JPH10290993A - Purified water treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the site area of equipment small, to facilitate the operation control, to make the equipment installation cost and the operational cost inexpensive and to obtain city water with a high degree of water quality. SOLUTION: This purified water treating apparatus is one for obtaining city water from raw water from such as rivers, lakes and marshes, pounds and underground water. This device is provided with a treating tank 1 sectioned to a microorganism treating part 5 where the raw water is fed and a membrane filtration part 6 with a partitioning wall 4. Granular activated carbon 7 where the aerobic microorganisms is stuck on the surface is held in the microorganism treating part 5. A filter membrane unit 8 is arranged at the membrane filter part 6. A transfer means for feeding the liquid in the tank treated with the microorganism treating part 5 to the membrane filter part 6 is provided on the apparatus.

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 apparatus for obtaining clean water from raw water such as river water, lake water, pond water, and groundwater.

[0002]

2. Description of the Related Art A conventional general water purification method mainly involves the removal and sterilization of suspended matter. As shown in FIG. 2, chlorine is injected into raw water and then coagulated. A coagulant is formed by adding an appropriate coagulant in the sedimentation tank to precipitate it, and then guided to a sand filtration tank filled with sand for filtration, and chlorine is injected again.

However, in such a method, the site area of facilities required for the amount of treated water becomes large, and maintenance of delicate operating conditions based on abundant experience is indispensable. That is, in order to maintain a good state of coagulation sedimentation and filtration in response to a change in the state of raw water, fine adjustment of many operating parameters such as chemical injection conditions is required.

Further, in recent years, the quality of raw tap water such as lake water and groundwater has been remarkably deteriorated, causing problems such as off-flavor and generation of trihalomethane. However, the conventional general water purification method can solve these problems. Since it is impossible, more advanced processing technology is required, and various developments have been made in response to this demand. FIG. 3 shows an example of a currently known advanced water purification treatment method. In FIG. 3, the advanced water purification method uses a coagulation sedimentation tank in which a suitable coagulant is added to raw water to form a coagulate, which is precipitated, followed by blowing ozone, and then a sand filtration tank filled with sand. And then blown ozone again, then flowed into the tank filled with granular activated carbon from above and formed a downward flow in the tank to adsorb organic substances etc. on the granular activated carbon, and further chlorine Is to be injected.

[0005] However, such a method is very complicated as compared with the conventional general water purification method, and has a problem (the area of the facility premises) of the general water purification method described above. And the need for delicate operation management techniques), equipment construction costs and operation costs rise significantly, and the resulting cost of clean water rises significantly. .

Further, a method using a separation membrane has been considered as an advanced water purification method. However, in order to cope with the problem of off-flavor and trihalomethane generation, a reverse osmosis membrane (low pressure, also called a nanofiltration membrane) is used. (Including reverse osmosis membrane) is indispensable. In the case of this method, there are problems that the cost of the membrane is increased, a pretreatment technique for avoiding performance degradation due to fouling of the membrane is complicated, and the pump power is also excessive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to reduce the site area of equipment, to facilitate operation management, to reduce equipment construction costs and operation costs, and to obtain a high quality water purification system. Is to provide.

[0008]

Means for Solving the Problems and Effects of the Invention A water purification apparatus according to the present invention is a water purification apparatus for obtaining clean water from raw water such as river water, lake water, pond water, and groundwater. , A treatment tank partitioned into a microorganism treatment section and a membrane filtration section to which raw water is supplied, granular activated carbon retained in the microorganism treatment section and having aerobic microorganisms adhered to the surface, and disposed in the membrane filtration section It is provided with a filtration membrane unit and a transfer means for sending the liquid in the tank treated by the microorganism treatment section to the membrane filtration section.

A water purification method using the water purification apparatus according to the present invention is as follows. That is, raw water is supplied into the microbial treatment section of the treatment tank, and the organic matter in the tank liquid, which is the raw water put into the treatment tank, is adsorbed on the activated carbon surface, and the organic matter is decomposed by the aerobic microorganisms, and the organic matter is decomposed. The solution in the tank containing the decomposed product and other suspended matter is sent to the membrane filtration unit by the transfer means, where the suspended matter and bacteria are filtered out by the filtration membrane unit.

[0010] According to the water purification method using the water purification apparatus according to the present invention, the number of processes is reduced as compared with the above-mentioned two conventional water purification methods. Therefore, operation management is facilitated and operation costs are reduced. In addition, since trihalomethane precursors and organic substances that are off-flavor-causing substances are adsorbed on activated carbon or decomposed by aerobic microorganisms, trihalomethane generation and off-flavor generation can be prevented. In addition, since other suspensions are separated by the filtration membrane unit, suspended solids and bacteria are also removed. Therefore, a high level of clean water is obtained. In addition, since organic matter is decomposed by aerobic microorganisms, a relatively inexpensive microfiltration membrane or ultrafiltration membrane can be used as a membrane used for the filtration membrane unit, and equipment costs are reduced. Furthermore, when the raw water is river water, the organic matter in the raw water is diluted, so that the decomposition efficiency by microorganisms may be reduced or the microorganisms may not survive. Since it is adsorbed on the activated carbon, the organic matter in the raw water is concentrated, preventing the degradation efficiency of the microorganisms from deteriorating and ensuring the survival of the microorganisms.

In addition, the water purification apparatus of the present invention is characterized in that the partition wall separates a treatment tank partitioned into a microorganism treatment section and a membrane filtration section to which raw water is supplied, and that aerobic microorganisms held in the microorganism treatment section and whose surface has aerobic microorganisms. With granular activated carbon adhering,
Since only the filtration membrane unit arranged in the membrane filtration unit and the transfer means for sending the liquid in the tank treated in the microbial treatment unit to the membrane filtration unit are provided, the site area of the facility is the same as the conventional one described above. It is smaller than an apparatus for implementing the two methods. Further, the equipment construction cost and the operation cost are lower than those of the apparatus for performing the above two conventional methods.

[0012] In the above water purification treatment apparatus, it is preferable that an aeration apparatus is disposed below the microorganism treatment section, and an aeration apparatus is disposed below the filtration membrane unit of the membrane filtration section.
In this case, when the liquid in the tank in each part is aerated using these aerators, a circulating flow of the liquid in the tank is formed in each part, and the activated carbon also circulates along the circulating flow in the microbial treatment section, and organic matter is removed. The efficiency of contact with activated carbon is improved, and the organic matter adsorption rate on activated carbon is also improved. In addition, since dissolved oxygen does not stay, an appropriate aerobic condition is maintained, the amount of microorganisms per unit volume increases, and the organic matter decomposing effect is improved. On the other hand, in the membrane filtration section, the deposits on the membrane surface are peeled off by the bubbles in the circulating flow, so that clogging of the membrane is prevented, and continuous processing over a long period of time becomes possible. Moreover, since the aeration device is arranged in each of the microorganism treatment section and the membrane filtration section,
The amount of aeration of the liquid in the tank in each part can be adjusted to an amount suitable for microbial treatment by aerobic microorganisms attached to the granular activated carbon and membrane filtration by a filtration membrane unit. That is, if the amount of aeration to the microbial treatment section is too large, the aerobic microorganisms adhering to the activated carbon surface are peeled off due to the contact between the activated carbons, and the efficiency of the organic matter decomposition treatment by the microorganisms is reduced. On the other hand, in the membrane filtration section, if the amount of aeration is too small, the effect of removing adhering substances on the membrane surface is small, and if the amount of aeration is too large, the power cost increases.

In the above-mentioned water purification apparatus, the granular activated carbon may be crushed coal of crushed coal raw material or crushed coconut shell raw material having a particle size of 0.2 to 2 mm. In this case, even if the granular activated carbon enters the membrane filtration unit, the passage of the activated carbon through the membrane and the clogging of the membrane due to the activated carbon are prevented.

[0014] In the above-mentioned water purification apparatus, the microbial treatment section of the treatment tank may further contain powdered activated carbon having aerobic microorganisms attached to the surface. The particle size of the powdered activated carbon is about 20 to 200 μm. In this case, since the specific surface area of the powdered activated carbon is larger than that of the granular activated carbon, the adsorption rate of organic substances is improved, and as a result, the efficiency of decomposition of organic substances by aerobic microorganisms is also improved. Therefore, it is effective when the quality of the raw water is particularly poor or when it is desired to further improve the quality of the obtained clean water. The pore size of the membrane is 0.4μ
m, the clogging of the membrane with the powdered activated carbon and the passage of the powdered activated carbon through the membrane are prevented even if the powdered activated carbon enters the membrane filtration section.

