JP2847082B2 - How to purify pool water - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a purification method for keeping the quality of pool water in a swimming pool favorable by economical treatment.

[Conventional technology]

Regarding the quality of the pool water in the swimming pool, there is a statutory standard, and it is required that the water quality be above a certain level. However, the quality of water varies greatly depending on the number of pool users and the pool water purification system employed by each pool.

If you go to a pool where the pool water is not sufficiently purified, you may get eye diseases or have a so-called pool fever. Also,
If chlorination is strengthened so that this does not occur, swimmers will not be able to open their eyes in water,
A problem arises in that the color of hair and swimwear is bleached.

Also, it is not necessarily harmful even if a large amount of suspended solids is contained in the pool water, but the transparency of the water decreases,
The swimmer feels sensory discomfort.

In the conventional pool water purification treatment, generally, a part of the pool water is led to a pool water circulation treatment facility, first the hair is removed by a hair catcher, then treated with various filters, and then sterilized with chlorine to remove the pool. Was implemented by returning to. As the filter used here, a sand filter, a diatomaceous earth filter, a cartridge filter, and the like have been generally used.

However, in the treatment of pool water with these filters, only particles having a particle size of at most about 5 μm can be removed, which has a great effect on the transparency of water as well as bacteria.
Fine particles having a particle size of about 05 to 5 μm could not be removed. For this reason, in order to keep the transparency of the pool water good, it was necessary to supply fresh water of about 5 to 15% of the pool capacity per day. Further, since bacteria cannot be removed at all, it has been necessary to strongly perform chlorine sterilization and the like.

As a filtration technique for removing bacteria and fine particles in water, a method using membrane filtration using a hollow fiber and a method using a reverse osmosis membrane are known. Since the purification cost significantly increases when treated, it is not practical as a method for purifying swimming pool water.

On the other hand, it was known that the largest irritant in pool water for swimmer eyes was chloramine. This chloramine is a substance produced by the reaction of the disinfectant sodium hypochlorite with ammonia in the pool water, but no suitable method for removing this substance from the pool water has been known. For example, when simply trying to adsorb and remove chloramine using activated carbon, activated carbon adsorbs hypochlorite ions in the pool water or decomposes them into chloride ions and loses disinfecting power. It is easy to become a hotbed of breeding. Therefore, even if the chloramine in the pool water can be removed, it is necessary to supply a large amount of disinfectant to disinfect the treated water that has passed through the activated carbon layer.Therefore, use activated carbon to remove the chloramine in the pool water. Was hardly considered.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an economical treatment method for maintaining the water quality of a swimming pool at a high level, which is transparent and less irritating to eyes.

Another object of the present invention is to provide a method for purifying pool water that can significantly improve the quality of pool water by adding simple additional equipment to the existing pool purification equipment.

Still another object of the present invention is to provide a method of purifying pool water that can reduce the amount of fresh makeup water used for the pool.

[Means for solving the problem]

That is, the method of purifying pool water of the present invention comprises the steps of: treating pool water in a pool with a rough purification treatment line having a hair catcher and a filter and returning the pool water to the pool; and treating the pool water with the filter. Is guided to a microfiltration line having an activated carbon layer and a hollow fiber filtration device having a built-in porous hollow fiber filtration membrane, and is processed and returned to a pool as highly purified water.

[Preferred embodiment for carrying out the invention]

The pool water purification method of the present invention will be described based on the flow sheet shown in FIG.

In the method for purifying pool water of the present invention, the process of treating the pool water in the pool 1 in the rough purification treatment line (A) and returning the pool water to the pool includes the treatment of the water treated in the rough purification treatment line (the treated water after passing through the filter). ) To the precision purification processing line (B),
Here, a two-stage precision purification process is performed by an activated carbon layer and a hollow fiber filter having a built-in porous hollow fiber filtration membrane, and a step of returning the obtained highly purified water to a pool is added.

The rough purification treatment line (A) in the present invention may be any treatment line conventionally used as a purification treatment device for a pool as long as at least the hair catcher 2 and the filter 3 are provided. Good. Therefore,
In addition to the hair catcher and the filter, conventionally known various processing means may be provided, and for example, a heat exchanger, a sterilizing means, a circulation pump and the like may be provided. In the example of FIG. 1, a pump 4 and a disinfectant tank 5 for storing a disinfectant are additionally provided.

The hair catcher referred to here is a strainer mainly for removing hair and the like, and a typical example is a cage made of a punching metal having a hole having a hole diameter of about 1 mmφ. In addition, typical examples of the filter used here include a sand filter, a diatomaceous earth filter, a cartridge filter, and the like.

