Flocculant forming apparatus for water purification and its operating method

Abstract

To provide a floc formation device which can perform floc formation reliably and with good efficiency, and can achieve down-sizing of equipment, and an operation method of the same.SOLUTION: A floc formation device 1 for water purification comprises: an inflow chamber 20 in which water to be treated from pretreatment equipment flows; an agitator 40 for agitating water to be treated flown in the inflow chamber 20; a baffle chamber 60 that flows down water to be treated, which has been agitated, while baffling the same by a baffle plate 61; and an outflow chamber 80 which flows out water to be treated, which has flown in from the baffle chamber 60, to subsequent stage equipment. The inflow chamber 20 and the outflow chamber 80 are located close to each other. The baffle chamber 60 has a returning structure for returning water to be treated which has flown in from the inflow chamber 60, and flows down the same to the outflow chamber 80. By providing a circulation opening 31 which connects the inflow chamber 20 and the outflow chamber 80, a circulation flow passage, in which a part of water to be treated circulates through the inflow chamber 20, the baffle chamber 60, and the outflow chamber 80, is formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a floc formation device for water purification suitable for use in floc formation treatment in the coagulation sedimentation treatment step of water purification treatment and an operation method thereof.

Background Art

[0002] Conventionally, in water purification (purified water and service water) treatment, in order to obtain clean water that satisfies tap water quality from raw water for tap water such as river water and lake water, coagulation sedimentation treatment, filtration treatment, and disinfection treatment are performed. Coagulation sedimentation treatment is an operation in which a flocculant chemical is used to aggregate suspended substances in water and perform treatment so that solid-liquid separation can be performed in a sedimentation tank. Coagulation sedimentation treatment equipment includes a mixing tank that quickly disperses the injected flocculant into the raw water to perform charge neutralization and reduce the repulsive force (repulsion) between suspended substances, and a floc formation device that coarsens the suspended substances charge-neutralized in the mixing tank so that solid-liquid separation can be performed in the subsequent sedimentation tank. The stirring method in the floc formation device is roughly classified into two types: mechanical stirring and circulation stirring.

[0003] The above mechanical stirring is performed using a dedicated stirrer. Although this mechanical stirring has good followability to flow rate fluctuations, it is necessary to regularly perform repairs and replacements of the stirrer, and furthermore, driving energy for driving the stirrer is required.

[0004] On the other hand, the above circulation stirring is a method of using the water head (position energy) of water for stirring. For this reason, circulation stirring does not require mechanical failures or component replacements including the drive unit, and can effectively utilize position energy (natural energy), but it is difficult to follow the water volume fluctuations in a water purification plant where it is inevitable to increase or decrease the treated water volume. That is, in the case of circulation stirring, when the water volume decreases, the stirring force also decreases, and the contact opportunity between flocs decreases, so there is a risk that the flocs cannot grow well. However, from the perspective of effective utilization of natural energy in recent years, it has attracted attention as a device with low LCC (life cycle cost).

[0005] Patent Document 1 discloses a method and apparatus for treating sewage mixed with rainwater, in which an inorganic coagulant and an organic polymer coagulant are added in two stages inside a bypass-flow mixing tank, and coagulation is performed using a stirrer for coagulation in some cases. Patent Document 2 discloses a solid-liquid separation system in which a coagulant or coagulation aid is injected into a mixing tank and dispersed by a stirrer, and then flocs are generated in a floc formation tank having a bypass-flow channel. Patent Document 3 discloses a method and apparatus for treating sewage mixed with rainwater, in which an inorganic coagulant and an organic polymer coagulant are added in two stages inside a bypass-flow channel to perform coagulation. Non-Patent Document 1 discloses basic design guidelines for a floc formation device. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2004-344778 [Patent Document 2] Japanese Patent Publication No. 2013-49057 [Patent Document 3] Japanese Patent Publication No. 2005-177602 [Non-Patent Document 1] "Water Supply Facility Design Guidelines 2012" (Japan Water Works Association), p. 186, "5.4.3 Flocculation Ponds" [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Patent documents 1, 2, and 3, and non-patent document 1 all disclose bypass-flow agitation. However, as mentioned above, in water treatment plants where fluctuations in the amount of treated water are unavoidable, there are difficulties in following these fluctuations in water volume. When the water volume decreases, the agitation force also decreases, which could prevent flocs from growing properly. Furthermore, if the bypass channel is lengthened to improve floc formation, it may become difficult to achieve a compact design.

[0008] The present invention has been made in view of the above-mentioned points, and its purpose is to provide a water purification floc formation apparatus and a method for operating the same that can reliably and efficiently form flocs regardless of increases or decreases in the amount of treated water, and that can also be made more compact. [Means for solving the problem]

