JP2000051878A - Method and apparatus for treating liquid with use of microorganism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable prompt restoration to normal treatment after a trouble such as the extinction of bacteria in a treatment tank by providing a process in which part of a liquid in the treatment tank containing microorganisms is preserved continually and temporarily. SOLUTION: An apparatus is equipped with a storage tank 3 for preserving part of a solution or treated water in a treatment tank 1 continually and temporarily outside the tank 1 and in other places. The treated water is introduced once in the storage tank 3 within a given time by using a timer 6 and others, and the solution which has been stored in the storage tank 3 is discharged into the treatment tank 1 or a treatment tank outflow line 5. When the damage of bacteria caused by abnormal treatment is detected there, temporary storage in the storage tank 3 and a discharge operation are stopped, bacteria of a normal time held in the storage tank 3 is stocked, and an operation to restore the treatment tank 1 to a normal state is done during the time. After that, the bacteria in the storage tank 3 are introduced into the treatment tank 1 to start up again to enable the prompt restoration of the apparatus in a normal state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid processing method and apparatus using microorganisms for continuously processing liquid such as water by utilizing microorganisms such as wastewater treatment and microorganism culture.

[0002]

2. Description of the Related Art In wastewater treatment such as the activated sludge method, and in microbial culture such as fermentation, the operation is carried out using microorganisms. I couldn't.

[0003] In order to prevent the germs from being killed, most of the devices utilizing microorganisms employ control methods such as temperature, pH and DO to control the growth conditions, and usually the germs are killed. Such situations are rare.

However, in practice, it is rare that bacteria in the processing tank are killed or almost killed due to equipment troubles or unexpected situations. In this case, for example, in activated sludge treatment, a method of receiving seed sludge from an activated sludge tank performed at another place and restarting it is adopted, and in the fermentation field, an agar medium preserved by passing over or a cryopreserved bacteria A method of starting small-scale cultivation from the body and (freeze-dried) preserved cells, gradually increasing the scale, and restarting as the inoculum of the present apparatus is adopted. In addition, when performing microbial treatment in multiple stages or when there is a sedimentation tank in the subsequent stage, only when the time to trouble detection is short,
It is possible to obtain the cells from the subsequent treatment tank or sedimentation tank, which is not affected by the trouble, and normalize the previous treatment tank before introducing them. If the growing condition worsened, the above method had to be followed.

[0005] Restarting a device utilizing microorganisms often requires time for securing inoculum, culturing at startup, and the like.
It is not uncommon for it to take several days. When operating microorganism utilization equipment industrially, the loss for several days is large, and in the case of wastewater treatment, untreated wastewater may flow out during that time,
Some measures were desired.

[0006]

Conventionally, in a liquid processing apparatus using microorganisms, when the microbial cells used in the apparatus are damaged or die due to a trouble or the like, the state of normal processing is promptly increased. There was a problem that it was not possible to return to normal processing or it took a long time to return to normal processing. An object of the present invention is to solve such a problem and to promptly return to a normal processing state after a trouble.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the above-mentioned problems have been solved by a method for continuously treating a liquid using microorganisms in a solution in a treatment tank containing microorganisms. It has been found that the method can be basically achieved by a microorganism-based treatment method characterized by having a step of intermittently temporarily storing part of treated water.

That is, the present invention provides: (1) a method for treating a liquid containing microorganisms, the method comprising a step of intermittently temporarily storing a part of the liquid in a treatment tank containing the microorganisms. Liquid treatment method.

(2) The temporary storage capacity is 0.1 to 10% of the processing tank.
The liquid treatment method using microorganisms according to the above.

[0010] (3) The method of treating liquid using microorganisms according to (1) or (2), wherein the interval of the step of storing intermittently is 5 hours to 3 days.

(4) The microorganism according to any one of (1) to (3), wherein the treatment liquid is a wastewater mainly composed of wastewater subjected to a weight reduction treatment of polyester fabric with sodium hydroxide. Use liquid treatment method.

