Ecological dredging construction method and treatment system for rivers and lakes

Abstract

The invention provides a river and lake ecological desilting construction method and a treatment system, and the method comprises the following steps: pretreating land sludge or water sludge for river and lake ecological desilting, then carrying out mud-water cascade separation and precipitation flocculation in a primary precipitation tank to obtain precipitated and flocculated sludge and supernatant, and carrying out secondary precipitation and flocculation in a secondary precipitation tank; the supernatant enters a sewage treatment system to be treated, precipitated and flocculated sludge discharged from land is subjected to mechanical filter pressing, dehydration and consolidation, the treated sludge is used for mine or pit backfilling and ecological restoration, and the sewage is returned to the primary sedimentation tank to be treated; or the settled and flocculated sludge discharged from the water is subjected to geotextile tube bag filling, dehydration and consolidation, the treated sludge is used for wetland construction and ecological restoration, and the sewage is returned to the primary settling pond for treatment. The invention has the beneficial effects of strong pertinence, good treatment effect, high productivity, no secondary pollution, safety, greenness and environmental protection aiming at sludge with different particle sizes and different working conditions.

Description

Technical Field

[0001] The present invention belongs to the field of ecological environment governance, and in particular relates to a river and lake ecological dredging construction method and a treatment system. Background Art

[0002] The dredging area is close to the ship channel, the levee and the wetlands on both sides of it. The construction site conditions are complex, and the requirements for water and underwater operations and channel safety are high. There is a lot of garbage mixed in the river and lake bottom mud, which is of various types and large sizes, making sorting and processing difficult. The amount of silt that needs to be dehydrated and consolidated is large, and the amount of tail water that needs to be purified is large. The technical quality standards for dry mud solidification, tail water purification and ecological restoration are high, and there are many problems such as spatial operations in restricted areas, operations near water and cross-site operations. Summary of the invention

[0003] In view of this, the present invention aims to propose a river and lake ecological dredging construction method and treatment system to solve at least one technical problem in the background technology.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A river and lake ecological dredging construction method comprises the following steps: pre-treating the sludge discharged from land or water during the river and lake ecological dredging, and then performing mud-water cascade separation and sedimentation and flocculation in a primary sedimentation tank to obtain sedimentation and flocculation sludge and supernatant, and the supernatant enters a sewage treatment system for treatment;

[0006] The sedimentation and flocculation sludge discharged from land is mechanically filtered, dehydrated and consolidated. The treated sludge is used for mine or pit backfill and ecological restoration, and the sewage is returned to the primary sedimentation tank for treatment;

[0007] Alternatively, the sedimentation and flocculation sludge discharged from the water is filled with geotube bags for dehydration and consolidation. The treated sludge is used for wetland construction and ecological restoration, and the sewage is returned to the primary sedimentation tank for treatment.

[0008] Furthermore, the mechanical filtration pressing, dehydration and consolidation of the sedimentation and flocculation sludge discharged from the land comprises the following steps: sampling in the primary sedimentation tank to obtain coarse sludge, medium coarse sludge, medium sludge and fine sludge;

[0009] The coarse sludge, medium coarse sludge, medium sludge and fine sludge are respectively concentrated and conditioned, and then filtered to obtain the treated sludge.

[0010] Further, the coarse sludge sludge is in the front area of ​​the primary sedimentation tank;

[0011] The medium-coarse sludge is located at the junction of the front and middle parts of the pumping tank;

[0012] The medium-sized sludge is in the middle area of ​​the primary sedimentation tank, and the fine-particle sludge is the sedimentation flocculation sludge in the terminal area of ​​the primary sedimentation tank;

[0013] On-site sampling was carried out from the front, middle and rear drainage areas of the pool, and the sludge particle size was measured in the laboratory to provide a basis for the subsequent selection of reagent ratios, concentration conditioning and filter press units;

[0014] The particle size of coarse sludge is above 20 microns;

[0015] The particle size of medium-coarse sludge is 16 to 20 microns;

[0016] The particle size of medium sludge is 14.27 microns to 16 microns;

[0017] The particle size of the micro-sludge is less than 14.27 microns.

[0018] Further, the coarse sludge concentration treatment and conditioning includes adding drugs to the coarse sludge in the concentration tank, concentrating, settling and flocculating the sludge, and then dehydrating and consolidating the coarse sludge through the belt filter press unit, during which agents are also added to promote the dehydration and consolidation of the belt filter press, the moisture content of the consolidated dry sludge is between 45% and 50%, and the thickness of the dry sludge cake is 25mm to 35mm;

[0019] And / or, sampling of medium and coarse sludge requires close cooperation between the test personnel and the filter press operator to find the approximate boundary layer of different particle sizes, switch the equipment combination at any time, adjust the reagent ratio of the concentration tank and the filter press unit in time, and change the sludge conveying direction in time;

[0020] And / or, the medium and coarse sludge concentration treatment and conditioning includes adding medicine to the medium and coarse sludge, concentrating, and settling and flocculating the sludge; and dehydrating and consolidating the sludge by a belt filter press unit and a plate and frame filter press unit, wherein the moisture content of the consolidated dry sludge is between 45% and 50%, and the thickness of the dry sludge cake is between 25mm and 35mm.

[0021] Furthermore, in step S2, the medium-grained sludge is concentrated and conditioned twice and then transported to a plate-and-frame filter press unit for treatment;

[0022] When the proportion of medium-sized sludge with a surface particle size close to 16 microns is greater than 50%, the sampling test frequency of the bottom sludge in the pool should be increased. The test personnel and the filter press operators should work closely together to find the approximate boundary layer of different particle sizes, switch the equipment combination at any time, and then adjust the reagent ratio of the concentration tank and the filter press unit in time, and change the conveying direction of the sludge in time, that is, select the filter press equipment according to the actual situation:

[0023] A portion of the bottom mud with a particle size close to 16 microns is filtered by a belt filter press after adjusting the reagent ratio and concentrating and conditioning twice in the concentration tank and transfer conditioning tank. At the same time, reagents are added again at the mud inlet end of the belt filter press to promote the mud-drug reaction, which can achieve a dry mud moisture content of 45% to 55% and a dry mud cake thickness of 20mm to 30mm.

[0024] For the other part of the bottom mud with a particle size of 14.27 microns ≤ <16 microns, after two concentration conditionings of concentration conditioning and transfer conditioning, the plate and frame filter press unit is used for filtration, which can achieve a moisture content of 45% to 50% for the consolidated dry mud and a dry mud cake thickness of 35mm to 40mm;

[0025] And / or, in step S2, the concentration treatment and conditioning of the particulate sludge includes sequentially performing a concentration tank, a transfer conditioning tank and a plate and frame filter press unit, while adjusting the reagent ratio, increasing the concentration and flocculation time of the mud and medicine in the concentration tank and the transfer conditioning tank, and increasing the filtration time of the plate and frame filter press unit. The moisture content of the dry mud can be controlled between 40% and 50%, and the mud cake thickness can reach 30 mm.

[0026] Further, the reagent added to the concentration tank of the belt filter press is: 0.5% PAC + 0.05% PAM or 0.09% PAC + 0.15% PAM;

[0027] And / or, the reagent added to the concentration tank of the plate and frame filter press is: 0.5% PAC + 0.05% PAM;

[0028] And / or, the reagent ratio of the dosing point of the belt filter press that is supplied multiple times is: 10% PAC + (0.1% to 0.2%) PAM;

[0029] And / or, the reagent ratio of the mud transfer conditioning tank used in conjunction with the plate and frame filter press is: 10% PAC + (0.1% to 0.2%) PAM.

[0030] Further, the precipitated flocculated sludge discharged from the water is dehydrated and consolidated in a geotube bag, including filling the precipitated flocculated sludge discharged from the water into the geotube bag, injecting flocculation drugs during filling, draining after filling, repeating the filling, drug addition, and draining steps until the geotube bag is filled, and then standing and consolidating;

[0031] The leachate tail water is collected and transported to the primary sedimentation tank.

[0032] Furthermore, geotextile tube bags filled with sedimentation and flocculation sludge from water discharge are laid beside rivers and lakes. When the bottom tube bag meets the filling and dehydration consolidation requirements, the upper tube bag is filled and dehydrated.

[0033] Before filling the upper layer of tube bags, use an inelastic rope to fix the tube bags of that layer;

[0034] And / or, the upper layer of tube bags should be laid in the middle of the two geotextile tube bags on the bottom layer that have been filled, and the gap between the two closely arranged tube bags on the bottom layer should be filled with geotextile mud;

[0035] The tube bag filling should be carried out in batches, and the filling height must be determined through pre-work tests. Several tube bags on the bottom layer should be carried out alternately at the same time. The operator should use a smooth wooden stick to regularly knock and vibrate the surface of the tube bag to speed up the sludge filtration and volume reduction process.

[0036] The geotubes are used to form an arc-shaped area beside the river and lake, and are connected to the shore. There are also several rectangular geotubes in the arc-shaped area.

[0037] A layer of geotextile tube bags and imitation wood piles are arranged outside the arc-shaped area, and enclosures are laid outside the wood piles to form a waterway for treatment between the enclosures, geotextile tube bags and imitation wood piles.

[0038] There are several algae collection platforms in the waterway to collect algae caused by eutrophication.

[0039] The treatment area of ​​this application is separated from other areas by fencing to prevent eutrophication in other areas from affecting the treatment area of ​​this application. In addition, the rectangular geotube bags provided in this application can divide the arc-shaped treatment area of ​​this application into several areas again, forming multiple ecological balances. If eutrophication occurs in one area, the impact on other areas is small and can be dealt with in a timely manner.

[0040] If the arc-shaped area is treated, the above operations can be repeated with the arc-shaped area as the shore to continue to treat the lake water in other areas, and gradually expand the treatment of the entire river and lake area and the surrounding water systems, which reduces the difficulty of treatment, and can be divided into areas for easy management and beautiful appearance.

[0041] Furthermore, the geotube bag should be made of high-toughness geotechnical materials with a joint strength of ≥85KN / m and a permeability of Q 50 ≥25L / (m 2 s);

[0042] And / or, the chemical ratio for geotube bags is: 0.5% PAC + (0.1% to 0.2%) PAM;

[0043] Planting floating plants, stem, bulb and seed plants, emergent herbaceous plants on the mud;

[0044] Preferably, the floating plants include water hyacinth and water celery;

[0045] Preferably, the stem, bulb and seed plants include water lily, lotus, water chestnut and Euryale ferox;

[0046] Preferably, the emergent herbaceous plants include reeds, water plantains, and cattails.

[0047] A treatment system for a river and lake ecological dredging construction method, a sludge system for land-based sludge discharge includes a sludge concentration tank system, a drug adding tank system, a transfer conditioning tank system, and residual water recovery facilities;

[0048] The dosing box system is arranged on the filter press unit side of the filter press plant near the dosing box, and the dosing box system, residual water recovery facilities, sludge concentration tank system, and transfer conditioning tank system are arranged in sequence.

[0049] The sewage treatment in this application adopts the method of CN202310358217.9, a method for cascade separation and purification and recycling of mud and water in lakeside wetland areas, for treatment.

[0050] The sludge pretreatment of the present application includes dredging the sludge by an environmentally friendly cutter suction dredger and transporting it to an onshore sludge discharge site through a sludge discharge pipe. The sludge is separated from the garbage, and the garbage is temporarily stored and then harmlessly treated. The separated sludge is discharged into an onshore primary sedimentation tank (mud pool) through a pipeline at the river and lake sludge input port.

