JPH08141575A - Method and apparatus for treating wastewater - Google Patents

Abstract

PURPOSE: To remove stain components in wastewater as impurities and to purify the water to a dischargeable or recyclable level by adjusting pH of the wastewater in a specified condition while being agitated with constant agitation power within a specified range in the treatment of wastewater produced in degreasing, cleaning, etc., using a water base cleaning agent. CONSTITUTION: In a treatment apparatus 1 in which wastewater is treated in a condition in which a silicate expressed by a formula, (M2 O).(SiO2 )x (where, M is an alkali metal, 0.5<=x<=3.5) is present in a concentration of 400wt. ppm (as SiO2 ) or more, and also a nonionic surfactant exists, wastewater in a treatment tank 3 is agitated by an agitator 2 to form insoluble matters. The treated liquid from which the insoluble matters were separated by a filter bag 5 is introduced into a receiver tank 6 and discharged outside through a pipe 7. In this process, wastewater is agitated with constant agitation power in a range of 35-700W/m<3> , and pH is adjusted at 10 or below to separate and remove the insoluble matters formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various waste liquids generated in a washing process or a rinsing process, more specifically, in degreasing washing of a neutral or alkaline aqueous detergent containing a nonionic surfactant. The present invention relates to a processing method and a processing apparatus for processing the waste liquid economically and inexpensively.

[0002]

2. Description of the Related Art Regarding degreasing cleaning of an aqueous cleaning agent, a large amount of various components that pollute the water quality are contained in the waste liquid due to the components derived from the cleaning agent and the oil components derived from the object to be cleaned. . Typical pollutant components include chemical oxygen demand (hereinafter referred to as "COD") or biochemical oxygen demand (hereinafter referred to as "BOD"), substances measured with hexane extracts, heavy metal ions, phosphorus components, etc. Can be mentioned.

These pollutants have been removed by a coagulation method using aluminum or iron ions, ultrafiltration, or a method such as reverse osmosis. However, the COD component and the BOD component are not sufficiently removed by these coagulation methods and ultrafiltration, and the apparatus is complicated such as using pressure levitation in the separation step. Further, the method of reverse osmosis has a problem that a large amount of waste water cannot be treated by a small device.

In view of the problems of such conventional waste liquid treatment methods, the inventors of the present invention have proposed, as a waste liquid treatment method for collectively removing the above-mentioned components, a treatment method of forming an insoluble matter by aggregation. (Japanese Patent Application No. 6-131168).

[0005]

The treatment method by agglomeration has an advantage that the apparatus used in the conventional agglomeration method can be used as it is. Since the present invention more effectively implements the treatment method by the agglomeration, it is possible to efficiently remove the pollutants contained in the various waste liquids in a short time, and it is caused by the agglomeration of the pollutants. The treatment liquid after separating and removing the insoluble matter 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. It is intended to provide a waste liquid treatment method and a treatment device thereof, which are excellent in terms of effective use of resources and can be treated at low cost.

[0006]

In order to achieve the above object, the method for treating waste liquid according to the present invention has the following chemical formula (3) (wherein M represents an alkali metal and x is 0.5 ≦ x ≦ 3). .5
Is. ) 400wtppm (Si
The waste liquid, which is present at a concentration of at least O ₂ ) and in which a nonionic surfactant coexists, is stirred with a constant stirring power within the range of 35 to 700 W / m ³ , and the pH is 10 or less. Under the conditions, insoluble matter is formed, and then this insoluble matter is separated and removed.

[0007]

[Chemical Formula 3] (M ₂ O) · (SiO ₂ ) x

On the other hand, the waste liquid treating apparatus of the present invention used in the above-mentioned waste liquid treating method is represented by the following chemical formula (4)
Represents an alkali metal, and x is 0.5 ≦ x ≦ 3.5. ) 400 wtppm (SiO ₂
(Converted) or more, and a stirring mechanism for stirring the waste liquid in a state in which the nonionic surfactant coexists with a constant stirring power within the range of 35 to 700 W / m ³ , and the pH of the waste liquid. PH at which insoluble matter is formed under the condition of 10 or less
It is characterized by comprising a treatment tank having an adjusting mechanism and a separator for insoluble matter formed by stirring the waste liquid.

