Method for controlling and repairing diffusion of coastal aquifer organic pollutants to seawater

Abstract

The invention provides a method for controlling and repairing diffusion of coastal aquifer organic pollutants to seawater. The method comprises the following steps: 1) determining the conductivity of coastal underground water in a polluted region and the conductivity of seawater in a sea area; 2) dividing an adjacent-sea underground water area and a sea water area communicated with the adjacent-sea underground water area into a land-side area, a sea-side area and a salt ion overlapping area; 3) based on the adsorption coefficient grading of the organic pollutants and the biodegradability grading of the organic pollutants, a salt ion overlap region is expanded to the inland side and determined as an organic pollutant overlap region, the region, extending to the inland, of the organic pollutant overlap region is a landside pollution region, and the region, extending to the sea area, of the organic pollutant overlap region is a seaside pollution region; 4) tracing according to pollution data of the landside pollution area; an organic pollutant adsorption device is arranged in the organic pollutant overlapping area for adsorption repair; and according to the pollution data of the pollution area near the sea side, determining whether to carry out reinforced repair and / or continuous monitoring.

Description

Technical Field

[0001] The present invention relates to the field of organic pollutant treatment, and in particular to a method for controlling and repairing the diffusion of organic pollutants from coastal aquifers into seawater. Background Art

[0002] There are many petrochemical enterprises near the sea, and due to their own organic matter content and toxicity reserves, there is a great risk of organic pollution in groundwater. Some coastal petrochemical enterprises are as close as tens of meters from the coastline. Once groundwater is polluted, it is easily affected by tides and enters the sea, which leads to uncontrollable pollution. In addition, most pollution remediation and treatment adopts the method of finding the source first and then repairing it. This method delays the pollution control time and is relatively difficult to trace the source of complex groundwater flow fields near the sea.

[0003] In addition, there are many common groundwater pollution remediation technologies, including adsorption, extraction, PRB, chemical oxidation, etc., but there is no clear description for the remediation of organic pollution in coastal aquifers. The remediation methods based on adsorption basically use multi-layer adsorption or develop efficient modified adsorption materials to improve the adsorption effect. For example, Chinese patent CN216513145U proposes an adsorption device for groundwater remediation, which uses a three-layer adsorption plate to increase the contact time of pollutants and improve the adsorption efficiency. There are many articles and patents on the modification of adsorption materials, including activated carbon, zeolite, sponge, etc.

[0004] In summary, coastal petroleum and petrochemical enterprises face a high risk of organic pollution. The migration patterns of organic matter in aquifers are complex due to tidal dynamics, which is different from the one-way migration inland, making it difficult to control. Summary of the invention

[0005] One of the present inventions provides a method for controlling and repairing the diffusion of organic pollutants from a coastal aquifer into seawater, which comprises the following steps:

[0006] 1) Determine the conductivity of groundwater near the sea and the conductivity of seawater in the contaminated area;

[0007] 2) Based on the electrical conductivity of the coastal groundwater and the electrical conductivity of the seawater, the coastal groundwater area and the seawater area connected thereto are divided into a landside area whose electrical conductivity is equal to that of the coastal groundwater, a seaside area whose electrical conductivity is equal to that of the seawater, and a salt ion overlap area between the landside area and the seaside area whose electrical conductivity is greater than that of the coastal groundwater and less than that of the seawater;

[0008] 3) determining the types of organic pollutants in the polluted area, then determining the organic compound adsorption coefficients of the organic pollutants, and classifying the organic compound adsorption coefficients; determining the biodegradability of the organic pollutants, and classifying the biodegradability of the organic pollutants;

[0009] Based on the classification of the adsorption coefficient of organic compounds and the classification of the biodegradability of organic pollutants, the distance range of the salt ion overlap zone is expanded inland and determined as the organic pollutant overlap zone, the area outside the organic pollutant overlap zone and extending inland is determined as the land-side pollution zone, and the area outside the organic pollutant overlap zone and extending to the sea is determined as the sea-side pollution zone;

[0010] 4) For the land-side polluted area, tracing the pollution data of the land-side polluted area to find out the pollution source;

[0011] For the organic pollutant overlapping area, an organic pollutant adsorption device is arranged in the organic pollutant overlapping area to perform adsorption and remediation until the requirements are met;

[0012] For the polluted area on the sea side, whether to carry out enhanced restoration and / or continuous monitoring is determined based on the pollution data of the polluted area on the sea side.

[0013] In one specific embodiment, in step 3), the organic compound adsorption coefficient is divided into three levels, level I: greater than 0 and less than or equal to 10, level II: greater than 10 and less than or equal to 100, level III: greater than 100;

[0014] The biodegradability of the organic pollutants is divided into four levels: A: greater than 0 and less than or equal to 0.1, B: greater than 0.1 and less than or equal to 0.15, C: greater than 0.15 and less than or equal to 0.5, and D: greater than 0.5;

[0015] in,

[0016] When the organic compound adsorption coefficient is classified as level I and the biodegradability of the organic pollutant is classified as any one of the four levels, the salt ion overlap zone is expanded by 2 meters;

[0017] When the organic compound adsorption coefficient is classified as Class II and the biodegradability of the organic pollutant is classified as Class C or Class D, the salt ion overlap zone is expanded by 2 meters;

[0018] When the organic compound adsorption coefficient is classified as Class II and the biodegradability of the organic pollutant is classified as Class A or Class B, the salt ion overlap zone is expanded by 5 meters;

[0019] When the organic compound adsorption coefficient is classified as Class III and the biodegradability of the organic pollutant is classified as Class C or Class D, the salt ion overlap zone is expanded by 5 meters;

[0020] When the organic compound adsorption coefficient is classified as Class III and the biodegradability of the organic pollutant is classified as Class A or Class B, the salt ion overlap zone is expanded by 8 meters.

[0021] In a specific embodiment, in step 4), for the land-side polluted area, the pollution data of the land-side polluted area is modeled using GMS software to invert the pollution source, thereby finding the pollution source.

[0022] In one specific embodiment, in step 4), for the organic pollutant overlap zone, the diffusion distance D of the organic pollutants under the action of tidal water dynamics in one tidal cycle is calculated using formula a).

[0023] D=12960KI a)

[0024] Wherein, K is the velocity of water in the aquifer (i.e., groundwater velocity), in cm / s, which can be determined based on the Hydrogeological Model Guide; I is the topographic relief;

[0025] Taking the width of the organic pollutant overlap region as W, calculate the value N of D / W / 2. When N is less than or equal to 1, a single row of wells is set in the organic pollutant overlap region. When N is greater than 1 and N is an integer, N rows of wells are set in the organic pollutant overlap region. When N is greater than 1 and N is a decimal, N+1 rows of wells are set in the organic pollutant overlap region.

[0026] An organic pollutant adsorbing material is arranged in the well to form an organic pollutant adsorbing device.

[0027] In a specific embodiment, I=h / W, wherein h is the hydraulic head difference of the organic pollutant overlapping region, and W is the width of the organic pollutant overlapping region.

[0028] In a specific embodiment, the organic pollutant adsorbing material is carbon fiber and zeolite.

[0029] In a specific embodiment, the volume ratio of the carbon fiber to the zeolite is 3:1 to 4:1.

[0030] In a specific embodiment, in step 4), for the polluted area on the sea side, if the pollution data of the polluted area on the sea side shows that it is lower than the HJ14848 standard, the polluted area on the sea side is subjected to long-term monitoring.

[0031] In a specific embodiment, in step 4), for the polluted area on the sea side, if the pollution data of the polluted area on the sea side shows that it is higher than the HJ14848 standard, the polluted area on the sea side is subjected to enhanced restoration.

[0032] In a specific embodiment, during the enhanced remediation, water from the polluted area on the sea side is pumped out before the seawater reaches high tide, and before the seawater reaches low tide, a biological agent for degrading organic pollutants and / or an electron acceptor slow-release preparation for stimulating the growth of microorganisms in the groundwater in the polluted area on the sea side is injected in situ, thereby improving the degradation efficiency of organic pollutants. The electron acceptor may be oxygen, nitrate, sulfate, etc.

[0033] In a specific embodiment, a groundwater extraction pump is used to extract water from the polluted area on the sea side, wherein the extraction begins 3 hours before high tide and continues until the high tide reaches the highest point.

