JP2007144307A - Method and apparatus for treating water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable removal of iron from the ground water such as well water containing iron inexpensively and efficiently. <P>SOLUTION: The method comprises a water intake means for taking the ground water from ground water sources such as a well, an oxygen dissolving means for dissolving oxygen in the ground water taken by the water intake means, a removal means for supplying the ground water dissolving oxygen by the oxygen dissolving means to a filtration tank packed with a filter before iron contained in the ground water turns into water-insoluble iron to remove iron from inside the ground water by carrying out self-catalyst contact filtration in the filtration tank, and a discharge means for discharging treated water removing iron by the removal means into a treated water tank. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water treatment method for removing impurities such as iron, manganese, and organic matter contained in groundwater from groundwater taken from a groundwater source such as a well, and a water treatment apparatus therefor.

  In recent years, it has become widespread to use well water for miscellaneous water other than drinking water and cooking water, that is, toilet water, bath water, washing water, water for irrigation, water for ponds, water for car washing, etc. . Generally, in various facilities such as households, schools, and nursing homes that use water supply, the proportion of miscellaneous water in the total amount of water used is 90% or more. Water volume can be greatly reduced, and water bills can be greatly reduced.

  However, since groundwater such as well water usually contains a large amount of iron and manganese, it is often unsuitable as miscellaneous water as it is. It is used as miscellaneous water after being treated.

As a conventional iron removal method, an air exposure iron method is known. This air-exposed iron method uses ferrous hydroxide (Fe (OH) ₂ ), which has high solubility in water by aeration of the water to be treated such as well water. Instead of (Fe (OH) ₃ ), precipitation is performed, and the precipitated ferric hydroxide is removed by a filtration tank filled with a filter medium to obtain treated water (see Patent Documents 1 and 2).

Further, as a conventional manganese removal method, a filtration method using manganese sand as a filter medium is known. In this manganese sand filtration method, the filter medium sand is coated with manganese dioxide (MnO ₂ ) to form manganese sand, and when water to be treated such as well water is passed through the manganese sand filter medium layer in the presence of chlorine, the filter medium is removed. Since it functions as a catalyst for oxidizing divalent soluble manganese in water to manganese dioxide, manganese can be removed from the water to be treated (see Patent Document 3).
JP-A-6-114385 JP 2002-239565 A Japanese Patent Laid-Open No. 2002-35576

  However, iron removal by the above conventional air-exposed iron method changes the iron content dissolved in water to insoluble ferric hydroxide and filters this to obtain treated water. The filtration tank constituted by filling the filter plate was severely clogged, and the filter medium had to be frequently washed, resulting in a reduction in processing efficiency.

  In addition, it has been proposed to oxidize ferrous hydroxide in the treated water to ferric hydroxide by adding a chlorine agent to the treated water without being exposed to air. Since insoluble ferric hydroxide must be removed using a filtration tank, it has the problem that the filter medium must be washed frequently as in the case of the above-mentioned air-exposed iron method. In addition, there is a drawback in that it requires a medicine and a medicine injection device therefor, and the cost is increased.

  Furthermore, methods for removing iron from the water to be treated include iron bacteria methods using iron bacteria, electrolysis methods using electrolysis, ion exchange methods using ion exchange resins, and masking methods that contain iron in an ionic state. It has been known. However, none of these treatment methods has been adopted as means for treating groundwater such as well water so as to be suitable for miscellaneous water from the viewpoint of treatment costs.

  Therefore, the present invention uses a filtration tank filled with a filter medium in the same manner as the conventional air-exposed iron method, but does not need to be washed as frequently as the conventional filtration tank, and silica in the water to be treated. Iron removal is possible at most, and no chemicals or chemical injection devices are required, and iron can be removed from water at low cost without the need for chemicals as in the conventional chlorine oxidation method. It aims at providing the water treatment method and its processing apparatus.

