KR20020094947A - Continuous Circulation Advanced Treatment by Anaerobic Contact Oxidation - Google Patents

Abstract

PURPOSE: An advanced contact oxidation process for removing nitrogen and phosphorus from wastewater which can treat microorganism in aerobic/anaerobic condition in separate contact and can reuse treated water is provided. CONSTITUTION: The process comprises a screening tank(1) which removes solid substance; a pretreatment tank(2) which removes substances that can not be treated biologically by flotation and settling; a flow equalization tank(3) which controls raw water; a v-notch(4) which controls flow rate when raw water flows into contact/aeration tanks; aeration tanks(5,7,9,11) which supply oxygen for preventing decomposition; contact tanks(6,8,10,12) in which raw water from aeration tank is supplied to every direction, the amount of organic substance is reduced by microorganism on contact media, and solid matter is perfectly decomposed by contact media; a settling tank(14); a filtration tank(15) which maintains aerobic condition in filtration tank by injecting oxygen and air and removes organic matter by microorganism in filter medium; a disinfection tank(17) which prevents secondary pollution; a discharge tank(18). 75% of contact media is aerobic microbe area and 25% is anaerobic microbe. The lower part of contact media is perfect aerobic condition and the center is aerobic/anaerobic condition and the upper part is anaerobic condition for multiple decomposition.

Description

Continuous Circulation Advanced Treatment by Anaerobic Contact Oxidation

In the future, it will strengthen the standard of water treatment facilities and efficiently reduce environmental pollutants and discharge them, and will play a role in the simplicity of land area maintenance and stable water quality management.

The present invention relates to a catalytic aeration water treatment apparatus based on a catalytic oxidation method for reducing contaminants in wastewater, and in particular, to achieve aerobic and anaerobic growth of aerobic microorganisms simultaneously in a single process during biological treatment. This method reduces the contaminants of raw water in the shortest time by repeating the process. It is also processed by back-up facility to process organic matter and nitrogen phosphorus contained in the discharge water at the same time. It relates to an oxidation aeration water treatment device and a catalytic oxidation aeration method.

The discharge of sewage is rapidly increasing due to industrialization, the increase of population, and the abundance of quality of life.In particular, due to the red tide, appeal of the sea, and the algae in rivers, the management of drinking water as well as the loss of fishery resources and environmental pollution Due to the inflow of social overhead capital, a tremendous amount of treasury losses is incurred. Therefore, a plan for efficiently coping with water quality management is needed.

In general, wastewater treatment facilities that have been developed and installed are focused on the removal of organic substances, and thus, another post treatment facility is installed to treat nitrogen and phosphorus. As a result, the establishment of comprehensive water quality management measures has passed. In addition, there is no solution due to the generation and increase of new pollutants caused by human life as well as nitrogen and phosphorus.

Currently developed contact aeration methods require microbial growth, cultivation and killing in the aeration tank, and oxygen supply devices coexist at the lower and surrounding areas of the contact material so that desorption of adherent microorganisms occurs and the relative capacity of the aeration tank should be large. The installation amount of the contact material is limited.

In addition, when inflow of solid materials, decomposition occurs, and sludge is generated, causing secondary soil pollution. Due to high consumption of power, secondary costs are incurred besides facility costs due to the burden of electricity costs.

The method of the present invention eliminates the factors of overload and low load by minimizing the occurrence of secondary additional costs, facilitating the decomposition of hardly decomposable organic substances, and dispersing the concentration of pollutant discharge time. The technical task is to simplify the complex facilities by allowing the treated water to be reprocessed and to remove bubbles caused by aeration, and to replace the facility with a backup device. to be.

In order to prevent secondary pollution, nitrogen, phosphorus and other contaminants are supplied as nutrients necessary for the growth of microorganisms, and if the target water quality is not satisfied, the facility can be reprocessed and the waste of household goods is recycled into contact tank contact materials. It is a technical task to seek to do so.

