JPH0663534A - Method for removing contaminant from waste cleaning water - Google Patents

Abstract

PURPOSE:To easily separate and remove a nonionic surfactant along with the contaminant in a waste cleaning soln. generated when a material is cleaned by a cleaner contg. the surfactant by heating the waste soln. above the cloud point of the surfactant. CONSTITUTION:A material is cleaned with a cleaner composition consisting of a nonionic surfactant alone or a mixture of the nonionic surfactant and ionic surfactant. When the waste cleaning soln. is discharged into the river or sewerage, the nonionic surfactant is previously separated and removed along with the contaminant. In this case, the waste soln. is heated above the cloud point of the surfactant, and a porous body, especially an org. porous material consisting of the polysaccharide fibrous material contg. a cellulosic fibrous material, is mixed into the waste soln. to effectively separate and remove the materials. The porous body after having adsorbed the contaminant is incinerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning waste liquid purification method, and more particularly to a method for removing soil components from a cleaning waste liquid containing a nonionic surfactant.

[0002]

2. Description of the Related Art In recent years, nonionic surfactants have been incorporated into detergent compositions to be used not only in various industrial fields such as the field of textiles and metalworking, but also in general households.
Huge amount is consumed. Cleaning wastewater generated industrially is required to be purified before being discharged into rivers and sewers due to various wastewater regulations. In the industrial world, the burden of the purification treatment cost of this cleaning waste liquid is increasing year by year. On the other hand, in general households, the drainage from washing and dishwashing is discharged into rivers and sewers without any treatment.

[0003]

It is difficult to remove the nonionic surfactant by the current waste liquid treatment with activated sludge. Therefore, the present invention relates to a cleaning waste liquid containing a nonionic surfactant, and more specifically, a cleaning part comprising a nonionic surfactant alone or a mixture of a nonionic surfactant and an ionic surfactant. It is an object of the present invention to provide a method capable of easily separating and removing a soil component in a cleaning waste liquid generated by cleaning with an agent composition together with a nonionic surfactant without a large burden. And

[0004]

Means for Solving the Problems The inventor has keenly sought a method capable of easily removing and purifying dirt components from a cleaning waste liquid washed with a surfactant containing a nonionic surfactant by a simple method. Researched. As a result, if a porous material is allowed to coexist in the cleaning waste liquid as needed and the cleaning waste liquid is heated above the cloud point of the nonionic surfactant, the dirt components from the cleaning waste liquid are nonionic. It was discovered that it can be separated and removed together with a surfactant.

Therefore, in the method for removing soil components from a cleaning waste liquid according to the present invention, the surfactant portion comprises a nonionic surfactant alone or a mixture of a nonionic surfactant and an ionic surfactant. It is characterized in that a cleaning waste liquid generated by cleaning with the cleaning composition is heated to a temperature not lower than the cloud point of the nonionic surfactant. According to the method for removing the dirt component from the cleaning waste liquid according to the present invention,
When the cleaning waste liquid is heated above the cloud point of the nonionic surfactant, it is preferable to allow a porous body to coexist in the cleaning waste liquid. Examples of such a porous body include organic porous substances such as polysaccharide-based fibrous substances containing cellulose-based fibrous substances.

The nonionic surfactant constituting the detergent portion of the detergent composition is, for example, alcohol ethoxylate or alkylphenol ethoxylate. These nonionic surfactants may be used alone or as a mixture of two or more kinds. In the cleaning waste liquid purified by the method of the present invention, the cleaning agent portion of the cleaning composition may consist of the nonionic surfactant alone, but the nonionic surfactant and the ionic surfactant It may be a mixture with an agent. Examples of such an ionic surfactant include anionic surfactants such as alkylbenzene sulfonate, α-olefin sulfonate, alkyl sulfonate, higher alcohol sulfate ester salt, alkyl trimethyl ammonium chloride, and dialkyl dimethyl. Examples thereof include cationic surfactants such as ammonium chloride and zwitterionic surfactants such as alkyldimethylaminoacetic acid bedine.

