JP2007303908A - Method of measuring oil content in waste water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of measuring oil content in waste water capable of immediately measuring the concentration of the oil content mixed with the waste water with high precision. <P>SOLUTION: In the oil content measuring method, waste water is sampled by the sampling pipe (1) inserted in the waste water and the concentration of the oil content is measured by the oil content measuring instrument (3) provided on the downstream side of the sampling pipe (1). As the oil content measuring instrument (3), a measuring instrument equipped with a pair of the window members attached to the wall surface of the sampling pipe (1) and the light emitting part and light detecting part arranged to the outsides of the respective window members and having a structure wherein the respective window members are protruded into the sampling pipe is used. The concentration of the oil content is measured on the basis of the intensity of the light detected by the light detection part while allowing waste water to flow to the sampling pipe (1) at a specific flow speed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for measuring oil content in wastewater, and more particularly to a method for measuring oil content in wastewater, in which a trace amount of oil content mixed in wastewater is detected by an optical measuring device.

For example, orimulsion oil is a fuel oil obtained by emulsifying orinocotal and is usually used for boilers. Olimar oil is easily dissolved in water and does not generate volatile gas, and from the viewpoint of environmental protection, it is necessary to sufficiently manage leakage to waste water. As a method for measuring the concentration of the above-mentioned oral oil that has leaked from the heating pipe due to damage to the bearing part of the pump or the oil heater and mixed into the drainage, for example, the oil that is suspended in the form of fine particles in water is translucent. There has been proposed a method of measuring the concentration of the emulsion oil by image processing the belt attached to the mesh belt and attached with the emulsion oil.
JP 2003-83838 A

  By the way, in the above-mentioned measuring method, since the oil in the drainage is detected by adhering to the semi-transparent mesh belt, it is easily affected by other impurities such as dust and mud floating in the drainage, and high accuracy is obtained. There is a problem that can not be. Moreover, since a sample must be prepared with a mesh belt each time measurement is performed, there is a problem that it is difficult to adopt as a permanent system for constantly monitoring wastewater.

  The present invention has been made in view of the above circumstances, and its purpose is to reduce the concentration of oil in the wastewater without being affected by other impurities such as dust floating in the wastewater or flowing mud. It is an object of the present invention to provide a method for measuring oil content in wastewater that can be measured with high accuracy and immediately and that can continuously monitor the contamination of oil in wastewater.

  In order to solve the above problems, in the present invention, when measuring the oil concentration in the wastewater using an optical oil content measuring device that measures the oil concentration based on the intensity of the light emitted into the wastewater, The sampling tube is inserted into the pump to pump up the drainage, and the detection in the sampling tube reduces the malfunction of the measuring instrument due to floating substances on the water surface and the adhesion of dirt to the measuring instrument. By adopting a structure in which the window member that protects the light receiving part protrudes inside the sampling tube, oil is prevented from adhering to the window member, and the sample drainage is flowed at a constant flow rate in the sampling tube. The oil concentration can be measured with high accuracy while preventing the oil from adhering to the window member of the vessel.

  That is, the gist of the present invention is a method for measuring the concentration of oil mixed in waste water, the waste water is collected by a sampling pipe inserted into the waste water, and an oil content measuring device attached downstream of the sampling pipe When measuring the oil concentration by the above, as the oil content measuring instrument, a pair of window members attached to the wall surface of the sampling tube facing each other along the diameter of the sampling tube, and disposed outside one of the window members And a light emitting portion that emits light toward the other window member, and a light receiving portion that is disposed outside the other window member and senses the emitted light, and each window member includes the Using a detector with a structure protruding inside the sampling tube, measure the oil concentration based on the intensity of light detected by the light receiving unit while draining water through the sampling tube at a flow rate of 0.5 to 5 m / sec. Oil content measurement in waste water characterized by It resides in the way.

  According to the oil content measuring method of the present invention, a sampling tube is inserted into the drainage to collect the drainage as a sample, and each window member protecting the light emitting part and the light receiving part has a specific structure protruding into the sampling pipe. In order to measure the oil concentration based on the intensity of light radiated into the drainage while using drainage at a constant flow rate through the sampling pipe, other oils such as dust and mud floating on the water surface are used. It is not affected by impurities, oil does not adhere to the window of the measuring instrument, the concentration of oil in the drainage can be measured with high accuracy and immediately, and the contamination of oil into the drainage can be performed for a long time. It can be continuously monitored across.