In the above-mentioned water purification apparatus, the filtration membrane unit may include a microfiltration membrane or an ultrafiltration membrane. In this case, the cost is reduced.

In the above-mentioned water purification apparatus, the transfer means for sending the liquid in the tank treated by the microorganism treatment section to the membrane filtration section comprises a liquid level raising means for increasing the liquid level of the liquid in the tank in the microorganism treatment section. It is preferable that the liquid level of the liquid in the tank in the microorganism treatment section is raised by the surface raising means, and the liquid is overflowed from above the partition wall and sent to the membrane filtration section. In this case, there is no need for a pipe or a pump for sending the liquid in the tank treated in the microorganism treatment section to the membrane filtration section, and the installation work for these is not required. In addition, when the liquid in the tank treated by the pump is sent from the microbial treatment section to the membrane filtration section through the piping, the piping may be clogged by hardly decomposable insoluble organic substances and other suspended matter, and maintenance is troublesome. However, there is no need for such maintenance if overflow is made from above the partition wall and sent to the membrane filtration membrane. In addition, power costs can be reduced as compared with the case where a pump is used.

In the above-mentioned water treatment apparatus, a baffle for preventing the outflow of activated carbon projecting inward into the microbial treatment section is provided at the upper end of the surface of the partition wall facing the microbial treatment section so as to be inclined downward toward the tip. May be. in this case,
Even if the activated carbon rises to the vicinity of the liquid surface by the function of the baffle plate, the activated carbon does not rise further by hitting the baffle plate, so that it can be surely prevented from entering the membrane filtration section from above the partition wall. In addition, when the aeration device is disposed in the microorganism treatment unit, even if the activated carbon is moved above the baffle plate by the upward flow formed by this,
Since the upward flow near the partition wall by the aeration device is stopped by the baffle plate, the activated carbon falls on the baffle plate and rolls down along the upper surface thereof in combination with the large specific gravity of the activated carbon.

[0018] In the above-mentioned water purification treatment apparatus, it is preferable to dispose a separation tank for sedimentation and sedimentation of coarse substances and easily sedimented substances in the raw water on the upstream side of the treatment tank. in this case,
Before putting the raw water into the treatment tank, coarse substances and easily sedimented substances in the raw water can be settled and separated in the settling tank. In this case, since bulky substances do not enter the membrane filtration section,
Damage to the membrane of the filtration membrane unit due to a bulky substance or the like can be prevented.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings.

FIG. 1 shows the overall structure of a water purification apparatus according to the present invention. In FIG. 1, the water purification treatment device is a treatment tank.
(1) A sedimentation separation tank (2) which is located upstream of the treatment tank (1) and sediments and separates coarse and easy sediment in raw water
And a water storage tank (3) arranged downstream of the treatment tank (1) for storing the obtained clean water.

The inside of the treatment tank (1) is divided into a microorganism treatment section (5) and a membrane filtration section (6) by a partition wall (4). The microbial treatment section (5) has a large number of granular activated carbons (7) to which aerobic microorganisms adhere, and the membrane filtration section (6) is provided with a filtration membrane unit (8). As the activated carbon (7), crushed coal of coal raw material or crushed coal of coconut shell raw material is optimal, but granulated activated carbon can also be used. The particle size of the activated carbon (7) is preferably in the range of 0.1 to 5 mm,
The range of 0.2 to 2 mm is optimal. In addition, activated carbon
The larger the average pore diameter of (7), the better.

The filtration membrane unit (8) includes a plurality of hollow flat membrane modules (9). Although not shown, each flat membrane module (9) is composed of two flat membranes arranged in opposition, and a frame spacer arranged between the peripheral portions of both flat membranes. A suction pipe (10) is connected to each flat membrane module (9) so as to communicate with the inside of the hollow part. Each suction tube (10)
Are connected collectively to one filtered water pipe (11) extending from the water storage tank (3). In the middle of the filtration water pipe (11), a suction pump (1
2) is provided, and the liquid in the tank of the membrane filtration section (6) passes through the flat membrane and is sucked into the flat membrane module (9) by the suction pump (12). As the flat membrane of the flat membrane module (9), an ultrafiltration membrane or a microfiltration membrane is used. Among them, it is preferable to use a microfiltration membrane having a relatively small suction resistance and a low cost. In addition, a capillary module using a hollow fiber membrane can be applied to the filtration membrane unit (8) instead of the flat membrane module (9) using a flat membrane.

