JP2002018470A - Organic wastewater treatment method and apparatus therefor - Google Patents

Abstract

(57) [Summary] [Problem] To maximize the efficiency of sludge reduction and to maintain the quality of treated water appropriately. SOLUTION: A wastewater containing organic matter is discharged into a first biological treatment tank 2.
After aeration, the organic matter is decomposed by microorganisms, and solid-liquid separation is performed in the first sedimentation tank 3. Then, the supernatant water separated in the first sedimentation tank 3 is disinfected in the discharge part 4 and discharged out of the system. The sludge deposited at the bottom of the first sedimentation tank 3 is returned to the first biological treatment tank 2, while the sludge from the first sedimentation tank 3 is introduced into the cell membrane crusher 7, After crushing the cell membranes of the organisms constituting the sludge, the organic wastewater is treated by returning to the first biological treatment tank 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic wastewater treatment apparatus, and more particularly to a wastewater treatment method and apparatus having a cell membrane crushing apparatus.

[0002]

2. Description of the Related Art Conventionally, excess sludge discharged from a wastewater treatment facility such as a sewage treatment plant by an activated sludge method is concentrated and dewatered.
They have been landfilled or incinerated. However, in recent years, problems such as the capacity of receiving landfills and the cost of incineration have arisen, and reduction of excess sludge has been required. One of the sludge reduction methods is mechanical crushing, oxidizing and reducing agents, A method has been proposed in which sludge whose cell membrane has been crushed by a cell membrane crushing apparatus such as an alkali or a heating and pressurizing apparatus is returned to an aerobic digestion or biological treatment tank.

[0003]

However, in the above-mentioned method, the sludge obtained by crushing the cell membrane becomes a load on the biological treatment tank, and depending on the condition of the biological treatment tank, the sludge reduction efficiency is reduced and the quality of the treated water is deteriorated. . SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic wastewater treatment method and apparatus capable of maximizing sludge reduction efficiency and appropriately maintaining treated water quality. Is what you do.

[0004]

Means for Solving the Problems The present invention focuses on a cell membrane crushing method adapted to the treatment state of a biological treatment tank, and aims at maximizing sludge reduction efficiency and properly maintaining treated water quality. The present invention has been completed based on the knowledge of the processing method and apparatus to be performed, and the above-mentioned problems can be solved by the invention described in each claim as a result of the research of the present inventors on the cell membrane crushing method.

That is, in the organic wastewater treatment method according to the first aspect of the present invention, wastewater containing organic matter is aerated in a first biological treatment tank to decompose organic matter by microorganisms, and solidified in a first sedimentation tank. After liquid separation, the supernatant water separated in the first sedimentation tank is disinfected in the discharge section and discharged outside the system, and the sludge deposited on the bottom of the first sedimentation tank is subjected to the first biological treatment. While returning to the tank, the sludge from the first sedimentation tank is introduced into a cell membrane crusher, and the cell membrane of the organisms constituting the sludge is crushed by the cell membrane crusher. This is to return it. According to this, by crushing the cell membrane of the organisms constituting the excess sludge and returning it to the biological treatment tank,
This aims to maximize the efficiency of sludge reduction and maintain the quality of treated water appropriately.

According to a second aspect of the present invention, there is provided an organic wastewater treatment method, wherein wastewater containing organic matter is aerated in a first biological treatment tank to decompose organic matter by microorganisms, and solid-liquid separation is performed in the first sedimentation tank. After that, the supernatant water separated in the first sedimentation tank is disinfected in the discharge section and discharged out of the system, and the sludge deposited on the bottom of the first settling tank is subjected to the first sedimentation.
The sludge from the first settling tank is stored in a storage tank, and the sludge from the first settling tank and the sludge from the storage tank are introduced into a cell membrane crushing device. After the cell membrane of the organism constituting the sludge is crushed by the crushing device, the sludge is returned to the first biological treatment tank. Thus, similarly to the first aspect of the present invention, the sludge reduction efficiency is maximized and the quality of the treated water is appropriately maintained.

According to a third aspect of the present invention, there is provided the organic wastewater treatment method according to the first or second aspect, wherein the sludge whose cell membrane is crushed by the cell membrane crusher is used as a second biological treatment tank. After the sludge is returned to the first biological treatment tank, the sludge from the second biological treatment tank is subjected to solid-liquid separation in the second sedimentation tank, and the supernatant water separated in the second sedimentation tank is returned to the first biological treatment tank. On the other hand, the sludge deposited on the bottom of the second settling tank is returned to the sludge storage tank and / or the cell membrane crusher. According to this, after the sludge is crushed by the cell membrane crushing device and returned to the second biological treatment tank, the sludge flowing from the second biological treatment tank is subjected to solid-liquid separation in the second sedimentation tank. , The second
Returning the supernatant water separated in the sedimentation tank to the first biological treatment tank, and returning sludge deposited on the bottom of the second sedimentation tank to the sludge storage tank and / or cell membrane crushing device by a second return drawing device. To further maximize sludge reduction efficiency and maintain the quality of treated water properly.

According to a fourth aspect of the present invention, there is provided the organic wastewater treatment method according to the first, second, or third aspect, wherein the organic wastewater is dissolved in the organic solution discharged from the cell membrane crushing apparatus. The removal of the phosphorus component is performed by a phosphorus removal device. Thereby, similarly to the first aspect of the invention, the sludge reduction efficiency is maximized, the quality of the treated water is appropriately maintained, and the phosphorus component dissolved in the organic solution discharged from the cell membrane crusher is removed. Is what you can do.

According to a fifth aspect of the present invention, there is provided an organic wastewater treatment method according to the first or second or third or fourth aspect, wherein the first biological treatment tank or the second biological treatment tank is provided. A DO meter is provided in the biological treatment tank 2 and the cell membrane crushing apparatus is operated when the DO value decreasing rate in the immediately preceding non-aeration state is equal to or less than a predetermined value. To stop the operation of the device.

