JPH0818031B2 - Sewage purification filter material and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a filter medium used in a submerged filter method, which is one of sewage purification methods, and a manufacturing method thereof.

[Problems to be Solved by Conventional Techniques and Inventions] In the immersion filter method, sewage is passed through a filter bed filled with a filter medium (hereinafter, referred to as a biochemical treatment tank), and sewage It is a method of decomposing and purifying the organic substances of. There are various types of filter media, and the following are conventional filter media related to the present invention.

(1) As shown in FIG. 8, it is a granular body (for example, pebbles) having a diameter of 20 to 40 mm, which is made of calcium silicate hydrate having many fine pores, and is filled in the biochemical treatment tank 12 in a loose state. Filter medium 21 This filter medium 21 has a small diameter and a large number of filling particles (for example, the number of filling particles having a diameter of 20 mm is about 150,000 pieces / m ³ ), so that the total surface area becomes large and the purification efficiency of the wastewater W is increased. it was high. In addition, the presence of many micropores of appropriate size (500-1000 μm in diameter), pH buffering capacity of calcium silicate hydrate,
The property such as the elution of a small amount of SiO ₂ also has an effect of creating a suitable habitat environment for microorganisms to enhance the function of the microorganisms, and calcium silicate hydrate adsorbing phosphorus in the wastewater W by a crystallization reaction. .

On the other hand, since the filter medium 21 has a small diameter and thus has a large total area of contact with each other, there is a problem that when the filter media 21 are moved by the air during aeration and collide with each other, they are rapidly worn. In addition, since the diameter is also small, the filter media 21
Since the gap between them is also small, the sludge solids (SS) in the wastewater and the wear of the granules themselves are immediately clogged in this gap, which reduces the air permeability at the time of aeration and approaches the anaerobic state, There was also a problem that the chemical treatment tank 12 was clogged.

(2) As shown in FIG. 9, it is a granular material made of calcium silicate hydrate having many fine pores and having a diameter of 20 to 40 mm, which is biochemically packed in a net bag 22 of an appropriate size. The filter medium 21 filled in the processing tank 12 has the same advantages and disadvantages as those of the filter medium, and since the mesh bag 22 restrains the movement of the filter medium 21, the filter medium 21 particularly in the center portion of the mesh bag 22. There was a problem that it was easy for each other to get stuck.

(3) Raschig ring (not shown) formed in a cylindrical shape from unglazed, porcelain, synthetic resin, etc. This filter medium does not have the above-mentioned problem of wear, but it has an appropriate size such as calcium silicate hydrate. Since it does not have micropores (the micropores on the bisque-fired surface are orders of magnitude smaller), it is not possible to create a suitable microbial habitat environment as high as the calcium silicate hydrate, which is not sufficient in terms of purification efficiency. Further, it is difficult to remove phosphorus in wastewater because a crystallization reaction with phosphorus such as calcium silicate hydrate cannot be expected.

The object of the present invention is to solve the above-mentioned problems, to improve the purification efficiency of sewage by the microorganism by creating a suitable living environment for the microorganism, and to adsorb phosphorus in the sewage, and the filter medium The provided through-holes or grooves increase the total surface area to ensure high purification efficiency, reduce the total area where the filter media contact with each other to reduce the amount of wear during aeration, and increase the space between the filter media and within the filter media. A new sewage purification filter that creates gaps to prevent clogging of sludge solids in sewage and wear of the filter itself, as well as ensuring air permeability during aeration and maintaining high purification efficiency for a long time. It is to provide a novel manufacturing method capable of easily manufacturing this filter medium with simple equipment.

[Means for Solving the Problems] In order to achieve the above object, the filter medium for purifying wastewater according to claim 1 is made of calcium silicate hydrate having many fine pores, and has X-axis, Y-axis and Z-axis. The total length in each direction is 20
It is a lump in the range of 0 to 400 mm and has a cross-sectional area of 30
A through hole having a diameter of 0 mm ² or more or a groove having a cross-sectional area in the groove of 100 mm ² or more is provided.

Further, the method for producing the filter medium for purifying sewage according to claim 2,
The step of forming a semi-hardened plate-like body from the raw material slurry of calcium silicate hydrate, and the aggregate length in the X-axis, Y-axis, and Z-axis directions is in the range of 200 to 400 mm. The cross-sectional area of a through hole or groove with a cross-sectional area of 300 mm ² or more.
A structure including a step of punching a sheet having a groove of 0 mm ² or more from the plate and a step of curing the block at high pressure and high temperature steam was adopted.

Further, the method for producing a filter medium for purifying sewage according to claim 3 is
By injecting the raw material slurry of calcium silicate hydrate into the cavity of the mold, a lump having a total length in the X-axis, Y-axis and Z-axis directions in the range of 200 to 400 mm, A through hole or groove with an internal cross-sectional area of 300 mm ² or more has an internal cross-sectional area of 10
The configuration includes a step of molding a material having a groove of 0 mm2 or more and a step of curing the lump at high pressure and high temperature.

In the above, a concrete shape of the "lump" may be a cylinder, a prism, a sphere, or the like. Also, "X
"Axis, Y-axis and Z-axis" are three-dimensional coordinate axes that are orthogonal to each other, and which direction of the lump is the X-axis and the Y-axis and the Z-axis can be arbitrarily determined. The "length in each direction of the X-axis, Y-axis, and Z-axis" is measured by applying parallel rays from a light source to a lump, and observing the lump on the projection wall provided in the direction opposite to the light source. A method (projection method) of photographing a shadow of a body and measuring the length of the largest part of the shadow can be exemplified. In addition, "the lump in which the total length in each direction of the X axis, Y axis, and Z axis is in the range of 200 to 400 mm" is 20
If it is less than 0 mm, problems such as wear and clogging as in the conventional example will occur, and if it exceeds 400 mm, the number of filling and the total surface area when the filter medium is filled in the biochemical treatment tank are reduced and purification is performed. This is because the efficiency is reduced.

Next, as a "through hole", one that penetrates through the cylinder or prism in the axial direction (hence the agglomerate becomes a cylinder or prism),
Examples thereof include one that penetrates in the direction orthogonal to the axial direction, one that penetrates the sphere in three directions orthogonal to each other, and the like. Further, as the “groove portion”, a groove portion having an arcuate cross section, U-shape, V-shape or rectangular shape formed in parallel to the axial direction or in the circumferential direction with respect to the side wall of the column or prism can be exemplified. . Further, "a through hole having an inner cross-sectional area of 300 mm ² or more" or "a groove portion having an inner groove cross-sectional area of 100 mm ² or more" means that when each cross-sectional area is less than those, the clogging of the through hole or the groove portion This is because problems will arise. A more preferable cross sectional area in the hole is 700 mm ² or more, and a more preferable cross sectional area in the groove is 200 mm ² or more.

[Operation] The sewage purification filter according to claim 1 is suitable for microorganisms due to the properties such as the presence of many micropores of appropriate size, the pH buffering ability of calcium silicate hydrate, and the elution of a trace amount of SiO _2. Not only can it create a habitat environment to improve the purification efficiency of sewage by the microorganisms, or can adsorb the phosphorus by a crystallization reaction between calcium silicate hydrate and phosphorus in the sewage, the following effects Play.

Since the size of each part of this filter medium is larger than that of the conventional granular body of calcium silicate hydrate, the number of filling is reduced. Therefore, the total area of contact with each other becomes small, and even if the filter media move due to the air flow during aeration, the area ratio of collision with each other becomes low, and the amount of wear decreases.

Since this filter medium has a large size as described above, a large gap is created between the filter mediums, and the presence of the through hole or the groove portion further increases the gap. Therefore, sludge solids in the wastewater and the wear of the filter medium itself are less likely to be clogged, the air permeability during aeration is maintained, and the biochemical treatment tank is less likely to be blocked.

By the way, if the size of each part of the filter medium is simply increased, the total surface area is reduced and the purification efficiency is reduced. However, since this filter medium has a large surface area due to the through holes or the groove portions, it is possible to secure a high purification efficiency.

Further, according to the method for producing a filter medium for purifying sewage according to the second or third aspect, it is possible to easily produce a filter medium capable of exhibiting the above-mentioned action with simple equipment.

