JP2003230895A - Method and apparatus for treating manganese-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove soluble manganese under a low water temperature environment with high efficiency in a membrane treatment system. <P>SOLUTION: A membrane filter apparatus A is constituted by immersing membrane modules 21 having outer pressure tube type membrane elements 22 incorporated therein in a membrane immersion tank 20 and an air diffusion pipe 27 in the membrane immersion tank 20 and used as membrane treatment equipment. A chlorine contact basin, which has a hypochlorite blending tank 1 and a powder carbon adsorption tank 7 respectively provided to the front and rear parts thereof, is provided in combination with the membrane filter apparatus A. Chlorine is injected in raw water (a) to convert soluble manganese present in raw water to manganese dioxide. Then, the manganese dioxide- containing raw water is sent to the membrane filter apparatus A by suppressing the formation of a disinfection byproduct not only to perform treatment due to residual free chlorine and manganese oxide concentrated in the tank but also to perform the filtering and separation of a turbid substance (solid component) to take out clean water. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment method using membrane filtration of river water or well water containing manganese.
The present invention relates to a method for treating manganese-containing water capable of removing organic matter, manganese, and ammonia at a high rate even in a low water temperature environment in a tank-immersed membrane filtration method, and an apparatus thereof.

[0002]

2. Description of the Related Art A water treatment method by membrane filtration is a method for realizing low cost such as easy maintenance and space saving as compared with the conventional rapid filtration method. Attention is being paid to the introduction of membrane treatment into the. However, there are various types of membrane treatment methods, but these have a problem that high turbidity water and high manganese water cannot be directly filtered.

However, the raw water treated in the water purification plant has high turbidity and often contains a large amount of soluble organic substances and manganese. Therefore, in the treatment of such raw water,
Pretreatment such as coagulation and precipitation is required before the membrane treatment, and a dedicated treatment device is also required for soluble organic substances and manganese. As a result, the entire processing equipment has to undergo a multi-step processing process, resulting in high cost for initial and maintenance, and a space problem. For example, if a manganese removal facility for manganese sand filtration is installed in the preceding stage of the membrane filtration facility (see Fig. 4- (1)), the filter bed will be clogged during high turbidity, and the manganese removal facility will be used for membrane filtration. When it is installed in the latter part of the equipment (see Fig. 4- (2)), the manganese penetrating into the membrane promotes fouling of the membrane, and the advantage of membrane treatment is lost.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is highly turbid and has a low water temperature by combining a tank-immersed membrane filtration method with chlorine oxidation or chlorine oxidation and powdered activated carbon adsorption treatment. It is intended to provide a water treatment method and an apparatus therefor capable of performing a stable operation even in raw water, and achieving a high removal rate of organic substances, manganese, and ammonia.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted a number of studies and experiments and as a result, as a membrane treatment method, SS in a membrane immersion tank capable of performing microfiltration High concentration of manganese-containing pollutants with extremely simple flow by using an immersion type membrane filtration device that employs a filtration membrane capable of concentrating the concentration to 3000 to 10,000 mg / l and combining this with chlorine oxidation and powdered activated carbon adsorption treatment. The inventors have found a method capable of treating system raw water at a high removal rate and have completed the present invention.

In the present invention, an immersion type membrane filtration device equipped with aeration means is used as the membrane treatment. This membrane filtration device
Since the filter medium is of the tank immersion type, the membrane spacing is wide, and it is constantly aerated, it is possible to increase the SS concentration in the membrane immersion tank and perform biological treatment of ammonia and manganese (soluble manganese). Becomes Further, a ceramic membrane, an organic hollow fiber membrane or the like is used as the filter medium.

In the present invention, in combination with the above-mentioned membrane filtration device, a hypochlorite (free chlorine) mixing tank for oxidizing soluble manganese in raw water into manganese dioxide is provided in the preceding stage, followed by hypoinjection. Install a chlorine contact pond equipped with a powdered coal adsorption tank that suppresses the generation of disinfection by-products.

Raw water is supplied to a membrane filter through a chlorine contact pond. In the Hyakuya mixing pond, chlorine is injected into the raw water, and the meltable manganese in the raw water is partially oxidized to become manganese dioxide. Then, in the powdered coal adsorption tank, powdered activated carbon is charged and stirred to suppress the production of disinfection by-products, and a coagulant is added to coagulate organic substances to complete the pre- and post-treatments. Supply to.