In order to achieve the above object, the water treatment method according to the present invention is characterized in that the invention described in claim 1 dissolves oxygen in groundwater taken from a groundwater source such as a well, so that iron contained in the groundwater is insoluble. Before changing to the iron content, it is supplied to a filtration tank filled with a filter medium, and autocatalytic contact filtration is performed in the filtration tank to remove iron from the groundwater.
The water treatment method according to claim 2 of the present invention is characterized in that in addition to removing iron from groundwater using a filtration tank, other impurities such as manganese and organic matter are also removed.
The water treatment method according to claim 3 of the present invention is characterized in that the dissolution of oxygen in groundwater is performed by sucking air using a venturi pipe while supplying the groundwater to the filtration tank.
The water treatment method according to claim 4 of the present invention is characterized in that the filter medium filled in the filtration tank comprises a gravel layer and a sand layer laminated on the gravel layer.
The water treatment method according to claim 5 of the present invention is characterized in that the sand layer is made of dredged sand.

In order to achieve the above object, the water treatment apparatus according to the present invention is characterized in that the invention described in claim 6 includes a water intake means for taking ground water from a ground water source such as a well, and oxygen in the ground water taken by the water intake means. The oxygen dissolving means for dissolving the oxygen and the groundwater in which oxygen is dissolved by the oxygen dissolving means are supplied to the filtration tank filled with the filter medium before the iron content in the ground water is changed to insoluble iron, and the It is characterized by comprising removing means for performing catalytic contact filtration to remove iron from the ground water and discharging means for discharging treated water from which iron has been removed by the removing means to a treated water tank.
The water treatment apparatus according to claim 7 of the present invention is characterized by removing other impurities such as manganese and organic matter in addition to removing iron from groundwater using a filtration tank.
In the water treatment apparatus according to claim 8 of the present invention, the treated water discharged to the treated water tank is discharged via a water storage tank that stores a predetermined amount of washing water for backwashing the filter medium of the filter tank. It is characterized by being.
The water treatment apparatus according to claim 9 of the present invention is characterized in that the dissolution of oxygen into groundwater is performed by sucking air using a venturi pipe while supplying the groundwater to the filtration tank.
The water treatment apparatus according to claim 10 of the present invention is characterized in that the filter medium filled in the filtration tank is composed of a gravel layer and a sand layer laminated on the gravel layer.
The water treatment apparatus according to claim 11 of the present invention is characterized in that the sand layer is made of dredged sand.

The water treatment method according to claim 1 of the present invention is a filtration in which oxygen is dissolved in groundwater taken from a groundwater source such as a well and the filter medium is filled before the iron content in the groundwater changes to insoluble iron content. Since it is supplied to the tank and the autocatalyst contact filtration is performed in the filtration tank so as to remove iron from the groundwater, no chemicals are required, so iron removal can be performed at low cost. Since insoluble iron is not trapped in the filtration tank, the filter medium is less clogged, and therefore the frequency of washing (backwashing) of the filtration tank can be reduced.
In the water treatment method according to claim 2 of the present invention, the filtration tank removes iron from groundwater, and also removes other impurities such as manganese and organic matter. Can be obtained.
In the water treatment method according to claim 3 of the present invention, since oxygen is dissolved in the groundwater while the groundwater is being supplied to the filtration tank, air is sucked in using the venturi pipe. Oxygen can be easily dissolved.
In the water treatment method according to claim 4 of the present invention, the filter medium filled in the filter tank is a gravel layer and a sand layer laminated on the gravel layer, so that the filter tank can be easily configured.
In the water treatment method according to claim 5 of the present invention, since the sand layer is made of dredged sand, an autocatalytic contact filtration tank can be easily realized.

