JPH0212638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a pollution-related prevention technology. The present invention has remarkable effects on biological treatment of wastewater, especially treatment by catalytic oxidation method. Applicable wastewater includes sugar wastewater, fishery processing wastewater, and residential domestic wastewater. The term "catalytic oxidation method" used in the present invention is a method that can be said to be one of the improved activated sludge methods, and is a method in which a contact material such as edagashi, which grows and acclimatizes microorganisms, is placed in an aeration tank and aerated. be. The term "contact material" used in the present invention refers to a carrier for microorganisms to form colonies, proliferate, and acclimatize in the biological treatment of drinking water, industrial water, sewage, sludge, etc. It is a synonym for "living organism" or "microbial symbiotic carrier." Other terms used in the present invention will be explained or defined one by one. Conventional Technology Activated sludge method is currently widely used as a biological treatment method for wastewater. The activated sludge process usually consists of four stages: an initial settling tank, an aeration tank, a final settling tank, and return of the activated sludge to the aeration tank. The activated sludge method is generally suitable for treating wastewater with a high amount of organic matter, but in order to operate this method successfully, it is necessary to ensure that the microorganisms necessary for purification are appropriately present in the activated sludge and are sufficiently active. be. Furthermore, the activated sludge method requires long aeration times and large amounts of air, and aeration operations account for a large portion of operation and management costs. Therefore, various improvement methods have been developed taking into consideration operational stability, treatment efficiency, difficulty in maintenance and management, economic efficiency, etc. The contact oxidation method, which is an improved method of the activated sludge method, is a method in which a contact material for immobilizing microorganisms is placed in an aeration tank and aeration is performed. The effects of the contact oxidation method are that the amount of microorganisms in the aeration tank increases, which improves treatment efficiency, and that a food chain is established with a wide variety of microorganisms that grow and become accustomed to the contact material, reducing the amount of surplus sludge. It is what happens. On the other hand, there is a drawback that microorganisms grow excessively on the contact material, which impairs the fluidity of the mixed liquid and impedes oxygen transfer. Therefore, an important issue in the catalytic oxidation method is what material, shape, and physical properties should be selected for the contact material. Conventionally, the concept of the contact material used in the contact oxidation method is to seek growth and acclimatization of microorganisms on a plate-shaped surface.
Based on the idea that the more surfaces there are, the more microorganisms can be attached and retained, honeycomb-shaped, rod-shaped, linear, and other deformed plastics have been adopted. This type of planar contact material has the disadvantage that microorganisms grow and become accustomed to the contact material in a relatively thick layer, and if the thickness exceeds a certain amount, it may cause clogging or peel off. Therefore, cumbersome additional management operations are required, such as limiting the load of the EOD amount on the processing equipment or providing a cleaning mechanism for the contact material. Furthermore, in the conventional aeration method, a method is adopted in which a cylindrical, plate-shaped, dome-shaped, etc. aeration pipe is used, and air is introduced by a blower and discharged into the water. Methods for installing aeration tubes include the full-surface aeration method from below the filled contact material, the linear concentrated aeration method in areas where the contact material is not filled, and the method using diffuser pipes arranged perpendicular to the water flow below the contact material. Various methods have been used, including mixing and contacting waste water with air using internal swirling flow or vertical flow. The tangential concentrated aeration in the unfilled part of the contact material is surprisingly small in the center of the filled contact material, and the flow velocity in the unfilled part becomes faster, and the amount of biofouling near the upward flow becomes smaller.
