Turbid water treatment system

Abstract

To provide a turbid water treatment system that can easily adjust an amount of a coagulant to be inputted into a thickener depending on a turbidity of turbid water.SOLUTION: A turbid water treatment system 10 comprises: supply routes L1, LS supplying turbid water MW; a classifier 12 as a removal part that removes sand gravel from the turbid water MW supplied via the supply routes L1, LS and a sedimentary sand pit 20; the supply passage LS and a supply passage L2 as a water supply route for feeding the turbid water MW in the state that at least a part of sand gravel is removed by the removal part; and a thickner 13 which separates settled slurry and clean water from the turbid water MW fed by the water supply route. In a route from the removal part to a terminal part of the water supply route, the system comprises turbidity meters 31 to 34 measuring a turbidity of the turbid water MW in the state that at least a part of sand gravel is removed by the removal part, and a coagulant, which is added to the thickner 13, is adjusted on the basis of the turbidity measured by the turbidity meters 31 to 34.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to turbid water treatment systems. [Background technology]

[0002] Patent Document 1 describes a raw water treatment device. This raw water treatment device has a raw water pit on the upstream side for supplying raw water, and a thickener on the downstream side for adding a coagulant to settle and separate flocs from the raw water. A small settling tank is provided in the piping path from the raw water pit to the thickener, and the upstream side of the thickener is connected to the downstream side of the settling tank by piping. The settling tank is equipped with a turbidity meter for measuring the turbidity of turbid water, and the turbidity of the raw water is measured by the turbidity meter inside the settling tank, and the amount of coagulant added is adjusted based on the turbidity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-221468 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the thickener must be connected to a settling tank by piping in order to adjust the amount of flocculant added to the thickener, which poses a problem that the configuration of the thickener and the like tends to become complicated.

[0005] One of the objects of the present disclosure is to provide a turbid water treatment system that can easily adjust the amount of coagulant added to the thickener according to the turbidity of the turbid water without complicating the configuration of the thickener. [Means for solving the problem]

[0006] The turbid water treatment system according to the present disclosure includes: a supply channel for supplying turbid water; A removal unit that removes gravel from the turbid water supplied through the supply path; A water supply path for supplying turbid water from which at least a portion of the gravel has been removed by the removal unit; A turbid water treatment system comprising: a thickener that separates slurry settled from the turbid water sent through the water supply path and clean water; The path from the removal section to the terminal end of the water supply path is equipped with a turbidity meter that measures the turbidity of the turbid water after at least some of the gravel has been removed by the removal section, and the amount of coagulant added to the thickener is adjusted based on the turbidity measured by the turbidity meter. [Effects of the Invention]

[0007] According to the technology disclosed herein, it is possible to easily adjust the amount of flocculant added to the thickener according to the turbidity of the turbid water without complicating the configuration of the thickener. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a muddy water treatment system according to the first embodiment. [Figure 2] FIG. 2 is a plan view showing a state in which a supply channel for muddy water is arranged above a sand settling pit. [Figure 3] FIG. 3 is a cross-sectional view of the sedimentation pit taken along line AA in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along the line BB in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each of the following [1] to [4] is an example of a turbid water treatment system included in the present disclosure. [1] a supply channel for supplying turbid water; A removal unit that removes gravel from the turbid water supplied through the supply path; A water supply path for supplying turbid water from which at least a portion of the gravel has been removed by the removal unit; A turbid water treatment system comprising: a thickener that separates slurry settled from the turbid water sent through the water supply path and clean water; The path from the removal section to the terminal end of the water supply path is equipped with a turbidity meter that measures the turbidity of the turbid water after at least some of the gravel has been removed by the removal section, and the amount of coagulant added to the thickener is adjusted based on the turbidity measured by the turbidity meter.

[0010] The turbidity treatment system described in [1] above uses a turbidity meter to measure the turbidity of the turbid water from which sand and gravel have been removed in the removal section, so the required amount of flocculant can be determined based on the turbidity measured by the turbidity meter, making it possible to easily adjust the amount of flocculant added to the thickener according to the turbidity of the turbid water.In addition, because the turbidity meter is installed in the path before the thickener, there is no need to install a turbidity meter in the thickener to measure turbidity, for example, and the configuration of the thickener can be simplified.

