JPH09323003A - Clarifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clarifier for effectively making clarifying treatment when using river water, well water or the like as raw water to produce city water and industrial water or when treating various kinds of waste water. SOLUTION: A clarifier 10 is provided with a first clarifying part 14 housed in a first cylindrical tank 18 and a second clarifying part 16 housed in a second cylindrical tank 24 concentrically installed outside the first cylindrical tank 18. The first clarifying part 14 has a contact material accumulated layer 36 in which small piece contact materials having a large void are accumulated. Water to be treated having fine flocs of suspended matter flocculated by an inorganic flocculant is passed through the contact material accumulated layer in a upflow to coagulate the precipitate the flocs while forming a stagnant area in the contact material accumulated layer and to filtrate the water to be treated. The second clarifying part 16 has a filter layer in which a long fiber bundle whose upper end is made a free one is used as a filter medium, and is adjacent to the first clarifying part 14. The water to be treated passed through the first clarifying part 14 is fed in gravity flow and is passed through the filter layer in a downflow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a flocculating apparatus of a coagulating sedimentation type, and more particularly to a turbidity removing apparatus having a turbidity of treated water lower than that of a conventional apparatus.

[0002]

2. Description of the Related Art A coagulating sedimentation clarifier is used to add coagulant to treated water when treating river water, well water, etc. to supply tap water or industrial water, or when treating various effluents. Aggregates and separates minute suspensions contained in water to be treated,
This is a device that reduces the turbidity of treated water. In the conventional flocculation-precipitation type turbidity removing apparatus, as described in, for example, JP-A-6-304411, a flocculant, for example, an aluminum-based inorganic flocculant is added to water to be treated, and a suspension is formed into a floc shape. In many cases, it was constituted by a flocculation-precipitation type turbidification device that flocculates and precipitates the treated water to turbidize the water to be treated.

Now, with reference to FIG. 3, the turbidity removing device 80 described in the above publication will be described. As shown in FIG. 3, the turbidity removing device 80 includes a coagulating sedimentation tank 86 having an upper contact material accumulation zone 82 and an inflow zone 84 below the contact material accumulation zone 82.
In the contact material accumulation zone 82, the contact material accumulation zones 8 are provided with eye-plate-shaped outflow prevention plates 88 and 90 for preventing the contact material from flowing out.
2 are provided in the upper part and the lower part, and in the region between them, many small contact materials in the form of short tubes having a large porosity are accommodated, and under the upper outflow prevention plate 88 by the upward flow of the water to be treated. The contact material integrated layer 89 is formed on the surface. Further, a water collecting trough 92 that collects the treated water overflowing from the upper end of the coagulating sedimentation tank 86 and an outflow pipe 94 connected to the water collecting trough 92 are provided in the contact material collecting zone 82 in order to let the treated water flow out. Is provided above. Inflow zone 8
In No. 4, the inflow pipe 96 penetrates and the water to be treated flows in downward, collides with the current-changing plate 97, and changes into upward flow. An inorganic coagulant injection pipe 98 and an alkaline agent injection pipe 100 are connected to the inflow pipe 96. The bottom of the inflow zone 84 is
It is a sludge storage zone 102, to which a sludge pipe 104 is connected. Further, a backwash air pipe 106 is provided above the inflow zone 84, and the air sent in by the blower 108 is jetted to stir and wash the contact material in the contact material accumulation zone 82.

From the inorganic coagulant injection pipe 98, the coagulant solution is
Further, the water to be treated into which the alkaline solution for pH adjustment is injected from the alkaline agent injection pipe 100 flows into the inflow zone 84,
Of the flocs formed by agglomeration of suspended solids in the water to be treated, relatively large flocs settle and separate there. Then, the water to be treated flows into the contact material accumulation zone 82. There, the remaining fine flocs in the water to be treated contact the contact material and adhere to the surface of the contact material, or are trapped in the gap between the contact material and the contact material, and the water to be treated becomes turbid. The treated water that has been clarified flows out from the top. The flocs adhering to the contact material or trapped between the contact materials gradually grow due to contact with the subsequent fine flocs, etc., and the floc diameter becomes large and the flocculation speed is larger than the rising flow velocity of the treated water. While being formed, the flocs are separated from the contact material by the flow of the water to be treated, settled against the flow of the water to be treated, accumulated in the sludge storage zone 102, and then discharged by the sludge pipe 104.

