Method for treating saline-alkali soil in arid region

Abstract

The invention provides an arid region saline-alkali soil treatment method which comprises the following steps: step 1, region division: dividing saline-alkali soil into a planting region and a saline-alkali water collection and treatment region; 2, a planting area is constructed, the planting area is composed of an original layer, a first water drainage and salt guide layer, an air permeation prevention layer, a second water drainage and salt guide layer and a planting layer from bottom to top, the air permeation prevention layer can prevent salt from ascending, and the water drainage and salt guide layer can drain saline-alkaline water in soil; and step 3, constructing a saline-alkaline water collection and treatment area, and performing filtration and electro-adsorption salt reduction on the collected saline-alkaline water to realize recycling of the saline-alkaline water. Layered improvement of the planting area is combined with an integrated structure of saline-alkali water collection, ion adsorption and storage, the salt content of soil is reduced, the nutrient content of the soil is increased, and all-round treatment and utilization of'blocking ', 'discharging', 'treating 'and'using' of the saline-alkali water are achieved.

Description

Technical Field

[0001] The present invention relates to the treatment of saline-alkali land in arid areas, and in particular to a method for treating saline-alkali land in arid areas. Background Art

[0002] Saline-alkali land refers to land with excessive soluble salts in the soil, and the salt concentration is high. This soil environment will inhibit or even harm plant growth. The reason for land salinization is that the soil and groundwater contain too much salt. Under the strong surface evaporation, the shallow underground water is transported to the surface through capillaries and evaporated. In the process of capillary water transport to the surface, the salt in the water is also brought to the surface. After the water is evaporated, the soil salt rises through capillary action and accumulates in the soil surface. The salt remains on the surface and in the shallow soil. In this way, the accumulated salt is too much, and there is not enough fresh water to dilute and drain it away, which forms soil salinization.

[0003] The main problems encountered in the process of saline-alkali land management in the arid northwest region are: the northwest region has little rainfall and high evaporation, and salt migration is dominated by "upward" movement; saline-alkali land has poor air permeability and low nutrient content; irrigation and salt washing methods such as flooding can easily cause secondary salinization, and the discharged saline-alkali water has a high salt content and poses a risk of secondary pollution; traditional saline-alkali land drainage ditches have not taken slope management measures, which are prone to siltation, collapse and other problems, and cannot be used for a long time; traditional underground pipes for salt drainage are large in size and often blocked during use, causing drainage difficulties. Summary of the invention

[0004] To solve the above problems, the present invention discloses a method for managing saline-alkali land in arid areas, which combines stratified improvement of planting areas with an integrated structure for collecting, processing and storing saline-alkali water, thereby achieving improvement of the planting environment of saline-alkali land and resource utilization of saline-alkali water.

[0005] A method for treating saline-alkali land in an arid area comprises excavating a plurality of drainage channels on the saline-alkali land, wherein the drainage channels divide the saline-alkali land into a plurality of planting areas and saline-alkali water collection and treatment areas. The planting area is a layered improved structure, and the saline-alkali water collection and treatment area is an integrated structure for collecting, treating and storing saline-alkali water. The planting area comprises a planting layer, a drainage salt-conducting layer, a permeability-blocking gas layer and an original layer, wherein the drainage salt-conducting layer is located at the upper part of the permeability-blocking gas layer and the inner part of the original layer respectively; the drainage salt-conducting layer, the permeability-blocking gas layer and the original layer are all inverted V-shaped with a high middle and low sides, wherein the hydraulic slope of the slopes on both sides is 1%-2%. The saline-alkali water collection and treatment area consists of a drainage channel, a filtration collection pool, an electrosorption pool, a water storage pool and an evaporation pool, wherein the drainage channel comprises a drainage channel slope, a drainage channel bottom surface and a water level sensor, and the hydraulic slope of the drainage channel bottom surface is 3%-5%. A filtration collection pool, an electrosorption pool, a water storage pool and an evaporation pool are arranged at the end with the lowest slope of the drainage channel bottom surface.

[0006] A specific implementation method of a method for treating saline-alkali land in an arid area comprises the following steps:

[0007] Step 1. Regional division: divide the saline-alkali land into a planting area and a saline-alkali water collection and treatment area, with the saline-alkali water collection and treatment area and the planting area spaced apart; the planting area is used to plant vegetation or crops, and the saline-alkali water collection and treatment area is used to collect, treat and reuse the saline-alkali water discharged from the saline-alkali land.

