JP2008173610A - Waste liquid treating method and waste liquid treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste liquid treating method and a waste liquid treatment system with simplified drain treatment after treating water-soluble cutting oil. <P>SOLUTION: The waste liquid treatment system treating waste liquid consisting of water-soluble cutting oil 11 is provided with a pH controlling tank 13 turning pH of the water-soluble cutting oil 11, the waste liquid, to the alkaline side by adding an alkali agent 12, a coagulation tank 15 for adding a coagulant 14 after pH controlling for blending, a coagulation tank 17 coagulating by adding a polymer coagulant 16, and a dewatering machine 18 dewatering aggregate to form dewatered cake 19. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a waste liquid treatment method and a waste liquid treatment system capable of efficiently treating water-soluble cutting oil used in other cutting machines and the like.

  For example, various cutting machines such as lathes, milling machines, drilling machines, and sawing machines use a large amount of water-soluble cutting oil in order to increase their cutting performance. Since the functions such as rust prevention and antiseptic properties are reduced, the water-soluble cutting oil having the reduced functions is treated with a waste liquid after a predetermined time.

  Here, as conventional waste liquid treatment methods for water-soluble cutting oil, conventional physical treatment methods such as sedimentation separation, flotation separation, filtration separation, and centrifugal separation, for example, agglomeration method, oxidation and reduction method, adsorption method, etc. Chemical treatments such as ion exchange methods, biological treatment methods such as activated sludge methods and sprinkling filter beds, incineration treatment methods, and the like are known.

  However, water-soluble cutting oil is an emulsion or soluble produced by adding an emulsifier, and a large amount of metal microparticles are mixed in the waste, so that complete separation is difficult in physical processing. However, incineration treatment requires a lot of energy and it is difficult to burn completely, and in chemical treatment, it is difficult for the separated water after treatment to meet the drainage standard by the Water Pollution Control Law. (See Patent Documents 1 to 3).

  For this reason, it is proposed to acid-treat water-soluble cutting oil, for example in pH 3 or less, or pH 3-7 (refer patent documents 4 and 5).

Japanese Patent Laid-Open No. 06-154508 Japanese Patent Application Laid-Open No. 06-192023 JP 2000-73084 A JP 2004-105915 A JP 2005-46657 A

  However, in the case of acidic wastewater treatment, there is a problem that pH adjustment (dilution treatment or alkali treatment) of the wastewater after treatment is required.

  This invention makes it a subject to provide the waste liquid processing method and waste liquid processing system which simplified the waste water treatment after the process of water-soluble cutting oil in view of the said problem.

  The first invention of the present invention for solving the above-mentioned problem is a waste liquid treatment method for treating a waste liquid comprising a water-soluble cutting oil, wherein the pH of the waste liquid is set to the alkali side, and then a flocculant is added, A waste liquid treatment method is characterized in that a dehydration process is performed with a dehydrator.

  A second invention is the waste liquid treatment method according to the first invention, wherein the pH of the waste liquid is adjusted to pH 9.5 or more.

  A third invention is a waste liquid treatment system for treating a waste liquid composed of water-soluble cutting oil, a pH adjustment tank in which the pH of the waste liquid is an alkali side, a coagulation tank in which a flocculant is added and mixed after pH adjustment, A waste liquid treatment system comprising a dehydrator for dewatering aggregates.

  A fourth invention is the waste liquid treatment system according to the third invention, wherein the pH in the pH adjusting tank is 9.5 or more.

  According to a fifth invention, in the third or fourth invention, the coagulation tank includes a first coagulation tank obtained by adding an inorganic coagulant and a second coagulation tank obtained by adding a polymer coagulant. It is in the waste liquid processing system characterized by becoming.

  A sixth invention is characterized in that, in any one of the third to fifth inventions, the second aggregating tank further comprises either one or both of an anionic and cationic polymer flocculant. In the waste liquid treatment system.

  A seventh invention is the waste liquid treatment system according to any one of the third to sixth inventions, wherein the dehydrator is a multi-disk dehydrator.