[0011] [2] The removal unit includes a sedimentation pit that collects the turbid water sent through the supply path and settles sand and gravel, The sedimentation pit is A muddy water storage section that stores the muddy water sent from the supply path; An overflow storage section that stores muddy water overflowing from the muddy water storage section, The turbidity meter measures the turbidity of the turbid water contained in the overflow water storage section.

[0012] The turbidity treatment system of [2] can be equipped with a turbidity meter by utilizing the configuration of the overflow collection section in the sedimentation pit.

[0013] [3] The removal unit includes a classifier that removes sand and gravel from the turbid water sent through the supply path, The turbidity meter measures the turbidity of the turbid water from which sand and gravel have been removed by the classifier.

[0014] [4] A turbid water treatment system according to any one of [1] to [3], comprising a treated water tank for storing or discharging treated water obtained from the supernatant of the thickener, and a filter press for compressing and filtering turbid water containing slurry that has settled in the thickener to separate it into a dehydrated cake and a filtrate.

[0015] First Embodiment The following description relates to a muddy water treatment system 10 according to the first embodiment.

[0016] 1. Configuration of turbid water treatment system 10 1 is a block diagram showing the schematic configuration of a turbid water treatment system 10. The turbid water treatment system 10 includes a raw water tank 11, a classifier 12, a grit pit 20, a thickener 13, a treated water tank 14, a slurry tank 15, and a filter press 16.

[0017] The raw water tank 11 stores a certain amount of turbid water MW so that raw water of the turbid water MW can be continuously treated. The turbid water MW is muddy water containing mud, sand, etc., and can be, for example, turbid water generated by tunnel excavation work, but is not limited to this, and can be turbid water generated by various construction works, drainage, etc. The turbid water MW stored in the raw water tank 11 is sent to the classifier 12 via a supply line L1 by the driving force of a pump P1.

[0018] The classifier 12 separates large and small particles contained in the turbid water MW, and various well-known classifiers can be used. For example, particle size can be separated using a classifier with a spiral or mesh structure, and large particles such as stones are discharged to the outside for disposal. Small particles including sand and mud are stored in a tank (not shown) provided in the classifier 12 and then sent to the subsequent sedimentation pit 20. For example, pebbles are removed by the classifier 12, and the turbid water MW containing sand and mud is sent to the sedimentation pit 20 via the supply line LS by the driving force of the pump PS.

[0019] FIG. 2 is a plan view of the sedimentation pit 20. FIG. 3 is a longitudinal cross-sectional view of the sedimentation pit 20. FIG. 4 is a transverse cross-sectional view of the sedimentation pit 20. The sedimentation pit 20 settles and removes relatively small particles such as sand (other than mud) from the turbid water MW supplied via the supply line LS. The sedimentation pit 20 is formed, for example, by solidifying a material such as concrete to a predetermined thickness on top of a crushed stone layer CS, which is formed by laying crushed stone to a predetermined thickness in a depression formed by digging the ground. The sedimentation pit 20 has a bottom surface 21 and partition walls 27A, 27B that stand relative to the bottom surface 21 and surround the bottom surface 21. The pit is equipped with a turbid water storage section 20A that collects turbid water MW and settles sand and the like, and an overflow storage section 20B that stores turbid water MW that overflows from the turbid water storage section 20A. The muddy water storage section 20A and the overflow water storage section 20B are separated by a partition wall 25, and the partition wall 25 restricts the movement of muddy water MW from the muddy water storage section 20A side toward the overflow water storage section 20B side.

[0020] The bottom surface portion 21 is provided in a rectangular area and, as shown in Fig. 3, has an inclined bottom surface 22 that is inclined with respect to the ground surface (ground) and a flat surface portion 23 that is approximately parallel to the ground surface (ground). The inclined bottom surface 22 and the flat surface portion 23 are integrally continuous with each other at a predetermined obtuse angle. In this embodiment, the flat surface portion 23 is parallel to the ground surface, but this is not limited thereto, and the flat surface portion 23 may be a gently inclined surface with a smaller inclination angle with respect to the ground surface than the inclined bottom surface 22.

[0021] The turbid water storage section 20A includes a bottom surface 21, a partition wall 25 rising from the rear side of the bottom surface 21, and partition walls 27A, 27A rising from both the left and right sides of the bottom surface 21. In the turbid water MW stored in the turbid water storage section 20A, relatively large gravel particles (particles such as sand) settle due to their weight and accumulate on the bottom surface 21. The gravel particles that settle on the inclined bottom surface 22 provided on the front side (approximately half) of the bottom surface 21 accumulate on the inclined bottom surface 22, and the inclination of the inclined bottom surface 22 makes it easy for the gravel particles to move toward the flat surface 23.

[0022] As shown in FIG. 2, the supply passage LS is arranged at an angle (45 degrees left to right relative to the front-to-rear direction) that is inclined to the side relative to the longitudinal direction (front-to-rear direction) of the muddy water storage section 20A in this embodiment. The angle of the supply passage LS is not limited to this, and it can be arranged at any angle relative to the front-to-rear direction. The tip of the supply passage LS from which the muddy water MW flows out is arranged within the area on the inclined bottom surface 22. In this embodiment, the tip of the supply passage LS is arranged near the center of the inclined bottom surface 22, but this is not limited to this, and the tip of the supply passage LS may be arranged in another position.

[0023] A plurality of guide rails 24 (three in this embodiment) are formed in a line on the bottom surface portion 21. The guide rails 24 guide the traveling direction of a wheel loader, which serves as a cleaning machine for cleaning and recovering sand and gravel particles, and extend parallel to the front-to-rear direction (longitudinal direction; left-to-right direction in Figure 2) of the sedimentation pit 20. Particles that settle in the turbid water storage section 20A and accumulate on the bottom surface portion 21 are recovered by the wheel loader traveling along the guide rails 24 and discharged outside the sedimentation pit 20.

[0024] As shown in FIG. 3, the overflow storage section 20B is composed of a bottom surface 29 provided at the rear end of the bottom surface section 21, a partition wall 25 standing on the front side of the bottom surface 29, a partition wall 27B standing on the rear side of the bottom surface 29, and the rear ends of partition walls 27A and 27A standing on both the left and right sides of the bottom surface 29. The turbid water storage section 20A and the overflow storage section 20B are separated by the partition wall 25. An overflow passing recess 26 through which overflow water passes is formed at the upper end of the partition wall 25. The overflow passing recess 26 is provided at a predetermined depth in the middle of the upper end of the partition wall 25 in the left-right direction. When the surface (upper surface) of the turbid water MW stored in the turbid water storage section 20A exceeds the height of the bottom surface of the overflow passing recess 26, the turbid water MW from the turbid water storage section 20A flows through the overflow passing recess 26 into the overflow storage section 20B. The turbid water MW accommodated in the overflow accommodating section 20B is sent to the thickener 13 via the water supply passage L2 by the driving force of the pump P2.

[0025] The thickener 13 stores turbid water MW and separates it from clean water by injecting a coagulant (e.g., polyaluminum chloride, polymer coagulant, etc.) to cause the slurry in the coagulated turbid water MW to settle. The coagulant converts the fine suspended solids in the water into larger particles that adsorb each other, causing them to settle. Within the thickener 13, the suspended solids, which are fine solid particles in the turbid water MW, settle and separate the slurry into a concentrated slurry and a supernatant liquid (clean water) from which a certain amount of the fine solid particles have been removed. A sludge scraper is installed at the bottom of the thickener 13. The slurry that settles to the bottom of the thickener 13 is scraped toward the center by the sludge scraper and sent to the slurry tank 15. The supernatant liquid in the upper layer of the thickener 13 is sent to the treated water tank 14 via the water supply line L3 using the driving force of pump P3.

[0026] The treated water tank 14 in Figure 1 stores or discharges the treated water obtained as the supernatant from the thickener 13. After being temporarily stored in the treated water tank 14, the treated water is discharged into a river or the like. The slurry tank 15 temporarily stores surplus slurry. The slurry stored in the slurry tank 15 is sent to the filter press 16 via a discharge line L4 by the driving force of a pump P4.

[0027] The filter press 16 dehydrates the slurry by forcing it between the filter plate and the filter cloth, forming a cake which is a plate-like sludge, and compresses and filters the turbid water MW containing the slurry that has been coagulated and settled in the thickener 13 to separate it into a dehydrated cake and filtrate. The cake is discharged to a predetermined location below, and the filtrate squeezed out at that time is returned to the raw water tank 11 via the return line L5 by the driving force of the pump P5.