[0008] Step 2. Construct the planting area. The planting area is composed of the original layer, the second drainage salt-conducting layer, the anti-permeability gas layer, the first drainage salt-conducting layer, and the planting layer from bottom to top. The original layer is located at the bottom, which is the saline-alkali soil exposed after the upper soil is stripped. The original layer is trimmed into an inverted V shape with a high middle and low sides, and the hydraulic slope of the slopes on both sides is 1%-2%. The second drainage salt-conducting layer is located inside the original layer and is composed of capillary water-conducting belts. The horizontal and vertical capillary water-conducting belts are laid at intervals of 40-60cm inside the original layer; the capillary water-conducting belt has a thickness of 4mm, a width of 30cm, a length ≥ the original layer, and both ends are located in the alkali drainage channel; the laying angle of the capillary water-conducting belt is consistent with the hydraulic slope of the original layer. The anti-permeability gas layer is located on the upper part of the original layer, with a thickness of 6-8cm. It is composed of super-hydrophobic particles. The slope of the anti-permeability gas layer is consistent with the hydraulic slope of the original layer. 5% of plant gum is added to the super-hydrophobic particles for compaction, and the compaction degree is ≥60% to ensure the stability of the anti-permeability gas layer. The water drop contact angle of the super hydrophobic particles is 110°-160°, the particle size is (0.2-4mm):(0.5-8mm)=1:1, the porosity is ≤35%, and the bulk density is 1300Kg / m 3 -1800Kg / m 3. The first drainage salt-conducting layer is located above the impermeable gas layer. The first drainage salt-conducting layer is composed of capillary water-conducting belts. The laying spacing of the capillary water-conducting belts is 50-80cm; the thickness of the capillary water-conducting belt is 4mm, the width is 30cm, the length is ≥ the original layer, and both ends are located in the drainage channel; the laying angle of the capillary water-conducting belt is consistent with the hydraulic slope of the original layer. The planting layer is located above the first drainage salt-conducting layer. The thickness of the planting layer is 60-80cm. It is laid by the stripped original saline-alkali soil and then microbial fertilizer is applied. The hydraulic slope of the planting layer is 0%. The microbial fertilizer is made by mixing and fermenting microbial agents and organic waste in a ratio of 1:90. The microbial agents include one or more of Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium yeast, Trichoderma viride, Aspergillus niger, Penicillium oxalicum, and Bacillus polymyxa. It has the advantages of enhancing soil water retention capacity, improving plant disease resistance, and accelerating fermentation process. Organic waste is composed of agricultural and forestry waste and livestock manure in a ratio of 3:7. The fermentation time of microbial fertilizer is 15 days per cycle, during which the temperature is controlled at 40℃-45℃ and the humidity is controlled at 30%-40%. The fermented microbial fertilizer can reduce the salt content in the soil and increase the nutrient content in the soil.

[0009] Step 3. Construct a saline-alkali water collection and treatment area. The saline-alkali water collection and treatment area is spaced apart from the planting area. The saline-alkali water collection and treatment area consists of a drainage channel, a filtration collection pool, an electrosorption pool, a water storage pool, and an evaporation pool. The drainage channel is used to collect saline-alkali water in the planting area. The drainage channel consists of a drainage channel slope, a drainage channel bottom, and a water level sensor. The drainage channel slope is connected to the planting area. The drainage channel slope is composed of solid waste-based organic materials that have been fully digested with heavy metals. The solid waste-based organic materials are fly ash, coal gangue, animal feces, and agricultural and forestry wastes mixed in a ratio of 3:2:4:1, and then digested and fermented with heavy metals. 10% of plant gum is added during spraying to enhance the stability of the slope; the drainage channel slope is planted with vegetation, among which native salt-alkali-tolerant vegetation is planted above the impermeable air layer, and salt-alkali-tolerant aquatic vegetation is planted below the impermeable air layer. The water level sensor is located below the impermeable gas layer and is used to monitor the water level in the drainage channel. When the water level reaches the threshold, the pumps on both sides of the filter pool are started to drain the saline water in the drainage channel into the filter pool. The hydraulic slope of the bottom of the drainage channel is 3%-5%, which is convenient for the flow of saline water.

[0010] A filter collection pool, an electric adsorption pool, a water storage pool, and an evaporation pool are installed on the side with a low slope at the bottom of the drainage channel. The filter collection pool is divided into two parts: a filter pool and a collection pool. Pumps are installed on both sides of the filter pool. A filter layer is installed on the outside of the pump to block larger impurities in the saline-alkali water. The filter layer is detachable for easy cleaning. The filter is located in the filter pool and is connected to two pumps. After the saline-alkali water is filtered in the filter, it passes through the drain port of the filter and is stored in the collection pool.

