JP2000206030A - Control method for water quality - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method in which the mixture of cryptobacteria can be estimated and in which the control of a water quality is strengthened by a method wherein, on the basis of a change in the signal of a turbidimeter, particles in a specific size in water are monitored by a particle counter. SOLUTION: A particle counter 2 and a turbidimeter 3 of a transmitted and scattered light system are installed at the exit of a filtration pond 1. The particle counter 2 is a device by which the number of particles mixed with water can be measured according to a particle size, and it comprises, e.g. measuring ranges of 2 to 6 μm, 5 to 10 μm and 10 to 15 μm as measuring ranges of the particle size. When the particle counter 2 and the turbidimeter 3 are arranged at the exit of the filtration pond 1, the turbidity of the water is changed. Then, a turbid substance is confirmed by the particle counter 2. That is, when the turbidity of the water exceeds a set level, the mixture of cryptobacteria can be estimated when the counter number of particles, e.g. in 4 to 6 μm is increased according to the particle counter 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water quality management device for a filtration pond in a water purification plant, and more particularly to a water quality management device suitable for monitoring turbidity containing biological particles.

[0002]

2. Description of the Related Art Water purification equipment includes water landing, sedimentation, and filtration as water purification processes, and washing and drainage, sedimentation and sludge treatment, and sludge treatment equipment as drainage and sludge removal processes. The water purification step is a step of removing various fine particles, microorganisms, bacteria and the like contained in the raw water to make the water usable as drinking water. As a process for removing these, a process of chemical injection precipitation → rapid filtration is employed.

FIG. 5 is a diagram showing a general water treatment process from water intake → purified water → drainage. In FIG. 5, water taken from a river or lake into a sedimentation basin is sent to a landing well by a pump and further sent to a rapid stirring / slow stirring tank. Next, the water is sent to the rapid filtration pond via the chemical sedimentation basin, and the filtered water is provided to the user by the water distribution pump via the chlorine mixing pond and the water purification pond.

[0004]

Since the above-mentioned rapid filtration pond is the last stage of removing suspended substances in the water purification treatment process, the turbidity of this filtration pond is conventionally controlled to about 2 in accordance with JIS-K0101. Have been. By the way, Cryptosporidium bacteria (hereinafter simply referred to as Crypto bacteria), which are parasitic protozoa living in the body fluids and cells (mainly intestinal tract) of animals, are mixed into tap water treated and managed in recent years. An accident occurred.

[0005] The size of this cryptobacterium is about 4 to 6 µm, and it is extremely resistant to chlorine sterilization (about 6 to 6 µm of Escherichia coli).
90,000 times). It is said that there are 800 to 14,000 Crypto bacteria per liter in raw sewage. Oral infection with this crypt bacterium causes severe watery diarrhea, abdominal pain and nausea. If the immunity of the infected person is reduced, it becomes fatal.

Therefore, the Ministry of Health and Welfare instructs the turbidity at the outlet of the rapid filtration tank to be 0.1 degrees or less as a provisional measure. However, since the refractive index of biological particles is close to that of water and scattered light is difficult to obtain, there is a problem that scattered light cannot be measured as turbidity with a scattered light measuring instrument. When mixed, there is a problem that accurate measurement of turbidity including the substance cannot be performed.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a water quality control device capable of performing measurement even when a substance having a refractive index close to that of water is mixed.

[0008]

In order to achieve the above object, according to the present invention, there is provided a water quality management device for a filtration pond in a water treatment plant, wherein the turbidity at the outlet of the filtration pond is controlled. Using a turbidity meter and a particle counter,
The apparatus is characterized in that particles of a specific size in water are monitored by a particle counter based on a change in a signal of the turbidimeter. According to a second aspect of the present invention, in the water quality management device according to the first aspect, the measurement water to be measured is branched and transmitted through a filter, and the measurement water transmitted through the filter is used as a zero calibration liquid for the turbidity meter. Features.

According to a third aspect of the present invention, in the water quality management device for a filtration pond in a water purification plant, a first particle counter is provided at an entrance of the filtration pond, and a second particle counter and a turbidity meter are provided at an exit of the filtration pond. Features.

According to a fourth aspect of the present invention, in the water quality management device for the filtration ponds in the water purification plant, the first entrances to the plurality of filtration ponds are provided.
A second particle counter is provided at the particle counter and at the outlet, and the intake of water from the filtration pond is continued or stopped based on the measurement result of the counted particles. According to a fifth aspect of the present invention, in the water quality management device according to the first aspect, when the particle counter counts particles having a size of 4 to 6 μm, it is estimated that the bacterium is Cryptosporidium.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of an embodiment according to claims 1 and 2 of the present invention. In this embodiment, a particle counter 2 and a turbidity of a transmitted scattered light system are provided at an outlet of a filter pond 1 shown in FIG. A total of 3 are provided. The particle counter 2 is a device capable of measuring the number of particles mixed in water for each particle diameter.
m, 5 to 10 μm, and about 10 to 15 μm. Such devices are commercially available.

The turbidimeter 3 uses a scattered light type as shown in FIG. In FIG. 2, light from a light source 10 passes through a measurement tube 11 through which a sample flows, and reaches a scattered light photovoltaic cell (photoelectric converter) 12 and a transmitted light photocell (photoelectric converter) 13 which are arranged to face each other. . The scattered or transmitted light is converted into an electric signal by the respective photoelectric converters 12 and 13, amplified by the amplifiers 14 a and 14 b, and the total turbidity is calculated by the proportional calculator 15.
Amplified at 6 and extracted as an output of, for example, 4 to 20 mA.

