JP2000005779A - Device of preventing clogging of filter media in biological filter tank and method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent clogging of filter media in a biological filter tank of a sewage septic tank. SOLUTION: At the time of back-washing the biological filter tank, hollow filter media in a filtering treatment zone and hollow filter media in an aerobic treatment zone are washed by fluid contact caused by an aeration stirring action from a back washing device G, and also a portion of the hollow filter media in the filter treatment zone is floated on the upper side of a diffuser S, and a portion of the hollow filter media in the aerobic treatment zone is settled at the lower side of the diffuser S to be mixed, and these processes are repeated, thus the hollow filter media in the tank are exchanged up and down properly and the treating function is converted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for preventing clogging of a filter medium in a biological filtration tank of a sewage purification tank for treating organic sewage.

[0002]

2. Description of the Related Art Conventionally, as a sewage purifying tank using a biological filtration tank, there are known "biological filtration method and sewage purifying tank using granular carrier" described in JP-A-5-309382, and
No. 248584 has proposed a “sewage purification tank”.

[0003] First, in the case of the biological filtration tank in the former sewage purification tank, an aerobic treatment chamber for accommodating a particulate carrier in the upper chamber of the biological filtration tank and performing aerobic biodegradation of the primary treated water is formed. In addition, a filtration processing chamber for accommodating the granular carrier in the lower chamber and performing physical filtration of aerobic treated water is defined. More specifically, a diffuser is piped to the lower part of the aerobic treatment chamber, the bottom is closed with a porous member, and the upper and lower parts of the filtration treatment chamber are closed with a porous member. A backwashing device is piped, and a drainage pipe for backwashing treatment water is piped to an intermediate boundary room between the upper chamber and the lower chamber.

[0004] Next, in the case of an aerobic filter bed tank in the latter sewage purification tank, that is, a biological filtration tank, the intermediate boundary chamber disclosed in the former is eliminated, and the upper chamber and the lower chamber are directly formed by a porous member. In addition, the upper part of the upper chamber is closed with a porous member, and a discharge pipe for backwash water is provided in the lower chamber of the biological filtration tank. In this case, the porous member is disposed in the upper portion, the middle portion, and the lower portion, so that the porous member is divided into an upper chamber and a lower chamber.
Granular carriers are charged into both the upper and lower chambers.

[0005] In the above biological filtration tanks,
Normally, the primary treated water flowing into the upper chamber promotes the activity of the aerobic microorganisms attached to the granular carriers placed in the upper chamber due to aeration from the air diffuser, and is aerobic to the primary treated anaerobic treated water. Treated to remove sludge and SS from granular carriers
The aerobic treated water containing water and the like is filtered by passing through the granular carrier stored in the lower chamber. In addition, at the time of backwashing, by aeration from the backwashing device provided in the bottom chamber, the granular carrier contained in the lower chamber and the granular carrier contained in the upper chamber are subjected to bubbling washing, whereby biofilm attached to the granular carrier is removed. It deals with the removal of the surplus by stripping and the removal of SS, sludge and the like accumulated between the granular carriers.

[0006]

However, in order to increase the contact area of the granular carrier as much as possible and to enhance the processing efficiency, a concave portion or a hollow hole is formed inside the granular carrier. Therefore, in the case of the filtration treatment using the granular carrier placed in the lower chamber, the SS or the sludge clogged in the porous portion such as the concave portion or the hollow hole is usually backwashed once a day for several minutes. In the case of aeration at the time, there is a limit to the cleaning performance up to the inside of the carrier, and as a result, the cleaning effect at the time of backwashing gradually decreases, and as a result, the filtering performance by the granular carrier put in the lower chamber , Which eventually leads to blockage and anaerobic or short-circuit flow.

[0007] In this respect, the aerobic treatment by the granular carrier put in the upper chamber is performed by constantly diffusing the air from the lower part by a diffuser, whereby the granular carrier put in the upper chamber flows, and the swirling flow causes By the carriers being in contact with each other, the excess of the adhered substances is peeled and removed, and clogging or the like due to unnecessary adhesion to the porous portion inside the carrier is prevented, which is accompanied by a kind of cleaning effect. . Therefore, at the time of backwashing, when a strong aeration action is performed as compared with the aeration, the backwashing of the adhered substance to the porous portion or the like of the granular carrier is performed as compared with the case of the granular carrier placed in the lower chamber. There is no significant drop in the effect.

