JPH07259745A - Refluent water control method for rainwater stagnating pond - Google Patents

Abstract

PURPOSE:To perform macro-optimization of control of refluent water by operating and stopping a refluent water pump based on a refluent timing signal determined through fuzzy inference and a refluent time signal and based on a deviation between a return flow rate signal and an actual refluent flow rate, and controlling a speed to control a flow rate of refluent water. CONSTITUTION:A storage amount signal LA, a pumping-up amount signal FA being an output from a flow meter 10, and a refluent emergency degree signal EA produce an input variable, and inference of a refluent time signal TA indicating an operation time of a refluenting water pump and a refluent flow amount signal HF being a target is effected through fuzzy inference. Based on a water level signal LB, a pumping up amount signal FB, a storage time signal TB for rainwater storing in each sedimentation pond, and a time signal TS indicating a time zone executing a return flow, being an input variable, a return flow timing signal CL for the starting of a refluent water pump 6 is outputted through fuzzy inference. A refluent flow amount signal HF and an actual return flow rate signal GF, being an output from a flow meter 7, are inputted and an output generated through proportional integration of a deviation therebetween is fed to a refluent water pump 6 to control a speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a return water control method for returning a rainwater retention tank in a sewage process to a treatment plant water treatment facility (first settling tank).

[0002]

2. Description of the Related Art Rainwater removal is to efficiently collect rainwater in urban areas due to rainfall or the like and discharge it to a river or the like.
Inundation damage tends to increase due to the increase of rainwater runoff and shortening of runoff time due to the reduction of infiltration area due to the rapid urbanization in recent years, frequent local heavy rainfall, acceleration of ground subsidence, etc. Measures are required as a major urban disaster.

As measures against this, in addition to rainwater drainage facilities, rainwater outflow control measures for improving water retention and water retention functions are being promoted, and the aim is to reduce water damage and improve water quality of rainwater discharge.

A rainwater retention pond is provided as a typical facility for controlling the outflow of rainwater, and is provided for the purpose of temporarily storing high turbidity rainwater at the time of initial rainfall or unbreakable rainwater that cannot be covered by pumping equipment in the combined sewer system. .

The rainwater retention basin has a structure in which rainwater is stored in a plurality of settling basins, and inorganic substances and the like in the stored rainwater are removed by gravity settling, and fluctuations in the amount of treated water in the next stage water treatment facility. That is, in response to fluctuations in the amount of pumped water from the pumping equipment, it is pumped as return water to the first settling tank of the water treatment equipment by the return water pump.

[0006]

At this time, it is necessary to control the return water for optimal return flow, but the present technology has the following problems.

(1) Return water control is not performed in consideration of the storage amount and pumping amount of a rainwater resistant pond composed of a plurality of settling basins.

(2) The determination of the return timing depends on the operator and is a burden on the operator.

(3) Since the return flow time is fixed and the return flow rate is constant, there is basically no flexible system capable of coping with changes in the pumping condition from the pumping equipment at the treatment plant. For this reason, there is a possibility that it may adversely affect the treatment process in the latter stage, and the optimum return water control is not performed.

(4) From the above, there is a possibility that the operating time of the return water pump will be long and the electric energy will be wasted.

The present invention has been conceived in view of the above problems, and provides a macroscopically optimum return water control method by considering the storage amount of a rainwater retaining tank (sedimentation tank) and the pumping amount from a pumping facility. The purpose is to do.

[0012]

[Means and Actions for Solving Problems] Rainwater in the sewer process is temporarily stored in a holding tank (sedimentation tank), subjected to sedimentation treatment, and the treated rainwater is returned to the water treatment facility (first sedimentation tank) at the treatment plant. In the return water control that pumps the return water by the flow water pump, the target return flow rate signal and the return flow signal based on the storage signal of the rainwater retention reservoir, the pumping amount signal pumped from the pumping equipment to the water treatment equipment, and the return emergency signal. Fuzzy inference is performed on the return time signal indicating the flow period, and on the basis of the water level signal of the reservoir, the rainwater retention time signal, the pumping signal, and the return timing signal related to the pump start based on the time signal indicating the return time zone. Based on the deviation between the return flow rate signal and the actual return flow rate signal, speed control is performed based on the deviation between the return flow rate signal and the actual return flow rate signal. Control.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention is shown in FIG.
The membership function of FIG. 2 and the rule matrix of Tables 1 and 2 will be described.

1 is a confluent rainwater inflow pit, 2 is a settling basin which serves as a rainwater retention basin for storing rainwater flowing in from the inflow pit 1 and removing inorganic substances and the like by gravity settling action, and 3 This is a water level gauge installed in the sedimentation basin. A washing water tank 4 stores water for washing the sediment in the settling tank 2, and a pump 5 for pumping the washing water to the settling tank 2.

Reference numeral 6 is a return pump for pumping rainwater treated in the settling tank 2 to the treatment plant water treatment facility (first settling place) 8, and 7 is a flow meter for measuring the flow rate of the return water. A flow meter 10 measures the amount of rainwater or sewage pumped from the treatment plant pumping equipment (rainwater pump or sewage pump) 9 to the treatment plant water treatment equipment 8.

A storage amount calculation means 11 calculates the storage amount from the water level signal LB, which is the output of the water level gauge 3 of the settling basin 2, and the settling basin area, and outputs the stored amount signal LA.

Reference numeral 12 is a first fuzzy inference means, which uses the stored amount signal LA, the pumped water amount signal FA which is the output of the flowmeter 10 and the return emergency signal EA as input variables to perform the fuzzy inference of the return water pump. A return time signal TA indicating the operating time and a target return flow rate signal HF are inferred.