[0034] In a specific embodiment, the biological agent and / or the sustained-release preparation is injected in situ using a jet drill, wherein the injection begins 3 hours before the lowest tide and continues until the tide reaches the lowest point of the low tide.

[0035] Beneficial effects of the present invention:

[0036] Some coastal petroleum and petrochemical enterprises are tens of meters away from the sea, and the risk of organic pollution in groundwater is high. In addition, due to the periodic changes in the groundwater flow field affected by the tide, organic pollution continues to return, the migration pattern is complex, and management is very difficult. The high cost of repair also imposes a large economic burden on the enterprise. The present invention actively utilizes tidal power, divides the complex organic pollutant migration process into zones, and uses the zones to trace the source of pollution, adsorb and repair, and strengthen repair respectively. With the full use of natural power, the repair can achieve twice the result with half the effort. There is no large-scale project itself, the cost is low, the safety is high, and the social impact is small. It can effectively improve the level of groundwater organic pollution prevention and control in coastal enterprises.

[0037] This invention is the first to closely combine the hydrodynamics generated by the interaction between tides and regional flow fields with the remediation technology of organic pollutants. The reciprocating motion of groundwater in the coastal aquifer can effectively increase the contact area and time of organic pollutants on the adsorption material, achieving twice the result with half the effort, greatly reducing power costs and improving adsorption efficiency. Common extraction technologies, material microbial agent injection technologies, etc. all need to flow with groundwater after injection. If combined with the power of the tide itself, it can effectively reduce energy consumption and expand the radius of action.

[0038] The present invention finds that the reciprocating action of the overlapping area of ​​pollution is a good working condition for adsorption, which can effectively increase the contact time of pollutants and improve the adsorption effect. Therefore, according to the characteristics of pollutant migration, this patent uses tidal power to target the organic pollution of groundwater in coastal enterprises, divides the coastal aquifer into zones, identifies the salinity transition zone (i.e., the salt ion overlapping zone), determines the location of the overlapping area of ​​organic pollutants, and uses the method of building wells and placing adsorbent materials in the overlapping area for adsorption, making full use of the periodically changing flow field without additional power, and the pollution is continuously adsorbed and disposed in the reciprocating motion. The adsorbent material selects activated carbon fiber with a certain supporting force and zeolite with a density greater than water that is not easy to desorb, to ensure the overall well state of the adsorbent material. For the sea-side pollution area outside the overlapping area of ​​organic pollutants, if it exceeds the standard, the phased extraction and material injection with the help of tidal power are adopted to increase the technical coverage area and achieve twice the result with half the effort. The land-side pollution area is directly generalized as a one-way pollution migration process, and the complex migration process is divided into blocks, and measures are taken separately, which is an effective groundwater control technology for organic pollution in coastal aquifers.

[0039] The present invention aims at the organic pollution of groundwater that may occur in coastal petroleum and petrochemical enterprises. It uses the power of the change of groundwater flow field caused by tides to cut and analyze the complex migration process of organic pollutants and treat them one by one. The location of the overlapping area of ​​organic pollutants, which is an area of ​​reciprocating pollution migration, is determined, and adsorption technology is used to repair this area without additional power. The adsorption effect is improved by the reciprocating movement of pollutants; the part of the pollution area on the sea side that exceeds the standard is strengthened for pollution remediation, and extraction or injection is carried out according to the change of tidal power, which greatly increases the treatment coverage area; the pollution area on the land side is directly generalized as a simple one-dimensional unidirectional migration, and software simulation prediction is used for tracing the source. The whole chain is repaired and treated separately, which achieves twice the result with half the effort. This patent effectively improves the groundwater risk management and control capabilities of coastal enterprises.

[0040] Since the research on the remediation of organic pollutants in groundwater is mainly focused on the development and application of single technologies, mainly relying on artificial power, etc., there is less use of changes in groundwater flow fields, and the role of natural power such as tides is ignored, which often results in half the effort with twice the results. In addition, there is currently no mature technical system for the remediation of coastal aquifers with complex migration patterns of organic pollutants. Therefore, the present invention combines the characteristics of groundwater flow field changes in coastal aquifers, divides the aquifers into zones and blocks according to the migration process of organic pollutants, carries out remediation / tracing / monitoring in blocks, breaks down complex problems, and uses low-cost technology with the help of tidal power to effectively achieve pollution control. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram showing the migration process of organic pollutants in coastal groundwater.

[0042] Figure 2 A flow chart of the method of the present invention is shown.

[0043] Figure 3 It shows that the coastal aquifer can be divided into the land-side pollution zone, the sea-side pollution zone and the organic pollutant overlapping zone for zoning restoration. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with examples, but the examples of the present invention are only exemplary descriptions, and the implementation methods do not constitute limitations of the present invention under any circumstances.

[0045] Based on the Technical Guidelines for Risk Assessment of Contaminated Sites (HJ 25.3-2014), the adsorption coefficient of organic compounds (KOC) is determined and divided into three levels: Level I: greater than 0 and less than or equal to 10 cm 3 / g, Grade II: greater than 10cm 3 / g and less than or equal to 100cm 3 / g, Class III: greater than 100cm 3 / g.

[0046] The biodegradability of organic pollutants can be expressed by the BOD5 / COD value, which is obtained by sampling and measuring in the polluted area. It is divided into four levels: Class A: greater than 0 and less than or equal to 0.1, Class B: greater than 0.1 and less than or equal to 0.15, Class C: greater than 0.15 and less than or equal to 0.5, and Class D: greater than 0.5.

[0047] Based on the KOC classification and the biodegradability classification of organic pollutants, the distance extending inland is determined to expand the scope of the salt ion overlap zone, thereby determining the scope of the organic pollutant overlap zone. The specific distance extending inland is shown in Table 1 below.

[0048] Table 1

[0049]

[0050] Example 1

[0051] A petrochemical enterprise 52m away from the sea experienced organic pollution of groundwater and urgently needed to be controlled.

[0052] 1) Determine that the groundwater conductivity in the area is 0.12S / m and the seawater conductivity is 4S / m.

[0053] 2) First, according to the above conductivity values, the coastal aquifer is divided into three areas, namely the landside area, the salt ion overlap area and the seaside area. The area with a conductivity of 0.12S / m is the landside area, the area with a conductivity of 0.12S / m to 4S / m is the salt ion overlap area, and the area with a conductivity of 4S / m is the seaside area. The final result: based on the coastline, the area extending within 10m inland is the seaside area, the area extending from 10m to 30m inland is the salt ion overlap area, and the area extending 30m inland to the plant area is the landside area.

[0054] 3) After sampling the groundwater near the petrochemical enterprise, it was found that the groundwater was polluted and the organic pollutant was toluene. According to the Technical Guidelines for Risk Assessment of Contaminated Sites (HJ 25.3-2014), the KOC of toluene is 234cm 3 / g, the level is III; after measurement, BOD5 / COD is 0.102, and the biodegradability level of organic matter is B. According to Table 1, still based on the coastline, the scope of the salt ion overlap zone is expanded by 8m inland, so as to determine the scope of the organic pollutant overlap zone: based on the coastline, extending 10m to 38m inland; within 10m inland is the sea-side pollution zone, and extending 38m inland to the factory area is the land-side pollution zone.

[0055] 4) For the land-side pollution area, based on the pollution data, the land-side pollution process was generalized as a one-way process, and the data of the land-side pollution area was used to use GMS software to model and predict the pollution source. The results indicated that a certain aromatics unit was a suspected pollution source;

[0056] For the organic pollutant overlap zone, first use formula a) to calculate the distance D of the simple hydrodynamic diffusion of organic pollutants in a spring tide cycle (15 days).

[0057] D=12960KI a)

[0058] The above formula is obtained by converting D=15×3600×24 / 100KI, 15 is the number of days of the spring tide cycle, 3600 is the conversion of hours to seconds, 24 is the conversion of days to hours, 100 is the conversion of meters to centimeters, K is the flow rate of groundwater in the aquifer, determined based on the "Hydrogeological Model Guide", the unit is cm / s, and in this embodiment K=3cm / s; I is a hydrogeological parameter, that is, the terrain undulation, wherein I=h / W, h is the head difference in the overlapping area of ​​the organic pollutants, the unit is meter, in this embodiment, it is 0.056 meters, W is the width of the overlapping area of ​​the organic pollutants, the unit is meter, in this embodiment, it is 28 meters, and in this embodiment, I=2‰;