[0009]

[Chemical formula 4] (M ₂ O) · (SiO ₂ ) x

In the present invention, the type of the waste liquid to be treated is not particularly limited except that the concentration of silicate and the coexistence of the nonionic surfactant are required. Can include waste liquids produced after using various cleaning agents such as water-based cleaning agents and alkaline cleaning agents, and waste liquids containing specific amines and morpholines are also subject to this treatment. Is.

Further, the dirt component contained in the waste liquid is not particularly limited, but examples thereof include mineral oil such as quenching oil, oily cutting oil or drawing oil, complex oil such as rust preventive oil and water-based oil, petroleum-based oil such as kerosene. Solvent, chlorine solvent, flux, ink,
It is suitable for treating waste liquids containing higher fatty acids as soil components, especially waste liquids 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.

In the present invention, the silicate that should be present in the waste liquid is the silicate represented by the above chemical formula 4 (hereinafter simply referred to as "silicate"), and the alkali metal represented by M in the formula is sodium. , Potassium is preferable, and x in the formula is 0.5 ≦ x ≦ 3.5, and preferably 1 ≦ x ≦ 3.

The concentration of silicate in the waste liquid to be treated is 4
It is more than 00 wtppm, preferably 500-4
50,000 wtppm, and more preferably 1,0
It is from 00 to 5,000 wtppm. Concentration of silicate is 4
If it is less than 00 wtppm, the insoluble matter is not sufficiently formed and the degree of purification of the waste liquid is lowered. Also, 40,000 wt
If the concentration is excessively high, exceeding ppm, the silicate may not be uniformly dissolved, which is not economical.

When the waste liquid to be treated 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. Is to control the concentration by adding the required amount of silicate.

As means for allowing the silicate to exist in the waste liquid,
The silicate or its hydrate represented by the above chemical formula 4 may be added to the waste liquid. Specific examples of this silicate or its hydrate include potassium metasilicate, sodium metasilicate.
Hydrates, potassium disilicate monohydrate, water glass and the like can be mentioned, and these are conveniently handled as aqueous solutions. Further, when handled as a powder, a hydrate of a silicate is preferable because it has a particularly high dissolution rate.

The nonionic surfactant coexisting with the silicate in the waste liquid is not particularly limited. Examples of such a nonionic surfactant include those 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, and having 8 or less carbon atoms. Alkyl group, alkylphenyl group or alkenyl group, A is an alkylene group, and a plurality of A existing as repeating units
Are all acetylene groups, or at least one is an ethylene group and the rest are alkylene groups having 3 to 4 carbon atoms. ) It is desirable to allow an alkylene oxide adduct having an HLB of 8 to 18 (in the following chemical formula 5, n is the average number of moles of addition that gives an HLB of 8 to 18 to the alkylene oxide adduct) to coexist.

As described above, such an alkylene oxide adduct preferably has an HLB of 8 to 18, more preferably 9.5 to 16, and even more preferably 10 to 15.
Is. This alkylene oxide adduct has an HLB of 8
When the amount is less than the above, the insoluble matter is not sufficiently formed, and when the HLB is more than 18, the time for forming the insoluble matter becomes long and the treatment requires a long time.

[0018]

Embedded image R ₁ —O— (AO) n—R ₂

In the above chemical formula 5, the alkyl group of R ₁ and R ₂ in the formula, and the alkyl group and alkenyl group in the alkylphenyl group may be linear or branched.

Examples of the alkylene oxide adducts include polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, polyoxyalkylene alkyl phenyl ethers, polyalkylene glycol alkyl ether alkyl ethers,
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, benzyl ether of polyethylene glycol lauryl ether, and benzyl ether of polyethylene octyl phenyl ether. Among them, polyoxyethylene lauryl ether and polyoxyethylene nonylphenyl ether are preferable.

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

A suitable concentration of the nonionic surfactant containing the alkylene oxide adduct in the waste liquid is 5 to 5.
50,000 wtppm, more preferably 20 to 1
2,000 wtppm, more preferably 50 to 2.5
It is 00 wtppm. If this concentration becomes 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 the above-mentioned 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. It is preferable. Also,
When the waste liquid contains a stain component, it is desirable to add 0.1 to 10 parts by weight of the alkylene oxide adduct to 1 part by weight of the stain component. Especially, the concentration of coexisting alkylene oxide adduct is 50 to 2,500 wtpp.
Regarding the waste liquid of m, the silicate concentration in the waste liquid is 1,200 to 2,500 wtpp, regardless of the content of the components of the dirt.
By adding a silicate so as to have m, it is possible to process with excellent results without the need to control the concentration of the waste liquid.

In the waste liquid, together with the above-mentioned silicate and nonionic surfactant, the following chemical formula 6 (in the formula, R ₁ , R ₂ and R
₃ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group or a phenyl group, which may be the same or different. The same applies to a waste liquid containing a morpholine compound represented by the following formula (7) or an amine compound (7) (wherein R ₄ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms). Can be applied.

[0027]

[Chemical 6] [Margins below]

[0028]

[Chemical 7]

The amines represented by the above chemical formula 6 and the chemical formula 7
As specific examples of the morpholines represented by (hereinafter, these are collectively referred to as “specific amines”), ammonia,
Methylamine, ethylamine, isopropylamine, isobutylamine, amylamine, isoamylamine, hexylamine, octylamine, 2-ethylhexylamine, decylamine, dodecylamine, diethylamine, diisopropylamine, dibutylamine, diamylamine, trimethylamine, triethylamine, tripropylamine, Examples thereof include triisobutylamine, cyclohexylamine, dicyclohexylamine, aniline, benzylamine, diphenylamine, triphenylamine, morpholine, N-methylmorpholine and N-ethylmorpholine.

Preferably, R _{1 to} R shown in the above Chemical Formula 6 are used.
_At least one of _{3 is} a linear or branched alkyl group or cycloalkyl group having 5 to 20 carbon atoms,
Specifically, amylamine, isoamylamine, hexylamine, octylamine, 2-ethylhexylamine,
Examples include decylamine, dodecylamine, cyclohexylamine, dicyclohexylamine and the like. Also,
With respect to the morpholines represented by Chemical formula 7, R ⁴ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms because it is easily available, and specifically, N-methylmorpholine, N
-Ethylmorpholine and the like.

The concentration of the specific amines in the waste liquid to be treated is not particularly limited, but is preferably 500,000 wtppm or less. More preferably 100,000 wtpp
m or less, particularly preferably 12,500 wtppm or less. If the concentration is excessively high, the amount of silicate and nonionic surfactant present will be increased, or coagulation treatment in multiple stages will be required, which is not economical.

The waste liquid to be treated has a pH of 10 or less, preferably pH 1 to 9 in the presence of the silicate, the alkylene oxide adduct, other nonionic surfactants and, in some cases, the specific amines. More preferably, the pH is adjusted to 4 to 8.6, and then the insoluble matter can be effectively formed by stirring under constant stirring power.

The agitation of the waste liquid for forming the insoluble matter is carried out by subtracting the electric power (blank) consumed by the agitation in the absence of the waste liquid from the electric power per unit volume of the waste liquid consumed by the agitation of the waste liquid (hereinafter referred to as "blank"). This is referred to as "stirring power") under constant stirring power within the range of 35 to 700 W / m ³ , preferably 50 to 400 W.
/ M ³ . When stirring for forming the insoluble matter, if the stirring power is less than 35 W / m ³ , the insoluble matter is not sufficiently formed, and therefore the water quality of the treatment liquid is deteriorated. Further, if the stirring power is more than 700 W / m ^{3, the} insolubility of insoluble matter is poor, and the filtration rate is slow,
Foaming becomes large when the insoluble matter is formed, and it becomes difficult to process in a short time.

Such a waste liquid treatment method can be applied to both a batch type and a continuous type treatment method, but particularly, the equipment space and cost are reduced, and a high degree of waste liquid treatment is achieved by a simple method. In order to achieve this, it is preferable to use a batch system.