(5) In a liquid processing apparatus utilizing microorganisms having a processing tank having microorganisms having at least a liquid inlet and a processing liquid outlet, a part of the liquid in the processing tank containing microorganisms is intermittently and temporarily removed. A liquid processing apparatus utilizing microorganisms, comprising a storage means.

(6) The liquid processing apparatus utilizing microorganisms according to the above (5), wherein the capacity of the temporary storage means is 0.1 to 10% of the processing tank.

(7) The liquid processing apparatus utilizing microorganisms according to the above (6) or (7), further comprising means for setting the intermittent preservation cycle from 5 hours to 3 days.

[0015] is provided.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be specifically described below. The method of treating liquid using microorganisms according to the present invention is characterized by including a step of intermittently temporarily storing a part of the liquid in the treatment tank containing the cells.

The liquid treatment method using microorganisms of the present invention is applied to all liquid treatment methods utilizing microorganisms, such as wastewater treatment including the activated sludge method and fermentation including amino acid production. In addition, the present invention is applied to continuous processing instead of batch processing, and includes intermittent intermittent processing at short intervals that can be regarded as substantially continuous.

Hereinafter, the method for treating liquid using microorganisms of the present invention will be described with reference to the drawings.

FIG. 1 is a flow chart showing an example of the liquid processing apparatus using microorganisms of the present invention, and FIG. 2 is a flow chart showing another example of the liquid processing apparatus using microorganisms of the present invention.

According to the present invention, the treatment tank 1 is provided outside or inside.
It is provided with a storage tank 3 for temporarily storing a part of the solution in the processing tank or the processing water intermittently. In FIG. 1, a raw material or treated water inflow line 4 and a treated water outflow line 5 are connected to a treatment tank 1. 2 is a stirrer. FIG.
In the example of (1), a storage tank 3 is provided outside, processing water is sent into the storage tank 3 once at a certain time by using a timer 6 or the like, and the solution in the storage tank 3 up to that time is placed in the processing tank 1 or the processing tank outflow line 5. Can be achieved by a method of discharging water.

In the example of FIG. 2, a part of the inside of the processing tank 1 is partitioned to form a storage tank 3, and treated water is sent into the storage tank 3 once at a certain time, and then enters the storage tank 3. It is also possible to adopt a method of discharging the used liquid into the processing tank 1 or the processing tank outflow line 5. In this example, processing is performed using an aerobic microorganism, oxygen is supplied through a diffuser 7, and an amount set at a time set by a timer 6 and an air lift 8 is sent to the storage tank 3.

The treatment tank 1 is usually equipped with measuring devices such as temperature, pH, dissolved oxygen concentration meter, ORP and the like, and the operating conditions are often controlled by the measured values. Due to some kind of abnormality, or an abnormality in the charged raw material, the treatment becomes suddenly or gradually abnormal, and in some cases, the cells in the treatment tank may be killed.

Conventionally, the cells are transferred from a similar device that is operating elsewhere, and then re-started, or the preserved cells, which have been frozen and stored, are gradually cultured from a small scale to a large scale. It is a method of inoculum and the method of restarting the equipment, it takes a long time to secure and restart the bacteria for restarting, and if it is used industrially, the damage during that time can be ignored Did not.

In the present invention, since the cells in a normal state in the processing tank are held for a certain period of time, it is detected by a temperature sensor, a pH sensor or the like in the processing tank that the cells are damaged due to abnormal processing. In this case, first, the operation of temporarily storing and discharging the processing solution for temporarily storing the bacteria intermittently according to the present invention in the storage tank is stopped, and the processing is normally performed in the storage tank. The cells at the time of storage are stocked, and during that time, an operation of returning the inside of the processing tank to a normal state is performed. After that, the cells kept in the storage tank are put into the treatment tank and restarted, whereby the device can be quickly returned to the normal state.

