JPS6050481B2 - Wastewater treatment method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for treating wastewater containing emulsified oil.

Industrial wastewater containing oil causes pollution such as river pollution and ocean pollution, which has become a major social problem. Among these wastewaters, when the oil content is in an emulsified state due to the coexistence of surfactants, etc., or when the oil particle size is extremely fine, treatment of so-called emulsified oil is performed using dispersed oil with relatively large particle size. The oil/water separation process is extremely difficult compared to the conventional method. These wastewaters are discharged from factories in many industries, including the machinery industry, chemical industry, petroleum industry, and steel industry, as well as the food industry, painting industry, and textile industry. Conventionally, methods for treating wastewater containing emulsified oil include, for example, electrolysis, addition of salting-out agents, flocculants, adsorbents, etc., and separation of oil and water by pressure flotation, coagulation sedimentation, or filtration. Method,
Methods include dissolving and extracting oil with a solvent, but any of the following 9■ &f■: L゛↓, ^ j-, nE
, J4 Mountain ＾＾ﾂ゛□ In order to reduce the level below the moaner eruption limit, large-scale equipment or long-term processing may be required, and depending on the method, the current emissions in Japan may be reduced. Since it is difficult to reduce the oil concentration to 30 pμm or less for animal and vegetable oils (standard mineral oil: 5 pμm), it has drawbacks such as requiring some kind of secondary treatment.

Furthermore, a method has been proposed in which, for example, an amine derivative that is liquid at room temperature or modified to have an affinity for water is used as an emulsion breaking agent. This is a method that can be effective. This method not only requires a stirring device but also makes it difficult to separate the added emulsion breaker, making it difficult to reduce the COD of the liquid to be treated below the regulatory value. In view of the current situation, the inventors of the present invention have conducted intensive studies on an emulsified oil treatment method that can easily separate the treatment material from the water to be treated and that is easy to operate. The present invention was achieved by discovering that it has an effect on adsorption.

That is, the present invention is a method for treating wastewater, which is characterized in that when treating emulsified oil-containing wastewater, the wastewater is brought into contact with an amine compound and/or a derivative thereof having 6 to 60 carbon atoms.

The amine compounds having a hydrocarbon chain having 6 to 60 carbon atoms used in the method of the present invention include primary amines, secondary amines, tertiary amines and derivatives thereof, and more preferably primary amines and secondary amines. and derivatives thereof, particularly preferred are primary amines (eg stearlyamine) and derivatives thereof.

These amine compounds include, for example, primary amines such as hexylamine, heptylamine, octylamine, nonylamine, decylamine, laurylamine, myristylamine, palmitylamine, oleylamine, and stearylamine, or diamines having a hydrocarbon chain thereof; Secondary amines such as triamines, tertiary amines or their viclates, various salts (e.g. hydrochloric acid, sulfuric acid, phosphoric acid,
salts of carbonic acid, acetic acid, etc.), acid amides and amidines of primary amines and secondary amines having these hydrocarbon chains,
These include ureas and thioureas, and Schiff bases of primary amines. Note that N-stearylacetamide is preferred as the amide. In addition, polyvalent amines such as stearylpropylene diamine and semi-hardened tallow diamine can also be used. Furthermore, it is also possible to use a mixture of amines having hydrocarbon chains having different numbers of carbon atoms, such as hardened tallow amine and coconut amine. Note that even if one component of the amine compound is non-solid at room temperature, it can be preferably used as long as the mixture with other amine compounds is solid. It is necessary that the amine compound and/or its derivative used in the method of the present invention be insoluble in water.

This is because this treated material removes emulsified oil that becomes emulsified in water, so it dissolves in water during treatment. This is because it is desirable that the active ingredients necessary for the removal treatment not be lost due to leakage. The amine compound and/or its derivative used in the present invention has a structure having a hydrophobic hydrocarbon chain and a hydrophilic group in the molecule. The emulsion particles have a favorable balance with the emulsion particles, and the emulsion particles are adsorbed with affinity, and the adsorbed emulsion particles eventually coalesce to coarsen the particles, causing an emulsion destruction phenomenon. it is conceivable that.

In this case, the Hl. A relatively low B number works effectively, so in general, amine compounds with less than 6 carbon atoms have a small proportion of hydrophobic moieties, and have suitable hydrophobic and hydrophilic properties for emulsion particles. Since no balance is obtained, the effect of adsorption and destruction of emulsion particles is considered to be small. On the other hand, the number of carbon dioxide is 6
If it exceeds 0, the ratio of the hydrophobic portion is too high, and it is considered that suitable affinity cannot be imparted to the emulsion particles. The emulsified oil targeted by the method of the present invention is a chemical compound that has the property of being emulsifiable in a liquid medium (mainly water), and emulsified oil (for example, animal or vegetable oil, mineral oil). Usually shown.

However, even if it is a free oil or one that is not commonly referred to as an oil, if it can be emulsified under certain conditions, it is included in the emulsified oil that is the object of the present invention. The processing material of the present invention mainly has the ability to coarsen fine oil droplets and destroy emulsions.

Therefore, even if oil is adsorbed and the saturation point is reached, the emulsion breaking ability persists, and the aqueous solution treated with this treated material may become emulsified; It is possible to completely separate the emulsion by treating it with a conventionally existing oil adsorbent for free oil adsorption that has only hydrophobicity. Therefore, the treatment material of the present invention can effectively treat emulsifying compounds even when used in combination with an oil adsorbent for free oil treatment. The method of separating emulsified oil of the present invention can basically be carried out by efficiently bringing the amine compounds into contact with water containing emulsified oil, especially waste water.

Therefore, any method may be used as long as the amine compounds and the emulsified oil wastewater can be brought into contact with each other efficiently, but generally a method of passing the emulsified oil wastewater through the amine compound is used. For example, a column is filled with granules, pieces, or powder of the amine compound (the amine compound may be kneaded with a clay material, etc., if necessary), and emulsified oil-containing wastewater is passed through using a pump or the like. This is a method of making liquid. It is also possible to treat emulsified oil by adding the compounds into a storage tank of emulsified oil-containing wastewater, mixing and stirring, and then filtering. In this case, since the emulsion of the emulsified oil is broken and adsorbed by the compound, the water to be treated and the oils can be separated by simple filtration without forming so-called flocs. The treatment method of the present invention is effective in treating wastewater containing emulsified oils such as mineral oils, animal and vegetable oils, and the like.

For example, compressor drain, wastewater containing water-soluble cutting oil containing a surfactant, wastewater from washing rolled steel plates, wastewater from car washing, or emulsified oil made of animal and vegetable oils discharged from the food industry can be efficiently treated. The treatment method of the present invention can treat various emulsified oil-containing wastewaters in a very simple manner.

The separation effect of emulsified oil is that it may be possible to separate oil and water to an extent that cannot be detected by measuring the oil concentration using the n-hexane extraction method in emulsified oil that consists of fine oil droplets with a particle size of 10μ or less, and is below the emission standard. It becomes possible to reduce the oil concentration to a concentration of . The present invention*3 is a method for treating emulsified oil wastewater that has great industrial value. The present invention will be explained below with reference to Examples.

All "Ppm" representing concentrations in the examples are based on weight. Note that the oil concentration in Examples was measured by the n-hexane extraction method based on JISK-0102.

Example 1 Stearylamine powder was added to emulsified oil-containing wastewater containing water-soluble cutting oil Cutwell 40 (manufactured by Etsuo Oil Co., Ltd.), stirred with a magnetic stirrer, and then filtered to obtain colorless and transparent treated water. .

The oil concentration in the treated water was measured and the results are summarized in Table 1. Example 2-3 Water-soluble cutting oil Cutwell 40 (manufactured by Etsuo Oil) 50
Powder of a primary amine having a long-chain aliphatic hydrocarbon group was added to wastewater containing emulsified oil containing ppm and stirred with a magnetic stirrer. The oil concentration in the offshore liquid was measured and the results are shown in Table 2.

Example 4-6 Water-soluble cutting oil Cutwell 40 (manufactured by Etsuo Oil) 50
Powder of a secondary amine or diamine having a long-chain aliphatic hydrocarbon group is added to emulsified oil-containing wastewater containing ppm, stirred with a magnetic stirrer, filtered, and the oil concentration in the filtrate is measured and the results are shown in the table. Shown in 3.

Example 7 A glass column with a diameter of 147 Trm was filled with 5.0y of stearylamine powder of 300 mesh, and emulsified oil wastewater containing 100 ppm of water-soluble cutting oil Cutwell 40 (manufactured by Etsuo Oil) was passed through it at a flow rate of 5 ml/min. However, when the oil concentration in the treated water flowing out from the column was measured, the oil concentration was 1.0 ppm.

Claims (1)

[Claims] 1 When treating wastewater containing emulsified oil, carbon number 6-60
A method for treating emulsified oil-containing wastewater, which comprises bringing the wastewater into contact with a water-insoluble amine compound and/or its derivative having the following.