[0028] The raw water tank 11, the overflow storage section 20B of the settling pit 20, the thickener 13, the slurry tank 15, and the treated water tank 14 are equipped with water level gauges (not shown). Each pump P1 to P5, PS starts operating when the water level detected by the water level gauge rises to a preset operating level, and stops operating when the water level drops to a preset stop level.

[0029] 2. Turbidity meter configuration The turbid water treatment system 10 includes a sand settling pit 20 and a classifier 12 as removal units that remove sand and gravel from the turbid water MW supplied via the supply lines L1 and LS in Fig. 1. The turbid water MW from which at least a portion of the sand and gravel has been removed by the classifier 12 and the sand settling pit 20 is sent to a thickener 13 via the supply line LS and the water supply line L2 as water supply paths. A plurality of turbidity meters 31-34 are provided on the path from the removal unit to the terminal end of the water channel L2 (the water channel L2 upstream of the thickener 13). The turbidity meters 31-34 are devices that measure turbidity, which is the amount of turbid substances in a liquid (degree of turbidity). They measure the turbidity of turbid water MW (turbid water from which at least some of the gravel has been removed by the removal unit) by detecting the optical characteristics of turbidity caused by suspended particles and colloidal substances in the liquid. For example, by using a sensor to separate and detect light incident from a light source into transmitted light and scattered light, the ratio of transmitted light to scattered light, which changes depending on the turbidity in the liquid, can be calculated to calculate turbidity. The turbidity meters may also include a concentration meter that measures the concentration of turbid water.

[0030] In this embodiment, multiple turbidity meters 31-34 are provided between the classifier 12 and the sedimentation pit 20 as the removal unit and the thickener 13 (upstream side). Specifically, the turbidity meter 31 is disposed in the classifier 12 (or immediately after the classifier 12) and is provided in the tank of the classifier 12 where the turbidity water MW is stored, the turbidity meter 32 is provided in the supply line LS, the turbidity meter 33 is provided in the overflow storage unit 20B in the sedimentation pit 20 (see FIG. 3; the communication line for the turbidity meter 33 is omitted in FIG. 3), and the turbidity meter 34 is provided in the water supply line L2. Note that the number of turbidity meters is not limited to this, and for example, a configuration including one or more of these turbidity meters may be used. Each of the turbidity meters 31-34 measures the turbidity of the turbidity water MW when it is stored or when it passes through the installation location. The turbidity measured by one or more turbidimeters 31-34 is input to, for example, a control device via wired or wireless communication means, and the amount of coagulant added to the thickener 13 can be adjusted according to the control signal output from the control device.

[0031] 3.Muddy water treatment process Raw water (water to be treated) discharged from a construction site or the like is transported to the raw water tank 11 and stored therein. The turbid water MW stored in the raw water tank 11 is sent to the classifier 12 via a supply line L1, where pebbles and other particles are removed, and the turbid water MW is then stored in the tank of the classifier 12. The turbid water MW stored in the tank is supplied to the turbid water storage section 20A of the grit pit 20 via a supply line LS. The turbid water MW, from which particles such as sand have been removed in the turbid water storage section 20A, accumulates in the turbid water storage section 20A, and when the height of the upper surface of the turbid water MW exceeds the bottom surface of the overflow passage recess 26 of the partition wall 25, it flows through the overflow passage recess 26 (overflowing the partition wall 25) into the overflow storage section 20B.

[0032] The turbid water MW contained in the overflow container 20B is sent to the thickener 13 via the water supply line L2. The turbid water MW is separated into supernatant purified water and settled slurry in the thickener 13. At this time, the flocculant binds together the fine solid particles contained in the turbid water MW, promoting the settling of the slurry. The supernatant liquid (purified water) separated in the thickener 13 is sent to the treated water tank 14 via the water supply line L3, and is discharged from this treated water tank 14 into the natural water system. Meanwhile, the slurry that has settled in the thickener 13 is sent to the filter press 16 via the slurry tank 15, where it is dewatered to form a cake.