Moreover, most of the bubbles are released into the atmosphere. In addition, although full surface aeration and linear aeration methods perpendicular to the water flow both allow water flow to occur at the center of the contact material, they tend to cause detachment of the attached biofilm, and the ecology of the attached organisms on the surface layer may be affected. Furthermore, when a blockage occurs, it is necessary to remove the contact material to replace the diffuser pipe, and the attached organisms fall off at this time, resulting in a decrease in the subsequent treatment effect. . Problems to be Solved by the Invention The present invention provides a method for catalytic oxidation of wastewater that exhibits high treatment efficiency without causing the microorganisms that have grown and become accustomed to the contact material to peel off or fall off. According to the present invention, there is provided an aeration tank that is equipped with a contact material that does not allow the microorganisms that have grown and become accustomed to it to peel off and fall off, and that has a higher oxygen absorption rate with a smaller amount of aeration than before. The present invention provides a method and apparatus for catalytic oxidation of wastewater, which creates a concentration gradient in the biota in each tank by arranging aeration tanks in multiple stages, thereby significantly increasing the treatment target value and the efficiency of phosphorus removal. The present invention provides a method and apparatus for catalytic oxidation of wastewater that generates a very small amount of sludge and does not require removal of excess sludge. The problems solved by the present invention will be successively clarified below. Means for Solving the Problems The above-mentioned problems arise when a plurality of untwisted bundles of wires arranged diagonally across a suitable core wire are used in the multi-stage catalytic oxidation process in wastewater treatment. Consists of yarn and untwisted filament,
The filaments are pulled out from between the wound portions of the bundled yarn, and each filament is moved outward in the radial direction of the core wire 11
An aeration tank consisting of contact materials arranged in unbound independent radial loops of ~14 mm is used, and a mixture of circulating water and air is fed into the aeration tank under high pressure. This is solved by supplying The filament is preferably polyvinylidene chloride. The contact material used in the present invention is charged by changes in the microscopic ion concentration in the water, and the microorganisms generated in the water are efficiently attached to the loop, multiplying and becoming accustomed to it, and repeating exponential growth under oxygen and other conditions. The entire contact material becomes rod-shaped.
The maximum diameter at this time is about 20 to 35 m/m, and it will not enlarge beyond that state. In the process of reaching this state, the oxygen supplied in the water is gradually consumed from the surface layer of the deposit, and decreases toward the center of the deposit, resulting in a facultative anaerobic state. This is because microbial activities in the accumulated sludge cause microscopic changes, such as decomposition of biological remains and metabolites, consumption of _O2 , release of gaseous substances such as carbon dioxide and methane gas, and changes in various inorganic substances caused by microorganisms. In either case, the conditions of the microscopic environment change significantly. In the above state, protozoa swim in the gaps between the microorganisms and blue-green algae entangled in the radial loop, and bacteria and chlorella float. Furthermore, a large number of bacteria and chlorella adhere firmly to the surface of blue-green algae. The following results have been reported regarding the biological significance of these microbial communities. The following experimental results have been reported by comparing the biota between two biota that were cultured under exactly the same conditions, that is, one that was allowed to form a colony and the other that was not. That is, if water in which microorganisms have been cultured is stirred for just a few tens of seconds a day, it becomes a stable phase that does not form colonies, whereas if it is left to stand still, it forms colonies. When we examine both types of organisms, we find that in the former, no worms appear at all, and the population of microorganisms such as rotifers and protozoa has significantly decreased by about 1/10. This experiment experimentally demonstrated that disruption of the system structure suppresses species diversification and population growth. ...That's what it says. Therefore, system structure is essential for the coexistence and stability of more species. The reason why species diversify and increase in number when they form a settlement is probably because the diversification of the environmental structure provides suitable habitats for more species.
It can be inferred that this is because the exchange and transmission of energy substances between biota is carried out efficiently. When a colony is formed, the groups of organisms are located close to each other, allowing the mammals to feed efficiently and the prey organisms to hide within the colony and avoid being eaten. Therefore, bacteria, chlorella, and protozoa are not eaten up by earthworms and rotifers. Next, it is thought that there are areas inside the village where metabolites are adsorbed and concentrated, and this is a favorable environment for organisms such as bacteria, chlorella, and blue-green algae that multiply by exchanging metabolites. In the surrounding area, the concentration of metabolites is thought to be diluted by diffusion into the liquid area, and this allows organisms that are sensitive to metabolites, such as rotifers, protozoa, and earthworms, to coexist in the village. These local differences in the concentration of metabolites allow various organisms to coexist in a village, shorten the distance between them, and create an environment for efficient reproduction and reuse. It contains the producers, consumers, and decomposers necessary for energy exchange, transfer, and material circulation, and satisfies almost self-sufficient forms. It should be noted that the fact that a large number of villages exist at almost equal intervals and that they are surrounded by a liquid layer and an upper layer is thought to compensate for defects or imbalances that occur within a particular village, and this structural differentiation is thought to play a role in protecting the system from external disturbances. As has been demonstrated by citing several theories, the ingenious structure of the present invention achieves a delicate balance among various organisms and repeats stable colony activities due to the successive supply of nutrients. A generational change takes place in the contact material, and the sludge attached to the ring does not become obese indefinitely, and its shape maintains a diameter of about 20 to 35 m/m, contributing to the achievement of the initial purpose. Of course, in order to stabilize this state, it must be recognized that the most important requirement is how to adjust the amount of dissolved oxygen in each tank. Aeration is not based on the simple idea of measuring the contact effect by increasing the amount of oxygen, but rather the supply of oxygen amount appropriate for each biota.