[Examples] Hereinafter, a first example of the filter medium for purifying sewage embodying the present invention will be described with reference to FIGS. 1 to 5.

The filter medium 1 of this example has a diameter of 500 to 1000 on the surface and inside.
It is a lump made of calcium silicate hydrate having many micropores 3 of μm, and is a short cylindrical shape in which the through holes 2 are formed in the axial direction. The dimensions of each part of the filter medium 1 are preferably in the following ranges ad.

a; Outer diameter (corresponding to the length in the X-axis and Y-axis directions) is 50 to 200 mm
And more preferably 70 to 140 mm.

b; The height (corresponding to the length in the Z-axis direction) is 50 to 200 m, more preferably 70 to 140 mm.

c; The inner diameter of the through hole 2 is 20-100 mm (hole cross-sectional area: 314-7850 m
m ² ), more preferably 30 to 80 mm (hole cross-sectional area; 7
06 ~ 5024mm ² ).

d; The ratio of the inner diameter to the outer diameter is 0.3 to 0.6.

The dimensions that are most balanced in terms of the effect and ease of handling described later are the outer diameter of about 100 to 120 mm and the height of about 100 to 120 m.
m, the inner diameter of the through hole is considered to be about 40-60 mm.

Examples of the calcium silicate hydrate include porous artificial minerals obtained by mixing, hardening and curing at high pressure and high temperature steam with a siliceous raw material such as silica and a calcium oxide raw material such as lime cement. . Specific components include those containing, as a main component, one or more selected from the group consisting of tobermorite, xonotlite, C—S—H gel, foshagitite, gyrolite, and hileptandite. The composition ratio of the SiO ₂ content and the CaO content and the presence / absence and type of other trace components are not limited.
Further, the porosity of the calcium silicate hydrate due to the fine pores 3 is suitably 50 to 90%, preferably 60 to 90%.
This is because when the porosity is less than 50%, the immobilization of microorganisms is poor, and when it exceeds 90%, floating occurs. In this example, a porous calcium silicate hydrate containing tobermorite as a main component and having a porosity of about 75% was used.

As described above, the reason why the porous calcium silicate hydrate is used as the material for the filter medium 1 is as follows.

Due to the excellent ability of supporting microorganisms due to the large number of micropores, the density of microorganisms increases and the variety of species also increases. Also,
Backflushing does not remove all the microorganisms.

Phosphorus in wastewater can be removed at an extremely high removal rate by the crystallization reaction of calcium silicate hydrate with calcium.

Sewage becomes weakly acidic as nitrification of ammonia progresses and nitrification is suppressed, but calcium silicate hydrate has a pH buffering action to keep pH weakly alkaline, so the digestion is promoted and the removal rate of nitrogen is also increased. Get higher

The filter medium 1 can be manufactured by various methods, and according to the following two kinds of methods, both can be easily manufactured by simple equipment.

(1) As shown in FIG. 2, a semi-hardened plate-like body 4 is formed from a raw material slurry obtained by mixing a siliceous raw material such as silica stone with a calcium oxide raw material such as quick lime and cement.
From this semi-cured plate-like body 4, a plurality of uncured filter media 1a
A method for producing the filter medium 1 by punching and forming, and curing the filter medium 1a with high pressure and high temperature steam.

(2) As shown in FIGS. 3 and 4, the raw material slurry is injected into a plurality of bottomed cylindrical cavities 6 provided in the mold 5 to form a plurality of uncured filter media 1a. And the filter medium
A method for producing the above-mentioned filter medium 1 by demolding 1a and then curing it under high pressure and high temperature steam. The frame 5 includes a lower plate 9 having a plurality of convex portions 7 for forming the inner diameter of the filter medium 1 and a convex wall 8 for mold matching, and a plurality of molding holes for forming the outer diameter of the filter medium 1.
It is a simple one composed of an upper plate 11 provided with 10, and the projection 8 and the molding hole 10 are provided with a tapered draft.

Now, the filter medium 1 configured as described above is, for example, the fifth
It is filled in the biochemical treatment tank 12 as shown in the figure. At this time, since the filter medium 1 is larger in size than the conventional calcium silicate hydrate granules and has the through holes 2,
Large gaps are created between the filter media 1 and within the filter media 1, and the total area of contact with each other is also reduced.

