A black and smelly water body dredging system and method

Abstract

The present invention discloses a black and odorous water body dredging system and method. The method comprises the following steps: setting an enclosure dredging unit in a river section to be dredged; determining the thickness of the surface sediment that is prone to black and odor through investigation, sampling and analysis, hydraulically flushing the surface sediment in the enclosure dredging unit, so that the surface black and odorous sediment is fully floated to form a mud-water mixture, and quickly extracting the mud-water mixture from the enclosure dredging unit, separating the non-polluted coarse sand particles in the mud-water mixture by physical precipitation, and then discharging the remaining mud-water mixture containing the black and odorous sediment into a sewage treatment facility. The system comprises an enclosure dredging unit, a flushing system, a sand-water separation system and a gravity drain pipe arranged in the water body to be dredged. The black and odorous water body dredging system and method provided by the present invention have strong dredging pertinence, convenient operation, small working space, flexible movement, low dredging cost, and can be well applied to the dredging project of the surface sediment that is prone to black and odorous sediment in small and medium-sized rivers.

Description

Technical Field

[0001] The present invention relates to the field of black and odorous water body treatment, and in particular to a black and odorous water body dredging system and method. Background Art

[0002] The purpose of desilting black and smelly water bodies is generally to remove pollutants from the riverbed mud and improve the river water environment.

[0003] At present, the common methods of dredging black and odorous water bodies include draining dredging and underwater dredging. According to the dredging machinery and equipment, draining dredging includes direct excavation and hydraulic flushing; underwater dredging includes grab dredging, pump suction dredging, cutter suction dredging and bucket wheel dredging.

[0004] The drainage and dredging works are large in scale and can usually only be carried out during the non-flood season. The construction period is subject to certain restrictions and will cause the black and smelly bottom mud to be exposed to the air, emitting odors. The construction efficiency is low and negative social effects will also be generated. Among the underwater dredging methods, the suction dredging and bucket wheel dredging are suitable for medium and large rivers with thick mud layers because of the large dredging equipment and large working space required. They cannot be flexibly operated in small and medium-sized rivers in cities. Grab bucket dredging is prone to causing floating mud to be missed and pollution to spread. While removing the silt, it severely disturbs the deep sediment and native soil, resulting in low environmental benefits. Pump suction dredging is prone to sucking out a large amount of sand particles, resulting in an increase in the workload of subsequent silt treatment.

[0005] Common dredging methods, whether it is drainage dredging or underwater dredging, will produce a large amount of mud or silt, including black and smelly bottom mud and deep sediment. These dredging methods will not only produce secondary pollution in the subsequent treatment process, but also occupy a large area of ​​​​sludge yard, the cost of sludge treatment and disposal is high, and the economic benefits are poor.

[0006] Studies have shown that compared with bottom sediment, the pollutant content and release concentration in surface sediment are usually higher, and the impact on water quality is also greater. Moreover, under disturbed water conditions, surface floating mud is easy to resuspend, causing more pollutants to be released into the water. The existing common dredging methods tend to remove black and smelly sediment and non-polluting sand particles together, and the dredging is poorly targeted, costly but inefficient.

[0007] Therefore, in the practice of dredging small and medium-sized rivers, it is of great significance to explore a low-cost, high-efficiency, and targeted dredging system that can remove surface sludge that is prone to causing black and smelly sediments and avoid the spread of pollution. Summary of the invention

[0008] The purpose of the present invention is to provide a black and smelly water body dredging system and method, which has strong dredging pertinence, is easy to operate, has a small working space, is flexible to move, and can be well applied to dredging projects of small and medium-sized river surface areas that are prone to black and smelly bottom mud.

[0009] To achieve the above-mentioned purpose, the present invention provides a method for dredging black and smelly water bodies, comprising the following steps: setting a closed enclosure dredging unit with a top higher than the water surface in the water body section to be dredged; hydraulically flushing the bottom mud of the water body in the enclosure dredging unit to make the black and smelly bottom mud with a relatively light specific gravity fully float to form a mud-water mixture; quickly extracting the mud-water mixture from the enclosure dredging unit, separating the unpolluted coarse sand particles therein by physical sedimentation, and then discharging the remaining mud-water mixture containing the black and smelly bottom mud with a relatively light specific gravity.

[0010] As a further improvement of the present invention, the mud-water mixture containing the black and smelly sludge is discharged into a municipal sewage network or a sewage treatment facility.

[0011] As a further improvement of the present invention, the thickness of the black and smelly sludge is determined through investigation, sampling and analysis; when hydraulic flushing is performed, only the surface sludge of the specified thickness is flushed to avoid disturbing the deep sediment.

[0012] As a further improvement of the present invention, the water body section to be dredged is divided into at least two parts, each of which is provided with an enclosure and dredging unit; when hydraulic flushing is performed, the water level in the enclosure and dredging unit is controlled so that the water level height is not higher than 50 cm.

[0013] As a further improvement of the present invention, when setting up the enclosure and dredging unit, the enclosure and dredging unit is constructed along the edge of one side of the water body, with the edge of the water body serving as a closed wall; the width of the enclosure and dredging unit is slightly smaller than the width of the water body, with a water passage left between the two.

[0014] To achieve the above objectives, the present invention also provides a black and smelly water body dredging system, comprising an enclosure dredging unit arranged in the water body to be dredged, a flushing system for conveying flushing water, and a sand-water separation system connected to the enclosure dredging unit.

[0015] As a further improvement of the present invention, the flushing system includes a water supply pipe, a high-pressure water pump, a flushing pipe and a flushing water gun connected in sequence along the water flow direction; the input end of the water supply pipe is located on the outside of the enclosure and dredging unit, and the flushing water gun is located on the inside of the enclosure and dredging unit.

[0016] As a further improvement of the present invention, the enclosure and dredging unit is a temporarily constructed cofferdam, which includes a main frame and a waterproof fabric, and the waterproof fabric is surrounded by the outside of the main frame; the main frame is a scaffolding or a cofferdam wall formed by stacking multiple sandbags.

[0017] As a further improvement of the present invention, the sand-water separation system includes a water pipe, a mud pump and a grit chamber connected in sequence; the input end of the water pipe is connected to the enclosure and dredging unit; the grit chamber is a rectangular tank body, and the water outlet end of the grit chamber is higher than the water inlet end; a plurality of sand collecting hoppers are provided at the bottom of the grit chamber along the direction from the water inlet end to the water outlet end.

[0018] As a further improvement of the present invention, the water outlet of the sand-water separation system is connected to a gravity drainage pipe, and the drainage destination is a sewage pipe network or a sewage treatment plant or other sewage treatment facilities.

[0019] Beneficial Effects

[0020] Compared with the prior art, the black and odorous water body desilting system and method of the present invention have the following advantages:

[0021] 1. The enclosure dredging unit formed by setting up a cofferdam is beneficial to reduce the operation area during the hydraulic flushing step of the dredging process, so as to prevent the floating black and smelly sludge with a lighter specific gravity from spreading over a large area. The mud-water mixture can be quickly extracted with small equipment for treatment, reducing the exposure of the black and smelly sludge and the spread of irritating odor. The amount of mud-water mixture extracted from the enclosure dredging unit is small, which is convenient for rapid separation and treatment with a small sand-water separation system. The various components of the dredging system occupy a small area and are flexible and convenient to operate. It can be well applied to the dredging projects of black and smelly sludge in small and medium-sized water bodies such as ponds, ditches, canals, and rivers.

[0022] 2. A water passage is set on one side of the enclosure and dredging unit, which does not affect the water flow of the river, ensures the flood discharge function of the river, reduces the upstream thrust on the enclosure and dredging unit, and ensures the structural safety of the enclosure and dredging unit and the safety of the river water. At the same time, due to the narrow width of the water passage and the fast flow of the river here, when the water passage is flushed and dredged, the high-pressure water flow of the flushing water gun can be used to stir up the bottom silt. The silt is flushed by the hydraulic power of the narrow water passage and will soon be washed downstream, so that the bottom silt at the water passage can be cleared, reducing the construction cost.

[0023] 3. Use hydraulic scouring to suspend the black and smelly bottom mud with a lighter specific gravity and smaller particle size at the bottom of the water body, forming a mixture of water-black and smelly bottom mud-sand. After the sediment is precipitated by the sand-water separation system, the upper mud-water mixture contains black and smelly bottom mud with a lighter specific gravity and smaller particle size. This part of the mud-water mixture is discharged into the municipal sewage pipes along the river nearby, which can achieve targeted removal of black and smelly bottom mud, reduce the amount of sludge generated, and reduce the cost of sludge treatment.

[0024] 4. Since the invention is used to clean the black and smelly bottom mud at the bottom of a small area of ​​water, the system components are small in size, occupy a small area, have a small working space, and are flexible to move and easy to load and unload. The enclosure dredging unit is easy to assemble and disassemble, and it can be gradually advanced along the dredging river section to achieve dredging of the entire river section.

[0025] 5. When hydraulic flushing is carried out, the water level in the enclosure and dredging unit should be controlled so that the water level is no higher than 50 cm. This can reduce the flushing resistance and allow the black and smelly sludge at the bottom to float fully when flushed, thus achieving a better flushing effect.

[0026] 6. Construction workers can operate the flushing water gun in the enclosure and dredging unit to flush the black and smelly sludge in the enclosure and dredging unit, which is easy to operate.

[0027] 7. The sand-water separation system is a grit chamber, which separates the non-polluted sand particles in the mud-water mixture through physical sedimentation. It does not require additional energy, has a simple structure, and has a good separation effect. The water outlet of the grit chamber is higher than the water inlet, which is convenient for the sedimentation of sand particles. There are several sand collecting hoppers at the bottom of the grit chamber along the direction from the water inlet to the water outlet, which is convenient for cleaning the settled sand particles.

[0028] 8. This system makes full use of the existing sewage pipe network to receive external sewage, reduces the pollution of the river to the downstream river, and is environmentally friendly. The precipitated mud and sand are simply washed back to fill the river, and the clean mud and sand are used to cover the riverbed, which reduces the amount of sludge treatment and disposal, and reduces the release of pollutants in the deep sediment of the riverbed.

[0029] The present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, which are used to illustrate embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a top view of the black and smelly water body desilting system;

[0032] Figure 2 It is a horizontal side view of the black and smelly water dredging system. DETAILED DESCRIPTION

[0033] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0034] Example

[0035] The specific embodiments of the present invention are as follows Figure 1 to Figure 2 As shown, a black and smelly water body dredging system includes an enclosure dredging unit 1 arranged in the water body to be dredged, a flushing system 2 for conveying flushing water, and a sand-water separation system 3 connected to the enclosure dredging unit 1.

[0036] The flushing system 2 includes a water supply pipe 21, a high-pressure water pump 22, a flushing pipe 23 and a flushing water gun 24 which are sequentially connected along the water flow direction, wherein the flushing pipe 23 is a hose. The input end of the water supply pipe 21 is located outside the enclosure desilting unit 1, and the flushing water gun 24 is located inside the enclosure desilting unit 1.

[0037] The enclosure and dredging unit 1 is a temporary cofferdam, which includes a main frame 11 and a waterproof fabric 12, and the waterproof fabric 12 covers the outside of the main frame 11. The main frame 11 can be a cofferdam wall composed of multiple stacked sandbags; the main frame 11 can also be built with a scaffolding, which is connected by steel pipes and fasteners. The waterproof fabric 12 can be a waterproof cloth. The enclosure and dredging unit 1 is built along the edge of one side of the water body, with the edge of the water body as a closed wall.

[0038] The width of the enclosure and desilting unit 1 is slightly smaller than the width of the water body to be desilted, and a water passage 4 is left between the two.

[0039] The sand-water separation system 3 includes a water pipe 33, a mud pump 34 and a grit chamber 31 which are connected in sequence. The input end of the water pipe 33 is located on the inner side of the enclosure dredging unit 1. The water inlet end of the grit chamber 31 is connected to the output end of the water pipe 33 through the mud pump 34. The grit chamber 31 is a rectangular tank body, which is assembled by splicing simple materials (stainless steel, plexiglass, etc.). The water outlet end of the grit chamber 31 is higher than the water inlet end, which is convenient for the sedimentation of sand particles. A plurality of sand collecting hoppers 32 are provided at the bottom of the grit chamber 31 along the direction from the water inlet end to the water outlet end, which is convenient for cleaning the settled sand particles.

[0040] The water outlet of the sand settling tank 31 of the sand-water separation system 3 is connected with a gravity drainage pipe 5. The gravity drainage pipe 5 is connected with sewage treatment facilities such as a sewage pipe network or a sewage treatment station.

[0041] This embodiment takes a river as the main body of dredging to illustrate that the method for dredging black and smelly water in a river includes the following steps:

[0042] Before dredging, a sediment survey should be conducted to determine the shape and characteristics of the riverbed through measurement, and to determine the sediment thickness, the stratified distribution characteristics of pollutants in the sediment, the particle size and density of the black and smelly sediment through sediment sampling and analysis, so as to confirm the distribution of the surface black and smelly sediment and deep sediment. The results of the sediment survey can provide theoretical support for the targeted removal of the surface black and smelly sediment during the subsequent dredging operation. Among them, the thickness and texture of the sediment are related to the parameters such as the dredging thickness, the water pressure, flow rate, and scouring time of hydraulic scouring. The thicker the sediment thickness and the firmer the texture, the greater the water pressure and flow rate should be during hydraulic scouring, and the longer the scouring time should be; if the sediment thickness is smaller and the texture is looser, the hydraulic scouring water pressure and flow rate will be smaller, and the scouring time will be shorter. The size of the enclosure dredging unit 1, the width of the water channel 4, and the hydraulic scouring parameters need to be determined according to the river conditions and field tests.

[0043] After completing the preliminary sediment survey, the river section to be desilted is divided into at least two parts, and each part is built with a closed enclosure and desilting unit 1 whose top is higher than the current water level of the river. In this embodiment, the river width is 10-15m, and the area of ​​each temporary enclosure and desilting unit is set to 20-25 square meters, 1.5 meters high, and the water passage is 1 meter wide. Multiple enclosure and desilting units 1 can be built simultaneously along the river flow direction, or the next enclosure and desilting unit 1 can be built after each enclosure and desilting unit 1 is cleaned. When building the enclosure and desilting unit 1, first use sandbags to press one side of the waterproof fabric 12 to the river bottom, and then continue to pile up sandbags until it is higher than the river water level to form the main frame 11 of the enclosure and desilting unit 1. Pull up the other side of the waterproof fabric 12 and surround it along the outside of the sandbag to form a double-layer structure of inner sandbags and outer waterproof fabric 12, and finally form the enclosure and desilting unit 1. The purpose of pressing one side of the waterproof cloth to the river bottom first is to prevent water from entering the bottom of the enclosure and desilting unit 1. When the main frame 11 adopts scaffolding, the construction of the enclosure and dredging unit 1 is similar to that of sandbags. The size of the temporary enclosure and dredging unit is set according to the construction conditions. On the premise of reserving enough construction space, the scope of the enclosure and dredging unit is minimized as much as possible to ensure the dredging effect while avoiding problems such as pollution diffusion and incomplete mud collection caused by excessive construction area. According to the terrain conditions of the river channel, the temporary enclosure and dredging unit 1 can be regular or irregular in shape.

[0044] When setting up the enclosure and dredging unit 1, a water passage 4 is left between one side of each enclosure and dredging unit 1 and the river channel along the river channel to ensure the water passing or flood discharge function of the river channel, reduce the upstream thrust on the enclosure and dredging unit 1, and ensure the structural safety of the enclosure and dredging unit 1 and the water safety of the river channel. The width of the water passage 4 is determined according to the conditions of the river itself, and a water passage of sufficient width is ensured while ensuring that the dredging operation surface covers the width of the dredged river channel as much as possible. Since the width of the water passage is relatively narrow and the flow rate of the river water body is fast, when flushing and dredging the water passage 4, the high-pressure water flow of the flushing water gun 24 can be directly used to stir up the bottom silt. The silt is hydraulically transported by the rapid current in the narrow water passage and will soon be washed downstream, so that the bottom silt at the water passage 4 can be cleared.

[0045] After the enclosure and silt removal unit 1 is built, the input end of the water supply pipe 21 is placed in the water body outside the enclosure and silt removal unit 1. The construction personnel operate the flushing water gun 24 in the enclosure and silt removal unit 1 to hydraulically flush the mud layer at the bottom of the river channel, so that the light black and smelly bottom mud of this part floats up fully to form a mud-water mixture. The water pressure, flow rate and flushing time of the flushing water gun 24 are controlled to carry up all the black and smelly bottom mud as much as possible, while trying to avoid disturbing the deep mud at the bottom of the river channel and reduce the mixing of the deep mud and the water body.

[0046] The water pipe 33, under the action of the mud pump 34, extracts the mud-water mixture from the enclosure silt removal unit 1 and transports it to the sand settling tank 31. When hydraulic flushing is performed, the water level in the enclosure silt removal unit is controlled by the mud pump 34 to avoid overflow of the water body in the enclosure silt removal unit 1. It is best to keep the water level no higher than 50 cm. In order to prevent the floating silt in the enclosure silt removal unit from settling again, the area flushed by the flushing water gun 24 should be kept close to the input end of the water pipe 33 so that the flushed mud-water mixture can be pumped away in time. The hydraulic flushing and the transportation of the mud-water mixture to the sand-water separation system 3 are carried out simultaneously. Stop flushing when there is no obvious black mud mixed in the water body of the temporary enclosure silt removal unit.

[0047] In this embodiment, the size of the grit chamber 31 is 5 meters in length, 1 meter in width, and 0.5 meters in height. After the mud-water mixture is precipitated in the grit chamber 31, the heavier silt is separated from the mud-water mixture due to physical sedimentation. The upper mud-water mixture containing lighter silt needs to be treated separately. In this embodiment, it is discharged into the sewage network along the river bank through the gravity drain pipe 5, thereby effectively removing the black and smelly bottom sludge on the surface of the black and smelly water body. The heavier silt can be backfilled into the river after a simple flushing, minimizing the cost of sludge treatment and disposal. When there is no obvious black mud mixed in the water body in the temporary enclosure dredging unit, the dredging work can be ended.

[0048] Regarding the construction method, if the river width is small, full-width construction is preferred, that is, only one row of enclosure and dredging units is built in the construction section, and dredging is carried out in sequence, but a water passage is left. If the river width is large, the flow is large, and the flood discharge requirements are high, half-width construction can be considered. Half-width construction is divided into two halves, left and right, with two rows of enclosure and dredging units built on the left and right. After dredging on one side is completed, dredging on the other side will be carried out.

[0049] The dredging method adopted in this technical solution has certain similarities with the hydraulic flushing and excavation method for draining and dredging, but the two have essential differences in three aspects, namely, design ideas, river drainage, mud sedimentation, and sludge treatment, which lead to differences in cost and benefit. The design ideas of this solution are significantly different from the traditional dredging method. The mud-water mixture containing the surface black and smelly bottom mud is pumped away by the mixing effect of the water body. While removing the black and smelly bottom mud in a targeted manner, it provides hydraulic conditions for the subsequent drainage of the black and smelly bottom mud. Hydraulic flushing and excavation is carried out under the premise of draining the river water body. The high-pressure water gun of the hydraulic flushing and excavation unit is used to flush the bottom mud, disturbing the bottom mud into mud. The flowing mud is collected in the low-lying area set in advance, sucked by the mud pump and transported by pipeline, and the mud is transported to the yard or slurry collection pool on the shore. This method has a large amount of engineering, and the construction period is affected by the weather. The sludge re-precipitation effect in the generated mud is obvious, and the subsequent sludge treatment cost is high. Compared with the hydraulic flushing method, this black and smelly water body dredging method mainly removes the surface black and smelly sludge, discharges the black and smelly sludge with lighter specific gravity into the sewage pipe network along the river, and backfills the separated silt into the river after simple flushing. This dredging method does not need to drain the river water body, has strong targeted dredging and low sludge treatment cost, and can be well applied to the dredging projects of small and medium-sized rivers with surface black and smelly sludge that is easy to cause.

[0050] The present invention has been described above in conjunction with the best embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations based on the essence of the present invention.

Claims

1. A method for desilting a black and smelly water body, characterized in that The method comprises the following steps: setting a closed enclosure dredging unit (1) with a top higher than the water surface in a water body section to be dredged; hydraulically flushing the bottom mud of the water body in the enclosure dredging unit (1) to fully float the black and smelly bottom mud with a relatively light specific gravity to form a mud-water mixture; rapidly extracting the mud-water mixture from the enclosure dredging unit (1), separating the non-polluted sand particles therein by physical sedimentation, and then discharging the remaining mud-water mixture containing the black and smelly bottom mud; determining the thickness of the black and smelly bottom mud by investigation, sampling and analysis; during hydraulic flushing, only flushing the bottom mud of a specified thickness to avoid disturbing the deep sediment; dividing the water body section to be dredged into at least two parts, Each of the parts is provided with an enclosure and dredging unit (1); when hydraulic flushing is performed, the water level in the enclosure and dredging unit (1) is controlled so that the water level is not higher than 50 cm; when the enclosure and dredging unit (1) is provided, the enclosure and dredging unit (1) is constructed along the edge of one side of the water body, with the edge of the water body serving as a closed wall; the width of the enclosure and dredging unit (1) is slightly smaller than the width of the water body, with a water passage (4) left between the two; when flushing and dredging the water passage (4), the bottom silt is stirred up with a high-pressure water flow, and the silt is quickly flushed downstream by the hydraulic flushing of the narrow water passage, so that the bottom silt at the water passage can be cleared.

2. A method for desilting a black and smelly water body according to claim 1, characterized in that: The mud-water mixture containing the black and smelly sludge is discharged into a sewage treatment facility.

3. A black and odorous water body desilting system using the black and odorous water body desilting method according to claim 1, characterized in that: It comprises an enclosure and desilting unit (1) arranged in a water body to be desilted, a flushing system (2) for conveying flushing water, and a sand-water separation system (3) connected to the enclosure and desilting unit (1).

4. A black and smelly water body desilting system according to claim 3, characterized in that: The flushing system (2) comprises a water supply pipe (21), a high-pressure water pump (22), a flushing pipe (23) and a flushing water gun (24) which are sequentially connected along the water flow direction; the input end of the water supply pipe (21) is located outside the enclosure and desilting unit (1), and the flushing water gun (24) is located inside the enclosure and desilting unit (1).

5. A black and smelly water body desilting system according to claim 3, characterized in that: The enclosure and dredging unit (1) is a temporarily constructed cofferdam, which comprises a main frame (11) and a waterproof fabric (12), wherein the waterproof fabric (12) surrounds the outside of the main frame (11); the main frame (11) is a scaffolding or a cofferdam wall formed by stacking a plurality of sandbags.

6. A black and smelly water body desilting system according to claim 3, characterized in that: The sand-water separation system (3) comprises a water pipe (33), a mud pump (34) and a grit chamber (31) which are connected in sequence; the input end of the water pipe (33) is connected to the enclosure and desilting unit (1); the grit chamber (31) is a rectangular tank body, and the water outlet end of the grit chamber (31) is higher than the water inlet end; and a plurality of sand collecting hoppers (32) are provided at the bottom of the grit chamber (31) along the direction from the water inlet end to the water outlet end.

7. A black and smelly water body desilting system according to claim 3, characterized in that: The water outlet of the sand-water separation system (3) is connected to a gravity drainage pipe (5) for connecting to a municipal sewage network or a sewage treatment facility.

Images