JPH10165989A - Water treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the contact with water to be treated with powdery active carbon longer and utilize the powdery active carbon effectively by providing the device with a biological filtration tank and a powdery active carbon treatment tank for injecting powdery active carbon into water to be treated, and returning a part of the water to be returned which has been treated with powdery active carbon to the biological filtration tank. SOLUTION: Water to be treated fed into a filtration tank main body 1 of a biological contact filtration tank (a) through an inflow pipe 2 is biologically treated, and then passed through a communication valve 16 and fed into a storage tank 17. Powdery active carbon is injected into water to be treated fed from the storage tank 17 into a powdery active carbon treatment tank (b) constituted of a tank main body 5 and a powdery active carbon injector 13 disposed in a tank positioned on the most upstream side out of a plurality of tanks. Chromaticity, odorous substances, trihalomethane precursor substances of biological hard-to-decompose properties, agricultural chemicals, surface active agents and the like in the water to be treated are removed by the powdery active carbon treatment, and then a part of the water to be treated is introduced into a following process, and residual water to be treated is returned to the biological filtration tank (a) through a return pipe 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powdered activated carbon treatment means for removing chromaticity and soluble organic substances, a biological treatment means for removing ammoniacal nitrogen and the like in a water purification treatment, The present invention relates to a water treatment apparatus provided with a filtration means for removing a substance.

[0002]

2. Description of the Related Art In recent years, some algae (Anabaena macrospo
ra, Phormidium tenue, Oscillatoria tenuis, etc.), the odorous substances produced cannot be completely removed by the existing water purification process, and the problem of off-flavors remaining in tap water as off-flavors has become noticeable. In addition, the contamination of raw tap water by organic substances represented by trihalomethane precursors and the like is becoming more serious. Further, chlorine used for sterilization and disinfection in the existing water purification process reacts with and binds to a trihalomethane precursor to produce trihalomethane, and there is a concern that tap water may be contaminated.

As a treatment method for addressing the above-mentioned problems, a so-called “advanced water treatment method” such as powdered activated carbon treatment and biological treatment (see “Guidelines for Introduction of Advanced Water Purification Facilities” issued by Japan Water Works Association, page 2) is described. It is being adopted in the water purification process.

[0004] In the powdered activated carbon treatment, powdered activated carbon is injected into the water to be treated, the substance to be removed dissolved in the water to be treated is adsorbed to the powdered activated carbon, and the substance to be removed is removed from the water to be treated. . The substances to be removed by the powdered activated carbon treatment include chromaticity, odor substances, trihalomethane precursors, pesticides, surfactants and the like.

A conventional water treatment apparatus employing the above-described powdered activated carbon treatment will be described with reference to FIG. FIG.
FIG. 1 is a schematic explanatory view showing a conventional water treatment apparatus. As shown in FIG. 5, the conventional water treatment apparatus has a powdered activated carbon treatment tank b.
And a coagulating sedimentation tank 14 and a sand filtration tank 15. The powdered activated carbon treatment tank b is provided at the treatment tank main body 5 to which the water to be treated is supplied via the inflow pipe 22 and at the inlet side of the treatment tank main body 5 and is used to inject the powdered activated carbon into the water to be treated. And a powdered activated carbon injector 13. The coagulation sedimentation tank 14 and the sand filtration tank 15 perform a solid-liquid separation process on the liquid to be treated that has been treated in the powdered activated carbon treatment tank b. That is, the coagulation / sedimentation tank 14 is connected to the powdered activated carbon treatment tank b via the communication pipe 23, and the sand filtration tank 15 is connected to the coagulation / sedimentation tank 14 via the communication pipe 24. The outflow pipe 25 is connected to the sand filtration tank 15, whereby the water to be treated filtered by the sand filtration tank 15 is discharged to the outside as water after the completion of the treatment.