Specifically, when the silicates and the nonionic surfactant do not coexist in the waste liquid to be treated, the silicates represented by the chemical formula 4 and the nonionic surfactant represented by the chemical formula 5 are used. Add the agent and stir mix. When stirring,
The stirring power is not particularly limited, but the stirring and mixing can be smoothly carried out by performing the stirring power within the range of the stirring power. That is, if the stirring power is in the range of 35 to 700 W / m ³ , the liquid components can be stirred sufficiently uniformly in a short time of about 5 seconds to 2 minutes.

The acid component is added to the waste liquid in which the predetermined silicates and the nonionic surfactant coexist while stirring, and p
By setting H to 10 or less, an insoluble matter is formed, and in order to perform treatment by this, it is preferable to adjust the pH to 5 to 7.5 because the insoluble matter is formed at a high speed.

Furthermore, since the secondary adjustment described below is also used, it is particularly preferable to perform the primary adjustment to temporarily lower the pH of the solution to 2 to 4.5 because the insoluble matter is formed earliest. . When the phosphorus compound or the anionic surfactant is mixed in the waste liquid, calcium salts are added, but it is particularly preferable to add the calcium salt within the range of pH 2 to 4.5.

In the secondary adjustment, an alkali is added to adjust the pH to near neutrality of 5 to 7.5.
The time required for the adjustment (total processing time) is preferably a short time of 30 minutes or less. If this processing time is too short,
There is a possibility that the dehydration of the obtained insoluble matter and the water quality of the treatment liquid may deteriorate, and sufficient treatment liquid quality (waste liquid containing insoluble matter) cannot be obtained. If it is too long, there is a problem of treatment liquid quality. However, the amount of processing liquid that can be processed per hour is reduced, which is economically disadvantageous.

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 gas,
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 are 1 type or 2 types.
More than one species may be used.

Further, when treating the residual liquid after separating and removing the insoluble matter and discharging it, the use of hydrochloric acid, sulfuric acid, carbonic acid, sodium hydroxide, sodium hydrogencarbonate or the like as a regulator may appropriately contaminate the water quality. Can be prevented. At that time, if the waste liquid is a waste liquid after metal cleaning and is reused after processing, sulfuric acid and
It is desirable to use 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 preferable to adjust the pH of the waste liquid to exceed 10 to uniformly dissolve the silicate and then adjust the pH to 10 or less again. Is the way.

After the insoluble matter is formed in the waste liquid by adjusting the pH and stirring, the insoluble matter generated in the waste liquid is separated and removed by, for example, stationary separation, filtration, pressure floating separation, etc. Although separation can be carried out by a commonly known separation means, means such as filtration with a filter bag or stationary separation is optimal because it does not require a large-scale processing device. Also,
If desired, this treatment liquid can be subjected to a secondary treatment such as dilution, activated carbon adsorption, activated sludge or the like to obtain a higher treatment liquid. Furthermore, in order to highly process heavy metal ions,
There is no problem in using a commercially available metal scavenger together with an antifoaming agent for preventing foaming during treatment.

When treating the waste liquid of the present invention, it is essential that a certain concentration of silicate and nonionic surfactant coexist in the waste liquid. However, in the production of the waste liquid,
You may supply the waste liquid in which the silicate and the nonionic surfactant coexist in advance to the treatment tank, or separately supply the waste liquid to be treated, the silicate and the nonionic surfactant to the treatment tank. It may be used as a processing solution.

A batch type or continuous type processing apparatus is used as the processing apparatus used in the method for treating waste liquid of the present invention. Specific examples of the following processing apparatuses will be described with reference to the accompanying drawings. To explain.

FIG. 1 shows a batch type processing apparatus 1 according to the present invention. The processing apparatus 1 is a processing tank 3 for forming an insoluble matter while stirring the charged waste liquid with a stirrer 2. And a separator comprising a filter bag 5 for receiving the insoluble matter formed in the treatment tank 3 together with the waste liquid through the pipe 4 and separating the insoluble matter from the waste liquid. A receiving tank 6 for receiving the separated processing liquid and discharging the processing liquid to the outside through a pipe 7 is provided.

