KR102197246B1 - Ststem for neutralizing concrete wastewater - Google Patents

Abstract

The present invention relates to an apparatus for neutralizing concrete wastewater, comprising: a neutralizing agent generation unit; a neutralization processing unit; and a control unit for operation thereof, wherein the neutralizing agent generation unit is operated according to a command of a control device when the concrete wastewater flows into the neutralization processing unit, and a neutralizing agent is generated and supplied to the neutralizing processing unit.

Description

Concrete wastewater neutralization treatment device {STSTEM FOR NEUTRALIZING CONCRETE WASTEWATER}

The present invention relates to an apparatus for neutralizing concrete wastewater, and more specifically, it occurs through the manufacture, pouring and curing of concrete, cutting, processing, and finishing of hardened concrete at construction sites such as tunnels, roads, bridges, and buildings. It relates to an apparatus for neutralizing concrete wastewater that allows the concrete wastewater to be treated directly on site.

A large amount of concrete wastewater is generated at the construction site. For example, washing water is used to finish the concrete floor, and a large amount of washing water is also used to clean the interior of the mixer after pouring concrete using a mixer.

In addition, a large amount of waste concrete is generated in construction works such as redevelopment and reconstruction work, and civil works such as expansion, repair, and demolition of roads and bridges, and a large amount of water is used during the crushing process. Concrete wastewater has a strong alkalinity of pH 12~13, so if they penetrate into the ground through rainwater or groundwater, they will pollute the water quality and have enormous adverse effects on the natural environment.

Therefore, concrete wastewater must be neutralized to about pH 7 and then discharged.

For the neutralization of such strong alkaline wastewater, sulfuric acid was used as a neutralizing agent in the past, but due to the toxicity of sulfuric acid, the licensing process for the use is complicated and the maintenance is difficult. Recently, the pH is lowered by mixing and reacting carbon dioxide with concrete wastewater. This is mainly being studied.

As an example,'an alkaline wastewater neutralization treatment tank using carbon dioxide gas and a neutralization treatment method of alkaline wastewater using the same' has been proposed as Registered Patent Publication No. 10-1973789.

As shown in FIG. 1, the alkaline wastewater neutralization treatment tank includes: a treatment tank body 10 in which alkaline wastewater (raw water) and carbon dioxide gas are mixed to cause a neutralization reaction; A raw water inlet 20 provided on one side of the neutralization treatment tank body; A treated water outlet 30 provided on the other side of the neutralization treatment tank body; A carbon dioxide gas injection line 40 provided in the raw water inlet 20; And a stirrer 50 for stirring the raw water and carbon dioxide gas.

Therefore, carbon gas injected into line 40, the carbon dioxide gas is H reacts with the alkaline waste water flowing into the treatment tank body 10 through the ^- treatment tank body through by generating, these raw water inlet (20) ^-, HCO ₃ Ca ^+2, contained in the alkaline waste water flowing into the (10) 2 (OH) ^- is able to reducing the pH and by the reaction.

However, in order for this neutralization reaction to be carried out efficiently, carbon dioxide gas must be in sufficient contact with alkaline wastewater. For this purpose, in Registration No. 10-1973789, the agitation of alkaline wastewater and carbon dioxide gas is faster by using a stirrer 50. In addition, an acid substrate 60 for dispersing carbon dioxide gas may be provided at the raw water inlet 20 so that alkaline wastewater and carbon dioxide gas can sufficiently contact each other.

However, registration number 10-1973789 has a structure in which carbon dioxide gas is supplied from the outside, and for this purpose, a high-pressure compressed storage tank is required. In addition, the supply of carbon dioxide gas must be performed at the same time as the supply of alkaline wastewater, but since carbon dioxide stored in a solidified or liquefied state at high pressure must go through a roof tile and a pressure reducing device, it is not easy to supply it in a timely manner. Therefore, registration number 10-1973789 recommends that an additional sulfuric acid injection line be provided in case the supply of carbon dioxide gas is not available. Moreover, the high supply price of carbon dioxide manufactured for industrial use as described above acts as a factor to increase the cost of neutralization treatment of alkaline wastewater.

KR 10-1973789 B1

The present invention is to solve the above problems of the prior art, so that the supply of a neutralizing agent for neutralization of concrete wastewater can be made quickly, accurately and inexpensively, and it is easy to maintain and can be used directly at construction sites. It is intended to provide a device for neutralizing concrete wastewater that can minimize the installation scale.

According to the most preferred embodiment of the present invention for solving the above problems, the neutralizing agent generation unit, the neutralization treatment unit, and a control unit for their operation, wherein the neutralization agent generation unit of the control device when concrete wastewater flows into the neutralization treatment unit. There is provided a neutralization treatment device for concrete wastewater, characterized in that the neutralization agent is generated and supplied to the neutralization treatment unit while operating according to the command.

At this time, the neutralizing agent generator is composed of a power supply device, a plasma generator, and a burner device, and the power supply device applies power according to the command of the control device when the concrete wastewater flows into the neutralization treatment unit. Can work.

In addition, the neutralizing agent generated by the neutralizing agent generator may be carbon dioxide gas, or a mixture of carbon dioxide gas and nitrogen oxide, and in the latter case, nitrogen oxide is generated by using air as a plasma forming gas.

In addition, a heat exchange device for reducing the temperature of the generated neutralizing agent to room temperature may be further provided in the neutralizing agent generating unit, and the thermal energy obtained thereby can be treated by drying the sludge in the sludge treatment unit.

In addition, the neutralization treatment unit is composed of a grit flow control unit, a line mixer and a purification unit, and the grit flow control unit is composed of a grit tank and a flow control tank, and a water level sensor and a supply pump are installed in the flow control tank, and the flow rate set by the water level sensor When this is detected, the supply pump is operated according to the command of the control device to supply the concrete wastewater from the flow control tank to the line mixer, and at the same time, the neutralizing agent generator is operated, and the neutralizing agent generated thereby is supplied to the line mixer. Concrete wastewater can be neutralized in the mixer section.

In addition, the purification unit may be configured as a complex tank that allows the entire process of reaction, agglomeration, and precipitation to occur at the same time, or may be divided into a reaction coagulation tank in which reaction and agglomeration are performed at the same time, and a settling tank to precipitate the solidified sludge. , By providing an air injection means in the lower portion of the composite tank and the reaction coagulation tank, it is possible to achieve efficient stirring.

Since the present invention is to generate a purification agent immediately when treating concrete wastewater, it does not require facilities such as a storage tank to store the purification agent, and neutralization treatment such as minimizing the size of a treatment tank for purification of neutralized concrete wastewater. Since the device can be miniaturized, it is easy to move, so it can be easily installed at construction sites to treat concrete wastewater economically and environmentally.

In addition, since the present invention can quickly generate a high-concentration purification agent by using a plasma generating device, concrete wastewater can be treated efficiently, and the sludge can be treated after drying with heat energy obtained by a heat exchange device. It makes it possible to secure hygiene and economic feasibility.

1 is a conceptual diagram of an alkaline wastewater neutralization treatment tank according to the prior art.
2 is a conceptual diagram of the structure of the neutralization treatment apparatus of the present invention.
3 is a graph showing the concentration of nitrogen oxides generated according to the ratio of nitrogen and oxygen.
4 is a graph confirming the minimum point of energy cost used to generate nitrogen oxides.
5 is a graph showing the neutralization rate by the neutralization mechanism of the present invention.
6 is a conceptual diagram of a purification unit of a neutralization treatment apparatus according to an embodiment of the present invention.
7 is a conceptual diagram of a purification unit of a neutralization treatment apparatus according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in the case of obscuring or obscuring the technical idea of the present invention due to a detailed description of a known configuration in the description of the present invention, a description of the known configuration will be omitted.

2 is a conceptual diagram showing the structure of a concrete wastewater neutralization apparatus according to an embodiment of the present invention.

As shown in FIG. 2, the neutralization treatment apparatus of the present invention includes a neutralization agent generation unit 200, a neutralization treatment unit 300, and a control unit 400 for operating them.

