JP3181315B2 - Sewage treatment plant operation support equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supporting the operation of a sewage treatment plant for treating sewage by the activated sludge method.

[0002]

2. Description of the Related Art Conventionally, in a sewage treatment plant, sewage is treated by a biological wastewater treatment method such as an activated sludge method.

In the control by the activated sludge method, a dissolved oxygen concentration (DO) in an aeration tank is controlled by an aeration air flow.
O control, MLSS control for controlling the MLSS concentration in the aeration tank by returning or extracting sludge, or the like is applied alone or in combination.

In this activated sludge method, activated sludge, which is an aggregate of various microorganisms mainly composed of aerobic bacteria or facultative bacteria, is brought into contact with sewage to remove contaminated organic substances and suspended solids SS in the sewage. Remove. In addition, the activated sludge method utilizes the living activities of living organisms, and its treatment efficiency is high and stable only when the activated sludge is maintained in a healthy state.

[0005] Since this activated sludge is a complex aggregate of microorganisms, a change in the quality of the contact sewage causes a change in the ecosystem of the microorganisms. Therefore, water treatment control by the activated sludge method must be a control method that can respond to changes in the ecosystem of microorganisms.

On the other hand, the quality and quantity of sewage to be treated by a sewage treatment plant change according to the season, weather, time, and also due to changes in the urban structure of the inflow basin, changes in living standards, and the like.

[0007]

However, in a conventional water treatment apparatus using the activated sludge method, after several years have passed since the installation of the apparatus, the water quality and quantity of the inflow sewage at the beginning of the installation are reduced as described above. Is significantly different from that at the beginning of installation due to changes in water quality and living standards, and due to long-term use, equipment deterioration such as a decrease in oxygen supply capacity due to clogging of the air diffuser in the aeration tank. The processing capacity is reduced, and the control algorithm at the beginning of installation cannot cope with it.

Therefore, in order to solve such a problem, the above-described conventional apparatus deals only with changing parameters without changing the control algorithm. However, changing the parameters alone has limitations and becomes ineffective after several years from the change. Moreover, the activated sludge method having a slow response has a problem that it takes a long time of several days to several months to evaluate the activated sludge method.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sewage treatment plant operation support device capable of changing a control algorithm to one adapted to the present situation and executing a process based on an optimal control program. Is to provide.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a water supply system for executing feedback control for bringing a measured value closer to a target value based on various process data and water quality analysis data from a sewage treatment plant. Means for changing the algorithm and control parameters of the treatment control program to those suitable for the current situation; simulation means including a water quality simulation unit for simulating a water treatment control program in which the control algorithm and control parameters have been changed; and Display means for displaying the process data based on the water treatment program in chronological order together with the process data, and program replacement means for replacing the water treatment control program with the changed one according to the instruction of the operator when the displayed simulation result is good. thing It is an feature.

[0011]

When changing not only the control parameters of the program but also the control algorithm, the measured value is set to the target value based on the manual analysis data of the inflow water quality by the water quality analysts and the process data collected from the sewage treatment plant. The algorithm and control parameters of the water treatment control program for executing the feedback control approaching the above are changed to those suitable for the current situation. The changed control program is simulated by the simulation means including the water quality simulation unit in order to examine the validity of the changed control program. Simulation results are displayed in chronological order along with the current process data. From this display, the operator determines whether or not the change program is good. If the change program is good, the operator replaces the control program with the changed program and stores it in the apparatus.

[0012]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

First, the configuration of the sewage treatment plant according to the present embodiment will be described. As shown in the figure, a first settling tank 1, an aeration tank 2, and a last settling tank 3 are arranged in series. A flow meter 4 and a suspended solids concentration meter 5 are provided in the inflow line A of the first settling tank 1.
The flow rate of the treated water flowing into the sedimentation basin 1 and the concentration of the suspended solids are measured.

