Method for remodeling saline-alkali soil ecology through cooperation of multi-source sludge compost and microwaves

Abstract

The invention relates to a method for remodeling saline-alkali soil ecology, in particular to a method for remodeling saline-alkali soil ecology through cooperation of multi-source sludge compost and microwaves. The method aims to solve the problems that an existing saline-alkali soil improvement method is high in cost and serious in water resource waste, secondary salinization of surrounding soil is possibly caused by unsmooth drainage, and the method is difficult to implement in areas lack of fresh water resources. The method comprises the following steps: step 1, analyzing component characteristics of multi-source sludge, and establishing a scientific raw material proportioning model; step 2, piling the pretreated sludge mixture into a strip pile shape, reasonably arranging a microwave emission device and a ventilation pipeline in a pile body, and constructing a microwave-aerobic coupling fermentation environment; and step 3, formulating a microwave enhanced compost application scheme for soil with different saline-alkaline degrees. The invention belongs to the technical field of environmental science and agriculture.

Description

Technical Field

[0001] The invention relates to a method for reshaping saline-alkali land ecology, and belongs to the field of environmental science and agricultural technology. Background Art

[0002] With the acceleration of industrialization and urbanization, the amount of sludge generated by sewage treatment plants is increasing. This sludge comes from a wide range of sources, including domestic sewage, industrial wastewater treatment plants, and river dredging. Domestic sewage sludge has a relatively high organic matter content, but it often contains a large amount of water and is prone to spoilage and odor. Industrial sludge has a complex composition, containing not only some heavy metals but also some special substances with potential biological activity, making it difficult to treat. River sludge has poor physical properties, often being viscous and having poor air permeability. Traditional sludge treatment methods, such as simple landfill, not only occupy a large amount of valuable land resources but are also highly susceptible to secondary environmental problems such as groundwater contamination. Conventional composting technologies, which mostly target sludge from a single source, fail to fully exploit the advantages of different sludge types. Composting efficiency is low, quality varies, and it cannot meet the needs of large-scale, high-quality applications.

[0003] Meanwhile, saline-alkali land, a unique type of land resource, is widespread worldwide. Its high salinity and alkalinity severely inhibit plant growth, significantly reducing its agricultural value. Existing saline-alkali land reclamation methods, such as flooding to remove salt, are costly and wasteful. They can also lead to secondary salinization of surrounding soils due to poor drainage, and are difficult to implement in areas with scarce freshwater resources. While chemical amendments can neutralize soil pH in the short term, long-term use can lead to new problems such as increased soil compaction and chemical residue contamination. Directly applying untreated sewage sludge to soil can damage soil ecosystems and cause soil pollution due to excessive levels of pathogens, heavy metals, and other harmful substances in the sludge. Furthermore, uncomposted sewage sludge decomposes slowly in the soil, preventing it from providing nutrients to plants in a timely manner. It can also burn plant roots due to heat generated by fermentation. Therefore, there is an urgent need to develop new, sustainable saline-alkali land reclamation technologies that effectively utilize waste resources and achieve long-term remediation of saline-alkali land. As an emerging high-efficiency treatment method, microwave technology has demonstrated unique advantages in the fields of material drying, sterilization, and accelerating chemical reactions. Introducing it into sludge composting and saline-alkali land improvement systems is expected to break the existing technical bottleneck. Summary of the Invention

[0004] The present invention aims to solve the problems of existing saline-alkali land improvement methods being high in cost and causing serious waste of water resources, and possibly leading to secondary salinization of surrounding soil due to poor drainage, and being difficult to implement in areas with scarce freshwater resources. A method for collaboratively reshaping the saline-alkali land ecology by combining multi-source sludge composting with microwaves is proposed.

[0005] The technical solution adopted by the present invention to solve the above problems is: the steps of the present invention include:

[0006] Step 1: Analyze the composition characteristics of multi-source sludge and establish a scientific raw material ratio model;

[0007] Step 2: Pile the pretreated sludge mixture into a pile, reasonably arrange the microwave emission device and ventilation pipe in the pile, and build a microwave-aerobic coupled fermentation environment;

[0008] Step 3: Develop microwave-enhanced composting application plans for soils with different salinity levels.