The neutralization treatment apparatus of the present invention neutralizes the high alkalinity of concrete wastewater using carbon dioxide gas, but it is an important technical feature that carbon dioxide gas for this can be directly supplied by the neutralizing agent generator 200. Therefore, the neutralization treatment apparatus of the present invention eliminates the need for the installation of a carbon dioxide gas storage tank as in the prior art, thereby minimizing the installation size and improving mobility, thereby making it easier to use in construction sites that exist only for a certain period of time.

For this purpose, the neutralizing agent generating unit 200 generates a gas for neutralization of alkalinity through a chemical reaction such as carbon dioxide, and supplies the gas to the neutralization processing unit 300. At this time, the generation of carbon dioxide gas, etc. is prevented from being polluted due to excessive generation by allowing concrete wastewater (raw water) to be generated only when flowing into the neutralization treatment unit 300.

The neutralizer generator 200 includes a power supply device (not shown), a plasma generator 210, and a burner device 220.

The power supply device is a device for applying power to the plasma generating device 210 and the burner device 220, as described above, according to the command of the control unit 400 when concrete wastewater flows into the neutralization treatment unit 300 Power is applied so that the plasma generating device 210 and the burner device 220 can be operated immediately. The fuel for combustion of the burner device 220 is sufficient if it is a hydrocarbon material including LPG and kerosene, but methane gas is most preferably used.

Combustion in the state in which plasma is formed generates carbon dioxide gas more rapidly than normal combustion and increases concentration thereof. For example, in the case of combustion of methane gas, in the case of general combustion, methane gas reacts with oxygen molecules to generate carbon dioxide gas, but in the case of combustion using the plasma generator 210, the methane gas reacts with oxygen ions to generate carbon dioxide gas. Because it is generated, a more rapid reaction occurs and a high concentration of carbon dioxide gas is generated.

On the other hand, nitrogen oxides including NO ₂ , NO, N ₂ O ₂ , N ₂ O, etc., are converted into nitric acid-type acids in water, and thus may play a role in reducing the strongly alkaline pH of concrete wastewater. Accordingly, in another embodiment of the present invention, a mixture of carbon dioxide gas and nitrogen oxide is used as a neutralizing agent by generating nitrogen oxide in addition to the carbon dioxide gas by the neutralizing agent generator 200.

The graph of FIG. 3 shows the concentration of nitrogen oxides generated according to the ratio of nitrogen and oxygen. According to this, it can be seen that when the ratio of nitrogen and oxygen is the ratio of air, about 3.7, nitrogen oxides are generated at the maximum.

Meanwhile, in a general combustion method, nitrogen oxides are not easily produced by simply injecting air, and nitrogen oxides may be generated by separately supplying fossil fuels thereto. However, the additional supply of fossil fuels poses a cost burden and economic problem.

Therefore, in a more preferred embodiment of the present invention, by using air as a plasma forming gas, nitrogen oxides can be generated thereby improving economic efficiency.

In addition, in the case of combustion by the plasma generating device 210, more than 10 times more OH ^- is generated than in the case of general combustion, and accordingly, the combustion temperature rises rapidly, and thus the generation of nitrogen oxides is further increased. Is done. In addition, as shown in Fig. 4, the higher the concentration of nitrogen oxides (blue line), that is, the larger the amount of nitrogen confinement generated, the lower the input energy per unit generation amount (J/L), so that high economic efficiency can be achieved. do.

As described above, the carbon dioxide gas and nitrogen oxide generated in the neutralizing agent generating unit 200 are sent to the neutralizing unit 300, and the neutralizing unit 300 rapidly neutralizes concrete wastewater through the following two neutralization mechanisms. .

