JP2012143702A - Muddy water treatment system and muddy water treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system that treats muddy water without using chemicals, reuses dehydrated cake, and performs control such that water is discharged only when an SS concentration is not more than an environmental standard value related to water pollution for water discharge to rivers and that the water is not discharged when the SS concentration is high.SOLUTION: This system includes: a first filter 22 capturing a part of particles contained in the muddy water, and sending out first treated water; a second filter 23 capturing particles remaining in the first treated water, and discharging second treated water; a differential pressure measurement means 24 for measuring a differential pressure between the first treated water and the second treated water; and solenoid valves 26, 27 stopping the discharge of the second treated water and discharging the second treated water to a return line 25 returning the water to the upstream of the first filter 22, when the measured differential pressure is less than a first set value or exceeds a second set value higher than the first set value.

Description

  The present invention relates to a muddy water treatment system and a muddy water treatment method capable of treating construction muddy water without using any chemicals such as a flocculant.

  Construction muddy water generated in dam construction, tunnel construction, and the like is treated by a turbid water treatment apparatus using a coagulation sedimentation method and a muddy water treatment facility including this sludge dewatering apparatus (for example, see Patent Document 1). This muddy water is generated when the spring water generated at the construction site is mixed with earth and sand, or is generated due to excavation, shear transport, shotcrete, concrete placement, washing water, and the like.

  Here, FIG. 1 shows an example of turbid water treatment equipment conventionally used. Construction muddy water contains gravel, sand and mud as particles. For this reason, in order to settle particles having a relatively large particle size and perform solid-liquid separation, the particles are first supplied to the sand settling tank 10. The sand settling tank 10 stores a fixed amount so that continuous treatment is possible, and separates gravel and sand having a relatively large particle diameter from muddy water. In the sand settling tank 10, the gravel and sand are naturally settled, so that the gravel and sand gather at the bottom, and the supernatant liquid is separated as muddy water.

  Thereafter, the supernatant liquid is sent to the turbid water treatment device 11, and the pH and turbidity of the supernatant liquid are measured. When an alkaline component substance such as cement is included, the pH becomes high. Therefore, a neutralizing gas such as carbon dioxide gas is injected before flowing into the turbid water treatment apparatus 11 to neutralize the liquid. Thereafter, an aggregating agent such as polyaluminum chloride, aluminum sulfate, or ferric sulfate is added to form an aggregate having a small particle size. Further, in the turbid water treatment apparatus 11, a polyacrylamide polymer flocculant or the like is added, whereby aggregates having a small particle diameter are collected and a large aggregate (floc) is formed.

  The muddy water treatment device 11 includes a coagulation sedimentation tank (thickener) 12 in order to ensure the floc sedimentation time. In the coagulation sedimentation tank 12, the supernatant liquid to which the two coagulants are added is separated into the upper layer upper water and the lower layer aggregated floc.

  The water overflows from the coagulation sedimentation tank 12 and is sent to the discharge water tank 13 where the pH is measured with a pH meter and the turbidity is measured with a turbidimeter. The measured turbidity is converted into an SS amount by the correlation formula of, and if it is a pH value and an SS amount satisfying the discharge standard, it is discharged into a river or the like. When the pH value or the SS amount does not satisfy the discharge standard, the pH is returned to the sand settling tank 10 as indicated by the broken line, and the pH is adjusted.

  On the other hand, the floc precipitated in the coagulation sedimentation tank 12 is sent to the sludge storage tank 14 and a chemical such as a dehydrating agent is added to facilitate solid-liquid separation. Thereafter, the flocs are sent to a sludge dewatering device 15 such as a filter press and compressed and filtered to separate a dehydrated filtrate and a dehydrated cake. Since the dehydrated cake contains a dehydrating agent and a flocculant and may have a high water content, a predetermined strength may not be obtained. For this reason, since it is generally difficult to reuse, it is generally disposed of as industrial waste. On the other hand, the dehydrated filtrate is returned to the sand settling tank 10.

  In addition, as a device for treating muddy water, a filtering device for filtering muddy water has been proposed (see, for example, Patent Documents 2 to 4). These filtration devices are provided with a filter, and the contaminant is separated from the turbid water by capturing the contaminant in the filter. Since these filters are gradually clogged and the differential pressure becomes higher, when the measured differential pressure reaches a set value, it is replaced with a new filter or washed.

JP 2007-307515 A JP 2009-255012 A JP 2010-119936 A Japanese Patent No. 4051260

  The treated water after being treated with the turbid water treatment device is generally drained to rivers, etc., with the pH value and SS amount being below the environmental standard value related to water pollution for discharge to rivers, During the treatment, since the above-mentioned flocculant is used, if it is discharged into a river or the like having a rich natural environment, the river or the like is contaminated. Therefore, it is preferable not to use such drugs. This is because chemicals remain in the discharge water and there is concern about the impact on the river environment.

  When the flocculant is used, it is necessary to secure the floc settling time, and therefore, it is necessary to provide the coagulation sedimentation tank 12. As a result, the turbid water treatment apparatus is enlarged, a large installation space is required, and the apparatus cost is high. There was a problem of becoming.

  In addition, the use of a dehydrating agent is also a drug, and if it remains, there is a concern about the influence on the river environment and the like if it remains. A dehydrated cake dehydrated with a dehydrating agent is difficult to reuse, and is disposed of as industrial waste, so disposal costs are incurred.

  Therefore, it is possible to treat turbid water without using chemicals such as flocculants and dehydrating agents, recycle dehydrated cakes, and can be reduced in size and provided at low cost, making maintenance easy. It has been desired to provide a system and method that can be used.

  Therefore, soil particles can be captured and separated using a filtration apparatus including the above-described filter. Some filters have a large number of holes and have various hole diameters. Since the large pore size allows many particles to pass through, it is not possible to make the SS concentration below the environmental standard value (water type is AA, A, B type: 25ppm) related to water pollution for discharge to the river. difficult. On the other hand, by reducing the pore diameter, it is possible to make the SS concentration below the environmental reference value. However, the resistance at the filter is increased, the processing amount is greatly reduced, and clogging is likely to occur. This must be changed or cleaned frequently.