That is, in the above-mentioned conventional water treatment apparatus, the powdered activated carbon treatment tank b includes the coagulation sedimentation tank 14 and the sand filtration The powdered activated carbon provided from the powdered activated carbon injector 13 in the powdered activated carbon treatment tank b is provided before the solid-liquid separation treatment means comprising the tank 15.
The powdered activated carbon that adsorbs the substance to be removed in the water to be treated and thus adsorbs the substance to be removed is removed by the coagulating sedimentation tank 14 and the sand filtration tank 15 together with the suspended substance in the water to be treated. Since such powdered activated carbon treatment can control the treatment capacity by controlling the amount of powdered activated carbon to be injected, it is an effective treatment method when the pollutant concentration in the water to be treated changes with the season. I can say.

On the other hand, when ammonia nitrogen, odorous substances, algae and the like are to be removed, biological treatment such as biological contact filtration treatment is employed. A biological contact filtration device related to this type of biological treatment is disclosed, for example, in Japanese Patent Publication No. 8-18029. Such a biological treatment has an advantage that a substantially constant treatment result can be obtained with respect to a change in the concentration of the pollutant flowing in without changing the operating conditions. According to the biological contact filtration device disclosed in Japanese Patent Publication No. 8-18029, it is possible to remove pollutants such as chromaticity, turbidity, ammonia nitrogen, Fe, Mn, and odorous substances. However, the document "WATER SCIENCE &TECHNOOG"
Y "31, No. 11, 229. Such biological treatment has an advantage that the cost is very low compared with other advanced water purification treatment methods, particularly because the power cost of the biological contact filtration device is mostly occupied by the power of the pump. I have.

[0008]

However, due to the powdered activated carbon treatment in the above-mentioned conventional water treatment apparatus,
Although it can remove chromaticity, odor substances, trihalomethane precursors, pesticides, surfactants, etc., it cannot remove some soluble substances such as ammonia nitrogen and suspended substances such as algae. . Further, in the above-described conventional water treatment apparatus, the powdered activated carbon injected into the water to be treated is configured to be removed by the coagulation sedimentation tank 14 and the sand filtration tank 15 located downstream of the powdered activated carbon treatment tank b. However, the fine powder of activated carbon to which the substance to be removed has been adsorbed cannot be completely removed by the coagulation sedimentation tank 14 and the sand filtration tank 15, and such fine powder of activated carbon is removed together with the water to be treated. There was a problem of being discharged outside. Such a problem occurs remarkably as the amount of the activated carbon powder injected into the liquid to be treated increases. As a result, the upper limit of the amount of powdered activated carbon to be injected is inevitably determined. For high-concentration pollutants that require an amount of powdered activated carbon to be injected that exceeds the upper limit, it cannot be completely removed. There was a problem that it was not possible.

Further, powdered activated carbon is expensive, for example, about 100,000 to 500,000 yen / m ³ depending on the type thereof. In view of such effective use, it is conceivable to lengthen the contact time between the water to be treated and the powdered activated carbon, but in that case, the powdered activated carbon treatment tank b becomes large, and the equipment cost and running cost increase. There was a problem of doing.

The biological treatment is effective for removing chromaticity, turbidity, ammoniacal nitrogen, Fe, Mn, odorous substances, and suspended substances such as algae. Simply by applying to the above-mentioned prior art apparatus, these pollutants could not be completely removed. Furthermore, regarding the removal of the trihalomethane precursor, which is a problem in the safety of tap water, by biological treatment, it is effective only for the biodegradable trihalomethane precursor, and is effective only for the biodegradable trihalomethane precursor. Material could not be removed.

Accordingly, an object of the present invention is to make it possible to remove chromaticity, odorous substances, pesticides, surfactants and the like, as well as turbidity, ammonia nitrogen, Fe, Mn, odorous substances and algae. Enables the removal of suspended substances, and further enables not only the biodegradable trihalomethane precursor but also the biorefractory trihalomethane precursor,
In addition, it prevents the fine powder of activated carbon from being discharged to the outside together with the water to be treated, and makes it possible to significantly increase the amount of powdered activated carbon to be injected into the liquid to be treated. Enables the treatment of high-concentration pollutants, which require high efficiency.In addition, it increases the contact time between the water to be treated and the powdered activated carbon without increasing the size of the powdered activated carbon treatment tank, and effectively uses the powdered activated carbon. Accordingly, an object of the present invention is to provide a water treatment apparatus capable of preventing an increase in equipment cost and running cost of a powdered activated carbon treatment tank.

