JPS596994A - Biological treatment of waste water containing organic substance - Google Patents

Abstract

PURPOSE:To efficiently biologically treat organic substance, by mixing residual anaerobic sludge-contg. waste water having passed thrugh an anaerobic tank with aerobic sludge discharged from the first aerobic tank, and then aerobically agitating the resulting newly formed sludge in the second aerobic tank. CONSTITUTION:Waste water is gathered in a conditioning tank 1, wherein making the properties of the liquid uniform, the addition of a nutritive source, etc. are performed at need, and then its predetermined amount is continuously supplied to an anaerobic tank 2. In the anaerobic tank 2, the waste water sent from the conditioning tank 1 is stopped and aerobically agitated by air fed therein from a blower 6. Since this aerobic agitation offers a very small amount of oxygen uniformly dissolved in the waste water for the propagation of facultative anaerobes living in the anaerobic tank 2 and the formation of anerobic sludge in which said facultative anaerobes are activated, an amount of aeration per unit for contaminating substance may be at a value below a tenth of that in the first aerobic tank 3.

Description

[Detailed Description of the Invention] This invention is based on the biology of wastewater containing organic substances such as fishery processing wastewater, raw wastewater stored by humans, and agricultural processing wastewater. Regarding J processing method.

As usual, there are no biological treatment methods for this type of wastewater. The activated sludge method, which consists of the steps shown in FIG. 1, has been used since J11FJ. In this method, wastewater is once stored in the adjustment tank A, and after being subjected to operations such as making the liquid uniform, adding nutrients, and adjusting the pH as necessary, a certain amount of wastewater is continuously pumped into the aeration tank B. While the wastewater remains in the aeration tank B for a certain period of time, the organic substances in the wastewater are oxidized and decomposed by aerobic bacteria that are active due to the air sent in from the blower C, resulting in activated sludge. (70 sludge is formed, and the wastewater is sent to the sedimentation separation tank DK together with this activated sludge.

In the sedimentation separation tank, the activated sludge and Doreki liquid are allowed to remain for a certain period of time to be separated, and the supernatant liquid is discharged as treated water. On the other hand, the settled activated sludge is transferred to the sludge pump E.
A part of it is returned to aeration tank B and used for circulation.
This maintains the activated sludge concentration within the tank to aid in oxidative decomposition by aerobic bacteria. The remaining activated sludge returned to the aeration tank B is removed from the circulation system as surplus sludge, and is separated into liquid and solid by a sludge dehydrator F, etc., and the solid is landfilled.
In this type of activated sludge method, when the BOD concentration of wastewater is high, oxidative decomposition by aerobic bacteria progresses rapidly. When treating with the sludge method, it is necessary to add a large amount of dilution water to lower the BOD concentration.

As the amount of wastewater due to this diluted water increases, the aeration tank B etc. becomes bulky and operation management becomes complicated. This is accompanied by various drawbacks such as an increase in the power cost of the blower C as the volume increases.

This invention was made in view of the above circumstances, and by treating wastewater efficiently regardless of the BOD concentration, operating costs can be reduced, equipment can be made smaller, and
The purpose is to simplify operation management, and its characteristics are that a part of the wastewater containing anaerobic sludge from the adjustment tank via the anaerobic tank and aerobic sludge returned from the sedimentation separation tank. The mixture is aerated and agitated in the first aerobic tank to form an aerobic sludge in which aerobic bacteria are exposed and anaerobic bacteria are latent. The new sludge produced by mixing the aerobic sludge from the first aerobic tank was aerated and stirred in the second aerobic tank (/'C), and aerobic bacteria became apparent again and anaerobic bacteria became latent. After converting into aerobic sludge, this aerobic sludge and wastewater are separated into a supernatant liquid and aerobic sludge in a sedimentation separation tank.
Biological treatment is performed in the wastewater treatment circulation system in which υF is discharged from the Nisumi liquid tobacco system and returned to the first aerobic tank for circulation as described in 11j.

The method of this invention will be explained in detail below with full reference to FIG.

In this invention method, wastewater containing organic substances is sent to a regulating tank 1 and an anaerobic tank 2, and the wastewater from the anaerobic tank 2 passes through the first aerobic tank 3 and the wastewater from the anaerobic tank 275. 2nd crowded
The aerobic sludge is sent to the aerobic tank 4 and the sedimentation-free separation tank 5, and the aerobic sludge separated in the sedimentation separation tank 5 is mixed with the wastewater from the anaerobic tank 2 and sent to the first aerobic tank 3. The wastewater is biologically treated in the wastewater treatment circulation system that returns it.

