JP2007061809A - Method for purifying ground water and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for purifying ground water wherein the section for iron removal is separated from the section for manganese removal so as to provide a dissolved oxygen content suitable for microorganism activity. <P>SOLUTION: The inside of a tubular filter column 1 is so partitioned as to form a first channel 4 for an ascending flow and a second channel 5 for a descending flow which communicates with the first channel 4 at the top thereof. The first channel 4 is filled with a filter material for the iron removal 2, while the second channel 5 with a filter material for the manganese removal 3. The first channel 4 has an inlet for raw water 6 and an inlet for oxygen or water to which oxygen is dissolved 7 below the filter material for the iron removal 2, and has an inlet for minute bubbles and oxygen or water to which oxygen is dissolved 8 above the filter material for the iron removal 2. A floss outlet 9 for discharging the floss is disposed above the portion where the first channel 4 communicates with the second channel 5, which has an outlet for treated water 10 below the filter material for the manganese removal 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for purifying groundwater, and in particular, separates an iron removal portion and a manganese removal portion, and in each portion, a dissolved oxygen concentration suitable for the activity of each microorganism is given. The present invention relates to a purification method and an apparatus therefor.

There are cases where iron, manganese, ammonia nitrogen, etc. are dissolved in groundwater such as well water.
In conventional groundwater purification equipment, attempts have been made to remove the above substances by chlorination. However, it is difficult to control the injection of chlorinating agents, and even if these substances are removed, the "chlorine odor due to too high residual chlorine concentration. In addition, the generation of harmful by-products due to the reaction of chlorine with organic compounds in groundwater is becoming increasingly unacceptable to society, resulting in the abandonment of many intake wells as groundwater sources.

Under such circumstances, as a groundwater purification device that may be accepted in the future, there is a groundwater purification device that removes iron, manganese, and ammonia nitrogen using bacteria that live in the ground.
In this groundwater purification device, the only thing that can be used as a chemical is that of phosphate level for activating microorganisms (except for chlorination agents for legal sterilization).

By the way, in such a groundwater purification apparatus, it is a common method for removing Fe, Mn, and NH ⁴⁺ by microorganisms in the process of causing microorganisms to act on the raw water. Manganese bacteria have different concentrations of dissolved oxygen, and conventional purification devices carry these bacteria together in a single filtration tower formed in a cylindrical shape, making it difficult to control dissolved oxygen suitable for each bacterial group. Met.

  In view of the problems of the above-described conventional groundwater purification apparatus, the present invention separates the iron removal portion and the manganese removal portion to provide a dissolved oxygen concentration suitable for the activity of microorganisms. It is an object to provide a method and apparatus.

  In order to achieve the above object, the groundwater purification method according to the first aspect of the present invention supplies oxygen or oxygen-dissolved water as primary DO to the first flow path in which the filter medium for iron removal is disposed, After supplying dissolved oxygen at a concentration necessary for the iron removal treatment, oxygen or oxygen-dissolved water is supplied as secondary DO to the second flow path in which the manganese removal filter medium is disposed. It is characterized by supplying dissolved oxygen at a concentration required for manganese removal treatment.

  And the groundwater purification apparatus of this invention for enforcing this groundwater purification method divides the inside of a cylindrical filtration processing tower, forms the 1st flow path which forms an upward flow, and this 1st flow And a second flow path that forms a downward flow in communication with the upper path, and a filter medium for removing iron is disposed in the first flow path, and a filter medium for removing manganese is disposed in the second flow path. In addition, a raw water introduction part and a water introduction part in which oxygen or oxygen is dissolved are provided under the filter material for removing iron in the first flow path, and water and fine bubbles in which oxygen or oxygen is dissolved on the filter medium for removing iron An introduction part is provided, a floss discharge part for discharging floss is provided above the communication part of the first flow path and the second flow path, and a treated water lead-out part is provided under the filter material for removing manganese in the second flow path. It is characterized by that.

