JP6805002B2 - Water treatment control device and water treatment system - Google Patents

Description

The present invention relates to a water treatment control device and a water treatment system that control a water treatment device using activated sludge.

At sewage treatment plants, sewage is generally treated by the following procedure. First, after removing solids in the sand basin and first settling basin, oxygen is supplied to microorganisms (activated sludge) by aeration in a biological reaction tank to remove organic matter, nitrogen, and phosphorus in the sewage. After that, the activated sludge is settled and separated in the final settling basin, and the supernatant water is discharged to the public water area as effluent water. Activated sludge settled and separated in the final settling basin is returned to the biological reaction tank and used again for sewage treatment.
In a combined sewer system that consolidates sewage and rainwater into a treatment plant with the same pipe, inflow sewage that exceeds the maximum planned sewage amount is generally treated by first removing solids in the settling basin and then disinfecting it. After that, it is released into public water areas. Since the conventional biological treatment is not performed in the simple treatment, it is desirable to reduce the simple treatment amount and increase the biological treatment amount in order to reduce the environmental load on the discharge destination.

On the other hand, when the amount of biological treatment, that is, the inflow rate to the biological reaction tank is increased, the residence time in the final settling basin is shortened, the gravity sedimentation of activated sludge becomes insufficient, and the activated sludge can flow out into the discharged water. There is sex. The outflow of activated sludge causes an increase in the environmental load on public water bodies and a subsequent deterioration in treatment function.

In order to deal with such a problem, for example, a technique described in Patent Document 1 has been proposed. In Patent Document 1, when the raw water flowing into the aerobic biological treatment tank exceeds 50% of the design treatment flow rate of the biological treatment tank at the time of flooding, the last biological treatment tank among the biological treatment tanks connected in series By reducing the amount of aeration so that the dissolved oxygen concentration of the water is 0.1 mg / L or more and 0.4 mg / L or less, the amount of activated sludge that flows out from the biological treatment tank to the final settling basin is suppressed and flows out from the final settling basin. A configuration that makes it possible to accelerate the recovery of the water quality of the treated water (supernatant water) is disclosed.

Japanese Patent No. 5315118

However, in the configuration described in Patent Document 1, since the aeration air volume is adjusted so that the dissolved oxygen concentration in the aerobic tank is within a predetermined range, the degree of settling of activated sludge in the aerobic tank can be determined. It is difficult to grasp accurately. Therefore, in the adjustment of the aeration air volume based on the dissolved oxygen concentration, the settling of the activated sludge in the aerobic tank is smaller than expected, and the activated sludge may flow out into the discharged water.
Therefore, the present invention is a water treatment control device capable of suppressing the outflow of activated sludge while ensuring the maximum amount of biological treatment even when the inflow flow rate of sewage (water to be treated) suddenly increases. And provide a water treatment system.

In order to solve the above problems, the water treatment control device according to the present invention includes at least a reaction tank that first treats the water to be treated flowing from the settling pond through the first connection pipe with activated sludge, and a first reaction tank from the reaction tank. 2 To discharge the activated sludge contained in the supernatant liquid flowing in through the connecting pipe into the final settling pond and the water to be treated that branches from the first connecting pipe and flows in from the first settling pond as simple treated water. A water treatment control device that controls a water treatment device having a bypass pipe and a flow rate adjusting valve installed on the first connection pipe on the downstream side of the branch portion of the bypass pipe, and is measured by an MLSS meter. A flow rate upper limit value calculation unit that calculates the flow rate upper limit value of the water to be treated flowing into the reaction tank based on the activated sludge concentration measurement value in the reaction tank, and the flow rate adjusting valve so as not to exceed the flow rate upper limit value. It is characterized by including a flow control valve opening degree control unit for controlling the opening degree of the above.
Further, the water treatment system according to the present invention includes (1) at least a reaction tank for treating the water to be treated that first flows from the settling pond through the first connection pipe with activated sludge, and a second connection pipe from the reaction tank. A final settling pond that setstles and separates activated sludge contained in the supernatant liquid that flows in through the water, and a bypass pipe that branches from the first connection pipe and discharges the water to be treated that flows in from the first settling pond as simple treated water. A water treatment device having a flow control valve which is downstream from the branch portion of the bypass pipe and is installed in the first connection pipe, and (2) is installed in the first connection pipe and flows into the reaction tank. Based on the flow meter that measures the flow rate of the water to be treated, (3) the MLSS meter that measures the activated sludge concentration in the reaction vessel, and (4) the activated sludge concentration measurement value measured by the MLSS meter. It has a flow rate upper limit value calculation unit that calculates the flow rate upper limit value of the water to be treated flowing into the reaction tank, and a flow rate adjustment valve opening control unit that controls the opening degree of the flow rate adjustment valve so as not to exceed the flow rate upper limit value. It is characterized by including a water treatment control device.