In order to suppress sludge generation, sludge and solid materials in each process are completely decomposed and moved to the next process, and sedimentation tanks, defoaming tanks, sludge thickening tanks, and sludge storage tanks are excluded from the process to reduce land area and facility cost, and It is a technical task to minimize secondary pollution caused by pollution and green tide.

If the maintenance manager's skills are not advanced and only normal mechanical repairs are made, it is a technical problem to make it possible to form a colony of microorganisms naturally so as to be suitable for each discharged water.

Water treatment is performed by aerobic microorganisms at the lower end of the contact media of the contact oxidizing tank, and the material generated during the metabolism process of aerobic microorganisms and the anaerobic microorganisms are proliferated at the upper part of the contact media to interact with the substances generated during the metabolic process of anaerobic microorganisms. The technical challenge is to promote the endogenous growth stage at the bottom of the contact tank.

In the process of filtering biologically treated water, a certain amount of oxygen is supplied to facilitate filtration, and to prevent anaerobicization, to prolong the life of the filtration material, and to simultaneously reduce suspended matter and organic matter.

It is a technical task to prevent sludge flow or the removal of solids in raw water tanks by treating all raw waters except for inorganic substances and oil components, such as sludge or raw materials, which are less than 1 specific gravity among raw waters. .

1A is a view showing a processing step of the present method

Figure 2a is an overall plan view of the present method

2B and 2C are cross-sectional views in plan view of the present method.

Figure 3a is a detailed cross-sectional view of each contact bath and aeration tank of the present method

Figure 4a is a detailed cross-sectional view of the filtering facility of the present method

The present invention is intended to achieve the object of the waste water treatment method and its facilities as follows to solve the above-mentioned technical problems.

Screen tank (1): Raw water, that is, raw water is generated from the discharge source, and organic materials and solid materials are generated at the same time as they enter the wastewater treatment facility. Therefore, this solid material is removed to prevent wear and damage of the machine and to smoothly process each process. It serves to stabilize the efficiency.

Pretreatment tank (2): Remove any contaminants that have not been removed from the screen tank, ie oils, detergents, and other biologically difficult materials by flotation or sedimentation, and then transfer them to the raw water tank.

Flow control tank (3): Also called a flow equalization tank, this is a process for storing raw water for a long time and supplying it to the contact aeration tank for the stable maintenance of the contact aeration tank.

v-notch (4): Facility to control flow rate when raw water is introduced into contact aeration tank by raw water pump or air lift.

Aeration tank (5,7,9,11): It is a facility that prevents decay and facilitates breathing of aerobic microorganisms by supplying constant oxygen during raw water and water treatment.

Contact tanks (6,8,10,12): Raw materials containing oxygen in the aeration tank are supplied steadily from the lower (or upper part) of the aeration tank without any vortex and evenly in all directions, and are organic substances by microorganisms that adhere to the contact media. In addition, the solid material is attached to the lower end or the contact medium, and is transported after being decomposed for a long time without being transferred to the next process. Three-quarters of the contact media are aerobic microbial populations, one quarter are anaerobic microbial populations, and the bottom of the contact media is aerobic coexistence and anaerobic microorganisms at the bottom of the contact media. It is a facility that allows decomposition of phosphorus pollutants.

Sedimentation tank (14): This sedimentation tank is a facility that is required when the movement of the contacting tank in the top-down tank is unnecessary process or abandonment tank.

Filtration tank (15): forming a membrane in the filtration tank, the treated water moved from the sedimentation tank or the last contact tank is filtered in a top-down manner, and then filtered upwardly, and by injecting a small amount of oxygen and air to prevent anaerobicization and inhabiting the microorganisms in the filter medium. By removing organic matter at the same time.

Small defoaming tank (16): A process for removing bubbles when abandoning the aeration tank. This method does not need to be separate because it can be removed by backup water.

Sterilization tank 17: A process for disinfecting to prevent secondary contamination from bacteria in the treated water.

