CN115479750A - A groundwater recharge chemical plugging simulation experimental device and its experimental method - Google Patents

Abstract

The invention discloses a simulation experiment device and an experiment method for chemical blocking effect of groundwater recharge, wherein the experiment device comprises a water injection system, a radial recharge system, an overflow system and data monitoring; the radial recharging system comprises a fan-shaped sand box and a pumping and injection well; the fan-shaped sand box is filled with a water-containing medium, three sampling wells are further arranged in the water-containing medium, a water absorption hose is arranged in each sampling well, and the water absorption hoses are used for extracting a water sample in the water-containing layer to determine the water chemistry characteristics of the water sample. The invention has the beneficial effects that: the experiment method can simulate the radial recharge process of underground water, study the blocking effect of the recharge water chemical components on the recharge well, simulate the time-space change of the solution concentration in the chemical recharge blocking process of the underground water by changing the chemical properties of the experiment solution, reveal the chemical recharge blocking mechanism of the underground water and provide scientific basis for improving the recharge efficiency of the underground water. The experimental device is complete in structure, reasonable in spatial layout, strong in operability and controllable in influence factors.

Description

A groundwater recharge chemical plugging simulation experimental device and its experimental method

technical field

The invention relates to the technical field of groundwater dynamics and chemical clogging research, in particular to a groundwater recharge chemical clogging simulation experimental device and an experimental method thereof.

Background technique

At present, although there have been significant breakthroughs in the theory and application of groundwater recharge, the clogging effect still restricts the improvement of recharge efficiency. Differences in the chemical composition of groundwater can produce varying degrees of clogging. Iron and manganese have similar chemical properties, are widely distributed in groundwater, and are often affected by redox environment and acid-base environment. When the water quality conditions in the study area are poor, and the content of iron and manganese ions in the groundwater is high, when the groundwater recharge is carried out, the iron and manganese ions will chemically react with the medium in the aquifer and generate substances, which will cause the blockage of the recharge well. Therefore, it is of great significance to study the effect of different concentrations of recharge water quality on the clogging effect to improve the efficiency of groundwater recharge.

Contents of the invention

In view of this, the present invention provides a groundwater recharge chemical blockage simulation experiment device, including a water injection system, a radial recharge system, an overflow system and data monitoring;

The radial recharge system includes a fan-shaped sand box and a pumping and injecting well; the bottom of the pumping and injecting well is provided with a plurality of permeable holes, and the pumping and injecting well is vertically arranged at the axis of the fan-shaped sand box; The fan-shaped sand box is filled with an aqueous medium forming an aquifer, and the pumping and injection wells are connected to the aquifer through permeable holes; the fan-shaped sand box is also provided with three sampling wells, and each sampling well is provided with a vertical The set water intake pipe is used to draw water samples in the aquifer to determine the water chemical characteristics of the water samples;

The radial recharge system includes a pumping tank, a solute tank, a recharge pipe and a water pumping pipe, the solute tank is filled with an experimental solution, and both the pumping pipe and the refilling pipe extend into the pumping and injection well, The irrigation pipe and the water suction pipe are respectively connected with the solute tank and the water suction tank, and the recharge pipe and the water suction pipe are respectively provided with a water injection pump and a water suction pump;

The overflow device includes an overflow pool and an outlet pipe, the overflow pool is connected to the bottom of the fan-shaped sand box through the outlet pipe, and an overflow port is provided at the bottom of the overflow pool;

The data monitoring system includes a pressure measuring plate on which a plurality of pressure measuring tubes are arranged; the side wall of the fan-shaped sand box is provided with a plurality of pressure measuring holes arranged in an array, and one row of pressure measuring holes passes through multiple pressure measuring holes. A piezometric tube is respectively connected with a plurality of piezometric tubes, and the piezometric tube is used for water level change in the aquifer;

Further, the overflow pool is provided on a lifting device, and the lifting device is used to adjust the level of the overflow pool.

Further, three sampling wells are arranged along the radial line of the fan-shaped sand box, and the spacing between adjacent sampling wells is equal, and the spacing between adjacent sampling wells is 60cm.

Further, the pumping and injection well also includes a well wall, a water filter pipe, a sedimentation pipe and a filter material. It is filled with filter material constituting the water filter layer, a plurality of the permeable holes are distributed at the bottom of the well wall at equal intervals up and down, and a water stop layer is provided on the top of the water filter layer.

Further, the fan-shaped sand box includes two side plates and arc-shaped end plates, both side plates are connected to the pumping and injection well, and the angle between them is 20-60°, and the arc-shaped end plates are connected to the The end of the side panel.

Further, the two side panels are both acrylic panels.

Further, an arc-shaped baffle is also provided in the fan-shaped sand box, and the baffle separates a steady flow groove in the fan-shaped sand box, and a plurality of permeation holes are distributed on the baffle, and the steady flow The tank is filled with a steady flow medium.

Further, valves and flowmeters are provided on the return pipe and the suction pipe.

The present invention also provides a groundwater recharge chemical plugging simulation experiment method, the method uses the above-mentioned experimental device for simulating the radial recharge of groundwater, and the method includes the following steps:

S1: Observe and check whether the function of the experimental device is normal, perform exhaust operation on the pressure measuring plate, and connect the entire experimental device;

S2: Fill the fan-shaped sand box with an aqueous medium and compact it, and bury a suction hose in the aqueous medium;

S3: Prepare a specific concentration of iron-manganese ion solution, manganese ion solution or a mixed solution of the two to study the impact of different concentrations of experimental recharge water on groundwater recharge blockage,

S4: The water level of the overflow device is adjusted so that the liquid level of the overflow pool is higher than the liquid level of the aquifer. The distilled water source is connected externally through the overflow device, and the distilled water is first injected into the steady flow tank, and gradually penetrates into the water after the water flow is stable. In the quartz sand in the layer, saturate the water-containing medium and exhaust it, measure the permeability coefficient of the sand sample at this time, and perform the recharge test after the value tends to be stable;

S5: After the water saturation operation is completed, open the valve 2 and the water injection pump on the recharge pipe, and inject the experimental solution prepared in the solute tank into the recharge well through the water injection pump. During the experiment, use a flow meter to monitor the recharge volume and The flow rate of the overflow outlet is read and recorded on the pressure measuring tubes on the pressure measuring plate. At the same time, water samples in the aquifer are taken at regular intervals for water quality analysis to detect the concentration of iron and manganese ions and water quality parameters.

S6: Simulated recharge test: turn off the water injection pump and valve 2, turn on the water pump and valve 1, pump the solution in the sand box into the water pumping tank, during the pumping process, connect the external water source through the overflow device, and evenly inject distilled water into the steady flow tank , enter the aquifer through the permeable hole, monitor the concentration of the water sample in the sand box, and end a recharge test when the concentration is consistent with the concentration of the solution in the saturated stage;

S7: Change the composition of the experimental solution separately, and repeat the above steps S1-S6 several times under the condition of controlling variables, and compare the experimental results of each time.

Further, in the above step S7, the above steps S1-S6 were repeated three times, and the concentrations of the four groups of comparative test solutions prepared in the four recharge tests were: Fe ²⁺ : 0 mg/L, Mn ²⁺ : ³ mg/L; Fe 2+ ⁺ : 4 mg/L, Mn ²⁺ : 2 mg/L; Fe ²⁺ : 8 mg/L, Mn ²⁺ : 1 mg/L; Fe ²⁺ : 12 mg/L, Mn ²⁺ : 0 mg/L.

The beneficial effect of a groundwater recharge chemical blockage simulation experiment device and its experimental method of the present invention is: the experimental method can simulate the radial recharge process of groundwater, and the chemical composition of recharge water can be studied by studying the different iron and manganese ion contents in the recharge water samples By changing the chemical properties of the experimental solution, the time-space change of the solution concentration in the process of groundwater recharge chemical clogging is simulated; and the migration and changes of the chemical components of the experimental solution are used to reveal the chemical clogging of groundwater recharge. The mechanism provides a scientific basis for improving the efficiency of groundwater recharge. Moreover, the device has complete structure, reasonable space layout, strong operability and controllable influencing factors.

Description of drawings

Fig. 1 is a structural schematic diagram of a physical model of radial groundwater recharge according to the present invention.

FIG. 2 is a schematic diagram of the internal structure of the pumping and injecting well 4 .

In the above figure:

1-Fan-shaped sand box, 2-Steady flow tank, 3-Experiment platform, 4-Pumping water injection well, 5-Pumping water tank, 6-Solute tank, 7-Pressure measuring plate, 8-Overflow device, 9-Overflow pool, 10-overflow port, 11-outlet pipe, 12-lifting device, 13-suction pipe, 14-refill pipe, 15-flow meter, 16-suction pump, 17-water injection pump, 18-valve one, 19-valve Two, 20-suction hose, 21-water stop layer, 22-filter layer, 23-filter pipe, 24-sedimentation pipe.

detailed description

In order to make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

Please refer to Fig. 1 to Fig. 2, a groundwater recharge chemical clogging simulation experiment device, including a test bench 3, a water injection system, a radial recharge system, an overflow system and data monitoring.

The bottom of the test bench 3 is provided with a plurality of universal wheels.

The radial recharge system includes a fan-shaped sand box 1 and a water injection well 4; the water injection well 4 includes a well wall, a water filter pipe 23, a sedimentation pipe 24 and a filter material, and the water filter pipe 23 is located in the well wall , the lower end of the filter pipe 23 is provided with a settling pipe 24, and the outer wall of the filter pipe 23 and the inner wall of the well wall are filled with the filter material that constitutes the water filter layer 22; The spacing is distributed at the bottom of the well wall, and the top of the filter layer 22 is provided with a water-stop layer 21, and the water-stop layer 21 is filled with high-quality spherical clay.

The fan-shaped sand box 1 includes two side plates with a certain angle and an arc-shaped end plate. The two side plates are made of transparent acrylic material, and the angle range between the two side plates is 20-60°. In this embodiment, the side plates The included angle of the plates is 30°, the sides of the two side plates close to each other are connected to the well wall, and the end plates are connected to the sides of the two side plates away from each other, thus forming a fan-shaped box, in which the pumping and injection well 4 is located on the axis of the fan-shaped sand box 1.

Also be provided with a dividing plate in described fan-shaped sand box 1, described dividing plate is parallel with described end plate, dividing plate separates flow-stabilizing tank 2 and water-containing tank in fan-shaped sand box 1 (stabilizing tank 2 is dividing plate and cavity between the end plates), the flow-stabilizing tank 2 and the water-containing tank are respectively filled with a flow-stabilizing medium and a water-containing medium, and the flow-stabilizing medium and the water-containing medium constitute a flow-stabilizing layer and an aquifer respectively, and the aquifer The permeable holes communicate with the pumping and injection wells 4, and the separator is provided with a plurality of permeable holes, and the permeable holes communicate with the steady flow layer and the aquifer. In this embodiment, the aqueous medium is quartz with a particle size of 0.5mm Sand, the steady flow medium is preferably a mixture of quartz sand and gravel.

The fan-shaped sand box 1 is also provided with three sampling wells, and each sampling well is provided with a water-absorbing hose 20, and the upper end of the water-absorbing hose 20 extends out of the water-stop layer 21, and the three sampling wells are arranged along the radial line of the fan-shaped sand box 1 , adjacent sampling wells are equally spaced, in the present embodiment, the spacing of adjacent sampling wells is 60cm; the water suction hose 20 is used to extract water samples in the sampling wells during the experiment, so as to determine the water chemical characteristics of the water samples.

The radial refilling system includes a pumping tank 5, a solute tank 6, a refilling pipe 14 and a water pumping pipe 13. The solute tank 6 is equipped with an experimental solution, and the experimental solution can be set to iron and manganese ion solutions according to experimental needs. (iron ion solution, manganese ion solution, iron, manganese ion mixed solution); described pumping pipe 13 and refilling pipe 14 all extend in the described pumping water injection well 4, and described refilling pipe 14 and pumping pipe 13 are respectively connected with The pumping tank 5 is connected to the solute tank 6, and the refilling pipe 13 and the suction pipe 13 are provided with a water injection pump 17 and a water pump 16 respectively; , wherein the valve located on the suction pipe 13 is valve one 18, and the valve located on the return pipe 14 is valve two 19.

The overflow system includes an overflow device 8 and a lifting device 12, the overflow device 8 includes an overflow tank 9 and an outlet pipe 11, and the overflow tank 9 is connected to the bottom of the fan-shaped sand box 1 through the outlet pipe 11, and the overflow An overflow port 10 is provided at the bottom of the flow pool 9, and the outlet pipe 11 is a hose structure; the overflow device 8 is arranged on a lifting device 12, and the lifting device 12 is used to drive the overflow pool 9 to lift and adjust the overflow pool. 9 levels in height.

The data monitoring system includes a pressure measuring plate 7 on which a plurality of pressure measuring tubes 5 are arranged; the back side of the fan-shaped sand box 1 is provided with a plurality of pressure measuring holes arranged in an array, wherein a row of pressure measuring holes Each of the pressure measuring holes is connected to a pressure measuring tube through a connecting hose, and the remaining pressure measuring holes not connected to the pressure measuring tube are blocked. The multiple pressure measuring tubes on the pressure measuring plate 7 are used to measure the The water level from the multiple pressure measuring holes arranged up and down on the ground can detect the change of the water level in the whole aquifer in real time.

The suction pump 16 of the radial recharge system pumps the liquid in the water injection well 4 into the water suction tank 5, and the water injection pump 17 is used to inject the liquid in the solute tank 6 into the water injection well 4, and the suction pipe 13 and the return The flow meter 15 on the filling pipe 14 is used to measure the pumping volume and the refilling volume of the radial refilling system respectively.

The permeable holes at the bottom of the pumping and injecting well 4 are used to make the fluid in the pumping and injecting well 4 evenly enter the aquifer, so as to improve the saturation efficiency of the aquifer medium.

The flow stabilization medium in the flow stabilization tank 2 in the fan-shaped sand box 1 can exert a flow stabilization effect, so that the liquid flows out evenly, ensures the stability of the flow field, and avoids affecting the experimental results.

The lifting device 12 is used to adjust the level of the overflow pool 7 to ensure the stability of the water head in the supply fan-shaped sand box 1 .

The multiple pressure measuring tubes on the pressure measuring plate 7 are used to measure the water level at a plurality of pressure measuring holes arranged up and down on the same section, so as to detect the water level change in the whole aquifer in real time. The structure of the pressure measuring plate 7 has The advantages of simple operation and high feasibility of collected data.

The groundwater recharge chemical clogging simulation experiment method using the above-mentioned groundwater recharge chemical clogging simulation experiment device comprises the following steps:

S1: Observe and check whether the function of the experimental device is normal, perform exhaust operation on the pressure measuring plate 7, and connect the entire experimental device;

S2: Fill the fan-shaped sand box 1 with quartz sand with a particle size of 0.5 mm and compact it to form an aquifer, set a sampling well in the aquifer, and bury a suction hose 20 for collecting water samples during the experiment and Determination of water chemical characteristics of water samples;

S3: Prepare a specific concentration of iron-manganese ion solution, manganese ion solution or a mixed solution of the two, inject it into the solute box 6, to study the impact of different concentrations of experimental recharge water on groundwater recharge blockage;

S4: The water level of the overflow device is adjusted so that the liquid level of the overflow pool 9 is higher than the liquid level of the aquifer. The distilled water source is connected externally through the overflow device, and the distilled water is first injected into the steady flow tank, and gradually infiltrated after the water flow is stable. In the quartz sand in the aquifer, the water-containing medium is saturated with water and exhausted, and the permeability coefficient of the sand sample is measured at this time, and the recharge test is carried out after the value tends to be stable;

S5: After the water saturation operation is completed, open the valve 2 19 and the water injection pump 17 on the recharge pipe, and inject the experimental solution prepared in the solute tank 6 into the recharge well through the water injection pump 17. During the experiment, use the flow meter 15 to real-time Monitor the recharge volume and the water outlet flow of the overflow port 10, read and record the readings of the pressure measuring tubes on the pressure measuring plate 7, and at the same time, take water samples in the aquifer through the water suction hose 20 and perform water quality analysis to detect iron Manganese ion concentration and water quality parameters;

S6: Simulated refilling test: close the water injection pump 17 and valve two 19, open the water pump 16 and valve one 18, pump the solution in the fan-shaped sand box 1 into the water suction tank 5, and connect the water source through the overflow device during the pumping process. Evenly inject distilled water into the steady flow tank 2, enter the aquifer through the permeation hole, monitor the concentration of the water sample in the fan-shaped sand box 1, and end a recharge test when the concentration is consistent with the concentration of the solution in the saturated stage;

S7: Change the composition of the experimental solution, repeat the above steps S1-S6 several times under the condition of controlling variables, and compare the experimental results of each time.

In the present embodiment, repeat the above-mentioned steps S1-S6 three times (i.e. carry out four recharge tests altogether), the concentration that is made into four groups of comparative experiment solutions in the four recharge tests is: (1) Fe2+: 0mg/L, Mn2+: 3mg /L; (2) Fe2+: 4mg/L, Mn2+: 2mg/L; (3) Fe2+: 8mg/L, Mn2+: 1mg/L; (4) Fe2+: 12mg/L, Mn2+: 0mg/L.

The beneficial effect of a groundwater recharge chemical blockage simulation experiment device and its experimental method of the present invention is: the experimental device and method can simulate the radial recharge process of groundwater, and the recharge water can be studied by studying the different iron and manganese ion contents in the recharge water samples The clogging effect of chemical components on the recharge well, by changing the chemical properties of the recharge water, simulates the temporal and spatial changes of the solution concentration in the process of chemical clogging of groundwater recharge; and reveals the chemical composition of groundwater recharge through the migration and changes of the chemical components of the experimental solution. The clogging mechanism provides a scientific basis for improving the efficiency of groundwater recharge. Moreover, the device has complete structure, reasonable space layout, strong operability and controllable influencing factors.

In this article, the orientation words such as front, rear, upper, and lower involved are defined by the parts in the drawings and the positions between the parts in the drawings, just for the clarity and convenience of expressing the technical solution. It should be understood that the use of the location words should not limit the scope of protection claimed in this application.

In the case of no conflict, the above-mentioned embodiments and features in the embodiments herein may be combined with each other.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

1. The utility model provides an underground water recharge chemical blocking effect simulation experiment device which characterized in that: the system comprises a water injection system, a radial recharge system, an overflow system and data monitoring;

the radial recharging system comprises a fan-shaped sand box and a pumping and injection well; the bottom of the pumping and injection well is provided with a plurality of water permeable holes, and the pumping and injection well is vertically arranged at the axis of the fan-shaped sand box; the sector sand box is filled with a water-containing medium for forming a water-containing layer, and the water pumping and injecting well is communicated with the water-containing layer through a water permeable hole; three sampling wells are further arranged in the fan-shaped sand box, a water absorption hose is arranged in each sampling well, and the water absorption hoses are used for extracting a water sample in the water-containing layer to determine the water chemistry characteristics of the water sample;

the radial recharge system comprises a water pumping box, a solute box, a recharge pipe and a water pumping pipe, wherein an experimental solution is filled in the solute box, the water pumping pipe and the recharge pipe both extend into the water pumping and injecting well, the recharge pipe and the water pumping pipe are respectively connected with the solute box and the water pumping box, and the recharge pipe and the water pumping pipe are respectively provided with a water injection pump and a water pumping pump;

the overflow device comprises an overflow pool and a water outlet pipe, the overflow pool is connected with the bottom of the fan-shaped sand box through the water outlet pipe, and the bottom of the overflow pool is provided with an overflow port;

the data monitoring system comprises a pressure measuring plate, and a plurality of pressure measuring pipes are arranged on the pressure measuring plate; the side wall of the fan-shaped sand box is provided with a plurality of pressure measuring holes which are arranged in an array mode, one row of pressure measuring holes are respectively connected with a plurality of pressure measuring pipes through a plurality of pressure measuring pipes, and the pressure measuring pipes are used for measuring water level changes in the water-containing layer.

2. The underground water recharging chemical blocking effect simulation experiment device according to claim 1, characterized in that: the overflow tank is arranged on the lifting device, and the lifting device is used for adjusting the horizontal height of the overflow tank.

3. The underground water recharging chemical blocking effect simulation experiment device according to claim 1, characterized in that: the three sampling wells are arranged along the radius line of the fan-shaped sand box, the distance between every two adjacent sampling wells is equal, and the distance between every two adjacent sampling wells is 60cm.

4. The underground water recharging chemical blocking effect simulation experiment device according to claim 1, characterized in that: the pumping and injection well further comprises a well wall, a filter pipe, a settling pipe and filter materials, wherein the filter pipe is located in the well wall, the lower end of the filter pipe is provided with the settling pipe, the outer wall of the filter pipe and the inner wall of the well wall are filled with the filter materials forming a filter layer, the filter pipes are a plurality of the filter holes are distributed at equal intervals from top to bottom and the bottom of the well wall, and the top of the filter layer is provided with a water stop layer.

5. The underground water recharging chemical blocking effect simulation experiment device according to claim 1, characterized in that: the fan-shaped sand box comprises two side plates and an arc-shaped end plate, the two side plates are connected to the water pumping and injecting well, an included angle between the two side plates is 20-60 degrees, and the arc-shaped end plate is connected to the end portion of the side plate.

6. The underground water recharging chemical blocking effect simulation experiment device according to claim 5, characterized in that: the two side plates are acrylic plates.

7. The underground water recharging chemical blocking effect simulation experiment device according to claim 6, characterized in that: an arc-shaped baffle is further arranged in the fan-shaped sand box, a flow stabilizing groove is formed in the fan-shaped sand box through the baffle in a separated mode, a plurality of penetrating holes are distributed in the baffle, and a flow stabilizing medium is filled in the flow stabilizing groove.

8. The underground water recharging chemical blocking effect simulation experiment device according to claim 1, characterized in that: and valves and flowmeters are arranged on the recharge pipe and the water pumping pipe.

9. An underground water recharge chemical blocking effect simulation experiment method is characterized in that: the method uses an experimental device for simulating radial recharge of groundwater according to any one of claims 1 to 8, and comprises the following steps:

s1: observing and checking whether the function of the experimental device is normal, performing exhaust operation on the pressure measuring plate, and connecting the whole experimental device;

s2: filling a fan-shaped sand box with a water-containing medium, compacting, and burying a water-absorbing hose in the water-containing medium;

s3: preparing a ferro-manganese ion solution, a manganese ion solution or a mixed solution of the ferro-manganese ion solution and the manganese ion solution with specific concentration to study the influence of experimental recharge water with different concentrations on groundwater recharge blockage,

s4: adjusting the water level of the overflow device to enable the liquid level of the overflow pool to be higher than the liquid level of the aquifer, externally connecting a distilled water source through the overflow device, injecting distilled water into the flow stabilizing tank, gradually permeating the water into quartz sand in the aquifer after the water flow is stabilized, saturating and exhausting the water-containing medium, measuring the permeability coefficient of the sand sample at the moment, and performing a recharge test after the value of the permeability coefficient tends to be stable;

s5: and after the water saturation operation is finished, opening a valve II and a water injection pump on the recharge pipe, injecting the prepared experiment solution in the solute box into the recharge well through the water injection pump respectively, monitoring the recharge quantity and the water outlet flow of an overflow port in real time by using a flowmeter in the experiment process, reading and recording the readings of each pressure measuring pipe on a pressure measuring plate, extracting water samples in the aquifer at intervals, analyzing the water quality, and detecting the concentration of iron and manganese ions and the water quality parameters.

S6: simulating a water pumping test: closing a water injection pump and a valve II, opening a water suction pump and a valve I, pumping the solution in the sand box into a water suction box, connecting an external water source through an overflow device in the pumping process, uniformly injecting distilled water into a flow stabilizing groove, allowing the distilled water to enter a water-bearing stratum through a permeation hole, monitoring the concentration of a water sample in the sand box, and ending a recharge test when the concentration of the water sample is consistent with the concentration of the solution in the water saturation stage;

s7: and (4) testing the components of the solution, repeating the steps S1-S6 for multiple times under the condition of controlling variables, and comparing the test results.

10. The underground water recharge chemical blockage effect simulation experiment method according to claim 1, which is characterized in that: repeating S1-S6 three times in the step S7, wherein four groups of comparative experiment solutions prepared in the four recharging experiments have the following concentrations: fe ²⁺ ：0mg/L，Mn ²⁺ ：3mg/L；Fe ²⁺ ：4mg/L，Mn ²⁺ ：2mg/L；Fe ²⁺ ：8mg/L，Mn ²⁺ ：1mg/L；Fe ²⁺ ：12mg/L，Mn ²⁺ ：0mg/L。

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