According to the present invention, a water treatment control device capable of suppressing the outflow of activated sludge while ensuring the maximum amount of biological treatment even when the inflow flow rate of sewage (water to be treated) suddenly increases. And it becomes possible to provide a water treatment system.
Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is a schematic whole block diagram of the water treatment system of Example 1 which concerns on one Example of this invention. It is a functional block diagram of the water treatment control device shown in FIG. It is a sludge settling model of activated sludge, and is a conceptual diagram showing the relationship between the activated sludge concentration of treated water and the inflow load of activated sludge into the final settling basin. It is a modification of the water treatment apparatus shown in FIG. 1, and is a schematic overall configuration diagram of the water treatment system. It is a schematic overall block diagram of the water treatment system of Example 2 which concerns on another Example of this invention. It is a functional block diagram of the water treatment control device shown in FIG.

Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic overall configuration diagram of the water treatment system of Example 1 according to an embodiment of the present invention. In FIG. 1, the solid line shows the piping and the dotted line shows the signal line. The water treatment system 1 according to the present embodiment is a water treatment device 2 for removing organic substances and the like by using activated sludge in the standard activated sludge method for sewage (treated water) such as domestic wastewater or industrial wastewater, and water. A processing control device 3 is provided.

(Configuration of water treatment equipment)
As shown in FIG. 1, the water treatment apparatus 2 includes a first settling basin 4, an aerobic tank (reaction tank) 5, and a final settling basin 6 in this order from the inflow side of the sewage to be treated. As shown in FIG. 1, the aerobic tank (reaction tank) 5 is provided in four stages or in series with four tanks, and the aerobic tank (reaction tank) 5 on the most downstream side (final stage) has a total of 12 MLSSs. is set up. In the following, a case where four aerobic tanks (reaction tanks) 5 are provided in series is shown as an example, but the number of tanks is not limited to this and is appropriately set.

The MLSS total 12 installed in the aerobic tank (reaction tank) 5 on the most downstream side is a mixed liquor suspended solid (MLSS) in the aerobic tank (reaction tank) 5, that is, aerobic. This is a measuring device for measuring the amount of activated sludge (unit: mg / L) in the tank (reaction tank) 5 as the MLSS concentration.

For example, sewage, which is water to be treated, flows into the first sedimentation basin 4 from a sand basin (not shown) through an inflow pipe 15, and solids contained in the sewage (water to be treated) settle in the first sedimentation basin 4 by gravity. Is settled and separated by. When the flow rate of the first settling basin 4 increases, such as in rainy weather, the simple treated water after the simple treatment is transferred to the bypass pipe 19 without passing through the aerobic tank (reaction tank) 5, and the first sedimentation occurs. A part of the runoff from the pond 4 is discharged to the outside of the system. Here, the simple treated water is a part of the outflow water after the solid content in the inflow sewage (treated water) is removed by gravity sedimentation by the sand basin (not shown) and the first sedimentation basin 4. As shown in FIG. 1, the bypass pipe 19 is branched from the first connection pipe 16 that connects the first settling basin 4 and the aerobic tank (reaction tank) 5 on the most upstream side (first stage). A flow rate adjusting valve 9 and a flow meter 11 are installed in the first connection pipe 16 on the downstream side of the branch portion of the bypass pipe 19. The flow meter 11 measures the flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage).
In addition, sewage (treated water), which is the supernatant liquid from the first settling basin 4, flows into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) via the first connection pipe 16 and is returned. Return sludge (activated sludge 20) flows in from the final settling basin 6 through the return sludge pipe 21 in which the pump 10 is installed, and nitrifying bacteria in the activated sludge change ammonia nitrogen (NH _4- N) into nitrate nitrogen. Nitrification is performed to oxidize to (NO _3- N). In addition, organic matter is oxidized by aerobic heterotrophic bacteria.
The final settling basin 6 uses sewage, which is the water to be treated after biological treatment, that flows in from the aerobic tank (reaction tank) 5 on the most downstream side (final stage) via the second connection pipe 17, as a supernatant and activated sludge. It is a facility that settles and separates to 20 by gravity sedimentation. The supernatant liquid after sedimentation separation is discharged to the outside of the system by the outflow pipe 18 as treated water.

As shown in FIG. 1, the plurality of air diffusers 7 provided in the aerobic tank (reaction tank) 5 are connected to the blower 8 via the air diffuser pipe 22, and air is introduced into the aerobic tank (reaction tank) 5. Be supplied.
The flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) measured by the flow meter 11, that is, the inflow sewage flow rate measurement value is water treated via a signal line. It is output to the control device 3. Further, the MLSS concentration measurement value measured by the MLSS total 12 installed in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) is output to the water treatment control device 3 via the signal line.

(Water treatment control device)
FIG. 2 is a functional block diagram of the water treatment control device 3 in FIG. As shown in FIG. 2, the water treatment control device 3 includes an activated sludge concentration estimation unit 31, a flow rate upper limit value calculation unit 32, a flow rate adjustment valve opening control unit 33, a measurement value acquisition unit 34, and at least preset treated water. The storage unit 35, the communication I / F36, the input I / F37, and the output I / F38 for storing information including the activated sludge concentration upper limit value and the sludge sedimentation model of the activated sludge as a sludge outflow concentration estimation function described later. They are connected to each other via an internal bus 41. Further, the input I / F 37 is connected to the input unit 38, and takes in the upper limit value of the activated sludge concentration of the treated water discharged through the outflow pipe 18 input via the input unit 38 and various set values. The output I / F 38 is connected to the display unit 40, and the display unit 40 displays, for example, various set values, the upper limit value of the flow rate of the sewage flowing into the aerobic tank (reaction tank) 5, and the predicted value of the sludge concentration of the treated water. Etc. are displayed on the screen.