[0059] It is calculated that D = 77.76m; since D = 77.76m is much larger than the width W = 28 meters of the organic pollutant overlap zone determined above, a single row of wells can be directly set up in the organic pollutant overlap zone to meet the remediation requirements. After the wells are laid, an adsorption device composed of carbon fiber and zeolite is placed in the well. The adsorption device adopts a cylindrical filling combination, with 80% of the volume of carbon fiber as the skeleton to prepare a cylindrical shape. After the carbon fiber is prepared into a cylindrical skeleton, 20% of the volume of zeolite is added thereto, so that the zeolite is interspersed in the carbon fiber skeleton. Based on the adsorption capacity of the adsorption device and the degree of pollution in the organic pollutant overlap zone, the adsorption device is replaced when it is saturated or nearly saturated;

[0060] For the polluted area near the sea, before the organic pollutant overlapping area is repaired, the concentration of organic pollutants within 3 meters of the organic pollutant overlapping area is tested. After testing, the concentration of organic pollutants meets the requirements of Class IV water in the HJ14848 standard. Therefore, only long-term monitoring is required, that is, testing once every quarter.

[0061] 5) After 6 months of adsorption of organic pollutants in the overlapping area, the restoration was suspended to test the restoration effect, that is, to detect the concentration of organic pollutants in the polluted area near the sea. That is, after another high tide, the concentration of organic pollutants within 3 meters near the overlapping area of ​​organic pollutants in the polluted area near the sea was measured. The result was 20% of the concentration before restoration and met the requirements of Class IV water in the HJ14848 standard. It can be seen that the restoration has taken effect and can be stopped.

[0062] Example 2

[0063] A petrochemical enterprise 130m from the sea experienced organic pollution of groundwater and urgently needed to be controlled.

[0064] 1) Determine that the groundwater conductivity in the area is 700μS / cm and the seawater conductivity is 4.5S / m.

[0065] 2) First, according to the above conductivity values, the coastal aquifer is divided into three areas, namely the landside area, the salt ion overlap area and the seaside area. The area with a conductivity of 700μS / cm is the landside area, the area with a conductivity of 700μS / cm to 4.5S / m is the salt ion overlap area, and the area with a conductivity of 4.5S / m is the seaside area. The final result: based on the coastline, the area within 30m inland is the seaside area, the area extending from 30m to 90m inland is the salt ion overlap area, and the area extending from 90m inland to the plant area is the landside area.

[0066] 3) After sampling the groundwater near the petrochemical enterprise, it was found that the groundwater was polluted and the organic pollutant was aniline. According to the Technical Guidelines for Risk Assessment of Contaminated Sites (HJ 25.3-2014), the KOC of aniline was 70.2 cm 3 / g, the level is II; after measurement, BOD5 / COD is 0.73, and the biodegradability level of organic matter is A. According to Table 1, still based on the coastline, the scope of the salt ion overlap zone is expanded by 5m inland, so as to determine the scope of the organic pollutant overlap zone: based on the coastline, extending 30m to 95m inland; within 30m inland is the sea-side pollution area, and extending 95m inland to the factory area is the land-side pollution area.

[0067] 4) For the land-side pollution area, based on the pollution data, the land-side pollution process was generalized as a one-way process. The data of the land-side pollution area was used to use the GMS software to model and predict the pollution source. The results indicated that a certain ethylene unit was a suspected pollution source;

[0068] For the organic pollutant overlap zone, firstly use formula a) to calculate the distance D of the organic pollutant's simple hydrodynamic diffusion in a spring tide cycle (15 days).

[0069] D=12960KI a)

[0070] Wherein, K is the velocity of groundwater in the aquifer, determined based on the "Guide to Hydrogeological Models", in cm / s, and in this embodiment, K=0.3 cm / s; I is a hydrogeological parameter, i.e., terrain relief, wherein I=h / W, h is the head difference in the overlapping area of ​​organic pollutants, in meters, in this embodiment, h=0.065 meters, W is the width of the overlapping area of ​​organic pollutants, in meters, in this embodiment, W=65 meters, and in this embodiment, I=1‰;

[0071] It is calculated that D = 3.89m. Therefore, the coverage area for organic pollutant remediation using tidal power is relatively small, (95m-30m) / 3.89 / 2 = 8.35. Therefore, at least 9 rows of adsorption wells need to be set up to meet the remediation requirements. After the wells are laid, an adsorption device composed of carbon fiber and zeolite is placed in the well. Among them, the adsorption device adopts a cylindrical filling combination, with 75% volume of carbon fiber as the skeleton prepared into a cylindrical shape. After the carbon fiber is prepared into a cylindrical skeleton, 25% volume of zeolite is added thereto, so that the zeolite is interspersed in the carbon fiber skeleton. Based on the adsorption capacity of the adsorption device and the degree of pollution in the overlapping area of ​​organic pollutants, the adsorption device is replaced regularly when it is saturated or close to saturation;

[0072] For the polluted area near the sea, before the organic pollutant overlap area was repaired, the concentration of organic pollutants within 3 meters of the organic pollutant overlap area was tested. The result showed that the concentration of organic pollutants did not meet the requirements of Class IV water in the HJ14848 standard. Therefore, it was necessary to strengthen the repair by adopting the technical means of extraction, starting with pumping water 3 hours before high tide until the tide reached its peak for enhanced repair.

[0073] 5) After the organic pollutant overlap area was adsorbed for 5 months and the pollution area near the sea was extracted for the same period of time, the repair was suspended to test the repair effect, that is, to detect the concentration of organic pollutants in the pollution area near the sea. That is, after another high tide, the concentration of organic pollutants within 3 meters near the organic pollutant overlap area in the pollution area near the sea was measured. The result was 5% of the concentration before the repair and met the requirements of Class IV water in the HJ14848 standard. It can be seen that the repair is effective and can be stopped.

[0074] Example 3

[0075] A petrochemical enterprise 100m from the sea experienced organic pollution of groundwater and urgently needed to be controlled.

[0076] 1) The groundwater conductivity in the area was determined to be 650 μS / cm and the seawater conductivity was 4 S / m.

[0077] 2) First, according to the above conductivity values, the coastal aquifer is divided into three areas, namely the land side area, the salt ion overlap area and the sea side area. The area with a conductivity of 650μS / cm is the land side area, the area with a conductivity between 650μS / cm and 4S / m is the salt ion overlap area, and the area with a conductivity of 4S / m is the sea side area. The final result is: based on the coastline, the area extending within 20m inland is the sea side area, the area extending from 20m to 50m inland is the salt ion overlap area, and the area extending 50m inland to the plant area is the land side area.

[0078] 3) After sampling the groundwater near the petrochemical enterprise, it was found that the groundwater was polluted and the organic pollutant was benzene. According to the Technical Guidelines for Risk Assessment of Contaminated Sites (HJ 25.3-2014), the KOC of benzene is 146cm 3 / g, the level is III; after measurement, BOD5 / COD is 0.163, and the biodegradability level of organic matter is B. According to Table 1, still based on the coastline, the scope of the salt ion overlap zone is expanded by 8m inland, so as to determine the scope of the organic pollutant overlap zone: based on the coastline, extending 20m to 58m inland; within 20m inland is the sea-side pollution area, and extending 58m inland to the factory area is the land-side pollution area.

[0079] 4) For the land-side pollution area, based on the pollution data, the land-side pollution process was generalized as a one-way process. The data of the land-side pollution area was used to use GMS software to model and predict the pollution source. The results indicated that a certain aromatics tank was a suspected pollution source;

[0080] For the organic pollutant overlap zone, firstly use formula a) to calculate the distance D of the organic pollutant's simple hydrodynamic diffusion in a spring tide cycle (15 days).

[0081] D=12960KI a)

[0082] Wherein, K is the velocity of groundwater in the aquifer, determined based on the "Hydrogeological Model Guide", in cm / s, in this embodiment, K=0.03 cm / s; I is a hydrogeological parameter, i.e., terrain relief, wherein I=h / W, h is the head difference in the organic pollutant overlap zone, in meters, in this embodiment, h=0.072 meters, W is the width of the organic pollutant overlap zone, in meters, in this embodiment, W=38 meters, in this embodiment, I=2‰;

[0083] It is calculated that D = 0.78m. Therefore, the coverage area of ​​organic pollutant remediation using tidal power is relatively small, (58m-20m) / 0.78 / 2=24.35. Therefore, at least 25 rows of adsorption wells are required to meet the remediation requirements. After the wells are laid, an adsorption device composed of carbon fiber and zeolite is placed in the well. Among them, the adsorption device adopts a cylindrical filling combination, with 77% volume of carbon fiber as the skeleton prepared into a cylindrical shape. After the carbon fiber is prepared into a cylindrical skeleton, 23% volume of zeolite is added thereto, so that the zeolite is interspersed in the carbon fiber skeleton. Based on the adsorption capacity of the adsorption device and the degree of pollution in the overlapping area of ​​organic pollutants, the adsorption device is replaced regularly when it is saturated or close to saturation;

[0084] For the polluted area near the sea, before the organic pollutant overlap area is repaired, the concentration of organic pollutants within 3 meters of the organic pollutant overlap area is tested. The result shows that the concentration of organic pollutants does not meet the requirements of Class IV water in the HJ14848 standard. Therefore, it is necessary to strengthen the repair by injecting biological bacteria agents for repairing organic pollutants. The injection starts 3 hours before the lowest tide and continues until the tide reaches the lowest point of the low tide.

[0085] 5) After 3 months of adsorption of the overlapping area of ​​organic pollutants and the same period of biological remediation of the pollution area near the sea, the remediation was suspended to test the remediation effect, that is, to detect the concentration of organic pollutants in the pollution area near the sea. That is, after another high tide, the concentration of organic pollutants within 3 meters near the overlapping area of ​​organic pollutants in the pollution area near the sea was measured. The result was 52% of the concentration before remediation and did not meet the requirements of Class IV water in the HJ14848 standard. The remediation requirements were not met, and it was necessary to continue to replace the adsorption device and invest in biological agents for remediation of organic pollutants. After another 2 months, the remediation was suspended to test the remediation effect, that is, after another high tide, the concentration of organic pollutants within 3 meters near the overlapping area of ​​organic pollutants in the pollution area near the sea was measured. The result was 12% of the concentration before remediation and met the requirements of Class IV water in the HJ14848 standard. The remediation effect was achieved and the remediation was terminated.

[0086] Although the present invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that various changes may be made without departing from the true spirit and scope of the present invention. In addition, the subject matter, spirit and scope of the present invention may be varied to accommodate specific situations, materials, material combinations and methods. All of these changes are included within the scope of the claims of the present invention.

Claims

1. A method for controlling and repairing the diffusion of organic pollutants from a coastal aquifer into seawater, comprising the following steps: 1) Determine the conductivity of groundwater near the sea and the conductivity of seawater in the contaminated area; 2) Based on the electrical conductivity of the coastal groundwater and the electrical conductivity of the seawater, the coastal groundwater area and the seawater area connected thereto are divided into a landside area whose electrical conductivity is equal to that of the coastal groundwater, a seaside area whose electrical conductivity is equal to that of the seawater, and a salt ion overlap area between the landside area and the seaside area whose electrical conductivity is greater than that of the coastal groundwater and less than that of the seawater; 3) determining the types of organic pollutants in the polluted area, then determining the organic compound adsorption coefficients of the organic pollutants, and classifying the organic compound adsorption coefficients; determining the biodegradability of the organic pollutants, and classifying the biodegradability of the organic pollutants; Based on the classification of the adsorption coefficient of organic compounds and the classification of the biodegradability of organic pollutants, the distance range of the salt ion overlap zone is expanded inland and determined as the organic pollutant overlap zone, the area outside the organic pollutant overlap zone and extending inland is determined as the land-side pollution zone, and the area outside the organic pollutant overlap zone and extending to the sea is determined as the sea-side pollution zone; 4) For the land-side polluted area, tracing the pollution data of the land-side polluted area to find out the pollution source; For the organic pollutant overlapping area, an organic pollutant adsorption device is arranged in the organic pollutant overlapping area to perform adsorption and remediation until the requirements are met; For the polluted area on the sea side, whether to carry out enhanced restoration and / or continuous monitoring is determined based on the pollution data of the polluted area on the sea side.

