JPH0731984A - Treating method of waste liquid - Google Patents

Abstract

PURPOSE:To provide a simple and efficient treating method and to enable discharge or reuse in circulation of the remaining liq. after separation and removal by separating and removing the insoluble matter by making the condition in which a specified silicate is allowed to present in the waste liq. in a specified concn., and a nonionic surfactant is allowed to coexist, and pH is kept at <=10. CONSTITUTION:When the insoluble matter is formed by making the condition of the waste liq. in which the silicate expressed by the formula I is allowed to present in the concn. of >=400wt.ppm (expressed in terms of SiO2), and the nonionic surfactant is allowed to coexist, and moreover, pH is kept at <=10, the insoluble matter is separated and removed. In the formula I, M is alkali metal, (x) is 0.5<=x<=3.5. Since this waste liq. treating method forms the insoluble matter in a short time under the presence of extremely small amount of silicate as compared with a well-known method, for example, the method in which excess iron and alumina sulfate or activated clay are allowed to present, the amount of the insoluble matter to be separated from a treated waste liq. is small and disposal is very simple.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating various kinds of waste liquid, and more particularly to a method for treating waste liquid containing a nonionic surfactant.

[0002]

2. Description of the Related Art In recent years, a large number of water-based cleaning agents have been proposed as alternative substances to chlorine-based cleaning agents. Since such a water-based cleaning agent generates a large amount of waste liquid containing a surfactant, oil, etc. in the cleaning process and the rinsing process, a great deal of energy is consumed in the removal process.

In the waste liquid generated by using such an aqueous cleaning agent, various treatment methods such as reverse osmosis filtration, ultrafiltration, agglomeration with ferric chloride (hereinafter referred to as "periron") are adopted. ing. In the treatment of these waste liquids,
Regarding a waste liquid containing a nonionic surfactant, for example, a treatment method using a clay mineral is disclosed in JP-A-48-306.
Japanese Patent Laid-Open No. 95-136357, and Japanese Patent Laid-Open No. 51-136357 discloses a processing method using activated clay.

[0004]

The method for treating the waste liquid of the water-based cleaning agent generally requires a large-scale treatment device, its operation is complicated, and its treatment capacity is insufficient. There are various problems such as. Further, the above-mentioned Japanese Patent Application Laid-Open No. Sho 4 (1999) -39
No. 8-30695, and Japanese Patent Laid-Open No. 51-1363.
The treatment technology of No. 57 uses fine-grained compounds such as the clay minerals and activated clay, and therefore it is necessary to disperse these compounds uniformly in the waste liquid, which is inefficient or difficult to filter. There was a problem that it took time.

Further, regarding the waste liquid containing phosphorus, a means for removing phosphorus by a calcium salt is generally adopted. However, when non-ionic surfactants are contained in the waste liquid, it is practically difficult to collectively treat various pollution sources including these, and therefore individual treatment corresponding to the pollution sources is required. Therefore, there is a problem that the processing device becomes large-scale.

The inventors of the present invention, regarding the treatment of the various waste liquids described above, can remove various pollution sources collectively in a short time, the treatment method is simple and efficient, and the insoluble matter can be removed. The residual liquid after separation and removal can be purified to a level at which it can be discharged by performing a simple treatment if necessary, or it can be recycled and reused as it is. As a result of earnest research on a treatment method which is also excellent in terms of effective utilization of the above, the present invention has been completed.

[0007]

That is, according to the method for treating waste liquid of the present invention, the waste liquid is represented by the following chemical formula 4 (wherein M represents an alkali metal and x is 0.5≤x≤3.5). Is 400 wtppm (SiO ₂
It is present at a concentration equal to or higher than the above; the nonionic surfactant coexists, and the pH of the waste liquid is 10 or less to form an insoluble matter, which is separated and removed. It is characterized by that.

[0008]

[Chemical Formula 4] (M ₂ O) · (SiO ₂ ) _x

A more specific waste liquid suitable for the present invention is a nonionic surfactant represented by the following chemical formula 5 (wherein R ₁
Is an alkyl group having 6 to 30 carbon atoms, an alkylphenyl group or an alkenyl group, R ₂ is a hydrogen atom, an alkyl group having 8 or less carbon atoms, an alkylphenyl group or an alkenyl group, and A is an alkylene group and is present as a repeating unit. The plurality of A are all ethylene groups, or at least one is an ethylene group and the rest are alkylene groups having 3 to 4 carbon atoms. ) An alkylene oxide adduct having an HLB of 8 to 18 (in the following chemical formula 5, n is a chemical formula 5)
The alkylene oxide adduct represented by
It is the average number of added moles that gives LB. ) Coexist.

[0010]

Embedded image R ₁ —O— (AO) n—R ₂

In the waste liquid treatment method of the present invention, the kind of waste liquid to be treated is not particularly limited, but specifically, various cleaning agents such as an aqueous cleaning agent and an alkaline cleaning agent are used. Examples include waste liquid generated later.

[0012] Further, the stain component contained in the waste liquid is not particularly limited, but for example, mineral oil such as quenching oil, oily cutting oil or drawing oil, complex oil such as rust preventive oil and water-based oil, and kerosene. It is suitable for treating a waste liquid containing petroleum-based solvents, chlorine-based solvents, fluxes, inks, higher fatty acids and the like as a stain component, especially a waste liquid containing mineral oil. Further, with respect to the waste liquid containing phosphorus and the waste liquid containing metal, both phosphorus and metal contained in the waste liquid can be removed.

The silicate that should be present in the waste liquid is the above-mentioned chemical formula 4
In the silicate (hereinafter, simply referred to as “silicate”) represented by, the alkali metal represented by M in the formula is preferably sodium and potassium. Further, in the formula, x is 0.5 ≦ x ≦ 3.5, and preferably 1 ≦ x ≦ 3.

The concentration of silicate in the waste liquid to be treated is 400 w.
tppm or more, but preferably 500 to 40,000
0 wtppm, and more preferably 1,000 to
It is 5,000 wtppm. Concentration of silicate is 400w
If it is less than tppm, the insoluble matter is not sufficiently formed and the degree of purification of the waste liquid is lowered. Further, if the concentration is higher than 40,000 wtppm, the silicate may not be dissolved uniformly, which is not economical.

In the present invention, when the waste liquid to be treated already contains the above-mentioned concentration of silicate, it can be used as it is, but when it is insufficient in quantity or does not contain it at all. If not, the concentration is controlled by adding the required amount of silicate.

Means for allowing silicate to exist in the waste liquid includes
The silicate represented by Chemical Formula 4 or a hydrate thereof may be added to the waste liquid. Specific examples of the silicate or its hydrate include potassium metasilicate, sodium metasilicate nonahydrate, potassium disilicate monohydrate, and water glass. A hydrate of silicate is particularly preferable from the viewpoint of rapidity. The silicate or its hydrate is preferably added as an aqueous solution, but may be added in the form of powder.

The nonionic surfactant coexisting with the silicate in the waste liquid is not particularly limited, but the HLB represented by the chemical formula 5 is preferably 8-18, more preferably 9.5-16. Particularly preferred is an alkylene oxide adduct of 10 to 15. If the HLB of this alkylene oxide adduct is less than 8, insoluble matter is not formed, and
If the HLB exceeds 18, the insoluble matter formation time becomes long and the treatment requires a long time. In the formula (5), R ₁ is an alkyl group having 6 to 30 carbon atoms, an alkylphenyl group or an alkenyl group, and the carbon number of these is preferably 10 to 22. Further, in the formula of Chemical formula 5, R ₂ is a hydrogen atom, an alkyl group having 8 or less carbon atoms, an alkylphenyl group or an alkenyl group, and among them, a hydrogen atom is the most preferable, and an alkyl group and an alkylphenyl group are Followed by this. In addition, the alkyl group of R ₁ and R ₂ , the alkyl group and the alkenyl group in the alkylphenyl group,
It may be linear or branched.

Examples of the alkylene oxide adduct include polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyalkylene alkyl phenyl ether, polyalkylene glycol alkyl ether alkyl ether,
Examples thereof include alkylphenyl ethers of polyalkylene glycol alkyl ethers, alkyl ethers of polyalkylene glycol alkylphenyl ethers, and alkylphenyl ethers of polyalkylene glycol alkylphenyl ethers.

More specifically, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether,
Examples thereof include polyoxyethylene nonyl phenyl ether, polyoxy (propylene / ethylene) lauryl ether, polyethylene glycol lauryl ether benzyl ether, and polyethylene octyl phenyl ether benzyl ether. Among them, polyoxyethylene lauryl ether and polyoxyethylene nonylphenyl ether are preferable.

