KR19990001036A - Apparatus and method for treating oil and heavy metals in wastewater - Google Patents

Abstract

The present invention relates to an apparatus and method for purifying wastewater or waste oil containing oil and heavy metals such as cutting oil or lubricating oil, and more specifically, oil and heavy metals contained in waste water or waste oil using an electrolysis method. The present invention relates to an apparatus and method for treating oil and heavy metals in wastewater which can reduce wastewater treatment costs by effectively removing the wastewater and significantly reduce the emission of environmentally damaging materials.

The method of treating oil and heavy metals in the wastewater of the present invention comprises agitation of the oil by an electron and a magnetic field by stirring the wastewater containing oil and heavy metal having a high charge and passing the electrode; Floc formation by adding flocculant to increase the size of the flocculant; Oxygen and hydrogen gas are adsorbed on the surface of the floc and float; Adding flocculant to the flocs and separating the flocs and water; And draining water and reducing the volume of the flocs. In addition, the oil and heavy metal treatment apparatus in the wastewater of the present invention, the collection tank (1) provided with a stirring means which is operated by the motor (8) to uniformly stir the wastewater or waste oil flowing in the state containing the oil or heavy metal; A flow meter (3) for measuring the amount of waste water or waste oil discharged from the collection tank (1); A decomposition tank (4) for agglomeration of the oil in the wastewater flowing out of the collection tank (1) and discharging it in a floc state, the plurality of electrodes (43) having a positive electrode and a negative electrode respectively connected thereto; Stirring tank (5) for agitating the waste water separated from the water and floc while flowing out of the decomposition tank (4); And a settling tank 6 including a guide plate 61 which separates the water and the floc discharged from the stirring tank 5 to discharge the water to the drain passage 62 and discharge the floc to the upper side.

Description

Apparatus and method for treating oil and heavy metals in wastewater

The present invention relates to an apparatus and method for purifying wastewater or waste oil containing oil and heavy metals such as cutting oil or lubricating oil, and more specifically, oil and heavy metals contained in waste water or waste oil using an electrolysis method. The present invention relates to an apparatus and method for treating oil and heavy metals in wastewater which can reduce wastewater treatment costs by effectively removing the wastewater and significantly reduce the emission of environmentally damaging materials.

In the cutting process using the lathe in the factory, cutting oil containing moisture is used to smoothly maintain the rotation of the motor rotating at high speed and to cool it by the high speed rotation. The use of such coolant is inevitable because no other alternatives exist, but large-scale wastewater causes environmental pollution, which is a costly and time-consuming process for treating wastewater containing oil. Wastewater containing oil is a hardly decomposable substance due to its characteristics. Currently, industrial wastewater, oil and waste oil are incinerated or separated from water and oil using a centrifugal separator.

However, since incineration is performed without separating water and oil components, it is not well incinerated by water, which accounts for more than 95% of wastewater and waste oil, and surfactants (extreme pressure additives, Emulsifier) is added, so the problem of toxic substances emitted during incineration was exposed. In addition, even in the case of using a centrifugal separator, one hundred small tons of wastewater or waste oil is generated annually in one small- and medium-sized plant, which consumes a lot of cost and time for processing, and consequently, it is a cost burden to SMEs.

Due to such a problem, it has conventionally been illegally discharged into a river at night or in rainy weather or illegally buried. This problem was essentially the same problem not only in the wastewater generated in the factory but also in the wastewater generated in the process of washing the car at the car wash.

The present invention has been made to solve the above problems, an object of the present invention is to separate the water from the waste water or waste oil containing oil and to treat the oil in the waste water and the treatment cost is reduced and the risk of environmental pollution and It is to provide a heavy metal processing apparatus and method.

Another object of the present invention is to provide an apparatus and a method for treating oil and heavy metals in wastewater which can be treated by reducing the fraction of wastewater or waste oil by separating the water contained in the waste water or waste oil using electrolysis.

Oil and heavy metal treatment method in the wastewater of the present invention for achieving the above object, agitated by the electron and magnetic field by stirring the wastewater containing oil and heavy metal having a high charge and passing through the electrode; Floc formation by adding flocculant to increase the size of the flocculant; Oxygen and hydrogen gas are adsorbed on the surface of the floc and float; Adding flocculant to the flocs and separating the flocs and water; And draining water and reducing the volume of the flocs. In addition, the oil and heavy metal treatment apparatus in the wastewater of the present invention, the collection tank is provided with a means for uniformly stirring the wastewater flowing in the state containing the oil or heavy metal; A decomposition tank for neutralizing and discharging colloid in the wastewater flowing out of the collection tank; A stirring tank for agitating wastewater separated from the floc while being discharged from the decomposition tank; And a settling tank for separating the floc and the water flowing out of the stirring tank.