[0009] The present invention relates to a floc formation apparatus for water purification used in the floc formation process of the coagulation and sedimentation treatment process, comprising an inlet chamber into which water to be treated flows in from a chemical mixing tank into which chemicals are mixed, and the water to be treated that flows into the inlet chamber To provide a G value that maintains good floc formation. The system comprises a stirrer for agitation, a bypass chamber for allowing the water to be treated, which flows in from the inlet chamber, to flow downwards via a bypass plate, and an outlet chamber for allowing the water to be treated, which flows in from the bypass chamber, to be discharged to downstream equipment. The inlet chamber and the outlet chamber are arranged in close proximity, and the bypass chamber has a reversal structure in which the water to be treated, which flows in from the inlet chamber, reverses direction and flows downwards into the outlet chamber. Further down the line, there are facilities such as sedimentation tanks. According to the present invention, by using a folded structure for the bypass chamber and arranging the inlet and outlet chambers in close proximity, the equipment can be made smaller and more compact, while at the same time the bypass channel can be made longer, which promotes good floc growth. Furthermore, as mentioned above, fluctuations in the volume of treated water are unavoidable in water treatment plants. However, when the volume of treated water decreases, the water to be treated that flows into the inflow chamber is stirred by a stirrer, which gives it a G value (a value representing the stirring intensity), thereby improving the floc formation capacity in the bypass chamber.

[0010] Furthermore, the present invention, In a floc formation apparatus for water purification used in the floc formation process of the coagulation and sedimentation treatment process, the apparatus comprises an inlet chamber into which water to be treated flows from a pretreatment facility, a stirrer for stirring the water to be treated that flows into the inlet chamber, a bypass chamber for which the water to be treated that flows in from the inlet chamber flows downward while bypassing it with a bypass plate, and an outlet chamber for which the water to be treated that flows in from the bypass chamber flows out to a downstream facility, wherein the inlet chamber and the outlet chamber are arranged in close proximity, and the bypass chamber has a reversal structure in which the water to be treated that flows in from the inlet chamber folds back and flows down to the outlet chamber, The system is characterized by the provision of a circulation opening connecting the inlet chamber and the outlet chamber, thereby forming a circulation channel through which a portion of the treated water circulates through the inlet chamber, bypass chamber, and outlet chamber. According to the present invention, the floc formation effect can be further improved by contact coagulation, which brings into contact the water to be treated flowing in from the pretreatment equipment with the floc-formed water to be treated circulating from the outlet chamber.

[0011] Furthermore, in addition to the above features, the present invention is characterized in that the circulation opening is equipped with an opening adjustment means for adjusting the circulation flow rate. According to the present invention, the circulation flow rate of the treated water circulated from the outflow chamber to the inflow chamber can be easily adjusted to a flow rate suitable for floc formation.

[0012] Furthermore, in addition to the above features, the present invention is characterized by the installation of a backflow prevention gate in the circulation opening to prevent short-circuit flow from the inlet chamber to the outlet chamber. According to the present invention, it is possible to reliably prevent the flow of a short-circuit flow in which the water to be treated flows from the pretreatment equipment into the inlet chamber and then flows directly into the outlet chamber.

[0013] In addition to the above features, the present invention is further characterized in that the circulation opening is equipped with both an opening adjustment means for adjusting the circulation flow rate and a backflow prevention gate for preventing short-circuit flow from the inlet chamber to the outlet chamber. According to the present invention, the circulation flow rate of the treated water circulated from the outlet chamber to the inlet chamber can be easily adjusted to a flow rate suitable for floc formation, while simultaneously reliably preventing short-circuit flow from the inlet chamber to the outlet chamber.

[0014] Furthermore, the present invention, In a floc formation apparatus for water purification used in the floc formation process of the coagulation and sedimentation treatment process, the apparatus comprises an inlet chamber into which water to be treated flows from a pretreatment facility, a stirrer for stirring the water to be treated that flows into the inlet chamber, a bypass chamber for the water to be treated that flows down while bypassing the water to be treated that flows in from the inlet chamber by a bypass plate, and an outlet chamber for the water to be treated that flows in from the bypass chamber and is discharged to a downstream facility, wherein the inlet chamber and the outlet chamber are arranged in close proximity, and the bypass chamber has a reversal structure in which the water to be treated that flows in from the inlet chamber folds back and flows down to the outlet chamber, and further, The device is characterized by comprising an inflow state measuring unit that measures the state of the amount of water to be treated by the water purification floc formation device, and a control unit that controls the operating state of the agitator according to the state of the amount of water to be treated measured by the inflow state measuring unit. According to the present invention, the operating state of the agitator is controlled according to the amount of water to be treated, so that the G value applied to the water to be treated can be adjusted to a value suitable for floc formation.

[0015] In addition to the above features, the present invention is also characterized in that the control unit operates the agitator or increases its rotational speed when the amount of water to be treated decreases. According to the present invention, even when the amount of the water to be treated decreases, by increasing the G value applied to the water to be treated, a state suitable for floc formation can be achieved. Further, by adjusting the rotational speed of the stirrer, the circulation flow rate of the water to be treated circulated from the outflow chamber to the inflow chamber can also be adjusted. Therefore, the circulation flow rate can be adjusted by either one or both of the adjustment of the rotational speed of the stirrer and the adjustment of the opening degree by the opening degree adjustment means of the circulation opening.

[0016] In addition to the above features, the present invention is characterized by including a control unit that controls the amount of the water to be treated circulated from the outflow chamber to the inflow chamber by the pumping action of the stirrer by increasing or decreasing the rotational speed of the stirrer. According to the present invention, by controlling the rotational speed of the stirrer, the amount of the water to be treated circulated from the outflow chamber to the inflow chamber is controlled, and thereby the floc formation action by contact aggregation of the water to be treated flowing in from the pretreatment facility and the water to be treated circulated from the outflow chamber can be effectively improved. The amount of the water to be treated circulated from the outflow chamber to the inflow chamber can be adjusted by either one or both of the control of the rotational speed of this stirrer and the opening degree control by the opening degree adjustment means of the circulation opening.

