JP2003190973A - Method for removing iron and manganese and apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing iron and manganese from water such as city water or industrial water water with a new filtering means as, and also to provide an apparatus using the same. <P>SOLUTION: This apparatus 10 is provided with a filter tank 1, a five-way switch 2, an oxidation device 3 incorporating a pump, a backwash water tank 5, and a control panel. The apparatus removes iron and manganese from water such as underground water, underground flow water and applies sterilization treatment to it. The filtering tank 1 is only one tower where iron and manganese are removed. The filtering tank stores a water collecting strainer and a filtering layer above the water collecting strainer. This filtering layer is formed through sintering clay several times and has a particle having a fine porosity, as a base material, and is composed of filtering material particles which are the base material to which manganese oxide is attached. The filtering particle has a particle diameter of 0.28-0.65 mm, and the water collecting strainer has a scale spacing of 0.15-0.25 mm. The downsizing of the removing apparatus is attained in virtue of this system. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention removes iron and manganese from treated water such as groundwater and underground water to treat the treated water as industrial water (miscellaneous water, industrial water, snowmelt water, construction water, etc.). The present invention relates to a method and apparatus for removing iron and manganese that can be used for drinking water (drinking water, etc.).

[0002]

2. Description of the Related Art Iron in treated water such as groundwater and underground water
Methods for removing manganese include a method of performing coagulation and precipitation while adding an oxidizing agent and a method of using microorganisms such as iron bacteria that takes a relatively long time, but the most commonly used method is the oxidizing atmosphere. In the contact filtration method, an autocatalyst in which iron oxide / manganese oxide is attached to the surface of the filter medium while adding an oxidizing agent for maintaining The contact filtration method utilizes the fact that iron / manganese in the water to be treated has the property of adhering to the solid surface at the beginning of oxidation, and if the adhering manganese oxide itself is in an oxidizing atmosphere, it will be catalytic. This is based on the principle that the inflowing iron and manganese are oxidized to promote oxidation and adhere to the surface of the filter medium to be continuously removed.

FIG. 9 is a partially transparent side view of a filtration tank used in a conventional removal device for removing iron and manganese from water to be treated. The filtration tank has a sprinkler nozzle 15 for supplying the water to be treated inside and a water collecting strainer 16 for collecting the filtered treated water in the lower part, and between them,
A filter layer 14 and supporting gravel layers 17 and 18 composed of filter medium particles having manganese oxide attached thereto are arranged on the surface of the matrix. Such a conventional filtering device requires a gravel layer, and since it has a gravel layer, it is inevitably difficult to reduce the size.

[0004]

If filtration is continuously continued, a limit point that filtration cannot be performed will eventually appear. This is because the iron content is physically filtered so that the filter material filter layer is clogged. With regard to manganese, the manganese oxide attached to the surface of the filter medium continues to attach manganese and becomes enlarged, and eventually it becomes a state where it cannot be adsorbed. When backwashing is performed here, iron oxide, which is an obstacle to physical filtration, is discharged by a flow opposite to the filtration, and clogging is eliminated. On the other hand, the manganese oxide adsorbed and enlarged in manganese is also peeled off the skin in the same manner, and at that time, the original manganese oxide attached to the filter material may be peeled off and discharged. As a result, manganese oxide is reduced and manganese removal is affected. Manganese can complete natural complete oxidation in an atmosphere of pH 10 or higher, and therefore an environment of pH 10 or higher is required for activation / regeneration. In addition, the water used for industrial water, etc., removes iron and manganese by this method,
The conventional removing device (filtering device) has two towers, a filter tower for removing iron and a filter tower for removing manganese, resulting in an increase in size of the removing device.

The present invention has been made under such circumstances, and iron, manganese, etc. are removed from the water to be treated such as groundwater and underground water by a filtration means having a novel structure, and further sterilized. , A method for removing iron and manganese that uses treated water for industrial water (miscellaneous water, industrial water, snowmelt water, construction water, etc.) and tap water (drinking water, etc.) and a small size Provided is an optimized removing device.

