JPS61249598A - Two-phase type anaerobic treatment device - Google Patents

Abstract

PURPOSE:To prevent the clogging of separating membranes by sticking of contaminants thereto by providing an acid formation reactive part consisting of an acid forming bacteria- immobilized layer, separating membrane and supporting material and a methane formation reactive part consisting of a methane forming bacterial-immobilized layer, separating membrane and supporting material. CONSTITUTION:The acid formation reactive part 19 consists of the liquid permeable supporting material 21, the separating membrane 22 attached onto said material and the acid forming bacteria-immobilized layer 23 formed thereon. The methane formation reactive part 20 consists of the liquid permeable supporting material 24, the separating membrane 25 attached onto said material and the methane forming bacterial-immobilized layer 26 formed thereon. The acid formation reactive part and methane formation reactive part are contained in a tank body 14 and the feed water is passed through the separating membrane 22, the supporting material 21, the separating membrane 25 and the supporting material 24 in this order in the tank body 14 and is then taken out of the tank body. As a result, the clogging of the separating membranes by the sticking of the pollutants to the membranes is prevented and the smaller driving power for membrane permeation is required. The microorganisms are integrally immobilized on the separating membranes, by which the constitution of the device is made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a two-phase anaerobic treatment device, in which organic wastewater is first decomposed by acid-producing bacteria into organic acids such as acetic acid, which are then further decomposed into methane and other organic acids. This relates to a two-phase anaerobic treatment device that decomposes methane into methane using producing bacteria.

[Prior Art] As a method for anaerobically treating organic wastewater, there is a two-phase method that has higher treatment efficiency than a single-phase method. In this two-phase anaerobic treatment, anaerobic treatment is performed in two stages using different species of microorganisms, and the treatment conditions must be maintained to create the most favorable environment for each type of bacteria. processing efficiency is high.

By the way, in the anaerobic treatment method, it is known that the anaerobic treatment liquid is subjected to high-level treatment using membrane separation means such as an ultrafiltration membrane or a microfiltration membrane. The liquid is introduced into the membrane separation device, the concentrated liquid is returned to the anaerobic reaction tank, and the liquid passing through the membrane is taken out as treated water. In this way, it is possible to increase the sludge concentration in the anaerobic reaction tank, perform high-load treatment, and obtain highly treated water from which SS components and the like have been separated.

A combination of such anaerobic aeration and membrane separation treatment is also being considered in a two-phase anaerobic treatment system. FIG. 2 is a system diagram of a two-phase anaerobic treatment system that uses both the anaerobic treatment device and the membrane separation device.

In FIG. 2, raw water is introduced into an acid production reaction tank 2 from a pipe 1, and the treated liquid is extracted from a pipe 4 having a pump 3 and introduced into a membrane separation device 5. The liquid concentrated by the separation membrane 5a of the membrane separator 5 is returned to the acid production reaction tank 2 from the pipe 6, and the treated liquid that has passed through the separation 11!5a is sent from the pipe 7 to the methane production reaction tank 8. The reaction liquid in the methane production reaction tank 8 is extracted by a pipe 10 having a pump 9 and introduced into the membrane separation device 11, and the concentrated liquid is returned to the methane production reaction tank 8 by a pipe 12. is taken out from the pipe 13 as treated water.

According to the two-phase anaerobic treatment system that combines anaerobic treatment and membrane separation equipment as shown in Figure 2, high-load treatment is possible in each reaction tank 2.8, and the quality of the treated water is also highly improved. Become something.

[Problems to be solved by the invention] However, the two-phase anaerobic treatment method shown in Fig. 2 has a combination of an anaerobic reaction tank and a membrane separation device connected in two stages. Membrane separation equipment 5.1
In No. 1, membrane contaminants tend to adhere to the separation membranes 5a and lla, and the amount of liquid permeated through the membrane decreases in a relatively short period of time.
Chemical cleaning with chemicals and physical cleaning such as ball cleaning must be performed frequently, and the liquid permeation pressure of the S separation device must be increased to prevent a decrease in the amount of membrane permeate when membrane contaminants adhere. However, the power cost was also significant.

[Means for Solving the Problems] The present invention configures an anaerobic treatment reaction section by attaching a separation membrane in which microorganisms are immobilized on a support material through which a liquid can pass, and the anaerobic treatment reaction section are installed in two stages. The one installed at the front stage is an acid production reaction section in which acid-producing bacteria are used as microorganisms, and the one installed at the rear stage is a methane production reaction section in which methane production bacteria are immobilized. The stock solution first undergoes acid generation treatment in the acid generation reaction section, and then passes through the first separation membrane and the first separation membrane.
It passes through the support material and reaches the second separation membrane, where it is treated by the methanogens immobilized thereon. The liquid that has undergone this methane production reaction passes through the second separation membrane and the second support material and is taken out of the apparatus as treated water.