In the membrane filtration device, the aeration causes the suspended solids (solid components) to flow, increasing the concentration thereof, while maintaining a high microbial content and a high manganese oxide content. In addition, since the aeration is constantly performed, the biological treatment properties of ammonia, manganese, and organic substances are improved.

Since the above-mentioned membrane filtration device can perform aeration, flow, biological treatment, and catalytic oxidation of manganese, it has a function as a manganese contact pond by itself, so that turbidity and microorganisms in the immersion tank can be reduced. Manganese can be removed to a considerable extent in the high water temperature period when the amount can be maintained at a high level, but in the low water temperature period, the action of microorganisms is weakened, so that the removal of manganese is insufficient.

In the present invention, the function of the membrane filtration device as a manganese contact pond is increased by providing a system in which the chlorine oxidation method and the powdered activated carbon injection method are incorporated in the preceding stage of the immersion type membrane filtration treatment method. That is, in the previous stage
By injecting (free chlorine), the efficiency of contact oxidation of suspended manganese components and manganese oxide in the membrane filtration device with soluble manganese is increased, and the removal of manganese is possible even in the low water temperature period when the action of microorganisms becomes weak. You can do it enough.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of a water treatment apparatus for carrying out the water treatment method of the present invention, and FIG. 2 shows a membrane module used in the immersion type membrane filtration apparatus in the apparatus.

The water treatment facility has a sub-mixing tank 1 and a powder in front of a submerged ceramic membrane filtration device (hereinafter referred to as a membrane filtration device) A, which can perform separation and removal of solid components contained in raw water as well as biological treatment at the same time. A chlorine contact tank B composed of a charcoal adsorption tank 7 is provided.

The membrane filtration device A is constructed by submerging water in the membrane dipping tank 20 into
A plurality of membrane modules 21 are vertically stacked and arranged. The membrane module 21 uses a ceramic membrane element (hereinafter referred to as a membrane element) 22 having an external pressure type tubular two-layer structure. A large number of the membrane elements 22 are collected in a header, and the header is provided with a suction pipe 23 communicating with each membrane element 22. The suction pipe of each membrane module 21 is provided.
Reference numeral 23 is connected to a collecting pipe 24 and to a filtered water pipe 25, and the filtered water having permeated through the membrane element 22 is taken out of the tank 20 by applying a pressure difference between the inside and outside of the membrane.
This pressure difference is made by the suction pump 26 provided in the filtered water pipe 25.

Below the stacked membrane modules 21, an air diffuser 27 for aeration and stirring is provided.
Air (or oxygen) is supplied by a blower 28 installed outside the tank 20. Further, an inflow pipe 12 for raw water that has passed through a chlorine contact pond B described later is connected to the upper portion of the tank 20. In addition, a sludge pipe 30 provided with a pump 31 for discharging the accumulated sludge is provided at the bottom of the tank 20.

A disinfection tank 35 and a water purification tank 36 are connected in a subsequent stage of the membrane filtration apparatus A, and the treated water filtered by the membrane filtration apparatus A flows into the disinfection tank 35 from the filtration water pipe 25. After being sterilized, it will be retained in the next water purification tank 36 and will be taken out as purified water from there. Also, disinfection tank 35 or water purification tank
36 and a portion of the filtered water pipe 25 closer to the collecting pipe than the suction pump 26 are connected by a pipe 39 having a backwash pump 38, and a disinfection tank 35
Alternatively, the membrane module 21 can be backwashed with the water in the water purification tank 36.

The chlorine contact tank B is provided with a hypo-admixture tank 1 and a powdered coal adsorption tank 7 connected in series. In the hyposia mixing tank 1,
A first baffle wall 2 having a lower opening on the upstream side and a second baffle wall 3 extending from the tank bottom to a lower surface of the liquid are provided on the downstream side, and an upstream end of the sub-mixing tank 1 The section is provided with a raw water a supply pipe 4 equipped with an opening / closing valve 41 and a hypochlorite (free chlorine) injection means 5. In the next powder coal adsorption tank 7,
An injecting means 8 for the powdered activated carbon and a stirrer 9 for stirring and mixing the raw water flowing in from the sub-mixing tank 1 and the powdered activated carbon.
The raw water from the sub-mixing tank 1 overflows the upper end of the partition wall 6 and flows into the powder coal adsorption tank 7.