[0005]

However, in order to directly supply the treated water treated by the conventional turbidity eliminator as tap water or industrial water without additional turbidity treatment, the treated water must be treated. There was a problem that the turbidity was too high. Therefore, various treatment devices have been proposed as additional clarification devices, but the site area is small and the equipment costs
It is the current situation that what can be evaluated as an economical secondary turbidity removal device with low operating costs has not yet been realized.

[0006] Therefore, an object of the present invention is to provide a turbidity eliminator capable of economically sterilizing treated water containing a suspension to supply treated water having a low turbidity.

[0007]

In order to achieve the above-mentioned object, the inventor of the present invention meets the amount of treated water of the flocculation-precipitation clarifier as described in the above publication and the flocculation-precipitation clarifier. The present invention has been completed, paying attention to structurally and hydraulically integrating and combining such a filtration device having a high-speed filtration performance. In order to achieve the above purpose,
The turbidity removing apparatus according to the present invention has a contact material accumulation layer in which small piece contact materials having a large porosity are accumulated, and the treated water containing minute flocs obtained by aggregating a suspension with an aggregating agent is used as a contact material. Water flows upward through the integrated layer to aggregate and separate flocs,
It has a first turbidity part for turbidizing the water to be treated and a filter layer having a long fiber bundle with the upper end as a free end as a filter medium, and flows through the first turbidity part adjacent to the first turbidity part. It is characterized in that it has a second turbidity part for turbidizing the water to be treated by supplying the treated water which has passed through by gravity flow and allowing the filtration layer to flow through in a downward flow to be filtered.

The contact material used in the first turbidity removal section has 60% or more voids that function as water passages when formed as a contact material accumulation layer, and has a surface area of 2 per 1 m ^{3 of} contact material volume.
00m ² or more, a small contact material preferably having a large porosity and surface area, such as having 300 meters ² or more. As the contact material, for example, the outer diameter is 4 to 12 mm and the thickness is 1 to 3 mm.
Then, a short tube-shaped small piece contact material made of plastic having a length of 5 to 20 mm, a small spherical contact material having a hollow portion inside and a large number of holes formed in the surface, or a terraret packing can be used. The material is not particularly limited, and either a floating contact material having a specific gravity of 1 or less or a sinking contact material having a specific gravity of 1 or more may be used, but it is preferable to select a floating material having a specific gravity of less than 1. . The flow velocity in the contact material integrated layer of the water to be treated is 200 m / d to 800 m / d, preferably 300.
By setting m / d to 500 m / d, floc aggregation, growth, separation and sedimentation can be promoted. In the present invention, as the coagulant, for example, inorganic polyaluminum chloride, sulfuric acid band, etc. are used. When an aluminum salt is used as a coagulant, it depends on the turbidity of the raw water, but in order to promote flocculation and growth, it is preferable that the ALT ratio (amount of aluminum injection to the raw water turbidity (mg / l) ratio) is 0.05 to 0.005, and more preferably 0.01 to 0.005.

The long fibers used as the filter material of the second turbidity removing section have, for example, a thickness of about 10 μm to 80 μm and a length of several tens of c.
It is a non-combustible monofilament such as acrylic fiber, polyester fiber, polyamide fiber and the like having a length of m to several m. A long fiber bundle in which a large number (for example, several tens to several hundreds) of such single fibers are bundled with the upper end being a free end, and the lower end of the long fiber bundle is fixed to a fixed plate-like fixing plate and extended upward. Is used as a filter medium. When the water to be treated flows downward in the second turbidity portion having the filtration layer using such a long fiber bundle as a filter medium, residual flocs in the water to be treated and residual suspension that has not reacted with the flocculant Can be efficiently captured.

