JP3146275B2 - Anaerobic wastewater treatment method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anaerobic sewage treatment method and apparatus capable of improving the quality of treated water.

[0002]

2. Description of the Related Art In an anaerobic sewage treatment apparatus for purifying sewage water by utilizing the action of anaerobic microorganisms, sludge is settled and deposited on a tank bottom because it is not aerated and stirred. For this reason, the deposited sludge is corroded and decomposed into methane gas, hydrogen sulfide and the like by anaerobic microorganisms such as methane bacteria and sulfur bacteria, and this has caused a bad smell. Furthermore, the anaerobic microorganisms in the sedimented sludge do not come into contact with the sewage, so that the sewage treatment by the anaerobic microorganisms was not sufficiently performed. Conventionally, in order to correct such a problem, a device having a submerged stirring blade in a sewage treatment tank has been proposed.

[0003]

However, in an anaerobic sewage treatment apparatus provided with a submerged stirring blade, metal materials such as a motor and a rotating shaft are often used to rotate the submerged stirring blade. , There was a problem in durability. It was also expensive in terms of cost. In contrast, the present inventor has conducted intensive studies in order to improve the quality of treated water in the anaerobic sewage treatment apparatus, can have your anaerobic sewage treatment equipment so as not to anaerobic microbes inactive It has been found that the supply of air improves the quality of the treated water.

[0004]

Anaerobic wastewater processing method according to claim 1, wherein according to the present invention SUMMARY OF] is allowed to flow into the water to be treated of domestic wastewater such as the one anaerobic sewage treatment tank, the one anaerobic purifies sewage by anaerobic microorganisms in the sewage treatment tank, fouling
In the sewage treatment method of sedimentation and separation of the treated sewage and sludge by sedimentation and sedimentation of sewage, sewage agitation that does not bring anaerobic microorganisms into an inert state in an anaerobic sewage treatment tank. It is a method of supplying waste air to treat wastewater.

An anaerobic sewage treatment method according to a second aspect of the present invention is a method for intermittently supplying the air in the anaerobic sewage treatment method according to the first aspect.

According to a third aspect of the present invention, there is provided the anaerobic sewage treatment method according to the second aspect, wherein the amount of air supplied in the anaerobic sewage method is 0.5 to 10 g / m 2 in terms of oxygen.
A method that is ^three minutes.

[0007] Anaerobic sewage treatment apparatus according to claim 4, wherein according to the present invention, allowed to flow into the water to be treated, such as domestic wastewater to an anaerobic sewage treatment tank, anaerobic in the one anaerobic sewage treatment tank Purifies sewage by germs and deposits sludge
In this way, in a method of sedimentation and separation of treated sewage and sludge , a diffuser is disposed at a lower position in an anaerobic sewage treatment tank, and a diffuser is provided. Is a device to which sewage stirring air is supplied to such an extent that the anaerobic microorganisms are not made inactive.

An anaerobic sewage treatment apparatus according to a fifth aspect of the present invention is the anaerobic sewage treatment apparatus according to the fourth aspect, wherein the air is intermittently supplied.

In the anaerobic sewage treatment apparatus according to claim 6 of the present invention, the amount of air in the anaerobic sewage treatment apparatus according to claim 5 when supplying air is 0.5 to 10 g in terms of oxygen amount.
/ M ³ minutes.

[0010]

According to the method for treating anaerobic sewage according to the present invention as set forth in claim 1, since air for stirring sewage is supplied into the anaerobic sewage treatment tank to such an extent that the anaerobic microorganisms are not inactivated, sedimentation and sedimentation occur. The anaerobic microorganisms in the sludge and the organic matter in the sewage work more uniformly, and the quality of the treated water can be improved.

According to the anaerobic sewage treatment apparatus according to the present invention, the anaerobic sewage treatment method is an apparatus for performing the above-described anaerobic sewage treatment method. In particular, since a diffuser is provided at a lower position in the treatment tank, The effect of stirring the accumulated sludge is high, and there is less danger of corrosion as compared with the case where a conventional underwater stirring blade is used, so that the durability is high and the cost is low.

[0012] By intermittently supplying air, for example, the anaerobic microorganisms can be prevented from being inactivated and the quality of treated water can be easily improved.

In particular, in order to perform the anaerobic treatment while sufficiently exhibiting the effect of stirring the sludge, the amount of oxygen as described in the third and sixth aspects is preferable.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the method and apparatus for treating anaerobic sewage according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing a case where the present invention is applied to an anaerobic sewage treatment apparatus of a sedimentation separation type. An anaerobic sewage treatment apparatus 1 shown in FIG. 1 has a main body composed of a treatment tank 2, and water to be treated such as domestic wastewater flows into a manhole 3 opened on the upper surface of the treatment tank 2 by the operation of a pump (not shown). Sewage treatment by anaerobic microorganisms is performed, and after anaerobic treatment, the effluent is discharged from a discharge port 4 opened on the upper wall surface of the treatment tank 2. The sludge that has accumulated in the processing tank 2 is drawn out from the upper part of the processing tank 2 by drawing in a bellows hose and discharged.