[0011] The filtration collection tank is connected to the electrosorption tank, which includes a concentrated water inlet, a fresh water inlet, a pump A, a pump B, and an electrosorption unit. Pump A is connected to the collection tank through a PVC pipe, and is used to transport the saline water in the collection tank to the electrosorption tank for desalination. The fresh water inlet is connected to the water storage tank, and is used to transport the fresh water after electrosorption to the water storage tank for storage. Pump B is connected to the water storage tank through a PVC pipe, and is used to transport the fresh water in the water storage tank to the electrosorption tank for electrode desorption. The concentrated water inlet is connected to the evaporation tank, and is used to transport the concentrated water after electrode desorption to the evaporation tank. The PVC pipes used by pumps A and B are concealed pipes. Pumps A and B are equipped with flow regulators on their outsides. By controlling the water output of pumps A and B, the water flow rate through the electrode unit can be adjusted. Different water flow rates will affect the desalination efficiency of saline water. The water inlet flow rate of the electrosorption unit not only affects the amount of water processed by the electrosorption unit per unit time, but also affects the length of time that saline water stays in the flow channel of the electrode unit, thereby determining the water quality of the electrosorption effluent. The water inlet flow rate is controlled at 16-23 mL / s.

[0012] The electrosorption unit includes an electrode group and a power regulator. The electrode group is composed of at least one group of positive and negative electrodes. When water flows through the electrode absorption unit, the positive and negative electrodes respectively absorb ions with opposite charges in the water to reduce the concentration of mineral ions in the water. The power regulator is used to control the opening and closing of the concentrated water outlet and the fresh water outlet, the current direction of the electrode absorption unit and the voltage between the electrode group plates. The current direction can change the positive and negative charges of the electrode plates to achieve the exchange of positive and negative electrodes. The voltage between the electrode group plates will affect the desalination efficiency of saline-alkali water. The inter-plate voltage applied on both sides of the electrode group affects the electric field strength in the flow channel, which is the driving force for the directional movement of ions and directly affects the desalination efficiency of electrosorption. The inter-plate voltage is controlled at 1.7-1.9V. In the process of treating saline-alkali water with the electrosorption unit, increasing the processing time of the electrosorption unit can increase the contact time between the saline-alkali water and the electrode, give full play to the adsorption capacity of the electrode, thereby reducing the ion concentration in the water and improving the effluent water quality.

[0013] The process of treating saline-alkali water in the electrosorption cell is divided into electrode adsorption process, intermittent period, and electrode desorption process. The specific steps are as follows:

[0014] (1) Electrode adsorption process: The power regulator adjusts the power supply of the electrode unit to the positive power supply, the inter-plate voltage is controlled at 1.7-1.9V, and the flow regulator controls the water flow at 16-23mL / s. At this time, the concentrated water outlet is closed, the fresh water outlet is opened, the pump A is started, and the pump B is closed. The saline water in the collection pool enters the electrode unit through the pump A, and the fresh water produced after the electrode unit adsorbs enters the water storage tank through the fresh water outlet. The processing time is controlled at 17.5-18.5min.

[0015] (2) Interval period: The power regulator cuts off the power supply, the concentrate outlet is closed, the fresh water outlet is closed, and both pump A and pump B are turned off. The intermission period is controlled within 10 seconds.

[0016] (3) Electrode desorption process: The power regulator adjusts the power supply of the electrode unit to the reverse power supply, the inter-plate voltage is controlled at 1.7-1.9V, and the flow regulator controls the water flow at 16-23mL / s. At this time, the fresh water inlet is closed, the concentrated water inlet is opened, the pump A is closed, and the pump B is started. The fresh water in the water storage tank enters the electrode unit through the pump B, and the concentrated water produced after the electrode unit is desorbed enters the evaporation tank through the concentrated water inlet. The processing time is controlled at 2.5-3min.

[0017] The water storage tank is connected to the electric adsorption tank. A water pump C is installed inside the water storage tank. The water pump C is connected to the irrigation belt for irrigation of the planting area.

[0018] The evaporation pool is connected to the electric adsorption pool. The evaporation pool is used to evaporate the concentrated saline water produced after the electrode is desorbed. The evaporation pool consists of a condensation top, a titanium oxide evaporation plate, a water collection tank, and a water pipe. The condensation top is triangular and made of transparent quartz material. It has the functions of light transmission, condensation, and no dripping. The titanium oxide evaporation plate is located at the bottom of the evaporation pool. The titanium oxide nitride coating of the titanium oxide evaporation plate can absorb solar energy, generate heat energy, and accelerate the evaporation of water vapor. The water collection tank is located at the bottom of the condensation top and is used to collect water droplets condensed on the condensation top. The water pipe is used to connect the water collection tank and the water storage tank to transport the collected fresh water to the water storage tank for storage.

[0019] Beneficial effects of the present invention:

[0020] 1. The microbial fertilizer fermented from microbial agents and organic waste can increase the number of microorganisms in the soil and reduce the salt content in the soil. This method is simple and easy to carry out, has no restrictions on the fermentation environment, and can quickly achieve the treatment of saline-alkali land.

