JPH1015560A - Polymeric flocculant and waste water treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymeric flocculant high in the clarifying, capacity of a suspension and to enhance the clarifying effect of the suspension using the polymeric flocculant. SOLUTION: A polymeric flocculant containing carbon black is used or the polymeric flocculant is used together with carbon black to flocculate a suspended substance and flocs are removed by filtering to perform waste water treatment. A polymeric compd. used as the polymeric flocculant may be a sulfonate of a polystyrenic resin or a nonionic or anionic acrylamide resin, a cationic resin or a combination of them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer flocculant suitable for wastewater treatment, and to a wastewater treatment method using such a polymer flocculant.

[0002]

2. Description of the Related Art At present, there is a great deal of global interest in environmental issues, but securing water resources is one of the most important issues. In such a situation,
From the viewpoint of preventing water and environmental pollution, the Water Pollution Control Law, etc.
Legal regulations on wastewater from factories and homes are becoming more stringent.

As a countermeasure against wastewater, a treatment for cleaning wastewater with various polymer flocculants is performed. Currently, commonly used polymer flocculants include nonionic anionic flocculants for industrial wastewater treatment and cationic flocculants for sewage and human waste treatment. These coagulants are properly used depending on the application, but in any case, it is required that the suspension is excellent in clarification, concentration, and dehydration rate. Above all, regarding the clarification ability of the suspension, the required level tends to be particularly severe from the viewpoint of environmental conservation since the filtrate after the coagulation treatment is discharged as it is to general rivers, seas, lakes and marshes.

In such a situation, by combining two kinds of polymer coagulants or using a metal compound and a polymer coagulant in combination, the chemical oxygen demand (COD) in the filtrate can be reduced. Attempts have been made to reduce turbidity.

[0005]

However, according to the conventional techniques, the clarification ability of the suspension cannot be said to be sufficient, and a more excellent technique is desired.

Accordingly, an object of the present invention is to provide a polymer flocculant having a high clarifying ability of a suspension,
It is another object of the present invention to provide a wastewater treatment method using such a polymer flocculant, which has a high clarification effect of a suspension.

[0007]

The inventors of the present invention have made intensive studies on achieving the above object, and as a result, have used a polymer flocculant containing carbon black, or It has been found that the clarification effect of the suspension can be enhanced by using it together.

That is, the polymer flocculant according to the present invention is characterized in that the polymer flocculant is mainly composed of a polymer compound and contains carbon black. The coagulant is added to the waste water to coagulate the suspended substance, and the coagulated matter is removed by filtration.

Alternatively, in the wastewater treatment method according to the present invention, a suspended solid is aggregated by adding a polymer flocculant mainly composed of a high molecular compound and carbon black to wastewater, and the aggregate is filtered by filtration. To get rid of it.

The polymer compound used as the polymer flocculant may be a sulfonate of a polystyrene resin, a nonionic or anionic acrylamide resin, or a cationic resin. You may. Further, these may be used in combination.

When a polystyrene resin sulfonate is used, the polystyrene resin may be a sulfonate. The polystyrene resin may be not only a virgin material but also a waste material. For this reason, the present invention is also very effective as a method for recycling polystyrene resin products produced in large quantities as general-purpose resins. In addition, many waste materials of polystyrene resin originally contain carbon black. In this case, by using this as a sulfonate, a polymer flocculant containing carbon black can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments to which the present invention is applied will be described in detail.

In the present invention, wastewater treatment is performed using a polymer flocculant containing carbon black or using a polymer flocculant together with carbon black.

The carbon black used here may be those generally used as a colorant or reinforcing agent for a resin or an agent for imparting electric conductivity. And it may be manufactured by any of the channel method, the furnace method, and the thermal method.Even if the one manufactured by any one method selected from these is used alone, by a different method. Those manufactured may be used in combination. Further, the average particle diameter is preferably 5 to 500 nm, more preferably 10 to 50 nm.

When the carbon black is present in the waste water, small aggregates are formed with the fine suspended particles and organic components in the waste water using the carbon black as a nucleus. The small aggregate forms a large aggregate with the polymer flocculant, thereby reducing the turbidity and COD of the aggregate filtrate.

