Saline-alkali land field treatment and reconstruction system

Abstract

The utility model discloses a kind of saline-alkali soil field management reconstruction systems, and the technical problem of waste water source in the existing saline-alkali soil management technology needs to be periodically to saline-alkali soil to pour fresh water and press salt, the saline-alkali soil field management reconstruction system, including saline-alkali water field device, saline-alkali water field device includes water distribution pipe network and multiple buried drip irrigation pipes, buried drip irrigation pipe is used to set in the surface layer below of the saline-alkali soil to be managed, the water outlet of water distribution pipe network is respectively communicated with buried drip irrigation pipe, the water inlet of water distribution pipe network is used to receive the fresh water obtained after saline-alkali water is desalinated, using the saline-alkali soil field management reconstruction system proposed by the utility model, water resources can be greatly saved;And by constantly water distribution below ground, it can inhibit saline-alkali water to be penetrated to tillage layer by soil capillary hole, and saline-alkali water can be constantly desalinated, so that saline-alkali soil is radically managed.

Description

[0001] This utility model belongs to the field of saline-alkali land improvement technology, and specifically relates to a saline-alkali land return-to-field treatment and improvement system. Background Technology

[0002] When the salt content in the soil affects the normal growth of crops, such land is called saline-alkali land. According to incomplete statistics from UNESCO and FAO, the global area of ​​saline-alkali land is 950 million hectares, of which 99.13 million hectares are in my country. The formation of alkaline and alkalized soils in my country is mostly related to the accumulation of carbonates in the soil, resulting in generally high alkalinity. In severely saline-alkali soil areas, plants can hardly survive, making it impossible to effectively utilize land resources. Furthermore, the high salt and alkali content in the soil makes it difficult for plants to grow normally, leading to long-term soil desertification. Therefore, countries around the world have increased their efforts to manage saline-alkali land. Currently, the management of saline-alkali land mainly includes the following saline-alkali land restoration and transformation system: In the initial stage of improvement, the focus should be on improving soil moisture. This is generally carried out in several steps: first, draining and leaching salt to reduce soil salinity; then planting salt-tolerant plants to enrich the soil; and finally planting crops. Specific improvement measures include: drainage, irrigation to leach salt, siltation, rice planting, soil enrichment, land leveling, and chemical improvement. The amount of water discharged should be carefully controlled. The above-mentioned saline-alkali land return and transformation system requires the pre-drainage of the saline-alkali water from the soil, followed by irrigation with clean water to wash away the salinity. Therefore, this process requires the discharge of a large amount of saline-alkali water and the injection of a large amount of fresh water, which is a waste of water resources and also requires high labor costs.

[0003] The formation of saline-alkali land is mainly related to shallow groundwater. Because groundwater occupies the shallow geological space of the strata, it hinders the accumulation of atmospheric precipitation and surface freshwater. Therefore, through long-term evaporation and concentration, it becomes the root cause of soil salinization. Soil salinization results in a large amount of low-yield farmland and land abandonment, rendering large areas of land resources unusable. Therefore, research is needed on technologies suitable for the transformation of shallow saline-alkali land, replacing saline water with freshwater and recycling it. This not only solves the problem of drought and water shortage but also addresses the root causes of salinization, restoring the development and utilization value of shallow saline-alkali land. For example, Chinese utility model patent with patent number 201710568054.1 and authorization announcement number 107653931 discloses a saline-alkali land transformation system and a saline-alkali land return-to-field treatment and transformation system. The system includes a shallow water level well, a water collection well, a water collection pipe, a water return pipe, a pump pipe, an ejector, and a water collection pipe. The water collection pipe and the water return pipe are connected to the water collection well. The pump pipe is installed in the water collection well. The lower end of the pump pipe is connected to a submersible electric pump, and the upper end of the pump pipe is connected to the inlet of the ejector. The water inlet of the ejector is connected to the water collection pipe via a tee, and the other end is connected to the water collection pipe leading to the shallow water level well. The outlet of the ejector is connected to the water return pipe. The aforementioned system and the saline-alkali land restoration system utilize shallow wells to draw water from the ground through a series of collection and return pipes, employing a siphon effect combined with negative pressure to collect the water in a collection well. The water in the collection well is then pumped out and reinjected into the shallow well to dilute the groundwater, thus providing irrigation for large areas of farmland. While this saline-alkali land restoration system can solve the problem of insufficient freshwater for plant growth, it cannot fundamentally address the issue of saline-alkali land. This is because the salt and alkali remain underground, and saline water will still periodically seep into the topsoil through soil capillaries, requiring regular freshwater irrigation to suppress the salt, which represents a significant waste of freshwater resources. Utility Model Content

[0004] The purpose of this invention is to address the technical problem of existing saline-alkali land treatment technologies requiring regular irrigation with fresh water to suppress salt, which wastes water resources, and to provide a saline-alkali land return-to-field treatment and transformation system.

[0005] The technical solution to the technical problem solved by this utility model is as follows: A system for treating and transforming saline-alkali land by returning it to the field includes a saline-alkali water returning device. The saline-alkali water returning device includes a water distribution network and multiple buried drip pipes. The buried drip pipes are installed below the surface layer of the saline-alkali land to be treated. The outlet end of the water distribution network is connected to the buried drip pipes, and the inlet end of the water distribution network is used to receive fresh water obtained after the saline-alkali water has been desalinated. The saline-alkali water returning device also includes a pressure stabilizing tank, which has a water storage tank body. The water inlet of the tank body is used to receive fresh water, and the water outlet is connected to the water inlet of the water distribution network. It also includes a saline desalination device, which desalinates saline water to obtain concentrated brine and fresh water. The saline desalination device includes a reverse osmosis device, which converts saline water into concentrated brine and fresh water. Its concentrated brine outlet is connected to a concentrated brine tank, and its fresh water outlet is connected to the inlet of a pressure stabilizing tank. The saline water desalination device also includes a filtration device to filter impurities in the saline water. The saline-alkali water desalination device also includes a filtration device to filter impurities in the saline-alkali water. The filtration device includes a quartz sand filter, an activated carbon filter, and a precision filter. The inlet of the quartz sand filter is connected to the outlet of the water pump, and its outlet is connected to the inlet of the activated carbon filter. The outlet of the activated carbon filter is connected to the inlet of the precision filter, and the outlet of the precision filter is connected to the inlet of the reverse osmosis unit. The concentrated water outlet of the reverse osmosis unit is connected to the inlet of the concentrated brine tank, and the clear water outlet of the reverse osmosis unit is connected to the inlet of the fresh water tank. The inlet of the water pump is connected to the saline-alkali water to be treated. It also includes a saline water collection device, which collects and contains saline water in the saline land, and the water inlet of the water pump is located inside the saline water collection device. It also includes a saline water tank, which is located between the water pump and the saline water collection device; A booster pump is installed between the saline water tank and the filter device, and a high-pressure pump is installed between the outlet of the filter device and the reverse osmosis device. The pressure stabilizing tank has an air vent that connects it to the outside atmosphere.

[0006] The advantages and beneficial effects of this utility model are as follows: The saline-alkali land restoration and transformation system proposed in this utility model can greatly save water resources by precisely delivering fresh water to the saline-alkali land using micro-infiltration irrigation technology. Moreover, by delivering fresh water to the soil surface through micro-infiltration technology, it can prevent the movement of saline-alkali water from the ground surface to the surface. The fresh water layer in the cultivated soil is below the surface, which greatly reduces water evaporation and significantly reduces the amount of fresh water used. Furthermore, by continuously distributing water below the surface, it can inhibit saline-alkali water from seeping into the cultivated layer through soil capillaries, thus continuously desalinating the saline-alkali water and fundamentally treating the saline-alkali land.

