludge body from the carrier, so that the carrier itself and the filtration membrane do not come into contact with each other. There is an advantage that damage to the filtration membrane can be further suppressed. Further, since the aggregated sludge body can be generated many times from one carrier, there is an advantage that the activated sludge is easily aggregated as compared with the conventional carrier (fluid carrier).

  Furthermore, in this embodiment, an aeration means for aeration is provided in the biological treatment unit, the carrier is arranged so as to be separated from the membrane unit, and the attached sludge is attached to the attached body. There is an advantage that the coagulated sludge body can be easily generated by being configured so that the attached body swings by aeration by the aeration means.

  In addition, the present embodiment includes the gravity sedimentation tank, and the membrane unit is configured to generate the purified treated water by subjecting the supernatant water to membrane filtration, so that the coagulated sludge body can be easily formed. Since it can be allowed to settle, the supernatant water can be easily formed, and there is an advantage that clogging of the filtration membrane can be further suppressed by filtering the supernatant water with a membrane unit. Therefore, it is possible to reduce the frequency of cleaning the filtration membrane and the amount of aeration for cleaning the membrane.

  Furthermore, in the present embodiment, the membrane unit is installed as an immersion membrane below the liquid surface in the gravity settling tank, thereby simplifying the structure of the device and reducing the size of the device. There are advantages.

  Moreover, this embodiment is provided with the said non-permeation | hydroxylation hydroxylation processing part, and the non-permeation water which the organic substance oxidized in this non-permeation | hydroxylation hydroxylation part is transferred to the said biological treatment part as a part of said mixed water. By being configured in this way, substances that are contained in non-permeate water and are not easily decomposed into agglomerated sludge bodies (hardly decomposable substances) are decomposed into substances that are easily decomposed into agglomerated sludge bodies by oxidation (easily degradable substances). Since the accumulation of the hardly decomposable substance can be suppressed and the fouling can be suppressed, there is an advantage that the filtration membrane becomes more difficult to clog.

  In addition, although the membrane separation activated sludge treatment apparatus of this embodiment and the membrane separation activated sludge treatment method of this embodiment had the above-mentioned advantages by the above configuration, the membrane separation activated sludge treatment apparatus of the present invention. The membrane separation activated sludge treatment method of the present invention is not limited to the above-described configuration, and can be appropriately changed in design.

  For example, in the membrane separation activated sludge treatment apparatus of this embodiment, the adhering body 22a is formed in a thread shape, but in the membrane separation activated sludge treatment apparatus of this embodiment, for example, the adhering body 22a is formed in a spherical shape. Further, the attachment 22a may be configured to swing when the support portion 22b swings due to aeration by the aeration means.

  Further, the membrane separation activated sludge treatment apparatus of the present embodiment is configured such that the membrane unit is installed as a submerged membrane below the liquid surface in the gravity settling tank. 6, a supernatant water storage tank 35 for supplying the supernatant water from the gravity sedimentation tank 32 and storing the supernatant water is provided, and the membrane unit is immersed under the liquid surface in the supernatant water storage tank. May be installed as Even if the aggregate sludge contained in the sludge concentrated water in the gravity sedimentation tank floats in the supernatant water by filtering the supernatant water of the supernatant water storage tank, the suspended aggregate sludge body is osmotic membrane. Therefore, there is an advantage that clogging of the filtration membrane can be further suppressed. In addition, when the filtration membrane is washed with chemicals, it is difficult for the chemicals to be mixed into the sludge-containing biologically treated water storage tank, and there is an advantage that the aggregated sludge body of the sludge-containing biologically treated water storage tank is not easily affected by the chemicals. .

  Furthermore, although the membrane separation activated sludge treatment apparatus of this embodiment is formed in another tank in which the sludge-containing biologically treated water storage tank 21 and the gravity sedimentation tank 32 are separated from each other in FIG. As shown in FIG. 6, in the activated sludge treatment apparatus, the sludge-containing biologically treated water storage tank 21 and the gravity settling tank 32 may be formed by partitioning one tank by the tank partition plate 6. According to such a membrane separation activated sludge treatment apparatus, there are advantages that the structure of the apparatus is simplified and the apparatus can be miniaturized. Moreover, in such a membrane separation activated sludge treatment apparatus, preferably, as shown in FIG. 6, the gravity sedimentation tank 32 has a bottom 32a provided with a sludge concentrated water discharge port, and the bottom 32a has the sludge concentration. It is formed in a tapered shape that tapers downward so as to incline toward the water discharge port. According to such a membrane separation activated sludge treatment apparatus, it becomes easy to draw the sludge concentrated water from the gravity sedimentation tank 32, and it is possible to suppress the aggregation sludge body of the sludge concentrated water from rising, which is contained in the supernatant water. Therefore, there is an advantage that the filtration membrane is more difficult to be clogged.

  Further, the membrane separation activated sludge treatment apparatus of the present embodiment is configured such that the membrane unit 31 generates the purified treated water by subjecting the supernatant water to membrane filtration. As shown in FIG. 7, the sludge treatment apparatus is a type in which a membrane unit 31 is stored in a pressure vessel and is installed outside the gravity settling tank 32, and the supernatant water is added via a pump 7. It may be configured to be supplied to the membrane unit 31 after being pressed. According to such a membrane separation activated sludge treatment apparatus, filtration by high pressure is possible, so that permeated water can be collected with a higher permeation flux compared to the case where the membrane unit is a submerged membrane. There is an advantage that cleaning and the like are facilitated.

  Furthermore, such a membrane separation activated sludge treatment apparatus preferably includes a supernatant hydroxylation treatment unit 8 for oxidizing organic substances contained in the supernatant water, as shown in FIG. The purified water treated by oxidizing the organic matter may be filtered through a membrane, and the purified treated water may be generated. Further, the non-permeated water is oxidized by the non-permeating water oxidation unit 5 and then mixed. You may be comprised so that it may transfer to the sludge containing biologically treated water storage tank 21 as a part of water. According to such a membrane-separated activated sludge treatment apparatus, a substance (persistently degradable substance) that is contained in supernatant water and is not easily decomposed into agglomerated sludge is easily decomposed into agglomerated sludge by oxidation (easily degradable substance). Since it decomposes | disassembles and it can suppress that a hardly decomposable substance accumulate | stores and fouling can be suppressed, there exists an advantage that it becomes difficult to clog a filtration membrane much more.

  In addition, the membrane separation activated sludge treatment apparatus of the present embodiment includes a gravity sedimentation tank that generates sludge concentrated water and supernatant water from the sludge-containing biological treatment water, but the membrane separation activated sludge treatment apparatus of the present invention is As shown in FIG. 8, the purified treated water generating unit includes the sludge concentrated water and the aggregated sludge body in which the aggregated sludge body is concentrated from the sludge-containing biologically treated water than the sludge-containing biologically treated water by centrifugal force. A cyclone 9 that generates cyclone-treated water having a rate lower than that of the sludge-containing biologically treated water, and the membrane unit is configured to produce the purified treated water by subjecting the cyclone-treated water to membrane filtration. In addition, the biologically treated water containing sludge may be transferred to the cyclone 9, and the sludge concentrated water may be transferred to the biological treating unit 2 as part of the sludge concentrated water storage unit (not shown) and / or mixed water. Constitution It may be. According to such a membrane separation activated sludge treatment apparatus, since the content of the coagulated sludge body contained in the cyclone treated water supplied to the membrane unit is reduced, there is an advantage that the filtration membrane becomes more difficult to clog. is there. Further, since the cyclone requires less space than the gravity sedimentation tank, there is an advantage that the filtration membrane can be made less clogged with less space. In addition, the membrane separation activated sludge treatment apparatus of the present invention may include a screen instead of the cyclone 9, specifically, the content rate of the aggregate sludge body from the sludge-containing biological treatment water is the sludge-containing biological treatment. A screen that generates less screen-treated water than water, and the membrane unit may be configured to produce the purified treated water by subjecting the screen-treated water to membrane filtration. It may be configured such that water is transferred to the screen. According to such a membrane separation activated sludge treatment apparatus, since the content of the coagulated sludge contained in the screen treated water supplied to the membrane unit is reduced, there is an advantage that the filtration membrane becomes more difficult to clog. is there. In addition, since the screen requires less space than the gravity sedimentation tank, there is an advantage that the filtration membrane can be hardly clogged with less space.