[0006]

The present invention provides a method for removing iron, manganese, etc. from water to be treated such as groundwater and underground water, and further sterilization, and a removal apparatus for carrying out this method. The filtration tank provided is only one tower, and is characterized by performing iron removal and manganese removal in this filtration tank. The filtration tank accommodates a water collecting strainer and a filtration layer disposed on the water collection strainer. The filtration layer is formed by sintering clay several times and has particles having a dense porosity as a matrix. The filter material particles have a particle size of 0.2.
8 to 0.65 mm, and the mesh width of the water collecting strainer is 0.1
It is characterized by being 5 to 0.25 mm. The requirements for the filter material differ between the iron removal filter material and the manganese removal filter material (for example, since iron removal is physical filtration, the linear velocity (filtration speed) is slowed, and since manganese removal is adsorption removal, the contact time ( It is necessary to slow down the contact area and filtration rate)
Therefore, it was possible to satisfy both requirements by thoroughly examining the filter medium and limiting the particle size of the filter medium particles. Also,
By using the water collecting strainer having a limited mesh width in the lower portion of the filtration layer in the filtration tank, it becomes possible to eliminate the filter material supporting gravel which is conventionally required and to downsize the tank itself.

Further, in the present invention, since the sterilizing agent is used as the oxidizing agent without using the iron removing flocculating agent, the flocculating device is not required. This is because the ferric hydroxide clusters generated by sodium hypochlorite used as a sterilizing agent are small and passed through with the conventional filter media diameter, but if the particle size as described above is made fine enough Allows for filtration. The filtering layer used in the present invention is composed of particles having a dense porosity obtained by sintering clay several times as a matrix, and manganese oxide is attached to the matrix as a filtering medium particle. For example, a chamotte base material having a dense porosity obtained by firing clay several times is used. Chamotte base material is
It has excellent adhesion to manganese oxide and has an apparent specific gravity of about 1.0, which is suitable for rapid filtration. Such matrix a rotating reactor in a manganese chloride (MnCl ₂ ·
4H ₂ O) and potassium permanganate (KMnO ₄ ) are alternately reacted, this is repeated several times, and finally baking is performed. Reaction of a certain amount of potassium and manganese chloride permanganate, higher oxides of sticky brown - dark brown manganese _{(MnO · Mn 2 O 7,} MnO 2 · H
₂ O) is generated (see formulas (1) and (2)). This oxide is attached to a matrix and sintered to obtain filter medium particles. Na ₂ Z + MnCl ₂ → MnZ + 2NaCl (1) MnZ + 2KMnO ₄ → K ₂ Z / MnO / Mn ₂ O ₇ (2)

The removing device used in the method for removing iron and manganese of the present invention performs not only filtration but also back washing, filtration washing and circulation washing. The back washing removes the accumulated iron content by physical filtration. In the filter washing, an oxidizing agent is added to activate and regenerate the manganese oxide used in the filter layer. Furthermore, by circulating cleaning, P of treated water
The H is set to 10 or more to activate and regenerate the manganese oxide. In the filtration cleaning, in the prior art, there are a method of cleaning with treated water and a method of cleaning with filtered treated water. The former cannot be expected to have a cleaning effect because it is cleaned with water to be treated. The latter requires equipment to store treated water. According to the present invention, since the system is downsized, a small amount of water is required for filter cleaning, and as a result, a cleaning water tank for storing treated water to be used as cleaning water in the system should be installed as necessary. You can In addition, the catalytic function of manganese oxide used in the filter material deteriorates. In order to activate / regenerate the catalytic function, it is necessary to have activated water in the vicinity of PH10.
Therefore, in the present invention, an oxidizer, for example, activated water prepared by mixing sodium hypochlorite into the treated water used as washing water to adjust the pH to around 10 is used, and the activated water is closed and circulated to remove manganese oxide. Activate and regenerate.