A effluent whose pH is adjusted to 10 or less is supplied to the treatment tank 3 in which a silicate having a specific concentration used in the method for treating the effluent of the present invention and a nonionic surfactant coexist. However, pipes for individually supplying the waste liquid, the silicates, the nonionic surfactant, the acid and the alkali may be arranged in the treatment tank, and predetermined conditions may be set in the treatment tank 3. In the figure, 8 is a pump provided in the pipe 7, and 9 is a pH sensor that constitutes a pH adjusting mechanism with the pipe for individually supplying the acid and the alkali.

In the processing apparatus 1, the stirring power of the stirrer 2 for stirring the waste liquid is set to a constant stirring power within the range of 35 to 700 W / m ³ , and the stirrer 3 is manually or predetermined. It is configured to be activated or deactivated by a simple control mechanism such as sequence control capable of controlling the state of the controlled object as a sequentially discontinuous state change in accordance with the set order or conditions.

Then, a waste liquid satisfying predetermined conditions is supplied to the treatment tank 3 by an appropriate means, an acid is added with stirring, and the pH sensor 9 is used to check the liquid property to temporarily put the liquid on the acidic side. A primary adjustment is performed to maintain the pH (4.5 or less). Next, add alkali to add waste liquid p
Adjusting H to near neutrality of 5 to 7.5 produces insoluble matter in the waste liquid by the secondary adjustment.

During the operation from the supply of the waste liquid to the treatment tank 3 to the formation of the insoluble matter during this period, the stirring power of the stirrer 2 is performed while keeping the rotation speed of the stirrer 2 constant.
The stirring power does not necessarily have to be within the range of 35 to 700 W / m ³ except for the step of forming the insoluble matter by adding the alkali. The stirrer 2 is started and stopped by turning the switch on and off.

FIG. 2 shows a continuous processing apparatus 10 in the processing apparatus of the present invention. The processing apparatus 10 has a first processing tank 12 and a first processing tank 12 which are divided into three by a partition wall for processing waste liquid. It comprises a processing tank 11 consisting of a second processing tank 13 and a third processing tank 14, and a separator consisting of a filter bag 15 for separating insoluble matter produced by the processing tank 11. A receiving tank 16 for receiving the treatment liquid from which the insoluble matter has been separated is attached.

Agitators 17, 1 for agitating the waste liquid in the first to third processing tanks 12, 13, 14 respectively.
8 and 19 are provided, and a supply pipe 2 for supplying a waste liquid to be treated to the first treatment tank 12
0, a supply pipe 21 for supplying silicates for keeping the concentration of silicate in the waste liquid constant, and a supply pipe 22 for supplying a nonionic surfactant, respectively. 13 is provided with an acid supply pipe 23 for once adjusting the pH of the waste liquid to be acidic, and the third treatment tank 14 is provided with an alkali supply pipe 24 for adjusting the waste liquid once adjusted to be neutral. ing.

Then, the waste liquid overflows from the first processing tank 12 and flows into the second processing tank 13 and then into the second processing tank 1.
The waste liquid of No. 3 overflows into the third processing tank 14, and the insoluble matter generated in the third processing tank 14 overflows with the waste liquid and flows into the filter bag 15 for continuous processing. ing. In the figure, 25 is an electric conductivity meter provided in the first processing tank 12, 26 and 27 are pH sensors provided in the second and third processing tanks 13 and 14, and 28 is a receiving tank 16. The discharge pipe for discharging the processing liquid inside is shown, and the acid supply pipe 23, the alkali supply pipe 24, and the pH sensors 26 and 27 are shown.
A pH adjusting mechanism is provided by such means.

A continuous type processing apparatus 10 having such a structure
Continuously supplies the waste liquid into the first treatment tank 12 through the supply pipe 20, and when a predetermined concentration of silicate or nonionic surfactant does not coexist in the waste liquid, the supply pipe 21, respectively. The waste liquid is stirred by the stirrer 17 while supplying the silicates and the nonionic surfactant through 22.