According to a sixth aspect of the present invention, there is provided the organic wastewater treatment method according to the fifth aspect,
An ORP meter is provided in the first biological treatment tank or the second biological treatment tank, and the relative value of the decreasing rate of the ORP value in the immediately preceding non-aeration state to the decreasing rate of the DO value in the immediately preceding non-aerated state is a predetermined value. In the above case, the operation of the cell membrane crusher is stopped.

According to a seventh aspect of the present invention, there is provided the organic wastewater treatment method according to the fifth or sixth aspect, wherein a pH meter is provided in the first biological treatment tank or the second biological treatment tank. The aeration amount is reduced when the pH value is equal to or less than a predetermined value, and the aeration amount is increased when the pH value is equal to or more than the predetermined value.

[0012] The organic wastewater treatment method according to the invention of claim 8 is the organic wastewater treatment method of claim 7,
A water temperature gauge is provided in the first biological treatment tank or the second biological treatment tank, and the aeration amount is relatively changed at a predetermined pH value depending on the water temperature.

According to a ninth aspect of the present invention, there is provided the organic wastewater treatment method according to the fifth or sixth or seventh or eighth aspect, wherein the first biological treatment tank or the first biological treatment tank is provided. An MLSS meter is provided in the biological treatment tank 2 and the ML
When the SS value is equal to or more than a predetermined value, the sludge is returned to the sludge storage tank and / or the cell membrane crusher, and when the SS value is equal to or less than the predetermined value, the sludge is returned to the first biological treatment tank or the second biological treatment tank.

According to the fifth to ninth aspects of the present invention, the operation of the cell membrane crushing device and the return drawing device is controlled by the MLSS value of the biological treatment tank, the DO value decreasing speed in the immediately preceding non-aeration state, and the DO value decreasing. By controlling in accordance with the relative value of the ORP value decreasing speed or the increasing speed of the MLSS value in the immediately preceding non-aeration state with respect to the speed, it is possible to operate under an optimal load condition, so that sludge is not deteriorated without deteriorating the quality of treated water. Reduction can be implemented. In addition, the operation of the aeration device is not limited to the DO value of the biological treatment tank, but also the pH value and the
By controlling in accordance with the relative value to the value, it is possible to carry out aeration with no excess or deficiency, to secure an optimum activated sludge growth environment, and to treat organic wastewater.

An organic wastewater treatment apparatus according to the invention according to claim 10 is a biological treatment tank for decomposing wastewater containing organic matter by a microorganism, an aerator for aerating wastewater in the biological treatment tank, and an organic wastewater treatment apparatus. A sedimentation tank for solid-liquid separation of the sludge, a discharge section for disinfecting the supernatant water separated in the sedimentation tank and discharging the sludge to the outside of the system, and a return extraction device for extracting sludge from the sedimentation tank and returning it to the biological treatment tank An organic wastewater treatment apparatus comprising: a sludge from the sedimentation tank, a cell membrane crushing apparatus for crushing a cell membrane of an organism constituting the sludge and returning the sludge to the biological treatment tank. DO value in tank and O
The RP value, the pH value, the water temperature, the MLSS value, the value obtained by calculating the rate of decrease of the DO value and the value obtained by calculating the rate of decrease of the ORP value are used as the antecedent variables, and the operation output to the cell membrane crusher and A control device for performing a process based on a plurality of fuzzy control rules having an aeration amount output to the aeration device and a pull-out instruction output to the return drawing device as a consequent variable, wherein the pH meter, the DO meter, and the water temperature meter are provided. And the output signals of the ORP meter and the MLSS meter are input to the control device, and a control signal based on the output signal based on the fuzzy control rules is transmitted to the cell membrane crushing device, the aeration device, and the return extraction device. It is intended to output.

Thus, the sludge reduction efficiency is maximized, the quality of treated water is appropriately maintained, and the fuzzy control rules based on the analysis of characteristics from experimental data or the analysis of a field test at an actual wastewater treatment plant. By setting the membership function, it is possible to perform optimal automatic control for 24 hours, and it is possible to significantly reduce maintenance costs. Further, the fuzzy control rules or membership functions can be easily changed, and can be changed on site or remotely, so that maintenance performance can be greatly improved.

An organic wastewater treatment apparatus according to the invention according to claim 11 is a biological treatment tank for decomposing wastewater containing organic matter by a microorganism, an aerator for aerating wastewater in the biological treatment tank, and an organic wastewater treatment apparatus. A sedimentation tank for solid-liquid separation of the sludge, a discharge section for disinfecting the supernatant water separated in the sedimentation tank and discharging the sludge to the outside of the system, and a return extraction device for extracting sludge from the sedimentation tank and returning it to the biological treatment tank A storage tank for storing the sludge from the sedimentation tank, and an organic wastewater treatment device having a cell membrane crushing device for crushing a cell membrane of an organism constituting the sludge and returning the sludge to the biological treatment tank. The DO value, the ORP value, the pH value, the water temperature, the MLSS value, the value obtained by calculating the rate of decrease of the DO value, the value obtained by calculating the rate of decrease of the ORP value, and the value obtained by calculating the rate of increase of the MLSS value in the biological treatment tank Is the antecedent variable, and A control device that performs a process based on a plurality of fuzzy control rules with a consequent part variable as an operation output to the cell membrane crushing device, an aeration amount output to the aeration device, and an extraction instruction output to a return extraction device, The pH meter, the DO meter, the water temperature meter, the ORP meter, and the MLSS
Each output signal of the meter is input to the control device, and a control signal based on the output signal based on the fuzzy control rule is output to the cell membrane crushing device, the aeration device, and the return extraction device. Things.

As a result, the sludge reduction efficiency is maximized and the treated water quality is properly maintained, and the characteristic analysis from experimental data or the field test at an actual wastewater treatment plant is performed. By setting fuzzy control rules and membership functions based on analysis,
Optimal automatic control can be performed for 24 hours, and maintenance cost can be significantly reduced. Further, the fuzzy control rules or membership functions can be easily changed, and can be changed on site or remotely, so that maintenance performance can be greatly improved.