At the bottom of the microorganism treatment section (5), a settling tank
(2) The end of the raw water supply pipe (13) extending from
The pump (14) feeds the raw water from the sedimentation tank (2) through the raw water supply pipe (13) to the bottom of the microorganism treatment section (5). An aeration device (15) is arranged below the lower end of the raw water supply pipe (13) in the microbial treatment section (5). Air is blown into the aeration device (15) by the blower (16). At the upper end of the surface of the partition wall (4) facing the microorganism treatment section (5), a baffle plate (17) for preventing activated carbon outflow protruding inward is inclined downward toward the tip. It is provided in the shape. In addition, a water drain pipe (18) is connected to the upper end of the part of the peripheral wall of the treatment tank (1) facing the microorganism treatment part (5), and an open / close valve (19) is provided in the water drain pipe (18). I have.

An aeration device (21) is also arranged in a portion of the membrane filtration section (6) in the treatment tank (1) below the filtration membrane unit (8). Air is sent into the aeration device (21) by the blower (22). Further, the membrane filtration unit (6)
Level sensor (2
3). Level sensor (23) and settling tank
Pump (14) that supplies raw water from (2) to the microbial treatment section (5)
Is connected to the controller (24), and the level sensor (23), the pump (14) and the controller (24) raise the liquid level of the liquid in the tank in the microorganism treatment section (5), and The liquid level rising means constitutes a means for transferring the liquid in the tank which overflows from above the wall (4) and is sent to the membrane filtration section (6).
The liquid level raising means is provided to the microorganism treatment unit (5) so that the liquid level of the liquid in the tank in the membrane filtration unit (6) is always above the upper end of the filtration membrane unit (8) and does not become too high. Of raw water supply. Also, the membrane filtration section on the peripheral wall of the processing tank (1)
A water drain pipe (25) is connected to the lower end of the portion facing (6), and the water drain pipe (25) is provided with an on-off valve (26).

Next, a water purification method using the above apparatus will be described.

In the sedimentation tank (2), coarse substances and easily sedimentary substances in raw water such as river water, lake water, pond water, and groundwater containing a trihalomethane precursor and an off-flavor-causing substance are previously settled and separated. Raw water is supplied to the microorganism treatment section (5) in the treatment tank (1) by the pump (14). Normally, the on-off valves (19) and (26) of the water drainage pipes (18) and (25) in the microorganism treatment section (5) and membrane filtration section (6)
Is closed.

Then, air is blown into the aeration device (15) by the blower (16) to aerate the liquid in the tank of the microorganism treatment section (5). Then, the organic matter in the tank liquid is adsorbed on the activated carbon (7) surface and decomposed by the aerobic microorganisms. When the liquid in the tank of the microorganism processing section (5) is aerated, a circulation flow of the liquid in the tank is formed in the microorganism processing section (5) in the processing tank (1) by an air lift effect. That is, the liquid in the tank, the granular activated carbon (7) and the bubbles rise, and the bubbles are released into the atmosphere when they reach the surface of the water, and the liquid in the tank and the granular activated carbon (7) flow downward and pass through the microbial treatment section (5). It reaches the bottom and rises again with bubbles. Unwanted organic matter present in raw water is
Adsorbed on the circulating activated carbon (7) and concentrated on the activated carbon (7) surface. Since the activated carbon (7) also circulates in this circulation flow, the contact efficiency with the organic matter is improved, and the organic matter adsorption rate on the activated carbon (7) is also improved. In addition, organic substances that are difficult to bio-process efficiently at the same concentration in raw water are easily and efficiently degraded by microorganisms attached to the activated carbon (7) surface when concentrated on the activated carbon (7) surface. You. Activated carbon (7)
Since the organic matter adsorbed on the activated carbon (7) is sequentially decomposed by the attached microorganisms, the performance of the activated carbon (7) is prevented from deteriorating due to saturated adsorption. In addition, oxygen necessary for decomposing organic substances into aerobic microorganisms is efficiently supplied.

