JP2002177990A - Water cleaning method and water cleaning plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide water cleaning method and water cleaning plant for public water supply which can be relatively downsized in facilitates, necessitate relatively narrow floor spaces and are capable of adequately removing algae and suspended solids of small grain sizes. SOLUTION: The upper part of a septic water tank 20 is compartmentalized to an ozone reaction region 20A and the lower part to a granular activated carbon living body filtration region 20B. The upper part of the ozone reaction region 20A is provided with a raw water nozzle 21 and the lower part with a dissolved ozone water nozzle 22. The granular activated carbon 23 having biofilms is packed into the granular activated carbon living body filtration region 20B. The water dissolved with ozone and air is pressurized and is introduced from the water dissolved with ozone nozzle 22 to form an air bubble zone Z and the raw water subjected to flocculation treatment is introduced from the raw water nozzle 21 and is passed through the air bubble zone Z by downward current and thereafter the water is passed through the granular activated carbon living body filtration region 20B. Accordingly, the undissolved materials and dissolved materials can be removed by the one septic water tank and therefore the facilities are downsized. Since floc (f) is floated and separated, the algae and the suspended solids of small grain sizes are effectively removed as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purification method and a water purification apparatus, and more particularly, to a relatively small-sized facility and a relatively small installation space, and it is also suitable for algae and suspended substances having a small particle size. The present invention relates to a water purification method and a water purification device that can be removed.

[0002]

2. Description of the Related Art Conventionally, in the case of producing tap water by purifying raw water such as river water and lake water, undissolved substances (solid components such as turbidity and algae) contained in the raw water are converted into a coagulant by the raw water. Into floc, which was removed by precipitation and filtration. The dissolved substances (chromatic components, colloidal substances, organic substances, etc.) contained in the raw water are as follows:
Ozone was injected into the raw water and oxidatively decomposed and removed.

[0003]

In the conventional water purification method described above, in order to stably precipitate flocs in removing insoluble substances, a sedimentation basin having a water depth of 3 to 4 m is required and the sedimentation basin is required. A sludge discharging facility is also required at the bottom, and an ozone reaction tank having a water depth of 4 to 6 m is required in order to bring ozone and raw water into sufficient contact in removing dissolved substances. That is, a large sedimentation basin and a large ozone reaction tank are required, and there is a problem that the equipment becomes large and a large installation space is required. Further, in removing insoluble substances, there is a problem that algae and suspended substances having a small particle size do not settle even if flocculated, and are difficult to remove. Therefore, an object of the present invention is to provide a water purification method and a water purification apparatus for a water supply system, which can make the equipment relatively small and require a relatively small installation space, and can also preferably remove algae and suspended substances having a small particle diameter. is there.

[0004]

According to a first aspect of the present invention, an upper part of a purified water tank is divided into an ozone reaction area and a lower part is divided into a granular activated carbon biological filtration area, and a raw water introduction part is provided above the ozone reaction area. Provided, an ozone dissolved water introduction unit is provided below the ozone reaction region, the granular activated carbon biological filtration region is filled with granular activated carbon, and the dissolved water of ozone and air is pressurized and introduced into the ozone dissolved water introduction unit. A bubble zone is formed above the ozone-dissolved water introduction unit, and the raw water subjected to the coagulation treatment is introduced into the raw water introduction unit, passed through the bubble zone in a downward flow, and then passed through the granular activated carbon biological filtration region. A water purification method is provided. In the water purification method according to the first aspect, since the coagulated raw water passes through the bubble zone in a downward flow, the bubbles adhere to the surface of the floc at that time, and the floc floats due to the buoyancy of the bubbles, thereby causing an imperfection. Dissolved substances can be separated. Also, when the raw water passes through the bubble zone, it comes into contact with ozone, so that the dissolved substance is oxidized and decomposed, or becomes insoluble and floats together with the bubbles to be removed. Unfloated flocs and solids can be removed in the granular activated carbon biofiltration zone. Further, since the dissolved substance that could not be oxidized and decomposed is reduced in molecular weight, it is adsorbed and removed in the granular activated carbon biofiltration region or decomposed in the biofilm. As described above, since the insoluble substance and the dissolved substance can be simultaneously removed by one purifying water tank, the equipment can be made relatively small and the installation space can be made relatively small. Furthermore, in order to float and separate the flock,
Algae and suspended substances having a small particle size can be particularly effectively removed.

Since the conventional ozone reaction tank is supplied with air containing ozone through a diffuser, the bubble size is relatively large and the number of bubbles is relatively small. For this reason,
The gas-liquid contact area is small as a whole, and an ozone reaction tank having a water depth of 4 to 6 m is required in order to bring ozone and raw water into sufficient contact. On the other hand, in the water purification method according to the first aspect, dissolved water of ozone and air is pressurized and supplied to a purified water tank, and bubbles are generated by being depressurized in the bubble zone. Small and relatively large number of bubbles. For this reason, the gas-liquid contact area becomes large as a whole, and the ozone reaction region becomes sufficient even at a water depth of about 2 m.

[0006] In a second aspect, the present invention provides a method according to the present invention, wherein the upper portion is divided into an ozone reaction region and the lower portion is divided into a granular activated carbon biological filtration region,
A raw water introduction unit is provided at an upper portion of the ozone reaction region, an ozone dissolved water introduction unit is provided at a lower portion of the ozone reaction region, and the granular activated carbon biological filtration region is a purified water tank filled with granular activated carbon, and ozone. It is provided with an ozone dissolved water pressurizing and introducing means for pressurizing dissolved water of air and introducing the ozone dissolved water into the ozone dissolved water introducing section, and a raw water introducing means for introducing coagulated raw water into the raw water introducing section. Provided is a water purification device characterized by the above. In the water purification device according to the second aspect, the water purification method according to the first aspect can be suitably implemented.

According to a third aspect of the present invention, in the water purifier having the above structure, the ozone-dissolved water pressurizing and introducing means sucks and pressurizes a part of the treated water that has passed through the granular activated carbon biological filtration area. A purifying apparatus comprising: a rotary vane pump for discharging the ozone-dissolved water introduction part; and an ozone-containing air injecting unit for injecting air containing ozone into a suction side of the rotary vane pump. I will provide a. It is possible to make pressurized water with a liquid pump, store this in a tank, pressurize air containing ozone to a pressure higher than the pressurized water with a compressor and introduce it into the tank, and make ozone-dissolved water. , A liquid pump and a compressor are required, and the equipment becomes large. On the contrary,
In the water purification device according to the third aspect, only a rotary blade pump is required, and the equipment can be simplified.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited by this.

FIG. 1 is a structural explanatory view showing an embodiment of the water purification apparatus of the present invention. The water purifier 100 includes a purified water tank 20 for purifying raw water, a treated water tank 30 for storing treated water after the purified water treatment, and a part of the treated water sucked from the treated water tank 30 to be pressurized and supplied to the purified water tank 20. A rotary vane pump 40 for discharging, an ozone-containing air generator 41 for generating air containing ozone and injecting it into the suction side of the rotary vane pump, and an exhaust ozone treatment for decomposing so that ozone gas does not leak outside. An apparatus 50 and a backwash pump 60 for backwashing the purified water tank 20 are provided. The raw water is obtained by adding and stirring a flocculant to river water or the like in the flocculation treatment apparatus A.

The purified water tank 20 has an ozone reaction region 20A in the upper part 2m and a granular activated carbon biological filtration region 20 in the lower part 2m.
B. Above the ozone reaction region 20A, a raw water nozzle 21 for introducing raw water obtained by adding a coagulant to river water, lake water, or the like is provided. An ozone dissolved water nozzle 22 for introducing ozone dissolved water obtained by pressurizing dissolved water of ozone and air is provided below the ozone reaction region 20A. The granular activated carbon biological filtration area 20B is filled with granular activated carbon 23.

A scum discharge port 24 is opened on a wall surface of the purified water tank 20 above the raw water nozzle 21. The scum discharge port 24 communicates with a scum drain pipe 25. A backwash water drainage trough 26 is provided slightly above the upper surface of the granular activated carbon 23 of the purified water tank 20. The backwash water drain trough 26 communicates with a backwash water drain pipe 27. In addition, the purified water tank 20
A water collecting chamber 29 communicating with the granular activated carbon biological filtration area 20B by a water collecting nozzle 28 is provided at the bottom of the water collecting nozzle 28.

FIG. 2 is an explanatory diagram showing a state at the time of the water purification treatment. During the water purification process, the backflow drain pipe 27 is kept closed. When raw water is introduced from the raw water nozzle 21, the raw water flows down in the purified water tank 20 in a downward flow.

When the rotary vane pump 40 is driven while generating ozone-containing air having an ozone concentration of 2 to 3 wt% from the ozone-containing air generator 41, the pressurized ozone-dissolved water flows from the ozone-dissolved water nozzle 22 into raw water. Although spouting occurs, the pressure drops rapidly, so that many fine bubbles b are generated, and a bubble zone Z is formed above the ozone-dissolved water nozzle 22.

A bubble b adheres to the floc f in which the insoluble substance is aggregated by the flocculant in the bubble zone Z. For this reason, the flock f floats by the buoyancy of the bubble b, and becomes the scum s. The scum s flows out from the scum drain port 24 to the scum drain pipe 25 by surface flow, and is discharged. The scum s may be collected using a scum skimmer, a screver, injection water, or the like, and discharged from the scum drain port 24 to the scum drain pipe 25.

On the other hand, the dissolved substance in the raw water is in the bubble zone Z
, It is oxidatively decomposed or becomes insoluble and floats with the bubbles b to be discharged as scum s. For example, dissolved substances such as iron and manganese are oxidized by the ozone-containing air and become insoluble, air bubbles b adhere and float, and are discharged as scum s.

The ozone-containing air coming out of the surface of the raw water is detoxified by the waste ozone treatment device 50 and then released into the atmosphere.