The first settling basin 1 is provided with a pump 6 for pulling out sludge settled at the bottom thereof.
A return sludge pump 7 for returning a part of the sludge settled at the bottom of the final sedimentation basin 3 to the aeration tank 2 is provided in a pipeline B connecting the bottom of the sludge and the inflow side of the aeration tank 2, and measures the return flow rate thereof. A return sludge flow meter 8 and a return sludge concentration meter 9 for measuring the return sludge concentration are provided. Further, M of the aeration tank 2
The LSS concentration is measured by the MLSS densitometer 10.

Each measurement signal (process data) of the flow meter 4, the suspended matter concentration meter 5, the returned sludge flow meter 8, and the returned sludge concentration meter 9 is supplied to the operation support device 20 via the process data collection unit 11. Have been.

The driving support device 20 includes a process data input unit 21 for taking in process data from the process data collection unit 11 and a hand analysis data for taking in hand analysis data input by the water quality analyst via the input / output processing unit 30. An input unit 22, a time-series data display unit 23 for displaying a time-series trend graph as shown in FIGS. 2 and 4, a control program development unit 24 for creating a return sludge control program suitable for the current situation, and a previous return A control program replacement execution unit 25 that replaces the sludge control program with the newly created return sludge control program; a water quality simulation unit 26 that simulates to determine the suitability of the created return sludge control program; And a control program storage unit 27 for storing A control program operation value input unit 29 for inputting an intermediate result of the control target value and the control calculations in the database 28 that is provided with a.

The control controller 40 performs a return sludge control operation as described later to obtain a target value of the return sludge amount, and outputs an operation command corresponding to the target value to the pump 7.

Next, the operation of this embodiment will be described.

The sewage flowing into the sewage treatment plant first flows into the sedimentation basin 1 through a pipe A in which a flow meter 4 and a suspended matter concentration meter 5 are provided. In the first sedimentation basin 1, suspended matter in the sewage sediments under its own weight, and is drawn out and removed by the pump 6. The sewage that first passed through the sedimentation basin 1 flows into the aeration tank 2, is mixed with the concentrated sludge returned from the final sedimentation basin 3, and undergoes a biochemical reaction and a coagulation reaction.

The mixed solution that has undergone the reaction in the aeration tank 2 flows into the final sedimentation basin 3, where clear treated water and sludge are separated. Sludge from the final settling basin 3 is returned to the sludge pump 7
Is returned to the aeration tank 2 through the pipe B.

The measurement signals of the flow meter 4, the suspended matter concentration meter 5, the returned sludge flow meter 8 and the returned sludge concentration meter 9 are collected by the process data collection unit 11 and are supported through the process data input unit 21. It is taken into the device 20.
The fetched process data is stored in the database 29.

On the other hand, the BOD in the treated water after passing through the final sedimentation basin 3 that has been manually analyzed by the water
0 and is taken into the driving support device 20 via the hand analysis data input unit 22. The acquired hand analysis data is accumulated in the database 19. Further, the control controller 40 calculates a control target value, and the control target value and an intermediate result of the control calculation are taken into the driving support device 20 via the control program calculation value input unit 28. The acquired control target values and intermediate results of the control calculations are accumulated in the database 29.

In the control controller 40, the control calculation of the returned sludge is performed, for example, as follows.

[0024] _{E n (t) = MLSS pv} -MLSS sv ............ (1) QR (t) = R R × Q at + K × E n (t) ............ (2) However, MLSS _pv: MLSS measurements MLSS _sv: MLSS target value E _n (t): deviation (input deviation) from MLSS target value of MLSS measurements QR (t): return sludge amount target value R _R: target return rate K: constant Q _at : The amount of water flowing into the aeration tank.

The return sludge control is executed by the operation control of the pump 7 based on the return sludge target value QR (t) created in this way.

The operator uses the time-series data display unit 23 to display the input data in a trend graph as shown in FIG. 2 and monitors changes in water quality and quantity. FIG. 2 shows the sewage treatment plant inflow flow rate, suspended solids concentration, MLSS concentration in the aeration tank 2, return sludge flow rate and return sludge concentration as process data, and final sedimentation tank discharge B as hand analysis data.
The OD is displayed together with the MLSS concentration of the control target value.

