JP3378628B2 - Filtration and denitrification equipment for sewage and filtration and denitrification method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter denitrification apparatus and a filter denitrification method for effectively filtering out organic SS and nitrogen from various organic wastewater, especially sewage.

[0002]

2. Description of the Related Art Conventionally, as a technique for filtering SS from wastewater such as sewage, a deep-layer filtration method using a granular mineral such as sand or anthracite as a filter medium has been known. When trying to remove SS, it was not practical because it was heavily clogged. Further, a filtration method using various granular solids such as plastic particles other than the above-mentioned granular mineral as a filter medium has been studied, but if the filter medium particle size is increased to reduce clogging, the removal rate of SS deteriorates. The contradiction occurred. In particular, since organic SS contained in sewage or the like has a strong adhesive force, a technique which can satisfy the contradictory requirements of high SS removal rate and less clogging for such sewage and the like has not been put into practical use. In order to deal with the eutrophication problem in recent years, a method capable of effectively performing filtration and denitrification treatment of organic SS with the same filtration device is desired, but such a filtration denitrification device has been sufficiently put into practical use. Absent.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an organic SS
The present invention provides a sewage treatment apparatus capable of simultaneously performing filtration and denitrification treatment, and having high efficiency of SS removal and denitrification treatment and simultaneously satisfying contradictory requirements that clogging is extremely small. The present invention also presents a method for achieving the desired processing effect by the device. In particular, it is an object to provide a filter denitrification apparatus and a filter denitrification method for sewage that can simultaneously perform filtration and denitrification of sticky organic SS.

[0004]

Means for Solving the Problems The above problems can be achieved by the filtration denitrification apparatus and filtration denitrification method of the present invention described below. That is, the above problems are as follows: (1) The inside of the tank is divided by porous members to form processing chambers in upper and lower stages, and further, the lower part of the porous member is a precipitation part and the upper part is a porous member. A water outflow section, a sewage supply apparatus and a cleaning gas supply apparatus in the precipitation section, and a sediment discharge apparatus in the bottom of the tank, and at least the lower processing chamber has a hollow cylinder with a specific gravity close to that of water. A floating packing layer of granular particles is provided to form an SS filtration layer, and a space is formed below the SS filtering layer . The upper processing chamber has a floating packing of particles that are smaller than the hollow cylindrical particles and floatable in water. Denitrification with layers
A base layer is formed, and a space portion is formed below the base layer.
Sewage filtration denitrification apparatus characterized in that a containing NO _X -N water supply device for supplying water containing _X -N,

And (2) in a method of contacting sewage with granules on which microorganisms are immobilized and performing filtration and denitrification, the floating packed bed of hollow cylindrical granules having a specific gravity close to that of sewage.
After flowing SS upwardly to filter SS, the floating packed bed
NO _X in provided in the upper, the smaller than the hollow cylindrical granules, and introduced up-flow to the floating packed bed of floating of the granules in water
With reducing -N nitrogen gas, Ru is accomplished by filtration denitrification process wastewater, which comprises processing while supplying water containing NO _X -N in the upper floating filling layer.

Only by adopting such a packed bed, a granular structure and a treatment method, the conflicting requirements that the SS removal efficiency is high and the clogging is extremely small even in the case of raw water containing a large amount of sticky SS. Can be satisfied at the same time. Here, NO _X -N is a generic term for nitrate nitrogen NO ₃ -N and nitrite nitrogen NO ₂ -N. Further, the porous water-permeable member is a member such as a punching plate, a grating (net), a net, etc. on the entire cross-section of the filter bed so as not to mix the upper and lower layers of the filled filter medium. Furthermore, even if the gas supply device is stopped during the treatment of the wastewater, it slightly diffuses the oxygen-containing gas,
You may perform aerobic denitrification processing. Of course, it does not prevent the diffusion of oxygen-free gas.

[0007]

(Specific Configuration Example) FIG. 1 shows a filter denitrification apparatus of the present invention. Hereinafter, a configuration example of the present invention will be described with reference to FIG. 1 and then an operation will be described, but the following configuration example and description of the operation do not limit the present invention.

FIG. 1 shows an example in which the filter denitrification device of the present invention is composed of two upper and lower stages. The present filtration denitrification apparatus 1 has a porous water-permeable member 3 that is water-permeable from the bottom,
The porous water-passing member 4 and the porous water-passing member 2 separate the sedimentation portion C, the treatment chamber D, the treatment chamber E, and the treated water outflow portion F, and the treatment chamber D is filled with a ring-shaped hollow cylindrical particle A. To form a packed bed a, and the processing chamber E is filled with particles B such as buoyant expanded polystyrene having a smaller particle size than the hollow cylindrical particles A and having denitrifying bacteria attached to the particles. To form the filling layer b. It is extremely important to make the particles of the packed bed a floatable, and if a material that sinks in water is used, cleaning of the packed bed a becomes extremely troublesome.