m/m, and the attached sludge diameter is about 35 m/m, which is a condition that should be met by optimizing the distribution of oxygen to the central portion.If this condition is satisfied, the attached sludge will not expand indefinitely. The unique shape and structure of the contact material of the present invention, the microorganisms that grow and become accustomed to it, and the food chain in water have been described in detail above, and the structure of the present invention will be explained below. The present invention comprises a plurality of untwisted bundled yarns arranged diagonally across the periphery of a soft plastic pipe through which a core wire is inserted, and an untwisted polyvinylidene chloride filament, and the filaments are wound with the bundled yarns. A contact material is used in the aeration oxidation tank, and is made of a contact material that is pulled out from between the rotation parts and forms an independent radial loop of 11 to 14 mm in an unbound state radially outward of the core wire with each filament. It is characterized by supplying a mixture of circulating water and air under high pressure into the aeration tank. In the present invention, the untwisted convergent yarn and the untwisted filament are not directly wound around the core wire material, but the core wire material is inserted through a soft plastic pipe, and the untwisted convergent yarn and the untwisted filament are wound around the plastic pipe. ing. Thereby, corrosion due to oxidation of the core wire and generation of static electricity can be prevented. Hereinafter, the shape and structure of the contact material of the present invention, modes of use, etc. will be explained based on the drawings. 1-a, b and 2-a, b are a side view and a radial cross-sectional view, respectively, of a contact material used in the present invention. The contact material used in the present invention is a soft plastic pipe 1 through which an aluminum alloy concentric wire with a diameter of about 2 mm is inserted, and a radial loop 2 is formed in the radial direction.The length a from the tip of the loop to the tip is 20~ The range is 35mm. The length of the core wire 1 is arbitrarily selected depending on the size of the aeration oxidation tank used. When the contact material of the present invention is used in an aeration oxidation tank, it is formed into various shapes such as a rod shape, a spiral shape, etc., but the void volume, in other words, the magnitude of the effect of a unit volume of wastewater coming into contact with the contact material When considering this, forming the material into a spiral shape acts as a resistance to the flow within the tank, creating a gentle swirling flow near the contact material and enhancing the contact effect. FIGS. 1 and 2 are a side view and a radial cross-sectional view, respectively, of a helically formed contact member. In Figure 2 1, b is the helical pitch measured between the loop and the tip of the loop, which is 35 mm or more.
In Fig. 2, c is the inner diameter measured at the tip of the loop, which is 35 mm or more. That is, it consists of a plurality of untwisted bundled yarns arranged so as to intersect with each other in the diagonal direction around the core wire of the present invention and an untwisted polyvinylidene chloride filament, and the filaments are inserted between the wound portions of the bundled yarns. The diameter at the tip of the loop is made by drawing out each filament and forming an independent radiating loop of 11 to 14 mm in the radial direction of the core wire.
Contact material of 20 to 35 mm is formed into a spiral shape with a pitch of 35 mm or more at the loop tip and an inner diameter of 35 mm or more at the loop tip (hereinafter, the spirally formed contact material is referred to as a "contact material unit"). (There may be cases.)
By arranging the helical contact material in such a structure, blockage due to excessive microbial attachment, which is one of the drawbacks of conventional contact materials, is prevented. The present invention uses a plurality of the above-described spiral contact material units held by a frame made of a suitable corrosion-resistant material. Figures 1 and 2 show front and side views, respectively, of a contact unit 15 held in a frame 16 made of a suitable corrosion-resistant material. d is the distance between the loop tips of each contact material unit and is set to 35 mm or more. In the present invention, a structure in which a plurality of such contact material units are held in a frame is referred to as a "contact material module." The contact material module used in the present invention can be arbitrarily designed depending on various conditions such as the volume of the aeration tank to be inserted and the water depth. For example, in the case of large equipment, it is possible to manufacture small blocks and assemble them on site. FIG. 4 is a partial sectional view showing a state in which four contact material modules are inserted into the aeration tank 5 . 6 indicates a waste water inlet and 7 indicates a treated water outlet. INDUSTRIAL APPLICATION This invention is utilized for the treatment method of wastewater by a catalytic oxidation method. Although it is possible to achieve the desired purpose with a single aeration tank for contact oxidation, the contact oxidation method is originally a continuous process, and raw water is continuously supplied, so it may be difficult to Judging from this, even if the aeration tank has the same volume, it will be more effective to divide it into multiple stages. In other words, by dividing the aeration tank into several stages, a microbial colony suitable for the water quality in each aeration tank can work effectively, and it is possible to reduce the concentration of raw water to about 2 to 5 ppm if necessary, regardless of the raw water concentration. . In order to divide the aeration tanks in this way and create concentration gradients in each tank, it is necessary to completely separate each type of tank, and the design and arrangement are such that they are blocked except for the communicating parts. The structure and effects of the present invention will be discussed in comparison with the conventional method with reference to FIGS. 5, 6 and 7. FIG. 5 1 is a flow sheet of an example of an apparatus used in the conventional activated sludge method. FIG. 5 is a flow sheet of an example of an apparatus for carrying out the conventional air diffuser method disclosed by the present inventor in an earlier application (Japanese Patent Application No. 107955/1982). FIG. 52 shows an embodiment in which the secondary treatment aeration tank has four stages and the tertiary treatment aeration tank has three stages. In Figure 5, 6 is a wastewater supply line, 7 is a treated water discharge line, 8 is an adjustment tank, 9a is a conventional aeration tank, 9b is a secondary treatment tank, 9c is a tertiary treatment tank, 10 is a contact material module, 11 is a compressor, 12 is a sedimentation tank, 13 is a dehydrator, and 14 is an incinerator. In the conventional activated sludge method, pre-treated wastewater is passed from the wastewater supply line 6 to the adjustment tank 8.
The sludge and treated water mixture in the aeration tank is then introduced into the aeration tank 9a , where it comes into contact with microorganisms that have been grown and acclimatized in the target wastewater and is aerated and mixed for a certain period of time, and then the mixture of sludge and treated water in the aeration tank is allowed to flow naturally. The sludge is then gently introduced into the sedimentation tank 12 , where an appropriate surface load is applied to the mixed liquid and the sludge is sedimented and separated.
The supernatant liquid (treated water) is normally discharged through the discharge line 7 , while the sludge settled at the bottom of the settling tank is continuously returned to the aeration tank through the line 17 and mixed with newly inflowing wastewater. On the other hand, excess sludge is dehydrated by a dehydrator 13 , incinerated in an incinerator 14 , and disposed of. On the other hand, in the present invention, pretreated wastewater is introduced from the wastewater supply line 6 into the adjustment tank 8 and then into the secondary treatment aeration tank 9b . The aeration tank 9b is divided into four tanks, and a contact material module having the above-described shape and structure is inserted into each tank. The volume of each tank may be the same, or the volume may be changed depending on the conditions. The wastewater introduced into the aeration tank 9b is first brought into contact with the microorganisms that have adhered to the contact material and grown and acclimatized in the first tank, and is aerated and mixed for a certain period of time.
After 40 to 60% of BOD and COD components have been removed from the raw water, the supernatant (treated water) is transferred to the second, third, and fourth tanks, and finally the supernatant (treated water) from which pollutants have been removed is sent to the line. It is released from 7 . On the other hand, depending on the type of wastewater, a part of the supernatant liquid is introduced into the tertiary treatment tank 9c , and the supernatant liquid (treated water) is dechambered and dephosphorized by the same mechanism as in the secondary treatment tank 9b . is discharged from line 7. The aeration method according to the present invention does not use the conventional activated sludge method or aeration pipe method, but instead uses the contact material specified by the present invention to supply a mixture of circulating water and air to the aeration tank under high pressure. This is a catalytic oxidation method. Figures 6 and 7 both show the conventional diffuser tube aeration system used in the catalytic oxidation method (biofilm method). Most of them are dome-shaped, etc., and the structure of the diffuser tube is made by bonding and sintering fine particles of inorganic or synthetic resin, and diffuses air by injecting air from the pores between the particles. These are aimed at ultra-fine pores to increase air dissolution efficiency, but as the pore size becomes smaller, ventilation resistance increases, and conditions such as the viscosity, density, surface tension, and injection pressure of the wastewater and air come into play, making the pores smaller than the current one. There is a problem in obtaining air bubbles, and in addition, as the pore size becomes smaller, the phenomenon of clogging occurs more frequently. Under such circumstances, in the case of linear concentrated aeration in areas where contact material is not filled, the downward flow rate in the contact material area is unexpectedly slow compared to the upward flow rate, which tends to lead to an oxygen-deficient state. As a result, the sludge adhering to the contact material is washed away. In addition, full-surface aeration has the disadvantage that the contact material becomes resistant, which tends to cause bubbles to become coarser, and to frequently cause peeling. (A considerable flow rate is required to make the bubbles finer by repeating the collisions of the rising bubbles.) To solve this problem, the present invention utilizes the phenomenon of bubble precipitation caused by pressurized water. Pressurized water is made by blowing water and air into a closed tank under a pressure of about 5 kg/cm ² .