The biochemical treatment tank 12 is provided with a transfer inflow pipe 13 for introducing the wastewater W into the bottom portion thereof, so that the wastewater W flows through the biochemical treatment tank 12 from the bottom to the top. An air diffuser 14 is provided at the bottom of the biochemical treatment tank 12 so that air sent from a blower (not shown) is blown out for aeration. The biochemical treatment tank 12 is generally provided with a plurality of tanks in series, but there may be a case where only one tank is provided.

Although not shown, before the biochemical treatment tank 12 as seen from the flow of sewage, a sewage storage tank that stores sewage, an adjustment tank that absorbs changes in the water level, a mixture that mixes sewage and purified water. A tank or the like is provided as needed. Further, after the biochemical treatment tank 12, a purified water storage tank for storing purified water treated in the biochemical treatment tank, a disinfection tank for disinfecting and sterilizing the purified water, a biochemical treatment tank or a wastewater storage tank. A sludge tank for draining and storing sludge accumulated at the bottom is provided as necessary.

As described above, according to the filter medium 1 of the present example filled in the biochemical treatment tank 12, the presence of many micropores 3 having an appropriate size, the pH buffering ability of calcium silicate hydrate, the trace amount of SiO ₂ It is possible to create a suitable habitat environment for microorganisms by properties such as elution to improve the purification efficiency of wastewater by the microorganisms, or to adsorb the phosphorus by a crystallization reaction between calcium silicate hydrate and phosphorus in the wastewater. Instead, the following actions and effects are exhibited.

Since the filter medium 1 has a larger size in each part than the conventional calcium silicate hydrate granules, the number of fillings decreases. For example, the number of filled filter media 1 having an outer diameter of 100 mm and a height of 100 mm is about 1000 / m ³ , and the filter media 1 having an outer diameter of 120 mm and a height of 100 mm is 1
The filling number of is about 800 / m ³ . Therefore, as described above, the total area in contact with each other is also small, and even if the filter medium 1 moves due to the air flow during aeration, the area ratio where the filter media 1 collide with each other becomes low, and the amount of wear decreases.

In addition, as described above, since a large gap is created between the filter media 1 and in the filter media 1, the sludge solids in the wastewater and the wear of the filter media 1 themselves are less likely to be clogged, and the air permeability at the time of aeration is maintained. The processing tank is difficult to block.

By the way, if the size of each part of the filter medium 1 is simply increased, the total surface area is reduced and the purification efficiency is reduced.
However, since the filter medium 1 of the present embodiment has a large surface area due to the through holes 2, a high purification efficiency can be secured.

Next, the filter medium 1 of the second embodiment shown in FIG. 6 differs from the first embodiment only in that it is a sphere having through holes 2 formed in three directions orthogonal to each other. The dimensions of each part of the filter medium 1 are preferably in the following ranges ac.

a; Outer diameter (corresponding to the length in the X-axis, Y-axis and Z-axis directions) is 50-
It is 200 mm, more preferably 70 to 140 mm.

b; The inner diameter of the through hole 2 is 20-100 mm (hole cross-sectional area: 314-7850 m
m ² ), more preferably 30 to 80 mm (hole cross-sectional area; 7
06 ~ 5024mm ² ).

c; The ratio of the inner diameter to the outer diameter is 0.3 to 0.6.

It is considered that the most balanced dimension in terms of effectiveness and ease of handling is an outer diameter of about 100 to 120 mm and an inner diameter of the through hole of about 40 to 60 mm.

Next, the filter medium 1 of the third embodiment shown in FIG. 7 is different from the first embodiment only in that it is a prismatic body in which four groove portions 15 having a four-quarter arc shape in cross section are formed on the side wall. The filter medium 1
Is manufactured by dividing the remaining portion after punching out the uncured filter medium 1a from the plate-like body 4 in the structural method (2) of the first embodiment shown in FIG. It is something. The dimensions of each part of the filter medium 1 are in the following range a-
Preferably it is in c.

a; Width and depth (corresponding to the length in the X-axis, Y-axis, and Z-axis directions)
Is 50 to 200 mm, more preferably 70 to 140 mm.

b; The radius of the groove 15 is 20 to 100 mm (hole cross-sectional area: 114 to 2850 m
m ² ), more preferably 35 to 70 mm (hole cross-sectional area: 3
49 to 1397 mm ² ).

c; The width of the portion remaining between the groove portions 15 is 10 to 30 mm.