With respect to the eyes of each porous water-permeable member,
The porous water-permeable member 2 is provided with a particle size smaller than that of the granules B, the porous water-permeable member 3 is provided with a particle size smaller than that of the granules A, and at least the porous water-permeable member 4 is provided. The particle size may be smaller than the particle size of the granules A, but is preferably smaller than the particle size of the granules B. With this configuration, the porous water-permeable member 3 between the precipitation section C and the processing chamber D is formed.
Can prevent the granules A from falling, and the porous water-permeable member 4 between the processing chamber D and the processing chamber E and the porous water-permeable member 2 between the processing chamber E and the outflow portion F can form the particles B. Prevents the falling and floating of the water. Moreover, the porous water-permeable member 4 can prevent mixing of the packed bed b and the granules A of the packed bed a.

In FIG. 1, in the processing chamber D partitioned by the porous water-permeable member 3 and the porous water-permeable member 4, the granules A are not filled in the space, and the granules A are not filled. Since the specific gravity is close to that of water, it is shown as being in a state of being floated up to the position of the porous water-permeable member 4 by the upward flow and / or buoyancy to form the floating filling layer a. Further, even in the processing chamber E partitioned by the porous water-permeable member 4 and the porous water-permeable member 2, the granules B are not filled in the space, and the granules B are buoyant so that the packed bed is filled. The upper surface of is in contact with the porous water-permeable member 2 to form the floating filling layer b.

Here, the cylindrical granular particles A packed in the packed bed a are hollow cylindrical granular particles A in FIG. 1, but the shape may be a hollow prismatic shape. In addition, when opening openings through which water can pass on both sides of the cylindrical granular body,
SS in sewage precipitates inside the cylinder and is easily removed, which is preferable.

The thickness of the packed bed a is preferably about 1 to 3 m, and the particle size of the granules A is 10 to 60 mm in diameter and 10 to 60 m in length.
It is preferable to use granules having a large particle size of m because the SS trapping amount can be increased. Further, the specific gravity is preferably close to 1.0 for facilitating washing, and known ones such as polypropylene can be used. The layer thickness of the filling layer b is about 1 to 1.5 m, and it is preferable that the layer thickness of the filling layer a ≧ the layer thickness of the filling layer b. The particle size of the buoyant granular material B packed in the packing layer b is preferably as small as 0.5 to 10 mm, and the specific gravity is less than 1.0 and floats in water. This is a feature of the present invention and is an essential factor for performing filter bed cleaning only with air. For example, as the material thereof, known materials such as expanded polystyrene, expanded polypropylene, polypropylene, lightweight aggregate, etc. can be used, and in particular, expanded granules having a rough surface are preferable because they can also effectively attach denitrifying bacteria. .

[0014] Filtration denitrification apparatus 1 of the present invention can handle raw sewage or the like containing wastewater containing organic SS and NO _X -N simultaneously, especially sticky the organic SS and NO _X -N simultaneously However, there is a feature. Organic SS and N in raw water
When it contains O _X -N, it is supplied from a wastewater supply device 5 equipped with a supply valve 6 at the bottom of the filtration and denitrification device of the present invention, and the raw water is placed on the packed bed a and the packed bed b in the device 1 in that order. SS and nitrogen contained in the raw water are removed as a countercurrent flow, overflow from the filter bed, flow out to the treated water outflow conduit 7, and are discharged as treated water through the treated water outflow pipe 9 to the outside of the system. It

[0015] If NO _X -N content of the raw water is small, N
O _X -N-containing water is supplied from the containing NO _X -N water supply device 8 is provided under the packed bed b of the processing chamber E, it is biologically denitrification in the packed layer b. An example of such a case is, for example, a case where a nitrification apparatus is installed subsequent to the present apparatus and the nitrification-treated water is circulated from the nitrification apparatus.