The water treatment apparatus according to claim 6 of the present invention includes a water intake means for taking ground water from a ground water source such as a well, an oxygen dissolving means for dissolving oxygen in the ground water taken by the water intake means, and the oxygen dissolving means. The oxygen dissolved in the groundwater is supplied to a filtration tank filled with a filter medium before the iron contained in the groundwater changes to insoluble iron, and autocatalytic contact filtration is performed in the filtration tank to remove iron from the groundwater. Since the removal means for removing and the discharge means for discharging the treated water from which the iron content has been removed by the removal means to the treated water tank, it is possible to perform the iron removal treatment at a low cost because no chemicals are required. Since insoluble iron is not trapped in the filtration tank, the filter medium is less clogged, and therefore the frequency of washing (backwashing) of the filtration tank can be reduced.
In the water treatment apparatus according to claim 7 of the present invention, in addition to removing iron from groundwater using a filtration tank, other impurities such as manganese and organic matter can also be removed. Can be obtained.
In the water treatment device according to claim 8 of the present invention, the treated water discharged to the treated water tank is discharged through a water storage tank that stores a predetermined amount of washing water for backwashing the filter medium of the filter tank. Therefore, it is possible to ensure the washing water for the filter medium.
In the water treatment apparatus according to claim 9 of the present invention, since oxygen is dissolved in groundwater while the groundwater is supplied to the filtration tank, air is sucked in using a venturi pipe. It is possible to dissolve oxygen easily.
In the water treatment apparatus according to claim 10 of the present invention, the filter medium filled in the filter tank is a gravel layer and a sand layer laminated on the gravel layer, so that the filter tank can be configured easily.
In the water treatment apparatus according to claim 11 of the present invention, since the sand layer is made of dredged sand, an autocatalytic contact filtration tank can be easily realized.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a flow sheet showing a schematic configuration of a water treatment apparatus according to an embodiment. In FIG. 1, 1 is a well corresponding to a groundwater source of the present invention. Well water W containing iron corresponding to the groundwater of the invention is stored.

The well water W in the well 1 is configured to be supplied to the upper part of the filtration tank 3 via the pump P ₁ and the raw water pipe 2. The pump P ₁ is shown as a submersible pump in the illustrated example, but may be a normal pump such as a spiral pump installed on the ground. The pump P ₁ is configured to be turned ON / OFF by a controller C described later, and is stopped when the water level of the well water W is lowered to a predetermined lower limit by the water level gauge L ₁ . It is devised to protect the pump P ₁ . For this reason, the detection signal of the water level gauge L ₁ is configured to be input to the controller C.

  In FIG. 1, 4 a is a venturi tube that constitutes the oxygen dissolving means of the present invention, and is provided in the middle of the raw water tube 2 near the filtration tank 3. This venturi tube 2 is the same as the ejector tube, and as shown in FIG. 2, an injection nozzle portion 41 that is narrowed down so that the cross-sectional area of the water passage portion provided on the upstream side gradually decreases. The wide air chamber 42 having a predetermined space volume provided on the downstream side of the injection nozzle portion 41 and the outside provided near the injection nozzle portion 41 in the wide air chamber 42 open to the atmosphere, The inside is composed of a gas inlet 43 that opens into the wide space 42.

Venturi tube 4a having the above structure, when well water W through the pump P ₁ is supplied to the venturi 4a, narrowed by the injection nozzle 41 the water to produce a negative pressure is ejected in the wide Check 42 The generated negative pressure causes the air to be sucked into the wide space 42 through the gas suction port 43. Therefore, the sucked air is rapidly mixed and stirred with water in the wide space 42, and the gas (oxygen) is effectively dissolved in the water (well water W). The oxygen dissolving means may be other types such as a pressurized water type that supplies pressurized water in which air (oxygen) is dissolved to the raw water pipe 2 without using the venturi pipe 4a. However, as described above, when the venturi tube 4a is used, there is a feature that oxygen can be easily dissolved using the moving well water W.

  The filtration tank 3 is composed of a cylindrical container having a predetermined volume of the upper opening. In addition, this filtration tank 3 can also be made into a prismatic shape. A screen (strainer) 31 is provided horizontally on the lower side of the filtration tank 3, and the inside of the filtration tank 3 below the screen 31 is formed in the treated water chamber 32.