  Furthermore, in the membrane separation activated sludge treatment apparatus of the present embodiment, the sludge-containing biologically treated water storage tank 21 generates an agglomerated sludge body, but the membrane separation activated sludge treatment apparatus of the present invention, as shown in FIG. The biological treatment section 2 generates a mixed water by mixing the biological flocculation tank 24 for generating the flocculated sludge body by the biological flocculation means and the generated flocculated sludge body and waste water, and biologically treating the mixed water. A sludge-containing biologically treated water storage tank 21 for obtaining sludge-containing biologically treated water, and the purified treated water generating unit 3 is configured to collect the sludge-containing biologically treated water from the sludge-containing biologically treated water by gravity sedimentation. And a gravity sedimentation tank 32 for producing a concentrated sludge concentrated water and a supernatant water having a content of agglomerated sludge bodies that is less than that of the sludge-containing biologically treated water, and the membrane unit 31 contains the supernatant water. Before by membrane filtration Is configured to generate a purified process water becomes, the sludge concentrated water produced by the gravity settling tank 32 may be provided with a sludge concentrate transfer means 10 for transferring the biological flocculation tank 24.

  Further, such a membrane separation activated sludge treatment apparatus includes the agglomerated sludge body transfer path 11 for transferring the agglomerated sludge body generated in the biological agglomeration tank 24 to the sludge-containing biologically treated water storage tank 21. Further, such a membrane separation activated sludge treatment apparatus includes a biocoagulation tank aeration means (not shown) for aeration of the inside of the biocoagulation tank 24 as necessary. (Not shown) may be provided.

  Further, such a membrane separation activated sludge treatment apparatus is formed by dividing the biological aggregating tank 24 and the sludge-containing biologically treated water storage tank 21 into separate tanks.

  Also, in the membrane separation activated sludge treatment apparatus, preferably, the biological aggregating means is produced by agglomerating the activated sludge by the carrier 22 and separating the agglomerated sludge body from the carrier 22. 22 includes an adhering body 22a to which activated sludge is adhered, and a support portion 22b that supports the adhering body 22a, and the sludge concentrated water transferred from the sludge concentrated water transfer means 10 to the biological coagulation tank 24. The adhering body 22a is configured to swing by the water flow. Further, in such a membrane separation activated sludge treatment apparatus, the sludge concentrated water can be transferred in a turbulent flow as the biocoagulation tank 24 instead of the biocoagulation tank 24 configured to aggregate the activated sludge with the carrier 22. Thus, the length of the transfer path is extended, the path is subdivided, specifically, the flow path as shown in FIG. 10 is zigzag, or the multi-tubular shape as shown in FIG. A (honeycomb-shaped) thing or a thing provided with a static mixer as shown in FIG. 12 may be provided. According to such a membrane separation activated sludge treatment apparatus, activated sludge can collide with a wall-like thing at high speed, and there exists an advantage that a coagulated sludge body can be produced | generated efficiently.

  Further, as shown in FIG. 13, such a membrane separation activated sludge treatment apparatus has a flocculated sludge body from the sludge-containing biologically treated water by centrifugal force instead of the gravity sedimentation tank 32 than the sludge-containing biologically treated water. A cyclone 9 for generating concentrated sludge concentrated water and cyclone-treated water in which the content of the coagulated sludge body is less than that of the sludge-containing biologically treated water, and the membrane unit 31 membrane-filters the cyclone-treated water The sludge concentrated water transfer means 10 is configured to transfer the sludge concentrated water generated by the cyclone 9 to the biological coagulation tank 24.