Next, the mechanism for removing iron and manganese in the filtration treatment of the present invention will be described. 1. About iron removal In order to remove iron in water, iron is changed to an insoluble oxide, and this is filtered by a filter material (filter layer). Iron is
It is dissolved in the form of iron bicarbonate in alkaline water. And, it is stable in the presence of an appropriate amount of CO ₂ (see formula (3)). Fe (HCO ₃ ) ₂ ← → FeCO ₃ + CO ₂ + H ₂ O (3) When CO ₂ decreases and the equilibrium is broken, the reaction proceeds to the right side of the equation (3) to produce iron carbonate and further hydrolyze. Decomposes to give colorless ferrous hydroxide (Fe (OH) ₂ ) (see equation (4)). FeCO ₃ + H ₂ O → Fe (OH) ₂ + CO ₂ ↑ (4) Ferrous hydroxide is easily oxidized with the mixing of oxygen and time, and its solubility is 0.01 ppm or less, and it is hardly soluble in red rust. Color changes to ferric hydroxide (Fe (OH) ₃ ) ((5)
See formula). 2Fe (OH) ₂ +1/2 O ₂ + H ₂ O → 2Fe (OH) ₃ (5)

The iron content in water is converted to ferric hydroxide by the oxidation reaction of sodium hypochlorite (see formula (6)). 2Fe ²⁺ + NaClO + 5H ₂ O → 2Fe (OH) ₃ + NaCl + 4H ⁺ (6) Since ferric hydroxide oxidized by sodium hypochlorite is insoluble, it is filtered during passage through the filter medium ((( 7)
See formula). Fe (HCO ₃ ) ₂ + NaClO + H ₂ O → 2Fe (OH) ₃ ↓ + NaCl (7) Further, the catalytically oxidized γ-iron oxyhydroxide is adsorbed on the filter medium to remove iron ((8 ) See formula). _{Z-MnO · Mn 2 O 7} + 4Fe (HCO 3) 2 → Z- [Mn 2 O] 3 - [γ-FeOOH] 4 + 8CO 2 + 2H 2 O ··· (8) 2. About manganese removal

A blackish brown manganese dioxide hydrate is produced by the oxidation reaction of the manganese content in water and sodium hypochlorite (see the equation (9)). The dissolved ratio of manganese is far smaller than that of iron, but it is not easily oxidized by air like iron and is easily oxidized by sodium hypochlorite. This is because iron is naturally oxidized at pH 7 or higher, whereas manganese is not completely oxidized unless pH 10 or higher. Mn ²⁺ + NaClO + 2H ₂ O → MnO ₂ · H ₂ O + NaCl + 2H ⁺ (9) Sodium hypochlorite, which is an oxidizer, is continuously injected to catalytically oxidize manganese on the surface of the filter medium and to adsorb it on the filter medium. It is removed (see formula (10)). Z represents a mother body. _{Z- [MnO (OH) 2]} + Mn (HCO 3) 2 + NaOCl → Z- [Mn O (OH) 2] 2 + 2CO 2 + NaCl ··· (10)

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic system diagram of an iron / manganese removing device, FIG. 2 is a flow diagram illustrating a flow of removing iron / manganese using the removing device of FIG. 1, and FIG. 3 is a removing device of FIG. 1 is a schematic system diagram for explaining a flow of filtration using the filter, FIG. 4 is a schematic system diagram for explaining a flow of backwashing using the removing apparatus of FIG. 1, and FIG.
6 is a schematic system diagram illustrating the flow of filtration cleaning using the removing device of FIG. 6, FIG. 6 is a schematic system diagram illustrating the flow of circulation cleaning using the removing device of FIG. 1, and FIG. 7 is the removal shown in FIG. FIG. 8 is a schematic perspective view of the apparatus, and FIG. 8 is a partially transparent side view of a filtration tank used in the removing apparatus of FIG. As shown in FIG. 1 and FIG. 7, an iron / manganese removing device 10 includes a filtration tower 1 for one tower, a five-way switching valve 2, a regulating valve 3, an oxidizing device 4 having an oxidizing pump 4, a backwash water tank 5, and control. It has a board 6. The well water is connected to the removing device 10 as water to be treated 8 by a pipe. Piping I derived from the well
Through the three-way switching valve 9 and the pipes A and G through the removing device 1
It is connected to 0. A filtering / backwashing pump 7 is arranged in the pipe A, and is configured to supply the water to be treated 8 into the removing device 10. The pipe G is connected to the backwash water tank 5.