[0021] 2. The original layer is trimmed into an inverted V shape with a high middle and low sides, and a capillary water guide belt is laid. This can use gravity to play a natural drainage role and drain the moisture inside the soil. The project workload is small and there will be no blockage or other problems.

[0022] 3. Laying the impermeable air layer can cut off the "upward" channel of capillary water in the soil and reduce soil salt backflow. The drainage and salt-conducting layers are laid above and below the impermeable air layer, which can timely discharge the saline-alkali water above and below the impermeable air layer, realizing the combination of "blocking" and "drainage".

[0023] 4. The present invention combines the electro-adsorption desalination technology with filtration, storage and evaporation. By filtering and electro-adsorption desalination of the collected saline-alkali water, effective treatment of saline-alkali wastewater is achieved. By further evaporating the wastewater using solar energy, further treatment of the electro-adsorption desalination wastewater is achieved. The combination of the above technologies achieves efficient utilization of saline-alkali wastewater and saves energy consumption.

[0024] 5. The present invention uses solid waste-based organic materials to reinforce the slope of the alkali drainage channel, and plants suitable vegetation in layers on the slope, thereby achieving the stability and landscape effect of the alkali drainage channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : Structural diagram of the present invention;

[0026] Figure 2 : Structural diagram of the planting area of ​​the present invention;

[0027] Figure 3 : The structural diagram of the saline-alkali water collection and treatment area of ​​the present invention;

[0028] Figure 4 : Structural diagram of the filtering and collecting pool of the present invention;

[0029] Figure 5 : A front view of the electrosorption cell of the present invention;

[0030] Figure 6 : Rear view of the electrosorption cell of the present invention;

[0031] Figure 7 : A structural diagram of the electric suction unit of the present invention;

[0032] Figure 8 : The water storage tank and evaporation tank structure diagram of the present invention;

[0033] Fig. 9 : A cross-sectional view of the evaporation pond of the present invention;

[0034] Planting area 1, second drainage salt-conducting layer 101, original layer 102, air-blocking layer 103, first drainage salt-conducting layer 104, planting layer 105, capillary water-conducting belt 106, saline-alkali water collection and treatment area 2, drainage channel 201, filtration collection pool 202, electrosorption pool 203, water storage pool 204, evaporation pool 205, drainage channel slope 2011, drainage channel bottom 2012, water level sensor 2013, filtration pool 2021, collection pool 2022, pump 2023, filter 2024, filtration layer 2025, drainage outlet 2026, concentrated water outlet 2031, fresh water outlet 2032, pump A 2033, pump B 2034, electrosorption unit 2035, electrode group 2036, power supply controller 2037, pump C 2041, condensation top 2051, titanium oxide nitride evaporation plate 2052, water collecting tank 2053, water pipe 2054, limit sensor 2053, water injector 2054. DETAILED DESCRIPTION

[0035] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0036] Depend on Figure 1-2 It can be seen that the planting area 1 is composed of the original layer 102, the second drainage salt-conducting layer 101, the air-blocking layer 103, the first drainage salt-conducting layer 104, and the planting layer 105 from bottom to top. The original layer 102 is located at the bottom, which is the saline-alkali soil exposed after the upper soil is stripped. The original layer 102 is trimmed into an inverted V shape with a high middle and low sides, and the hydraulic slope of the slopes on both sides is 1%-2%. The second drainage salt-conducting layer 101 is located inside the original layer 102 and is composed of capillary water-conducting belts 106. The capillary water-conducting belts 106 are laid horizontally and vertically at intervals of 40-60 cm; the capillary water-conducting belts 106 are 4 mm thick, 30 cm wide, and ≥ the original layer in length, and both ends are located in the alkali drainage channel; the laying angle of the capillary water-conducting belt 106 is consistent with the hydraulic slope of the original layer 102. The anti-permeable gas layer 103 is located on the upper part of the original layer 102, has a thickness of 6-8 cm, and is composed of super-hydrophobic particles. The slope of the anti-permeable gas layer 103 is consistent with the hydraulic slope of the original layer 102. 5% of plant gum is added to the super-hydrophobic particles for compaction, and the compaction degree is ≥60% to ensure the stability of the anti-permeable gas layer. The water drop contact angle of the super-hydrophobic particles is 110°-160°, the particle size is (0.2-4mm): (0.5-8mm) = 1:1, the porosity is ≤35%, and the bulk density is 1300Kg / m 3 -1800Kg / m3 The first drainage salt-conducting layer 104 is located above the impermeable gas layer 103. The first drainage salt-conducting layer 104 is composed of a capillary water-conducting belt 106. The laying interval of the capillary water-conducting belt 106 is 50-80cm. The capillary water-conducting belt 106 has a thickness of 4mm, a width of 30cm, a length ≥ the original layer, and both ends are located in the alkali drainage channel. The laying angle of the capillary water-conducting belt 106 is consistent with the hydraulic gradient of the original layer 102. The planting layer 105 is located above the first drainage salt-conducting layer 104. The thickness of the planting layer 105 is 60-80cm. It is laid by stripping the original saline-alkali soil and applying microbial fertilizer. The hydraulic gradient of the planting layer 105 is 0%. Microbial fertilizer is made by mixing microbial agents and organic waste in a ratio of 1:90 and fermenting them. The microbial agents include one or more of Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium yeast, Trichoderma viride, Aspergillus niger, Penicillium oxalicum, and Bacillus polymyxa. It has the advantages of enhancing soil water retention, improving plant disease resistance, and accelerating the fermentation process. Organic waste is composed of agricultural and forestry waste and livestock manure mixed in a ratio of 3:7. The fermentation time of microbial fertilizer is 15 days per cycle, during which the temperature is controlled at 40℃-45℃ and the humidity is controlled at 30%-40%.

[0037] Table 1 Comparison of soil salt content before and after the transformation of the planting area

[0038]

[0039] Depend on Figure 1It can be seen that the saline-alkali water collection and treatment area 2 is spaced apart from the planting area 1, and the saline-alkali water collection and treatment area 2 is composed of a drainage channel 201, a filtration collection pool 202, an electric adsorption pool 203, a water storage pool 204, and an evaporation pool 205. The drainage channel 201 is used to collect saline-alkali water in the planting area, and the drainage channel 201 is composed of a drainage channel slope 2011, a drainage channel bottom 2012, and a water level sensor 2013. The slope 2011 of the alkali drainage channel is connected to the planting area 1. The slope 2011 of the alkali drainage channel is formed by spraying solid waste-based organic materials that have been fully digested with heavy metals. The solid waste-based organic materials are made by mixing fly ash, coal gangue, animal feces, and agricultural and forestry wastes in a ratio of 3:2:4:1, and then digested with heavy metals and fermented. 10% of plant gum is added during spraying to enhance the stability of the slope. The slope 2011 of the alkali drainage channel is planted with vegetation, wherein native salt-alkali tolerant vegetation is planted above the impermeable air layer 103, and salt-alkali tolerant aquatic vegetation is planted below the impermeable air layer 103. The water level sensor 2013 is located below the impermeable air layer 103 and is used to monitor the water level in the alkali drainage channel 201. When the water level reaches the threshold, the pump 2023 of the filter collection pool 202 is started to discharge the saline water in the alkali drainage channel 201 into the filter pool 2021. The bottom surface of the drainage channel is hardened with ecological cement in 2012, and the hydraulic slope of the bottom surface is 3%-5%, which is convenient for the flow of saline water.

[0040] Depend on Figure 3-4 It can be seen that a filter collection pool 202, an electric adsorption pool 203, a water storage pool 204, and an evaporation pool 205 are installed on the side with a low slope of the bottom surface 2012 of the alkali drainage channel. The filter collection pool 202 is divided into two parts: a filter pool 2021 and a collection pool 2022. Pumps 2023 are installed on both sides of the filter pool 2021. A filter layer 2025 is installed on the outside of the pump 2023 to block larger impurities in the saline water. The filter layer 2025 is detachable for easy cleaning. The filter 2024 is located in the filter pool 2021 and is connected to the two pumps 2023. After the saline water is filtered in the filter 2024, it passes through the drain port 2026 of the filter and is stored in the collection pool 2022.

[0041] Depend on Figure 3 , Figure 5-7It can be seen that the filtration collection tank 202 is connected to the electrosorption tank 203, and the electrosorption tank 203 includes a concentrated water port 2031, a fresh water port 2032, a pump A 2033, a pump B 2034, and an electrosorption unit 2035. The pump A 2033 is connected to the collection tank 2022 through a PVC pipe, and is used to transport the saline water in the collection tank 2022 to the electrosorption tank 203 for desalination. The fresh water port 2032 is connected to the water storage tank 204, and is used to transport the fresh water after the electrosorption to the water storage tank 204 for storage. The pump B 2034 is connected to the water storage tank 204 through a PVC pipe, and is used to transport the fresh water in the water storage tank 204 to the electrosorption tank 203 for electrode desorption. The concentrated water port 2031 is connected to the evaporation tank 205, and is used to transport the concentrated water after the electrode desorption to the evaporation tank 205.