  An embodiment of a method for measuring oil content in wastewater according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a method for measuring oil content in wastewater according to the present invention when applied to a drainage groove, and FIG. 2 shows a concept of an optical oil content measuring device applied to the present invention as a sampling tube. It is a longitudinal cross-sectional view shown by the cross section orthogonal to the length. In the following description, a method for measuring oil content in wastewater is abbreviated as “measuring method”.

  The measurement method of the present invention is a method for measuring the concentration of a minute amount of oil (particulate oil) mixed in waste water. For example, detection of origion oil in waste water discharged from various factories using boilers. Applies to The measurement location includes an oil separator part that leaks when leaked from the bearing part of the orifice transfer pump, an oil separator part that drains water that has passed through the orifice heater, and a drainage storage tank and drainage reservoir. . The present invention is applied to, for example, management of leakage of orimulsion oil. In this case, the concentration of oil to be detected (control concentration) is usually considered in the case of orimulsion oil in consideration of the influence on the environment when oil leaks. Is set to 500 ppm, preferably 100 ppm.

  In the present invention, as shown in FIG. 1, for example, the drainage is collected by the sampling pipe (1) inserted into the drainage of the drainage groove (4) laid in the factory, and attached to the downstream side of the sampling pipe. The oil concentration is measured by the oil content measuring device (3).

  When collecting the drainage as a sample by directly inserting the sampling tube (1) into the drainage, the sampling port at the tip of the sampling tube (1) is usually at a depth of 10 cm or less, preferably 20 cm or less from the water surface. And the height from the bottom is within a range of 10 cm or more. Thereby, it can reduce that other impurities, such as the dust which floated on the surface of drainage, and the mud of the drainage ditch (4) which flowed in, flow into a collection pipe (1) with a sample. And in the collection | recovery of waste_water | drain, the waste_water | drain which should be measured is suck | inhaled to a collection | recovery pipe | tube (1) using the pump (2) connected to the downstream of the collection pipe | tube (1).

  When collecting the waste water, the flow rate in the collection pipe (1) is usually set to 0.5 to 5 m / sec, preferably 1 to 3 m / sec by adjusting the flow rate of the pump (2). The reason why the flow rate in the sampling tube (1) is set in the above range is as follows. That is, when the flow rate is less than 0.5 m / sec, oil adheres to the tips of the window members (31) and (32) of the oil content measuring device (3) described later, and cannot be measured over a long period of time. . On the other hand, by setting the flow rate to 0.5 m / sec or more, it is possible to prevent oil and dirt from adhering to the window members (31) and (32). On the other hand, when the flow velocity exceeds 5 m / sec, the emulsion particles are sheared on the inner wall of the pipe and are tarred by breaking the emulsion. Therefore, as in the case where the flow velocity is small, the window members (31) and (32) Oil adheres to the surface, increasing the measurement error.

  In the present invention, the oil content in the waste water is detected in-line by the optical oil content measuring device (3) attached downstream of the sampling pipe (1), usually downstream of the pump (2). As shown in FIG. 2, the oil content measuring device (3) includes a pair of window members (31), which are arranged to face each other along the diameter of the sampling tube (1) and are attached to the wall surface of the sampling tube ( 32), a light emitting part (34) disposed outside the one window member (31) (outside the sampling tube (1)) and emitting light toward the other window member (32), and the other window A measuring instrument is used which is arranged outside the member (32) (outside the sampling tube (1)) and provided with a light receiving part (35) for detecting the emitted light.

  In the oil content measuring device (3), each of the window members (31) and (32) is composed of a two-stage cylindrical transparent glass block having an enlarged base end, and the circumference of the sampling tube (1). It attaches airtightly via a sealing material with respect to the mounting hole provided facing the surface. That is, the oil content measuring device (3) has a structure in which the tips of the window members (31) and (32) protrude into the sampling tube (1). Due to the protruding structure of the window members (31) and (32) as described above, it is possible to prevent oil from adhering to the tips of the window members (31) and (32) due to the cleaning effect due to contact with running water, and maintenance free Can be measured with high accuracy. Furthermore, the front end surfaces of the window members (31) and (32) projecting into the sampling tube (1) are formed in a bulged shape so as to prevent the adhesion of dirt containing oil more reliably. It is preferable.

