JP2002035503A - Turbid water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbid water treatment apparatus small in its installation area, large in treatment quantity, obtaining clean treated water and preventing the clogging of a raw water passage. SOLUTION: In the turbid water treatment apparatus constituted so that raw water is transferred to a separation tank while a flocculant is added to raw water to form flocs to remove a suspended substance from raw water, an inner tank 31 is provided in the separation tank 15 (outer tank 30) so that the upper edge 31a of the inner tank 31 becomes lower than the upper edge 30a of the outer tank 30 and raw water is supplied into the inner tank 31 from the side surface of the lower part thereof in a tangential direction. Flocs are formed in the inner tank 31 but, since the inner tank 31 is smaller than the whole of the separation tank 15, flocs are easily formed in the early stage and the growing speed thereof is also high. Since there is a distance (h) between the upper edge 31a of the inner tank and the upper edge 30a of the outer tank, even if a part of flocs exceeds the upper edge of the inner tank to rise, flocs sediment before reach the upper edge 30a of the outer tank and the flocs (or the suspended substance) do not almost flow out of the separation tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbid water treatment device for clarifying turbid water generated from a civil engineering construction site or the like to such an extent that it can be discharged to a river or the like.

[0002]

2. Description of the Related Art Turbid water treatment of industrial wastewater and river water is an important issue for protecting the natural environment, and various devices have been developed so far. Add coagulant to raw water,
A coagulation sedimentation apparatus for introducing a suspension from the bottom of a coagulation sedimentation tank, stirring, floc formation and sedimentation separation is widely used.

[0003] Since a large amount of turbid water is generated at a civil engineering construction site or the like, it is necessary to treat it in real time. Therefore, one of the important issues in turbid water treatment is to improve its treatment efficiency. Japanese Patent Publication No. 5-18601 discloses an apparatus in which a plurality of rows of composite grooves for performing coagulation and sedimentation are arranged in a coagulation and sedimentation tank.

[0004]

In the apparatus described in Japanese Patent Publication No. Hei 5-18601, a plurality of rows of compound grooves for performing coagulation and sedimentation are arranged in parallel in the coagulation and sedimentation tank. There was a problem. The present invention has been made in order to solve such a problem, and the purpose thereof is to increase the area of the installed device without increasing the area.
Moreover, it is to provide a turbid water treatment device with high treatment efficiency.

[0005]

A turbid water treatment apparatus according to the present invention, which has been made to solve the above-mentioned problems, comprises adding a flocculant to raw water, transferring the flocculant to a separation tank, and forming flocs there, thereby forming a floc from raw water. In the turbid water treatment apparatus for removing suspended matter, an inner tank is provided inside the separation tank, and the upper edge of the inner tank is lower than the upper edge of the separation tank, and the raw water is supplied to the lower part of the inner tank. It is characterized in that it is supplied from the side.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a flocculant is added to raw water containing a suspension, and is transferred to a separation tank. In the separation tank, the suspension in the raw water is flocculated by the flocculant to form flocs. As the raw water passes through this floc, the flocculated suspension is captured by the flocs, removing the suspension from the raw water,
Flock grows and the filtration performance of the suspension is further improved.

In the turbid water treatment apparatus according to the present invention, an inner tank is provided inside the separation tank, and raw water is supplied from a lower part thereof. Therefore, flocs are mainly formed in the inner tank.
Since the inner tank is smaller than the entire separation tank, there is an effect that flocs are easily formed in the initial stage. In addition, the growth rate of floc is also high. And since there is a distance between the upper edge of the inner tank and the upper edge of the separation tank, even if a part of the floc rises beyond the upper edge of the inner tank, it sinks before reaching the upper edge of the separation tank. Therefore, the flocks (or suspended matter) are prevented from flowing out of the separation tank.

In the turbid water treatment apparatus, the raw water is supplied from the side below the inner tank. As a result, the supplied raw water rises while rotating (spiral movement) in the inner tank, so that the contact time and distance with the floc in the inner tank can be increased, and the suspended solids can be increased. Will be better separated.

[0009]

FIG. 1 shows an overall view of an example of a turbid water treatment apparatus embodying the present invention. The turbid water treatment apparatus of this embodiment is provided with water tanks such as a raw water tank 11, a reaction tower 14, a separation tank 15, and a discharge water tank 16 in the order of treatment.

As shown in FIG. 2, raw water generated at a civil engineering construction site or the like is first stored in a raw water tank 11. Raw water in the raw water tank 11 is pumped to the raw water flow path 12 by the raw water transfer pump 20. Raw water from civil engineering construction sites is often mixed with cement-based turbidity. In this case, the cement-based turbidity can gradually accumulate on the inner wall of the raw-water flow path 12 to narrow the flow path. There is. Therefore, in this device, the raw water flow path 1
2 is provided with an electromagnetic flow meter 22, and the flow rate control unit 21 controls the rotation speed of the raw water transfer pump 20 by an inverter so that the flow rate in the flow path 12 becomes constant.
As a result, narrowing and blockage of the raw water flow path 12 are prevented, and a reduction in the throughput of the entire turbid water treatment system is prevented.

The raw water discharged from the raw water tank 11 is mixed with polyaluminum chloride (PA) as an inorganic coagulant.
C) and carbon dioxide (CO ₂ ) as a pH neutralizer. The polyaluminum chloride stored in the PAC tank 23 is injected into the flow channel 12 after the addition amount is adjusted. The gas extracted from the carbon dioxide by adjusting the pressure appropriately from the cylinder 26 by the controller 24 is supplied to the flow path 1.
Injection is made in two separate locations. After these are added, the raw water is sufficiently stirred in the line mixer 13 and sent to the reaction tower 14. In the reaction tower 14, the neutralization reaction is mainly promoted. The pH of the raw water in the reaction tower 14 is detected by a pH sensor 46, and the data is output from a raw water pH indicator 47 (FIG. 4) as a control signal for carbon dioxide injection. This data is used for controlling the automatic valve opening and closing of the CO ₂ controller 24, that is, for controlling the timing of injecting carbon dioxide into the raw water.

The raw water neutralized in the reaction tower 14 is supplied to a separation tank 15
In the vicinity of the outlet of the reaction tower 14, the polymer flocculant prepared in the polymer dissolution tank 27 is injected into the raw water.

[0013] As shown in FIG.
And the inner tank 31 have a double structure.
It is located in the center of the bottom of the zero. Upper edge 31a of inner tank 31
Is sufficiently lower than the upper edge 30a of the outer tub 30, and a sufficient height (h) is secured between the two.

Raw water from the reaction tower 14 is tangentially injected from the side of a cylindrical injection part 34 provided at the bottom of the inner tank 31 and rises spirally inside the inner tank 31. A condensed floc layer is formed on the upper part of the inner tank 31, and the turbidity in the raw water contacts the concentrated floc layer to promote a coagulation reaction and separate into water and floc.
Thereby, the floc layer further grows, and the turbidity trapping / aggregating performance is improved.

The water from which the turbid matter has been removed by passing through the floc layer of the inner tank 31 further rises in the separation tank 15 (outer tank 30), and passes through the overflow weir at the upper edge 30a of the outer tank to discharge water. Flow out to 16. As described above, since a sufficient distance (h) is provided between the upper edge 31a of the inner tank 31 and the upper edge 30a (overflow weir) of the outer tank, the floc layer at the start of operation or the like is unstable. Even when the flock floats above the inner tank 31 by riding the flow of the raw water at any time, the floating flock does not immediately flow out of the separation tank 15 and sinks in the outer tank 30.

When the concentrated floc in the inner tank 31 grows and becomes excessive, it overflows from a slit 37 provided slightly below the upper edge 31a of the inner tank 31, as shown in FIG. The overflowing flocks are overflowed to the bottom of the outer tub around the inner tub 31 without being raised by the annular plate 38 provided on the upper portion of the slit 37. After floating on the upper portion of the inner tank 31 as described above, a part of the floc settled in the outer tank 30 also settles on the bottom of the outer tank 30 around the inner tank 31. Accordingly, at an appropriate time, the stirring plate 32 inside the inner tank and the scraping blade 33 around the bottom of the outer tank are rotated by the motor M (these are attached to the same shaft and both are driven by the motor M). ), The surplus flocks are dropped from the slit 37 into the sludge reservoir 35, and are discharged to a slurry tank (not shown) by the sludge pulling pump 36.

On the other hand, when raw water of low concentration is treated for a long time,
The floc layer becomes unstable. In this case, the sludge (excess floc) in the sludge reservoir 35 is returned to the reaction tower 14 before the injection of the polymer flocculant by the sludge withdrawing pump 36, and is circulated again to the inner tank 31 to promote the formation of the floc layer. ing.

The treated water (treated water) flowing out of the overflow weir 30a of the separation tank 15 enters a sampling tank 40 provided above the discharge water tank 16 as shown in FIG. And pH are measured by the respective sensors 41, 42. The treated water overflowing from the sampling tank 40 falls into the discharge water tank 16 and is stored there. The stored treated water is discharged to the outside at an appropriate timing.

The processing measured in the sampling tank 40
The turbidity and pH data of the water are supplied to the turbidity converter 43 and
To the water quality recorder 45 via the pH indicator 44
Sent. Also, the instantaneous flow rate can be obtained from the electromagnetic flow meter 22 (FIG. 2).
Is sent to the water quality recorder 45. Water quality recorder 45
Records these data continuously,_TwoInjection volume
Used for regulation and treatment water quality data management. In addition,
The turbidity and pH data of the water are above the specified limit.
If an alarm signal is sent to the alarm
And a water quality abnormality alert is issued. In addition, CO_TwoGas bon
The remaining amount of the base 26 and the remaining amount of the inorganic flocculant and the polymer flocculant are
When the value falls below the set value, each sensor (CO _TwoGas cylinder 2
Pressure sensor 25 for 6; PAC tank for inorganic coagulant
23, a level sensor provided in the case of a polymer flocculant
A level sensor provided in the polymer dissolution tank 27)
And an alarm is issued by the medicine residual quantity abnormality alarm 52. Change
In addition, main parts of other equipment such as a raw water transfer pump 20
Is provided with a sensor for detecting an abnormality.
Alarm is issued. The above is the turbid water treatment
It is a description of the process when performing the process.

On the other hand, raw water to be treated may not come out for a while due to circumstances at the construction site. In this case, there is a possibility that the cement-based turbid matter is fixed in the pipe of the raw water flow path 12 up to the separation tank 15, and the pipe line is narrowed or even closed.
Therefore, in the present apparatus, the treated water in the discharge water tank 16 is automatically returned to the raw water flow path 12 by the treated water recirculation flow path 17 when the raw water transfer pump 20 has stopped for a predetermined time.
The treated water is circulated throughout the system to clean the pipeline.

[0021]

In the turbid water treatment apparatus according to the present invention, the floc separation tank has a double structure of an outer tank and an inner tank, and the inner tank is provided at the center bottom of the outer tank. A distance was provided between the edge and the overflow weir. This prevents the flocs floating from the inner tank from being discharged over the overflow weir, thereby preventing the flocs and turbid substances from flowing out.

Further, the flocs flocculated and settled at the bottom of the outer tank around the outer periphery of the inner tank are transferred and circulated to the raw water flow path before entering the separation tank, so that the flocs are used as nuclei to form turbid flocculation and flocs in the separation tank. Will be promoted. Thereby, stable treated water quality can be obtained.

When the raw water is supplied to the inner tank, the raw water is caused to flow in a tangential direction from the side of the lower part of the inner tank, thereby causing the spiral movement of the raw water in the inner tank. The time and the distance are secured, and the cohesion and separation efficiency is improved. Thereby, the aggregation of the turbid matter is performed more efficiently, which contributes to obtaining a stable treated water quality.