The most balanced dimensions in terms of effectiveness and ease of handling are width and depth of about 120140 mm, and the radius of the groove 15 of about 50-60.
It is considered to be about mm.

These second and third embodiments also have the same actions and effects as the first embodiment.

The present invention is not limited to the configurations of the above-described embodiments, and can be embodied by being arbitrarily modified without departing from the spirit of the invention.

[Effects of the Invention] Since the present invention is configured as described above, it has the following excellent effects.

According to the filter medium for sewage purification according to claim 1, the normal effect of calcium silicate hydrate having many micropores (that is, creating a living environment suitable for microorganisms to improve the efficiency of sewage purification by the microorganisms) The following effects a to d can be obtained as well as the effect of adsorbing phosphorus in wastewater).

a: Compared with the conventional calcium silicate hydrate granules, the size is remarkably large, so the number of filling is reduced, and therefore the manufacturing cost can be reduced.

b: The total area where the filter media contact each other is small, and the amount of wear during aeration can be reduced.

c: Prevents clogging of sludge solids in sewage and wear of the filter itself by creating large gaps between the filter media and within the filter media, while ensuring air permeability during aeration, thus maintaining high purification efficiency for a long time. be able to.

d: Through holes or grooves provided in the filter medium make it possible to secure a high purification efficiency by increasing the total surface area.

Further, according to the method for producing a filter medium for purifying sewage according to claim 2 or 3, it is possible to easily produce a filter medium capable of exhibiting the above effects with simple equipment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a filter medium according to a first embodiment of the present invention, and FIG.
FIG. 1 is a perspective view showing a first method for manufacturing the filter medium, FIGS. 3 and 4 are perspective views showing a second method for manufacturing the filter medium, and FIG. 5 is a biochemical treatment tank filled with the filter medium. Sectional view shown, No. 6
FIG. 7 is a front view showing the filter medium of the second embodiment, and FIG. 7 is a perspective view showing the filter medium of the third embodiment. FIG. 8 is a sectional view showing a conventional biochemical treatment tank filled with a filter medium, and FIG. 9 is a sectional view showing a conventional biochemical treatment tank filled with another filter medium. 1 ... filter material, 2 ... through hole, 3 ... fine hole, 4 ... plate-like body,
5 ... Formwork, 6 ... Cavity, 12 ... Biochemical treatment tank, 15 ... Groove.

Claims (3)

[Claims] 1. A lump comprising a calcium silicate hydrate having a large number of micropores (3) and having a total length in each direction of the X-axis, Y-axis and Z-axis in the range of 200 to 400 mm. Through hole (2) with a hole cross-sectional area of 300 mm ² or more, or a groove cross-sectional area of 100 mm ²
A filter medium for purifying sewage, which has the above groove (15). 2. A step of forming a plate-like body (4) in a semi-cured state from a raw material slurry of calcium silicate hydrate, X axis, Y
A lump having a total length in each direction of the Z-axis and the Z-axis in the range of 200 to 400 mm, the through-hole (2) having an in-hole cross-sectional area of 300 mm ² or more or the in-groove cross-sectional area of 100 mm ² or more A method for producing a sewage purification filter medium, which comprises a step of punching a product having a groove (15) from the plate-like body (4) and a step of curing the lump at high pressure and high temperature steam. 3. X is obtained by injecting a raw material slurry of calcium silicate hydrate into the cavity (6) of the form (5).
A lump that has a total length in each direction of the axis, Y-axis, and Z-axis within the range of 200 to 400 mm, and has a through-hole (2) with a hole cross-sectional area of 300 mm ² or more or a groove internal cross-sectional area of 100 mm. ^A method for producing a sewage purification filter medium, which comprises a step of molding a material having ^two or more groove parts (15) and a step of curing the lump at high pressure and high temperature steam.