[0012]

According to a first aspect of the present invention, a biological contact filtration tank to which water to be treated is supplied is connected via an inflow pipe to the biological contact filtration tank via a communication pipe. Injecting powdered activated carbon into the water to be treated from the biological contact filtration tank, mixing the powder with the water to be treated and contacting it with the water to be treated, and treating the water to be treated from the powdered activated carbon treatment tank at a later stage. An outlet pipe for leading to the treatment step, and a return pipe for returning a part of the water to be treated or a part of the water to be treated in the powdered activated carbon treatment tank to the biological contact filtration tank. In particular, it has features.

According to a second aspect of the present invention, there is provided a powdered activated carbon treatment tank for injecting powdered activated carbon into water to be treated supplied through an inflow pipe, mixing and contacting the same with the water to be treated, A biological contact filtration tank connected to the powdered activated carbon treatment tank via a communication pipe, an outflow pipe for leading water to be treated from the biological contact filtration tank to a subsequent treatment step, and a treatment pipe in the biological contact filtration tank And a return pipe for returning a part of the to-be-treated water or a part of the to-be-treated water to the powdered activated carbon treatment tank.

According to a third aspect of the present invention, in the apparatus according to the first or second aspect, the return pipe has a flow rate adjusting means for adjusting a return amount of the water to be treated. It has.

A fourth aspect of the present invention is characterized in that, in the apparatus according to the third aspect, the flow rate adjusting means comprises a pump. The invention described in claim 5 is characterized in that, in the apparatus described in claim 3, the flow rate adjusting means comprises a pump and a flow rate adjusting valve.

According to a fifth aspect of the present invention, in the apparatus according to any one of the first to fifth aspects, the return pipe has aeration means for increasing dissolved oxygen in the water to be treated. Is characterized by the fact that

[0017]

Next, a water treatment apparatus according to a first embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a schematic explanatory view showing a water treatment apparatus according to a first embodiment of the present invention.

[0018] The water treatment apparatus A according to the first embodiment of the present invention.
As shown in FIG. 1, a biological contact filtration tank a, a powdered activated carbon treatment tank b, an outflow pipe 7, a return pipe 8, a pump 9 as a flow rate adjusting means, an inverter 10, and a flow meter 11
It consists of

The biological contact filtration tank a is provided adjacent to the filtration tank main body 1, the granular medium layer 3 formed on the support layer 4 provided therein, and one side wall of the filtration tank main body 1. And a storage tank 17. Filtration tank body 1 and storage tank 1
7 communicates with each other only at the lower part of the one side wall of the filtration tank main body 1, and a communication valve 16 is provided at the communication portion for performing communication and shut-off between the two. Also, on the other side wall of the filtration tank body 1,
A drain valve 18 is provided above the granular medium layer 3. Although the storage tank 17 has been described as being provided adjacent to one side wall of the filtration tank main body 1,
It may be provided at a position separated by a predetermined interval from.

The water to be treated is supplied to the filtration tank main body 1 of the biological contact filtration tank a configured as described above through the inflow pipe 2, and the water to be treated supplied in this manner is a granular medium. The treated water that has passed through the layer 3 and the support layer 4 and is biologically treated, and thus biologically treated, is sent to the storage tank 17 through the communication valve 16.

The powdered activated carbon treatment tank b comprises a tank body 5 having a plurality of tanks, and a powdered activated carbon injector 13 provided in a tank located at the most upstream side among the plurality of tanks.
The powdered activated carbon injector 13 has any structure as long as it can inject the powdered activated carbon into the water to be treated supplied into the powdered activated carbon treatment tank b, and is constituted by, for example, a hopper. The powdered activated carbon treatment tank b configured as described above is connected to the above-mentioned storage tank 17 of the biological contact filtration tank a via the connecting pipe 6 at the entry side.

The outflow pipe 7 is connected to the above-mentioned powdered activated carbon treatment tank b.
Is connected to solid-liquid separation means (not shown) for a subsequent process, for example, a flocculation settling tank (not shown) and a sand filtration tank (not shown).