  According to the present invention, water-soluble cutting oil can be easily treated, and the moisture content of the dehydrated cake of aggregates can be reduced.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment or an Example. In addition, constituent elements in the following embodiments or examples include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment of the Invention]
FIG. 1 is a schematic diagram of a first waste liquid treatment system according to the present embodiment.
As shown in FIG. 1, the first waste liquid treatment system 10 </ b> A is a waste liquid treatment system for treating a waste liquid composed of a water-soluble cutting oil 11, and the pH of the water-soluble cutting oil 11 as a waste liquid is increased by adding an alkali agent 12. A pH adjusting tank 13 on the side, an aggregating and mixing tank 15 to which the flocculant 14 is added and mixed after the pH adjustment, an aggregating tank 17 to which the polymer flocculant 16 is added and aggregated, and the aggregates are dehydrated. A dehydrator 18 serving as a dehydrated cake 19 is provided. According to the waste liquid treatment system of the present embodiment, the water content of the agglomerated dewatered cake 19 can be lowered and the water-soluble cutting oil treatment facility is simple as shown in the examples described later. Can be provided. This is because the addition of the alkaline agent 12 causes the emulsified waste liquid to undergo emulsion break (saponification) and is processed so as to easily aggregate.

  Here, the water-soluble cutting oil 11 which is a waste liquid is a water-soluble cutting oil waste liquid used to improve the cutting performance in various cutting machines such as a lathe, a milling machine, a drilling machine, and a sawing machine.

  For example, sodium hydroxide can be used as the alkaline agent 12 added to the pH adjusting tank 13 for alkali treatment of the water-soluble cutting oil 11, and the pH thereof is 9.5 or more, preferably 9.5 to 11. 0.5, and more preferably in the range of pH 10.5-11.

  This is because if the pH is less than 9.5, the dehydration cake 19 having a predetermined moisture content or less cannot be obtained without agglomeration in the agglomeration tank.

  As the flocculant 14 used in the flocculent mixing tank 15, an inorganic flocculant is preferably used. Here, as the inorganic flocculant, there are an iron flocculant and an aluminum flocculant. Either of them may be used, but an aluminum flocculant is particularly preferably used.

  This is because the iron-based flocculant has a good sedimentation property but has a problem in measures against corrosion of the apparatus. Moreover, it is because it is preferable to reduce the chloride ion content in the dewatered cake 19 when the dewatered cake 19 dehydrated by the dehydrator 18 is used as, for example, a concrete material.

  Examples of the aluminum flocculant include polyaluminum chloride (PAC), aluminum sulfate (sulfuric acid band), and aluminum chloride. Examples of the iron flocculant include ferrous chloride and ferric chloride. Examples thereof include iron, ferrous sulfate, ferric sulfate, polyiron sulfate, and polyferric sulfate. Moreover, you may make it use these inorganic type flocculants suitably selecting 1 type (s) or 2 or more types as needed.

  Further, when aluminum sulfate is used as the aluminum-based flocculant, the pH of the treated water (neutral treatment) can be adjusted, and it is particularly preferable because it is not necessary to separately adjust the pH of the waste liquid of the dehydrated cake and perform the waste liquid treatment. .

  The polymer flocculant 16 uses one or both of an anionic (anionic) flocculant and a cationic (cationic) flocculant.

  When the anionic flocculant and the cationic flocculant are used in combination, as shown in the second waste liquid treatment system 10B in FIG. 2, the flocculant tank 17 to which the polymer flocculant 16 shown in FIG. 1 is added. May be a first flocculating tank 17A to which the first polymer flocculant 16A is added and a second flocculating tank 17B to which the second polymer flocculant 16B is added.

  The two types of polymer flocculants are sequentially added to the separate first flocculant tank 17A and second flocculant tank 17B, respectively, but when the anionic flocculant is added and then the cationic flocculant is added. Whether the anionic flocculant is added after the cationic flocculant is added or not may be set as appropriate depending on the properties of the cutting oil drainage to be treated.

  Here, examples of the polymer flocculant include, for example, polyacrylic acid soda (anionic), polydimethylaminoethyl acrylate (cationic), polyacrylamide partial hydrolyzate (anionic), and polyacrylamide. Sulfonation derivative (anionic), polystellensulfonic acid soda (anionic), polyvinyl benzyl trimethyl ammonium chloride (cationic), polyvinyl pyridine salt (cationic), maleic acid polymer ( Anionic), polyamine (cationic), polyamine polyamide (cationic), polythiourea (cationic), polyethyleneimine (cationic), poly (dimethylaminoethyl acrylate) (cationic), etc. However, the present invention is not limited to these.

Here, as an example of the processing amount of the waste liquid treatment system of the present embodiment, 10 L of sodium hydroxide (10% solution) and aluminum sulfate (8%) with respect to 1 m ³ of the stock solution of the water-soluble cutting oil 11 16 L ± 2 L, anionic polymer flocculant (0.2% solution, for example, “Diafloc AP-120C” (trade name) manufactured by Dianitics) 53 L ± 5 L, cationic polymer flocculant (0.4 % Solution, for example, “Diafloc KP-201G” (trade name) (manufactured by Daianitrix Co., Ltd.) is added to each of 82 ± 8 L.

