JPS59105809A - Concentration of liquid by membrane - Google Patents

Abstract

PURPOSE:To prevent the adhesion of suspended substance or colloidal substance to a membrane surface to hold the amount of water to be permeated through the membrane to a good state, by converting the suspended substance or the colloidal substance in a liquid to a flocculated aggregate while controlling the pH of the membrane side residual liquid to a specific range. CONSTITUTION:When aluminum sulfate is added to the washing waste liquid with TDS of 400-6,000ppm containing suspended substance and colloidal substance in a raw water tank 2 in an amount of 150-170ppm as a flocculant while the pH of said waste liquid is adjusted to 5.3-5.7 by sulfuric acid. The waste liquid is raised in pressure to 40kg/cm<2> by a pressure pump 3 and passed through a cellulose acetate membrane 5 with a NaCl removal ratio of about 90% to be separated into a membrane permeate 6 and a membrane side residual liquid 7 while this residual liquid 7 is concentrated to 1/20-1/40 in a volume ratio. By this method, the suspended substance and the colloidal substance are subjected to the neutralization and coarse pulverization of the surface potential due to the addition of coagulant and pH adjustment and thereby the affinity with the membrane is lost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method to maintain the amount of water permeated through the membrane during the night, including suspended particles and colloidal substances that tend to adhere to the membrane, and to make the concentration of nucleic acids an OT function. Regarding the concentration method.

Generally, when membrane separation methods are used to process liquids containing organic or inorganic substances, suspended solids and colloidal substances adhere to the membrane surface, which can significantly reduce the amount of liquid that permeates through the membrane. As a countermeasure against this problem, pretreatment of the liquid to be treated is performed to remove substances that tend to adhere to the membrane surface. For example, pretreatment methods such as coagulation-sedimentation, sand filtration, centrifugation, and activated carbon adsorption treatment are carried out singly or in combination. However, these methods not only complicate the treatment system but also increase equipment costs. However, it has the disadvantage of significantly increasing running costs.

The present invention solves the above-mentioned drawbacks of the conventional method and provides lft! Membrane permeation treatment system for liquids containing turbid substances and colloidal substances (
The present invention provides a method for concentrating liquids using membranes that enables OT functionality for subdivision. A flocculant is added to make the suspended matter and colloidal matter into agglomerated aggregates, and the pH of the #Ii\ side residual liquid is controlled within the range of 5.3 to 5.7, and the amount of water permeated through the membrane is maintained at a predetermined level. There is a method of liquid concentration using a weighing membrane, which is characterized by the retention of

Next, the present invention will be explained with reference to the drawings.

Fig. 1 is a flow sheet diagram of one embodiment of the present invention, Fig. 2 is a graph showing changes in the amount of water permeated through a cellulose acetate membrane over time, and Fig. 3 is a permeation through the membrane when the volume is reduced to 1/2O It is a graph diagram showing a change in the number of water over time.

That is, the present invention adds a flocculant to the liquid to be treated to flocculate suspended matter and colloidal substances in the liquid to be treated, and adjusts the pH range necessary for the flocculant to effectively form a flocculated composite. In order to do this, after adding an acid or alkaline solution, it is treated with a membrane separator z, and the pH range is controlled within a certain range during the treatment. As the flocculant, hydroxides or salts of Fe, At, etc. are effective, as the acid, hydrochloric acid, sulfuric acid, etc., and as the alkali, sodium hydroxide is used.

According to the method of the present invention, suspended solids and colloidal substances that tend to adhere to the membrane are added to the membrane at a suitable pH level.
M forms an aggregate, which causes neutralization of the surface potential and coarsening of the particles, which causes them to lose affinity with the membrane and become difficult to adhere to the membrane due to the relationship with the membrane material used. Becomes the property of Thereby, when subjecting the liquid to be treated to the sliding door separation treatment, it is possible to significantly prevent a decrease in the amount of liquid passing through the canal due to an improvement in the cleaning ratio.

Further, as the isthmus used in the method of the present invention, hollow I
J4, flat film, ni-shaped film, and glue-wound film types are available. Materials used include cellulose acetate yarn, polyamide, polyester, polyacrylonitrile, and polysulfone yarn.
Inorganic materials such as metal water cargoes can be used. The working pressure at the switching end is approximately 0.2 tt/Cm.
, preferably 5 to 55 "J' f Otsu, 2.

In the flow sheet diagram of one solid line example of non-invention in FIG.
Raw water tank 2P'S pH 7.3, abrasive conductor 50υ~70
0 μv/. , TDI! The washing Wl waste liquid containing 1,400 to 600 ppln of suspension 'M' and colloidal substances was pressurized to '''/'m' with pressure pump 3, and NAC1lrk'
1E4 Approximately 90% cellulose acetate group 5 is separated at a raw water temperature of 20 to 30°C from 100% water 6 and 30% liquid 7 (generally included as condensate), and 4) Water 6 out of the system.
11! By taking out the remaining liquid from the structure, the volume is reduced to 20 to 1/4 o, which is 1%, or 1 ft9.