  A gravel layer 33 is provided above the screen 31, and a sand layer 34 made of dredged sand is further provided on the gravel layer 33. That is, the filtration tank 3 is provided with a filtration layer composed of two layers of a gravel layer 33 and a sand layer 34 laminated on the gravel layer 33.

  The opening of the screen 31 is determined so that the gravel (small gravel) forming the gravel layer 33 can be blocked. The gravel layer 33 plays a role of supporting the sand layer 34 and also has a function of a biofiltration layer that removes organic substances from the water by microorganisms formed on the surface of the gravel. Therefore, the effective diameter, uniformity coefficient, maximum diameter, and minimum diameter of the gravel forming the gravel layer 33 are determined by the properties of the sand forming the sand layer 34 described later, and the filling amount (usage amount) and filling height. (Lamination height of the gravel layer 33) is determined by the amount of treated water and the amount of organic matter contained in the treated water (well water W).

The properties of the cinnabar sand forming the sand layer 34 can be the same as those used in known rapid filtration or slow filtration, and therefore, the cinnabar has an effective diameter of 0.30 to 0.70 mm. A uniformity coefficient of 2.0 or less, a maximum diameter of 2.0 mm or less, and a minimum diameter of 0.18 mm or more can be used. The filling amount (usage amount) and filling height (stacking height of the sand layer 34) of the dredged sand is determined by the amount of treated water and the amount of iron and manganese contained in the treated water (well water W). It is done. The dredged sand composing the sand layer 34 has a function of autocatalytic contact filtration that removes iron (Fe ²⁺ ) in water by the catalytic action of iron oxyhydroxide (FeOOH · H ₂ O) formed on the surface of the sand. is doing. The sand layer 34 is made of dredged sand, but other filter media such as anthracite and garnet (in the present invention, these anthracites are also included in the filter media) can be used. However, when the filter medium is cinnabar sand, there is a feature that it can be easily obtained at low cost.

In FIG. 1, reference numeral 35 denotes a trough provided in the filtration tank 3 above the sand layer 34, and is used to discharge cleaning wastewater from the tank when backwashing the filtration tank 3 described later. Therefore, the trough 35 is connected to a pipe 36 for discharging the cleaning waste water. Further, the pipe 36, which is connected to the pump P _2, configured so that it can discharge the cleaned wastewater to drainage of drainage or the like via a pump P _2. Incidentally, when the washing waste water with the water level difference without using a pump P ₂ can be discharged to the drainage, the pump P ₂ is omitted.

In FIG. 1, reference numeral 37 denotes a pipe having a valve V ₁ in the middle, one end of which opens at the bottom of the filtration tank 3 and the other end is connected to the pump P ₂ . This pipe 37 is used by opening the valve V ₁ when drainage is necessary for draining after washing and replacing the filter medium of the filter tank 3 described later. Incidentally, the drain is when possible water level difference, the pump P ₂ is omitted.

In FIG. 1, L ₂ is a water level meter for detecting the water level in the filtration tank 3, and the detection signal is input to the controller C. The water level gauge L ₂ has three electrode rods L ₂₁ , L ₂₂ , L ₂₃ (the common electrode is omitted in the figure), and the electrode rod L ₂₁ is the sand layer 34. The electrode bar L ₂₂ is installed so as to detect the water level at the position of the trough 35, and when the treated water is obtained, the water level may be detected by the electrode bar L ₂₁ for some reason. used to adjust the water level at the detection position of the electrode rod L ₂₁ to stop the pump P ₁ when the exceeded significantly. The electrode rod L ₂₃ is provided so as to detect the water level a little than the position of the trough 35, the abnormality when the water level rises above the trough 35 significantly for some reason during backwashing cleaning to be described later The water level can be detected.

