Tunnel gushing wastewater resourceization irrigation method and system based on water and fertilizer integration

Abstract

The application discloses a tunnel gushing wastewater resourceization irrigation method and system based on water and fertilizer integration, relates to the field of ecological irrigation, and enters water and fertilizer requirement parameters of corresponding vegetation according to adaptive vegetation types, calculates fertilizer supplement amount in combination with fertilizer content data of purified gushing water, uniformly mixes water-soluble fertilizer and the purified gushing water by an intelligent fertilizer distribution system, and forms a water and fertilizer mixture; for different vegetation type regions, corresponding irrigation modes are deployed; an ecological restoration region adopts drip irrigation combined with infiltration irrigation, an agricultural region adopts drip irrigation under a film, an economic forest region adopts micro-sprinkling irrigation, and the water and fertilizer mixture is delivered according to a set irrigation frequency and dosage. The application achieves the irrigation water quality standard of the tunnel gushing wastewater through sand setting, coagulation sedimentation, targeted heavy metal removal and salt reduction treatment, replaces traditional underground water or surface water irrigation, relieves water resource pressure in drought and water shortage regions, and avoids environmental risks of direct discharge of gushing water.

Description

Technical Field

[0001] This invention relates to the field of ecological irrigation technology, and in particular to a method and system for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management. Background Technology

[0002] As highway construction extends into mountainous and ecologically sensitive areas, large amounts of water often flow into the tunnels during excavation. Direct discharge of such water not only wastes water resources but may also carry pollutants such as heavy metals and high salt ions, damaging the surrounding water environment and soil ecology. This problem is particularly acute in water-scarce and ecologically fragile areas such as arid valleys.

[0003] Existing tunnel runoff wastewater treatment technologies mostly focus on single purification methods, such as sedimentation and coagulation, without deeply integrating with irrigation needs, resulting in low utilization rates of the purified runoff. Meanwhile, traditional irrigation often suffers from water-fertilizer separation, with fertilizer application controlled based on experience, leading to significant nutrient waste. Furthermore, irrigation patterns are not designed according to vegetation type (ecological restoration vegetation, crops, economic forests) and terrain slope, easily causing soil erosion or uneven irrigation. In addition, existing technologies lack real-time monitoring and dynamic control of soil moisture and vegetation growth status, making it difficult to meet the dual requirements of ecological protection and resource utilization in environmentally sensitive areas, and failing to balance ecological restoration effects with agricultural production benefits.

[0004] Therefore, there is an urgent need for an integrated technology that can purify tunnel gushing wastewater, coordinate water and fertilizer use, adapt to different zones, and dynamically regulate the water supply, in order to solve the problems of water waste, significant ecological impact, and low irrigation efficiency of existing technologies. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method and system for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management. The technical solution adopted is as follows: The method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management includes the following steps: Step 1: After passing through grit removal and coagulation sedimentation, the water enters the targeted purification unit, where heavy metal ions are removed by a modified zeolite adsorption column, and then the salinity is reduced by a biochar filter layer to obtain purified effluent. Step 2: Real-time monitoring of pH, conductivity, heavy metal content, total nitrogen and total phosphorus in the purified effluent using multi-parameter sensors; and determination of suitable vegetation type for irrigation based on a preset adaptation matrix. Step 3: Based on the suitable vegetation type, enter the water and fertilizer requirements of the corresponding vegetation, and calculate the amount of fertilizer to be supplemented by combining the fertilizer content data of the purified water. The intelligent fertilizer mixing system will evenly mix the water-soluble fertilizer with the purified water to form a water-fertilizer mixture. Step 4: Deploy corresponding irrigation modes for different vegetation types: drip irrigation combined with seepage irrigation is used in ecological restoration areas, drip irrigation under film is used in agricultural areas, and micro-sprinkler irrigation is used in economic forest areas, delivering water and fertilizer mixture according to the set irrigation frequency and dosage.

[0006] Optionally, in step 1, after the modified zeolite adsorption column is saturated, it is regenerated by passing a 2%-3% hydrochloric acid solution through it, with a regeneration cycle of 15-20 days; the biochar filter layer is replaced every set period, and the replaced biochar is used as organic fertilizer for soil improvement in the ecological restoration area.

[0007] Optionally, in step 2, the judgment logic of the preset adaptation matrix is ​​as follows: when all indicators of the purified water meet the requirements of a certain water quality classification, the vegetation type corresponding to that water quality classification is matched; when a single indicator is at the critical value of an adjacent water quality classification, the higher priority vegetation type is matched according to the principle of choosing the higher; when any indicator exceeds the threshold of the three water quality classifications, the water is returned to the targeted purification unit for reprocessing.

[0008] Optionally, in step 3, the formula for calculating the amount of single-nutrient fertilizer supplementation is: Where Q is the mass of pure nutrient required per unit area per month for the corresponding single nutrient during the target growth period of the vegetation; G is the fertilizer requirement of the vegetation; C is the concentration of the corresponding single nutrient in the purified gushing water monitored in real time in step 2, which is directly collected by a multi-parameter sensor; I is the planned irrigation amount; η is the absorption and utilization efficiency of the corresponding single nutrient in the soil. Unit conversion factor.

[0009] Optionally, the intelligent fertilizer blending system in step 3 includes multiple independent fertilizer storage tanks, a variable frequency metering pump, and a double-helix mixing tank. The control logic of the intelligent fertilizer blending system includes: receiving water quality data from step 2 and irrigation data from step 4, automatically calling the calculation formula for the amount of single nutrient fertilizer to calculate the Q value; adjusting the fertilizer delivery flow rate of the variable frequency metering pump according to the Q value; and installing a concentration sensor in the double-helix mixing tank to monitor the concentration of the water-fertilizer mixture in real time. When the concentration deviation is greater than the set threshold, the metering pump flow rate or the mixing speed is automatically adjusted.

[0010] Optionally, in step 4, the irrigation pattern deployment is combined with terrain slope optimization: in areas with a slope of less than or equal to 10°, the drip irrigation tape is laid along the contour lines; in areas with a slope of 10° to 20°, the micro-sprinklers are arranged in a denser pattern at the top and sparser pattern at the bottom, with a spacing of 1-1.5 meters on the uphill slope and 1.8-2 meters on the downhill slope; in areas with a slope greater than 20°, the seepage irrigation pipes are laid in a Z-shape, with a bend every 10 meters, in conjunction with slope intercepting ditches, with a spacing of 5 meters between the ditches.