The organic wastewater treatment apparatus according to the invention of claim 12 is the organic wastewater treatment apparatus according to claim 10 or 11, wherein a phosphorus removing device is provided on the sludge outflow side of the cell membrane crushing apparatus or the inflow side of the discharge section. The structure is such that the phosphorus component dissolved in the organic solution discharged from the cell membrane crushing device is removed. Thereby, the phosphorus eluted from the crushed sludge or the phosphorus dissolved in the supernatant water of the settling tank flowing into the discharge section is adsorbed by the phosphorus removing device, so that efficient phosphorus recovery is performed, and the phosphorus is removed from the treated water. Spills can be restricted.

An organic wastewater treatment apparatus according to a thirteenth aspect of the present invention is the organic wastewater treatment apparatus according to the tenth or eleventh aspect, wherein the cell membrane crushing apparatus uses a bead mill made of glass beads. The glass beads have a content of lithium oxide + sodium oxide + potassium oxide of about 8% to 20%, and glass beads having a diameter of about 0.1 mm to 1 mm contain 70% or more of the whole. The purpose is to perform cell membrane crushing with glass beads. This allows
Cell membranes can be efficiently crushed, and sludge can be reduced.

[0021]

Embodiments of the present invention will be described below. In FIG. 1, the organic wastewater is first placed in a raw water tank 1
Is stored in Organic wastewater stored in the raw water tank 1 is the first
Is sent to the biological treatment tank 2 for biological treatment of decomposition of organic substances by microorganisms, and then sent to the first sedimentation tank 3 for solid-liquid separation.

Here, the first biological treatment tank 2 generally performs biological treatment by an activated sludge method or a contact aeration method by a first aeration device 17 described later.

The supernatant liquid generated by the solid-liquid separation in the first settling tank 3 is sent to the discharge section 4 and discharged.

On the other hand, the sludge deposited on the bottom of the first sedimentation tank 3 by solid-liquid separation is returned to the first biological treatment tank 2 as returned sludge by the first return drawing device 5, or as excess sludge. The sludge is directly sent to the cell membrane crushing device 7 or sent to the sludge storage tank 6.
From the cell membrane crusher 7.

The excess sludge sent to the cell membrane crusher 7 is
After being crushed by the cell membrane crushing device 7 to be converted into an organic solution and returned to the second biological treatment tank 8, biological treatment is performed in the second biological treatment tank 8 in the same manner as described above.

The sludge from the second biological treatment tank 8 is sent to a second sedimentation tank 9 where it is separated into solid and liquid. The sludge deposited on the bottom by solid-liquid separation in the second settling tank 9 is returned to the second sludge pulling device 10 as second sludge.
After being returned to the biological treatment tank 8 or being sent to the sludge storage tank 6 as surplus sludge, it is returned to the cell membrane crushing device 7 again.
Alternatively, it is sent directly to the cell membrane crushing device 7 and returned to the second biological treatment tank 8 before being subjected to biological treatment.

The supernatant of the second settling tank 9 is supplied from the phosphorus removing device 11 to the raw water tank 1 or the first biological treatment tank 2.
Will be returned to In addition, it is also possible to discharge from the phosphorus removal device 11 to the discharge section 4.

In this way, by returning the excess sludge to each biological treatment tank while crushing the cell membrane, the excess sludge can be reduced as a result.

Here, as a control method of the control device 19 to be described later, when the MLSS value of the first biological treatment tank 2 rises, if the load of the second biological treatment tank 8 is low, the control device 19 When it is determined, the surplus sludge is directly sent to the cell membrane crushing device 7 without being sent to the sludge storage tank 6 by the first return drawing device 5.

On the other hand, when the control device 19 determines that the load of the second biological treatment tank 8 is high when the MLSS value of the first biological treatment tank 2 increases, the first return / pulling-out device 5 The excess sludge is sent from the sludge storage tank 6 to the cell membrane crushing device 7 after the controller 19 determines that the load on the second biological treatment tank 8 has become low.
Send to

Further, even when the MLSS value of the first biological treatment tank 2 rises sharply so as to exceed the treatment capacity of the cell membrane crushing device 7, surplus sludge is sent to the sludge storage tank 6 and the first biological If the MLSS value of the treatment tank 2 is restored to a normal value and the load of the second biological treatment tank 8 is low, the controller 19
Is sent from the sludge storage tank 6 to the cell membrane crusher 7.

Similarly, when the control device 19 determines that the load of the second biological treatment tank 8 is low when the MLSS value of the second biological treatment tank 8 increases, the second return pull-out operation is performed. The excess sludge is directly sent to the cell membrane crushing device 7 without being sent to the sludge storage tank 6 by the device 10.

On the other hand, when the control device 19 determines that the load of the second biological treatment tank 8 is high when the MLSS value of the second biological treatment tank 8 increases, the second return / pulling-out device The excess sludge is sent to the sludge storage tank 6 by 10 and the MLSS value of the second biological treatment tank 8 is restored to a normal value, and the excess sludge is stored after the control device 19 determines that the load has decreased. It is sent from the tank 6 to the cell membrane crusher 7.

Further, even when the MLSS value of the second biological treatment tank 8 rises sharply so as to exceed the processing capacity of the cell membrane crushing device 7, surplus sludge is sent to the sludge storage tank 6, After the control device 19 determines that the MLSS value of the treatment tank 8 has recovered to a normal value and the load has become low, the MLSS value is sent from the sludge storage tank 6 to the cell membrane crushing device 7.

As described above, by transmitting the excess sludge directly to the cell membrane crushing device 7 without sending it to the sludge storage tank 6 except when necessary, energy saving and time reduction can be achieved.

The cell membrane crusher 7 is not particularly limited, but is preferably crushed by a wet bead mill or ultrasonic waves.

The wet bead mill breaks the cell membrane by a shearing / grinding force generated by rotating a rotating disk installed in a cylindrical container to agitate the beads filled in the container.