[0009] Furthermore, step 1 specifically includes screening and cultivating a composite microbial flora suitable for a multi-source sludge composting environment, introducing microorganisms with a special stress response mechanism to microwave radiation, accelerating metabolism under a microwave field, and increasing the decomposition rate of organic matter.

[0010] Furthermore, step 2 specifically includes:

[0011] Step 201: Start microwave radiation, adjust the microwave power to the range of 500-1000W, and the frequency to about 2450MHz, and use the penetration, thermal effect, and non-thermal effect of microwaves to promote the high-speed vibration of water molecules in the sludge to generate heat, quickly increase the pile temperature, and activate microbial activity;

[0012] Step 202: Design a microwave-assisted segmented temperature-controlled fermentation system to divide the composting process into three stages: a temperature-raising stage, a high-temperature stage, and a temperature-falling stage.

[0013] Step 203: Equipped with intelligent dynamic compost turning and ventilation equipment, the compost turning frequency and ventilation intensity are automatically adjusted based on real-time monitoring data; during the temperature rise period and high temperature period, the frequency of compost turning is increased to ensure uniform heating of the material and prevent local overheating that causes microbial inactivation, while the ventilation volume is increased to meet the microbial demand for oxygen and promote aerobic respiration metabolism; during the temperature drop period, the compost turning and ventilation operations are reduced to maintain a relatively stable state of the compost and assist in the later maturation of the compost.

[0014] Furthermore, step 3 specifically includes:

[0015] For slightly saline-alkali land, use low-dose, high-nitrogen, phosphorus and potassium content and microwave-pretreated compost for surface application. At the same time, use microwave equipment to moderately irradiate the surface soil. Set the microwave power in the range of 300-800W, the frequency of about 2450MHz, and the irradiation time for 5-15 minutes. This will promote the more efficient integration of nutrients in the compost into the soil. At the same time, the electromagnetic field stimulation of microwaves can promote the germination and rooting growth of early vegetation seeds.

[0016] For moderately saline-alkali land, increase the amount of compost applied and combine deep plowing technology to evenly mix the compost into the deep soil layer. Then, irradiate the plowed soil area with microwaves. Adjust the microwave power to 500-1000W and irradiate for 10-20 minutes. By leveraging the thermal and non-thermal effects of microwaves, the fusion of compost humus and soil is accelerated, further neutralizing alkalinity, optimizing soil structure, and expanding space for plant root growth.

[0017] For severely saline-alkali land, preliminary pretreatment such as land leveling and construction of irrigation and drainage facilities is carried out first. Then, compost rich in salt-alkali-tolerant microorganisms and high humic acid is precisely applied in furrows or holes. The planting area is deeply irradiated with microwaves using a high power of 800-1500W and an irradiation time of 15-30 minutes to target the reduction of soil salinity and build a microenvironment suitable for plant growth. At the same time, the activity of salt-alkali-tolerant microorganisms in the compost is activated to enhance its effect on soil improvement.

[0018] Furthermore, the specific steps include:

[0019] Step 4: Construct a comprehensive saline-alkali land ecological restoration system with microwave-assisted sludge composting improvement as the core.

[0020] Furthermore, in step 1, the sludge ratio is 40-60% domestic sludge, 20-30% industrial sludge, and 10-20% river sludge.

[0021] Furthermore, the temperature of the pile during the high temperature period is 55-65°C and lasts for no less than 7 days.

[0022] Furthermore, the entire process in step 2 lasts for 25-35 days.

[0023] Furthermore, the deep plowing depth in step 3 is 30-40 cm.

[0024] The beneficial effects of the present invention are:

[0025] 1. This invention, with its innovative design that uses microwave technology throughout the entire process, demonstrates significant advantages in multiple dimensions in the field of sludge composting to improve saline-alkali land;

[0026] 2. In the sludge treatment process, the full involvement of microwaves accelerates sludge drying, effectively reduces water content, inhibits the corruption of domestic sludge, and promotes the transformation of special substances in industrial sludge. It significantly improves the permeability of river sludge, greatly improves the efficiency and quality of multi-source sludge collaborative treatment, significantly reduces the risk of sludge pollution to the environment, and reduces treatment costs. Microwave radiation forms a close synergistic relationship with composting microorganisms, significantly shortening the composting cycle by 5-10 days, quickly producing high-quality compost, and timely supplying abundant and inexpensive organic materials for saline-alkali land improvement, reducing improvement costs and time costs.

[0027] 3. When microwaves are used to improve saline-alkali land, they can not only accelerate the integration of compost nutrients into the soil, improve soil fertility, optimize soil structure, and reduce salinity, but also stimulate plant seed germination and root growth, enhance plant resistance to salinity and alkali, maintain soil fertility for a long time, and promote the accelerated recovery and stability of saline-alkali land ecosystems;

[0028] 4. Compared with chemical improvement methods, the present invention completely avoids the problems of soil compaction, microbial community destruction and secondary pollution caused by chemical improvers, fully complies with the concept of ecological environmental protection, and provides an innovative example for sustainable agriculture and ecological restoration. DETAILED DESCRIPTION

[0029] Specific embodiment 1: A method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves, comprising the following steps:

[0030] Step 1: Analyze the composition and characteristics of sludge from various sources, including domestic, industrial, and river sources, and establish a scientific raw material ratio model. Screen and cultivate a composite microbial community suitable for multi-source sludge composting environments, including conventional functional microorganisms such as efficient cellulose decomposing bacteria, high-temperature and salt-tolerant bacteria, nitrogen-fixing bacteria, and phosphate-solubilizing bacteria. Introduce microorganisms with special stress response mechanisms to microwave radiation to accelerate metabolism and increase the decomposition rate of organic matter under the microwave field.

[0031] Step 2: Pile the pretreated sludge mixture into strips, and rationally arrange the microwave emitting device and ventilation pipes in the pile to build a microwave-aerobic coupled fermentation environment. Start the microwave radiation, adjust the microwave power in the range of 500-1000W, and the frequency of about 2450MHz. Utilize the penetration, thermal effect and non-thermal effect of microwaves to promote the high-speed vibration of water molecules inside the sludge to generate heat, quickly increase the temperature of the pile, and activate the activity of microorganisms at the same time. Compared with traditional composting heating, the heating period can be shortened to 1-2 days, and the temperature of the pile can be rapidly raised to 40-50°C, activating the activity of various microorganisms.

[0032] A microwave-assisted, staged, temperature-controlled fermentation system was designed, meticulously dividing the composting process into three phases: a warming phase, a high-temperature phase, and a cooling phase. The high-temperature phase, maintained at a strict temperature of 55-65°C and lasting at least seven days, utilizes microwaves to enhance microbial metabolism, effectively decomposing and transforming large amounts of macromolecular organic matter and essentially eliminating pathogens and weed seeds. The cooling phase slowly lowers the temperature, stabilizing the microbial community and further maturing the compost. The entire composting process lasts 25-35 days, 5-10 days shorter than traditional processes.

[0033] Equipped with intelligent dynamic compost turning and ventilation equipment, the system automatically adjusts the frequency of turning and ventilation intensity based on real-time monitoring data such as compost temperature, oxygen content, and humidity. During rising and high-temperature periods, the frequency of turning is appropriately increased to ensure even heating of the material and prevent local overheating that can inactivate microorganisms. Ventilation is also increased to meet microbial oxygen needs and promote aerobic respiration and metabolism. During cooling periods, turning and ventilation are reduced to maintain a relatively stable compost state and facilitate the maturation of the compost.

[0034] Step 3. Develop microwave-enhanced compost application plans for soils with different salinity levels. For slightly saline-alkali land, use low-dose, high-nitrogen, phosphorus, and potassium content compost that has been pre-treated with microwaves for surface application. At the same time, use microwave equipment to moderately irradiate the surface soil. Set the microwave power in the range of 300-800W, the frequency of about 2450MHz, and the irradiation time of 5-15 minutes to promote more efficient integration of nutrients in the compost into the soil. At the same time, the electromagnetic field stimulation of microwaves can promote the germination and rooting growth of early vegetation seeds. For moderately saline-alkali land, increase the amount of compost application, combine it with deep plowing technology, mix the compost evenly into the deep soil layer, and then irradiate the plowed soil area with microwaves. Adjust the microwave power to 500-1000W and the irradiation time to 1. 0-20 minutes, with the help of the thermal and non-thermal effects of microwaves, the fusion of compost humus and soil is accelerated, the alkalinity is further neutralized, the soil structure is optimized, and space for plant root growth is expanded; for severely saline-alkali land, preliminary pretreatment such as land leveling and irrigation and drainage facility construction is carried out first, and then the compost rich in salt-alkali-tolerant microorganisms and high humic acid is accurately placed in the form of strip furrow application or hole application, and the planting area is deeply irradiated with microwaves. A high power of 800-1500W is used, and the irradiation time is 15-30 minutes. This can target the reduction of soil salinity and alkalinity, build a microenvironment suitable for plant growth, and activate the activity of salt-alkali-tolerant microorganisms in the compost to enhance its effect on soil improvement.