Next, this will be explained in more detail using %) A'F491I.

Figure 42 shows the IZR scene using the I-acid medicine.
*Filter C to the lowest pH of the folding skin, 5°5 (1011
), after the 4v IL ratio, the four pieces of U4 permeated water which were added to the cellulose acetate film and passed through the next cell were carbonized as shown in the m2 diagram. 7. After 90 minutes, the amount of water permeated through the machine was reduced to 1/2 after 1η of treatment.

On the other hand, in the method of the present invention, for the water outside the raw water tank 2, sft1tr aluminum (
A4 CC804) ・14-181110) 150
~1701) Add 2m and increase the final pH of 5 to 1
．． At the ψα head of 3 to 5.7 (r4t4 C10+1), tA trench L fc (') chi, a rci L,
4 t' ? The pH of Ia is (+tV(10+1)K!
When the PH value is controlled to be 5.3 to 5.7, a song N as shown in FIG. 3 is obtained.

Figure 43 shows valley 1 in one set of the inventive method using agglomeration 111.
This shows the change over time in the amount of water that permeates through the membrane when the volume is reduced to 1/20 in terms of actual volume.Since there is not enough raw water in the steep raw water tank 2, IJIl was added to 7A in a separate tank.
Takeka and the sulfuric acid in the magazine, the pH 4+i, and the hti
We adopted a method of adding qi to raw water tank 2 at the appropriate time. At the latest #1, I submerged 7601 membrane-AJ4 water in 5 uet of raw water '140t and at the same time.

+! ! In 4aa/, the depth of the burial mound was changed to Ōmukai, and it was recognized that a volume reduction of 14 degrees or more could be carried out efficiently. This is a combination of the water values for water and C6 water, and it can be seen that the effect is 4 good.

The pH of the #I tilted liquid of the top 11 mountains will rise over time, but if you leave it as it is and the pH reaches 6 or higher,
It was good to see that the 11 PH of the pseudo-permeable water mound was in the range of 5.3 to 5.717) and the recovery of t, i, ai water Ik was observed. Therefore, pH control is also a very important factor.

1, the flocculant is 1 by the beaker test.
, by changing the pH of the JJu embankment with the foundation adhesion agent and flocculant added, and visually observing the formation of crd fusuma flocs in each Toyo F, it was determined that the foundation flocs were sufficiently formed in the Jt final stage. Optimum pH for use of flags produced and final pH used
It is possible to determine the amount of fruit juice at t4 so that the value is around 5.5. Further, the upper limit of the pkI control range is determined from the final pH value at which #ll rough floc is sufficiently generated, and the upper limit is determined as the f4 range in which the acidity used does not become excessive.

As described above, in this @mei method, the TFI ICtp flocculant to be treated is added, and the pH is controlled at 1c/li when the flocculant exhibits a good effect, and the appropriateness of the cm flocculant and the pH conditions are 41 rj crack-work.

Table 1 Values in parentheses indicate pHtA values after concentration and odor control.

The effect of Mokukumei is the following 1 sitting.

11) Even if a complicated pre-treatment process is performed, it is possible to prevent the damage to the formation layer during shogi separation and to prevent the addition of colloidal abrasions, and to improve the effectiveness of the conversion process. Giru.

(2) By omitting the pretreatment process, equipment costs can be expected to be lower.

+3) Since it is possible to prevent the adhesion of particles and colloidal materials to the membrane surface, the frequency of cleaning the membrane can be greatly reduced.

[Brief explanation of drawings]

# & 1 Figure is a flow sheet diagram of one embodiment of the present invention, IJc
Figure 2 shows cell four-seed f without using a flocculant.
-4...4 Bonagraph diagram of the 4f version of Suiryo Toukami, 3rd diagram uses the 6th issue of the uninvented book, and the 1 da area ratio is 1/20
61. Changes over time of 11 prayers and 7 great ambiences at the time of 1c
FIG. In the figure, l... Stirring rock 50... Cellulose acetate canopy 200 Cool water tank 6... Draining shrine selection 14 Water 3-... l Ju pressure bong 7... Ht4
Suitable 11 Water 4...Φ・I base Q1 overwater tank

Claims (1)

[Claims] +1) When concentrating a liquid containing JIILG suspended matter and colloidal substances by membrane separation, an aggregating agent is added to the liquid to turn the suspended substances and colloidal substances into aggregates. Adjust the pH of the ventral residual fluid to 5.3 to 5.
Solution 1a: Concentration method using a membrane, which is controlled within the range of 7 and maintains the amount of water permeated through the membrane at a predetermined level.