The measurement value acquisition unit 34 uses the communication I / F 36 to obtain the inflow sewage flow rate measurement value, which is the measurement value of the sewage flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage), which is measured by the flow meter 11. And acquired via the internal bus 41. Further, the measurement value acquisition unit 34 uses the communication I / F 36 and the internal bus 41 to transfer the MLSS concentration measurement value in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) measured by the MLSS total 12. Get through. The measured value acquisition unit 34 performs processing such as noise removal on the acquired inflow sewage flow rate measurement value and MLSS concentration measurement value, and performs an activated sludge concentration estimation unit 31 and a flow rate upper limit value calculation unit via the internal bus 41. It is transferred to 32 and stored in a predetermined storage area of the storage unit 35. In FIG. 2, the measured values from the flow meter 11 and the MLSS meter 12 are shown as signal wiring superimposed on one signal line, but this is shown in this way for convenience of drawing. Actually, the signal wiring is input in parallel to the communication I / F 36 via the signal line provided for each measuring instrument.

The activated sludge concentration estimation unit 31 is the inflow sewage flow rate measurement value of the sewage flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) transferred from the measurement value acquisition unit 34 and the most downstream side (final stage). Based on the measured value of MLSS concentration in the aerobic tank (reaction tank) 5, the activated sludge concentration of the treated water discharged through the outflow pipe 18 is determined by using the sludge sedimentation model of the activated sludge stored in the storage unit 35. Predict.

The flow rate upper limit value calculation unit 32 is a process in which the activated sludge concentration predicted value of the treated water estimated by the activated sludge concentration estimation unit 31 is input in advance via the input unit 38 and stored in a predetermined storage area of the storage unit 35. The maximum value of the flow rate of sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) that does not exceed the upper limit of the activated sludge concentration of water is calculated as the upper limit of the flow rate. The flow rate upper limit value calculation unit 32 stores the calculated flow rate upper limit value as a set value in a predetermined storage area of the storage unit 35 via the internal bus 41.

In the flow rate adjusting valve opening degree control unit 33, the inflow sewage flow rate measurement value, which is the measurement value of the sewage flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage), is calculated by the flow rate upper limit value calculation unit 32. The opening degree of the flow rate adjusting valve 9 is obtained so as not to exceed the upper limit value of the flow rate, and the opening command value is output to the flow rate adjusting valve 9 via the internal bus 41 and the output I / F 38. Control the opening of.

These active sludge concentration estimation unit 31, flow rate upper limit value calculation unit 32, flow rate adjustment valve opening control unit 33, and measurement value acquisition unit 34 are, for example, a processor such as a CPU (not shown), a ROM for storing various programs, and an operation. It is realized by a storage device such as a RAM or an external storage device that temporarily stores process data, and a processor such as a CPU reads and executes various programs stored in the ROM, and the calculation result that is the execution result is stored in the RAM. Or store it in an external storage device. Here, the calculation result or the data of the calculation process may be stored in the storage unit 35 instead of the RAM.

Here, an outline of a method for calculating the upper limit value of the flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 using the settling model of activated sludge by the flow rate upper limit value calculation unit 32 will be described.
FIG. 3 is a sludge settling model of activated sludge, and is a conceptual diagram showing the relationship between the activated sludge concentration of treated water and the inflow load of activated sludge into the final settling basin. The horizontal axis represents the activated sludge inflow load into the final sedimentation basin 6, the vertical axis represents the activated sludge concentration of the treated water, and the sludge sedimentation model of the activated sludge represented as a graph showing the correlation between them is stored in the storage unit 35. Has been done. The load of activated sludge inflow to the final settling basin 6 on the horizontal axis is the flow rate of sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) and the most downstream side (final). It is the product of the MLSS concentration in the aerobic tank (reaction tank) 5 of the stage). If the flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage), that is, the flow rate of the inflow water to the final settling basin 6, is large, the settling time becomes short. On the other hand, if the MLSS concentration in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) is high, long-term gravity sedimentation is required to obtain a sufficiently low activated sludge concentration as treated water. As described above, in the activated sludge settling model shown in FIG. 3, the activated sludge concentration of the treated water increases as the active sludge inflow load into the final settling basin 6 increases. In FIG. 3, when a preset upper limit value of the activated sludge concentration of the treated water is input to the sludge sedimentation model of the activated sludge, the upper limit value of the activated sludge inflow load into the final sedimentation basin 6 is obtained. Then, the flow rate upper limit value calculation unit 32 transfers the upper limit value of the activated sludge inflow load to the obtained final settling basin 6 from the measurement value acquisition unit 34 to the most downstream side (final stage) aerobic tank (reaction). The upper limit of the flow rate, which is the maximum flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) by dividing by the MLSS concentration measurement value in the tank) 5. Is calculated.