The filling rate of the beads in the cylindrical container is about 75 to
The peripheral speed of the 90% rotating disk is approximately 8 to 20 m / sec, the residence time in the cylindrical container is 30 seconds to 20 minutes, and the material of the liquid contact portion in the cylindrical container and the rotating disk are not particularly limited, but polyurethane. Is practically preferable.

As a bead material, a glass bead mill for crushing a cell membrane with glass beads having a diameter of about 0.1 to 1.0 mm containing a content of lithium oxide + sodium oxide + potassium oxide of about 8% to 20% was used. .

The reason is that the size of the cells is about 1 μm, and the most efficient result is obtained when the cell size is about 50 μm (0.05 mm) for crushing the cell membrane with a bead mill. In order to prevent the beads from flowing out due to the small size of the beads, a filter for preventing the beads from flowing out is required. If the filter is too fine, clogging occurs due to debris other than cells. For this reason, practicality comes out usually by making a diameter about 0.1-1.0 mm and making a filter a little large.

Although the cell membrane is dissolved by alkali, the smaller the total amount of lithium oxide + sodium oxide + potassium oxide in the glass, the less consumption is required, but the cost is high, and lithium oxide + sodium oxide + If the total amount of potassium oxide exceeds about 20%, the dissolution of the alkali in water is large, the consumption increases, and it becomes necessary to additionally supply glass beads. For this reason, the frequency of replacing glass beads increases, which is not practical in terms of management.

Therefore, in order to reduce maintenance once a week or less, it is economical and efficient to keep the total content of lithium oxide + sodium oxide + potassium oxide at about 8% to 20%. Cell membrane disruption effect is obtained.

FIG. 1 shows a case where a single biological treatment tank is used to treat organic wastewater and treat sludge that has been converted into an organic solution by crushing. The sludge crushed by the cell membrane crusher 7 is biologically treated in the second biological treatment tank 8 and the solid-liquid separation is performed in the second sedimentation tank 9 because the treatment capacity in the treatment tank may be exceeded. As a result, an increase in load on the first biological treatment tank 2 due to the sludge crushed by the cell membrane crushing device 7 and converted into an organic solution can be avoided, and as a result,
Deterioration of the water quality of the discharge section 4 can be avoided. The supernatant of the second sedimentation tank 9 can be sent to the raw water tank 1 or discharged to the discharge section 4.
May be sent to

Here, when there is no danger of increasing the load on the first biological treatment tank 2 due to the sludge formed into an organic solution by the crushing, the second biological treatment tank 8, the second sedimentation tank 9, and the second
A single biological treatment tank without the return extraction device 10 (FIG. 3)
An embodiment will be described. ) Can also be performed.

Further, the elution of the phosphorus accumulated in the cell body due to the disruption of the cell membrane was determined in the form of particulate metal oxide,
For example, it is possible to cope with this by incorporating a phosphorus removal step of adsorbing phosphorus into an aluminum oxide called activated alumina in a processing apparatus.

In the above-described embodiment, the position for inserting the phosphorus removing step is provided immediately after the second sedimentation tank 9, but at least one position is provided immediately after the cell membrane crushing device 7 and immediately before the discharge section 4. Is preferable. Also, in the case of a single biological treatment tank without the second biological treatment tank 8 and the second sedimentation tank 9 (in the embodiment of FIG. 3 described later), immediately after the cell membrane crushing device 7 and immediately before the discharge section 4 It is preferable that at least one or more be provided.

In the phosphorus removing step, phosphorus is adsorbed and removed by passing waste water through a container filled with the particulate metal oxide. The removal capacity of phosphorus can be improved by increasing the contact area between the wastewater and the particulate metal oxide.For example, the wastewater can be atomized and introduced into the container,
By reducing the particle size of the metal oxide, the ability to remove phosphorus can be improved. Practically, the particle size of the metal oxide is preferably about 1 to 10 mm in consideration of strength.

Also, depending on the type of the metal oxide, the optimum p
There is H, and the ability to remove phosphorus can be improved by adjusting the pH before introducing the wastewater into the container.
The pH is generally adjusted by chemicals. For example, the optimum pH of aluminum oxide called activated alumina is adjusted.
Is about 5.5 to 6.0, the pH can be adjusted to about 5.5 to 6.0 by aerating with a second aerator 18 described later in FIG. The removal of phosphorus can be performed without performing.

As an actual control method, the first biological treatment tank 2 and the second biological treatment tank 8 are provided with a DO meter 12, an ORP meter 13, a pH meter 14, a water temperature meter 15, an MLS
An S meter 16 is provided, and each detection signal is input to the control device 19.

The control device 19 is, for example, a computer having a signal conversion unit for converting each detection signal into a digital signal, a storage unit, and a program. This control device 19 is based on the input values. The cell membrane crushing device 7, the first aeration device 17 in the first biological treatment tank 2, the second aeration device 18 in the second biological treatment tank 8, the first return and extraction device. 5. Control the second return / pull-out device 10.

As control methods, DO value, ORP value, p
The antecedent part is a value obtained by calculating a decrease rate after non-aeration from the H value, the water temperature, the MLSS value, and the DO value, a value obtained by calculating a decrease rate of the ORP value after non-aeration, and a value obtained by calculating an increase rate of the MLSS value. Variable, and the operation output to the cell membrane disruption device 7, the amount of aeration to the first aeration device 17 and the second aeration device 18, the first
The cell membrane crushing device 7, the first aeration device 17 and the second aeration device 18 are based on a plurality of fuzzy control rules in which the extraction instruction to the return extraction device 5 and the second return extraction device 10 is a consequent variable. , The first return pull-out device 5 and the second return pull-out device 10 are controlled.

Note that the DO value and the ORP value decrease rate after non-aeration are determined, for example, by stopping the first aeration device 17 and the second aeration device 18 for a certain period of time at regular intervals, and measuring the DO total
2. It is calculated from each detection signal of the ORP meter 13.

