Method for repairing chlorohydrocarbon pollution, chlorohydrocarbon pollution repairing agent and application

Abstract

The invention relates to the technical field of environmental remediation, and particularly discloses a method for remedying chlorinated hydrocarbon pollution, a chlorinated hydrocarbon pollution remediation agent and application, and the method comprises the steps that an injection point is arranged on a chlorinated hydrocarbon pollution site; preparing a sodium persulfate solution with the mass concentration of 7.5%-15%, and preparing a mixed solution of ferrous sulfate with the mass concentration of 1.6%-3.2% and sodium pyrophosphate with the mass concentration of 1.25%-2.5%, namely an iron pyrophosphate mixed solution; drilling is carried out according to the set injection points, drilling is carried out to the pollution depth of the chlorinated hydrocarbon pollution site, and a sodium persulfate solution is sprayed from deep to shallow; spraying a ferric pyrophosphate mixed solution in the same manner, after 7-14 days of chemical oxidation remediation, spraying 5-10 L of emulsified vegetable oil, and naturally remediating for 30-35 days. According to the method, the concentration of chlorohydrocarbon pollutants in chlorohydrocarbon polluted site soil and underground water is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental remediation, in particular to a method for remediating chlorinated hydrocarbon pollution, a chlorinated hydrocarbon pollution remediation agent and application. BACKGROUND

[0002] Chlorinated hydrocarbons are a class of synthetic organic chlorides used in industrial and agricultural production activities, including chlorinated alkanes, chlorinated alkenes and chlorinated aromatic hydrocarbons. Due to the thermal stability and chemical stability of the negatively charged chlorine atom, chlorinated hydrocarbons are widely used in the fields of medicine, chemical industry, electronics, leather, etc. Common industrial products include herbicides, solvents, flame retardants and dry cleaning agents, etc. Most chlorinated hydrocarbons belong to persistent organic pollutants, which have carcinogenic, teratogenic and mutagenic "three toxic" effects, biological accumulation and long-distance migration.

[0003] Iron-activated persulfate technology has become one of the chemical oxidation technologies widely recognized in the field of pollution remediation, but the traditional homogeneous iron-activated persulfate oxidation technology has a small applicable pH range, is easy to produce a large amount of iron sludge and is greatly affected by environmental conditions, thereby leading to a decrease in degradation efficiency and limiting its application in actual pollution site remediation. It is urgent to provide a new method for remediating chlorinated hydrocarbon pollution. SUMMARY

[0004] In order to develop a method for remediating chlorinated hydrocarbon pollution, the present application provides a method for remediating chlorinated hydrocarbon pollution, a chlorinated hydrocarbon pollution remediation agent and application. The method of the present application significantly reduces the concentration of chlorinated hydrocarbon pollutants in the soil and groundwater of the chlorinated hydrocarbon pollution site, and significantly reduces the concentration of chloroform, dichloromethane, 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene and trichloroethylene.

[0005] The present application provides a method for remediating chlorinated hydrocarbon pollution, comprising the following steps: Setting injection points on the chlorinated hydrocarbon pollution site; Preparing a sodium persulfate solution with a mass concentration of 7.5% to 15%, and a mixed solution of ferrous sulfate with a mass concentration of 1.6% to 3.2% and sodium pyrophosphate with a mass concentration of 1.25% to 2.5%, i.e. a ferric pyrophosphate mixed solution; Drilling according to the set injection points, drilling to the pollution depth of the chlorinated hydrocarbon pollution site, stopping drilling, and uniformly spraying the sodium persulfate solution from deep to shallow; then re-drilling to the pollution depth of the chlorinated hydrocarbon pollution site, uniformly spraying the ferric pyrophosphate mixed solution from deep to shallow, and performing chemical oxidation remediation; After 7 to 14 days of chemical oxidation remediation, spraying 5L to 10L of emulsified vegetable oil at the injection points, and naturally remediating for 30 to 35 days at 25°C to 30°C.

[0006] The present application significantly reduces the concentration of chlorinated hydrocarbon pollutants, such as chloroform, dichloromethane, 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene and trichloroethylene, by respectively spraying a mixed solution of sodium persulfate solution and ferric pyrophosphate solution with a mass concentration of 7.5% to 15% at the pollution depth of the chlorinated hydrocarbon contaminated site.

[0007] It should be noted that the pollution depth refers to the deepest part of the pollution range. The soil samples at different depths of the contaminated site are investigated, and then the concentration of pollutants in the soil samples is detected and analyzed. If the concentration exceeds the standard, it is determined as pollution. The pollution below this depth is generally not over standard or does not exist.

[0008] Further, the injection pressure when spraying the sodium persulfate solution or the ferric pyrophosphate mixed solution is 25 MPa to 30 MPa, and the spraying flow rate is 100 L / min to 150 L / min.

[0009] Further, the spraying of the sodium persulfate solution or the ferric pyrophosphate mixed solution is realized by the high-pressure rotary spraying drill rod of the double-tube high-pressure rotary spraying pile; The spraying process is: spraying while rotating and lifting the high-pressure rotary spraying drill rod, the rotation speed of the high-pressure rotary spraying drill rod is 10 r / min to 20 r / min, and the lifting speed of the high-pressure rotary spraying drill rod is 100 cm / min to 200 cm / min.

[0010] Further, the injection pressure when spraying the sodium persulfate solution is 25 MPa, the spraying flow rate is 150 L / min, the high-pressure rotary spraying drill rod is rotated and lifted while spraying, the rotation speed of the high-pressure rotary spraying drill rod is 10 r / min, and the lifting speed of the high-pressure rotary spraying drill rod is 100 cm / min.

[0011] Further, the injection pressure when spraying the ferric pyrophosphate mixed solution is 30 MPa, the spraying flow rate is 100 L / min, the high-pressure rotary spraying drill rod is rotated and lifted while spraying, the rotation speed of the high-pressure rotary spraying drill rod is 10 r / min, and the lifting speed of the high-pressure rotary spraying drill rod is 100 cm / min.

[0012] Further, the chemical oxidation repair is 14 days.

[0013] Further, 10 L of emulsified vegetable oil is sprayed at the injection point.

[0014] Further, the injection points are set on the chlorinated hydrocarbon contaminated site as follows: 20 to 25 injection wells are set every 96 m 2 ~ 100 m 2 The interval between adjacent two injection wells is 1.7 m to 1.732 m.

[0015] The application further provides a chlorinated hydrocarbon pollution remediation agent, which is composed of a sodium persulfate solution with a mass concentration of 7.5-15%, a ferrous sulfate solution with a mass concentration of 1.6-3.2% and a sodium pyrophosphate solution with a mass concentration of 1.25-2.5%. The spraying path of the sodium persulfate solution with a mass concentration of 7.5-15% is performed according to the steps in claim 1; and the spraying path of the mixture of the ferrous sulfate solution with a mass concentration of 1.6-3.2% and the sodium pyrophosphate solution with a mass concentration of 1.25-2.5% is the same as that of the sodium persulfate solution.

[0016] The application further provides application of the chlorinated hydrocarbon pollution remediation agent in chlorinated hydrocarbon pollution soil and / or chlorinated hydrocarbon pollution groundwater remediation. 2 ~100m 2 20-25 injection wells are arranged, and the interval between two adjacent injection wells is 1.7-1.732 m. A drill of the double-tube high-pressure rotary jet pile is used to drill a hole according to the arranged injection well, and the drill is lowered to a pollution depth of 10-11.1 m of the site; the sodium persulfate solution is sprayed through a medicine spraying pump of the double-tube high-pressure rotary jet pile, the high-pressure rotary jet drill rod of the double-tube high-pressure rotary jet pile is rotated and lifted while spraying, the injection pressure is 25-30 MPa when the sodium persulfate solution or the mixed solution of ferrous pyrophosphate is sprayed, the medicine spraying flow rate is 100-150 L / min, the rotary speed of the high-pressure rotary jet drill rod is 10-20 r / min, and the lifting speed of the high-pressure rotary jet drill rod is 100-200 cm / min; then the mixture of the ferrous sulfate solution with a mass concentration of 1.6-3.2% and the sodium pyrophosphate solution with a mass concentration of 1.25-2.5% is sprayed in the same way. After the spraying is completed, chemical oxidation remediation is performed for 7-14 days, 5-10 L of emulsified vegetable oil is sprayed at the injection point, and natural remediation is performed at 25-30℃ for 30-35 days.

[0017] Compared with the prior art, the application has the following beneficial effects: The method for repairing chlorinated hydrocarbon contaminated sites provided by the application uses chemical oxidation combined with indigenous microorganism stimulation to repair chlorinated hydrocarbon contaminants. In Example 1, in most deep level soil, various chlorinated hydrocarbons are even reduced to below the detection limit. Even in the deep level soil of 8m-10m and 10m-12m, the degradation rates of chloroform concentration are 85% and 74% respectively. The concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene in groundwater are reduced from 86100 μg / L, 9060 μg / L, 6170 μg / L, 810 μg / L and 2445 μg / L to 19.9 μg / L, 447 μg / L, 3.8 μg / L, 2.3 μg / L and 11.0 μg / L respectively. In Example 2, in most deep level soil, various chlorinated hydrocarbons are even reduced to below the detection limit. Even in the deep level soil of 8m-10m and 10m-12m, the chloroform concentration after repair is still relatively high, but is reduced from 8380 μg / kg and 10000 μg / kg before repair to 3310 μg / kg and 2100 μg / kg respectively, and the degradation rates are 60% and 79% respectively. The concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene in groundwater at the P14 injection well point are reduced from 72300 μg / L, 6310 μg / L, 13900 μg / L, 1900 μg / L and 1020 μg / L to 228 μg / L, 206 μg / L, 75.7 μg / L, 79.6 μg / L and 385 μg / L respectively. In Example 3, in most deep level soil, various chlorinated hydrocarbons are even reduced to below the detection limit. Even in the soil of 6m-8m and 8m-10m, the chloroform concentration after repair is still relatively high, but is reduced from 18300 μg / kg and 28300 μg / kg before repair to 2790 μg / kg and 261 μg / kg respectively, and the degradation rates are 85% and 99% respectively. The concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene in groundwater at the P24 injection well point are reduced from 17600 μg / L, 4480 μg / L, 2220 μg / L, 971 μg / L and 1220 μg / L to 313 μg / L, 330 μg / L, 971 μg / L, 196 μg / L and 625 μg / L respectively.

[0018] It can be seen that the method of the present application achieves a very significant effect on the remediation of chlorinated hydrocarbon pollution. The method of the present application has a significantly expanded pH range, and due to pyrophosphate complexation, the amount of iron sludge produced is small. Compared with the current mainstream iron-activated persulfate oxidation technology, the pyrophosphate chelated iron-activated persulfate technology greatly improves the degradation rate of TCE in groundwater or soil. Pyrophosphate can also provide an effective phosphorus source for indigenous microorganisms, and with the addition of emulsified vegetable oil, the dechlorination and degradation activity of indigenous microorganisms can be greatly enhanced, so that TCE is completely degraded into non-toxic byproducts such as carbon dioxide and water. Compared with the current prior art, the long-term effect is improved, and it is more helpful for sustainable and collaborative management of soil and water.

[0019] The method for remediation of chlorinated hydrocarbon contaminated sites provided by the present application can greatly reduce the use amount of persulfate and iron, reduce secondary pollution, realize efficient and stable degradation of various chlorinated hydrocarbons through chemical oxidation, and improve the degradation efficiency of indigenous microorganisms. Compared with single microbial degradation technology, the method is more efficient, improves the remediation efficiency, and reduces the remediation period. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A high-pressure jet grouting injection point layout diagram for the contaminated site to be remediated according to the present application; In the figure, P4, P5, P10 and P11 represent injection wells in Comparative Example 1; P1-P3 and P6-P9 represent injection wells in Example 1; P12-P21 represent injection wells in Example 2; and P22-P29 represent injection wells in Example 3. DETAILED DESCRIPTION

[0022] The specific embodiments of the present application will be described in detail below, but it should be understood that the protection scope of the present application is not limited by the specific embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application. The experimental methods described in the embodiments of the present application are conventional methods, and the materials, reagents, etc. used in the following examples are commercially available unless otherwise specified.

[0023] The drilling and agent spraying tool of the present application adopts double-tube high-pressure rotary jet pile (Hengzhu Foundation), comprising a drilling machine, an air compression pump, a high-pressure water pump, a pesticide spraying pump, a plurality of pesticide solution storage tanks, a high-pressure rotary jet drill rod and an intelligent control system.

[0024] The present application takes a chlorinated hydrocarbon contaminated site in Taizhou, Jiangsu as a test site, and according to the field test, it is determined that the influence radius of high-pressure rotary jet injection agent is about 1m, and 25 chemical oxidation reagent high-pressure rotary jet injection wells and 4 control observation wells (also known as injection wells) are arranged in the chlorinated hydrocarbon contaminated area (about 96m 2 ) in a regular hexagonal arrangement. The injection wells or observation wells are located in the center of the regular hexagon. The present application forms a plurality of circles by connecting the vertices of the hexagon, and each circle represents a regular hexagon. The spacing between two adjacent injection wells is 1.732m, and the arrangement is as shown in Figure 1 The injection depth is 10.6m, which is the depth of chlorinated hydrocarbon pollution. The 25 chemical oxidation reagent high-pressure rotary jet injection wells are respectively marked as P1, P2, P3, P6, P7, P8, P9, P12, P13, P14, P15, P16, P17, P18, P19, P20, P21, P22, P23, P24, P25, P26, P27, P28 and P29; and the 4 control observation wells are respectively marked as P4, P5, P10 and P11.

