JPH06246294A - Waste water treatment device - Google Patents

Abstract

PURPOSE:To remove hydrogen sulfide out of an anaerobic bioreactor efficiently. CONSTITUTION:A device comprises an anaerobic bioreactor 1 and a stripping tank 3 for deaerating treated water from the anaerobic bioreactor 1 and exhausting the gas in the treated water. A circulating line is formed by the anaerobic bioreactor 1 and the stripping tank 3. The gas exhausted from the stripping tank 3 is introduced into a hydrogen sulfide oxidizing tank 5, and out of the gas, hydrogen sulfide is dissolved in ozone water in the hydrogen sulfide oxidizing tank 5 and removed therefrom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment apparatus for treating organic wastewater containing sulfate ions.

[0002]

Biochemical oxygen demand (BOD) in general
High-concentration organic wastewater containing several thousand mg / l or more is treated by anaerobic treatment. In the anaerobic biological treatment, when the exhaust gas contains a few thousand to several hundred mg / l of sulfate ion, hydrogen sulfide is generated by the sulfate-reducing bacteria, and this hydrogen sulfide causes biological inhibition. Therefore, conventionally, in order to remove hydrogen sulfide, coagulation and precipitation of calcium-based waste water is performed to remove sulfate ions, or generated hydrogen sulfide is removed by stripping and then sulfurized by a scrubber or a desulfurization tower. It is absorbing or adsorbing hydrogen.

[0003]

However, in the conventional technique, the consumption amount of the caustic soda aqueous solution used in the scrubber and the desulfurizing agent in the desulfurization tower increases, and the caustic soda aqueous solution needs to be neutralized after use. In addition, the desulfurizing agent needs to be treated as waste, which significantly deteriorates the treatment efficiency of the wastewater treatment apparatus as a whole.

The present invention has been made in consideration of the above points, and an object thereof is to provide a wastewater treatment apparatus capable of efficiently removing hydrogen sulfide and improving the overall treatment efficiency. And

[0005]

Means for Solving the Problems The present invention forms a circulation line between an anaerobic bioreactor and an anaerobic bioreactor for anaerobic biological treatment of organic wastewater containing sulfate ions, and The stripping tank that aerates the treated water from the anaerobic bioreactor and exhausts the gas in the treated water, and the gas that is exhausted in the stripping tank is introduced, and the ozone water that dissolves hydrogen sulfide in the exhausted gas is A wastewater treatment device comprising: a stored hydrogen sulfide oxidation tank.

[0006]

[Function] The organic wastewater is treated anaerobically in the anaerobic bioreactor, and the treated water from the anaerobic bioreactor is aerated in the stripping tank to exhaust the gas in the treated water and to be exhausted. The treated water is returned to the anaerobic bioreactor. The gas exhausted in the stripping tank is introduced into the hydrogen sulfide oxidation tank, and hydrogen sulfide in the substrate is corroded by ozone water.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a wastewater treatment apparatus according to the present invention. In FIG. 1, organic wastewater containing sulfate ions is sent to a raw water tank 10 via a raw water pipe 9. A raw water pump 11 and an anaerobic bioreactor 1 are sequentially connected to the raw water tank 10 via a pipe 17. Further, the anaerobic bioreactor 1 is aerated with the treated water from the anaerobic bioreactor 1 and is treated in the treated water. A stripping tank 3 for exhausting gas is connected. The stripping tank 3 and the anaerobic bioreactor 1 form a circulation line by a circulation pipe 18, and the circulation pipe 18 is provided with a circulation pump 4.

The stripping tank 3 has a sealed structure and has an aeration pipe 3a inside. And aeration pipe 3a
Is connected to the blower 2 and the blower 2 and the stripping tank 3
A circulation line is formed by the gas pipe 19 between and. Both the treated water and the gas in the stripping tank 3 are introduced into the hydrogen sulfide oxidation tank 5.

It is also possible to pass a part or all of the gas in the stripping tank 3 through the gas separator 15 to separate only hydrogen sulfide and introduce it into the hydrogen sulfide oxidation tank 5. The hydrogen sulfide tank 5 stores ozone water therein, and the ozone water dissolves hydrogen sulfide.

The gas other than hydrogen sulfide in the hydrogen sulfide oxidation tank 5 and the gas other than hydrogen sulfide separated by the gas separator 15 are sent to the gas holder 12 through the gas pipe 20 and stored therein, and then the gas boiler 13 is stored. To be effectively used as an energy source. Methane gas is mainly considered as the gas other than hydrogen sulfide sent to the gas holder 12.

On the other hand, the hydrogen sulfide oxidation tank 5 is connected to the ozone contact tank 7, and a circulation line is formed by a circulation pipe 21 between the hydrogen sulfide oxidation tank 5 and the ozone contact tank 7. A circulation pump 6 is provided in the circulation pipe 21, and an ozone generator 8 is connected to the ozone contact tank 7.