  Moreover, as shown in FIG. 14, the membrane separation activated sludge treatment apparatus of the present invention has a biological flocculation tank 24 in which the biological treatment unit 2 generates a flocculated sludge body by the biological flocculation means, and the generated flocculated sludge. And a sludge-containing biologically treated water storage tank 21 for producing a mixed water by mixing the body and waste water and biologically treating the mixed water to obtain a sludge-containing biologically treated water. The permeated water is configured such that the coagulated sludge body is more concentrated than the sludge-containing biologically treated water in the sludge-containing biologically treated water storage tank 21, and the non-permeated water is transferred to the biological aggregating tank. Non-permeate water transfer means 12 may be provided. Moreover, in such a membrane separation activated sludge treatment apparatus, the sludge-containing biological treated water is transferred to the membrane unit 31 via the pump 13, and the non-permeate water E is stored in a non-permeate water storage tank (not shown) as required. It is comprised so that it may be transferred to.

  Further, in such a membrane separation activated sludge treatment apparatus, preferably, the biological aggregating means is produced by aggregating the activated sludge with a carrier 22 and separating the agglomerated sludge body from the carrier 22, and the carrier. 22 includes an adhering body 22a to which activated sludge is adhered, and a support portion 22b that supports the adhering body 22a, and the non-permeated water transferred from the non-permeated water transfer means 12 to the biological coagulation tank 24. The adhering body 22a is configured to swing by the water flow.

  Moreover, as shown in FIGS. 15 to 17, the membrane separation activated sludge treatment apparatus of the present invention is configured so that the carrier 22 is accommodated under the water surface of the sludge-containing biologically treated water storage tank 21 and the biological coagulation tank 24, respectively. It may be configured.

  Next, the present invention will be described more specifically with reference to examples and comparative examples.

Example 1
Sludge-containing biologically treated water storage tank (volume: 10.6 L, internal dimensions: 115 cm (width) x 145 cm (depth) x 640 cm (height)), Biofringe (registered trademark) as a carrier (NTT Corporation) And sludge containing biologically treated water of Example 1 was produced by mixing activated sludge and wastewater using a pump as a biological treatment aeration means to produce agglomerated sludge body. Specifically, first, wastewater (1000 mg / L of BOD mainly composed of fish extract and peptone is contained in the sludge-containing biologically treated water storage tank and adjusted to pH 7.0 with NaHCO ₃ as a pH buffer component. Waste water) and activated sludge were added (this time is hereinafter referred to as “initial injection”). And it aerated by the biological treatment aeration means for one day, the waste water and activated sludge were mixed, and the activated sludge was aggregated with the support | carrier. Thereafter, 2.5 L / d for one week from the initial injection (except for one day from the initial injection), 5 L / d for 1-2 weeks, 10 L / d for 2-3 weeks, Inject wastewater at a constant rate of 15 L / d for 3 to 5 weeks, 23 L / d for 5 to 7 weeks, 30 L / d for 7 to 8 weeks, and discharge wastewater and activated sludge. Aerated while mixing, the activated sludge was agglomerated by the carrier and separated from the carrier to produce an agglomerated sludge body, and the sludge-containing biologically treated water of Example 1 was produced. Aeration was performed at an air amount of 10 L / min. Moreover, the sludge in the said sludge containing biological treatment water storage tank was extracted so that MLSS in the said sludge containing biological treatment water storage tank might be 9,000-10,000 mg / L.

(Example 2)
The same method as Example 1 except having extracted the sludge in the said sludge containing biological treatment water storage tank so that MLSS in the said sludge containing biological treatment water storage tank may be 5,000-6,000 mg / L. Thus, as shown in Table 1, the sludge-containing biologically treated water of Example 2 having an MLSS of 5,660 mg / L and an MLVSS of 5,270 mg / L was generated.

(Comparative Example 1)
A comparative example in which the MLSS and MLVSS of the purified water of Example 1 are comparable as shown in Table 1 in the same manner as in Example 1 except that Biofringe (registered trademark) as a carrier was not installed. 1 sludge-containing biologically treated water was produced.