Depending on the degree of damage of the cells in the treatment tank, the operation of returning the inside of the treatment tank to a normal state is performed, and then the cells retained in the storage tank are put into the treatment tank, and the treatment is immediately performed. In some cases it is possible to continue.

The size of the storage tank of the present apparatus is determined by the growth rate of the bacterial cells used, the size of the processing tank, and the allowable time for recovery after trouble. The capacity is preferably about 0.1% to 10%. The size of the storage tank is preferably set slightly larger when the growth rate of the bacterial cells is low or when the allowable time for recovering from the trouble is short.

The form of the storage tank may be a general tank shape, and if the capacity of the storage tank is small, a thick pipe may be used and is not particularly limited.

The setting of the replacement time for feeding the solution in the treatment tank or the treated water into the storage tank of the present apparatus is preferably determined in consideration of the time-dependent change in the mortality when the cells are stored in the storage tank. In addition, the time required until the cells stored and held under the conditions of the storage tank are completely eliminated is the maximum replacement interval. Further, it is necessary to set the replacement time longer than the time during which the abnormality detection system of the apparatus can detect the abnormality after the processing tank is in an abnormal condition. This is because microorganism treatment often has a long residence time of several hours to several days, and the capacity of the tank with respect to the inflow water is large. Is very low in concentration and difficult to detect. For this reason, even when the processing tank is actually in abnormal conditions, the detection by the sensor may be considerably delayed in time, and it is necessary to provide a replacement interval with a margin more than the time difference. Otherwise, when cells are introduced from the temporary storage detention part by the treatment tank or more, and when starting up, the cells in the temporary storage detention part have already been affected by damage, so the cells in the temporary storage detention part have already been affected. Then it cannot be started. The replacement time is determined by comprehensively determining these.

Normally, the intervals of the replacement time can be set at regular intervals by a timer or the like, but may be irregular intervals depending on the operation state of the apparatus. For example, when it is known that the apparatus is to be stopped at night or on holidays, a method of setting the intervals at unequal intervals can be adopted. This interval is determined according to the residence time and the characteristics of the bacteria, but the time is particularly preferably from 5 hours to 3 days.

In setting the storage time and the capacity of the storage tank, a method of setting the storage tank to conditions under which bacteria can easily grow,
For example, when dealing with aerobic bacteria, the method of aeration in the storage tank, control of pH, temperature, etc.,
If there is an effective additive such as an inorganic salt to keep the bacteria growing for a longer time, a method of adding such an additive or a method of adding a nutrient source such as wastewater is also effective.

As to the method of sending liquid to the storage tank, a method using a pump, a method using an air lift, a method of sending a liquid by head difference with a branch in the middle of the effluent line, and a method of feeding the storage tank inside the processing tank When the setting is made, a method may be used in which a valve is provided in a portion communicating with the processing tank and the valve is opened and closed. The method of draining the liquid from the storage tank also includes a method of pushing out by liquid feeding, a method of overflowing, and a method of spontaneously flowing down by a water head.

This method can be used for various applications, and there is no particular limitation on the application and the treatment liquid, but the effect is particularly large when the treatment liquid is mainly composed of waste water from a polyester fabric which is subjected to weight reduction treatment with sodium hydroxide. This is the case for drainage. This is because the pH of the processing liquid is high and fluctuates,
In addition, when the temperature is high, if a problem occurs in a part of the pH control or the temperature control, for example, when the temperature control is not performed, a situation in which the processing liquid of 90 ° C. or more flows into the processing tank. It can happen, causing the bacteria in the treatment tank to be completely destroyed. However, according to the present invention, even in such an extermination case, it is possible to quickly start up using the bacteria that have been temporarily stored.