[0051] The primary sedimentation tank is the main holding tank after the recovery of sludge, residual water from the onshore filter press plant and residual chemicals. The sludge in the tank is flocculated, precipitated and stratified under the dual effects of "physical self-settlement + chemical reaction of environmental protection chemicals". The residual water (tail water) enters the subsequent sedimentation and flocculation sludge system (to achieve cascade separation of mud and water, sedimentation and flocculation sludge + tail water purification and clarification) until it is purified to meet the primary emission standards.

[0052] Compared with the prior art, the river and lake ecological dredging construction method and treatment system described in the present invention have the following advantages:

[0053] 1. This application adopts three key technical routes of "concentration and conditioning + dehydration and consolidation", that is, this project adopts "concentration tank sludge concentration and conditioning + belt filter press dehydration and consolidation", "concentration tank sludge concentration and conditioning + transfer conditioning tank sludge secondary conditioning + plate and frame filter press dehydration and consolidation" and "geotube bag dehydration and consolidation" through scientific research experiments and construction practices. It adopts multiple scenarios, multiple systems and synchronous implementation, and is targeted at sludge of different particle sizes and different working conditions. It has strong pertinence, good treatment effect, high production capacity, no secondary pollution, safety, green and environmentally friendly, and provides technical parameters and quality standards for subsequent large-scale application in similar projects in the entire Chaohu Lake area and the entire basin around Chaohu Lake.

[0054] 2. The present application adopts three sludge dehydration and consolidation treatment process methods, namely, dredging the Chaohu Lake bottom mud by an environmentally friendly suction dredger, transporting it to land and water mud discharge sites through mud discharge pipes, using garbage screening devices to screen out garbage impurities for harmless treatment, and the separated mud and water enter the primary sedimentation tank (mud pool) for flocculation and sedimentation, and then transported to the mechanical filter press workshop of the land mud discharge site for filtration and consolidation, and transported to the geotube bag filling sludge field area of ​​the water mud discharge site for dehydration and consolidation. The moisture content index has reached the design requirements, and the dry mud thickness meets the construction production target requirements: 1) In the filter press workshop of the onshore mud discharge field, the bottom mud with a particle size of more than 16μm is filtered and dehydrated by a belt filter press, and the moisture content reaches below 55%, and the average thickness of the mud cake reaches about 3cm; 2) In the filter press workshop of the onshore mud discharge field, the bottom mud with a particle size of less than 16μm is filtered and dehydrated by a plate and frame filter press, and the moisture content reaches below 50%, and the average thickness of the mud cake reaches about 5cm; 3) In the water mud discharge field, the bottom mud with a particle size of more than 16μm and less than 16μm is dehydrated and consolidated by geotextile tube bags, and the moisture content reaches below 50%. The above indicators not only meet the construction quality, but also improve the construction efficiency and achieve the construction period control target.

[0055] 3. This application develops geotube dehydration and solidification, and wetland construction technology to solve the problem of the conflict between the original design of the water tube cofferdam, the lakeside wetland micro-topography structure and the Chaohu blue algae isolation and salvage equipment, and the poor functional effect of the original design of the micro-topography bagged earth cofferdam, solve the problem of the layout of shallows and deep waterways in narrow areas, solve the problem of tailwater treatment and discharge, and avoid secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0057] Figure 1 A schematic diagram of a process of a river and lake ecological dredging construction method according to an embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram of placing the geotube bag according to an embodiment of the present invention;

[0059] Figure 3 It is a schematic diagram of a dredging project in the prior art;

[0060] Figure 4 A schematic diagram of the desilting project layout for this application;

[0061] Figure 5 This is a photo of the dry mud cake solidified by the belt filter press (thickness about 10mm, moisture content ≤55%);

[0062] Figure 6Photos of mud cakes of different thickness filtered by the filter press unit;

[0063] Figure 7 Photo of dry mud cake consolidated by plate and frame filter press (thickness is large, the thickest is about 50mm, and the moisture content can reach about 40%)

[0064] Figure 8 It is an overall schematic diagram of a sludge concentration and conditioning agent treatment system according to an embodiment of the present invention;

[0065] Fig. 9 A schematic diagram of a sludge concentration tank device according to an embodiment of the present invention;

[0066] Fig.10 It is a side schematic diagram of the sludge concentration tank device according to an embodiment of the present invention;

[0067] Fig.11 It is a top schematic diagram of the sludge concentration tank device according to an embodiment of the present invention;

[0068] Fig.12 It is a schematic diagram of a medicine adding box device according to an embodiment of the present invention;

[0069] Fig.13 It is a top schematic diagram of the medicine adding box device according to an embodiment of the present invention;

[0070] Fig.14 It is a side schematic diagram of the medicine adding box device according to an embodiment of the present invention;

[0071] Fig.15 A schematic diagram of a second water supply pipe of the medicine adding box device according to an embodiment of the present invention;

[0072] Fig.16 It is a schematic diagram of another side of the medicine adding box device according to an embodiment of the present invention;

[0073] Fig.17 It is a schematic diagram of a transfer conditioning tank device according to an embodiment of the present invention;

[0074] Fig.18 It is a side schematic diagram of the transfer conditioning tank device described in an embodiment of the present invention.

[0075] Description of reference numerals: DETAILED DESCRIPTION

[0076] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0077] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0078] The sludge system for onshore sludge discharge includes a sludge thickening tank device, a sludge thickening and conditioning agent treatment system, including a sludge thickening tank system 1, a drug dosing box system 2, a transfer conditioning tank system 3, and a residual water recovery facility 7; the drug dosing box system 2 is arranged on the side of the filter press unit in the filter press plant near the drug dosing box, and the drug dosing box system 2, the residual water recovery facility 7, the sludge thickening tank system 1, and the transfer conditioning tank system 3 are arranged in sequence; the drug dosing box system 2 is provided with a drug box stirring component 2-5 and a liquid medicine delivery pump component 6; the sludge thickening tank system 1 is provided with a drainage component and a backwash component; one side of the sludge thickening tank system 1 is provided with a residual water recovery facility 7; the sludge thickening tank system 1 is connected to the filter press unit through a pipeline, or the sludge thickening tank system 1 and the transfer conditioning tank system 3 are connected through a pipeline, and the transfer conditioning tank system 3 is connected to the filter press unit through a pipeline.

[0079] The residual water recovery facility 7 is discharged into the main body of the residual water recovery open ditch in the plant area, and then flows into the land-based primary sedimentation tank 8. The residual water (tail water) finally enters the tail water purification stage until the first-level discharge standard is met. In addition, a certain concentration of medicines still remain in the water flow collected in the residual water recovery open ditch, which can still be fully utilized to participate in water purification in the land-based primary sedimentation tank 8 and the subsequent tail water purification stage, and will not be wasted. Residual water (tail water) recovery facility: It is composed of the residual water collection open ditch of the belt filter press unit, the residual water recovery open ditch of the plate and frame filter press unit, the main body of the residual water recovery open ditch in the plant area, the terminal drainage outlet of the residual water recovery open ditch, and the land-based primary sedimentation tank 8. It can collect residual water (tail water), recycle the residual liquid medicine, and make the residual water (tail water) enter the subsequent purification and clarification steps until it meets the discharge standards and is reused as a resource. The sludge thickening tank system 1 comprises a sludge thickening tank body 1-1; a drainage assembly is arranged at the top of the tank body; a backwash assembly is arranged at the bottom of the sludge thickening tank body 1-1; a conical mud collecting bin 1-6 at the bottom of the sludge thickening tank body 1-1 is arranged, and the bottom of the conical mud collecting bin 1-6 at the bottom of the thickening tank is supported by a concentrating tank bottom support structure 1-9; a mud outlet pipe is connected to the bottom of the conical mud collecting bin 1-6 at the bottom of the thickening tank, and the mud outlet pipe is connected to the transfer conditioning tank system 3 or the filter press unit; the drainage assembly comprises a drainage groove 1-2 at the top of the tank body, and the drainage groove 1-2 at the top of the tank body is arranged at the top of the sludge thickening tank body 1-1; the bottom of the drainage groove 1-2 at the top of the tank body is connected to the drainage tube 1-3 at the top of the tank body;

[0080] The bottom support structure 1-9 of the concentration tank includes a plurality of support rods, which are arranged below the conical sludge collection bin 1-6 at the bottom of the concentration tank. The residual water recovery facility 7 includes an open ditch 1-12 for recovering overflow water from the concentration tank and an overflow pipe 1-11 at the top of the concentration tank. The open ditch 1-12 for recovering overflow water from the concentration tank is arranged on one side of the sludge concentration tank body 1-1. One end of the overflow pipe 1-11 at the top of the concentration tank is connected to the top of the sludge concentration tank; the other end is connected to the open ditch 1-12 for recovering overflow water from the concentration tank; the recoil assembly includes two recoil pipes 1-7 at the bottom of the concentration tank, which are arranged at the bottom of the conical sludge collection bin 1-6 at the bottom of the concentration tank; the recoil pipe 1-7 at the bottom of the concentration tank is connected to the water supply pipe; the recoil pipes are at an angle of 45 degrees to the inner wall of the tank body, the recoil pipes are connected to the water pump and the water supply pipe, and the recoil pipe orifice is a high-pressure water spray port.

[0081] A sludge delivery pipe 1-4 is provided on one side of the sludge thickening tank body 1-1, and a first valve 1-8 is provided on the sludge delivery pipe 1-4; one end of the sludge delivery pipe 1-4 is connected to the sludge thickening tank body 1-1, and the other end is connected to the sludge in the sludge sedimentation tank; a liquid medicine delivery pump assembly 6 is provided on one side of the sludge thickening tank body 1-1; the liquid medicine delivery pump assembly 6 includes a sludge dosing pipe 1-5 and a second valve 1-13; the second valve 1-13 is arranged on the sludge dosing pipe 1-5, one end of the sludge thickening tank dosing pipe 1-5 is connected to the sludge thickening tank body 1-1, and the other end is connected to the dosing box system 2.

[0082] The drainage trough 1-2 on the top of the tank body includes a rectangular section with an opening on the top and an arc section with an opening on the top, and the rectangular section and the arc section are connected; a pipe baffle is provided on the upper part of the arc section, and the dosing pipe 1-5 of the concentration tank and the mud delivery pipe 1-4 of the concentration tank both enter the drainage trough 1-2 on the top of the tank body through the pipe baffle; the bottom of the rectangular section with an opening on the top is connected to the material receiving and drainage tube 1-3 on the top of the tank body; a ladder and a working platform channel 1-10 are provided on one side of the sludge thickening tank; the working platform channel is arranged at the top of the ladder and is arc-shaped, the working platform channel is connected to the ladder, and an operating panel is provided at the bottom of the working platform channel; the outer wall of the material receiving and drainage tube 1-3 on the top of the tank body is connected to the inner wall of the sludge thickening tank through a reinforcing plate.

[0083] The medicine adding box system 2 includes a first medicine adding and dissolving box 2-1 and a second medicine adding and dissolving box 2-10; the second medicine adding and dissolving box 2-10 is arranged on one side of the first medicine adding and dissolving box 2-1; the first medicine adding and dissolving box 2-1 and the second medicine adding and dissolving box 2-10 are both provided with a medicine box stirring assembly 2-5, and a liquid medicine delivery pump assembly 6 is arranged inside; the second medicine adding and dissolving box 2-10 and one side of the first medicine adding and dissolving box 2-1 are both provided with a medicine box fixing bracket 2-2; the inner walls of the first medicine adding and dissolving box 2-1 and the second medicine adding and dissolving box 2-10 are both provided with a water level alarm 2-4. The volume of the first medicine adding and dissolving box 2-1 is smaller than that of the second medicine adding and dissolving box 2-10; the first medicine adding and dissolving box 2-1 and the second medicine adding and dissolving box 2-10 are both added with the medicine PAM and PAC.