1 is a block diagram of one embodiment of a processing apparatus in which the method of the present invention is performed;

FIG. 2 is a side sectional view showing the structure of the decomposition tank of FIG. 1; FIG.

3 is a side view for explaining the state of the floc in the decomposition tank;

4 is a flow chart illustrating the method of the invention.

* Description of the symbols for the main parts of the drawings *

1: collection tank, 2: conduit,

3: flow meter, 4: digester,

5: stirring tank, 6: precipitation tank,

7: activated carbon, 8,9,10: motor,

41: outer tide, 42: inner tide,

43: electrode, 44: motor,

45: wing, 46: surface,

47: burner, 48: pump,

49: polymer coagulation bath, 61: guide plate,

62: drainage passage.

Hereinafter, an apparatus and a method for treating oil and heavy metals in wastewater of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, water and oil are separated by a complex action such as oxidation, reduction, decomposition, gas generation, flocculation, and adsorption by electrolysis while passing waste water or waste oil containing oil through a decomposition tank, and the separated oil is separated. It has a feature that can be easily removed by flotation and floating. In order to promote the formation of flocs, flocculants or polymer flocculants may be added in a digestion tank or elsewhere. When the separated flocs are solidified and compressed, they have a volume of 1/15 to 20 in a state of containing water, and thus are easily incinerated and have excellent oil removal effects such as treatment by centrifugation. In addition, the heavy metals were formed by electrolysis of H ⁺ and OH ^- Cu (OH) ₂ , Zn (OH) ₂ , Pb (OH) ₂ , Fe (OH) ₂ , Cd (OH) ₂ , and Ni (OH). ) ₂ , Mg (OH) ₂ , Al (OH) ₂ , Mn (OH) ₂ , Cr (OH) ₂ , Sn (OH) ₂ , and Co (OH) ₂ can be combined to remove heavy metals. .

The method of the present invention comprises the following steps: agitating the oil by electrons and magnetic fields by stirring the wastewater containing oil and heavy metal with high charge and passing the electrode; Floc formation by adding flocculant to increase the size of the flocculant; Oxygen and hydrogen gas are adsorbed on the surface of the floc and float; Adding flocculant to the flocs and separating the flocs and water; And draining the water and reducing the volume of the floc, which is described in the flowchart of FIG.

First, the configuration and operation of the treatment apparatus of the present invention will be described with reference to FIG.

As shown, the collection tank (1) provided with means operated by the motor (8) to uniformly stir the wastewater or the waste oil flowing into the state containing the oil or heavy metal; A flow meter (3) for measuring the amount of waste water or waste oil discharged from the collection tank (1); A decomposition tank 4 for discharging the colloidal components in the wastewater flowing out from the collection tank 1 in a neutralized state, and having a plurality of electrodes connected to the anode and the cathode, respectively; Stirring tank (5) for agitating the waste water separated from the water and floc while flowing out of the decomposition tank (4); And a settling tank 6 including a guide plate 61 for separating the water and the floc discharged from the stirring tank 5 to discharge the water to the drain passage 62 and to discharge the floc to the upper side.

At the top of the treatment apparatus is a collection tank 1 for collecting waste water or waste oil containing oil. The collection tank 1 may be a cylindrical or square tank having a certain size, which depends on the amount of waste water or waste oil that can be treated. In addition, it will be apparent to those skilled in the art to which the present invention pertains that other large collection tanks may be installed in front of the collection tank 1 in order to keep the inflow of waste water constant.

The waste water or waste oil collected in the collection tank 1 may be moved through a pipe extending directly from the factory or may be moved after being collected by a separate waste water or waste oil collection truck. The collected waste water or waste oil enters the digestion tank 4 through the conduit 2.

In the conduit 2 between the collection tank 1 and the decomposition tank 4, a flow meter 3 capable of measuring the flow rate is installed so that waste water or waste oil in a proper state can be introduced into the decomposition tank 4. do. The inflow of wastewater is changed according to the capacity of the decomposition tank 4.

Waste water or waste oil introduced into the decomposition tank 4 is neutralized for coagulation. This neutralization is performed while the wastewater passes through the electrodes of the anode and cathode installed in the decomposition tank 4. In order to promote the electrolysis, the positive electrode is preferably made of stainless steel and the negative electrode is made of stainless steel or steel. Or it is also possible to neutralize using the neutralizing agent in the said collection tank 1 previously.