Below the water surface of the treated water outflow conduit 7, there is provided a porous water-permeable member 2 (consisting of a punching plate, a grating (grid), a net, etc.) having a pore diameter capable of preventing the outflow of the particles of the packed bed b. It is provided. An aeration member 11 having an air supply pipe 14 provided with a blower 10 for mainly cleaning the inside of the packed bed with air is provided in the settling section C below the packed bed. The diffusing member 11 is not only under the packed bed a but also the packed bed b.
It may be separately provided under the. However, a small amount of oxygen-containing gas may be diffused by the blower 10 or the diffusing member 11 during normal processing, and the filtration denitrification device of the present invention may be used as an aerobic denitrification device.

[0017]

The operation principle of the present invention will be described below. Raw water such as sewage flows from the wastewater supply device 5 into the lower part of the filter denitrification device 1 of the present invention in an upward flow, and first, in the precipitation part C at the lower part of the device 1, those having large sedimentation properties such as coarse particles are precipitated. After doing
Next, it enters into the packed bed a filled with polypropylene hollow cylindrical particles provided in the processing chamber D in an upward flow. The hollow cylindrical granules forming the packed bed a have voids inside the granules and the side surfaces are open, so that the porosity of the packed bed a can be kept extremely high at 95% or more. Therefore, even if a large amount of SS is captured by the granules A of the packed bed a, the porosity can be maintained at a large level, and therefore the increase in filtration resistance is extremely small. Thus, while the raw water passes through the packed bed a filled with the hollow cylindrical particles, the SS having a particle size of 10 μm or more in the raw water is used.
95% is removed, but fine SS having a particle size smaller than that is not removed but flows out from the packed bed a, so this fine SS is removed by filtration in the next packed bed b.

The specific gravity of the particles forming the filling layer b is 1.0.
It is important to use particles that are smaller and that float on water, such as expanded polystyrene, expanded polypropylene, and polypropylene, and that are easily adsorbed by denitrifying bacteria and that have a smaller particle size than granules A. Although the denitrifying bacteria may be attached separately, they naturally propagate on the filling filter medium while water is passed. The fine SS passing through the packed bed a has a particle size of 10 μm.
The following fine particles, but a packing layer b of a filter medium having a small particle size
Effectively captured within. This is because the pore size of the voids in the filling layer b is small, so that SS having a small particle size can be effectively removed. Moreover, since the SS having a large particle size is filtered and removed by the packed bed a in the preceding stage, the SS which has passed through the packed bed a has a small particle size, and the SS has a small particle size B.
The filling layer b filled with is not blocked, and therefore the increase in filtration resistance of the filling layer b can be significantly reduced. If the packed bed a does not exist, the packed bed b is promptly obtained.
Will be blocked.

By the above-mentioned action, SS in the raw water is highly removed, and NO _X -N is removed by the denitrifying bacteria adhering to the filter material of the packed bed b. The increase in filtration resistance of the filtration denitrification device according to the present invention is extremely small, and the limit of filtration can be known by the increase of SS in the treated water before the situation in which raw water cannot be passed due to the increase in filtration resistance. .

When such a state is reached, the packed bed a and the packed bed b are washed by the following method. That is, the supply valve 6 is closed, the supply of raw water from the waste water supply device 5 is stopped, the valve 13 of the sediment discharge device 12 is opened, the liquid in the device 1 of the present invention is drained, and the water surface is made porous. Water member 2
Lower below. The valve 13 of the sediment discharge device 12 is closed, and air bubbles are vigorously discharged from the air diffusing member 11. After a few minutes, the valve 13 is opened again, the air in the diffuser pipe 11 is vigorously discharged, and the filter medium A and the filter medium B are violently disturbed, and the entire amount of water in the tank is discharged from the discharge pipe 12 at the bottom of the tank. By the above operation, almost all of the SS trapped in the filter layers a and b is discharged from the discharge pipe 12.

As described above, the filtration denitrification apparatus of the present invention can be cleaned only by disturbing cleaning with air and does not require backwashing that consumes a large amount of clarified water, which is extremely rational. The reason why such a rational cleaning is possible is that the granular particles A are cylindrical and have a large particle size. This is because the SS that has been used is easily discharged together. Further, since the particles B float on the water, the particles of the particles B move violently when the air is stirred, and the particles of the particles B also move violently, causing the SS trapped in the particles B to drain. This is because it is discharged out of the system together with water. At this time, since the processing chamber D and the processing chamber E are not filled with the particles A and the particles B to fill the space, the particles are sufficiently disturbed by the air.

[0022]

EXAMPLES Below, using the filtration denitrification apparatus of the present invention,
It shows a specific embodiment for removing the SS and NO _X -N raw water. However, the embodiments of the present invention are not limited to the following description.