Among the bacteria that act in the wastewater treatment circulation system of this invention, the aerobic bacteria include the Zoogloea genus and other yeasts, and the anaerobic bacteria include oily anaerobic bacteria that have some aerobic properties. Bacteria, such as lactic acid bacteria (Lac
tobacillus), Petioconoccus (ped)
iococcus), Streptococcus (S t
reptococcus) genus, Bacillus (Bacillus)
Bacteria belonging to the genus Ius) are essential, and other lateral anaerobic bacteria may also be included.

When facultative anaerobic bacteria contain bacteria belonging to the genus Acidobacteria, specific effects described below are produced. These aerobic bacteria and anaerobic bacteria are previously introduced into the thread at the start of operation 11j of the wastewater treatment circulation system (!-), so that the bacteria that naturally proliferate in the system will be used thereafter.

Wastewater includes seafood processing wastewater, stocked raw wastewater, agricultural processing wastewater,
Any kind of wastewater containing other organic substances can be treated by the method of this invention.

This wastewater is first collected in a regulating tank, where the required V
Depending on C, work such as equalizing the liquid, adding nutrients, and adjusting the PH:A section is performed. Then, after staying for a predetermined time,
A fixed amount of water is continuously supplied to the anaerobic tank 2.

In the anaerobic tank 2, wastewater sent from the adjustment tank 1 is retained and aerated and agitated by air sent from the blower 6. This aeration agitation proliferates the oil-based anaerobic bacteria living in the anaerobic tank 2, and evenly provides a small amount of dissolved oxygen in the wastewater in order to generate anaerobic sludge in which the anaerobic bacteria are exposed. Therefore, the amount of aeration per unit pollutant is usually one-tenth or less of the amount of aeration in the first aerobic tank 3, which is based on experience and experimental VC,+
This is because if aeration is carried out in an amount greater than the amount specified in 1J, although the wastewater will be sufficiently agitated, facultative anaerobic bacteria will become inactive and anaerobic sludge will no longer be produced.

In addition, the adjustment tank 1 and the anaerobic tank 2 are divided into one Q and one, depending on the nature of the wastewater or various circumstances.
These two tanks 1.2 can also be made into regulating anaerobic tanks, but this is within the technical scope of the method of the present invention.

Aerobic bacteria that is returned from the sedimentation separation tank 5 in part of the wastewater containing anaerobic sludge in which anaerobic bacteria including facultative anaerobic bacteria generated by performing aeration that meets the conditions described above have become apparent. The anaerobic bacteria become apparent and mix with the latent aerobic sludge to generate new sludge, which is then introduced into the first aerobic tank 3 together with wastewater. The mixing ratio of the two is such that the solids concentration is equal or a little more aerobic sludge is mixed. These two different types of sludge have contradictory physical and chemical properties! Among these conflicting physicochemical properties, there is an increase in the affinity between aerobic and anaerobic sludge due to Koulonka and van der Waals forces, and a certain type of polymer bond between the two sludges. Competitive effects such as reaction formation and adhesion by mucous membranes formed by aerobic bacteria result in strong cohesive forces between the two sludges. Due to this strong cohesive force and the uptake of dissolved components as coagulation progresses, new sludge containing both aerobic and anaerobic bacteria is generated, and the purification effect of wastewater is promoted. By the way, aerobic sludge and anaerobic sludge produced from wastewater consisting of the same or similar pollutant components either have a strong cohesive force as described above, or, on the contrary, are produced from different wastewater. It has been experimentally found that there is no cohesive force between aerobic sludge and anaerobic sludge. This indicates that the aggregation reaction is not simply due to Coulomb force or van der Waals force, but also the existence of a certain kind of inter-polymer bonding reaction.

The newly generated sludge is transferred to the first aerobic tank 3.
By aeration and agitation, aerobic bacteria become apparent and anaerobic bacteria become latent aerobic sludge, which is then discharged from the first aerobic tank 3 together with the wastewater, and the facultative anaerobic bacteria in the anaerobic tank 2 are The anaerobic bacteria containing the anaerobic bacteria are mixed with the manifested anaerobic sludge and are generated for the same reason as described above, and are charged into the second aerobic tank 4-\ together with the sludge. The mixing ratio of these two is equal to the solids concentration, and the aerobic sludge is slightly more than the sludge.
Promotes the purification effect of wastewater containing This fresh sludge is in a state where both aerobic fraction and anaerobic bacteria are evident, but as it is aerated and stirred in the second aerobic tank 4, aerobic bacteria become apparent and anaerobic bacteria become apparent. 41] The straw becomes latent aerobic sludge and is sent to the sedimentation separation tank 5.

Second Sedimentation 5-J- In ship type 5, the aerobic sludge settles and the sludge is separated into seven separate layers. i is discharged as treated water to the outside of this wastewater treatment circulation system, and the aerobic sludge is mixed with a portion of the wastewater containing anaerobic sludge discharged from the anaerobic tank 2 by the sludge pot 7 as described above, and then transferred to the first aerobic tank. 0 The remaining aerobic sludge that is not returned is separated into solid and liquid by the sludge dehydrator 8 and discharged outside the wastewater treatment circulation system. Aerobic bacteria, including Zoogloea bacteria, which were previously introduced into various systems or have subsequently grown naturally, have become apparent, and anaerobic bacteria, including oily anaerobic bacteria, have become latent. Also, similar to the anaerobic tank 2, the first aerobic tank 3 and the second
Aeration and agitation in the aerobic tank 4 is also carried out by air sent from the blower 40, but it is of course possible to use other means for aeration and agitation in place of this.

Furthermore, in the anaerobic tank 2, anaerobic bacteria including facultative anaerobic bacteria that were introduced before the start of operation continue to proliferate due to aeration and agitation despite the inflow and outflow of wastewater, producing anaerobic sludge. B can be a wastewater treatment circulation system that also returns the wastewater to the air tank 1i'1 when the pollution concentration of the wastewater decreases due to various reasons. This is because, in the case of this system, anaerobic bacteria latent in the aerobic sludge can be exposed and proliferated by the aeration and stirring described above in the anaerobic tank 2. Therefore, in this system, the wastewater leaving the anaerobic tank 2 does not contain anaerobic sludge in which anaerobic bacteria have become apparent and aerobic bacteria have become latent, but the wastewater containing this anaerobic sludge and the sedimentation Similar to the system described above, the aerobic sludge returned from the separation tank 5, in which aerobic bacteria have become apparent and anaerobic bacteria have become latent, is mixed to produce sludge.

In the two wastewater treatment circulation systems, when lactic acid bacteria rather than oily anaerobic bacteria are included, the action of the lactic acid bacteria will further increase the strong sludge flocculation effect, and at the same time, the anaerobic sludge According to the theory F above, the production of anaerobic internal strife in the anaerobic tank 2 is promoted, and the progress of the state of putrefaction due to the proliferation of putrefactive bacteria in the anaerobic tank 2 is delayed, and therefore the generation of putrid odor is also prevented. As is clear from the town, this method is used to extract part of the wastewater containing anaerobic sludge, in which anaerobic bacteria including facultative anaerobic bacteria have become apparent, and zooglaia (Zooglaia).
a) The first purification treatment of wastewater is performed by mixing aerobic sludge in which aerobic bacteria including bacteria of the genus have become apparent and anaerobic bacteria have become latent to generate new sludge, and then the anaerobic bacteria The residual wastewater containing sludge and the new sludge of 11f1 were generated by aeration and agitation (Zooglare).
Wastewater purification treatment is also carried out by mixing wastewater containing aerobic sludge in which aerobic bacteria, including those of the genus Zoogloea), have become apparent and anaerobic bacteria have become latent, thereby generating all new sludge. Therefore, compared to the conventional activated sludge method, even when the concentration of raw wastewater is high, it is necessary to dilute it. Management can be simplified. Furthermore, since a small amount of aeration is required, the cost required for operation and management is also reduced.

Examples of this invention will be described below.

Wastewater General process wastewater generated during the processing of mackerel and sardines, boiling liquid, and liquid removed from methane fermentation.

General process wastewater BOD concentration 6,0011 ppm, 4
50 t/day broth, BOD concentration 50,000pp
m, 10 t/['' De-i when methane fermentation is carried out in a straight needle! If liquid -BODa degree 12.000ppm,,l
The BOD concentration of this wastewater (total 470t/B) is (450t/day).
0t/IEx6Kg +10t/l Go IX 5Kg+
10t/l 1X 1.2kg) ÷470[/day=7,
064ppm.

Aeration amount in conventional activated sludge method Amount of air required to treat BOD concentration IKg 50m
3//As BODKg, 470 days x 7.06Kg x 50nT3 ÷ 24 hours ÷ 60 minutes = 115.3-minutes The blower required for this aeration amount is 30KW x 5 units. 4,701/day of wastewater is sent to the first aerobic tank.
50t/Method 82 320t/E1 distributed to the aerobic tank 0 Sludge return is 450t/day 0 Also, the BOD concentration at the inlet of the second aerobic tank is 750 ppm, 92
Aeration air volume in 0t/B anaerobic tank = 470 [/day 75Kg x 50 m3÷2
4 hours ÷ 60 minutes = 240 m'z minutes The aeration air volume of the 1st aerobic tank is the same as that of the 2nd aerobic tank. Total aeration volume - 11.4 rJ'm +
24.0m x 2 = 46.8+J'min The blowers required for this aeration are 2 x 30KW.