(Comparative Example 2)
A comparative example in which the MLSS and MLVSS of the purified treated water of Example 2 are comparable as shown in Table 1 in the same manner as in Example 2 except that Biofringe (registered trademark) as a carrier was not installed. Two sludge-containing biologically treated water was produced.

  The sludge-containing biologically treated water of Examples and Comparative Examples was subjected to the following test.

  MLSS, MLVSS, and activated sludge sedimentation rate (SV30) in the sludge-containing biologically treated water of Examples and Comparative Examples were measured according to JIS B 9944 (“Test Method for Activated Sludge Treatment Apparatus”). Further, the ratio of MLVSS to MLSS (VSS / SS ratio) was calculated.

  5 types C (JIS P 3801) filter paper (manufactured by Advantech, diameter 18.5 cm) is placed on the filter, and 50 mL of the sludge-containing biologically treated water of Examples and Comparative Examples is dropped on the filter paper. After 5 minutes, the amount of filtrate (permeated water) that permeated the filter paper (permeated water amount) was measured.

  The viscosity in the sludge-containing biologically treated water of Examples and Comparative Examples was measured with a viscometer (trade name: Viscotester VT-03F, manufactured by Rion Corporation).

  The sludge-containing biologically treated water of Examples and Comparative Examples was filtered with the 5 C filter paper to obtain a filtrate (permeated water). The total organic carbon (TOC) concentration (TOC (5C) in the permeated water) contained in the permeated water was measured with a TOC meter (trade name: TOC-5000A, manufactured by Shimadzu Corporation).

  The sludge-containing biologically treated water of Examples and Comparative Examples was filtered with 0.1 μm filter paper (manufactured by Advantech) to obtain a filtrate. The total organic carbon (TOC) concentration (TOC in the permeated water (0.1 μm)) contained in the filtrate was measured with the TOC meter.

The concentration of soluble microorganism products (SMP) in the sludge-containing biologically treated water of Examples and Comparative Examples was calculated by the following formula (1).
SMP = TOC (5C) -TOC (0.1 μm) (1)

As shown in FIG. 18, each of the sludge-containing biologically treated water of Example 1 and Comparative Example 1 was put into a 500 L tank 51, and an immersion membrane 52 (made of polyvinylidene fluoride (PVDF), pore size: 0) as a membrane unit. 1 μm, surface area: 0.05 m ³ ) is immersed in the sludge-containing biologically treated water 53 in the tank 51, and the membrane is filtered while constantly stirring the sludge-containing biologically treated water 53 with the stirrer 54 and aeration with the blower 55. The differential water pressure (transmembrane differential pressure) was measured with a pressure data logger 56 (trade name: DAQSTATION DX120, manufactured by Yokogawa Electric Corporation). FIG. 19 shows the change over time in the differential water pressure. The measurement was performed under conditions of a temperature of 25 ° C. and a permeated water flux of 0.6 m / d. In addition, in the sludge-containing biologically treated water of Comparative Example 1, it became impossible to recover the permeated water under the condition of a flux of 0.6 m / d due to clogging of the membrane immediately after the start of measurement. FIG. 10 shows a value converted as a differential water pressure at a permeated water flux of 0.6 m / d. The converted value was calculated by the following formula (2).
Membrane pressure difference (converted value)
= Membrane differential water pressure (actual measured value) x 0.6 m / d ÷ permeation flux (m / d) (actual measured value) (2)

  The results of the above test are shown in Table 1 and FIG.

  The sludge-containing biologically treated water of Examples 1 and 2 within the scope of the present invention has the same MLSS and MLVSS, and the sludge-containing organism of Comparative Examples 1 and 2 having activated sludge that has not been aggregated. SV30, viscosity, SMP, permeated water TOC (5C), permeated water TOC (0.1 μm) showed lower values than treated water. Moreover, as shown in FIG. 10, in the membrane filtration of the sludge containing biologically treated water of Example 1 which is within the scope of the present invention, compared to the membrane filtration of the sludge containing biologically treated water of Comparative Example 1, it is between the membranes. The differential pressure was small and stable, indicating that contamination of the filtration membrane was suppressed.