When the water level of the microorganism treatment section (5) in the treatment tank (1) becomes higher than the partition wall (4), the liquid in the tank overflows and is sent to the membrane filtration section (6). The liquid in the tank contains suspended products such as decomposition products of organic substances, suspended solids, bacteria, and insoluble organic substances. At this time, the membrane filtration unit (6)
The water level is determined by the level sensor (23), pump (14) and controller
By controlling the supply amount of the raw water to the microbial treatment section (5) by (24), the raw water is always adjusted above the upper end of the filtration membrane unit (8) and adjusted so as not to be too high.

When the liquid in the tank of the microorganism treatment section (5) overflows and is sent to the membrane filtration section (6), the specific gravity of the activated carbon (7) is large, so that the activated carbon (7) floats up to near the liquid level. As a result, it is possible to prevent the activated carbon (7) from flowing out to the membrane filtration section (6). Therefore, it is economical because it is not necessary to renew the activated carbon (7) in order to maintain the processing ability of the organic matter by the microorganism and the ability to adsorb the activated carbon (7). Microorganism treatment unit (5) by aeration device (15)
If the liquid in the tank is aerated, the activated carbon (7) may rise to near the liquid level, but the activated carbon outflow baffle (17)
Even if the activated carbon (7) rises to near the liquid level, the activated carbon (7) hits the baffle plate (17) and does not rise any further, so that the outflow to the membrane filtration section (6) is ensured. Can be prevented. Moreover, even if the activated carbon (7) moves above the baffle plate (17), the upflow near the partition wall (4) by the aeration device (15) is stopped by the baffle plate (17). (7) coupled with the high specific gravity of
(7) falls on the baffle plate (17) and rolls down along its upper surface.

When the liquid in the tank is sent to the membrane filtration section (6),
By blowing air into the aeration device (21) with the blower (22), while aerating the liquid in the tank from below the filtration membrane unit (8),
Suction is performed by the suction pump (12). Then, suspended solids such as suspended solids and bacteria are converted into the flat membrane module (9) of the filtration membrane unit (8).
The filtered water that has been filtered by the flat membrane of
(10) and the filtered water pipe (11) to the water tank (3). The raw water may contain viruses.Because the flat membrane does not have a virus removal function, and to avoid microbial contamination during the water distribution process, filter water before sending it to the water storage tank (3). (11) An appropriate amount of chlorine is injected into the filtered water flowing in the tank, and stored in the water storage tank (3) as clean water.

When the liquid in the tank is aerated from below the filtration membrane unit (8), a circulating flow of the liquid in the tank is formed in the membrane filtration section (6) in the processing tank (1) by an air lift effect. That is,
The liquid in the tank and bubbles rise between the flat membrane modules (9) adjacent to the filtration membrane unit (8), and the bubbles are released into the atmosphere when they reach the water surface, and the liquid in the tank is treated with the filtration membrane unit (8). Tank
It flows downward between the peripheral wall of (1) and the partition wall (4) to reach the lower side of the filtration membrane unit (8), and again together with air bubbles, the flat membrane module (8) adjacent to the filtration membrane unit (8). 9)
Rise between. At this time, turbulence is given to the flow rising between the flat membrane modules (9) adjacent to the filtration membrane unit (8) by aeration into the liquid in the tank from below the filtration membrane unit (8). Then, bubbles rising between the adjacent flat membrane modules (9) of the filtration membrane unit (8) rub against the flat membrane, thereby removing the deposits on the flat membrane surface, thereby preventing the flat membrane from being clogged. Thus, continuous processing over a long period of time becomes possible.

As the operation time becomes longer, the concentration of the suspension in the liquid in the tank in the microorganism treatment section (5) in the treatment tank (1) increases. At this time, if the on-off valve (23) is opened, the liquid in the tank in which the concentration of the suspended matter has increased can be extracted from the water extraction pipe (18).

When the liquid in the tank is withdrawn from the water drain pipe (18), it is possible to prevent the activated liquid (7) from being contained in the liquid in the tank withdrawn. That is, since the specific gravity of the activated carbon (7) is large, the activated carbon (7) does not float to the vicinity of the liquid surface, and as a result, it is possible to prevent the activated carbon (7) from flowing out of the drain pipe (18). The activated carbon (7) can be prevented from flowing out.
It is economical because there is no need to renew (7).
If the liquid in the tank is aerated from the lower part of the microorganism treatment part (5), the activated carbon (7) may rise to near the liquid level,
In this case, the activated carbon (7) is reduced by reducing the amount of aeration by the aerator (15) when extracting the liquid in the tank from the microbial treatment section (5).
Is adjusted not to rise to near the liquid level.

When the operation time becomes longer, the processing tank (1)
The concentration of the suspension of the liquid in the tank in the membrane filtration section (6) in the inside also becomes high as in the case of the microorganism treatment section (5). At this time, if the on-off valve (26) is opened, the liquid in the tank in which the concentration of the suspended matter has increased can be extracted from the water extraction pipe (25). Therefore, it is possible to prevent an increase in the differential pressure of the membrane at the time of filtration, and to prevent clogging of the flat membrane by the suspended matter.

In the above embodiment, the microbial treatment section (5) of the treatment tank (1) is provided with granular activated carbon to which aerobic microorganisms adhere.
(7), but the microorganism treatment section (5) of the treatment tank (1)
Has a particle size of 20 to 200 in addition to the granular activated carbon (7).
In some cases, powdered activated carbon of about μm is incorporated. In this case, since the specific surface area of the powdered activated carbon is larger than that of the granular activated carbon (7), the adsorption rate of organic substances is improved, and as a result, the decomposition efficiency of organic substances by aerobic microorganisms is also improved.
Therefore, it is effective when the quality of the raw water is particularly poor or when it is desired to further improve the quality of the obtained clean water. As the powdered activated carbon, as in the case of the granular activated carbon (7), crushed coal of coal raw material or crushed carbon of coconut shell raw material is optimal, but granulated activated carbon can also be used.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a water purification treatment device of the present invention.

FIG. 2 is a flow sheet showing a conventional general water purification method.

FIG. 3 is a flow sheet showing a conventional advanced water purification method.

[Explanation of symbols]

 (1): Treatment tank (4): Partition wall (5): Microorganism treatment section (6): Membrane filtration section (7): Granular activated carbon (14): Pump (23): Level sensor (24): Controller

Claims (8)

[Claims] 1. A water purification apparatus for obtaining clean water from raw water such as river water, lake water, pond water, groundwater, etc., which is partitioned by a partition wall into a microorganism treatment section and a membrane filtration section to which raw water is supplied. Treatment tank, granular activated carbon retained in the microbial processing unit and having aerobic microorganisms adhered to the surface, the filtration membrane unit disposed in the membrane filtration unit, and the tank solution treated in the microbial treatment unit A water purification treatment device comprising a transfer means for sending to a membrane filtration unit. 2. The water purification treatment apparatus according to claim 1, wherein an aeration device is arranged below the microorganism treatment unit, and an aeration device is arranged below the filtration membrane unit of the membrane filtration unit. 3. The water purification treatment apparatus according to claim 1, wherein the granular activated carbon is a crushed coal of coal raw material or a crushed coal of coconut shell raw material having a particle size of 0.2 to 2 mm. 4. The water purification apparatus according to claim 1, wherein the microbial treatment section of the treatment tank further holds powdered activated carbon having aerobic microorganisms attached to the surface. 5. The water treatment apparatus according to claim 1, wherein the filtration membrane unit includes a microfiltration membrane or an ultrafiltration membrane. 6. A transfer means for sending the liquid in the tank treated by the microorganism treatment part to the membrane filtration part comprises a liquid level rising means for raising the liquid level of the liquid in the tank in the microorganism treatment part. The water purification treatment device according to any one of claims 1 to 5, wherein the liquid level of the liquid in the tank in the microorganism treatment unit is raised, overflows from above the partition wall, and is sent to the membrane filtration unit. 7. An activated carbon outflow baffle protruding inwardly of the microbial treatment section is provided at an upper end of a surface of the partition wall facing the microbial treatment section and is inclined downward toward the tip. The water purification device according to any one of 1 to 6. 8. The method according to claim 1, wherein a separation tank is provided on the upstream side of the treatment tank so as to settle and separate coarse and easy sediment in raw water. The water purification device according to the above.