  Similarly, the groundwater purification apparatus of the present invention for carrying out this method for purifying groundwater partitions the inside of a cylindrical filtration tower and forms a downward flow, A first flow path and a second flow path that communicates with each other through the connection flow path to form a downward flow are formed, and a filter medium for iron removal is disposed in the first flow path, and the second flow path is removed. A water introduction part in which a raw material introduction part and a water introduction part in which oxygen or oxygen is dissolved are provided in the first flow path, and oxygen or oxygen is dissolved in the start end part of the connection flow path, with the manganese filter medium disposed Is characterized in that a gas-liquid separation part is provided at the terminal part and a treatment water outlet part is provided under the manganese removal filter medium in the second flow path.

  In this case, the iron-removing filter medium carrying iron-removing bacteria can be used as the iron-removing filter medium.

  Further, a manganese removal filter medium carrying manganese removal bacteria can be used as the manganese removal filter medium.

  Furthermore, the groundwater purification apparatus according to the second aspect of the present invention partitions the inside of the cylindrical filtration tower, forms a upward flow, and communicates with the first flow path at the upper part. A second flow path forming a counter flow, a plate constituting a slow stirring mechanism is disposed in the first flow path, a filter medium is disposed in the second flow path, and raw water is disposed in the first flow path. An introduction part and a potassium permanganate solution introduction part are provided, a bubble introduction part for generating fine bubbles is provided on the slow stirring mechanism, and a floss is provided on the communication part of the first channel and the second channel. A floss discharge part for discharging is provided, and a discharge part for treated water is provided under the filter medium of the second flow path.

  According to the groundwater purification method and apparatus of the first aspect of the present invention, the removed portion of iron and the removed portion of manganese can be separated to give a dissolved oxygen concentration suitable for the activity of microorganisms. In addition to enhancing the activity, the bacteria can be segregated in the filter medium and the purification efficiency can be improved.

  In addition, by using a filter medium for removing iron that supports iron-removing bacteria as a filter medium for removing iron, or by using a filter medium for removing manganese that supports manganese-removing bacteria as a filter medium for removing manganese, The removal of iron and the removal of manganese can be performed by microorganisms.

  Further, according to the groundwater purification apparatus of the second invention, an apparatus having substantially the same structure as that of the groundwater purification apparatus of the first invention is used, when the concentration of iron or manganese is extremely high, or the number of iron bacteria or manganese bacteria. Even in the case of an emergency in which it is impossible to wait for the increase of iron, the removal of iron and removal of manganese can be performed reliably.

  Embodiments of the groundwater purification method and apparatus according to the present invention will be described below with reference to the drawings.

1 to 2 show a first embodiment of the groundwater purification apparatus of the present invention.
This groundwater purification apparatus divides the inside of the cylindrical filtration tower 1 and forms a first flow path 4 that forms an upward flow, and communicates with the first flow path 4 at the upper portion to generate a downward flow. And the second flow path 5 to be formed, the first flow path 4 is provided with the iron removal filter medium 2 carrying the iron removal bacteria, and the second flow path 5 is loaded with the manganese removal bacteria. 3, a raw water introduction part 6 and a water introduction part 7 in which oxygen or oxygen is dissolved are provided below the iron removal filter medium 2 in the first flow path 4. Oxygen or water in which oxygen is dissolved and a fine bubble introduction portion 8 are provided, and a floss discharge portion 9 for discharging floss is provided on the communication portion between the first flow path 4 and the second flow path 5, and the second flow path The treated water outlet 10 is provided under the filter medium 3 for removing manganese.

The filtration treatment tower 1 includes a vertically disposed bottomed outer cylinder 11 and a bottomed inner cylinder 12 disposed concentrically within the outer cylinder 11, and the inside of the inner cylinder 12 has a first flow path. 4. The second flow path 5 is defined between the outer cylinder 11 and the inner cylinder 12.
The outer cylinder 11 is formed with a communication portion with the inner cylinder 12 by making the upper part higher than the inner cylinder 12, and by installing a frustoconical hopper 13 on the upper part, A floss discharge part 9 for discharging one group of floss by overflow is formed.