Reference numeral 13 is a second fuzzy inference means,
Returned by fuzzy inference using the water level signal LB, the pumped water amount signal FB (= FA), the rainwater retention time signal TB stored in each sedimentation tank and the time signal TS indicating the time period for performing the return flow as input variables. A return timing signal CL for starting the running water pump is output.

Reference numeral 14 is an adjusting means, which inputs the return flow rate signal HF and the actual return flow rate signal GF which is the output of the flow meter 7, and feeds the output obtained by proportionally and integrating the deviation thereof to the return water pump 6. To do.

Reference numeral 15 is a control means, which receives the return time signal TA and the return timing signal CL and receives the return water pump 6
Control the operation / stop of the.

Next, the operation will be described.

Rainwater passes through the inflow pit 1 and flows into and is stored in the settling basin 2 which functions as a rainwater retaining basin. The water level signal LB detected by the water level gauge 3 provided in the settling basin 2 is input to the storage amount calculation means 11, the storage flow rate is calculated by calculation with the area of the settling basin 2, and the storage amount signal LA is the first. It is input to the fuzzy inference means 12. Further, the flowmeter 10 detects the amount of pumped water pumped from the treatment plant pumping equipment 9 to the treatment plant water treatment equipment 8, and inputs it to the first fuzzy inference means 12 as a pumping amount signal FA. Further, the operator sets the return flow emergency signal EA indicating the urgency of the return flow and inputs it to the first fuzzy inference means 12.

In the first fuzzy inference means 12, the storage variable signal LA, the pumped-up signal FA, the return emergency signal EA and the output variable (cause item) which are the input variables (phenomenon items).
The return time signal TA and the return flow rate signal HF are defined as a three-stage membership function of L, M, and S as shown in FIG. 2, and a rule matrix for inference is defined as shown in Table 1. . I according to this rule matrix
The return time signal TA and the return flow rate signal HF are inferred based on the F-THEN rule, and the former is sent to the control means 15 and the latter is sent to the return flow control means 14.

[0024]

[Table 1]

On the other hand, in the second fuzzy inference means 13,
The water level signal LB, the pumped water amount signal FB (= FA), the storage time signal TB, and the time signal TS are input. In the second fuzzy inference means 13, the water level signal LB, the pumping amount signal FB, the storage time signal TB, the time signal TS, which are the input variables (phenomenon items), and the return timing signal CL, which is the output variable (cause item). As shown in FIG.
It is defined as a three-stage membership function of M and S, and a rule matrix for inference is defined as shown in Table 2. IF ~ THEN depending on this rule matrix
The return timing signal CL is inferred based on the rule and sent to the control means 14.

[0026]

[Table 2]

The return water pump 6 is activated by receiving an operation command based on the return timing signal CL from the control means 15, and the return flow rate signal HF from the adjusting means 14 and the actual return flow which is the output of the flow meter 7. A variable speed operation is performed by a drive command (speed command) based on a deviation from the signal GF, and a stop command is received from the control means 15 based on the return time signal TA to perform an operation of stopping and adjust the flow rate of the return water.

[0028]

INDUSTRIAL APPLICABILITY The present invention, in the return water control of a rainwater retention pond, a return flow rate signal and a rainwater retention time signal based on the retention volume signal of the retention pond, the pumping quantity signal from the pumping equipment, and the return emergency signal. In addition to fuzzy inference, the return timing signal is inferred based on the water level signal of the holding pond, the pumping volume signal, the rainwater retention time signal, and the time signal indicating the time zone for returning water to operate the return water pump. Since the return water is diverted by stopping and controlling the speed, the optimum return water control can be performed macroscopically. Since the return time and return time are variable and can respond to changes in the pumping situation, it is possible to reduce load fluctuations in the subsequent treatment process and contribute to improvement in water quality. In addition, since the return timing is automatically determined, the burden on the operator is reduced.

The operation time of the return water pump is reduced, and energy saving of electric power is expected. At the same time, it is possible to save electric energy of the cleaning estimation and the electric power of the cleaning pump. Furthermore, since the fuzzy inference is used, it has a flexible analogic structure, and it is easy to change or modify the rules.

[Brief description of drawings]

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

FIG. 2 is a membership function of input / output variables.

[Explanation of symbols]

 2: Sedimentation basin (1 to n) 3: Water level meter 6: Return water pump 7, 10: Flow meter 8: Treatment plant water treatment equipment 9: Treatment plant pumping equipment 11: Storage amount calculation means 12: First fuzzy Inference means 13: Second fuzzy inference means 14: Adjusting means 15: Control means

Claims (1)

[Claims] 1. A return water control system for temporarily storing rainwater in a rainwater retention tank (sedimentation tank), performing sedimentation treatment, and pumping the treated rainwater to a water treatment facility (first sedimentation tank) at the treatment plant, in a rainwater retention water reservoir. The storage amount signal, the pumping amount signal for pumping from the pumping facility to the water treatment facility (first settling basin), the return urgency signal as input variables, and the target return flow rate signal and return time signal indicating the return period. The first fuzzy inference means for performing fuzzy inference as an output variable, and the pump start-up using the water level signal of the rainwater retention reservoir, the rainwater retention time signal, the pumping amount signal and the return time signal indicating the return time zone as input variables Second fuzzy inference means for fuzzy inference using a return timing signal as an output variable, control means for instructing operation / stop of a return water pump based on the return timing signal and return time signal, and the return flow rate signal And a return means for controlling the flow rate of the return water pump based on the deviation between the return flow rate signal and the actual return flow rate signal.