[0084] Or the reagents added to the second drug-adding and dissolving box 2-10 are PAM and PAC, the reagent added to the first drug-adding and dissolving box 2-1 is PAM, and the first drug-adding and dissolving box 2-1 supplements the PAM solvent concentration of the second drug-adding and dissolving box 2-10 through the second water supply pipe 2-9. Or the reagents added to the second drug-adding and dissolving box 2-10 are PAM and PAC, the reagent added to the first drug-adding and dissolving box 2-1 is PAC, and the first drug-adding and dissolving box 2-1 supplements the PAC solvent concentration of the second drug-adding and dissolving box 2-10 through the second water supply pipe 2-9. The medicine box stirring assembly 2-5 includes a first stirring motor, a first output rod, and an arc-shaped stirring blade; the first stirring motor is installed in the middle of the first medicine-dosing and dissolving box 2-1 or the second medicine-dosing and dissolving box 2-10 through a first mounting bracket; the first output rod is connected to the output end of the first stirring motor, and a plurality of arc-shaped stirring blades are evenly arranged on the first output rod; the medicine liquid delivery pump assembly 6 includes a medicine delivery pipeline 2-8; the medicine delivery pipeline 2-8 is arranged at the bottom of the first medicine-dosing and dissolving box 2-1 and the second medicine-dosing and dissolving box 2-10, and a booster water pump 2-6 is provided on the medicine delivery pipeline 2-8.

[0085] The first medicine-adding and dissolving box 2-1 and the second medicine-adding and dissolving box 2-10 are provided with a water delivery pump assembly 5; the water delivery pump assembly 5 includes a first water supply pipe 2-3 and a second water supply pipe 2-9; the first water supply pipe 2-3 is connected to the first medicine-adding and dissolving box 2-1 and the second medicine-adding and dissolving box 2-10 respectively, and a water supply valve is provided on the first water supply pipe 2-3; one end of the second water supply pipe 2-9 is connected to the first medicine-adding and dissolving box 2-1, and the other end is connected to the second medicine-adding and dissolving box 2-10; a water supply pump is provided on the second water supply pipe 2-9. A ladder is provided on one side of the medicine box fixing bracket 2-2, and a medicine box platform is provided on the upper part of the medicine box fixing bracket 2-2, and a first control cabinet 2-7 is provided on the medicine box platform, and the controller in the first control cabinet 2-7 is electrically connected to the water level alarm 2-4, the first stirring motor, the water supply valve, and the water supply pump respectively. The controller in the first control cabinet 2-7 adopts the existing PLC technology.

[0086] The transfer conditioning tank system 3 includes a first transfer conditioning tank body 3-1 and a second transfer conditioning tank body 3-8; the first transfer conditioning tank body 3-1 is arranged on one side of the second transfer conditioning tank body 3-8; a mud and water input pipe 3-2 and a chemical input pipe 3-3 are arranged on one side of the first transfer conditioning tank body 3-1 and the second transfer conditioning tank; the mud and water input pipe 3-2 is connected to the sludge concentration tank system 1, and the chemical input pipe 3-3 is connected to the chemical adding tank system 2; a mud and water input valve is arranged on the mud and water input pipe 3-2, and a chemical input valve is arranged on the chemical input pipe 3-3. Chemicals PAM and PAC are added into the first transfer conditioning tank body 3-1 and the second transfer conditioning tank body 3-8; if different sludges are treated, different proportions of the added chemical PAM and PAC are used to adjust sludge of different particle sizes. A transfer conditioning and stirring assembly 3-5 is provided in the middle of the transfer conditioning tank system 3; the transfer conditioning and stirring assembly 3-5 includes a second stirring motor, a second output rod, and a transfer conditioning and stirring blade; the middle of the first transfer conditioning tank body 3-1 and the second transfer conditioning tank body 3-8 are both installed with a second stirring motor through a second mounting bracket; the second output rod is connected to the output end of the second stirring motor, and a plurality of transfer conditioning and stirring blades are evenly arranged on the second output rod; a transfer conditioning ladder 3-7 is provided on one side of the transfer conditioning tank body, a transfer conditioning platform is provided on the top of the transfer conditioning ladder 3-7, and a second control cabinet 3-6 is provided on the transfer conditioning platform; the controller in the second control cabinet 3-6 is electrically connected to the mud and water input valve, the reagent input valve, and the second stirring motor respectively. The controller in the second control cabinet 3-6 adopts the existing PLC technology.

[0087] Example 1

[0088] The sludge thickening tank body 1-1 of the sludge thickening tank system 1 is installed on a reinforced concrete pedestal foundation, and the lower part of the pedestal foundation is supported by concrete pipe piles (the bottom support structure 1-9 of the thickening tank); the sludge thickening tank body 1-1 is arranged in a straight line outside the filter press plant, with a total of 14 sets, and the effective volume of a single tank is about 120 cubic meters. It is made of 6 sets of Q235B annular steel plates (thickness 5mm) with a diameter of 4.6m welded and assembled into a cylindrical container. The total height of the tank container of the sludge thickening tank 1-1 is about 8.5m, and is equipped with a ladder and work platform passage 1-10 for daily inspection and sampling (tank safety ladder, tank top safety walkway and guardrail, welded to the tank top reinforcement support); the support legs at the lower part of the tank are 6 DN300 Q235B steel pipes (wall thickness 8mm) (thickness of the bottom support structure of the thickening tank 1-9), and in addition, 2 DN100 cross-support steel pipes are welded between every two support legs to enhance the stability of the tank support; a DN200 thickening tank mud delivery pipe 1-4 and a DN50 thickening tank dosing pipe 1-5 are set at the upper mouth of the tank, and a DN260 thickening tank top overflow pipe 1-11 is set at the overflow port position on the top of the tank. The sludge thickening tank system 1 is a temporary storage container for sludge. The sludge from the onshore primary mud sedimentation tank is input into the tank body by an environmentally friendly suction boat through a mud conveying pipe. The sludge is flocculated, concentrated, conditioned and precipitated in the tank body. The concentrated mud-water mixture with a higher concentration sinks to the middle and lower part of the tank body, and is transported from the mud outlet at the bottom of the cone mud bin to the filter press unit for pressure filtration, dehydration and consolidation into dry mud (dry mud moisture content within 55%). The residual water generated by the pressure filtration and consolidation needs to be recycled; the upper space of the tank body is basically supernatant, and the supernatant exceeding the overflow port height (i.e., the residual water of residual agents and extremely fine particle sludge) is discharged from the overflow pipe 1-11 at the top of the concentration tank, and discharged to the overflow water recovery open ditch 1-12 of the concentration tank through the lower port of the overflow pipe 1-11 at the top of the concentration tank.

[0089] A drainage trough 1-2 on the top of the sludge thickening tank body 1-11 is installed on the top of the tank body, which is similar to the shape of a "sickle". The arc section (the curvature of the drainage trough is roughly the same as the curvature of the outer edge of the tank container, and is welded and fixed to the outer edge of the top of the tank body) is about 3.5m long, about 400mm wide, and about 400mm high. One end of the rectangular section is vertically welded and spliced ​​with the arc section at a 90-degree angle, and the other end is welded and fixed just above the material receiving drainage tube on the top of the tank body. The rectangular section is about 2.6m long, about 400mm wide, and about 400mm high. It is made of Q235B annular steel plate (thickness 3mm) welded and assembled. The top surface of the drainage trough 1-2 on the top of the tank body is completely open, and the muddy water transported by the thickening tank mud delivery pipe 1-4 and the liquid medicine transported by the thickening tank dosing pipe-15 are received by installing a pipeline baffle;

[0090] Only the rectangular section of the drainage groove bottom surface near the tank top material receiving drainage tube has a small opening (the opening size is about 390mm*390mm) that is not closed, and the rest of the sections of the drainage groove are welded and closed by steel plates, and muddy water and liquid medicine flow from this bottom opening into the tank top material receiving drainage tube 1-3 directly below it. The flow direction slope of the tank top drainage groove 1-2 is about 2.5%, which is convenient for guiding muddy water and liquid medicine to be transported to the tank top material receiving drainage tube 1-3. The "sickle" shaped drainage groove can also use the arc and angle to slow down the scouring force of muddy water and liquid medicine, slow down the impact of flow velocity, and prevent overflow.

[0091] (3) Tank top material receiving and drainage tube 1-3: A tank top material receiving and drainage tube 1-3 is arranged at the center of the top of the sludge thickening tank 1-1. The diameter is about 500 mm and the length of the tube is about 2 m. The outer wall of the drainage tube is fixed by a set of upper and lower reinforced steel plate support assemblies (the steel plate supports are evenly and equidistantly arranged along the ring of the tube, a total of 8). The two ends of the steel plate support are respectively welded to the inner wall of the thickening tank and the outer wall of the drainage tube. The steel plate support is 200 mm wide and 5 mm thick. The length of the steel plate is the distance between the tank and the tube.

[0092] The top of the drainage tube is about 200mm higher than the top of the concentration tank. The upper surface of the top steel support of the drainage tube 1-3 at the top of the tank body is paved with a 3mm thick steel plate. The steel plate platform is a circular steel plate with an inner diameter of about 502mm. It is sleeved on the outside of the drainage tube and welded to it. The outer diameter of the steel platform is about 2.5m. It serves as a ladder and a working platform channel 1-10. The platform is welded with a 1.2m high safety guardrail. After the drainage trough 1-2 at the top of the tank body slows down the flow rate and impact force of muddy water and liquid medicine, the drainage tube 1-3 at the top of the tank body can reduce the impact force of muddy water and liquid medicine flow again, can collect and guide muddy water or liquid medicine to accurately flow into the tank body, can guide muddy water and liquid medicine to flow into the central part of the tank body and then spread to the surroundings without excessive sinking, and ensure the overall stability of the tank body.

[0093] Thickening tank mud pipe 1-4: A DN200 Q235B steel thickening tank mud pipe 1-4 with a wall thickness of 3mm is arranged along the outer wall from the bottom to the top of the sludge thickening tank body 1-1. One end of the bottom of the thickening tank mud pipe 1-4 is connected to the dredging ship mud pipe or the mud pump mud pipe, and the mud and water are transported from the onshore primary sedimentation tank to the sludge thickening tank system 1. The other end of the thickening tank mud pipe 1-4 is at the top of the tank body, just above the drainage trough 1-2 at the top of the tank body. The pipe mouth is bent 180 degrees and extends downward into the drainage trough, which is the transportation and inlet end of the mud and water. Concentration tank dosing pipe 1-5: A DN50 Q235B steel dosing pipe with a wall thickness of 2mm is arranged along the outer wall of the sludge concentration tank body 1-1 from the bottom to the top of the tank body; one end of the bottom of the concentration tank dosing pipe 1-5 is connected to the drug delivery pipeline of the dosing box system, and the other end of the concentration tank dosing pipe 1-5 is directly above the drainage groove 1-2 at the top of the tank body. The pipe mouth is bent 180 degrees and extends downward into the drainage groove, which is the delivery inlet end of the drug solution.

[0094] Conical mud collection bin 1-6 at the bottom of the concentration tank: A conical mud collection bin is also welded and assembled at the bottom of the concentration tank body. The diameter of the upper part of the cone is the same as that of the tank body, and the height of the cone is about 2m. It is the main storage part for receiving mud water and liquid medicine, and for mud water concentration, conditioning and sedimentation. The mud concentration here is relatively high and viscous. A mud outlet and a recoil device are provided at the bottom of the bin, which is also the outlet end of the concentrated mud. The mud outlet is connected to the mud pipe and the gate valve. The mud pipe is connected to the mud pump, which can transport the concentrated mud to the filter press unit assembly for dehydration and consolidation. After the concentrated mud in the mud collection bin is discharged and transported, the remaining supernatant on the upper part can also be discharged into the overflow water recovery open ditch 1-12 of the concentration tank through the three-way port of the mud pipe connected to the mud outlet at the bottom of the bin. Recoil pipe 1-7 at the bottom of the concentrator tank: To prevent the concentrated and precipitated sludge in the conical mud collection bin at the bottom of the concentrator tank from clogging the mud outlet, two sets of recoil pipes 1-7 at the bottom of the conical bin are arranged on both sides above the mud outlet, with the pipe openings extending deep into the mud collection bin. The two sets of recoil pipes 1-7 at the bottom of the conical bin are arranged symmetrically, and the recoil pipes are respectively at an angle of 45 degrees to the inner wall of the tank body. The recoil pipes are connected to a water pump and a water supply pipe. The recoil pipe openings are high-pressure water spray nozzles, which can spray high-pressure water as needed to appropriately improve the mud concentration at the mud collection bin outlet. The water pressure range is 0.3 to 1.0 MPA, which can be adjusted by a pressure pump. The concentrated mud in the mud collection bin is driven to flow by high-pressure water flow, and the flow rate is adjusted to prevent blockage at the bottom of the mud collection bin and promote the mud to flow smoothly into the mud outlet.

[0095] According to work needs, gate valves and pressure gauges are installed on various pipelines attached to the concentration tank to open the pipelines and adjust the pressure of conveying mud and liquid medicine. Bottom support structure 1-9 of the concentration tank: The total height of the container of the recoil pipe at the bottom of the concentration tank is about 8.5m. The support legs at the bottom of the tank body are 6 DN300 Q235B steel pipes (wall thickness 8mm). In addition, 2 DN100 cross-support steel pipes are welded between every two support legs to enhance the stability of the tank body support. Ladder and working platform channel 1-10: The sludge concentration tank body 1-1 is equipped with a tank body safety ladder, a tank body top safety walkway, a working platform and guardrails for daily inspection and sampling (the ladder and working platform channel 1-10 are welded to the tank body top reinforcement support); the working platform is equipped with a video monitoring system and lighting to facilitate video information collection, daily inspection and safety management, and maintenance and test sampling.

[0096] Overflow pipe 1-11 on top of concentrator tank: Overflow pipe on top of concentrator tank Overflow pipe 1-11 on top of concentrator tank is an accessory and structure of sludge concentrator tank, installed on the outer wall of each concentrator tank body, and facing the open ditch 1-12 of overflow water recovery of concentrator tank on the side of filter press plant. Overflow pipe of concentrator tank is a DN260 Q235B steel pipe with a wall thickness of 3mm. The pipe is welded by supporting connecting steel plate and installed on the outer wall of sludge concentrator tank body. The upper end of the pipe is connected to the overflow port at the top of open ditch 1-12 of overflow water recovery of concentrator tank. The outflowing sewage enters the overflow pipe through the upper end of the pipe and flows down. The outlet at the end of the overflow pipe is toward the overflow water recovery ditch 1-12 of the concentration tank. The outlet of the pipe makes a 135-degree turn to reduce the speed of the water flow and prevent muddy water from splashing out. A total of 14 sets of concentration tanks are installed outside the filter press plant, equipped with a total of 14 sets of overflow pipes. The sewage overflowing from each overflow pipe will flow into the overflow water recovery ditch 1-12 of the concentration tank respectively. The overflow water recovery ditch 1-12 of the concentration tank is located at the bottom of the pipe and is specifically used to receive the sewage discharged from the overflow pipe.

[0097] The open ditch 1-12 for recovering overflow water from the concentration tank is cast on-site with C20 plain concrete, with a length, width and depth of 100m*0.6m*0.6m respectively, a slope of about 1.5%, a wall thickness of about 100mm for the concrete open ditch, and a bottom plate thickness of about 150mm. The structure is safe, reliable and leak-proof, and a cast iron grille cover is laid at the pedestrian passage. The open ditch is located between the filter press building and the concentration tank. Its layout is scientific and reasonable. It fully considers and utilizes the limited narrow space between the foundation of the concentration tank pedestal and the foundation of the filter press building. It extends straight along the 14-component concentration tank to the main body of the residual water recovery open ditch in the plant area. It is specifically used to collect sewage discharged from the overflow pipe of the concentration tank, and the sewage is discharged into the main body of the overflow water recovery open ditch 1-12 of the concentration tank, and then flows into the onshore primary sedimentation tank. The residual water (tail water) finally enters the tail water purification stage until the first-level emission standard is met. In addition, there is still a certain concentration of chemicals remaining in the water flow collected in the residual water recovery open ditch, which can still be fully utilized in the onshore primary sedimentation tank and the subsequent tail water purification stage, and will not be wasted.

[0098] Example 2

[0099] The dosing box system 2 is used to add drugs to the sludge thickening tank system 1, the transfer conditioning tank system 3, the belt filter press unit, and the plate and frame filter press unit. Its functions are to add drugs, dissolve drugs, mix them, and transport them. A total of 12 sets are set up and arranged in the filter press plant of the onshore mud discharge site near the sludge thickening tank system 1.

[0100] Dosing and dissolving box 2-1: The box is made of Q235B steel. Each component of the dosing and dissolving box 2-1 is divided into two independent chambers, which can independently mix two agents with different dosages and ratios at the same time to meet the needs of different working conditions; among them, the dimensions of the 1# rectangular box are 2500mm×1800mm×3000mm in length, width and height, with a wall thickness of 3mm, and the dimensions of the 2# rectangular box are 1800mm×1800mm×1000mm in length, width and height, with a wall thickness of 3mm. It has its own steel operating platform and maintenance ladder, and its function is to add medicine, dissolve medicine and mix the liquid medicine.

[0101] (2) Medicine box fixing bracket 2-2 and operating platform: Made of Q235B steel, with a wall thickness of 3mm, the operating platform and maintenance ladder serve as fixing brackets for components and boxes, storing control cabinets, and are also used for maintenance, observation, daily maintenance, and climbing up and down the ladder.

[0102] (3) Agitation pump assembly: The motor power is 5kw and is installed on the fixed bracket above the medicine box dosing port. The steel fixed bracket is made of Q235B profile. The lower end of the agitation pump assembly is a stirring blade connected by a steel bearing. Its function is to drive the stirring blade at the lower end to stir the dissolved medicine and adjust the liquid medicine after water and medicine are added to the medicine box.

[0103] (4) Water supply pipe and gate valve: φ50mm galvanized water pipe and ball valve, which are used to provide water for the dosing and dissolving box.

[0104] (5) Water level alarm 2-4: A float type automatic water level alarm, which automatically monitors the water level in the medicine box. When the water level is too low or too high, it will automatically alarm to remind the operator to take measures.

[0105] (6) Booster water pump 2-6: The power is 3 kW and the maximum pressure it can provide is 1.6 MPa. It is installed at the medicine outlet at the bottom of the medicine box. The input pipe is connected to the bottom of the medicine box and the output pipe is connected to the medicine delivery pipe 2-8. Its function is to pressurize and deliver the medicine solution to the dosing point.

[0106] (7) Control cabinet device: It is composed of a multi-component electrical control cabinet device, which has automatic and manual control systems and operation buttons. It is installed on the steel operating platform of the dosing and dissolving box. Its function is equipment control, mainly controlling the mixing pump assembly, booster pump, water level alarm 2-4 and video monitor, etc.

[0107] (8) Chemical delivery pipeline 2-8: Made of Q235B galvanized steel pipe, it can withstand a maximum pressure of 1.6 MPa, has a diameter of DN100 and a wall thickness of 4.0 mm. The chemical delivery pipeline 2-8 is connected to the output end of the booster pump 2-6 and is used to deliver the chemical solution to the dosing point.

[0108] (9) In addition, the chemicals added, mixed, dissolved and transported by the dosing box system 2 are environmentally friendly chemicals (PAM+PAC), the proportion of which comes from production pre-work tests and process monitoring sampling test data to meet different working conditions and different purification stages, and are supplied to each dosing point, which is highly targeted, accurate and reliable.

[0109] Example 3

[0110] 3. Transfer conditioning tank system 3

[0111] For sludge with particle size below 16 microns, an additional transfer conditioning tank body 3-1 is set up, which has the function of transfer + secondary conditioning, that is, after the first concentration and conditioning in the concentration tank, when the dehydration consolidation output and moisture content of the belt filter press unit are not well controlled, the transfer conditioning tank system 3 can be selected to carry out secondary transfer conditioning of the sludge and water, and then transport it to the plate and frame filter press unit for dehydration and consolidation, so as to achieve the goal that the dehydration and consolidation output meets the construction period requirements and the moisture content meets the design requirements.

[0112] (1) Tank body: The transfer and conditioning tank body 3-1 is a Q235B steel cylindrical tank body with a diameter of 2m and a height of 2m. It is used to store muddy water that needs to be transferred and conditioned. After adding the medicine, it is stirred and conditioned in the tank body.

[0113] (2) Mud and water input pipe 3-2: DN200 Q235B steel mud pipe with a wall thickness of 2mm. One end of the mud pipe is connected to the mud pump pipe outlet at the bottom of the concentration tank, and the other end is connected to the transfer conditioning tank to input mud and water into the tank.

[0114] (3) Drug input pipe 3-3: DN50 Q235B steel dosing pipe with a wall thickness of 2mm; one end of the bottom of the dosing pipe is connected to the drug delivery pipeline of the dosing box, and the other end is connected to the transfer conditioning tank to transport the drug solution into the tank.

[0115] (4) Mud output pipe 3-4: DN200 Q235B steel mud pipe with a wall thickness of 2mm. One end of the bottom of the mud pipe is connected to the mud pump pipe of the transfer conditioning tank, and the other end is connected to the mud pump pipe that transports mud water to the plate and frame filter press unit. The conditioned mud water can be transported from the transfer conditioning tank to the plate and frame filter press unit.

[0116] (5) Transfer conditioning and stirring component 3-5: The power is 5kw. It is installed on the second mounting bracket of the transfer conditioning and stirring component above the tank body. The steel fixed bracket is made of Q235B profile. The lower end of the transfer conditioning and stirring component is a stirring blade connected to a steel bearing. Its function is to drive the blade at the lower end to rotate to stir and condition the mud water and the liquid medicine, promote the reaction of the mud water and the medicine, make the mud water flocculate and precipitate, and adjust its concentration, so as to increase the output of the plate and frame filter press during the dehydration and consolidation of the mud water and reduce the moisture content of the dry mud cake.

[0117] (6) The second control cabinet 3-6 is composed of a multi-component electrical control cabinet assembly, which has automatic and manual control systems and operating buttons. It is installed on the steel operating platform of the tank body. Its function is equipment control, mainly controlling the transfer conditioning and stirring components 3-5 and the water level alarm 2-4. The second controller 3-6 adopts the existing PLC technology.