A mixing device 10 such as a static mixer or a stirring tank provided with a coagulant ha adding means 11 is provided between the powdered coal adsorption tank 7 and the membrane filtration device A. The organic substances in the raw water that have flowed out of the adsorption tank 5 are aggregated to reduce clogging during membrane filtration. Then, a portion of the supply pipe 4 upstream of the on-off valve 41 is connected to the middle of a pipe line connecting the powder coal adsorption tank 7 and the mixing device 10,
A bypass line 40 having an opening / closing valve 42 is provided.

Raw water that requires treatment flows from the supply pipe 4 into the hyposubmixing tank 1 of the chlorine contact pond B, and by injecting free chlorine, it flows up and down in the tank 1, The manganese dissolved in the water is partially oxidized to be converted to manganese dioxide, and the water containing the generated manganese dioxide, residual chlorine, and soluble manganese flows into the next powdered coal adsorption tank 7. In the powdered coal adsorption tank 7, powdered activated carbon (II) is supplied and mixed and stirred by a stirrer 9. As a result, the organic matter in the raw water can be promptly removed, the production of disinfection by-products can be suppressed, and the soluble organic matter is adsorbed to the powdered activated carbon to facilitate the removal.

As described above, in the chlorine contact pond B, since the powdered activated carbon is injected after the chlorine is added, the contact time between the organic matter, chlorine and bound chlorine can be shortened, and the production of trihalomethane can be suppressed. In addition, chlorine remaining without being consumed and unreacted soluble manganese are rapidly oxidized by catalytic oxidation using manganese oxide concentrated in the membrane dipping tank 20, so that the inside of the membrane of the membrane module 21 is Ingress can be suppressed and membrane fouling can be suppressed. Also,
At high water temperature, stop injection of chlorine and powdered activated carbon,
Or, close the open / close valve 41 and open the open / close valve 42,
Bypass the raw water a through the chlorine contact pond B, and
Further flow into the mixing device 10.

The raw water discharged from the powdered coal adsorption tank 7 then flows into the mixing device 10 and the organic substances are further adsorbed by the addition of the coagulant C to improve the solid-liquid separation property.

Raw water b from the mixing device 10 flows into the next stage membrane filtration device A. The raw water (water to be treated) b that has flowed into the membrane filtration device A flows from the lower side to the upper side of the stacked membrane modules 21 while being agitated by the air diffuser 27, and permeates the filtration membrane of the membrane element 22. Then, solid-liquid separation is performed, and the treated water is taken out from the suction pipe 23 to the collecting pipe 24 and then to the filtered water pipe 25.

The membrane filtration device A is provided by immersing the membrane module 21 equipped with the external pressure type tube-type ceramic membrane element 22 and constantly aeration by the air diffuser 27. Can be kept at a concentration. As a result, at a water temperature above a certain level, biological treatment of manganese and ammonia and adsorption / removal to the suspended matter can be performed, so that the membrane filtration device A can function as a biological treatment tank. Therefore, the manganese contact pond in the conventional method becomes unnecessary.

However, in the low water temperature period, the biological activity of the microorganisms is lowered, so that the treatment function is lowered. Therefore, by providing a contact basin composed of a hypo-mixing tank and a powdered coal adsorption tank in the preceding stage of the membrane filtration device A, the functional deterioration is compensated.

[0025]

[Experimental Example] In order to confirm the effect of the present invention, an experiment was conducted by using the treatment apparatus shown in FIG. Highly polluted raw water (river water) used in this experiment
Table 1 shows the target water quality and normal river water quality.

[0026]

[Table 1]

The experiment was conducted in the middle and high water temperature period (before December) and the low water temperature period.
(After December, raw water temperature was 0.5-4.0 ℃). Regarding the treatability of soluble manganese according to the seasons obtained in this experiment and the treatability of manganese according to the chlorine injection rate, Table 2,
It is shown in FIG. 3 and Table 3.

[0028]

[Table 2]

[0029]

[Table 3]

According to the above experiment, in the low water temperature period, the removal rate of soluble manganese was 87% by pre-chlorine injection,
An average concentration of treated water of 0.008 mg / l was achieved. In contrast,
In the case of only treatment with a membrane filtration device without pre-chlorination, the manganese removal rate is 22% and the average concentration of treated water is 0.055 mg / l, especially in the low water temperature period. This proves that the width is excellent.

Table 4 shows the results of measurement of changes in the amount of trihalomethane produced by hypochlorous injection. As shown in this table, the total value of trihalomethane formation ability of treated water at the time of pre-chlorination was 0.008 to 0.042 mg / l, which was lower than the water quality standard value of 0.1 mg / l.