[0042] The PVC pipes used by the pump A 2033 and the pump B 2034 are all concealed pipes. The outsides of the pumps A 2033 and B 2034 are equipped with flow regulators. By controlling the water output of the pumps A 2033 and B 2034, the water flow rate through the electrode adsorption unit 2035 can be adjusted. Different water flow rates will affect the desalination efficiency of saline water. The water inlet flow rate of the electrosorption unit 2035 not only affects the amount of treatment per unit time of the electrosorption unit, but also affects the length of time the saline water stays in the flow channel of the electrode unit, thereby determining the water quality of the electrosorption effluent. The water inlet flow rate is controlled at 16-23 mL / s.

[0043] The electrosorption unit 2035 includes an electrode group 2036 and a power regulator 2037. The electrode group 2036 is composed of at least one group of positive and negative electrodes. When water flows through the electrode absorption unit 2035, the positive and negative electrodes respectively absorb ions with opposite charges in the water to reduce the concentration of mineral ions in the water. The power regulator 2037 is used to control the opening and closing of the concentrated water port 2031 and the fresh water port 2032, the current direction of the electrode absorption unit 2035 and the inter-plate voltage of the electrode group 2036. The inter-plate voltage will affect the desalination efficiency of saline water. The inter-plate voltage applied on both sides of the electrode plate affects the electric field strength in the flow channel, which is the driving force for the directional movement of ions and directly affects the desalination efficiency of electrosorption. The inter-plate voltage is controlled at 1.7-1.9V. In the process of treating saline water by the electrosorption unit, increasing the treatment time of the electrosorption unit can increase the contact time between the saline water and the electrode, give full play to the adsorption capacity of the electrode, thereby reducing the ion concentration in the water and improving the effluent water quality.

[0044] The process of treating saline water in the electrosorption cell 203 is divided into an electrode adsorption process, an intermittent period, and an electrode desorption process. (1) Electrode adsorption process: The power regulator 2037 adjusts the power supply of the electrode group to a positive power supply, and the inter-plate voltage is controlled at 1.7-1.9V. The flow regulator controls the water flow at 16-23mL / s. At this time, the concentrated water port 2031 is closed, the fresh water port 2032 is opened, the pump A 2033 is started, and the pump B 2034 is closed. The saline water in the collection tank 2022 enters the electrosorption unit 2035 through the pump A 2033, and the fresh water produced after the electrode unit adsorbs enters the water storage tank 204 through the fresh water port 2032. The treatment time is controlled at 17.5-18.5min. (2) Interval period: the power regulator 2037 cuts off the power supply, the concentrated water inlet 2031 is closed, the fresh water inlet 2032 is closed, the pump A 2033 and the pump B 2034 are both closed, and the interval period is controlled within 10 seconds. (3) Electrode desorption process: the power regulator 2037 adjusts the power supply of the electrode group to a reverse power supply, the inter-plate voltage is controlled at 1.7-1.9V, and the flow regulator controls the water flow at 16-23mL / s. At this time, the fresh water inlet 2032 is closed, the concentrated water inlet 2031 is opened, the pump A 2033 is closed, and the pump B 2034 is started. The fresh water in the water storage tank 204 enters the electrosorption unit 2035 through the pump B 2034, and the concentrated water produced after electrode desorption enters the evaporation tank 205 through the concentrated water inlet 2032. The processing time is controlled at 2.5-3min.

[0045] Table 2 Comparison of electrosorption cell before and after treatment of saline-alkali water

[0046]

[0047]

[0048] Depend on Figure 3 It can be seen that the water storage tank 204 is connected to the electric adsorption tank 203, and a water pump C is installed inside the water storage tank 204. The water pump C 2041 is connected to the irrigation belt for irrigating the planting area 1.

[0049] Depend on Figure 8It can be seen that the evaporation pool 205 is connected to the electric adsorption pool 203, and the evaporation pool 205 is used to evaporate the concentrated saline water produced after the electrode is desorbed. The evaporation pool 205 consists of a condensation top 2051, a titanium oxide evaporation plate 2052, a water collection tank 2053, and a water pipe 2054. The condensation top 2051 is triangular and made of transparent quartz material, which has the functions of light transmission, condensation, and no dripping. The titanium oxide evaporation plate 2052 is located at the bottom of the evaporation pool 205. The titanium oxide evaporation plate 2052 has a titanium oxide coating that can absorb solar energy, generate heat energy, and accelerate the evaporation of water vapor. The water collection tank 2053 is located at the lower part of the condensation top 2051, and is used to collect water droplets condensed on the condensation top 2051. The water pipe 2054 is used to connect the water collection tank 2053 and the water storage tank 204, and transport the collected fresh water to the water storage tank 204 for storage.

[0050] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above technical features.

Claims

1. A method for treating saline-alkali land in arid areas, characterized by: The following steps are involved: Step 1: Regional division: the saline-alkali land is divided into a planting area and a saline-alkali water collection and treatment area, with the saline-alkali water collection and treatment area and the planting area spaced apart; the planting area is used to plant vegetation or crops, and the saline-alkali water collection and treatment area is used to collect, treat, and reuse the saline-alkali water discharged from the saline-alkali land; Step 2: construct a planting area, which consists of an original layer, a first drainage and salt-conducting layer, a permeability-blocking layer, a second drainage and salt-conducting layer, and a planting layer from bottom to top. The permeability-blocking layer can block the upward movement of salt, and the drainage and salt-conducting layer can discharge saline-alkali water in the soil; Step 3: Construct a saline-alkali water collection and treatment area, which includes a filtration collection pool, an electrosorption pool, a water storage pool, and an evaporation pool. The saline-alkali water can be reused by filtering the collected saline-alkali water and rainfall and reducing the salt by electrosorption.

2. The method for treating saline-alkali land in arid areas according to claim 1, characterized in that: The step 2 specifically comprises: the planting area (1) comprises, from bottom to top, an original layer (102), a second drainage salt-conducting layer (101), a permeable gas barrier layer (103), a first drainage salt-conducting layer (104) and a planting layer (105); the second drainage salt-conducting layer (101) is located inside the original layer (102) and is composed of a capillary water-conducting belt (106), and transverse and longitudinal capillary water-conducting belts (106) are laid inside the original layer (102) at intervals of 40-60 cm; the permeable gas barrier layer (103) is located on the upper part of the original layer (102), has a thickness of 6-8 cm, and is composed of super-hydrophobic particles. The slope of the impermeable gas layer (103) is consistent with the hydraulic slope of the original layer (102); the first drainage salt-conducting layer (104) is located above the impermeable gas layer (103), the first drainage salt-conducting layer (104) is composed of a capillary water-conducting belt (106), and the laying spacing of the capillary water-conducting belt (106) is 50-80 cm; the planting layer (105) is located above the first drainage salt-conducting layer (104), the thickness of the planting layer (105) is 60-80 cm, and microbial fertilizer is applied after the stripped original saline-alkali soil is laid, and the hydraulic slope of the planting layer (105) is 0%.

3. The method for treating saline-alkali land in arid areas according to claim 2, characterized in that: The original layer (102) is located at the bottom and is the saline-alkali soil exposed after the upper soil is stripped off. The original layer (102) is trimmed into an inverted V shape with a high middle and low sides, wherein the hydraulic slope of the slopes on both sides is 1%-2%; 5% of plant gum is added to the super-hydrophobic particles for compaction, and the compaction degree is ≥60%, wherein the water drop contact angle of the super-hydrophobic particles is 110°-160°, the particle size is (0.2-4mm):(0.5-8mm)=1:1, the porosity is ≤35%, and the bulk density is 1300Kg / m 3 -1800Kg / m 3 .

4. The method for treating saline-alkali land in arid areas according to claim 2, characterized in that: The capillary water conducting belt (106) on the first drainage salt conducting layer (104) has a thickness of 4 mm, a width of 30 cm, a length ≥ the original layer, and both ends are located in the alkali drainage channel (102); the laying angle of the capillary water conducting belt (106) is consistent with the hydraulic gradient of the original layer (102); the capillary water conducting belt (106) on the second drainage salt conducting layer (101) has a thickness of 4 mm, a width of 30 cm, a length ≥ the original layer, and both ends are located in the alkali drainage channel (201); the laying angle of the capillary water conducting belt (106) is consistent with the hydraulic gradient of the original layer (102).

5. The method for treating saline-alkali land in arid areas according to claim 1, characterized in that: The saline-alkali water collection and treatment area (2) is composed of an alkali drainage channel (201), a filtration collection pool (202), an electric adsorption pool (203), a water storage pool (204), and an evaporation pool (205); the alkali drainage channel (201) is composed of an alkali drainage channel slope (2011), an alkali drainage channel bottom surface (2012), and a water level sensor (2013); the alkali drainage channel slope (2011) is connected to the planting area (1), and the alkali drainage channel slope (2011) is formed by spraying solid waste-based organic materials that have been fully digested with heavy metals. Vegetation is planted, wherein native salt-alkali tolerant vegetation is planted above the impermeable air layer (103), and salt-alkali tolerant aquatic vegetation is planted below the impermeable air layer (103); a water level sensor (2013) is located below the impermeable air layer (103); pumps (223) on both sides of the filter pool (221) discharge saline-alkali water in the drainage channel (201) into the filter pool (2021); the bottom surface (2012) of the drainage channel is hardened with ecological cement, wherein the hydraulic slope of the bottom surface is 3%-5%, which is convenient for the flow of saline-alkali water.