The flow rate of the rough purification treatment line is not particularly limited as long as it is at least 3 times the capacity / day of the pool stipulated by law, but usually about 6 to 10 times the capacity / day is appropriate.

In the precision purification treatment line (B) in the pool water purification method of the present invention, the adsorption treatment with activated carbon in the activated carbon layer 7 and the hollow fiber filter 8 incorporating the porous hollow fiber filtration membrane are performed.
And the resulting highly purified water is returned to the pool.

Various types of hollow fiber filtration machines having a built-in porous hollow fiber filtration membrane used in the method of the present invention can be used, and are not particularly limited, but continuously treat water to be treated. It is preferable to use a cross-flow type hollow fiber filter because it is suitable for the above. As a particularly preferred cross-flow type hollow fiber filtration machine, the inlet and outlet of water to be treated are disposed at both ends of a straight pipe, and a hollow fiber filtration membrane is disposed in the straight pipe substantially in parallel with the straight pipe. The permeated water filtered in the above is taken out from the side pipe connected to the side face of the straight pipe. For example, those disclosed in JP-A-61-291008 and JP-A-62-132503 shown in FIGS. 3 and 4 can be mentioned.

As the porous hollow fiber filtration membrane incorporated in the hollow fiber filtration machine 8 used in the method of the present invention, fine particles having a particle size of up to about 0.05 μm can be separated by filtration, and the processing flow rate per unit membrane area is relatively large. The microporous hollow fiber made of polyolefin is suitable, and a typical example thereof is a polyethylene porous hollow fiber (EHF, manufactured by Mitsubishi Rayon Co., Ltd.), which is appropriately hydrophilized. Is used.

The activated carbon layer 7 used in the method of the present invention is not particularly limited as long as it has a built-in activated carbon capable of adsorbing and removing chloramine in water, and various types can be used.

The arrangement of the hollow fiber filter 8 and the activated carbon layer 7 in the precision purification treatment line is preferably arranged such that water treated by the activated carbon layer is guided to the hollow fiber filter 8 for treatment.

By arranging the hollow fiber filter after the activated carbon layer, even if bacteria grow in the activated carbon layer, the permeation of bacteria can be prevented by the hollow fiber filter. Since sodium hypochlorite is removed by the activated carbon layer even when acid soda is introduced, deterioration of the hollow fiber membrane can be suppressed.

In the method of the present invention, the more the amount of the water to be treated guided from the rough purification treatment line to the fine purification treatment line, the more the pool water can be purified. Equipment is required and the amount of disinfectant used increases, which is not appropriate. Usually in the pool
An amount of about 0.3 to 0.9 times volume / day is preferred. Even at such a treatment flow rate, chloramine, bacteria, and even pool water
Fine particles having a particle size of about 0.05 to 5 μm can be halved.

The water to be treated guided to the fine purification treatment line is suitably treated in advance in the rough purification treatment line (treated water after passing through the filter). The pool water in the pool can be directly guided to the microfiltration circulation line for treatment.However, in this case, the clogging of the hollow fiber filtration membrane in the hollow fiber filtration machine is caused because there is too much suspended matter in the water to be treated. It is likely to occur early.

The water to be treated guided to the fine purification treatment line is usually treated first with an activated carbon layer and then with a hollow fiber filter. The non-permeated water of the hollow fiber filter is discharged out of the system as wastewater in principle.

The mode of disposing the hollow fiber filter in the precision purification processing line is not particularly limited, but as shown in FIG. 2, a plurality of cross-flow type hollow fiber filters 8a are provided.
To 8e are connected in series with the circulation pump 9 to form a circulation channel (C), and the treatment is preferably performed while circulating the water to be treated.

In the case of forming a circulation channel, the number of cross-flow type hollow fiber filters connected in series in one circulation channel is suitably about 2 to 10, and 3 to 8 It is preferably a group. With a radix number of the hollow fiber filtration device of this degree, if a sufficient processing flow rate cannot be obtained due to the membrane area of the hollow fiber filtration membrane, the processing flow rate is reduced by arranging a plurality of circulation channels in parallel. It is better to increase. If the number of installed hollow fiber filters in the circulation flow path is too large, the flow resistance of the circulation flow path is undesirably increased.

When the filtration process using the hollow fiber membrane in the circulation channel is continuously performed for a long time, the non-permeated water in the circulation channel is concentrated, and the suspended matter in the water to be treated is filtered by the hollow fiber filtration device in the cross-flow filter. Because of the deposition on the surface of the membrane, the treatment efficiency gradually decreases, and the flow rate of the obtained permeate decreases.