Discharge tank (18): When discharge is possible due to natural flow, it can be handled by disinfection tank, but it is necessary for forced drainage.

In the above, the configuration of the inventive method is outlined for each process, but now each process is described in detail.

Raw water separated and settled from the pretreatment tank flows into the aeration tank through the flow adjustment tank.In this case, the BOD load is uniformly distributed and the aeration tank is composed of three to five rooms. This is to maintain the oxygen concentration in the contact tank when blocking the inflow. In addition, this function is to supply oxygen according to the flow of water, so it can be supplied in any tank. The final aeration tank is then supplied at the post-treatment stage. The aeration tank shall be manufactured in a circular shape and the diameter of the circle shall be one third to one third of the corresponding contact width, and shall be installed and stayed apart from one seventh to one tenth of the effective depth of the contact tank at the bottom. The time shall not exceed 30 minutes.

The contact materials in the contacting tank should be selected and placed in consideration of the BOD load amount (HBC, aluminum can, yogurt bottle, charcoal, cotton, sponge, fluidized bed filter, etc.). Therefore, the selection and quantity of contact materials should be installed to remove 50% in 1 contact tank, 40% in 2 contact baths, 30% in 3 contact baths, and 20% in 4 contact baths. . The width of each contacting tank is the same, and the ratio between the width and the effective depth is 1: 1.5 to 1: 2, and the lower edge is about one quarter of the width of the gang to make an arch shape. The water is naturally dispersed and moved to the contact tank, and the residence time is 1 hour 30 minutes to 2 hours 30 minutes. In addition, the installation method of the contact medium is the lower part of the filter medium is at least one half of the effective depth and the upper part is spaced 300mm to 400mm above the effective water level.

In case of installing sedimentation tank, sediment and turbid water at the bottom should be able to be transferred to columnar tank, first aeration tank, and abandonment tank at last stage. The air should be installed on a slope, but if it is unavoidable, install two diagonal sides to prevent drift.

The filtration tank is treated with water from the top and the first downward filtration is performed in the bottom-up filtration system to supply anaerobic oxygen to prevent anaerobicization and decompose organic matters at the same time. And the filter medium can also use the media of a contact tank. However, there should be at least three types of installations in each system, with a filtration rate of 100 liters per minute per cubic meter and a facility for backwashing and desorbed material with subsequent treatment.

Defoaming tanks, disinfection tanks, and discharge tanks are to be installed by conventional installation methods, with a residence time of at least 30 minutes.

The following will be described in detail based on the representation.

According to Fig. 1A, the screen tank 1, the pretreatment tank 2, the flow rate adjusting tank 3, the V-NOTCH 4, the first aeration tank 5, the first contact tank 6, and the second aeration tank 7 , Second contacting tank (8), third aeration tank (9), third contacting tank (10), fourth aeration tank (11), fourth contacting tank (12), rectifying pipe (13), sedimentation tank (14), filtration tank (15), the defoaming tank 16, the disinfection tank 17, and the discharge tank 18, but 3, 13, 14, 16, 17 may not be constituted.

In the treatment step, the waste water is removed from the source of pollution, and solids and contaminants are removed from the screen 1 through the conduit and flow into the pretreatment tank 2. The pretreatment tank has a residence capacity of more than 30 minutes, and the specific gravity of less than 1 material rises, and the specific gravity of one or more material is settled and then flows into the flow equalization tank (3). At this time, the passage from 2 to 3 should be piped like 65, and the lower opening should be arranged more than 1/2 of the depth, and the upper part should be spaced more than 300mm above the water level. Install an air diffuser in the pretreatment tank so that it can be agitated (79) for cleaning.

When the raw water separated from the pretreatment tank flows in, it is abandoned and diluted by the aeration device 80 and transferred to the first aeration tank 5 quantitatively through the V-NOTCH 4 by air lift or machine 30, and the surplus amount Is sent back to the flow control tank.