[Function] In the present invention, since microorganisms are immobilized on the separation membrane, membrane contaminants adhering to the membrane surface are quickly decomposed by the action of the immobilized microorganisms, and the phenomenon of membrane clogging is significantly suppressed. be done. Furthermore, since the separation membrane and the microorganisms are integrated, the overall structure of the device is compact and highly efficient processing is possible. Further, since membrane clogging is suppressed, only a small pressure is required to pass through the separation membrane, and therefore, it is possible to significantly reduce power costs.

Thermal theory is that the resulting treated water undergoes two stages of anaerobic treatment and two stages of membrane separation treatment, resulting in extremely high quality water.

[Example] Examples will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the configuration of a two-phase anaerobic treatment apparatus according to an embodiment of the present invention. Reference numeral 14 denotes a tank body of a reaction tank, which has an inlet 15 for raw water at the top and an outlet 16 for treated water at the bottom. Pipes 17 and 18 are connected to the inlet 15 and the outlet 16, respectively.

Inside the tank body 14, an acid production reaction section 19 and a methane production reaction section 20 are installed so as to cross the tank body 14.

The acid generation reaction section 19 has a support material (first support material) made of a material through which a liquid can pass, which is installed across the reaction tank 14.
21. It has a separation membrane 22 mounted on the support material 21 and an immobilized layer 23 of acid-producing bacteria formed on the surface of the separation membrane 22.

The methane production reaction section 20 includes the reaction tank 1 as well as the supporting material 21.
A support material (second support material) 24 made of a material through which a liquid can pass, which is installed across the support material 24, and a separation membrane 25 loaded on the support material 24, and a support material formed on the surface of the separation membrane 25. The structure includes a fixed layer 26 of methane-producing bacteria. The space between the acid production reaction section 19 and the inlet 15 is an acid production chamber 27, and the acid production reaction section 19 and the methane production reaction section 20
There is a methane generation chamber 28 between the two. Further, a treated water chamber 29 is located between the methane production reaction section 20 and the outlet 16.

In this embodiment, pipes 30 and 31 are connected to the tank body 14 in order to extract gas generated by the action of microorganisms from the acid generation chamber 27 and the methane generation chamber 28.

In the present invention, a porous material with good water permeability is preferably used for the supporting materials 21 and 24, and specifically, for example, sintered alloy, porous ceramic, unglazed earthenware, etc. can be used.

As the separation membrane used in the present invention, an ultrafiltration membrane or a precision filtration membrane is preferable.If the first separation membrane 22 is a separation membrane that can permeate lower fatty acids produced by the decomposition action of acid-producing bacteria, Accumulation of lower fatty acids in the acid-producing chamber 27 is avoided, making it possible to maintain the activity of the acid-producing bacteria at a high level.

Further, by using an ultrafiltration membrane with a molecular weight cut-off of about 2,000 to 20,000 as the second separation membrane 25 in which methanogenic bacteria are maintained, highly treated treated water can be obtained.

In the apparatus configured in this way, by flowing raw water under moderate pressure, the organic substances contained in the acid-producing bacteria are decomposed and the liquid is reduced to low molecular weight, and the liquid is transferred to the methane generation chamber 28.
The water flows into the water, undergoes efficient methanation treatment, and becomes highly treated water. In addition, the liquid can pass through the separation membrane without applying new power during the process, reducing power costs.

In the present invention, membrane contaminants adhering to the membrane surface are decomposed by the biological action of microorganisms immobilized on the separation membrane, so conventional chemical cleaning is not necessary.
Inorganic substances and organic substances that are difficult to biodegrade in the raw water adhere to the first separation membrane 22. In this case, ° methane generation chamber 28
These contaminants can be easily removed by supplying pressure water from the side through the first support material 21 to wash (backlight) the separation membrane 22.

The following method can be used to immobilize microorganisms on a separation membrane.

■ A method of immobilizing microorganisms on the surface of a separation membrane using a glue-like substance that allows water to pass through, such as acrylamide or polyvinyl alcohol.

■ A method in which porous fillers such as activated carbon, porous ceramics, and sponge-like polymeric substances are attached to the surface of a separation membrane, and microorganisms are allowed to adhere to and multiply on the surface or inside of these fillers.

■ A method of forming membranes so that the membrane and living organisms become one.

etc.

In the embodiment shown in FIG. 1, each support member 21.24 has a flat plate shape, but in the present invention, the support member 21.24 may have another shape, for example, a cylindrical shape. Also, although one reaction tank 14 is shown as one tank body, it may be divided into a tank having an acid production reaction section 19 and a tank having a methane production reaction section 20. In this case, both tanks have A chamber corresponding to the treated water chamber 29 in FIG. 1 is provided.

Next, a suitable experimental example will be explained.

Experimental Example 1 (Invention) In the apparatus shown in FIG.
Using a column with a stirring device with a height of 20 cm, support material 2
Unglazed pottery was used as 1.24. In addition, piping 30
and 18 were connected to a pipe 33 having a back pressure valve 32, and the operating pressure was adjusted by adjusting the valve pressure of this back pressure valve 32.

Further, a portion of the treated water taken out from the pipe 33 can be introduced into the acid generation chamber 27 through the pipe 34.

A level meter 35 for detecting the liquid level is installed in the acid generation chamber 27, and when the liquid level detected by the level meter 35 falls below a set value, the acid generation chamber 27 is The treated water was returned to the tank to maintain a constant level of liquid in the tank. Further, a stirrer 36 was provided in the acid generation chamber 27 to stir the liquid in the chamber.

Further, an ultrafiltration membrane 22.25 with a molecular weight cut off of 8000 was provided on the support material 21.24, and a sponge with an average pore diameter of 0.1 mm and a thickness of 10 mm was further placed thereon as a biological fixation material.

Acid-producing bacteria and methanogenic bacteria were attached to this sponge in the following manner. That is, acid-producing bacteria previously grown on a glucose substrate and methanogens grown on an acid substrate are each attached to a sponge using a 1% agar solution. The amount of attached bacterial cells was 1 g-VSS for each.

The liquid volume in the column is 11, and the column back pressure is 2 kg/crn'.
The liquid temperature was 30°C. Raw water is mainly composed of glucose,
C0Dc r10000mg/! Let's say L.

Water flow rate is 100-400m! L/day, load amount 1-4g-
It was set as CODcr/see/day. No pH adjustment was performed.

Load amount is 1.2.4g-CODcr/l/day, each t
Continuous operation was performed for o-15 days. C under each load condition
The 0Dcr removal rate and the amount of liquid permeated through the separation membrane 22.25 are shown in Table 1 below.

From Table 1, it is clear that even if the load amount is increased, good treatment can be performed in the examples of the present invention, and there is no decrease in the amount of liquid permeated through the separation membrane.

[Effects] As detailed above, the present invention prevents clogging due to adhesion of contaminants to the separation membrane, eliminates the need for chemical cleaning as in the conventional example, and eliminates inorganic and organic adhesion that is difficult to biodegrade. can be easily removed by simple backwashing.

In this way, since there is no clogging of the membrane, the power required for membrane permeation can be significantly reduced. Furthermore, since the microorganisms are integrally immobilized on one separation membrane, the device configuration becomes compact. Furthermore, the quality of the treated water is also extremely excellent.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a two-phase anaerobic treatment apparatus according to an embodiment of the present invention, and FIG. 2 is a system diagram showing the general configuration of a conventional two-phase anaerobic treatment apparatus. 14...tank body, 15... raw water inlet. 16... Treated water outlet, 21.24... Support material, 22.25... Separation membrane, 23... Acid-producing bacteria fixed layer, 26... Methanogen-producing bacteria fixed layer, 27. ...Acid generation chamber, 28...Methane generation chamber, 3
2...Back pressure valve. Agent Patent Attorney Tsuyoshi Shigeno Figure 1 Figure 2 1 2 655a7 6 1211 11a Procedural Amendment May 27, 1985

Claims (3)

[Claims] (1) Acid production reaction having a first support material through which a liquid can pass, and a first separation membrane on which acid-producing bacteria are immobilized and attached to one surface of the first support material. a second support material through which a liquid can pass; and a second support material on which methane-producing bacteria are immobilized and which is attached to one surface of the second support material.
a methane production reaction section having a separation membrane; a tank body that accommodates the acid production reaction section and the methane production reaction section;
A two-phase anaerobic treatment device characterized in that the device is taken out of the tank after passing through a second separation membrane and a second support material in that order. (2) The acid production reaction section and the methane production reaction section are arranged in one tank body having a liquid inlet at one end and a liquid outlet at the other end, respectively. An acid production chamber is formed between the liquid inlet and the acid production reaction section, and a methane production chamber is formed between the acid production reaction section and the methane production reaction section. A two-phase anaerobic treatment apparatus according to claim 1, characterized in that: (3) The two-phase anaerobic treatment apparatus according to claim 2, further comprising gas exhaust means from the acid generation chamber and gas exhaust means from the methane generation chamber.