Therefore, a part of the permeated water of the cross-flow type hollow fiber filter is fed back to one or more of the cross-flow type filters to supply the outer surface of the hollow fiber filtration membrane in the cross-flow type filter. It is preferable to intermittently perform an operation of cleaning and removing the adhered deposits (hereinafter, the cleaning by this operation is abbreviated as “backflow”). That is, at the time of filtration, the outside of the hollow fiber filtration membrane was pressurized to allow the water to be treated to permeate the hollow portion of the hollow fiber and to take out the permeated water from the side pipe. Backwash control valves 10a-1 to allow permeated water to flow from the side pipe into the hollow fiber
Activating 1e (close one or two of 10a-10e and open one or two of corresponding 11a-11e) and apply water pressure to deposit sediment on the outer surface of hollow fiber Flush into the straight pipe.

This backwashing operation is performed in the circulation flow path even when the backwashing is performed by using another hollow fiber filter for filtration at the time of backwashing of some hollow fiber filters arranged in series. Processing capacity does not decrease much. That is, if the number of hollow fiber filters connected in series is 10 or less, perform backwashing of one or two hollow fiber filters at a time, and after the backwash is completed or after a further predetermined time, After the backwash of all the hollow fiber filters is completed by performing the backwash of the next hollow fiber filter, the backwash may be repeated in order from the first hollow fiber filter that has been backwashed. As a result, the filtering function of each cross-flow type filter can be sequentially restored without significantly reducing the processing capacity even during the backwashing, so that the fine purification processing line can always exhibit a sufficient filtering function. The backwash may be performed on two cross-flow filters at a time, but it is preferable to perform the backwash on only one at a time because safe operation can be performed.

When the backwash is performed, the sediment adhering to the outer surface of the hollow fiber is released into the straight pipe, so that the backwash drainage in which the dirt is concentrated in the circulation channel is generated. Therefore, in conjunction with the execution of this cleaning, the drain port 12 provided in the circulation channel is opened to discharge the backwash drainage. The number of drain ports is not limited to one, and may be provided, for example, as many as the number of cross-flow type filtration machines.
To open and close the drain port 12, for example, a drain control valve may be operated.

When the circulation channel is configured by connecting five cross-flow type hollow fiber filters in series, for example, backwashing for 20 seconds each for every 10 minutes is sequentially performed for each hollow fiber filter. It is possible to complete one cycle of backwashing of the entire circulation channel in 50 minutes. At this time, by appropriately operating the backwash control valves 10a to 11e, usually only one or two hollow fiber filters are backwashed, and for the remaining hollow fiber filters, normal membrane filtration is performed. It is good to carry out continuously.

The opening and closing of the drainage port 12 at the time of backwashing, taking into account the distance from the hollow fiber filter 8a to 8e that performs backwashing to the drainage branch pipe,
The discharge control valve may be opened to discharge the backwash drainage as the backwash drainage passes near the drain branch pipe.

The amount of backwash discharge is 0.005 to 0.02 times the volume of the pool /
It is appropriate to be on the order of days. In the case of a pool having only a conventional rough purification line, it is necessary to supply fresh water of about 5 to 15% of the pool capacity per day in order to keep the transparency of the pool water good. However, this method has an advantage that the amount of fresh makeup water can be reduced to about 1/10 to 1/5. For example, when a cartridge filter is used as a filter in the rough purification treatment line, only the backwash drainage of the hollow fiber filter may be discharged because the cartridge filter itself is not backwashed. If a machine is used, cleaning it requires 1-3% of the pool capacity per day. Therefore, the amount of fresh makeup water is
When a cartridge filter is used, it can be reduced to about 1/10, and when a diatomaceous earth filter or a sand filter is used, it can be reduced to about 1/5.

In the method of the present invention, part of the treated water treated in the rough purification line is first treated with an activated carbon layer to adsorb and remove chloramine, and then suspended particles and bacteria are removed by a hollow fiber filter. Obtain highly purified water and return this highly purified water to the pool.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the pool purification method of this invention, the advanced purification treatment of pool water can be economically implemented only by adding relatively simple additional equipment to the conventional pool purification facility.

In particular, the concentration of chloramine, the largest stimulant in the pool water, to the swimmer's eyes can be significantly reduced, and it has been difficult to keep the transparency of the pool water at about 15 m in the past, but it was increased to 25 m or more. can do.

In addition, adsorption purification treatment using activated carbon, which was considered unsuitable for pool water purification treatment, is used in combination with treatment using a hollow fiber filter, and only part of the pool circulation treatment water is guided to the activated carbon layer to treat it. This combination made it possible to incorporate activated carbon treatment into the pool water purification process.

Furthermore, when a cross-flow type filter is used as the hollow fiber filter and an intermittent backwashing method is adopted, the amount of fresh makeup water to the pool is reduced to about 1/10 to 1/5 of the conventional level. It is possible to reduce.