Other nonionic surfactants include polyoxyalkylene sorbitan stearate such as polyoxyethylene sorbitan stearate.

The preferred concentration of the nonionic surfactant containing the alkylene oxide adduct in the waste liquid is 5 to 5.
It is 0000 wtppm. More preferably 20 to 1
2,000 wtppm, particularly preferably 50 to
It is 2,500 wtppm. If this concentration is too high, it is necessary to increase the amount of silicates present, which is not economical. When the waste liquid to be treated already contains a nonionic surfactant such as an alkylene oxide adduct, it can be used as it is, and the waste liquid not containing it is added separately.

In treating the waste liquid, in order to purify the waste liquid after separating and removing the formed insoluble matter to a level at which the waste liquid can be discharged, a silicate is present in an amount of about 1 to 10 times by weight with respect to the alkylene oxide adduct. Preferably. When the waste liquid contains a soil component, 0.1 to 1 part of the alkylene oxide adduct is added to 1 part by weight of the soil component.
It is desirable that 0 part by weight be present. Particularly, the concentration of coexisting alkylene oxide adduct is 50 to 2,500 w.
Regarding the waste liquid of tppm, the concentration of silicate in the waste liquid is 1,200 to 2,500 wtp regardless of the content of dirt.
By adding the silicate so as to have pm, it is possible to perform the treatment with excellent results without the need to control the concentration of the waste liquid.

The waste liquid to be treated has a hydrogen ion concentration of pH 10 or less, preferably pH 1 in the presence of a silicate and an alkylene oxide adduct or other nonionic surfactant.
-9, more preferably pH 4 to 8.6, the insoluble matter can be effectively formed. In addition,
If the pH of the waste liquid exceeds 10, the insoluble matter cannot be effectively formed. Further, when the concentration of the alkylene oxide adduct in the waste liquid is 50 to 2,500 wtppm or less, the pH of the insoluble matter formation reaction is remarkably increased by adjusting the pH to 4 to 8.6.

In adjusting the pH of the waste liquid, the pH of the waste liquid is once adjusted to 4.5 or less, particularly 2 to 4 with an acid.
By adding alkali to adjust the pH to 6 to 7.5,
In particular, the cohesiveness of the insoluble matter is improved and the separation efficiency is further improved. The pH adjustment by this method is effective regardless of the type of the waste liquid, but particularly it exhibits an excellent ability to treat the waste liquid containing phosphorus ions and metals.

There is no limitation on the adjusting agent for adjusting the pH of the waste liquid, but as the acid, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, benzoic acid, formic acid, carbonated water, carbon dioxide, calcium chloride, etc. Can be mentioned. Examples of the alkali include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, monoethanolamine, triethanolamine and ammonia. These acids or alkalis may be used alone or in combination of two or more. When treating and discharging the residual liquid after separating and removing the insoluble matter, it is possible to prevent water pollution by appropriately using hydrochloric acid, sulfuric acid, sodium hydroxide, sodium hydrogen carbonate as a regulator. .
Further, when the waste liquid is a waste liquid after metal cleaning or the like and is reused after the treatment, it is desirable to use sulfuric acid, which is less likely to cause a corrosion factor, or phosphoric acid or benzoic acid which has an anticorrosion effect. Further, in order to allow the silicate to uniformly exist in the waste liquid, it is also desirable that the pH of the waste liquid is adjusted to 10 or more to dissolve the silicate uniformly, and then the pH of the waste liquid is adjusted to 10 or less again. Is.

When the waste liquid to be treated contains a metal, the metal in the waste liquid reacts with the silicate to form an insoluble matter, so that this metal can be removed together with the dirt component. is there. Metals that can be processed include iron, copper,
Although there are chromium, zinc, aluminum, nickel, manganese, etc., a commercially available metal ion scavenger can be used together when removing these metals.

