JPS61249592A - Biological reaction device - Google Patents

Abstract

PURPOSE:To make the constitution over the entire part of a device compact by disposing separating membranes on liquid permeable supporting materials, depositing microorganisms on the surfaces of the separating membranes and installing the assembly into a reaction vessel. CONSTITUTION:The liquid permeable supporting materials 4 are disposed in a manner as to part an introducing port 2 and a take-out port 3 in the reaction vessel 1 provided with the introducing port 2 for the feed liquid and the take-out port 3 for the produced liquid in a biological reaction device for treating biologically org. waste liquid by using microorganisms. The separating membranes 5 are disposed on the surface on the feed liquid side of the materials 4 and further layers 6 to carry the microorganisms are provided on the surface on the feed liquid side of the membranes 5. Since the microorganisms are deposited on the separating membrane surfaces, the constitution over the entire part of the device is made compact. The clogging of the separating membranes is prevented by the effect of the microorganisms, by which the decrease in the rate of the liquid permeation through the membranes is lessened. The separating membranes do not require cleaning or require very little cleaning.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a biological reaction device, and particularly to a biological reaction device using a separation membrane such as an ultrafiltration membrane or a microfiltration membrane in which microorganisms are immobilized. The present invention relates to a biological reaction device designed to carry out such a reaction.

[Prior Art] A biological reaction device that combines a biological treatment device and a membrane separation device is known in the field of wastewater treatment devices, etc.
For example, Japanese Patent Publication No. 57-7293 discloses a system in which biological treatment liquid from a biological treatment device is subjected to membrane separation treatment and the concentrated liquid is returned to the biological treatment device.
No. 584 discloses a system in which treated water after biological treatment is subjected to membrane separation to improve the quality of the treated water.

As described above, the role of the membrane separation membrane in a biological reaction device equipped with a conventional membrane separation device is to maintain the sludge concentration in the biological treatment device above a predetermined value, remove SS from the biologically treated water,
It removes residual components that cannot be decomposed by biological treatment, and plays roles such as final sedimentation, coagulation and sedimentation, and filtration.

Even in such a conventional biological reaction device, it is possible to increase the concentration of microorganisms (for example, sludge concentration) in the biological treatment device, thereby providing a treatment device with a high load amount.

[Problems to be Solved by the Invention] However, the conventional biological reaction device described above is simply a combination of a biological treatment device and a membrane separation device, each of which has a different function, and there is a limit to its high efficiency. In addition, membrane contaminants from the biological treatment equipment (e.g. sludge, residual components, inorganic substances in the raw solution, metabolic substances of organisms, etc.) adhere to the separation membrane in conventional biological reaction equipment, reducing the amount of water permeated through the separation membrane. It was necessary to perform operations to remove substances adhering to the membrane surface, such as chemical cleaning and pole cleaning. Furthermore, in the above biological reaction device, a membrane cleaning device is also required in addition to the biological treatment device (reaction tank) and the separation membrane, and a unit having three different functions is required.

[Means for solving the problems] The present invention provides a separation membrane disposed on a liquid-permeable support material,
Microorganisms are supported on the surface of the separation membrane on the raw solution side, and this is placed in a reaction vessel. Then, the stock solution is introduced into a reaction vessel, subjected to biological treatment using microorganisms supported on a separation membrane, and then taken out from the reaction vessel by passing through the separation membrane and support material.

[Function] In the present invention, since microorganisms are supported on the separation membrane surface, unlike a conventional biological reaction device that simply combines a biological treatment device and a separation device, a biological treatment means and a membrane separation device are combined. can be incorporated into one unit, resulting in a highly efficient and compact processing device. Furthermore, since the substances adhering to the separation membrane are decomposed by the immobilized microorganisms, cleaning of the membrane is unnecessary or can be done very infrequently.

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

FIG. 1 is a longitudinal cross-sectional view of a bioreactor according to an embodiment of the present invention, and FIGS. 2 and 3 are the lines ■-■ and m-m in FIG.
A cross-sectional view along the line, FIG. 4 is a longitudinal cross-sectional view of a bioreactor according to a different embodiment.

Since FIG. 4 shows the most basic configuration of the present invention, the configuration of the present invention will first be explained with reference to FIG.

In FIG. 4, reference numeral 1 denotes a container of the reactor, and an inlet 2 for the stock solution is provided at the upper part, and an outlet 3 for the production solution is provided at the lower part. A support member 4 made of a liquid-permeable material is installed so as to cross the container 1 in the horizontal direction, thereby dividing the inside of the container 1 into a stock solution chamber 1a and a production solution chamber tb. A separation membrane 5 is provided on the liquid introduction side of the support material 4, and a layer 6 carrying microorganisms (bioimmobilization layer) 6 is provided on the surface of the separation membrane 5.

In the bioreactor configured in this way, the inlet 2
The stock solution introduced into the reaction vessel 1 is subjected to biological treatment by contacting the biological immobilization layer 6 and is biologically decomposed. The decomposition products pass through the separation membrane 5, pass through the support material 4, enter the product liquid extraction chamber 1b, and are then extracted from the extraction port 3.

In this way, the substance decomposed or modified by the microorganisms supported on the surface of the separation membrane 5 is immediately separated by the separation membrane. In addition, membrane surface clogging contaminants that adhere to the membrane surface and reduce the amount of permeated water are biologically decomposed by immobilized microorganisms. Therefore, processing efficiency is high, membrane clogging is suppressed, and the frequency of membrane cleaning treatment is extremely reduced.

Note that members 11-13 will be explained in the experimental example section.

Next, a preferred embodiment of the present invention will be described with reference to FIG.

In FIG. 1, the reaction vessel l has the stock solution inlet 2 at the top,
Further, a production liquid outlet 3 is provided at the bottom, and a partition plate 7 is provided inside the outlet. This partition plate 7 has a plurality of circular holes, and a cylindrical support member 4 is provided so as to rise from the holes toward the stock solution chamber la side. Then, molecules 11111! I5 is provided,
A biological immobilization layer 6 is provided on the surface of this separation membrane 5. Note that the upper end surfaces of the support material 4, separation membrane 5, and biological immobilization layer 6 are sealed with a lid-like member 8.

Also in the embodiment shown in FIG. 1, from the inlet 2 to the stock solution chamber 1.
The stock solution introduced into a is subjected to biological treatment (for example, decomposition, reforming reaction, etc.) by microorganisms immobilized in the biological immobilization layer 6. The generated substance passes through the separation membrane 5 and the support material 4, enters the production liquid chamber tb, and is taken out from the outlet 3. In the figure, lO is a gas outlet.

In the embodiment shown in FIG. 1, the surface area of the support material 4 provided in the reaction vessel 1 is larger than that in the embodiment shown in FIG.
The area of the microorganism immobilization layer 6 is also large, and therefore the amount of stock solution that can be treated with the same volume is extremely large.

In addition, in the present invention, as shown in FIGS. 1 and 4, a pipe 1c may be provided to return a part of the production liquid to the stock solution chamber la side, or, of course, an excessive amount may be allowed to flow down. .

In the present invention, as the support material 5, sintered alloy, porous ceramics, unglazed earthenware, etc. can be used.

Various types of separation membranes can be used without particular limitation, but it is preferable to select one according to the type of reaction. For example, when performing ordinary wastewater treatment, a membrane with a pore size of 1-0. IILm precision filtration membrane can be used, and when performing advanced wastewater treatment, the molecular weight cut-off is 20,000 to 1.
000 ultrafiltration membranes can be used. Further, when performing organic acid fermentation, alcohol fermentation, etc., a microfiltration membrane or an ultrafiltration membrane that allows the generated organic acid and alcohol to pass through can be used.

The microorganisms to be supported on the separation membrane surface are selected depending on the desired reaction; for example, when performing anaerobic wastewater treatment, acid-producing bacteria and methane-producing bacteria are used. In addition, when performing aerobic wastewater treatment, zooglare or the like is used. If the purpose is alcoholic fermentation, carry yeast. Therefore, the term "microorganism" in the present invention is used in a broad sense, including yeast and enzymes.

Note that when anaerobic bacteria such as acid-producing bacteria and methane-producing bacteria are immobilized and anaerobic biological treatment is performed, the stock solution chamber 1a is brought into an anaerobic state. In addition, when performing aerobic biological treatment by immobilizing aerobic microorganisms, an aeration device may be provided in the stock solution chamber 1a, or oxygen may be sufficiently dissolved in the stock solution in advance.
Introduce into a.

The following methods can be used to support microorganisms on the separation membrane surface.

■ Microorganisms are attached to the surface of the separation membrane using a water-permeable supplement such as acrylamide or carrageenan.

(2) A porous filler such as activated carbon or sponge is attached to the surface of the separation membrane using the above-mentioned auxiliary material such as acrylamide or carrageenan, and microorganisms are allowed to adhere and multiply on the surface and within the pores of this filler.

Therefore, in the present invention, as mentioned above, the membrane surface clogging contaminants that adhere to the membrane surface and reduce the amount of permeated water are biologically decomposed by the microorganisms supported on the separated membrane surface. Clogging of the separation membrane hardly progresses. However, if the device is operated for a long period of time, inorganic substances, persistent substances, biological metabolites, etc. in the stock solution may accumulate on the surface and voids of the separation membrane, causing clogging. could be. In that case.