The raw water passes through the granular activated carbon biofiltration zone 20B at a filtration speed of 200 to 400 m / day. When the granular activated carbon biological filtration area 20B is 2 m, the residence time is 4 to
7 minutes. At this time, heavy flock f that did not surface
Is adsorbed on the granular activated carbon 23. In addition, dissolved substances that could not be oxidatively decomposed are adsorbed on the granular activated carbon 23,
It is decomposed by the biofilm that propagates on the granular activated carbon 23. In addition,
The biofilm uses the organic matter adsorbed on the granular activated carbon 23 as a nutrient source and utilizes ozone and oxygen in raw water to form the granular activated carbon 2.
Propagate to 3.

As described above, the insoluble substance and the dissolved substance can be simultaneously removed in one purified water tank 20, so that the equipment can be made relatively small and a relatively small installation space is required. Furthermore, since the floc f is floated and separated, even algae and suspended substances having a small particle diameter can be effectively removed.

In addition, the ozone-dissolved water is, for example,
It may be produced using a gas-liquid mixing and dissolving apparatus disclosed in Japanese Patent Application Laid-Open No. 0-161278. Alternatively, ozone-dissolved water may be generated by extracting the treated water from the water collecting chamber 29, dissolving the ozone-containing air and pressurizing the ozone-containing air. Alternatively, ozone-dissolved water may be generated by extracting raw water, dissolving ozone-containing air, and applying pressure.

FIG. 3 is an explanatory view showing a state at the time of back washing. First, the flow of raw water is stopped, and the purified water tank 20 is emptied. Next, the backflow drain pipe 27 is opened. Next, the reverse flow pump 60 is operated, and the treated water in the treated water tank 30 is
The water is supplied to the water collecting chamber 29 of the purified water tank 20. Then, the treated water passes through the water collecting nozzle 28 and the granular activated carbon biological filtration area 20
B penetrates, rises to the backwash drain trough 26, and is discharged from the backwash drain trough 26 to the backwash drain pipe 27. As a result, the granular activated carbon 23 is backwashed and clogging is eliminated, and the processing capacity is restored.

[0021]

According to the water purifying method and the water purifying apparatus of the present invention, the insoluble substance and the dissolved substance can be removed simultaneously in one purifying water tank, so that the equipment can be made relatively small and the installation space is relatively small. In addition, algae and suspended substances having a small particle size can be suitably removed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a water purification device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state of a water purification apparatus according to an embodiment of the present invention during a water purification process.

FIG. 3 is an explanatory view showing a state at the time of backwashing of the water purification device according to the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 water purification device 20 purified water tank 20A ozone reaction area 20B granular activated carbon biological filtration area 21 raw water nozzle 22 ozone dissolved water nozzle 23 granular activated carbon 24 scum drain outlet 25 scum drain pipe 30 treatment water tank 40 rotary vane pump 41 ozone-containing air generator A Coagulation treatment equipment

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C02F 9/00 503 C02F 9/00 503A B01F 1/00 B01F 1/00 A C02F 1/24 C02F 1/24 B 1/78 ZAB 1/78 ZAB 3/10 3/10 A F-term (Reference) 4D003 AA01 AB12 BA02 CA02 CA07 DA07 DA14 DA15 DA22 EA01 EA25 4D037 AA01 AB02 BA02 BA04 BB05 CA07 CA08 CA11 4D050 AA03 AB07 BB02 BD03 BD06 CA04 4G035 AA01 AE13

Claims (3)

[Claims] 1. An ozone reaction region is defined at an upper portion of a purified water tank, and a granular activated carbon biological filtration region is defined at a lower portion. A raw water introduction portion is provided at an upper portion of the ozone reaction region, and an ozone dissolved water introduction portion is provided at a lower portion of the ozone reaction region. The granular activated carbon biological filtration area is filled with granular activated carbon, and dissolved water of ozone and air is pressurized and introduced into the ozone dissolved water introduction section to form a bubble zone above the ozone dissolved water introduction section. And introducing the raw water subjected to coagulation treatment into the raw water introduction section, passing the raw water through the bubble zone in a downward flow, and then passing through the granular activated carbon biological filtration area. 2. An ozone reaction region is defined at an upper portion, and a granular activated carbon biological filtration region is defined at a lower portion. A raw water introduction portion is provided at an upper portion of the ozone reaction region, and an ozone dissolved water introduction portion is provided at a lower portion of the ozone reaction region. Purified water tank filled with granular activated carbon in the granular activated carbon biofiltration region, and ozone dissolved water pressurizing and introducing means for pressurizing dissolved water of ozone and air and introducing the ozone and water to the ozone dissolved water introduction unit, A raw water introducing means for introducing the raw water subjected to the coagulation treatment into the raw water introducing section. 3. The water purifier according to claim 2, wherein the ozone-dissolved water pressurizing and introducing means sucks and pressurizes a part of the treated water that has passed through the granular activated carbon biological filtration area, and introduces the ozone-dissolved water. A purifying apparatus comprising: a rotary vane type pump that discharges air to a section; and an ozone-containing air injecting unit that injects ozone-containing air into a suction side of the rotary vane type pump.