The first flow path 4 is provided with an iron removal filter medium 2 on which iron-removing bacteria propagate, and the second flow path 5 is provided with a manganese removal filter medium 3 on which manganese removal bacteria propagate.
These are aimed at downsizing of the device, and are supplemented with dissolved oxygen at a concentration suitable for each bacterial group, and integrated with the iron hydroxide lump which may be an obstacle to the filter medium 3 for removing manganese. It is for effectively removing the iron-removing bacteria.

Next, the effect | action of the purification apparatus of the groundwater of a present Example is demonstrated.
When following each treatment process along the flow of raw water, groundwater pumped up from the intake well first flows in the tangential direction from the raw water introduction part 6 at the lower end of the inner cylinder 12 to the inner cylinder 12, An in-cylinder swirl flow is formed.
Further, water in which oxygen is dissolved in the dissolution tank of the gas dissolution tower 14 shown in FIG. 3 (in this case, oxygen (or air) can also be used) is supplied from the water introduction section 7 in which oxygen or oxygen is dissolved. The primary DO is injected into the inner cylinder 12 from the primary DO nozzle 15 as a primary DO, and dissolved oxygen having a concentration necessary for oxidizing Fe ²⁺ in the raw water is supplied.

The raw water supplied with dissolved oxygen immediately passes through the iron removal filter medium 2 on which iron removal bacteria are propagated in an upward flow.
In this process, Fe ²⁺ is solidified as a ferric hydroxide layer on the outside of the iron-removing bacteria and removed from the water. At the same time, the iron-removing filter medium 2 which is a bacterial support constantly moves slowly by upward flow. Therefore, the surplus ferric hydroxide layer on the surface of the filter medium 2 for removing iron is rubbed, and the surplus ferric hydroxide strips are discharged upward. As a result, the contact between the raw water and the iron-removing bacteria is well maintained.

As the inner cylinder 12 is further raised, these pieces of ferric hydroxide reach the oxygen or water in which oxygen is dissolved and the fine bubble introduction part 8 equipped with the decompression nozzle (secondary DO nozzle) 16. To do.
In this case, fine bubbles having a diameter of several tens of microns discharged from the decompression nozzle (secondary DO nozzle) 16 and these pieces are combined, and as shown in FIG. Head towards the top of the water.
In this case, water in which oxygen is dissolved in the dissolution tank of the gas dissolution tower 14 shown in FIG. 3 (in this case, oxygen (or air) can also be used) is dissolved as oxygen or oxygen as secondary DO. From water and the fine bubble introduction part 8, it inject | pours into the inner cylinder 12 via the pressure reduction nozzle (secondary DO nozzle) 16, and supplies the dissolved oxygen of the density | concentration required for the manganese removal process in raw | natural water.
A large number of bubbles reaching the water surface and the ferric hydroxide strips form a floss and are removed from the water by any of the following operations.
In this case, a flocculant can be promoted by adding a flocculant such as polyaluminum chloride (PAC) at an appropriate position of the inner cylinder 12.
Operation 1: Scrape off the floss from the top of the processing tower with a scraper, such as a special scraper.
Operation 2: The froth discharge shutoff valve 17 provided in the treated water outlet 10 is closed, the water level in the treatment tower is raised, and the froth layer accumulated on the water surface is drained out of the treatment tower.
In this case, operation 1 and operation 2 may be used together.
Air bubbles in the filter layer are generated by increasing the diameter of air, oxygen and nitrogen dissolved in water as DO or DN in the manganese removal filter medium 3 and preventing normal filtration. However, by the above operation, the bubbles confined in the filter layer by the downward flow velocity are removed upward due to buoyancy, and the normal filtration rate can be maintained.