  1: membrane separation activated sludge treatment device, 2: biological treatment unit, 3: purified water generation unit, 4a: biological treatment water transfer route containing sludge, 4b: purified treatment water transfer route, 4c: sludge concentrated water transfer route, 4d : Non-permeate water transfer path, 5: non-permeate water treatment unit, 6: tank partition plate, 7: pump, 8: supernatant water treatment unit, 9: cyclone, 10: sludge concentrated water transfer means, 11: coagulated sludge Body transfer path, 12: Non-permeate water transfer means, 13: Pump, 21: Sludge-containing biologically treated water storage tank, 22: Carrier, 22a: Adherent, 22b: Support part, 23: Biological treatment aeration means, 24: Biological Coagulation tank, 31: membrane unit, 32: gravity sedimentation tank, 33: inclined plate, 34: distributor, 35: supernatant water reservoir, 51: tank, 52: immersion membrane, 53: biological treatment water containing sludge, 54: Stirrer, 55: Blower, 56: Pressure de Logger, A: wastewater, B: purified treated water, C: sludge concentrated water, D: sludge containing biologically treated water, E: Non-permeate

Claims (3)

  The agglomerated sludge body produced by the biological aggregating means that biologically agglomerates the activated sludge and the waste water are mixed to produce mixed water, and the mixed water is biologically treated to produce sludge-containing biologically treated water. A membrane separation activated sludge treatment apparatus comprising a biological treatment section to be obtained and a purified treatment water generation section having a membrane unit for performing membrane filtration and obtaining purified treatment water as permeated water by membrane filtration from the sludge-containing biological treatment water And the biological treatment unit mixes the produced flocculent sludge body and waste water with the biological flocculant tank that produces the flocculent sludge body by the biological flocculant means to produce mixed water, and biologically treats the mixed water. Sludge-containing biologically treated water storage tank for obtaining sludge-containing biologically treated water, and the non-permeated water generated by the membrane unit is more coherent than the sludge-containing biologically treated water in the sludge-containing biologically treated water storage tank. With concentrated body It is configured so that, the non-permeate non permeate transfer means for transferring the biological flocculation tank, characterized in that is provided with membrane separation activated sludge treatment apparatus.   The agglomerated sludge body produced by the biological aggregating means that biologically agglomerates the activated sludge and the waste water are mixed to produce mixed water, and the mixed water is biologically treated to produce sludge-containing biologically treated water. A membrane separation activated sludge treatment apparatus comprising a biological treatment section to be obtained and a purified treatment water generation section having a membrane unit for performing membrane filtration and obtaining purified treatment water as permeated water by membrane filtration from the sludge-containing biological treatment water And the biological treatment unit mixes the produced flocculent sludge body and waste water with the biological flocculant tank that produces the flocculent sludge body by the biological flocculant means to produce mixed water, and biologically treats the mixed water. A sludge-containing biologically treated water storage tank that obtains sludge-containing biologically treated water, and the purified treated water generating unit concentrates the aggregated sludge body from the sludge-containing biologically treated water more than the sludge-containing biologically treated water by gravity sedimentation. Sludge concentrated water and Gravity sedimentation tank that produces a supernatant with less sludge body content than the sludge-containing biologically treated water, or agglomerated sludge body from the sludge-containing biologically treated water by centrifugal force than the sludge-containing biologically treated water A cyclone that generates concentrated sludge concentrated water and a cyclone-treated water having a content of agglomerated sludge body that is less than the sludge-containing biologically treated water is provided, and the membrane unit membrane-filters the supernatant water or the cyclone-treated water It is configured to generate the purified treated water, and is provided with sludge concentrated water transfer means for transferring the sludge concentrated water generated by the gravity sedimentation tank or the cyclone to the biological coagulation tank. Membrane separation activated sludge treatment equipment.   The biological aggregating means is formed by aggregating the activated sludge with a carrier and separating the agglomerated sludge body from the carrier, and the carrier supports the adherent to which the activated sludge is adhered and the adherent. The membrane-separated activated sludge treatment apparatus according to claim 1, further comprising a support portion, and configured so that the adhering body is swung by a water flow.

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