JPH04367795A - Operation supporting device of sewage treatment station - Google Patents

Abstract

PURPOSE:To make it possible to put sewage treatment into practice based on an optimal control program by enabling a control program best suited for the present status of a plant to be formulated, and also simulating the quality of treated water previously after the execution of a prepared returned sludge control program to enable a highly reliable control program to be developed. CONSTITUTION:A control program development part 24 changes the algorithm and control parameters of a water treatment control program to the best suited for a status quo, based on various types of process data and water quality analysis data obtained from a sewage treatment station. In addition, a water quality simulation part 26 simulates a water treatment control program incorporating changed control algorithm and control parameters. Further, a time-series data indication part 23 displays simulation results time-wise together with the mentioned process data based on the current water process program. A control program replacement execution part 25 replaces the water treatment control program with a changed program, if the display result is satisfactory.

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 that processes sewage using an activated sludge method.

0002

BACKGROUND OF THE INVENTION Conventionally, sewage treatment plants have treated sewage by biological wastewater treatment methods such as activated sludge methods.

[0003] In the control using the activated sludge method, the dissolved oxygen concentration (DO) in the aeration tank is controlled by the aeration air volume.
O control, MLSS control that controls the MLSS concentration in the aeration tank by returning or withdrawing sludge, etc. are applied singly or in combination.

[0004] This activated sludge method removes contaminated organic matter and suspended substances SS from the sewage by bringing activated sludge, which is a collection of various microorganisms mainly aerobic bacteria or facultative bacteria, into contact with sewage. Remove. Furthermore, since the activated sludge method utilizes the living activities of living organisms, 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 collection of microorganisms, changes in the water quality of the contact sewage also cause changes in the microbial ecosystem. Therefore, water treatment control using the activated sludge method must be a control method that can respond to changes in the microbial ecosystem.

[0006] On the other hand, the quality and quantity of sewage treated by a sewage treatment plant changes depending on the season, weather, and time, as well as changes in the urban structure of the inflow basin and changes in the standard of living.

[0007]

[Problems to be Solved by the Invention] However, with conventional water treatment equipment using the activated sludge method, after several years have passed since the installation of the equipment, the water quality and quantity of the inflowing sewage at the time of installation will change, as mentioned above, and the urban structure of the inflowing basin will change. Due to changes in the environment and standard of living, etc., the situation is significantly different from when it was first installed, and over many years of use, equipment deterioration occurs such as the aeration tank's diffuser becoming clogged and the oxygen supply capacity decreasing. Processing capacity has decreased, and the control algorithm originally installed cannot cope with the problem.

[0008] In order to solve these problems, the above-mentioned conventional apparatus deals with the problem only by changing the parameters without changing the control algorithm. However, changing parameters alone has limitations and becomes ineffective after several years have passed since the change. Moreover, the activated sludge method, which has a slow response, has the disadvantage that it takes a long time, ranging from several days to several months, to conduct its evaluation.

The present invention has been made in view of the above circumstances, and its purpose is to provide a sewage treatment plant operation support system that can change the control algorithm to suit the current situation and execute processing based on the optimal control program. Our goal is to provide the following.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention adapts the algorithm and control parameters of a water treatment control program to the current situation based on various process data and water quality analysis data from a sewage treatment plant. a simulation means for simulating a water treatment control program in which the control algorithm and control parameters have been changed; and a display means for displaying simulation results in chronological order together with the process data based on the current water treatment program; The apparatus includes program replacement means for replacing the water treatment control program with a modified one in response to an operator's instruction if the displayed simulation results are good.

[0011]

[Operation] When changing not only the control parameters of the program but also the control algorithm, the algorithm of the water treatment control program is based on the manual analysis data of inflow water quality by a water quality analyst etc. and the process data collected from the sewage treatment plant. and the control parameters are changed to suit the current situation. The changed control program is simulated to examine the validity of the changed control program. Simulation results are displayed in chronological order along with current process data. The operator determines from this display whether the changed program is good or not, and if it is good, replaces the control program with the changed one and stores it in the device.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

First, the configuration of the sewage treatment plant of this embodiment will be explained. As shown in the figure, an initial sedimentation tank 1, an aeration tank 2, and a final sedimentation tank 3 are arranged in series. The inlet pipe A of the initial settling tank 1 includes a flow meter 4 and a suspended matter concentration meter 5.
is installed, and the flow rate and suspended solids concentration of the treated water flowing into the initial settling tank 1 are measured.