[0118] (7) Transfer and adjustment ladder: Made of Q235B steel, with a wall thickness of 3mm, the function of the operating platform and maintenance ladder is to serve as a fixed bracket for components and tanks, store control cabinets, and also be used for maintenance, observation, daily maintenance and climbing up and down the ladder.

[0119] Example 4

[0120] Residual water recovery facility 7: It is mainly composed of open ditches for recovering residual water (tail water) from various locations, namely, an open ditch for recovering overflow water (residual water) from a concentration tank, an open ditch for collecting residual water from a belt filter press unit, an open ditch for recovering residual water from a plate and frame filter press unit, a main body of an open ditch for recovering residual water in a plant area, a drainage outlet at the end of an open ditch for recovering residual water, and an onshore primary sedimentation tank 8. It can collect residual water (tail water), recycle residual liquid medicine, and allow the residual water (tail water) to enter subsequent purification and clarification steps until it meets the discharge standards and is reused as a resource.

[0121] The residual water (tail water) recovery open ditch is cast on-site with C20 plain concrete, with a total length of about 300m, a width and depth of 0.6m*0.6m respectively, a slope of about 1.5%, a wall thickness of about 100mm for the concrete open ditch, and a bottom plate thickness of about 150mm. The structure is safe, reliable and leak-proof, and cast iron grille covers are laid on the pedestrian walkway. Among them, the overflow water (residual water) recovery open ditch of the concentration tank is located between the filter press building and the concentration tank. Its layout is scientific and reasonable, and it fully considers and utilizes the limited narrow space between the foundation of the concentration tank pedestal and the foundation of the filter press building. It extends straight along the 14 components of the concentration tank to the main body of the residual water recovery open ditch in the plant area, and is specifically used to collect sewage discharged from the overflow pipe of the concentration tank, and discharge it into the main body of the residual water recovery open ditch in the plant area, and then flows into the onshore primary sedimentation tank 8; other belt filter press unit residual water collection open ditches, plate and frame filter press unit residual water recovery open ditches, and plant area residual water recovery open ditches. The main bodies of the water recovery open ditch are distributed near the equipment sites inside the filter press plant, and are specifically used to collect the residual water (tail water) generated by each of them, which are all collected at the drainage outlet at the end of the residual water recovery open ditch, and finally discharged to the onshore primary sedimentation tank 8 (mud tank). The residual water (tail water) eventually enters the tail water purification stage until the first-level emission standard is met; in addition, a certain concentration of chemicals still remain in the water flow collected in the residual water recovery open ditch, which can still be fully utilized to participate in water purification in the onshore primary sedimentation tank 8 and the subsequent tail water purification stage, and will not be wasted.

[0122] Drainage outlet at the end of the open ditch for residual water recovery: a corrugated pipe with a long diameter of 600mm crosses the site road and is buried below the roadbed. One end is connected to the end of the open ditch for residual water recovery, and the outer periphery of the pipe mouth is sealed with waterproof concrete to prevent water seepage. The other end of the pipe mouth goes deep into the onshore primary sedimentation tank 8, and the residual water (tail water) can directly flow into the onshore primary sedimentation tank 8 through the pipe mouth to complete the recovery of the residual water (tail water).

[0123] Onshore primary sedimentation tank 8: Onshore primary sedimentation tank 8 is located in the cofferdam between the onshore mud field and the lakeside wetland. The cofferdam is a clay-filled cofferdam, and the surface is covered with ordinary composite anti-seepage geotextile (two fabrics and one film, with a specification of (200g / m 2 ) / 0.5mm / (200g / m 2)); the bottom width of the cofferdam is 33.1m, the top width is 2m, and the height is 7m; the effective area of ​​the sedimentation tank is about 18,225 square meters, the volume is about 91,125 cubic meters, and it can store about 82,012 cubic meters of muddy water, which is more than 24 hours of dredging volume. The average sedimentation and flocculation time of the onshore sedimentation tank is more than 24 hours, so there will be more than 1 / 3 of surface clean water in the surface flow. The onshore primary sedimentation tank 8 receives the mud water screened and filtered by the river and lake bottom mud input port. It is the main holding tank for the dredged mud from Chaohu Lake, so it is also commonly known as the mud tank. In addition, the residual water from the onshore filter press solidification production workshop and the overflow residual water from the concentration tank also flow back to the onshore primary sedimentation tank 8. The residual water contains environmentally friendly chemicals remaining in the sludge solidification process. The chemicals can promote the bottom mud sludge in the sedimentation tank, which not only realizes the reuse of residual chemicals and avoids the waste of chemicals, but also improves the effect of bottom mud flocculation and sedimentation of flocculated sludge. The rear part of the onshore primary sedimentation tank 8 is other multi-stage sedimentation tanks for purification and clarification of residual water (tail water).

[0124] This system is arranged in the filter press building and sedimentation tank area of ​​the onshore mud discharge field; 14 groups of sludge thickening tank systems 1 are arranged in a straight line in the shape of a "one" outside the filter press building, one side of which is the dosing box inside the filter press building, and the other side is the onshore mud sedimentation tank and tailwater sedimentation tank; 12 groups of dosing boxes are arranged in a straight line in the shape of a "one" inside the filter press building, one side is the filter press unit, and the other side is the thickening tank outside the filter press building; 6 groups of transfer conditioning tanks are arranged near the plate and frame filter press unit inside and outside the building, and are arranged side by side with the thickening tanks near them; the thickening tank and the dosing box are separated by the steel structure outer wall of the filter press building, and an open ditch for tailwater recovery is built between the foundation of the outer wall of the building and the foundation of the thickening tank, and another open ditch for tailwater recovery is built between the dosing box inside the building and the filter press unit, and the open ditch merges outside the building and is connected to the onshore primary sedimentation tank (mud pool). Video surveillance cameras, lighting equipment and environmental monitoring devices are installed inside and outside the factory, and safety guardrails and passages are set up near water, edges and high places.

[0125] Example 5

[0126] Onshore mud discharge: During the initial temporary construction, the system was arranged in the filter press building and sedimentation tank area of ​​the onshore mud discharge field according to the plan; 14 groups of concentration tanks were arranged in a straight line in the shape of a "one" outside the filter press building, one side of which was the dosing box inside the filter press building, and the other side was the onshore mud sedimentation tank and tailwater sedimentation tank; 12 groups of dosing boxes were arranged in a straight line in the shape of a "one" inside the filter press building, one side was the filter press unit, and the other side was the concentration tank outside the filter press building; 6 groups of transfer conditioning tanks were arranged near the plate and frame filter press unit inside and outside the building, and were arranged side by side with the concentration tanks near them; the concentration tank and the dosing box were separated by the steel structure outer wall of the filter press building, and an open ditch for tailwater recovery was built between the foundation of the outer wall of the building and the foundation of the concentration tank, and another open ditch for tailwater recovery was built between the dosing box inside the building and the filter press unit, and the open ditch merged outside the building and connected to the onshore primary sedimentation tank 8 (mud tank). Video surveillance cameras, lighting equipment and environmental monitoring devices are installed inside and outside the factory, and safety guardrails and passages are set up near water, edges and high places.

[0127] According to the method of the present invention, the lakeside wetland area near the Chaohu embankment outside the project site is first measured and laid out according to the red line of land acquisition, the original humus soil of the lakeside wetland is stripped and temporarily stored, and the aquatic plants and animals in the wetland are relocated and properly resettled as required (to be reclaimed and restored after completion). Then, according to the final implementation plan and layout diagram, the onshore mud field is constructed, that is, the filter press workshop site and factory facilities of the onshore mud field are constructed according to the plan, and the onshore first-level sedimentation tank 8 (mud tank) cofferdam and other sedimentation tanks of various levels are constructed. After the production pre-work test is completed, formal production can be carried out according to the process flow. The specific operation mode is as follows:

[0128] Optimize the sediment garbage screening scheme and develop a screening device to separate mud and garbage: The Chaohu sediment is dredged by an environmentally friendly suction dredger and transported to an onshore sediment discharge site through a sediment discharge pipe. A sludge screening, filtering and diversion device (invention patent: ZL202221191455.2) separates the sediment from the garbage. The garbage is temporarily stored and then harmlessly treated. The separated sediment is discharged into the onshore primary sedimentation tank 8 (mud tank) through a pipeline at the river and lake sediment input port.

[0129] During the dredging construction of this project, the diffusion distance of suspended matter in the water body is required to be no more than 50m, and the dredging excavation depth error is controlled within 0-5cm to ensure that the dredged sludge concentration is not less than 10%; under-dredging is not allowed, and the dredged sludge concentration must be ensured to be no less than 10%. Since the disturbance of the auger during dredging by the dredger will cause the sludge particles on the bottom of the lake to spread to the outer water area, which is easy to cause secondary pollution, it is necessary to strictly control the impact range of the dredger during dredging. The Dutch IHC environmentally friendly dredger is equipped with environmental protection devices, including anti-diffusion protection cover, environmental protection auger head and oil-water separator, etc., which has little disturbance to the water body during construction. The dredger is also equipped with GPS global positioning system, depth sounder and pollution detection device, trench section monitoring device, dredging trajectory display device, etc., which can ensure the dredging excavation accuracy and concentration, and control the diffusion distance of suspended matter in the water body to not exceed 50m during dredging and dredging, so as not to cause secondary pollution.

[0130] The primary sedimentation tank 8 is the main holding tank after the recovery of the sludge, residual water from the onshore filter press plant and residual chemicals. The sludge in the tank is flocculated, precipitated and stratified under the dual effects of "physical self-settlement + chemical reaction of environmental protection chemicals". The residual water (tail water) enters the subsequent sedimentation and flocculation sludge system (to achieve mud and water cascade separation, sedimentation and flocculation sludge + tail water purification and clarification) until it is purified to meet the primary emission standards.

[0131] According to the process method of the present invention, the Chaohu sludge is first dredged by an environmentally friendly suction dredger and transported to the primary mud sedimentation tank of the onshore sludge field through a sludge discharge pipe. It is then required to undergo concentration conditioning, dosing, secondary mixing conditioning (optional), concentrated flocculation, and sedimentation of flocculated sludge, and then transported to the filter press unit in the filter press workshop of the onshore sludge field of the project for filtration, dehydration and consolidation, residual water (tail water) recovery, tail water purification, resource reuse, and consolidation of dry mud for resource recovery and mine backfilling for ecological restoration.

[0132] The onshore primary sedimentation tank (mud tank) is the main onshore holding tank for dredging and transporting sludge from Chaohu Lake. It is the residual water recovery holding tank for the onshore filter press and solidification production workshop. It is the place where the sludge is initially divided into regions and layers for "physical + chemical" flocculation and sedimentation of flocculated sludge. It is also the transit storage tank where the sludge is temporarily stored before being transported to the concentration tank and filter press and solidification production workshop.

[0133] The onshore primary sedimentation tank is located within the cofferdam between the onshore mud field and the lakeside wetland. The cofferdam is a clay-filled cofferdam, and the surface is covered with ordinary composite anti-seepage geotextile (two fabrics and one film, with a specification of (200g / m 2 ) / 0.5mm / (200g / m 2)); the bottom width of the cofferdam is 33.1m, the top width is 2m, and the height is 7m; the effective area of ​​the sedimentation tank is about 18,225 square meters, the volume is about 91,125 cubic meters, and it can store about 82,012 cubic meters of muddy water, which is more than 24 hours of dredging volume. The average sedimentation and flocculation time of the onshore sedimentation tank is more than 24 hours, so there will be more than 1 / 3 of surface clean water in the surface flow.

[0134] The sludge from the onshore sludge dump was dehydrated and consolidated using a filter press, and a total of 1.288 million cubic meters of sludge was processed.

[0135] The onshore primary sedimentation tank receives the mud water after screening and filtration at the river and lake bottom mud input port. It is the main storage tank for the mud dredged from the Chaohu bottom mud, so it is also commonly known as the mud tank. In addition, the residual water from the onshore filter press solidification production workshop also flows back to the onshore primary sedimentation tank. The residual water contains environmental protection chemicals left over from the sludge solidification process. The chemicals can promote the sedimentation of bottom mud in the sedimentation tank, which not only realizes the reuse of residual chemicals and avoids the waste of chemicals, but also improves the effect of bottom mud flocculation and sedimentation.

[0136] The sludge cascade sedimentation flocculation sludge adopts a combination of physical sedimentation + chemical sedimentation flocculation sludge. The bottom mud in the sedimentation tank is initially flocculated and precipitated with the help of physical self-settlement and chemical reaction of reagents. The coarse-grained sludge with larger particle size (particle size above 20 microns) is first settled at the front end of the pool, the medium-grained sludge with finer particle size (particle size 14.27 microns to 16 microns) is settled in the middle of the pool, and the extremely fine particles (particle size below 14.27 microns) are settled at the end of the pool; the mud with a higher concentration at the bottom of the sedimentation tank is transported by a small environmentally friendly suction boat or a small mud pump in the pool to the onshore sludge thickening tank for further flocculation and precipitation, and then the thickening tank pump group pipeline The system is used for dehydration and consolidation into dry mud cakes in the onshore filter press and solidification production workshop, which are then shipped to the mine via a belt conveyor system, and the resources are reused in mine ecological restoration. The residual water from the solidification process in the onshore filter press and solidification production workshop flows back to the sedimentation tank, and the remaining environmental protection agents and a small amount of fine-particle sludge in the residual water flow again in the sedimentation tank, and the fine-particle sludge continues to precipitate and flocculate sludge, while the surface tail water flows toward the overflow dam. The sludge on the surface of the sedimentation tank that is relatively clear but still contains fine particles is diverted with the tail water through the diversion weir, and flows into the secondary sedimentation tank (clear water tank) through the overflow weir of the overflow dam, and continues to enter the next stage of sedimentation and flocculation sludge process.

[0137] In summary, the coarse sludge with larger particle size (particle size above 20 microns) is in the front area of ​​the primary sedimentation tank, the medium sludge with finer particle size (particle size 14.27 microns to 16 microns) is in the middle area of ​​the primary sedimentation tank, and the sludge with extremely fine particles (particle size below 14.27 microns) is precipitated and flocculated in the terminal area of ​​the primary sedimentation tank. The sludge of the concentration and conditioning system transported to the filter press plant comes from the above three locations. Before transportation, the site tester will take on-site samples from the front, middle and back three drainage areas of the pool according to the work plan, and measure the sludge particle size in the laboratory to provide a basis for the subsequent selection of reagent ratios, concentration conditioning and filter press units.

[0138] Optimize the original design plan and add 6 sets of plate and frame filter press equipment to dehydrate and consolidate fine granular sludge with a particle size of less than 16μm: Since the belt filter press unit configured according to the design is only suitable for processing bottom mud with a particle size of more than 16 microns, if the particle size is lower than 16 microns, it will be difficult to control the moisture content of the consolidated dry mud and the thickness of the dry mud cake, which cannot meet the design index requirements (the design requires the moisture content of the consolidated dry mud to be ≤55%) and the construction schedule requirements (the thickness of the consolidated dry mud cake must be ≥20mm, and the average operation time of the on-site equipment must be more than 10 hours to meet the construction schedule requirements). During the on-site trial production, the belt filter press unit added 0.5% PAC + 0.05% PAM as the reagent to the concentration tank of the belt filter press for fine particles with a particle size below 16 microns; the moisture content of the dry mud consolidated by the filter press was about 60%, which was greater than the moisture content limit index required by the design, and the thickness of the dry mud after consolidation was less than 10mm, and only about 2mm at the thinnest. The fine particles of the bottom mud passed through the filter cloth of the belt filter press unit and were lost with the residual water (tail water). It could not be successfully consolidated and filtered, and the normal mass production target could not be achieved, and the construction period could not be guaranteed.

[0139] Therefore, the project has additionally configured 6 sets of plate and frame filter press units to assist in processing sludge with particle sizes below 16 microns. The sludge with particle sizes below 16 microns can be filtered into a mud cake that meets the design index requirements (the design requires that the moisture content of consolidated dry mud is ≤55%), and the thickness of the consolidated dry mud cake is ≥20mm, and the thickest can reach 50mm. However, the working mode of the plate and frame filter press unit is to fill the mud once, continue to filter once, and after the filter pressing and consolidation are completed, refill the mud and re-filter the consolidated dry mud. Unlike the belt filter press that continuously fills the mud and continues to filter and consolidate, the plate and frame filter press has pauses during working time and cannot be continuous. The reagent added to the concentration tank of the plate and frame filter press is: 0.5% PAC + 0.05% PAM; however, the use of a plate and frame filter press can make up for the problem that the belt filter press has low efficiency in treating sludge with a particle size below 16 microns and the moisture content of dry sludge is difficult to control. It can assist the belt filter press in specially treating fine particle sludge and improve the solid binding rate of dry sludge.

[0140] At the same time, in order to improve the concentration and flocculation effect of fine particle sludge, the project also developed an additional transfer conditioning tank, added a concentration and flocculation process of fine particle sludge, added flocculation agents to cope with the working conditions of sludge with different particle sizes, and added on-site sampling tests at three mud sampling points in the primary sedimentation tank to distinguish the working conditions and select agents and equipment.

[0141] The details are as follows:

[0142] (1) If it is planned to pump out only the sludge in the front part of the pool, and its particle size is above 20 microns, the normal operation mode will be adopted, that is, the sludge from the primary sedimentation tank will be transported to the sludge concentration tank system 1 for dosing, concentration, sedimentation and flocculation of sludge, and then supplied to the belt filter press unit in the filter press plant for dehydration and consolidation. During this period, chemicals will be added in time to promote the dehydration and consolidation of the belt filter press and improve the efficiency and quality of dry sludge consolidation. Under normal circumstances, only the concentration tank and the belt filter press unit are used for sludge concentration conditioning and filter pressing dehydration and consolidation. The chemicals added to the concentration tank supplied to the belt filter press unit are: 0.5% PAC + 0.05% PAM. The moisture content of the consolidated dry sludge can reach between 45% and 50%, and the thickness of the dry sludge cake can reach 25mm to 35mm. Under the full load operation of 14 groups of concentration tanks and 12 groups of belt filter press units, the construction schedule requirements are met and the quality is up to standard.

[0143] (2) If it is necessary to pump out the sludge at the junction of the front and middle parts of the pool, and the particle size is a mixture of 20 microns or more and 16 microns ≤ ≤ 20 microns, when the sludge particle size is all above 16 microns, 14 sets of concentration tank systems and 12 sets of drug adding box systems (each with 2 independent drug bins) can be connected in series or in groups in parallel to supply the 12 belt filter press units and 6 plate and frame filter press units in the filter press plant to operate at full capacity, and carry out sludge concentration and conditioning, drug adding, mixing and conveying, sludge filtration dehydration and consolidation, dry sludge transmission and transportation, residual water (tail water) purification, resource recovery and utilization, and ecological restoration construction according to the process.

[0144] That is, all particles above 20 microns are filtered and consolidated using 12 belt filter presses, and the reagent added to the concentration tank of the belt filter press is: 0.5% PAC + 0.05% PAM;

[0145] For particles with a diameter of 16 microns or less and a diameter of 20 microns or less, 6 plate-and-frame filter presses are used. The advantages of the two types of equipment are utilized, the efficiency is high, and the dry mud moisture content will not be lower than the design index, and the dry mud cake thickness will not be lower than 20 mm, thus avoiding rework and low efficiency. Of course, on-site sampling test personnel need to increase the frequency of testing and sampling;

[0146] Generally, the particle size in the upper part is above 20 microns, and the particle size in the middle and lower part is 16 microns ≤ ≤ 20 microns. It requires close cooperation between the test personnel and the filter press operator to find the approximate boundary layer of different particle sizes, so that the equipment combination can be changed at any time, and the reagent ratio of the concentration tank and the filter press unit can be adjusted in time to change the mud delivery direction in time.

[0147] When a plate and frame filter press is used to treat fine particle sludge, the reagent added to the concentration tank of the plate and frame filter press is: 0.5% PAC + 0.05% PAM. Two mud concentration and conditioning are required, that is, first concentrated and conditioned once in the concentration tank, and then concentrated and conditioned once in the transfer conditioning tank, and then transported to the plate and frame filter press to fill the mud, and perform filtration, dehydration and consolidation. Therefore, the overall time of the plate and frame filter press is longer than that of the belt filter press, but its treatment quality for fine particles is high. Among them, after optimizing equipment configuration and reagent ratio, the maximum thickness of dry mud filtered by the plate and frame filter press can reach 50mm, and the optimal moisture content of dry mud can reach 40% to 50%, which is 15% to 5% lower than the design index; the thickness of the dry mud cake consolidated by the belt filter press can reach 25mm to 30mm, and the maximum can reach 30mm. The moisture content of dry mud can reach between 45% and 55%, which is about 10% lower than the design index, thereby improving production capacity and effect.

[0148] (3) When the sludge with a particle size of 14.27 microns ≤ ≤ 16 microns in the middle area of ​​the pumped pool is completely concentrated and conditioned twice before being transported to the plate and frame filter press for treatment; however, when the amount of sludge in the middle of the pool is large and the amount of sludge on the surface close to 16 microns is large, the sampling frequency of the sludge in the pool can be increased. The test personnel and the filter press operator need to work closely together to find the approximate boundary layer of different particle sizes, so that the equipment combination can be switched at any time, and then the reagent ratio of the concentration tank and the filter press unit can be adjusted in time, and the direction of sludge transportation can be changed in time, that is, the filter press equipment can be selected according to the actual situation: a part of the sludge with a particle size close to 16 microns can be used for the sample test. After adjusting the reagent ratio and concentrating and conditioning the mud twice in the concentration tank and the transfer conditioning tank, the belt filter press is still used for filtration. At the same time, reagents are added again at the mud inlet end of the belt filter press to promote the mud-medicine reaction and promote dehydration and consolidation, so as to achieve the optimal moisture content of dry mud of 45% to 55% and the thickness of dry mud cake of 20mm to 30mm. For the other part of the bottom mud with a particle size of 14.27 microns ≤ <16 microns, after concentrating and conditioning twice in the concentration tank and the transfer conditioning tank, the plate and frame filter press is used for filtration, so as to achieve the optimal moisture content of consolidated dry mud of 45% to 50% and the thickness of dry mud cake of 35mm to 40mm.

[0149] (4) When there is fine particulate sludge (particle size below 14.27 microns) at the end of the pumping pool, a combination of a concentration tank + a transfer conditioning tank + a plate and frame filter press unit is used. At the same time, the reagent ratio is adjusted, the concentration and flocculation time of the mud and medicine in the concentration tank and the transfer conditioning tank is increased, and the filtration time of the plate and frame filter press unit is increased. The moisture content of the dry mud can be controlled between 40% and 50%, and the optimal mud cake thickness can reach about 30 mm, achieving good work efficiency.

[0150] (5) When the concentration tank, medicine box, transfer conditioning tank or filter press unit needs to be shut down for maintenance in turn, it is possible to plan to select single or multiple concentration tanks, medicine boxes, transfer conditioning tanks or filter press units of different groups to be connected in series or in parallel, and then combine production operations to avoid large-scale shutdowns that delay production progress and meet normal maintenance and overhaul needs; it can also meet the production needs of different working conditions, and by increasing the number of equipment combinations, achieve day and night peak production, adjust the dredging mud volume of Chaohu dredgers, the concentrated mud and water volume of concentration tanks, the mud and water volume of transfer concentration tanks, adjust the mud storage volume of the onshore primary sedimentation tank, flexibly adjust the liquid medicine ratio, the conditioning mud concentration, the conveying volume and speed, so as to facilitate the adjustment and control of the construction period, improve work efficiency and quality, and ensure safe production. Its normal production process is similar to the above two operation modes.

[0151] In the case of rotating shutdowns for maintenance or staggered production adjustments, equipment can be freely combined according to on-site needs. The general principle is: concentration tank + belt filter press unit, concentration tank + transfer tank + plate and frame filter press unit, concentration tank + transfer tank + belt filter press unit. The number of each equipment and facility is at least 1 for 1, or multiple concentration tanks + multiple transfer tanks can correspond to 1 filter press unit, or multiple concentration tanks + multiple transfer tanks can correspond to multiple filter press units.

[0152] The onshore primary sedimentation tank, commonly known as the mud pool, has a floating safety channel for on-site sampling test personnel to take samples. The samplers hold long-handled sampling tubes and can go deep into different water depths to take mud and water samples of different depths. The samples are sealed in sampling bottles and tested in the laboratory. The Malvern laser particle size analyzer (Hydro 2000MU(A)) is used for particle size analysis.

[0153] Example 6

[0154] The sludge from Chaohu Lake is dredged by an environmentally friendly cutter suction dredger and transported to a sludge screening, filtering and diversion device (invention patent: ZL 202221191455.2) via a sludge discharge pipe to an onshore sludge discharge site, which separates the sludge from the garbage. The garbage is temporarily stored and then harmlessly treated, while the separated sludge is discharged from the pipeline at the river and lake sludge input port into the onshore primary sedimentation tank (mud pool), including the geotextile tube bag blowing and filling operation area on the water, and the tail water recovery, purification, sedimentation and flocculation of sludge. That is, the sludge after flocculation is blown and filled with water and solidified by geotextile tube bags, and a total of 300,000 m3 of sludge is treated.

[0155] The geotube bag is made of high-toughness geotechnical materials. The joint strength and permeability must meet the design requirements. The bag has a three-dimensional filtering structure, has the ability of plane water permeability and vertical penetration, can effectively intercept the loss of particles, has long-term durability and UV resistance, and can ensure the safety of sludge filling operations. During the sludge filling, PAM and PAC dehydration aids are added according to the reagent ratio. The moisture content of the solidified dry mud should reach the design standard of less than 50%. The dry mud after dehydration and consolidation is used in situ for the construction of lakeside wetlands. The tail water (residual water) filtered out by the geotube bag is recycled to the tail water sedimentation tank for purification. After the tail water is purified to meet the standards, it is discharged into the Nanfei River and Chaohu Lake Wetland.

[0156] The geotextile tube bags in the water mud discharge yard consolidate the dry mud and recycle it into green planting soil. The lakeside wetlands are shaped in situ, and aquatic plants are planted and benthic animals are released to create a lakeside ecological wetland zone with reeds as the dominant species, purify the water quality and improve the ecological environment.

[0157] The geotextile tube bags in the water mud discharge yard consolidate the dry mud and recycle it into green planting soil. The lakeside wetlands are shaped in situ, and aquatic plants are planted and benthic animals are released to create a lakeside ecological wetland zone with reeds as the dominant species, purify the water quality and improve the ecological environment.

[0158] Considering that the outer ring geotube bag of the water mud field cofferdam will be used as part of the wetland wave-breaking submerged dike after construction, the geotube bag of this part is required to have high strength and UV resistance, and anti-scouring function. The outer ring geotube bag of the mud field cofferdam adopts GT750 type with geotextile lining, and the filling area geotube bag of the water mud field cofferdam adopts GT500 type for cost saving. GT500 type geotube bag should be made of high-toughness geotechnical material, with joint strength ≥85KN / m and permeability Q 50 ≥25L / (m 2 ·s), with a three-dimensional filtering structure, plane permeability and vertical permeability, can effectively intercept particle loss, have long-term durability and UV resistance, and can ensure the safety of filling operations. The geotube bag has two sizes: 61.4m×20m and 61.4m×10m, and its technical index parameters are shown in the following table.

[0159] GT500 Geotube Bag Technical Specifications

[0160]

[0161] Determine the location for laying. When laying, follow the principle of laying from the middle to the sides and from the lower layer to the upper layer. Start laying geotextile tube bags from the center of the water mud discharge site, and then gradually extend them to the surrounding areas. In order to ensure the water-tightness and stability of the cofferdam in the later stage, each tube bag is overlapped by 3 meters when laying geotextile tube bags: the first one presses the second one, the second one presses the third one, and so on. The length of each tube bag depends on the on-site terrain, and the joints are left in the straight section of the embankment. This project uses laminated geotextile tube bags for filling.

[0162] To prevent the tube bag from slipping and shifting during filling, after the bottom tube bag is laid, pine piles are set around the tube bag with an excavator, and the pull rings on the side of the geotextile tube bag are connected and fixed with pine piles with ropes to ensure that the bottom tube bag will not be displaced due to hydraulic floating or strong wind, so as to achieve the purpose of fixing the position of the geotextile tube bag. The upper geotextile tube bag is tied together with the bottom geotextile tube bag that has been filled by the pull rings on both sides for fixing.

[0163] The chemical ratio for geotube bags is: 0.5% PAC + (0.1% ~ 0.2%) PAM;

[0164] Filling the geotextile tube bag includes: connecting the multiple filling ports of the bottom tube bag to the main conveying pipe, and transporting the sludge that has been initially flocculated into a mass through multiple branch pipes to fill the geotextile tube bag at the same time. Each pipeline is equipped with a flow meter and an independent gate valve to ensure the stability of the sludge entering the tube bag. The tube bag arranged at the center of the bottom layer must not be offset at all during filling, otherwise it will cause a great deviation in the filling position of the subsequent tube bag. When filling the bottom layer, use manual treading on the top surface of the bag to rearrange the soil particles and make them compact, ensure uniform and smooth filling, speed up the drainage and consolidation of the bag, wait until the entire tube bag reaches the slurry screen, and leave a certain amount of consolidation and dehydration time.

[0165] After each tube bag is filled, the multiple cuffs of the tube bag should be sealed with geotextile tape. After repeated filling, the bag top elevation and axis deviation of the geotextile tube bag are inspected and accepted. For qualified bags, repeated filling is used until the entire bag is completed to meet the design requirements for cuff sealing.

[0166] When the geotube bag reaches the maximum height of 2.5 meters for the first filling, stop filling and start draining. As the drainage continues to flow out of the bag, the height of the bag continues to decrease, and the second filling begins. This process is repeated until the geotube bag is full, usually 8 to 10 times. In the subsequent filling process, as the solid content of the sludge in the bag increases, the time of each filling is continuously shortened, and the amount of drained water changes. The water collection system around the drained water is recycled into the residual water sedimentation tank. No maintenance is required during the sludge consolidation process. It can basically meet the requirements by being placed in the open air and left to stand for about 30 days.

[0167] In order to save space during the construction process, this project adopts a multi-layer stacking arrangement filling method, that is, the filling and dehydration consolidation of the upper layer of tube bags are carried out after the bottom tube bags meet the filling and dehydration consolidation requirements. Before filling the upper layer of tube bags, use inelastic ropes to fix the tube bags of this layer, and strengthen the encryption and fixation of the bottom tube bags to ensure the stability of the upper and lower tube bags. The upper layer of tube bags should be laid in the middle of the two geotextile tube bags that have been filled in the bottom layer, and should be "staggered" with the bottom tube bags. After the filling of the two closely arranged tube bags on the bottom layer is completed, the gap between the tube bags is filled with geotextile bags to provide a flat foundation for filling the tube bags. The blowing and filling of the tube bags should be carried out in batches to prevent the bags from bursting. The blowing and filling height should be determined by pre-work tests. During the repeated filling process, in order to ensure the fullness of the filling, several tube bags on the bottom layer are carried out alternately at the same time. The operator can use a smooth wooden stick to regularly knock and vibrate the surface of the tube bag to accelerate the silt filtration and volume reduction process. Set up height measurement poles to control the filling elevation, strictly control the maximum safe height of the tube bag filling, and arrange special personnel to measure the filling height, filling flow rate, and filling volume of the tube bag regularly to prevent the tube bag from being squeezed and exploded under the dual limit pressure of filling pressure and silt's own gravity, and fill in the construction records. At the same time, dig ditches inside the tube bag to collect seepage water and drain it out in a centralized manner.

[0168] According to the analysis of the botanical characteristics of plants, the following characteristics are selected: 1. Strong vitality, strong adaptability to the environment, and well-developed root system; 2. Large biomass and rapid growth; 3. Seasonal dormancy; 4. Short growth cycle. When selecting artificial wetland plants, local dominant varieties should be given priority. Commonly used plants in artificial wetlands are divided into: 1. Floating plants, such as water hyacinth and water celery; 2. Plants with stems, bulbs and seeds, such as water lilies, lotus, water chestnuts, and Euryale; 3. Emergent herbaceous plants, such as reeds, water plantains, and cattails. This project selects reeds, an aquatic plant with strong adaptability and well-developed root system, for planting.

[0169] During the construction of planting aquatic plants, due to the stacking of multiple layers of geotextile tube bags in this application, aquatic plants can be directly implanted into the soil. After rapid activation, they are concentrated on the surface soil to adjust the soil pH, improve the survival rate of plants, and add CBM compound probiotics to improve the soil microbial substrate. The usage is 10kg / mu, i.e. 5g / m 2 , the dosage is ten times thinner than that of ordinary plants and diluted into liquid for use, about 60ml / m 2 Aquatic plants do not require basal fertilizer, and topdressing is done with CBM compound probiotics instead of organic fertilizer to avoid water pollution.

[0170] The geotubes are used to form an arc-shaped area beside the river and lake, and are connected to the shore. There are also several rectangular geotubes in the arc-shaped area.

[0171] A layer of geotextile tube bags and imitation wood piles are arranged outside the arc-shaped area, and enclosures are laid outside the wood piles to form a waterway for treatment between the enclosures, geotextile tube bags and imitation wood piles.

[0172] There are several algae collection platforms in the waterway to collect algae caused by eutrophication.

[0173] The treatment area of ​​this application is separated from other areas by fencing to prevent eutrophication in other areas from affecting the treatment area of ​​this application. In addition, the rectangular geotube bags provided in this application can divide the arc-shaped treatment area of ​​this application into several areas again, forming multiple ecological balances. If eutrophication occurs in one area, the impact on other areas is small and can be dealt with in a timely manner.

[0174] If the arc-shaped area is treated, the above operations can be repeated with the arc-shaped area as the shore to continue to treat the lake water in other areas, and gradually expand the treatment of the entire river and lake area and the surrounding water systems, which reduces the difficulty of treatment, and can be divided into areas for easy management and beautiful appearance.