One end of the return pipe 8 is connected to the outflow pipe 7 described above, and the other end is connected to the inflow pipe 2 for supplying the water to be treated to the biological contact filtration tank a. As is clear from the above description, in the water treatment apparatus A according to the first embodiment of the present invention, the outflow pipe 7 for guiding the water to be treated flowing out of the powdered activated carbon treatment tank b to the subsequent process, and the biological contact filtration tank a is connected to the inflow pipe 2 for supplying the water to be treated by a return pipe 8 to form a loop and perform a circulation process.

The pump 9 serves as a means for adjusting the flow rate of the water to be treated flowing in the return pipe 8 described above.
Is provided on the way. The inverter 10 controls the rotation speed of the pump 9 to adjust the flow rate of the water to be treated flowing in the return pipe 8.

The flow meter 11 is provided in the return pipe 8 at a position downstream of the pump 9 with respect to the traveling direction of the water to be treated flowing in the return pipe 8. That is, the flow meter 11
Measures the flow rate of the water to be treated flowing through the return pipe 8 and sends a signal relating to the measured value to the inverter 10 described above. As described above, by using the pump 9, the inverter 10, and the flow meter 11 in combination, the rotation speed of the pump 9 is controlled in accordance with the flow rate of the water to be treated flowing in the return pipe 8, and thus the powder activated carbon treatment is performed. The flow rate of the water to be treated returned from the tank b to the biological contact filtration tank a is maintained at a predetermined value.

Next, the operation of the water treatment apparatus A according to the first embodiment of the present invention will be described. First, the water to be treated is supplied through the inflow pipe 2 into the filtration tank main body 1 of the biological contact filtration tank a. The water to be treated thus supplied passes through the granular medium layer 3 and the support layer 4 and is subjected to biological treatment, whereby the turbidity in the water to be treated, ammonia nitrogen, Fe, M
n, odor substances, biodegradable trihalomethane precursors, and suspended substances such as algae are removed. The water to be treated biologically treated in this way passes through the communication valve 16,
It is sent to the storage tank 17.

Next, the water to be treated sent to the storage tank 17 is supplied to the powdered activated carbon treatment tank b via the connecting pipe 6. Next, the powdered activated carbon from the powdered activated carbon injector 13 is injected into the water to be treated supplied into the powdered activated carbon treatment tank b in this manner, and the powdered activated carbon and the water to be treated are mixed in the treatment tank b. And they come into contact,
Thus, the powdered activated carbon treatment is performed to remove chromaticity, odorous substances, biodegradable trihalomethane precursors, pesticides, surfactants, and the like in the water to be treated.

Next, in the powdered activated carbon treatment tank b,
A part of the water to be treated, which has been subjected to the powdered activated carbon treatment, is guided to a subsequent process, but the rest of the water to be treated is returned to the biological contact filtration tank a via the return pipe 8. That is, the water to be treated returned to the biological contact filtration tank a in this way is subjected to biological treatment in the biological contact filtration tank a, and then to powdered activated carbon treatment in the powdered activated carbon treatment tank b, as described above. Part of the water to be treated, which has been subjected to the powdered activated carbon treatment, is guided to a subsequent process, but the rest of the water to be treated is returned to the return pipe 8.
Is returned to the biological contact filtration tank a again. In this way, the circulation treatment of the biological treatment and the powdered activated carbon treatment is performed.

Next, a method of backwashing the biological contact filtration tank a for eliminating trapped suspended substances in the granular medium layer 3 of the biological contact filtration tank a will be described with reference to FIG.
First, supply of new water to be treated into the biological contact filtration tank a,
In addition, the return of the water to be treated from the powdered activated carbon treatment tank b to the biological contact filtration tank a is stopped. In such a state,
By closing the communication valve 16 and opening the drain valve 18, the water level of the filtration tank body 1 is lowered to the position of the drain valve 18. Next, the communication valve 16 is opened. When the communication valve 16 is opened in such a state, the difference between the water to be treated in the filtration tank main body 1 and the water to be treated in the storage tank 17 causes a difference in the level of the storage tank 17.
The water to be treated flows back into the filter tank main body 1, whereby the granular medium layer 3 is washed, and the suspended substances trapped therein are removed. This backwashing has been described as being performed using the difference in water level between the water to be treated in the filtration tank main body 1 and the water to be treated in the storage tank 17, but the water to be treated is cleaned using a pump. By forcibly backflowing, the backwashing of the granular medium layer 3 in the biological contact filtration tank a can be performed.