  According to the present invention, the water content of the dehydrated cake 19 after the dehydration treatment is about 80% or less, and the subsequent handling becomes good.

  As the dehydrator 18, a commercially available dehydrator can be used in the present invention. For example, a multi-disk dehydrator is particularly preferable because a moisture removal rate can be efficiently performed.

As a result, the amount of industrial waste of the dewatered cake 19 can be greatly reduced. For example, if treated with 1 m ^{3 of the} stock solution, about 30 L of dehydrated cake 19 can be obtained.

  Further, the dehydrated cake 19 can be used as, for example, a mixed material of concrete, the dehydrated cake 19 can be reused, and unnecessary industrial waste disposal can be reduced.

  Furthermore, since the dehydrated cake 19 is mostly made of oil (and water), combustion treatment is also possible.

  In this way, the system of the present invention uses simple pH adjustment and agglomeration / dehydration equipment, which also simplifies the number of system equipment, enables easy operation and efficient processing of the system, It is particularly preferred for use in water-soluble cutting oil treatment.

Examples illustrating the effects of the present invention will be described.
In this embodiment, the second waste liquid treatment system 10B shown in FIG. 2 was used.
Here, the cutting oil waste liquid sludge used in the automobile production line was used as the treatment liquid of this example.
20 L of 10% sodium hydroxide was added to 2 m ^{3 of} this cutting oil waste liquid sludge, and the pH was adjusted to 9.5 in the pH adjusting tank 13.
Next, 32 L of aluminum sulfate (Al ₂ O ₃ 8%) was added as the inorganic coagulant 14 and coagulated and mixed in the coagulation mixing tank 15.
Thereafter, an anionic polymer flocculant (0.2% solution, for example, “Diafloc AP-120C” (trade name): manufactured by Daianitrix Co., Ltd.) is added as the first polymer flocculant 16A. Cationic polymer flocculant (0.4% solution, for example, “Diafloc KP-201G” (trade name): manufactured by Dianitics) was added as the molecular flocculant 16B.

  As a result of these, the treatment amount and SS concentration of sludge, the addition rate of the polymer flocculant, and the moisture and DS amount of the dewatered cake are shown in “Table 1” below.

  As shown in Table 1, when the sludge pH treatment was 9.5, the agglomeration treatment proceeded efficiently, and a dehydrated cake having a cake moisture (water content) of 80% or less could be obtained. However, when the pH was 9.0, the agglomeration treatment was poor and the dehydration treatment was impossible.

  As described above, according to the wastewater treatment system and method for water-soluble cutting oil according to the present invention, the moisture content of the dewatered cake of agglomerates can be reduced, and simple treatment for treating deteriorated water-soluble cutting oil. A system can be provided.

It is the schematic of the 1st waste liquid processing system which concerns on this Embodiment. It is the schematic of the 2nd waste liquid processing system which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10A 1st waste liquid processing system 10B 2nd waste liquid processing system 11 Water-soluble cutting oil 12 Alkaline agent 13 pH adjustment tank 14 Coagulant 15 Coagulation mixing tank 16 Polymer coagulant 16A 1st polymer coagulant 16B 2nd Polymer flocculant 17 Coagulation tank 17A First coagulation tank 17B Second coagulation tank 18 Dehydrator 19 Dehydrated cake

Claims (7)

In the waste liquid treatment method for treating waste liquid consisting of water-soluble cutting oil,
A waste liquid treatment method, wherein the pH of the waste liquid is set to the alkali side, a flocculant is added thereafter, and the agglomerate is dehydrated by a dehydrator. In claim 1,
A waste liquid treatment method comprising adjusting the pH of a waste liquid to pH 9.5 or more. In a waste liquid treatment system for treating waste liquid consisting of water-soluble cutting oil,
A pH adjustment tank in which the pH of the waste liquid is alkali,
a flocculant tank in which a flocculant is added and mixed after pH adjustment;
A waste liquid treatment system comprising a dehydrator for dewatering aggregates. In claim 3,
The waste liquid treatment system, wherein the pH in the pH adjustment tank is 9.5 or more. In claim 3 or 4,
The waste liquid treatment system, wherein the flocculation tank comprises a first flocculation tank to which an inorganic flocculant is added and a second flocculation tank to which a polymer flocculant is added. In any one of Claims 3 thru | or 5,
The waste liquid treatment system, wherein the second flocculation tank further comprises one or both of an anionic and cationic polymer flocculant. In any one of Claims 3 thru | or 6,
A waste liquid treatment system, wherein the dehydrator is a multiple disk dehydrator.

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