In addition, tripolyphosphoric acid, pyrophosphoric acid,
When phosphorus compounds such as phosphoric acid and phosphorous acid are contained, coexistence of calcium ions in the waste liquid causes phosphorus ions and calcium ions to react with each other to form an insoluble matter. Phosphorus can also be removed. In this case, the amount of calcium ions coexisting in the waste liquid is preferably at least twice the molar ratio of phosphorus ions, preferably 5 to 100 times, more preferably 10 to 50 times.
Double. When the amount of calcium ions is too small, the phosphorus ions are not sufficiently removed, and an excessive amount thereof is economically disadvantageous, and it is difficult to remove the insoluble matter. In order to allow calcium ions to coexist in the waste liquid, it may be supplied as a calcium salt. Such calcium salt may be water-soluble, and examples thereof include calcium chloride, calcium chloride / dihydrate, calcium hydroxide and calcium nitrate. This calcium ion may be initially contained in the waste liquid, but a calcium salt may be added during the pH adjustment of the waste liquid to be treated. The calcium salt may be added as a powder, but it is more preferable to add it as an aqueous solution.

The waste liquid thus treated is further subjected to p treatment if it is necessary to carry out a secondary treatment after removing the insoluble matter.
It is preferable to adjust H. For example, when the treated water is discharged or treated with activated sludge or the like to further purify the waste liquid, it is preferable that the residual liquid has a pH of 5.8 to 8.6. Further, in the treatment by activated carbon, ozonolysis, etc., it is preferable to readjust the pH to 2.0 to 11 and perform the secondary treatment depending on its properties.

In the secondary treatment, a polymer flocculant or the like can be present in the waste liquid as needed, and it does not matter if an anionic surfactant or a builder is present in the waste liquid. For the formation of the insoluble matter, an extremely insoluble matter can be formed in a short time of about 5 to 30 minutes by means such as stirring the waste liquid as necessary. Further, even in the stirring operation, sufficient processing can be performed by stirring at a constant speed, so that the processing apparatus can be simplified. In addition, the method for separating and removing the insoluble matter generated in the waste liquid is, for example, static separation, filtration, pressure floating separation, or the like, which is generally known separation means, such as filtration by a filter bag or static separation. It is optimal because it allows the coagulation and separation of substances and does not require a large-scale processing device.

[0030]

The method for treating waste liquid according to the present invention is 400 wtpp
By adjusting the pH of the waste liquid in which the silicate having a particle size of m or more and the nonionic surfactant, preferably the alkylene oxide adduct represented by Chemical formula 5 coexist, to 10 or less, SiO ₂
The components and the nonionic surfactant react with each other to form an insoluble matter containing oil, metal, phosphorus and other contaminants contained in the waste liquid. As a result, insoluble matter is easily formed even when the waste liquid contains oil, a carboxylic acid having 10 or more carbon atoms, and other relatively hydrophobic components. Further, by allowing calcium ions to coexist in the waste liquid, it is possible to simultaneously remove the phosphorus component mixed in the waste liquid.

The waste liquid treatment method of the present invention is insoluble in a short time in the presence of an extremely small amount of silicate, as compared with conventionally known treatment methods in which, for example, periron, a sulfuric acid band or activated clay is present. Therefore, the amount of the insoluble matter separated from the treatment waste liquid is small, and the disposal of the insoluble matter is very easy.

The waste liquid treated by the treatment method of the present invention contains almost no nonionic surfactant or stain component in the residual liquid after the insoluble matter is separated and removed. Therefore,
If necessary, the residual liquid can be discharged by using a simple method such as dilution, sand filtration, activated carbon adsorption, and activated sludge treatment together. Furthermore, the residual liquid can be directly reused as a cleaning liquid or a rinse liquid, and the amount of waste liquid can be greatly reduced.

When a conventionally known flocculation method is used, for example, when using excess iron or activated clay, chlorine ions derived from excess iron or Al ions derived from activated clay are mixed in the residual liquid,
It becomes difficult to reuse it as a cleaning liquid or a rinse liquid. However, according to the waste liquid treatment method of the present invention, for example, when the treatment waste liquid is generated by the use of an alkaline cleaner, even if the residual liquid obtained by separating and removing the insoluble matter contains silicate, It is possible to reuse it as an alkaline cleaner containing. The insoluble matter separated from the treatment waste liquid may be recovered or, if necessary, dissolved in an organic solvent such as methylene chloride or ethyl acetate and appropriately treated.

[0034]

EXAMPLES Hereinafter, the method for treating waste liquid according to the present invention will be described more specifically with reference to Examples and Comparative Examples.