While the raw water is not treated, the treated water after the turbid water treatment is returned to the raw water flow path and recirculated. This allows
It is possible to prevent the pipe from being clogged due to the cement material being fixed to the pipe wall, and to prevent a reduction in the processing capacity. Further, extra costs, operations, and time, such as replacing a blocked tube, can be minimized.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a turbid water treatment apparatus according to the present invention.

FIG. 2 is a detailed configuration diagram of a front part of the turbid water treatment device according to the embodiment.

FIG. 3 is a detailed configuration diagram of a middle section of the turbid water treatment apparatus according to the embodiment.

FIG. 4 is a detailed configuration diagram of a rear part of the turbid water treatment device according to the embodiment.

FIG. 5 is an enlarged view of the vicinity of the upper edge of the inner tank of the turbid water treatment device according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Raw water tank 12 ... Raw water flow path 13 ... Line mixer 14 ... Reaction tower 15 ... Separation tank 16 ... Discharge water tank 17 ... Treated water recirculation flow path 20 ... Raw water transfer pump 21 ... Flow control part 22 ... Electromagnetic flow meter 23 ... Polyaluminum chloride (PAC) preparation tank 24 CO ₂ controller 25 Pressure sensor 26 CO ₂ cylinder 27 Polymer dissolving agent dissolving tank 30 Outer tank of separation tank 30 a Upper edge of outer tank (overflow weir) 31 ... Inner tank of separation tank 31a ... Top edge of inner tank 32 ... Stirring plate 33 ... Scraping blade 34 ... Cylindrical injection part 35 ... Sludge reservoir 36 ... Sludge drawing pump 37 ... Slit 38 ... Ring plate 40 ... Sampling tank 41 ... Turbidity sensor 42 ... Treatment water pH sensor 43 ... Turbidity converter 44 ... Discharge pH indicator 45 ... Water quality recorder 46 ... Raw water pH sensor 47 ... Raw water pH indicator 50-52 ... Normal alarm

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Okumura, 17-17 Nishikujo Higashijima-cho, Minami-ku, Kyoto-shi Sanno Co., Ltd. (72) Inventor Katsuhiko Wada 17-3, Nishikujo-Higashijima-cho, Minami-ku, Kyoto Sannouchi Co., Ltd. (72) Inventor Noriyuki Mori 17 shares at 17 Nishikujo Higashijima-cho, Minami-ku, Kyoto-shi Sannouchi Co., Ltd. (72) Yuichi Nishijima 17 shares at 17 Nishikujo-Higashijimacho, Minami-ku, Kyoto-shi Company Sanoh F term (reference) 4D062 BA19 BA28 BB05 CA10 DA04 EA32

Claims (5)

[Claims] 1. A turbid water treatment apparatus for adding a flocculant to raw water, transferring the flocculant to a separation tank, and forming flocs there to remove suspended matter from the raw water, wherein an inner tank is provided inside the separation tank. A turbid water treatment apparatus wherein the upper edge of the tank is lower than the upper edge of the separation tank, and raw water is supplied from a lower side of the inner tank. 2. The turbid water treatment device according to claim 1, wherein a flock outflow slit is provided around a portion slightly below an upper edge of the inner tank. 3. The turbid water treatment apparatus according to claim 1, wherein a stirring plate is provided inside the inner tank, and a flock scraping blade is provided at the bottom of the outer tank, and both are coaxially driven by one motor. . 4. The turbid water treatment apparatus according to claim 1, wherein the floc discharged from the floc reservoir is returned to raw water before entering the separation tank in order to promote the growth of the floc. 5. When the raw water does not flow in the flow path to the separation tank, the treated water from which the suspended matter has been removed in the processing tank is circulated back to the flow path in order to prevent the flow path from being blocked. The turbid water treatment device according to any one of claims 1 to 4, wherein the turbid water treatment device is configured as described above.