(Neutralization mechanism 1)

CO ₂ (g) → CO ₂ (aq) ;CO ₂ solvation

_{CO 2 (aq) + H 2} O ↔ H 2 CO 3 (aq) ↔ HCO 3 - + CO 3 2-; CO 2 dissociation (carbonation)

_{Ca (OH) 2 (s)} ↔ Ca 2+ + OH -; Ca (OH) 2 dissociation

^{Ca 2+ + OH - + H +} + CO 3 2- ↔ CaCO 3 (s) + H 2 O; Carbon mineralization

(Neutralization mechanism 2)

NO ₂ (g) → NO ₂ (aq); NO ₂ solvation

_{NO 2 (aq) + H 2} O ↔ HNO 3 (aq) ↔ H + + NO 3 -; NO 2 dissociation (carbonation)

_{Ca (OH) 2 (s)} ↔ Ca 2+ + OH -; Ca (OH) 2 dissociation

^{Ca 2+ + OH - + H +} + NO 3 - ↔ CaNO 3 (s) + H 2 O; Nitrogen mineralization

In order to rapidly implement the above-described neutralization mechanism, a neutralizing agent such as carbon dioxide gas generated in the neutralization generating unit must be sufficiently mixed with the concrete wastewater. To this end, the present invention configures the line mixer unit 230 in the neutralization treatment unit 300 so that the flow of neutralization treatment can be made continuously without interruption while omitting the configuration of a power device such as a stirrer for mixing the neutralization agent and concrete wastewater. To be.

On the other hand, the carbon dioxide gas and nitrogen oxide generated by the neutralizing agent generating unit 200 have a high temperature of 700 to 1100°C. The high temperature of the neutralizing agent slows the chemical reaction with the concrete wastewater, thereby effectively reducing the neutralization mechanism. It acts as a factor that prevents it from happening.

Therefore, in another embodiment of the present invention, a heat exchange device 240 is provided in the neutralization treatment device. The high temperature carbon dioxide gas and nitrogen oxide generated by the neutralizer generating unit 200 are reduced to room temperature by the heat exchange device 240 and enter the line mixer unit 230 to which concrete wastewater is supplied, The above-described neutralization mechanism becomes more efficient. At this time, the heat energy obtained by reducing the temperature of the neutralizing agent in the heat exchange device 240 enables sanitary sludge treatment without incurring additional costs, as described later.

5 is a graph showing the neutralization rate by the neutralization mechanism of the present invention. According to this, it can be seen that a strong alkaline wastewater having a pH of 12 or higher is lowered to about pH 7 in about 70 seconds, and the neutralization rate is rapidly and efficiently achieved.

Concrete wastewater that has undergone the neutralization step causes reaction, agglomeration and precipitation to occur in sequence, and it is common to install each treatment tank for this, but in the neutralization treatment unit 300 of the present invention, at least a part of the reaction, agglomeration and precipitation By minimizing the number of treatment tanks required by simultaneous operation, economical efficiency and mobility are further improved, and as described above, by drying the sludge with thermal energy obtained by reducing the temperature of the neutralizing agent in the heat exchanger 240, the sanitary performance of the sludge treatment. We promote efficiency.

The neutralization treatment unit 300 of the present invention includes the line mixer unit 230 as described above, and includes a sedimentation flow rate adjustment unit 310 and a purification unit 320.

The sedimentation flow rate adjustment unit 310 includes a sedimentation tank 311 and a flow rate adjustment tank 312.

In the concrete wastewater generated at the construction site, various concrete crushed products, sand, stone dust, etc. are mixed with the concrete wastewater at a high concentration, and the grit tank 311 precipitates and filters them first.

The concrete wastewater that is first filtered through the grit tank 311 is sent to the flow control tank 312 so that the flow rate supplied to the neutralization treatment unit 300 is maintained at a constant level.

A filter member 313 should be installed between the grit tank 311 and the flow control tank 312 so that large particles such as pulverized material are not included in the concrete wastewater supplied through the flow control tank 312.

A water level sensor 314 and a supply pump 315 are installed in the flow control tank 312. When the flow rate set by the water level sensor 314 is detected, the control unit 400 operates the supply pump 315 so that the concrete wastewater can be supplied to the line mixer unit 230. At the same time, the control unit 400 operates the neutralizing agent generating unit 200, and more specifically, causes the power supply to apply power to the plasma generating device 210 and the burner device 220 so that the plasma generating device 210 and the The burner device 220 is operated, and the neutralizing agent generated thereby is supplied to the line mixer unit 230. Therefore, in the line mixer unit 230, the concrete wastewater reacts with the neutralizing agent so that the pH is about 7 at a strong alkalinity of at least 12.