[0175] The site of Example 1-6 is located in the nearshore lake area outside the Nanfei River estuary into Chaohu Lake, distributed between the Nanfei River estuary and the left side of the Chaohu Lake channel, with a total dredging area of ​​5.52 km 2 The dredging depth in the pilot area was 20-50cm, the average dredging depth was about 0.29m, and the total dredging volume was 1.588 million m 3 .

[0176] The project site is equipped with one land-based mud discharge site and one water-based mud discharge site. The mud in the land-based mud discharge site is dehydrated and consolidated using a filter press, and a total of 1.288 million m3 of mud has been treated. 3 The consolidated dry mud was transported to the Guojiashan Mine in Chaohu City for backfilling and ecological restoration. The bottom mud of the water mud field was dehydrated and consolidated using geotextile tube bags, and a total of 300,000 m3 of bottom mud was treated. 3, consolidated dry mud is used in situ for lakeside wetland construction.

[0177] The tail water (residual water) purification treatment project volume is about 14.29 million m3. The tail water (residual water) discharge standard meets the first-level discharge standard in the "Comprehensive Sewage Discharge Standard" (GB8978-1996), that is, SS (suspended solids concentration) <70mg, COD (chemical oxygen demand) <100mg, ammonia helium <15mg, and the pH value should comply with the "Surface Water Environmental Quality Standard" (GB3838-2002). The qualified residual water is discharged to the lakeside wetland and Nanfei River through the wetland pump station.

[0178] The moisture content of solidified dry mud complies with the requirements of the "Standard for Geotechnical Test Methods" (GB / T50123-2019), with the belt filter press being less than 55% and the geotube bag being less than 50%. In addition, during the subsequent storage, transportation, mine restoration, and wetland area construction, it should be ensured that the mud does not turn into mud after being soaked in water.

[0179] Compared with the traditional method, it has the advantages of scientific design, reasonable structural layout, reliable process flow, fast and efficient, safe structure, environmental protection and energy saving, economical and applicable, easy to use, large scale of applicable ecological dredging, large output of conveyed sludge, large amount of sludge treated by cascade sedimentation and flocculation sludge, large amount of tail water purified and clarified, strong integrated production and treatment capacity of various facilities in land sludge field, large amount of environmentally friendly recycling and discharge of qualified tail water, high degree of environmental protection of lakeside wetlands, less dependence on the construction of permanent equipment and facilities, high work efficiency, convenient dosing and spraying, rapid sedimentation and flocculation of sludge, sufficient filtration and interception, good purification and clarification effect, fast speed, low operating cost, simple and safe operation, energy saving and environmental protection, wide application range, etc. It can adapt to the operation requirements of waterside areas, restricted narrow spaces, and cross-operation areas, which is conducive to eliminating safety hazards, can greatly improve construction production efficiency, reduce construction costs, ensure construction safety, and do not produce secondary environmental pollution. It has achieved the goals of green and environmental protection construction in lakeside wetland areas, protecting wetland ecological environment, and saving and environmentally friendly use of water resources, which is in line with the design concept of green buildings advocated by the country. The method of the invention can be widely used in the fields of fully settling and flocculating sludge or sewage sludge in lakes, rivers, wetlands, towns, factories and enterprises, and the like, and can be promoted and applied in similar projects, such as adding chemicals to flocculate the residual water (tail water) after dehydration and solidification, filtering the sedimentation and flocculation sludge, purifying and clarifying the sludge, and recycling it for environmental protection.

[0180] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A river and lake ecological dredging construction method, characterized by: The method comprises the following steps: pre-treating the sludge discharged from land or water during ecological desilting of rivers and lakes, and then performing cascade separation of mud and water and sedimentation and flocculation in a primary sedimentation tank to obtain sedimentation and flocculation sludge and supernatant, and the supernatant enters the sewage treatment system for treatment. The sedimentation and flocculation sludge discharged from land is mechanically filtered, dehydrated and consolidated. The treated sludge is used for mine or pit backfill and ecological restoration, and the sewage is returned to the primary sedimentation tank for treatment; Alternatively, the sedimentation and flocculation sludge discharged from the water is filled with geotube bags for dehydration and consolidation. The treated sludge is used for wetland construction and ecological restoration, and the sewage is returned to the primary sedimentation tank for treatment.

2. A river and lake ecological dredging construction method according to claim 1, characterized in that: The sedimentation and flocculation sludge discharged from the land is subjected to mechanical filtration pressing, dehydration and consolidation, comprising the following steps: sampling in a primary sedimentation tank to obtain coarse sludge, medium coarse sludge, medium sludge and fine sludge; The coarse sludge, medium coarse sludge, medium sludge and fine sludge are respectively concentrated and conditioned, and then filtered to obtain the treated sludge.

3. A river and lake ecological dredging construction method according to claim 2, characterized in that: The coarse sludge is in the front area of ​​the primary sedimentation tank; The medium-coarse sludge is located at the junction of the front and middle parts of the pumping tank; The medium-sized sludge is in the middle area of ​​the primary sedimentation tank, and the fine-particle sludge is the sedimentation flocculation sludge in the terminal area of ​​the primary sedimentation tank; On-site sampling was carried out from the front, middle and rear drainage areas of the pool, and the sludge particle size was measured in the laboratory to provide a basis for the subsequent selection of reagent ratios, concentration conditioning and filter press units; The particle size of coarse sludge is above 20 microns; The particle size of medium-coarse sludge is 16 to 20 microns; The particle size of medium sludge is 14.27 microns to 16 microns; The particle size of the micro-sludge is less than 14.27 microns.

4. A river and lake ecological dredging construction method according to claim 2, characterized in that: The thickening and conditioning of coarse sludge includes adding drugs, thickening, settling and flocculating the coarse sludge in the thickening tank, and then dehydrating and consolidating the coarse sludge through the belt filter press unit. During this period, chemicals are also added to promote the dehydration and consolidation of the belt filter press. The moisture content of the consolidated dry sludge is between 45% and 50%, and the thickness of the dry sludge cake is 25mm to 35mm. And / or, sampling of medium and coarse sludge requires close cooperation between the test personnel and the filter press operator to find the approximate boundary layer of different particle sizes, switch the equipment combination at any time, adjust the reagent ratio of the concentration tank and the filter press unit in time, and change the sludge conveying direction in time; And / or, the medium and coarse sludge concentration treatment and conditioning includes adding medicine to the medium and coarse sludge, concentrating, and settling and flocculating the sludge; and dehydrating and consolidating the sludge by a belt filter press unit and a plate and frame filter press unit, wherein the moisture content of the consolidated dry sludge is between 45% and 50%, and the thickness of the dry sludge cake is between 25mm and 35mm.

5. A river and lake ecological dredging construction method according to claim 4, characterized in that: In step S2, the medium-sized sludge is concentrated and conditioned twice, and then transported to a plate-and-frame filter press unit for treatment; When the proportion of medium-sized sludge with a surface particle size close to 16 microns is greater than 50%, the sampling test frequency of the bottom sludge in the pool should be increased. The test personnel and the filter press operators should work closely together to find the approximate boundary layer of different particle sizes, switch the equipment combination at any time, and then adjust the reagent ratio of the concentration tank and the filter press unit in time, and change the conveying direction of the sludge in time, that is, select the filter press equipment according to the actual situation: A portion of the bottom mud with a particle size close to 16 microns is filtered by a belt filter press after adjusting the reagent ratio and concentrating and conditioning twice in the concentration tank and transfer conditioning tank. At the same time, reagents are added again at the mud inlet end of the belt filter press to promote the mud-drug reaction, which can achieve a dry mud moisture content of 45% to 55% and a dry mud cake thickness of 20mm to 30mm. For the other part of the bottom mud with a particle size of 14.27 microns ≤ <16 microns, after two concentration conditionings of concentration conditioning and transfer conditioning, the plate and frame filter press unit is used for filtration, which can achieve a moisture content of 45% to 50% for the consolidated dry mud and a dry mud cake thickness of 35mm to 40mm; And / or, in step S2, the concentration treatment and conditioning of the particulate sludge includes sequentially performing a concentration tank, a transfer conditioning tank and a plate and frame filter press unit, while adjusting the reagent ratio, increasing the concentration and flocculation time of the mud and medicine in the concentration tank and the transfer conditioning tank, and increasing the filtration time of the plate and frame filter press unit. The moisture content of the dry mud can be controlled between 40% and 50%, and the mud cake thickness can reach 30 mm.

6. A river and lake ecological dredging construction method according to claim 4, characterized in that: The reagent added to the concentration tank of the belt filter press is: 0.5% PAC + 0.05% PAM or 0.09% PAC + 0.15% PAM; And / or, the reagent added to the concentration tank of the plate and frame filter press is: 0.5% PAC + 0.05% PAM; And / or, the reagent ratio of the dosing point of the belt filter press that is supplied multiple times is: 10% PAC + (0.1% to 0.2%) PAM; And / or, the reagent ratio of the mud transfer conditioning tank used in conjunction with the plate and frame filter press is: 10% PAC + (0.1% to 0.2%) PAM.

7. A river and lake ecological dredging construction method according to claim 1, characterized in that: The sedimentation and flocculation sludge of the water discharge is filled with geotextile tube bags for dehydration and consolidation, including filling the sedimentation and flocculation sludge of the water discharge into the geotextile tube bags, injecting flocculation drugs during filling, draining after filling, repeating the filling, adding drugs, and draining steps until the geotextile tube bags are filled, and then standing for consolidation; The leachate tail water is collected and transported to the primary sedimentation tank.

8. A river and lake ecological dredging construction method according to claim 7, characterized in that: Geotextile tube bags filled with sedimentation and flocculation sludge from water discharge are laid beside rivers and lakes. When the bottom tube bag reaches the filling and dehydration consolidation requirements, the upper tube bag is filled and dehydrated; Before filling the upper layer of tube bags, use an inelastic rope to fix the tube bags of that layer; And / or, the upper layer of tube bags should be laid in the middle of the two geotextile tube bags on the bottom layer that have been filled, and the gap between the two closely arranged tube bags on the bottom layer should be filled with geotextile mud; The pipe bag filling should be carried out in batches, and the filling height must be determined by pre-work tests. Several pipe bags on the bottom layer should be carried out alternately at the same time. The operator should use a smooth wooden stick to regularly knock and vibrate the surface of the pipe bag to speed up the sludge filtration and volume reduction process; The geotubes are used to form an arc-shaped area beside the river and lake, and are connected to the shore. There are also several rectangular geotubes on the geotubes. A layer of geotube bags and imitation wood piles are arranged outside the arc area.

9. A river and lake ecological dredging construction method according to claim 7, characterized in that: Geotube bags should be made of high-toughness geotechnical materials, with joint strength ≥85KN / m and permeability Q 50 ≥25L / (m 2 s); And / or, the chemical ratio for geotube bags is: 0.5% PAC + (0.1% to 0.2%) PAM; Planting floating plants, stem, bulb and seed plants, emergent herbaceous plants on the mud; Preferably, the floating plants include water hyacinth and water celery; Preferably, the stem, bulb and seed plants include water lily, lotus, water chestnut and Euryale ferox; Preferably, the emergent herbaceous plants include reeds, water plantains, and cattails.

10. A processing system for a river and lake ecological dredging construction method according to any one of claims 1 to 9, characterized in that: The sludge system for onshore sludge discharge includes a sludge thickening tank system, a dosing tank system, a transfer conditioning tank system, and residual water recovery facilities; The dosing box system is arranged on the filter press unit side of the filter press plant near the dosing box, and the dosing box system, residual water recovery facilities, sludge concentration tank system, and transfer conditioning tank system are arranged in sequence.

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