[0011] Optionally, the seasonal adjustment rules for irrigation frequency and single irrigation amount in step 4 are as follows: The dry season is from March to May: irrigation frequency in the ecological restoration area is once every 7 days, with a single irrigation volume of 5±0.5 cubic meters per mu; irrigation frequency in the agricultural area is once every 5 days, with a single irrigation volume of 8±0.5 cubic meters per mu; irrigation frequency in the economic forest area is once every 3 days, with a single irrigation volume of 12±1 cubic meters per mu. The rainy season is from June to September: Rainfall is collected using a tipping bucket rain gauge. When the daily rainfall R is less than or equal to 10 mm, the irrigation frequency is increased by 50%; when the daily rainfall R is greater than 10 mm but less than or equal to 20 mm, the irrigation frequency is increased by 100% and the amount of water irrigated per irrigation is reduced by 30%; when the daily rainfall R is greater than 20 mm, irrigation is suspended for that day. The transitional season from October to February is as follows: In the ecological restoration area, irrigation is carried out once every 10 days, with a single irrigation volume of 4±0.5 cubic meters per mu; in the economic forest area, irrigation is carried out once every 15 days, with a single irrigation volume of 10±1 cubic meters per mu.

[0012] Optionally, soil moisture, vegetation growth status, and irrigation water quality can be monitored through a sensor network, and the data can be uploaded to a cloud platform to dynamically adjust irrigation volume, water-fertilizer ratio, and irrigation frequency, forming a closed-loop control.

[0013] Optional, dynamic adjustment rules include: increasing the amount of irrigation per irrigation session by 12%-15% when soil moisture content is below the lower limit of the suitable range for the corresponding vegetation; reducing the amount of fertilizer supplemented with the corresponding nutrients by 8%-10% when the content of available nutrients in the soil is above the upper limit of the suitable range for the corresponding vegetation; and increasing the amount of fertilizer supplemented with the corresponding nutrients by 4%-8% when vegetation growth indicators are below the lower limit of the target range for the corresponding vegetation. Vegetation growth indicators include chlorophyll SPAD value, canopy leaf area index (LAI), and harvest organ development indicators. When the water quality indicators at the outlet of the irrigation branch pipe exceed the water quality classification threshold corresponding to the current irrigation area, the system switches to irrigating the vegetation area that is compatible with the water quality indicators, and at the same time, the excess water is returned to the biochar filter layer of the targeted purification unit. When the compatibility score is less than 60 points, the emergency pause mechanism is triggered, the sensor data and equipment status are manually checked, and irrigation is restarted after troubleshooting.

[0014] A water and fertilizer integrated irrigation system for the resource utilization of tunnel runoff wastewater is designed to realize a water and fertilizer integrated irrigation method for tunnel runoff wastewater. The system includes a pretreatment module, a water quality monitoring module, an intelligent fertilizer application module, a zoned irrigation module, and a closed-loop control module. The pretreatment module is used to treat tunnel wastewater by sedimentation, coagulation, targeted removal of heavy metals, and desalination to obtain purified water that meets the standards and for storage. The water quality monitoring module is used to collect data on purified water quality, soil moisture and nutrients, vegetation growth status, irrigation water quality and rainfall, and transmit them to the closed-loop control module. The intelligent fertilizer mixing module is used to calculate the amount of fertilizer to be added and to quantitatively deliver fertilizer and purified water to form a water-fertilizer mixture with uniform concentration. The zoned irrigation module is used to precisely deliver the water-fertilizer mixture to different vegetation zones in zones. The closed-loop control module is used to receive monitoring data, calculate the suitability score, issue control commands, and trigger emergency alarms.

[0015] In summary, the present invention has at least one of the following beneficial technical effects: This invention provides a method and system for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management. Through sedimentation, coagulation, targeted removal of heavy metals, and desalination, the tunnel runoff wastewater meets irrigation water quality standards, replacing traditional groundwater or surface water irrigation, alleviating water resource pressure in arid and water-scarce areas, and avoiding the environmental risks of direct discharge of runoff water. The amount of fertilizer to be supplemented is calculated based on the nutrient requirements of vegetation and the nutrient content of the inflow water. Combined with an intelligent fertilizer mixing system, water and fertilizer are mixed evenly, reducing fertilizer waste and lowering the water and fertilizer costs of agriculture and ecological irrigation. Differentiated irrigation models are designed based on the vegetation characteristics and topographic slope of ecological restoration areas, agricultural areas, and economic forest areas, taking into account both irrigation efficiency and soil and water conservation, so as to improve the ecological restoration effect and the yield of crops and economic forests. By constructing a closed-loop control system through sensor networks and a cloud platform, the irrigation volume, water-fertilizer ratio, and irrigation frequency can be adjusted in real time to avoid insufficient or excessive irrigation and ensure that the system is stable and adaptable to ecological and production needs in the long term. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process of the tunnel gushing wastewater resource irrigation method based on integrated water and fertilizer management according to the present invention.

[0017] Figure 2 This is a schematic diagram of the architecture of a tunnel wastewater resource-based irrigation system based on integrated water and fertilizer management, according to a specific embodiment of the present invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings.

[0019] This invention discloses a method and system for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management.

[0020] Reference Figure 1 and Figure 2 Example 1, a method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management, includes the following steps: Step 1: After passing through grit removal and coagulation sedimentation, the water enters the targeted purification unit, where heavy metal ions are removed by a modified zeolite adsorption column, and then the salinity is reduced by a biochar filter layer to obtain purified effluent. Step 2: Real-time monitoring of pH, conductivity, heavy metal content, total nitrogen and total phosphorus in the purified effluent using multi-parameter sensors; and determination of suitable vegetation type for irrigation based on a preset adaptation matrix. Step 3: Based on the suitable vegetation type, enter the water and fertilizer requirements of the corresponding vegetation, and calculate the amount of fertilizer to be supplemented by combining the fertilizer content data of the purified water. The intelligent fertilizer mixing system will evenly mix the water-soluble fertilizer with the purified water to form a water-fertilizer mixture. Step 4: Deploy corresponding irrigation modes for different vegetation types: drip irrigation combined with seepage irrigation is used in ecological restoration areas, drip irrigation under film is used in agricultural areas, and micro-sprinkler irrigation is used in economic forest areas, delivering water and fertilizer mixture according to the set irrigation frequency and dosage.

[0021] In Example 2, after the modified zeolite adsorption column is saturated, it is regenerated by passing a 2%-3% hydrochloric acid solution through it, with a regeneration cycle of 15-20 days. The biochar filter layer is replaced every set period, and the replaced biochar is used as organic fertilizer for soil improvement in the ecological restoration area.