For this reason, the same effect can be obtained whether the carbon black is contained in the polymer flocculant or added separately from the polymer flocculant. It is easier to uniformly disperse the polymer flocculant in the wastewater at the time of adding the polymer flocculant, and the time and equipment for separately adding the polymer flocculant and carbon black are unnecessary, It is more preferable because the operation can be simplified.

When separately added, either the polymer flocculant or carbon black may be added first, but it is more preferable to add carbon black first.

When carbon black is contained in the polymer flocculant, the content of the carbon black is 0.01 to 20% by weight, preferably 0.05% by weight, based on the polymer component of the polymer flocculant. -10% by weight. Also,
When carbon black is added to wastewater separately from the polymer flocculant, the amount of carbon black added to the wastewater is
Depending on the concentration of the suspended solid (SS), it is usually 0.0
05 to 1000 ppm, preferably 0.01 to 200 ppm
ppm. If the amount of carbon black is small,
The effect of reducing the turbidity and COD of the filtrate after coagulation becomes insufficient. Conversely, if the addition amount is too large, carbon black itself may remain in the coagulated filtrate or hinder coagulation. Becomes

The polymer compound constituting the polymer flocculant may be a polystyrene resin sulfonate,
The resin may be a nonionic or anionic acrylamide resin or a cationic resin. Further, these may be used in combination. Hereinafter, nonionic polymer flocculants, anionic polymer flocculants, and cationic polymer flocculants are exemplified.

<Nonionic polymer flocculant> Polyacrylamide and polymethacrylamide. Preferred is polyacrylamide.

<Anionic polymer flocculant>-As (meth) acrylic acid resin, polyacrylamide or partially hydrolyzed polymethacrylamide, copolymer of acrylic acid or methacrylic acid and acrylamide or methacrylamide, and Tertiary copolymer of salts, acrylic acid or methacrylic acid, acrylamide or methacrylamide, 2-acrylamido-methylpropanesulfonic acid or vinylsulfonic acid or vinylmethylsulfonic acid and salts thereof, preferably a partial hydrolysis of polyacrylamide Decomposed products, copolymers of acrylic acid and acrylamide and salts thereof, terpolymers of acrylic acid and acrylamide and 2-acrylamide-methylpropanesulfonic acid and salts thereof ・ Polythrylene sulfonate polymer Te, polystyrene, styrene - butadiene, styrene - acrylonitrile, styrene - butadiene - acrylonitrile, styrene - (meth) acrylic acid, styrene - (meth) acrylic acid ester (number of carbon atoms is from 1 to 4 aliphatic hydrocarbon),
Styrene-acrylonitrile- (meth) acrylate (aliphatic hydrocarbon having 1 to 4 carbon atoms), styrene-
Butadiene- (meth) acrylate (having 1 carbon atom)
-4 aliphatic hydrocarbons), styrene-maleic anhydride,
Styrene-itaconic anhydride Among them, polystyrene, styrene-butadiene, styrene-acrylonitrile, styrene-butadiene-acrylonitrile, styrene-maleic anhydride-Other polymers include polyphenylene ether,
Polycarbonate, polyphenylene sulfide, polyethylene terephthalate Preferably, polyphenylene ether, polycarbonate Note that as the anionic polymer coagulant, in particular, polystyrene resin products produced in large quantities as versatile resins can be reused. Sulfonates are preferred.

<Cationic polymer flocculant> A quaternized product of dialkylaminoalkyl (meth) acrylate (methyl chloride, benzyl chloride or the like as a quaternizing agent) or an acid salt (hydrochloride as an acid salt) Inorganic acid salts such as sulfates and organic acid salts such as acetates) or polymers and copolymers of these with (meth) acrylamide, for example, quaternized methyl chloride of dimethylaminoethyl acrylate or acrylamide Polymer or copolymer ・ Dialkylaminoalkyl (meth) acrylamide quaternary compound or acid salt or polymer and copolymer thereof with (meth) acrylamide, for example, dimethylaminopropylacrylamide methyl chloride quaternary compound and acrylamide Copolymerization with cationization of polyacrylamide For example, Mannich denatured product and Hoffman decomposition product of polyacrylamide ・ Epihalohydrin-amine condensate For example, polycondensate of epihalohydrin and alkylene diamine having 2 to 8 carbon atoms ・ Polydimethyldiallylammonium chloride ・ Dicyandiamide condensate For example, dicyandiamide and Formalin condensate of ammonium chloride ・ Polyethyleneimine ・ Polyvinylimidazoline ・ Chitosan acid salt Among cationic polymer flocculants, especially, quaternized or acid salts of dialkylaminoalkyl (meth) acrylate or acid salts thereof Polymers or copolymers with (meth) acrylamide, quaternized or acid salts of dialkylaminoalkyl (meth) acrylamide or polymers or copolymers of these with (meth) acrylamide, It is preferred with an acid salt of chitosan.