Examples 1 to 14 and Comparative Examples 1 to 7 [Preparation of model waste liquid] Oily soil components and other compounding ingredients were added to water and heated to a temperature of 50 ° C., and ultrasonic waves (65 KH) were applied.
(z, 150 W), and stirred and mixed for 30 minutes with an overhead stirrer to prepare predetermined model waste liquids having the compositions shown in Table 1, respectively. These model effluents were used as the undiluted solution or diluted.

[Method for Testing Waste Liquid Treatment] (1) Various silicates or other additives shown in Table 2 were added to various model waste liquids shown in Table 1 and mixed with stirring. (2) While stirring the model waste liquid at a stirring speed of about 300 rpm, use 30% sulfuric acid or 3% sulfuric acid to adjust the pH to 7
Neutralized. (3) After neutralization, an insoluble matter was formed while stirring at a stirring speed of about 30 rpm for 20 minutes. (4) Then, No. 5A filter paper (manufactured by Toyo Roshi Kaisha, Ltd.) was used for filtration at normal pressure, and the filtration rate was observed. (5) Further, the filtrate after filtration was evaluated by a methylene chloride extract test. The methylene chloride extract test was conducted as follows. 1) An appropriate amount of the filtrate was placed in a separating funnel and adjusted to pH <2 with (1 + 3) sulfuric acid. 2) Methylene chloride was added, and the methylene chloride extraction operation with vigorous shaking was performed twice to separate the methylene chloride layer. 3) To the separated methylene chloride layer, an equal amount of n-hexane and a small amount of anhydrous sodium sulfate were added to remove water. 4) The separated liquid was transferred to an evaporation dish, the organic solvent was volatilized at a temperature of 80 ° C., and the weight of the residue was measured. The results are shown in Table 2.

The results obtained by performing the same operation without using silicate are shown as blanks, when the amount of silicate added is less than the required amount, when other sedimentation means is used, and the stationary separation means is used. The above is also shown as a comparative example.

Examples 15 to 28 and Comparative Example 8 [Test method for waste liquid treatment] (1) A table in which various surfactants and various silicates shown in Table 3 were blended without mixing the oily soil component and the like. Of the model solutions of Example 3, the model solutions of Examples 15 to 17 were adjusted to pH 7 with 30% sulfuric acid or 3% sulfuric acid while stirring at a stirring speed of about 300 rpm, and 30 r for 20 minutes.
The insoluble material was formed while stirring at a stirring speed of pm. (2) With respect to the model liquids of Examples 18 to 28, the pH was adjusted to 3 using 30% sulfuric acid or 3% sulfuric acid while stirring at a stirring speed of about 300 rpm, and after 1 minute, the stirring speed was about 300 rpm. The pH was adjusted to 6.5 with a 4% sodium hydroxide aqueous solution or a 1% sodium hydroxide aqueous solution while stirring at 2, and an insoluble matter was formed while stirring at a stirring speed of 300 rpm for 7 minutes. (3) For the model liquid of Comparative Example 8 in which a sulfuric acid band was used as an additive, pH was adjusted using 30% sulfuric acid or 3% sulfuric acid while stirring at a stirring speed of about 300 rpm.
After neutralizing to 7, insoluble matter was formed while stirring at a stirring speed of about 30 rpm for 20 minutes. (4) Regarding each of the insoluble matter forming liquids of (1), (2) and (3), No. 5A filter paper (manufactured by Toyo Roshi Kaisha, Ltd.) was used for filtration at normal pressure, and the filtration rate was observed. (5) In addition, the COD _{M n} test (J
IS K0102) was performed. The results are shown in Table 3 together with the case of blank without silicate. In Comparative Example 8 using the sulfuric acid band, CO
D _{M n} is only slightly reduced. In addition, Example 28 in Table 3 was obtained by stirring for 7 minutes using a nonionic surfactant having an HLB of more than 18 and then allowing the mixture to stand still for 6 hours, and again filtering in the same manner as in (4). Is shown.

Examples 29 to 37 [Preparation of model waste liquid] The compounding components shown in Table 4 in which phosphorus compounds and oily substances were compounded as various stain components were added to water and the temperature was adjusted to 50.
The mixture was heated to 0 ° C. and mixed with ultrasonic waves (65 KHz, 150 W) for 30 minutes with an overhead stirrer to prepare predetermined model waste liquids. These model waste liquids were used as they were, or after being diluted.

