JPH02293090A - Device for detecting overinjection of liquid disinfectant in sewage treatment - Google Patents

Abstract

PURPOSE:To surely detect overinjection of a liq. disinfectant by calculating the estimated value for the residual disinfectant based on the disinfectant conc., detecting the value for the flow rate of treated sewage and detection value for the disinfectant supply, detecting the disinfectant remaining in the treated sewage at the outlet, comparing both values and issuing an alarm when the latter is excessive. CONSTITUTION:The concn. of chlorine remaining in treated water is estimated by the residual chlorine value arithmetic unit 15 base on the detection value for chlorine injection, detection value for the treated water flow rate and liq. chemical concn. The residual chlorine concn-estimated value is delayed by a delay unit 16 corresponding to the reaction time in a chlorine-contact water passage 1. The estimated value for the delayed residual chlorine concn. and the detection value for the residual chlorine concn. in the treated water at the outlet are compared by a comparator unit 17. When the deviation of the detection value from the estimated value exceeds a threshold value, an overinjection alarm is issued. Accordingly, even when the chemical is overinjected due to the error or trouble of the chemical injection control system, the overinjection can be rapidly detected, and the reliability on the chemical injection system is advantageously improved.

Description

[Detailed Description of the Invention] A. INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a device for detecting over-injection of a disinfectant solution in a system for injecting a disinfectant solution into treated sewage water.

B. Summary of the Invention The present invention calculates an estimated value of chemical component residual ik1 degree based on the drug r(1:I8U, the detected sewage water flow rate, and the detected value of the chemical supply amount), and calculates the estimated value of the residual concentration of the chemical component over the required time. By delaying and comparing the detected value of the residual concentration of chemical components in the sewage treatment water at the outlet side of the chemical injection channel, and notifying an alarm when the detected value of the residual concentration of chemical components is excessive, it is possible to ensure over-injection of chemical solutions. It is something to detect.

C. BACKGROUND OF THE INVENTION Generally, in sewage treatment plants, water discharged into rivers is treated with chemicals such as chlorine and sodium hypochlorite in order to sterilize bacteria such as large intestine bacteria.

Water quality standards for water discharged into rivers set an upper limit for residual chlorine concentration. In sewage treatment, the injection ratio of chemicals to the amount of effluent water is set so as not to exceed this upper limit, and chemicals are injected proportionally to the amount of effluent water.

FIG. 2 shows a conventional chlorine injection process/stem.

The treated water is made to flow through the chlorine contact waterway 1, and in the chlorine contact waterway 1, chlorine water supplied from the chlorine injection machine 2 is injected into the treated water and then discharged.

The flow rate of treated water to the chlorine contact waterway 1 is detected by a flowmeter 3. The ratio setter 4 calculates a target value for the amount of medicine to be injected from the set injection ratio and the detected value of the flow meter 2. This injection amount target value and the injection amount detected value from the injection amount detector 5 of the chlorine injection machine 2 are compared in a matching circuit 6, the deviation between the two is taken, and based on this deviation, the controller 7 The control valve 8 was to be controlled.

D. Problems to be Solved by the Invention However, with the above-described conventional processing/system, there is a problem in that it is difficult to detect excessive amounts of drugs.

In other words, it is possible to monitor whether or not the amount of chemical injection is excessive based on the injection amount detection value fed back from the injection amount detector 5 of the chlorine injection machine 2; If over-injection occurs due to errors such as 1 {*, etc., the over-injection could not be prevented, and there was a risk that the residual concentration of chemicals in the effluent would exceed the specified value.

In order to prevent such over-injection of chemicals, the operation of the chlorine injection system has become a task that requires extreme caution.

In view of these circumstances, an object of the present invention is to provide a device that reliably detects over-injection of a disinfectant in a device that injects a disinfectant into treated sewage water.

E. Means for Solving the Problems In order to achieve the above object, the present invention provides a chemical solution supply section that supplies a disinfecting chemical solution, detects the supply amount of this chemical solution,
A chemical liquid supply main detection unit that outputs a chemical liquid detection value, a chemical liquid injection waterway that injects the supplied chemical liquid into the sewage treatment water, and a flow rate of the sewage treatment water on the inlet side of this chemical liquid injection waterway are detected, and the sewage treatment is performed. A sewage treatment water flow rate detection unit that outputs a detected water flow rate, and a chemical supply that calculates a chemical supply amount from the detected flow rate value of the sewage treatment water, the chemical solution injection ratio, and the chemical solution supply amount detection value, and outputs a chemical solution supply amount instruction value. The present invention provides a disinfectant overfill detection device comprising the following means and used for controlling the chemical solution supply section based on the chemical solution supply amount instruction value.

■ A residual concentration estimator that calculates the residual concentration of the chemical component based on the chemical concentration, the detected sewage water flow rate, and the detected value of the chemical supply amount, and outputs the estimated residual concentration of the chemical component.

■ An estimated value delay section that delays the estimated residual concentration of drug components in response to the time required for drug reaction.

■ A residual concentration detection unit that detects the chemical components remaining in the treated sewage water on the outlet side of the chemical injection channel and outputs the detected value of the residual concentration of the chemical components.

■ A residual concentration monitoring unit that compares the estimated value of the residual TA level of the chemical liquid component delayed by the estimated value delay unit with the detected value of the residual 72° of the chemical liquid component, and notifies an alarm when the latter value is excessive.

F. In the present invention, the residual concentration detection unit detects the chemical components remaining in the treated sewage water at the outlet of the chemical injection channel, and the detected value of the residual concentration of the chemical components is fed back to detect over-injection of the chemical solution. .

In other words, based on the detected sewage water flow rate that indicates the flow rate of sewage treated water at the inlet side of the chemical injection channel, the detected chemical solution supply amount that indicates the amount of chemical solution supplied, and the chemical concentration input from the outside, the chemical composition is determined. The residual concentration estimator calculates an estimated residual concentration value of the chemical component indicating the residual concentration of the residual concentration. Then, after delaying this estimated value of the residual concentration of the chemical liquid component by a time corresponding to the reaction of the chemical liquid, it is compared with the detected value of the residual concentration of the chemical liquid component described above, and if the detected value of the residual concentration of the chemical liquid component is excessive, It determines that overfilling has occurred and issues an alarm.

G. Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a chlorine injection treatment system according to an embodiment of the present invention.

The chlorine contact waterway 1 is a waterway for injecting chlorine into the treated water. A flow meter 3 is installed on the inlet side of the chlorine contact waterway 1 to detect the flow rate of treated water. Further, a residual salt meter 9 is installed on the outlet side of the chlorine contact waterway 1 to detect the concentration of residual chlorine in the treated water.

The chlorine injection machine 2 is for injecting chlorine water into the chlorine contact waterway 1. The control valve 8 is a valve that controls the amount of chlorine injected. The injection amount detector 5 detects the injection amount of chlorine.

The arithmetic control unit 10 controls the chlorine injection process, and in this embodiment is configured using a CPU.

The ratio setting unit 1l holds an injection ratio set from the outside, and calculates the first chlorine injection (vote value) based on this injection ratio and the detected value of the treated water flow rate from the flow meter 3.The matching unit 12 compares the target value of chlorine injection amount from the ratio setting section 11 with the detected value of injection amount from the injection 1 detector 5, and calculates the deviation between the two. Based on the deviation, a chlorine injection amount instruction is obtained.The control valve 8 is operated according to this chlorine injection amount instruction.

A target value for chlorine injection into the chlorine contact waterway 1 is determined from the flow rate of treated water into the chlorine contact waterway 1 and the chlorine injection ratio. Based on this target value of chlorine injection amount, feed control is performed on the chlorine injection machine 2 to perform chlorine injection processing with appropriate IR.

The control deviation detection unit 14 calculates the deviation between the chlorine injection amount target value and the chlorine injection instruction, compares the deviation with a threshold value, and determines whether the deviation is excessive. It sometimes outputs an excessive control deviation alarm.

If an abnormality occurs in the control system of the control valve 8 and the deviation between the chlorine injection tank target value and the chlorine injection amount instruction becomes excessive, appropriate chlorine injection processing becomes difficult. The control deviation detection unit l4 monitors this deviation, determines that an abnormality has occurred when the deviation becomes excessive, and outputs an excessive control deviation alarm to an output device (not shown) such as an alarm device. .