As the above various polymer flocculants, a plurality of the same ionic species may be mixed or different ionic species such as anionic / nonionic and cationic / nonionic. A plurality of species may be mixed and used.

When a polystyrene resin sulfonate is used, even if it is newly produced (virgin material) for producing a polymer flocculant, it is discarded from factories, stores, homes, etc. (Virgin material) or a combination of virgin material and waste material. From the viewpoint of reusing a large amount of polystyrene resin products produced as general-purpose resins and preserving the global environment, it is preferable to use waste materials rather than virgin materials as polystyrene resins. In addition, many waste materials of polystyrene resin already contain carbon black. In this case, a coagulant containing carbon black can be obtained by using the polystyrene resin as a sulfonate.

In order to sulfonate the polystyrene resin, the polystyrene resin may be dissolved or dispersed in an organic solvent in advance, and a sulfonating agent may be added thereto. After sulfonation, a neutralization treatment may be performed by reacting with a basic compound, and the solvent may be removed by liquid separation, distillation, or the like. As the solvent, an aliphatic halogenated hydrocarbon having 1 to 2 carbon atoms typified by 1,2-dichloroethane or an alicyclic compound typified by cyclohexane is preferable.

[0026]

EXAMPLES Here, wastewater treatment was actually performed by combining various polymer flocculants and carbon black, and the performance was evaluated.

Example 1 A 25% by weight aqueous solution of sodium polystyrene sulfonate was prepared as a polymer coagulant, and 0.1% by weight of carbon black (for plastic color, HCC type, average particle size 9 to 14 nm) was added thereto. And add
Dispersed. This is a sample of the first embodiment.

Example 2 High-impact polystyrene containing carbon black (used VHS cassette tape housing material,
Carbon black (containing 2% by weight) was dissolved in 1,2-dichloroethane, and sulfuric anhydride was added dropwise at 20 to 25 ° C. to perform a sulfonation reaction. Thereafter, an aqueous solution of sodium hydroxide in an equimolar amount with sulfuric anhydride was added to neutralize the solution, and the solvent was distilled off to obtain an aqueous solution of a polymer coagulant having a polymer component of 20% by weight. In addition,
Here, 0.2% by weight of carbon black is contained. This is used as a sample of Example 2.

Example 3 A 0.05% by weight aqueous solution of a polyacrylamide partial hydrolyzate was prepared as a polymer flocculant, and the same carbon black as in Example 1 was added thereto to a concentration of 0.005% by weight. And dispersed. This is a sample of Example 3.

Example 4 The sample of Example 1 and the sample of Example 3 were mixed at a volume ratio of 1: 1. This is a sample of Example 4.

Example 5 A 0.2% by weight aqueous solution of a quaternary methyl chloride polymer of dimethylaminoethyl methacrylate was prepared as a polymer coagulant, and 0.01% by weight of the same carbon black as in Example 1 was added thereto. % And dispersed. This is a sample of Example 5.

Comparative Example 1 An aqueous solution was prepared in the same manner as in Example 1 except that no carbon black was added. That is, a 25% by weight aqueous solution of sodium polystyrene sulfonate is used as a sample of Comparative Example 1.

Comparative Example 2 The same aqueous solution as in Example 3 was prepared except that no carbon black was added. That is, a 0.05% by weight aqueous solution of the polyacrylamide partial hydrolyzate is used as a sample of Comparative Example 2.

Comparative Example 3 An aqueous solution was prepared in the same manner as in Example 4 except that no carbon black was contained. That is, a 1: 1 (volume ratio) mixture of the sample of Comparative Example 1 and the sample of Comparative Example 2 is used as the sample of Comparative Example 3.

