JPH06182355A - Treatment of humic acid-containing water - Google Patents

Abstract

PURPOSE:To provide a simple flocculation treatment method reduced not only in the use amt. of a chemical agent but also in the generation amt. of sludge. CONSTITUTION:Flocculation treatment is performed using a mixture of aluminum chloride containing 1-5wt.% of a sulfur ion as SO4 and having basicity of 35-65% and polydimethyldiallylammonium chloride. By treating humic acid- containing water by this method, the use amt. of a chemical agent and the generation amt. of sludge are reduced as compared with a case using only a general inorg. flocculant. Further, excellent effect of extremely simplifying flocculation treatment operation is developed as compared with the combined treatment with a general high-molecular flocculant.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for treating water useful for water containing humic acid.

[0002]

2. Description of the Related Art In cold regions or areas of peat soil, humic acid is often contained in the surface water of lakes and rivers, and humic acid components elute from dead plants and leaves in mountainous areas. However, this often flows into river water.
In order to obtain clear water such as industrial water from lake waters and river water containing such humic acid, a coagulation treatment method using various coagulants is generally performed. As such an aggregating agent, an inorganic aggregating agent such as aluminum sulfate or polyaluminum chloride, or a polyacrylamide, or a partial hydrolyzate thereof, or an organic polymer aggregating agent such as an acrylate ester type is generally used to remove turbidity. At the same time, the chromaticity component derived from humic acid is removed.

However, in order to remove such a chromaticity component, the use of the above-mentioned inorganic coagulant requires a large amount of addition. Therefore, in the treated water treated in this way, the pH of the treated water becomes low, so naturally a large amount of the alkaline agent for this neutralization is required, and as a result, the amount of the treated sludge to be produced becomes large. Disposal method becomes a problem. Further, when a polymer flocculant such as polyacrylamide is used and such water treatment is carried out, flocs generated are small, and since flocs are light, flocculation and precipitation become difficult,
At present, the chromaticity component is hardly removed, and the removal of the chromaticity component has almost no effect.

[0004]

In view of such circumstances, the present inventors have conducted extensive studies on a method of obtaining clear water such as industrial water from lakes and river water containing humic acid components, and as a result, The present invention has been completed by finding that a mixture of aluminum chloride and polydimethyldiallylammonium chloride has a remarkable effect on the removal of humic acid components as well as general suspended components.

[0005]

Means for Solving the Problems That is, the present invention provides polyaluminum chloride and polydimethyldiallylammonium containing sulfate ions as SO _{4 in} the range of 1 to 5% by weight and having a basicity of 35 to 65%. It relates to a method for treating humic acid-containing water, which comprises using a mixture with chloride.

[0006]

[Function] The present invention uses 1 to 5% by weight of sulfate ion as SO _4.
In the range of 35 to 65% in basicity, and polyaluminum chloride (hereinafter abbreviated as PAC) and polydimethyldiallylammonium chloride (hereinafter DMDAC).
And abbreviated) are used as a mixture.

The PAC used in the present invention contains sulfate ion
It is contained in the range of 1 to 5% by weight as SO ₄ , and has a basicity of 35.
It is necessary to use one in the range of ~ 65%. That is, with respect to the amount of sulfate ion, SO ₄ deviates from this range and becomes 1
If it is less than wt%, its cohesive effect will decrease, and vice versa.
When SO ₄ exceeds 5% by weight, the polyaluminum chloride itself becomes unstable and precipitates are similarly formed, so that the coagulation effect is similarly reduced, and thus the effect of the present invention cannot be obtained. . With respect to the basicity, if the basicity is deviated from this range, the aggregating agent mixed will not only deteriorate the aggregating effect but also become unstable, and similarly the effect of the present invention cannot be obtained. Also,
DMDAC has an intrinsic viscosity of 0.6 dl / g or more at 25 ° C.

In the present invention, a mixture of PAC and this DMDAC is added to humic acid-containing water for coagulation treatment. In the present invention, it is particularly important to premix these, and the treatment is carried out. At this time, the effects of the present invention cannot be obtained even if these are added separately and used. Further, regarding the mixing ratio of PAC and DMDAC, the amount of Al ₂ O _{3 in} PAC and DMD
Mixing is performed so that the solid content of AC is in the range of 100: 4 to 50 by weight. That is, if the mixing ratio of both deviates from this range, the effect is the same as when used alone,
The effect of the present invention cannot be obtained. When this mixed drug is added to the target water containing humic acid while stirring,
Flocs quickly form and settle rapidly upon standing. By using an appropriate solid-liquid separation means,
The humic acid component is separated and removed together with the suspended component.

[0009]

The present invention will be further described below with reference to examples of the present invention, but the present invention is not limited to these examples.
Further, in the present invention, all% are by weight unless otherwise specified.
Indicates.

(Example 1) PAC (Al ₂ O ₃ 10%, SO ₄ 3%, basicity 50%, Taki Chemical Co., Ltd., trade name PAC250A) and DMDAC
(Solid content 20%, Intrinsic viscosity 1.3dl / g, Toa Gosei Chemical Industry Co., Ltd.
Manufactured by Aron Flock C-70) was used, and these were mixed at the ratios shown in Table 1 to carry out an aggregation test. Humic acid (reagent, manufactured by Wako Pure Chemical Industries, Ltd.) (10 g) was added to tap water (3 L), and sodium hydroxide (1.5 g) was further added thereto and dissolved by stirring. After leaving this for one day and night, suction filtration was performed using a filter paper (Toyo Filter Paper No. 5A). This filtrate was diluted with tap water so that the chromaticity was about 450 degrees, and this was used as the test raw water. In addition, the alkalinity of this test raw water was 34.9 mg / l and the pH was 7.45.

500 ml of the test raw water was placed in a 500 ml beaker, and a predetermined amount of the mixed flocculant of the present invention shown in Table 1 was added thereto while stirring with a jar tester at 120 rpm. After stirring for 10 minutes and then allowing it to stand for 10 minutes, 100 ml of supernatant water was collected and filtered through filter paper (Toyo Roshi Paper No. 5A). For comparison, polyaluminum chloride and DMDAC were used alone and similarly subjected to coagulation treatment. When two kinds of coagulant were used, the second coagulant was added 5 minutes after the addition of the first coagulant, and the same test as above was performed. The chromaticity and pH of the filtered water were measured, and the results are shown in Table 1. The measurement of chromaticity is 410m
It was performed by a colorimetric method at an absorption wavelength of μ. In addition, the addition amount of the aggregating agent is represented by the amount of each aggregating agent.

[0012]

[Table 1] Note: The mixing ratio of the coagulant is shown by the ratio of Al ₂ O ₃ content of PAC and the solid content of DMDAC, and the addition amount of the coagulant is shown by the addition amount of the mixture. (same as below)

Example 2 Using the humic acid of Example 1, a test raw water was prepared in the same manner. The chromaticity of this test raw water was 419 degrees, the alkalinity was 40.5 mg / l, and the pH was 7.29. As shown in Table 2, the PAC and DMDAC used in Example 1 were used to prepare aggregating agents having different mixing ratios thereof, and the aggregating test was conducted in the same manner as in Example 1 using the aggregating agents. The test results are shown in Table 2.

[0014]

[Table 2]

(Example 3) Humic acid (reagent, Wako Pure Chemical Industries, Ltd.)
5 g) was dissolved in 1 L of 0.05% sodium hydroxide, filtered through filter paper (Toyo Filter Paper No. 5A), and diluted with tap water so that the filtrate had a chromaticity of 200 degrees. 10 L of this diluted solution was taken, 300 mg of kaolinite (manufactured by Merck & Co., Inc.) was added thereto, and after stirring well, this was left for one day and used as a test raw water. The sample raw water had a chromaticity of 200 degrees, an alkalinity of 34.9 mg / l, a turbidity of 29.0 ppm, and a pH of 7.25. Using this test raw water, the coagulation test was conducted in the same manner using the coagulant of Example 1, and the supernatant water was collected to determine its chromaticity, turbidity,
The pH was measured. The results are shown in Table 3.

[0016]

[Table 3]

(Example 4) As in Example 1, humic acid was used to prepare a test raw water. The chromaticity of this test raw water was 167 degrees, the alkalinity was 45.5 mg / l, and the pH was 7.54. A coagulation test was conducted in the same manner as in Example 1 except that the coagulant of the present invention and DMDAC shown in Table 4 were replaced with a mixed coagulant obtained by mixing another type of polymer coagulant with PAC. The test results are shown in Table 5.

[0018]

[Table 4] Note) Takiflock C-403, C-420, C-804, C-808 are all Taki Chemical
Product name

[0019]

[Table 5]

Comparative Example 1 Kaolinite (Merck)
0.5 g was added to 10 L of water, stirred well, and allowed to stand for one day to be used as test raw water for a coagulation test. The sample raw water had an alkalinity of 37.5 mg / l, a turbidity of 44.2 ppm and a pH of
It was 6.79 and the chromaticity was 0 degree. Using the flocculant used in Example 1, a flocculation test is performed in the same manner as in Example 1 below.
100 ml of supernatant water was sampled and its turbidity and pH were measured.
The aggregation effect was determined by measuring the supernatant turbidity using an integrating sphere turbidimeter. The results are shown in Table 6.

[0021]

[Table 6]

For water containing humic acid as in Examples 1 to 4, the method of the present invention exhibits excellent flocculation performance, while for water containing no humic acid the results of Table 6 As is clear from the above, the method of the present invention has almost no effect. Therefore, the method of the present invention has its effect only on water containing humic acid.

(Example 5) PAC (Al ₂ O ₃ 10%, SO ₄ 3%, basicity 50%, Taki Chemical Co., Ltd., trade name PAC250A) and DMDAC
(Solid content 20%, Intrinsic viscosity 1.3dl / g, Toa Gosei Chemical Industry Co., Ltd.
Manufactured by Aron Flock C-70), and mixed at a ratio of 100/5 to obtain a flocculant. For comparison, polyaluminum chloride containing no sulfate group (PAC-1; Al ₂ O ₃ 10
%, SO ₄₀ %, basicity 50%), low basicity product (PAC-2; Al ₂ O ₃ 10%,
SO ₄ 3%, basicity 30%) and highly basic products (PAC-3; Al ₂ O ₃ 10%, S
O ₄ 3%, basicity 70%) were prototyped respectively, and these and the above DM
DAC was mixed at a ratio of 100/5 to obtain a flocculant for comparison. Using the sample raw water used in Example 1, Example 1
A coagulation test was conducted in the same manner as in. The alkalinity of this raw water is 3
It was 4.9 mg / l and pH was 7.45. Table 7 shows the test results
It was shown to.

[0024]

[Table 7]

[0025]

The water treatment method of the present invention has a specific proportion of PA.
By using C and DMDAC as a mixture, the effect becomes more excellent as compared with the case where these are added separately. In addition, compared with the case where only the inorganic coagulant is used, the amount used is generally smaller and the amount of sludge generated is also smaller.

Front page continuation (72) Minoru Okada 1 Minami-ku, Funami-cho, Minato-ku, Nagoya, Aichi Prefecture Toagosei Chemical Industry Co., Ltd. Nagoya Research Institute (72) Inventor Hajime Miwa 1296 Shinnobe, Beppu-cho, Kakogawa-shi, Hyogo −10 Address (72) Takuya Hosoda, Inventor Takuya Hosoda, 1406-1 Shinnobe, Beppu Town, Kakogawa City, Hyogo Prefecture

Claims (1)

[Claims] 1. A mixture of polyaluminum chloride and polydimethyldiallylammonium chloride containing SO _{4 in} the range of 1 to 5% by weight as SO ₄ and having a basicity in the range of 35 to 65% is used. A method for treating humic acid-containing water.