In the second treatment tank 13, the waste liquid overflowed from the first treatment tank 12 is received, and while the waste liquid is stirred by the stirrer 18, the acid is added from the acid supply pipe 23 to temporarily adjust the pH to 4.5 or less. Adjust to. Then,
In the third treatment tank 14, the waste liquid primarily adjusted as described above is received, and while stirring the waste liquid by the stirrer 19, alkali is added through the alkali supply pipe 24 to adjust the pH to 5 to 7.5 at the same time. , To produce insoluble matter.

The insoluble matter generated in the third processing tank 14 overflows together with the waste liquid and flows into the filter bag 1.
5, the filter bag 15 separates only the insoluble matter, and the treatment liquid is supplied to the receiving tank 16.
It is discharged to the outside through the discharge pipe 28.

In this continuous processing apparatus 10, the first
Stirrer 1 provided in the second treatment tank 12 and the second treatment tank 13
Although the stirring power of Nos. 7 and 18 is not limited at all, the stirring power of the stirrer 19 in the third treatment tank 14 for producing the insoluble matter is constant within the range of 35 to 700 W / m ³ as in the above-mentioned embodiment. It is driven by the stirring power of.

FIG. 3 and FIG. 4 show another mode of the stirring mechanism in the processing tank 3 of the batch type processing apparatus of FIG. A drain pipe 31 for temporarily taking out the internal waste liquid from the portion to the outside is provided, and the waste liquid taken out by the lead pipe 31 is again pumped through the supply pipe 33 via the pump 32.
The waste liquid is agitated by circulating it inside, but when the waste liquid is re-supplied to the processing tank 3, the waste liquid can be uniformly stirred by supplying the waste liquid along the tangential direction of the processing tank 3. The supply pipe 33 is arranged tangentially to the cylindrical processing tank 3.

[0058]

The method of treating waste liquid according to the present invention has a concentration of 400 wt.
When the pH of the waste liquid in which the silicate of ppm or more and the nonionic surfactant coexist is adjusted to 10 or less and the insoluble matter is generated in the waste liquid, the stirring power consumed for stirring the waste liquid is 35 to 700 W. By performing the stirring with a constant stirring power within the range of / m ³ , the SiO ₂ component and the nonionic surfactant react efficiently, and the nonionic surfactant, oil, and metal contained in the waste liquid are It is possible to accurately generate an insoluble matter including stain components such as phosphorus, phosphorus, and specific amines in a short time.

Further, the waste liquid treating apparatus of the present invention comprises a treatment tank for producing an insoluble matter by stirring the pH of the waste liquid in which a silicate having a concentration of 400 wtppm or more and a nonionic surfactant coexist and stirring the pH of the waste liquid to 10 or less. It is composed of a separator such as a filter bag for separating the generated insoluble matter from the waste liquid, and the stirring power for generating the insoluble matter in the treatment tank is within the range of 35 to 700 W / m ³ . Since the stirring is performed with constant stirring power, the insoluble matter can be effectively formed.

[0060]

EXAMPLES Hereinafter, the treatment of the waste liquid of the present invention will be described more specifically with reference to Examples and Comparative Examples. In these examples and comparative examples, the model waste liquid containing the oily stain component was processed by the batch type processing apparatus shown in FIG.

[Preparation of Model Waste Liquid] Oily soil components and other compounding components were added to water and heated to a temperature of 50 ° C., and the mixture was agitated and mixed with ultrasonic waves (50 KHz, 150 W) by an overhead stirrer for 30 minutes, A predetermined model waste liquid having the composition shown in Table 1 was prepared. These model waste liquids were diluted with water before use. [Margins below]

[0062]

[Table 1] * 1; Poeoxyethylene lauryl ether HLB = 13.1 * 2; Poeoxyethylene nonylphenyl ether HLB = 12.3 * 3; Poeoxyethylene nonylphenyl ether HLB = 3.3 * 4; Gulf Super Quench 70 Idemitsu Kosan Co., Ltd. ]

[Measurement of Stirring Power] The stirring power was measured by the power obtained by subtracting the power (blank) consumed by the stirring in the absence of the waste liquid from the power per unit volume of the waste liquid consumed by the stirring of the waste liquid. I asked.

Examples 1 to 11 and Comparative Examples 1 to 6 1) Various model waste liquids shown in Table 1 were put into the treatment tank 2 and stirred by the stirrer 3 with the stirring power shown in Table 2 to obtain Na metasilicate (9 25% aqueous solution of hydrate) was added in an amount shown in Table 2 and mixed by stirring for 1 minute. 2) While stirring the above liquid with the stirring power described in Table 2,
The pH was adjusted to 3 with 30% sulfuric acid or 3% sulfuric acid in 2 minutes. 3) Furthermore, while continuing stirring, the state of pH 3 was maintained for 1 minute, and 3% was adjusted to pH 6.5 in 2 minutes using caustic soda.
Was prepared. 1 from the time when pH becomes 5 or more
Stirring was continued for 0 minutes to form an insoluble matter, and stirring by the stirrer 3 was stopped. 4) Then, the liquid containing the insoluble matter was filtered through a filter bag (caliber 25 μ) 11 of the separation tank 10 and the filtration rate was observed. 5) Further, the filtrate after filtration was evaluated by COD _{M n} and hexane extract test (JIS K 0102). For Comparative Example 6, the pH of step (3)
Was stirred for 10 minutes from the time when the value became 5 or more, and 550 W / m ^{3 for} the first 2 minutes and 18 for the next 3 minutes.
5W / m ^3, the next 3 minutes 60 W / m ^3, the last 2 minutes 2
Stirring was stopped by applying a stirring power with a variable of 5 W / m ³ to form an insoluble matter. Other operations were the same. The results are shown in Table 2.

[0065]

[Table 2]

Examples 12 to 19 and Comparative Example 7 1) Using the treatment apparatus shown in FIG. 1, various model waste liquids shown in Table 1 were stirred at a stirring power of 150 W / m ³ to obtain metasilicic acid N.
a (9 hydrate) 25% aqueous solution, converted to SiO ₂ 15
00 ppm was added and mixed with stirring for 1 minute. 2) While stirring the above liquid with the same stirring power, use 30% sulfuric acid or 3% sulfuric acid to adjust the pH at T ₁ hour in Table 3 to Table 3
Prepared in X. When a phosphorus component coexists, after the addition of sulfuric acid is completed, a 20% aqueous solution of calcium chloride is added in an amount 30 times the mole of phosphorus in 1 minute. 3) Furthermore, while continuing stirring, the state of pH = X is shown in Table 3.
Holding the T ₂ hours, Table 3 of T ₃ with 3% sodium hydroxide
The pH was adjusted to Y in Table 3 by time. Stirring was continued from the time when the pH became 5 or more for T ₄ hours in Table 3 to form an insoluble matter, and the stirring was stopped. 4) Then, the mixture was filtered through the filder bag 11 (caliber 25 μm), and the filtration rate was observed. 5) Further, the filtrate after filtration was evaluated by COD _{M n} and hexane extract test (JIS K 0102).

Examples 20 to 22 1) Using the treatment apparatus shown in FIG. 1, various model waste liquids shown in Table 1 were stirred with a stirring power of 150 W / m ³ to obtain metasilicic acid N.
a (9 hydrate) 25% aqueous solution, converted to SiO ₂ 15
00 ppm was added and mixed with stirring for 1 minute. 2) While stirring the above liquid with the same stirring power, use 30% sulfuric acid or 3% sulfuric acid to adjust the pH at T ₁ hour in Table 3 to Table 3
Prepared in X. 3) Furthermore, stirring was continued with the same stirring power for T ₄ hours in Table 3 to form an insoluble matter, and then the stirring was stopped. 4) Then, the mixture was filtered through the filder bag 11 (caliber 25 μm), and the filtration rate was observed. 5) Further, the filtrate after filtration was evaluated by COD _{M n} and hexane extract test (JIS K 0102). The results of Examples 12 to 22 and Comparative Example 7 are also shown in Table 3.

