JP2015203210A - Sludge dredging method in enclosed area - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dredging method for sludge sedimented and adhered on the bottom surface of a river, lake, pond and others, in a highly efficient and safe manner and at a low cost, without propagating contamination when the sludge is rolled up.SOLUTION: A sludge dredging method comprises the steps of: submerging an excavation casing underwater from above in an area in a river and others where sludge has accumulated, and causing the lower edge of the casing to penetrate into the sludge layer, the excavation casing having an upper opening that may be opened/closed with a lid and an open bottom end; excavating the sludge layer in the excavation casing for separating and dispersing the sludge in water; mixing a biodegradable coagulation agent into the sludge layer and stirring the sludge layer for coagulating the excavated and separated sludge; carrying out the coagulated sludge outside from the excavation casing; and shifting the excavation casing over an adjacent area.

Description

  The present invention relates to the improvement of sludge dredging methods deposited on the bottom of rivers, lakes, ponds, etc., and in particular, water pollution and bad odor caused by sludge dredging in boat races and ponds in parks. The present invention relates to a sludge dredging method capable of discharging and removing sludge with high efficiency while effectively preventing occurrence.

To restore the environment of polluted rivers and lakes, remove pollutants in the water to improve the quality of the water itself, and remove sludge deposited on the bottom of the river to generate odors and polluted water. It is necessary to prevent re-diffusion (re-floating) inward.
In particular, since the latter accumulated sludge is present under anaerobic conditions, it generates methane gas and bad odor, and adversely affects aquatic organisms. For example, in a boat race track or the like, a bad odor occurs in the summer due to water contamination, and the event itself is affected.

For this reason, various purification technologies for rivers have been developed and put into practical use. FIG. 5 shows an example of this, and the coagulation agent B is ejected into the river water from the coagulation agent B and the drug mixing / injection device C mounted on the small vessel A, and the coagulation agent B is agglomerated by the screw of the vessel A or the like. While collecting and mixing the drug B into the water, the pollutant (flocculated block) that has been aggregated by the stirring of the flocculant B and floated in the water is collected in the recovery tool D composed of the mesh-like thin plate body D ₁ towed by the ship A. A method for purifying water in rivers and the like, which is attached to the outer surface and thereby collects aggregates (floc) floating in the water, has been developed and put into practical use (Japanese Patent Laid-Open No. 2005-205281, specially No. 2006-142183).

In the water purification method shown in FIG. 5, the contaminants floating in the water can be removed relatively efficiently.
However, it is difficult to remove sludge deposited and fixed on the bottom of rivers, etc. In order to collect and remove sludge accumulated and fixed by the construction method, first, the accumulated sludge etc. is agitated and resuspended in water. Next, after the coagulant B is agitated and mixed with this to make the sludge that floats as an aggregate (floc), it is necessary to collect the aggregate (floc) with the recovery tool D, and the work efficiency and economy From the point of view of practicality, its practical application is extremely difficult.

  Therefore, in reality, the removal of sludge accumulated and fixed on the riverbed (river bottom) has been carried out using a dredger (base ship A) equipped with an excavator, a towing bucket, a hopper, a suction pump, and the like. In general, so-called excavation and dredging methods are widely used.

  FIG. 6 shows an example of this kind dredger A using a suction pump, and a suction pipe F for sucking sediments (sludge) E deposited on the bottom of the water to a trolley A that performs dredging such as rivers and lakes. And a flat plate G that covers the surface of the accumulation sludge E is provided at the suction port at the tip of the suction pipe F, and the accumulation sludge E on the lower surface side of the flat plate G is sucked and trapped while the carriage A is moved. It is configured.

  Similarly, FIG. 7 shows an example of a dredging device H used for excavation and removal of sludge E or the like deposited on the river bottom. The dredging device H is connected to the tip of the carriage A via a ladder I. The sludge E which is attached so as to be movable up and down and excavated by the excavator J is carried out through the screw conveyor K, the flexible pipe L, and the discharge pipe M.

  However, sludge dredging using excavation and excavation suction dredging devices such as those shown in FIGS. 6 and 7 and the like, the surrounding water area is remarkably spread over a wide area due to sludge that rolls into the water during excavation and excavation of sludge. There is a basic problem that it will be polluted, and especially the negative effects on aquatic organisms due to hypoxia will be significant.

JP 2006-2050281 A JP 2006-142183 A WO2008-105521 JP 2005-48358 A JP-A-6-146337

  In the present invention, the problem as described above in the sludge trapped and fixed on the bottom surface of a river or the like, that is, the sludge deposited and fixed on the bottom surface of a river or the like is diffused by stirring, and then the flocculant is mixed with stirring. In the sludge dredging method using a method that collects agglomerates (floc) and a dredger equipped with a suction pump, excavator, etc., a large amount of sludge is rolled up at the time of excavation dredging and excavation, To solve the problem of causing environmental pollution around rivers due to deterioration of water quality and odor, etc., and to provide a sludge dredging method that can almost completely prevent the occurrence of such environmental pollution during sludge This is the main object of the invention.

  In the invention of claim 1, the upper opening is opened and closed by the upper lid and the excavation casing having the lower opening is submerged into the water from above the area where the sludge layer accumulates, and the lower end portion penetrates into the sludge layer. Next, the sludge layer in the excavation casing is excavated and separated and dispersed in water, and the biodegradable aggregating agent is mixed and stirred to agglomerate the sludge that has been excavated and separated. The basic configuration of the present invention is that the excavation casing is moved onto an adjacent area after being carried out from the inside to the outside.

  According to a second aspect of the present invention, in the first aspect of the present invention, a machine room is attached to the outside of the excavation casing, and the coagulant chemical is fed into the pressure water supply pump, the coagulation chemical tank, and the pump pressurized water in the machine chamber. In addition to providing an ejector-type mixer to be mixed, a pressure water injection nozzle is provided below the trunk of the drilling casing, and pressure water mixed with the aggregating agent is jetted from the pressure water injection nozzle into the sludge layer in the drilling casing. Thus, the sludge layer is excavated and separated, and the sludge separated and dispersed and the aggregating agent are stirred and mixed.

The invention of claim 3 is the invention of claim 1 or claim 2, wherein the aggregating agent is a biodegradable aggregating agent mainly composed of γ-polyglutamic acid, and the inner volume of the excavated casing is 1 m ³ . On the other hand, 5 to 1000 gr of a flocculant is stirred and mixed.

The invention of claim 4 is the invention of claim 1 or claim 2, wherein the aggregating agent is a biodegradable magnetic aggregating agent mainly composed of γ-polyglutamic acid, and the inner volume of the drilling casing is 1 m. ³ to 5 to 1000 gr of a flocculant is mixed with stirring.

  According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the crushed casing is connected via a suction hose in which the aggregated sludge aggregate is connected to a screw conveyor or a suction pump disposed in the digging casing. It is intended to be carried out.

  The invention of claim 6 is the invention of claim 1, wherein the sludge layer in the excavation casing is excavated and separated by a sludge excavator disposed in the excavation casing.

  The invention of claim 7 is the screw conveyor according to claim 1 or claim 2, wherein the aggregating agent is a magnetic aggregating agent, and the agglomerated sludge aggregates are disposed in the excavating casing. It is carried out of the excavation casing by a mold screw conveyor.

  In the present invention, into the water from above the area where sludge layer such as rivers accumulates, the upper opening is opened and closed by the upper lid and the lower part of the excavation casing with the lower opening is sunk into the sludge layer, Next, the sludge layer in the excavation casing is excavated and separated and dispersed in water, and the sludge that has been excavated and separated is agglomerated by mixing and stirring the biodegradable aggregating agent, and further, the sludge aggregate is excavated. After being carried out from the inside of the casing, the excavation casing is moved onto an adjacent area.

  For this reason, when the sludge layer deposited and fixed on the riverbed or the like is excavated, the rolled up sludge is limited to the inside of the excavation casing and does not contaminate other areas of the river.

  In addition, in the case of a configuration in which the sludge layer is excavated by injecting high-pressure water from an injection nozzle provided inside the excavation casing, a high-pressure water pump is simply used without using a large excavator. It is possible to efficiently excavate and separate sludge layers simply by installing them, and drastically reduce sludge dredging construction costs.

  Furthermore, since the biodegradable flocculant is stirred and mixed into the sludge separated by excavation to form sludge aggregates, the sludge aggregates are transported to the outside. Can be performed with high efficiency, and the flocculant itself is biodegradable and harmless, so that highly safe sludge is possible.

  In addition, when a magnetic flocculant (MGA) is used as the biodegradable flocculant, sludge aggregates can be recovered and carried out more efficiently by a screw conveyor or the like.

It is process explanatory drawing which concerns on one Embodiment of the area closed-type sludge dredging method by this invention. It is a slope view which shows an example of the setting condition of a digging casing. 3A is a schematic plan view showing an example of a digging casing, and FIG. 3B is a schematic cross-sectional view taken along the line II in FIG. It is a plane schematic diagram of the equipment room attached to the excavation casing. It is explanatory drawing of the collection | recovery method of the aggregate in water using the conventional flocculant. It is explanatory drawing of the sludge dredging method by the conventional suction method. It is explanatory drawing of the sludge dredging method by the conventional excavation method.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram of the construction process of the present invention. In FIG. 1, 1 is a drill casing installation process, 2 is a sludge drilling process, 3 is a flocculant mixing and stirring process, 4 is a sludge aggregation process, and 5 is a sludge. The agglomerate unloading step 6 is a digging casing moving step, and the present invention is constituted by the above steps.

  The excavation casing installation step 1 is a step of sinking a metal excavation casing, which will be described later, into a predetermined location such as a river or a lake. By submerging the excavation casing, an area where sludge excavation dredging is completely removed from other regions. The inside of the excavation casing will be a closed area.

In the excavation casing installation step 1, appropriate equipment / devices such as a carriage A, a crane that travels along the river bank, and the like are used according to the dredging target.
FIG. 2 shows a case where a digging casing 8 is installed when a crane boat 7 is used for sludge dredging in a type of racetrack that uses a part of the river, and the bottom of the river having a depth of about 5 to 10 m. The metal excavation casing 8 having a height H = 3 m, a width W = 10 m, and a length L = 10 m is submerged.

  Note that any device for suspending the excavation casing 7 may be used, and a crane or the like may be used depending on the construction site. In FIG. 2, 9 is a sludge layer deposited and fixed on the riverbed or the like. Here, the sludge layer deposited to a thickness of 2 to 3 m is removed.

  In the sludge excavation step 2, excavation and separation of the sludge layer 9 is performed by injecting river water at a high pressure into the sludge layer 9 deposited and fixed on the bottom of a river or the like located inside the submerged excavation casing 8. Agitation is performed.

  In the sludge excavation step 2 of FIG. 1, the sludge layer 9 is excavated and separated by ejecting high-pressure water from an injection nozzle using a submersible pump provided in a excavation casing 8 described later. However, it goes without saying that an excavator (not shown) may be suspended from the outside into the excavation casing 8 and the sludge layer 9 may be excavated mechanically using the excavator.

  The flocculant mixed stirring step 3 is a step of mixing and stirring and mixing the flocculant into the sludge that has been excavated and separated in the excavating step 2 and floating in the excavating casing 8, and in this embodiment, the sludge layer 9 is mixed. The flocculant is mixed into the pump suction water that is jetted for excavation, and the mixed water of the flocculant is jetted from the nozzle at a high pressure, thereby excavating the sludge layer 9 and stirring and mixing of the excavated sludge and water. To do at the same time.

Of course, after the sludge excavation step 3 is completed, it is of course possible to separately suspend a stirring mixer or the like in the drilling casing 8 and stir it with the stirring mixer while mixing the flocculant. .
The sludge separated by excavation is suspended in the water in the excavation casing 8 and hardly leaks out of the excavation casing 8.

  As the flocculant mixed into the excavation casing 8, a flocculant mainly composed of biodegradable γ-polyglutamic acid (trade name PGα21Ca, manufactured by Nihon Polyglu Co., Ltd.) is used. The flocculant in an amount of 5 to 1000 g (preferably 10 to 100 gr) is mixed.

  In addition, in order to facilitate the removal of sludge aggregates, which will be described later, a magnetic flocculant formed by mixing or binding magnetic material fine particles to γ-polyglutamic acid as the main flocculant (trade name) MGA, manufactured by Polyglu Co., Ltd.) may be used. In addition, the input amount to to-be-processed water is substantially the same as the case of the said flocculant (PG (alpha) 21Ca).

  The aggregating agent PGα21Ca and the magnetic aggregating agent MGA are already known from JP-A-2006-142183, JP-A-2006-205281, WO-2008-105521, and the like, and detailed description thereof is omitted here.

  When the aggregating and mixing step 3 of the flocculant is completed, the sludge aggregating step 4 is entered, and the mixture of sludge, flocculant and water excavated and separated in the excavating casing 8 is left still for 20 to 60 minutes. As a result, the fine sludges that have been excavated and separated are combined and agglomerated with each other via the flocculant, resulting in a relatively large sludge aggregate (floc) that floats and accumulates in the water below the excavation casing 8. .

  When the agglomeration step 4 is completed, the sludge agglomerates accumulated in the lower water of the excavation casing 8 are carried out of the excavation casing 8 in the unloading step 5 of the sludge agglomerates.

As a method for carrying out, a screw conveyor is inserted into the excavation casing 8 from the outside, and sludge aggregates are scraped up via the screw conveyor, or a vacuum pump is inserted by inserting the tip of the suction hose into the lower part of the excavation casing 8. how to suction and discharge the sludge aggregate by the view of the collection device D having the structure shown in 5 inserted into the drilled casing 8, by fixing the sludge agglomerates on the outer surface of the thin plate D ₁ of the collection device D A method of recovery is used.
In this embodiment, sludge aggregates are sucked and discharged by a vacuum pump.

  In addition, when the magnetic flocculant MGA is used, the sludge aggregate itself has magnetism, so that the agglomeration performance is remarkably improved and the screw body such as a screw conveyor is magnetized so that only the sludge aggregate is extremely reduced. It can be efficiently collected, scraped and discharged, and sludge aggregates can be discharged efficiently.

When the removal of the sludge aggregate is completed, in the excavation casing moving step 6, the excavation casing 8 is moved onto a predetermined adjacent area, and the sludge operation in the new divided area is started.
The excavation casing 8 may be moved by any method. In this embodiment, the casing 8 is pulled up until its lower end surface is located above the sludge layer at the bottom of the river, and then laterally moved. The casing 8 is moved so as to be landed.

  When the sludge accumulation layer is relatively thin, only one side of the excavation casing 8 is lifted slightly upward, and in this state, the lifted side is pulled to move the casing 8 to a predetermined position. By this method, the excavation casing 8 can be moved in the lateral direction without causing the sludge layer to roll up.

  3A and 3B show a digging casing 8 used in the practice of the present invention, in which FIG. 3A is a plan view of a state where an upper lid is opened, and FIG. 3B is a cross-sectional view taken along the line II in FIG. . FIG. 4 is a schematic plan view of the machine room 10 attached to the excavation casing 8.

  3 and 4, the excavation casing 8 is made of a steel plate, and has a rectangular cylindrical body (height H = 3 to 10 m, lateral width W = 5 to 15 m, vertical width L = 5 to 15 m) 11 And an upper lid 12 that is pivotally supported at the upper end of the body 11 so as to be openable and closable, and the bottom surface 13 of the body 11 is open.

That is, the upper surface side of the body portion 11 is an opening 14, and the upper opening 14 is opened and closed by the upper lid 12 that is pivotally supported by the support shaft 17 at the upper end of the opposite side wall.
In this embodiment, as shown in FIG. 3B, the upper lid 12 is formed in a split shape, but a single upper lid 12 may be used.

  Spring receivers 15, 15 serving as a total of four hooks are provided on both sides of the upper ends of the side walls 11 a, 11 b forming the body 11, and between the spring receiver 15 and the upper lids 12, 12, 16 is interposed. The springs 16 and 16 apply a pressing force in the closing direction to the upper lids 12 and 12.

  A pressure water injection nozzle 18, a pressure water supply 19, a pump water pipe 20, and the like are provided on the inner side of the trunk 11 that forms the excavating casing 8. The upper end of the pump water pipe 20 is It is located in the upper part of the trunk part 11.

  Further, a machine room 21 is airtightly provided at a side part below the trunk part 11 forming the excavation casing 8, and a pressure water supply pump 22, a flocculant tank, as shown in FIG. 23, the ejector-type mixer 24, the control panel 25, and the like are housed.

  As shown in FIG. 2, the excavating casing 8 suspended and supported by a crane or the like is moved above a predetermined area such as a river and lowered into water. Since the lower surface (bottom surface) of the casing body 11 is open, the casing 8 is sequentially submerged by its own weight, and the upper lids 12 and 12 are opened while the body 11 is lowered due to water pressure.

  When the lower end of the casing body 11 arrives at the river bottom and the lower end surface 11c penetrates into the sludge layer 9 due to its own weight and reaches the river bed surface or the like, the lids 12 and 12 opened at the time of lowering are springs. The vertical state is returned to the horizontal state by the elastic force of 16 and 16 and the weight of the lid body 12 itself, and the upper opening 14 of the trunk portion 11 is closed by the upper lid 12.

After that, sludge culling is performed according to each step shown in FIG.
In addition, when inserting a sludge excavator, sludge unloading screw conveyor, etc. into the excavation casing 8 from the outside, it is a matter of course that the upper lid 12 is opened and closed as necessary.

  The present invention can be applied not only to rivers, lakes and ponds but also to sludge basins such as the ocean.

A Carrier B Coagulation Agent 1 Drilling Casing Installation Process 2 Sludge Drilling Process 3 Coagulant Mixing Stirring Process 4 Sludge Aggregation Process 5 Sludge Aggregate Carrying Process 6 Drilling Cass Moving Process 7 Crane Ship 8 Drilling Casing 9 Sludge Layer 10 Machine Room 11 Body 11a, 11a Side wall 12 Upper lid 13 Bottom opening 14 Upper opening 15 Spring receiver 16 Spring 17 Support shaft 18 Pressure water injection nozzle 19 Pressure water supply pipe 20 Water absorption pipe 21 Machine room 22 Pressure water supply pump 23 Coagulant tank 24 Ejector type Mixer 25 Control panel

In the invention of claim 1, the upper opening is opened and closed by the upper lid and the excavation casing having the lower opening is submerged into the water from above the area where the sludge layer accumulates, and the lower end portion penetrates into the sludge layer. Next, the sludge layer in the excavation casing is excavated and dispersed in water, and the biodegradable aggregating agent is agitated and mixed to agglomerate the excavated and separated sludge. In an area-closed sludge construction method in which the excavation casing is moved onto an adjacent area after being transported to the outside, a machine room is attached outside the excavation casing, and pressure water is supplied to the machine room A pump, an aggregating chemical tank, and an ejector-type mixer that mixes the aggregating chemical into the pump pressurized water, and a pressure water injection nozzle below the trunk of the excavating casing are provided. By ejecting pressure water mixed with agent from the pressure water injection nozzle into the sludge layer in the drilling casing, that it has to perform stirring and mixing the drilling separation and separation dispersed sludge and flocculation agents for sludge layer This is a basic configuration of the invention.

The invention according to claim 2 is the invention according to claim 1, wherein the aggregating agent is a biodegradable aggregating agent mainly composed of γ-polyglutamic acid, and 5 to 5 m ³ of the inner volume of the drilling casing. 1000 g of the flocculant is mixed with stirring.

The invention of claim 3 is the invention of claim 1, wherein the aggregating agent is a biodegradable magnetic aggregating agent mainly composed of γ-polyglutamic acid, and the inner volume of the drilling casing is 1 m ³ . 5 to 1000 g of a flocculant is mixed with stirring.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the flocculated sludge aggregate is carried out of the digging casing through a suction hose connected to a screw conveyor or a suction pump disposed in the digging casing. It is a thing.

The invention of claim 5 is the invention of claim 1, wherein the sludge layer in the excavation casing is excavated and separated by a sludge excavator disposed in the excavation casing .

The invention of claim 6 is the invention of claim 1, wherein the aggregating agent is a magnetic aggregating agent, and the agglomerated sludge is agglomerated by a screw conveyor or a magnetizing type screw conveyor disposed in a drilling casing. It is intended to be carried out of the excavation casing .

Claims (7)

  The upper opening is opened and closed by the upper lid and the drilling casing with the lower opening is submerged into the water from the upper part of the area where the sludge layer accumulates. After the sludge layer is excavated and dispersed in water, and the biodegradable aggregating agent is stirred and mixed, the sludge separated by excavation is agglomerated, and further, the sludge aggregate is transported from the inside of the excavation casing to the outside. A closed area sludge dredging method characterized in that the excavation casing is moved onto an adjacent area.   A machine room is attached to the outside of the digging casing, and a pressure water supply pump, a flocculating chemical tank, and an ejector-type mixer for mixing the flocculating chemical into the pump pressurized water are provided in the machine room, and below the trunk of the drilling casing. A pressure water injection nozzle is provided on the side, and the pressure water mixed with the aggregating agent is ejected from the pressure water injection nozzle into the sludge layer in the excavation casing. 2. The closed area sludge dredging method according to claim 1, wherein the medicine is stirred and mixed. The coagulating agent is a biodegradable coagulant mainly composed of γ-polyglutamic acid, and ⁵ to 1000 gr of the coagulant is stirred and mixed with respect to 1 m ³ of the inner volume of the drill casing. Item 2. Closed area sludge dredging method according to item 2. The aggregating agent is a biodegradable magnetic aggregating agent mainly composed of γ-polyglutamic acid, and ⁵ to 1000 gr of the aggregating agent is stirred and mixed with respect to an inner volume of 1 m ³ of the drill casing. Alternatively, the closed area sludge dredging method according to claim 2.   The area-closed sludge according to claim 1 or 2, wherein the aggregated sludge is carried out of the excavation casing through a suction hose connected to a screw conveyor or a suction pump disposed in the excavation casing. Amber method.   The area-closed sludge dredging method according to claim 1, wherein the sludge layer in the excavation casing is excavated and separated by a sludge excavator disposed in the excavation casing.   3. The coagulation agent is a magnetic coagulant, and the aggregated sludge aggregate is carried out of the excavation casing by a screw conveyor or a magnetizing screw conveyor disposed in the excavation casing. The closed area sludge dredging method described in 1.

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