The filtration tank 1 is connected to a pipe B for supplying the treated water 8 from above, and is connected to a pipe C for supplying treated water obtained by filtering the treated water 8. Five-way switching valve 2
A pipe A, a pipe B, a pipe C, a pipe D and a pipe H are connected to. From the oxidizer 4, the oxidant is supplied to the pipe A through the oxidizer valve. The backwash water tank 5 has, for example, a capacity of 250 liters, and the pipe E
And is configured to be supplied with the treated water, and to be connected to the pipe G so that the treated water stored in the tank is supplied to the pipe A. The pipe E is connected to the pipe D and the pipe F via a branch valve, and the pipe F is configured to supply the treated water to the outside. The control panel 6 adjusts the filtration, back washing, filtration washing, and circulation washing performed inside the removing device so that they can be properly processed. FIG. 8 is a partially transparent side view illustrating the inside of the filtration tank 1. The filtration tank has a sprinkling nozzle 1 for supplying water to be treated to the inside thereof.
2. The lower part has a water collecting strainer 13 for collecting the filtered treated water, and in the meantime, the manganese oxide is composed of particles having dense porosity formed by sintering clay several times. A filter layer 11 composed of filter material particles obtained by affixing the above to the matrix is formed. The particle size of the filter medium particle is 0.28 to
It is 0.65 mm. The width of the catchment strainer is 0.1
It is 5 to 0.25 mm. The cross-sectional area of the filtration tank of this example is, for example, 0.126 m ² , and its throughput is, for example, 2.5 m ³ / hour.

Next, the flow of filtering the water to be treated, which is controlled by the control panel, into treated water will be described with reference to FIGS. 2 and 3. Although FIG. 2 is a diagram showing a system flow for automatically controlling the operation of the removing device, it is a flow diagram for explaining the filtration-backwashing-filtration washing step, and does not include circulation washing. When filtration treatment is performed by this removing device, back washing and filtration washing must be performed as post-treatments, but circulation washing is not necessarily performed. This is not included in the flow shown in FIG. 2 because it is a process that is appropriately performed when the filtration state of the device deteriorates. First, the three-way switching valve 9 is switched to the direction for filtering, and the water to be treated 8 from a well or the like is supplied to the pipe A through the pipe I, and is supplied to the inside of the removing device 10 by the filtration / backwash pump 7. Then, while passing through the pipe A, an oxidizer such as sodium hypochlorite is supplied from the oxidizer 4 to the water to be treated through the oxidizer valve. The water to be treated in the pipe A is supplied to the filtration tank 1 by the pipe B via the five-way switching valve 2 and the filtration process is started. At this time, if the pressure inside the apparatus is high, the water supply pump (filtering / backwashing pump 7) is stopped and the operation standby state is maintained until the pressure reaches a predetermined level. When the predetermined pressure is reached, the water supply pump and the oxidation pump in the oxidation device are started to operate.
When the predetermined time is reached, the filtration process ends and the process proceeds to the back washing process.

As shown in FIG. 8, the water to be treated supplied from the pipe B flows from the water spray nozzle 12 to the filter layer 11, is filtered, and is supplied as treated water to the outside through the water collecting strainer 13. The supplied treated water discharged from the lower part of the filtration tank 1 passes through a route of a pipe C, a five-way switching valve 2, a pipe D, and a branch valve, and from the branch valve to a pipe E connected to the backwash water tank 5 and a treated water outlet. It is supplied to the connected pipe F. In this way, the water to be treated is filtered and supplied as treated water from the treated water outlet to the outside. This treated water is filtered to remove iron and manganese (for example, iron is 0.3
ppm or less and manganese can be 0.05 ppm or less). The filtration speed of the removing device of this embodiment is, for example, 20 m / hour.