[0017] Also Ta, In an operation method of a floc formation device for purified water used for floc formation treatment in the coagulation sedimentation treatment step of purified water treatment, the floc formation device for purified water includes an inflow chamber into which the water to be treated from the pretreatment facility flows in, a stirrer that stirs the water to be treated flowing into the inflow chamber, a circulation chamber that allows the water to be treated flowing into the inflow chamber to flow down while being circulated by a circulation plate, and an outflow chamber that allows the water to be treated flowing into the circulation chamber to flow out to a subsequent facility. Changing the operating state of the stirrer according to the amount of the water to be treated flowing into the inflow chamber also preferable . covered Since the operating state of the stirrer is changed according to the amount of the treated water, the G value applied to the water to be treated can be adjusted to a value suitable for floc formation.

[0018] Also Ta,In addition to the above features, when the amount of the water to be treated decreases, the stirrer is operated or the rotation speed is increased. also preferable . covered By operating the stirrer or increasing the rotation speed when the amount of the treated water decreases, the G value applied to the water to be treated can be adjusted to a value suitable for floc formation.

[0019] In Ta, In addition to the above features, a circulation flow path connecting the inflow chamber and the outflow chamber is formed in the floc formation device for purified water, and the amount of the water to be treated circulated from the outflow chamber to the inflow chamber by the pumping action of the stirrer is adjusted by increasing or decreasing the rotation speed of the stirrer. also preferable . Scratch In addition to the function of adjusting the G value applied to the water to be treated, the stirrer can be provided with a function of adjusting the amount of the water to be treated circulated from the outflow chamber to the inflow chamber. That is, the stirrer can have both the effect of applying the G value to the water to be treated when the amount of water decreases and the effect of improving the floc formation action by contact aggregation of the water to be treated flowing in from the pretreatment equipment and the water to be treated circulated from the outflow chamber.

[0020] In Ta, In the floc formation device for purified water used for floc formation treatment in the coagulation sedimentation treatment step of purified water treatment, an inflow chamber into which the water to be treated flows in from the pretreatment equipment, a recirculation chamber in which the water to be treated flowing in from the inflow chamber flows down while being recirculated by a recirculation plate, and an outflow chamber in which the water to be treated flowing in from the recirculation chamber flows out to the subsequent equipment are provided. The inflow chamber and the outflow chamber are arranged close to each other, and the recirculation chamber has a return structure in which the water to be treated flowing in from the inflow chamber turns back and flows down to the outflow chamber, thereby unitizing the inflow chamber, the outflow chamber, and the recirculation chamber. do This also preferable . outfit Since the entire device is unitized, it can be easily stored and installed, for example, in an existing floc formation tank.

Effects of the Invention

[0021] According to the present invention, floc formation can be reliably and efficiently carried out regardless of increases or decreases in the amount of treated water, and the equipment can also be made more compact. [Brief explanation of the drawing]

[0022] [Figure 1] This is a schematic plan view of the water purification floc formation apparatus 1. [Figure 2] This is a schematic cross-sectional view of AA in Figure 1. [Figure 3] This is a cross-sectional view of BB as seen through the arrow in Figure 1. [Figure 4] This is a control block diagram showing the control means for the floc forming apparatus 1. [Figure 5] This is a schematic diagram of an enlarged vertical cross-section of the circulation opening 31. [Figure 6] This is an explanatory diagram of the replacement method when replacing the conventional floc forming apparatus 200 with the floc forming apparatus 1. [Figure 7] This is an explanatory diagram of the replacement method when replacing the conventional floc forming apparatus 200 with the floc forming apparatus 1. [Figure 8] This is an explanatory diagram of the replacement method when replacing the conventional floc forming apparatus 200 with the floc forming apparatus 1. [Figure 9] This is a schematic plan view of the water purification floc formation apparatus 1-2. [Figure 10] Figure 9 is a schematic cross-sectional view of CC. [Figure 11] This figure shows an example of a stirrer 40, with Figure 11(a) being a perspective view and Figure 11(b) being a cross-sectional view of Figure 11(a) taken along the DD arrow. [Modes for carrying out the invention]

[0023] As described above, the water purification floc formation device is part of the coagulation and sedimentation treatment equipment (coagulation and sedimentation treatment process). It is connected downstream of the chemical mixing tank, where a coagulant is injected and dispersed into the raw water to neutralize its charge, and is a device that coagulates the suspended solids that have been neutralized in the chemical mixing tank. A sedimentation tank is installed downstream of the floc formation device to settle the coarsened flocs.