As described above, excess iron hydroxide is almost removed, but at the same time, dissolved oxygen is brought into the water as secondary DO from the fine bubbles.
By bringing oxygen into the water from the fine bubbles, the dissolved oxygen concentration in the water in the reversal flow of the communicating portion will be higher than in the iron removal portion.
This is a convenient condition for the next step, manganese removal treatment, and the manganese removal function of the manganese removal bacteria is enhanced.
In this case, if the dissolved oxygen concentration exceeds a certain limit, it becomes an unfavorable condition for the activity and growth of iron-removing bacteria, but by giving a dissolved oxygen concentration suitable for the activity of each microorganism in each part, the result Thus, bacteria can be segregated in each filter medium.

The filter medium 2 for removing iron is back-washed by supplying backwash water or backwash air from the backwash tubes 20 and 21 to remove trapping substances, excess bacteria, iron oxide, and the like in the upper portion of the inner cylinder 12. It is possible to flow out of the filtration processing tower 1 from the floss discharge part 9 through the sludge pipe 22.
Further, the filter medium 3 for removing manganese is back-washed by supplying backwash water from the backwash pipe 18 of the treated water outlet 10 to remove trapping substances, excess bacteria, manganese oxide, and the like on the upper portion of the outer cylinder 11. The drainage pipe 19 can flow out of the filtration tower 1.

Thus, a small portion of the intermediate treated water rich in DO flows out with the removal of the froth, but most of the water is inverted as shown in the figure and passes through the filter medium 3 for removing manganese. go.
The upper part of the filter medium 3 for manganese removal is composed of a relatively coarse filter medium such as granular activated carbon, and the lower part is composed of silica sand and a supporting gravel layer. It has come to fulfill.
If necessary, a conventional quick filter dedicated to turbidity may be installed as a separate body.
The removal of ammoniacal nitrogen can be performed with the manganese removal filter medium 3, and the removal of ammonia can also be performed with the iron removal filter medium 2.

  Thus, according to the groundwater purification apparatus of the present embodiment, the filter medium 2 for removing iron that carries iron-removing bacteria and the filter medium 3 for removing manganese that carries manganese-removing bacteria are provided inside the cylindrical filtration tower 1. In the groundwater purification apparatus provided with the first flow path 4 that partitions the inside of the filtration treatment tower 1 and forms an upward flow, and the first flow path 4 communicates with the upper portion of the first flow path 4 to generate the downward flow. The second flow path 5 to be formed is formed, the filter medium 2 for removing iron is disposed in the first flow path 4, the filter medium 3 for removing manganese is disposed in the second flow path 5, and the first flow path 4 A raw water introduction part 6 and a water introduction part 7 in which oxygen or oxygen is dissolved are provided under the iron removal filter medium 2, and water and fine bubble introduction part in which oxygen or oxygen is dissolved on the iron removal filter medium 2 8 and a floss discharge part 9 for discharging the floss on the communication part of the first flow path 4 and the second flow path 5 is provided. Since the treated water lead-out section 10 is provided under the filter medium 3 for iron, the removed portion of iron and the removed portion of manganese are separated, and in each portion, a dissolved oxygen concentration suitable for the activity of each microorganism is given. As a result, the activity of each bacterium can be increased, and the bacteria can be segregated in each filter medium, thereby improving the purification efficiency.

By the way, in the groundwater purification apparatus of the first embodiment, the manganese removal filter medium 3 carrying manganese removal bacteria is used for the manganese removal treatment in the raw water. As shown in the chart of the second embodiment of the apparatus, the manganese removal treatment can be performed using a high performance filter medium for manganese removal.
Manganese sand can be suitably used for the filter medium for removing manganese, and in particular, a ceramic that is used as a base material and can increase the amount of MnO ₂ attached can be more suitably used. .
Thereby, advanced manganese removal treatment can be performed in a compact space.
In addition, since the current water law requires chlorination for sterilization, it is not a problem even if manganese removal treatment with manganese sand is performed on water that has been removed of iron and ammonia nitrogen. Nor. Furthermore, there is no need for turbidity, post-aggregation for sterilization, and subsequent separate sand filtration that may be necessary when the manganese removal treatment is a bacterial treatment (the groundwater in this second embodiment). There is an advantage that high-level treated water can be obtained only with the purification device).
In addition, the other structure and effect | action of a present Example are the same as that of the purification apparatus of the groundwater of the said 1st Example.