[Waste liquid treatment test method] 1) To various model waste liquids shown in Table 4, the silicates shown in Table 5 were added as an additive and mixed by stirring, and the following operation method α or operation method β was used as an operation method. An insoluble material was formed. (Operation Method α) The model waste liquid was adjusted to pH 5.5 with 30% sulfuric acid or 3% sulfuric acid while stirring at a stirring speed of about 300 rpm. After 1 minute, the additive in Table 5 (calcium chloride) was added, and for another 7 minutes, about 300 rpm.
The insoluble matter was formed while stirring at a stirring speed of. (Operation Method β) The model waste liquid was adjusted to pH 3 with 30% sulfuric acid or 3% sulfuric acid while stirring at a stirring speed of about 300 rpm. After 1 minute, the additive (calcium chloride) in Table 5 was added, and the mixture was further stirred for 1 minute at a stirring speed of about 300 rpm. Further, the pH was adjusted to 6.5 with a 4% aqueous sodium hydroxide solution or a 1% aqueous sodium hydroxide solution, and then an insoluble matter was formed while stirring at a stirring speed of about 300 rpm for 7 minutes. 2) For each liquid thus obtained, No. 5A filter paper (manufactured by Toyo Roshi Kaisha, Ltd.) was used for filtration at normal pressure, and the filtration rate was observed. 3) The filtrate after filtration was also evaluated by quantitative determination of COD _{M n} and phosphorus and methylene chloride extract test. The results are shown in Table 5. The amount of phosphorus was determined by ICP emission analysis.

Examples 38 to 44 [Preparation of model waste liquid] The components in Table 6 containing various stain components were heated to a temperature of 50 ° C and subjected to ultrasonic waves (65 KH).
(z, 150 W), the mixture was stirred and mixed for 30 minutes with an overhead stirrer to prepare predetermined model waste liquids. These model waste solutions were used as stock solutions or diluted.

[Waste liquid treatment test method] 1) Various model waste liquids shown in Table 6 were added with various additives such as silicates shown in Table 7 and mixed with stirring. 2) The model waste liquid was neutralized to pH 7 with 30% sulfuric acid or 3% sulfuric acid while stirring at a stirring speed of about 300 rpm. 3) After neutralization, an insoluble matter was formed while stirring at a stirring speed of about 30 rpm for 20 minutes. 4) Then, No. 5A filter paper (manufactured by Toyo Roshi Kaisha, Ltd.) was used for filtration at normal pressure, and the filtration rate was observed. 5) Further, the filtrate after filtration was evaluated by the COD _{M n} methylene chloride extract test, the content of copper and iron, and the like. The results are shown in Table 7.

Examples 45 to 50 and Comparative Examples 9 to 11 [Preparation of model waste liquid] Various chlorine-based solvents as soil components were mixed with water as shown in Table 8 and heated to a temperature of 50 ° C.
Ultrasonic waves (65 KHz, 150 W) were agitated and mixed for 30 minutes with an overhead stirrer to prepare predetermined model waste liquids. These model waste solutions were diluted and used.

[Test Method for Waste Liquid Treatment] 1) The silicates shown in Table 9 were added as additives to various model waste liquids shown in Table 8 and mixed with stirring to form insoluble matters. 2) While stirring the above model waste liquid at a stirring speed of about 300 rpm, 30% sulfuric acid or 3% sulfuric acid was used to adjust the pH to 3
Adjusted to. The mixture was stirred for 1 minute at a stirring speed of about 300 rpm. Further, the pH was adjusted to 6.5 with a 4% aqueous sodium hydroxide solution or a 1% aqueous sodium hydroxide solution, and an insoluble matter was formed while stirring at a stirring speed of about 300 rpm for 7 minutes. 3) Then, No. 5A filter paper (manufactured by Toyo Roshi Kaisha, Ltd.) was used for filtration at normal pressure, and the filtration rate was observed. The filtrate after this filtration was tested by the following operation method γ and operation method δ. (Operation method γ) The amount of chlorine-based solvent contained in the filtrate after filtration was measured by the headspace method. The results are shown in Table 9. (Operation method δ) After air was blown into 300 ml of the filtrate after filtration for 5 minutes at a flow rate of 5 l / min, the content of the chlorine-based solvent was measured by the headspace method. Table 9 shows the situation when air was blown in and the measurement result of the residual amount of the chlorine-based solvent by this operation method δ. As a comparative example, a model waste liquid containing no silicate was tested by the following operating method ε. (Operation Method ε) After blowing air into 300 ml of various model waste liquids shown in Table 8 themselves at a flow rate of 5 liters / minute for 5 minutes, the content of the chlorine-based solvent was measured by the headspace method. Table 9 shows the situation when the air was blown in and the measurement results of the residual amount of the chlorine-based solvent.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