[0010] In the first turbidity removal portion, flocs are captured on the surface of the contact material due to the blocking effect of the accumulated contact material.
Once the flocs are captured by the contact material, the flocs grow due to the subsequent adhesion growth with the flocs and the cohesive growth of the flocs captured by the contact material. In particular, in the present invention, flocculation is promoted by the effect of the minute stagnation region of the treated water generated on the back side of each contact material, that is, the upper side of each contact material along the upward flow of the treated water. . When the flocs grow to some extent, they are separated by the water flow of the treated water flowing through the contact material accumulation layer, and the flocs having a sedimentation velocity higher than the upward flow velocity of the treated water settle against the flow of the treated water, and the first turbidity Deposit on the bottom of the section.

In the second turbidity removal section, the water to be treated passes through the filtration layer using the long fiber bundle having the upper end as a free end as a filter medium, so that the water to be treated is not captured by the first turbidity removal section. The fine flocs and the suspensions that have flowed into the first turbidity removal part together are trapped between the long fibers very efficiently. Therefore, the content of flocs and suspensions in the treated water exiting the second turbidity removal section is extremely low, and further turbidity control is not required.

According to the present invention, a second turbidity section which is a downward flow type filtration device is provided adjacent to the first turbidity section which is an upward flow type sedimentation filtration apparatus. By partitioning one tank with a partition and accommodating two devices in each, the treated water that flows in from the lower part of the first turbidity section, flows through the first turbidity section in an upward flow, and overflows from the upper part, Immediately under natural flow, it flows into the second turbidity section in a downward flow, so the water collecting trough that collects the water to be treated coming out of the first turbidity section and the second turbidity from the first turbidity section through the second water collection trough. It is possible to omit equipment such as piping for flowing water to be treated to the turbidity removal section. Moreover, since a water supply means such as a pump is not required between the first turbidity removing section and the second turbidity controlling section, the operation is easy. Further, a space for arranging the water collection trough and the pipe is not required, so that the device becomes compact.

The first turbidity section and the second turbidity section may be adjacent to each other, but in practice, the first turbidity section and the second turbidity section are separated from each other by a single partition wall. The turbidity-eliminating device can be accommodated by accommodating it in separate juxtaposed tanks, or by accommodating it in one cylinder tank and the other cylinder tank of a double cylinder tank composed of an outer cylinder tank and an inner cylinder tank, respectively. A more economical structure can be achieved. Further, the side-by-side tanks and the double-barreled tanks are free to have any shape such as a quadrangle, a circle, and an ellipse in cross section. Further, in the case of the double cylindrical tank, it may be concentric or non-concentric, and the first turbidity portion and the second turbidity portion may be housed in the outer tubular tank and the inner tubular tank, respectively, and vice versa. . With the above configuration, the total tank wall area of the entire device can be reduced and the tank wall thickness can be reduced compared to the case where each decontamination part is housed in a separate tank, thus reducing equipment costs. can do.

According to a preferred embodiment of the present invention, a mixing tank for adding flocculant to the water to be treated to form flocs is adjacent to the first turbidizing section, and the water to be treated in the mixing tank is gravity-fed. The water to be treated is first fed to the admixture tank by a single water pump by flowing it into the first opacifier, and thereafter the treated water is further transferred from the admixture tank to the first opacifier. Water can flow from the first turbidity removal section to the second turbidity removal section due to a water level difference. Therefore, driving is easy.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail based on embodiments with reference to the accompanying drawings. Example This example is an example in which the present invention is applied as a turbidity removing device when purifying river water into tap water. FIG. 1 is a schematic diagram showing the structure of the turbidity removing apparatus of this embodiment. As shown in FIG. 1, the turbidity removing apparatus 10 according to the present embodiment has an integrated structure including a mixing tank 12, a first turbidity removing unit 14, and a second turbidity removing unit 16. The 1st turbidity part 14 is comprised in the 1st cylindrical tank 18, and the area | region 20 divided into the upper part of the 1st cylindrical tank 18 in order to filter the to-be-processed water, making flocs in the to-be-processed water flocculate and settle. (Hereinafter, simply referred to as area 20)
It is composed of an inflow region 22 defined below the region 20 for inflowing the water to be treated, and a sludge storage region 23 at the bottom of the inflow region 22. The second turbidity-eliminating part 16 is provided in the annular space between the first cylindrical tub 18 and the second cylindrical tub 24 concentrically formed on the outer periphery thereof, and the first turbidifying part 1 is provided.
It comprises a filtration region 26 for filtering the water to be treated which has passed through 4 and a filtered water chamber 28 below the filtration region 26.