Of course, it is preferable that the purifying agent generated by the neutralizing agent generating unit 200 is supplied to the inside of the line mixer unit 230 while the temperature is reduced to room temperature through a heat exchanger.

Although not shown, spiral blades are installed inside the line mixer unit 230 to efficiently agitate concrete wastewater and neutralizers.

Concrete wastewater that has passed through the line mixer unit 230 is sent to the purification unit 320.

The purification unit 320 is a part that purifies the concrete wastewater while sedimenting fine particles such as sludge, which are contained in the neutralized concrete wastewater, and may be composed of a complex tank 321 in which reaction, aggregation, and precipitation are simultaneously performed. In addition, it may be composed of a reaction coagulation tank 322 for reaction and agglomeration, and a settling tank 323 for sedimenting the solidified sludge.

6 is an illustration of a case where the purification unit 320 is constituted by the complex tank 321 described above. Although only one composite tank 321 may be installed, by installing a plurality of it, the treatment of concrete wastewater can be continuously performed without stopping.

For example, when two complex tanks 321 are installed as shown in FIG. 6, while the purification process of reaction, coagulation, and precipitation in one side of the complex tank 321 is performed, the other side of the complex tank 321 is subjected to the following purification. For the process, the neutralized concrete wastewater from the line mixer 230 is filled up to the required level, so that the complex tanks 321 on both sides can alternate between the purification process and the filling process, thereby allowing a single complex tank 321 Unlike ), it does not cause the problem of stopping the purification process until the concrete wastewater is filled.

In the composite tank 321, an administration device 324 for administering a coagulant such as aluminum sulfate and a polymer coagulant aid such as a polymer is installed.

Fine particles in the concrete wastewater form flocs while agitating with the coagulant. The coagulation aid is a polymer crosslinking of these fine flocs to form larger and heavier coarse flocs so that the sedimentation function is completed.

The coagulation reaction and coarsening of the flocs are efficiently carried out through sufficient agitation of concrete wastewater, a coagulant, and a coagulant aid. To this end, an air spraying means 325 is provided in the lower part of the composite tank 321. That is, in the present invention, air is blown into the concrete wastewater through the air injection means 325 to generate air bubbles, so that the concrete wastewater can be sufficiently stirred and contacted with the coagulant and the coagulant aid. Of course, a braid stirrer (not shown) may be additionally added thereto.

The air injection means 325 is composed of a plurality of air pipes 325a and injection ports 325b formed at regular intervals in each air pipe 325a. The air pipe 325a receives air through a supply pipe 326 connected to the air compressor 327.

FIG. 7 shows an example in which the purification unit 320 is provided with a reaction coagulation tank 322 in which reaction and coagulation are performed at the same time, and a sedimentation tank 323 for sedimenting the solidified sludge.

In that the reaction coagulation tank 322 is provided with the above-described coagulant and coagulant aid dispensing device 324, as well as air injection means 325 in the lower part, and a blade stirrer can be additionally added thereto. It is not different from the composite tank 321 according to the embodiment of FIG. 6.

However, the embodiment of FIG. 7 is different from the embodiment of FIG. 6 in that the sludge of the coarse floc can easily settle by allowing the concrete wastewater to stagnate without generating eddy currents.

On the other hand, the chemical reaction by the flocculant requires a pH of 4.5 to 8. Therefore, the present invention aims to neutralize the concrete wastewater to about pH 7 in the line mixer 230, but the pH may exceed 8 depending on the alkalinity of the concrete wastewater, etc., in the present invention, in the neutralizing agent generator 200 By allowing some of the generated neutralizing agent to be supplied directly to the complex tank 321 or the reaction coagulation tank 322, an additional neutralization action may be performed in the complex tank 321 or the reaction coagulation tank 322.

At this time, the neutralizing agent supplied to the composite tank 321 or the reaction coagulation tank 322 is mixed with air through a supply pipe 326 provided for supply of air, and the composite tank 321 or the reaction coagulation tank 322 Can be supplied to.