Next, the operation of this embodiment having such a configuration will be described. First, the wastewater in the raw water tank 10 is sent to the anaerobic bioreactor 1 by the raw water pump 11. Sulfate ions contained in the wastewater are reduced by sulfate-reducing bacteria in the anaerobic bioreactor 1 to hydrogen sulfide,
Further, the organic matter contained in the wastewater becomes methane gas and carbon dioxide gas by the anaerobic treatment. Next, the treated water, the gas dissolved in the treated water, and the gas in the gas phase are discharged from the anaerobic bioreactor 1 to the stripping tank 3, and then the anaerobic bioreactor 1 is stripped from the stripping tank 3. It is returned via the circulation pipe 18. In this case, methane gas can be effectively used as an energy source, but hydrogen sulfide inhibits microorganisms, and therefore needs to be removed from the anaerobic bioreactor 1.

Therefore, in the stripping tank 3, air is blown from the blower 2 to the aeration pipe 3a, and the stripping tank 3 is blown.
By aerating the inside, dissolved hydrogen sulfide is expelled from the treated water. The treated water from which hydrogen sulfide has been removed in this way is returned to the anaerobic bioreactor 1 from the stripping tank 3 via the circulation pipe 18 by the circulation pump 4. As a result, the hydrogen sulfide concentration in the anaerobic bioreactor 1 can be suppressed.

On the other hand, the mixed gas in the stripping tank 3 is passed directly or through the gas separator 15 into the hydrogen sulfide sulfide tank 5.
Be led to. Of the mixed gas introduced into the hydrogen sulfide oxidation tank 5, methane gas hardly dissolves in ozone water, and therefore flows directly from the gas pipe 20 to the gas holder 12,
After that, it is effectively used as an energy source of the boiler 13. On the other hand, since hydrogen sulfide gas is relatively easy to dissolve in ozone water, it dissolves in ozone water in the hydrogen sulfide oxidation tank 5 and becomes sulfur or sulfate ions due to the oxidizing action of ozone.

At the same time, the treated water from the stripping tank 3 flows into the hydrogen sulfide oxidation tank 5. And the treated water is
After coming into contact with ozone water in the hydrogen sulfide oxidation tank 5, it is further discharged to the outside through the ozone contact tank 7.

The ozone contact tank 7 is provided with an ozone generator 8
Ozone water is obtained by supplying ozone from the tank, and the ozone water is sent into the hydrogen sulfide oxidation tank 5 by the circulation pump 6.

When all of the mixed gas in the stripping tank 3 is passed through the gas separator 15 and led to the hydrogen sulfide oxidation tank 5, only hydrogen sulfide can be separated from the mixed gas in the gas separator 15. Then, this separated hydrogen sulfide is introduced from the gas separator 15 to the hydrogen sulfide oxidation tank 5, and a mixed gas other than hydrogen sulfide (mainly methane gas)
Directly to the gas pipe 20 without sending hydrogen to the hydrogen sulfide oxidation tank 5.
Can be guided to the gas holder 12. In this case, contact between methane gas and ozone can be prevented, and oxidation of methane gas and mixing of ozone into methane gas can be prevented.

According to the present embodiment, the mixed gas being treated is exhausted by the stripping tank 5, and only hydrogen sulfide in the exhausted mixed gas is ozone-oxidized in the hydrogen sulfide oxidation tank 5 to make it harmless. It is possible to effectively use other gases such as. Further, since the treated water and the ozone water are brought into contact with each other by the hydrogen sulfide oxidation 5 and the ozone contact tank 7, the treated water can be decolorized and deodorized.

Although the hydrogen sulfide oxidation tank 5 and the ozone contact tank 7 are separately provided in the above embodiment, a partition is provided in the same tank to form the hydrogen sulfide oxidation tank and the ozone contact tank. And may be provided respectively.

[0020]

As described above, since the treated water from the anaerobic bioreactor is aerated in the stripping tank and the gas in the treated water is exhausted, the treated water is returned to the anaerobic bioreactor. Hydrogen sulfide, which is harmful to microorganisms in the oxidative bioreactor, can be removed from the anaerobic bioreactor. Also, since hydrogen sulfide exhausted in the stripping tank is dissolved by ozone water after that,
Hydrogen sulfide can be removed efficiently.

[Brief description of drawings]

FIG. 1 is a schematic system diagram showing an embodiment of a wastewater treatment device according to the present invention.

[Explanation of symbols]

 1 Anaerobic bioreactor 3 Stripping tank 4 Circulation pump 5 Hydrogen sulfide oxidation tank 7 Ozone contact tank 15 Gas separator

Claims (2)

[Claims] 1. A anaerobic bioreactor that performs anaerobic biological treatment on organic wastewater containing sulfate ions, and a circulation line is formed between the anaerobic bioreactor and treated water from the anaerobic bioreactor. A stripping tank for aeration of the treated water to exhaust the gas in the treated water, and a hydrogen sulfide oxidation tank in which ozone water that dissolves hydrogen sulfide in the exhausted gas is introduced and the gas exhausted in the stripping tank is introduced. A wastewater treatment device comprising: 2. Between the stripping tank and the hydrogen sulfide tank,
The wastewater treatment apparatus according to claim 1, further comprising a gas separator that separates only hydrogen sulfide from the gas exhausted in the stripping tank and guides it to the hydrogen sulfide oxidation tank.