In addition, the activated sludge concentration estimation unit 31 is used to measure the inflow sewage flow rate of the sewage flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) transferred from the measurement value acquisition unit 34 and the most downstream side (first stage). The product of the measured value of the MLSS concentration in the aerobic tank (reaction tank) 5 of the final stage) was obtained to obtain the activated sludge inflow load into the final sedimentation pond 6, and the activated sludge sedimentation model shown in FIG. 3 was used. By obtaining the activated sludge concentration of the corresponding treated water, the activated sludge concentration predicted value of the treated water discharged through the outflow pipe 18 is obtained.

In this embodiment, the sludge settling model of activated sludge is used to predict the outflow status of activated sludge into the treated water, and the allowable sewage (reaction tank) 5 on the most upstream side (first stage) flows into the aerobic tank (reaction tank). Calculate the upper limit of the flow rate of water to be treated) and use it as the set value. As a result, in order to reduce the discharge flow rate of the simple treated water, it is possible to reduce the risk of the outflow of activated sludge, which is a concern when the inflow amount to the aerobic tank (reaction tank) 5 on the most upstream side (first stage) is increased.

In this embodiment, the water treatment apparatus 2 to which the standard activated sludge method is introduced is assumed. However, for example, the activated sludge is provided with the final settling basin 6 such as the anaerobic aerobic activated sludge method and the circulating nitrification denitrification method. If it is a processing method using, the same can be applied.
Further, in this embodiment, in the sludge sedimentation model of activated sludge, the MLSS concentration in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) is calculated in order to calculate the inflow load of activated sludge into the final sedimentation basin 6. As a value to be multiplied by, only the flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) is used, but the value is not limited to this. For example, the flow rate of the returned sludge may be added to the flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage). In this case, the upper limit of the total value of the flow rate of the sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) and the flow rate of the returned sludge is set, and the uppermost value is set. ), At least one of the flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 and the flow rate of the returned sludge may be controlled. It is also applicable to a treatment method in which a part of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) flows into the middle stage of the aerobic tank 5. The flow rate of sewage (water to be treated) is the sum of the inflow rate to the aerobic tank (reaction tank) 5 on the most upstream side (first stage) and the inflow flow rate to the middle stage of the aerobic tank (reaction tank) 5. ..

In this embodiment, the sludge settling model of activated sludge is defined as a function for predicting the activated sludge concentration of treated water from the inflow load of activated sludge into the final settling basin 6, but the present invention is not limited to this. .. For example, for each MLSS concentration in the aerobic tank (reaction tank) 5, it is active as a function expressing the relationship between the flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 and the activated sludge concentration of the treated water. A sludge sedimentation model of sludge may be defined.
Further, it may be used as a sludge sedimentation model of activated sludge in consideration of factors affecting the sedimentation property of activated sludge in the final sedimentation basin 6, such as water temperature, sedimentation index of activated sludge, and flow rate of returned sludge. For example, a sludge settling model of activated sludge may be defined as a function representing the relationship between the inflow load of activated sludge into the final settling basin 6 and the activated sludge concentration of the treated water for each water temperature in an arbitrary range. In addition, the flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 and the MLSS concentration in the aerobic tank (reaction tank) 5 to be input to the sludge sedimentation model of these activated sludges are determined for each control cycle. In addition to the value of, a value in an arbitrary period such as a period in consideration of the residence time in the final settling basin 6 may be used. For example, in consideration of the transfer in the flow direction in the final settling basin 6, the activated sludge settling model of the activated sludge simulating the behavior of the activated sludge from the inflow part to the outflow part of the final settling basin 6 is used. The concentration may be predicted.

In this embodiment, in the flow rate upper limit value calculation unit 32 constituting the water treatment control device 3, the sludge settling model of activated sludge is used to flow into the aerobic tank (reaction tank) 5 on the most upstream side (first stage). The upper limit of the flow rate of the sewage (water to be treated) was calculated, but as the flow rate of the sewage (water to be treated) increased, the MLSS concentration in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) increased. It will decrease. Therefore, when the lower limit of the MLSS concentration in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) is set, the aerobic tank (reaction tank) on the most upstream side (first stage) is set for each control cycle. Based on the flow rate of the sewage (water to be treated) flowing into 5, the MLSS concentration in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) is predicted, and the uppermost flow so as not to fall below the lower limit of the MLSS concentration. The upper limit of the flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the side (first stage) may be calculated. In this case, it is desirable to set the smaller of the calculation results of the two methods as the flow rate upper limit value.