[0014] The first settling tank 1 is provided with a pump 6 for drawing out the settled sludge from the bottom thereof, and the final settling tank 3
Pipe B connecting the bottom of the final settling tank 3 and the inflow side of the aeration tank 2 includes a return sludge pump 7 for returning part of the sludge settled at the bottom of the final settling tank 3 to the aeration tank 2, and a return sludge pump 7 for measuring the return flow rate. A return sludge flow meter 8 for measuring the return sludge concentration and a return sludge concentration meter 9 for measuring the concentration of the return sludge are provided. Furthermore, M of aeration tank 2
The LSS concentration is measured by the MLSS concentration meter 10.

The measurement signals (process data) of the flowmeter 4, suspended matter concentration meter 5, return sludge flowmeter 8, and return sludge concentration meter 9 are supplied to the operation support device 20 via the process data collection section 11. has been done.

The operation support device 20 includes a process data input unit 21 that receives process data from the process data collection unit 11, and a manual analysis data input unit 21 that receives process data input by a water quality analyst through an input/output processing unit 30. An input section 22, a time series data display section 23 that displays time series trend graphs such as those shown in FIGS. 2 and 4, a control program development section 24 that creates a return sludge control program suitable for the current situation, and A control program replacement execution unit 25 that replaces the sludge control program with a created new return sludge control program; a simulation unit 26 that performs simulation to determine the suitability of the created return sludge control program; The control program storage unit 27 includes a control program storage unit 27 for storing the control program, and a control program calculation value input unit 29 for inputting the control target value calculated by the control controller 40 and the intermediate results of the control calculation into the database 28.

The controller 40 performs control calculations on the returned sludge to obtain a target value for the amount of returned sludge, as will be described later, and outputs an operation command corresponding to the target value to the pump 7.

Next, the operation of this embodiment will be explained.

Sewage flowing into the sewage treatment plant first flows into the settling tank 1 through a pipe A in which a flow meter 4 and a suspended matter concentration meter 5 are installed. In the initial settling tank 1, suspended matter in the wastewater settles under its own weight, and is drawn out and removed by the pump 6. The sewage that has passed through the initial settling tank 1 flows into the aeration tank 2, where it is mixed with the thickened sludge returned from the final settling tank 3, and undergoes a biochemical reaction and a flocculation reaction.

The mixed liquid that has undergone the reaction in the aeration tank 2 flows into the final settling tank 3, where clear treated water and sludge are separated. The sludge in the final settling tank 3 is sent to the return sludge pump 7
is returned to the aeration tank 2 through pipe B.

The measurement signals of the flow meter 4, suspended matter concentration meter 5, return sludge flow meter 8, and return sludge concentration meter 9 are collected by the process data collection section 11, and are sent to the operation support via the process data input section 21. It is taken into the device 20. The captured process data is stored in the database 29.

On the other hand, the BOD in the treated water after passing through the final settling tank 3, which has been manually analyzed by a water quality analyst, is determined by the input/output processing section 3.
0 and is taken into the driving support device 20 via the manual analysis data input section 22. The captured manual analysis data is stored in the database 19. Further, in the control controller 40, a control target value is calculated, and the control target value and intermediate results of the control calculation are taken into the driving support device 20 via the control program calculation value input section 28. The captured control target values and intermediate results of control calculations are stored in the database 29.

In the controller 40, control calculations for the returned sludge are performed, for example, as follows.

En (t)=MLSSpv−MLSSsv
......(1) Q
R(t)=RR×Qat+K×En(t)
…………(2) However, MLSSpv: MLSS measured value MLSSsv: MLSS target value En (t): Deviation of MLSS measured value from MLSS target value (input deviation) QR (t): Returned sludge amount target value RR: Target return rate K: Constant Qat: Amount of water flowing into the aeration tank.

Return sludge control is executed by controlling the operation 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 section 23 to display the input data as a trend graph as shown in FIG. 2, and monitors changes in water quality and water quantity. Figure 2 shows the sewage treatment plant inflow flow rate, suspended solids concentration, MLSS concentration in aeration tank 2, return sludge flow rate, and return sludge concentration as process data, and the final settling tank outflow BO as manual analysis data.
D is displayed together with the MLSS concentration of the control target value.

[0027] After the operator compares the displayed trend graphs and understands the current state of the plant and the response of the control device thereto, the operator uses the control program development section 24 to create a return sludge control program that is suitable for the current situation. . A specific example is shown below.

En (t)=MLSSpv−MLSSsv
………(3) ΔQR
(t)=Kc×{Kp×(En (t-1)−En
(t)) +h×En
(t)/Ti }×Qat …………
(4) QR(t)=(QR(t-1)+ΔQR
(t)) …………(5) However, ΔQR: Returned sludge amount output deviation (output deviation) Kc:
Cascade gain Kp: Proportional gain h: Control period Ti: Integral time Qat: Aeration tank inflow water amount En (t-1): Previous value of input deviation QR (t-1): Previous value of return sludge amount target 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 determined by the control program, that is, the return sludge amount target value. The simulation process executed by the water quality simulation section 26 is shown in the flowchart of FIG.

In FIG. 3, when the operator specifies a control program to be considered, first, process data such as the current aeration tank inflow flow rate, aeration tank MLSS concentration, and return sludge amount are read from the database 29 (step ST1);
Next, the control program created by the control process development section 24 is executed (step ST2), and the obtained control target value (return sludge amount target value) is output (step ST3).
). The above simulation process is repeated until an end command is received from the operator (step ST4).

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

In FIG. 4, when the control target value, that is, the target value of the amount of returned sludge is changed to the value determined by the control program, the simulated value of the amount of returned sludge changes as shown by the broken line. The operator examines the validity of the control program by looking at this trend graph.

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

As described above, according to this embodiment, it is possible to create a return sludge control program suitable for the current properties and conditions of sludge. It is also possible to simulate in advance the quality of treated water after executing the created return sludge control program.
It becomes possible to develop more reliable control programs.

[0035] In this embodiment, control of the amount of returned sludge has been explained as an example, but the present invention is not limited to this, and can be applied to various other methods such as control of extracting excess sludge, control of aeration air volume, control of water treatment plant chemical injection, etc. It can also be adapted to devices that support the operation of sewage treatment plants.

[0036]

As explained above, according to the present invention, it is possible to create a control program that is compatible with the current state of the plant. Furthermore, the quality of treated water after executing the created return sludge control program can be simulated in advance, making it possible to develop a more reliable control program and executing treatment based on this optimal control program.

[Brief explanation of the drawing]

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

FIG. 2 is an explanatory diagram showing plant information in chronological order.

FIG. 3 is a flowchart showing a simulation process executed by a simulation section.

FIG. 4 is an explanatory diagram showing simulation results and plant information in chronological order.

[Explanation of symbols]

1 Initial settling tank 2 Aeration tank 3 Final settling tank 20 Operation support device 21 Process data input section 22 Manual analysis data input section 23 Time series data display section 24 Control program development section 25 Control program replacement execution section 26 Simulation section 27 Return sludge control Program storage section 28 Control program calculation value input section 29 Database 40 Control controller

Claims (1)

[Claims] [Claim 1] A means for changing an algorithm and control parameters of a water treatment control program to ones that suit the current situation based on various process data and water quality analysis data from a sewage treatment plant, and a means for changing the control algorithm and control parameters. a simulation means for simulating a water treatment control program based on the current water treatment program; a display means for displaying the simulation results in chronological order together with the process data based on the current water treatment program; A sewage treatment plant operation support device comprising: program replacement means for replacing a treatment control program with a changed one;