[0032]

[Table 4]

[0033]

As described above, according to the present invention,
Employs a membrane filtration device that can perform high-concentration turbidity microfiltration,
Immersion type membrane filter equipped with aeration means is combined with chlorine contact tank for chlorine oxidation and adsorption of powdered activated carbon to oxidize ammonia and bring soluble manganese in raw water into contact with chlorine. Since it is sent to the tank for treatment, the membrane filtration device can be made to function as a manganese contact pond, the contact efficiency between suspended manganese components and manganese oxide and soluble manganese is increased, and manganese and ammonia are removed. Will be done well.

Since the soluble manganese can be converted to manganese oxide before it reaches the filtration membrane surface, the infiltration of the soluble manganese into the membrane can be reduced and the membrane fouling can be suppressed. it can. Moreover, since the powdered activated carbon is injected after chlorine is injected, organic substances can be reduced and the production of disinfection by-products can be suppressed.

[Brief description of drawings]

FIG. 1 shows an example of a processing apparatus for carrying out the method of the present invention.

FIG. 2 is a side sectional view showing a membrane module in a membrane filtration device used in the same device.

FIG. 3 is a diagram showing the relationship between water temperature and the removal rate of soluble manganese.

[FIG. 4] (1) and (2) respectively show conventional treatment facilities for manganese-containing water using membrane treatment.

[Explanation of symbols]

A membrane filtration device B chlorine contact pond Primary submixing tank 5 Free chlorine injection means 7 Powdered coal adsorption tank 8 Powdered coal injection means 9 stirrer Mixing equipment 20 membrane immersion tank 21 membrane module 22 Membrane element 23 Suction pipe Filtered water pipe 27 Air diffuser 30 sludge pipe 35 Disinfection tank Water tank

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 9/00 503 C02F 9/00 503A 504 504A 504E B01D 65/08 B01D 65/08 C02F 1/28 C02F 1 / 28 B 1/44 1/44 B 1/76 1/76 Z 3/06 3/06 (72) Inventor Takahito Sugimoto 3-1-3 Nihombashi Muromachi, Chuo-ku, Tokyo Kubota Tokyo Head Office (72) Inventor Yukihiko 3-1-3 Nihonbashi Muromachi, Chuo-ku, Tokyo F-term (reference) Kubota Tokyo headquarters 4D003 AA01 AB02 BA02 EA15 EA24 EA30 4D006 GA07 HA28 JA31Z JA53Z JA71 KA01 KA12 KA31 KA44 KA71 KB12 KB13 KB25 KB30 MA01 MA02 MC03X PA01 PB04 PB05 PB70 4D024 AA02 AA05 AB17 BA02 BB01 BC04 CA06 DB05 DB15 DB21 DB23 4D050 AA02 AB55 BB04 BD02 BD06 CA06 CA08 CA12 CA16 CA17

Claims (4)

[Claims] 1. A membrane sub-mixing tank or a sub-mixing tank in front of a membrane module in which a large number of external pressure type tubular membrane elements are incorporated in a membrane dipping tank and a diffusing means is disposed below the membrane module. A chlorine contact basin with a sub-mixing tank and a powdered coal adsorption tank was set up, and chlorine was added to raw water followed by powdered activated carbon to oxidize soluble manganese in the raw water into manganese dioxide.
A method for treating manganese-containing water, which comprises suppressing the generation of disinfection by-products by injecting chlorine, and then sending this to a membrane filtration device for biological treatment and separation and removal of solid components. 2. The manganese according to claim 1, wherein when the raw water is at a high temperature, the raw water is directly put into the membrane dipping tank, or the injection of chlorine and powdered activated carbon in the hyposubmixing tank is stopped. Method for treating contained water. 3. A membrane module in which a large number of external pressure type tubular membrane elements are incorporated in a membrane dipping tank and a membrane filtration device provided with an air diffusing means below the membrane module are provided in front of free chlorine of raw water. A hypochlorite tank equipped with a pouring means, or a chlorine contact pond consisting of the hypocarburizing tank and a powdered charcoal adsorption tank equipped with a pouring means for powdered activated carbon and a stirrer, and means for supplying this to a membrane filtration device An apparatus for treating manganese-containing water, comprising: 4. When the raw water has a high temperature, pipes and valves for bypassing the chlorine contact pond and directly switching the raw water to the membrane dipping tank, or means for stopping the injection of chlorine and powdered activated carbon in the hyposubmixing tank should be provided. The manganese-containing water treatment device according to claim 3, which is characterized in that.