  Although it does not specifically limit as a light source of a light emission part (34), Usually, light sources, such as a tungsten lamp, a halogen lamp, a semiconductor laser, and LED, are used. In the present invention, a light source capable of emitting so-called near infrared rays having a wavelength of 0.8 to 2.5 μm is particularly preferable. By using a light source in the near-infrared region as the light emitting part (34), it is possible to suppress the growth of a small amount of algae in the waste water adhering to the window members (31) and (32), and measure over a long period of time. Accuracy can be maintained.

  The light receiving unit (35) is composed of an optical-electrical converter that converts received light into an electrical signal according to the intensity thereof. As such an optical-electrical converter, usually, a photodiode that converts received light into a current according to the amount of light is used. Further, a lens (33) is disposed between the light emitting part (34) and the window member (31) in order to emit light more efficiently from the light emitting part (34) to the light receiving part (35). Also good. Further, although not shown, a condensing lens may be arranged between the window member (32) and the light receiving part (35).

  In the oil content measuring device (3), light is emitted from the light emitting section (34) to the wastewater in the sampling tube (1) through the window member (31), and the transmitted light or scattered light is transmitted to the window member (32). ) Through the light receiving unit (35). The oil concentration in the waste water is measured based on the intensity of light sensed by the light receiving unit (35). That is, the oil concentration is calculated from the intensity of transmitted light that has passed through the wastewater or the intensity of scattered light that is generated when the wastewater is transmitted.

  For example, when using scattered light in wastewater management, the oil concentration in the wastewater is measured as follows. That is, first, the apparatus is calibrated as an initial adjustment of the oil content measuring device (3). In the calibration of the oil content measuring device (3), first, light having a predetermined wavelength is emitted from the light emitting portion (34) to water not containing oil, and the intensity is detected by receiving the scattered light by the light receiving portion (35). To do. And the zero adjustment of an oil content measuring device (3) is performed so that the oil concentration in that case may be set to zero. Next, drainage in which oil is mixed to the maximum extent is prepared, and the above-mentioned light is emitted from the light emitting section (34), and the scattered light intensity is detected by the light receiving section (35). Then, the span adjustment of the oil content measuring device (3) is performed so that the oil concentration in that case becomes the maximum level. Next, from the point of managing drainage, drainage containing oil with an upper limit concentration allowed for management is allowed to flow into the sampling tube (1), and the above-mentioned light is radiated in the same manner to detect the scattering intensity. This is set as a reference value (control concentration) for the concentration of oil.

  In actual measurement, the waste water to be measured is caused to flow through the sampling tube (1), the light is emitted from the light emitting part (34) to the waste water, and the intensity of the scattered light is detected by the light receiving part (35). Then, the oil content measuring device (3) measures the oil concentration based on the intensity of the scattered light. Then, the obtained oil concentration is compared with a reference value, and it is determined whether or not the measured value exceeds the reference value. When the measured value is less than the reference value, it is determined that “no oil”, and when the measured value is equal to or greater than the reference value, it is determined that “oil is present”. Specifically, a signal obtained by the light receiving unit (35), that is, a signal converted according to the intensity of scattered light is transmitted to the data processing device, and the data processing device stores the program written in advance. Based on this, the signal is converted into a digital signal, and the obtained digital signal is compared with a reference value for discrimination processing.

  In addition, when using transmitted light, by calibrating in the same manner as when using scattered light, the oil concentration is measured based on the intensity of the transmitted light, and compared with a reference value to perform the discrimination process. Can manage wastewater as well. In the measurement by the oil content measuring device (3) as described above, the oil concentration can be measured immediately by radiating light to the waste water flowing through the sampling tube (1), and the oil content in the waste water can be continuously monitored.

  Moreover, in this invention, in the measurement of oil content, the waste water which passes the detection part of a collection pipe (1), ie, the part to which the window members (31) and (32) of the collection pipe (1) were attached, is 40- It is preferable to heat to 80 ° C. As a heating method, a method in which a tape heater is wound upstream of the window members (31) and (32) of the sampling tube (1), and a heating tank is provided on the upstream side of the oil content measuring device (3). The method etc. are mentioned. By heating the detection part to 40 ° C. or more as described above, it is possible to reduce the stickiness of the oil in the drainage and prevent the oil from adhering to the window members (31) and (32). Therefore, highly accurate measurement can be performed and maintenance is not required. Moreover, the growth of algae and microorganisms attached to the window members (31) and (32) can be suppressed.