The raw water transferred from the flow rate adjusting tank flows into the first aeration tank 5 to be sufficiently abandoned by the bottom-up aeration device 81 to move the first contacting tank 6 through the lower end portion. At this time, the vortex must be prevented from occurring and the aeration oxygen concentration is adjusted so that the oxygen concentration becomes 0 near the third quarter point at the lower end of the first contact tank, and the treated water is transferred from the weir 24 through the transfer pipe 68. It moves to the 2nd aeration tank 7. In addition, by installing a reprocessing facility, that is, a backup device 49 for smoothing the respiration of microorganisms in the case of blocking the inflow of raw water and the load and the overload and overload, it is efficiently managed from external environmental factors.

The treated water introduced from the first contacting tank flows into the second aeration tank 7 to be sufficiently abandoned by the bottom-up aeration device 82 to move to the second contacting tank 8 through the lower end. At this time, the vortex must be prevented from occurring and the aeration oxygen concentration is adjusted so that the oxygen concentration becomes 0 near the third quarter point at the lower end of the second contact tank, and the treated water is transferred through the transfer pipe 70 from the weir 25. It moves to the 3rd aeration tank 9. In addition, by installing a reprocessing facility, that is, a backup device 50 for smoothing the respiration of microorganisms in case of raw water inflow and poor load and overload, it is efficiently managed from external environmental factors.

The treated water introduced from the second contacting tank flows into the third aeration tank 9 to be sufficiently abandoned by the bottom-up aeration device 83 to move to the third contacting tank 10 through the lower end. At this time, the vortex must be prevented from occurring and the aeration oxygen concentration is adjusted so that the oxygen concentration is 0 near the third quarter point at the lower end of the third contact tank, and the treated water is transferred through the transfer pipe 72 from the weir 26. It moves to the 4th aeration tank 11. In addition, by installing a reprocessing facility, that is, a backup device 51 to block the inflow of raw water and to facilitate the respiration of microorganisms in case of overload and overload, it is efficiently managed from external environmental factors.

The treated water introduced from the third contacting tank flows into the fourth aeration tank 11 to be sufficiently abandoned by the bottom-up aeration device 84 to move to the fourth contacting tank 12 through the lower end. At this time, the vortex must be prevented from occurring and the aeration oxygen concentration is adjusted so that the oxygen concentration is 0 near the third quarter point at the lower end of the fourth contact tank, and the treated water is transferred through the transfer pipe 74 from the weir 27. It moves to the rectification pipe 13 in the sedimentation tank 14, or the filtration tank 15. As shown in FIG. In addition, by installing a reprocessing facility, that is, a backup device 52 for smoothing the intake of microorganisms in the case of blocking the inflow of raw water and overloading and overloading, it is efficiently managed from external environmental factors.

The sedimentation tank is composed of square, and the rectification pipe 13 is installed at the center part, but the depth of the rectification pipe is up to 1/2 point of the depth, and the diameter is from 1/5 to 1/8 of the width of the sedimentation tank. The lower inclination angle is 60 degrees or more. The upper ware 28 is installed on a slope, but if it is unavoidable, it is installed symmetrically so that no drift occurs.

The filtration tank 15 has a filtration rate of 100 L / m 2 or more. The filtration method is a top-down and bottom-up method, but the filter media 23 is 3 to 5 types, and the oxygen supply 85 is provided at the bottom, and the back washing function and the desorption at the bottom are performed. Install air lifts (44, 54) or pumps for cleaning materials. The filtered water goes to 76 and goes to the defoaming tank

The defoaming tank 16 is moved to the disinfection tank 17 through the moving tube 77 and is discharged 64 while moving to the discharge tank 18 through 78. It should be installed by usual installation method, but the residence time should be more than 30 minutes.

The following describes in detail the aeration tank (5,7,9,11), the contact tanks (6,8,10,12), the filtration tank, the method and operation of the aeration tank, which are the core of the biological treatment method. Let's do it.