[Table 5]

[0050]

[Table 6]

[0051]

[Table 7]

[0052]

[Table 8]

[0053]

[Table 9]

[0054]

The method for treating waste liquid according to the present invention is 400 w.
By adjusting the pH of the waste liquid in which the silicate of tppm or more and the nonionic surfactant, preferably the alkylene oxide adduct represented by the above chemical formula 5 coexist, to 10 or less, S
The iO ₂ component reacts with the nonionic surfactant to form insoluble matter such as oil, metal, and phosphorus contaminants contained in the waste fluid, so the waste fluid can be simply removed by separating and removing this insoluble matter. And can be easily processed. In particular, even when the waste liquid contains a relatively highly hydrophobic component such as oil or a carboxylic acid having 10 or more carbon atoms, an insoluble matter is easily formed, and a calcium salt is allowed to coexist in the waste liquid. As a result, the phosphorus component can be removed at the same time.

Further, according to the waste liquid treatment method of the present invention, insoluble matter is formed in a short time in the presence of a small amount of silicate, so that the amount of insoluble matter separated from the treated waste fluid is small and the insoluble matter is insoluble. Very easy to dispose of. In addition, since the waste liquid after being treated by the treatment method of the present invention contains almost no nonionic surfactant or stain component, it may be diluted, sand filtered, activated carbon adsorbed, activated sludge treated, etc. if necessary. It can be released by treating it in a simple manner. Furthermore, the treated waste liquid can be directly reused as a cleaning liquid or a rinse liquid, and the amount of waste liquid can be significantly reduced.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Hayashi 575-1 Nakajima, Kawauchi-cho, Tokushima-shi, Tokushima Toagoi Chemical Industry Co., Ltd. Tokushima factory

Claims (4)

[Claims] 1. The following chemical formula 1 in the waste liquid (wherein, M represents an alkali metal, and x is 0.5 ≦ x ≦ 3.5).
Is 400wtppm (SiO ₂ conversion)
It is characterized in that the insoluble matter is formed at the above concentration, the nonionic surfactant coexists, and the pH of the waste liquid is 10 or less to form an insoluble matter, which is separated and removed. Waste liquid treatment method. [Chemical formula 1] (M ₂ O) · (SiO ₂ ) _x 2. The following chemical formula 2 in the waste liquid (wherein M represents an alkali metal and x is 0.5 ≦ x ≦ 3.5).
Is 400wtppm (SiO ₂ conversion)
It is present in the above concentration and serves as a nonionic surfactant as shown in the following chemical formula 3 (wherein R ₁ is an alkyl group having 6 to 30 carbon atoms, an alkylphenyl group or an alkenyl group, and R ₂ is a hydrogen atom or a carbon atom). An alkyl group, an alkylphenyl group or an alkenyl group having a number of 8 or less, A is an alkylene group, and a plurality of A existing as a repeating unit are all ethylene groups, or at least one is an ethylene group, The rest is an alkylene group having 8 to 18 HLB represented by an alkylene group having 3 to 4 carbon atoms (in the following chemical formula 3, n is an average addition mole giving an HLB of 8 to 18 to the alkylene oxide adduct). It is a number.)
And the pH of the waste liquid is 10 or less, insoluble matter is formed, and the insoluble matter is separated and removed. Embedded image (M ₂ O). (SiO ₂ ) _x embedded image R ₁ —O— (AO) n—R ₂ 3. The treatment of the waste liquid according to claim 1 or 2, wherein the pH of the waste liquid is once set to 4.5 or lower, and then the pH is adjusted to 6 to 7.5 to separate and remove the insoluble matter produced. Method. 4. The phosphorus ions are present in the waste liquid, and the calcium ions are coexistent therein.
4. The method for treating waste liquid according to any one of 3 above.