[0025] The present application provides a method for repairing chlorinated hydrocarbon pollution, which comprises the following steps: Preparation of a sodium persulfate solution with a mass concentration of 7.5% to 15%, and a mixed solution of ferrous sulfate with a mass concentration of 1.6% to 3.2% and sodium pyrophosphate with a mass concentration of 1.25% to 2.5%, i.e. a ferric pyrophosphate mixed solution; Drilling is performed according to the set injection points, and the drill is lowered to the pollution depth of the chlorinated hydrocarbon contaminated site, and drilling is stopped. The sodium persulfate solution is uniformly sprayed from deep to shallow; then the drill is lowered again to the pollution depth of the chlorinated hydrocarbon contaminated site, and the ferric pyrophosphate mixed solution is uniformly sprayed from deep to shallow, and chemical oxidation repair is performed; After 7 to 14 days of chemical oxidation repair, 5L to 10L of emulsified vegetable oil is sprayed into the injection point at 25℃ to 30℃, and natural repair is performed for 30 to 35 days.

[0026] The two agents are sprayed from the chlorinated hydrocarbon pollution depth of the chlorinated hydrocarbon contaminated site, i.e. from a depth of 10.6m from the ground, and the sodium persulfate solution and the ferric pyrophosphate mixed solution are sprayed in turn and overlap, and the two agents completely overlap, ensuring the iron activation effect.

[0027] Example 1: A method for repairing chlorinated hydrocarbon pollution.

[0028] Example 1 sets up P1-P3 and P6-P9 injection well point, using the following method for processing, select the middle injection well point P2 as representative, detection of the repair effect on chlorinated hydrocarbon pollution.

[0029] Dissolve 75 kg of sodium persulfate in 1000 L of water, stir evenly with a blender, prepare a sodium persulfate solution with a mass concentration of 7.5%. Dissolve 16 kg of ferrous sulfate and 12.5 kg of sodium pyrophosphate in 1000 L of water, stir evenly with a blender, prepare a mixed solution of ferrous sulfate with a mass concentration of 1.6% and sodium pyrophosphate with a mass concentration of 1.25%, which is referred to as a ferric pyrophosphate mixed solution. Place the sodium persulfate solution and the ferric pyrophosphate mixed solution in two reagent solution storage tanks, respectively. The two reagent storage tanks are connected to the reagent injection pump through pipes (with on-off valves). At the injection well point, drill a hole using a double-tube high-pressure rotary jet pile, start the drilling machine, air compression pump and high-pressure water pump, and drill to a depth of 10.6 m in the contaminated area, and stop drilling. Start the reagent injection pump to inject the sodium persulfate solution, with an injection pressure of 25 MPa and a reagent injection flow rate of 150 L / min, rotate and lift the high-pressure rotary jet drill rod while injecting the reagent, with a rotary speed of 10 r / min and a lifting speed of 100 cm / min, and uniformly inject the sodium persulfate solution into the contaminated area. After the high-pressure rotary jet drill rod leaves the injection well, close the valve on the pipe connecting the sodium persulfate solution storage tank and open the valve on the pipe connecting the ferric pyrophosphate solution storage tank. At this time, the ferric pyrophosphate solution storage tank is connected to the reagent injection pump. Then, drill the high-pressure rotary jet drill rod to a depth of 10.6 m in the contaminated area, start the reagent injection pump to inject the ferric pyrophosphate mixed solution, with an injection pressure of 30 MPa and a reagent injection flow rate of 100 L / min, rotate and lift the high-pressure rotary jet drill rod while injecting the reagent, with a rotary speed of 10 r / min and a lifting speed of 100 cm / min, and uniformly inject the ferric pyrophosphate mixed solution into the contaminated area. Remove the double-tube high-pressure rotary jet pile, and then perform chemical oxidation repair. After 7 days of chemical oxidation repair, inject 5 L of emulsified vegetable oil into the injection well point using a double-tube high-pressure rotary jet pile, at an ambient temperature of 25°C, and naturally repair for 30 days. Take soil and groundwater samples from different depths of the P2 injection well to determine the concentration of chlorinated hydrocarbons. The soil samples from different depths of the P2 injection well are denoted as P2-1 for the 2.0 m-4.0 m depth, P2-2 for the 4.0 m-6.0 m depth, P2-3 for the 6.0 m-8.0 m depth, P2-4 for the 8.0 m-10.0 m depth, and P2-5 for the 10.0 m-12.0 m depth. The groundwater sample from the P2 injection well is denoted as P2.