[0068]

[Table 3]

[0069]

The method for treating waste liquid according to the present invention has a concentration of 40%.
The pH of the waste liquid in which 0 wtppm or more of silicate and the nonionic surfactant coexist is set to 10 or less, and when the insoluble matter is aggregated in the waste liquid by stirring, the stirring of the waste liquid is performed at 35 to 70.
Insoluble, including dirt components such as nonionic surfactants, oils, metals, phosphorus, and specific amines contained in the waste liquid, by carrying out under constant stirring power within the stirring power range of 0 W / m ^3. By forming a substance in a short time, various pollutants existing in the waste liquid can be effectively removed.

By adopting such a treatment method, for example, oils, carboxylic acids having 10 or more carbon atoms, morpholines, amines having 5 or more carbon atoms, silicon-based defoaming agents and the like having relatively strong hydrophobicity are used. Even when the components are contained, an insoluble matter is easily formed, and these components can be removed at the same time. 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 can be applied to high-concentration nonionic surfactant liquids in a short time, as compared with known treatment methods in which periron, a sulfuric acid band or activated clay is present. Insoluble matter can be formed in Further, since the stirring power of the processing device can be made constant, the device can be simplified, and at the same time, not only manual operation but also automatic operation by a simple mechanism is possible, which is advantageous in that the device can be manufactured at low cost. Have.

In the waste liquid treating apparatus of the present invention, the stirring for forming the insoluble matter in the waste liquid in the treatment tank can be performed with a constant stirring power within the stirring power range of 35 to 700 W / m ^3. Since it is configured so that the processing device can be operated easily and easily, and the waste liquid can be constantly stirred with a constant stirring power, it can be started and stopped by a simple computer control circuit. As compared with the conventional processing apparatus, the processing can be performed, which can greatly contribute to simplification of the apparatus, reduction of equipment cost, easiness of processing operation and labor saving of processing work.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a batch type processing apparatus in a processing apparatus for waste liquid according to the present invention.

FIG. 2 is an explanatory view showing an example of a continuous type processing apparatus in the processing apparatus for waste liquid according to the present invention.

FIG. 3 is a side view showing another example of the processing tank in FIG.

FIG. 4 is a plan view of the processing tank of FIG.

[Explanation of symbols]

 1,10 Waste liquid treatment device 2,17,18,19 Stirrer 3,11 Treatment tank 5,15 Filter bag 6,16 Receiving tank 9,26,27 pH sensor

Claims (3)

[Claims] 1. A silicate represented by the following chemical formula 1 (wherein, M represents an alkali metal, and x is 0.5 ≦ x ≦ 3.5) is 400 wtppm (converted to SiO ₂ ) or more. The waste liquid, which is present at a concentration and coexisting with the nonionic surfactant, is agitated with a constant agitation power within the range of 35 to 700 W / m ^{3 and} the pH is kept at 10 or less by stirring. A method for treating waste liquid, which comprises forming a dissolved substance, and then separating and removing this insoluble substance. [Chemical formula 1] (M ₂ O) ・ (SiO ₂ ) x 2. The treatment of the waste liquid according to claim 1, wherein the pH of the waste liquid is once set to 4.5 or less, and then the pH is adjusted to 5 to 7.5 to separate and remove the formed insoluble matter. Method. 3. A silicate represented by the following chemical formula 2 (wherein M represents an alkali metal and x is 0.5 ≦ x ≦ 3.5) having a content of 400 wtppm (SiO ₂ conversion) or more. A stirring mechanism that stirs the waste liquid that is present at a concentration and in which a nonionic surfactant coexists with a constant stirring power within the range of 35 to 700 W / m ³ , and the pH of the waste liquid is 10 or less. An apparatus for treating waste liquid, comprising: a treatment tank having a pH adjusting mechanism for forming an insoluble matter as described above; and a separator for the insoluble matter formed by stirring the waste fluid. [Chemical formula 2] (M ₂ O) · (SiO ₂ ) x