[0024] Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a schematic plan view of a water purification floc formation apparatus 1 according to one embodiment of the present invention, Figure 2 is a schematic cross-sectional view AA of Figure 1, and Figure 3 is a cross-sectional view taken along arrow BB of Figure 1. As shown in these figures, the water purification floc formation apparatus (hereinafter sometimes simply referred to as "floc formation apparatus") 1 comprises a flow straightening plate 10 through which water to be treated from a chemical mixing tank (rapid mixing tank), which is a pretreatment facility, passes; an inlet chamber 20 into which water to be treated that has passed through the flow straightening plate 10 is introduced; a stirrer 40 installed in the inlet chamber 20 to agitate the water to be treated that flows into the inlet chamber 20 as needed; a bypass chamber 60 into which water to be treated is introduced from the outlet 27 of the inlet chamber 20; an outlet chamber 80 installed adjacent to the inlet chamber 20 into which water to be treated that has flowed out from the bypass chamber 60 is introduced from the inlet 81; and a flow straightening plate 100 that straightens the water to be treated that has flowed out from the outlet 83 of the outlet chamber 80 and flows out to a sedimentation tank, which is a downstream facility.

[0025] As shown in Figure 3, the flow straightening plate 10 straightens the water to be treated flowing in from the chemical mixing tank, which is a pretreatment facility, by providing numerous through holes 11. Although the figure shows through holes 11 for straightening, flow straightening plates of various other structures may also be used.

[0026] As shown in Figure 1, the inlet chamber 20, the bypass chamber 60, and the outlet chamber 80 are unitized into a rectangular box shape and are configured to be installed between a pair of rectifier plates 10, 100.

[0027] As shown in Figures 2 and 3, the inlet chamber 20 is divided vertically by a partition plate 21, an inlet 23 is provided on the side wall 21 on the side of the rectifier plate 10 above the partition plate 21 (20A), an outlet 27 is provided on the upper part of the side wall 25 on the side of the bypass chamber 60 above the partition plate 21 (20A), and a flow opening 29 is provided that penetrates vertically through the partition plate 21 approximately in the center.

[0028] In the lower part of the side wall 25 on the bypass chamber 60 side, below the partition plate 21 of the inlet chamber 20, on the side 20B (the surface facing the outlet chamber 80, the partition wall), a roughly rectangular circulation opening 31 is formed that penetrates through the inlet chamber 20 and the outlet chamber 80, connecting them.

[0029] Figure 5 is a schematic diagram of an enlarged vertical cross-section of the circulation opening 31. As shown in the figure, the circulation opening 31 has a backflow prevention gate 33 on the inlet chamber 20 side and an opening adjustment door 35 on the outlet chamber 80 side.

[0030] The backflow prevention gate 33 is sized and shaped to close the circulation opening 31, and its upper edge is rotatably attached to the side wall 25 by a hinge mechanism 331, so that the backflow prevention gate 33 can rotate only in the direction toward the inlet chamber 20 (direction of arrow E in Figure 5). In other words, the backflow prevention gate 33 operates in such a way that it is possible for the treated water to move from the outlet chamber 80 to the inlet chamber 20, but movement in the reverse direction is prevented.

[0031] The opening degree adjustment door 35 is sized and shaped to close the circulation opening 31, and has a rod-shaped drive member 37 attached to its upper edge. An opening / closing mechanism drive unit 39 is attached to the upper part of the drive member 37 to drive it vertically. By driving the opening / closing mechanism drive unit 39, the opening degree adjustment door 35 is moved up and down, thereby adjusting the opening degree of the circulation opening 31. The entire opening degree adjustment door 35, drive member 37, and opening / closing mechanism drive unit 39 are referred to as the opening degree adjustment mechanism.

[0032] Returning to Figures 1 to 3, the agitator 40 is constructed by attaching a rotary drive shaft 41 to its upper surface, and further attaching an agitator drive unit 43 to the upper part of the rotary drive shaft 41 to rotate the rotary drive shaft 41. In Figure 3, the agitator 40 is shown with blades arranged radially from the center, but in reality, taking into account the water pumping capacity, it is more desirable to use an agitator 40 consisting of an impeller with an involute blade shape, as used in centrifugal pumps, as shown in Figures 11(a) and (b). When the agitator drive unit 43 is driven, the agitator 40 rotates. This agitator 40 has two functions: one is to apply pressure to the water to be treated by centrifugal force, thereby giving the water to be treated flowing in from the inlet 23 of the inlet chamber 20 a G value and increasing the stirring force on the water to be treated flowing out into the bypass chamber 60, thereby increasing the opportunity for contact between flocs (stirring function); and the other is to draw the water to be treated from the circulation opening 31, draw it up through the flow port 29, and discharge it in a plane direction perpendicular to the rotating drive shaft 41 (circulation function). Of course, agitators of various other structures may also be used. In terms of the circulation function, the agitator 40 with stirring blades can also be called a circulator with circulation blades.

[0033] The bypass chamber 60 is constructed by arranging a number of bypass plates 61 to bypass the treated water flowing from upstream to downstream. Each bypass plate 61 is positioned so that its surface intersects the flow of the treated water, and is provided with treated water insertion sections 63, consisting of desired notches or through holes, on its upper, lower, and left and right sides. By varying the positions of the treated water insertion sections 63 of adjacent bypass plates 61, agitation occurs as the treated water flows downstream, effectively promoting floc formation. It goes without saying that various modifications are possible to the installation positions of the bypass plates 61 and the shape and installation positions of the treated water insertion sections 63.

