JP3118220B2 - Organic wastewater biological treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological treatment method for organic wastewater, and more particularly to a biological treatment method suitable for purifying organic wastewater such as agricultural settlement wastewater containing domestic wastewater and human waste.

[0002]

2. Description of the Related Art Conventionally, in the treatment of organic sewage such as sewage, the emission of offensive odors contained in the organic sewage itself,
In addition, the sludge generated in the treatment system caused anaerobic decomposition while staying, resulting in generation of offensive odor, and the odor generated in each tank was considerably strong, leading to deterioration of the working environment. Therefore, various techniques have been developed to prevent and deodorize odors from sewage and sludge in a liquid state while treating organic sewage such as sewage, as a countermeasure against odors. ) Are known. In this prior art, organic sewage is mixed with sludge in a pretreatment step, and then the sewage is treated with anaerobic microorganisms in an anaerobic filter tank, and then treated with aerobic microorganisms in an aerobic filter tank. After returning part of the treated water of the aerobic filter tank to the anaerobic filter tank to suppress the odor in the anaerobic filter tank, and also conducting other treated water to the settling tank to settle the sludge Disinfect and release.

[0003] The sludge generated in the anaerobic filter tank or the sedimentation tank is led to a concentrated sludge storage tank to be concentrated, and the sludge is circulated between the concentrated sludge storage tank and the reactor, and the sludge is humified in the reactor. The sludge is contacted with the porous pellets to perform an aeration process to perform an oxidation reaction and the growth of microorganisms, and the sludge is returned from the concentrated sludge storage tank to the pretreatment step as circulating sludge. However, in the above-described conventional technology, anaerobic decomposition accompanying sludge retention and the like in anaerobic biofilm treatment tends to occur and anaerobic sludge tends to be generated in large quantities, and the problem that odor control is insufficient, In addition, the sludge generated in the anaerobic filter bed (first-stage sludge) and the sludge generated in the sedimentation tank (second-stage sludge) are not always introduced into the concentrated sludge storage tank at a constant ratio. Sludge tends to be unevenly distributed in the concentrated sludge storage tank, and there is a problem that a malodor is generated due to a fluctuation or uneven distribution of the ratio between the whole-stage sludge and the second-stage sludge.

That is, the ratio of the former sludge and the latter sludge is usually large because the absolute amount of the former sludge generated is large, so that the aerobic biological reaction is slowed down. Was difficult. In particular, when the ratio of each sludge in the concentrated sludge storage tank fluctuates, or when the sludge is unevenly distributed, the load on the reactor also fluctuates greatly, and bad odor is caused by insufficient treatment such as oxidation. In some cases, the generated sludge, which has not been sufficiently treated by oxidation or the like, is returned to the pretreatment step, thereby causing an odor in the pretreatment step. In order to solve these problems, the present inventors have previously proposed Japanese Patent Application Nos. 9-369452 and 9-369453. However, these techniques do not refer to a method of transferring the returned separated liquid and / or sludge. Conventionally, the separated liquid and / or sludge is returned in a fixed amount with respect to a total amount in a day or a fixed period during a day or a fixed period. According to this method, when the inflow amount fluctuates during the period, when the inflow amount is large, the return amount is insufficient, causing odor.

[0005]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a biological treatment method for organic wastewater which can always prevent the generation of odor even when the amount of wastewater inflow varies. I do.

[0006]

In order to solve the above problems, according to the present invention, an organic wastewater is biologically treated in a biological treatment step after being received in a biological treatment pretreatment step, and is generated in the biological treatment step. The sludge is introduced into the sludge treatment step, treated with a filler containing humus, and the separated liquid and / or sludge containing the humus is returned to the organic wastewater pretreatment step. in the processing method, the biological treatment is given for the inflow of wastewater that flows into the pretreatment step ratio
In is performed by adjusting the return quantity of separated liquid and / or sludge containing the humus, regulation of the return amount performed by the constant ratio, flows
Measure the hourly accumulated amount of the flow meter and proportionally
The pump for returning the separated liquid and / or sludge for one hour thereafter
This is to control the operation time .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The organic sewage suitable for the present invention is, for example, agricultural settlement effluent including household wastewater and human waste, but is not limited thereto, and the treatment method of the present invention is preferably applied to all organic sewage having an odor in the influent water. Can be applied. The biological treatment step of the present invention may be any of anaerobic treatment and aerobic treatment, and any treatment method for biologically treating sewage and discharging sludge can be used, particularly under anaerobic conditions. Biological treatment, and then biological treatment under aerobic conditions, and a biological treatment method in which the treatment liquid is partially circulated to an anaerobic treatment step for treatment, and sewage is aerated, stirred, settled, and discharged in multiple batch tanks And a batch-type biological treatment method that repeats the above.

[0008] In the sludge treatment step, sludge generated by the biological treatment step, for example, sludge generated by anaerobic treatment and aerobic treatment, is separated into sludge. The filler containing humus to be brought into contact with sludge is a humus having a dominant bacterium including bacillus and actinomycete such as humus as a seed bacterium, and a mixture of a magnesium compound, cellulose and chitin. Has been filed by the present inventors (Japanese Patent Application No. 9-369454). The contact between the sludge and the filler is preferably performed by aerobic biological treatment while diffusing. Next, the sludge treated as described above is returned as it is or after solid-liquid separation, and the separated liquid is returned to the pretreatment step. This return amount is measured at a fixed ratio to the inflow of sewage received in the pretreatment process.Specifically, the inflow of sewage flowing into the pretreatment process is measured by an inflow flow meter, and measured by a ratio setting device. The rotation speed of the return pump can be controlled so that the return amount of the separated liquid and / or the sludge matches the inflow amount of the wastewater. Alternatively, the operation can be performed by integrating the inflow amount of the wastewater every hour, and controlling the operation time of the return pump for the separated liquid and / or sludge for one hour thereafter in proportion to the amount.

Next, the present invention will be specifically described with reference to the drawings. FIG. 1 is a flowchart illustrating the processing method of the present invention. In FIG. 1, W indicates a sewage treatment system, C indicates a sludge treatment system, and the sewage treatment system W includes a pretreatment step 1, a flow control tank 2, an anaerobic filter tank 3, a contact aeration tank 4, a sedimentation tank 5, It has a disinfection tank 9, and the sludge treatment system C includes a sludge receiving tank 6, a sludge circulation tank 7, a sludge contact tank 8, a separation liquid tank 10, and a sludge concentration tank 1.
1 and a sludge storage tank 12, 13 is a sewage flow meter, 14
Denotes a ratio setting device, and 15 denotes a return pump. Organic sewage 1
6 is introduced into the pretreatment step while measuring the inflow amount by the sewage flow meter 13, and the separation liquid and / or sludge 21 described later
After being subjected to pretreatment such as removal of coarse substances, removal of sand and the like, and aeration, the mixture is introduced into the flow control tank 2.

From the flow control tank 2, a certain amount of sewage flows into an anaerobic filter tank 3 for biofilm treatment under anaerobic conditions, and is mixed with treated water 20 returned from a contact aeration tank 4 at a later stage. , Is partially denitrified, flows into the contact aeration tank 4, and is aerobically biologically treated. Part of the treated water in the contact aeration tank 4 is 20
Is returned to the anaerobic filter tank 3 and the remainder is introduced into the sedimentation tank 5. The treated water separated in the sedimentation tank 5 is disinfected in the disinfection tank 9 and discharged 17. On the other hand, the sludge 19 settled in the settling tank 5 is introduced into the sludge receiving tank 6 together with the sludge 18 withdrawn from the anaerobic filter bed tank 3. The sludge introduced into the sludge receiving tank 6 is sent out to a sludge circulating tank 7, and the sludge is circulated between the sludge circulating tank 7 and the sludge contact tank 8, and is brought into contact with the filler containing humus in the sludge contact tank 8. A part of the sludge in the sludge circulation tank 7 flows out to the separation liquid tank 10, and the other part is introduced into the sludge concentration tank 11 to concentrate the sludge, and then stored in the sludge storage tank 12.

The sludge that has flowed into the separation liquid tank 10 separates the sludge by sedimentation and separation and contains a humic substance as a supernatant, or
It is returned 21 to the pretreatment step 1 as it is without separation or together with the separated sludge. The return 21 to the pre-processing step 1
The inflow amount of the sewage is measured by the inflow meter 13, and the ratio setting device returns the separated liquid and / or sludge in an amount proportional to the inflow amount by controlling the rotation speed of the return pump 15. Alternatively, the inflow of sewage is integrated every hour, and the operating time of the return pump for separating liquid and / or sludge for one hour thereafter is controlled and returned in proportion to the amount.

FIG. 2 shows another flow diagram of the processing method of the present invention. In FIG. 2, the difference from FIG. 1 lies only in the sewage treatment system W, and there is no difference in the return of the sludge treatment system C and the separated liquid and / or sludge. In FIG. 2, the sewage treatment system W
Biological treatment process is performed in batch tanks 22a and 22b,
The introduction of sewage from the flow control tank 2 to the batch tank is performed in time series to the plurality of batch tanks 22a and 22b, and the batch tanks 22a and 22b are
Sludges 23a and 23b separated from 2b are respectively introduced into sludge receiving tank 6, and sludge treatment is performed in the same manner as in FIG. on the other hand,
The supernatant water in the batch tank flows into the watering pump tank 24 as treated water, and then is introduced into the disinfecting tank 9 where it is discharged 17 after disinfection. The batch tank can be used in only one tank.
2b and 23b become unnecessary.

[0013]

According to the present invention, the return amount of the separation liquid containing humus and / or the sludge can be adjusted in response to fluctuations in the inflow of sewage, and the generation of odor in the pretreatment step is always stably prevented. can do.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an example of a processing method according to the present invention.

FIG. 2 is a flowchart showing another example of the processing method of the present invention.

[Explanation of symbols]

1: Pretreatment step, 2: Anaerobic filter bed tank, 3: Contact aeration tank,
4: sedimentation tank, 5: disinfection tank, 6: sludge receiving tank, 7: sludge circulation tank, 8: sludge contact tank, 9: disinfection tank, 10: separation liquid tank, 1
1: Sludge concentration tank, 12: Sludge storage tank, 13: Sewage flow meter, 14: Ratio setter, 15: Return pump, 16: Sewage, 17: Treated water, 22a, 22b: Batch tank, 24: Sprinkling pump tank , C: Sludge treatment system W: Sewage treatment system

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiro Shinoka 1-10-14 Hamamatsucho, Minato-ku, Tokyo Within the Japan Agricultural Village Drainage Association (72) Inventor Takayuki Kada 11th Asahimachi Haneda, Ota-ku, Tokyo No. 1 Inside EBARA CORPORATION (72) Inventor Akira Ichihara 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside EBARA CORPORATION (56) References JP 5-31490 (JP, A) JP JP-A-63-97296 (JP, A) JP-A-2-245294 (JP, A) JP-A-56-136699 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 3 / 12

Claims (1)

(57) [Claims] Claims 1. Organic wastewater is received in a biological treatment pretreatment step (hereinafter referred to as a pretreatment step), and then biologically treated in the biological treatment step. Sludge generated in the biological treatment step is introduced into the sludge treatment step. In a biological treatment method, which is treated by contacting with a filler containing humus, and the obtained separation solution and / or sludge containing humus is returned to the pretreatment step of the organic wastewater.
The biological treatment is, in a constant ratio for the inflow of wastewater that flows into the pretreatment step, the separated liquid containing the humus and /
Or performed by adjusting the return quantity of sludge, return performed by said constant ratio
To adjust the flow rate, measure the integrated amount of the inflow flow meter every hour
And in proportion thereto the separated liquid for the next hour and / or
A biological treatment method for organic wastewater, wherein the operation time of a sludge return pump is controlled .