According to the above-mentioned circulation treatment, the following effects are obtained: A part of the powdered activated carbon injected into the powdered activated carbon treatment tank b is returned to the biological contact filtration tank a together with the water to be treated. As a result, the contact time between the powdered activated carbon thus returned and the pollutants in the water to be treated can be lengthened,
Therefore, pollutants having an extremely low adsorption speed can be reliably removed. Since a part of the powdered activated carbon is captured by the granular medium layer 3 of the biological contact filtration tank a, even if the injection amount of the powdered activated carbon in the powdered activated carbon treatment tank b is greatly increased, it passes through the solid-liquid separation means at the subsequent stage. As a result, the amount of powdered activated carbon discharged to the outside can be significantly reduced. Organisms adhere to the surface of the powdered activated carbon captured in the granular medium layer 3 of the biological contact filtration tank a, so that powdered activated carbon usually used only for adsorption treatment can be used as a part of the biological treatment medium. it can. In addition, biological contact filtration tank a
The living organisms adhere to the surface of the powdered activated carbon in the water to be treated returned to the side and contribute to biological treatment.
It is possible to enhance the biological treatment function as compared with the case where is used alone. The powdered activated carbon trapped in the granular medium layer 3 of the biological contact filtration tank a is simultaneously eliminated by the above-described backwashing performed to eliminate other suspended substances trapped in the granular medium layer 3. Therefore, when algae and the like are actively captured and removed, the degree of clogging of the granular medium layer 3 should be adjusted to a level suitable for capturing algae by adjusting the frequency of backwashing, the amount of water, and the like. Can be. For this reason, it is possible to effectively use expensive powdered activated carbon. Removing pollutants that cannot be removed by powdered activated carbon treatment by biological contact filtration, while removing pollutants that cannot be removed by biological contact filtration by powdered activated carbon treatment, and removing pollutants while compensating for the disadvantages of both treatments Therefore, it is possible to cope with various pollutant removal processes.

Next, a water treatment apparatus according to a second embodiment of the present invention will be described in detail with reference to FIG. FIG.
FIG. 3 is a schematic explanatory view showing a water treatment apparatus according to a second embodiment of the present invention.

The water treatment apparatus B according to the second embodiment of the present invention
As shown in FIG. 2, a biological contact filtration tank a, a powdered activated carbon treatment tank b, an outflow pipe 7, a return pipe 8, a pump 9 as a flow control means, a flow meter 11, and a flow control valve 12, Consists of

The water treatment apparatus B according to the second embodiment of the present invention
A pump 9 for returning a part of the water to be treated on the powdered activated carbon treatment tank b side to the biological contact filtration tank a side is provided in a tank located on the most downstream side among a plurality of tanks of the powdered activated carbon treatment tank b. The present invention is described above, except that it is provided, an inverter for controlling the rotation speed of the pump 9 is not provided, and the flow regulating valve 12 is provided in the middle of the return pipe 8. It is the same as the water treatment apparatus A of the first embodiment. Therefore, the same reference numerals are given to the common components of these two components, and the description thereof will be omitted.

That is, in the water treatment apparatus A according to the first embodiment of the present invention, the pump 9 is provided in the middle of the return pipe 8, but the water treatment apparatus B according to the second embodiment of the present invention. In the above, the pump 9 is arranged in a tank located on the most downstream side among the plurality of tanks of the powdered activated carbon treatment tank b, and the return pipe 8 is connected to the discharge port of the pump 9 arranged in this way.
Are connected at the upstream end.

A flow meter 11 is provided in the middle of the return pipe 8 as in the water treatment apparatus A according to the first embodiment of the present invention. The return pipe 8 is provided at a position downstream of the flow meter 11 with respect to the traveling direction of the water to be treated flowing in the inside 8.