An air diffuser 5 for stirring the inside of the tank with air is installed below the processing tank 2. The air supplied to the air diffuser 5 is supplied from an air supply device 6 provided outside the tank through an air supply pipe 7. In the drawing, the air diffuser 5 is placed slightly above the bottom of the processing tank 2, but may be placed on the bottom surface.

Here, the air supply device 6 is operated intermittently at predetermined time intervals. Specifically, for example, air is supplied only once every 30 to 120 minutes for 1 to 60 seconds. Of course, this value varies depending on the size of the treatment tank 2, the quality of the inflowed wastewater, the air supply capacity of the air supply device 6, and the like. Is appropriately adjusted so as to increase the removal rate. In addition, if the amount of air is small, the effect of stirring the sludge is not sufficient,
On the other hand, if the amount of air is large, anaerobic treatment will not be performed.
g / m ³ minutes is preferred.

Thus, in the anaerobic sewage treatment apparatus having the above-mentioned structure, SS is set by gravity sedimentation in the inflow sewage.
(Suspended Sludge: refers to organic matter such as suspended solid matter, sand, and sludge) is removed. On the other hand, the intermittent operation of the air supply device 6 causes agglomeration of SS in the treatment tank 2 by the action of air. Since the effect is further promoted and the sedimentation speed is improved, the SS removal rate is improved.
The experimental results showing the removal rate of SS are shown in Table 1 below. The term “intermittent stirring” in Table 1 indicates a case where air supply is performed once every 60 minutes (10 seconds) in this experiment.

[0018]

[Table 1]

Further, the air is stirred by the supply of the air, and the frequency of contact between the anaerobic sludge and nutrients such as organic matter in the inflowing sewage is increased. As a result, BOD, COD, nitrogen, phosphorus, n-hexane and the like are consequently increased. The components were similarly treated efficiently, and the removal rates of BOD, COD and total nitrogen could be increased as shown in Tables 2, 3 and 4 below. In Tables 2 to 4, the term "intermittent stirring" means the same conditions as in Table 1, and the same water sampling examples A to G as those used in the experiments in Table 1 are used. . Tables 2 to 4 show the experimental results showing the removal rates of BOD, COD and total nitrogen.

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

Further, since the methane gas and hydrogen sulfide were scattered outside the tank while the concentration of methane gas and hydrogen sulfide was low due to the intermittent stirring, it was also confirmed in this experiment that the offensive odor was reduced.

FIG. 2 is a schematic sectional view showing a case where the present invention is applied to an anaerobic sewage treatment apparatus 8 of a filter bed type. In this figure, the water to be treated is introduced from the lower part of the treatment tank 2 and a filter bed 9 for fixing anaerobic sludge is provided in the center part, but the other configuration is the same as that of FIG.

[0025]

As described above, according to the anaerobic sewage treatment method and apparatus of the present invention, the removal rates of BOD, COD and nitrogen can be increased. The odor has also been reduced. Furthermore, since the anaerobic sewage treatment apparatus is provided with a diffuser, there is an advantage that, compared to the case where an underwater stirring blade is provided, there is less corrosion problem, the durability is improved, and the apparatus can be implemented at low cost. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an anaerobic sewage treatment apparatus according to the present invention.

FIG. 2 is a schematic sectional view showing another example of the anaerobic sewage treatment apparatus according to the present invention.

[Explanation of symbols]

 1,8: Anaerobic sewage treatment device 2: Treatment tank 5: Aeration device 6: Air supply device 7: Air supply pipe

Claims (6)

(57) [Claims] 1. A allowed to flow into the water to be treated of domestic wastewater such as the one anaerobic sewage treatment tank, purifies sewage by anaerobic microorganisms in the one anaerobic sewage treatment tank, is precipitated deposited sludge
It is to, in the wastewater treatment method of the treated sewage sludge and the sedimentation separation makes <br/> method, the degree of sewage stirring air without anaerobic microorganisms anaerobic sewage treatment tank into an inactive state supply An anaerobic sewage treatment method, comprising: 2. The anaerobic sewage treatment method according to claim 1, wherein the air is supplied intermittently. 3. The anaerobic sewage treatment method according to claim 2, wherein the amount of air when supplying air is 0.5 to 10 g / m ³ minutes in terms of oxygen. 4. allowed to flow into the water to be treated of domestic wastewater such as the one anaerobic sewage treatment tank, purifies sewage by anaerobic microorganisms in the one anaerobic sewage treatment tank, is precipitated deposited sludge
By causing, in the sewage treatment apparatus <br/> schemes make precipitate separating the treated wastewater and sludge, an air diffuser is disposed below the position of anaerobic sewage treatment tank, from dissipating degasifier An anaerobic sewage treatment apparatus characterized in that sewage stirring air is supplied to such an extent that anaerobic microorganisms are not inactivated. 5. The anaerobic sewage treatment apparatus according to claim 4, wherein the air is supplied intermittently. 6. The anaerobic sewage treatment apparatus according to claim 5, wherein the amount of air when supplying air is 0.5 to 10 g / m ³ minutes in terms of oxygen amount.