Next, the flow of the back washing process will be described with reference to FIGS. The back washing is performed after the filtration process, and is intended to remove the accumulated iron content from the filtration layer by physical filtration. First, the three-way switching valve 9 is operated to supply the treated water in the backwash water tank 5 from the pipe G to the pipe A.
At this time, the oxidizer is not mixed in the treated water in the pipe A. The treated water in the pipe A is made to flow to the five-way switching valve 2 by the operation of the filtration / backwash pump 7, and the five-way switching valve 2 is operated to operate the pipe C.
And is supplied to the filtration tank 1 to start the backwash operation. That is, the back washing is performed for a predetermined time so that the water flows from the lower part of the filtration tank through the water collecting strainer and the filter layer to the pipe B from the upper part. The treated water flowing in the pipe B is discharged to the outside from the drain port through the pipe H by switching the five-way switching valve 2. In the present invention, since only one filtration tank is used, the system can be downsized, and as a result, the amount of water required for backwashing can be reduced.

Next, the flow of the filter cleaning process will be described with reference to FIGS. The filtration washing is performed after the back washing treatment, and its purpose is to introduce an oxidizing agent to activate and regenerate the manganese oxide used in the filtration layer. First, the three-way switching valve 9 is operated to flow the treated water 8 from a well or the like into the pipe A, and the filtration / backwash pump 7 is operated to operate the pipe A.
Send out the water to be treated. At this time, the oxidizer valve is opened in the water to be treated in the pipe A to mix the oxidizer from the oxidizer 6 with the oxidizer pump. The water to be treated in the pipe A is a five-way switching valve 2
Is operated to flow into the pipe B and is supplied to the filtration tank 1 to start the filter cleaning process. That is, the filter cleaning is performed for a predetermined time by allowing the flow from the upper part of the filter tank through the filter layer and the water collecting strainer to the pipe C from the lower part. The treated water flowing in the pipe C is discharged to the outside from the drain port through the pipe H by switching the five-way switching valve 2. The filtration and cleaning speed of the removing apparatus of this embodiment is, for example, 20 m / hour.

Next, the flow of the circulation cleaning process will be described with reference to FIG. The circulation cleaning is performed, for example, after filtration cleaning and then filtration, and after the treated water is stored in the backwash water tank, the pH of the treated water is set to 10 or more to activate and regenerate the manganese oxide. . First, the three-way switching valve 9 is operated to supply the treated water in the backwash water tank 5 from the pipe G to the pipe A. At this time, the oxidizer valve is opened in the treated water of the pipe A to mix the oxidant from the oxidizer 6 by the oxidizer pump. The treated water in the pipe A is made to flow to the five-way switching valve 2 by the operation of the filtration / backwash pump 7, and the five-way switching valve 2 is operated to operate the pipe B.
And is supplied to the filtration tank 1 to start the circulation cleaning operation. That is, the pipe C is made to flow from the upper part of the filtration tank through the filtration layer and the water collecting strainer.
The treated water of (1) is supplied to the backwash water tank 4 by operating the five-way switching valve 2. In this way, the circulation cleaning is performed for a predetermined time.

The manganese oxide used in the filter medium is
Its catalytic function deteriorates. In order to activate / regenerate the catalytic function, the presence of treated water having a pH of 10 or more is required. Therefore, in this way, the activated water is prepared by mixing an oxidizing agent such as sodium hypochlorite into the treated water used as the washing water and adjusting the pH to 10 or higher, and activating and regenerating the manganese oxide by closing and circulating the activated water. To do.

[0020]

EFFECTS OF THE INVENTION By removing iron and manganese from treated water such as groundwater and underground water with a single-column filtration tank, the downsizing of the device can be achieved, and therefore households and small-scale businesses that could not be installed in the past can be achieved. It is now possible to use groundwater in places.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of an iron / manganese removing apparatus of the present invention.