The aeration tanks 5, 7, 9, and 11 are installed in the center of the contact tanks 6, 8, 10, and 12 in a process dedicated to abandonment activities independently, and flow into the inlet pipes 66, 68, 70, and 72. Mixed with the treated water and backup (49, 50, 51, 52) or independent water is forcibly abandoned by the air injection machine (29), to help the microbial food intake by destroying the linkage of organic matter by the wild An air shredding network (95) is provided for resting oxygen dissolution, and the foreign matter is filled between the air shredding networks to crush the air to improve the oxygen dissolution rate and suppress the wave of the treated water. (68, 70, 72, 74) flows into the next process: aeration device (81, 82, 83, 84), backup device (49, 50, 51, 52), defoaming device (57, 58, 59, 60) ), And the structure and the wear (24, 25, 26, 27), and as an additional facility is composed of air injection pipe (35, 36, 37, 38, 39, 40, 41). Joe the sheep In this case, the amount of backup water is more than 200% of the raw water throughput.

Abandoned in the aeration tank sufficiently, the oxygen concentration is maintained at three quarters of the oxygen intake of the microorganisms attached to the contact media, and when the water supply is insufficient, or when the load is poor or overloaded, it is recycled, supplemented and supplemented by a backup device for stable water treatment. Keep it. Therefore, it is easier to use the automatic valve, and it should be installed at the center of the contact tank, but installed at the bottom of the contact tank from one seventh to one tenth of the effective depth, and the diameter should be one fourth to three minutes of the contact tank width. It should be 1, but the residence time should not exceed 30 minutes. The upper outflow weir should be circular, the diameter of weir should be about 1.5 times the diameter of the aeration tank, and the flow of the entire upper contact tank should be smooth. And the air diffuser should be upward to avoid the vortices caused by aeration, and it is possible to improve the aeration efficiency by making it as a membrane type.

The contact tanks 6, 8, 10, and 12 have an arched shape of the bottom edge 92 so that the sufficiently abandoned raw water flows freely through the lower part of the aeration tank and flows in all directions. The treated water is evenly distributed to all parts of the bottom of the contact tank. It moves to the next process through the weir of the aeration tank while being in contact with the contact media. The contact tank is composed of contact materials (19, 20, 21, 22) and the lower pedestal (91), the upper pedestal (90), the bottom edge portion 92 of the bottom, the aeration tank is a round and the contact tank is a square, consisting of three to five rooms However, the contact media is not a single species, but three or more types are arranged to increase the treatment efficiency.

The porosity of the contact material is more than 85%, and the specific surface area is 50% of raw organic matter in the first contact bath, the 40% of raw organic matter in the second contact bath, and 30% of the raw organic matter in the third contact bath. Four-contact tank secures the material and quantity of contact material to maintain 20% treatment efficiency of raw organic matter.Aerobic microorganism area in the lower layer, random microorganism area in the upper layer, anaerobic microorganism area in the upper layer, and desorption materials in the bottom are resistant growth stages. If the volume load is 0.3 ~ 1.4kgBOB.SS / ㎥ day, the removal rate of 96% or more is maintained at the maximum organic matter concentration of 450mg / l or less, influent water temperature of 12 ~ 40 ℃ and PH6 ~ 8. As a large quantity and variety of microbial colonies are formed, nitrogen oxides are reduced and phosphorus accumulates in microorganisms to block secondary pollution by passing through mechanism circulation cycles such as self-oxidation, catabolism, assimilation, and proliferation. React quickly to change.

The sludge generation rate for the inflow BOD and SS is 0.1∼0.2%, and all the degradable substances are decomposed to reduce the loss and the generation of sludge, so that the sedimentation tank is unnecessary.

