JPH07299470A - Dehydrating method of waste water such as milk - Google Patents

Abstract

PURPOSE:To rapidly dehydrate and improve efficiency by mixing polysaccharide into a waste water such as milk, then mixing a polyvalent metallic ion after mixing sodium alginate and then dehydrating. CONSTITUTION:Water is added into a prescribed quantity of a milk M to dilute, into which a prescribed quantity of the polysaccharide NGL10 is added and stirred. Next, a prescribed quantity of sodium alginate 20 is added and stirred. A prescribed quantity of the polyvalent metallic ion such as polyaluminum chloride aq. solution is added thereinto and mixed by stirring. And the mixed solution is left standing for a prescribed time until the solution is separated into a flocculated part and transparent water. After that, the solution is dehydrated by an adequate means, for example, the solution can be dehydrated by picking up the flocculated material with a pair of tweezers and holding between filters. A highly branched beta-1,3 glucane bonded with sulfoacetic acid and constituted so that a glucose having beta-1,3 gulcane in the main chain is branched at beta-1,6 bond is used as the polysaccharide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing technology for waste milk or other animal milk or dairy product processing plant waste liquid, and more specifically, it sequentially adds and mixes several different chemicals to milk waste liquid. Thus, the present invention relates to a method for dehydrating waste liquid such as milk, which enables rapid separation of organic substances and the like in milk from water.

[0002]

2. Description of the Related Art Conventionally, a method of diluting a concentrated milk waste liquid in a milk processing plant or a waste liquid obtained by washing a milk tank or the like, and then directly flowing it into sewer has been adopted. However, the BOD concentration is as high as 200 to 600 mg / l even if the effluent of a dairy processing plant or the effluent of a milk tank or the like is diluted. Since releasing this directly to rivers causes environmental destruction of the ecosystem, various means such as precipitation treatment of this waste liquid such as milk have been taken in recent years in a waste liquid treatment plant or the like.

[0003]

For example, JP-A-57-94 discloses a solution to the above-mentioned processing problem of milk waste liquid and the like.
The technique disclosed in Japanese Patent No. 386 has been proposed. This technology removes organic substances contained in milk as dehydrated cake by mixing concentrated milk processing plant waste liquid or milk to be discarded with excess sludge, and then adding acid to dehydrate it in the range of pH 5.5 to 3. It is a processing method. However, the acid itself was troublesome to store and handle. In addition, there is a problem in that it takes time and labor such as adding excess sludge to the milk to be discarded and mixing it, so that a quick and efficient dehydration process cannot be performed.

The present invention has been made on the basis of the above points, and an object thereof is to provide a dehydration method capable of quickly and efficiently dehydrating a concentrated milk processing plant waste liquid or waste milk. is there.

[0005]

Means for Solving the Problems In order to achieve the above object, the method for dehydrating a waste liquid such as milk according to the present invention comprises adding and mixing a polysaccharide to the waste liquid such as milk, and then adding and mixing sodium alginate to the waste liquid. After that, a polyvalent metal ion is added and mixed, and then dehydrated by an appropriate means.

Further, in the above treatment method, the polysaccharide is a β-1,3-glucan which is bound to sulfoacetic acid and is highly branched, and β-1,3-glucan is a main chain of which glucose is β-1,6-glucan. It is characterized by having a structure branched by a bond. With the above means,
We have succeeded in solving the above problems.

[0007]

The strict principle of the present invention has not been elucidated, but the strict test results have revealed the following. When polysaccharides, sodium alginate, and polyvalent metal ions are added to and mixed with the waste liquid such as milk in this order, the waste liquid such as milk agglomerates and gels, clearly separates water, and becomes a concentrated coagulated form. Separate into material and water. Then, when the coagulated substance is pressed, the dehydration action further proceeds. In particular, the polysaccharide binds sulfoacetic acid and is highly branched β-1,3
This is remarkable when it is a glucan and has a structure in which glucose is branched with a β-1,6-bond in the main chain of β-1,3-glucan.

When a polysaccharide or sodium alginate is added to a waste liquid such as milk, they are adsorbed on the surface of milk particles and, by stirring, collide with other particles and adhere to each other, resulting in flocs containing a large number of milk particles. To form. At the same time, whether sodium alginate ions act on the polysaccharide or due to its viscosity makes flocs easier to assemble, and when polyvalent metal ions are further added, sodium alginate becomes alginate fibers. It is speculated that the polysaccharides may also be converted to polysaccharide fibers and trap milk particles between multiple gel lattice structures. In other words, the primary aggregation of a portion of milk waste liquid that has aggregated due to the addition and mixing of polysaccharides progresses.Furthermore, when sodium alginate and polyvalent metal ions are added and mixed, the aggregated particles of milk waste liquid grow significantly. It is considered that the secondary agglomeration caused to proceed progresses, so that the dehydration treatment can be carried out quickly and efficiently.

