JP2607543Y2 - Hardness component and soluble metal removal device with permeable membrane - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing drinking water by means of a microfiltration membrane or an ultrafiltration membrane.

[0002]

2. Description of the Related Art Conventionally, filtration operations using a microfiltration membrane or an ultrafiltration membrane have been performed. According to these permeable membranes, almost 100% of insoluble substances can be removed.
There is a drawback that soluble components such as hardness components and manganese cannot be removed.Therefore, raw water containing soluble components such as hardness components and manganese cannot be subjected to water treatment that conforms to water quality standards with these permeable membranes. Atsuta.

On the other hand, the hardness component and soluble metal in water are p
Utilizing the property of precipitation when H is raised, there was a method of raising the pH of raw water and removing it by coagulation sedimentation or sand filtration. When the pH was neutralized, the remaining precipitates were redissolved again, resulting in a low removal rate of hardness components and metals.

[0004]

The permeable membrane can remove almost 100% of insoluble substances. For this reason, soluble components such as hardness components and some metals can be almost completely removed as long as they are precipitated.

[0005]

SUMMARY OF THE INVENTION Here, the present invention relates to a method of adding slaked lime to raw water containing a hardness component and a soluble metal.
By injecting an alkaline agent such as caustic soda or soda ash, or passing through a water tank filled with lime-based particles or a water tank in which slaked lime is dissolved, the pH of the raw water is increased, and the hardness components and soluble metals in the raw water are reduced. Precipitate,
This is permeated through an ultrafiltration membrane or a microfiltration membrane, and the pH of the permeated water is neutralized again with carbon dioxide or an acidic chemical to near neutrality. The present invention proposes a removing device.

[0006] When the pH of dissolved ions is increased by an alkaline agent, the heavy metal component dissolved in water is generally precipitated at a pH corresponding to the metal and becomes a suspension. Calcium, a typical hardness component, has a pH of 1
If it is not about 2 to 13, it will not precipitate, but if the pH is raised with slaked lime, it will precipitate as calcium carbonate at about pH 10.8. In this case, some soluble calcium in the water remains, but below the level required for water supply.

[0007] Therefore, if the pH is returned to neutral again after the precipitated substances are almost completely removed, the hardness can be reduced to the level required for drinking water. Further, when the pH is raised to about 10.8, most of soluble metals such as manganese and iron are also precipitated, and thus can be removed by the permeable membrane in the same manner as the hardness component. To make tap water,
The pH may be adjusted with carbon dioxide or an acidic chemical to lower the pH to around neutral suitable for drinking water.

[0008]

FIG. 1 shows a first embodiment of the present invention.
In this embodiment, raw water is supplied to a raw water pipe 1 by injecting a suitable amount of slaked lime solution 2 by an injection pump 3 so that the pH becomes 10.8 or more, and keeping it in an adjusting tank 4 to dissolve soluble calcium in raw water. After depositing the soluble metal, water is sent to the ultrafiltration membrane 7 by the circulation tank 5 and the circulation pump 6, and after the precipitated substances are removed by the ultrafiltration membrane 7, the water is discharged to the filtration water tank 8.

The ultrafiltration membrane 7 naturally removes turbidity and bacteria in the raw water.

In the filtration water tank 8, the treated water is supplied with a carbon dioxide gas cylinder 9
, A carbon dioxide gas is blown through the flow control valve 10 from
The H is returned to neutral, and sodium hypochlorite 11 is further injected by the injection device 12 so as to have a residual chlorine content, thereby obtaining drinking water.

Next, in a second embodiment shown in FIG.
Raw water flows into the slaked lime dissolving tank 22 via 1.
The slaked lime dissolving tank 22 is supplied with slaked lime 24 from a slaked lime replenishing tank 23 as needed.

[0013] The raw water rises in the slaked lime dissolving tank 22 to precipitate soluble calcium and soluble metal in the raw water, and is then sent to the ultrafiltration membrane 27 by the circulation tank 25 and the circulation pump 26. After removing the deposited substance by the ultrafiltration membrane 27, the substance is discharged into the filtration water tank 8.

The ultrafiltration membrane 27 naturally removes turbidity and bacteria in the raw water. In the filtered water tank 8, carbon dioxide gas is blown into the treated water from the carbon dioxide gas cylinder 9 via the flow control valve 10, the pH is returned to neutral, and sodium hypochlorite 11 is further injected by the injection device 12, and residual chlorine is injected. Allow for drinking water.

Further, in the third embodiment shown in FIG.
Raw water flows into slaked lime filling tank 32 via 1.
The slaked lime filling tank 32 is filled with fine slaked lime particles 33.

The slaked lime filling tank 32 is replenished with slaked lime particles from a slaked lime replenishing tank 34 as needed. After the raw water rises in the slaked lime filling tank 32 to precipitate soluble calcium and soluble metal in the raw water, the water is sent to the ultrafiltration membrane 37 by the circulation tank 35 and the circulation pump 36, After removing the deposited substance by the filtration membrane 37,
It flows out to the filtration water tank 38.

The ultrafiltration membrane 37 naturally also removes turbidity and bacteria in raw water. In the filtered water tank 38, carbon dioxide gas is blown into the treated water from the carbon dioxide gas cylinder 39 via the flow rate control valve 40 to return the pH to neutral, and sodium hypochlorite 41 is further injected by the injection device 42 to remove residual chlorine. And make it drinking water.

[0017]

According to the device having the above structure according to the present invention,
It is very useful for performing water treatment conforming to the water quality standard, because it can remove the hardness component and soluble metal contained in the raw water with high efficiency.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention.

[Explanation of symbols]

 1,21,31 Raw water pipe 6,26,36 Circulation pump 7,27,37 Ultrafiltration membrane 8,38 Filtration water tank 11,41 Sodium hypochlorite

Continuation of the front page (56) References JP-A-57-4204 (JP, A) JP-A-62-121694 (JP, A) JP-A-61-220793 (JP, A) JP-A-63-28486 (JP) JP-A-2-157090 (JP, A) JP-A-64-243696 (JP, U) JP-B-35-3833 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB Name) C02F 1/44 B01D 61/16 C02F 1/58 C02F 1/64

Claims (2)

(57) [Scope of request for utility model registration] An alkaline agent such as slaked lime, caustic soda or soda ash is injected into raw water containing a hardness component and a soluble metal component to raise the pH of the raw water, thereby reducing the hardness component and the soluble metal in the raw water. precipitate, which was transmitted through the ultrafiltration membrane or microfiltration membrane, the permeate, characterized in that to neutralize the re pH with carbon dioxide gas or acid chemicals to near neutrality, and hardness components by permeation membrane in water supply Dissolvable metal removal equipment. 2. The raw water containing the hardness component and the soluble metal component is passed through a water tank filled with lime-based particles or a water tank in which slaked lime is dissolved, and the pH of the raw water is raised, whereby the hardness component in the raw water and A permeable membrane for water supply, characterized by precipitating a soluble metal, permeating it through an ultrafiltration membrane or a microfiltration membrane, and neutralizing the permeated water again to near neutrality with carbon dioxide or an acidic chemical. Device for removing hardness components and soluble metals.