Considering the above phenomenon, in the case of the conventional apparatus, the upper chamber and the lower chamber are partitioned by a porous member, and the granular carrier put in the upper chamber functions only for aerobic treatment,
Further, the granular carrier put in the lower chamber is configured to function only for the filtration treatment, which is considered to be a cause that is likely to cause blockage during the filtration treatment.

[0009]

Accordingly, in the present invention, in order to solve the above-mentioned problems, a porous member for preventing the floating of a filter medium is provided above a biological filtration tank in a sewage purification tank, and a biological filtration tank is provided. A filter member settling prevention porous member is disposed below the filter member, a diffuser is piped between the upper and lower porous members at a position close to the filter medium settling prevention porous member, and the synthetic resin put in the compartment is provided. A hollow filter medium is passed between the air diffusers to make it free to flow in the room, and a backwashing device is piped to the bottom room of the biological filtration tank, and the inlet of the return airlift pipe for pumping up the backwashing water is connected to the hollow filter. The present invention has provided a device for preventing a filter medium from being blocked in a biological filtration tank.

In short, the porous member for partitioning the upper chamber and the lower chamber in the conventional apparatus is eliminated, and the compartment is provided with
In place of the granular carrier, a hollow filter medium made of synthetic resin is accommodated, and the entire amount of the hollow filter medium is allowed to flow in the processing chamber.In normal times, the primary treated water flowing into the biological filtration tank is discharged from the air diffuser. The aerobic action causes the hollow filter medium in the aerobic treatment zone on the upper side of the air diffuser to flow, thereby performing aerobic treatment by the aerobic microorganisms attached to the hollow filter medium and dispersing the aerobic treated water. Filtration is performed by the hollow filter medium that settles and stays at the lower side of the gasifier, and at the time of backwashing, due to the aeration from the backwasher, the entire amount of the stored hollow filter medium passes through the diffuser and flows through the processing chamber. To stir and wash.

In particular, in claim 2, in addition to the above constitution, when the biological filtration tank is backwashed, the hollow filter medium in the filtration zone and the hollow filter medium in the aerobic zone are fluidly contacted by the aeration effect from the backwashing device. Washing is performed by aeration and agitation, and a part of the hollow filter medium in the filtration processing zone is floated to the upper side of the air diffuser, and a part of the hollow filter medium in the aerobic processing zone is moved to the lower side of the air diffuser. By sedimenting and stirring and mixing, and by repeating this, the hollow filter medium in the processing chamber is switched up and down moderately, thereby making the processing function freely convertible, thereby preventing the filter medium from being blocked in the biological filtration tank. It is.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to schematic diagrams of a sewage treatment tank T shown in FIGS. The inside of the sewage purification tank T is divided into a plurality of treatment tanks in the order of the sewage treatment process from the inflow pipe 1 side into which the sewage flows, to the treated water discharge pipe 2 side. A tank A, an anaerobic filter bed tank B, a biological filtration tank C, a treatment water tank D, and a disinfection tank E are provided.

In the contaminant removal tank A, the inflow sewage from the inflow pipe 1 is caused to flow down into the tank via the inflow baffle 3 to separate contaminants and oils and fats mixed in the inflow sewage under anaerobic conditions into solid-liquid separation. Among them, the impurities are settled at the bottom of the tank,
The anaerobic treatment water is caused to flow upward in the advection baffle 4 and is transferred to the anaerobic filter bed tank B from the transfer opening 6 above the partition wall 5 with the next anaerobic filter bed tank B.

In the vicinity of the center of the anaerobic filter bed tank B, a porous net 7 is disposed above and below, and an anaerobic filter bed R containing a spherical filter medium 8 therein is installed in a immersed state. Floor R
The anaerobic microorganisms inhabit and are active.
Therefore, the anaerobic treated water that has flowed into the anaerobic filter bed B from the advection opening 6 passes through the anaerobic filter bed R, is anaerobically treated by anaerobic microorganisms, and then flows down to the bottom chamber 9. . The anaerobic treated water flows up the advection baffle 10 also serving as a cleaning port, and flows from the advection opening 12 above the partition 11 with the biological filtration tank C to the next biological filtration tank C.

Here, the structure of the biological filtration tank C constituting a main part of the present invention will be described. Reference numeral 13 denotes a porous member for preventing the floating of the filter medium disposed above the biological filtration tank C, and reference numeral 14 denotes a biological filtration tank C.
A filter member settling prevention porous member disposed in the lower part of
An engaging step 1 protruding from the inner wall surface of the biological filtration tank C at the upper and lower positions.
5 and thereby the upper and lower porous members 13, 14
A processing chamber F is formed between them.

S denotes an air diffuser, which is disposed in a flat lattice form between the porous members 13 and 14 at upper and lower positions near the porous member 14 for preventing the settling of the filter medium.
Is piped vertically upward along a position close to one partition 11, and the upper end thereof is connected to an air supply main pipe 17,
A connection pipe with an air blower (not shown) is provided at an air supply port 18 at the base end thereof, and air is always supplied.

X is a hollow cylindrical filter medium made of a synthetic resin (hereinafter referred to as a hollow filter medium). More specifically, as shown in FIG. 6, the cylindrical medium has an inner and outer diameter of about 12 to 14 mmφ and has a high height. Of about 14 to 15 mm and a wall thickness of about 1 mm, the specific gravity of which is slightly
± 0.07 ”. This is because the hollow filter medium X is given a property of slowly settling in the treated water, so that the hollow filter medium X in the processing chamber F can be diffused with a relatively small amount of air.
The specific gravity is adjusted from the viewpoint of coping with the smooth and gradual liquidation.

Further, as shown in FIG.
The processing chamber F is accommodated up to a position of about 75 to 85% of the depth. This prevents smooth fluidization at the time of backwashing when the filling ratio of the hollow filter medium X is set to the above ratio or more.
When the backwashing efficiency is reduced, and conversely, when the filling ratio is lower than the above range, the amount of microorganisms held in the hollow filter medium X charged decreases, and the treatment efficiency decreases. Is preferably maintained.

G is a backwashing device which is installed in the bottom chamber 20 of the biological filtration tank C in a horizontal manner in the form of a flat lattice, and the backwashing air pipe 2
1 is piped vertically upward along the inner wall surface of the U-shaped partition wall 22 for partitioning the tank 1 from the other treated water tank D, and the upper end thereof is connected to the backwashing air supply main pipe 23 and the base end thereof. Air outlet 2
4 is connected to a connection pipe for a backwash blower (not shown). The backwashing blower is driven and controlled by a timer or the like, and is normally driven for several minutes to about several tens of minutes during the midnight time when the inflow of sewage is small.

Reference numeral 25 denotes an air lift pipe for returning the backwashed sludge water, which is provided upright at a position on one side of the back surface of the partition wall 22 so that an inlet 26 at the lower end thereof faces the bottom chamber 20.
An air-lift air supply pipe 27 is provided at a position adjacent to the return air-lift pipe 25, and the lower end thereof is connected to the return air-lift pipe 2.
5 is connected to the lower end position, and the upper end is
3 piping. This is because, at the time of backwashing, the backwashing treatment water that settles in the bottom chamber 20 is sucked from the inflow port 26 by the airlift pumping action by sending air from the airlift air supply pipe 27 to the return airlift pipe 25 to return the return airlift pipe. 25 is raised and pumped up.

Reference numeral 28 denotes an air lift pipe for circulating the treated water secondary-treated in the biological filtration tank C, which is provided upright at the other side of the rear face of the partition wall 22 and which has an inflow port 29 at the lower end thereof.
2, an air lift air supply pipe 31 is provided so as to face the advection opening 30 formed at the lower end of the circulating air lift pipe 28 and adjacent to the circulating air lift pipe 28. And the upper end thereof is connected to the air supply main pipe 17 for air diffusion. This is because the small amount of filtered water flowing down to the bottom chamber 20 is always supplied from the air lift air supply pipe 31 to the circulation air lift pipe 28 by the air lift pump action, regardless of the time of air diffusion or back washing. Then, the air is sucked from the inflow port 29 and the return air lift pipe 28 is raised to be pumped up.

Reference numeral 32 denotes a sewage return pipe for backwashing treatment water laid horizontally at the upper end of the return air lift pipe 25, and reference numerals 33 and 34 denote a circulating amount meter and a circulation pipe laid horizontally at the upper end of the circulation air lift pipe 28. A return pipe, which is piped at both left and right sides of the upper part of the tank with a space therebetween, and the leading end of which is connected to the impurity removing tank A.
The sludge treated water pumped up from the return air lift tube 25 at the time of backwashing,
At any time, the treated water pumped from the circulation air lift pipe 28 is returned to the impurity removing tank A.