[0022] By adopting the above technical solution, the density difference between suspended solids (such as silt particles) and water in the tunnel wastewater is utilized. Through gravity settling, the larger suspended solids naturally settle in the sedimentation tank, achieving preliminary clarification of the wastewater and preventing suspended solids from clogging the adsorption materials or affecting the coagulation effect in subsequent processes.

[0023] Adding a coagulant to the gushing water causes it to hydrolyze and form positively charged hydroxyl polymers. These polymers neutralize the negatively charged fine colloidal particles in the gushing water, disrupting their stability. Subsequently, the colloidal particles collide and aggregate to form visible flocs. These flocs settle in the coagulation sedimentation tank under gravity, further reducing the turbidity and colloidal impurity content of the gushing water.

[0024] Zeolite itself possesses a porous structure and ion exchange properties. After modification with hydrochloric acid, the number of surface active adsorption sites increases, allowing it to specifically bind heavy metal ions (such as Pb) in flowing water through physical adsorption and ion exchange. 2+ Cd 2+ Cr 6+ ), to separate and remove heavy metals from the gushing water; Biochar (such as corn stalk-based biochar) has an ultra-large specific surface area and abundant surface functional groups (such as hydroxyl and carboxyl groups). It can capture salt ions in the water through physical and chemical adsorption, while adjusting the pH value of the water to a suitable range for vegetation, and finally obtain purified water that meets irrigation requirements.

[0025] pH monitoring is based on the glass electrode method. When the electrode comes into contact with the flowing water, a pH-related potential difference is generated, and the pH value is obtained through signal conversion. Conductivity monitoring is based on the principle of ionic conductivity. The higher the concentration of salt ions in the water, the greater the conductivity. The salt content is reflected by measuring the conductivity of the solution. Heavy metal content monitoring is based on ion-selective electrode method or atomic absorption spectrometry. A specific electrode responds only to the target heavy metal ions, and the generated current signal is positively correlated with the heavy metal concentration. Total nitrogen and total phosphorus monitoring is based on ultraviolet spectrophotometry. Under alkaline conditions, total nitrogen is oxidized to nitrate and total phosphorus is oxidized to phosphate. Both produce absorbance at specific wavelengths. The absorbance and concentration follow the Lambert-Beer law, thereby calculating the content.

[0026] A matrix was constructed based on the differences in physiological tolerance thresholds and growth requirements of different vegetation types—agricultural areas and economic forests have higher requirements for water quality (such as low heavy metals and low salt), while vegetation in ecological restoration areas has a slightly wider tolerance range; by comparing the actual indicators of the purified water flow with the water quality classification thresholds in the matrix, suitable vegetation types were determined to avoid physiological damage to vegetation caused by water quality exceeding standards (such as heavy metal toxicity and salt stress).

[0027] The total amount of nutrients required for vegetation growth consists of two parts: the nutrients contained in the flowing water and the additional fertilizer. By deducting the nutrients already provided by the flowing water and combining the absorption and utilization rate of fertilizer in the soil, the amount of fertilizer that needs to be supplemented is determined, ensuring that the nutrient supply is precisely matched to the needs of the vegetation, so as not to waste fertilizer or affect growth due to insufficient nutrients.

[0028] The intelligent fertilizer mixing system achieves mechanical mixing through a double-helix stirring structure. The double-helix blades can drive water and fertilizer to move in different directions, increasing the contact area between water and fertilizer. At the same time, the system uses a variable frequency metering pump to precisely control the fertilizer delivery flow rate, and combines a concentration sensor to monitor the concentration of the mixed solution in real time. This ensures that the water-soluble fertilizer and the purified water are fully mixed to form a water-fertilizer mixture with a uniform concentration, avoiding localized areas where the fertilizer content is too high and burns the vegetation, or too low and fails to meet the needs.

[0029] The ecological restoration area adopts drip irrigation + seepage irrigation: drip irrigation delivers water and fertilizer to the surface root system of vegetation through drippers to meet the absorption needs of shallow roots; seepage irrigation pipes are buried in the deep soil layer to deliver water and fertilizer to the deep root system, which is suitable for the three-dimensional root distribution of trees and shrubs, while reducing surface evaporation and soil erosion. In agricultural areas, drip irrigation under plastic film is used: the plastic film can block the water evaporation channel, reduce evaporation loss, and inhibit weed growth; the drip irrigation tape is laid close to the ground, which directly delivers water and fertilizer to the crop root zone, avoiding nutrient loss with surface runoff; Micro-sprinkler irrigation is used in economic forest areas: micro-sprinklers produce fine water mist that can evenly cover the canopy and root system of fruit trees. This is suitable for the well-developed structure of the canopy of economic forests, satisfying the transpiration needs of branches and leaves while also moistening the soil around the roots.

[0030] After the modified zeolite reaches saturation in adsorbing heavy metal ions, its surface adsorption sites are occupied by heavy metal ions, and it loses its adsorption capacity; when a 2%-3% hydrochloric acid solution is introduced, the hydrogen ions (H+) in the hydrochloric acid... + It can react with heavy metal ions (such as Pb) adsorbed by zeolite. 2 + Cd 2+ An ion exchange reaction occurs, displacing heavy metal ions from the zeolite adsorption sites and discharging them with the hydrochloric acid solution. After the ion exchange is complete, adsorption sites are released again on the zeolite surface, restoring its adsorption performance, and it can be used again for heavy metal removal. Setting a regeneration cycle of 15-20 days is based on the premise that the heavy metal concentration in the tunnel wastewater is stable, and is a reasonable time interval for the zeolite's adsorption capacity to recover from saturation. This avoids excessively frequent regeneration, which would increase costs, and also prevents heavy metal leakage due to adsorption saturation.

[0031] During the use of biochar filter layers, their porous structure and surface functional groups are gradually occupied by salt ions in the flowing water, weakening the salt reduction effect and requiring regular replacement. Although the replaced biochar loses its salt reduction ability, it still contains abundant carbon elements, a small amount of nitrogen, phosphorus, potassium nutrients and trace elements, and its porous structure can improve soil permeability and water retention capacity.

[0032] In Example 3, in step 2, the judgment logic of the preset adaptation matrix is ​​as follows: when all indicators of the purified water meet the requirements of a certain water quality classification, the vegetation type corresponding to that water quality classification is matched; when a single indicator is at the critical value of an adjacent water quality classification, the higher priority vegetation type is matched according to the principle of choosing the higher; when any indicator exceeds the threshold of the three water quality classifications, the water is returned to the targeted purification unit for reprocessing.

[0033] By adopting the above technical solutions, the tolerance of different vegetation types (ecological restoration vegetation, crops, and economic forests) to water quality is multi-dimensional and synergistic. Meeting a single indicator standard cannot guarantee normal vegetation growth. For example, if the pH of the purified water meets the standard but the heavy metal content exceeds the standard, although the pH is suitable for the vegetation's growth needs, heavy metal ions will be absorbed into the vegetation through the roots, leading to root necrosis, leaf yellowing, and other toxic reactions after accumulation. If the electrical conductivity meets the standard but the total nitrogen content is too low, it cannot meet the nutrient requirements of crops or economic forests, easily leading to reduced yields. In the preset adaptation matrix, each indicator (pH, electrical conductivity, heavy metals, total nitrogen, and total phosphorus) of each water quality classification corresponds to the "safe tolerance upper limit / suitable range" of a certain type of vegetation. Only when all indicators simultaneously meet the classification requirements can it be ensured that the water quality will not negatively affect the vegetation from any dimension such as pH stress, salt stress, heavy metal toxicity, or nutrient deficiency, achieving comprehensive "water quality-vegetation" adaptation and ensuring irrigation safety and vegetation growth efficiency.

[0034] Example 4, in step 3, the formula for calculating the amount of single-nutrient fertilizer supplementation is: Where Q is the mass of pure nutrient required per unit area per month for the corresponding single nutrient during the target growth period of the vegetation; G is the fertilizer requirement of the vegetation; C is the concentration of the corresponding single nutrient in the purified gushing water monitored in real time in step 2, which is directly collected by a multi-parameter sensor; I is the planned irrigation amount; η is the absorption and utilization efficiency of the corresponding single nutrient in the soil. Unit conversion factor.

[0035] Example 5: In step 3, the intelligent fertilizer blending system includes multiple independent fertilizer storage tanks, a variable frequency metering pump, and a double-helix mixing tank. The control logic of the intelligent fertilizer blending system includes: receiving water quality data from step 2 and irrigation data from step 4, automatically calling the calculation formula for the amount of single nutrient fertilizer to calculate the Q value; adjusting the fertilizer delivery flow rate of the variable frequency metering pump according to the Q value; and installing a concentration sensor in the double-helix mixing tank to monitor the concentration of the water-fertilizer mixture in real time. When the concentration deviation is greater than the set threshold, the metering pump flow rate or the mixing speed is automatically adjusted.

[0036] By adopting the above technical solution, the nutrient requirements of the vegetation during its target growth period must be met by a combination of nutrients from the wastewater flowing through the tunnel and additional fertilizer. Relying solely on the nutrients from the wastewater may lead to nutrient deficiencies in the vegetation (such as yellowing leaves and stunted growth); conversely, blindly supplementing fertilizer without deducting the nutrients from the wastewater will result in nutrient excess. The formula subtracts the nutrients supplied by the wastewater from the total nutrient requirement of the vegetation to first obtain the theoretical nutrient gap, then adjusts it based on fertilizer absorption efficiency to finally determine the actual amount of fertilizer needed, achieving precise matching of supply and demand.

[0037] G (Vegetation Nutrient Requirements): This is the pure mass of a single nutrient (such as nitrogen, phosphorus, or potassium) required per unit area per month to maintain normal growth, development, and yield formation during the target growth period, such as the tuber enlargement stage of crops or the fruiting stage of economic forests. This value is based on the physiological characteristics of vegetation, such as the nitrogen requirement for photosynthesis, the potassium requirement for fruit development, the determination of basic soil fertility, and production / ecological goals, and serves as the benchmark for calculating fertilizer supplementation.

[0038] (Nutrient supply from runoff): This refers to the mass of a single nutrient that tunnel runoff wastewater can provide to vegetation, which needs to be quantified using "concentration × volume × unit conversion". C (Nutrient Concentration in Inflow Water): Reflects the natural content of the nutrient in the inflow water. It is collected in real time by multi-parameter sensors (such as total nitrogen concentration and total phosphorus concentration) and is the basis for calculating the concentration of nutrients supplied by the inflow water. I (Planned Irrigation Volume): This is the volume of water delivered to vegetation per unit area per month, which is consistent with the water requirement of the vegetation (natural rainfall needs to be deducted). It is the basis for calculating the volume of water supplied with nutrients. 10 -3(Unit conversion factor): Since the unit of C is milligrams per liter and the unit of I is cubic meters per acre per month, the product of the two is milligrams per acre per month, which needs to be converted to a unit of 10⁻. 3 Convert to kilograms per mu per month to ensure consistency with the unit of G (kilograms per mu per month) and avoid unit confusion that could lead to calculation errors.

[0039] η (fertilizer absorption efficiency): This is the proportion of supplemented fertilizer that is actually absorbed and utilized by the plant roots. Fertilizer in the soil can be lost due to various factors, and not all supplemented fertilizer can be utilized by plants.

[0040] Example 6, Step 4: The irrigation pattern deployment is combined with terrain slope optimization: In areas with a slope of less than or equal to 10°, the drip irrigation tape is laid along the contour lines; in areas with a slope of 10° to 20°, the micro-sprinklers are arranged in a denser pattern at the top and sparser pattern at the bottom, with a spacing of 1-1.5 meters on the uphill slope and 1.8-2 meters on the downhill slope; in areas with a slope greater than 20°, the drip irrigation pipes are laid in a Z-shape, with a bend every 10 meters, in conjunction with slope intercepting ditches, with a spacing of 5 meters between the ditches.

[0041] Example 7, the seasonal adjustment rules for irrigation frequency and single irrigation amount in step 4 are as follows: The dry season is from March to May: irrigation frequency in the ecological restoration area is once every 7 days, with a single irrigation volume of 5±0.5 cubic meters per mu; irrigation frequency in the agricultural area is once every 5 days, with a single irrigation volume of 8±0.5 cubic meters per mu; irrigation frequency in the economic forest area is once every 3 days, with a single irrigation volume of 12±1 cubic meters per mu. The rainy season is from June to September: Rainfall is collected using a tipping bucket rain gauge. When the daily rainfall R is less than or equal to 10 mm, the irrigation frequency is increased by 50%; when the daily rainfall R is greater than 10 mm but less than or equal to 20 mm, the irrigation frequency is increased by 100% and the amount of water irrigated per irrigation is reduced by 30%; when the daily rainfall R is greater than 20 mm, irrigation is suspended for that day. The transitional season from October to February is as follows: In the ecological restoration area, irrigation is carried out once every 10 days, with a single irrigation volume of 4±0.5 cubic meters per mu; in the economic forest area, irrigation is carried out once every 15 days, with a single irrigation volume of 10±1 cubic meters per mu.

[0042] By adopting the above technical solutions, in areas with a slope of less than or equal to 10°, the terrain is gentle but there is a slight possibility of water and fertilizer accumulation along the slope. The drip irrigation tape is laid along the contour lines so that the water outlets are at the same elevation, and the water and fertilizer are evenly infiltrated, avoiding uneven water and fertilizer distribution between high and low terrain.

[0043] In areas with a slope of 10°-20°: the water flow is faster on gentle slopes, and water and fertilizer are easily lost on the uphill slopes and easily become excessive on the downhill slopes. The micro-sprinklers are arranged in a "dense on the top and sparse on the bottom" manner. By increasing the density on the uphill slopes to make up for the loss and increasing the spacing on the downhill slopes to avoid excessive water, uniform coverage is achieved across the entire slope.

[0044] In areas with a slope greater than 20°: steep slopes have fast water flow and high runoff risk. The Z-shaped laying of the drip irrigation pipe slows down the flow rate by turning, extending the water and fertilizer retention time for root absorption; combined with the slope interception ditch, a small amount of runoff is intercepted to prevent erosion and loss and to recover water and fertilizer.

[0045] Dry season (March-May): Low rainfall, high evaporation, and vigorous water demand for vegetation. Based on differences in vegetation drought tolerance, the following schedule is set for the ecological restoration area: 7 days / time (5±0.5m). 3 / mu), agricultural areas 5 days / time (8±0.5m) 3 / mu), 3 days / time in economic forest areas (12±1m) 3 / acre), to meet growth requirements.

[0046] Rainy season (June-September): sufficient rainfall and weak evaporation. Adjust according to rainfall: when R≤10mm, increase frequency by 50%; when 10<R≤20mm, increase frequency by 100% and reduce dosage by 30%; when R>20mm, suspend use to prevent flooding and nutrient loss.

[0047] Transitional season (October-February): Low temperatures, slow vegetation growth, and low water requirements; ecological restoration area: every 10 days (4±0.5m). 3 / mu), economic forest areas 15 days / time (10±1m) 3 / acre), to maintain basic needs and avoid affecting dormancy.

[0048] Example 8: Soil moisture, vegetation growth status and irrigation water quality are monitored through a sensor network. The data is uploaded to a cloud platform to dynamically adjust irrigation amount, water-fertilizer ratio and irrigation frequency, forming a closed-loop control.

[0049] Example 9, the dynamic adjustment rules include: when the soil moisture content is lower than the lower limit of the suitable range for the corresponding vegetation, increase the amount of irrigation per irrigation by 12%-15%; when the content of available nutrients in the soil is higher than the upper limit of the suitable range for the corresponding vegetation, reduce the amount of fertilizer supplemented for the corresponding nutrients by 8%-10%; when the vegetation growth index is lower than the lower limit of the target range for the corresponding vegetation, increase the amount of fertilizer supplemented for the corresponding nutrients by 4%-8%. Vegetation growth indicators include chlorophyll SPAD value, canopy leaf area index (LAI), and harvest organ development indicators. When the water quality indicators at the outlet of the irrigation branch pipe exceed the water quality classification threshold corresponding to the current irrigation area, the system switches to irrigating the vegetation area that is compatible with the water quality indicators, and at the same time, the excess water is returned to the biochar filter layer of the targeted purification unit. When the compatibility score is less than 60 points, the emergency pause mechanism is triggered, the sensor data and equipment status are manually checked, and irrigation is restarted after troubleshooting.

[0050] By adopting the above technical solution, the sensor network is the core of data acquisition, monitoring soil moisture, vegetation growth status, and irrigation water quality to ensure the acquisition of key parameters throughout the irrigation chain. After the data is uploaded to the cloud platform, the platform uses a built-in water quality-soil-vegetation correlation model to comprehensively analyze the matching degree between the current irrigation plan and actual needs. Finally, based on the analysis results, the irrigation amount, water-fertilizer ratio, and irrigation frequency are dynamically adjusted to form a closed loop of monitoring feedback, plan adjustment, and effect verification. This ensures that irrigation always adapts to vegetation growth and environmental changes, avoiding insufficient or excessive irrigation caused by static plans.

[0051] Soil moisture content adjustment: When the soil moisture content is lower than the lower limit of the suitable range for vegetation, it means that the water absorbed by the roots cannot meet the transpiration and physiological needs of the vegetation, which can easily lead to wilting of leaves and stunted growth. Increasing the amount of irrigation per irrigation by 12%-15% can quickly replenish the soil moisture to the suitable range and balance the water supply and demand. Adjusting available nutrients in the soil: When available nutrients in the soil exceed the upper limit of the suitable range, nutrients will accumulate in the soil (e.g., excessive nitrogen can easily cause excessive growth, and excessive phosphorus will fix trace elements in the soil). Reducing the amount of fertilizer supplemented by 8%-10% can avoid the ecological risks (such as soil salinization) and resource waste caused by nutrient excess. Adjustment of vegetation growth indicators: Low chlorophyll SPAD value reflects nitrogen deficiency, low canopy leaf area index (LAI) reflects phosphorus and potassium deficiency, and low harvest organ development index reflects insufficient supply of key nutrients. Targeted increase of 4%-8% of the corresponding nutrient fertilizer supplementation can directly make up for the nutrient gap in vegetation growth and promote the recovery of physiological functions. Irrigation water quality adjustment: If the water quality at the outlet of the irrigation branch pipe exceeds the current regional classification threshold, it indicates that the water quality is no longer suitable for the vegetation in the area (e.g., high salinity will stress the growth of economic forests). Switching to a suitable area can avoid damage to the vegetation. The excess water can be returned to the biochar filter layer for secondary desalination / impurity removal, which can make it meet the standards again and realize the recycling of water resources. Adaptability score adjustment: If the adaptability score is less than 60, it indicates that the current irrigation plan is seriously unbalanced with the needs of vegetation and soil. Triggering an emergency pause can prevent irreversible damage caused by continuous improper irrigation. After manual verification of the fault, the system will be restarted to ensure stable operation.

[0052] Example 10: A tunnel runoff wastewater resource utilization irrigation system based on integrated water and fertilizer management, used to realize a method for resource utilization irrigation of tunnel runoff wastewater based on integrated water and fertilizer management. The system includes a pretreatment module, a water quality monitoring module, an intelligent fertilizer application module, a zoned irrigation module, and a closed-loop control module. The pretreatment module is used to treat tunnel wastewater by sedimentation, coagulation, targeted removal of heavy metals, and desalination to obtain purified water that meets the standards and for storage. The water quality monitoring module is used to collect data on purified water quality, soil moisture and nutrients, vegetation growth status, irrigation water quality and rainfall, and transmit them to the closed-loop control module. The intelligent fertilizer mixing module is used to calculate the amount of fertilizer to be added and to quantitatively deliver fertilizer and purified water to form a water-fertilizer mixture with uniform concentration. The zoned irrigation module is used to precisely deliver the water-fertilizer mixture to different vegetation zones in zones. The closed-loop control module is used to receive monitoring data, calculate the suitability score, issue control commands, and trigger emergency alarms.

[0053] The following specific embodiments illustrate the implementation principle of the present invention: This embodiment uses the Damai Tunnel on the Xuanwei-Huize Expressway in Yunnan Province as an example. The normal water inflow of the tunnel is 2427.6 m³. 3 / d, maximum inflow 3155.9m³ 3 / d, the tunnel site is located in the dry-hot valley area of ​​the Jinsha River, involving three types of vegetation areas: ecological restoration area, agricultural area, and economic forest area. The specific implementation is as follows: Vegetation zoning: Ecological restoration area: Located on the slope to the left of the tunnel exit, covering an area of ​​3 mu, planted with 1-year-old saplings of Dalbergia odorifera and local shrubs (Shrimp Flower), with a terrain slope of 15°-25°; Agricultural area: Located on a flat plot of land to the right of the tunnel entrance, covering an area of ​​2 mu, planted with potatoes (variety "Hezuo 88"), with a terrain slope of ≤10°; Economic forest area: Located on the gentle slope on the right side of the middle of the tunnel, covering an area of ​​2 mu, planted with soft-seed pomegranates (3-year-old trees, entering the fruiting period), with a terrain slope of 10°-15°.

[0054] Initial values ​​for key parameters: Initial water quality of tunnel runoff wastewater: turbidity 18 NTU, Pb 0.08 mg / L, Cd 0.02 mg / L, conductivity 4.5 mS / cm, pH 8.2, total nitrogen 0.6 mg / L, total phosphorus 0.12 mg / L; Seasonal climate data: In the dry season (April), the average daily evaporation is 6.2 mm and the average daily rainfall is 2.1 mm; in the rainy season (July), the average daily evaporation is 3.5 mm and the average daily rainfall is 18.3 mm; in the transitional season (November), the average daily evaporation is 1.8 mm and the average daily rainfall is 1.5 mm.

[0055] Step 1: Water purification treatment: Sedimentation: Wastewater from the tunnel is piped into a sedimentation tank (50m³ volume). 3 (Retention time 1.5h) Removes silt particles with a diameter ≥0.1mm, reducing effluent turbidity to 10 NTU; Coagulation and sedimentation: After sand settling, the gushing water enters the coagulation and sedimentation tank (volume 100m³).3 ), add 30 mg / L polyaluminum chloride through a flocculant dosing device, stir at 180 r / min, settle for 5 h, and the turbidity of the effluent drops to 5 NTU; Targeted purification: After coagulation, the gushing water is sequentially passed through two sets of parallel modified zeolite adsorption columns (1.2m in diameter, 2.8m in height, zeolite particle size 5-8mm, modified with 2.5% hydrochloric acid), with an empty bed residence time of 45min to remove Pb and Cd, and then flows through a 30cm thick corn straw-based biochar filter layer (particle size 2-5mm) to reduce salt ions; Purified effluent parameters: turbidity 3 NTU, Pb 0.02 mg / L, Cd 0.006 mg / L, conductivity 2.2 mS / cm, pH 7.2, total nitrogen 0.3 mg / L, total phosphorus 0.04 mg / L, stored at 4000 m³. 3 Purified water storage tank.

[0056] Adsorbent material recycling: Modified zeolite regeneration: After 15 days of operation, the heavy metal Pb at the adsorption column outlet rose to 0.03 mg / L. 2.5% hydrochloric acid solution (flow rate 1 m / h) was introduced for regeneration for 8 hours. After regeneration, the adsorption efficiency was restored to 92% and it can continue to be used. Biochar replacement: After 30 days of use, the salt reduction effect of biochar decreases (the electrical conductivity removal rate drops from 30% to 15%). Replace with new biochar. Crush the old biochar and spread it evenly in the ecological restoration area at a rate of 50 kg per acre to improve soil permeability.

[0057] Water quality-vegetation suitability assessment: The preset adaptation matrix is ​​shown in Table 1: Table 1 Adaptation determination After purification, the effluent had a pH of 7.2, conductivity of 2.2 mS / cm, Pb of 0.02 mg / L, Cd of 0.006 mg / L, total nitrogen of 0.3 mg / L, and total phosphorus of 0.04 mg / L. All indicators met the requirements for Class II water quality, and the water was deemed suitable for the ecological restoration area. A portion of the purified water was subjected to secondary biochar filtration (conductivity reduced to 1.4 mS / cm, Pb 0.008 mg / L), meeting the Class I water quality requirements, and was deemed suitable for agricultural and economic forest areas.

[0058] Fertilizer calculation and intelligent fertilizer blending: Calculation of single-nutrient fertilizer supplementation: Known parameters: G (potato nitrogen requirement) 8.65 kg / mu / month, C (total nitrogen concentration in flowing water) 0.3 mg / L, I (planned irrigation volume) 21 m³ / min. 3 / mu·month (water requirement 28m) 3 / mu·month, monthly rainfall 10m 3 / mu, effective rainfall = 10 × 0.7 = 7m 3 / mu, I=28-7=21), η (nitrogen fertilizer utilization rate) 0.4; Substituting into the formula: Q = [8.65 - (0.3 × 21 × 10]] -3 [8.65 - 0.0063] / 0.4 ≈ 21.61 kg / mu / month; Urea contains 46% nitrogen. The required amount of urea to be supplemented is approximately 46.98 kg / mu / month (21.61 / 0.46). In a 2-mu agricultural area, a single application of urea requires 93.96 kg of urea.

[0059] Intelligent fertilizer blending system operation: The system includes 3 independent fertilizer storage tanks (2m³ / s). 3 It stores urea, potassium dihydrogen phosphate, and potassium sulfate separately; a variable frequency metering pump (flow accuracy ±2%); and a 10m³ / h metering pump. 3 Double helix mixing tank; Receive water quality data (total nitrogen 0.3 mg / L) and irrigation data (21 m³ / L). 3 / mu·month), automatically calculate the Q value, and adjust the flow rate of the variable frequency metering pump according to the demand of 46.98kg / mu·month (47kg urea / 21m). 3 Water flow rate set at 4.7L / h). The concentration sensor inside the mixing tank monitors the concentration of the water-fertilizer mixture. The target concentration is 1.0%. When the actual concentration is 1.1% (deviation 10% > 5%), the system automatically reduces the flow rate of the metering pump by 10% and maintains the stirring speed at 300 r / min. After 10 minutes, the concentration stabilizes at 1.0%.

[0060] Zonal irrigation and seasonal adjustment: Irrigation pattern deployment (optimized by slope): Ecological restoration area (15°-25°): The drip irrigation pipes are laid in a Z-shape with a turn every 10m and a burial depth of 20cm, in conjunction with slope intercepting ditches spaced 5m apart; the drip irrigation heads are spaced 50cm apart and arranged along the drip irrigation pipe path; Agricultural areas (≤10°): Drip irrigation tape under the film is laid along the contour lines at 80cm intervals and covered with mulch film close to the ground; Economic forest area (10°-15°): Micro-sprinklers are arranged in a "dense on top and sparse on the bottom" pattern, with a spacing of 1.2m on the uphill slope and 1.8m on the downhill slope, an installation height of 1.2m, and a range of 1.5m.

[0061] Seasonal irrigation adjustments: Dry season (April): Irrigation in the ecological restoration area every 7 days, with a single irrigation volume of 5m³. 3 / mu; in agricultural areas, irrigation every 5 days, with a single irrigation volume of 8m³. 3 / mu; in economic forest areas, irrigation every 3 days / time, with a single irrigation volume of 12m³. 3 / mu; Rainy season (July): Daily rainfall 15mm, irrigation frequency in agricultural areas increased by 100% (from 5 days / time to 10 days / time), and irrigation volume per irrigation decreased by 30% (from 8mm). 3 / mu changed to 5.6m 3 / mu); Transitional season (November): Irrigation in the ecological restoration area every 10 days, with a single irrigation volume of 4m³. 3 / mu; in economic forest areas, irrigation every 15 days / time, with a single irrigation volume of 10m³. 3 / mu.

[0062] Closed-loop control and dynamic adjustment: Sensor network deployment: In the ecological restoration area: one soil moisture sensor (monitoring water content at 0-10cm and 10-20cm depth, accuracy ±1%) and one soil nutrient sensor (monitoring available N / P / K, accuracy ±5%) are installed for every 5 mu (approximately 0.33 hectares); one vegetation growth sensor (measuring plant height and SPAD value) is installed for every 10 Dalbergia odorifera trees. Irrigation branch pipe outlets: Water quality sensors (monitoring pH and conductivity, once per hour) are installed in each branch pipe area; tipping bucket rain gauges (accuracy 0.1mm) are installed in open areas.

[0063] Dynamically adjust execution: Soil moisture content adjustment: Soil moisture sensors in the ecological restoration area showed a moisture content of 14% in the 0-20cm depth (suitable range for *Pterocarpus macrocarpus* is 15%-25%). The cloud platform issued a command to increase the single irrigation amount by 12%, from 5m... 3 / mu adjusted to 5.6m 3 / mu; Vegetation growth adjustment: The SPAD value of soft-seeded pomegranate in the economic forest area is 38 (target range 40-50). The platform judges that the nitrogen is insufficient, so the nitrogen fertilizer supplementation is increased by 6%, and the urea supplementation is adjusted from 46.98 kg / mu·month to 49.8 kg / mu·month. Water quality adjustment: The conductivity of the branch pipe outlet in the agricultural area is 2.6 mS / cm (the threshold for Class I water quality is ≤1.5 mS / cm). The system automatically switches to irrigation in the ecological restoration area. Excess water flows back to the biochar filter layer for secondary treatment. After treatment, the conductivity is reduced to 2.1 mS / cm. Emergency pause: When the compatibility score is 58 points (<60 points), the emergency alarm device triggers an audible and visual alarm. Manual verification reveals a deviation in the soil sensor data. The system is restarted after calibration.

[0064] System module operation: Pretreatment module: Grit chamber, coagulation sedimentation tank, targeted purification unit, and water storage tank operate in tandem, treating an average of 2400 m³ of incoming water per day. 3 Produces 2350m³ of purified water 3 ; Water quality monitoring module: Each sensor collects an average of 288 data points per day, which are transmitted to the cloud via a LoRa module; Intelligent fertilizer blending module: blends fertilizer 3 times a day, processing 10m³ each time. 3 water; Zoned irrigation module: Daily irrigation volume 120m³ 3 The uniformity of water and fertilizer delivery in ecological restoration areas, agricultural areas, and economic forest areas reached 92%, 95%, and 93%, respectively. Closed-loop control module: The cloud platform calculates the adaptability score 24 times per day, issues 3-5 control commands, and triggers 0 emergency alarms (the system is stable after calibration).

[0065] Implementation results: Water resource utilization: The reuse rate of tunnel runoff wastewater has increased from 0% to 98%, saving an average of 120 cubic meters of groundwater per day. 3 This will alleviate the water shortage problem in the hot and dry valleys. Vegetation growth: In the ecological restoration area, the monthly height of the Dalbergia odorifera increased from 3cm to 5cm; in the agricultural area, the potato yield per mu reached 2500kg (a 15% increase compared to traditional irrigation); and in the economic forest area, the single fruit weight of soft-seed pomegranates increased by 10%. Ecological protection: The heavy metal content in the soil did not exceed the standard after irrigation, the water quality of the Niulanjiang Fish Protection Area was not affected, and the amount of soil erosion was reduced by 40% compared with traditional irrigation.