  It is desired to provide an apparatus that can discharge at an SS concentration not more than the above environmental standard value and can be provided at low cost without using a filter having such a large number of small holes. Yes.

  In order to solve the above-mentioned problem, the present invention captures a part of particles contained in muddy water, sends a first treated water from which the mud made of the captured particles is separated, and a first treatment. The second separation means for capturing particles remaining in the water and discharging the second treated water from which the remaining particles have been separated; the first treated water flowing into the second separation means; and the second separation means for discharging the second treated water. Differential pressure measuring means for measuring the differential pressure with the second treated water, and when the measured differential pressure is not less than the first set value and not more than the second set value, it is discharged to a river or the like, When less than one set value or more than the second set value, a configuration including a switching unit that switches the delivery direction of the second treated water to a return line that returns to the upstream side of the first separation unit is adopted.

  The first separation means captures and separates some of the particles contained in the muddy water as a primary treatment so as to reduce the particles contained in the muddy water flowing in. The first separation means has a plurality of holes for allowing water to pass through and capturing some of the particles. As the first separation means, for example, a natural palm fiber filter can be used, and after it becomes unusable, it can be effectively used as a greening base material or the like in the field.

  As a secondary treatment, the second separation means captures the remaining particles, and sends the SS concentration to the environmental reference value or lower. By these two separation means, it is possible to treat turbid water without using a chemical such as a flocculant or a dehydrating agent. Also, the above mud is collected and dehydrated to obtain a dehydrated cake. Can be reused.

  The second separation means is a screen composed of a wire mesh having a predetermined mesh size, and a relatively large particle is first captured on the screen surface, and then a small particle is deposited to form a particle layer with a constant thickness. The formed particle layer serves as a filter, and is captured at two stages of the screen and the particle layer, so that it becomes possible to send the particles below the environmental standard value. In the present invention, the differential pressure when the particle layer is formed is set as the first set value, and the differential pressure when the particles are deposited and needs cleaning is set as the second set value, and the differential pressure is set as the first set value. When the value is between the value and the second set value, the second treated water is discharged to the river or the like, and otherwise, the second treated water can be returned through the return line.

  In this way, the differential pressure is measured by the differential pressure measuring means, and the high-concentration SS is temporarily delivered after cleaning by controlling the switching between the treated water discharged by the switching means and the treated water to be returned. However, since the differential pressure is smaller than the first set value, it is returned through the return line, so that it can be prevented from being discharged into a river or the like, and the natural environment can be prevented from being affected.

  The second separation means includes a hollow cylindrical container having a receiving nozzle for receiving the first treated water, a discharge nozzle for discharging the second treated water, and a cylindrical filter disposed in the container. It can be set as the structure containing. The second separation means includes, on the inner surface of the filter, a first particle layer composed of particles contained in the captured first treated water, and particles having a particle size smaller than the particles constituting the first particle layer. The second particle layer is formed, and the particles contained in the first treated water are captured and separated using the first particle layer and the second particle layer together with the filter.

  The second separation means may further include a cleaning means for sucking and removing the mud composed of particles deposited on the inner surface of the cylindrical filter. As this cleaning means, for example, a suction nozzle disposed in the vicinity of the mud deposited on the inner surface of the above cylindrical filter, and a suction nozzle that is continuous with the suction nozzle and rotatably disposed on the central axis of the container, A cylinder that is movable in the longitudinal direction of the container, a chamber that is continuous with the cylinder and has an expanded diameter compared to the diameter of the cylinder, and mud that is continuous with the chamber and opens the chamber to the atmosphere A discharge valve and movable means for rotating the cylinder and moving it in the longitudinal direction of the container can be provided.

  The muddy water treatment system further includes a concentration measuring means for measuring the concentration of suspended solids in the second treated water discharged from the second separation means. In this case, the switching means is measured by the differential pressure measuring means. When the differential pressure is greater than or equal to the first set value and less than or equal to the second set value, and the suspended matter concentration measured by the concentration measuring means is less than or equal to the threshold value, it is discharged to a river or the like, and the differential pressure is less than the first set value Alternatively, when the second set value is exceeded, or when the suspended solid concentration exceeds the threshold value, the delivery direction of the second treated water is switched to the return line that returns to the upstream side of the first separation means.

  Note that this system includes only the concentration measuring means, measures only the suspended matter concentration, and the switching means determines whether the measured concentration is equal to or less than the threshold value, and the second treated water. It is also possible to switch the sending direction.

  Moreover, the dehydration container which receives the mud which consists of the particle | grains isolate | separated by the 1st isolation | separation means, and removes the water | moisture content contained in the mud by sucking the gas in the dehydration container can be further included. As a method for removing water contained in the mud, besides using this dewatering device, a method of filling the water-permeable bag with mud and dehydrating the bag, and a method of drying in the sun can be exemplified.

  The dehydrating apparatus can include gas suction means such as a vacuum pump for sucking air and water vapor in the dehydration container. As the inside of the dewatering container is sucked, the water contained in the mud vaporizes, and the mud can be dried by sucking it. In order to promote this drying, a heating device such as a magnetron or a far infrared heater can be employed. Further, it is possible to send compressed gas into the dehydration container, vaporize moisture into the compressed gas, and suck it by the above gas suction means to promote drying. For this purpose, compressed gas supply means such as an air compressor Can be provided.

  The dewatering container is disposed to be inclined with respect to the horizontal direction, and a means for conveying the mud is provided in the dewatering container by inserting mud from above, sliding the dewatering container, and taking out from below. There is no need.

  In the present invention, a muddy water treatment method using this system can also be provided. In this method, a part of particles contained in turbid water is captured by the first separation means, the first treated water from which the mud consisting of the captured particles is separated, and the first treatment by the second separation means. Capturing the particles remaining in the water and discharging the second treated water from which the remaining particles have been separated; the first treated water flowing into the second separating means; and the second discharged from the second separating means. The step of measuring the differential pressure with the treated water, and if the measured differential pressure is greater than or equal to the first set value and less than or equal to the second set value, it is discharged to a river or the like and less than the first set value or the second set value When exceeding a value, the process of switching the sending direction of 2nd treated water to the return line returned to the upstream of the 1st separation means is included.

  In addition to these steps, a step of forming a first particle layer, a step of forming a second particle layer, a step of sucking and removing mud composed of particles deposited on the inner surface of the filter, and a first separation means A step of transporting the captured and separated mud by a transporting means, and a step of removing moisture contained in the mud by a dewatering device that includes a dewatering container that receives the mud and sucks the gas in the dewatering container. .

The figure which showed the structure of the conventional muddy water treatment facility. The figure which illustrated the composition of the muddy water treatment system of the present invention. The figure which showed the structural example of the 2nd separation means used for a muddy water processing system. The figure which illustrated the layer formed on the 2nd filter as the 2nd separation means. The figure which illustrated another composition of the muddy water processing system. The figure which showed one structural example of the dehydration apparatus used for a muddy water processing system. The figure which showed the detail of the dehydration apparatus shown in FIG. The figure which illustrated the gas suction means used for a dehydrator. The figure which showed another structural example of the dehydration apparatus. The figure which illustrated further another composition of the muddy water treatment system.

  The muddy water treatment system of the present invention is a system that is friendly to the natural environment, and realizes zero emission (zero waste). FIG. 2 is a diagram showing one configuration example of the muddy water treatment system.

  In dam construction and tunnel construction, spring water is generated, and this spring water is mixed with the earth and sand generated by excavation. Turbid water is generated. The muddy water includes a part of cement material by concrete spraying, etc., but most of it is earth and sand. In order to continuously operate the muddy water treatment system, muddy water is once stored in a raw water tank (not shown). By storing in the raw water tank, gravel and sand having a relatively large particle size are precipitated and separated.

  The soil particles having a small particle diameter constitute muddy water together with water and are supplied into the system shown in FIG. The muddy water treatment system includes muddy water supply means 20 such as a high-pressure pump, and muddy water is pumped by the muddy water supply means 20. The turbid water pumped by the turbid water supply means 20 passes through the pipe 21 and is supplied to the first filter 22 as the first separation means. A return line, which will be described later, is connected to the pipe 21.

  In addition, when supplying turbid water into a system, pH can be adjusted as needed. Muddy water generated in dam construction and tunnel construction is almost neutral or alkaline in many cases. In the case of exhibiting alkalinity, carbon dioxide gas can be injected to neutralize the liquid. Since the pH value of the general drainage standard value is 5.8 to 8.6, carbon dioxide gas can be injected so as to fall within this range. As the neutralizing agent, dilute sulfuric acid can be used in addition to carbon dioxide gas.

  The first filter 22 as the first separation means has a plurality of holes for allowing water to pass therethrough and capturing particles contained in the turbid water. For example, a natural palm fiber filter can be used. This palm fiber filter captures and separates particles from turbid water containing, for example, about 3000 ppm of particles, and separates the first treated water, which is treated water having a particle concentration of about 500 to 1000 ppm, into the second separation on the downstream side. It is sent to the second filter 23 as means. The palm fiber filter can remove the mud made of particles adhering to the surface and can be reused, but the function as a filter decreases with use. And finally, it cannot be reused. However, since this palm fiber can be effectively used as a greening base material or the like in the field, it will not become industrial waste.

  When the particles trapped in the palm fiber filter are accumulated to some extent, the filter is taken out, the mud made of particles adhering to the surface is removed, and is transported to the dehydrator by the transport means described later. In the dewatering device, the conveyed mud is dewatered for reuse.

  The palm fiber filter is formed by, for example, forming 100% natural palm fiber into a cylindrical shape and wrapping it with a net made of the same natural palm fiber, adsorbing soil particles in muddy water, and filtering muddy water. Can do. This filter has a high filtration performance with an average reduction rate of turbidity of about 45%, and saves about 30 to 50% of space compared to a sand basin generally used for separating water and sediment. Can be planned.

  The water passing through the filter is arranged so that the longitudinal direction of the cylindrical filter is the same as the longitudinal direction of the filter, and can be performed in the longitudinal direction, or the longitudinal direction of the filter as shown in FIG. It can arrange | position so that a water flow direction may become perpendicular | vertical, and can carry out toward the other side from the one side of the horizontal direction of a filter side surface. FIG. 2 shows that three cylindrical filters are installed adjacent to each other.

  Further, the water flow can be performed from the lower side to the upper side in the vertical direction of the filter side surface. Thus, the water flow in the vertical direction is preferable in that the soil particles captured on the lower surface of the filter naturally settle, thereby reducing the clogging of the filter and, as a result, reducing the frequency of filter replacement. In this case, the configuration of the first filter 22 is a configuration in which a plurality of palm fiber filters are arranged in the central portion of the container, muddy water is supplied to the lower portion thereof, and the muddy water moves while filtering the palm fiber filter in the upper direction. can do.

  The second filter 23 is a screen composed of a wire mesh having a predetermined mesh size, and a screen composed of a combination of two or more wire meshes having different mesh sizes is preferable. In order to capture and separate relatively small particles, a wire mesh of 10 to 30 mesh having some fine holes is necessary. However, since a wire mesh of such a mesh size has low strength, it is sent to the second filter 23. There is a case where the first treated water is broken due to bending or the like. For this reason, for example, a screen having a high strength such as a 1 to 5 mesh wire mesh or a wire mesh having a hole larger than this, and sandwiched and reinforced by these is preferable.

  Here, with reference to FIG. 3, one structural example of a 2nd separation means is demonstrated. The second separating means includes a hollow cylindrical container 30 and a second filter 23 disposed in the container 30 and formed in a hollow cylindrical shape. The container 30 includes a receiving nozzle 31 that receives the first treated water, and a discharge nozzle 32 that captures particles contained in the first treated water and discharges the second treated water after separation.

  The first treated water received from the receiving nozzle 31 is sent to the inside of the second filter 23, and passes through the second filter 23 from the inner surface to the outer surface, thereby capturing particles contained in the first treated water. And separated. Thereafter, the treated water that has passed through the second filter 23 is sent to the space formed between the second filter 23 and the container 30 as the second treated water, and is discharged from the discharge nozzle 32.

  Particles accumulate on the inner surface of the second filter 23 by the passage of the first treated water to form a particle layer. When a particle layer with a certain thickness is formed, the particle layer has an effect as a filter. The second filter 23 and this particle layer have an SS concentration lower than the environmental standard value, and are discharged as second treated water. Can be released into rivers.

  On the other hand, if time passes and the thickness of a particle layer exceeds predetermined thickness, this will become resistance and will not be able to process a predetermined amount of muddy water. For this reason, it is necessary to remove mud made of particles accumulated on the second filter 23. The second separation means can include a cleaning means for removing the mud.

  In the embodiment shown in FIG. 3, the cleaning means is continuous with the suction nozzle 33 disposed adjacent to the mud deposited on the inner surface of the second filter 23 disposed inside the container 30, and the suction nozzle 33. A cylindrical body 34 rotatably disposed on the central axis of the container 30 and movable in the longitudinal direction of the container 30; and a diameter that is continuous with the cylindrical body 34 and that is larger than the diameter of the cylindrical body 34. A chamber 35 that is an expansion chamber, a mud discharge valve 36 that is continuous with the chamber 35 and opens the atmosphere inside the chamber 35, and a movable means 37 that rotates the cylinder 34 and moves it in the longitudinal direction of the container 30. It is configured to include.

  This cleaning means is activated when it is time to clean the second filter 23, opens the mud discharge valve 36, and opens the chamber 35 to the atmosphere. The first treated water is supplied into the container 30 at a predetermined water pressure exceeding the atmospheric pressure, for example, 0.5 to 2 MPa, and the suction nozzle 33 enters the chamber 35 that is set to the atmospheric pressure via the cylindrical body 34. Because of the communication, the suction nozzle 33 has a strong suction effect. Since the suction nozzle 33 is disposed in the vicinity of the mud accumulated on the inner surface of the second filter 23, the suction nozzle 33 sucks the mud, and the cylinder 34 is rotated by the movable means 37 to move in the longitudinal direction of the container 30. Therefore, the mud accumulated on the entire inner surface of the second filter 23 is removed by suction.

  The mud sucked by the suction nozzle 33 is sent into the chamber 35 through the cylindrical body 34 and extracted through the mud discharge valve 36. Two or more suction nozzles 33 can be provided in the cylindrical body 34, and the movable means 37 rotates the cylindrical body 34 in a fixed direction around the central axis of the container 30 and a slider mechanism that moves in the longitudinal direction of the container 30. And a rotation mechanism. These can be driven by an electric motor.

  Referring to FIG. 2 again, the muddy water treatment system is configured to measure the differential pressure between the upstream flow and the downstream flow of the second filter 23 in addition to the first filter 22 and the second filter 23 described above. And a control means (not shown) for determining whether to discharge the second treated water to a river or the like according to the differential pressure, or to return to the upstream side of the first filter 22 through the return line 25, and a signal from the control means The electromagnetic valves 26 and 27 as switching means for switching the direction in which the second treated water is sent out are configured.

  The differential pressure measuring means 24 is a differential pressure gauge, and measures the difference between the water pressure of the first treated water supplied to the second filter 23 and the water pressure of the second treated water discharged from the second filter 23. This differential pressure measuring means 24 holds the differential pressure when the particle layer having a constant thickness is formed as the first set value, and holds the differential pressure when cleaning the second filter 23 as the second set value. To do. The first set value is a value smaller than the second set value, for example, a value of 0.05 to 0.2 MPa. The second set value is, for example, a value of 0.5 to 1 MPa. These values can be determined according to environmental standard values.

  The environmental standard value is 25 ppm if it is an environmental standard value related to water pollution for discharge into the SS river, and 1 ppm if it is an environmental standard value related to water pollution for discharge to lakes (water type is AA type) Or 5 ppm (the water type is A or B).

  When the second filter 23 is new or immediately after cleaning, the differential pressure measuring means 24 measures a value less than the first set value. This is because a particle layer having a certain thickness has not yet been formed on the inner surface of the second filter 23. The first treated water that has passed through the first filter 22 contains relatively large particles and fine particles. When the first treated water is passed through the second filter 23 when it is new or just after cleaning, the fine particles pass. However, relatively large particles are captured and deposited.

  For this reason, as shown in FIG. 4, the first particle layer 40 composed of relatively large particles is first formed on the inner surface of the second filter 23. When the first particle layer 40 is formed, water flows between the particles, and the particles constituting the first particle layer 40 have a relatively large particle diameter, so that there is a large gap between the particles. Finer particles pass with water. For this reason, SS concentration cannot be made below the environmental standard value.

  Thereafter, particles having a smaller particle diameter are captured on the first particle layer 40, and as shown in FIG. 4, second particles composed of particles smaller than the particle diameter of the particles constituting the first particle layer 40. Layer 41 is formed. Since the particles constituting the second particle layer 41 have a sufficiently small particle diameter, the gap between the particles is reduced and most of the particles are captured. For this reason, SS density | concentration can be made below into an environmental reference value, and the differential pressure when this 2nd particle layer 41 is formed can be set as a 1st setting value.

  Thereafter, each time the first treated water is continuously supplied, as shown in FIG. 4, particles having various particle sizes are captured on the second particle layer 41, and the particles having various particle sizes are collected from the particles having various particle sizes. Thus, the third particle layer 42 is formed. The thickness of the third particle layer 42 increases with time, and when the differential pressure reaches the second set value, the third particle layer 42 is cleaned by the cleaning means. Although the first particle layer 40 and the second particle layer 41 are also removed by this cleaning, the first particle layer 40 and the second particle layer 41 are formed by supplying the first treated water again. be able to.

  The second treated water that has passed through the second filter 23 can be discharged into a river or the like by the control means when the differential pressure measuring means 24 measures the differential pressure between the first set value and the second set value. Then, the electromagnetic valve 26 on the discharge side is opened, the electromagnetic valve 27 attached to the return line 25 is closed, and the electromagnetic valve 27 is discharged to a river or the like. On the other hand, when the differential pressure measuring unit 24 measures a differential pressure less than the first set value, the first particle layer 40 and the second particle layer 41 are not yet formed. Therefore, the electromagnetic valve 27 is opened so as to return to the upstream side of the first filter 22 through the return line 25, and the electromagnetic valve 26 on the discharge side to the river is closed. In addition, when the differential pressure measuring unit 24 measures the differential pressure exceeding the second set value, it indicates that the second filter 23 should be washed, so the control unit determines that the discharge to the river or the like is impossible. Similarly, the electromagnetic valve 27 is opened, and the electromagnetic valve 26 on the discharge side to the river or the like is closed.

  Here, even when the differential pressure exceeding the second set value is measured, the reason for prohibiting the discharge to the river or the like is that when the mud deposited on the inner surface of the second filter 23 is sucked by the suction nozzle 33, The first particle layer 40 and the second particle layer 41 formed in the part are also removed, and treated water containing high-concentration SS flows through the second filter 23 in the part, and as a result, the environmental reference value is set. Because it will not satisfy. For this reason, the discharge | release to a river etc. is prohibited until the 1st particle layer 40 and the 2nd particle layer 41 after that are formed during washing | cleaning.

  FIG. 5 is a diagram showing another configuration example of the muddy water treatment system. In this embodiment, in addition to the configuration shown in FIG. 2, a concentration measuring means for measuring the concentration of suspended matter (SS) in the second treated water is provided. As the concentration measuring means, a turbidimeter 28 for measuring turbidity corresponding to the concentration can be used. Since the turbidimeter 28 is an example, other devices can be used.

  The turbid water treatment flow is the same as in the embodiment shown in FIG. 2, but the turbidity corresponding to the SS concentration in the second treated water that has flowed out through the second filter 23 is measured by the turbidimeter 28. The control means (not shown) receives the measurement result from the turbidimeter 28, determines whether the turbidity is equal to or less than a threshold value, that is, a turbidity value corresponding to the environmental reference value (25 ppm in the river), and the differential pressure is the first. If it is greater than the set value and less than or equal to the second set value and the turbidity is less than or equal to the threshold value, the solenoid valves 26 and 27 are instructed, the solenoid valve 26 on the discharge side to the river etc. is opened, The solenoid valve 27 is closed.

  On the other hand, when the differential pressure is less than the first set value, the differential pressure exceeds the second set value, or the turbidity exceeds the threshold value, the control means instructs the electromagnetic valves 26 and 27 to turn the electromagnetic valve 27 on. Open and close the solenoid valve 26 to stop the discharge.

  In this way, by measuring turbidity using the turbidimeter 28 and judging from the measured turbidity, the environmental standard value can be more reliably observed, and the influence on the river environment and the like can be reduced. be able to.

  Further, the muddy water treatment system of the present invention includes the first filter 22, the second filter 23, the differential pressure measuring means 24 shown in FIG. 2, the electromagnetic valves 26 and 27 as switching means, and the turbidimeter 28 shown in FIG. In addition, a conveying means and a dehydrating device can be provided.

  A large number of particles collected by the first filter 22 and separated from the turbid water are collected to form mud, and the formed mud is transferred to a dehydrator by a conveying means 50 such as a conveyor as shown in FIG. Sent. As the conveying means 50, a screw feeder or the like can be used.

  The mud transported by the transport means 50 contains a lot of moisture, and its water content is high to be reused for land reclamation or ground improvement. Therefore, the mud must be dewatered for reuse.

  An apparatus for dehydration includes a dehydration apparatus. As one embodiment, the dehydration apparatus includes a dehydration container 51, a compressed gas supply means 52 such as an air compressor, and a gas suction means 53 such as a vacuum pump. be able to.

  The dehydrating container 51 is a hollow cylindrical container, and lids 51a and 51b that can be opened and closed are provided at both ends thereof. The dewatering container 51 is disposed so as to be inclined with respect to the horizontal direction, and the mud soil transported by the transport means 50 falls and is received into the dewatering container 51. At this time, the lid 51a is opened and the lid 51b is closed.

  When a predetermined amount of mud is placed, the lid 51a is closed, compressed gas is supplied by the compressed gas supply means 52, and the mud in the dehydration vessel 51 is blown. Thereby, since the inside of the dehydrating container 51 is pressurized, the dehydrating container 51 has a pressure resistance and a good sealing property. For this reason, the main body is a hollow cylindrical shape manufactured from a metal such as carbon steel or stainless steel having a predetermined thickness, and the lids 51a and 51b are also circular lids manufactured from the same metal, The lid is provided with a rubber packing or the like in order to improve the sealing performance.

  When the compressed gas supply means 52 is an air compressor, the compressed air becomes high temperature, and this high temperature compressed air is supplied into the dehydration container 51. Then, the moisture contained in the mud begins to evaporate due to the high-temperature air, and the moisture intervening between the particles is pushed out by increasing the internal pressure.

  The extruded water flows downward along the inclined bottom surface of the dehydrating container 51 and is appropriately extracted from a drain outlet 54 provided below the dehydrating container 51. The water extracted from the drain port 54 can be returned to the raw water tank.

  After stopping the air compressor, the vacuum pump is started, and the vacuum pump sucks air and sucks evaporated water. When the inside of the dehydration container 51 is depressurized, the water contained in the mud is vaporized to become water vapor, and the water vapor is sucked and removed, thereby reducing the volume. The volume of the mud inside is reduced by removing water.

  The mud thus dewatered naturally falls by opening the lid 51b of the inclined dewatering container 51, and since it does not contain chemicals, it can be reused for ground improvement and the like. In addition, since the volume and mass decrease, the dewatered mud becomes easy to convey.

  The compressed gas may be high-pressure nitrogen, high-pressure oxygen, high-pressure carbon dioxide gas, etc., but considering the safety in case of leakage, compressed air is preferable, and dry air is preferable in terms of removing moisture contained in the mud. . Note that when high-pressure nitrogen, high-pressure oxygen, high-pressure carbon dioxide, or the like is supplied, the gas can be supplied by a cylinder, a curdle, or the like.

  In FIG. 2, the muddy water treatment system includes a muddy water supply means 20, a first filter 22, a second filter 23, a differential pressure measurement means 24, a return line 25, and electromagnetic valves 26 and 27 as switching means. In the configuration provided, FIG. 5, the turbidimeter 28 is further provided. However, if turbid water is supplied at a predetermined pressure, the turbid water supply means 20 may not be provided.

  The muddy water treatment system can further include a transport unit 50 and a dehydrating device, and the dehydrating device can include a dehydrating container 51, a compressed gas supply unit 52, and a gas suction unit 53. However, since the water contained in the mud can be vaporized by the gas suction means 53 and sucked as water vapor, the dehydration apparatus may not include the compressed gas supply means 52.

  The dehydrating apparatus may be configured to include a filter cloth in the dehydrating container 51. For example, the dehydrating apparatus can include a bag 60 made of a filter cloth as shown in FIG. In this case, mud 61 is put in the bag 60, and a non-illustrated impermeable sheet is provided on the bag 60 with a gap so that water can be drained in the lower part, or the impermeable water. Covered with a bag made of a sheet made of the sheet, the mouth of the bag 60 is disposed toward the drain port 54, the lids 51a and 51b are closed, the compressed gas supply means 52 is activated to supply the compressed gas, and the inside of the dehydration container 51 Pressurize. The filter cloth absorbs moisture on the surface of the mud 61, and the impervious sheet is pushed inward by the surrounding gas when the inside of the dehydration container 51 is pressurized, and the bag is pushed by pushing it in. 60 is pushed inward, the mud 61 in the inside is further compressed, and the moisture contained in the mud 61 is squeezed out. The squeezed water flows to the drain outlet 54 and is appropriately discharged.

  Thereafter, the compressed gas supply means 52 is stopped, and the gas in the dehydration container 51 is sucked together with moisture present as vapor in the gas by the gas suction means 53. At this time, moisture absorbed by the filter cloth is also absorbed. When the inside of the dehydration vessel 51 is depressurized, moisture is removed in this way, and the volume can be reduced accordingly, so that the volume of the mud 61 inside is also reduced.

  In the above description, the mud is placed in the bag 60 and compressed and depressurized for dehydration. However, the mud 61 may be simply covered with a filter cloth and an impermeable sheet. In this case, the filter cloth absorbs moisture on the surface of the mud 61 and pressurizes the inside of the dehydration container 51, whereby the impermeable sheet is pushed inward, and the filter cloth is brought inward by being pushed in. The mud 61 in the mud 61 can be further compressed by compressing the mud 61 inside.

  In evaporative drying using a vacuum pump, the vacuum pump used has a negative pressure using oil viscosity. In this case, when vaporizing, water vapor is mixed with the oil, and the vacuum pump generates cavitation, which causes a failure. For this reason, dry freezing is generally employed in which a sample is frozen and solidified, and then directly vaporized and dried. However, since freezing takes cost and time, this method is currently limited to foods and the like. Moreover, although the method of drying at normal temperature by vacuum kettle drying is also known, in this case, it takes one and a half days to dry. Furthermore, in the method of performing steam drying using a vacuum kettle, there is a problem that condensation occurs when there are many samples with respect to the volume of the kettle.

  For this reason, the vacuum pump can be changed from an oil type to a water-sealed Elmo type pump as shown in FIG. The Elmo pump is a pump that has a caging 70 in a circular shape, rotates an impeller 71 in a casing 70 filled with water, causes a pressure change between the water surface and the rotor, and mainly sucks gas. is there. Since this pump can suck water vapor, by applying it to a dehydrator, it is not necessary to freeze in order to vaporize by sublimation like dry freezing, and cost reduction and time can be reduced.

  In order to prevent premature drying and condensation, the mud in the dehydration vessel 51 can be heated. Since there is no substance that conducts heat in a vacuum state, as shown in FIG. 9, heating means 80 for heating using electromagnetic waves or far infrared rays by a magnetron can be provided in the dehydrating container 51. Further, instead of the heating means 80 described above, a heat transfer heater is provided in the dehydration container 51, or a jet heater is provided outside the dehydration container 51, and hot air from the jet heater is supplied into the dehydration container 51, so that the dehydration container 51 It is also possible to preheat the interior of the interior 51 to a predetermined temperature and then perform suction with a vacuum pump as the gas suction means 53.

  When vacuum vaporization is performed by a vacuum pump and water vapor is sucked, water vapor is generated from the mud 61. However, since the dehydration vessel 51 is sealed, if the mud 61 contains a lot of water, Condensation often occurs and water accumulates. For this reason, compressed gas is injected into the dehydration container 51 by the compressed gas supply means 52 described above, and the injection of the compressed gas and the suction by the gas suction means 53 are repeated to remove the water vapor present in the dehydration container 51. be able to. The dehydrating container 51 uses the gas suction means 53, or the gas suction means 53 and the heating means 80 or the heater or the compressed gas supply means 52 in combination, and further the gas suction means 53 and the heating means 80 or the heater. 7 and compressed gas supply means 52 can be used together to properly remove moisture and dry the mud, it is not necessary to incline as shown in FIG. 7, and dehydration as shown in FIG. It is also possible to install the container 51 with its longitudinal direction horizontal.

  So far, dehydration using a dehydrator has been explained, but in order to dehydrate mud, in addition to the dehydrator described above, it is also possible to use bagging dehydration, sun drying, etc. It can also be used in combination. Bagging dehydration is a method of performing dehydration by filling mud soil in a bag having water permeability and stacking the bags. The mud underneath is crushed by the bagged mud placed on the top, and the water contained in the mud is discharged through the bag and dehydrated. In addition, as a material of the bag used for bagging, a resin material such as polyester can be used. Sun drying is a method in which mud is spread and placed in a place where sunlight is irradiated, and the mud is warmed and moisture is evaporated to perform dehydration.

  Next, a turbid water treatment method using this turbid water treatment system will be briefly described. First, particles contained in the supplied turbid water are separated by a first filter 22 having a plurality of holes. Since the particles do not pass through the plurality of holes, the particles are trapped on the surface of the first filter 22, and only those having a small particle diameter pass as the first treated water together with water. Next, the first treated water is received into the container 30 as shown in FIG. 3 and sent to the inside of the hollow cylindrical second filter 23, and the particles are captured by the inner surface of the second filter 23. Only the water that has passed through 23 is discharged as the second treated water.

  In the second filter 23, the differential pressure is measured by the differential pressure measuring means 24 from the water pressure of the first treated water sent to the inside of the second filter 23 and the water pressure of the second treated water that has passed through the second filter 23. Is done. Then, it is determined whether the differential pressure is not less than the first set value and not more than the second set value. When the measured turbidity is greater than or equal to the first set value and less than or equal to the second set value, the second treated water is discharged into a river or the like by the electromagnetic valves 26 and 27 serving as switching means. The delivery direction is switched to the return line 25 which switches the opening and closing of the valves 26 and 27 and returns to the upstream side of the first filter 22. Thereby, when SS density | concentration is high, it can prevent that it discharges | emits to a river etc. and can prevent having an influence on natural environment. The treated water having a high SS concentration is supplied to the upstream side of the first filter 22 through the return line 25 and is introduced into the first filter 22 together with the muddy water supplied by the muddy water supply means 20.

  The mud separated by the first filter 22 is placed in a dehydration container 51 shown in FIGS. 6 and 7, and sealed with a lid, and then compressed gas is supplied into the dehydration container 51, and moisture is introduced into the compressed gas. While evaporating, the water intervening between the soil particles in the mud is pushed out and dehydrated, and then the gas containing the evaporated water is sucked to remove the water contained in the mud and reduce the volume of the mud. Thereby, it becomes a dewatered mud with a low water content and a reduced volume, does not contain chemicals, and can have a corn index of 200 kN or more, so this dewatered mud can be reused in the field.

  Further, the mud captured and separated by the first filter 22 can be transported by the transport means 50. The water contained in the conveyed mud can be removed by a dehydrating device that includes the dewatering container 51 that receives the mud and sucks the gas in the dewatering container 51.

  As described above, in the present invention, muddy water can be treated only by using two filters, a differential pressure measuring unit, and a switching unit, so that the space of the apparatus can be saved and can be provided at low cost. . In addition, by using a natural palm fiber filter as the first filter, it can be effectively used as a greening base material or the like in the field without being discarded when the replacement time is reached. Moreover, since the recovered mud does not use chemicals, it can be effectively used in the field after dehydration.

  In the present invention, in addition to the embodiment described above, as shown in FIG. 10, it is possible to adopt a configuration in which the differential pressure measuring means 24 is not used. In this case, the control means determines the turbidity measured by the turbidimeter 28 and controls the electromagnetic valves 26 and 27. That is, the turbidity value corresponding to the environmental standard value (25 ppm for rivers) is set as a threshold value, and if it is equal to or lower than the threshold value, the electromagnetic valve 26 is opened and the electromagnetic valve 27 is closed and discharged to a river or the like. On the other hand, when the threshold value is exceeded, the electromagnetic valve 27 is opened, the electromagnetic valve 26 is closed, the discharge to the river or the like is stopped, and everything is returned.

  At this time, the second separation means includes a hollow cylindrical container 30 having a receiving nozzle 31 for receiving the first treated water as shown in FIG. 3 and a discharge nozzle 32 for discharging the second treated water, When it is configured to include the cylindrical second filter 23 disposed inside, the particles contained in the first treated water are captured on the inner surface of the second filter 23 and configured from the particles. The first particle layer is formed, and particles having a particle size smaller than the particles constituting the first particle layer are captured to form the second particle layer composed of the particles. That is, a filter structure as shown in FIG. 4 is formed.

  In the second separation means, the particles contained in the first treated water are captured and separated using the first particle layer and the second particle layer thus formed, and the second filter 23. Thereby, even if it does not use a filter with a fine mesh size, fine particles can be captured by the particle layer formed by the captured particles, so SS can be removed more effectively. It can be provided at low cost.

  The muddy water treatment system and muddy water treatment method of the present invention have been described in detail with reference to the embodiments shown in the drawings, but the present invention is not limited to the above-described embodiments, and other embodiments are described. It can be modified within the range that can be conceived by those skilled in the art, such as addition, change, deletion, etc., and any embodiment is included in the scope of the present invention as long as the operation and effect of the present invention are exhibited. is there. Therefore, the dehydrating apparatus is not limited to the one having the above-described configuration, and it is possible to dehydrate using a filter press. Moreover, since the soil taken out from the dehydrator is dehydrated, it can be used as it is, but it can be reused for ground improvement by further drying the sun and improving the corn index. .

DESCRIPTION OF SYMBOLS 10 ... Sand settling tank, 11 ... Turbid water treatment apparatus, 12 ... Coagulation sedimentation tank, 13 ... Discharge water tank, 14 ... Sludge storage tank, 15 ... Sludge dewatering apparatus, 20 ... Turbid water supply means, 21 ... Piping, 22 ... 1st filter, 23 ... 2nd filter, 24 ... Differential pressure measuring means, 25 ... Return line, 26, 27 ... Solenoid valve, 28 ... Turbidimeter, 30 ... Container, 31 ... Receiving nozzle, 32 ... Discharging nozzle, 33 ... Suction nozzle, 34 ... cylinder, 35 ... chamber, 36 ... mud discharge valve, 37 ... movable means, 40 ... first particle layer, 41 ... second particle layer, 42 ... third particle layer, 50 ... transport means, 51 ... dehydration container 51a, 51b ... lid, 52 ... compressed gas supply means, 53 ... gas suction means, 54 ... drainage port, 60 ... bag, 61 ... mud, 70 ... casing, 71 ... impeller, 80 ... heating means

Claims (17)

A muddy water treatment system for treating muddy water,
First separation means for capturing a part of particles contained in the muddy water and sending out first treated water from which the mud made of the captured particles has been separated;
Second separation means for capturing the particles remaining in the first treated water and discharging the second treated water from which the remaining particles have been separated;
Differential pressure measuring means for measuring the differential pressure of the first treated water and the second treated water;
When the measured differential pressure is less than the first set value or exceeds the second set value higher than the first set value, the discharge of the second treated water is stopped and before the first separation means A muddy water treatment system, comprising: a switching unit that switches a delivery direction of the second treated water to a return line that returns to the flow side.   The muddy water treatment system according to claim 1, wherein the first separation unit is a palm fiber filter. The second separation means includes a hollow cylindrical container having a receiving nozzle that receives the first treated water and a discharge nozzle that discharges the second treated water, and a cylindrical filter disposed inside the container. Including
A first particle layer composed of particles contained in the captured first treated water on the inner surface of the filter, and a second particle composed of particles having a particle diameter smaller than the particles constituting the first particle layer. A particle layer is formed, and particles contained in the first treated water are captured and separated using the first particle layer and the second particle layer together with the filter. The muddy water treatment system described.   The muddy water treatment system according to claim 3, wherein the second separation unit further includes a cleaning unit for sucking and removing the mud composed of the particles deposited on the inner surface of the filter.   The cleaning means includes a suction nozzle disposed adjacent to the mud deposited on the inner surface of the filter, and is disposed continuously to the suction nozzle and rotatably on a central axis of the container. A cylinder that is movable in a direction, a chamber that is continuous with the cylinder and has a diameter that is larger than the diameter of the cylinder, and is continuous with the chamber for opening the inside of the chamber to the atmosphere. The muddy water treatment system of Claim 4 provided with a mud discharge valve and the movable means to rotate the said cylinder and to move to the longitudinal direction of the said container. A concentration measuring means for measuring a suspended matter concentration in the second treated water discharged from the second separating means;
When the differential pressure measured by the differential pressure measuring unit is less than the first set value, or when the differential pressure exceeds the second set value, or the suspended matter measured by the concentration measuring unit The muddy water treatment system according to any one of claims 1 to 5, wherein when the concentration exceeds a threshold value, the delivery direction of the second treated water is switched to the return line that returns to the upstream side of the first separation means. .   The turbid water treatment system according to any one of claims 1 to 6, further comprising a dewatering device for dewatering the mud separated by the first separation means.   The muddy water treatment system according to claim 7, wherein the dewatering device includes a dewatering container that receives the mud and removes moisture contained in the mud by sucking a gas in the dewatering container.   The dehydration apparatus includes a gas suction unit that sucks the gas in the dehydration vessel, and further heats the compressed gas supply unit that supplies the compressed gas into the dehydration vessel or the mud contained in the dehydration vessel. The muddy water treatment system according to claim 8, comprising means or both. A muddy water treatment system for treating muddy water,
First separation means for capturing a part of particles contained in the muddy water and sending out first treated water from which the mud made of the captured particles has been separated;
Second separation means for capturing the particles remaining in the first treated water and discharging the second treated water from which the remaining particles have been separated;
Concentration measuring means for measuring the concentration of suspended matter in the second treated water;
Switching means for stopping the discharge of the second treated water and switching the delivery direction of the second treated water to a return line that returns to the upstream side of the first separation means when the measured concentration exceeds a threshold value; Including
The second separation means includes a hollow cylindrical container having a receiving nozzle that receives the first treated water and a discharge nozzle that discharges the second treated water, and a cylindrical filter disposed inside the container. Including
A first particle layer composed of particles contained in the captured first treated water on the inner surface of the filter, and a second particle composed of particles having a particle diameter smaller than the particles constituting the first particle layer. A muddy water treatment system, wherein a particle layer is formed, and particles contained in the first treated water are captured and separated using the first particle layer and the second particle layer together with the filter. A muddy water treatment method for treating muddy water,
A step of capturing a part of particles contained in the muddy water by a first separation means having a plurality of holes, and sending the first treated water from which the mud made of the captured particles has been separated to the second separation means; ,
Capturing the particles remaining in the first treated water with the second separation means having a plurality of holes, and discharging the second treated water from which the remaining particles are separated; and
Measuring a differential pressure of the first treated water and the second treated water;
When the measured differential pressure is less than the first set value or exceeds the second set value higher than the first set value, the discharge of the second treated water is stopped and before the first separation means A muddy water treatment method including a step of switching the delivery direction of the second treated water to a return line returning to the flow side.   The muddy water treatment method according to claim 11, wherein the first separation unit is a palm fiber filter. The second separation means includes a hollow cylindrical container having a receiving nozzle that receives the first treated water and a discharge nozzle that discharges the second treated water, and a cylindrical filter disposed inside the container. Including
The method includes a step of forming a first particle layer composed of particles contained in the captured first treated water on the inner surface of the filter, and the first particle layer is formed on the first particle layer. Including a step of forming a second particle layer composed of particles having a particle size smaller than that of the constituting particles, and using the first particle layer and the second particle layer together with the filter, and included in the first treated water The turbid water treatment method according to claim 11 or 12, wherein particles to be collected are captured and separated.   The muddy water treatment method according to claim 13, further comprising a step of sucking and removing the mud composed of the particles deposited on the inner surface of the filter. Further comprising the step of measuring the suspended matter concentration in the second treated water discharged from the second separation means,
In the switching step, when the differential pressure measured in the step of measuring the differential pressure is less than the first set value, or exceeds the second set value, or in the step of measuring the suspended matter concentration When the measured suspended solid concentration exceeds a threshold value, the delivery direction of the second treated water is switched to the return line returned to the upstream side of the first separation means. The turbid water treatment method as described in 2. Transporting the mud captured and separated by the first separating means by a conveying means;
The muddy water according to any one of claims 11 to 15, further comprising a step of removing water contained in the mud by a dehydrating device that includes a dewatering container that receives the mud and sucks a gas in the dewatering container. Processing method. A muddy water treatment method for treating muddy water,
A step of capturing a part of particles contained in the muddy water by a first separation means having a plurality of holes, and sending the first treated water from which the mud made of the captured particles has been separated to the second separation means; ,
Capturing the particles remaining in the first treated water with the second separation means having a plurality of holes, and discharging the second treated water from which the remaining particles are separated; and
Measuring the concentration of suspended matter in the second treated water;
When the measured concentration exceeds a threshold value, stopping the discharge of the second treated water and switching the delivery direction of the second treated water to a return line that returns to the upstream side of the first separation means; Including
The second separation means includes a hollow cylindrical container having a receiving nozzle that receives the first treated water and a discharge nozzle that discharges the second treated water, and a cylindrical filter disposed inside the container. And includes
The step of discharging the second treated water includes forming a first particle layer composed of particles contained in the captured first treated water on the inner surface of the filter, and on the first particle layer. Using the first particle layer and the second particle layer together with the filter, the step of forming a second particle layer composed of particles having a particle size smaller than the particles constituting the first particle layer, A method for treating turbid water, comprising a step of capturing and separating particles contained in one treated water.