KR910003005B1 - Industrial waste water treating method and apparatus - Google Patents

Abstract

The waste water treating process comprises (1) collecting and settling waste water, (2) adding 1500-6000 mg/l oxidizer (NaOCl or ClO2) to waste water from the reservoir, (3) reacting the mixture in a vacuum tank for 5-45 mins. with agitation, (4) adding 350-700 mg/l flocculant (polyaluminum chloride) and 2-7 mg/l auxiliary agent, (5) separating sludge and treated water from the waste water, and (6) storaging and filtering the treated water with activated carbon to remove the remaining chlorine.

Description

Industrial wastewater treatment method and device

1 is a process chart according to the conventional industrial wastewater treatment method.

2 is a process chart according to the industrial wastewater treatment method of the present invention.

3 is a schematic diagram of a vacuum reaction tank used in the present invention.

* Explanation of symbols for main parts of the drawings

1, 11: storage tank 2: vacuum reaction tank

3: chemical tank 4: injection pump

5: flocculation tank 6: flotation tank

7: treated water tank 8: activated carbon filtration tank

12: pH adjusting tank 13: reaction tank

15: sedimentation tank

The present invention relates to a method for treating industrial wastewater by chemical and oxidation treatment, and a device thereof, and to dyeing and printing wastewater, slaughterhouses, slaughterhouse wastewater, and the like, which have not been completely treated by conventional industrial wastewater treatment methods. Emphasis is placed on the treatment of industrial wastewater, which reduces BOD and COD and completely removes contaminants (heavy metals, colors, etc.), especially color, thereby preserving the natural environment and reusing treated water. The tribal phenomenon can be broken.

In the conventional industrial wastewater treatment by chemical and oxidation treatment, the pH was adjusted by simple chemical injection, and then the wastewater was treated by precipitation or flotation through the reaction tank and the flocculation tank, but this has a limitation on the maximum efficiency of chemical treatment. In addition, the efficiency of pollutant removal was not high, and in addition, in the case of dyeing wastewater or printing wastewater, BOD and COD were not significantly reduced, and contaminants (heavy metal, color, etc.) were not completely removed, and color was also reduced. Since the efficiency of the effluent was little or high, there was an unreasonable shortcoming such as the inflow of nearby rivers or wastewater and the pollution of the natural environment. Not only that, the reuse of the treated water caused a shortage of industrial water.

Therefore, the present invention corrects the above-mentioned drawbacks as described above to economically and efficiently treat wastewater, thereby significantly reducing the pollution of the discharged wastewater, thereby enabling reuse of water and preventing pollution of the natural environment. The purpose is that, before treating the waste water in the coagulation tank, the wastewater mixed with the oxidant in the vacuum reaction tank in which one or several fully sealed reaction tanks are connected in series is added to the agitator. After the vacuum reaction for a predetermined time while stirring, and then flocculation in the flocculation tank, and then separating the slurry (Sludge) and the treated water in the flotation tank to reduce the contaminants and increase the color removal efficiency.

That is, in the conventional industrial wastewater treatment method, as shown in FIG. 1 of the accompanying drawings, a pH adjusting tank 12 for adjusting pH of the wastewater is installed after the storage tank 11 into which the wastewater is collected and introduced. The contaminant was removed by passing through the settling tank 15 or the floating tank 15 'via the 13 and the coagulation tank 14.

However, in the conventional industrial wastewater treatment method as described above, the industrial wastewater is treated after adjusting the pH by a simple chemical injection, and thus, the BOD and the printed wastewater in the case of dyed wastewater or printed wastewater, which are the biggest problems in the industrial wastewater treatment. Not only did it not significantly reduce COD, but also it could not completely remove contaminants (heavy metals, colors, etc.), and its treatment efficiency was extremely low and it was not economical.

The industrial wastewater treatment method of the present invention will be described with reference to FIG.