Comparative Example 4 The same aqueous solution as in Example 5 was prepared except that no carbon black was added. That is, a 0.2% by weight aqueous solution of a quaternary methyl chloride polymer of dimethylaminoethyl methacrylate is used as a sample of Comparative Example 4.

The following experiments were conducted to evaluate the wastewater treatment capacity of the above samples.

That is, first, the wastewater (pH
A suspension prepared by adding 500 ppm of aluminum sulfate to 3.2, a suspension substance (SS) concentration of 0.5% by weight and a chemical oxygen demand (COD) of 50 ppm was prepared as an aggregation evaluation suspension. Then, this suspension for agglutination evaluation was added to a stoppered 2
100 ml was placed in a 00 ml measuring cylinder, and the samples of Examples 1 to 4 and Comparative Examples 1 to 3 were added to the suspension for aggregation evaluation in an amount of 5.0 ppm of the polymer.
Then, the graduated cylinder was immediately stirred up and down 10 times and allowed to stand, and the sedimentation speed of suspended particles, the turbidity of the filtrate after aggregation, and the COD of the supernatant were measured. Table 1 shows the measurement results.
Shown in

[0038]

[Table 1]

As shown in Table 1, the samples of Examples 1 to 4 all have basic characteristics as a polymer flocculant. Particularly, the effect of reducing the turbidity of the filtrate after flocculation is due to the combined use of carbon black. It turns out that it is superior to the sample of Comparative Examples 1-3 which does not.

From the results, it can be seen that the combined use of the polymer flocculant and carbon black can greatly improve the wastewater treatment capacity, particularly the clarification capacity of the suspension. In addition, it was found that sodium polystyrene sulfonate and partially hydrolyzed polyacrylamide can be used as the polymer flocculant, and that manufactured from used polystyrene resin can also be used as sodium polystyrene sulfonate. .

Next, the mixed sludge of the sewage treatment plant (pH 6.
8, a suspension substance (SS) concentration of 2.8% by weight and a chemical oxygen demand (COD) of 250 ppm) were prepared as a suspension for evaluating aggregation. Then, the samples of Example 5 and Comparative Example 4 were added to the suspension for agglutination evaluation during stirring with a jar tester at 0.5% by weight per SS, and the sedimentation speed and the turbidity were maintained. The COD of the supernatant was measured.
Table 2 shows the results.

For reference, two carbon blacks were used.
The same measurement was performed when the sample of Comparative Example 4 was added at 0.5% by weight per SS after adding 00 ppm. The results are shown in Table 2 as Example 6.

[0043]

[Table 2]

As can be seen from Table 2, Example 5 in which carbon black and an aqueous solution of a polymer flocculant were mixed in advance, compared to Comparative Example 4 in which no carbon black was used, In Example 6 in which the aqueous solution of the molecular flocculant was added, the drainage treatment capacity, particularly the clarification ability of the suspension, was greatly improved. This indicates that the combined use of the polymer flocculant and the carbon black can greatly improve the wastewater treatment capacity regardless of the timing of adding the carbon black.

[0045]

As is clear from the above results, application of the present invention makes it possible to perform a wastewater treatment with a high clarifying effect on a suspension, thereby contributing to prevention of water and environmental pollution.

Further, since the polymer flocculant can be produced by using a used polystyrene resin, it is possible to effectively use resources and reduce waste.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C09K 3/00 C09K 3/00 A

Claims (6)

[Claims] 1. A polymer flocculant comprising mainly a polymer compound and containing carbon black. 2. The polymer flocculant according to claim 1, wherein the polymer compound is a sulfonate of a polystyrene resin. 3. The polymer flocculant according to claim 1, wherein the polymer compound is a nonionic or anionic acrylamide resin. 4. The polymer flocculant according to claim 1, wherein the polymer compound is a cationic resin. 5. A wastewater treatment method comprising adding a polymer coagulant mainly containing a polymer compound and containing carbon black to a wastewater to thereby aggregate suspended substances and removing the aggregate by filtration. . 6. A polymer coagulant mainly composed of a polymer compound and carbon black are added to waste water,
A wastewater treatment method comprising aggregating suspended substances and removing aggregates by filtration.