6. A method for treating saline-alkali land in arid areas according to claim 5, characterized in that: A filtering and collecting pool (202), an electric adsorption pool (203), a water storage pool (204), and an evaporation pool (205) are installed on the side with a low slope of the bottom surface (2012) of the alkali drainage channel; the filtering and collecting pool (202) is divided into two parts, namely, a filtering pool (2021) and a collecting pool (2022); pumps (2023) are installed on both sides of the filtering pool (2021); and a filtering layer (2025) is installed on the outer side of the pumps (2023); the filter (2024) is located in the filtering pool (2021) and is connected to the two pumps (2023); after the saline-alkali water is filtered in the filter (224), it passes through the drain outlet (2026) of the filter and is stored in the collecting pool (2022).

7. The method for treating saline-alkali land in arid areas according to claim 5, characterized in that: The evaporation pool (205) is connected to the electric adsorption pool (203); the evaporation pool (205) is composed of a condensation top (2051), a titanium oxide evaporation plate (2052), a water collection tank (2053), and a water delivery pipe (2054); the titanium oxide evaporation plate (2052) is located at the bottom of the evaporation pool (205); the water collection tank (2053) is located at the lower part of the condensation top (2051); the water delivery pipe (2054) is used to connect the water collection tank (2053) and the water storage tank (204) to transport the collected fresh water to the water storage tank for storage; the condensation top (2051) is triangular and made of transparent quartz material.

8. The method for treating saline-alkali land in arid areas according to claim 6, characterized in that: The filtration collection pool (202) is connected to the electrosorption pool (203), and the electrosorption pool (203) comprises a concentrated water inlet (2031), a fresh water inlet (2032), a pump A (2033), a pump B (2034), and an electrosorption unit (2035); the pump A (2033) is connected to the collection pool (2022) via a PVC pipe, and is used to transport the saline water in the collection pool (2022) to the electrosorption pool (203) for desalination treatment; the fresh water inlet (2032) is connected to the water storage pool (204), and is used to transport the fresh water after the electrosorption to the water storage pool (204) is stored; a pump B (2034) is connected to the water storage tank (204) through a PVC pipe, and is used to transport the fresh water in the water storage tank (204) to the electric adsorption tank (203) for electrode desorption; a concentrated water outlet (2031) is connected to the evaporation tank (205), and is used to transport the concentrated water after electrode desorption to the evaporation tank (205); the water storage tank (204) is connected to the electric adsorption tank (203), and a pump C (2041) is installed inside the water storage tank (204), and the pump C (2041) is connected to an irrigation belt for irrigation of the planting area (1).

9. The method for treating saline-alkali land in arid areas according to claim 7, characterized in that: The outer sides of the water pump A (2033) and the water pump B (2034) are both provided with flow regulators, and the water inlet flow rate of the electric adsorption unit (2035) is 16-23 mL / s; the electric adsorption unit (2035) includes a power regulator (2037) and an electrode group (2036), and the electrode group (2036) is composed of at least one group of positive and negative electrodes. When water flows through the electrode adsorption unit (2035), the positive and negative electrodes respectively adsorb ions with opposite charges in the water, thereby reducing the mineral ion concentration of the water.

10. The method for treating saline-alkali land in arid areas according to claim 7, characterized in that: The process of treating saline-alkali water by the electrosorption cell (203) treated by the adsorption unit operation is divided into an electrode adsorption process, an intermittent period, and an electrode desorption process; the specific process is: Process (1) Electrode adsorption process: The power regulator adjusts the power supply of the electrode group to a positive power supply, the inter-plate voltage is controlled at 1.7-1.9V, and the flow regulator controls the water flow at 16-23mL / s. At this time, the concentrated water inlet (2031) is closed, the fresh water inlet (2032) is opened, the pump A (2033) is started, and the pump B (2034) is closed; the saline water in the collection tank (2022) enters the electrosorption unit (2035) through the pump A (2033), and the fresh water generated after the adsorption of the electrode unit enters the water storage tank (204) through the fresh water inlet (2032). The processing time is controlled at 17.5-18.5min; Process (2) intermittent period: the power regulator cuts off the power supply, the concentrated water inlet (2031) is closed, the fresh water inlet (2032) is closed, the pump A (2033) and the pump B (2034) are both closed, and the intermittent period is controlled within 10 seconds; Process (3) electrode desorption process: the power regulator adjusts the power supply of the electrode group to a reverse power supply, the inter-plate voltage is controlled at 1.7-1.9V, and the flow regulator controls the water flow at 16-23mL / s. At this time, the fresh water inlet (2032) is closed, the concentrated water inlet (2031) is opened, the pump A (2033) is closed, and the pump B (2034) is started; the fresh water in the water storage tank (204) enters the electrosorption unit (2035) through the pump B (2034), and the concentrated water generated after electrode desorption enters the evaporation tank (205) through the concentrated water inlet (2032), and the processing time is controlled at 2.5-3min.

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