Moreover, in the groundwater purification apparatus of the said 1st and 2nd Example, the inside of the cylindrical filtration processing tower 1 is divided, the 1st flow path 4 which forms an upward flow, and this 1st flow path 4 and the second flow path 5 communicating with the upper part to form a downward flow, but as shown in the third embodiment of the groundwater purification apparatus of the present invention in FIG. A first flow path 4 that divides the inside of the filtration tower 1 to form a downward flow, and a second flow path that communicates with the first flow path 4 and the connection flow path 23 to form a downward flow. The flow passage 5 is formed, the first flow passage 4 is provided with the iron removal filter medium 2 carrying the iron removal bacteria, and the second flow passage 5 is provided with the manganese removal filter medium 3 carrying the manganese removal bacteria. In addition, the raw water introduction part 6 and the water introduction part 7 in which oxygen or oxygen is dissolved are provided in the first flow path 4, and oxygen or oxygen is provided at the start end of the connection flow path 23. Water inlet portion 8A dissolved, the gas-liquid separator 24 is provided, and a lead portion 10 of treated water provided beneath the removal of manganese filter material 3 of the second flow path 5 at the end.
Then, as in this embodiment, by forming a downward flow in the first flow path 4, removal of iron when high concentration (for example, 5 mg / L or more) of iron is present in the raw water. Can be efficiently performed, and it is easy to divert the prior art, and there is an advantage that the device can be designed easily.
In addition, the other structure and effect | action of a present Example are the same as that of the purification apparatus of the groundwater of the said 1st Example.

Further, when the iron or manganese concentration is extremely high, instead of the bacterial treatment, treatment with a chemical such as potassium permanganate having a strong oxidizing power against iron or manganese and a very rapid reaction may be performed. In particular, it is a useful technique in emergencies where the number of iron and manganese bacteria cannot be waited for.
Specifically, using the same apparatus as the filtration tower 1 shown in FIGS. 1 to 2 of the first embodiment, instead of the filter medium 2 for removing iron that should be propagated with iron bacteria accommodated in the inner cylinder 12. Incorporating a slow stirring mechanism in the inner cylinder 12 for further growing and increasing the diameter of a floc that is integrated with iron hydroxide and manganese oxide that begins to form after pouring a potassium permanganate solution into the raw water . As an example, several plates that form a diversion are inserted to facilitate the formation of flocs.
Further, instead of oxygen or water containing dissolved oxygen introduced from the water introduction part 7 in which oxygen is dissolved, a potassium permanganate solution is injected, and solidification is performed by oxidation of Fe ²⁺ and Mn ^2+. .
When the reaction with the chemicals injected in the inner cylinder 12 is completed and micro flocs are formed, a flocculant such as polyaluminum chloride (PAC) is added to promote flocking.
At the stage where the floc has sufficiently grown (the upper portion of the inner cylinder 12), the fine bubbles released from the decompression nozzle (secondary DO nozzle) 16 are attached to the floc and discharged out of the system as floss. The remaining ammoniacal nitrogen is removed by injecting a small amount of phosphate into the reverse flow after removing the froth, and nitrifying with bacteria propagated in the filter medium corresponding to the filter medium 3 for removing manganese stored in the outer cylinder 11. be able to.

  As mentioned above, although the purification method and the apparatus of the groundwater of this invention were demonstrated based on the Example, this invention is not limited to the structure described in the said Example, The structure described in the Example is suitably used. The configuration can be changed as appropriate within a range that does not depart from the gist, such as combining.

  The method and apparatus for purifying groundwater according to the present invention have the property of separating the iron removal portion and the manganese removal portion and providing a dissolved oxygen concentration suitable for the activity of each microorganism in each portion. Therefore, for example, it can be suitably used as a high-speed and compact groundwater purification device.