[0009]

EXAMPLE An example of the present invention will be specifically described below. The polysaccharide to be used is β-1,3-glucan that binds sulfoacetic acid and is highly branched. Β-1,3
-Glucan in the main chain, chemical formula 1 (molecular weight of about 2 million n = 1
000-2000 Number of bound sulfoacetic acids = n / 10
Those having a structure in which glucose is branched by β-1,6-bonds such as 0) are preferable, and one such polysaccharide is NGL manufactured by Nippon Synthetic Chemical Industry Co., Ltd. And
It is said that the structural unit forms a chain molecule, and the chain molecule forms a complex triple helix structure through various bonds such as hydrogen bonds, and is fermented by a certain microorganism. It is said that it is produced, and gelation occurs when a certain kind of salt is added over a certain amount, and that it has an excellent condensing ability.

[0010]

[Chemical 1] On the other hand, sodium alginate is a substance that forms cell membranes of brown algae such as kelp, scabbard, and sea bream, and is used as an emulsion stabilizer, a viscous agent, a mold release agent, etc., and has strong hydrophilicity, cold water, hot water. It dissolves well in any of these and becomes a very viscous and homogeneous solution. Then, when a polyvalent metal ion is added to this, sodium ion replaces the polyvalent metal ion to form a gel-like substance at least the surface of which is insoluble in water.

The polyvalent metal ions include calcium ions, aluminum ions, magnesium ions, etc., and their metal salts such as, for example,
It may be added as an aqueous solution of poly (carminium chloride).

The above-mentioned "treatment method of dehydrating after adding / mixing each chemical" and known method "treatment method of drainage water by adding acid to dehydrate in the range of pH 5.5-3" In order to make a comparative examination, a dehydration treatment test shown in scheme 1 of FIG. 1 was tried using milk as a kind of waste liquid such as milk for experiment.

First, according to the present invention, in Scheme 1 of FIG. 1, 20 ml of milk M is taken out into a beaker and 2.3 ml of water W is added to dilute it, followed by 0.2 wt%.
1.5 ml of an aqueous solution of the above-mentioned polysaccharide NGL (10) is added and well stirred. Then, it is condensed into fine particles and dispersed throughout, and at this stage it does not appear to have taken off.

Subsequently, 0.5 ml of an aqueous solution of 2 g / 100 ml of sodium alginate 20 was added thereto,
Stir well for 40 minutes with a stirrer. At this stage, some water separation becomes clear, but it is observed as if the aggregates dispersed throughout the liquid became slightly larger.

Here, calcium chloride may be further added,
Aqueous solution of polyaluminum chloride 30 (Al ₂ O ₃ 11-
(13% content) 0.7 ml was added to make milk waste liquid Mo having a total volume of 25 ml, which was obtained by mixing three kinds of drugs. this,
Stir for 50 minutes with a stirrer by the method of "method 1". For the first time at this stage, what was agglomerated and dispersed greatly starts to bond, and the agglomerated portion and the transparent water portion are clearly separated. After this, if left for 20 minutes, the solidified substance aggregates to the extent that it can be picked up with hands or tweezers, and when it is crushed by being sandwiched between hands and filter paper, the water retained inside is condensed. Water is released and released, leaving only solid matter. The milk waste liquid in the above state is subjected to natural filtration 60 with filter paper (No. 1, Toyo Filter Paper, diameter 12.5 cm). Further, in the method of "Method 2", the mixture is stirred for 50 seconds with a stirrer for 50 seconds, and the filter paper (No.
2, natural filtration 60 with a diameter of 12.5 cm), and other dehydration treatment procedures are the same as in "method 1".

Next, a known means "adding an acid to pH
Examples of the "treatment method of wastewater for dehydration in the range of 5.5 to 3" will be described in Scheme 1 of FIG. First, the first means is to take 20 ml of milk M into a beaker, add 3.5 ml of water W to dilute it, and stir 40 for 1 minute with a stirrer. Subsequently, 1.5 ml of acetic acid containing 10% is added to obtain milk waste liquid Mo having a total volume of 25 ml. After stirring this for 1 minute or 45 seconds with a stirrer by the means of "method 1" or "method 2", and leaving it for 20 minutes, filter paper (No. 1 made by Toyo Filter Paper, diameter 12.5 cm)
Or filter paper (Toyo filter paper No2, diameter 12.5 cm)
Then, naturally filter 60.

The second means is to take 20 ml of milk M into a beaker, add 4.0 ml of water W to dilute it, and stir 40 with a stirrer for 1 minute. Then, 3.
Add 1.0 ml of 5% hydrochloric acid to make the total volume 25 ml.
Milk waste liquid Mo. After stirring this for 1 minute or 45 seconds with a stirrer by the means of "Method 1" or "Method 2", and leaving it for 20 minutes, it was filtered (No. 1 made by Toyo Roshi Co., Ltd., 12.5 cm straight line) or filter paper ( Natural filtration 60 is carried out using No.2 made by Toyo Roshi Kaisha, Ltd. (12.5 cm for the straight line).