The fuzzy control rules include the second
The operation of the cell membrane crusher 7 is performed when the rate of decrease of the DO value during the non-aeration treatment immediately before the biological treatment tank 8 is equal to or less than a predetermined value, and the operation of the cell membrane crusher 7 is stopped when the DO value is equal to or more than the predetermined value. And at the same time, when the relative value of the decreasing rate of the ORP value with respect to the decreasing rate of the DO value of the second biological treatment tank 8 is equal to or more than a predetermined value, the operation of the cell membrane crushing device 7 is stopped (a ), When the pH value of the first biological treatment tank 2 or the second biological treatment tank 8 falls below a predetermined value,
The aeration amount of the aeration device 17 and the second aeration device 18 is decreased, and the aeration amount is increased when the aeration amount exceeds a predetermined value.
An aeration control rule (b) for relatively changing the aeration amount depending on the water temperatures of the first biological treatment tank 2 and the second biological treatment tank 8, and the MLSS value of the first biological treatment tank 2 is set to a predetermined value. If the value is equal to or more than the predetermined value, the control rule (c) for extracting the sludge from the first return / extraction device 5 to the sludge storage tank 6 or the cell membrane crushing device 7 indicates that the increase rate of the MLSS value of the first biological treatment tank 2 is equal to or more than the predetermined value. And when the MLSS value is equal to or greater than a predetermined value,
A control rule (d) for extracting surplus sludge from the first return drawing apparatus 5 into the sludge storage tank 6, MLSS in the first biological treatment tank 2
After the rate of increase of the value is equal to or higher than a predetermined value and the MLSS value is equal to or higher than a predetermined value, if the MLSS value is equal to or lower than a predetermined value after a predetermined time, the control rule (e) for sending the sludge storage tank 6 to the cell membrane crushing device 7 When the MLSS value of the second biological treatment tank 8 becomes equal to or more than a predetermined value, a control rule (f) for extracting sludge from the second return drawing apparatus 10 to the sludge storage tank 6 or the cell membrane crushing apparatus 7; When the MLSS value of No. 8 becomes equal to or less than a predetermined value, a control rule (g) for sending out excess sludge from the sludge storage tank 6 to the cell membrane crushing device 7, and the ML of the second biological treatment tank 8
When the increasing speed of the SS value is equal to or higher than a predetermined value and the MLSS value is equal to or higher than the predetermined value, the excess sludge is removed from the second return / pulling-out device 10.
(H) that the MLSS value in the second biological treatment tank 8 is equal to or higher than a predetermined value and the MLSS value is equal to or higher than a predetermined value, and then the MLSS value after a predetermined time. Is set to a predetermined value or less, a control rule (i) for sending out from the sludge storage tank 6 to the cell membrane crushing device 7 is provided.

Table 1 shows an example in which the above control rules are arranged as fuzzy control rules. In the control rules shown in Table 1,
The and part of and are the antecedent variables shown in Table 2 of the fuzzy control rules (for example, in (a), the part is X1, X2),
Is a consequent variable shown in Table 3 (for example,
In (a), the part corresponds to Y1).

[0055]

[Table 1]

[0056]

[Table 2] [Antecedent variable] X1 = DO at the time of non-aeration treatment immediately before the second biological treatment tank 8
X2 = OR at the time of non-aeration processing immediately before the second biological treatment tank 8
The relative value of the decreasing rate of the P value to the decreasing rate of the DO value is not more than a predetermined value. X3 = the pH value of the first biological treatment tank 2 is not less than a predetermined value. X4 = relative to the pH value of the water temperature of the first biological treatment tank 2. The value is equal to or less than a predetermined value. X5 = The pH value of the second biological treatment tank 8 is equal to or more than a predetermined value. X6 = The relative value of the water temperature of the second biological treatment tank 8 to the pH value is equal to or less than a predetermined value. X7 = The first biological treatment tank. X8 = the MLSS value of the first biological treatment tank 2 is greater than or equal to a predetermined value. X9 = the MLSS value of the first biological treatment tank 2 is greater than or equal to a predetermined value. After a predetermined value, the MLSS value is equal to or less than a predetermined value after a predetermined time. X10 = The MLSS value of the second biological treatment tank 8 is equal to or more than a predetermined value. X11 = The MLSS value of the second biological treatment tank 8 is predetermined. Below the value X12 = the rate of increase of the MLSS value of the second biological treatment tank 8 is above a predetermined value. After the rate of increase of the MLSS value of the processing tank 8 is equal to or more than a predetermined value and the MLSS value is equal to or more than a predetermined value,
After a certain time, the MLSS value is equal to or less than a predetermined value.

[0057]

[Table 3] [Consequent variables] Y1 = operation command to cell membrane crushing device 7 Y2 = aeration amount instruction to first aeration device 17 Y3 = aeration amount instruction to second aeration device 18 Y4 = first Instruction to extract sludge from the return extraction device 5 to the sludge storage tank 6 or the cell membrane crushing device 7 Y5 = instruction to extract sludge from the first return extraction device 5 to the sludge storage tank 6 Y6 = instruction to extract sludge from the sludge storage tank 6 to the cell membrane crushing device 7 Instruction to send sludge to the sludge storage tank 6 or cell membrane crushing device 7 from the second return and extraction device 10 Y8 = Instruction to send sludge from the sludge storage tank 6 to the cell membrane crushing device 7 Y9 = Second Instruction to withdraw sludge from return extraction unit 10 to sludge storage tank 6 Y10 = Instruction to send sludge from sludge storage tank 6 to cell membrane crusher 7

Here, the antecedent variable is normalized to a value from -1 to +1 by the maximum value and the minimum value with respect to the input signal.
In the consequent part, variables are similarly normalized to values from -1 to +1. From the standard values of the antecedent variables, the antecedent part fitness from 0 to 1 is calculated based on the membership function by the min-max centroid method, and similarly from 0 to 1 from the standard values of the consequent variables. Calculate the degree of conformity of the consequent part up to.