Oil-in-water (colloidal) substances in water have a positive intrinsic charge, either positive or negative. These oil particles with a constant charge are to promote the aggregation of the oil particles by neutralization because they interfere with the coagulation by the electrostatic repulsion and H + or OH-generated in dissociation. As the particles in the electrolytic state pass between the electrodes, the oily substances are neutralized by the electric disturbance effect. Alternatively, the waste water or waste oil stored in the collection tank 1 is usually acidic or alkaline, so neutralizing agents such as Alumium, (Al ₂ (SO ₄ ) _{3 18} H ₂ O), NaCl, NaOH, CaCO _3, etc. It can be neutralized by putting into the collection tank (1). This neutralization has the effect of promoting the reaction. In addition, the agitation means operated by the motor 8 is installed inside the collection tank 1 to uniformly mix the neutralized wastewater. The rotation speed of the motor 8 at this time may be about 300 RPM.

As described above, the neutralized oil material is introduced to the surface of the water by the oxygen and hydrogen gas generated by the magnetic field generated by the electrolysis between the electrodes. The oxygen and hydrogen gas is partially dissolved in water, but most of the bubbles are attached to the oil as a bubble state, thereby acting to raise the oil to the surface. This is described later with reference to FIG. 3. The wastewater treated in the cracking tank 4 is forcibly moved to the stirring tank 5 by the pump 48 through the conduit 2 formed at the bottom.

2 is a cross-sectional view showing the structure of a decomposition tank 4 in which electrolysis is generated as described above. As shown, a plurality of electrodes 43 are arranged on the upper side of the decomposition tank 4 spaced apart from the predetermined interval (D). Each of the electrodes 43 is staggered, so that the movement of the wastewater is configured smoothly, and the adjacent electrodes 43 are connected to a power source so as to have different polarities. The distance D between the electrodes 43 is preferably configured to be about 3 cm so as to apply direct heat generated by the magnetic field between the electrodes, for example. In addition, stirring means are further provided to promote the reaction. The electrode 34 is supplied after modulating alternating current into direct current using a rectifier.

The _{H 2 O + 1/2 O 2 +} 2e - - that are produced, in the cathode 2H ^{+ +} 2e ^- H ₂ occurs by the positive electrode by electrochemical reaction at 20H when the power is supplied to the waste water electrode 43 do. The oxygen and hydrogen gas thus generated are adsorbed to neutralized oil (colloid) to produce flocs. The oil with oxygen and hydrogen gas adsorbed rises above the surface because its specific gravity is lighter than water. The floating speed at this time is about 1.5 to 4 cm / sec, depending on the size of the oil. At this time, in the whole country, direct heat is generated under the influence of electrons and magnetic fields, and the reaction rate is increased, and oxidation, reduction, decomposition, gas generation, aggregation, and adsorption are combined by electrolysis.

In the center of the decomposition tank 4, a motor 44 and a blade 45 are provided as stirring means for stirring wastewater. The rotation speed of the blade 45 is preferably operated at 100 RPM or less.

In addition, in the decomposition tank 4, the outer tank 41 and the inner tank 42 have a double structure so that heat can be applied from the outside to promote electrolysis, and a space S is formed therebetween. Since the space (S) has a steam inlet (a) and steam outlet (b) to move the steam supplied from the boiler separately installed in the direction of the arrow to increase the temperature of the inner tank 42 by injecting and circulating the steam. Can be.

The same effect can be obtained by installing and heating the burner 47 at the lower part of the outer tub 41 instead of steam. It is also desirable to coat the surface 46 of the inner tub 42 with an insulating material, such as rubber coating, urethane coating, or ceramic coating, in order to minimize the influence from the outside during the reaction.

Figure 3 shows that the oxygen and hydrogen gas generated by the electrolysis rises around the oil. It can be seen that oxygen and hydrogen aggregate and rise outside the neutralized fraction. It is also possible to separate the decomposition tank 4 into primary and secondary tanks in order to enhance the electrolytic action and increase the oil treatment effect. That is, by connecting the decomposition tank 4 as shown in Figure 2 in series it is possible to further increase the processing efficiency.

The floated floc flows into the stirring vessel 5 through a conduit 2 formed between the digestion vessel 4 and the stirring vessel 5. The stirring vessel 5 is for mixing the floss uniformly, and initially rotates at a relatively high speed (300 RPM) and then stirs again at a low speed of 120 RPM.

At this time, in order to further increase the size of the floc, the polymer coagulant may be introduced into the stirring tank 5 using the polymer agglomeration tank 49. The larger flocculated floc then rises to the surface and moves through conduit 2 to the settling tank 6. At this time, the water moves together and the water and the flocs are separated in the settling tank (6). That is, the water is discharged to the outside through the drain passage 62 formed in the lower portion of the settling tank 6 and the floc is discharged to the outside through the guide plate 61 formed on the top. The floc state at this time is a state containing water, but it can be seen that the water is significantly reduced compared to the conventional one because the oil and water are separated and extracted respectively. The floc discharged through the upper conduit 2 of the settling tank 6 may be collected in its state and incinerated or completely removed while passing through the activated carbon tank 7.