Normally, the primary treated water that has flowed into the biological filtration tank C is subjected to aeration and agitation from the diffuser S as shown in FIG. The hollow filter medium X in the treatment zone M is constantly gently flowed, aerobicly treated by aerobic microorganisms attached to the surface of the hollow filter medium X and the inside of the filter medium, and oxidatively decomposed of organic substances.
At the same time as the biological treatment, the flowing hollow filter media X come into contact with each other, adhere to the surface of the hollow filter media X, and the biofilm formed by the microorganisms is appropriately peeled, so that the biofilm is held in an appropriate amount. At this time, since the hollow filter medium X in the filtration processing zone N below the depth position of the air diffuser S is not affected by the air diffusion action, it does not fluidize and the porous member 1 on the lower side does not flow.
4 and the air diffuser S are settled and settled in a filled state.

Next, the aerobic treated water biologically oxidatively decomposed by aeration and agitation is subjected to aerobic treated water in the filtration treatment zone N by the hollow filter medium X filled in the lower part from the aeration device S. By trapping suspended substances, excess biofilm peeled off from the hollow filter medium X, and other SS components, a physical filtration process is performed. The treated water that has passed through the filtration treatment zone N is supplied to the bottom chamber 20 of the biological filtration tank C.
After flowing down, the water flows through the advection openings 30 formed at the left and right sides of the lower end of the partition wall 22 and is sent out to the next treated water tank D.

At midnight when there is no inflow of sewage, the backwashing blower is driven and the aeration from the backwashing device G in the bottom chamber 20 gushes. Then, as shown in FIG. 8, first, the hollow filter medium X in the filtration zone N starts flowing at once by the aeration action from the backwashing device G, and the hollow filter medium X in the filtration zone N starts.
The sludge and SS accumulated inside the filter medium and inside the filter medium are fluidized, and the fluid is contacted by a strong aeration and agitation action compared to the normal aeration and agitation action. The backwashing process is performed on the hollow filter medium X in the zone N.

Backwashing treatment water containing excess biofilm, sludge, SS and the like separated by the backwashing is pumped up from the inlet 26 of the return airlift tube 25, and the inlet of the circulation airlift tube 28. Pumped from 29,
The wastewater is returned to the contaminant removal layer A from the wastewater return pipe 32 and the circulation return pipe 34, respectively, and is subjected to reprocessing.

At this time, a part of the hollow filter medium X in the filtration zone N floats up to the upper side of the diffuser S and swirls, and a part of the hollow filter medium X in the aerobic zone M is dispersed. Air device S
, The hollow filter medium X in the filtration zone N and the aerobic zone M are mixed appropriately and in a mixed state, and again the aeration and agitation by the air diffuser S are performed in the aerobic zone N. And the filtration process in the filtration zone N is performed. Therefore, by repeating the aeration and stirring by the backwashing device G, the hollow filter medium X in the filtration processing zone N and the aerobic processing zone M is appropriately switched up and down, whereby the role of the processing function for the hollow filter medium X is exchanged. This effectively prevents clogging of the filter medium in the processing chamber F of the biological filtration tank C and effectively prevents anaerobicization of the filtration processing zone N.

The biologically treated water (secondary treated water) that has flowed down to the bottom chamber 20 of the biological filtration tank C flows into the treated water tank D after flowing through the advancing opening 30 with the next treated water tank D. The supernatant is disinfected in the disinfection tank E and then discharged from the discharge pipe 2.

[0029]

The present invention provides an apparatus and a method for preventing a filter medium from clogging in a biological filtration tank as described above, and provides the following effects. (1) Since the hollow filtration medium X in the aerobic treatment zone N slowly flows on the upper side of the aeration device S among the hollow filter media X accommodated in the processing chamber F of the biological filtration tank C, Uniform contact with the primary treated water flowing into the inside is performed, and at this time, a large number of microorganisms inhabit the inside and outside surfaces of the hollow filter medium X and the inside of the filter medium, and the aerobic decomposition of organic substances in the wastewater is smoothly performed. . (2) In addition, since the hollow filter media X flow through the aerobic treatment zone M, the hollow filter media X come into contact with each other to perform an excessive peeling treatment, and the microorganisms adhering to the hollow filter media X are well retained. Therefore, the aerobic treatment is always performed stably. (3) In addition, the inflowing primary treatment water is diffused and agitated, so that suspended substances not removed in the primary treatment stage are
By flowing together with the hollow filter medium X, it is uniformly decomposed, which contributes to preventing the filter processing zone N from being blocked. (4) Further, the filtration treatment is performed by the hollow filtration material X filled in the filtration treatment zone N at a position lower than the aeration device S, so that the floating filtration material in the aerobic treatment zone M is formed by floating substances and diffused agitation. Biofilms and the like that have detached from X are removed,
Very clear treated water is obtained. (5) In the filtration zone N located below the air diffuser S, the trapped suspended substances and the like are washed and removed very efficiently by the aeration and stirring action of the backwashing device G. (6) In particular, at the time of backwashing, the hollow filter medium X in the filtration processing zone N and the hollow filter medium X in the aerobic processing zone M above the diffuser S are replaced and replaced at an appropriate ratio. This is extremely excellent in preventing the filter medium from clogging in the filtration processing zone N and preventing the anaerobic treatment.