Storage tank (1) in which the wastewater is collected and disposed in the next step, instead of the conventional pH adjusting tank, a vacuum-tight tank (2) with a completely closed structure is provided, and an oxidizing agent chemical tank (3) is added to the vacuum reaction tank (2). The oxidant in the chemical tank 3 is mixed with the wastewater flowing into the reaction tank 2 by the pump 4 to be supplied.

At this time, NaOCl or ClO ₂ was used as the oxidant to be mixed with the wastewater flowing into the vacuum reaction tank, and the reaction treatment time in the vacuum reaction process was treated for 5 to 25 minutes.

In addition, the flocculant added in the flocculation treatment step is PAC (Poly Aluminum Chloride) (trade name sold by Unico, Korea) as the flocculating aid. AN-905SH, FA-920SH, FO-7290, FO-414OSH, FO -435OSH, FO-4490SH and the like (trade names sold by Korea, Yeongil Chemical Co., Ltd. and Baekwang Chemical Co., Ltd.) were used.

Inside the reaction tank (2) was installed a stirrer (21), the outside was installed a discharge valve 22 for saturation gas discharge to install a pressure gauge (23) for gas measurement, the discharge valve (22) The waste water can be completely reacted in the vacuum reaction tank while preventing the release of oxygen oxygen (O ₂ ) of the oxidant supplied by mixing with the waste water in the closed vacuum reaction tank.

If a conventional open reaction tank is used instead of the vacuum reaction tank in this process, since the complete reaction cannot occur, the efficiency falls below 50%, and thus there is no use value.

In the present invention, when the wastewater is collected and flows into the storage tank 1, the pump is pumped to the operation in the central control room (MCC) (not shown) by the detection of the level switch, and the storage tank is operated while all the machines are operating. The wastewater of (1) starts to flow into the reaction tank (2), and at the same time, the injection pump (4) connected to the chemical tank (3) is operated so that the oxidant in the chemical tank (3) is supplied and mixed with the waste water. After flowing into the furnace reaction tank (2), the reaction was stirred by the stirrer (21) in the completely sealed vacuum reaction tank (2) to complete the reaction, and then introduced into the coagulation tank (5), at this time, the flocculant and flocculation introduced The adjuvant is fed to the flotation tank 6 through the flocculation process.

The wastewater introduced into the flotation tank 6 is separated into treated water and sludge, and the treated water is overflowed to the treated water tank 7 and then discharged after being completely treated through the activated carbon filtration tank 8 and finally discharged. Will be made.

On the other hand, the sludge treated in the flotation tank 6 is treated according to a conventional sludge treatment method.

The treated water flowing out of the treated water tank 7 can be reused in water such as toilets by the remaining Cl in the oxidant supplied to the reaction tank 2 and reacted.

When reusing for other purposes, the effect of Cl remaining in the treated water can be predicted, and the adsorption and removal of Cl through the activated carbon tank can completely remove the Cl remaining in the treated water to increase the efficiency of wastewater purification. In addition, these treated water can be fully recycled into your industrial water.

In the practice of the present invention, a flotation tank must be used after the flocculation tank, and when the precipitation tank is used, no wastewater treatment efficiency can be obtained.

This is because the gas (Gas) remains in the sludge coagulated in the coagulation tank by the oxidant introduced into the reaction tank, so that the sludge does not precipitate and floats.

The industrial wastewater treatment method of the present invention will be described in detail by way of examples.

Example 1

When raw sand is produced by processing raw materials, wastewater is generated during bleaching, refining and dyeing, and the generated wastewater is 100 to 150㎥ / day.

In this case, the concentration of wastewater is

pH 4-14 (Aver 4.4)

BOD = 1000-1500 mg / l

COD = 1000mg / ℓ

Suspended Soil (SS) = 200 mg / l.

When the wastewater was first treated by chemical treatment and secondly by the conventional industrial wastewater treatment method by activated sludge method, the following problems occurred.