Next, a modified example of the water treatment apparatus 2 shown in FIG. 1 will be described. FIG. 4 is a modification of the water treatment device 2 shown in FIG. 1, and is a schematic overall configuration diagram of the water treatment system 1a. As shown in FIG. 4, in the water treatment device 2a, in addition to the configuration of the water treatment device 2 described above, an SS total 13 is installed in the outflow pipe 18 as a sludge outflow concentration measuring unit downstream of the final settling basin 6. .. The SS total 13 installed in the outflow pipe 18 is a suspended solid or suspended solid (SS) in the treated water flowing through the outflow pipe 18, that is, the amount of activated sludge in the treated water flowing through the outflow pipe 18. It is a measuring device for measuring (unit: mg / L) as an activated sludge concentration. The measured value of the activated sludge concentration in the treated water flowing through the outflow pipe 18 measured by the SS meter 13 is output to the water treatment control device 3 via the signal line.
Here, a method of utilizing the measured values of the SS total 13 in the sludge sedimentation model of activated sludge will be described. The sludge settling model of activated sludge stored in the storage unit 35 (FIG. 2) constituting the water treatment control device 3 described above is configured to use a model formula constructed in advance or based on a theoretical formula. However, the properties of activated sludge are considered to fluctuate depending on the season. Therefore, the flow measurement value (measured value of the inflow sewage flow rate) of the sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) by the flow meter 11 and the most downstream side (measured value of the inflow sewage flow rate) by the MLSS total 12 ( A model formula was constructed based on the data for the past predetermined period regarding the relationship between the MLSS concentration measurement value in the aerobic tank (reaction tank) 5 in the final stage) and the activated sludge concentration measurement value of the treated water by the SS total 13. By going on, it is possible to follow changes in the properties of activated sludge.

In the water treatment system 1a, by using a sludge sedimentation model of activated sludge based on an actually measured value of the activated sludge concentration of treated water, it is possible to cope with changes in the properties of activated sludge and suppress the outflow of activated sludge. In the example shown in FIG. 4, the SS total 13 is installed in the outflow pipe 18 downstream of the final settling basin 6, but the present invention is not necessarily limited to this. The SS total 13 may be installed in any place where the activated sludge concentration of the treated water can be measured, and may be installed in the final settling basin 6, for example.
Although the SS total 13 is used as the sludge outflow concentration measuring unit, instead of this, the activated sludge concentration of the treated water can be estimated by a turbidity meter, a UV meter, a sludge interface meter, or an imaging analysis. If so, it can be used as a sludge runoff concentration measuring unit.
Using the sludge settling model of activated sludge, the upper limit of the flow rate of sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) was set, but the activated sludge by SS total 13 was set. When the measured concentration value exceeds the upper limit of the activated sludge concentration of the treated water, the opening of the flow control valve 9 is controlled by feedback so that the measured value of the activated sludge concentration by the SS total 13 falls below the upper limit of the activated sludge concentration of the treated water. It may be configured to control.

As described above, according to the present embodiment, even when the inflow flow rate of sewage (water to be treated) suddenly increases, the outflow of activated sludge is suppressed while ensuring the maximum amount of biological treatment. It becomes possible to provide a water treatment control device and a water treatment system to be obtained.

Further, according to this embodiment, the water treatment control device predicts the outflow status of the activated sludge into the treated water using the sludge settling model of the activated sludge, and the allowable sewage flowing into the aerobic tank (reaction tank). By calculating the upper limit of the flow rate of (water to be treated) and setting it as the set value, the activity that is a concern when the inflow to the aerobic tank (reaction tank) is increased in order to reduce the discharge flow of the simple treated water. The risk of sludge outflow can be reduced.

FIG. 5 is a schematic overall configuration diagram of the water treatment system of the second embodiment according to another embodiment of the present invention, and FIG. 6 is a functional block diagram of the water treatment control device shown in FIG. In the first embodiment described above, the water treatment control device 3 sets the upper limit of the flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 by using the sludge sedimentation model of activated sludge. .. On the other hand, in this embodiment, in addition to the configuration of Example 1, the flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 and the MLSS concentration in the aerobic tank (reaction tank) 5 are adjusted. Based on this, the configuration was implemented to control the flow rate of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 so as to maximize the amount of pollutants removed in the aerobic tank (reaction tank) 5. Different from Example 1. The same components as in the first embodiment are designated by the same reference numerals, and the description overlapping with the first embodiment will be omitted below.

As shown in FIG. 5, the water treatment system 1b according to the present embodiment includes a water treatment device 2b and a water treatment control device 3a.
The water treatment device 2b includes a BOD meter 14 in addition to the flow rate adjusting valve 9 and the flow meter 11 installed in the first connection pipe 16 on the downstream side of the branch portion of the bypass pipe 19. The BOD total 14 is a biochemical oxygen demand amount (biochemical oxygen demand) due to organic substances contained in sewage (treated water) that flows through the first connection pipe 16 and flows into the aerobic tank (reaction tank) 5 on the most upstream side (first stage). Biochemical Oxygen Demand (BOD), that is, the amount of organic matter (unit: mg / L) easily decomposed by microorganisms contained in the sewage (water to be treated) flowing through the first connection pipe 16 is used as the organic matter (BOD) concentration. It is a measuring device for measuring. In other words, the BOD total 14 functions as an inflow water quality estimation unit that estimates the water quality of the sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage). The measured organic substance (BOD) concentration of the sewage (treated water) that flows through the first connection pipe 16 and flows into the aerobic tank (reaction tank) 5 on the most upstream side (first stage), which is measured by the BOD meter 14, is , The inflow sewage flow rate measurement value measured by the flow meter 11 and the MLSS concentration measurement value measured by the MLSS meter 12 are output to the water treatment control device 3a via the signal line.