  As described above, in the measurement method of the present invention, each window member that protects the light emitting part (34) and the light receiving part (35) by collecting the waste water as a sample by inserting the sampling tube (1) into the waste water. (31), (32) uses an oil content measuring device (3) with a specific structure protruding into the sampling tube (1), and radiates it into the drainage water while letting the drainage water flow through the sampling tube (1) at a constant flow rate. Since the oil concentration is measured by the light that has been made, the window member (31) of the oil content measuring device (3) is not affected by other impurities such as dust and mud floating on the water surface of the drainage groove (4). And oil does not adhere to (32). Therefore, the oil concentration in the waste water can be measured with high accuracy and immediately, and continuously. As a result, according to the present invention, it is possible to continuously monitor the mixing of oil into the waste water over a long period of time.

  In addition, using the oil content measuring device (3) with the structure shown in the figure, while draining water through the sampling tube (1) at a flow rate of 0.5 m / sec, using scattered light while draining in the drainage channel (4) As a result, the measurement performance was not abnormal for more than one month, and the oil content in the wastewater could be monitored. On the other hand, when the oil concentration was measured in the same manner as described above while draining water through the sampling pipe (1) at a flow rate of about 0.3 m / sec, dirt in the waste water containing the oil was removed from the oil meter (3). Attached to the window members (31) and (32), and the measurement error increased in about one week.

  On the other hand, when the oil content was measured in the same manner as described above while draining water through the sampling pipe (1) at a flow rate of about 6 m / sec, the flow to the window members (31) and (32) was reduced as in the case where the flow rate was small. The adhesion of dirt progressed, and the measurement error increased in about one week. Further, the window members (31) and (32) of the oil content measuring device (3) are attached to the sampling tube (1) so that the tip part thereof is slightly retracted from the wall surface of the sampling tube (1), and the sampling tube (1) When drainage was flown at a flow rate of 0.5 m / sec, dirt in the drainage stayed on the surface portion of the window glass (33), and the measurement error increased in two weeks.

  Further, in the oil content measuring device (3), the window members (31) and (32) having a bulging shape having a convex tip surface are adopted, and a flow rate of 0.5 to 5 m / sec is applied to the sampling tube (1). When the oil content was continuously measured in the same manner as described above while draining water in the range, the oil content in the waste water could be continuously monitored over about 5 months. Furthermore, while using the oil content measuring device (3) having the convex end surfaces of the window members (31) and (32), it is heated to 40 ° C. and fed to the sampling tube (1) at the same flow rate as above. When the measurement was continued while draining water, the oil content in the waste water was continuously monitored over the course of one year.

It is a longitudinal cross-sectional view which shows the measuring method of the oil content in the waste_water | drain based on this invention. It is a longitudinal cross-sectional view which shows the concept of the optical oil content measuring device applied to this invention in the cross section orthogonal to the length of a collection pipe | tube.

Explanation of symbols

1: sampling tube 2: pump 3: oil content measuring device 31: window member 32: window member 33: lens 34: light emitting unit 35: light receiving unit 4: drainage groove

Claims (3)

  This is a method for measuring the concentration of oil mixed in wastewater, collecting wastewater with a sampling tube inserted in the wastewater, and measuring the oil concentration with an oil meter attached downstream of the sampling tube. As the oil content measuring instrument, a pair of window members attached to the wall surface of the sampling tube so as to oppose each other along the diameter of the sampling tube, and disposed on the outside of one of the window members and toward the other window member A light emitting part that emits light and a light receiving part that is disposed outside the other window member and senses the emitted light, and each window member protrudes into the sampling tube In the drainage, the oil concentration is measured based on the intensity of light detected by the light receiving part while draining the sampling pipe at a flow rate of 0.5 to 5 m / sec. Oil content measurement method.   The oil content measuring method of Claim 1 which heats the waste_water | drain of the window member part of an oil content measuring device to 40-80 degreeC.   The oil content measuring method according to claim 1 or 2, wherein the oil content is an oil oil.