[0007] This invention relates to a system for treating and transforming saline-alkali land by returning it to the soil. A saline-alkali water desalination device is used to treat the saline-alkali water, and the desalinated water is then delivered to underground drip irrigation pipes. The required fresh water does not need to be replenished from outside sources; the system converts the existing saline-alkali water into fresh water and removes the salt through the main unit of the equipment. Therefore, the salt content of the saline-alkali water beneath the surface will gradually decrease with continuous water use, thus fundamentally treating the saline-alkali land. Attached Figure Description

[0008] Figure 1 This is a block diagram of the saline-alkali land return-to-field treatment and transformation system of this utility model; Figure 2 A block diagram of the saline-alkali water desalination device in a saline-alkali land return and treatment system. Detailed Implementation

[0009] The present invention will be further described in detail below through specific embodiments. The following embodiments are only descriptive and not limiting, and should not be used to limit the protection scope of the present invention.

[0010] like Figure 1 and Figure 2As shown in the figure, the saline-alkali land return-to-field treatment and transformation system of this utility model includes a saline-alkali water raw water collection device, a saline-alkali water desalination device, and a freshwater return-to-field device. The saline-alkali water raw water collection device serves as the raw water intake point. The saline-alkali water desalination device is connected to the saline-alkali water raw water collection device via a water pump. The inlet of the water pump is connected to the inner cavity of the saline-alkali water raw water collection device, and the outlet of the water pump is connected to the inlet of the saline-alkali water desalination device. The saline-alkali water desalination device's saline-alkali outlet is connected to a concentrated brine tank, or it can be directly connected to a concentrated brine tank. The inlet of the drying device is connected to the concentrated brine drying device, which dries the concentrated brine. The concentrated brine drying device can be an automatic evaporation device. The outlet of the concentrated brine drying device is connected to a salt tank or other container. Alternatively, an agricultural brine tank can be installed below to collect and store the separated concentrated brine. The concentrated brine is then evaporated by an evaporation device to obtain dry salt. The outlet of the brine desalination device is connected to the inlet of the freshwater tank, and the outlet of the freshwater tank is connected to the inlet of the freshwater return-to-field device. The freshwater return system employs a buried irrigation system, which includes a water distribution network and buried drip pipes. These drip pipes are buried below the surface layer, with their outlets located within the inner layer of the saline-alkali soil. This allows the returned water to seep into the subsurface of the saline-alkali land. Multiple buried drip pipes are installed in a single treatment area, connected to the outlet of the saline-alkali water desalination device via the water distribution network. The buried depth of the drip pipes is designed to prevent evaporation of the seeping water, and the spacing between them is designed to ensure even water distribution and coverage within the treatment area. Generally, the pipes are located 300-400 mm below the surface layer, with a spacing of 500-800 mm. The resulting freshwater, after infiltration, can dissolve the residual salts and alkalis in the soil, causing them to collect from the underground soil into the saline-alkali water collection device, facilitating further treatment of the saline-alkali land. Freshwater seeping below the surface layer permeates upwards, downwards, left, and right due to osmosis, ensuring moisture even below the surface soil. This water absorbs salts and alkalis from the soil, dissolving them in the water. In this novel saline-alkali land reclamation system, the raw saline-alkali water is treated by a desalination device to obtain freshwater that meets pure water standards or has a salinity comparable to natural water sources. When this water is reinjected into the soil below the surface, its salinity reaches the standards of pure water or natural water sources, making it available for plant absorption and utilization, providing them with better living conditions than before. The reinjected freshwater further dissolves soil salts and alkalis, allowing them to enter the water and preparing for the next cycle of salt and alkali separation.This invention employs buried drip irrigation pipes to return freshwater, treated by a saline-alkali desalination device, to the underground soil. Therefore, no external water resources are needed. Because it utilizes micro-infiltration irrigation technology below the surface for freshwater return, very little water is required. This allows for uniform wetting of the underground soil, dissolving fertilizers for plant absorption. Thus, no external water source is needed, making it extremely convenient and beneficial for the treatment of saline-alkali land in arid and water-scarce areas. This saline-alkali land return and treatment system is also applicable to the treatment of saline-alkali land in arid regions. For saline-alkali land in arid regions, where raw saline-alkali water is scarce or unavailable, underground micro-infiltration irrigation technology can be used to first introduce freshwater transported from outside into the surface layer of the saline-alkali land. This dissolves the saline-alkali in the water, which is then collected in a saline-alkali water collection device and treated by a saline-alkali water desalination device. In this way, saline-alkali land in arid regions can be treated, achieving complete remediation with minimal water resources. Even more advantageously, since the obtained freshwater permeates below the surface layer through buried drip irrigation pipes, water evaporation is reduced. Especially when buried below the surface layer at depths where evaporation is impossible (typically 300-400 mm or less), it essentially does not participate in evaporation. Therefore, the salt and alkali that are dissolved again into the freshwater will not form saline-alkali soil. Instead, they will collect at the water intake point and be separated and desalinated again through a saline-alkali water desalination device. This ensures that the salinity of the treated area only decreases and does not increase. In particular, when crops are planted in the treated saline-alkali land, the addition of fertilizers or pesticides to the freshwater will prevent the formation of saline-alkali soil because the fertilizers and pesticides are introduced below the surface with the freshwater and the water does not evaporate. Thus, the treated land can be prevented from becoming saline-alkali again, allowing the treatment of saline-alkali land to enter a virtuous cycle and achieve a thorough transformation of the saline-alkali land. The start-up time of the freshwater return-to-field device can be controlled according to process requirements. For example, when planting is required in this area, the soil needs to contain nutrients and moisture. When the raw saline-alkali water in the treatment area has been collected and no new raw saline-alkali water seeps into the collection device or the amount of seepage is very small, freshwater return-to-field injection is carried out. During the return-to-field injection, the raw saline-alkali water collection device is backfilled to prevent the backflow of salt and alkali. When planting is not required in this area or the planted plants are drought-resistant varieties, the raw saline-alkali water can be desalinated and returned to the field at the same time. This is like cyclic washing of the land, which can improve the efficiency of saline-alkali land treatment. Moreover, crops can absorb a certain amount of salt and alkali as fertilizer, further reducing the salt and alkali content of the saline-alkali land. Ideally, a pressure stabilizing tank should be installed in the system. The inlet of the pressure stabilizing tank should be connected to the outlet of the freshwater tank, and its outlet should be connected to the inlet of the water distribution network. The tank body of the pressure stabilizing tank should be equipped with an air vent to connect with the outside atmosphere, so that the water in the pressure stabilizing tank is at normal pressure and the pressure stabilizing tank can store freshwater.The pressure stabilizing tank preferably adopts the structure of the water and fertilizer supply device described in the patent application CN 202410558412.0 and publication number CN118216333A, entitled "An Adaptive Water and Fertilizer Supply Device and Adaptive Water and Fertilizer Supply System". Of course, a conventional pressure stabilizing tank structure can also be used, which can provide pressure and water to the buried drip irrigation pipe.

[0011] In this utility model's saline-alkali land restoration and transformation system, after the first saline-alkali water desalination treatment and fresh water return to the field, planting can begin on the land. In the first year, salt-tolerant plants are planted. Due to the saline-alkali water desalination treatment, the pH value of the saline-alkali soil will be reduced to 7.1-8.5, greatly improving the crop growth environment. Alternatively, a saline-alkali land can be treated by collecting saline-alkali water and desalinating it multiple times to meet the normal growth conditions for plants before planting.

[0012] In this utility model's saline-alkali land restoration and transformation system, the saline-alkali water collection device can be a collection well, collection pit, or collection ditch. The collection device is installed in the area requiring saline-alkali treatment, with its bottom below the surface layer, generally located about 2-10 meters below the surface, in the shallow strata. Multiple saline-alkali water collection devices can be set up as water intake points in a single treatment area. The saline-alkali water in the treatment area is collected into the collection device through natural infiltration. This method is relatively economical. Typically, a treatment area will have a low-lying area with accumulated water; setting up a saline-alkali water collection device at this location is ideal. This method is particularly suitable for desertified saline-alkali land, where the natural collection rate of saline-alkali water is relatively fast. After the raw saline-alkali water is collected in the raw saline-alkali water collection device, it is pumped to the saline-alkali water desalination device. The saline-alkali water desalination device can adopt the structure of existing seawater salt extraction devices and seawater desalination devices, such as those named coastal saline-alkali land transformation and seawater desalination devices. It can also adopt reverse osmosis devices in the field of water treatment, such as reverse osmosis membrane separation devices or nanofiltration membrane separation devices, as long as it can separate salt and alkali from water. Ideally, the raw saline water should be filtered before reverse osmosis treatment. A filter should be installed before the reverse osmosis unit. The filtered raw saline water then enters the reverse osmosis unit for solid-liquid separation, preventing clogging. The filter can be a combination of a quartz sand filter, an activated carbon filter, and a precision filter. The inlet of the quartz sand filter is connected to the outlet of the water pump, and its outlet is connected to the inlet of the activated carbon filter. The outlet of the activated carbon filter is connected to the inlet of the precision filter, and the outlet of the precision filter is connected to the inlet of the reverse osmosis unit. The concentrate outlet of the reverse osmosis unit is connected to the inlet of the concentrated brine tank, and the clear water outlet is connected to the inlet of the desalination tank. After this filtration, pure, impurity-free fresh water is obtained. Ideally, the pump between the filter unit and the raw saline water tank should be a booster pump to increase the pressure of the raw water. It is also best to install a high-pressure pump between the outlet of the filter unit and the inlet of the reverse osmosis unit to improve the reverse osmosis filtration capacity. The obtained fresh water enters the fresh water tank, and the concentrated brine tank is connected to the automatic evaporation device. The salt obtained by evaporating the concentrated brine through the automatic evaporation device enters the salt tank.

Claims

1. A system for treating and transforming saline-alkali land by returning it to the field, characterized in that: The device includes a saline-alkali water return-to-field device, which includes a water distribution network and multiple underground drip irrigation pipes. The underground drip irrigation pipes are installed below the surface layer of the saline-alkali land to be treated. The outlet end of the water distribution network is connected to the underground drip irrigation pipes, and the inlet end of the water distribution network is used to receive fresh water obtained after desalination of the saline-alkali water.

2. The saline-alkali land return-to-field treatment and transformation system as described in claim 1, characterized in that: The saline-alkali water returning device also includes a pressure stabilizing tank, which has a water storage tank body. The water inlet of the tank body is used to receive fresh water, and the water outlet is connected to the water inlet of the water distribution network.

3. The saline-alkali land return-to-field treatment and transformation system as described in claim 1, characterized in that: It also includes a saline desalination device, which desalinates saline water to obtain concentrated brine and fresh water. The saline desalination device includes a reverse osmosis device, which converts saline water into concentrated brine and fresh water. Its concentrated brine outlet is connected to a concentrated brine tank, and its fresh water outlet is connected to the inlet of a pressure stabilizing tank.

4. The saline-alkali land return-to-field treatment and transformation system as described in claim 3, characterized in that, The saline water desalination device also includes a filtration device to filter impurities in the saline water.

5. The saline-alkali land return-to-field treatment and transformation system as described in claim 4, characterized in that, The filtration device includes a quartz sand filter, an activated carbon filter, and a precision filter. The inlet of the quartz sand filter is connected to the outlet of the water pump, and its outlet is connected to the inlet of the activated carbon filter. The outlet of the activated carbon filter is connected to the inlet of the precision filter, and the outlet of the precision filter is connected to the inlet of the reverse osmosis device. The concentrated water outlet of the reverse osmosis device is connected to the inlet of the concentrated brine tank, and the clear water outlet of the reverse osmosis device is connected to the inlet of the fresh water tank. The inlet of the water pump is connected to the saline water to be treated.

6. The saline-alkali land return-to-field treatment and transformation system as described in claim 5, characterized in that, It also includes a saline water collection device, which collects and contains saline water from the saline-alkali land, and the water inlet of the water pump is located inside the saline water collection device.

7. The saline-alkali land return-to-field treatment and transformation system as described in claim 1, characterized in that, It also includes a saline water tank, which is located between the water pump and the saline water collection device.

8. The saline-alkali land return-to-field treatment and transformation system as described in claim 5, characterized in that, A booster pump is installed between the saline water tank and the filtration device, and a high-pressure pump is installed between the outlet of the filtration device and the reverse osmosis device.

9. The saline-alkali land return-to-field treatment and transformation system as described in claim 2, characterized in that, The pressure stabilizing tank has an air vent that connects it to the outside atmosphere.

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