It is a front view which shows 1st Example of the purification apparatus of groundwater of this invention. It is the same front sectional view. It is a chart figure which shows the purification system of groundwater using the purification device. It is a chart figure which shows the purification system of groundwater using the purification device of groundwater of the 2nd example of the present invention. The 3rd Example of the purification apparatus of the groundwater of this invention is shown, (a) is front sectional drawing, (b) is a detailed figure of a gas-liquid separation part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Filtration tower 2 Filter medium for iron removal 3 Filter medium for manganese removal 4 1st flow path 5 2nd flow path 6 Raw water introduction part 7 Water introduction part (primary DO) which dissolved oxygen or oxygen
8 Oxygen or water in which oxygen is dissolved and microbubble introduction part (secondary DO)
8A Oxygen or water-introducing part in which oxygen is dissolved (secondary DO)
DESCRIPTION OF SYMBOLS 9 Floss discharge | emission part 10 Treated water derivation | leading-out part 11 Outer cylinder 12 Inner cylinder 13 Hopper 14 Gas dissolution tower 15 Primary DO nozzle 16 Decompression nozzle (secondary DO nozzle)
17 Floss discharge shut-off valve 18 Backwash pipe 19 Drain pipe 20 Backwash pipe 21 Backwash pipe 22 Drainage pipe 23 Connection flow path 24 Gas-liquid separator

Claims (6)

  After supplying oxygen or oxygen-dissolved water as primary DO to the first flow path in which the filter medium for iron removal is provided, and supplying dissolved oxygen at a concentration required for iron removal treatment in the raw water, manganese removal The second flow path in which the filter medium is disposed is supplied with oxygen or oxygen-dissolved water as secondary DO to supply dissolved oxygen having a concentration necessary for manganese removal treatment in the raw water. Groundwater purification method.   The inside of the cylindrical filtration processing tower is partitioned to form a first flow path that forms an upward flow, and a second flow path that communicates with the first flow path at the top to form a downward flow. The filter medium for removing iron is disposed in the first flow path, the filter medium for removing manganese is disposed in the second flow path, and the raw water introduction part and oxygen or oxygen are placed under the filter medium for removing iron in the first flow path. A water introduction part in which oxygen is dissolved, oxygen or water in which oxygen is dissolved and a fine bubble introduction part are provided on the filter medium for removing iron, and on the communication part between the first channel and the second channel An apparatus for purifying groundwater, comprising a floss discharge part for discharging floss, and a discharge part for treated water provided under the manganese removal filter medium in the second flow path.   A first flow path that divides the inside of the cylindrical filtration tower and forms a downward flow, and a second flow that forms a downward flow in communication with each other via the first flow path and the connection flow path And a filter medium for removing iron in the first flow path, a filter medium for removing manganese in the second flow path, and the raw water introduction part and oxygen or oxygen dissolved in the first flow path. And a water introduction part in which oxygen or oxygen is dissolved at the start end of the connection channel, a gas-liquid separation part at the end, and under the manganese removal filter medium in the second channel. An apparatus for purifying groundwater, wherein a treated water outlet is provided.   4. The apparatus for purifying groundwater according to claim 2, wherein the filter medium for iron removal uses a filter medium for iron removal that carries iron-removing bacteria.   5. The apparatus for purifying groundwater according to claim 2, 3 or 4, wherein the filter medium for removing manganese uses a filter medium for removing manganese which carries manganese-removing bacteria.   The inside of the cylindrical filtration processing tower is partitioned to form a first flow path that forms an upward flow, and a second flow path that communicates with the first flow path at the top to form a downward flow. In addition, a plate constituting a slow stirring mechanism is disposed in the first flow path, a filter medium is disposed in the second flow path, and a raw water introduction part and a potassium permanganate solution introduction part are provided in the first flow path. A bubble introduction part for generating fine bubbles is provided on the slow stirring mechanism, and a floss discharge part for discharging floss is provided on the communication part of the first flow path and the second flow path. An apparatus for purifying groundwater, wherein a treated water outlet is provided under the filter medium.

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