JPH0214794A - Processing method for recycled waste liquid from ion exchange equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a reverse osmosis membrane device for seawater desalination, and an ion exchange device for producing pure water to purify the fresh water obtained by the device. The present invention relates to the effective use of recycled waste liquid from the ion exchange device in a water treatment device equipped with the above.

<Conventional technology> In factories, power plants, etc. that require pure water, salt 'R? Water with a low M degree is used as raw water, and the raw water is treated with an ion exchange device for producing pure water to obtain pure water. However, in places where it is difficult to secure a large amount of raw water with low salt concentration as mentioned above, such as factories located close to ocean areas or factories located on remote islands, seawater is first processed through a reverse osmosis membrane. Fresh water with a low salinity concentration is obtained by processing with a device, and pure water is obtained by processing the fresh water with an ion exchange device.

The ion exchange device is, for example, a hotbed type ion exchange device in which a column is filled with a mixed ion exchange resin of an H-type cation exchange resin and an OH-type anion exchange resin, or a hot-bed type ion exchange device in which a column is filled with a mixed ion exchange resin of an H-type cation exchange resin and an OH-type cation exchange resin. A two-bed type ion exchange device is used, in which different types of anion exchange resins are packed in separate towers, and pure water is produced by passing low-salinity Ff water as described above through the ion exchange device. It has gained.

In addition, if the capacity of the ion-exchange resin used by continuing water flow decreases or reaches a constant volume throughput, the cation-exchange resin can be replaced with mineral acids such as hydrochloric acid. , and anion exchange resin are respectively regenerated using an alkaline agent such as caustic soda, and each regenerated ion exchange resin is again subjected to pure water production as described above.

In this way, ion exchange equipment for producing pure water produces pure water while regenerating the ion exchange resin used almost regularly, and when this regeneration is performed, acidic A cation exchange resin regeneration waste liquid and an alkaline anion exchange resin regeneration waste liquid are discharged from the ion exchange apparatus. Conventionally, these recycled waste liquids have been mixed, neutralized, and then discharged.

<Problems to be Solved by the Invention> For the regeneration, an acid solution or alkaline solution with a concentration of about 3 to 5% is usually used as a regeneration chemical solution, and the regeneration chemical solution is passed through each ion exchange resin packed bed, Next, cleaning water such as pure water is passed through the ion exchange resin packed bed to wash away the regenerating agent remaining in the packed bed to complete the regeneration of the ion exchange resin. As a result of this regeneration, the cation exchange resin regenerated waste liquid including the washing waste water discharged during the washing and the anion exchange resin regenerated waste liquid are discharged from the ion exchange apparatus, and these are mixed as described above and then neutralized. be done.

As mentioned above, the regenerated waste liquid discharged from the ion exchange equipment is diluted with cleaning water such as pure water, so its salt concentration is considerably lower than the concentration of the regenerated chemical solution used. Normally 5,000 to 10
．． It is about 000 days/l.

Therefore, in factories where fresh water is obtained from seawater using a reverse osmosis membrane device and the fresh water is used to produce pure water, or where the fresh water has to be used as water for various processes, etc., the concentration of salts is low. The recycled salt concentration is only 1/3 to 1/6 of that of seawater, which is approximately 30,000 μ/β, and besides salts, it contains almost no pollutants such as suspended solids or organic matter. Waste liquid is a water resource of much higher quality than seawater, and it is not a good idea to release it as is. That is, if fresh water could be easily produced using the recycled waste liquid, it would be possible to use water effectively and also help reduce the amount of wastewater to be discharged.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a method for efficiently utilizing recycled waste liquid from an ion exchange device used for producing pure water.

<Means for Solving the Problems> The present invention provides a reverse osmosis membrane device for obtaining fresh water by treating seawater with a reverse osmosis membrane, and an ion exchange treatment for the fresh water obtained by the reverse osmosis membrane device to produce pure water. In a water treatment device comprising an ion exchange device for obtaining a This system is characterized by supplying mixed water to a reverse osmosis membrane device for treatment.

Effect〉 The present invention will be explained in detail below based on the drawings.

The drawing is an explanatory diagram of a flow showing an example of an embodiment of the present invention, and in the drawing, 1 is a reverse osmosis membrane device for desalinating seawater;
2 shows an ion exchange device for producing pure water. When desalinating seawater using a water treatment device as shown in the drawing, the raw seawater 3 is temporarily stored in a seawater storage tank 4, and then the raw seawater 3 in the storage tank 4 is passed through a filtration device such as a sand filter. Supply to 5.

At this time, for example, dichloride is added to the raw seawater 3 before the filtration device 5.
A flocculant such as iron is added, and the raw seawater 3 is oxidized with sodium hypochlorite, etc. to prevent the generation of microorganisms in the treatment system including the filtration device 5 and the reverse osmosis membrane device 1 in the subsequent stage. Add agent. The raw seawater 3 to which these chemicals have been added is supplied to the filtration device 5 to perform coagulation filtration, remove suspended solids, etc. contained in the raw seawater 3, and obtain clean filtered seawater, which is then transferred to the filtered water tank. 6. Store it once. Next, the filtered seawater in the tank 6 is supplied to the subsequent reverse osmosis membrane device 1 and subjected to reverse osmosis membrane treatment,
Fresh water 7, which is permeated water, is obtained on the permeate side of the membrane, and concentrated water 8 in which salts etc. are concentrated is obtained on the non-permeate side of the membrane.
is discharged from the system. On the other hand, the obtained fresh water 7 is stored in a fresh water storage tank 9.
The purified water 10 is supplied to the ion exchanger 2 via the ion exchanger 2 and subjected to ion exchange treatment to obtain pure water 10. Note that a part of the fresh water 7 is usually used for producing pure water, and the other part is often used as process water or the like.