Table 1 below shows the treatment result of the cutting oil as an oil component, and compares the amount of oil in the wastewater generated in the machining process with the amount of oil present in the wastewater after the treatment.

TABLE 1

NO Pretreatment (mg / l) After treatment (mg / l) Processing efficiency (%) One 55000 3 99.99 2 55000 3 99.99 3 73000 3 99.99 4 72000 3 99.99 5 66000 3 99.99 6 65000 3 99.99

In the above [Table 1], before treatment shows the amount of oil contained in the wastewater whole, and after treatment shows the amount of oil contained in the water discharged after treatment by the method of the present invention.

As seen above, it can be seen that the amount of oil before treatment is significantly reduced after treatment, and the remaining oil is collected in the form of flocs and finally treated by incineration as before.

The method of the present invention carried out in such a processing apparatus is shown in the flowchart of FIG. In addition, according to the method of the present invention, the results of treating heavy metals contained in the wastewater are shown below.

TABLE 2

heavy metal Before treatment (mg / ℓ) After treatment (mg / ℓ) Treatment efficiency (%) CD 100 0 (not detected) 100 Pb 100 0 (not detected) 100 Cr 100 0 (not detected) 100 Zn 100 0 (not detected) 100 Mg 100 0 (not detected) 100 Mn 100 0 (not detected) 100 Cu 100 0 (not detected) 100 Fe 100 0 (not detected) 100 Ni 100 0 (not detected) 100 Al 100 0 (not detected) 100 Sn 100 0 (not detected) 100

Table 2 shows the results of the electrolysis of the wastewater containing the heavy metals. It can be seen that almost all heavy metals contained in the wastewater are treated. Here, before treatment refers to the amount of heavy metals contained in the wastewater, and after treatment refers to the amount of heavy metals after removal through the method of the present invention.

The floc separated from the water can then be further processed by compressing the volume by using a compression device such as a filter press and the like and can be easily incinerated because the volume is small even when incinerated.

As described above, according to the present invention, there is an advantage of providing a wastewater treatment method which reduces treatment cost and reduces the risk of environmental pollution by separating and treating water from wastewater or waste oil containing oil, and furthermore, the water contained in wastewater or waste oil. Separation using electrolysis has the advantage of reducing the volume of waste water or waste oil and treating it.

Although the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that modifications and variations can be made within the spirit and scope of the invention, and such variations or modifications will belong to the appended claims. .

Claims (5)

A collection tank (1) provided with means operated by a motor (8) to uniformly stir the wastewater or the waste oil flowing into the state containing oil or heavy metals; A flow meter (3) for measuring the amount of waste water or waste oil discharged from the collection tank (1); Agglomerated colloid in the wastewater flowing out of the collection tank 1 and discharged in the form of a floc, separated into an outer tank 41 and an inner tank 42, a plurality of electrodes 34 on the upper side of the inner tank 42 A disintegration tank 4 having a space S formed between the outer tank 41 and the inner tank 42 and connected with a steam inlet a and a steam outlet b; Stirring tank (5) for agitating the wastewater separated by water and floc while flowing out from the decomposition tank (4) are separated from each other by agitation means operating at high speed and low speed; And It is characterized in that it consists of a settling tank 6 including a guide plate 61 for separating the water and the floc discharged from the stirring tank 5 to discharge the water to the drain passage 62 and discharge the floc to the upper side Oil and heavy metal treatment equipment in wastewater. 2. The oil and heavy metal treatment apparatus according to claim 1, wherein the oil and heavy metal treatment apparatus in the wastewater further comprises an activated carbon tank (7) for removing the flux discharged from the settling tank (6). 2. An apparatus for treating oil and heavy metals in waste water according to claim 1, wherein one or more burners (47) are provided at the outer bottom of the outer tank (41) to heat the inner tank (42). 2. The apparatus of claim 1, wherein the inner surface (46) of the inner tub (42) is coated with an insulating material. Agitating the oil by electrons and magnetic fields by stirring the wastewater containing oils and heavy metals with high charges and passing them through the electrodes; Floc formation by introducing a flocculant to increase the size of the flocculated fraction; Oxygen and hydrogen gas are adsorbed on the surface of the floc and float; Adding flocculant to the flocs and separating the flocs and water; And A method for treating oil and heavy metals in wastewater, characterized by discharging water and reducing the volume of flocs.