[0035] Step 4: Build a comprehensive saline-alkali land ecological restoration system centered around microwave-assisted sludge composting. Building on the soil improvement through composting, carefully selected saline-alkali-tolerant plants, such as Suaeda salsa, Sesbania sesbania, and Lycium barbarum, are planted. The physiological properties of plant roots, such as soil cuttings, nitrogen fixation, and salt secretion, further consolidate the soil improvement results. Simultaneously, by creating a suitable habitat, insects, birds, and other organisms are attracted to inhabit and reproduce, gradually restoring the ecological diversity of the saline-alkali land and forming a self-sustaining, virtuous cycle ecosystem.

[0036] Wherein, the sludge ratio in step 1 is 40-60% domestic sludge, 20-30% industrial sludge, and 10-20% river sludge;

[0037] The temperature of the pile during the high temperature period is 55-65℃ and lasts for no less than 7 days;

[0038] The entire process in step 2 lasts 25-35 days;

[0039] The deep plowing depth in step 3 is 30-40cm.

[0040] Example

[0041] Example 1

[0042] (1) Collect domestic sludge, industrial sludge and river silt from domestic sewage treatment plants. Component analysis shows that the organic matter content of domestic sludge is about 50%, but the water content is as high as 80%; industrial sludge contains a certain amount of heavy metals such as zinc and copper, and the organic matter content is about 30%; river silt has a heavy texture and very poor air permeability. In view of these characteristics, it is initially set that domestic sludge accounts for 50%, industrial sludge accounts for 25%, and river silt accounts for 15%. The remaining 10% is an auxiliary component for regulating the properties of the material. At the same time, an appropriate amount of composite microbial flora is introduced, and a small fermentation device is used for composting experiments. During the composting process, the microwave power is adjusted to 1000W during the heating period, the initial moisture content of the material is 60%, and the ventilation volume is 0.5m per minute. 3 The temperature of the pile rose rapidly to 45°C within 2 days, activating microorganisms. The temperature was strictly controlled at 60°C during the subsequent high-temperature period, which lasted for 8 days, allowing a large amount of macromolecular organic matter to be decomposed and transformed. For slightly saline-alkali land, the prepared compost was spread on the surface at a rate of 100g per pot, and salsa seedlings were planted. Subsequently, a microwave device with a power of 500W and a frequency of 2450MHz was used to irradiate the soil surface for 10 minutes. After two months of observation, it was found that the plant height of the salsa seedlings was 15 cm higher than that of the control group on average, and the root system was more developed. This preliminarily verified the improvement effect of the microwave-assisted composting scheme on slightly saline-alkali land and its role in promoting plant growth.

[0043] Example 2

[0044] (1) Collect domestic sludge, industrial sludge and river silt from domestic sewage treatment plants. The organic matter content of domestic sludge is about 48% and the water content is 78%; the industrial sludge has complex composition, high heavy metal content, and organic matter content of about 28%; the organic matter content of river silt is only 12%. It was finally determined that domestic sludge accounts for 45%, industrial sludge accounts for 25%, river silt accounts for 10%, and auxiliary components account for 20%. At the same time, an appropriate amount of complex microbial flora was introduced. Using a small fermentation device, the microwave power was adjusted to 800W during the heating period, the initial moisture content of the material was 58%, and the ventilation volume was 0.45m per minute. 3The temperature of the pile rose to 43°C within two days, activating microorganisms. The high-temperature period was maintained at 58°C for seven days to ensure pathogen destruction. For moderately saline-alkali land, compost was prepared and mixed with soil at a rate of 200g per pot. After 35cm of simulated deep plowing, the compost was placed in pots and planted with Sesbania sesbania seedlings. The soil was then irradiated with 800W, 2450MHz microwaves for 15 minutes. Two months later, the survival rate of the Sesbania sesbania seedlings reached 80%. Soil testing showed a decrease in salinity and alkalinity, and improved soil structure.