Then, for each control rule, the minimum value (min) of the antecedent part conformity is multiplied by the membership function of the consequent part, and all control rules are synthesized using the maximum value (max).
Then, the center of gravity of the combined membership function is set as the output value of the control device 19.

As described above, the arithmetic processing is performed in the control device 19 based on the control rules of Table 1 composed of the antecedent variables of Table 2 and the consequent variables of Table 3, and the optimal cell membrane crushing is performed.
Aeration of each biological treatment tank, return and extraction of sludge. The target predetermined value in each antecedent variable is set to a value corresponding to the actual site, so that control can be performed in accordance with the actual conditions of the site.

FIG. 2 shows the flow of processing in the control device 19. When the power supply of the control device 19 is started, in step S1, a membership function and a control rule relating to fuzzy control are read from the storage unit, and initial processing at the time of start is performed.

In step S2, the first biological treatment tank 2
And the DO total 12, the ORP total 13, and the second biological treatment tank 8
Detection signals are input from the pH meter 14, the water temperature meter 15, and the MLSS meter 16, and as shown from [0053] to [0060], in step S3, the standardization of the antecedent and consequent is performed based on each detection data. Do.

After calculating the control output value based on the membership function and the control rule in step S4, the cell membrane crushing instruction, the aeration amount, and the return pull-out instruction are output in step S5. Is performed, if it is determined that the processing is not to be terminated, the processing is repeated from step 2; otherwise, the processing is terminated.

In the embodiment shown in FIG. 3, the first biological treatment tank 2 and the second biological treatment tank 8 are configured as a single biological treatment tank (first biological treatment tank 2) in FIG. The case where the sludge storage tank 6 is omitted is shown, and the rest is configured in the same manner as the above-described embodiment. That is, in FIG. 3, the organic wastewater is stored in the raw water tank 1. Raw water tank 1
Is discharged to the first biological treatment tank 2 and subjected to biological treatment in the same manner as described above.

Next, the mixture is sent to the first settling tank 3 to be separated into solid and liquid. The supernatant liquid generated by the solid-liquid separation in the first settling tank 3 is sent to the discharge section 4 and discharged.

On the other hand, the sludge deposited at the bottom of the first sedimentation tank 3 by solid-liquid separation is returned to the first biological treatment tank 2 as returned sludge by the first return drawing device 5. Or
It is sent directly to the cell membrane crusher 7 as surplus sludge.

This excess sludge is converted into an organic solution by being crushed by the cell membrane crusher 7, returned to the first biological treatment tank 2, and then subjected to biological treatment again. As a result, excess sludge can be reduced. it can.

Here, when the control device 19 determines that the load on the first biological treatment tank 2 is low when the MLSS value of the first biological treatment tank 2 rises, it is sent to the cell membrane crushing apparatus 7. .

In the first biological treatment tank 2, similarly to the above-described embodiment, the DO meter 12, the ORP meter 13, and the pH meter 1 are used.
4. A water temperature gauge 15 and an MLSS meter 16 are provided, and each detection signal is input to the control device 19.

The control device 19 is, for example, a computer having a signal conversion unit for converting each detection signal into a digital signal, a storage unit, and a program. The control device 19 controls each of the cell membrane crushing device 7, the first aeration device 17, and the first return extraction device 5 based on the input value.

The control method is based on the embodiment described above, and is based on the DO value, ORP value, pH value, water temperature, MLSS
And the calculated value of the rate of decrease of the ORP value after non-aeration from the DO value, the value calculated of the rate of decrease of the ORP value after non-aeration as the antecedent variables, and the operation output to the cell membrane crusher 7, The cell membrane crushing device 7, the first aeration device 17, the first return, based on a plurality of fuzzy control rules in which the amount of aeration to the aeration device 17 and the switching instruction to the first return extraction device 5 are consequent variables. The drawing device 5 is controlled.

The fuzzy control rules are based on the above-described embodiment, and the MLSS value of the first biological treatment tank 2 is equal to or more than a predetermined value and the non-aeration processing immediately before the first biological treatment tank 2 is performed. If the DO value decreasing speed is equal to or less than a predetermined value, the first
The sludge is sent from the return extraction device 5 to the cell membrane crushing device 7 and the cell membrane crushing device 7 is operated at the same time, and the MLSS value of the first biological treatment tank 2 is equal to or less than a predetermined value, or the first biological treatment tank 2 When the rate of decrease of the DO value at the time of the non-aeration treatment immediately before is equal to or greater than a predetermined value, or the relative value of the rate of decrease of the ORP value with respect to the rate of decrease of the DO value of the first biological treatment tank 2 is equal to or greater than a predetermined value, The cell membrane crushing operation rule (a) in which the cell membrane crushing device 7 is stopped and the cell is returned from the first return drawing device 5 to the first biological treatment tank 2, and the pH value of the first biological treatment tank 2 is predetermined. When the value is equal to or less than the predetermined value, the amount of aeration of the first aeration device 17 is reduced. When the value is equal to or more than the predetermined value, the amount of aeration is increased, and at the same time, the amount of aeration is relatively changed depending on the water temperature of the first biological treatment tank 2. It is composed of the aeration control rule (b)

Table 4 shows an example in which the above control rules are arranged as fuzzy control rules. In the control rules shown in Table 4, If ~
The and parts of and correspond to the antecedent variables shown in Table 4 of the fuzzy control rule, and the to parts of and correspond to the consequent variables shown in Table 4.