The filtration tank has a residence time of about 1 hour, and the effluent treated in the aeration tank or sedimentation tank flows into the top-down filtration facility, is abandoned at the bottom, and then flows out through the bottom-up filtration facility. The filter medium is arranged in three or more types, the filtration speed is 100L / ㎡ or more, the backwashing water is 800 ~ 1200L / ㎡ or more, the backwashing speed is 35 ~ 70m / hour, and the sediment removal facility 54 is 1,5 times the backwashing speed. Comprising the above, the auxiliary device is installed in the separation membrane 89 and the passage 93, and the media support 94 is formed at two-thirds of the effective depth. Form 5 to 5 layers of media 3 with porosity of 75% or more with activated carbon, sand, HBC, titanium, anthracite, crushed stone and gravel.

As described above, this method has a volume load of 0.3 ~ 1.4kgBOB.SS / ㎥ days, which is superior to the existing anaerobic and aerobic complex processes and aerobic treatment methods, resulting in relatively reduced costs and the absence of sedimentation tanks, sludge concentration tanks, and defoaming tanks. Since it requires less land area and sludge generation rate is 0.1 ~ 0.2% compared to the influent organic matter, there is no generation of secondary pollutants and high removal rate of nitrogen and phosphorus compounds. It can have the effect of preventing the rusting phenomenon caused by it.

In addition, the contact material of the contact tank may have the effect of recycling waste. It is possible to secure a certain porosity among materials without corrosiveness and abrasion in our daily routines such as waste cotton, waste cans, and yogurt waste bottles.

And the sewage treatment facility is effective in treating this, because the large amount of raw water is discharged at a certain time and the load fluctuation according to the day of the week. It is a facility that can handle various kinds of contact materials and reprocessing, and it is easy to adapt to load fluctuations, and many kinds of microbial communities are formed, so that stable water quality of more than 96% of organic matter removal rate can be obtained under inflow water quality of 450mg / l or less.

The facilities that supply oxygen and the space where microorganisms work are separated from each other, eliminating the harmful effects of interactions, so that stable maintenance is possible, and the maintenance technology is not hindered without specialization. It is an advantage that the maintenance is simple by measuring the oxygen concentration in the contact tank and operating the recirculation treatment facility, that is, the backup facility.

Layers of various types of filter media were formed in the aeration-type top-down and bottom-up filtration facilities due to natural flow to remove fine suspended substances and reprocess organic matter by aerobic microorganisms and to remove residual nitrogen and phosphorus. It is characteristic.

The secondary cost burden was reduced by securing the same aeration efficiency, that is, oxygen dissolution rate, and reducing the power cost with a small power.

Claims (17)