[0066] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management, characterized in that, Includes the following steps: Step 1: After passing through sand settling and coagulation sedimentation, the water enters the targeted purification unit. Heavy metal ions are removed by a modified zeolite adsorption column, and the salinity is reduced by a biochar filter layer to obtain purified water. After the modified zeolite adsorption column is saturated, it is regenerated by passing through a 2%-3% hydrochloric acid solution, with a regeneration cycle of 15-20 days. The biochar filter layer is replaced every set period, and the replaced biochar is used as organic fertilizer for soil improvement in the ecological restoration area. Step 2: The pH, conductivity, heavy metal content, total nitrogen and total phosphorus of the purified effluent are monitored in real time using multi-parameter sensors. Based on a preset adaptation matrix, the appropriate vegetation type for irrigation is determined. The determination logic of the preset adaptation matrix is ​​as follows: when all indicators of the purified effluent simultaneously meet the requirements of a certain water quality classification, the vegetation type corresponding to that water quality classification is matched; when a single indicator is at the critical value of an adjacent water quality classification, the higher priority vegetation type is matched according to the principle of choosing the higher priority; when any indicator exceeds the threshold of the three water quality classifications, the effluent is returned to the targeted purification unit for reprocessing. Step 3: Based on the suitable vegetation type, input the corresponding water and fertilizer requirements of the vegetation, and calculate the fertilizer supplementation amount by combining the fertilizer content data of the purified water. The intelligent fertilizer mixing system will then evenly mix the water-soluble fertilizer with the purified water to form a water-fertilizer mixture. The formula for calculating the supplementation amount of a single nutrient fertilizer is: Where Q is the mass of pure nutrient required per unit area per month for the corresponding single nutrient during the target growth period of the vegetation; G is the fertilizer requirement of the vegetation; C is the concentration of the corresponding single nutrient in the purified gushing water monitored in real time in step 2, which is directly collected by a multi-parameter sensor; I is the planned irrigation amount; η is the absorption and utilization efficiency of the corresponding single nutrient in the soil. Unit conversion factor; Step 4: Deploy corresponding irrigation modes for different vegetation types: drip irrigation combined with seepage irrigation is used in ecological restoration areas, drip irrigation under film is used in agricultural areas, and micro-sprinkler irrigation is used in economic forest areas, delivering water and fertilizer mixture according to the set irrigation frequency and dosage.

2. The method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management according to claim 1, characterized in that, Step 3's intelligent fertilizer blending system includes multiple independent fertilizer storage tanks, a variable frequency metering pump, and a double-helix mixing tank. The intelligent fertilizer blending system control logic includes: receiving water quality data from Step 2 and irrigation data from Step 4, automatically calling the calculation formula for the amount of single nutrient fertilizer to calculate the Q value; the variable frequency metering pump adjusts the fertilizer delivery flow rate according to the Q value; a concentration sensor is installed in the double-helix mixing tank to monitor the concentration of the water-fertilizer mixture in real time, and automatically adjusts the metering pump flow rate or mixing speed when the concentration deviation exceeds the set threshold.

3. The method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management according to claim 2, characterized in that, In step 4, the irrigation pattern deployment is combined with terrain slope optimization: in areas with a slope of less than or equal to 10°, the drip irrigation tape is laid along the contour lines; in areas with a slope of 10° to 20°, the micro-sprinklers are arranged in a denser pattern at the top and sparser pattern at the bottom, with a spacing of 1-1.5 meters on the uphill slope and 1.8-2 meters on the downhill slope; in areas with a slope greater than 20°, the seepage irrigation pipes are laid in a Z-shape, with a bend every 10 meters, in conjunction with slope intercepting ditches, with a spacing of 5 meters between the ditches.

4. The method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management according to claim 3, characterized in that, The seasonal adjustment rules for irrigation frequency and single irrigation amount in step 4 are as follows: The dry season is from March to May: irrigation frequency in the ecological restoration area is once every 7 days, with a single irrigation volume of 5±0.5 cubic meters per mu; irrigation frequency in the agricultural area is once every 5 days, with a single irrigation volume of 8±0.5 cubic meters per mu; irrigation frequency in the economic forest area is once every 3 days, with a single irrigation volume of 12±1 cubic meters per mu. The rainy season is from June to September: Rainfall is collected using a tipping bucket rain gauge. When the daily rainfall R is less than or equal to 10 mm, the irrigation frequency is increased by 50%; when the daily rainfall R is greater than 10 mm but less than or equal to 20 mm, the irrigation frequency is increased by 100% and the amount of water irrigated per irrigation is reduced by 30%; when the daily rainfall R is greater than 20 mm, irrigation is suspended for that day. The transitional season from October to February is as follows: In the ecological restoration area, irrigation is carried out once every 10 days, with a single irrigation volume of 4±0.5 cubic meters per mu; in the economic forest area, irrigation is carried out once every 15 days, with a single irrigation volume of 10±1 cubic meters per mu.

5. The method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management according to claim 4, characterized in that, By monitoring soil moisture, vegetation growth, and irrigation water quality through a sensor network, the data is uploaded to a cloud platform to dynamically adjust irrigation volume, water-fertilizer ratio, and irrigation frequency, forming a closed-loop control system.

6. The method for resource-based irrigation of tunnel runoff wastewater based on integrated water and fertilizer management according to claim 5, characterized in that, The dynamic adjustment rules include: when the soil moisture content is below the lower limit of the suitable range for the corresponding vegetation, increase the amount of irrigation per irrigation by 12%-15%; when the content of available nutrients in the soil is above the upper limit of the suitable range for the corresponding vegetation, reduce the amount of fertilizer supplemented with the corresponding nutrients by 8%-10%; when the vegetation growth index is below the lower limit of the target range for the corresponding vegetation, increase the amount of fertilizer supplemented with the corresponding nutrients by 4%-8%. Vegetation growth indicators include chlorophyll SPAD value, canopy leaf area index (LAI), and harvest organ development indicators. When the water quality indicators at the outlet of the irrigation branch pipe exceed the water quality classification threshold corresponding to the current irrigation area, the system switches to irrigating the vegetation area that is compatible with the water quality indicators, and at the same time, the excess water is returned to the biochar filter layer of the targeted purification unit. When the compatibility score is less than 60 points, the emergency pause mechanism is triggered, the sensor data and equipment status are manually checked, and irrigation is restarted after troubleshooting.

7. A tunnel wastewater resource-based irrigation system based on integrated water and fertilizer management, characterized in that: The system for implementing the tunnel runoff wastewater resource-based irrigation method based on integrated water and fertilizer management as described in claim 6 includes a pretreatment module, a water quality monitoring module, an intelligent fertilizer application module, a zoned irrigation module, and a closed-loop control module. The pretreatment module is used to treat tunnel wastewater by sedimentation, coagulation, targeted removal of heavy metals, and desalination to obtain purified water that meets the standards and for storage. The water quality monitoring module is used to collect data on purified water quality, soil moisture and nutrients, vegetation growth status, irrigation water quality and rainfall, and transmit them to the closed-loop control module. The intelligent fertilizer mixing module is used to calculate the amount of fertilizer to be added and to quantitatively deliver fertilizer and purified water to form a water-fertilizer mixture with uniform concentration. The zoned irrigation module is used to precisely deliver the water-fertilizer mixture to different vegetation zones in zones. The closed-loop control module is used to receive monitoring data, calculate the suitability score, issue control commands, and trigger emergency alarms.

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