The nonionic surfactant contained in the cleaning waste liquid purified by the method of the present invention is not limited to those having a specific cloud point. However, regarding the cloud point of the nonionic surfactant used, it is desirable to consider the following points. The washing needs to be performed below the cloud point of the nonionic surfactant in order to prevent precipitation of the nonionic surfactant. Therefore, if the cloud point is too low, it may be inconvenient during cleaning. Further, in the waste liquid purification method of the present invention, it is necessary to heat the cleaning waste liquid above the cloud point of the nonionic surfactant in order to separate and remove the dirt component. Therefore, if the cloud point is too high, heating requires a lot of energy, which is not economical. Considering the above, the cloud point is 20 ° C or higher 1
The temperature is 00 ° C or lower, preferably 30 ° C or higher and 90 ° C or lower, and more preferably 35 ° C or higher and 80 ° C or lower.

From the above cloud point range, a nonionic surfactant having a cloud point at a temperature higher than the cleaning temperature may be appropriately selected according to the temperature for cleaning. When the cleaning waste liquid is heated above the cloud point of the nonionic surfactant, it is preferable to separate the object to be cleaned from the cleaning waste liquid. This is because by separating the object to be cleaned and the cleaning waste liquid, recontamination of the object to be cleaned with a soil component is prevented.

When the cleaning waste liquid is heated above the cloud point, the cleaning waste liquid is allowed to coexist with a porous body, particularly an organic porous substance such as a polysaccharide fibrous substance containing a cellulose fibrous substance. Then, the dirt component is more effectively separated and removed. The reason for this is not clear, but it is considered that these substances have a strong adsorptive power to the nonionic surfactant deposited together with the soil component. The porous body, particularly the polysaccharide-based fibrous material containing the cellulose-based fibrous material, can be incinerated as it is after adsorbing the dirt component.

The cleaning waste liquid from which the dirt components have been separated / removed may be treated as waste water, or can be used again for cleaning. When the detergent composition used for washing contains an ionic surfactant, this ionic surfactant is not simultaneously removed during the separation / removal of the soil component. Therefore, when using the purified waste liquid for cleaning again,
There is no need to add a new ionic surfactant,
It is economical because it can be added in small amounts.

On the other hand, since the nonionic surfactant is separated and removed from the waste liquid together with the dirt component by separating and removing the dirt component, it is necessary to add a new one when the cleaning-treated waste liquid is used for cleaning again. However, in the current sewage treatment facility using activated sludge, it is difficult and problematic to remove nonionic surfactants, so
When the wastewater from which the dirt component has been separated and removed by the method of the present invention is discharged as sewage, it leads to a reduction in COD of wastewater from a sewage treatment facility to a river or the like.

Examples of the stain component here include oil stains and mud stains, but are not particularly limited. Examples of oil stains include mineral oils such as machine oils, vegetable oils such as tempura oil, and animal oils such as lipids and fats of gravy produced by the human body.

[0013]

When the cleaning waste liquid is heated above the cloud point of the nonionic surfactant, the hydrophilicity of the nonionic surfactant decreases,
Nonionic surfactant separates from the wash effluent. Therefore, the dirt component can be separated and removed together with the nonionic surfactant. Furthermore, by coexisting with a porous material such as an organic porous material made of a polysaccharide fibrous material containing a cellulose fibrous material, separation and removal can be further effectively performed.

[0014]

EXAMPLES Examples of the cleaning waste liquid purification method according to the present invention will be described below, but the scope of the present invention is not limited to these examples. In this example, the effect was observed under the test conditions in which the nonionic surfactant was easily solubilized and separation / removal was more difficult.

