CN114214998B

CN114214998B - Method for removing cofferdam of polluted fishpond dike in lake

Info

Publication number: CN114214998B
Application number: CN202111284591.6A
Authority: CN
Inventors: 朱永涛; 肖伟华; 刘宏权; 白苓仙; 李源; 杨蒙; 李耀; 田园; 闫英师
Original assignee: HEBEI PROVINCIAL ACADEMY OF WATER RESOURCES
Current assignee: HEBEI PROVINCIAL ACADEMY OF WATER RESOURCES
Priority date: 2021-11-01
Filing date: 2021-11-01
Publication date: 2023-04-25
Anticipated expiration: 2041-11-01
Also published as: CN114214998A

Abstract

The invention relates to a method for clearing a dam of a polluted fishpond in a lake, which comprises the following steps: step 1, distributing at least one antifouling screen on two sides of a dam; the anti-fouling screen comprises a suspension body, an anti-fouling curtain fixedly arranged on the suspension body, and a plurality of balancing weights fixedly arranged at the bottom of the anti-fouling curtain; step 2, dismantling the dike cofferdam by adopting an antifouling dismantling ship, and transporting the sludge out of the water area; and 3, dismantling the anti-fouling screen after the water quality is stable. The invention solves the problem that pollutants are easy to diffuse in the process of dismantling the dam of the polluted fishpond.

Description

Method for removing cofferdam of polluted fishpond dike in lake

Technical Field

The invention belongs to the field of construction for removing a dike cofferdam, and particularly relates to a method for removing the dike cofferdam of a polluted fish pond in a lake.

Background

The construction of a dike cofferdam in a white lake water area for cultivation and planting has made an important contribution to local economy in historic long rivers. However, with the development of society, today, environmental ecology is more and more important, the cofferdam is removed, and the natural ecology of the water area is restored to be an essential link of the social development, however, in the process of removing the cofferdam, an excavator is usually adopted to remove the cofferdam, the excavator digs the soil of the cofferdam onto a transport vehicle, and the transport vehicle transports the soil. However, the excavator has great disturbance to the water body in the process of digging soil, and is easy to scatter some soil into the pond, so that serious secondary pollution is easily caused to the pond, and therefore, a method for removing the polluted fish pond dike cofferdam in the lake is urgently needed to be researched to solve the problem of removing the polluted fish pond dike cofferdam.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a method for removing the cofferdam of a polluted fishpond in a lake, which aims to solve the problem of dismantling the cofferdam of the polluted fishpond.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

a method for removing a dam of a polluted fish pond in a lake, comprising the following steps:

step 1, distributing at least one antifouling screen on two sides of a dam;

the anti-fouling screen comprises a suspension body, an anti-fouling curtain fixedly arranged on the suspension body, and a plurality of balancing weights fixedly arranged at the bottom of the anti-fouling curtain;

step 2, dismantling the dike cofferdam by adopting an antifouling dismantling ship, and transporting the sludge out of the water area;

and 3, dismantling the anti-fouling screen after the water quality is stable.

Further, the antifouling demolition vessel comprises a frame, a mud carrier fixedly arranged below the frame, a buoyancy tank mechanism and a demolition device which are arranged below the frame in a sliding manner, a connecting pipe for connecting the demolition device and the mud carrier, a first driving mechanism for driving the buoyancy tank mechanism to slide and a second driving mechanism for driving the demolition device to slide, wherein the mud carrier and the buoyancy tank mechanism are respectively arranged at two sides of the demolition device;

the dismantling device comprises a first mounting plate which is arranged on the rack in a sliding manner, a dismantling mechanism which is arranged below the first mounting plate through a first cylinder, the dismantling mechanism comprises a shell, a cleaning device, a crushing device and a conveying device which are sequentially arranged in the shell according to the direction of water flow, and a purifying agent storage box which is arranged above the first mounting plate, wherein a purifying agent inlet is arranged at a position on the shell corresponding to the crushing device, the purifying agent storage box is communicated with the purifying agent inlet through a purifying agent pipeline, and a valve is arranged on the purifying agent pipeline;

the buoyancy tank mechanism comprises a second mounting plate which is arranged on the frame in a sliding manner, and the buoyancy tank is arranged below the second mounting plate through a second air cylinder.

Further, the section of the position, corresponding to the cleaning device, on the shell is trapezoid, the inlet end is wide, and the outlet end is narrow;

the bottom of the shell, which corresponds to the cleaning device, is open;

the shell is provided with a mixing pipe at the outlet end of the conveying device, and the mixing pipe adopts a venturi;

the mud carrier is provided with a feed inlet, and the mixing pipe is communicated with the feed inlet through the connecting pipe;

and a sludge pump is arranged on the connecting pipe.

Further, the mud carrying ship comprises a sealed ship body, a support arranged in the ship body, a mud carrying cavity arranged below the support, and a spiral filter press arranged on the support, wherein the spiral filter press comprises a filter pressing shell, a feeding pipe and a discharging pipe arranged on the filter pressing shell, the feeding pipe extends out of the filter pressing shell and then is provided with a feeding hole, a filter pressing spiral mechanism is rotatably arranged in the filter pressing shell, one end of the filter pressing spiral mechanism extends out of the filter pressing shell and then is provided with a filter pressing motor for driving the filter pressing spiral mechanism to rotate, the bottom of the filter pressing shell is of a double-wall structure, so that a water flowing cavity is formed, a plurality of water leakage holes are formed in the upper wall of the double-wall structure, and a drain pipe is arranged on the lower wall of the double-wall structure and extends out of the ship body and then is provided with a water outlet.

Still further, filter-pressing spiral mechanism include the third pivot, set up in the epaxial filter-pressing spiral of third, the pitch of filter-pressing spiral is close to the one end of inlet pipe big, and the one end that is close to the discharging pipe is little.

Further, a ship door is further arranged on the ship body.

Further, a purifying agent is arranged in the purifying agent storage box, the purifying agent is prepared before use, and the purifying agent comprises the following components in parts by weight:

further, the preparation method of the purifying agent comprises the following steps:

step 1, dissolving sodium persulfate with a small amount of water to prepare sodium persulfate solution;

step 2, after the diatomite is dried and activated at 200 ℃, adding sodium persulfate solution into the diatomite, and mixing for 15min;

and step 3, adding diatomite mixed with sodium persulfate and the nano titanium dioxide modified hydroxyethyl cellulose flocculant into the rest water, and stirring and dispersing uniformly.

Further, the preparation method of the nano titanium dioxide modified hydroxyethyl cellulose flocculant comprises the following steps: dissolving hydroxyethyl cellulose in dimethyl sulfoxide according to the mass ratio of 1:5, and then mixing the hydroxyethyl cellulose, nano titanium dioxide and benzhydryl amine according to the mass ratio of 1:0.1:0.5, adding nano titanium dioxide into the mixture, heating the mixture to 50 ℃ for reaction for 15min, cooling the mixture, then adding benzhydryl amine into the mixture, continuously stirring the mixture for reaction for 30min, adjusting the pH value of the mixture to 5-8, and stopping the reaction to obtain the nano titanium dioxide.

In step 2, the method for dismantling the embankment bank by using the anti-fouling dismantling ship specifically comprises the following steps:

the method comprises the steps of placing a dismantling device of an antifouling dismantling ship above a cofferdam, placing a buoyancy tank and a dredger on two sides of the cofferdam respectively, rotating driving motors of a first driving mechanism and a second driving mechanism, driving a transmission shaft to rotate by the driving motors, and then driving a buoyancy tank mechanism and a dismantling mechanism to slide along a rack under the action of a gear III and a rack, so that the buoyancy tank mechanism and the dismantling mechanism are precisely positioned, starting a second cylinder to press the buoyancy tank onto the water surface, floating the buoyancy tank on the water surface, and supporting the buoyancy tank and the dredger together;

then starting a first cylinder, pressing the demolishing device down to the cofferdam, simultaneously starting a cleaning device, a crushing device, a conveying device and a filter pressing mechanism, opening a flocculating agent pipeline and a sludge pump,

the two cleaning mechanisms rotate in opposite directions, the cleaning plates scrape soil on the cofferdam into the conveying part, after the soil reaches the conveying part, the turntable of the stirring device drives the stirring rod to rotate, the stirring rod stirs large soil blocks in the soil, meanwhile, the flocculating agent entering the conveying part is primarily mixed with the soil, the stirred soil enters the conveying device, the stirred soil enters the mixing pipe under the pushing of the pushing screw of the conveying device, the soil and the flocculating agent are further mixed, and then the soil enters the filter pressing mechanism through the connecting pipe under the action of the sludge pump;

in the filter pressing mechanism, soil is extruded by a filter pressing screw to realize soil-water separation, water enters the water flowing cavity through the water leakage hole and is discharged out of the sludge carrying ship through the water discharging pipe, and the soil after water removal is discharged into the sludge carrying cavity through the water discharging pipe and is transported out of the water area.

Compared with the prior art, the invention has the beneficial effects that:

1. by arranging the anti-fouling barriers at the two sides of the cofferdam of the dike to be dismantled, the problem that pollutants spread to the surrounding water area in the process of dismantling the cofferdam of the polluted fishpond is avoided.

2. The invention improves the dismantling ship to ensure that the dismantling ship has an antifouling and purifying function, and solves the problem that the indexes of pollutants such as nitrogen and phosphorus are increased sharply in the dismantling process of the dam of the polluted fish pond.

3. According to the invention, the nano titanium dioxide modified hydroxyethyl cellulose flocculant is added into the purifying agent, so that the purifying capability of the purifying agent is improved, the nitrogen and phosphorus removal efficiency in water is improved, in addition, the water content of sludge in the dredger is reduced, the sludge capacity of the dredger is improved, and the carrying round trip times of the dredger are reduced.

The invention combines various measures to solve the problem of instant increase of pollutants in the process of demolishing the dam, improves the treatment effect of pollutants such as nitrogen and phosphorus in the sludge and avoids the pollution of surrounding water areas.

Drawings

FIG. 1 is a schematic view of an anti-fouling screen according to an embodiment of the present invention;

FIG. 2 is a perspective view of an anti-fouling removal vessel according to an embodiment of the invention;

FIG. 3 is an enlarged view at A of FIG. 2;

FIG. 4 is a perspective view of an alternate angle of the anti-fouling removal vessel in accordance with one embodiment of the present invention;

FIG. 5 is a perspective view of a removal device according to one embodiment of the invention;

FIG. 6 is a perspective view of a removal device (without a housing) in accordance with one embodiment of the present invention;

FIG. 7 is a schematic view of a dredger according to an embodiment of the present invention;

fig. 8 is a cross-sectional view taken along B-B of fig. 7.

1. The device comprises a rack, 2, a mud carrier, 3, a connecting pipe, 4, a first mounting plate, 5, a first cylinder, 6, a shell, 7, a dismantling device, 8, a crushing device, 9, a conveying device, 10, a purifying agent storage box, 11, a purifying agent pipeline, 12, a valve, 13, a second mounting plate, 14, a second cylinder, 15, a buoyancy tank, 16, a mixing pipe, 17, a feed inlet, 18, a ship body, 19, a bracket, 20, a mud carrying cavity, 21, a filter pressing shell, 22, a discharging pipe, 23, a filter pressing motor, 24, a water flowing cavity, 25, a water leakage hole, 26, a water discharging pipe, 27, a third rotating shaft, 28, a filter pressing spiral, 29, a rack, 30, a driving motor, 31, a transmission shaft, 32, a first gear, 33, a second gear, 34, a third gear, 35, a driving sprocket, 36, a driven sprocket, 37, a chain, 38, a cleaning motor, 39 and a cleaning plate; 40. the device comprises a rotary table, 41, a crushing rod, 42, a first rotating shaft, 43, a crushing motor, 44, a second rotating shaft, 45, a pushing spiral blade, 46, a conveying motor, 47, a suspension, 48, an anti-fouling curtain, 49, a balancing weight, 50 and a cleaning mechanism.

Detailed Description

The technical solutions of the present invention will be clearly and fully described below with reference to specific embodiments, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

The embodiment shows an antifouling demolition vessel, as shown in fig. 2-8, which comprises a frame 1, a mud carrier 2 fixedly arranged below the frame 1, a buoyancy tank mechanism and a demolition unit 7 slidingly arranged below the frame 1, a connecting pipe 3 for connecting the demolition unit 7 and the mud carrier 2, a first driving mechanism for driving the buoyancy tank mechanism to slide and a second driving mechanism for driving the demolition unit 7 to slide, wherein the mud carrier 2 and the buoyancy tank mechanism are respectively arranged at two sides of the demolition unit 7;

the dismantling device 7 comprises a first mounting plate 4 arranged on the frame 1 in a sliding manner, a dismantling mechanism arranged below the first mounting plate 4 through a first air cylinder 5, the dismantling mechanism comprises a housing 6, a cleaning device, a crushing device 8 and a conveying device 9 which are sequentially arranged in the housing 6 according to the direction of water flow, and a purifying agent storage box 10 arranged above the first mounting plate 4, a purifying agent inlet is arranged at a position on the housing 6 corresponding to the crushing device 8, the purifying agent storage box 10 is communicated with the purifying agent inlet through a purifying agent pipeline 11, and a valve 12 is arranged on the purifying agent pipeline 11;

the buoyancy tank mechanism comprises a second mounting plate 13 which is arranged on the frame 1 in a sliding manner, and a buoyancy tank 15 which is arranged below the second mounting plate 13 through a second air cylinder 14.

Further, the section of the position, corresponding to the cleaning device, on the shell 6 is trapezoid, the inlet end is wide, and the outlet end is narrow;

the bottom of the shell 6, which corresponds to the cleaning device, is open;

a mixing pipe 16 is arranged at the outlet end of the conveying device 9 on the shell 6, and the mixing pipe 16 adopts a venturi;

the mud carrier 2 is provided with a feed inlet 17, and the mixing pipe 16 is communicated with the feed inlet 17 through the connecting pipe 3.

Further, the dredger 2 includes airtight hull 18, set up in support 19 in the hull 18, set up in the mud carrying cavity 20 of support 19 below, set up in screw press on the support 19, screw press includes filter-pressing housing 21, set up in inlet pipe and discharging pipe 22 on the filter-pressing housing 21, the inlet pipe extends set up behind the filter-pressing housing 21 feed inlet 17, filter-pressing housing 21 rotation is provided with filter-pressing screw mechanism, filter-pressing screw mechanism's one end extends behind the filter-pressing housing 21 sets up the drive filter-pressing screw mechanism pivoted filter-pressing motor 23, the bottom of filter-pressing housing 21 is double-walled structure to form water flowing cavity 24, be provided with a plurality of holes 25 that leak on the upper wall of double-walled structure, the lower wall of double-walled structure is provided with drain pipe 26, drain pipe 26 extends set up the outlet behind the hull 18.

Further, the filter-pressing spiral mechanism comprises a third rotating shaft 27, and a filter-pressing spiral 28 arranged on the third rotating shaft 27, wherein the pitch of the filter-pressing spiral 28 is large at one end close to the feeding pipe, and is small at one end close to the discharging pipe 22.

Further, a door is also provided on the hull 18.

Further, the first driving mechanism and the second driving mechanism have the same structure and comprise racks 29 arranged on the frame 1, driving motors 30 arranged on corresponding mounting plates and transmission shafts 31, a first gear 32 is arranged on the driving motors 30, a second gear 33 and a third gear 34 are arranged on the transmission shafts 31, the first gear 32 is in meshed connection with the second gear 33, and the third gear 34 is in meshed connection with the racks 29.

Further, the cleaning device comprises 2 cleaning mechanisms 50 symmetrically arranged, wherein the cleaning mechanisms 50 comprise a driving sprocket 35 and a driven sprocket 36 which are rotatably arranged in the shell 6, a chain 37 arranged on the driving sprocket 35 and the driven sprocket 36, a cleaning motor 38 for driving the driving sprocket 35 to rotate, and a plurality of cleaning plates 39 arranged on the chain 37;

the crushing device 8 comprises two turntables 40 rotatably arranged in the shell 6, a plurality of crushing rods 41 connected with the two turntables 40, a first rotating shaft 42 arranged on at least one turntable 40, and a crushing motor 43 arranged at one end of the first rotating shaft 42 extending out of the shell 6;

the conveying device 9 comprises a second rotating shaft 44 rotatably arranged in the housing 6, a pushing spiral blade 45 fixedly arranged on the second rotating shaft 44, and a conveying motor 46 arranged at one end of the second rotating shaft 44 extending out of the housing 6.

Example 2

The embodiment shows an anti-fouling screen, as shown in fig. 1, comprising a suspension body 47, an anti-fouling curtain 48 fixedly arranged on the suspension body 47, and a plurality of balancing weights 49 fixedly arranged at the bottom of the anti-fouling curtain 48;

further, the suspension 47 employs an inflatable cord comprising a strip-shaped bag body, and air disposed within the strip-shaped bag body.

Example 3

The embodiment shows a purifying agent which comprises the following raw materials in parts by weight:

the preparation method of the nano titanium dioxide modified hydroxyethyl cellulose flocculant comprises the following steps: dissolving hydroxyethyl cellulose in dimethyl sulfoxide according to the mass ratio of 1:5, and then mixing the hydroxyethyl cellulose, nano titanium dioxide and benzhydryl amine according to the mass ratio of 1:0.1:0.5, adding nano titanium dioxide into the mixture, heating the mixture to 50 ℃ for reaction for 15min, cooling the mixture, then adding benzhydryl amine into the mixture, continuously stirring the mixture for reaction for 30min, adjusting the pH value of the mixture to 5-8, and stopping the reaction to obtain the nano titanium dioxide modified hydroxyethyl cellulose flocculant.

The purifying agent is prepared before use, and the preparation method of the purifying agent comprises the following steps:

Example 4

This example shows a method of clearing a dam of a polluted pond in a starching station comprising the steps of:

step 1, distributing at least one antifouling screen on two sides of a dam;

step 2, dismantling the dike cofferdam by adopting the antifouling dismantling ship in the embodiment 2, wherein the specific dismantling method is as follows:

the dismantling device 7 of the antifouling dismantling ship is arranged above the embankment cofferdam, the buoyancy tank 15 and the dredger 2 are respectively arranged on two sides of the embankment cofferdam, the driving motors 30 of the first driving mechanism and the second driving mechanism are rotated, the driving shafts 31 are driven by the driving motors 30 to rotate, then under the action of the third gear 34 and the rack 29, the buoyancy tank mechanism and the dismantling mechanism are driven to slide along the frame 1, after the buoyancy tank mechanism and the dismantling mechanism are accurately positioned, the second cylinder 14 is started to press the buoyancy tank 15 onto the water surface, the buoyancy tank 15 floats on the water surface, and the buoyancy tank 15 and the dredger 2 jointly play a supporting role;

then the first cylinder 5 is started, the demolishing device 7 is pressed down to the cofferdam, meanwhile, the cleaning device, the stirring device 8, the conveying device 9 and the filter pressing mechanism are started, the flocculating agent pipeline and the sludge pump are opened,

the two cleaning mechanisms rotate in opposite directions, the cleaning plates 39 scrape soil on the cofferdam into the conveying part, after the soil enters the conveying part, the rotary table 40 of the stirring device drives the stirring rod 41 to rotate, the stirring rod 41 stirs large soil blocks in the soil, meanwhile, the flocculating agent entering the conveying part is primarily mixed with the soil, the stired soil enters the conveying device 9, the soil enters the mixing pipe 16 under the pushing of the pushing screw of the conveying device 9, the soil is further mixed with the flocculating agent, and then the soil enters the filter pressing mechanism through the connecting pipe 3 under the action of the sludge pump; the flocculant adopts the purifying agent prepared in the example 3;

in the filter pressing mechanism, soil is extruded by a filter pressing screw 28 to realize soil-water separation, water enters a running water cavity 24 through a water leakage hole 25 and is discharged out of the dredger 2 through a water discharge pipe 26, and the soil after water removal is discharged into a mud carrying cavity through a discharge pipe 22 and is transported out of a water area;

and 3, dismantling the anti-fouling screen after the water quality is stable.

Comparative example 1

Step 1, distributing at least one antifouling screen on two sides of a dam;

step 2, demolishing the dike bank using the anti-fouling demolishing vessel as described in example 2, the specific demolishing method being the same as in example 4, except that the scavenger used is different,

the purifying agent adopted in the comparative example 1 comprises the following raw materials in parts by weight:

the purifying agent adopted in the comparative example 1 is prepared before use, and the preparation method is as follows:

and step 3, adding diatomite mixed with sodium persulfate and a commercially available hydroxyethyl cellulose flocculant into the rest water, and stirring and dispersing uniformly.

Comparative example 2

Step 1, distributing at least one antifouling screen on two sides of a dam;

the purifying agent adopted in the comparative example 2 comprises the following raw materials in parts by weight:

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and step 3, adding diatomite mixed with sodium persulfate and a commercially available polyaluminium chloride flocculant into the rest water, and stirring and dispersing uniformly.

Comparative example 3

Step 1, distributing at least one antifouling screen on two sides of a dam;

step 2, the embankment is removed by the antifouling removing vessel according to the embodiment 2, and the specific removing method is the same as the embodiment 4, except that the valve 12 on the purifying agent pipe 1 is always closed and the purifying agent is not supplied to the supplying part.

And 3, dismantling the anti-fouling screen after the water quality is stable.

Effect example 1:

in the dismantling construction process of the step 2 in the embodiment 4 and the comparative examples 1 to 3, respectively, sampling and measuring the water at the cofferdam of the embankment before, during and 24 hours after the dismantling construction (sampling adopts multipoint sampling and data processing in an average mode), detecting the change condition of total nitrogen and total phosphorus in the water at the cofferdam of the embankment, and simultaneously calculating the dehydration rate of sludge on the carrier in the embodiment 1 and the comparative examples 1 to 2 by taking the comparative example 3 without adding a purifying agent as a blank contrast; the results are shown in Table 1.

TABLE 1

The above described embodiments are only preferred examples of the invention and are not exhaustive of the possible implementations of the invention. Any obvious modifications thereof, which would be apparent to those skilled in the art without departing from the principles and spirit of the present invention, should be considered to be included within the scope of the appended claims.

Claims

1. A method for removing a dam of a polluted fish pond in a lake, comprising the steps of:

step 1, distributing at least one antifouling screen on two sides of a dam;

the anti-fouling screen comprises a suspension body (47), an anti-fouling curtain (48) fixedly arranged on the suspension body (47), and a plurality of balancing weights (49) fixedly arranged at the bottom of the anti-fouling curtain (48);

step 3, dismantling the anti-fouling screen after the water quality is stable;

the anti-fouling demolition vessel comprises a frame (1), a mud carrier (2) fixedly arranged below the frame (1), a buoyancy tank mechanism and a demolishing device (7) which are arranged below the frame (1) in a sliding manner, a connecting pipe (3) for connecting the demolishing device (7) and the mud carrier (2), a first driving mechanism for driving the buoyancy tank mechanism to slide and a second driving mechanism for driving the demolishing device (7) to slide, wherein the mud carrier (2) and the buoyancy tank mechanism are respectively arranged at two sides of the demolishing device (7);

the dismantling device (7) comprises a first mounting plate (4) arranged on the frame (1) in a sliding manner, a dismantling mechanism arranged below the first mounting plate (4) through a first air cylinder (5), the dismantling mechanism comprises a shell (6), a cleaning device, a stirring device (8) and a conveying device (9) which are sequentially arranged in the shell (6) according to the direction of water flow, and a purifying agent reserve tank (10) arranged above the first mounting plate (4), a purifying agent inlet is arranged at a position, corresponding to the stirring device (8), on the shell (6), the purifying agent reserve tank (10) is communicated with the purifying agent inlet through a purifying agent pipeline (11), and a valve (12) is arranged on the purifying agent pipeline (11);

the buoyancy tank mechanism comprises a second mounting plate (13) which is arranged on the frame (1) in a sliding manner, and a buoyancy tank (15) which is arranged below the second mounting plate (13) through a second air cylinder (14);

the purifying agent storage box (10) is internally provided with a purifying agent, the purifying agent is prepared before use, and the purifying agent comprises the following components in parts by weight:

diatomaceous earth: 10 parts;

sodium persulfate: 35 parts;

nano titanium dioxide modified hydroxyethyl cellulose flocculant: 10 parts;

water: 100 parts;

the preparation method of the purifying agent comprises the following steps:

step 3, adding diatomite mixed with sodium persulfate and a nano titanium dioxide modified hydroxyethyl cellulose flocculant into the rest water, and stirring and dispersing uniformly;

the preparation method of the nano titanium dioxide modified hydroxyethyl cellulose flocculant comprises the following steps: dissolving hydroxyethyl cellulose in dimethyl sulfoxide according to the mass ratio of 1:5, and then mixing the hydroxyethyl cellulose, nano titanium dioxide and benzhydryl amine according to the mass ratio of 1:0.1:0.5, adding nano titanium dioxide into the mixture, heating the mixture to 50 ℃ for reaction for 15min, cooling the mixture, then adding benzhydryl amine into the mixture, continuously stirring the mixture for reaction for 30min, adjusting the pH value of the mixture to 5-8, and stopping the reaction to obtain the nano titanium dioxide.

2. A method of removing a dam from a contaminated fish in a lake according to claim 1, wherein,

the section of the position, corresponding to the cleaning device, of the shell (6) is trapezoid, the inlet end is wide, and the outlet end is narrow;

the bottom of the shell (6) corresponding to the cleaning device is open;

a mixing pipe (16) is arranged at the outlet end of the conveying device (9) on the shell (6), and the mixing pipe (16) adopts a venturi;

the mud carrier (2) is provided with a feed inlet (17), and the mixing pipe (16) is communicated with the feed inlet (17) through the connecting pipe (3);

and a sludge pump is arranged on the connecting pipe (3).

3. A method of removing a polluted fish pond in a lake according to claim 2, wherein,

the mud carrying ship (2) comprises a sealed ship body (18), a support (19) arranged in the ship body (18), a mud carrying cavity (20) arranged below the support (19), a spiral filter press arranged on the support (19), the spiral filter press comprises a filter pressing shell (21), a feed pipe and a discharge pipe (22) arranged on the filter pressing shell (21), the feed pipe extends out of the filter pressing shell (21) and then is provided with a feed inlet (17), the filter pressing shell (21) is rotationally provided with a filter pressing spiral mechanism, one end of the filter pressing spiral mechanism extends out of the filter pressing shell (21) and then is provided with a filter pressing motor (23) for driving the filter pressing spiral mechanism to rotate, the bottom of the filter pressing shell (21) is of a double-wall structure, so that a water flowing cavity (24) is formed, a plurality of water leakage holes (25) are formed in the upper wall of the double-wall structure, a drain pipe (26) is arranged on the lower wall of the double-wall structure, and the drain pipe (26) extends out of the water outlet after the ship body (18).

4. A method of removing a polluted fish pond in a lake according to claim 3, wherein,

the filter-pressing spiral mechanism comprises a third rotating shaft (27), a filter-pressing spiral (28) arranged on the third rotating shaft (27), and the screw pitch of the filter-pressing spiral (28) is large at one end close to the feeding pipe and small at one end close to the discharging pipe (22).

5. A method of cleaning a polluted pond, dike, cofferdam in a lake according to claim 3, wherein said hull (18) is further provided with a gate.

6. A method of removing a dam from a contaminated fish in a lake according to claim 4, wherein,

in the step 2, the method for dismantling the dike cofferdam by adopting the antifouling dismantling ship comprises the following specific steps:

the method comprises the steps of placing a dismantling device (7) of an antifouling dismantling ship above a dam, placing a buoyancy tank (15) and a sludge carrier (2) on two sides of the dam, rotating a driving motor (30) of a first driving mechanism and a driving motor of a second driving mechanism, driving a transmission shaft (31) to rotate by the driving motor (30), then driving the buoyancy tank mechanism and the dismantling mechanism to slide along a rack (1) under the action of a gear III (34) and a rack (29), enabling the buoyancy tank mechanism and the dismantling mechanism to be accurately positioned, starting a second cylinder (14) to press the buoyancy tank (15) onto the water surface, floating the buoyancy tank (15) on the water surface, and supporting the buoyancy tank (15) and the sludge carrier (2) together;

then a first air cylinder (5) is started, a dismantling device (7) is pressed down onto the cofferdam, a cleaning device, a crushing device (8), a conveying device (9) and a spiral filter press are started at the same time, a purifier pipeline and a sludge pump are opened,

the cleaning device comprises 2 cleaning mechanisms (50) which are symmetrically arranged, and the cleaning mechanisms (50) comprise a plurality of cleaning plates (39); the two cleaning mechanisms rotate in opposite directions, the cleaning plates (39) scrape soil on the cofferdam into the stirring device (8), after the soil enters the stirring device (8), the turntable (40) of the stirring device (8) drives the stirring rod (41) to rotate, the stirring rod (41) stirs large soil blocks in the soil, meanwhile, the purifying agent entering the stirring device (8) is primarily mixed with the soil, the stirred soil enters the conveying device (9), the stirred soil enters the mixing pipe (16) under the pushing of the pushing screw of the conveying device (9), the soil and the purifying agent are further mixed, and then the soil enters the spiral filter press through the connecting pipe (3) under the action of the sludge pump;

in the spiral filter press, soil is extruded by a filter pressing spiral (28) to realize soil-water separation, water enters the water inflow cavity (24) through the water leakage hole (25) and is discharged out of the sludge carrying ship (2) through the water discharge pipe (26), and the soil after water removal is discharged into the sludge carrying cavity through the water discharge pipe (22) and is transported out of a water area.