〔Example〕

Hereinafter, the method and apparatus for treating pool water of the present invention will be described more specifically with reference to examples.

Example 1 Purification of pool water was carried out by a pool water purification facility whose flow sheet is shown in FIG.

Capacity of the pool 1 is 400 meters ^3, crude purification processing line (A)
Pool water was supplied at a flow rate of 100 m ³ / hr. The hair catcher 2 has a diameter of 200 mm with many circular holes with a diameter of 1 mm.
A stainless steel basket with a diameter of 300 mm and a depth of 300 mm was used. A sand filter for processing 100 m ³ / hr was used as the filter 3, and a 12 wt% aqueous solution of sodium hypochlorite was added from the disinfectant tank 5 to 0.32%.
It was supplied at a flow rate of l / hr. In addition, a part of the treated water filtered by the filter 3 is 700 mm in diameter at a flow rate of 8 m ³ / hr through the pump 6.
Was supplied to an activated carbon layer 7 filled with coal-based activated carbon to a height of 1800 mm. In the circulation channel (C) in the precision purification processing line, five cross-flow type hollow fiber filters 8a to 8e having the structure shown in FIG. 3 and a circulation pump 9 are connected in series. At the same time, three such circulation channels were arranged in parallel (FIG. 2 shows only one circulation channel). The inner diameter of the straight pipe of each cross-flow type hollow fiber filtration machine is 6.5 cm, and the effective membrane area of the porous polyethylene hollow fiber filtration membrane (EHF manufactured by Mitsubishi Rayon Co., Ltd.) provided inside is 10 m ^2. Was.

One hour after the start of operation of the precision purification processing line, one cross-flow filter in each circulation channel is
Backwashing was performed by backflowing the permeated water at a flow rate of 1.2 m ³ / hr for 20 seconds. The drain port 12 was opened and discharged by operating a control valve in accordance with the backwash drainage generated by the backwash passing near the drain port.
The amount of wastewater was 4 t / day. Backwashing is sequentially performed on each cross-flow type filter every 10 minutes, so that one cycle of backwashing of one entire circulation channel is completed in 50 minutes, and this backwashing operation is continued thereafter. Was.

The pool was supplied with the same amount of fresh water as the backwash drainage discharged from the drain. The average number of swimmers in the pool was 400 a day.

Table 1 shows the water quality of the pool water after purifying the pool water for 10 days.

Comparative Example 1 In the pool used in Example 1, only the rough purification treatment line was operated, and the pool water purification treatment was performed without operating the precision purification treatment line. The pool was replenished with about 50 m ³ of fresh water per day, and the same amount of pool water was discharged out of the system. The average number of swimmers in the pool is 400 a day, and the consumption of disinfectant is 0.35 l / hr.
Met.

Table 1 shows the water quality of the pool water after purifying the pool water for 10 days.

Comparative Example 2 The pool water purification system used in Example 1 was used in exactly the same manner as in Example 1 except that a precision purification treatment line in which the activated carbon layer was removed from the precision purification treatment line was used. Purification treatment was performed.

In this example, the average number of swimmers in the pool was 400 per day, but the consumption of the disinfectant was 0.3 l / hr. Table 1 shows the water quality of the pool water after purifying the pool water for 10 days.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing a basic example of the pool water purification method of the present invention, and FIG. 2 is a flow sheet showing a more preferred embodiment of the pool water purification method of the present invention. 3 and 4 are schematic cross-sectional views showing a typical example of a cross-flow type hollow fiber filter used in the method of the present invention. 1: Pool, 2: Hair catcher 3: Filtration machine, 4, 6, 13: Pump 5: Disinfectant tank 7: Activated carbon layer 8, 8a-8e: Hollow fiber filtration machine 9: Circulation pump 10a-11e: Backwash control Valve 12: drain port 14: straight pipe, 15: hollow fiber 16: side pipe, 17: fixing member A: coarse purification processing line, B: precision purification processing line C: circulation flow path

Continued on the front page (72) Inventor Kazuo Kuwahara 2-3-19 Kyobashi, Chuo-ku, Tokyo Inside Mitsubishi Rayon Co., Ltd. (72) Inventor Akira Sakai 1-3-9 Irifune, Chuo-ku, Tokyo Diamond Sports Development (56) References JP-A-62-79809 (JP, A) JP-A-1-177353 (JP, U)

Claims (1)

(57) [Claims] 1. A process in which pool water in a pool is treated by a rough purification treatment line having a hair catcher and a filter and returned to the pool, and a part of the treated water treated by the filter is converted into an activated carbon layer. And a process for guiding to a microfiltration line having a hollow fiber filtration machine having a built-in porous hollow fiber filtration membrane, and returning to a pool as highly purified water.