JPS5888095A - Treatment of exhaust gas from fermenting vat - Google Patents

Abstract

PURPOSE:To perform the effective utilization of exhaust heat and effectual deodorization, in changing sludge into compost, by withdrawing offensive odor- contg. gas formed in a fermenting vat and introducing it as aerating gas for the treatment of the sludge into an aerating cell. CONSTITUTION:By the operation of a blower 6, offensive odor-contg. exhaust gas formed in each fermenting chamber of a fermenting vat 1 is sprayed through the opened end of a withdrawing pipe 4 to the bottom of an aerating cell 5 so that residual oxygen in the exhaust gas is effectively utilized as oxygen necessary for oxidzing organic substance in raw water 7. At the same time, the exhaust gas sprayed to the bottom of the aerating cell 5 uniformly suspends active sludge in the aerating cell 5 to proper concentration and holds it under an aerobic condition. A large amount of ammonia contained in the exhaust gas can be absorbed in the raw water 7 by the aerating action during agitating and mixing, and effectively removed to a degree of 60-90%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating exhaust gas generated within a fermenter.

Generally, when sludge is composted, exhaust gas containing malodorous components is generated in the fermenter, but this exhaust gas contains 5
00~110007) p ammonia 0.1~12P
Since it contains malodorous components such as 711-methyl mercaptan and 0.5-5-57F methyl sulfide, it cannot be released into the atmosphere as it is. Conventionally, this exhaust gas has been deodorized by washing with water, acid washing, alkaline washing, chlorine treatment, and activated carbon treatment, but this increases the running cost of the equipment cost for removing fruit. It was causing this.

The present invention was proposed in view of the above-mentioned conventional drawbacks, and when sludge is composted, the exhaust gas containing malodorous components generated in the fermenter contains 10 to 19% oxygen. The key point is that this exhaust gas is led to the adjacent aeration IK and used as aeration gas for activated sludge treatment, and special equipment for deodorization treatment is installed.
The purpose of the present invention is to provide a method for treating exhaust gas from a fermenter, which enables effective use of exhaust gas and effective deodorization.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a process explanatory diagram showing one embodiment of the fermenter exhaust gas treatment method according to the present invention. In the figure, 1 is a fermentation tank, the inside of which is divided into an upper fermentation chamber and an upper fermentation chamber, each fermentation chamber contains sludge to be composted, and each fermentation chamber is supplied with air for fermentation. A fan 2 and piping 3 are provided for this purpose. 4 has one end communicating with each fermentation chamber,
The other end of the extraction pipe is an extraction pipe that opens at the bottom of the aeration tank 5 , a blower 6 is installed in the middle of the extraction pipe, and the tip of the extraction pipe 4 opens into the aeration tank 5 . In the figure, 7 indicates raw water supplied to the aeration tank 5, and 8 indicates treated water to be discharged.

In the present invention comprising the above process, when the blower 6 is driven, the exhaust gas containing bad fruit components generated in each fermentation chamber of the fermenter 1 is extracted via the extraction pipe 4, and the aeration tank 5
It is important to be guided by. The exhaust gas led to the aeration tank 5 is mixed with the fermentation air supplied to the fermentation chamber and contains 10 to 19% oxygen, and this exhaust gas is passed through the extraction pipe 40.
- By blowing out from the mouth end to the bottom of the aeration tank 5, the residual oxygen in the exhaust gas is effectively used as oxygen necessary for oxidizing the organic matter in the raw water 7, and the oxygen is discharged from the bottom of the aeration tank 5. The waste gas is used to suspend the activated sludge in the aeration tank 5 to a uniform and appropriate concentration, and to stir the inside of the aeration tank 5 to maintain an aerobic state. It will be effectively used as

In addition, the ammonia contained in large amounts in the exhaust gas, which was the main cause of bad odors, is absorbed while being stirred and mixed into the raw water 7 by aeration, and can be effectively removed to the extent of 60-90%. Become.

FIG. 2 shows another embodiment in which the position at which exhaust gas is introduced into the aeration tank 5 is changed. Generally, the raw water 7 supply side of the aeration tank 5 has a high BOI load and requires a large amount of oxygen. The exhaust gas extracted from the BOD
Aeration is ejected through the extraction pipe 4 to the outlet side of the treated water 8 where the load is low.