The residual chlorine estimated value calculation unit 15 estimates the concentration of chlorine remaining in the treated water based on the detected value of the chlorine injection amount, the detected value of the treated water flow rate, and the 1 degree of chemical solution.

This calculation formula is shown below.

a・ρ/(a+b)=x (1) where a is the amount of chlorine injection, ρ is the chlorine concentration, b is the flow rate of treated water,
X is the estimated chlorine concentration (mg/+2).

The delay unit 16 delays the estimated residual chlorine concentration in accordance with the reaction time in the chlorine contact waterway 1 . Comparison unit 17 compares the delayed estimated residual chlorine concentration with the detected residual chlorine concentration, and when the deviation of the detected value from the estimated value exceeds a threshold (for example, if the threshold is O, the detected (when the value exceeds the estimated value), an overfill alarm is output.

When over-injection of chlorine occurs, the residual chlorine estimated value calculated from the flow meter 3 and the output of the injection lit alarm 5, etc.
The residual chlorine detection value that is actually detected will be a larger value. By delaying the estimated residual chlorine value in consideration of the chlorine reaction delay time, the estimated residual chlorine value and the detected residual chlorine value can be compared. The comparator 17 compares the two, and if, for example, the exhalation value exceeds the estimated value, it is determined that an abnormality has occurred and an over-injection alarm is output to the output device 7.

The residual chlorine high detection unit 18 outputs a residual chlorine high alarm when the detected residual chlorine concentration exceeds a threshold value.

As mentioned above, there is an upper limit for the residual chlorine concentration in treated sewage water that is discharged into rivers. When the residual chlorine concentration of the treated water from the chlorine contact waterway 1 exceeds a threshold value, the residual chlorine high detection section detects this and outputs a residual chlorine high alarm to the output device.

As explained above, according to this embodiment, excessive control deviation, excessive injection, and high residual chlorine are monitored, and an alarm is output if there is an abnormality, so the reliability of the chlorine injection treatment system is improved. There is.

1-1. Effects of the Invention As explained above, in the present invention, the residual 'tR degree detection section detects the chemical components remaining in the treated sewage water on the outlet side of the chemical injection channel, and feeds the detected value of the residual concentration of the chemical components. detects overfilling of chemical solution and issues an alarm.

Therefore, when over-injection of a chemical solution occurs due to an error or failure in the chemical solution injection control system, this can be detected accurately and quickly, which has the advantage of improving the reliability of the chemical solution injection processing system.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a chlorine injection treatment/stem according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional chlorine injection treatment system. l...Chlorine contact waterway, 2...Chlorine injection machine, 3...
Flow meter, 5...Injection amount detector, 8...Control valve, 1l...
...Ratio setting section, 12... Matching section, 5... Residual chlorine concentration estimated value calculation section, l7... Comparison section. Two-person outside adjustment department, ...delay department,

Claims (1)

[Claims] (1) A chemical supply unit that supplies a disinfecting chemical, a chemical supply amount detection unit that detects the supplied amount of this chemical and outputs a detected value of the chemical, and a unit that injects the supplied chemical into the treated sewage water. A sewage treatment water flow rate detection unit that detects the flow rate of sewage treatment water on the inlet side of this chemical injection canal and outputs a detected sewage treatment water flow rate value, and a sewage treatment water flow rate detection unit that detects the sewage treatment water flow rate detection value and chemical injection. A chemical solution supply control section that calculates a chemical solution supply amount from the ratio and a chemical solution supply amount detection value and outputs a chemical solution supply amount instruction value, and controls the chemical solution supply section based on the chemical solution supply amount instruction value, wherein: and a residual concentration estimator that calculates the residual concentration of the chemical component based on the detected value of the sewage treatment water flow rate and the detected value of the chemical supply amount, and outputs the estimated value of the residual concentration of the chemical component; an estimated value delay unit that delays the estimated value of the residual concentration of the chemical liquid component; a residual concentration detection unit that detects the chemical liquid component remaining in the treated sewage water on the outlet side of the chemical liquid injection channel and outputs the detected value of the residual concentration of the chemical liquid component; A sewage treatment system comprising a residual concentration monitoring section that compares the estimated residual concentration of a chemical component delayed by the value delay section with the detected residual concentration of a chemical component, and notifies an alarm when the latter is excessive. Water disinfectant overfill detection device.