As shown in FIG. 6, the water treatment control device 3a further includes a removal amount estimation unit 42 in addition to the configuration of the water treatment control device 3 shown in FIG. 2 in the above-described first embodiment. The removal amount estimation unit 42 is similar to the above-mentioned active sludge concentration estimation unit 31, flow rate upper limit value calculation unit 32, flow rate adjustment valve opening control unit 33, and measurement value acquisition unit 34, for example, a processor such as a CPU (not shown). , A ROM that stores various programs, a RAM that temporarily stores data in the calculation process, a storage device such as an external storage device, and a processor such as a CPU that reads and executes various programs stored in the ROM. , The calculation result which is the execution result is stored in the RAM or the external storage device. Here, the calculation result or the data of the calculation process may be stored in the storage unit 35 instead of the RAM.

Inflow of sewage flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) measured by the flow meter 11 The measured value of the inflow of sewage, measured by the BOD meter 14, passes through the first connection pipe 16 and reaches the maximum. Organic substance (BOD) concentration measurement value of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the upstream side (first stage), and the most downstream side (final stage) measured by the MLSS total 12 The MLSS concentration measurement value in the air tank (reaction tank) 5 is transferred to the removal amount estimation unit 12 via the measurement value acquisition unit 34.
Further, the storage unit 35 stores at least a preset upper limit value of the activated sludge concentration of the treated water, a sludge sedimentation model of the activated sludge as the above-mentioned sludge outflow concentration estimation function, and a reaction model of the activated sludge. .. In the reaction model of activated sludge, basically, as shown in the following equation (1), the product of the reaction rate of activated sludge, the amount of microorganisms, and the treatment time for each control cycle is integrated to form an aerobic tank (aerobic tank (1). The amount of organic matter removed by the reaction tank) 5 is calculated.
Removal amount = reaction rate x amount of microorganisms x processing time ... (1)
In formula (1), the amount of microorganisms is a function of the MLSS concentration in the aerobic tank (reaction tank) 5 on the most downstream side (final stage), and the treatment time is the aerobic tank (reaction tank) on the most upstream side (first stage). ) It is a function of the flow rate of the sewage (water to be treated) flowing into 5. In the formula (1), the removal amount is large if the MLSS concentration in the aerobic tank (reaction tank) 5 on the most downstream side (final stage) is large, and goes to the aerobic tank (reaction tank) 5 on the most upstream side (first stage). The larger the flow rate of the inflowing sewage (water to be treated), the smaller the flow rate.
The removal amount estimation unit 12 passes through the flow rate of sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) (measured value of the inflow sewage flow rate) and the first connection pipe 16. Measured organic substance (BOD) concentration of sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the upstream side (first stage), and the aerobic tank (reaction tank) 5 on the most downstream side (final stage). By inputting the measured value of MLSS concentration in the MLSS concentration into the reaction model of activated sludge stored in the storage unit 35, the amount of organic substances removed is estimated and the amount of organic substances removed is maximized on the most upstream side (first stage). ), The flow rate (maximized flow rate) of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 is calculated.

The flow control valve opening degree control unit 33 receives sewage (treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) that maximizes the removal amount of organic substances calculated by the removal amount estimation unit 12. Water) flow rate (maximized flow rate) and the upper limit of the flow rate based on the activated sludge concentration predicted value of the treated water estimated by the activated sludge concentration estimation unit 31 using the activated sludge sedimentation model described above in Example 1. The upper limit of the flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) calculated by the value calculation unit 32 is compared. As a result of comparison, when the maximized flow rate exceeds the flow rate upper limit value, the flow rate adjusting valve opening control unit 33 shifts the flow rate upper limit value to the aerobic tank (reaction tank) 5 on the most upstream side (first stage). Set as the flow rate set value of the inflowing sewage (water to be treated), obtain the opening degree of the flow rate adjusting valve 9 so that the inflow sewage flow rate measurement value by the flow meter 11 becomes the flow rate set value, and use the internal bus as the opening command value. It outputs to the flow rate adjusting valve 9 via 41 and the output I / F 38. On the other hand, as a result of comparison, when the maximized flow rate does not exceed the upper limit of the flow rate, the flow rate adjusting valve opening control unit 33 sets the maximized flow rate to the aerobic tank (reaction tank) on the most upstream side (first stage). Set as the flow rate set value of the sewage (water to be treated) flowing into 5, and obtain the opening degree of the flow rate adjusting valve 9 and use it as the opening command value so that the flow rate measurement value of the inflow sewage flow rate by the flow meter 11 becomes the flow rate set value. It outputs to the flow rate adjusting valve 9 via the internal bus 41 and the output I / F 38.

In this embodiment, the BOD meter 14 installed in the first connection pipe 16 is used as the water quality meter, and the sewage (treated water) flowing into the aerobic tank (reaction tank) 5 on the most upstream side (first stage) is used. ) Was configured to measure the organic matter (BOD) concentration, but instead of this, a measuring device for other items related to organic matter such as COD (Chemical Oxygen Demand), an SS meter that can estimate the organic matter concentration, a UV meter, etc. 1 It may be configured to be installed in the connection pipe 16. Further, a measuring device for items other than organic substances may be used, and for example, a measuring device for nitrogen and phosphorus may be installed in one connection pipe 16.

As described above, according to the present embodiment, in addition to the effect of the first embodiment, the activated sludge from the final settling basin 6 is controlled by controlling the flow rate of the sewage (water to be treated) flowing into the aerobic tank (reaction tank) 5. It is possible to suppress the outflow and maximize the amount of organic matter removed in the aerobic tank (reaction tank) 5, which can greatly contribute to the reduction of the environmental load on public water areas.

The present invention is not limited to the above-mentioned examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations.

1,1a, 1b ... Water treatment system 2,2a, 2b ... Water treatment device 3,3a ... Water treatment control device 4 ... First settling basin 5 ... Aerobic tank (reaction tank)
6 ... Final settling basin 7 ... Air diffuser 8 ... Blower 9 ... Flow control valve 10 ... Return pump 11 ... Flow meter 12 ... MLSS total 13 ... SS meter 14 ... BOD total 15 ... Inflow pipe 16 ... First connection pipe 17 ... Second connection pipe 18 ... Outflow pipe 19 ... Bypass pipe 20 ... Active sludge 21 ... Return sludge piping 22 ... Air diffuser piping 31 ... Active sludge concentration estimation unit 32 ... Flow limit value calculation unit 33 ... Flow control valve opening control unit 34 ... Measurement value acquisition unit 35 ...・ Storage unit 36 ・ ・ ・ Communication I / F
37 ... Input I / F
38 ... Output I / F
39 ... Input unit 40 ... Display unit 41 ... Internal bus 42 ... Removal amount estimation unit

Claims (10)

At least, the reaction tank that treats the water to be treated that flows in from the first settling basin through the first connection pipe with activated sludge and the activated sludge contained in the supernatant liquid that flows in from the reaction tank through the second connection pipe are settled. The final settling basin to be separated, the bypass pipe for discharging the water to be treated that branches from the first connection pipe and flows in from the first settling basin as simple treated water, and the first settling basin downstream from the branch portion of the bypass pipe. A flow control valve installed in 1 connection pipe, a flow meter installed in the 1st connection pipe to measure the flow rate of water to be treated flowing into the reaction tank, and an activated sludge concentration in the reaction tank are measured. A water treatment control device that controls a water treatment device having an MLSS meter .
The inflow load of active sludge into the final settling pond, which is the product of the flow rate of the water to be treated flowing into the reaction tank and the activated sludge concentration in the reaction tank, and the activated sludge concentration of the treated water flowing out of the final settling pond. The sludge sedimentation model of active sludge that defines the correlation with, or the flow rate of water to be treated flowing into the reaction vessel and the activated sludge concentration of treated water flowing out from the final sedimentation pond for each active sludge concentration in the reaction vessel. Using the activated sludge sedimentation model defined as a function representing the relationship with, the activated sludge concentration upper limit value of the treated water set in advance and the activated sludge concentration measured value in the reaction tank measured by the MLSS meter are used. Based on this, the maximum value of the flow rate of the water to be treated flowing into the reaction tank is calculated as the upper limit of the flow rate of the water to be treated flowing into the reaction tank within the range not exceeding the preset activated sludge concentration upper limit value. Flow rate upper limit value calculation unit and
A water treatment control device including a flow rate adjusting valve opening degree control unit that controls the opening degree of the flow rate adjusting valve so as not to exceed the flow rate upper limit value. In the water treatment control device according to claim 1,
Activated sludge measured by the MLSS meter using a sludge settling model of activated sludge that defines the correlation between the inflow load of activated sludge into the final settling pond and the activated sludge concentration of the treated water flowing out of the final settling pond. based on the flow rate of the for-treatment water flowing into the reactor as measured by the density measurement and the flowmeter, the activated sludge concentration estimator to predict the activated sludge concentration in the treated water flowing out to the outlet pipe from the settling tank A water treatment control device characterized by having. In the water treatment control device according to claim 1 ,
When the activated sludge concentration of the treated water measured by the SS meter exceeds the preset activated sludge concentration upper limit value of the treated water, the flow rate adjusting valve opening control unit determines the treated water measured by the SS meter. A water treatment control device characterized in that the opening degree of the flow rate adjusting valve is controlled by feedback control so that the activated sludge concentration does not exceed the activated sludge concentration upper limit value of the treated water. In the water treatment control device according to claim 1 ,
The water quality estimation value of the water to be treated flowing into the reaction tank by the inflow water quality estimation unit installed in the first connection pipe, the activated sludge concentration measurement value measured by the MLSS meter, and the flow meter are measured. A removal amount estimation unit for estimating the removal amount of organic substances by the reaction tank based on the flow rate of the water to be treated flowing into the reaction tank is provided.
The flow rate adjusting valve opening degree control unit removes organic substances by the reaction tank estimated by the flow rate upper limit value of the water to be treated or the removal amount estimation unit calculated by the flow rate upper limit value calculation unit. A water treatment control device characterized in that the opening degree of the flow rate adjusting valve is controlled based on the amount. In the water treatment control device according to claim 4 .
The removal amount estimation unit calculates the maximum flow rate of the water to be treated flowing into the reaction tank, which maximizes the amount of organic matter removed by the reaction tank.
The flow rate adjusting valve opening degree control unit compares the maximized flow rate calculated by the removal amount estimation unit with the flow rate upper limit value of the water to be treated flowing into the reaction tank calculated by the flow rate upper limit value calculation unit. A water treatment control device, wherein any one of the small values is set as a flow rate setting value, and the opening degree of the flow rate adjusting valve is controlled. At least, the reaction tank that treats the water to be treated that flows in from the first settling basin through the first connection pipe with active sludge and the active sludge contained in the supernatant liquid that flows in from the reaction tank through the second connection pipe are settled. The final settling basin to be separated, a bypass pipe for discharging the water to be treated that branches from the first connection pipe and flows in from the first settling basin as simple treated water, and the first settling basin downstream from the branch of the bypass pipe. A flow control valve installed in 1 connection pipe, a flow meter installed in the 1st connection pipe to measure the flow rate of water to be treated flowing into the reaction tank, and an active sludge concentration in the reaction tank are measured. A water treatment device with an MLSS meter and
The inflow load of active sludge into the final settling pond, which is the product of the flow rate of the water to be treated flowing into the reaction tank and the concentration of active sludge in the reaction tank, and the active sludge concentration of the treated water flowing out of the final settling pond. A sludge settling model of active sludge that defines the correlation with, or the flow rate of water to be treated flowing into the reaction tank and the active sludge concentration of treated water flowing out from the final settling pond for each active sludge concentration in the reaction tank. using sludge sedimentation model of activated sludge was defined as a function representing the relationship between, on the basis of the preset activated sludge concentration limit of treated water and the MLSS activated sludge concentration measuring values measured by meter, the preset Calculation of the upper limit of the flow rate, which is calculated by setting the maximum flow rate of the water to be treated flowing into the reaction tank as the upper limit of the flow rate of the water to be treated flowing into the reaction tank within the range not exceeding the upper limit of the active sludge concentration of the treated water. A water treatment system comprising a unit and a water treatment control device having a flow rate adjusting valve opening degree control unit that controls the opening degree of the flow rate adjusting valve so as not to exceed the flow rate upper limit value. In the water treatment system according to claim 6 ,
The water treatment control device is
Activated sludge measured by the MLSS meter using a sludge settling model of activated sludge that defines the correlation between the inflow load of activated sludge into the final settling pond and the activated sludge concentration of the treated water flowing out of the final settling pond. An activated sludge concentration estimation unit that predicts the activated sludge concentration of the treated water flowing out from the final settling pond to the outflow pipe based on the concentration measurement value and the flow rate of the water to be treated flowing into the reaction tank measured by the flow meter. A water treatment system characterized by having. In the water treatment system according to claim 6 ,
It is installed in the final settling basin or the outflow pipe from which the treated water flows out, and is equipped with an SS meter that measures the activated sludge concentration of the treated water.
When the activated sludge concentration of the treated water measured by the SS meter exceeds the preset activated sludge concentration upper limit value of the treated water, the flow rate adjusting valve opening control unit determines the treated water measured by the SS meter. A water treatment system characterized in that the opening degree of the flow rate adjusting valve is controlled by feedback control so that the activated sludge concentration of the above does not exceed the activated sludge concentration upper limit value of the treated water. In the water treatment system according to claim 6 ,
It is installed in the first connection pipe and includes an inflow water quality estimation unit that estimates the quality of the water to be treated flowing into the reaction vessel.
The water treatment control device is
The water quality estimation value of the water to be treated flowing into the reaction tank by the inflow water quality estimation unit, the activated sludge concentration measurement value measured by the MLSS meter, and the treatment to be treated flowing into the reaction tank measured by the flow meter. Equipped with a removal amount estimation unit that estimates the amount of organic matter removed by the reaction tank based on the flow rate of water.
The flow rate adjusting valve opening degree control unit removes organic substances by the reaction tank estimated by the flow rate upper limit value of the water to be treated or the removal amount estimation unit calculated by the flow rate upper limit value calculation unit. A water treatment system characterized in that the opening degree of the flow rate adjusting valve is controlled based on the amount. In the water treatment system according to claim 9 .
The removal amount estimation unit calculates the maximum flow rate of the water to be treated flowing into the reaction tank, which maximizes the amount of organic matter removed by the reaction tank.
The flow rate adjusting valve opening degree control unit compares the maximized flow rate calculated by the removal amount estimation unit with the flow rate upper limit value of the water to be treated flowing into the reaction tank calculated by the flow rate upper limit value calculation unit. A water treatment system characterized in that the opening degree of the flow rate adjusting valve is controlled by setting any one of the small values as the flow rate set value.

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