That is, the pump 9 in the water treatment apparatus A according to the first embodiment of the present invention has a rotation speed of the inverter 1.
0, so that the flow rate of the water to be treated is adjusted.
In the water treatment apparatus B of the embodiment, the rotation speed of the pump 9 is maintained within a predetermined range, and the flow rate of the water to be treated flowing in the return pipe 8 is adjusted by the above-described flow rate adjustment valve 12.

In the water treatment apparatus B according to the second embodiment of the present invention, the flow meter 11 is provided on the upstream side of the flow control valve 12, and measures the flow rate of the water to be treated before the flow rate is adjusted by the valve. However, it is also possible to provide the flow meter 11 on the downstream side of the flow regulating valve 12 and measure the flow rate of the water to be treated after the flow rate is regulated by the valve. .

The operation of the water treatment apparatus B according to the second embodiment of the present invention and the effects provided thereby are the same as the operation of the water treatment apparatus A according to the first embodiment of the present invention and the effects provided thereby, respectively. , And description thereof will be omitted.

Next, a water treatment apparatus according to a third embodiment of the present invention will be described in detail with reference to FIG. FIG.
FIG. 4 is a schematic explanatory view showing a water treatment apparatus according to a third embodiment of the present invention.

The water treatment apparatus C according to the third embodiment of the present invention
As shown in FIG. 3, a biological contact filtration tank a, a powdered activated carbon treatment tank b, an outflow pipe 7, a return pipe 8, a pump 9 as a flow control means, a flow meter 11, and a flow control valve 12 are provided.
And aeration means c.

The water treatment apparatus C according to the third embodiment of the present invention
Is the same as the water treatment apparatus B of the above-described second embodiment of the present invention except that the aeration means c is provided in the return pipe 8 on the downstream side of the flow control valve 12. Therefore, these common components are given the same reference numerals,
The description is omitted.

The aeration means c is provided in the return pipe 8 on the downstream side of the flow regulating valve 12 and has an aeration tank 19 provided with a downstream storage tank and an upstream storage tank which communicate with each other below.
A plurality of air injection nozzles 20 arranged at the bottom of the above-mentioned upstream storage tank of the aeration tank 19;
0 and a blower 21 connected via a pipe. In other words, the water to be treated flowing from the flow control valve 12 is returned to the biological contact filtration tank a via the upstream storage tank and the downstream storage tank of the aeration tank 19, but is returned to the inside of the upstream storage tank of the aeration tank 19. Air is blown into the water to be treated received from the plurality of air injection nozzles 20, whereby the amount of dissolved oxygen in the water to be treated is increased.

The operation of the water treatment apparatus C according to the third embodiment of the present invention is the same as the operation of the water treatment apparatus B according to the second embodiment of the present invention in the stage until the water to be treated passes through the flow control valve 12. It is. Therefore, the water to be treated is
The description of the operation of the water treatment apparatus C according to the third embodiment of the present invention in the stages up to the passage of is omitted.

The water to be treated that has passed through the flow control valve 12 is received in an upstream storage tank of the aeration tank 19. In this way, air is blown into the water to be treated received in the upstream storage tank from the plurality of air injection nozzles 20, whereby the amount of dissolved oxygen in the water to be treated increases. The water to be treated whose dissolved oxygen amount has increased in this way is returned to the biological contact filtration tank a via the return pipe 8 via the downstream storage tank of the aeration tank 19.

Therefore, according to the water treatment apparatus C of the third embodiment of the present invention, in addition to the effect brought about by the water treatment apparatus B of the second embodiment of the present invention, the water returned to the biological contact filtration tank a is added. The amount of dissolved oxygen in the treated water is increased to increase the biological treatment activity, thereby stabilizing the biological treatment effect and enhancing the biological regeneration effect of the powdered activated carbon, and reducing the cost of adding the powdered activated carbon.

Next, a water treatment apparatus according to a fourth embodiment of the present invention will be described in detail with reference to FIG. FIG.
FIG. 4 is a schematic explanatory view showing a water treatment apparatus according to a fourth embodiment of the present invention.