FIG. 2 is a flow chart illustrating a flow of removing iron / manganese using the removing apparatus of FIG.

FIG. 3 is a schematic system diagram illustrating a flow of filtration using the removing apparatus of FIG.

FIG. 4 is a schematic system diagram illustrating a flow of backwashing using the removing apparatus of FIG.

5 is a schematic system diagram illustrating a flow of filtration cleaning using the removing apparatus of FIG.

FIG. 6 is a schematic system diagram illustrating a flow of circulation cleaning using the removing apparatus of FIG.

FIG. 7 is a schematic view of the removing device of FIG. 1.

8 is a partially transparent side view of a filtration tank according to the present invention used in the removing apparatus of FIG.

FIG. 9 is a partially transparent side view of a filtration tank used in a conventional removal device.

[Explanation of symbols]

1 ... Filtration tank, 2 ... 5-way switching valve, 3
... Regulator valve, 4 ... Oxidation device, 5 ... Backwash water tank, 6 ... Control panel, 11, 14 ... Filtration layer, 12, 15 ... Sprinkling nozzle, 13, 1
6 ... Water collecting strainer, 17, 18 ... Supporting gravel layer.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/28 C02F 1/28 EF term (reference) 4D019 AA03 BA05 BA07 BB12 BC05 CB02 4D024 AA01 AB16 BA01 BB01 BC01 CA01 DA07 DB02 DB03 DB23 4D050 AA02 AB55 BB06 BD06 CA13 CA15 4G002 AA06 AC03 4G048 AA02 AB08 AE01

Claims (6)

[Claims] 1. A step of adding an oxidizer to water to be treated, and a filter medium particle in which a fine porous particle formed by sintering clay several times is used as a matrix and manganese oxide is attached to the matrix. A step of passing the water to be treated through a filtration tank containing the filtered layer and the water collecting strainer to remove iron and manganese contained in the water to be treated, and the particle diameter of the filter medium is 0.28. The iron / manganese removing method is characterized in that the water collecting strainer has a mesh width of 0.15 to 0.25 mm. 2. In the step of taking out the treated water from a normally used outlet, the treated water is branched and stored as backwash water in a backwash water tank, and the treated water is filtered from the backwash water tank. The method further comprises a step of backwashing the inside of the tank, and a step of supplying an oxidizing agent to the water to be treated and performing filter washing to activate and regenerate the manganese oxide after the backwashing. Item 1. The method for removing iron and manganese according to Item 1. 3. A step of supplying activated water obtained by adding an oxidant to the treated water stored in the backwash water tank and adjusting the pH to 10 or more into the filtration tank to reactivate the manganese oxide. The method for removing iron and manganese according to claim 2, further comprising: 4. An oxidizing device for supplying an oxidizing agent to be added to the water to be treated, a filtration tank, and a storage tank housed in the filtration tank,
A particle having fine porosity obtained by sintering clay several times as a matrix, and a filter layer composed of filter material particles in which manganese oxide is affixed to the matrix, and stored in the filter tank,
A water collecting strainer for collecting treated water that has passed through the filter layer, wherein the filter medium particle diameter is 0.28 to 0.65 mm.
The mesh width of the water collecting strainer is 0.15 to 0.
Iron / manganese removing device characterized by 25 mm. 5. The apparatus further comprises means for branching the treated water taken out from the filtration tank and storing it in the backwash water tank as backwash water, and using the treated water from the backwash water tank to reverse the inside of the filtration tank. The iron / manganese removing device according to claim 4, wherein after the washing and the back washing, an oxidizing agent is supplied to the water to be treated to carry out filtration washing to activate and regenerate the manganese oxide. 6. The PH1 is obtained by adding the oxidant from an oxidizer that supplies the oxidant to the treated water stored in the backwash water tank.
The iron / manganese removing apparatus according to claim 5, wherein activated water adjusted to 0 or more is supplied into the filtration tank to activate and regenerate the manganese oxide.