The filtrate separated by the above dehydration method is subjected to "light transmittance measurement at a wavelength of 700 nm" 70 by a spectrophotometer. Next, FIGS. 2 and 3 comparing the results will be described. Fig. 2 shows that "stirring time is 1" according to "method 1".
According to the coagulant treatment of the present invention, the “light transmittance of the filtrate” is “80.3%”. On the other hand, in the conventional acetic acid treatment, “48.0
% "Permeability of filtrate", and hydrochloric acid treatment shows "5".
The "light transmittance of the filtrate" of "1.2%" is shown, and the superiority of the "light transmittance of the filtrate" according to the present invention is clear.

Further, FIG. 3 shows that "stirring time is 45 seconds" according to "method 2".
The "light transmittance of the filtrate" of "3.4%" is shown. On the other hand, the acetic acid treatment of the conventional method shows a “light transmittance of filtrate” of “60.1%”, and the hydrochloric acid treatment shows a “light transmittance of filtrate” of “73.8%”. The superiority of the “light transmittance of the filtrate” according to the present invention is also clear in “Method 2”.

[0020]

[Table 1] The "pH" of the milk M and the filtrate dehydrated by the method of the present invention, and "BOD (biochemical oxygen demand)" and "COD (chemical oxygen demand)" of the organic substances remaining therein Table 1 shows the results of comparison between In this test method, 15 g of a polysaccharide solution (0.5 wt%) and 12.5 g of a sodium alginate solution (2 wt%) are added to 500 g of milk and stirred. Then, 17.5 g of polyvalent metal ionic liquid (polyaluminum chloride aqueous solution) was added and stirred, and after standing for 20 minutes, suction filtration of the agglomerates was performed using a 12.5 cm Buchner funnel (No. 1, Toyo Filter Paper, diameter 12). 0.5 cm,
160 Torr). The filter cake (dehydrated cake) is
When it was dried and weighed, it was 50.6 g. As described above, according to the dehydration method of the present invention, the BOD / ppm of the organic substance contained in the milk M is reduced to 1/6 and improved, and the COD / ppm is reduced to 1 / 2.2 and improved. Was confirmed.

When any of the polysaccharides, sodium alginate, and polyvalent metal ions is omitted in each of the numerical values in the above-mentioned examples, the water separation state between the coagulated substance and water is not clear, and the synergistic effect thereof is not obtained. It was also confirmed that it was an action effect.

As described above, according to the embodiment of the present invention, the following effects can be obtained. First, the solid matter that becomes the dehydrated cake is insoluble in water, is non-adhesive, and becomes a large aggregate by using three kinds of chemicals as the aggregating agent. It can be easily filtered, does not clog, and requires very little pressure during dehydration. Furthermore, in this example, since natural polysaccharides and sodium alginate are used, this biodegradability is good, and it is advantageous in returning the solid matter after dehydration to the original soil properties, and the filtrate is BOD and COD even when released to the natural world
Is improved, which is advantageous. In addition, polyvalent metal ions do not adversely affect the natural environment and are highly safe.

It is needless to say that the present invention is not limited to the above-mentioned embodiments, and that the embodiments within the scope of the invention can be modified. For example, the polysaccharide or sodium alginate, polyvalent metal ion is not limited to the numerical value of each addition amount and the stirring time of the test example, and is not limited to the above-mentioned substances, similar agents of this It can be used. And
In the above-mentioned test example, the dehydration method using filter paper was described, but it goes without saying that other known dehydration means are appropriately adopted on an implementation scale.

[0024]

[Effect] As described in detail above, according to the method for dehydrating a waste liquid such as milk of the present invention, a large aggregate is formed by using several kinds of chemicals. There is no clogging, and the pressure during dehydration is extremely small, and a high dehydrating effect of quickly and efficiently separating organic substances and the like in milk from water can be obtained. Furthermore, since the above-mentioned several kinds of drugs use natural substance polysaccharides and sodium alginate which are natural extracts, this biodegradability is good,
It is advantageous in returning the solid matter after dehydration to the original soil properties, and is also advantageous in releasing the filtrate to the natural world because BOD and COD are improved. Further, since polyvalent metal ions also have a bad influence on the natural environment, 4, it is possible to provide an excellent dehydration method which does not damage the living environment from all aspects such as high safety.

[Brief description of drawings]

FIG. 1 is a flowchart showing a dehydration process in a diagram showing an embodiment of the present invention.

FIG. 2 is a bar graph showing the light transmittance of the filtrate according to an example of the present invention.

FIG. 3 is a bar graph showing the light transmittance of the filtrate according to an embodiment of the present invention.

[Explanation of symbols] 10 Polysaccharide 20 Sodium alginate 30 Polyvalent metal ion 40 Stirring 50 Stirring 60 Natural filtration 70 Light transmittance measurement M Milk Mo Milk waste liquid W Water

Claims (2)

[Claims] 1. A method comprising adding and mixing a polysaccharide to a waste liquid such as milk, then adding and mixing sodium alginate, and then adding and mixing a polyvalent metal ion, followed by dehydration treatment by an appropriate means. Method for dehydrating waste liquid such as milk. 2. The polysaccharide is a β-1,3-glucan that binds sulfoacetic acid and is highly branched. Β-1,3
The method for dehydrating waste liquid such as milk according to claim 1, which has a structure in which glucose is branched with β-1,6-bonds in the main chain of glucan.