JP6329807B2 - Iron / manganese-containing water treatment apparatus and treatment method - Google Patents

Description

  The present invention relates to a treatment apparatus and treatment method for iron / manganese-containing water containing at least one of iron and manganese.

  River water, groundwater, etc., which are water sources, may contain soluble iron and soluble manganese. As a method for removing soluble iron and soluble manganese in such iron / manganese-containing water, a contact manganese sand filtration method is known. The contact manganese sand filtration method is a method in which soluble manganese is precipitated by oxidation and trapped in manganese sand while raw water is passed through the manganese sand filling tank in a downward flow.

  In addition, as a method of performing high-speed treatment of iron / manganese-containing water, while adding chlorine to raw water, an upward flow of, for example, 1,000 m / day or more is applied to an oxidation treatment tank filled with a manganese oxide catalyst. A method is known in which iron and manganese in raw water are oxidized and precipitated by passing water, and the oxidized precipitate is removed by a subsequent filtration membrane (see, for example, Patent Document 1).

  For example, the conventional iron / manganese-containing water treatment apparatus shown in FIGS. 5 and 6 includes a raw water tank 50, an oxidation treatment tank 52, a membrane filtration device 54, a treatment water tank 56, an oxidant tank 58, and a backwash drainage tank 60. In the iron / manganese-containing water treatment apparatus shown in FIG. 5, the oxidant is added from the oxidant tank 58 to the raw water from the raw water tank 50, and water is passed downward through the oxidation treatment tank 52 filled with manganese sand. . Iron and manganese in the raw water are oxidized and precipitated and captured by manganese sand, and precipitates and suspensions flowing out from the oxidation treatment tank 52 are removed by a membrane filtration device 54 in the subsequent stage. When the membrane of the membrane filtration device 54 needs to be washed, at least a part of the treated water stored in the treated water tank 56 is supplied to the membrane filtration device 54 from the membrane filtrate outlet side, and the filtration membrane is backwashed. Is called. The backwash drainage of the membrane filtration device 54 is stored in the backwash drainage tank 60 and discarded. For cleaning the oxidation treatment tank 52, treated water stored in the treated water tank 56 is used.

  In the iron / manganese-containing water treatment apparatus shown in FIG. 6, manganese oxide is added at an upward flow of, for example, 1,000 m / day or more while adding an oxidizing agent from the oxidizing agent tank 58 to the raw water from the raw water tank 50. Water is passed upward through the oxidation treatment tank 52 filled with the catalyst. The raw water from the raw water tank 50 is used for cleaning the oxidation treatment tank 52. In order to remove deposits on the manganese oxide catalyst during the cleaning of the oxidation treatment tank 52, the linear velocity exceeds the linear velocity during normal operation, for example, as an upward flow at a higher linear velocity of about 2,000 to 3,500 m / day. It is necessary to pass the raw water from the water tank 50.

  The method as shown in FIG. 6 allows the raw water to pass at a higher linear speed than the conventional contact manganese sand filtration method as shown in FIG. Since there is little blockage due to turbidity, the cleaning frequency of the oxidation treatment tank can be reduced.

  However, since raw water is used for cleaning the oxidation treatment tank and the cleaning waste water is discarded, there is a problem that the water recovery rate as a whole decreases. In order not to lower the water recovery rate, it is possible to wash with raw water and pass it through the subsequent membrane filtration device without discarding the washing wastewater, but in that case, washing with high turbidity The wastewater is passed through the membrane all at once, which may promote irreversible clogging of the membrane.

Japanese Patent No. 3786888

  An object of the present invention is to provide a treatment apparatus and a treatment method for iron / manganese-containing water that has a high water recovery rate and can stably operate a membrane filtration apparatus.

The present invention provides an oxidizing agent adding means for adding an oxidizing agent to iron / manganese-containing water containing at least one of iron and manganese, and manganese dioxide for oxidizing the oxidizing agent-added water to which the oxidizing agent is added. An oxidation treatment tank filled with an oxidation catalyst containing, a membrane filtration device for membrane filtration of the oxidized treatment water, backwashing means for backwashing the membrane filtration device, and backwashing for backwashing the membrane filtration device Cleaning means for cleaning the oxidation treatment tank using at least a part of the waste water as washing water, and the washing of the oxidation treatment tank is performed with a washing flux in the range of 1,200 to 3,600 m / day. Ru place in countercurrent, a processing unit of an iron / manganese-containing water.

Moreover, this invention contains manganese dioxide, the oxidizing agent addition process which adds an oxidizing agent to the iron / manganese containing water containing at least 1 among iron and manganese, and the oxidizing agent addition water to which the said oxidizing agent was added An oxidation treatment step of passing water through an oxidation treatment tank filled with an oxidation catalyst to oxidize, a membrane filtration step of passing the oxidized treatment water through a membrane filtration device and performing membrane filtration, and the membrane filtration device a backwashing step of backwashing, seen including and a cleaning step of cleaning the oxidation treatment tank with at least a portion of the backwash waste water backwash the membrane filtration device as washing water, the washing of the oxidation treatment tank Is an iron / manganese-containing water treatment method in which the washing flux is performed in an upward flow in the range of 1,200 to 3,600 m / day .

  In the present invention, by washing the oxidation treatment tank using backwash wastewater obtained by backwashing the membrane filtration device as washing water, the water containing iron / manganese has a high washing water recovery rate and enables stable operation of the membrane filtration device. The processing apparatus and the processing method can be provided.

It is a schematic block diagram which shows an example of the processing apparatus of the iron / manganese containing water which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the processing apparatus of the iron / manganese containing water which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the processing apparatus of the iron / manganese containing water which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the processing apparatus of the iron / manganese containing water which concerns on embodiment of this invention. It is a schematic block diagram which shows an example of the conventional iron / manganese containing water processing apparatus. It is a schematic block diagram which shows the other example of the processing apparatus of the conventional iron / manganese containing water. It is a figure which shows the processing result of Example 1.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  An outline of an example of the iron / manganese-containing water treatment apparatus according to the embodiment of the present invention is shown in FIG. The iron / manganese-containing water treatment device 1 includes an oxidation treatment tank 12 filled with an oxidation catalyst containing manganese dioxide, and a membrane filtration device 14. The iron / manganese-containing water treatment apparatus 1 may include a raw water tank 10 and a treated water tank 16.

  In the iron / manganese-containing water treatment apparatus 1 of FIG. 1, a raw water pipe 26 is connected to the inlet of the raw water tank 10, and the outlet of the raw water tank 10 and the oxidizing agent added water inlet of the oxidation treatment tank 12 are connected via a pump 20. The raw water supply pipe 28 is connected, the outlet of the oxidation treatment tank 12 and the inlet of the membrane filtration device 14 are connected by the oxidation treatment water pipe 30, and the membrane filtrate outlet of the membrane filtration device 14 and the inlet of the treatment water tank 16 are membranes. A treated water pipe 34 is connected to the treated water outlet of the treated water tank 16. Further, the backwash water outlet of the treatment water tank 16 and the middle of the membrane filtration water pipe 32 are connected by a backwash water pipe 38 via the pump 24, and the backwash drainage outlet of the membrane filtration apparatus 14 and the washing of the oxidation treatment tank 12 are performed. The water inlet is connected by a backwash drain pipe 40, and a cleaning drain pipe 42 is connected to the cleaning drain outlet of the oxidation treatment tank 12. The outlet of the oxidant tank 18 is connected to the downstream side of the pump 20 of the raw water supply pipe 28 by an oxidant pipe 36 via the pump 22.

  The operation of the iron / manganese-containing water treatment method and the iron / manganese-containing water treatment apparatus 1 according to the present embodiment will be described.