[0034] In this embodiment, the bypass chamber 60 flows from the inlet chamber 20, flows away from the inlet chamber 20, then turns back at the turnaround section 65, and flows down toward the outlet chamber 80 adjacent to the inlet chamber 20. In other words, the bypass structure has a turnaround structure where the flow path is partitioned by a partition wall 67 and turned back.

[0035] The outflow chamber 80 is a chamber formed at the downstream end of the last bypass plate 61. The outflow chamber 80 and the inflow chamber 20 are separated by a side wall (partition wall) 25. The outflow chamber 80 has an inlet 81 for receiving the water to be treated from the bypass chamber 60, an outlet 83 for receiving the water towards the rectifier plate 100, and a circulation opening 31 for circulating a portion of the water to be treated back into the inflow chamber 20. The outlet 83 may also be provided with a variable outlet wall height structure that allows the height of its lower edge to move up and down, thereby enabling control and maintenance of the water level inside the outflow chamber 80.

[0036] The rectifier plate 100 rectifies the treated water flowing out from the outlet 83 of the outflow chamber 80 and directs it toward the sedimentation tank, which is a downstream facility. It is provided with numerous through holes 111 to rectify the treated water flowing in from the outflow chamber 80.

[0037] Figure 4 is a control block diagram showing the control means of the floc forming apparatus 1. As shown in the figure, the control means of the floc forming apparatus 1 comprises a control unit 120, an inflow state measuring unit 121, an opening degree detection unit 123, the agitator drive unit 43, and the opening / closing means drive unit 39.

[0038] The inflow state measuring unit 121 is a device (in this example, a flow meter) that measures the inflow state (in this example, the inflow rate) of the water to be treated flowing from the chemical mixing tank, which is a pretreatment facility, into the floc formation device 1. The inflow state measuring unit 121 is installed, for example, at a predetermined position between the chemical mixing tank and the floc formation device 1, and measures the flow rate of the water to be treated, outputting the measured value to the control unit 120. Alternatively, instead of measuring the inflow rate, the inflow state measuring unit 121 may measure the excess or deficiency of the inflow rate by measuring the water level inside the bypass chamber 60 or at other locations, or it may be configured to measure the amount of water flowing out from the outlet 83. Furthermore, the quality of the inflow state may be determined by detecting the growth state of the flocs growing inside the bypass chamber 60. In short, it is sufficient if the device can detect whether the inflow state of the water to be treated into the bypass chamber 60 is excessive or insufficient.

[0039] The opening degree detection unit 123 detects the opening degree of the circulation opening 31. Although not shown in the figure, it detects the opening degree by, for example, measuring the vertical position of the drive member 37 which is located above the water surface, and outputs the measured value to the control unit 120. Of course, other types of opening degree detection units are also acceptable.

[0040] The control unit 120 uses the inflow state of the water to be treated, input from the inflow state measuring unit 121, and the opening degree of the circulation opening 31, input from the opening degree detection unit 123, to output control signals to the agitator drive unit 43 and the opening / closing means drive unit 39, thereby adjusting the rotation speed of the agitator 40 and the opening degree of the circulation opening 31.

[0041] Next, an example of how to operate the floc forming apparatus 1 will be described. In a chemical mixing tank, which is a pretreatment facility not shown, a coagulant is added, and if necessary, the water to be treated, in which the coagulant is dispersed and the suspended solids are neutralized by stirring with a stirrer, is straightened through each through-hole 11 of the straightening plate 10.

[0042] The water to be treated, having passed through the rectifier plate 10, flows into the inlet chamber 20 through the inlet 23. The water to be treated that has flowed into the inlet chamber 20 flows into the bypass chamber 60 through the outlet 27.

[0043] The water to be treated flows from the inflow chamber 20 into the bypass chamber 60, where it flows downstream by gravity, then turns back and flows towards the outflow chamber 80. During this flow, the water to be treated is stirred by the bypass plate 61, which causes it to meander up, down, left, and right, allowing the flocs to come into contact with each other and grow and become coarser.

[0044] The treated water containing coarse flocs flows into the outflow chamber 80 from the inlet 81, then flows out towards the flow straightening plate 100 from the outlet 83, passes through each through-hole 111 of the flow straightening plate 100 and is then introduced into a downstream sedimentation tank (not shown) where the coarse flocs are allowed to settle.

[0045] In the floc formation process described above, if the flow rate of the water to be treated flowing in from the chemical mixing tank is low (when the inflow state measuring unit 121 detects that it is low), the control unit 120 rotates the agitator 40 at a rotational speed corresponding to the flow rate (this may involve starting from a stopped state or increasing the rotational speed from a rotating state). The rotational speed is increased as the amount of water to be treated decreases. This agitates the water to be treated, allowing a G value to be applied to the water to be treated flowing down into the bypass chamber 60, preventing a decrease in the number of contacts between flocs due to a low flow rate of water to be treated flowing down within the bypass chamber 60. This makes it possible to maintain good floc formation even when the flow rate of the water to be treated is low.

[0046] On the other hand, regardless of the flow rate of the water to be treated, by rotating the agitator 40, the pumping action of the rotating agitator 40 causes a portion of the water to be treated that has flowed from the bypass chamber 60 into the outlet chamber 80 to flow into the lower part 20B of the inlet chamber 20 via the circulation opening 31. Furthermore, the water to be treated that has flowed into the lower part 20B is introduced into the upper part 20A through the flow port 29, where it is combined with the water to be treated that is flowing in from the inlet 23, and then discharged into the bypass chamber 60 from the outlet 27.