2. The control and repair method according to claim 1, characterized in that: In step 3), the organic compound adsorption coefficient is divided into three levels: level I: greater than 0 and less than or equal to 10, level II: greater than 10 and less than or equal to 100, and level III: greater than 100; The biodegradability of the organic pollutants is divided into four levels: A: greater than 0 and less than or equal to 0.1, B: greater than 0.1 and less than or equal to 0.15, C: greater than 0.15 and less than or equal to 0.5, and D: greater than 0.5; in, When the organic compound adsorption coefficient is classified as level I and the biodegradability of the organic pollutant is classified as any one of the four levels, the salt ion overlap zone is expanded by 2 meters; When the organic compound adsorption coefficient is classified as Class II and the biodegradability of the organic pollutant is classified as Class C or Class D, the salt ion overlap zone is expanded by 2 meters; When the organic compound adsorption coefficient is classified as Class II and the biodegradability of the organic pollutant is classified as Class A or Class B, the salt ion overlap zone is expanded by 5 meters; When the organic compound adsorption coefficient is classified as Class III and the biodegradability of the organic pollutant is classified as Class C or Class D, the salt ion overlap zone is expanded by 5 meters; When the organic compound adsorption coefficient is classified as Class III and the biodegradability of the organic pollutant is classified as Class A or Class B, the salt ion overlap zone is expanded by 8 meters.

3. The control and repair method according to claim 1, characterized in that: In step 4), for the land-side pollution area, the pollution data of the land-side pollution area is modeled using GMS software to invert the pollution source, so as to find out the pollution source.

4. The control and repair method according to claim 1, characterized in that: In step 4), for the organic pollutant overlap zone, the diffusion distance D of the organic pollutants under the action of tidal water dynamics in one tidal cycle is calculated using formula a). D=12960KI a) Where K is the velocity of water in the aquifer, in cm / s; I is the topographic relief; Taking the width of the organic pollutant overlap region as W, calculate the value N of D / W / 2. When N is less than or equal to 1, a single row of wells is set in the organic pollutant overlap region. When N is greater than 1 and N is an integer, N rows of wells are set in the organic pollutant overlap region. When N is greater than 1 and N is a decimal, N+1 rows of wells are set in the organic pollutant overlap region. An organic pollutant adsorbing material is arranged in the well to form an organic pollutant adsorbing device.

5. The control and repair method according to claim 4, characterized in that: I=h / W, wherein h is the water head difference in the overlapping area of ​​the organic pollutants, and W is the width of the overlapping area of ​​the organic pollutants.

6. The control and repair method according to claim 4, characterized in that: The organic pollutant adsorbing materials are carbon fiber and zeolite.

7. The control and repair method according to claim 6, characterized in that: The volume ratio of the carbon fiber to the zeolite is 3:1 to 4:

1.

8. The control and repair method according to claim 1, characterized in that: In step 4), for the pollution area on the sea side, if the pollution data of the pollution area on the sea side shows that it is lower than the HJ14848 standard, the pollution area on the sea side is subject to long-term monitoring.

9. The control and repair method according to claim 1, characterized in that: In step 4), for the polluted area on the sea side, if the pollution data of the polluted area on the sea side shows that it is higher than the HJ14848 standard, the polluted area on the sea side is subjected to enhanced restoration.

10. The control and repair method according to claim 9, characterized in that: During the enhanced remediation, water from the seaside contaminated area is pumped out before the seawater reaches high tide, and biological agents for degrading organic pollutants and / or electron acceptor slow-release preparations for stimulating the growth of microorganisms in the groundwater in the seaside contaminated area are injected in situ before the seawater reaches low tide, thereby improving the degradation efficiency of organic pollutants.

11. The control and repair method according to claim 10, characterized in that: A groundwater extraction pump is used to extract water from the polluted area on the sea side, wherein the extraction begins 3 hours before high tide and continues until the high tide reaches the highest point.

12. The control and repair method according to claim 10, characterized in that: The biological agent and / or the sustained-release preparation is injected in situ using a jet drill, wherein the injection begins 3 hours before the lowest tide until the tide reaches the lowest point of the low tide.

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