  Iron / manganese-containing water containing at least one of iron and manganese, which is raw water, is stored in the raw water tank 10 through the raw water pipe 26 as necessary. The iron / manganese-containing water is sent to the oxidation treatment tank 12 through the raw water supply pipe 28 by the pump 20, and in the middle of the raw water supply pipe 28, the oxidant from the oxidant tank 18 passes through the oxidant pipe 36 by the pump 22. / Addition to manganese-containing water (oxidizing agent adding step), and sent to the oxidation treatment tank 12 as oxidizing agent added water. In the present embodiment, the oxidant tank 18, the pump 22, and the oxidant pipe 36 function as oxidant addition means.

  In the oxidation treatment tank 12, the oxidant-added water is passed in an upward flow and is oxidized by an oxidation catalyst containing filled manganese dioxide (oxidation treatment step). While the oxidizing agent is added to the iron / manganese-containing water, water is passed through the oxidation treatment tank 12 filled with the oxidation catalyst containing manganese dioxide, so that dissolved iron and dissolved manganese are oxidized and precipitated.

  Oxidized oxidized water is fed from the outlet of the oxidation treatment tank 12 to the membrane filtration device 14 through the oxidation treated water pipe 30, and the oxidized precipitate is subjected to membrane filtration in the membrane filtration device 14 (membrane). Filtration step).

  The membrane filtrate of the membrane filtration device 14 is sent to the treated water tank 16 through the membrane filtrate pipe 32 and stored. A predetermined amount of treated water stored in the treated water tank 16 is discharged through the treated water pipe 34.

  When it is necessary to clean the membrane of the membrane filtration device 14, at least a part of the treated water stored in the treatment water tank 16 is supplied from the membrane filtration water outlet side to the membrane filtration device 14 through the backwash water pipe 38 by the pump 24. Then, the membrane is backwashed (backwashing step). In the present embodiment, the treated water tank 16, the pump 24, and the backwash water pipe 38 function as backwashing means.

  At least a part of the backwash drainage of the membrane filtration device 14 is supplied from the backwash drainage pipe 40 of the membrane filtration device 14 through the backwash drainage pipe 40 as wash water from the wash water inlet of the oxidation treatment bath 12. In FIG. 2, the cleaning water is passed in an upward flow, and the oxidation treatment tank 12 is cleaned (cleaning process). The remainder of the backwash drainage may be discharged from the middle of the backwash drainage pipe 40. The washing waste water in the oxidation treatment tank 12 is discharged through the washing drain pipe 42.

  In the iron / manganese-containing water treatment apparatus 1 according to the present embodiment, dissolved iron and dissolved manganese are oxidized by passing water through an oxidation catalyst-containing tank containing manganese dioxide while adding an oxidizing agent to the iron / manganese-containing water. In the method of depositing and subjecting the oxidized water to membrane filtration, the backwash waste water of the membrane filtration device 14 is used as the washing water for the oxidation treatment tank 12. In this way, by washing the oxidation treatment tank 12 using at least a part of the backwash waste water that backwashed the membrane filtration device 14 as wash water, the water recovery rate is higher than that of the conventional system, An iron / manganese-containing water treatment apparatus capable of stable operation can be realized.

  The backwash wastewater from the membrane filtration device 14 generally contains about 20 times as much turbidity as the raw water, but the cleaning flux of the oxidation treatment tank 12 is set to about 1,200 to 3,600 m / day. For example, these turbid substances are hardly trapped in the oxidation treatment tank 12 and can be discharged out of the system. Therefore, the cleaning effect is inferior to the case where membrane filtrate water or raw water is used as the cleaning water. There is no.

  When the cleaning flux of the oxidation treatment tank 12 is less than 1,200 m / day, turbidity may be trapped in the oxidation treatment tank 12, and the flow rate exceeding 3,600 m / day is the tank height of the oxidation treatment tank 12. Unrealistic because it gets too high. The cleaning flux of the oxidation treatment tank 12 is more preferably in the range of 1,800 m / day or more and less than 3,000 m / day.