The area 20 of the first turbidity removing section 14 is divided into upper and lower parts by an upper eye plate 30 and a lower eye plate 32 which are horizontally formed by perforated plates such as a grid plate and a punching plate, and have a height of 1 to 1. It is an area of 2 m. In that area, a tubular small-diameter plastic contact material 34 having a hollow portion inside, for example, a length of 20 mm and an outer diameter of 12 m
A large number of macaroni-shaped floating contact materials 34 (see FIG. 2) having an m and an inner diameter of 8 mm and a specific gravity of less than 1.0 are accommodated. The contact material 34 having such a specific gravity floats from the beginning of the passage of the water to be treated and is shielded by the upper eye plate 30, so that the contact material accumulation layer 3 is formed.
6 is formed. The contact material accumulation layer 36 in which the contact materials are accumulated is
Usually, it occupies the upper 50 to 70% of the entire area 20. First
A saw-tooth-shaped overflow weir 38 is provided on the upper edge of the cylindrical tank 18 so as to extend from the upper edge of the first cylindrical tank 18 to the second clouding section 1.
The water to be treated flows down with a uniform distribution in No. 6.

The inflow region 22 of the first turbidity removing unit 14 is constituted by the lower portion of the first cylindrical tank below the lower eye plate 32, and the bottom portion 40 of the first cylindrical tank 18 facilitates accumulation of flocs and sludge removal. As such, it has a truncated cone shape and constitutes the sludge storage area 23. At the center of the first cylindrical tank of the inflow region 22, a disc-shaped current changing plate 42 is provided. The inflow pipe 44 through which the water to be treated flows from the mixing tank 12 penetrates through the tank walls of the second cylindrical tank 24 and the first cylindrical tank 18 to reach the upper side of the current changing plate 42, and faces downward toward the current changing plate 42. Have an exit. Below the current change plate 42, a sludge discharge pipe 46 for discharging sludge from the flocs accumulated in the sludge storage area 23 is provided. Also, the lower eye plate 32
Immediately underneath, a plurality of nozzles for ejecting air upward are provided, and an air ejection pipe 48 for ejecting air to wash the contact material accumulated layer 36 is provided.

The filtering region 26 and the filtered water chamber 28 of the second turbidity removing unit 16 are provided in an annular space between the first cylindrical tank 18 and the second cylindrical tank 24, and have an annular plate-like horizontal mesh. The plates 50 separate from each other. In the filtration region 26, a large number of long fiber bundles obtained by bundling a large number of long fibers are broom-shaped in a broom shape extending upward with the upper end as a free end, and the filter medium 5
2 is planted to form a filtration layer. A large number of nozzles for ejecting air upward are provided, and an air ejection pipe 54 for ejecting air to wash the filter medium 52 is provided immediately below the eye plate 50 in a ring shape along the annular eye plate 50. is there. Further, a filtered water pipe 56 for sending the filtered water to the treated water tank 55,
A wash water pipe 60 for sending wash water from the treated water tank 55 through the filtered water chamber 28 to the filtration region 26 by the wash water pump 58,
It is connected to the filtered water chamber 28. Furthermore, the second cylindrical tank 24
A wash water discharge pipe 62 for draining wash water from the filtration region 26 is connected to the upper part of the. Incidentally, 57 is the treated water tank 5
5 is a water pipe for sending treated water to the outside.