As is clear from the above examples, the amount of aeration by the method of this invention is less than half that of the conventional activated sludge method.

In addition, in the conventional activated sludge method, wastewater under the above conditions cannot be treated at 1x, so it must be diluted to 2 to 3 times. For this purpose, installation of dilution water supply equipment,
There are various drawbacks such as the cost of dilution water, the increase in the size of each device due to the increase in waste water, and the complexity of operation and management, but the method of this invention can eliminate all of these drawbacks.

[Brief explanation of the drawing]

Each is shown below. l-・Adjustment tank, 2 anaerobic tank, 3・1st aerobic tank, 4・2nd
Aerobic tank, 5. Sedimentation separation tank.

Claims (1)

[Claims] 1. Sending the wastewater containing organic substances from the adjustment tank to the anaerobic tank, and mixing the wastewater from the anaerobic tank via the first aerobic tank with the wastewater from the anaerobic tank described in item 11. The wastewater treatment circulation system sequentially sends the sludge to a second aerobic tank and a sedimentation separation tank, and mixes the aerobic sludge separated in the sedimentation separation tank with wastewater from the anaerobic tank and returns it to the first aerobic tank. Therefore, in the anaerobic tank, aeration and agitation suitable for producing anaerobic sludge in which anaerobic bacteria including facultative anaerobic bacteria are exposed is performed, and a part of the wastewater containing this anaerobic sludge is Preferably, the sediment contains bacteria of the genus Zoogloea, which is returned from the sediment;
Mix aerobic sludge in which aerobic bacteria have become apparent and anaerobic bacteria have become latent to produce sludge, and aerate and stir it in the first aerobic tank! -The aerobic sludge basin in which aerobic bacteria became apparent and anaerobic bacteria became latent, and the wastewater containing this new aerobic sludge! : The remaining wastewater containing the anaerobic sludge was mixed to generate sludge, and aerobic agitation was performed in the second aerobic tank, whereby aerobic bacteria became apparent again and aerobic sludge with latent anaerobic bacteria was generated. After that, the wastewater containing this aerobic sludge was sent to the tank 4a, and the aerobic sludge separated by seven excreta was returned to the first aerobic tank as described above. A biological treatment method for wastewater containing organic substances, characterized in that the remaining aerobic sludge and the supernatant liquid are discharged outside the wastewater treatment circulation system. 2. The method for biological treatment of wastewater containing organic substances according to claim 1, wherein the facultative anaerobic bacteria are facultative bacteria including bacteria of the genus Lactobacillus. 3 Send the wastewater containing organic substances from the adjustment tank to the anaerobic tank, and from the anaerobic tank, mix the wastewater that has passed through the first aerobic tank with the wastewater from the anaerobic tank and send it to the second aerobic tank for sedimentation separation. A wastewater treatment circulation system in which the aerobic sludge separated in the sedimentation separation tank is mixed with wastewater from the anaerobic tank and the anaerobic tank and returned to the first aerobic tank, In the tank, the anaerobic sludge in which facultative anaerobic bacteria have become apparent is subjected to aeration and agitation suitable for increasing the amount of anaerobic sludge, and a part of the wastewater containing this anaerobic sludge and the sedimentation are mixed. Zoogloea (Zoogloea) returned to the separation tank
Mix aerobic sludge in which aerobic bacteria including 14-bacteriologists have become apparent and anaerobic bacteria have become latent (by generating sludge in - and aerating and stirring in the first aerobic tank, aerobic bacteria become apparent and anaerobic bacteria The remaining aerobic sludge containing this new aerobic sludge is mixed with the remaining wastewater containing the anaerobic sludge to produce sludge, which is then aerated and agitated in a second aerobic tank. After re-generating aerobic sludge in which aerobic bacteria are exposed and anaerobic bacteria are latent, the wastewater containing this aerobic sludge is sent to a sedimentation separation tank, and the aerobic sludge separated from the clear liquid is The remaining aerobic sludge returned to the first aerobic tank and the anaerobic tank, and the remaining aerobic sludge returned to the first aerobic tank and anaerobic tank as well as 1111-1: Clear liquid wastewater treatment circulation system. 4. A biological treatment method for wastewater containing an M@ substance, characterized in that the organic anaerobic bacteria according to claim 3, wherein the facultative anaerobic bacteria are facultative bacteria including bacteria of the genus Lactobacillus. Biological treatment method for wastewater containing pollutants.