The water level when the filtration tank 3 obtains treated water is adjusted to be slightly below the water level of the electrode rod L ₂₁ , that is, approximately the same position as the upper surface (surface) of the sand layer 34, or slightly lower. Yes. That is, the water level in the filtration tank 3 is always adjusted to be substantially the same as or slightly lower than the position of the upper surface of the sand layer 34, and the treated water (well water W) on the sand layer 34 is as much as possible to the atmosphere. The water level is adjusted so that it can always be located in the sand layer 34 without contact. Further, even during the suspension of treatment in the filtration tank 3, the water level in the filtration tank 3 is adjusted so that it can be positioned in the sand layer 34, and the treated water (well water W) in which oxygen is dissolved can be brought into contact with the atmosphere. It has been adjusted to be as limited as possible. As described above, when the water to be treated (well water W) is supplied to the sand layer 34 promptly with less chance of contact with the atmosphere, the iron content in the water to be treated (well water W) in which oxygen is dissolved through the venturi 4a. Can be supplied to the sand layer 34 before it is converted to insoluble iron. Such a water level adjustment is performed by using one electrode rod L ₂₁ , but such a water level adjustment device has been separately proposed by the applicant of the present application, and detailed description thereof will be omitted. Water level detection is performed at predetermined time intervals using the rod L ₂₁ to control the supply of treated water (well water W) to the filtration tank 3 and the discharge amount of treated water from the filtration tank 3. Is done. Incidentally, it is performed the water level adjusted similarly using the water level adjustment single electrode rod L ₃₂ of reservoir 6 to be described later.

In FIG. 1, V ₂ and V ₃ are three-way valves, and one of the three-way valves V ₂ connects the treated water chamber 32 of the filtration tank 3 and the lower part of the water storage tank 6 through pipes 50 and 51. In addition, the other three-way valve V ₃ is connected by a pipe 52 with a pump P ₃ interposed therebetween. Then, the other three-way valve V _3, together with and is connected halfway to the processing water chamber 32 of the filtration tank 3 through a pipe 53 having a venturi tube 4b which is configured similarly to the venturi tube 4a, a pipe 54 It is connected to the upper part of the water storage tank 6 via.

The water storage tank 6 has a vent 61 at the top and a water level meter L ₃ , and the water storage capacity is determined so as to cover a single backwash water for the filtration tank 3. Then, always at any time to allow the backwashing cleaning of the filtration tank 3 is adjusted such that a predetermined water level is maintained by using a water level gauge L _3. That is, the water level meter L ₃ is connected to the controller C, and the detection signal of the water level meter L ₃ is input to the controller C. The water level meter L ₃ has three electrode rods L ₃₁ , L ₃₂ , and L ₃₃ (the common electrode is omitted in the figure). Of these, the electrode rod L ₃₁ is a filter tank. 3 is used to detect that the washing water in the water storage tank 6 has disappeared during the backwashing of the electrode 3, and the electrode rod L ₃₂ is always in the water storage tank 6 (time zone excluding the time of washing the filtration tank 3). , a predetermined amount of washing water is used to adjust the water level to be stored, the electrode rod L ₃₃ is reservoir greatly exceeds the water level of the reservoir water level in the 6 electrode rod L ₃₂ for some reason Used to prevent overflow from 6. The water tank 6 can also be used as a treated water tank 8 to be described later. However, as described above, the provision of the water storage tank 6 has the advantage that the washing water for the filtration tank 3 can be secured at all times.

In FIG. 1, 70 is a pipe with a pump P ₄ interposed in the middle, and connects the lower part of the water storage tank 6 and the upper part of the treated water tank 8. In addition, when the water (treated water) in the water storage tank 6 can be discharged to the treated water tank 8 using the water level difference, the pump P ₄ can be omitted. In this case, the valve is provided for adjusting the discharge amount of water to the position of the pump P _4.

The treated water tank 8 is a water storage tank for various facilities such as a water use facility (not shown) such as a school or a nursing home, and water is supplied from the treated water tank 8 to a water use place via a pump P ₅ and a pipe 90. Is done. Therefore, the capacity of the treated water tank 8 is determined by the amount of miscellaneous water used in various facilities. The treated water tank 8 is covered with a canopy 82 having a vent 81 in order to maintain a sanitary condition. The canopy 82 is provided with two water level gauges L ₄ and L ₅ connected to the controller C.