[0033]

EXAMPLES (Example) In a processing tank 1 having a capacity of 300 liters (L), the liquid to be treated was treated with microorganisms for a residence time of 6 hours. At this time, the storage tank 3 having a capacity of 10 L was provided outside the processing tank, and the replacement interval of the storage tank 3 was set to 24 h by the timer 6. This group of microorganisms has the highest activity around pH 8,
Since it is known that bacteriolysis occurs when the pH is 2 or less, the pH was constantly monitored, and the pH was automatically adjusted to 8 with sodium hydroxide and sulfuric acid.

In order to simulate a trouble situation, a large amount of sulfuric acid is put into the treatment tank at a time to adjust the pH to 2, and the treatment tank 1
The microbial cells inside were lysed.

After setting the simulated trouble, the liquid in the processing tank 1 is drained immediately, washed with water, and filled with the liquid to be processed.
Then, normal cells were introduced into the culture, and the culture was started. At this time, the bacterial cell concentration in the treatment tank 1 became the same as the normal concentration in 24 hours after the occurrence of the simulated trouble.

(Comparative Example) The liquid to be treated was subjected to the microorganism treatment in the same microorganism treatment tank 1 having a capacity of 300 L as in the example for a residence time of 6 h. This group of microorganisms has the highest activity around pH 8,
Since it is known that bacteriolysis occurs when the pH is 2 or less, the pH was constantly monitored, and the pH was automatically adjusted to 8 with sodium hydroxide and sulfuric acid.

In order to simulate a trouble situation, a large amount of sulfuric acid was put into the treatment tank 1 at a time to adjust the pH to 2, and the microbial cells inside the treatment tank 1 were lysed.

After setting the simulated trouble, the frozen stock strain 15m
L was taken out and cultured in a 0.3 L culture tank, and a predetermined bacterial concentration was obtained in 24 hours. The culture solution cultured at 0.3 L was used as a seed bacterium, and further cultured in a 6 L culturing tank, and a predetermined bacterial concentration was obtained in 24 h. This was put into a 300 L microbial treatment tank 1 as a seed bacterium, and the concentration of the bacterium became the same as that in the normal state in the treatment tank in 24 h. A total of 72 hours from setting the simulated trouble to returning to normal processing in the processing tank was required.

[0039]

According to the present invention, normal processing can be quickly restored after trouble such as killing of bacteria in the liquid treatment method using microorganisms.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a liquid processing apparatus utilizing microorganisms of the present invention.

FIG. 2 is a flowchart showing another example of the liquid processing apparatus utilizing microorganisms of the present invention.

[Explanation of symbols]

 1: Treatment tank 2: Stirrer 3: Storage tank 4: Raw material or treated water inflow line 5: Treated water outflow line 6: Timer 7: Air diffuser 8: Air lift

Claims (7)

[Claims] 1. A method for treating a liquid containing microorganisms, the method comprising a step of intermittently temporarily storing a part of the liquid in a treatment tank containing the microorganisms. 2. The capacity for temporary storage is 0.1 to 1 of the processing tank.
The method for treating liquid using microorganisms according to claim 1, wherein the concentration is 0%. 3. The method for treating liquid using microorganisms according to claim 1, wherein an interval of the step of intermittently storing is 5 hours to 3 days. 4. The method for treating liquid utilizing microorganisms according to claim 1, wherein the treatment liquid is wastewater mainly composed of wastewater treated to reduce the weight of polyester fabric with sodium hydroxide. 5. A liquid processing apparatus utilizing microorganisms, comprising a processing tank having microorganisms having at least an inlet for the liquid to be processed and an outlet for the processing liquid, wherein part of the liquid in the processing tank containing the microorganisms is intermittently temporarily stored. A liquid processing apparatus utilizing microorganisms, comprising: 6. The liquid processing apparatus utilizing microorganisms according to claim 5, wherein the capacity of the temporary storage means is 0.1 to 10% of the processing tank. 7. The intermittent preservation cycle is set to 5 hours to 3 hours.
The liquid processing apparatus utilizing microorganisms according to claim 5 or 6, further comprising means that can be set during the day.