Clean liquid or production liquid is supplied from the production liquid chamber 1b side through the support material 4 to backwash the separation membrane and peel off the clogging substances.

Next, a suitable experimental example will be explained.

Experimental example 1 (example of the present invention) In the apparatus shown in Fig. 4, one reaction vessel l has a diameter of 10 mm.
Using a column with a stirring device 11 with a height of 20 cm and a height of 20 cm,
Unglazed pottery was used as the support material 4. An ultrafiltration membrane 5 with a fractional separation amount of 8,000 was placed on top of this, and a 10 mm thick sponge was adhered thereon as a biological fixation material using 1% agar solution.

Anaerobic bacterial cells were attached to this sponge in the following manner. That is, 1 g of anaerobic bacterial cells grown using a synthetic substrate containing a mixture of glucose and acetic acid was concentrated as a vSS amount and put into a reaction vessel 1, and the bacterial cells were attached to a sponge using agar.

The agar concentration was 0.1% or less.

The experimental substrate was C mixed with glucose and acetic acid.
A synthetic substrate with ODcrlO000 mg/Jl was used.

This substrate was continuously pumped into the reaction vessel 1 for 10 minutes.
In addition to injecting at a rate of 0 mJL/day, a level meter is installed to detect the level in order to keep the liquid level in the reaction container l constant, and when the liquid level drops, a part of the production liquid is transferred to the stock liquid chamber 1a. Sent it back. Further, a pipe 13 having a back pressure valve 12 was connected to the raw liquid quality 1a and the production liquid chamber tb, and the operating pressure was set to 2 kg/crrf by adjusting the back pressure valve 12.

Note that the amount of liquid in the reaction container 1 was set to 1, and the pH of the liquid in the stock solution chamber 1a was adjusted using a phosphate buffer.

It was set as 6.8 to 7.2.

Table 1 shows the water quality of the produced liquid and the amount of liquid permeated through the ultrafiltration membrane 10, 20, and 30 days after the start of operation.

Experimental Example 2 (Comparative Example) Only an ultrafiltration membrane 5 having a molecular weight cutoff of 8000 was provided on the support material 4, and no biological immobilization layer 6 was provided thereon.

Then, instead of this biological immobilization layer, bacterial cells were suspended in the stock solution chamber 1, and an experiment was conducted in the same manner as in Experimental Example 1 above.

Table 1 shows the measurement results of the water quality of the produced liquid and the amount of permeation through the ultrafiltration membrane after 10, 20, and 30 days of operation.

In addition, in Table 1, the water quality of the production liquid is COD c from the raw liquid.
It is expressed as the removal rate of r.

Table 1 From Table 1, there is no difference in the water quality of the produced liquid between Experimental Examples 1 and 2, but the amount of liquid permeated in the invention example is more than double that of the comparative example, and the operation period is longer. It was observed that there was no decrease in the amount of liquid permeation.

[Effect] As detailed above, in the bioreactor of the present invention,
Since the microorganisms are supported on the surface of the separation membrane, the structure of the entire device becomes extremely compact.

Furthermore, the action of these microorganisms prevents clogging of the separation membrane, the decrease in the amount of liquid permeated through the membrane is extremely small, and cleaning of the separation membrane is not necessary or only needs to be done in a very small amount. Furthermore, unlike conventional separation membranes, there is no need for chemical cleaning.
Even when cleaning is required, simple backwashing is sufficient.

Furthermore, in the apparatus of the present invention, the production liquid is a liquid that has permeated through a separation membrane, so it is an extremely highly purified liquid that does not contain SS components. Furthermore, power for permeating the separation membrane may be unnecessary.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a biological reaction device according to an embodiment of the present invention, and FIGS. 2 and 3 are the lines ■-■ in FIG.
A sectional view taken along line -■, and FIG. 4 is a sectional view of a biological reaction device according to a different embodiment. 3... Reaction container, 2... Inlet, 3...
Output port, 4... Support material, 5... Separation membrane,
6... Biological immobilization layer, 7... Partition plate.

Claims (1)

[Claims] (1) A biological reaction device for biologically treating organic waste liquid etc. using microorganisms, which comprises a reaction vessel equipped with an inlet for a stock solution and an outlet for a production liquid, and the inlet and outlet. A liquid permeable support material arranged in the reaction vessel so as to separate them, a separation membrane arranged on the raw solution side surface of the support material, and a microorganism-supporting microorganism supported material provided on the raw solution side surface of the separation membrane. A biological reaction device comprising: