JP2017037033A - Method for cleaning surface of detection unit of light receiver/emitter installed on water passing-type turbidimeter with scattered light method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide cleaning method that efficiently cleans a detection unit while continuously measuring the turbidness of processed water of industrial waste water by using a water passing-type turbidimeter with a scattered light method and can prevent deterioration in measurement accuracy.SOLUTION: A cleaning method is for cleaning the surface of a detection unit 17 containing a light receiver and a light emitter installed inside the detection unit of a turbidimeter with a scattered light method when measuring the turbidness of processed water of industrial waste water by using the passing water-type turbidimeter with a scattered light method. The cleaning method emits cleaning water to the surface of the detection unit with an inclination angle 60-80° to the normal of the surface of the detection unit.SELECTED DRAWING: Figure 1

Description

  The present invention is used to measure the turbidity of treated water that has been treated to discharge wastewater discharged from various equipment installed in various factories (hereinafter referred to as factory wastewater) to the outside of the factory. The present invention relates to a method for cleaning the surface of a detection unit of a light-receiving / emitting device disposed in a turbidimeter that detects the amount of suspension in water.

  Since various substances are dissolved in the factory effluent, when discharging the factory effluent outside the factory, it is necessary to remove these substances and purify the water quality to meet the effluent standards. As a technique for removing substances dissolved in factory wastewater (hereinafter referred to as dissolved substances), a technique for separating and removing dissolved substances by adding a neutralizing agent (that is, adjusting pH) or adding a flocculant has been put into practical use. Yes. An example of the processing process of the factory waste water is shown in FIG.

  In the treatment process shown in FIG. 3, the factory waste water 1 is guided to the raw water tank 2 from each facility installed in the site and temporarily stored. And the factory waste water 1 is supplied from the raw water tank 2 to the mixing tank 3a in the neutralization equipment 3, and the dissolved substance in the factory waste water 1 is uniformly dispersed. Next, the neutralizing agent 10 is added in the primary neutralizing tank 3b and the secondary neutralizing tank 3c, respectively, and the flocculant 11 is further added in the coagulating tank 3d to coagulate the dissolved substance, followed by precipitation. It supplies to the tank 4, and the aggregated large-sized dissolved substance is precipitated. The dissolved substance 9 (hereinafter referred to as “precipitate”) coagulated and precipitated here is discharged from the bottom of the precipitation tank 4. The precipitate 9 is disposed after being treated as industrial waste.

  In the industrial waste water 1 from which the precipitate 9 has been removed in this way, since fine particles of the agglomerated dissolved substance are floating, filtration is performed to remove the fine particles (hereinafter referred to as suspended substances). It is supplied to the tank 5. The factory waste water 1 from which suspended substances have been removed by filtration is temporarily stored as treated water 30 in the storage tank 6 and further discharged through the drain groove 7 to the outside of the factory.

  At this time, if appropriate precipitation treatment or filtration treatment is not performed, the factory wastewater 1 mixed with suspended substances may be discharged from the drainage channel to the outside. Therefore, in order to confirm that a series of treatment steps are properly performed, the turbidity (that is, the amount of suspended solids) of the treated water 30 is measured by using the turbidimeter 8 in the drain groove 7. Yes. When the measured value of turbidity exceeds a preset reference value, the discharge of the treated water 30 is stopped, and the neutralization equipment 3 and the sedimentation tank 4 are used in order to appropriately perform the precipitation treatment and the filtration treatment. Adjust operating conditions.

  In measuring the turbidity of the treated water 30 in the drain groove 7, an immersion type turbidimeter 8 has been widely used conventionally. The immersion-type turbidimeter 8 is for continuously measuring the turbidity by immersing the turbidimeter 8 in the treated water 30 flowing through the drainage groove 7. Since lime is used as a neutralizing agent for adjusting pH in the process of treating the industrial waste water 1, fine Ca compounds are suspended in the treated water 30, and such Ca compounds are contained in the turbidimeter 8 It may adhere to the surface of the detection unit, and if left unattended, it will contaminate the surface of the detection unit, scatter the light at the light receiving / emitting device of the turbidimeter 8 and prevent proper turbidity measurement. There is. Therefore, the surface of the detection part of the turbidimeter 8 needs to be washed at an appropriate timing. The cleaning operation is performed by a procedure in which an operator takes out the turbidimeter 8 from the drainage groove 7, cleans the dirt of the detection unit with hydrochloric acid or the like, and immerses it again in the drainage groove 7.

  Such a work is a human-powered work that is regularly performed by an operator who visits the site. Moreover, since the operation | work which removes the turbidimeter 8 from the drainage groove 7, and also attaches is performed around the opening part provided in the drainage groove 7, the problem of a safety surface also arises.

  Patent Document 1 discloses a method of cleaning a detector by injecting compressed gas onto a detection portion of an immersion type detector. However, in the case of a turbidimeter that has a light emitting part such as a scattered light turbidimeter and a light receiving part that detects the scattered light, it is necessary to suppress the influence of the background as much as possible. In many cases, the water flow type is formed and a turbidimeter is installed therein, and it is not preferable to blow a large amount of compressed gas into the pipe flow path.

  As described above, in the conventional technique, a cleaning technique capable of continuously and efficiently cleaning the detection unit of the water-flow type scattered light turbidimeter and preventing a decrease in measurement accuracy is still established. Not.

JP 2005-211858 JP

  The present invention eliminates the problems of the prior art and efficiently detects the turbidity while continuously measuring the turbidity of the treated water of the factory effluent using a water flow type scattered light turbidimeter. It aims at providing the washing | cleaning method which can wash | clean and prevent the fall of a measurement precision.

  This inventor examined the technique which can wash | clean the surface of a detection part effectively in a water flow type scattered light system turbidimeter. And it paid attention to the technique which wash | cleans using washing water, without using gas.

  Therefore, while continuously measuring the turbidity, various washing water was sprayed to the detection unit under various conditions, and an experiment was conducted to investigate the progress of washing and the change in measurement accuracy. As a result, the present inventors have found that purified water (for example, factory water, tap water, etc.) is inexpensive and easily available, and is effective for cleaning the detection unit.

  When cleaning is performed by spraying the surface of the detection unit under appropriate conditions using purified water, the suspension adhering to the surface of the detection unit is mechanically separated by the dynamic pressure of the purified water, and the surface of the detection unit can be cleaned. Then, this inventor examined the influence which the purified water sprayed had on the measurement precision of turbidity. As a result, it was found that with a water flow type scattered light turbidimeter, stable water can be measured if purified water is jetted under appropriate conditions.

The present invention has been made based on such knowledge.
That is, when detecting the turbidity of the treated water of the factory effluent using a water flow type scattered light turbidimeter, the present invention provides a surface of the detection unit in which the light receiving / emitting device of the scattered light turbidimeter is built. In the cleaning method for cleaning the surface of the detection unit, the surface of the detection unit is provided with an inclination angle of 60 ° to 80 ° with respect to the normal of the surface and sprays cleaning water onto the surface.

  According to the present invention, the turbidity of treated water that has been treated by neutralization treatment, precipitation treatment, filtration treatment, etc., of suspended matter or dissolved matter in factory wastewater is continuously obtained using a water-flow type scattered light turbidimeter. Since the surface of the detection part of the measuring instrument can be efficiently cleaned and the measurement accuracy can be prevented from being lowered while the measurement is performed, it is possible to achieve a remarkable industrial effect.

It is sectional drawing which shows the example of the water flow type | mold scattered light type turbidimeter to which this invention is applied. It is sectional drawing which expands and shows the detection part and light source part in FIG. It is a flowchart which shows an example of the process of a factory wastewater. It is a graph which shows transition of the measurement result of turbidity.

  An example of a water flow type scattered light turbidimeter to which the present invention is applied is shown in FIG. The water flow type scattered light turbidimeter has a cylindrical container 13 (hereinafter referred to as a cylindrical container), and the treated water 30 in a drainage groove (not shown) is pumped (not shown). Sucked up and supplied into the cylindrical container 13 from the inlet 12 at all times. Inside the cylindrical container 13, a partition wall 14 is provided from the upper surface of the cylindrical container 13 to a position lower than the inlet 12, and the partition 14 passes through the inside of the cylindrical container 13 on the inlet 13 side flow path 13 a ( Hereinafter, the flow path is divided into an inflow side flow path) and a flow path 13b on the discharge port 15 side (hereinafter referred to as a discharge side flow path).

  The treated water 30 supplied from the inlet 12 into the cylindrical container 13 flows downward along the partition wall 14 in the inflow side flow path 13a, passes through the gap between the lower end of the partition wall 14 and the bottom surface of the cylindrical container 13, Further, it flows upward in the discharge side flow path 13b and is returned to the drainage groove from the discharge port 15 again. In addition, the arrow in FIG. 1 shows the flow of the treated water 30.

  In the inflow channel 13a, the treated water 30 flows downward, while the bubbles 16 in the treated water 30 rise upward and are separated. Accordingly, since the bubbles 16 do not flow into the discharge side flow path 13b, it is possible to prevent a decrease in measurement accuracy in the turbidity measurement described later.

  The detection unit 17 includes a light emitter 18 and a light receiver 19, and is attached so as to measure the turbidity of the treated water 30 in the discharge side flow path 13b. For example, as shown in FIG. 1, the detector 17 is inserted from the outer wall of the inflow side flow path 13a of the cylindrical container 13 to penetrate the partition wall 14, and the light emitter 18 and the light receiver 19 are disposed in the discharge side flow path 13b. For example, the turbidity can be measured in the discharge side channel 13b. Or although illustration is abbreviate | omitted, you may attach the detection part 17 to the outer wall of the discharge side flow path 13b.

  When the turbidity is measured, light is emitted from the light emitter 18, and the light is reflected by the suspended substance floating in the treated water 30 to be received by the light receiver 19. In this way, suspended substances are detected, and further arithmetic processing is performed to measure turbidity.

  As already described, since the bubbles 16 do not exist in the industrial waste water 1 in the discharge side flow path 13b, the turbidity can be measured accurately by measuring the turbidity of the treated water 30 in the discharge side flow path 13b. Decline can be prevented.

  Here, FIG. 2 shows an enlarged view of the light emitter 18, the light receiver 19, and the periphery thereof in FIG. To do.

  The light emitter 18 emits light toward the treated water 30 from the surface 17a at the tip of the turbidimeter detector 17, and the light receiver 19 receives the light reflected from the treated water 30 side. When there is no suspended matter that reflects light in the treated water 30, almost no reflected light is received by the light receiver 19.

  However, when the suspended matter 20 is present in the treated water 30, the light 18a irradiated from the light emitter 18 (hereinafter referred to as irradiated light) is reflected by the suspended matter 20 as shown in FIG. As shown in FIG. Therefore, the concentration of the suspended solid 20 can be measured by keeping the irradiation light 18a constant and measuring the intensity of the reflected light 19a. As a result, when the concentration of the suspended matter 20 in the treated water 30 increases, the turbidimeter can detect the phenomenon and detect that an abnormality has occurred in the treatment process of the factory waste water 1. Can do.

  However, if the surface 17a of the detection unit including the light emitter 18 and the light receiver 19 becomes dirty, an error occurs in the measurement value.

  Therefore, in the present invention, in order to eliminate the contamination of the surface 17a of the detection unit 17, with the detection unit 17 attached to the cylindrical container 13, water flow to the cylindrical container 13 is temporarily stopped, and the cylindrical container 13 is stopped. Drain the water inside. As a result, the surface 17a of the detection unit 17 is exposed to the air, and cleaning water is sprayed from the cleaning water nozzle 21 onto the surface 17a of the detection unit 17 to remove dirt adhered to the surface 17a of the detection unit 17. To do.

  The washing water used is preferably purified water (for example, factory water, tap water, etc.). The reason is that, in a wastewater treatment facility of a factory that is a target facility of the present invention, a water purification pipe is generally introduced and it is easy to use. Moreover, the treated water 30 after waste water treatment can also be used. In the present invention, as will be described later, the cleaning water is effectively sprayed onto the surface 17a of the detection unit 17, thereby mechanically removing the dirt that adheres to and accumulates on the surface 17a of the detection unit 17. The treated water 30 can be used if it can be sprayed under predetermined conditions. In this case, there is an advantage that the amount of discharged water is not increased.

  If the angle θ formed by the washing water injection direction 21a and the normal direction of the surface 17a of the detection unit 17 is too small, the irradiation light 18a emitted from the light emitter 18 is reflected by the washing water nozzle 21 and is received by the light receiver 19. Since the light is received, the accuracy of measuring the concentration of the suspension may be deteriorated. When the angle θ is too large, it is difficult to effectively clean the surface 17a of the detection unit 17 and the contamination cannot be removed. Therefore, the angle θ is preferably 60 to 80 °.

  Further, when the cleaning water injection speed is too low, the dirt on the surface 17a of the detection unit 17 cannot be removed. If the injection speed is too high, the detection unit 17 may be damaged. Accordingly, the jetting speed of the cleaning water is preferably 5 to 20 m / sec at the nozzle port at the tip of the cleaning water nozzle 21. The distance that the tip of the washing water nozzle 21 and the sprayed water reach the surface 17a of the detection unit 17 is preferably about 5 to 20 cm.

  Furthermore, when the flow rate of the washing water is too small, the dirt on the surface 17a of the detection unit 17 cannot be removed. When the flow rate is too large, the impact on the surface 17a of the detection unit 17 is strong and may cause damage, so the flow rate of cleaning water is preferably 10 to 30 L / min.

  As described above, the cleaning method of the present invention can efficiently clean the detection unit 17 of the turbidimeter that measures the turbidity of treated water, and can prevent a decrease in measurement accuracy. In addition, since it is a water flow type that pumps up factory wastewater in the drainage channel and supplies it to the scattered light method turbidimeter, it is possible to install the scattered light method turbidity meter in a flat place away from the drainage channel At the same time, the surface 17a of the detection unit 17 can be cleaned by jetting cleaning water from the cleaning water nozzle 21 that is constantly installed in the cylindrical container 13, so that automatic cleaning by sequencer control or the like is possible. Become. For this reason, in order to clean the surface 17a of the detection unit 17, it is possible to eliminate on-site work such that an operator goes to the drainage groove to take out and attach the turbidimeter, and the safety of the cleaning work is improved.

  The treated water of the factory wastewater is sucked up from the drainage channel of the steel factory and supplied to the water flow type scattered light turbidity meter shown in Fig. 1, and the turbidity indicator is periodically cleaned while the receiver is cleaned. An experiment was conducted in which the amount of suspended solids (mg / L) was continuously measured for 40 days. This is an invention example. In the experiment of this invention example, tap water was used as washing water, the flow rate was 13 L / min, the injection speed at the nozzle port at the tip of the washing water nozzle was 8 m / sec, the angle θ was 75 °, and sequencer control was performed. Sprayed every 12 hours for 5 minutes. For this cleaning, water flow to the cylindrical container 13 was temporarily stopped and the measurement was interrupted for 10 minutes.

  For comparison, the cleaning water nozzle of the water flow type scattered light turbidimeter shown in FIG. 1 is not used (that is, the surface 17a of the detection unit 17 is not cleaned), and the treated water is the same as the invention example. An experiment was conducted in which the amount of suspended material was continuously measured for 40 days. This is referred to as Comparative Example 1.

  In addition, a conventional immersion type turbidimeter was installed in the drainage ditch and an experiment was conducted to measure the amount of suspended matter in the treated water as in the invention example for 40 days. This is referred to as Comparative Example 2. In the experiment of Comparative Example 2, the worker took out the immersion type turbidimeter from the drainage groove once a day and cleaned the surface 17a of the detection unit 17 with an aqueous hydrochloric acid solution. The total operation time of the cleaning operation was 2 hours / time, and it took 10 minutes for the immersion turbidimeter to be removed from the drainage channel during the cleaning operation and cleaned and returned to its original state. The measurement of the amount of suspended solids was stopped for 10 minutes.

  In each experiment, the transition of the average value of the measurement data obtained on each day is shown in FIG. However, in Invention Example 1, the inside of the cylindrical container 13 was drained at the time of cleaning, the cleaning was performed, and the measurement was interrupted for 10 minutes until the water was passed again.

  As shown in FIG. 4, in the inventive example, turbidity (that is, the amount of suspended solids) could be stably measured over 40 days. This means that the suspended substance did not accumulate on the surface 17a of the detection unit 17 as a result of sufficiently washing the light receiver.

  On the other hand, in Comparative Example 1, the turbidity started to increase in about one week from the start of the experiment and was saturated in about two weeks, so the experiment was stopped. This means that the scattered light turbidimeter has detected the suspended matter deposited on the surface 17a of the detection unit 17 and calculated the turbidity based on the suspended matter. Therefore, the measurement result of Comparative Example 1 has a large error with respect to the true turbidity of the factory effluent.

  In Comparative Example 2, the measurement result of turbidity was equivalent to that of the invention example. However, as already explained, in Comparative Example 2, the time for stopping the measurement occurred 10 minutes per day.

  In Comparative Example 2, the cleaning operation is performed by a procedure in which an operator removes the turbidimeter from the drainage groove, cleans the dirt on the surface 17a of the detection unit 17 with hydrochloric acid, and soaks it again in the drainage groove. It was. This series of work not only has a heavy load, but also works on the drainage channel, so there is a problem from the viewpoint of safety. Moreover, this cleaning operation tends to cause variations in the cleaning effect depending on the level of skill, and it has been impossible to eliminate human errors such as an error in the recovery position of the detector and forgetting to turn on the switch. On the other hand, in the invention example, since the washing water was jetted by the sequencer control, the surface 17a of the detection unit 17 could be washed unattended.

1 Factory drain 2 Raw water tank 3 Neutralization equipment
3a Mixing tank
3b Primary neutralization tank
3c Secondary neutralization tank
3d Coagulation tank 4 Sedimentation tank 5 Filtration tank 6 Storage tank 7 Drainage channel 8 Turbidimeter 9 Precipitate
10 Neutralizing agent
11 Flocculant
12 Inlet
13 Tubular container
13a Inlet side flow path
13b Discharge side flow path
14 Bulkhead
15 outlet
16 bubbles
17 Detector
17a Detector surface
18 Light emitter
18a Irradiation light
19 Receiver
19a Reflected light
20 Suspended material
21 Washing water nozzle
21a Injection direction
30 treated water

Claims (1)

  Cleaning that cleans the surface of the detector unit that contains the light emitter / receiver of the scattered light turbidimeter when measuring the turbidity of treated water from factory effluents using a water flow type scattered light turbidimeter In the method, the method for cleaning the surface of the detection unit is characterized in that cleaning water is sprayed onto the surface with an inclination angle of 60 to 80 ° with respect to the normal of the surface.

Images