The operator compares the displayed trend graph to grasp the current state of the plant and the response of the control device to the current state, and then creates a return sludge control program suitable for the present situation using the control program development unit 24. .
Specific examples are shown below.

[0028] _{E n (t) = MLSS pv} -MLSS sv ............ (3) ΔQR (t) = K c × {K p × (E n (t-1) -E n (t)) + h × _{E n (t) / T i} } × Q at ............ (4) QR (t) = (QR (t-1) + ΔQR (t)) ............ (5) However, AQr: return sludge quantity output deviation (output deviation) K _c: cascade gain K _p: proportional gain h: control period T _i: integral time Q _at: aeration tank inflow water amount E _n (t-1): input deviation previous value QR (t-1) : Return sludge amount target value Previous value.

Next, in order to examine the validity of the created control program, the water quality simulation section 26 executes a simulation based on the control target value obtained by the control program, that is, the return sludge amount target value. The simulation process executed by the water quality simulation unit 26 is shown in the flowchart of FIG.

In FIG. 3, when a control program to be examined by the operator is designated, first, process data such as the current inflow rate of the aeration tank, MLSS concentration of the aeration tank, and amount of returned sludge are read from the database 29 (step ST).
1) Then, the control program created by the control process development unit 24 is executed (step ST2), and the obtained control target value (return sludge amount target value) is output (step ST3). The above simulation processing is repeated until there is an end command from the operator (step ST4).

The result of the simulation is as follows.
As shown in FIG. 4, the time-series data display unit 23 displays the data together with the process data. The inflow flow rate, the inflow concentration, the return sludge flow rate, the return sludge concentration, the MLSS concentration in the aeration tank 2 used in the simulation, and the final sedimentation tank outflow BOD, which is manual analysis data, are displayed as solid lines.

In FIG. 4, the simulation value of the return sludge amount when the control target value, that is, the return sludge amount target value is changed to a value obtained by the control program, changes as shown by the broken line. The operator examines the trend graph to determine the validity of the control program.

If the result is good, the operator replaces the control program in the control controller 40 with the changed control program. The returned sludge amount is controlled by the replaced new control program.

As described above, according to this embodiment, it is possible to create a return sludge control program suitable for the current sludge properties and conditions. In addition, it is possible to simulate in advance the quality of treated water after executing the created return sludge control program,
A more reliable control program can be developed.

In this embodiment, the control of the amount of returned sludge has been described as an example. However, the present invention is not limited to this, and various controls such as control of pulling out excess sludge, control of aeration air volume, control of chemical injection in a water purification plant, etc. It can also be applied to devices that support the operation of sewage treatment plants.

[0036]

As described above, according to the present invention, a control program suitable for the current state of the plant can be created.
Moreover, the quality of the treated water after the execution of the created return sludge control program can be simulated in advance, and a more reliable control program can be developed, and processing based on this optimal control program can be executed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing plant information in time series.

FIG. 3 is a flowchart illustrating a simulation process executed by a simulation unit.

FIG. 4 is an explanatory diagram showing a simulation result and plant information in time series.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 First sedimentation tank 2 Aeration tank 3 Final sedimentation tank 20 Operation support device 21 Process data input part 22 Hand analysis data input part 23 Time series data display part 24 Control program development part 25 Control program replacement execution part 26 Simulation part 27 Return sludge control Program storage unit 28 Control program operation value input unit 29 Database 40 Control controller

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-82896 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C02F 3/12

Claims (1)

(57) [Claims] 1. An algorithm and a control parameter of a water treatment control program for executing a feedback control for bringing a measured value close to a target value based on various process data and water quality analysis data from a sewage treatment plant are changed to those adapted to the present condition. Means for performing, a simulation means including a water quality simulation unit for simulating a water treatment control program in which a control algorithm and a control parameter are changed, and display means for displaying a simulation result in a time series with the process data based on a current water treatment program. A sewage treatment plant operation support device, comprising: a program replacement unit that replaces a water treatment control program with a changed one according to an instruction of an operator when a displayed simulation result is good.