JP2001232383A - Method for treating organic wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating organic wastewater by which the organic wastewater is highly effiently treated in a short time. SOLUTION: The method for treating the organic wastewater wherein the organic wastewater is supplied to an MnO2 packed layer 2 in which MnO2 catalyst is packed while ozone gas is diffused from the lower part of the MnO2 packed layer 2 and the treated water passed through the MnO2 packed layer 2 is taken out is characterized in that the treatment is carried out in the presence of a calcium component to activate the reaction of ozone and the MnO2 catalyst and pre-treatment for removing phosphorus which inhibits the reaction of the ozone and the MnO2 catalyst is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to secondary sewage water,
The present invention relates to a method for efficiently treating organic wastewater from organic wastewater such as leachate from a landfill, rivers, human waste, and industrial wastewater.

[0002]

The organic waste water was supplied to the ART MnO ₂ packed bed while supplying ozone from below the MnO ₂ catalyst MnO ₂ packed layer filled takes out a treated water having passed through the MnO ₂ packed bed prior The method of treating organic wastewater is a method of generating hydroxy radicals (OH.) By the reaction of ozone and a MnO ₂ catalyst to oxidatively decompose organic wastewater more strongly than ozone. However, organic wastewater sometimes contains a large amount of hardly decomposable components, and the conventional method has poor treatment efficiency and requires time for treatment. Sometimes occurred.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems and to provide a method for treating organic wastewater which can efficiently treat organic wastewater in a short time. Things.

[0004]

Means for Solving the Problems A method for treating organic wastewater according to the first invention, which has been made to solve the above-mentioned problems, comprises Mn
Mn while supplying ozone to the MnO ₂ packed bed filled with O ₂ catalyst
O ₂ The organic waste water was supplied to the packed bed, the treatment method of organic wastewater to retrieve the treated water was passed through the MnO ₂ packed bed,
It is characterized by treating organic wastewater in the presence of a calcium component. As means for the presence of calcium component, means for adding a calcium compound to the organic wastewater, means for filling the added catalyst a calcium compound to MnO ₂ in MnO ₂ packed bed, a calcium compound as a carrier of MnO ₂ catalyst The catalyst using the support containing Mn
Means for filling the O ₂ -filled layer can be used.

Further, the method of treating organic waste water of the second invention, the organic waste water was supplied to the MnO ₂ packed bed while supplying ozone into MnO ₂ packed bed MnO ₂ catalyst is filled, MnO ₂ packed A method for treating organic wastewater for extracting treated water that has passed through the formation, wherein phosphorus is removed from the organic wastewater as pretreatment.

Conventionally, the calcium component is removed as CaCO ₃ because it causes scale. However, the method of treating organic wastewater of the present invention contradicts conventional common sense to remove organic wastewater in the presence of calcium component. By the treatment, the reaction between ozone and the MnO ₂ catalyst is activated, the ratio of hydroxy radicals having strong oxidizing power generated by this reaction is increased, and organic wastewater is rapidly oxidized and decomposed to increase the treatment efficiency. be able to. In addition, the method for treating organic wastewater of the present invention can also enhance the treatment efficiency by quickly oxidizing and decomposing organic wastewater by removing phosphorus that inhibits the reaction between ozone and the MnO ₂ catalyst.

[0007]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing an apparatus for carrying out the method for treating organic wastewater of the present invention, wherein 1 is a reaction tower, 2 is a MnO ₂ packed bed provided inside the reaction tower 1, honeycomb or comb-like, granules or other molded MnO ₂ catalyst shape or a honeycomb shape or a pectinate shape, granules or other catalyst supporting MnO ₂ catalyst carrier molded into shape, is filled. An ozone gas diffuser 3 is provided below the MnO ₂ packed layer 2.

The upper portion of the reaction tower 1 is hermetically closed to form an exhaust gas collecting structure, and an exhaust ozone treatment tower 4 for decomposing unreacted ozone gas in the collected exhaust gas is provided. Organic wastewater containing COD components and the like is supplied into the reaction tower 1 from the top of the MnO ₂ packed bed 2 through a raw water supply line 5 and is taken out from a treated water discharge line 6 at the bottom of the tower.

The organic wastewater supplied into the reaction tower 1 is MnO ₂
While flowing down the packed bed 2, the COD component in the organic wastewater is oxidatively decomposed more strongly than ozone by generating hydroxyl radicals by the reaction between ozone and MnO ₂ . The following reaction proceeds in this part, and the COD component is oxidized and decomposed.

[0010]

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In the present invention, by treating organic wastewater in the presence of a calcium component, the ratio of hydroxy radicals having strong oxidizing power is increased, and organic wastewater is rapidly oxidized and decomposed to increase the treatment efficiency. Although the concentration can be increased, it is desirable that the concentration of the calcium component in the organic wastewater be 500 mg / L or more in order to exert the effect effectively. In addition, by removing phosphorus from organic wastewater as a pretreatment, the reaction between ozone and the MnO ₂ catalyst can be activated to increase the treatment efficiency of organic wastewater. 1 mg / L phosphorus concentration in wastewater
It is desirable to be less than.

In the first embodiment of the present invention, a calcium compound is added to organic wastewater, and the organic wastewater is supplied into the reaction tower 1. The calcium compound is desirably a water-soluble one such as calcium chloride or calcium nitrate. The method of adding the calcium compound is to add an aqueous solution in which the calcium compound is dissolved, or use a method in which the crystalline calcium compound is directly added to the organic wastewater. be able to.

