KR20000053693A - Wastewater treatment method using microwave and the apparatus thereof - Google Patents

Abstract

PURPOSE: A leachate treatment method and apparatus thereof using high-frequency waves is provided, which is characterized in that high-frequency waves(microwave) is used to activate generation of hydroxyl radical compared with conventional chemical treatment using hydrogen peroxide. CONSTITUTION: Ferrous compound in a ferrous compound storage tank(24) and hydrogen peroxide in a hydrogen peroxide storage tank(25) are injected into leachate by chemical pump(26)(27). Then, hydroxyl radical is formed by the reaction of ferrous ion and hydrogen peroxide. In a high-frequency waves reactor(30), high-frequency waves is generated by a high-frequency waves generator(31), so generation of hydroxyl radical is activated by dielectric phenomenon. A baffle(35) and an air mixer(36) are installed in reaction compartment(34) to equalize oxidation reaction.

Description

Wastewater treatment method and apparatus using high frequency

The present invention relates to a method and apparatus for treating wastewater containing hardly decomposable organic substances, such as waste leachate. Specifically, in the treatment of wastewater containing hardly decomposable organic substances such as leachate with hydrogen peroxide as an oxidizing agent, The present invention relates to a method for improving the oxidizing power of hydrogen peroxide and a wastewater treatment apparatus developed to apply the method efficiently.

Due to industrial development and increasing consumer life, the amount of pollutants produced by humans is increasing. Therefore, many investments and efforts are being made to develop technologies for the treatment of these pollutants, and the wastewater treatment methods currently developed and used can be roughly classified into physical treatment methods, chemical treatment methods, and biological treatment methods.

Among them, Fenton oxidation method, which is a chemical treatment method using strong oxidation power of radical hydroxide (· OH) generated by reacting divalent iron ion with hydrogen peroxide, was used as a method for treating hardly degradable contaminants. Various attempts have been made to increase the efficiency. In developed countries such as the United States, photolysis oxidation systems using ultraviolet rays and hydrogen peroxide have been developed.

However, these systems have not yet completely solved the problem of efficiently treating wastewater containing high concentrations of hardly decomposable organic pollutants at low cost, thus efficiently treating a large amount of wastewater inevitably accompanied by industrial development. There is a continuous demand for the development of wastewater treatment methods.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of treatment efficiency for wastewater containing hardly decomposable organic contaminants of the conventional wastewater treatment method, and to efficiently treat organic wastewater such as leachate at a simple and low cost. It is to develop and provide a device.

1 is a schematic diagram showing a wastewater treatment process of the present invention,

2 is a structural diagram showing a wastewater treatment plant employing the wastewater treatment process and apparatus of the present invention;

Figure 3a is a plan view showing the structure of a high frequency reactor of the wastewater treatment apparatus of the present invention,

Figure 3b is a cross-sectional view showing the structure of the high frequency reactor of the wastewater treatment apparatus of the present invention.

* Description of the main parts of the drawings *

10: sump tank 11: sump pump

12: Air Mixer 20: Chemical Mixing Tank

21 pH pH (pH-STAT) 22 Acidic chemical tank

23: chemical pump 24: ferrous chemical tank

25: hydrogen peroxide chemical tank 26: chemical pump

27: chemical pump 28: stirrer

30: high frequency reactor 31: high frequency generator

32: waveguide 33: power supply

34: reaction chamber 35: baffle

36: Air mixer (AIR MIXING machine) 40: pH adjusting tank

41: pH STAT (pH-STAT) 42: chemical pump

43: alkali chemicals tank 44: stirrer

50: flotation 51: sludge withdrawal

60: flow adjustment tank 61: air mixer (AIR MIXING equipment)

62: flow rate adjustment tank pump 70: contact aeration tank

80: sedimentation tank 90: flow meter

Accordingly, the present invention, in the oxidative wastewater treatment method using hydrogen peroxide as the oxidant, by developing a wastewater treatment method and apparatus employing a high frequency generator in the reactor in addition to using the divalent iron ions used in the Fenton method for the activation of hydrogen peroxide The treatment efficiency of pollutants in the waste water is improved to effectively remove microorganisms and hardly decomposable organic substances that are not possible with conventional chemical treatment.

In the wastewater treatment method according to the present invention, as described in FIG. 1, after adjusting the raw wastewater stored in the sump to an appropriate pH and administering hydrogen peroxide and hydrogen peroxide activators as oxidizing agents, an oxidation reaction using high frequency oxidizing agent activity in a high frequency generator is performed. The wastewater treatment apparatus according to the present invention comprises a high frequency generator, a wastewater inlet, a wastewater outlet, a waveguide, and a high frequency reactor equipped with a reaction chamber so as to generate microwave (MICROWAVE). The high frequency reactor according to the preferred embodiment includes an air mixer (AIR MIXING group) for improving the reaction efficiency and a baffle protruding from the inner wall of the reaction chamber.

Hereinafter, an example of the wastewater treatment method according to the present invention will be described in detail with reference to FIGS. 1 and 2 of the accompanying drawings.

First, the collected wastewater is collected in the water collecting tank 10 and then mixed with the air mixer 12, which is a mixture of contaminants in the wastewater. The concentration is uniformed to improve the treatment efficiency during the reaction. The waste water uniformly mixed in the sump is transferred to the chemical mixing tank 20.

The pH stat 21 of the chemical mixing tank 20 detects the pH of the wastewater and automatically operates the chemical pump 23 to inject acidic chemicals (eg, sulfuric acid) from the chemical tank 22 into the wastewater in the pH adjusting tank. It is adjusted to a pH appropriate for the oxidation reaction. In the chemical mixing tank, a stirrer 28 is installed to uniformly mix wastewater and acid. The pH-adjusted wastewater contains a chemical capable of providing ferric ions stored in the ferric chemical tank 24 and the hydrogen peroxide chemical tank 25, for example ferric sulfate or ferrous chloride and hydrogen peroxide (H ₂ O ₂ ). It is injected by the operation of the chemical pumps 26 and 27.

In the high frequency reactor 30, hydrogen peroxide reacts with ferric ions (Fe ⁺⁺ ) due to a high frequency dielectric phenomenon, and a reaction in which radical hydroxide (· OH) is generated is promoted. An oxidation reaction occurs to remove the material. Hydrogen peroxide has a very high dielectric constant of 89.2 (0 ° C). When irradiated with microwaves at high frequencies, it absorbs microwaves of high energy and efficiently oxidizes them.

The high frequency reactor 30 in which the oxidation reaction is performed is composed of a high frequency generator (magnetron) 31, a waveguide 32, a power supply unit 33, and a reaction chamber, and the reaction chamber 34 is made of uniform mixing of wastewater in the reaction chamber. A baffle 35 and an air mixer 36 are provided to protrude toward the inside of the reaction chamber so that the oxidation reaction can be made uniformly and efficiently. The high frequency irradiated by the high frequency generator may use one of the industrially available frequency bands, that is, the I.S.M frequency band (950 MHz band, 2,450 MHz band, 5,800 MHz band, and 24,125 MHz band).

The wastewater treated in the high frequency reactor is conveyed to the pH adjusting tank 40 under natural flow. The pH adjuster 40 is also equipped with a pH STAT (pH-STAT) 41, and detects the pH of the waste water and automatically operates the chemical pump 42, thereby storing alkali chemicals stored in the chemical tank 43 (caustic). Soda) is injected into the wastewater. Moreover, the stirrer 44 provided in the pH adjustment tank functions to mix waste water and a chemical uniformly. The injection of alkaline chemicals adjusts the pH of the waste water to pH 6.5-8.3, which meets the legal discharge limits.

When alkali chemicals are injected into the waste water, the iron ions contained in the waste water form iron salts by the reaction shown in Scheme 1 below, and the suspended solids cause the electrical equilibrium between particles to collapse, causing the particles to aggregate together. This creates a mass of suspended solids (FLOC).

Fe (OH) ₃

The pH is adjusted in the pH adjusting tank 40, and the wastewater in which the floc material floc is formed is transferred to the flotation tank 50, and the sludge is withdrawn from the flotation tank through the flotation operation 51. ) Is sent to the flow rate adjustment tank (60).

The treated water introduced into the flow regulating tank 60 is uniformly mixed by using an air mixer 61 to equalize the concentration of contaminants, and then operated by the flow regulating pump 62 to operate the contact aeration tank. 70).

In the contact aeration tank 70, organic pollutants remaining in the high frequency reactor are treated without biological treatment by the action of microorganisms.

The treated water passing through the contact aeration tank 70 is transferred to the settling tank 80 to precipitate the desorption microorganisms, and the supernatant is discharged through the flow meter 90.

Example 1

Treatment of leachate, which is one type of hardly degradable wastewater, by using the process and apparatus described above was as follows.

[Experimental Conditions]

High Frequency Reactor

1kW, 2450MHz

[Drug dosage]

H ₂ SO ₄ : 10PPM

FeSO ₄ : 1,000PPM

H ₂ O ₂ : 1,000PPM

Contaminant Concentrations in Raw and Treated Water [Unit: PPM] Item Wastewater Treated water concentration COD 630 79 BOD 290 53

Example 2

The experimental values of the wastewater treatment when the wastewater treatment method according to the present invention is applied to leachate, one of the hardly degradable wastewaters, are compared with the wastewater treatment result by the oxidative wastewater treatment method by the conventional Fenton method.

[Experimental Conditions]

[Invention] [Fenton method]

High Frequency Reactor

1kW, 2450MHz

[Drug Input] [Drug Input]

pH 4 pH 4

FeSO ₄ : 1,000PPM FeCl ₃ : 1,200PPM

H ₂ O ₂ : 1,000PPM H ₂ O ₂ : 1,500PPM

Contaminant Concentration in Water Treated by the Invention and Fenton Method [Unit; PPM] Item Wastewater Fenton Method The present invention COD 630 268 79 BOD 290 118 53

As seen through the above embodiment, the present invention has a significantly higher efficiency of removing organic pollutants than conventional oxidative wastewater treatment, and when combined with biological treatment, wastewater containing hardly decomposable organic pollutants at a low cost. There is an effect that can be processed efficiently.

Claims (3)

A chemical wastewater treatment method in which an organic pollutant is oxidized and treated by using hydrogen peroxide as an oxidant, and a chemical wastewater treatment method using a method of irradiating high frequency microwave (MICROWAVE) as a method for enhancing the oxidation activity of hydrogen peroxide is used. Way. A wastewater treatment apparatus for carrying out the wastewater treatment method of claim 1, comprising a chemical treatment apparatus comprising a wastewater inlet, a wastewater outlet, a high frequency generator, a waveguide, and a reaction chamber. The wastewater treatment apparatus according to claim 2, wherein the high frequency reactor includes a baffle which protrudes toward the inside of the reaction chamber from the air mixer and the inner wall of the reaction chamber as a means for increasing the reaction efficiency by uniform mixing of the wastewater. .