  Moreover, since the washing | cleaning waste_water | drain of the oxidation treatment tank 12 becomes a high density | concentration compared with the backwashing waste_water | drain of the membrane filtration apparatus 14, there also exists an advantage that drainage processing becomes easy. Furthermore, in the operation method described in Patent Document 1, since both the flushing water and the washing of the oxidation treatment tank 12 are performed by the raw water pump, the pump capacity is set to a high head according to the washing, and the flow rate is adjusted. However, in the method of this embodiment, it is not necessary to do so.

  The iron / manganese-containing water to be treated contains at least one of iron and manganese, preferably contains at least manganese, and usually contains both iron and manganese. The content of soluble iron in the iron / manganese-containing water is, for example, in the range of 0.1 to 10 mg / L, and the content of soluble manganese is, for example, in the range of 0.01 to 5 mg / L.

  Examples of the iron / manganese-containing water to be treated include river water, groundwater, lake water, and the like.

  Examples of the oxidizing agent include sodium hypochlorite, bleached powder, potassium permanganate, chlorine dioxide and the like, and sodium hypochlorite is preferable from the viewpoint of running cost, versatility and the like.

  The amount of oxidant added is, for example, in the range of 0.5 mol to 2 mol with respect to 1 mol of iron for soluble iron in iron / manganese-containing water, The range is from 1 mol to 4 mol with respect to 1 mol of manganese content. If the addition amount of the oxidizing agent is less than the above value, the reaction may be insufficient. If it is excessively added, the cost may be disadvantageous and the amount of trihalomethane generated may increase.

  Examples of the oxidation catalyst containing manganese dioxide include an oxidation catalyst in which manganese dioxide is granular and solid, manganese sand, and the like. Further, the manganese dioxide is not particularly limited, and examples thereof include manganese dioxide having α-type, β-type, ε-type, γ-type, λ-type, δ-type, and R-type crystal structures. From this point, manganese dioxide having a β-type crystal structure is preferable.

The density of the oxidation catalyst containing manganese dioxide is preferably 2.8 g / cm ³ or more. When the density of the oxidation catalyst containing manganese dioxide is less than 2.8 g / cm ³ , the catalyst develops when water is passed at high speed, and the tank height of the oxidation treatment tank 12 may increase.

  The particle diameter of the oxidation catalyst containing manganese dioxide is preferably in the range of 0.4 mm to 2.0 mm. If the particle size of the oxidation catalyst containing manganese dioxide is less than 0.4 mm, the rate of expansion of the catalyst may increase, and particles having a small particle size may flow out. Efficiency may be reduced.

  The water flow velocity by the upward flow in the oxidation treatment tank 12 is, for example, a high linear velocity in the range of 1,000 m / day to 3,600 m / day, and in the range of 1,200 m / day to 2,400 m / day. Preferably there is. If the water flow rate due to the upward flow in the oxidation treatment tank 12 is less than 1,000 m / day, the catalyst may not flow substantially uniformly, and a single flow may occur. If it exceeds 3,600 m / day, There are cases where the expansion rate is increased and the tank height of the oxidation treatment tank 12 is increased.

  The reaction temperature in the oxidation treatment tank 12 is, for example, in the range of 1 ° C to 50 ° C.

  The filtration membrane used in the membrane filtration device 14 is not particularly limited as long as it can filter the precipitate that has been oxidized and precipitated, and examples thereof include a UF membrane and an MF membrane. A UF membrane is preferable from the viewpoint that fine manganese particles (for example, less than 0.1 μm) and the like that have been peeled can be removed.

  FIG. 2 shows an outline of another example of the iron / manganese-containing water treatment apparatus according to this embodiment. The iron / manganese-containing water treatment device 3 has a backwash drainage tank 44 installed in the middle of the backwash drainage pipe 40, and a pump 46 installed in the middle of the backwash drainage pipe 40 on the outlet side of the backwash drainage tank 44. Except for this, it is the same structure as the iron / manganese containing water treatment apparatus 1 of FIG.

  In the iron / manganese-containing water treatment device 3 of FIG. 2, at least part of the backwash drainage of the membrane filtration device 14 is stored in the backwash drainage tank 44 through the backwash drainage pipe 40 from the backwash drainage outlet of the membrane filtration device 14. Is done. At least a part of the backwash drainage stored in the backwash drain 44 is supplied as wash water from the wash water inlet of the oxidation treatment tank 12, and the wash water is passed upward in the oxidation treatment tank 12 to oxidize. The processing tank 12 is cleaned (cleaning process). The washing waste water in the oxidation treatment tank 12 is discharged through the washing drain pipe 42.

  The iron / manganese-containing water treatment apparatus 1 shown in FIG. 1 is advantageous in that it is a more compact system than the iron / manganese-containing water treatment apparatus 3 shown in FIG. 2, and the pump 46 is unnecessary. This is advantageous in terms of equipment cost and running cost. On the other hand, in the iron / manganese-containing water treatment device 3 shown in FIG. 2, since the backwash wastewater is temporarily stored in the backwash drainage tank 44, the turbidity in the backwash wastewater is likely to settle. There is an advantage that becomes better.

  In the iron / manganese-containing water treatment method and treatment apparatus according to the present embodiment, as described above, the iron / manganese-containing water is passed through the oxidation treatment tank 12 at a high linear velocity of, for example, 1,000 m / day or more. Of course, it can be applied to a conventional contact manganese sand filtration method in which iron / manganese-containing water is passed through the oxidation treatment tank in a downward flow.

  FIG. 3 shows an outline of another example of the iron / manganese-containing water treatment apparatus according to this embodiment. The iron / manganese-containing water treatment device 5 is configured such that, in the oxidation treatment tank 12, the oxidant-added water is passed in a downward flow and is oxidized by an oxidation catalyst containing filled manganese dioxide. 1 is the same configuration as the iron / manganese-containing water treatment apparatus 1 of FIG.

  FIG. 4 shows an outline of another example of the iron / manganese-containing water treatment apparatus according to this embodiment. In the iron / manganese-containing water treatment device 7, a backwash drainage tank 44 is installed in the middle of the backwash drainage pipe 40, and a pump 46 is installed in the middle of the backwash drainage pipe 40 on the outlet side of the backwash drainage tank 44. The structure is the same as that of the iron / manganese-containing water treatment device 5 of FIG.

  The water flow velocity by the downward flow in the oxidation treatment tank 12 is, for example, in the range of 120 m / day to 720 m / day, and preferably in the range of 140 m / day to 360 m / day. If the water flow velocity due to the downward flow in the oxidation treatment tank 12 is less than 120 m / day, the device may become large, and if it exceeds 720 m / day, the turbidity becomes clogged and the water cannot pass through immediately. There is.

  The iron / manganese-containing water treatment apparatus and treatment method according to the present embodiment can be suitably applied in, for example, a water purification plant, groundwater use water treatment, and the like.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

<Example 1>
The iron / manganese-containing water treatment apparatus described in FIG. 2 was used to treat iron / manganese-containing water. And, using the backwash wastewater (turbidity 25 degrees, 355 degrees) of the actual membrane filtration device, the turbidity of the washing wastewater when washed by passing water in an upward flow at different linear speeds to the oxidation treatment tank, The measurement was performed using an integrating sphere turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., WA2000 type). As an oxidation catalyst containing manganese dioxide, manganese dioxide catalyst particles having a β-type crystal structure with an effective diameter of 0.5 mm and a density of 4.0 g / cm ³ were used. As the filtration membrane, a PVC UF membrane was used. The results are shown in FIG.

  At a cleaning flux of 1,000 m / day, the turbidity in the cleaning water is slightly accumulated in the oxidation treatment tank regardless of whether the turbidity of the cleaning water (backwash waste water from the membrane filtration device) is 25 degrees or 355 degrees. As a result. On the other hand, in the cleaning flux range of 1,200 m / day to 3,600 m / day, the cleaning water almost flows out as it is as cleaning wastewater, and the backwash wastewater from the membrane filtration device is used as the cleaning water for the oxidation treatment tank. It was found that it can be used without inferiority.