(Example 1) Average content of SS is 200 mg
Sewage containing high SS, which is 1 liter / liter, is used as raw water, and the sewage is supplied from the sewage supply device 5 in the space 2 of the filtration denitrification device having the following specifications into the device in an upward flow and NO ₃ N3
NO _x -N water supply device 8 containing a liquid containing 0 mg / liter
Supply twice the amount of raw water (from the wastewater supply device 5)
The effect of the present invention was verified. Table 1 shows the device specifications.

[0024]     Table 1 (Processing conditions)       Filtration and denitrification equipment:         Height of space D: 2.5m         Height of space E: 1.5m         Height of packed bed a: 2.0 m         Height of packed bed b: 1.0 m       Porous water-permeable member 3: 20 mm opening width screen       Porous water-passing members 4 and 2: 0.8 mm opening width screen         Granule A: Diameter 20 mmφ, length 30 mm cylinder                                   Made of polypropylene         Granule B: Particle diameter 1 mm                                   Made of expanded polystyrene

Table 2 shows processing conditions and processing results. Table 2 (Treatment conditions) Water flow rate: 50 m / day (packed bed a part), 150 m / day (packed bed b part) (Treatment result) Treated water NO ₃ -N content: 1.2 mg / liter Treated water SS Content: 5.5 mg / liter NO ₃ -N removal rate: 96% SS removal rate: 97.2% Treatment duration ^** : 48 to 52 hours ** Here, treatment duration is included in treated water It refers to the time until the amount of SS reaches 10 mg / liter.

The average SS trapping capacities of the packed bed a and the packed bed b were about 15 kg SS / (m ³ filter medium). Comparing this with the case of conventional filtration using anthracite (particle size 3 mm), the average SS trapping capacity is 2 kgSS / (m
³ filter media), and when these results are compared, the prominence of the filtration device of the present invention is clear.

[0027]

EFFECTS OF THE INVENTION 1) A filtration denitrification method in which the increase in filtration resistance is extremely small, the effect of removing SS is extremely high, and the filter denitrification treatment can be carried out efficiently. 2) clogging significantly less, a high filtration denitrogenation apparatus of denitrification efficiency. 3) The packed bed can be effectively washed, and since it is not necessary to use treated water as washing water, the treated water production efficiency is high. 4) The treatment duration is long and the filtration rate is high. Therefore, only a compact device is required and maintenance is easy.

[Brief description of drawings]

FIG. 1 is a flow diagram illustrating a flow of a treatment method of the present invention using an example of a filtration denitrification apparatus of the present invention.

[Explanation of symbols]

1 Filtration denitrification device 2 porous water passage member 3 porous water passage member 4 porous water passage member 5 sewage feed devices 6 supply valve 7 treated water outlet sewer 8 including NO _X -N water supply device 9 the treated water outlet pipe 10 Blower 11 Diffuser 12 Precipitate Discharge Device 13 Valve 14 Air Supply Pipe a Lower Packed Bed b Upper Packed Bed A Granules B Granules C Settling Section D Treatment Room E Treatment Room F Treated Water Outflow Section

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-113399 (JP, A) JP-A-5-253583 (JP, A) JP-A-4-66193 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C02F 3/28-3/40

Claims (2)

(57) [Claims] 1. A processing chamber is formed in upper and lower stages by partitioning the inside of a tank with a porous member, and further, a lower part than the lowermost porous member is a precipitation part, and an upper part is a treated water outflow part. The settling section is provided with a sewage supply device and a cleaning gas supply device, and a sediment discharge device at the bottom of the tank, and at least the lower processing chamber has hollow cylindrical particles with a specific gravity close to that of water. and SS filtration layer provided in the floating filler layer, to form a space thereunder, the upper processing chamber, wherein less than hollow cylindrical granules, and the floating filler layer of the floating of the granules is provided in the water
Te and denitrification layer, forming a space thereunder, sewage filtration denitrification, characterized in that a containing NO _X -N water supply device for supplying water containing NO _X -N in the space portion apparatus. 2. A method of performing filtration and denitrification by contacting sewage with granules on which microorganisms are immobilized, the sewage being flown upward into a floating packed bed of hollow cylindrical granules having a specific gravity close to that of water.
After flowing to filter SS, set it on the upper stage of the floating packed bed.
The NO _x -N is introduced into the floating packed bed of granular particles which are smaller than the hollow cylindrical granular particles and floatable in water in an upward flow to introduce nitrogen into the nitrogen.
While reducing the gas, NO _X -N in the upper floating packed bed of
Filtration denitrification how sewage which comprises treating while supplying water containing.