Of the two water level gauges L ₄ and L ₅ , one water level gauge L ₄ is used to detect whether or not the water level in the treated water tank 8 needs to drive the filtration tank 3 to obtain treated water. used, (in the illustrated example, the lower end position the water level of the shorter of the electrode rod of the water level gauge L ₄₎ upper limit water level in the water level gauge L ₄ when is detected, the process by filtration tank 3 is paused. Further, the other water level meter L ₅ cannot obtain the required amount of treated water from the filtration tank 3 for some reason, and the water level in the treated water tank 8 is below a predetermined level (in the example shown, the longer electrode of the water level meter L ₅ when it is rod lower end position level of), and the valve V ₄ in the open supplemented with water supply from the water supply pipe 82, in the example of the replenishing amount is a predetermined level (shown, shorter electrode rod of water gauge L ₅ when it becomes lower end position level) in the valve V ₄ is closed replenishing water supply of which is configured to be stopped. In the example shown in the figure, the two water level gauges L ₄ and L ₅ are provided in the treated water tank 8, but this may be a single water level gauge. In this case, of course, the number of electrode bars increases.

  The controller C is composed of a programmable controller, so-called PC, mainly composed of a CPU, and is configured so that the entire water treatment apparatus according to the present invention can be driven and controlled according to a predetermined program.

In the water treatment apparatus having the above configuration, when the well water W is supplied to the filtration tank 3 through the pump P ₁ , the raw water pipe 2 and the venturi pipe 4 a, the well water W is included in the well water W in the sand layer 34. The iron content in the well water W is effectively removed by the catalytic action of iron oxyhydroxide that is supplied before the iron content is changed to insoluble iron content and is formed on the surface of the dredged sand constituting the sand layer 34. Further, when this sand layer 34 is used for a long period (for example, 3 months or more), manganese sand is formed, so that manganese in the well water W is also effectively removed. Furthermore, since a biofilm is formed on the surface of the gravel constituting the gravel layer 33 by long-term use, organic substances contained in the well water W are also effectively removed.

Table 1 shows the quality of raw water (well water W) and treated water when the water treatment apparatus according to the present invention is applied to an actual apparatus that obtains 240 m ³ of treated water per day. In addition, the soluble silica of this well water W is 30 mg or more.

Sand 34, treated water obtained through the gravel layer 33 and the screen 31, then received in the processing water chamber 32, conduit 50, three-way valve V _2, the pump P _3, the pipe 52, the three-way valve V ₃ and It is discharged to the water storage tank 6 through the pipe 54. Then, the treated water in the water storage tank 6 is discharged to the treated water tank 8 through the pump P ₄ and the pipe 70, and the treated water in the treated water tank 8 is further connected to a pump P ₅ and the pipe 90 at a water use location (not shown). Is discharged through.

Since the sand layer 34 according to the present invention removes iron from water by autocatalytic contact filtration, it is not necessary to strictly consider clogging of the filtration layer, but it prevents clogging due to contaminants contained in the well water W. Therefore, backwashing is performed periodically using treated water stored in the water storage tank 6, for example, once a day. In this backwash cleaning, treated water (wash water) is supplied into the treated water chamber 32 through the pipe 51, the three-way valve V ₂ , the pump P ₃ , the pipe 52, the three-way valve V ₃ , the venturi pipe 4 b and the pipe 53. Done. Since the cleaning water supplied into the treated water chamber 32 contains gas via the venturi pipe 4b, the mixing and stirring of the sand layer 34 can be performed satisfactorily, and the gravel layer 33 is formed. The excess biofilm can be removed effectively.