[0045] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves, characterized in that: The specific steps include: Step 1: Analyze the composition characteristics of multi-source sludge and establish a scientific raw material ratio model; Step 2: Pile the pretreated sludge mixture into a pile, reasonably arrange the microwave emission device and ventilation pipe in the pile, and build a microwave-aerobic coupled fermentation environment; Step 3: Develop microwave-enhanced composting application plans for soils with different salinity levels.

2. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: Step 1 specifically includes screening and cultivating a composite microbial community suitable for a multi-source sludge composting environment, introducing microorganisms with a special stress response mechanism to microwave radiation, accelerating metabolism under the microwave field, and increasing the decomposition rate of organic matter.

3. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: Step 2 specifically includes: Step 201: Start microwave radiation, adjust the microwave power to the range of 500-1000W, and the frequency to about 2450MHz, and use the penetration, thermal effect, and non-thermal effect of microwaves to promote the high-speed vibration of water molecules in the sludge to generate heat, quickly increase the pile temperature, and activate microbial activity; Step 202: Design a microwave-assisted segmented temperature-controlled fermentation system to divide the composting process into three stages: a temperature-raising stage, a high-temperature stage, and a temperature-falling stage. Step 203: Equipped with intelligent dynamic compost turning and ventilation equipment, the compost turning frequency and ventilation intensity are automatically adjusted based on real-time monitoring data; during the temperature rise period and high temperature period, the frequency of compost turning is increased to ensure uniform heating of the material and prevent local overheating that causes microbial inactivation, while the ventilation volume is increased to meet the microbial demand for oxygen and promote aerobic respiration metabolism; during the temperature drop period, the compost turning and ventilation operations are reduced to maintain a relatively stable state of the compost and assist in the later maturation of the compost.

4. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: Step 3 specifically includes: For slightly saline-alkali land, use low-dose, high-nitrogen, phosphorus and potassium content and microwave-pretreated compost for surface application. At the same time, use microwave equipment to moderately irradiate the surface soil. Set the microwave power in the range of 300-800W, the frequency of about 2450MHz, and the irradiation time for 5-15 minutes. This will promote the more efficient integration of nutrients in the compost into the soil. At the same time, the electromagnetic field stimulation of microwaves can promote the germination and rooting growth of early vegetation seeds. For moderately saline-alkali land, increase the amount of compost applied and combine deep plowing technology to evenly mix the compost into the deep soil layer. Then, irradiate the plowed soil area with microwaves. Adjust the microwave power to 500-1000W and irradiate for 10-20 minutes. By leveraging the thermal and non-thermal effects of microwaves, the fusion of compost humus and soil is accelerated, further neutralizing alkalinity, optimizing soil structure, and expanding space for plant root growth. For severely saline-alkali land, preliminary pretreatment such as land leveling and construction of irrigation and drainage facilities is carried out first. Then, compost rich in salt-alkali-tolerant microorganisms and high humic acid is precisely applied in furrows or holes. The planting area is deeply irradiated with microwaves using a high power of 800-1500W and an irradiation time of 15-30 minutes to target the reduction of soil salinity and build a microenvironment suitable for plant growth. At the same time, the activity of salt-alkali-tolerant microorganisms in the compost is activated to enhance its effect on soil improvement.

5. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: The specific steps also include: Step 4: Construct a comprehensive saline-alkali land ecological restoration system with microwave-assisted sludge composting as the core.

6. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: The sludge ratio in step 1 is 40-60% domestic sludge, 20-30% industrial sludge, and 10-20% river sludge.

7. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: The temperature of the pile during the high temperature period is 55-65℃ and lasts for no less than 7 days.

8. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: The entire process in step 2 lasts 25-35 days.

9. The method for reshaping saline-alkali land ecology by synergistically combining multi-source sludge composting and microwaves according to claim 1, characterized in that: The deep plowing depth in step 3 is 30-40cm.