A method for utilizing sediment resources based on ecological building blocks

Abstract

The present invention discloses a method for resource utilization of sediment based on ecological building blocks. The preparation steps are as follows: Step 1: solidify the sediment as the first layer, specifically by crushing plant straw and spreading it on the bottom, then spreading sediment of different moisture contents on the plant straw, and finally thoroughly mixing the spread sediment with the lower layer of plant straw to obtain solidified sediment; Step 2: compact ordinary clay as the second layer; Step 3: lay a layer of gravel as the third layer; Step 4: lay a layer of planting soil as the fourth layer. The present invention places the treated riverbed sediment into the ecological building blocks to achieve in-situ resource utilization of the sediment. The sediment does not need to be transported outside. The preparation method of the present invention can avoid secondary pollution of the sediment, reduce the cost of sediment treatment, and has good economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of black and odorous water body treatment, and in particular to a method for resource utilization of bottom mud based on ecological building blocks. Background Art

[0002] A large amount of riverbed sediment will be generated during the treatment of black and odorous water bodies and the dredging of stormwater drainage channels. The reduction, harmlessness and resource utilization of these sediments are issues that need to be addressed urgently. At present, ex situ treatment technologies for riverbed sediment are widely used, and the main disposal methods include composting, ocean dumping, sanitary landfill, agricultural greening, etc. Composting treatment uses microorganisms to decompose organic waste to achieve the purpose of sediment treatment. However, composting treatment generally requires a large site and has high transportation and treatment costs. Ocean dumping is a simple and economical disposal method, but it will pollute the ocean and threaten the marine ecosystem. Sanitary landfill is developed on the basis of traditional landfill. Although sanitary landfill has low costs and quick results, it ultimately only delays the time when environmental pollution occurs. Agricultural greening refers to the use of bottom mud for farmland fertilization and greening construction. Bottom mud is rich in various organic nutrients and has a high concentration of organic matter. Therefore, if it can be used reasonably, it can improve soil structure, increase soil fertility, and promote crop growth. However, since bottom mud also contains a large number of harmful components, it will pollute the soil after application, affecting crop production and endangering human health. Therefore, bottom mud must be treated before use, which undoubtedly increases a lot of costs. If the riverbed mud is seriously polluted, the difficulty of treatment will increase, and the application requirements will be difficult to meet. The application of this method will be greatly limited. The above centralized bottom mud disposal methods have the disadvantages of large engineering workload, high treatment costs, secondary pollution, difficulty in subsequent bottom mud treatment, and waste of resources.

[0003] Some patents report on the treatment methods of sediment. CN108164106A discloses a solidification method based on the resource utilization of waste biomass and riverbed polluted sediment. The preparation method includes: 1. using ordinary clay to make a base after compaction, and the thickness is determined according to the moisture content of the riverbed sediment; 2. Selecting crushed rice straw or wheat straw to be spread on the base layer, and the diameter of the spread layer is at least 1 cm smaller than the diameter of the base layer; 3. Spreading riverbed polluted sediment with different moisture contents on the rice straw or wheat straw, and the diameter of the sediment spread is 1 cm. At least 1cm smaller than the diameter of the base layer; 4. Thoroughly mix the paved bottom mud with the lower layer of rice straw or wheat straw, and pile them in the center of the base layer; 5. Cover with a layer of clay and tamp it down. The thickness of the clay layer should be enough to completely cover the mixture of bottom mud and rice straw or wheat straw and leave at least 1cm thick; 6. If you want to increase the overall height of the solidification system, you can also lay a layer of sand and gravel on the base layer; 7. In order to improve the stability of the solidification system, pile a circle of stones around the entire system. However, this method can only store the bottom mud, and cannot realize the resource utilization of the bottom mud. In addition, the above method requires two applications of clay, which is labor-intensive and costly, and needs to be kept out of the rain during subsequent storage.

[0004] Currently, the filling materials of ecological blocks are mainly crushed stone, block stone or pebbles. The preparation of ecological blocks requires the transportation of a large amount of stone from outside, which is costly, and the bottom mud excavated from the river channel needs to be processed ex situ.

[0005] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for resource utilization of sediment based on ecological blocks, in which the sediment is treated in situ and placed in ecological blocks, which not only realizes the resource utilization of sediment, but also facilitates adapting to local conditions and does not cause any pollution to the environment. Summary of the Invention

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for utilizing sediment resources based on ecological blocks is characterized by placing solidified sediment in the first layer within the ecological blocks, then sealing the sediment with a layer of clay, and finally capping with a layer of crushed stone and a layer of planting soil, specifically comprising the following steps:

[0008] Step 1: Solidify the bottom mud as the first layer. The specific operation is as follows: crush the plant straw and spread it on the bottom, then spread the bottom mud with different moisture contents on the plant straw, and finally mix the spread bottom mud with the lower layer of plant straw to obtain the solidified bottom mud;

[0009] Step 2: Tamp ordinary clay as the second layer;

[0010] Step 3: Lay a layer of crushed stone as the third layer;

[0011] Step 4: Spread a layer of planting soil as the fourth layer.

[0012] The compressive strength of the first layer is calculated to be greater than 0.2 MPa based on the maximum pressure it may be subjected to, and the average thickness is 100 mm to 400 mm;

[0013] The average thickness of the second layer is 80mm-120mm;

[0014] The average thickness of the third layer is 60-100 mm;

[0015] The average thickness of the fourth layer is 100-200 mm.

[0016] In one embodiment, the ecological building blocks used are box-shaped ecological building blocks, with only the upper portion of the blocks being open and the remaining surfaces being closed.

[0017] In one embodiment, the cross section of the ecological building block is in an irregular geometric shape or a regular geometric shape, and the regular geometric shape is a rectangle, a square, a trapezoid or a circle.

[0018] In one embodiment, the plant straw is crop straw.

[0019] In one embodiment, the crop straw is one or more of wheat straw, rice straw, corn straw, and sorghum straw, preferably wheat straw, rice straw, and corn straw.

[0020] In one embodiment, the moisture content of the sludge is 35% to 85%.

[0021] In one embodiment, the moisture content of the common clay in step 2 is 19% to 23%.

[0022] In one embodiment, the diameter of the gravel in step 3 is 0.5 to 10 cm.

[0023] In one embodiment, the planting soil in step 4 is loose and fertile, has a moderate acidity and alkalinity, does not contain construction and domestic waste, and is free of toxic substances.

[0024] In one embodiment, the cross-sectional areas of the first layer, the second layer, the third layer and the fourth layer are the same; the average thickness of the first layer is 250 mm, the average thickness of the second layer is 100 mm, the average thickness of the third layer is 80 mm, and the average thickness of the fourth layer is 150 mm.

[0025] The present invention also provides an ecological building block containing bottom mud, which is prepared by any of the above methods.

[0026] Compared with existing sediment treatment and utilization methods, the present invention has the following advantages:

[0027] (1) Plant straw is used as a sediment solidifier, and the sediment is utilized in situ without the need for external transportation and secondary pollution.

[0028] (2) The method for utilizing sediment resources of the present invention is simple and easy to operate in engineering, and can achieve sediment pollution treatment while generating certain economic value.

[0029] (3) Ecological blocks use low amounts of clay and gravel, making them suitable for batch production. Ecological blocks can be used to plant plants and beautify the environment, and can also be used for slope protection, retaining walls, and other projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the front cross-section of the ecological building block after the bottom mud is utilized as a resource.

[0031] Figure 2 This is a photo of the ecological blocks on site after the sludge resource utilization in Application Example 1. DETAILED DESCRIPTION

[0032] Figure 1 This is the front cross-section of the ecological block after the bottom mud is recycled. Figure 1 As shown, 6 represents the outer retaining block of the ecological block, 5 is the limit block, and the typical ecological block is divided into four layers. From bottom to top, the first to fourth layers are 1 bottom mud layer, 2 clay layer, 3 gravel layer and 4 planting soil layer. The bottom mud layer is composed of riverbed mud and plant straw.

[0033] In the bottom mud layer, the moisture content of the bottom mud is 30%-85%. If the moisture content of the bottom mud is lower than 30% or higher than 85%, the bottom mud is difficult to solidify.

[0034] In the bottom mud layer, the amount of bottom mud and straw depends on the moisture content of the bottom mud, the type of straw, and the length of the straw. The mass ratio of bottom mud to straw is 30:1-5:1, preferably 20:1-8:1, and more preferably 18:1-6:1.

[0035] In this invention, ordinary clay refers to clay with a moisture content of 19% to 23%, and the thickness of the clay layer is 80-120mm. Verification has found that if the clay layer is less than 80mm thick, heavy metals in the sediment will precipitate and cause environmental pollution; while a clay layer thicker than 120mm will increase costs.

[0036] Crushed stone, as used herein, refers to broken, hard masses of regular or irregular size, shape, and texture, including common stone and building materials such as clay, crushed concrete, perlite, calcium carbonate, cement granules, construction waste, and slag. The diameter of the crushed stone is 0.5 to 10 cm, preferably 2 to 7 cm, and more preferably 3 to 6 cm. The average thickness of the crushed stone layer is 60 to 100 mm. If the crushed stone layer is too thin, plants will have difficulty surviving, while if it is too thick, costs will increase.

[0037] The planting soil of the present invention refers to loose and fertile soil with moderate acidity and alkalinity, free of construction and domestic waste, and free of toxic substances, which can be used for plant growth and development. The average thickness of the planting soil layer is 100-200 mm.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] In this embodiment, the ecological building block is only open on the top and the rest of the sides are closed. The cross-sectional areas of the first, second, third and fourth layers are the same. Figure 1 As shown in the figure, the specific steps of sediment resource utilization include:

[0041] (1) Crush the rice straw into a 0.2 cm thick layer and spread it on the bottom of the block. Then spread 60% moisture content bottom mud on the rice straw. The ratio of bottom mud to straw is 6:1. The spread bottom mud and straw are fully mixed. After solidification, the compressive strength of the bottom mud layer is greater than 0.25 MPa and the average thickness is 250 mm.

[0042] (2) Cover with a layer of ordinary clay and tamp it to a thickness of 100 mm;

[0043] (3) A layer of crushed stone with a diameter of 3 to 6 cm and an average thickness of 80 mm is laid on the clay layer;

[0044] (4) Finally, spread a layer of planting soil with an average thickness of 150 mm on the gravel layer.

[0045] Example 2

[0046] In this embodiment, the ecological building block is only open on the top and the rest of the surfaces are closed. The cross-sectional areas of the first, second, third and fourth layers are the same. The resource utilization of the bottom mud specifically includes the following steps:

[0047] (1) Crush the wheat straw into 0.5 cm in length and spread it on the bottom of the block. Then spread the bottom mud with a moisture content of 50% on the straw. The ratio of bottom mud to straw is 12:1. The spread bottom mud and straw are fully mixed. After solidification, the compressive strength of the bottom mud layer is greater than 0.3 MPa and the average thickness is 200 mm.

[0048] (2) lay a layer of ordinary clay and tamp it down to an average thickness of 80 mm;

[0049] (3) A layer of crushed stone with a diameter of 3 to 6 cm and an average thickness of 100 mm is laid on the clay layer;

[0050] (4) Finally, spread a layer of planting soil with an average thickness of 100 mm on the gravel layer.

[0051] Example 3

[0052] In this embodiment, the ecological building block is only open on the top and the rest of the surfaces are closed. The cross-sectional areas of the first, second, third and fourth layers are the same. The resource utilization of the bottom mud specifically includes the following steps:

[0053] (1) Crush corn stalks into 1 cm long pieces and spread them flat on the bottom of the blocks. Then spread sludge with a moisture content of 40% on the stalks. The ratio of sludge to stalks is 18:1. The sludge and stalks are thoroughly mixed. After solidification, the compressive strength of the sludge layer is greater than 0.35 MPa and the average thickness is 300 mm.

[0054] (2) lay a layer of ordinary clay and tamp it down to an average thickness of 110 mm;

[0055] (3) A layer of crushed stone with a diameter of 2 to 7 cm and an average thickness of 90 mm is laid on the clay layer;

[0056] (4) Finally, spread a layer of planting soil with an average thickness of 180 mm on the gravel layer.

[0057] Application Example 1

[0058] A river in a certain district of Changzhou City, Jiangsu Province is a heavily polluted river. The river is about 1.8 km long, with an average width of about 15 m and a bottom sediment depth of about 0.3-0.9 m. Due to years of pollution, a large amount of garbage, silt and other pollutants have been deposited at the bottom of the riverbed. These pollutants will affect the water quality of the river in the long term. The approximate dredging volume is 32,700 m 3 In order to restore the water body, it is necessary to carry out dredging projects, and the part of the riverbed mud with a water content greater than 85% should be transported out, and the part with a water content of 35% to 85% can be directly used as the filling material of the ecological building blocks after solidification treatment, so as to realize resource utilization. Based on the method of Example 1, in this application example, about 1000m of riverbed mud is selected. 3 For technical verification, the riverbed mud is treated and used as ecological block filling material to achieve resource utilization. Combined with the construction unit budget comparison, if the existing dredging needs to transport the mud to the disposal point, the longest transportation distance is 76.8km, the average transportation distance is 30km, and the per m 3The unit price of comprehensive transportation of sediment is RMB 53.37. If this part of sediment is desilted and recycled in situ, the transportation cost will be completely saved. However, recycling of sediment will increase the cost of building ecological blocks. This part depends on whether the ecological blocks are built manually or mechanically. The mechanical fee is RMB 2,000 per shift, and each shift can build about 200m of ecological blocks. 3 , per m 3 The cost of masonry machinery is RMB 10; if ecological blocks are constructed manually, each person can build 10m per day. 3 , 200 yuan per person per day, per m 3 The labor cost for masonry is 20 yuan. The cost of loam and bottom clay is estimated at 10 yuan per ton. Excluding the corresponding costs, in-situ sludge resource utilization can reduce costs by approximately 44% to 62% compared to landfill, significantly saving construction costs. Figure 2 This is an on-site photo of the ecological blocks after the sediment resource utilization in this application example. The ecological blocks can protect the river channel and plant plants, effectively improving the environmental quality of the river channel.

[0059] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for utilizing sediment resources based on ecological building blocks, characterized by: Place the solidified bottom mud in the first layer of the ecological block, then seal the bottom mud with a layer of clay, and finally cover it with gravel and planting soil in sequence. The specific steps include the following: Step 1: Solidify the bottom mud as the first layer. The specific operation is as follows: crush the plant straw and spread it on the bottom, then spread the bottom mud with different moisture contents on the plant straw, and finally mix the spread bottom mud with the lower layer of plant straw to obtain the solidified bottom mud; the compressive strength of the first layer is greater than 0.2MPa, and the average thickness is 100mm-400mm; Step 2: Tamp ordinary clay as the second layer, with an average thickness of 80mm-120mm; Step 3: Lay a layer of crushed stone as the third layer. The average thickness of the third layer is 60-100mm. Step 4: Spread a layer of planting soil as the fourth layer. The average thickness of the fourth layer is 100-200mm. The ecological building block is a box-shaped ecological building block, with only the upper part of the building block open and the other sides closed; the cross section of the ecological building block is rectangular or square; The moisture content of the ordinary clay in step 2 is 19% to 23%; The ecological building blocks can be used for planting and growing plants.

2. The method for utilizing sediment resources based on ecological building blocks according to claim 1, characterized in that: The plant straw is crop straw.

3. The method for utilizing sediment resources based on ecological building blocks according to claim 2, characterized in that: The crop straw is one or more of wheat straw, rice straw, corn straw, and sorghum straw.

4. The method for utilizing sediment resources based on ecological building blocks according to claim 3, characterized in that: The crop straw is wheat straw, rice straw or corn straw.

5. The method for utilizing sediment resources based on ecological building blocks according to claim 1, characterized in that: The moisture content of the bottom mud in step 1 is 35% to 85%.

6. The method for utilizing sediment resources based on ecological building blocks according to claim 1, characterized in that: The diameter of the gravel in step 3 is 0.5 to 10 cm.

7. The method for utilizing sediment resources based on ecological building blocks according to claim 1, characterized in that: The planting soil described in step 4 is loose and fertile, with moderate acidity and alkalinity, does not contain construction and domestic waste, and is free of toxic substances.

8. The method for utilizing sediment resources based on ecological building blocks according to claim 1, characterized in that: The cross-sectional areas of the first layer, the second layer, the third layer and the fourth layer are the same; the average thickness of the first layer is 250 mm, the average thickness of the second layer is 100 mm, the average thickness of the third layer is 80 mm, and the average thickness of the fourth layer is 150 mm.

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