The mixing tank 12 is a tank provided with an agitator 64 and adjacent to the upper part of the second cylindrical tank 24. The inlet opening of the inflow pipe 44 is located near the liquid surface, and the treated water is treated. Flows in through the opening and flows into the inflow region 22 of the first turbidity removal unit 14 through the inflow pipe 44. In order to inject the solution in which the inorganic coagulant is dissolved into the water to be treated, an inorganic coagulant solution pipe 70 with an injection pump 68 interposed is connected to a water conduit 66 for introducing the water to be treated into the mixing tank 12. . In addition, the turbidity removing device 10 is provided with a blower 72 that sends air to the air ejection pipes 48 and 54.

The operation method of the turbidity removing apparatus 10 of this embodiment will be described below. The inorganic coagulant solution is injected into the water to be treated guided by the water conduit 66 through the inorganic coagulant solution pipe 70 and placed in the mixing tank 12, where it is rapidly stirred by the stirrer 64, and then the inorganic coagulant and the inflow pipe 44 are used. First clouding part 14
Is introduced into the inflow region 22 of. The water to be treated introduced into the inflow region 22 first collides with the current changing plate 44 to promote the formation of flocs. Among the formed flocs, those having a sedimentation velocity higher than the velocity of the water to be treated flowing upwardly across the inflow region 22 settle in the inflow region 22 and are deposited on the bottom portion 40. On the other hand, the other relatively small-diameter flocs rise, pass through the lower eye plate 32, and flow into the contact material accumulation layer 36.

In the contact material accumulation layer 36, most of the flocs come into contact with the contact material and are trapped in the outer surface and hollow surface of the contact material, and also in the gap formed between the contact materials. Most of the flocs captured by the contact material combine with the flocs newly flowing into the contact material accumulation layer 36 later and grow into particles having a higher sedimentation velocity. In particular, in this embodiment, the flocculation is promoted by the effect of the minute stagnation region of the treated water generated on the back side of each contact material, that is, the upper side of each contact material along the upward flow of the treated water. It When the floc diameter grows and becomes large enough that the sedimentation velocity of the flocs exceeds the flow velocity of the treated water flowing upward in the contact material accumulation layer 36 at that time, the flocs separate from the contact material and descend. After passing through the lower eye plate 32, the sludge is accumulated on the bottom portion 40 of the sludge storage zone 23 to become concentrated sludge. on the other hand,
The minute flocs that have not been captured by the contact material and the suspension that has not reacted with the inorganic coagulant are entrained in the water to be treated and overflow from the overflow weir 38 to the second turbidity removal section 16. The water to be treated that has flowed into the second turbidity removal section 16 along with the flocs and the suspended matter flows through the filtration layer composed of the long fiber bundle filter media 52 while flowing in a downward flow. In the meantime, the flocs and suspensions are filtered by the filter medium 5
The treated water, which is captured by 2 and becomes clear water, passes through the eye plate 50 and enters the filtered water chamber 28, and further passes through the filtered water pipe 56,
Enter the treated water tank 55.

In this embodiment, the water to be treated enters the first turbidity section 14 from the mixing tank 12 by gravity flow.
After passing through the contact material accumulating layer 36, the second turbidity removing section 1 passes from the overflow weir 38.
6, the filter medium 52 is passed through, and the treated water tank 55 is entered. The head loss required for the series of natural flow is the mixing tank 1
It is equal to the height difference between the water surface of the treated water of No. 2 and the water surface of the treated water tank 55. By the way, the loss head when flowing through the first turbidity portion 14 and the loss resistance when flowing from the first turbidity portion 14 into the second turbidity portion 16 are the treated water flowing upward through the first turbidity portion 14. When the water flow rate is 200 to 800 m / d, it is so small that it can be ignored. And the loss at the time of passing through the second turbidity removal section 16 are approximately equivalent. Since they are relatively small and therefore the mixing tank 12 can be arranged at a relatively low position, the discharge pressure of the pump for guiding the water to be treated to the mixing tank 12 can be suppressed to a low level.

When flock is abnormally accumulated on the contact material in the contact material accumulation layer 36, the pressure loss increases, so the introduction of the water to be treated is temporarily stopped and the air is ejected from the air ejection pipe 48. The contact material integrated layer 36 is cleaned with air to clean the contact material. Further, with the lapse of time, flocs and suspensions are accumulated in the filter medium 52 of the second turbidity removal unit 16, the filter performance of the filter medium is deteriorated, and the pressure loss is increased. Therefore, the cleaning operation of the filter medium 52 is regularly performed. First, the introduction of the water to be treated is stopped, then air is jetted from the air jet pipe 54 to agitate the filter medium 52, and the trapped flocs and the like are separated from the filter medium 52, and at the same time, the washing water pump 58 is started. Treated water as washing water from the treated water tank 55 to the washing water pipe 6
Water is sent to the filtration region 26 via 0, and the separated flocs and the like are caused to accompany the cleaning water and discharged from the cleaning water discharge pipe 62. It is preferable that the cleaning operation of the first turbidity removing unit 14 and the cleaning operation of the second turbidity removing unit 16 are performed simultaneously.

[0024]

According to the present invention, the first turbidity portion and the second turbidity portion are structurally and hydraulically integrated so that the water to be treated having a high turbidity is turbid. We have realized a sterilization device that can economically and easily operate turbidity treatment of low treated water. In particular, by making the first turbidity section and the second turbidity control section adjacent to each other and having an integral structure, the tank wall area of the tank for housing the first turbidity control section and the second turbidity control section can be reduced, 1 turbidity section and 2nd
No need for pipes, pumps, etc. to connect to the turbidity removal unit.
This will save the site area, equipment costs, and operating costs. In addition, since the head loss is small between the first turbidity section and the second turbidity control section, the height difference between the first turbidity control section and the second turbidity control section can be reduced, and as a result, the turbidity control apparatus as a whole can be provided. However, the structure is not so tall.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a contact member.

FIG. 3 is a schematic view showing a configuration of a conventional turbidity removing device.

[Explanation of symbols]

10 Examples of the turbidity eliminator according to the present invention 12 Mixing tank 14 First turbidity section 16 Second turbidity section 18 First cylindrical tank 20 Area for filtering the water to be treated while flocculating and precipitating flocs in the water to be treated 22 Inflow Area 23 Sludge Storage Area 24 Second Cylindrical Tank 26 Filtration Area 28 Filtered Water Chamber 30 Upper Eye Plate 32 Lower Eye Plate 34 Contact Material 36 Contact Material Accumulation Layer 38 Overflow Weir 40 Bottom 42 Current Change Plate 44 Inflow Pipe 46 Discharge Mud pipe 48 Air jet pipe 50 Eye plate 52 Filter media 54 Air jet pipe 55 Treated water tank 56 Filtered water pipe 57 Water pipe 58 Wash water pump 60 Wash water pipe 62 Wash water discharge pipe 64 Stirrer 66 Water guide pipe 68 Injection pump 70 Inorganic coagulant solution pipe 72 Blower

Claims (3)

[Claims] 1. A contact material accumulating layer in which a small piece contact material having a large porosity is accumulated, and treated water containing minute flocs obtained by aggregating a suspension with an aggregating agent is applied to the contact material accumulating layer. It has a first turbidity section that flows countercurrently to flocculate and separate flocs to turbidize the water to be treated, and a filtration layer that uses a long fiber bundle with the free end at the top as a filter medium. Adjacent to the turbid part, the water to be treated which has passed through the first turbidity part is supplied by gravity flow, and the filtration layer is passed in a downward flow to be filtered to turbidize the water to be treated. A turbidity removing device having a turbid portion. 2. A double cylinder tank in which the first turbidity removing section and the second turbidity controlling section are respectively accommodated in juxtaposed tanks having one tank partitioned by a partition wall, or an outer cylinder tank and an inner cylinder tank. The turbidity removing apparatus according to claim 1, wherein the turbidity removing apparatus is housed in one of the cylindrical tanks and the other cylindrical tank, respectively. 3. A mixing tank for adding flocculant to treated water to form flocs is adjacent to the first turbidity section, and the treated water in the mixing vessel is gravitationally flowed to the first turbidity section. The turbidity removing apparatus according to claim 1 or 2, wherein the turbidity removing apparatus is configured to flow into the turbidity measuring apparatus.