[0074]

[Table 4] (a) If X1 and X2 and X3 Then Y1 (a) If X1 and X2 and X3 Then Y2 (b) If X4 and X5 Then Y3

[0075]

[Table 5] [Antecedent variable] X1 = The DO value decreasing rate during non-aeration processing is equal to or less than a predetermined value. X2 = Relative value of the ORP value decreasing rate to the DO value decreasing rate during non-aeration processing is: X3 = MLSS value is more than a predetermined value X4 = pH value is more than a predetermined value X5 = Relative value of water temperature to pH value is less than a predetermined value

[0076]

[Table 6] [Consequent variables] Y1 = Operation command for cell membrane crushing device Y2 = Switching command of return drawing device Y3 = Aeration amount instruction to first aeration device 17

Here, the above-mentioned [0058] and [005]
As shown in [9], both the antecedent variable and the consequent part are standardized, and the antecedent part consequent part and the consequent part conformity degree are calculated based on the membership function by the min-max centroid method, and each control rule For each control rule, the minimum value (min) of the antecedent part fitness is multiplied by the membership function of the consequent part, and the center of gravity of the membership function synthesized using the maximum value (max) for all control rules is output from the control unit 19. Value.

As described above, the arithmetic processing is performed in the control device 19 based on the control rules in Table 4 constituted by the antecedent variables in Table 5 and the consequent variables in Table 6, and the optimal cell membrane crushing is performed.
Aeration of biological treatment tank and return of sludge. Note that the processing flow in the control device 19 is the same as the processing flow shown in FIG.

[0079]

As described above in detail, according to the first aspect of the present invention, the sludge reduction efficiency is maximized by crushing the cell membrane of the living organisms constituting the surplus sludge and returning it to the biological treatment tank. And maintain the quality of treated water properly.

According to the second aspect of the present invention, similarly to the first aspect of the present invention, the sludge reduction efficiency can be maximized, and the quality of treated water can be appropriately maintained.

According to the third aspect of the present invention, the sludge reduction efficiency can be further maximized, and the quality of the treated water can be further appropriately maintained.

According to the fourth aspect of the present invention, similarly to the first aspect of the present invention, the sludge reduction efficiency is maximized, the quality of the treated water is appropriately maintained, and the organic matter discharged from the cell membrane crushing apparatus is improved. Phosphorus components dissolved in the solution can be removed.

According to the fifth to ninth aspects of the present invention, the operation of the cell membrane crushing apparatus and the return drawing apparatus is controlled by the MLSS value of the biological treatment tank, the DO value decreasing speed in the immediately preceding non-aeration state, and the DO value. By controlling according to the relative value of the ORP value decreasing speed in the immediately preceding non-aeration state or the increasing speed of the MLSS value with respect to the decreasing speed, it becomes possible to operate under the optimal load condition, so that the treated water quality is not deteriorated. Sludge reduction can be implemented. In addition, the operation of the aerator is controlled not only by the DO value of the biological treatment tank but also by the pH value and
By controlling according to the relative value to the H value, it is possible to carry out aeration without excess or deficiency, to secure an optimum activated sludge growth environment, and to treat organic wastewater.

According to the tenth and eleventh aspects of the present invention,
Maximize sludge reduction efficiency and maintain proper treated water quality, and set fuzzy control rules and membership functions based on analysis of characteristics from experimental data or field tests at actual wastewater treatment plants By doing so, it is possible to perform optimal automatic control for 24 hours, and it is possible to significantly reduce maintenance costs. Further, the fuzzy control rules or membership functions can be easily changed, and can be changed on site or remotely, so that maintenance performance can be greatly improved.

According to the twelfth aspect of the present invention, phosphorus is eluted from the crushed sludge or phosphorus dissolved in the supernatant water of the precipitation tank flowing into the discharge section is adsorbed by the phosphorus removing device for efficient phosphorus recovery. To limit the outflow of phosphorus into the treated water.

According to the thirteenth aspect, the cell membrane can be efficiently crushed, and sludge can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a processing flowchart in a control device used in one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Raw water tank 2 ... 1st biological treatment tank 3 ... 1st sedimentation tank 4 ... Discharge part 5 ... 1st return drawing apparatus 6 ... Sludge storage tank 7 ... Cell membrane crushing apparatus 8 ... 2nd biological treatment tank 9 ... Second sedimentation tank 10 ... Second return drawing device 11 ... Phosphorus removal device 12 ... DO meter 13 ... ORP meter 14 ... pH meter 15 ... Water temperature meter 16 ... MLSS meter 17 ... First aerator 18 ... Second Aeration device 19 ... Control device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yutaka Nakamura 3-5-25 Fukae Honcho, Higashinada-ku, Kobe City, Hyogo Prefecture Within Meiken Co., Ltd. (72) Inventor Munetaka Ishikawa 20-2F, Hashimoto Yashita City, Kyoto Prefecture 20-2F Terms (reference) 4D024 AA04 AB12 BA13 BB01 BC01 DA03 DB15 DB20 4D028 BC28 BD11 BD13 BE00 CA09 CA15 CB00 CC05 CC07 CD01 4D059 AA05 BA01 BK11 EA01 EB20

Claims (13)