A supersaturated state is achieved by allowing the water to flow for about 5 minutes and circulating it using a pump or the like. When this is released into water under normal pressure, bubbles are precipitated and colloidal bubbles can be obtained. Utilizing this phenomenon, it is possible to continuously supply sufficient oxygen and a gradual upward flow, and it is possible to completely prevent peeling when performing full-surface aeration. In this case, the size of the pressurized water outlet is incomparable to the diameter of the air diffuser tube hole, so there is no need to consider blockage. This will be explained below using figures. FIG. 81 is a schematic diagram of a longitudinal section of an aeration tank and a pressurized water device, 31 is an aeration tank, 32 is a contact material module, and treated water 33 purified in the aeration tank is discharged, but some of it is Pump P ₁ presses 34 ejectors into 5. The inside of the tank of No.35 should be about 5Kg/ ^cm2 . Air is automatically sucked in from 37 using the negative pressure generated when water passes through the pump 44, or blown in by a compressor 36.
The water stored in the tank 35, including the air sucked in from 32, is circulated by the pump 45.
At this time, the oxygen is circulated for the required residence time to ensure a uniform distribution of oxygen, passes through 39 pressure reducing valves, and passes through 40 conduits.
It is guided into the aeration tank and discharged into the water from a discharge pipe 41. When the pressure is returned to atmospheric pressure, the saturated oxygen is precipitated from the pressurized water, forming microbubbles and rising. The internal pressure of tank 35 is checked with a pressure gauge 43, and excess air is exhausted through a degassing valve 38.
2 is a partial plan view of the aeration tank. The broken line indicates the contact material filling part, and 41 indicates an example of how the pressurized water discharge pipe is installed. Figure 9 is a plan view of the aeration tank, where the treated water 33 is sucked in by a pump and sent to the evacuation tank 34 on the discharge side.
and the discharge pipe 41 of each aeration tank via 40 pipes.
It makes it squirt more. Figure 9 2 shows the outline of the ejector, and the water pumped by the pump is
By making the tip of 1 thinner, the flow rate is increased and discharged. When water passes through the center of 52, the cavity 53 becomes under negative pressure and sucks air from 54. When the sucked air passes through the container 52, it comes into contact with the circulating water, dissolves under high pressure, and is discharged. By spraying this water into water, fine bubbles are generated. Depending on the size of the aeration tank, an appropriate number can be used, or they can be installed in opposing directions within the aeration tank. In the aeration method using an aeration tube, the air released from the orifice rises through the liquid, reaches the water surface, ruptures, and dissipates into the atmosphere. While these bubbles rise in the liquid, molecular diffusion takes place through the gas film and liquid film, and turbulent diffusion accompanying the upward flow and turbulent flow at the water surface cause the saturated bubble film to move into the liquid surface layer. Oxygen is supplied by rolling it into the tank. The size of the bubbles leaving the diffuser tube is related to the diameter of the orifice and the airflow rate. That is, the volume of a bubble is determined by the diameter of the orifice and the surface tension of the liquid, and this relationship is directly proportional and inversely proportional to the density of the liquid, and the bubbles that come out of the orifice leave the diffuser tube and rise due to the shear force. At this time, when the amount of air increases or when the rigid surface buffers, a coarsening phenomenon occurs in which air bubbles are combined. While the bubbles supplied in this manner rise through the liquid, oxygen is absorbed and the oxygen concentration in the gas phase is reduced. When the bubble diameter at this time is small, the gas-liquid contact membrane becomes large and the supplied oxygen is efficiently utilized. The air bubbles supplied according to the present invention are produced by mixing air into a liquid that has been pressurized above atmospheric pressure in advance to increase dissolution efficiency as fine bubbles and releasing them into the liquid at atmospheric pressure. As a result, dissolved oxygen precipitates due to the pressure difference and forms fine bubbles. The bubble diameter at this time is 30~
It becomes extremely fine, said to be 120μ. Therefore, the wastewater to be treated is pressurized, air is mixed in it, and the wastewater is allowed to stagnate for 3 to 5 minutes before being supplied to each aeration tank. At this time, it becomes saturated under high pressure, and preliminary oxidation proceeds by providing backflow circulation, and by dispensing it to the aeration tank, more effective organic matter treatment becomes possible. The structural differences between the conventional activated sludge and aeration tube systems and the catalytic oxidation method of the present invention have been compared and discussed above. This eliminates the need for the operation of continuously returning sludge to the aeration tank (return sludge), reduces the amount of surplus sludge generated, eliminates the need for cleaning work due to blockages, and reduces the amount of aeration. In addition to the essential advantages, there are other equipment and structural advantages such as the treatment tank being made smaller and various equipment such as a settling tank, dehydration tank, and incinerator becoming unnecessary. Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1, Comparative Example 1 Using the conventional device shown in FIG. 5 2 and the device of the present invention shown in FIG.
The results obtained after the subsequent treatment are shown in Table 1. [Table] The results shown in Table 1 indicate that raw water can be treated more effectively by using a pressurized water tank to circulate water through the tank than by using the conventional aeration pipe system. Table 2 shows the amount of biofilm attached to the contact material and the amount of biofilm that fell from the contact material and deposited at the bottom of the tank when the same wastewater was aerated using an aeration pipe and a pressurized water tank. [Table] (Note) The amount of biofilm is the value obtained by dividing the weight attached or fallen by the total water volume of all tanks.
From this result, when a pressurized water tank is used, there is less water falling to the bottom of the tank. Therefore, the frequency of periodic cleaning of the aeration tank, especially the pressurized water outlet, can be reduced. Effects of the Invention The technical effects obtained by the present invention will be specifically illustrated. (1) All of the microorganisms that proliferate in the wastewater are retained on the contact material, and the suspended solids that were previously mixed in and removed from excess sludge are also attached and decomposed. In addition, there is no need to return sludge, and aerobic and anaerobic treatments are performed continuously within the same microbial community.
There is no bulking phenomenon, which is a major problem with aerobic treatment using the desorbed liquid from anaerobic treatment using the conventional activated sludge method, and it can be operated in a nearly maintenance-free state without the need for dismantling due to excessive aeration. (2) Since the treatment efficiency is higher than that of conventional activated sludge, the treatment tank can be smaller, eliminating the need for sedimentation separation tanks, sludge storage tanks, sludge thickening tanks, dehydrators, etc., making it possible to replace existing equipment with insufficient capacity. Also suitable for improvement. (3) When the aeration tank has a multi-stage structure, it is possible to separate and propagate many types of microorganisms in each tank by taking into consideration the concentration gradient in each tank. It also has better processing ability than conventional methods. (4) Self-regulation of symbiotic effects by the excreta of various microorganisms can be expected, and high concentration wastewater of several thousand ppm can be reduced to 10 ppm.
It is also possible to process as follows. (5) Aeration of activated sludge in the conventional method is carried out solely for the purpose of supplying oxygen (DO) in the water that is consumed by microorganisms, etc., as well as providing a flow to the wastewater and measuring the effect of contact with attached bacteria. However, the present invention focuses on adjusting the amount of oxygen, that is, the amount of dissolved oxygen, for bacteria on the surface (aerobic) attached to the contact material and for anaerobic bacteria generated in the center.
In addition, a pressurized water-air precipitation method is adopted for oxygen supply and stirring to increase efficiency and require less air volume during operation. (6) Even with the conventional activated sludge method, difficult-to-decompose organic substrates that require long periods of sludge can be efficiently decomposed by the microbial symbiotic communities attached to the contact material, reducing treatment time (aeration (The tank is small) (7) Compared to the conventional catalytic oxidation method using a diffuser tube method, fine air bubbles are obtained, which increases air dissolution efficiency and enables efficient sludge treatment. Furthermore, in the aeration tube system, the diameter of the bubble outlet must be made small in order to obtain fine bubbles, which has the disadvantage of clogging the outlet. On the other hand, in the present invention, there is no need to reduce the diameter of the bubble outlet, and the problem of blockage does not occur. (8) Compared to the conventional aeration pipe method, less biofilm falls to the bottom of the tank during operation. Therefore, the frequency of periodic cleaning of the inside of the tank, particularly the pressurized water outlet, can be reduced. (9) Nitrifying bacteria and denitrifying bacteria can also grow actively, and even if regulations on nitrogen and phosphorus are enacted in the future, it will be possible to deal with it by appropriately separating the concentration gradient. (10) Even when there are long holidays such as during school holidays, there is little decrease in the activity of microorganisms, and there are no problems even during long power outages, and the rise time to return to a stable phase with re-aeration is short. .

[Brief explanation of drawings]

1-a, 1-b and 2-a, 2-b are a side view and a radial cross-sectional view, respectively, of a contact material used in the present invention. FIGS. 1 and 2 are a side view and a radial cross-sectional view, respectively, of a "contact material unit" used in the present invention. FIGS. 3 1 and 2 are a front view and a side view, respectively, of a contact material module in which a contact material unit is held and fixed to a frame. FIG. 4 is a cross-sectional view of an aeration tank that also uses a contact material module. 5. FIGS. 1 and 2 are flow sheets of an example of an apparatus for carrying out the conventional activated sludge method and the conventional catalytic oxidation method using a diffuser tube method, respectively. FIG. 6 shows an embodiment of a conventional catalytic oxidation method using a diffuser tube system. FIG. 7 shows an embodiment of a conventional catalytic oxidation method using a diffuser plate as a diffuser tube. FIGS. 8 1 and 2 show an example of a wastewater treatment apparatus of the present invention using a pressurized water tank and an ejector. FIG. 9 1 shows an example of the wastewater treatment apparatus of the present invention using an ejector.
FIG. 92 is a schematic diagram of an ejector used in the present invention. 1... Soft plastic pipe with core wire inserted through it, 2... Loop, 3... Untwisted bundled yarn, 4... Polyvinylidene chloride filament, b... Spiral pitch, c... Inner diameter, 21... Air diffuser pipe, 22... air diffuser plate, 34... ejector, 35... pressurized water tank, 41... discharge pipe.

Claims (1)

[Claims] 1. A system comprising (a) a device for pre-treating wastewater to be treated; (b) an aeration tank for aerating and mixing the pre-treated wastewater and microorganisms while bringing them into contact with each other; A wastewater treatment device that treats wastewater by mixing circulating water and air into an aeration tank, which comprises soft plastic pipes with core wires inserted into the aeration tank, arranged diagonally so as to intersect with each other. A plurality of untwisted bundled yarns and a non-twisted filament are made, and the filaments are pulled out from between the wound portions of the bundled yarns, and each filament is used to extend the soft plastic pipe in an independent radial direction outward in the radial direction of the soft plastic pipe. The wastewater treatment device is characterized in that a structure made of a contact material formed in a loop is inserted, and the mixture of the circulating water and the air is supplied into the aeration tank under high pressure. 2. The device according to claim 1, wherein the contact material is formed in a spiral shape. 3. The device according to claim 1, wherein the aeration tank has a multi-tank structure. 4 The pressure of the circulating water and the air is 5 to 10
2. The device according to claim 1, wherein the weight is in kg/cm ² . 5. The device according to claim 1, wherein the circulating water and the air are maintained at a high pressure by a combustor or a pressurized water tank. 6. The device according to claim 1, wherein the circulating water and the air are supplied at high pressure by a pump or an ejector. 7. The device according to claim 1, wherein the core wire is made of a rigid core material. 8. The device of claim 7, wherein the rigid core material is an aluminum alloy. 9. The apparatus of claim 7, wherein the inner diameter of the pipe is approximately equal to the outer diameter of the rigid core. 10. The device according to claim 7, wherein the pipe has a wall thickness of 0.5 to 1 mm. 11. The device according to claim 7, wherein the rigid core has a diameter of 3 to 5 mm. 12. The device of claim 1, wherein the diameter of the wound portion is between 20 and 35 mm. 13. Claim 1, wherein the untwisted filament is an untwisted polyvinylidene chloride filament.
Apparatus described in section.