If the performance of the ion exchange resin used in the ion exchange device 2 continues to produce pure water using the ion exchange device 2, or if a constant volume throughput has been reached, for example, using hydrochloric acid, The cation exchange resin and the anion exchange resin are regenerated using caustic soda using conventional methods.

The acidic cation exchange resin regeneration waste liquid and the alkaline anion exchange resin regeneration waste liquid discharged from the ion exchange device 2 by the regeneration are led to the waste liquid neutralization tank 11 and mixed.

Since the recycled waste liquid after mixing is usually alkaline, it is neutralized by adding an acid such as hydrochloric acid to it. After neutralization, the regenerated waste liquid 12 in the waste liquid neutralization tank 11 contains about 5,000
It contains only salts of ~10,000/1, and hardly any suspended solids. This is because the fresh water 7, which is the water to be treated by the ion exchange device 2, is permeated water obtained by treating seawater with a reverse osmosis membrane, and therefore contains almost no hardness components such as Ca and Mg. Even if the ion exchange resin treated with fresh water 7 is regenerated, the recycled waste liquid will hardly contain any hardness components. Therefore, even if the recycled waste liquid is neutralized, precipitates such as calcium carbonate will not be deposited.

In the present invention, the recycled waste liquid 12 after neutralization is mixed with seawater, which is the water to be treated by the reverse osmosis membrane device 1, and the mixed water is supplied to the reverse osmosis membrane device 1 for treatment. ? f
As mentioned above, since f112 is clear and contains almost no suspended matter, it is most suitable as water to be treated by the reverse osmosis membrane device 1, and does not require any special pretreatment. Specifically, for example, as shown in the drawing (regenerated waste liquid 12 in waste liquid neutralization tank 11 is led to raw seawater storage tank 4 and mixed with raw seawater 3, the mixed water is passed through a reverse osmosis membrane through a filtration device 5). Alternatively, the recycled waste liquid 12 can be mixed with filtered seawater immediately before the reverse osmosis membrane device 1 for treatment.

In this way, the recycled waste liquid 12 has a lower salt concentration than the raw seawater 3.
By mixing the raw seawater 3 with the raw seawater 3, the salt concentration of the water supplied to the reverse osmosis membrane device 1 can be lowered than that of the raw seawater 3, and as a result, the raw seawater 3 can be mixed alone from the reverse osmosis membrane device 1. Fresh water 7 with a lower salinity concentration can be obtained than in the case of treatment.

The reverse osmosis membrane device used in the present invention may be of any type, such as a spiral type, hollow fiber type, or tube type, and the material of the reverse osmosis membrane used may be a synthetic polymer membrane such as polyether or polyamide, or a cellulose acetate membrane. It can be anything like that.

Further, the ion exchange device for producing pure water is not limited to the above-mentioned mixed bed type ion exchange device or two bed type ion exchange device, but any type may be used.

<Effects> According to the present invention, recycled waste liquid discharged from an ion exchange device for producing pure water is mixed with seawater and subjected to reverse osmosis membrane treatment at the front stage of a reverse osmosis membrane device installed for seawater desalination. By doing so, it is possible not only to reduce the volume of wastewater that should be disposed of, but also to lower the salt concentration of the water supplied to the reverse osmosis membrane device than that of seawater, and therefore to reduce the salt concentration of the water supplied to the reverse osmosis membrane device compared to that of seawater. This has the effect of being able to obtain fresh water with a low salt concentration. As a result, the ion load on the ion exchange device for converting the fresh water into pure water is reduced, and the throughput of the ion exchange device can be increased.

Moreover, since the present invention desalinates the recycled waste liquid using a reverse osmosis membrane device originally installed for seawater desalination,
It is of great practical value as there is no need to newly install water supply equipment for recycled waste liquid, and it can be done by simply changing the piping.

[Brief explanation of the drawing]

The drawing is an explanatory diagram of a flow showing an example of an embodiment of the present invention. 1... Reverse osmosis membrane device 2... Ion exchange device 3
... Raw seawater 4 ... Seawater storage tank 5 ... Filtration device 6 ... Filter water tank 7 ... Fresh water 9 ... Fresh water storage tank 11 ... Waste liquid neutralization tank 8 ... Concentrated water 10 ...Pure water 12...Recycled waste liquid procedure amendment (method) October 27, 1988 Director General of the Patent Office Yoshi 1) Moon Tsuyoshi 1, Indication of the case 1988 Patent Application No. 160619 2, Title of the invention Processing method for recycled waste liquid from ion exchange equipment 3, relationship with the amended case Patent applicant address 5-16 HonyJ5-chome, Bunkyo-ku, Tokyo Name (440) Organo Co., Ltd. Representative Previous
1) Yong Ke 4, Agent Address: 113, 812-5151 5, Date of amendment order: September 7, 1985 (all date sent: September 27, 1988)
Please correct the following items in the statement. 1, page 6, line 1, page 4, line 8, line 6 from the bottom of page 8,
On the 5th line from the bottom of page 10, the word “Drawing” is replaced by “Figure 1”
I am corrected. Please correct the drawing as shown in attached Figure 1. that's all

Claims (1)

[Claims] A water treatment comprising a reverse osmosis membrane device for obtaining fresh water by subjecting seawater to reverse osmosis membrane treatment, and an ion exchange device for obtaining pure water by subjecting the fresh water obtained by the reverse osmosis membrane device to ion exchange treatment. In the device, the regenerated waste liquid discharged when the ion exchange device is regenerated is mixed with seawater that is the water to be treated by the reverse osmosis membrane device, and the mixed water is supplied to the reverse osmosis membrane device for treatment. A method for treating recycled waste liquid from an ion exchange device, characterized by: