JP2002119803A - Flocculating agent for treating bentonite-containing turbid water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flocculating agent for treating a bentonite-containing turbid water, which of easily gives supernatant liquid to perform the waste water treatment by improving the flocculation precipitation effect on the bentonite-containing turbid water conventionally difficult to be flocculated. SOLUTION: The flocculating agent for carrying out the waste water treatment for the bentonite-containing turbid water, in which bentonite is incorporated, a combined agent prepared by mixing a calcium based inorganic salt with an organic based high molecular flocculating agent and forms excellent floc rapidly and with excellent precipitation property to bentonite particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bentonite-containing turbid water treatment flocculant for coagulating and sedimenting bentonite particles in bentonite-containing turbid water used at construction sites and the like.

[0002]

2. Description of the Related Art Conventionally, for drainage treatment of turbid water generated at a construction site or the like, as shown in FIG. 2, turbid water is sent to a reaction vessel 2 of polyaluminum chloride (PAC agent), and fine soil in the turbid water is discharged. After the particles are formed into fine flocks by an agglutination reaction, a larger floc is formed by a cross-linking reaction of a polymer (polymer) flocculant in the polymer reaction tank 3, and the sedimentation speed is set to a high value so that the sedimentation tank (thickener) Then, the mixture is separated and settled while being stirred by a stirrer 5, and the supernatant water is transferred to a water storage tank 6 and pumped up by a pump 7 so as to be reused as clean water or discharged as waste water. .

By the way, bentonite (mineral name: montmorillonite) used to prevent spring water generated at construction sites and the like has a property of largely swelling in water, so that the spring water is stopped by swelling between sand particles. Water effect can be obtained.

However, the above flocculant does not have the effect of floc formation on such turbid water containing bentonite particles. Therefore, conventionally, the turbid water containing bentonite particles has to be treated by being discarded as it is. There was no situation.

[0005] Further, the conventional flocculant is strictly required to have an appropriate amount to be added to turbid water containing general soil particles, and if the amount exceeds the proper amount, it has an adverse effect on floc formation. Management was difficult, which led to higher labor costs.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been found to improve the effect of coagulation and sedimentation on bentonite-containing turbid water, which has been difficult to coagulate in the past, so that a clean supernatant can be easily obtained. An object of the present invention is to provide a bentonite-containing turbid water treatment flocculant that can obtain a liquid and perform wastewater treatment.

[0007]

In order to achieve the above object, the present invention relates to a flocculant for treating turbid water containing bentonite according to claim 1 of the present invention. Wherein a floc is formed on the bentonite particles at high speed and with good sedimentation by using a composite agent obtained by mixing an organic polymer flocculant with a calcium inorganic salt.

Further, the bentonite-containing turbid water treatment coagulant according to claim 2 of the present invention according to claim 1 uses calcium chloride as the calcium-based inorganic salt and acrylamide / acrylic acid as the organic polymer coagulant. It is characterized by using a soda copolymer.

The bentonite-containing turbid water treatment coagulant according to claim 3 of the present invention is characterized in that in claim 1, 98% by weight of calcium chloride is used as the calcium-based inorganic salt.
And an acrylamide / sodium acrylate copolymer as the organic polymer coagulant formed at a mixing ratio of 2% by weight.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

The bentonite-containing turbid water treatment coagulant according to the present invention is obtained by mixing an organic polymer coagulant with a calcium inorganic salt, using calcium chloride as the calcium inorganic salt and using an organic polymer coagulant as the organic polymer coagulant. A composite agent is formed by using an acrylamide / sodium acrylate copolymer.

According to the agglutination reaction by the aggregating agent of the present invention,
In an aqueous solution containing bentonite particles, a carboxyl group and an amino group in an organic polymer react with calcium ions of calcium chloride to form a hardly soluble metal complex compound having a large specific gravity and swell to form a bentonite particle having a small specific gravity. By cross-linking with, a chemically and physically stable coprecipitate can be formed.

For this reason, the co-precipitate of the hardly soluble metal complex compound and the bentonite component has a sedimentation speed which is much faster than that of other aluminum-based inorganic coagulants and forms stable flocs. Can be.

In order to treat turbid water by using such a flocculant for treating turbid water containing bentonite, as shown in FIG. 1, turbid water is transferred to an existing polymer reaction tank 3 and the turbid water is transferred to the existing reaction tank 3. Is supplied and reacted as a 10% aqueous solution.

Next, the floc formed in the sedimentation tank (thickener) 4 is separated and settled while being stirred by the stirrer 5, so that the supernatant water is transferred to the water storage tank 6, and the pump 7
And re-use it as clean water or drain it.

Hereinafter, the test results regarding the bentonite-containing turbid water flocculant according to the present invention will be described.

1. Test name: Test for confirming the flocculation performance of the flocculant according to the present invention with a bentonite-containing aqueous solution.

2. Test drug component: A mixture containing 98% by weight of calcium chloride and 2% by weight of an acrylamide / sodium acrylate copolymer.

3. Test purpose: This test is to confirm that the flocculant according to the present invention effectively shows a flocculating effect on hardly flocculent bentonite-containing turbid water.

4. Test method: Judgment is made based on the degree of transparency of the supernatant water by the measuring cylinder and the size of the floc.

5. Test preparation: (1) Sample preparation: 3 g of bentonite, a component described below
One liter of an aqueous solution was prepared (accurately weighed by an analytical balance). (2) A 10% (W / V) aqueous solution (PH:
9.9). (3) The measuring cylinder used was 1000 ml.

6. Test results Bentonite physical properties: true specific gravity 2.4-2.6 PH 9-10.5 particles 250 mesh [catalog value] Swelling degree 4.5-5.5 g / g 24 hr [catalog value] Bentonite chemical composition table: [catalog value]

7. Conclusion: The flocculating effect of the flocculant according to the present invention on the bentonite-containing turbid aqueous solution was sufficiently confirmed.

In the above test on the bentonite-containing turbid water flocculant, 98% by weight of calcium chloride as a calcium inorganic salt and acrylamide / sodium acrylate copolymer as an organic polymer flocculant by 2% by weight were used. %.

The effect of floc formation by the present flocculant depends on the concentration of bentonite, but it is extremely difficult to measure the bentonite concentration of turbid water every time flocculation is performed. It is impossible, and if the turbid water contains bentonite, the coagulant having a predetermined component ratio is added without considering the concentration if the turbid water contains bentonite.

The coagulant of the present invention is suitable for such a use, and has a calcium-based inorganic salt and an organic compound so as to have versatility in the coagulation effect of bentonite-containing turbid water generally generated at construction sites. The mixture ratio is adjusted to the polymer-based flocculant, and 98% calcium chloride and 2% acrylamide / sodium acrylate copolymer can obtain the best floc formation for ordinary bentonite-containing turbid water. The result was obtained.

When the conventional flocculant exceeds the proper amount, the floc formation efficiency is reduced. However, the flocculant according to the present invention has an economical suitable amount of the additive, but is not suitable for excessive addition. Since it does not affect coagulation, it is easy to control the amount of addition, it can be handled by anyone, and labor costs can be reduced.

The flocculating agent containing bentonite according to the present invention was able to obtain a good sedimentation effect by floc formation even in a flocculation test conducted on ordinary soil particles not containing bentonite.

Further, when the conventional flocculant forms flocs and then breaks down or dissolves again, it is necessary to add the flocculant again. In the above test, the flocculant was formed by the flocculant of the present invention. Looking at the situation after re-dissolving the floc by stirring the aqueous solution containing the floc, the sedimentation rate was the same as that when the flocculant was first added without adding the flocculant. Has been found to form flocs having

[0030]

As described above, according to the bentonite-containing turbid water treatment flocculant of the present invention, the bentonite particles in the bentonite-containing turbid water, which were difficult to coagulate with the conventional flocculant, are separated by good floc formation. , Can be settled at high speed.

Further, according to the coagulant of the present invention, the conventional P
It is possible to obtain a sedimentation effect by effective floc formation even in turbid water having a low turbidity and a large amount of fine particles, which was difficult to coagulate with the AC agent.

Further, although the coagulant of the present invention has an appropriate value for the economical addition amount, it does not affect the coagulation when added excessively, so that the addition amount control is simple and anyone can handle it.
Labor costs can be reduced.

The calcium chloride used as the calcium-based inorganic salt forming the flocculant of the present invention and the acrylamide / sodium acrylate copolymer used as the organic polymer flocculant are generally used materials. And can be used safely.

The coagulant of the present invention is a powder, and it is necessary to dissolve it when it is used. However, since it has excellent solubility, it can be uniformly dissolved in a short time.

Further, when the floc is broken or melted again after the conventional flocculant forms flocs, it is necessary to add the flocculant again. In the case of the present invention, the flocculant is not supplied again, but Flock can be formed.

[Brief description of the drawings]

FIG. 1 is a flow chart of a wastewater treatment apparatus using a bentonite-containing turbid water treatment flocculant according to the present invention.

FIG. 2 is a flowchart of a conventional wastewater treatment apparatus using a flocculant.

[Description of sign]

 2 ... PAC agent reaction tank 3 ... Polymer reaction tank 4 ... Thickener 5 ... Agitator 6 ... Water tank 7 ... Pump

Claims (3)

[Claims] 1. A flocculant for drainage treatment of bentonite-containing turbid water containing bentonite particles, wherein the composite agent comprising a calcium-based inorganic salt mixed with an organic polymer flocculant has a high speed with respect to the bentonite particles. A bentonite-containing turbid water treatment flocculant characterized by performing floc formation with good sedimentation. 2. The bentonite-containing turbid water according to claim 1, wherein calcium chloride is used as said calcium-based inorganic salt, and acrylamide / sodium acrylate copolymer is used as said organic polymer flocculant. Processing flocculant. 3. A mixing ratio of 98% by weight of calcium chloride as the calcium-based inorganic salt and 2% by weight of acrylamide / sodium acrylate copolymer as the organic polymer flocculant. The bentonite-containing turbid water treatment flocculant according to claim 1, characterized in that: