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What Does Dredging A Lake Mean?

2019-11-19 10:25:44 Jason 7008

What Does Dredging A Lake Mean?

At present, lake dredging has expanded from the traditional water conservancy project goal of improving lake flood control, drainage and irrigation capacity to the ecological water conservancy goal. That is to say, in many lake dredging projects, the goal of reducing lake endogenous pollution is The improvement of lake water quality provides the engineering purpose of protection.

Historically, the dredging works of lakes were mostly based on artificial physical labor, while large dredging equipment and dredging vessels were basically built for large-scale dredging of ports, waterways or large rivers, and could not enter small and medium-sized schools. The construction of the lake, so the small and medium river dredging project generally does not have very suitable dredging equipment for construction. Another problem associated with dredging in lakes is the handling of sludge. In the past, there were widespread winter operations of “digging river mud” in the lake, and there was a habit of using the excavated river mud as a fertilizer after composting. This habit naturally solved the problem of the fatness of the mud. Nowadays, due to the development of enterprises, some lakes have been polluted by industrial sewage, and the changes in lifestyle have caused some small industrial wastes and domestic garbage to be disposed of in lakes. For these reasons, some river muds become “sludge” and their properties are no longer suitable for direct return to the field or for use as fertilizer after manure. On the other hand, the use of chemical fertilizers in agricultural production is becoming more and more common, and the fertilizers originally made from river mud have gradually lost their demand.

1. Common Lake Dredging Technology

Most of the current lake dredging projects have the purpose of improving water quality, so they are still in the scope of “environmental dredging”. The current dredging project has the characteristics of systematic construction, and preliminary sediment survey should be conducted before dredging. By measuring the shape characteristics of the lake bed, the characteristics of the pollutants in the sediment and whether it exceeds the environmental quality standards are determined through sediment sampling analysis. Small and medium-sized lakes, especially lakes, are too small. These early-stage work can easily be ignored, but in fact, some simple preliminary work will be helpful for the smooth implementation of the entire project and the expected results. On the basis of the preliminary work, according to the quantity and scope of sedimentation, the nature of the sediment and the surrounding conditions, the technological schemes including the main engineering links such as dredging, transportation, silt disposal and tail water treatment are determined, and the dredging technology and construction are selected according to local conditions. Equipment, properly handle the sludge generated by dredging and prevent secondary pollution.

Due to the numerous dredging projects in international ports, waterways, inland rivers and lakes in recent years, the dredging and dredging technology has been greatly developed and the equipment capacity has been greatly improved. However, special vessels and equipment capable of entering small and medium-sized lakes and lakes are not common. The most commonly used small and medium lake dredging technology can be classified

Common lake dredging technology - Leader Dredger.jpg

1.1 Drain And Dredging

For lakes with low flow without flood control, drainage and shipping functions, draining and dredging refers to the method of dredging by dry excavation or hydraulic excavation by constructing temporary cofferdams in the lake construction section. After draining, it can be divided into two processes: dry digging and dredging and hydraulic dredging and dredging.

a. Dry excavation and dredging: 

After the water in the working area is drained, excavators are used for excavation in most cases. The excavated silt is directly transported by the muck or placed on the shore for temporary stacking. If there is a certain width of the river pond, there is a distance between the construction area and the storage pile point, and there is a need for transfer equipment to transport the sludge to the storage stacking point on the shore. Generally, the squeeze mud pump is used, that is, the concrete pump is used to transport the flow plastic sludge, and the conveying distance can reach 200-300 m. There are also engineering examples for the short-distance transportation by the belt conveyor. The advantages of dry excavation and dredging are thorough dredging, easy to ensure quality and low requirements for equipment and technology; the resulting sludge has low moisture content and is easy to be processed.

b. Hydraulic dredging and dredging: 

The high-pressure water gun of the hydraulic punching unit is used to wash the bottom mud, and the bottom mud is disturbed into mud. The flowing mud is collected into the low-lying area set in advance, sucked by the mud pump, transported by the pipeline, and the mud is transported to the shore. Inside the yard or in the sump pool. Hydraulic excavation has the advantages of simple machine, convenient transportation and low construction cost. However, the mud concentration formed by this method is low, which increases the difficulty for subsequent treatment and the construction environment is also relatively bad.

In general, draining and dredging has the advantages of intuitive construction conditions and easy quality assurance, and it is also easy to deal with large and complex garbage in dredged objects. The disadvantage is that the cost of temporary cofferdam construction is increased due to the drainage of water in the lake. At the same time, many lakes can only be constructed during non-flood periods, the construction period is limited, the construction process is susceptible to weather, and it is easy to be on the lake side. Slopes and ecosystems have an impact.

1.2 Underwater Dredging

Underwater dredging generally refers to the installation of dredging equipment on the ship. The dredging vessel is used as a construction platform to operate the dredging equipment on the water surface to excavate the sludge and transport it to the onshore yard through the pipeline transportation system. There are several ways to dredge underwater.

a. Grab-type dredging:

Using the grab-type dredger to excavate the river bottom mud, through the grab-type dredger forearm grab into the river bottom, using hydraulic pressure to drive the grab into the bottom mud and catch the underwater After the silt, then the cyclone is raised and the grab is opened, and the silt is directly discharged into the barge boat anchored on the side of the dredger, excavating, turning, and unloading the mud. The cleared silt is transported to the silt yard by a barge boat. The mud dumping from the barge vessel still requires the use of a shore grab to move the silt from the barge to the silt yard on the shore.

Grab-type dredging is suitable for small and medium-sized lakes with large mud layer thickness and many obstacles in the construction area. It is mostly used to expand the dredging project of the lake flood section. The grab dredger is flexible and maneuverable, and is not affected by obstacles such as garbage and stones in the lake. It is suitable for excavating earthwork with hard earth or entraining more impurity garbage; and the construction process is simple, the equipment is easy to organize, and the project investment is relatively low. The construction process is not affected by the weather. However, the grab dredger is less sensitive to the extremely weak sediment, and it is easy to produce the situation that the hard soil of the lower part of the river bed is dug, which causes a large amount of surface sediment, especially floating mud. The surface floating mud is stirred back and returned to the water body. The sludge removal rate of grab dredging can only reach about 30%, and the grab-type dredging is prone to the omission of floating mud and strong disturbance of the sediment. It is often impossible to reach the original dredging project with the aim of improving water quality. purpose.

b. Pumping dredging (Jet Suction Dredger): 

Also known as suction-type dredging, it is equipped with a water gun and a suction pump that are hydraulically dig in a cylindrical cover. The water is sprayed into the mud and the mud is passed through another The mud pump on the side sucks out the mud and sends it to the yard on the shore through the pipeline. The whole set of equipment is equipped on the vessel and moved to remove it. Another pumping method is a method of sucking and discharging sludge by using compressed air as a power. The cylindrical pump has an open pump cylinder that sinks into the bottom under the action of gravity, and after being trapped in the bottom mud, a negative pressure is applied in the pump cylinder, and the soft pressure is applied. The mud is sucked into the pump cylinder under the static pressure of the water and the vacuum of the pump cylinder. The sludge in the cylinder is then pressed into the sludge discharge pipe by compressed air, and the sludge is transported to the mud carrier or the yard on the shore through the mud discharge valve and the mud transfer pipe.

Pumping dredging (Jet Suction Dredger).jpg

The pumping dredging equipment is relatively simple and can be equipped with small and medium-sized vessels and equipment, suitable for small lake construction. Under normal circumstances, it is easy to suck out a large amount of river water, resulting in an increase in the workload of subsequent mud treatment. At the same time, the composition of garbage in lakes in China is complex and varies in size, which is likely to cause blockage of suction ports.

c. Cutter suction dredging:

Cutter suction dredging is mainly done by a cutter suction dredger. The cutter suction dredger consists of a floating body, a reaming cutter, an upper suction pipe, a lower suction pipe pump, and power. It uses the rotary motion of the bridge leading edge reamer installed in front of the ship to cut and stir the riverbed sediment, and mixes the mud and water to form a mud. The suction vacuum generated by the centrifugal pump on the ship makes the mud enter along the suction pipe. The suction end of the mud pump is transported through a fully enclosed pipeline (after the row distance exceeds the rated row of the dredger, and the relay pump is pressurized in the middle) to the yard. 

Cutter suction dredging.jpg

The cutter suction dredging is suitable for dredging of medium and large lakes with large mud layers. Cutter suction dredging is a process of integrated excavation, transportation and blowing. It uses purely closed pipeline to transport mud, which will not cause mud to be scattered or leaked. It will not affect the navigation of the lake during the dredging process, and the construction will not be affected by the weather. Impact, while using GPS and echo detectors for construction control, can improve construction accuracy. Cutter suction dredging is easy to cause the diffusion of pollutants in the sediment due to the open excavation using the spiral slice cutter, and there is also a serious back siltation phenomenon. The concentration of the blown mud is too low, resulting in an increase in the volume of the mud, which will increase the footprint of the silt yard.

d. Bucket wheel dredging: 

The underwater mud is excavated by a special bucket wheel excavator mounted on a bucket wheel dredger. The excavated sludge is sucked through the high-power mud pump on the dredger and enters the mud pipeline. The closed pipeline is transported to the designated dumping area. The bucket wheel dredger and bucket wheel are shown in Figure 2. Bucket wheel dredging is generally suitable for excavating medium and large lakes, lakes and reservoirs with thick mud layers and large engineering volume. It is a common method for project dredging. The dredging process will not affect the navigation of the lake, the construction is not affected by the weather, and the construction accuracy is high. However, the bucket wheel dredging will generate a large amount of pollutants in the dredging project, and the situation of dredging and silting will be serious. The silt removal rate is about 50%. The dredging is not thorough enough, which is likely to cause large-scale water pollution.

Bucket wheel dredging.jpg

1.3 Environmental dredging

Environmental dredging contains two aspects. On the one hand, it refers to the dredging project with the aim of improving water quality, on the other hand, it can avoid the impact on the water environment as much as possible during the dredging process. The characteristics of environmental dredging are:

1. The dredging equipment should have high positioning accuracy and excavation precision to prevent leakage and over-excavation, and not to damage the original soil;

2. In the process of dredging, prevent disturbance and diffusion, not cause secondary pollution of water body, reduce turbidity of water body, control noise of construction machinery, and not interfere with normal life of residents;

3. Silt dumping should be away from residential areas to prevent secondary pollution caused by transportation on the way.

The key and difficult point of environmental dredging is how to ensure effective dredging depth and location, and effective secondary pollution prevention. In order to achieve this goal, special dredging equipment is generally used. If using conventional dredging equipment, it must be correspondingly Improve. Special equipment includes Japanese screw dredging equipment and closed rotary bucket wheel dredging equipment. These two devices can block water from invading the soil during dredging, so they can be dred at a high concentration with little contamination and diffusion, and hardly pollute the surrounding waters. The pneumatic pump dredger developed by Italy is used to dredge the underwater polluted sediment. It uses hydrostatic pressure and compressed air to remove contaminated sediment. The dredging mass fraction of this device is high, up to 70%, without disturbing the bottom of the lake, during the dredging process. Will not pollute the surrounding waters. The environmental dredging equipment currently used in China is mostly environmentally modified on some dredgers, and equipped with advanced high-precision positioning and monitoring systems to improve dredging accuracy and reduce secondary pollution during dredging. Meet the requirements of environmental dredging.

Environmentally friendly cutter suction dredging is currently the most commonly used method of environmental dredging. It is suitable for large, medium and small lakes, lakes and reservoirs with large engineering volume, and is mostly used for environmental dredging projects of lakes, lakes and reservoirs. Environmentally friendly cutter suction dredging is carried out by using an environmentally friendly cutter suction dredging vessel. The environmentally-friendly cutter suction dredging vessel is equipped with a special environmental protection cutter head. During the dredging process, the closed-type low-disturbing dredging is carried out by using the environmentally-friendly cutter head. The excavated sludge is sucked in and passed through the high-power mud pump on the dredger. The mud pipeline is transported to the designated dumping area via a fully enclosed pipeline. Environmentally friendly dredging vessel and special environmental protection cutter head.

The environmentally-friendly cutter suction dredging vessel is equipped with a special environmental protection cutter head to prevent leakage and spread of contaminated sludge. It can dredge thin polluted sediment and less disturbance to the sediment, avoiding the spread of contaminated sludge and escaping. The mud removal rate can reach more than 95%; the dredging concentration is high, the silt mud mass fraction is over 70%, and the thickness of one dredged mud can be 20-110 cm. At the same time, the environmentally-friendly cutter suction dredger has high-precision positioning technology and on-site monitoring system. Through simulation animation, the excavation trajectory of dredging equipment can be visually observed;

What Dose Dredging A Lake Mean (6).jpg

2 Treatment And Disposal Technology Of Lake Silt

The dredging of lakes will inevitably produce a large amount of silt. These silts generally have high water content and low strength. Some of the sludge may contain toxic and harmful substances. These toxic and harmful substances are easily leached after being washed by rain, thus causing secondary pollution to the surrounding water environment. Therefore, it is necessary to carry out reasonable treatment and disposal of the sludge produced after dredging. The sludge treatment method is affected by the basic physical and chemical properties of the sludge itself. These basic properties mainly include the initial moisture content of the sludge (water to dry soil mass ratio, the same below), clay content, organic matter content, clay mineral type and pollution. Type of substance and degree of pollution. In the actual sludge treatment project, an appropriate treatment plan can be selected according to the basic properties of the sludge to be treated and the processing conditions possessed.

Throughout the domestic and foreign sludge treatment and disposal technology, the classification can be carried out according to different classification criteria. In the actual sludge treatment project, the appropriate treatment plan can be selected according to the basic properties of the sludge to be treated and the processing conditions it has. .

Cutter Suction Dredger | Leader Dredger

2.1 Treatment of non-polluted sludge and contaminated sludge

Whether the sludge is polluted and the types of pollutants are different, the corresponding treatment methods are not the same. The sludge produced in some water conservancy projects is basically free of pollutants or pollutants lower than the relevant standards, such as the Huai'an Baima Lake of the South-to-North Water Diversion Project. The dredged sludge has no heavy metal pollution, and the content of nutrients such as nitrogen and phosphorus is also low. For such non-polluting or lightly polluted silt, it can be resourced. This type of sludge is mainly produced in industries with relatively backward industries. For sludge with pollutants exceeding the relevant standards, the pollution level should first be considered to reduce the pollution level to the relevant standards. For example, the passivation stabilization technology can be adopted for sludge with excessive heavy metal pollution. The choice of sludge treatment technology should also take into account the post-treatment uses, such as sludge with high nitrogen and phosphorus nutrient content. When the treated sludge is intended to be used as an embankment or ordinary fill, it is far away from the water source, and nitrogen and phosphorus cannot be used. When re-entering the water source to cause pollution, the problem of nitrogen and phosphorus pollution is generally no longer considered.

a. Yard treatment and in-situ treatment: 

The yard treatment method refers to the silt dredging and then transported to the designated silt yard for treatment. Most of the lake dredging in China uses a cutter suction dredger to cause water and mud in the silt. The volume ratio is more than 5 times, and the sludge itself has high clay content, poor water permeability and slow consolidation process. Therefore, how to achieve quick separation of mud and water, shorten the settlement time of sludge sedimentation, and accelerate the turnover or quick recovery of the yard. Ploughing is a key issue in the yard processing method. The local treatment method does not dredge the sediment, but directly covers the sediment under water or drains the overlying water and then dehydrates, solidifies or physically rinses, but the treatment method should also be selected according to the actual situation. For waters with large flow rates of shallow water or water, in-situ coverage should not be used. For large-area deep-water areas, it should not be treated with drainage.

b. Resource utilization and conventional disposal: 

Silt is essentially engineering waste. According to the principle of reduction, harmlessness and resource utilization of solid waste treatment, resource utilization should be considered as much as possible for sludge. Broadly speaking, as long as it can reuse the waste sludge, it is a resource utilization. For example, the use of silt bricks, ceramsite, solidification, drying, soiling and other methods are all sludge recycling technologies. The zone can return the sludge without heavy metal pollution but rich in nitrogen and phosphorus to the soil in the farmland. Or the silt can be used as agricultural land after being piled up in the shovel. Of course, if it can be naturally dried after stacking, it can be used as a park, green space or even municipal and construction land to meet the bearing capacity required for surface operations of people and light equipment. The utilization of sludge resource utilization technology is a treatment method commonly used in many developed countries in the world. For example, in Japan, the waste utilization rate of the entire civil engineering industry has increased from 58% in 1995 to 80% in 2000, and waste soil such as silt. The utilization rate has also reached 60% .

When the sludge contains certain special pollutants such as heavy metals or certain polymer refractory organic pollutants, it cannot be removed, and resource utilization will cause secondary pollution. At this time, it needs to be disposed of in one step, that is, measures are taken to reduce the biological toxicity and then safely landfilled, and the anti-seepage setting of the landfill should be done accordingly.

2.2 Passivation treatment technology for contaminated sludge

Heavy metal pollutants in lake silt in industrially developed areas often exceed the standard. Generally speaking, polluted sludge refers to heavy metal pollution in silt. For example, the heavy metal in the silt of Shanghai Suzhou River is more than 2 times higher than the local background value. For sludges with heavy metals exceeding the standard, passivation treatment technology can be used. The passivation treatment is based on the different active states of heavy metals in the sludge in different environments. The corresponding chemical materials are added to convert the unstable heavy metals in the sludge into stable heavy metals to reduce the activity of heavy metals and reduce pollution. purpose. At the same time, the chemical reaction of the added chemical materials and sludge will produce some substances that are physically wrapped with heavy metals, which can reduce the leaching of heavy metals, thereby further reducing the release and harm of heavy metals. After the leaching of heavy metals after passivation is less than the relevant standard requirements, the sludge can be disposed of in low-lying land or as a filling material.

2.3 yard silt disposal technology

In the dredging project, a silt yard is usually set up. The yard treatment technology starts from the initial stage of dredging, adopts a series of treatment measures to quickly promote sedimentation and rapid consolidation, and combines surface treatment technology to turn the silt yard into use or reach Rapid re-cultivation of silt yards.

The purpose of yard turnover technology is to reduce the number of yards and land occupation. The surface treatment technology of the yard is to provide an operation platform for subsequent construction, and the rapid re-cultivation technology of the yard is to achieve rapid restoration of sludge yards through the combination of series technologies. For cultivated land.

a. The yard uses technology. 

The yard turnover technology refers to the rapid treatment of the sludge in the yard through technical measures, and then re-blown and use after emptying, thus repeatedly achieving the purpose of recycling the yard. The yard turnover technology has changed the previous large-field and large-capacity design methods, and proposed the concept of small yards and efficient turnover, which is especially suitable for the eastern regions where land resources are scarce. The design of the yard turnover technology mainly considers the total amount of sludge to be treated, the capacity of the yard, the turnover period and the number of turnovers. The technology can usually be combined with curing or drying technology to use solidified sludge or dried sludge in situ. The yard is cofferdam, and the sludge in the yard can also be quickly utilized.

b. Yard surface treatment technology. 

The initial moisture content of the dredged mud is generally above 80%, while the sludge particles are extremely fine and the clay content is above 20%, which makes the mud deposit in the yard very slow and the consolidation time is very long. The sluice of the sludge is about 1.5 cm thick in the two or three years after the siltation, and the bottom is still a solid hard crust of about 20 cm. Above, it is very difficult to perform ordinary ground treatment. The surface treatment technology of the yard is to use the in-situ solidification treatment technology of the silt yard to artificially form a layer of artificial hard shell on the surface of the silt yard. The artificial hard shell has certain strength and rigidity to meet the construction requirements of small machinery. Drainage board laying and stacking construction can be carried out to facilitate further processing of the yard. The design of the artificial hard shell is the key to the surface treatment technology. It mainly considers the requirements of subsequent construction. Combined with the properties of the lower sludge, the strength parameters and design thickness of the hard shell are determined through experiments and simulations. The artificial hard shell technology is often combined with sludge. The curing technology combines to form a solid hard shell of solidified sludge, and it is also possible to form a lightweight artificial hard shell layer using polystyrene foam (EPS) particles.

c. Quick re-cultivation technology in the yard. 

The rapid re-cultivation technology of the yard mainly includes rapid separation technology of muddy water, artificial hard shell technology and rapid vacuum consolidation technology.

The quick separation technology of muddy water refers to the addition of a sedimentation material which improves the colloidal ion characteristics of clay particles in the process of blowing and silting, which promotes the rapid separation of solid soil particles and water and increases the density of sedimentation sludge. On the other hand, it is provided in the yard. The intercepting and adsorbing drainage membrane further increases the sedimentation speed of the dredged mud, and at the same time, the barrier can be used to increase the flow and change the flow state, thereby achieving the effect of rapid compaction of the dredged mud. The ventilating vacuum rapid consolidation technology is to insert a drainage board or a sand well in a silt yard through an artificial hard shell construction platform, and then lay a sand cushion layer on the hard shell layer, and the sand cushion layer and the drainage board overlap. The sealing membrane covering the impervious water is isolated from the atmosphere, and is pumped by a jet pump through a distributed pipeline embedded in the sand cushion with a water filter tube, and the process of discharging the pore water increases the effective stress, thereby increasing the heap. The strength of the field sludge reaches the goal of rapid consolidation. The combination of venting vacuum consolidation technology and conventional preloading technology can achieve better results.

For some silt yards, due to the deeper depth of the deposited silt, if the silt treatment of the entire silt yard is completed to meet the purpose of re-cultivation, the investment is large, and for the re-cultivation of the yard, the bearing capacity The requirements are relatively low, so re-cultivation techniques based on surface treatment of the yard are often used in deeper yards where silt is deposited. Through the in-situ solidification treatment technology of the silt yard, the silt surface layer (80-120 cm) sludge is solidified, and after the treatment is completed, the surface solidified soil is soiled to meet the requirements of plant cultivation.

2.4 Silt resource utilization technology

The various technologies, such as sludge solidification, drying, and soiling, which can be used to re-use waste sludge into resources, are all in the category of resource utilization of sludge. In addition, the sludge utilization technology also includes a heat treatment method for forming the sludge into bricks. The heat treatment method converts the sludge into building materials by heating and sintering, and can be divided into sintering and melting according to the difference of the principle. Sintering is performed by heating 800 to 1 200 ° C to dehydrate the sludge, decompose the organic components, and bond the particles. If the moisture content of the sludge is appropriate, it can be used to make bricks or cement. In the case of melting, the sludge is dehydrated by heating at a temperature of 1,200 to 1,500 ° C, the organic component is decomposed, and the inorganic mineral is melted, and the melt can be processed into a ceramsite by cooling treatment. The heat treatment technology has been relatively mature, and many scholars from abroad and abroad have conducted related research.

The heat treatment technology is characterized by high added value of the product, but the amount of sludge that can be treated by the heat treatment technology is very limited. For example, an ordinary brick factory can consume 50,000 m3 of sludge in one year, which cannot meet the current occurrence of drastic silt in China. The demand for processing, from the prospect of large-scale industrial treatment of sludge, solidification, drying, and soil-based sludge resource utilization technology is vital, and if combined with yard processing technology, it can show benefits.

3. Development direction of dredging and sludge treatment and disposal technology

With the development of society and the emphasis on ecological environment protection, more and more cities and lakes will be dredged and dredged. The large amount of sludge generated by dredging will occupy a large area of the yard, so the dredging technology and sludge treatment Technology has put forward new requirements.

a. High concentration in-situ environmental dredging method.

Due to the current environmentally friendly dredging method, the concentration of sludge is about 15% to 20%, the volume of water molecules is much larger than the volume of soil particles, and the volume of dredging mud is about 4 to 5 times that of particles. These high-content cement slurries often require large yards for placement, and many dredging projects are severely constrained by the problems of the yard site. High-concentration in-situ environmental dredging can reduce the capacity of mud in the process of dredging. In the middle conveying process, the moisture content of the mud can be reduced, and the sludge can be directly used as a soil material that can be used for filling. Therefore, in order to save land and reduce the cost of the entire dredging and sludge treatment, high-concentration in-situ environmental dredging technology has become a future development trend.

b. Stack silt rapid drainage technology.

Most of the silt in the inland rivers is currently piled up in the yard. The silt yard can be used for construction, landscape, and farmland utilization after being treated by foundation treatment to solve the problem of long-term swamp status. This foundation treatment process is the process of sludge consolidation and drainage. The silt has high clay content and poor water permeability, and has a long consolidation time under self-weight and low strength after self-weight consolidation. The problem of rapid drainage consolidation of silt has become an urgent problem to be solved. The vacuum preloading method and the preloading method used for soft clay foundations are often difficult to exert good effects on sludge [18-19]. The silt has a very high water content and is in a flowing state. The effective stress between the particles is very low. Under the high pressure vacuum state, the sludge particles will flow together with the interstitial water, so that the drainage plate is blocked and cannot be drained. How to solve the problem of clogging of the drainage system becomes the key to rapid drainage of sludge. The quick drainage technology of silt in the yard is to lay multi-layer and multi-row horizontal drainage channels in the silt, and the layer spacing and row spacing are all around 60-80 cm to form a high-density submerged drainage network. The network is sealed with the horizontal drain pipe sealed on the ground, and then connected to the jet drainage device to pump air to accelerate the drainage speed of the sludge. At present, this technology development and key issues are still in the early stages of exploration.

4. Conclusion

The dredging project of small and medium-sized lakes and lakes not only has the purpose of “salting” of traditional dredging, but also the purpose of solving the functions of drainage, flood control and irrigation. It also has the deep purpose of improving lake water quality, promoting ecosystem health and improving lake landscape. Therefore, from the preliminary work of dredging, program development, process selection, and project implementation, the characteristics of this “multi-purpose” dredging must be guaranteed.

The dredging project of small and medium-sized lakes and lakes is different from the port channel and the Dajiang River dredging project. It has the characteristics of small engineering volume, difficulty in the passage of large ships, and various types of garbage in the dredged objects. Simple dredging techniques based on this feature are often easy to adopt. Regardless of the technology used, the main goal of lake management, water quality improvement, should be a problem that must be considered in dredging methods and process selection. Depending on local conditions, considering the various conditions of the lake, it is a realistic choice to choose to drain and dredge when conditions permit. In the case of not being able to drain, an improved small pumping and cutter suction dredging vessel can be an option and a development direction for the dredging technology of small lakes.

The region is different from the coastal cities and has the advantages of low-lying areas and revolving land. Therefore, the idea of adapting to local conditions should also be highlighted in the treatment of sludge. The silt is reduced to land use after being piled up in a low-lying area, and the returning of the soil without heavy metal pollution, and the use as a river embankment reinforcement and road filling after simple treatment are the most suitable methods for the area.

Leader Dredger has invested a lot of research and development funds in the applicability of dredging engineering equipment in small and medium-sized lakes and strips 15 years ago. Now, he has achieved excellent results. Leader Dredger has become an excellent supplier of equipment for small and medium-sized lakes and dredging projects in China. Business. Professional dredging equipment and professional technical support have earned Leader Dredger a lot of honors.

The Main Purpose Of Dredging - Leader Dredger

The Main Purpose Of Dredging

(1)Remove nutrient-rich sediments

(2)Eradicate ingrained plants and debris

(3)Clear selection of areas such as beaches, docks and boating lanes

(4)Restore rainwater retention capacity and increase channel flow

(5)Handling contaminated sediments and wastewater

(6)Reset the life of the water

The benefits of dredging:

(1) Prevent flooding:

Silt, garbage, and sediments gradually accumulate over time as they pass through the water and the bottom of the water. When this happens, the water body becomes shallow and the water level is reduced, and when there are too many plants in the lake, it will not only affect the size of the lake or pond, but even floods.

When the rainy season comes, because the sediment is too much, the lake becomes very small, and a large amount of rainwater will overflow the flood. When the pond is cleaned using dredging equipment, the health of the water in the next few years can be guaranteed.

(2) Prevent blockage and increase channel flow

When a water area is used for industrial or recreational purposes, you need to consider the depth of the water to prevent the bottom of the vessel from being scratched when the water is too shallow.

(3) Protect animals

When the water level of the lake becomes shallow, this will seriously affect the survival of aquatic organisms. Water pollution can cause life-threatening disasters to animals.

(4) Environmental pollution

If the lake is left to be polluted and not effectively cleaned and dredged, the environment of the lake will become very bad. Such as unpleasant smells, unsightly colors, which can make plants near lakes and lakes unable to grow until they wither and eventually become swamps.

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