[0047] In this way, by mixing and bringing into contact the water to be treated that flows in from the pretreatment equipment where floc formation has not yet progressed with the water to be treated that has already formed flocs in the bypass chamber 60 and is circulating from the outlet chamber 80, contact coagulation using the already formed flocs can be promoted, thereby more effectively advancing floc formation in the bypass chamber 60.

[0048] The amount of water to be treated circulated from the outflow chamber 80 to the inflow chamber 20 is adjusted by adjusting the rotation speed of the agitator 40 and the opening degree of the opening adjustment door 35. For example, if the flow rate of water to be treated flowing in from the chemical mixing tank of the pretreatment facility is high, the opening degree of the opening adjustment door 35 is increased and the rotation speed of the agitator 40 is also increased to provide a corresponding circulation flow rate. On the other hand, if the flow rate of water to be treated flowing in from the chemical mixing tank of the pretreatment facility is low, the rotation speed of the agitator 40 is increased as described above to give the water to be treated a high G value, but the opening degree of the opening adjustment door 35 is decreased to reduce the circulation flow rate.

[0049] In other words, the agitator 40 has the function of imparting a G value to the water to be treated when the inflow water volume is low to promote floc growth, and the function of increasing or decreasing the circulation flow rate of the water to be treated that is circulated from the outlet chamber 80 side (pump function, circulation function). Therefore, the operating state of the agitator 40 (and the opening degree of the opening degree adjustment door 35) is changed and controlled so that both functions can be performed effectively at the same time.

[0050] In the event that the agitator 40 is stopped, the water to be treated that flows in from the inlet 23 will flow back through the flow port 29 and attempt to flow out through the circulation opening 31 to the outlet chamber 80 via a short circuit (backflow, short-circuit flow). However, in this embodiment, a backflow prevention gate 33 is installed, so such backflow does not occur.

[0051] If a backflow prevention gate 33 is not installed, opening the opening adjustment door 35 before starting the agitator 40 will cause the treated water to backflow. Therefore, it is best to operate the system by starting the agitator (circulator) 40 first and then opening the opening adjustment door 35.

[0052] As explained above, the water purification floc formation device 1 has a folded structure for the bypass chamber 60 and is configured to place the inlet chamber 20 and outlet chamber 80 in close proximity. This allows for miniaturization and compactness of the equipment, while also allowing for a longer bypass channel to promote good floc growth. Furthermore, as mentioned above, fluctuations in the amount of treated water are unavoidable in water treatment plants. However, when the amount of treated water decreases, the agitator 40 stirs the water to be treated flowing into the inlet chamber 20, thereby providing a G value and improving the floc formation capacity in the bypass chamber 60.

[0053] Furthermore, by providing a circulation opening 31 connecting the inlet chamber 20 and the outlet chamber 80, a circulation channel is formed in which a portion of the water to be treated circulates through the inlet chamber 20, the bypass chamber 60, and the outlet chamber 80. This allows for further improvement of the floc formation process through contact coagulation, where the water to be treated flowing in from the pretreatment equipment comes into contact with the floc-formed water to be treated circulating from the outlet chamber 80.

[0054] Furthermore, since an opening adjustment mechanism consisting of an opening adjustment door 35, a drive member 37, and an opening / closing mechanism drive unit 39 is installed in the circulation opening 31, the circulation flow rate of the treated water circulated from the outlet chamber 80 to the inlet chamber 20 can be easily adjusted to a flow rate suitable for floc formation.

[0055] Furthermore, since a backflow prevention gate 33 is installed in the circulation opening 31 to prevent short-circuit flow from the inlet chamber 20 to the outlet chamber 80, it is possible to reliably prevent the water to be treated from flowing directly from the pretreatment equipment into the inlet chamber to the outlet chamber 80 in a short-circuit flow.

[0056] In the case of flocculation by bypass-flow stirring, the floc formation capacity generally decreases when the flow rate decreases compared to flocculation by mechanical stirring. However, in the floc formation device 1 according to this embodiment, even when the flow rate decreases, the G value is applied by rotating the stirring and circulation blades, and a portion of the treated water after floc formation is circulated upstream to cause contact flocculation. Therefore, the floc formation capacity is improved compared to flocculation by mechanical stirring. In other words, the ability to follow changes in the raw water conditions (turbidity, TOC) and water volume is improved.

[0057] Figures 6 to 8 are explanatory diagrams illustrating the replacement method when replacing a conventional floc forming apparatus 200 with the floc forming apparatus 1 according to this embodiment. The conventional floc forming apparatus 200 shown in Figure 6 is configured by connecting multiple (four stages in this example) floc forming apparatuses 200 in series toward the flow of the water to be treated (direction of arrow E). Each floc forming apparatus 200 is a device that forms flocs by mechanical stirring, and an agitator 203 is installed inside the floc forming tank 201 of each floc forming apparatus 200. Between each floc forming tank 201, a flow straightening plate 210 having a large number of through holes, similar to that shown in the floc forming apparatus 1 according to this embodiment, is installed. The water to be treated that flows from the pretreatment equipment flows into each floc forming apparatus 200 separated by the flow straightening plate 210, and is stirred by the slowly rotating agitator 203, causing the minute flocs to grow into larger flocs. The treated water, having passed through all the floc formation devices 200 and with flocs growing, is then introduced into the subsequent sedimentation tank.

[0058] To replace the floc forming apparatus 200 with the floc forming apparatus 1 according to this embodiment, first remove the mechanical parts such as the agitator 203 from the floc forming tank 201. Next, prepare the unitized floc forming apparatus 1 according to this embodiment as shown in Figure 7, and house it as shown in Figure 8. This completes the installation of the floc forming apparatus 1.

[0059] The floc formation apparatus 1 according to this embodiment has an inlet chamber 20 and an outlet chamber 80 arranged in close proximity, and a bypass chamber 60 has a reversal structure in which the water to be treated flows in from the inlet chamber 20 folds back and flows down to the outlet chamber 80. As a result, the entire apparatus, including the inlet chamber 20, outlet chamber 80 and bypass chamber 60, is unitized, making it possible to easily install it in existing floc formation tanks simply by replacing the internal components.

[0060] As described above, the floc forming apparatus 1 according to this embodiment has improved floc forming capacity compared to the conventional floc forming apparatus 200. While the conventional floc forming apparatus 200 required 2 to 4 rows (multiple rows) for aggregation, the floc forming apparatus 1 according to this embodiment can achieve sufficient floc formation with just one row. Consequently, the number of drive units, components, and installation area can be reduced, and civil engineering costs can be lowered during replacement work. Furthermore, the reduced number of drive units lowers the frequency of maintenance related to the drive units. Also, in this embodiment, since the agitator 40 is suspended, there are no maintenance items inside the tank, further improving maintainability. In other words, miniaturization and low life cycle cost (LCC) can be achieved.

[0061] Figure 9 is a schematic plan view of a water purification floc forming apparatus 1-2 according to another embodiment of the present invention, and Figure 10 is a schematic cross-sectional view of CC of Figure 9. In the water purification floc forming apparatus 1-2 shown in these figures, the same or corresponding parts as the water purification floc forming apparatus 1 according to the embodiment shown in Figures 1 to 8 are denoted by the same reference numerals (however, each reference numeral is denoted by the subscript "-2"). Except for matters described below, the invention is the same as the embodiment shown in Figures 1 to 8.

[0062] In this water purification floc formation device 1-2, the main differences from the water purification floc formation device 1 are the arrangement of the inlet chamber 20-2 and the outlet chamber 80-2, and the installation of a flow straightening mechanism 100-2 at the outlet 83-2 of the outlet chamber 80-2. Specifically, in this water purification floc formation device 1-2, a partition wall 26-2 is provided on the extension of the partition wall 67-2 to separate the inlet chamber 20 and the outlet chamber 80. The partition wall 26-2 is equipped with a circulation opening 31-2, a backflow prevention gate 33-2, and opening adjustment means (such as an opening adjustment door 35-2), similar to those in the water purification floc formation device 1.

[0063] In this embodiment, as with the floc formation apparatus 1, the inlet chamber 20-2 and outlet chamber 80-2 are arranged in close proximity, and the bypass chamber 60-2 has a folded structure. This allows for miniaturization and compactness of the equipment, while simultaneously allowing for a longer bypass channel to promote good floc growth. Also, as with the floc formation apparatus 1, when the amount of treated water decreases, the water to be treated flowing into the inlet chamber 20-2 is stirred by the agitator 40-2 to provide a G value, thereby improving the floc formation capacity in the bypass chamber 60-2. Furthermore, floc formation is promoted by contact coagulation due to the circulating flow from the outlet chamber 80-2.

[0064] The rectifying mechanism 100-2 is constructed by attaching a plate with numerous through holes to the outlet 83-2. By installing the rectifying mechanism 100-2 at the outlet 83-2, the outflow chamber 80-2 can also be used for rectifying, eliminating the need to install the rectifying plate 100 provided in the floc forming device 1, thereby further reducing the size of the device and the number of parts. Alternatively, the rectifying mechanism may be installed at the inlet 23 of the inflow chamber 20, and the rectifying plate 10 may be omitted.

[0065] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the claims, specification, and drawings. Furthermore, any shape or structure not directly described in the specification and drawings is within the scope of the technical idea of ​​the present invention as long as it achieves the function and effect of the present invention. For example, in each of the above embodiments, the natural flow direction in the bypass chamber was folded back once, but it may be configured to fold back two or more times so that the inlet and outlet chambers at both ends are in close proximity. In addition, the spacing between the bypass plates (bypass flow channel pitch) should be wider towards the downstream side in order to gradually reduce the stirring intensity and increase the size of the flocs (tapered flocculation).

[0066] Furthermore, in each of the above embodiments, the inlet and outlet chambers are directly arranged on both sides of the partition wall, but in some cases, the two may be connected by piping or waterways; the point is that the inlet and outlet chambers are arranged in close proximity. Also, in each of the above embodiments, control means are provided to measure and control the amount of water to be treated by the floc forming device, but the operation of the floc forming device may also be performed by human visual inspection or manual operation. Also, in each of the above embodiments, the water to be treated is circulated using stirring blades (circulating blades), but instead, a method of circulating the water from the outlet side to the inlet side using pumps or piping may be used. Furthermore, depending on the situation, the circulation path may be omitted or the installation of a stirrer may be omitted.

[0067] Furthermore, the embodiments described above and shown in the figures can be combined, provided that there is no contradiction in their purpose and structure. Also, even if only a part of the descriptions above and shown in the figures is included, each can constitute an independent embodiment, and the embodiments of the present invention are not limited to a single embodiment that combines the above descriptions and figures. [Explanation of Symbols]

[0068] 1. Flocculent Forming Apparatus for Water Purification (Flocculent Forming Apparatus) 10 Rectifier plate 20 Inflow chamber 31 Circulation opening 33 Backflow prevention gate 35. Door with adjustable opening angle (mechanism for adjusting opening angle) 37. Driving member (opening degree adjustment means) 39 Opening / closing mechanism drive unit (opening degree adjustment mechanism) 40 Agitator 60 Diversion chamber 61 Detour plate 80 Outflow chamber 100 rectifier plate 120 Control Unit 121 Inflow State Measurement Unit

Claims

1. In a floc formation apparatus for water purification used in the floc formation process of the coagulation and sedimentation treatment step of water purification, An inlet chamber into which treated water flows in from a chemical mixing tank where chemicals are mixed, A stirrer that stirs the water to be treated that flows into the aforementioned inflow chamber in such a way that it gives a G value that maintains good floc formation, A bypass chamber is provided for the water to be treated, which flows in from the aforementioned inflow chamber, and is bypassed by a bypass plate as it flows downwards. An outlet chamber for discharging the treated water flowing in from the aforementioned bypass chamber to downstream equipment, Equipped with, The inlet chamber and the outlet chamber are arranged in close proximity. A water purification floc formation apparatus characterized in that the bypass chamber has a reversal structure in which the water to be treated, which flows in from the inlet chamber, reverses direction and flows down to the outlet chamber.

2. In a floc formation apparatus for water purification used in the floc formation process of the coagulation and sedimentation treatment step of water purification, An inlet chamber into which the water to be treated from the pretreatment equipment flows in, A stirrer for stirring the water to be treated that flows into the aforementioned inflow chamber, A bypass chamber is provided for the water to be treated, which flows in from the aforementioned inflow chamber, and is bypassed by a bypass plate as it flows downwards. An outlet chamber for discharging the treated water flowing in from the aforementioned bypass chamber to downstream equipment, Equipped with, The inlet chamber and the outlet chamber are arranged in close proximity. The bypass chamber is configured with a reversal structure in which the water to be treated, which flows in from the inflow chamber, reverses direction and flows down to the outflow chamber. A water purification floc formation apparatus characterized by providing a circulation opening connecting the inlet chamber and the outlet chamber, thereby forming a circulation channel through which a portion of the water to be treated circulates in the inlet chamber, the bypass chamber, and the outlet chamber.

3. A water purification floc formation apparatus according to claim 2, A water purification floc formation apparatus characterized in that the circulation opening is equipped with an opening adjustment means for adjusting the circulation flow rate.

4. A water purification floc formation apparatus according to claim 2, A water purification floc formation apparatus characterized in that a backflow prevention gate is installed in the circulation opening to prevent short-circuit flow from the inlet chamber to the outlet chamber.

5. A water purification floc formation apparatus according to claim 2, A water purification floc formation apparatus characterized in that the circulation opening is equipped with both an opening adjustment means for adjusting the circulation flow rate and a backflow prevention gate for preventing short-circuit flow from the inlet chamber to the outlet chamber.

6. In a floc formation apparatus for water purification used in the floc formation process of the coagulation and sedimentation treatment step of water purification, An inlet chamber into which the water to be treated from the pretreatment equipment flows in, A stirrer for stirring the water to be treated that flows into the aforementioned inflow chamber, A bypass chamber is provided for the water to be treated, which flows in from the aforementioned inflow chamber, and is bypassed by a bypass plate as it flows downwards. An outlet chamber for discharging the treated water flowing in from the aforementioned bypass chamber to downstream equipment, Equipped with, The inlet chamber and the outlet chamber are arranged in close proximity. The bypass chamber is configured with a reversal structure in which the water to be treated, which flows in from the inflow chamber, reverses direction and flows down to the outflow chamber. Furthermore, this water purification floc formation device includes an inflow state measuring unit that measures the state of the amount of water to be treated, A control unit that controls the operating state of the agitator according to the state of the amount of water to be treated, as measured by the inflow state measuring unit, A floc formation apparatus for water purification, characterized by being equipped with the following features.

7. A water purification floc formation apparatus according to claim 6, The control unit is characterized in that when the amount of water to be treated decreases, it operates the agitator or increases its rotational speed, thereby providing a floc formation apparatus for water purification.

8. A water purification floc formation apparatus according to claim 2 or 3, A water purification floc formation apparatus characterized by comprising a control unit that controls the amount of water to be treated that is circulated from the outlet chamber to the inlet chamber by the pumping action of the agitator by increasing or decreasing the rotational speed of the agitator.

Images