(1) Lack of residence time due to insufficient capacity of existing plant

(2) Poor post-treatment due to high water temperature (60 ~ 98 ℃) of raw waste water

(3) the release of toxic substances Cr ⁺⁶ and the intermittent release of H ₂ O ₂

(4) Unprocessed pollutants (heavy metals, etc.) in final treated water and residual color

(5) BOD and COD are still high.

However, as a result of treating the wastewater by the industrial wastewater treatment method of the present invention, the following results were obtained.

At this time, NaOCl or ClO ₂ was used as the oxidant to be mixed with the wastewater flowing into the vacuum reaction tank, and the reaction treatment time in the vacuum reaction process was treated for 5 to 25 minutes.

In addition, P.A.C (Poly Aluminum Chloride) was used as the flocculant added in the flocculation process and AN-905SH or FA-920SH or FO-4140SH was used as the flocculent aid.

[Table 1] (Unit: mg / l)

Example 2

When the chemical analyte concentration of the raw wastewater is 240 mg / ℓ, COD, efficiency and degree of color removal when the industrial wastewater treatment method of the present invention is treated in the same amount as [Table 2] [Table 2] It is described in.

At this time, the same oxidizing agent, flocculant and flocculent aid as in Example 1 were used.

[Table 2] (Unit: mg / l)

Example 3

When the chemical analyte concentration of the raw wastewater is 260 mg / ℓ, the COD, efficiency and degree of color removal when the industrial wastewater treatment method of the present invention is treated in the same amount as [Table 3] [Table 3] It is described in.

At this time, the same oxidizing agent, flocculant and flocculent aid as in Example 1 were used.

Table 3 (Unit: mg / L)

As shown in Table 1, 2, 3 it can be seen that there is a difference in the removal efficiency of the COD and color (Color) according to the concentration of the oxidizing agent and flocculant.

That is, by adjusting the input amount of the oxidizing agent and the flocculant to an appropriate amount as necessary, such as the pollution degree of the wastewater and the recycling or discharge of the treated water, it is possible to receive the required treated water or recyclable industrial water.

For example, when raw waste water Q = 100 m 3 / day, 200 to 300 L of oxidizing agent and 40 to 60 L of coagulant can be completely removed to COD and color, thereby improving wastewater purification efficiency.

Claims (4)

A method of treating industrial wastewater by chemical and oxidation treatment, wherein the wastewater is treated through the following process and then the treated water is discharged or recycled as water. (1) Storage process for collecting and sedimenting wastewater. (2) A vacuum reaction step of mixing 1500-6000 mg / l of an oxidizing agent into a waste water supplied from a storage tank, introducing the same into a vacuum reaction tank, and then vacuum-reacting for 5 to 45 minutes with stirring. (3) A flocculation step of coagulating by adding 350 to 700 mg / l of flocculant and 2 to 7 mg / l of flocculent aid to the wastewater fed out after the vacuum reaction. (4) Flotation process to separate the wastewater introduced from the coagulation tank into sludge and treated water. (5) A treated water storage process for storing the treated water separated from the flotation tank. (6) Activated carbon filtration step of adsorbing Cl remaining in the treated water. The method for treating oxidized wastewater according to claim 1, wherein NaOCl or ClO ₂ is used as the oxidant when the oxidant is mixed and stirred in the effluent supplied to the vacuum reaction tank. The industrial wastewater treatment method according to claim 1, wherein P.A.C (Poly Aluminum Chloride) is used as a flocculant added to the wastewater in the flocculation process. When the wastewater is treated by the industrial wastewater treatment method according to claim 1, a reaction tank for mixing the wastewater supplied from the storage tank with the oxidant and flowing the reaction therein is installed, and a stirrer 21 is installed inside, and the upper side is sealed outside. It consists of a vacuum reaction tank (2) equipped with a pressure gauge (23) and a gas discharge valve (22) so that a complete vacuum reaction can take place inside the reaction tank. Industrial wastewater treatment apparatus characterized in that configured to be automatically discharged through the valve.

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