[Claims] 1. A wastewater containing organic matter is aerated in a first biological treatment tank to decompose organic matter by microorganisms, and after solid-liquid separation in a first sedimentation tank,
The supernatant water separated in the sedimentation tank is disinfected in the discharge part and discharged outside the system, and the sludge deposited at the bottom of the first sedimentation tank is returned to the first biological treatment tank, while the first sludge is returned to the first biological treatment tank. After introducing the sludge from the sedimentation tank into the cell membrane crusher, and crushing the cell membrane of the organisms constituting the sludge by the cell membrane crusher,
An organic wastewater treatment method wherein the organic wastewater is returned to the first biological treatment tank. 2. A wastewater containing organic matter is aerated in a first biological treatment tank to decompose organic matter by microorganisms, and after solid-liquid separation in a first settling tank,
The supernatant water separated in the sedimentation tank is disinfected in the discharge part and discharged outside the system, and the sludge deposited at the bottom of the first sedimentation tank is returned to the first biological treatment tank, while the first sludge is returned to the first biological treatment tank. The sludge from the sedimentation tank is stored in the storage tank, and the sludge from the first sedimentation tank and the sludge from the storage tank are introduced into a cell membrane crusher, and the cell membrane of the organisms constituting the sludge is introduced by the cell membrane crusher. An organic wastewater treatment method comprising crushing and returning the first wastewater to the first biological treatment tank. 3. The organic wastewater treatment method according to claim 1, wherein the sludge whose cell membrane has been crushed by the cell membrane crusher is returned to the second biological treatment tank, and then the sludge is removed from the second biological treatment tank. Sludge is subjected to solid-liquid separation in a second sedimentation tank, and the supernatant water separated in the second sedimentation tank is returned to the first biological treatment tank while the sludge is deposited on the bottom of the second sedimentation tank. An organic wastewater treatment method, comprising returning sludge to a sludge storage tank and / or a cell membrane crusher. 4. The organic wastewater treatment method according to claim 1, wherein the phosphorus component dissolved in the organic solution discharged from the cell membrane crushing device is removed by a phosphorus removing device. . 5. A DO meter is provided in the first biological treatment tank or the second biological treatment tank, and when the DO value decreasing speed in the immediately preceding non-aeration state is equal to or less than a predetermined value, the operation of the cell membrane crushing apparatus is performed. The organic wastewater treatment method according to claim 1, wherein the operation of the cell membrane crusher is stopped when the value is equal to or more than a predetermined value. 6. An ORP meter is provided in the first biological treatment tank or the second biological treatment tank, and an ORP meter is provided for measuring the decrease rate of the ORP value in the immediately preceding non-aeration state with respect to the decreasing rate of the DO value in the immediately preceding non-aeration state. 6. The organic wastewater treatment method according to claim 5, wherein the operation of the cell membrane crusher is stopped when the relative value is equal to or more than a predetermined value. 7. A pH meter is provided in the first biological treatment tank or the second biological treatment tank, and the aeration amount is decreased when the pH value is equal to or less than a predetermined value, and the aeration amount is increased when the pH value is equal to or more than a predetermined value. The organic wastewater treatment method according to claim 5 or 6, wherein: 8. A water temperature gauge is provided in the first biological treatment tank or the second biological treatment tank, and a predetermined value of pH is changed relative to the amount of aeration depending on the water temperature. The organic wastewater treatment method as described in the above. 9. An MLSS meter is provided in the first biological treatment tank or the second biological treatment tank, and when the MLSS value is equal to or more than a predetermined value, the sludge is drawn out to the sludge storage tank, and when the MLSS value is equal to or less than a predetermined value, the first sludge is removed. 9. The organic wastewater treatment method according to claim 5, wherein the organic wastewater is returned to the biological treatment tank or the second biological treatment tank. 10. A biological treatment tank that decomposes wastewater containing organic matter into organic matter by microorganisms, an aeration device that aerates wastewater in the biological treatment tank, a sedimentation tank that separates solid matter decomposed sludge into solid and liquid, A discharge section that disinfects the supernatant water separated in the tank and discharges it to the outside of the system, a return pulling device that pulls out sludge from the sedimentation tank and returns the sludge to the biological treatment tank, and a sludge from the sedimentation tank constitutes the sludge. A cell membrane crushing device for crushing a cell membrane of a living organism and returning sludge to the biological treatment tank, wherein the DO in the biological treatment tank is
Values, the ORP value, the pH value, the water temperature, the MLSS value, the value obtained by calculating the rate of decrease of the DO value, and the value obtained by calculating the rate of decrease of the ORP value, as the antecedent variables, and the operation output to the cell membrane crusher. And a control device that performs a process based on a plurality of fuzzy control rules with aeration amount output to the aeration device and extraction instruction output to the return extraction device as consequent variables,
Meter, the DO meter, the water temperature meter, the ORP meter, and the ML
Inputting each output signal of the SS meter to the control device, and outputting a control signal based on the output signal to the cell membrane crushing device, the aeration device, and the return extraction device based on the fuzzy control rule, Organic wastewater treatment equipment. 11. A biological treatment tank for decomposing wastewater containing organic matter by organic matter using microorganisms, an aeration device for aerating wastewater in the biological treatment tank, a sedimentation tank for solid-liquid separating sludge decomposed by organic matter, and the sedimentation tank. A discharge section that disinfects the supernatant water separated in the tank and discharges it to the outside of the system, a return extraction device that extracts sludge from the sedimentation tank and returns the sludge to the biological treatment tank, and a storage tank that stores the sludge from the sedimentation tank. An organic wastewater treatment apparatus having a cell membrane crushing device for crushing a cell membrane of an organism constituting the sludge and returning the sludge to the biological treatment tank, wherein the DO value, the ORP value, and the pH in the biological treatment tank are provided. Value, water temperature and MLS
The S value, the value obtained by calculating the rate of decrease of the DO value, the value obtained by calculating the rate of decrease of the ORP value, and the value obtained by calculating the rate of increase of the MLSS value are used as the antecedent variables, and the operation output to the cell membrane crushing device is used. And a control device that performs a process based on a plurality of fuzzy control rules with aeration amount output to the aeration device and extraction instruction output to the return extraction device as consequent variables,
Meter, the DO meter, the water temperature meter, the ORP meter, and the ML
Inputting each output signal of the SS meter to the control device, and outputting a control signal based on the output signal to the cell membrane crushing device, the aeration device, and the return extraction device based on the fuzzy control rule, Organic wastewater treatment equipment. 12. A phosphorus removing device is provided on a sludge outflow side or an inflow side of a discharge section of a cell membrane crushing apparatus to remove a phosphorus component dissolved in an organic solution discharged from the cell membrane crushing apparatus. 10. The method according to claim 10, wherein:
2. The organic wastewater treatment device according to 1. 13. The cell membrane crushing apparatus, wherein the cell membrane crushing apparatus uses a bead mill of glass beads, wherein the glass beads contain about 8% to 20% of lithium oxide + sodium oxide + potassium oxide, and Diameter 0.
13. The organic wastewater treatment apparatus according to claim 10, wherein glass beads of 1 mm to 1 mm are contained in 70% or more of the whole, and cell membranes are crushed by the glass beads.