[0033] 4.Example of effects The turbid water treatment system 10 includes supply lines L1, LS for supplying turbid water MW, a classifier 12 and a sand settling pit 20 as removal units for removing sand and gravel from the turbid water MW supplied via the supply lines L1, LS, a supply line LS and a water conveyance line L2 as water conveyance paths for conveying the turbid water MW from which at least a portion of the sand and gravel has been removed by the removal unit, and a thickener 13 for separating the slurry settled from the turbid water MW conveyed via the water conveyance path from the clean water. The path from the classifier 12 and the sand settling pit 20 as removal units to the terminal end of the water conveyance path is provided with turbidity meters 31-34 for measuring the turbidity of the turbid water MW from which at least a portion of the sand and gravel has been removed by the classifier 12 and the sand settling pit 20 as removal units, and the amount of flocculant added to the thickener 13 is adjusted based on the turbidity measured by the turbidity meters 31-34.

[0034] The turbidity of the turbid water MW from which at least a portion of the gravel has been removed by the classifier 12 and the sedimentation pit 20 as the removal unit is measured by the turbidity meters 31-34, so the required amount of flocculant can be determined based on the turbidity measured by the turbidity meters 31-34, and it becomes possible to easily adjust the amount of flocculant to be added to the thickener 13 according to the turbidity of the turbid water MW. Furthermore, because the turbidity meters 31-34 are provided in the path before reaching the thickener 13 after the gravel has been removed, there is no need to provide the turbidity meters 31-34 in the thickener 13 or in a configuration connected to the thickener 13 with pipes for measuring turbidity, for example, and the configuration of the thickener 13 can be simplified.

[0035] The removal section includes a sedimentation pit 20 that collects the turbid water MW sent through the supply line LS and settles the sand and gravel. The sedimentation pit 20 includes a turbid water storage section 20A that stores the turbid water MW sent from the supply line LS and an overflow storage section 20B that stores the turbid water MW that overflows from the turbid water storage section 20A. A turbidity meter 33 measures the turbidity of the turbid water MW stored in the overflow storage section 20B.

[0036] A turbidity meter 33 can be installed by utilizing the configuration of the overflow accommodating section 20B in the sedimentation pit 20.

[0037] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiments may be modified as follows.

[0038] In the above embodiment, one sand settling pit 20 is provided, but this is not limiting and multiple sand settling pits 20 may be provided. For example, multiple consecutive sand settling pits 20 may be provided, and the turbid water MW in the overflow water storage section 20B of one sand settling pit 20 may be sent to the turbid water storage section 20A of the next sand settling pit 20 via a water supply channel.

[0039] Although the configuration is such that the turbid water MW is sent directly from the settling pit 20 to the thickener 13, this is not limited to this. For example, a storage tank for storing the turbid water MW may be provided between the settling pit 20 and the thickener 13, and the turbid water MW in the overflow storage section 20B may be temporarily stored in the storage tank, and then the turbid water MW in the storage tank may be sent to the thickener 13.

[0040] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0041] 10: Turbid water treatment system 11: Raw water tank 13: Thickener 14: Treatment tank 16: Filter press 20: Sand pit 20A: Muddy water storage section 20B: Overflow containment section 21: Bottom part 22: Slanted bottom surface 23: Plane part 24: Guide rail 25: Partition wall 26: Overflow passage recess 27A,27B: Bulkhead

Claims

1. a supply channel for supplying turbid water; A removal unit that removes gravel from the turbid water supplied through the supply path; A water supply path for supplying turbid water from which at least a portion of the gravel has been removed by the removal unit; A turbid water treatment system comprising: a thickener that separates slurry settled from the turbid water sent through the water supply path and clean water; The turbid water treatment system is equipped with a turbidity meter on the path from the removal unit to the terminal end of the water supply path, which measures the turbidity of the turbid water after at least some of the gravel has been removed by the removal unit, and the amount of coagulant added to the thickener is adjusted based on the turbidity measured by the turbidity meter.

2. The removal unit includes a sedimentation pit that collects the turbid water sent through the supply path and settles sand and gravel, The sedimentation pit is A muddy water storage section that stores the muddy water sent from the supply path; An overflow storage section that stores muddy water overflowing from the muddy water storage section, The turbidity treatment system according to claim 1, wherein the turbidity meter measures the turbidity of the turbid water contained in the overflow container.

Images