JP2009000638A - Method for purifying muddy water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for purifying muddy water such as water overflowed from a river and muddy water disposed over a riverbed or a seabed each containing hardly sedimentable particles as its suspended component, which method does not swirl up sediment settled if the flow rate of inflowing muddy water in a settling tank even is increased as in an event of torrential rain or the like. <P>SOLUTION: The method for purifying muddy water by introducing muddy water such as water overflowed from a river and muddy water disposed over a riverbed or a seabed each containing hardly sedimentable particles as its suspended component into a settling tank, causing easily sedimentable particles to settle therein, and subsequently purifying the clear water layer in the settling tank which water layer contains hardly sedimentable particles, is practiced using a settling tank characterized by comprising a reservoir space wherein a plurality of packing members each equipped with tilting plate members of a roughly square horizontal image as viewed from thereabove tilting in one direction are stacked in the vertical direction in a manner forming gaps between the tilting plate members so as to allow the easily sedimentable particles to flow down on the tilting faces of the tilting plate members toward the bottom of the reservoir space. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for purifying muddy water containing hardly settled particles that are hard to settle, such as red clay.

In general, when it rains in a river basin, rainwater that does not penetrate the ground flows down the sewer or the ground surface and flows into the river. In particular, in sewerage sewer areas where general household wastewater and rainwater drainage are separated, it is common for rainwater sewers to be discharged directly into rivers without being connected to a sewage treatment center. For this reason, all rainwater that does not permeate the ground flows into the river in areas where sewerage is not yet developed or in sewerage sewerage areas.
Even in a combined sewer area where general drainage and rainwater drainage are connected, in the case of heavy rain of 100 mm or more (30 mm or more in some cases) per hour, the drainage capacity of the sewer will be exceeded, and rainwater May stay. Therefore, the ground surface stagnant rainwater flows down the ground surface, and as a result, most of the ground surface stagnant rainwater flows into the river.

In this way, rainwater often flows into rivers, but when this rainwater flows, earth and sand from nearby fields, construction areas, grounds, etc. become muddy water mixed in rainwater and flow into the river. May contaminate rivers.
In general, Japanese rivers have a long total distance, and sediment components tend to flow into the upstream, where urbanization has not progressed. The main problem is that when the rain is over, the pollution is eliminated and the soil hardly flows into the ocean. In addition, even if earth and sand flows into the ocean, the amount is small, so it will not spread to the ocean and affect the ecosystem.

  However, among the rivers in Japan, remote islands and rivers with a short distance from the mountains to the sea area are short and steep, so most of the sediment flowing into the river does not accumulate in the middle of the river, There are areas that flow into the ocean. In remote islands in particular, there are many agricultural settlements and fields in the basin, and the amount of sediment that flows out often increases.

Further, in the remote islands in the south, there are cases where the periphery of the island is covered with a coral reef, and in this case, the accumulated sediment cannot go out from the coral reef zone, and the amount of accumulation is often increased.
For this reason, if the vicinity of the river mouth is a tourist area, such as when the coral died or the white beach is replaced with earth, tourism resources may be destroyed and become a serious problem.

For example, in the case of a soil with a fine particle size such as red soil on the main island of Okinawa, it is eroded by rainfall and often flows into a sand basin at a concentration of 2000 ppm or more, but a component with a particle size of 20 μm or less occupies 50% or more. Because of its fine particle size, natural sedimentation does not sufficiently settle for several hours, and it cannot stop the outflow to rivers and oceans.
In addition, the red soil called Kunigami Marge, which is often found in the northern part of the main island of Okinawa, is strongly acidic, so when the red soil enters the seawater, the pH of the seawater is lowered, the sea becomes acidic and aluminum ions are leached, which causes coral to dissolve. There is a risk that sea creatures such as will be sustained.

  As a method for purifying such muddy water, first, there is a method in which muddy water is introduced into a sedimentation tank, and sedimentary particles such as pebbles, sand, and clots in muddy water are allowed to settle, and the supernatant water is filtered by membrane filtration or the like. It has already been proposed (see Patent Document 1).

However, in the case of the turbid water purification method as described above, there is no problem when treating the turbid water generated at the construction site, etc., but a large amount of turbid water flows into the sedimentation tank at a high inflow rate due to heavy rain. Under such conditions, there are the following problems.
In other words, in a sedimentation tank such as a normal sand basin, when the inflow speed increases, for example, in the case of heavy rain, sediments such as easily settled particles that have accumulated at the bottom of the sedimentation tank are wound up in the sedimentation tank. There is a problem that rough sand or a lump of soil flows into the filtration device and damages the filtration device.

JP 2001-104953 A

  In view of the above circumstances, the present invention does not roll up sediment that has settled first, even if the inflow speed of turbid water flowing into the sedimentation tank becomes faster as in heavy rain, river overflow water, river sediment It is an object of the present invention to provide a method for purifying turbid water containing hardly settled particles of either turbid water or marine sediment turbid water as a suspended component.

  In order to achieve the above object, the method for purifying muddy water according to claim 1 of the present invention (hereinafter referred to as “the method for purifying muddy water according to claim 1”) includes river overflow water, river sediment turbid water and marine sediment muddy water. After introducing turbid water containing any of the difficult-to-settling particles in the suspension component into the sedimentation tank and precipitating the easy-settling particles in the sedimentation tank, the supernatant water containing the hardly-settable particles in the sedimentation tank is used. A method for purifying muddy water for purification treatment, wherein the settling tank has a water storage space, and a filling member having a substantially square plate shape and having an inclined plate portion inclined to one side includes an inclined plate portion and an inclined plate. In the water storage space in a state where a plurality of layers are stacked in the vertical direction so that easily settleable particles flow down toward the bottom of the water storage space along the inclined surface of the inclined plate portion. It is characterized by being filled.

  The method for purifying muddy water according to claim 2 of the present invention (hereinafter referred to as "the method for purifying muddy water according to claim 2") is the muddy water purifying method according to claim 1, wherein a recess is provided at the bottom of the water storage space. A filling member is assembled in the water storage space so as to form a path that guides easily settleable particles in muddy water flowing into the settling tank to the recess by the inclination of the inclined plate portion.

  The method for purifying muddy water according to claim 3 of the present invention (hereinafter referred to as “the method for purifying muddy water according to claim 3”) is the method of purifying muddy water according to claim 1 or claim 2, wherein a flocculant is added to the supernatant water. It is characterized by comprising a step of adding and coagulating and suspending suspended components, and solid-liquid separation of the resulting precipitate with a dehydration filtration device.

  The method for purifying muddy water according to claim 4 of the present invention (hereinafter referred to as “the method for purifying muddy water according to claim 4”) is the method for purifying muddy water according to claim 1 or claim 2. A step of separating into filtered water and a suspension containing high concentration hardly sedimentable particles by adding a flocculant to the suspension containing high concentration hardly settleable particles, and aggregating and precipitating And a step of subjecting the product to dehydration filtration and solid-liquid separation with a second filtration device.

In the present invention, the filling member is not particularly limited, but is preferably formed of a lightweight material such as a synthetic resin in consideration of workability.
The flocculant used in the present invention is not particularly limited, and a known flocculant can be used. However, -O-CO- in a molecule that aggregates with a polyvalent metal ion and is easily dispersible in water. It is preferable to use a viscous polymer material having a structural portion as a flocculant.
That is, the cross-linking reaction between the minus charge of the —O—CO— structure portion and the plus charge of the polyvalent metal salt occurs rapidly. Therefore, adjacent viscous polymers can be cross-linked to form an aggregate in a short time.

  The viscous polymer material is not particularly limited, and examples thereof include viscous polysaccharides having a —O—CO— structure moiety in molecules derived from natural products such as alginate, pectin, glucomannan, and fucoidan. Natural product dry fine powders containing alginates such as hinoki, mekabu, konjac and mozuku, pectin, glucomannan, fucoidan and the like may be used.

  In addition, as natural product dry fine powder, it is possible to use waste pulverized material because it can effectively use waste and prevent waste processing costs and air pollution related to waste processing. Good. In particular, it is also effective to use the waste material component in the production of natural viscous polysaccharide plant products in the area where solid-liquid separation of fine particle size soil contaminated water is desired. If it occurs, it is not particularly limited.

  When natural product dry fine powder is used as the aggregating agent, the particle size of the natural product dry fine powder is not particularly limited, but is preferably about 1 to 100 μm on average. That is, when the particle size of the natural product dry fine powder is too fine, it absorbs moisture in the air and forms a viscous paste, which is difficult to handle and has poor dispersibility in the solution. On the other hand, if the particle diameter is too coarse, the elution of the viscous component into the solution is not sufficient, and there is a possibility that sufficient aggregation reaction will not occur even if polyvalent metal ions are added.

In the case of a natural product dry fine powder, the natural product dry fine powder is charged and swollen, and the hardly settleable particles are adsorbed on the natural product dry fine powder swollen by uniform stirring to settle together with the natural product dry fine powder. It can also be made. That is, in this way, with the addition of a few kinds of materials, in the state of being entangled with the fibrous material of the viscous polysaccharide extending from the natural product dry fine powder around the natural product dry fine powder swollen the hardly sedimentable particles. The hardly settleable fine particles are adsorbed (trapped) and settled together with the natural product dry fine powder in a short time, and the suspended water is purified in a short time.
In addition, because natural product dry fine powder is used, even if the agglomerate is treated as it is, the natural product dry fine powder and the dissolved viscous polysaccharide are biodegraded in the soil, causing pollution and the like. There is no.

As described above, in the method of adsorbing the hardly sedimentable particles to the natural product dry fine powder and precipitating together with the natural product dry fine powder, the natural product dry fine powder is more reliably used as the natural product dry fine powder. It is preferable to use one having an average particle diameter of 100 to 3000 μm because it can be adsorbed and settled on the dry fine powder.
In the method of adsorbing the hardly sedimentable particles to the natural product dry fine powder and precipitating with the natural product dry fine powder, in order to more reliably adsorb the hardly settled fine particles to the natural product dry fine powder, It is preferable that the concentration of hardly settled fine particles to be treated is 10,000 ppm or less and the concentration of the natural product dry fine powder is 5 ppm or more.

As a method of aggregating the suspended components in the suspension water with the viscous polymer material, first, after dissolving the viscous polymer material in the suspension water, a polyvalent metal salt granular material composed of polyvalent metal ions or its subsaturation It is preferable that the aqueous solution is poured into the suspension water at once and rapidly stirred to dissolve the polyvalent metal ions quickly.
As the polyvalent metal salt, calcium salt and magnesium salt are preferable, and granular calcium chloride and magnesium chloride are particularly preferable.

  As described above, by adding the polyvalent metal salt granular material or its semi-saturated aqueous solution and rapidly stirring and mixing, the addition of a small number of materials causes a large agglomeration of less sedimentable particles in suspension water with low viscosity. A lump can be formed, the agglomerate can settle in a short time, and the suspended water can be purified in a short time. That is, when a polyvalent metal salt powder is charged at once into a mixed liquid in which a viscous polymer material is uniformly dispersed, gelation of high polymerization proceeds at a stretch by the action of polyvalent metal ions, and hardly settled particles A large agglomerate is formed in a short time. On the other hand, when the polyvalent metal salt is first mixed with the suspension water and then the viscous polymer material is added, the aggregation with the polyvalent metal occurs as soon as the viscous polymer material is added, and the viscous polymer material gel Only bead is produced and it serves only to fix water as a swollen gel. In addition, when the polyvalent metal salt is added in the form of an aqueous solution, only small aggregates can be obtained.

Rapid stirring means stirring so that the polyvalent metal salt can be uniformly dissolved in the entire suspended water within 30 seconds after the polyvalent metal salt powder or its semi-saturated aqueous solution is charged at once.
In addition, it is preferable that the polyvalent metal salt particles or the semi-saturated aqueous solution thereof is added all at once to the entire surface of the treatment tank of the suspended water.
The semi-saturated aqueous solution is a high concentration aqueous solution having a saturation concentration of 50% or more.

  The stirring method is not particularly limited, but in addition to stirring using a normal stirring blade, a part of the flow path of the pipe is blocked inside the pipe that transports the mixed liquid obtained by mixing the viscous polymer material with the suspension water. In addition, a plurality of baffle plates are intermittently provided in the pipe axis direction of the pipe, and the long axis of each baffle plate is arranged with an angle shifted by 90 degrees with respect to the long axis of the adjacent baffle plate in the pipe axis direction of the pipe. In addition, there is a method of bringing the mixed solution into a stirring state in the pipe by causing the mixed solution to hit the baffle plate.

  The method of intermittently providing the baffle plate in the pipe has a simple structure and can reduce the equipment cost. In addition, since the adjacent baffle plates are arranged so as to be displaced by 90 degrees, the water flow in the pipe is repeatedly divided into left and right by the baffle plates to cause turbulent flow, and can be efficiently and rapidly stirred. That is, in the division of the water flow by the baffle plate, the water flow circulates on the back side of the plate and generates turbulent flow.

Furthermore, it is preferable that the baffle plate has a size of 20% to 70% of the inner cross-sectional area of the pipe and is arranged with an interval of 0.5 to 2 times the inner diameter of the pipe.
That is, depending on the flow velocity and viscosity of the processing liquid flowing in the pipe, if the size of the baffle is less than 20% of the inner cross-sectional area of the pipe, the division efficiency is small and the effect is difficult to be exhibited, and if it exceeds 70% There is a possibility that the resistance becomes too large and mixing and stirring becomes insufficient. In addition, depending on the flow rate and viscosity of the processing liquid flowing in the pipe, if the interval is shorter than 0.5 times, only the resistance due to the baffle plate is generated, and the mixing is not effective. After that, it will hit the next baffle plate and there is a risk that efficient stirring will not be possible

  As the polyvalent metal salt, those comprising a calcium salt or a magnesium salt are preferable because large aggregates can be obtained more quickly, and granular calcium chloride or magnesium chloride is particularly preferable. In addition, the components in the liquid obtained by solid-liquid separation of the agglomerates are residual calcium ions, sodium ions substituted with calcium ions, and the like, and chloride ions, so there is no impact on the ecosystem.

  The agglomerates produced by agglomeration by the aggregating agent are not particularly limited, but the treated water containing the agglomerates is separated from the water by a dehydrator or a cyclone separator, and then subjected to landfill treatment as it is, or bonded by heat drying. After mixing with the agent, it can be molded into a molded product, or sintered as it is to be used as a soil improvement material, or used as a wave-dissipating block or paving tile.

  In the present invention, the sedimentation tank may be open at the top or embedded in the basement, but it is possible to prevent the introduction of foreign matter, accidental fall of humans and animals, the generation of malodor due to the generation of algae, In addition, since the above-ground part can be effectively used, the underground type is preferable.

  In addition, from the rivers and oceans, there is a risk that foreign substances that may interfere with the purification process, including synthetic resin bags, may flow into the sedimentation tank. It is preferable to provide a coarse screen to prevent such foreign matter from flowing into the sedimentation tank.

  Moreover, it is preferable to provide an overflow part in the upper part of a sedimentation tank.

  In the method for purifying muddy water according to claim 4, the first filtration device is not particularly limited as long as it can remove a suspended component having a relatively small particle diameter. For example, a microfiltration membrane (MF), an ultrafiltration membrane (UF) ), A filtration device using a reverse osmosis membrane (RO) or the like as a filter medium, and it is a suspended component having a particle size of 0.1 μm or more that affects the cocoon and other biological environments. It is preferable to use a microfiltration membrane from the viewpoint of ease of handling. The shape of the microfiltration membrane may be a hollow fiber or a membrane. The hollow fiber type is preferable from the viewpoint of space saving. The hollow fiber may be filtered from the inside of the hollow fiber to the outside using a pressure pump, or may be sucked and sucked from the outside to the internal gap, but it is preferable to filter by suction from the viewpoint of energy efficiency. . Further, when it is desired to remove salt, a reverse osmosis membrane may be used.

In the method for purifying muddy water according to claim 4, as a method for obtaining a suspension containing highly-concentrated hardly settled particles, the filter medium is back-washed at regular time intervals or when the filtration pressure exceeds a certain level, Return to the settling tank, increase the concentration of difficult-to-set particles in the settling tank, or backwash and filter for a very short time so that the clogging of the filter medium can be eliminated at regular intervals or when the filtration pressure exceeds a certain level. There is a method of obtaining a suspension containing highly-concentrated hardly settleable particles in the apparatus.
In addition, backwashing is performed by flowing fresh water in the direction opposite to the filtration direction. Moreover, when removing the suspended component which attracted | sucked and isolate | separated inside from the hollow fiber exterior, you may wash by performing bubbling on the filter outer surface. Foam may be passed through a hole such as a woodstone, or may be generated by refining air using a Venturi tube, or by opening a swirling flow method or a pressure-dissolved one, or using ultrasonic cavitation.

The filtered water separated by the first filtering device is mainly discharged into rivers and oceans, but may be sprayed onto fields and roads as necessary.
Moreover, although the obtained suspension containing a high concentration suspension component may be recovered as it is, the water content is high and the transportation efficiency for disposal may be poor and the cost may be high. Be careful when spraying around the area as it may dry out and scatter and accumulate in rivers and oceans again. In addition, since dust damage is also a concern, it is preferable to take measures to prevent scattering when spraying.

  Moreover, when marine sediment sludge is contained in muddy water, since salt content is also included, it is preferable that a pipe and filtration equipment are comprised with plastics. When using a steel pipe, it is preferable to use a lining steel pipe whose inside is covered with plastic or the like.

  Although it does not specifically limit as a 2nd filtration apparatus, For example, any of a filter press, a screw press, a moisture evaporation system, a filter filtration system, and a membrane filtration system may be sufficient, but a circulation type filter cloth system is a space-saving surface. To preferred. The filter cloth or the like is preferably always or sequentially washed with clean water, but is not particularly limited. Further, the washing may be performed in the direction opposite to the filtration direction, or water may be sprayed directly on the filtration surface. If the dirt is severe, an acid such as hypochlorous acid or an alkali such as caustic soda may be used.

  As described above, the method for purifying turbid water according to the present invention introduces turbid water containing suspended sediments of any one of river overflow water, river sediment turbid water and marine sediment turbid water into a sedimentation tank, A method for purifying muddy water in which a sedimentary liquid in a sedimentation tank is settled after the sedimentation of easily settleable particles in the tank, wherein the sedimentation tank has a water storage space, and is omitted in plan view. The water storage space in a state in which a filling member having a square plate shape and having an inclined plate portion inclined to one side is stacked in a plurality of stages in the vertical direction so as to form a gap between the inclined plate portion and the inclined plate portion. Therefore, even if a large amount of muddy water flows at a time due to heavy rain or the like, sediment such as easily settled particles collected at the bottom of the sedimentation tank is not rolled up.

  In addition, a recess is provided at the bottom of the water storage space, and a filling member is provided in the water storage space so as to form a path that guides easily settleable particles in muddy water flowing into the sedimentation tank to the recess by the inclination of the inclined plate portion. When assembled, sediments such as easily settled particles settled in the recesses. Therefore, dredging in the sedimentation tank can be easily performed by sucking up the sediment accumulated in the recess with a suction pump or the like.

  Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.

FIG. 1 shows an example of a system used in the method for purifying muddy water according to the present invention, and FIGS. 2 to 4 show a sedimentation tank portion used in this system.
As shown in FIG. 1, this processing system includes a filter-equipped 126, a sedimentation tank 100, a first filtration device 42, a suspension water treatment device 43, a pump 44 as a water drawing device, and a second filtration. The apparatus 45, the storage tank 46, and the track | truck 47 as a mounting base which has a rolling wheel are provided.

As shown in FIGS. 1 to 4, in this treatment system, the muddy water 48 flows into the sedimentation tank 100 through the introduction pipe 125, the filter-attached tub 126, and the introduction pipe 125 branched from the filter-attached tub 126. It has become.
The filter-equipped trough 126 is provided so as to remove large foreign substances such as a synthetic resin bag in the muddy water 48 before the muddy water 48 flows into the sedimentation tank 100 through the introduction pipe 125.

As shown in FIG. 2, the sedimentation tank 100 is formed by digging the ground surface 101 into a rectangular shape to form the excavation portion 102, and laying and solidifying a crushed stone or the like on the bottom surface of the excavation portion 102 to fix the foundation portion 103. In the formed water storage space 110, as shown in FIGS. 2 to 4, a large number of filling members 130, which will be described later, are horizontally arranged in portions other than the rectangular manholes 115, 116 described later, as described below. In addition, it is installed in a state of being connected in the vertical direction.
The bottom surface of the water storage space 110 is basically a flat surface, and a groove-shaped recess 111 that is stepped down from the flat surface at the center in the long side direction of the bottom surface covers the entire width of the bottom surface in the short direction. Is formed.

A waterproof sheet 112 is laid on the entire bottom surface of the water storage space 110 including the bottom surface of the recess 111. As the waterproof sheet 112, a synthetic rubber, a resin sheet or an asphalt sheet having a thickness of 1.5 mm or more is used. A lattice-shaped frame 114 is fitted into the recess 111, and the upper end surface of the frame 114 is substantially flush with the flat surface of the water storage space 110.
Note that a protective board 113 may be laid on the base portion 103 formed of cracked stone or the like, and the waterproof sheet 112 may be laid thereon. In addition, instead of the protective board 113 described above, a base sheet (not shown) such as a polyester-based non-woven sheet is laid under the waterproof sheet 112 as necessary, and the waterproof sheet 112 is removed from the cracked stone of the base portion 103. You may make it protect.

  Each filling member 130 is formed of a plastic such as polyethylene, polypropylene, vinyl chloride, or polyethylene terephthalate, or a waste plastic thereof, and as shown in detail in FIGS. The four columnar connecting portions 131 that support the vertical load of the member 140 and the horizontal load due to water pressure and secure a water passage in the water storage space 110, and are fixed to the four connecting portions 131 and 5 degrees with respect to the horizontal plane It is composed of an inclined plate portion 132 having a substantially square shape in plan view that is inclined at an angle of about, and is not particularly limited. For example, a shape that fits in a rectangular parallelepiped having a side of about 50 cm to 1 m and a height of about 10 to 15 cm. I am doing.

  The connecting portion 131 is formed of a thick plate material having a thickness of about 4 to 5 mm, is formed in a triangular pipe shape having a height of about 10 to 15 cm, and is formed below the upper pillar portion 131a having a large cross-section of the triangular pipe shape. Is formed with a triangular pipe-shaped lower column part 131b having a small cross section that fits inside the upper column part 131a. Therefore, the filling member 130 can be stacked at a small pitch, that is, the height of the connecting portion 131 by fitting the lower pillar portion 131b of the other filling member 130 into the upper pillar portion 131a of the filling member 130. . Through holes 131c and 131d are formed on the bottom and side surfaces of the triangular pipe-shaped connecting portion 131 so that water can enter from the lower through holes, and the internal air can escape from the side through holes. It can be done. In addition, although the corner part is notched, the lower pillar part 131b may be continuous. Further, it is preferable that the bottom surface in the connecting portion 131 is inclined in the direction of the through hole on the side surface in order to guide earth and sand to the inclined plate portion 132.

  The inclined plate portion 132 is a thick plate member having a thickness of about 4 to 5 mm, is formed in a substantially square shape with a side of about 50 cm to 1 m, for example, and guides for guiding inflowing water such as muddy water 48 flowing in a predetermined direction. Is configured.

The upper surface of the inclined plate portion 132 is flat and becomes lower toward the tip direction of the inclined direction S.
If the inclination angle is too gentle, easy-settling particles such as sand contained in the inflowing water do not flow with the inflowing water but stay on the inclined plate portion 132, and therefore an inclination angle of about 5 degrees is preferable.

  On the lower surface of the inclined plate portion 132, lattice-like reinforcing ribs 133 are formed for reinforcement so as to stand vertically and horizontally integrally at a predetermined interval. The reinforcing rib 133 is formed so that the vertical width of the central portion of the inclined plate portion 132 is large and the vertical width gradually decreases toward the periphery. With this configuration, even if a load is applied to the upper surface of the inclined plate portion 132, the deformation of the inclined plate portion 132 is reduced, and it is possible to prevent breakage such as cracks from occurring even if the installer is placed on the upper surface. The reinforcing rib 133 does not have to be in a lattice shape, but if it is in a lattice shape, the strength is preferably higher than that in one direction, and a hexagonal honeycomb lattice shape is more preferable in terms of strength.

  Further, the reinforcing rib 133 is formed with a space of a lower opening surrounded by the reinforcing rib 133, and an open portion 134 communicating with the upper portion of the space is formed. The opening 134 is configured such that a part of the reinforcing rib 133 is notched and communicates with the space of the adjacent lower opening. With this configuration, when inflow water such as river overflow water gradually accumulates and rises from below in the water storage space 110, air does not remain in the space of the lower opening, and the air is adjacent from the opening portion 134. The inflowing water can enter instead of moving to the space, and the floating of the filling member due to buoyancy can be prevented, and the water storage space 110 can be filled with rainwater to ensure a predetermined storage amount. It will be a thing. In addition, instead of the opening portion 134 in which the reinforcing rib 133 is cut out, a hole (not shown) penetrating the upper portion of the reinforcing rib 133 in the horizontal direction may be formed and communicated.

  Furthermore, the filling members 130 can be stacked at a large pitch by stacking the connecting members 135 on top of the connecting portions 131. The connecting member 135 connects the triangular pipe-shaped connecting portion 131. As shown in FIG. 8, the upper large triangular pipe-shaped connecting portion 136 externally fits the lower column portion 131b of the filling member 130 and the lower small portion. The substantially triangular pipe-shaped connecting portion 137 is configured to be fitted into the upper column portion 131 a of the filling member 130. By adjusting the height of the connecting member 135, the pitch at which the filling members 130 are stacked can be arbitrarily set. Although not shown, two kinds of filling members, that is, a filling member having a large connecting portion and a small filling member may be prepared and stacked at a small pitch or a large pitch. The connecting portion 137 is partially cut out, but may be continuous.

  In addition, the connecting member 135 includes a horizontal joint 138 on the outer perpendicular surface. One of the vertical surfaces is formed with a protruding projection 138a, and the other vertical surface is formed with a bonding hole 138b into which the bonding projection 138a is fitted. The joint convex portion 138a is composed of a root small diameter portion having the same diameter as that of the joint hole and a large diameter portion having an inclined tip at the top, and a slit is formed between the small diameter portion and the large diameter portion. The large diameter portion can be curved inward to reduce the diameter. With this configuration, the joint protrusion 138a is fitted and held in the joint hole 138b, and the connecting members 135 can be joined in the horizontal direction. The connecting member 135 includes an inclined partition plate for guiding earth and sand to the inclined plate portion 132, and a through hole 139 is formed at a lower position of the partition plate, so that rainwater can enter and air can be discharged. ing.

  As shown in FIG. 9A and FIG. 10A, the connecting member 135 can join the two connecting members 135 by fitting the joint convex portion 138a of the joint portion 138 into the joint hole 138b. it can. The two connecting members joined in this way are used when the filling member 130 is located on the outer peripheral side of the water storage space 110. Further, as shown in FIGS. 9B and 10B, the four connecting members 135 can be joined by fitting the joint projection 138a of the joint 138 into the joint hole 138b. In this case, it is used when the filling member 130 is located on the center side of the water storage space 110. In addition, what protrudes in the joint convex part 138a which is not used may be cut | disconnected with a blade etc., and may be flat. Further, when the filling member 130 facing the corners of the square manholes 115 and 116 is joined, although not shown, three connecting members are joined and used.

In the present embodiment, the filling member 130 and the connecting member 135 are used to assemble the water storage space 110 in the vertical direction in the portion excluding the square manholes 115 and 116 on both ends of the recess 111 as follows. It has been.
That is, the four filling members 130 in the vertical line at the left end in FIG. 3 are arranged so that the inclined direction S1 for guiding the inflowing water is directed rightward, that is, directed toward the concave portion 111 at the center of the water storage space 110. The four filling members 130 in the vertical line at the right end are also arranged so that the inclination direction S1 is directed leftward and directed toward the concave portion 111 at the center of the water storage space 110. The four filling members 130 in the second vertical line from the left end are arranged so that the inclination direction S is downward S3, rightward S1, upward S4, upward S3 in order from the top, and the second vertical line from the right end. The four filling members 130 are arranged so that the inclination direction S is downward S3, leftward S1, leftward S1, and upward S3 in order from the top. The center upper filling member 130 is disposed such that the inclination direction S is downward S2 in the figure, and the center lower filling member 130 is disposed leftward S3.

  The inclination direction is determined as follows. First, the inclination direction S <b> 1 of the filling member 130 is directed to the recess 111. Secondly, the filling member 130 located on the upper portion of the recess 111 is directed toward the outflow side as in the inclination direction S2. Thirdly, in the manholes 115 and 116 which are communication paths, the inflowing water escapes in another direction as in the inclined direction S3 so as not to reach a dead end. And it is set as the inclination direction S4 so that the inclination direction of the adjacent filling member may not face 4th. As a result, in the manhole part on the outflow side, a part of the inflowing water is configured to generate a swirl flow S5 that swirls clockwise and gradually falls from the gap of the inclined plate part. Note that the swirl flow may be counterclockwise from the center to the right by setting the tilt direction S3 to the right and the tilt direction S4 of the right filling member to the upward.

  Since it is configured as described above, the inflow water is guided toward the concave portion 111 at the center by the filling member 130, and gradually falls toward the concave portion 111 and is guided. In the case where the filling members 130 are stacked at a small pitch, the inclined plate portion 132 is continuous with the inclined plate portion 132 in the lower guiding direction with a slight step, and the inflow water can be continuously guided.

  For example, if the filling members 130 are stacked in seven stages at a small pitch and then stacked in four stages at a large pitch, the lower half corresponding to the foundation is stacked at a small pitch to increase the strength, and the upper half is at a large pitch. The porosity is large. Further, when the filling member 130 is stacked high, it becomes unstable. However, since the upper filling member 130 is joined in the horizontal direction at the joint portion 138 of the connecting member 135, the construction is stable and the construction is easy. Furthermore, since the filling member 130 is stable in the stacked state, the upper covering member 140 can be stably supported.

  The filling member 130 is required to have a high porosity per unit volume, to have practically sufficient strength and durability, and to be easy to carry and maintain and easy to maintain. The load resistance is preferably 5 to 20 tons per square meter in the vertical direction, 5 to 16 tons in the horizontal direction, and the porosity is preferably about 90%.

  After the filling member 130 is vertically stacked and installed as described above, the wall material 120 that covers the side surface of the filling member 130 is erected, and the waterproof sheet 121 is disposed vertically on the outer side, and further on the outer side. A backfilling material 122 such as gravel or crushed stone is filled between the excavation part 102. The wall material 120 prevents the waterproof sheet 121 located on the outside from entering the water storage space 110. The waterproof sheet 121 uses a synthetic rubber or resin-based sheet equivalent to that laid on the bottom surface of the water storage space 110 and is joined to the waterproof sheet 112 on the bottom surface with a fusion or waterproof adhesive so as not to leak. Yes. In order to protect the waterproof sheet 121 from the backfill material 122 such as gravel, a protective plate 123 equivalent to the wall material 120 may be disposed outside the waterproof sheet 121.

An overflow pipe 127 protrudes from the upper part of the water storage space 110, and a stored water suction pipe 128 protrudes from the lower part of the water storage space 110.
The overflow pipe 127 can discharge the inflow water from the overflow pipe 127 when the level of the inflow water stored in the water storage space 110 becomes higher than the overflow pipe 127.
As shown in FIG. 1, the stored water suction pipe 128 is connected to a first filtration device 42 described later.

  A covering member 140 covers the upper opening of the water storage space 110. The covering member 140 includes a covering board 141 placed on top of a large number of filling members 130, a waterproof sheet 142 laid thereon, and a backfill layer 143 backfilled thereon. Although not shown, it is preferable that the covering board 141 has a recess in which the upper connecting portion of the filling member 130 is fitted, so that the covering board 141 can be stably placed on the filling member. The communication port 117 is fixed at a position corresponding to the square manholes 115 and 116 of the covering board 141. Then, the waterproof sheet 142 is joined to the communication port 117, and the waterproof sheet 142 and the side waterproof sheet 121 are overlapped and joined at the side. As a result, the recess 111 opens to the ground through the rectangular manholes 115 and 116 and the communication port 117, and a hose such as cleaning water or vacuum can be inserted from the communication port 117 so that the tip of the hose can reach the recess 111. . The communication port 117 is normally closed by a lid (not shown). A protective board 144 or a protective sheet may be laid on the waterproof sheet 142.

In this way, the water storage space 110 is constituted by the waterproof sheet 112 on the bottom surface, the waterproof sheet 121 on the side surface, and the waterproof sheet 142 of the covering member 140 on the top surface. Then, it is backfilled in the same plane as the ground 1 by the backfill layer 143 of the covering member 140. The covering member is not limited to the above-described configuration, and may be a configuration in which a concrete plate or the like is simply arranged above the filling member.
And since the sedimentation tank 100 is as described above, when the sedimentation tank 100 is empty, the muddy water 48 from which large foreign matters have been removed through the filter-equipped 126 is provided with four introduction pipes 125. To the water storage space 110 so as to be received on the inclined plate portion 132 of the filling member 130 arranged at the uppermost stage of the water storage space 110 of the settling tank 100.

The muddy water 48 that has flowed into the water storage space 110 finally flows into the concave portion 111 while transferring to the inclined plate portion 132 of the lower filling member 130 due to the inclination of the inclined plate portion 132 of the filling member 130.
Even if the water level of the muddy water 48 that has flowed in rises from the upper end of the concave portion 111, the easily settleable particles in the muddy water 48 that has flowed in are successively placed in the lower filling member due to the inclination of the inclined plate portion 132 of the filling member 130. Finally, it flows into the recess 111 while transferring to the 130 inclined plate portions 132.

  That is, the easily settleable particles in the muddy water 48 that flow in one after another accumulate in the recess 111. Moreover, even if a large amount of muddy water 48 flows into the sedimentation tank 100 at one time, the water storage space 110 is partitioned into multiple layers by the inclined plate portion 132 of the filling member 130, and the concave portion 111 is formed by the gentle inclination of the inclined plate 132. Since it flows down in the direction, the flow down speed becomes slow, and it is possible to suppress the easy sedimentation particles already deposited in the recess 111 and the vicinity thereof.

  On the other hand, the easily settleable particles accumulated in the concave portion 111 are settled by inserting a hose H such as a vacuum from the communication port 117 and causing the tip of the hose H to reach the concave portion 111 and sucking it up. It can be easily removed from the tank 100.

  The first filtration device 42 uses a microfiltration membrane (MF), an ultrafiltration membrane (UF), a reverse osmosis membrane (RO) or the like as a filter medium, and is almost difficult due to sedimentation of easily settleable particles. The supernatant water collected in the water storage space 110 of the settling tank 100, which has become suspended water composed of settling particles, is supplied from a stored water suction pipe 128 to the rear of the filtered water outlet of the filtration device 42 (not shown). ), The hard-to-settling SS is removed by the filter medium, and the purified filtered water is once stored in the tank or discharged as it is.

In addition, after the continuous removal operation from 20 minutes to 1 hour, the filtration device 42 stops suction by the vacuum pump, and after being back-washed for a short time so as to eliminate clogging of the filter medium, the suction is again performed by the vacuum pump. The operation is repeated.
In other words, backwashing is performed by flowing separately prepared fresh water or filtered water stored in the tank as described above in the direction opposite to the filtration direction. In addition to the reduction, the concentration of hardly settled particles is increased in the filtration device 42.

  In addition, when removing the hard-to-seduce SS that has been sucked into and separated from the outside of the hollow fiber as a filter medium, the outer surface of the filter may be bubbled and washed. Foam may be passed through a hole such as a woodstone, or may be generated by refining air using a Venturi tube, or by opening a swirling flow method or a pressure-dissolved one, or using ultrasonic cavitation.

And the filtration apparatus 42 will be stopped if the difficulty sedimentation SS density | concentration in the filtration apparatus 42 rises and the filtration pressure becomes more than predetermined.
After the filtration device 42 is stopped, the high-concentration suspension water remaining in the filtration device 42 is processed by the suspension water treatment device 43.
That is, the suspension water treatment device 43 includes a sedimentation tank 43a and a pipe 43b for sending the high-concentration suspension water remaining in the filtration device 42 to the sedimentation tank 43a by the pump 44.

  Although not shown, the pipe 43b includes a large number of baffle plates inside, and the treated water is sent while being stirred between the baffle plates, and the viscosity of the natural material system is placed in the middle of the pipe 43b. A viscous polymer material supply unit that supplies the polymer material into the pipe 43b, and a polyvalent metal salt supply unit that supplies the polyvalent metal salt powder or a semi-saturated aqueous solution thereof into the pipe 43b are sequentially provided. That is, after the high-concentration suspended water and the viscous polymer material are rapidly stirred while being conveyed by the pipe 43b, the mixed solution and the polyvalent metal salt powder or its semi-saturated aqueous solution are rapidly stirred, SS in the concentration suspension water aggregates and is sent to the precipitation tank 43a.

  Each baffle plate has a size of 20% to 70% of the inner cross-sectional area of the pipe 43b, is supported by a support provided in the pipe 43b, and is 0.5 to 2 times the inner diameter of the pipe 43b. It is arranged with a double interval, and the angle is shifted by 90 degrees with respect to the major axis of the baffle plates adjacent in the pipe axis direction of the pipe 43b.

  The settling tank 43a is supplied with treated water containing aggregates discharged from the pipe 43b, precipitates the aggregates at the bottom of the settling tank 43a, and allows the supernatant water to be discharged into a river or ocean by overflow. .

The second filtration device 45 dehydrates and filters the aggregated sediment accumulated at the bottom of the sedimentation tank 43a. The fresh water obtained by filtration is discharged into rivers and oceans, or used as backwash water for the filtration device 42.
The storage tank 46 is configured to store a low moisture solid content obtained by the filtration device 45.

  In the present embodiment, the suspended water treatment device 43, the pump 44, the second filtration device 45, and the storage tank 46 are mounted on the loading platform portion of the truck 47 and are movable together with the truck 47.

  According to the purification method using this treatment system, as described above, since the supernatant water containing SS in the sedimentation tank 100 is filtered by the first filtration device 42 that is membrane filtration, the resulting fresh water There are no chemicals inside, and even if it is released as it is, it will not pollute the river or the ocean.

  In addition, since the supernatant water filtered by the filtration device 42 contains only the non-sedimentable SS, it is possible to reduce not only the filtration device 42 but also the failure of the pump. The accompanying cost can be reduced.

  In addition, since a natural material system is used for the flocculant, the drug dissolved in the fresh water after the flocculent filtration has a remarkably small environmental load. Furthermore, since the aggregated particle size is large, there is no clogging even when the nonwoven fabric is dehydrated, and the apparatus becomes simple. Further, the water content of the solid after dehydration is 30 to 40% by weight, and the capacity for recovery can be small. As a result, the entire equipment of the suspension water treatment device 43, the pump 44, the second filtration device 45, the storage tank 46, etc. is reduced, and the suspension water treatment device 43, the pump 44, the second filtration device 45, the storage tank 46, etc. Can be transported by loading on the

Therefore, it is unnecessary to permanently install the suspension water treatment device 43, the pump 44, the second filtration device 45, the storage tank 46, etc. adjacent to the settling tank 41, and the sludge in the plurality of settling tanks 41 is periodically removed. Will be able to. As a result, labor costs can be reduced and equipment costs can be reduced, and various advantages can be obtained such as facilitating repairs at the time of failure, prevention of artificial and natural failures and interference, and prevention of running out of drugs.
Furthermore, since periodic collection work including dredging becomes possible, stable operation as a local business becomes possible, and planned operation becomes possible. As a result, it is possible to remove sediments and the like in a planned manner, so that it is possible to contribute to the planned reef restoration plan for the remote islands in the south and the yearly budget for the local government.

  The truck 47 may periodically circulate and process the hardly sedimentable particles in the plurality of sedimentation tanks 100, or may treat the specific sedimentation tank 100. In order to achieve stable work, it is preferable from the viewpoint of cost and personnel arrangement that the plurality of settling tanks 100 are periodically circulated.

The aggregating agent may be mechanically stirred by a propeller, a pump, or the like. However, from the viewpoint of securing space on the loading platform and mechanical maintenance, as described above, in the pipe 43b by natural flow as described above. Aggregation is preferably performed by kneading.
The suspension water treatment device 43, the pump 44, the second filtration device 45, the storage tank 46, etc. may be fixed when the treatment frequency is high, but the normal treatment frequency is higher than the operation rate of the filtration device. Since it becomes low, it is preferable to make it movable as described above.

  In addition, the filling member 130 having the inclined tank portion 132 having a substantially square plate shape in plan view and having the inclined plate portion 132 inclined to one side forms a gap between the inclined plate portion 132 and the inclined plate portion 132. Since the water storage space 110 is assembled in a state of being stacked in a plurality of stages in the vertical direction, even if a large amount of muddy water flows into the sedimentation tank 100 at a time due to heavy rain or the like, the sediment that has settled first is wound up. There is nothing to do.

FIG. 11 shows a second embodiment of the method for purifying muddy water according to the present invention.
As shown in FIG. 11, in this purification method, after precipitating easily settled particles in the settling tank 100, the supernatant water 3 is transferred to the pretreatment tank 4. In addition, when the density | concentration of the difficulty sedimentation particle | grains in the supernatant water 3 exceeds 50000 ppm, it adjusts so that the density | concentration of a difficulty sedimentation particle may be 50000 ppm or less by dilution.

Next, viscous polysaccharides 5 such as alginate, pectin, glucomannan, fucoidan, etc., which are viscous polymer materials having easy dispersibility, are added to the suspension water 3 of the pretreatment tank 4 so that the concentration is 5 to 200 ppm. Although not shown, a mixed solution 6 is obtained by stirring and stirring uniformly with a stirrer.
Then, while stirring this mixed solution 6 with a stirrer (not shown) in the agglomeration treatment tank 7, granular calcium chloride fine powder (or a quasi-saturated aqueous solution of calcium chloride) 8 is poured into the agglomeration treatment tank 7 at once, A viscous polysaccharide is gelled by high polymerization, and fine sediment particles are entrained to obtain a large aggregate in a short time.

  Next, the supernatant water generated by the sedimentation of the agglomerates is discharged as it is, and the treated water containing the agglomerates accumulated at the bottom of the agglomeration treatment tank 7 at a high concentration is filtered by an endless belt type filtration device 9 and filtered. While discharging water, the agglomerates 10 remaining on the endless belt are collected.

FIG. 12 shows a third embodiment of the method for purifying muddy water according to the present invention.
As shown in FIG. 12, in this purification method, after precipitating easily settleable particles in the sedimentation tank 100, the suspension water 3 is stored in the agglomeration treatment tank 7, and first, the magnetic substance is stored in the agglomeration treatment tank 7. After the particles 25 and the viscous polysaccharide 5 are charged and stirred and uniformly dispersed by a stirrer 29, a granular calcium chloride fine powder (or a quasi-saturated aqueous solution of calcium chloride) 8 is further added to the mixed solution 7 The viscous polysaccharide is gelled in a highly polymerized state, and hardly settled particles are entrained to obtain a large aggregate in a short time.

Next, the treated water containing the agglomerates is poured into the agglomerate adsorption / removal device 30 to adsorb and remove only the agglomerates in the treated water.
That is, the adsorption removing device 30 includes a water tank 31, a cylindrical drum 32 made of a permanent magnet, and a blade 33, and can supply the aggregate that has settled at the bottom of the aggregation treatment tank 7 to the inlet of the water tank 31. Yes.

The water tank 31 includes a quarter semicircular arc-shaped bottom surface 31c whose inlet 31a side is higher than the outlet 31b side.
The cylindrical drum 32 is provided so as to form a gap S of about several millimeters between the bottom surface 31c and is rotated in the direction of the arrow X. When supplied to the water tank 31 from the inlet side, since the magnetic particles are included in the aggregate, the aggregate is adsorbed on the surface of the cylindrical drum 32 by the magnetic force of the cylindrical drum 32 while reaching the outlet of the water tank 31. Almost only water is discharged from the outlet.

  The agglomerates adsorbed on the surface of the cylindrical drum 32 are conveyed to the blade 33 in the adsorbed state and scraped off by the blade 33.

According to this purification method, agglomerates containing hardly sedimentable particles can be removed as a solid state with a low water content. In addition, small agglomerates that are slow to settle can be easily removed in a short time.
And since the removed agglomerates have a low water content, the drying process in the subsequent disposal or reuse process can be simplified.

The method for purifying muddy water of the present invention is not limited to the above embodiment.
For example, in the above embodiment, the inclined plate portion 132 of the filling member 130 is an example in which a flat plate is inclined. However, the inclined plate portion 132 is not a flat plate but is gently recessed along the inclined direction, or is gently bulged into a convex shape. It may be a curved surface or may be a stepped inclined surface with a small step and a continuous gradient. Furthermore, you may comprise the inclined surface which changes on the way from a steep slope to a gentle slope. The size of the filling member may be about 30 cm on a side or 1 m or more on a side.

In the above embodiment, the concave portion is a single location, but a plurality of concave portions are formed according to the width of the water storage space, and a plurality of concave portions are divided by the filling member to induce easily settleable particles. Good.
In the above embodiment, the hardly settleable particles peeled off from the filter medium surface by backwashing remain in the filter device, and the concentration of the hardly settled particles can be increased in the filter device. The supernatant water may be once transferred to another storage tank provided adjacent to the sedimentation tank, and backwash water may be returned to the storage tank to increase the concentration of hardly settled particles in the storage tank. .

It is a schematic diagram which illustrates typically an example of the processing system which implements the purification method of muddy water concerning this invention. It is sectional drawing of one Embodiment of the sedimentation tank of the processing system of FIG. It is the top view which abbreviate | omitted the coating | coated member of the sedimentation tank of FIG. It is the sectional view on the AA line of FIG. It is the perspective view which looked at the filling member used for the sedimentation tank of FIG. 2 from upper direction. It is the perspective view which looked at the filling member of Drawing 5 from the lower part. (A) is the BB sectional drawing of FIG. 5, (b) is CC sectional view taken on the line of FIG. The connection member used for the sedimentation tank of FIG. 2 is shown, (a) is the perspective view seen from the upper direction, (b) is the perspective view seen from the downward direction. (A) is a perspective view of the state which assembled two connection members of FIG. 8, (b) is a perspective view of the state which assembled four. (A) is a top view of the state which assembled two connection members of FIG. 8, (b) is a top view of the state which assembled four. It is a schematic diagram which illustrates typically 2nd Embodiment of the purification method of muddy water concerning this invention. It is a schematic diagram which illustrates typically 3rd Embodiment of the purification method of muddy water concerning this invention.

Explanation of symbols

3 Supernatant water 42 First filtration device 45 Second filtration device 48 Turbid water 100 Sedimentation tank 110 Water storage space 111 Recess 130 Filling member 132 Inclined plate portion

Claims (4)

After introducing turbid water containing suspended sediment of any one of river overflow water, river sediment turbid water and marine sediment turbid water into the sedimentation tank, the sedimentation tank settles the easily settleable particles, and then the sedimentation tank A method for purifying turbid water that purifies supernatant water containing hardly settled particles in the interior,
The settling tank has a water storage space, and a filling member having a plate shape of a substantially square shape in plan view and having an inclined plate portion inclined to one side forms a gap between the inclined plate portion and the inclined plate portion, and facilitates The muddy water is filled in the water storage space in a state of being stacked in a plurality of stages in the vertical direction so that the settling particles flow down toward the bottom of the water storage space along the inclined surface of the inclined plate portion. Purification method.   A recess is provided at the bottom of the water storage space, and a filling member can be assembled in the water storage space so as to form a path that guides easily settleable particles in muddy water flowing into the settling tank to the recess by the inclination of the inclined plate portion. The method for purifying muddy water according to claim 1.   The method for purifying muddy water according to claim 1 or 2, further comprising a step of coagulating and precipitating suspended components by adding a flocculant to the supernatant water, and subjecting the resulting precipitate to solid-liquid separation using a dehydration filtration apparatus.   A step of separating the supernatant water into filtered water and a suspension containing high-concentration hardly settled particles using a first filtration device, and adding a flocculant to the suspension containing high-concentration difficult-precipitation particles and coagulating and precipitating The method for purifying muddy water according to claim 1, further comprising a step of subjecting the obtained precipitate to dehydration filtration with a second filtration device and solid-liquid separation.