FIG. 3 shows a schematic configuration including the turbidity meter 3, and one end of a pipe 19 is connected to an outlet of a filtration pond. The sample passes through the turbidimeter 3 through the defoaming tank 20, and is drained through the fixed throttle 24. The indicator 23 has a turbidity measurement range of about 0 to 0.2 degrees.

In the calibration mode, the sample passes through the turbidimeter 3 through a 1 μm mesh filter 21 and a 0.1 μm mesh filter 22. The zero point is calibrated with clean water that has passed through this filter. By adopting a piping configuration including such a turbidity meter, turbidity at a low concentration can be accurately measured.

According to the configuration shown in FIG. 1, a particle counter 2 and a turbidity meter 3 are arranged at the outlet of the filtration tank, and when there is a change in turbidity, the turbidity substance is confirmed by the particle counter 2. That is, when the turbidity exceeds the set level, the particle counter 2
If the count of particles having a particle size of 4 to 6 μm increases, it is possible to infer that Cryptobacterium is mixed.

FIG. 4 is a schematic block diagram of an embodiment according to claim 3 of the present invention, in which a second particle counter 4 is installed at the inlet side of the filtration pond 1 shown in the water quality control device having the configuration shown in FIG. Things.

According to such a configuration, the life of the filtration pond can be monitored in addition to the measurement of the cryptobacterium described with reference to FIG. That is, the change in the particle size on the inlet side and the outlet side is monitored, and when the size of the particles on the outlet side becomes larger than the size of the particles on the inlet side, it can be inferred that the function of the filtration pond is reduced. .

Generally, a large number of filtration ponds are provided in parallel with a water purification plant, and these are subjected to backwashing and the like at regular intervals including a suspension period to manage the filtration ponds.
In such a management, it is not possible to quickly respond to a management including a suddenly occurring crypt bacterium and the like. Claim 4 of the present invention
According to the above, a first particle counter is provided at the entrance of the plurality of filtration ponds, and a second particle counter is provided at the exit, and the intake of water from the filtration basin is configured to be continued or stopped based on the measurement result of the counted particles. In addition, finer filtration ponds can be managed.

It is to be noted that the above description of the present invention has been presented by way of explanation and illustration only of particular preferred embodiments. Thus, it will be apparent to one skilled in the art that the present invention may be modified or modified in many ways without departing from its essentials. For example, the arrangement of the particle size counter 2 and the turbidity meter 3 at the outlet of the filtration tank may be reversed. In this embodiment, a transmission scattering turbidity meter is used as the turbidity meter. However, since the estimation of Crypto bacteria is performed by a particle counter, another type of turbidity meter may be used. The scope of the present invention, which is defined by the description in the appended claims, is intended to cover alterations and modifications within the scope.

[0020]

As described above, according to the present invention, the turbidity meter and the particle counter are used as a means for managing the turbidity at the outlet of the filtration pond in the water quality control device of the filtration pond in the water treatment plant. Since the particle counter is configured to monitor particles of a specific size in water based on a change in the signal of the meter, the turbidity may exceed a set level, or the count of the particle counter may be a specific size (2 to 4 μm). When C. elegans is detected, contamination of Crypto bacteria can be estimated.

Further, a first particle counter and an outlet second particle counter are provided at the inlets of the plurality of filtration ponds, and the intake of water from the filtration ponds is continued or stopped based on the result of counting the counted particles. In addition, finer filtration ponds can be managed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an embodiment according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a general transmission scattered light turbidimeter.

FIG. 3 is a schematic configuration diagram showing an example of a pipe of a general transmission scattered light turbidimeter.

FIG. 4 is a schematic configuration diagram showing another example of the embodiment according to the present invention.

FIG. 5 is a diagram showing a general water treatment process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration pond 2, 4 Particle counter 3 Turbidity meter 10 Light source 11 Measuring tube 12 Photocell for scattered light (photoelectric converter) 13 Photocell for transmitted light (photoelectric converter) 14, 16 Amplifier 15 Ratio calculator 19 Piping 20 Defoaming Vessel 21, 22 Filter 23 Indicator 24 Fixed squeezing

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 15/06 G01N 33/18 A 33/18 Z G06M 7/00 301A G06M 7/00 301 B01D 35/14 102 (72) Inventor Ken Takeshi 2-9-32 Nakamachi, Musashino City, Tokyo Inside Yokogawa Electric Corporation

Claims (5)

[Claims] In a water quality control device for a filtration pond in a water purification plant, a turbidity meter and a particle counter are used as means for managing the turbidity at the outlet of the filtration pond, and the water in the water is identified based on a change in the signal of the turbidity meter. A water quality management device characterized in that particles having a size of are monitored by a particle counter. 2. The water quality control device according to claim 1, wherein the measurement water to be measured is branched and transmitted through a filter, and the measurement water transmitted through the filter is used as a zero calibration liquid for the turbidity meter. . 3. A water quality management device for a filtration pond in a water purification plant, wherein a first particle counter is provided at an entrance of the filtration pond, and a second particle counter and a turbidity meter are provided at an exit of the filtration pond. Management device. 4. A water quality management device for a filtration pond in a water purification plant, wherein a first particle counter is provided at an inlet of the plurality of filtration ponds, and a second particle counter is provided at an outlet of the plurality of filtration ponds. A water quality management device, characterized in that the intake of water is continued or stopped. 5. The water quality control device according to claim 1, wherein when the particle counter counts particles of 4 to 6 μm, it is estimated that the bacterium is Cryptosporidium.