[Brief description of the drawings]

FIG. 1 is a side view showing the overall outline of a sewage treatment tank.

FIG. 2 is a plan view of a sewage purification tank.

FIG. 3 is a side view showing a piping system of the biological filtration tank, in which a return airlift pipe and a circulation airlift pipe are shown in a state in which the drawing is misaligned left and right in the drawing.

FIG. 4 is a perspective view showing a biological filtration tank.

FIG. 5 is a plan view showing an upper pipe of the biological filtration tank.

FIG. 6 is a perspective view of a hollow filter medium.

FIG. 7 is a diagram showing a state of swirling flow during aeration in a biological filtration tank.

FIG. 8 is a view showing a state of swirling flow during backwashing.

[Explanation of symbols]

 T Wastewater purification tank A Contaminant removal tank B Anaerobic filter bed tank C Biological filtration tank D Treatment water tank E Disinfection tank F Processing chamber S Aerator X Hollow filter material G Backwasher R Anaerobic filter bed M Aerobic treatment zone N Filtration zone REFERENCE SIGNS LIST 1 inflow pipe 2 discharge pipe 3 inflow baffle 4, 10 advection baffle 5, 11, 22 partition wall 6, 12, 30 advection opening 7 porous net 8 spherical filter medium 9, 20 bottom chamber 13, 14 porous member 15 engaging step section 16, 21, 27, 31 Air supply pipe 17, 23 Air supply main pipe 18, 24 Air supply port 25, 28 Air lift pipe 26, 29 Inlet 32 Sewage return pipe 33 Measuring device 34 Circulation return pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kei Takahashi 33, Yamanoseki-machi, Chiyuri-shi, Aichi F-term in Water Environment Research Laboratory, Fujilean Industry Co., Ltd. 4D003 AA08 AB09 BA01 CA08 DA11 DA19 DA20 DA22 EA01 EA15 EA30 FA05

Claims (2)

[Claims] 1. A porous member for preventing the floating of a filter medium is disposed above a biological filtration tank in a sewage purification tank, and a porous member for preventing settling of a filter medium is disposed below a biological filtration tank. A diffuser is piped at a position near the porous member for preventing the settling of the filter medium, and the hollow synthetic resin filter medium placed in this compartment passes between the diffusers and is made free to flow in the room. An apparatus for preventing a filter medium from being clogged in a biological filtration tank, wherein a backwashing device is provided in a bottom chamber of the filtration tank and an inlet of a return airlift pipe for pumping up the backwashing water is exposed. 2. A porous member for preventing floating of a filter medium is disposed above a biological filtration tank in a sewage purification tank, and a porous member for preventing settling of a filter medium is disposed below a biological filtration tank. A diffuser is piped at a position near the porous member for preventing the settling of the filter medium, and the hollow synthetic resin filter medium placed in this compartment passes between the diffusers and is made free to flow in the room. A backwashing device is connected to the bottom chamber of the filtration tank, and the inlet of a return airlift pipe for pumping up the backwashing water is faced. By diffusing the hollow filter medium on the upper side of the air diffuser by the diffusing action from the aerobic microorganisms attached to the hollow filter medium, the aerobic treatment is performed, and the aerobic treated water is used for the air diffuser. Filtration treatment by hollow filter material staying on the lower side At the time of back washing of the biological filtration tank, the hollow filter medium having the filtration function and the hollow filter medium having the aerobic treatment function are brought into fluid contact with each other by the aeration effect from the back washing apparatus, and the washing treatment is performed. A part of the hollow filter medium is floated to the upper side of the aeration device, and a part of the hollow filter medium of the aerobic treatment function is mixed by settling to the lower side of the aerator, and this is repeated. A method for preventing clogging of a filter medium in a biological filtration tank, wherein the hollow filter medium is exchanged for its processing function by being switched upside down.