A second embodiment of the present invention is to fill the added catalyst a calcium compound to MnO ₂ in MnO ₂ packed layer, a third embodiment of the present invention, carrier MnO ₂ catalyst Is to fill a MnO ₂ packed bed with a catalyst using a support containing a calcium compound. In these cases, the calcium compound may be a calcium oxide, a calcium salt, or the like. The mixing ratio of the calcium compound is desirably 20% or more by weight with respect to MnO ₂ as a catalyst.

In a fourth embodiment of the present invention, a pretreatment for removing phosphorus from organic wastewater is performed. As a pretreatment method, a conventional method such as a coagulation precipitation method using an aluminum salt or an iron salt or biological dephosphorization can be used.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. A first test was conducted by applying the method for treating organic wastewater of the present invention to leachate from a landfill. The test was conducted when the organic wastewater was passed through the reaction tower 1 filled with the MnO ₂ catalyst as it was, and when a calcium compound was added to the organic wastewater so that the calcium concentration in the organic wastewater was 2000 mg / L. Conduct,
Calcium chloride was used as the calcium compound.
At this time, the test was performed under the conditions of an ozone addition amount of 100 mg / L and a water temperature of 20 ° C., and a change in the COD concentration was measured. Table 1 shows the test results.

[0016]

[Table 1]

In Table 1, No. 1 is raw water before treatment, which is an organic wastewater having a calcium concentration of 100 mg / L and a COD concentration of 30 mg / L. No. No. 2 is No. This is a comparative example in which organic wastewater having the property 1 is treated in a treatment time of 1 hour, and the COD removal rate is 45%.
%. For this reason, no. As seen from Comparative Example 3, the processing time had to be increased to 4 hours in order to increase the COD removal rate to 70%, and the processing efficiency was low. On the other hand, in the case where the calcium compound was added to the organic wastewater, In Example 4, ozone and Mn were increased by increasing the calcium concentration to 2000 mg / L.
The reaction with the O ₂ catalyst was activated, and the COD removal rate could be increased to 67% in 1 hour of the treatment time.

Next, before supplying the organic wastewater into the reaction tower 1, a second test of performing a pretreatment for removing phosphorus from the organic wastewater was performed. As the pretreatment, a coagulation treatment method in which ferric chloride was added was used. The test conditions such as the catalyst used were the same as those in the first test. Table 2 shows the test results.

[0019]

[Table 2]

In Table 2, No. 5 is raw water before treatment, which is an organic wastewater with a phosphorus concentration of 1 mg / L and a COD concentration of 30 mg / L. No. No. 6 is a comparative example in which organic wastewater was treated with a conventional MnO ₂ catalyst without performing pretreatment, and the COD removal rate was 45%.
Was low. On the other hand, no. 7 uses a conventional MnO ₂ catalyst as a catalyst and performs a pretreatment to reduce the phosphorus concentration to 0.03.
mg / L, but the COD removal rate was 55%.
Could be raised to In addition to the pretreatment, the calcium compound contains 40% by weight of the MnO ₂ catalyst
No. 3 in which a calcium component was present using a MnO ₂ catalyst. 8
In Example 1, the COD removal rate could be increased to 75% by the treatment for 1 hour due to the synergistic effect of dephosphorization and addition of the calcium component.

[0021]

As described above, according to the method for treating organic wastewater of the present invention, the treatment efficiency of organic wastewater can be increased and the treatment time can be shortened, thereby increasing the amount of treatment. In addition to the above, there is an advantage that the necessity of increasing the number of reaction towers is reduced and the size of the reaction tower can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an apparatus for practicing the present invention.

[Explanation of symbols]

1 reaction tower, 2 MnO ₂ packed bed, 3 ozone gas diffuser, 4 waste ozone treatment tower, 5 raw water supply line, 6 treated water discharge line

Continued on the front page F term (reference) 4D050 AA02 AA13 AA16 AA20 AB11 BB02 BC04 BC06 BD02 CA16 CA17 4G069 AA02 AA03 BB04A BB04B BB08A BB12A BC09A BC62A BC62B BD12A CA05 CA07 CA10 DA06

Claims (5)

[Claims] 1. A MnO ₂ catalyst the organic waste water was supplied to the MnO ₂ packed bed while supplying ozone into MnO ₂ packed layer filled, MnO ₂
An organic wastewater treatment method for extracting treated water passed through a packed bed, wherein the organic wastewater is treated in the presence of a calcium component. 2. The method according to claim 1, wherein a calcium component is present by adding a calcium compound to the organic wastewater. 3. A method of treating organic waste water according to claim 1, wherein the presence of a calcium component by filling a catalyst prepared by adding a calcium compound to MnO ₂ in MnO ₂ packed bed. 4. A method of treating organic waste water according to claim 1, wherein the presence of a calcium component by filling the catalyst using carrier containing calcium compound as MnO ₂ catalyst carrier of the MnO ₂ packed bed. 5. The MnO ₂ catalyst is an organic waste water was supplied to the MnO ₂ packed bed while supplying ozone into MnO ₂ packed layer filled, MnO ₂
A method for treating organic wastewater, wherein phosphorus is removed from the organic wastewater as a pretreatment, wherein the treated water is taken out of the treated water that has passed through the packed bed.