JPH09155359A - COD component removal method - Google Patents

Abstract

(57) [PROBLEMS] To provide a technology capable of removing COD of wastewater at a high removal rate at a practical cost. SOLUTION: The method is characterized by supplying COD-containing water to a cathode chamber of a diaphragm electrolysis tank, introducing it to an anode chamber of a diaphragm electrolysis tank, and electrolytically oxidizing it while supplying ozone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to effectively oxidize and decompose hardly biodegradable COD (for example, a yellowish brown chromaticity component in biologically treated water of human waste) in various kinds of waste water into carbon dioxide gas and water. Technology that can

[0002]

2. Description of the Related Art Conventionally, as a method for oxidative decomposition of COD, an ultraviolet-hydrogen peroxide combination method, an ultraviolet-photocatalyst combination method, an ultraviolet-ozone oxidation combination method, an ozone-hydrogen peroxide combination method, etc. have been known. In all cases, the COD removal rate was inferior in spite of the high treatment cost, and there was no practical use in fields other than the ultrapure water production field.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a new technology capable of removing COD of waste water at a high removal rate at a practical cost.

[0004]

The present invention is characterized in that after COD-containing water is supplied to the cathode chamber of the diaphragm electrolysis tank, it is introduced into the anode chamber of the diaphragm electrolysis cell and electrolytically oxidized while supplying ozone. Is the way to do it.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The structure and operation of the present invention will be described in detail with reference to FIG. Raw water 1 in cathode chamber 3 of diaphragm electrolyzer 2
To supply. The electrodes are preferably platinum-plated titanium electrodes for both the cathode and the anode. The diaphragm 8 is an organic microfiltration membrane (MF
Membranes) are preferred. Cathode chamber 3 in which water is electrolyzed to generate hydroxide ions by the following electrochemical reaction in cathode chamber 3
PH of 10 is raised to about 10-11. H ₂ O + e ⁻ → 1 / 2H ₂ + OH ⁻ Next, the high-PH cathode chamber outflow water 4 is introduced into the anode chamber 5 and electrolytically oxidized while supplying ozone 6. As a result, the anode chamber 5
Oxidation reaction, high pH ozone oxidation reaction (COD
The ozone oxidation reaction of 1) is promoted at high pH), and the combined reaction of chlorine oxidation reaction proceeds to highly decompose and remove COD to obtain treated water 7. One of the reasons why a high removal rate of COD is obtained is that when ozone is supplied to the anode chamber while performing electrolytic oxidation of the diaphragm, a hydroxy radical having a strong oxidizing action is generated from the ozone at the anode interface due to an electrochemical reaction. It seems to be. COD is hardly removed even if ozone is supplied without electrolysis. In addition, electrolysis without supplying ozone is more effective than the ozone-only method, but the COD removal effect is considerably inferior to the method of the present invention.

[0006]

[Examples] A verification test of the present invention is carried out for 3 months under the conditions shown in Table 2 with respect to treated human waste water treated by UF membrane (average water quality is shown in Table 1) according to the process shown in FIG. It was Table 1 Appearance Yellow water temperature like beer 32 degrees pH 7.2 SS 0 mg / l BOD 8 mg / l COD 142 mg / l Table 2 Raw water supply to diaphragm cell tank cathode chamber 5 l / d Cathode chamber volume 0 .5 l Anode chamber capacity 0.5 l Electrode area 60 cm ² Current 35 mA Voltage 6 V Ozone addition amount 120 mg / l

Table 3 shows the quality of treated water. The results of ozone alone treatment and electrolysis alone treatment are also shown. Table 3 Present invention Ozone alone Electrolysis alone pH 6.7 7.5 7.5 6.1 SS (mg / l) 0 5 0 BOD (mg / l) 2 8 3 COD (mg / l) 9.8 92 68 No external appearance Colorless slightly yellow

[0008]

According to the present invention, the following effects can be obtained. 1. COD that cannot be biologically decomposed can be effectively removed by the ozone oxidation-diaphragm electrolysis combined method. 2. The effect of increasing the pH in the cathode compartment of the diaphragm electrolyzer can be utilized for the efficiency of ozone oxidation. (Ozone oxidation of COD is high p
Promoted by H)

[Brief description of the drawings]

FIG. 1 shows the structure of a diaphragm electrolysis cell used in the present invention.

[Explanation of symbols]

 1 COD-containing raw water 2 Diaphragm electrolyzer 3 Cathode (cathode chamber) 4 Cathode chamber outflow water 5 Anode (anode chamber) 6 Ozone 7 Treated water from which COD has been removed 8 Diaphragm

Claims (1)

[Claims] 1. A method comprising supplying COD-containing water to a cathode chamber of a diaphragm electrolysis tank, introducing it to an anode chamber of a diaphragm electrolysis cell, and electrolytically oxidizing it while supplying ozone.