A water treatment apparatus D according to a fourth embodiment of the present invention
As shown in FIG. 4, a powdered activated carbon treatment tank b, a biological contact filtration tank a, an outflow pipe 7, a return pipe 8, a pump 9 as a flow rate adjusting means, a flow meter 11 and a flow rate adjustment valve 12, Consists of

A water treatment apparatus D according to a fourth embodiment of the present invention
Is constituted by replacing the biological contact filtration tank a and the powdered activated carbon treatment tank b in the water treatment apparatus B of the second embodiment of the present invention. That is, in the water treatment apparatus B according to the second embodiment of the present invention, the powdered activated carbon treatment tank b is disposed downstream of the biological contact filtration tank a, but the water treatment apparatus D according to the fourth embodiment of the present invention. In, the powdered activated carbon treatment tank b is disposed upstream of the biological contact filtration tank a. Therefore, in the water treatment apparatus B of the second embodiment of the present invention, the pump 9 connected to the upstream end of the return pipe 8 is located at the most downstream side of the plurality of tanks of the powdered activated carbon treatment tank b. Although disposed in the tank, in the water treatment apparatus D according to the fourth embodiment of the present invention, the pump 9 connected to the upstream end of the return pipe 8 is connected to the biological contact filtration tank a.
In the storage tank 17.

Except as described above, the water treatment apparatus D according to the fourth embodiment of the present invention is the same as the water treatment apparatus B according to the second embodiment of the present invention. Therefore, the same reference numerals are given to the common components of these two components, and the description thereof will be omitted.

Next, the operation of the water treatment apparatus D according to the fourth embodiment of the present invention will be described. First, the water to be treated is supplied to the powdered activated carbon treatment tank b via the inflow pipe 2. Next, the powdered activated carbon from the powdered activated carbon injector 13 is injected into the water to be treated supplied into the powdered activated carbon treatment tank b in this manner, and the powdered activated carbon and the water to be treated are mixed in the treatment tank b. The two are mixed and come into contact with each other, and thus the powdered activated carbon treatment is performed, and the chromaticity, odorant, biorefractory trihalomethane precursor, pesticide,
Surfactants and the like are removed.

Next, the water to be treated, which has been treated by the powdered activated carbon treatment tank b, is supplied through the communication pipe 6 into the filtration tank main body 1 of the biological contact filtration tank a. The water to be treated thus supplied passes through the granular medium layer 3 and the support layer 4 and is biologically treated, whereby turbidity, ammonia nitrogen, Fe, Mn, odorous substances, biological The easily decomposable trihalomethane precursor and suspended substances such as algae are removed. The to-be-processed water subjected to the biological treatment in this manner is sent to the storage tank 17 through the communication valve 16.

Next, in the biological contact filtration tank a, a part of the water to be treated which has been subjected to the biological treatment is led to a subsequent process, while the remaining water to be treated is powdered through the return pipe 8. It is returned to the activated carbon treatment tank b. That is, in the same manner as described above, the water to be treated returned to the powdered activated carbon treatment tank b is subjected to powdered activated carbon treatment in the powdered activated carbon treatment tank b, and then biologically treated in the biological contact filtration tank a. A part of the to-be-processed water subjected to the biological treatment is guided to a subsequent process, but the rest of the to-be-processed water is returned to the powdered activated carbon treatment tank b again through the return pipe 8. In this way, the circulation treatment of the powdered activated carbon treatment and the biological treatment is performed.

The backwashing method for the biological contact filter tank a for removing trapped suspended substances in the granular medium layer 3 of the biological contact filter tank a is the water treatment apparatus A according to the first embodiment of the present invention. Since the method is the same as that described above, the description thereof is omitted.

According to the water treatment apparatus D of the fourth embodiment of the present invention, in addition to the effects provided by the water treatment apparatus B of the second embodiment of the present invention, the activated carbon powder treatment tank b is replaced with a biological contact filtration tank a. Since it is arranged on the more upstream side, even if the water to be treated is not returned to the powdered activated carbon treatment tank b side, that is, the powdered activated carbon treatment tank b and the biological contact filtration tank a
, The residence time of the powdered activated carbon in the water treatment device D can be taken to some extent, and the operation is performed under the condition that the ratio of the return amount of the treated water to the total treated water amount is low. This is particularly advantageous in cases.