The solidified sludge filtered in the complex tank 321 or the sedimentation tank 323 is dehydrated and treated in the sludge treatment unit 330, and the separated and purified concrete wastewater (purified water) is partially used for dissolution of the coagulant and coagulant aid. The rest is discharged to complete the treatment of concrete wastewater.

In addition, the dewatered sludge can be dried by the heat energy obtained through the heat exchanger 240 as described above, and the present invention enables hygienic and efficient treatment of the sludge.

In the above, the present invention has been described in detail with reference to specific embodiments, but the embodiments are only examples for making the present invention easier to understand, so those of ordinary skill in the art will have the scope of the technical idea of the present invention. It is obvious that it will be possible to implement this in various ways. Therefore, such modified examples will be said to belong to the scope of the present invention as described in the claims.

200; Neutralizer generating unit 210; Plasma generator
220; Burner device 230; Line Mixer
240; Heat exchange device 300; Neutralization
310; Grit flow rate adjustment unit 311; Treadmill
312; Flow control tank 313; Filter member
314; Water level sensor 315; Supply pump
320; Purification unit 321; Compound tank
322; Reaction coagulation tank 323; Settling tank
324; Dosing device 325; Air injection means
325a; Air pipe 325b; Nozzle
326; Supply pipe 327; Air compressor
330; Sludge treatment unit 400; Control unit

Claims (8)

Consisting of a neutralizing agent generating unit 200 and a neutralizing treatment unit 300 and a control unit 400 for their operation, the neutralizing agent generating unit 200 is a control unit 400 when concrete wastewater flows into the neutralization unit 300 A device that neutralizes and treats concrete wastewater by generating a neutralizing agent while being operated according to the command of and supplying the neutralization treatment unit 300,
The neutralizing agent generating unit 200 is composed of a power supply device, a plasma generating device 210 and a burner device 220,
When the concrete wastewater flows into the neutralization treatment unit 300, the power supply device applies power according to the command of the control unit 400, thereby operating the plasma generating device 210 and the burner device 220,
The neutralization treatment unit 300 includes a grit flow rate adjustment unit 310, a line mixer unit 230, and a purification unit 320,
The sedimentation flow rate adjustment unit 310 is composed of a sedimentation tank 311 and a flow rate adjustment tank 312,
A water level sensor 314 and a supply pump 315 are installed in the flow control tank 312, and when the flow rate set by the water level sensor 314 is detected, the supply pump 315 is operated according to the command of the control unit 400. The concrete wastewater from the flow control tank 312 is supplied to the line mixer unit 230, and at the same time, the neutralizing agent generating unit 200 is operated, and the neutralizing agent generated thereby is supplied to the line mixer unit 230, and the line mixer The device for neutralizing concrete wastewater, characterized in that the concrete wastewater is neutralized in the unit 230.
delete The method of claim 1,
The neutralizing agent for concrete wastewater, characterized in that the neutralizing agent generated by the neutralizing agent generating unit 200 is carbon dioxide gas.
The method of claim 1,
The neutralizing agent generated by the neutralizing agent generating unit 200 is a mixture of carbon dioxide gas and nitrogen oxide,
The nitrogen oxide neutralization apparatus for concrete wastewater, characterized in that it is generated by using air as a plasma forming gas.
The method of claim 1,
The neutralizing agent generator 200 is a concrete wastewater neutralization treatment device, characterized in that the heat exchanger 240 is provided to reduce the temperature of the generated neutralizing agent to room temperature.
delete The method of claim 1,
The purification unit 320 is composed of a complex tank 321 that allows the entire process of reaction, agglomeration and precipitation to occur at the same time, and an air injection means 325 is provided below the complex tank 321 Concrete wastewater neutralization treatment device.
The method of claim 1,
The purification unit 320 is composed of a reaction coagulation tank 322 in which reaction and coagulation are performed at the same time, and a settling tank 323 for sedimenting the solidified sludge,
An apparatus for neutralizing concrete wastewater, characterized in that an air injection means (325) is provided below the reaction coagulation tank (322).

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