The water flow of the backwash washing water supplied to the filtration tank 3 is determined so that the sand layer 34 is mixed and stirred without the gravel layer 33 being disturbed. Washing waste water trough 35, through a pipe 36 and pump P ₂ is discharged to the not shown drainage facilities. After the back washing of the filtration tank 3, the treated water is discarded through the valve V ₁ , the pipe 37 and the pump P ₂ until the inside of the filtration tank 3 is stably obtained and a predetermined treated water quality is obtained. At that time, the treated water is discharged into the water tank 6.

  In addition, in the above-mentioned Example, although the filtration tank 3 was made into the downward flow type, it can also be set as an upward flow type. Moreover, in the above-mentioned Example, although the treated water tank 8 was used for miscellaneous water, if the water quality in this treated water tank 8 satisfies the water quality conditions as drinking water, it can be used as it is as drinking water. Further, when the water quality in the treated water tank 8 does not satisfy the water quality condition as drinking water and the water in the treated water tank 8 needs to be used as drinking water, the water in the treated water tank 8 is sterilized. After the predetermined treatment, it is used as drinking water.

It is a flowchart which shows schematic structure of the water treatment apparatus which concerns on this invention. It is sectional drawing of a venturi pipe.

Explanation of symbols

W Well water (ground water)
P ₁ to P ₅ pump L ₁ ~L ₅ water level indicator V _1, V ₄ valves V _2, V ₃ way valve C controller 1 well (groundwater source)
2 Raw water pipe 3 Filtration tank 31 Screen 32 Treatment water chamber 33 Gravel layer 34 Sand layer 35 Troughs 36, 37, 50, 51, 52, 53, 54, 70, 82 Piping 4a, 4b Venturi pipe 6 Water storage tank 8 Treatment water tank

Claims (11)

  Oxygen is dissolved in groundwater taken from a groundwater source such as a well, and supplied to a filtration tank filled with filter media before the iron content in the groundwater changes to insoluble iron. Autocatalytic contact filtration is performed in the filtration tank. A water treatment method characterized by going to remove iron from the groundwater.   2. The water treatment method according to claim 1, wherein other impurities such as manganese and organic matter are removed in addition to removing iron from groundwater using the filtration tank.   The water treatment method according to claim 1 or 2, wherein the dissolution of oxygen in the groundwater is performed by sucking air using a venturi pipe while supplying the groundwater to the filtration tank. Processing method.   The water treatment method according to any one of claims 1 to 3, wherein the filter medium filled in the filtration tank includes a gravel layer and a sand layer laminated on the gravel layer.   The water treatment method according to claim 4, wherein the sand layer is made of dredged sand. Water intake means for taking groundwater from groundwater sources such as wells;
Oxygen dissolving means for dissolving oxygen in the ground water taken by the water taking means;
The groundwater in which oxygen is dissolved by the oxygen dissolving means is supplied to a filtration tank filled with a filter medium before the iron content in the groundwater is changed to insoluble iron, and the groundwater is subjected to autocatalytic contact filtration in the filtration tank. Removing means for removing iron from the inside;
Discharging means for discharging the treated water from which iron has been removed by the removing means to a treated water tank;
A water treatment apparatus comprising:   7. The water treatment apparatus according to claim 6, wherein other impurities such as manganese and organic matter are removed in addition to removing iron from groundwater using the filtration tank.   The water treatment apparatus according to claim 6 or 7, wherein the treated water discharged to the treated water tank is discharged via a water storage tank that stores a predetermined amount of washing water for backwashing the filter medium of the filter tank. A water treatment apparatus characterized by being a thing.   The water treatment apparatus according to any one of claims 6 to 8, wherein the dissolution of oxygen into the groundwater is performed by sucking air using a venturi pipe while supplying the groundwater to the filtration tank. Water treatment equipment.   The water treatment apparatus according to any one of claims 6 to 9, wherein the filter medium filled in the filtration tank includes a gravel layer and a sand layer laminated on the gravel layer.   The water treatment apparatus according to claim 10, wherein the sand layer is made of dredged sand.

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