FIG. 5 shows an embodiment in which the concentration of exhaust gas introduced into the aeration tank can be controlled. In general, the amount of exhaust gas generated in the exhaust gas in the fermentation chamber and the oxygen concentration in the generated exhaust gas change depending on the properties of the sludge to be composted and the fermentation state. The concentration is measured by the concentration measuring device 10, and if the carbon dioxide concentration is high and the oxygen concentration is low, air is taken in from the air supply pipe 9 and mixed with the exhaust gas to increase the oxygen concentration to a predetermined value, and then the blower 6 The water is supplied to the aeration tank. In the figure, reference numeral 1112 indicates a control valve for adjusting the flow rate, which is opened and closed manually or automatically according to the measured value of the concentration measuring device 10.

FIG. 4 shows an embodiment in which deodorizing treatment is incorporated into the exhaust gas treatment method of the present invention. Depending on the properties of the sludge to be composted, the exhaust gas generated in the # generation chamber may be transferred to the blower 6.
Therefore, it may not be possible to sufficiently remove malodorous components in the exhaust gas simply by introducing the exhaust gas into the aeration tank 5 through the open end of the extraction pipe 4. In that case, the top surface of the aeration tank 5 is covered and sealed, and the gas in the aeration tank 5 is passed through the pipe 16 to the acid cleaning step 1.
4 and activated carbon treatment step 15, etc., to completely remove malodorous components. Even when a separate deodorization process is provided in this way, it goes without saying that aerating the exhaust gas into the aeration tank 5 is extremely effective as a pretreatment for deodorization. This shows an example in which the present invention is applied to a tank. In the figure, 16 is a deep aeration tank, and the raw water 7 supplied from the upper end of the downflow chamber 17 descends through the downflow chamber 17 and rises through the upflow chamber 18 from the lower end, and is discharged as treated water 8. A part of the treated water in the upper part of the upflow chamber 18 is
It is pumped up by the pump 19, returned to the upper end of the downflow chamber 17 via the return pipe 20, and recirculated. Then, the exhaust gas generated in the extraction tube 4 is ejected as aeration gas from the open end of the extraction pipe 4 into the raw water at the upper end of the downflow chamber 17 by the professional 76, but the ejected exhaust gas is discharged into the downflow chamber along with the raw water. 17 and the upward flow chamber 18 while being mixed by the turbulence effect and flowing while remaining in contact with the raw water for a long time. In this way, in the deep aeration tank 16, compared to the aeration tank 5 of the type shown in FIG. It is extremely effective as it can remove 70 to 95 tons of ammonia, which is the main cause of bad odors. In addition, in the illustrated embodiment,
Although only the exhaust gas generated in the fermentation chamber is used as the aeration gas in the deep aeration chamber 16, it is also possible to mix air into the exhaust gas to adjust the oxygen concentration and use it as the aeration gas, as shown in Figure 6. .

As specifically explained above, the present invention extracts the exhaust gas containing malodorous components generated in the generation tank when composting sludge, and guides it to the aeration tank as aeration gas for activated sludge treatment. This has the advantage that the exhaust gas in which oxygen remains can be effectively used as an aeration gas, and that malodorous components in the exhaust gas can also be effectively removed.

In addition, there is a general rule that there is a difference between a fermenter for composting sludge and an aeration tank for activated sludge treatment.Since they are often installed adjacent to the premises of a sludge treatment facility, the exhaust gas in the fermenter is guided to the aeration tank. The piping and other facilities for this process are extremely simple and have many advantages, such as the ability to significantly reduce the cost of deodorizing equipment for one exhaust gas.

[Brief explanation of the drawing]

Fig. 1 is a process explanatory diagram showing one embodiment of the fermenter exhaust gas treatment method according to the present invention, Fig. 2 is a process explanatory diagram showing another embodiment in which the aeration position by flue gas is changed, and Fig. 3 is an aeration diagram. Fig. 4 is an explanatory diagram of the process for controlling the concentration of exhaust gas led to the tank, Fig. 4 is an explanatory diagram of the treatment process incorporating deodorization processing into the exhaust gas treatment method of the present invention, and Fig. 5 is an explanation of the process when the present invention is applied to a deep aeration tank. It is a diagram. 1... Vertical fermentation tank, 2... Fan, 3... Piping,
4...Extraction pipe, 5...Aeration tank, 6...Prower, 7
... Raw water, 8... Treated water, 9... Air supply pipe, 1
0... Concentration measuring device, 11... Control valve, 12... Control valve, 13... Piping, 14... Acid cleaning process, 15...
・Activated carbon treatment process, 16 Deep aeration tank, 17...Downflow chamber, 18...Upflow chamber, 19...Pump, 20...
・Return pipe

Claims (1)

[Claims] Exhaust gas treatment for a fermenter, characterized in that exhaust gas containing malodorous components generated in the fermenter when composting sludge is extracted, and the gas is led to the aeration tank as aeration gas for activated sludge treatment. Method.