  The manganese concentration of iron / manganese-containing water, which is the raw water treated using the iron / manganese-containing water treatment apparatus shown in FIG. 2, and the manganese concentration of the treated water were measured. An IPC mass spectrometer (manufactured by PerkinElmer, Inc., NexION) was used for the measurement. The results are shown in Table 1.

  Moreover, the recovery rate of the treated water with respect to the treated raw water when the cleaning interval is changed to 1 day, 2 days, 3 days, and 4 days using the iron / manganese-containing water treatment device shown in FIG. The calculated results are shown in Table 2.

<Comparative Example 1>
The iron / manganese-containing water treatment apparatus shown in FIG. 6 was used to treat iron / manganese-containing water. The iron / manganese-containing water treatment apparatus shown in FIG. 6 is a raw water tank 50, an oxidation treatment tank 52, a membrane filtration device 54, a treatment water tank 56, and an oxidant, similarly to the iron / manganese-containing water treatment apparatus shown in FIG. Although the tank 58 and the backwash drainage tank 60 were provided, the raw water of the raw water tank 50 was used as the cleaning water for the oxidation treatment tank 52, and the cleaning drainage was discarded.

  The manganese concentration of iron / manganese-containing water, which is the raw water treated using the iron / manganese-containing water treatment apparatus shown in FIG. 6, and the manganese concentration of the treated water were measured. The results are shown in Table 1. Table 2 shows the results of calculating the recovery rate of the treated water with respect to the treated raw water when treated with the iron / manganese-containing water treatment device shown in FIG.

  In both Example 1 and Comparative Example 1, the manganese concentration of the treated water could be reduced. In Comparative Example 1, the raw water was used as the cleaning water for the oxidation treatment tank, and the cleaning wastewater was discarded. On the other hand, in Example 1, since the oxidation treatment tank was washed using the backwash waste water obtained by backwashing the membrane filtration device as wash water, the recovery rate was high.

  As described above, the iron / manganese-containing water treatment device of Example 1 has a high water recovery rate, and the membrane filtration device can be stably operated.

  1,3,5,7 Iron / manganese-containing water treatment apparatus, 10,50 raw water tank, 12,52 oxidation treatment tank, 14,54 membrane filtration device, 16,56 treatment water tank, 18,58 oxidizer tank, 20, 22, 24, 46 Pump, 26 Raw water piping, 28 Raw water supply piping, 30 Oxidized water piping, 32 Membrane filtered water piping, 34 Treated water piping, 36 Oxidant piping, 38 Backwash water piping, 40 Backwash drainage piping, 42 Cleaning drainage pipes, 44, 60 Backwash drainage tanks.

Claims (2)

An oxidizing agent adding means for adding an oxidizing agent to iron / manganese-containing water containing at least one of iron and manganese;
An oxidation treatment tank filled with an oxidation catalyst containing manganese dioxide, which oxidizes the oxidant-added water to which the oxidant is added;
A membrane filtration device for membrane filtration of the oxidized treated water;
Backwashing means for backwashing the membrane filtration device;
Cleaning means for cleaning the oxidation treatment tank using at least a part of the backwash waste water that backwashed the membrane filtration device as cleaning water,
Equipped with a,
The cleaning of the oxidation processing tank cleaning flux 1,200～3,600M / day processor iron / manganese-containing water is performed in up-flow, characterized in Rukoto ranging. An oxidizing agent adding step of adding an oxidizing agent to iron / manganese-containing water containing at least one of iron and manganese;
An oxidation treatment step in which the oxidant-added water to which the oxidant has been added is passed through an oxidation treatment tank filled with an oxidation catalyst containing manganese dioxide to oxidize, and
A membrane filtration step of passing the oxidized treated water through a membrane filtration device and performing membrane filtration;
Backwashing step of backwashing the membrane filtration device;
A washing step of washing the oxidation treatment tank using at least a part of the backwash waste water that backwashed the membrane filtration device as washing water;
Only including,
A method for treating iron / manganese-containing water, wherein the washing of the oxidation treatment tank is performed in an upward flow with a washing flux in the range of 1,200 to 3,600 m / day .