[0055]

As described above, according to the present invention, it is possible to remove chromaticity, odorous substances, pesticides, surfactants and the like, as well as turbidity, ammonia nitrogen, Fe, M
n, removal of suspended substances such as odorous substances and algae, and furthermore, removal of not only biodegradable trihalomethane precursors but also biodegradable trihalomethane precursors, and activated carbon Prevents the fine powder from being discharged to the outside together with the water to be treated, enabling a large increase in the amount of powdered activated carbon injected into the liquid to be treated, and requiring a large amount of powdered activated carbon to be injected. High-concentration pollutants can be treated, and the contact time between the water to be treated and the powdered activated carbon can be extended without increasing the size of the powdered activated carbon treatment tank, thereby effectively utilizing the powdered activated carbon effectively. Therefore, it is possible to provide a water treatment apparatus capable of preventing an increase in equipment cost and running cost of the powdered activated carbon treatment tank, and thus a useful effect is provided.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a water treatment apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing a water treatment apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic explanatory view showing a water treatment apparatus according to a third embodiment of the present invention.

FIG. 4 is a schematic explanatory view showing a water treatment apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a schematic explanatory view showing a conventional water treatment apparatus.

[Explanation of symbols]

 A: Water treatment apparatus of the first embodiment of the present invention B: Water treatment apparatus of the second embodiment of the present invention C: Water treatment apparatus of the third embodiment of the present invention D: Water of the fourth embodiment of the present invention Treatment equipment E: Conventional water treatment equipment a: Biological contact filtration tank b: Powder activated carbon treatment tank c: Aeration means 1: Filtration tank body 2: Inflow pipe 3: Granular media layer 4: Support layer 5: Tank body 6: Communication Pipe 7: Outflow pipe 8: Return pipe 9: Pump 10: Inverter 11: Flow meter 12: Flow control valve 13: Powder activated carbon injector 14: Coagulation sedimentation tank 15: Sand filtration tank 16: Communication valve 17: Storage tank 18: Drain valve 19: Aeration tank 20: Air injection nozzle 21: Blower 22: Inflow pipe 23, 24: Communication pipe 25: Outflow pipe

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C02F 1/28 C02F 1/28 D 3/06 3/06 (72) Inventor Takao Shuto 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside Steel Pipe Co., Ltd.

Claims (6)

[Claims] 1. A biological contact filtration tank to which water to be treated is supplied via an inflow pipe, and a biological contact filtration tank connected to the biological contact filtration tank via a communication pipe, wherein powder to be treated from the biological contact filtration tank is powdered. A powdered activated carbon treatment tank for injecting the activated carbon and mixing and contacting it with the water to be treated, an outlet pipe for guiding the water to be treated from the powdered activated carbon treatment tank to a subsequent treatment step, A water treatment apparatus comprising: a return pipe for returning a part of the water to be treated or a part of the water to be treated in the treatment tank to the biological contact filtration tank. 2. A powdered activated carbon treatment tank for injecting powdered activated carbon into water to be treated supplied through an inflow pipe and mixing and contacting the same with the water to be treated, and a connecting pipe connected to the powdered activated carbon treatment tank. A biological contact filtration tank connected via a, an outflow pipe for guiding the water to be treated from the biological contact filtration tank to a subsequent treatment step, and a part of the water to be treated in the biological contact filtration tank Or a return pipe for returning a part of the water to be treated during the treatment to the powdered activated carbon treatment tank. 3. The apparatus according to claim 1, wherein the return pipe has a flow rate adjusting means for adjusting a return amount of the water to be treated. 4. The apparatus according to claim 3, wherein said flow control means comprises a pump. 5. The apparatus according to claim 3, wherein said flow control means comprises a pump and a flow control valve. 6. The apparatus according to claim 1, wherein the return pipe has aeration means for increasing dissolved oxygen in the water to be treated.