As a stain component, 100 parts by weight of liquid paraffin (Wako Pure Chemical Industries, Ltd. reagent grade 1) was added to oil-soluble paint Sudan II (1- (2,4-dimethylphenylazo) -2).
-Naphthol. Wako Pure Chemical Industries, Ltd. special grade reagent) 3.
What melt | dissolved 6 weight part was used. Sudan II has 49
The maximum absorption wavelength was shown in visible light with a wavelength of 0 nm, and the absorbance at this wavelength was measured to quantify the soil component (the liquid paraffin) in the cleaning waste liquid.

As the cleaning waste liquid, 99 parts by weight of water, 1 part by weight of Softanol 90 as a nonionic surfactant (manufactured by Nippon Shokubai Co., Ltd., cloud point 56 ± 5 ° C.), and 0.1036 parts by weight of the above-mentioned stain component. What was stirred and dissolved was used.
FIG. 1 shows the purification device. Put 1 liter of cleaning waste liquid into a 2 liter beaker 10 and stir at room temperature with a flow rate of 40 ml per minute and a heater 20 of 150 W.
While passing through the adsorption tank 30 equipped with (Saiden Electric Co., Ltd. silicon blade 5 m) while heating, a cooling tank 40
After that, the operation of returning to the beaker 10 was performed for 1 hour. The device was operated by pump 50. In addition,
The following porous body 31 was placed in the adsorption tank 30. The temperature at the outlet of the adsorption tank 30 was 65 ± 5 ° C. Only in Example 1, as shown in FIG. 2, a separation tank 60 was provided between the adsorption tank 30 and the cooling tank 40. A heater 20 similar to the adsorption tank 30 was attached to the separation tank 60. Absorbance of visible light of 420nm of cleaning waste liquid before and after purification is measured by spectrophotometer UV-31.
00 (manufactured by Shimadzu Corp.), and quantify the stain component from the calibration curve obtained in advance, and obtain the amount after purification when the amount of stain component before purification is 1, and The results are shown in Table 1.

[0017]

[Table 1] ──────────────────────────────────── Porous body used in the adsorption tank After washing Amount of dirt components of ──────────────────────────────────── Example 1 ─ 1/80 Example 2 Kimwipe (manufactured by Tojo Kimberley Co., Ltd.) 1/150 Example 3 Filter paper (No. 2 filter paper manufactured by Toyo Roshi Kaisha, Ltd.) 1/125 Example 4 Cotton 1/100 ───────────── ─────────────────────────

[0018]

EFFECTS OF THE INVENTION According to the method for removing dirt components from a cleaning waste liquid according to the present invention, a nonionic surfactant, which has been difficult to remove in the present sewage treatment facility using activated sludge, is removed from the waste liquid together with the dirt components. Since it is separated and removed, it leads to lower COD of wastewater. The cleaning waste liquid after separation and removal of the dirt component can be used again for cleaning. In this case, since the ionic surfactant has not been removed, it can be reused and is economical.

[Brief description of drawings]

FIG. 1 is an explanatory view of a purifying device used in an embodiment of the present invention.
(a) and explanatory drawing (b) inside the adsorption tank.

FIG. 2 is an explanatory diagram of a purifying device used in Example 1.

[Explanation of symbols]

 10 Beaker 20 Heater 30 Adsorption tank 31 Porous body 40 Cooling tank 50 Pump 60 Separation tank

Claims (3)

[Claims] 1. A washing waste liquid produced by washing with a detergent composition in which the surfactant portion comprises a nonionic surfactant alone or a mixture of a nonionic surfactant and an ionic surfactant. A method for removing a stain component from a cleaning waste liquid, wherein the stain component is separated and removed from the cleaning waste liquid together with the nonionic surfactant by heating above the cloud point of the nonionic surfactant. 2. The method for removing contaminants from a cleaning waste liquid according to claim 1, wherein a porous material is allowed to coexist in the cleaning waste liquid when the cleaning waste liquid is heated to a temperature above the cloud point of the nonionic surfactant. . 3. The method for removing dirt components from a cleaning waste liquid according to claim 1 or 2, wherein the porous body is composed of a polysaccharide fibrous substance.