Wastewater treatment facilities formed in the previous stage where wastewater flows into the screen (1) through the inlet pipe and is moved to the flow control tank (3) through the pretreatment tank (2), and the aeration device (79,80) and other auxiliary facilities in the facility Facility with (61,62,63,65,30,33,34) Independent aeration tanks (5, 7, 9, 11) for supplying the required amount of oxygen to the contact material of the contact tank are installed, and the recycling treatment facilities (49, 50, 51, 52) and its auxiliary facilities (24, 25, 26, 27, Facilities with 35,36,37,38,39,40,41,81,82,83,84 The method of claim 2 The aeration tank (5, 7, 9, 11) consists of three to five rooms, the effect of preventing desorption of contact material adherence material by abandonment of the aeration tank and the back-up facility for recycling the treated water and delivering oxygen in the contact material ( Aeration tank to improve oxygen dissolution rate by installing 49,50,51,52 and attaching air shredding network 95 The method of claim 3, The inflow pipes 66, 68, 70, 72 of the aeration tanks 5, 7, 9, 11, and the treated water of the contact tanks pass through the weirs 24, 25, 26, 27, and outlet pipes 68, 70, 72, 74. The diameter of the facility and the aeration tank moved to the contact tank should be one third to one third of the width of the contact tank, but the residence time should not exceed 30 minutes, and it should be separated from the bottom by one tenth to one seventh of the depth. Independent aeration tanks where the diameter of weir is 1.5 times the diameter of the aeration tank. The method of claim 3, An air shredding network 95 is installed in the aeration tank for improving the solubility of oxygen, and a separate aeration tank is installed to easily maintain the oxygen concentration by filling the fluid therebetween and to facilitate the decomposition of organic matter by wild air. Abandoned structure to obtain wastewater treatment facility and super-dissolved oxygen dissolution rate Facility equipped with contact tanks (6, 8, 10, 12) and internal contact materials (19, 20, 21, 22) for decomposing treated water containing oxygen in aeration tank The method of claim 6 The contact tank 6, 8, 10, 12 is composed of three to five chambers having the same capacity, the contact member (19, 20, 21, 22) is densely installed and the contact tank is installed three to five kinds of contact member Wastewater treatment facility with treatment room ratio of 5: 3: 2 for 3 rooms, 4: 3: 2.5: 1.5 for 4 rooms, and 3.5: 2.5: 2: 1: 1 for 5 rooms The method of claim 7, 3 to 5 types of contact materials (19, 20, 21, 22) are installed in relation to the above treatment efficiency ratio, and contact materials (e.g. waste cans, required leto lung disease, waste cotton, etc.) having a porosity of 85% or more for waste recycling Wastewater treatment facility installed and maintaining 140% of total treatment efficiency The method of claim 7, The contact material in the contact tank is installed in the area excluding the aeration tank (5, 7, 9, 11) in the center, and the lower part forms a pedestal 91 at the half point or more of the total depth, and the upper part is 300 to 400 mm lower than the water surface. A fixture 90 is installed to block the flow of contact material spaced apart from each other, and the bottom edge 92 has an arched shape to smoothly distribute the treated water. Oxygen contained by the aeration of the aeration tank is adjusted to zero at three quarters of the contact material (19, 20, 21, 22) to simultaneously catalyze, assimilate, proliferate and endogenous by aerobic microorganisms, random microorganisms and anaerobic microorganisms. Facility that minimizes green algae, red tide and soil pollution due to secondary pollution, such as eutrophication, by decomposing organic matter, reducing nitrogen and phosphorus compounds by growth, and suppressing sludge generation Facility in which organic matter is decomposed in the contact tank and the treated water passes through the settling tank 14 or the filter tank 15 is installed without placing the settling tank. The method of claim 11, Filtration facility 15 in which the treated water treated in the contact tank 12 or the settling tank 14 is transferred to the upper part of the filtration tank, and the first stage top-down filtration proceeds and the second stage bottom-up filtration is processed. The method of claim 12, The filtration facilities of the filtration tank are separated by the upper and lower separators (89), and there is a barrel (93) in the center for the maintenance of the auxiliary facilities and the improvement of filtration efficiency. The filter media pedestal 94 is installed at one-half point of the layer, and a layer is formed of three to five or more kinds of filter media 23. The filtration rate is 100L / m 2 or more and the backwash water is 800 to 1200L / m 2 or more. Filtration facility to filter by The method of claim 12, Filtration facility to install anaerobic facilities (85) in the filtration tank to prevent anaerobicization and to simultaneously decompose organic matter with suspended solids, and to facilitate backwashing (55) and removal of sediments (43). The wastewater treatment facility which consists of the defoaming water tank 16, the disinfection tank 17, the discharge tank 18, or abbreviated 16 and 17, and the accompanying apparatus which passed through the filtration process, and installed the accompanying apparatus. Inflow volume load of wastewater capable of biologically decomposing organic matter 0.3 ~ 1.4kgBOD.SS / ㎥ day Wastewater that maintains organic removal rate of 96% or more when concentration is 450mg / l or less, influent water temperature 12 ~ 40 ℃, PH 6 ~ 8 Treatment facility The entire organic material passed through the screen is introduced into the aeration tank so that the solid material does not move to the next process at the bottom of the contact material or the bottom of the contact tank, and decomposes for a long time to suppress the generation of sludge, and the detached adherent material is completely oxidized and then moved to the next process. Wastewater treatment facility to make sludge generation 0.1 ~ 0.2% of concentration of influent organic matter