[0030] The method for detecting the concentration of chlorinated hydrocarbon substances in the soil of the test site: the soil at different depths was collected by a Geoprobe sampling device, and the concentration of chlorinated hydrocarbons in the soil was detected according to HJ 741-2015 Soil and Sediment Analysis of Volatile Organic Compounds.

[0031] The method for detecting the concentration of chlorinated hydrocarbon substances in the groundwater of the test site: a Bell tube was used to collect groundwater samples, and the concentration of chlorinated hydrocarbons in the groundwater was detected according to HJ 810-2016 Determination of Water Quality Volatile Organic Compounds Headspace / Gas Chromatography-Mass Spectrometry.

[0032] As shown in Table 1, the soil at the P2 injection well site was contaminated by multiple chlorinated hydrocarbons. The concentration of chloroform in the soil was as high as 9500 μg / kg-27000 μg / kg, and the concentration of dichloromethane was as high as 6840 μg / kg-51350 μg / kg. The concentrations of 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene and trichloroethylene were also relatively high, and were 524 μg / kg-1420 μg / kg, 105 μg / kg-1780 μg / kg, 3520 μg / kg-10700 μg / kg and 194 μg / kg-8230 μg / kg, respectively.

[0033] After the method of Example 1 was used for remediation, the concentrations of all chlorinated hydrocarbons showed a significant decreasing trend, and the results are shown in Table 3. In most of the soil at different depths, the concentrations of multiple chlorinated hydrocarbons were even reduced to below the detection limit. Even in the deep soil at 8 m-10 m and 10 m-12 m, the concentration of chloroform was relatively high after remediation, but it was reduced from 18800 μg / kg and 16900 μg / kg before remediation to 2790 μg / kg and 4340 μg / kg, respectively, with degradation rates of 85% and 74%, respectively. With the increase of the activity of indigenous microorganisms, the concentration of chlorinated hydrocarbons in the soil will continue to decrease.

[0034] As shown in Table 2, the groundwater at the P2 injection well site before remediation was also contaminated by multiple chlorinated hydrocarbons. The concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene were relatively high, and were 86100 μg / L, 9060 μg / L, 6170 μg / L, 810 μg / L and 2445 μg / L, respectively. After the method of Example 1 was used for remediation, the concentrations of all chlorinated hydrocarbons showed a significant decrease, as shown in Table 4 for P2. The concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene were relatively high, and were reduced to 19.9 μg / L, 447 μg / L, 3.8 μg / L, 2.3 μg / L and 11.0 μg / L, respectively.

[0035] Example 2: A method for repairing chlorinated hydrocarbon pollution.

[0036] Example 2 sets up P12-P21 injection well point, using the following method for treatment, select the middle injection well point P14 as representative, detection of chlorinated hydrocarbon pollution repair effect.

[0037] Dissolve 150 kg of sodium persulfate in 1000 L of water, stir evenly with a blender, prepare a sodium persulfate solution with a mass concentration of 15%. Dissolve 32 kg of ferrous sulfate and 50 kg of sodium pyrophosphate in 1000 L of water, stir evenly with a blender, prepare a mixed solution of ferrous sulfate with a mass concentration of 3.2% and sodium pyrophosphate with a mass concentration of 2.5%, which is referred to as a ferric pyrophosphate mixed solution. The sodium persulfate solution and the ferric pyrophosphate mixed solution are placed in two medicament solution storage tanks respectively. The two medicament storage tanks are connected to the injection pump through a pipeline (with a switch valve installed). At the injection well point, a double-tube high-pressure rotary jet pile is used for drilling, the drilling machine, air compression pump and high-pressure water pump are started, the drill is lowered to a pollution depth of 10.6 m, and drilling is stopped. The injection pump is started to spray the sodium persulfate solution, the injection pressure is 30 MPa, the spraying flow rate is 100 L / min, the high-pressure rotary jet drill rod is rotated and lifted while spraying, the rotary speed of the high-pressure rotary jet drill rod is 20 r / min, the lifting speed of the high-pressure rotary jet drill rod is 200 cm / min, and the sodium persulfate solution is uniformly sprayed into the contaminated area. After the high-pressure rotary jet drill rod leaves the injection well, the valve on the pipeline connecting the sodium persulfate solution storage tank is closed, and the valve on the pipeline connecting the ferric pyrophosphate solution storage tank is opened. At this time, the ferric pyrophosphate solution storage tank is connected to the injection pump. Subsequently, the high-pressure rotary jet drill rod is lowered to a pollution depth of 10.6 m, the injection pump is started to spray the ferric pyrophosphate mixed solution, the injection pressure is 30 MPa, the spraying flow rate is 100 L / min, the high-pressure rotary jet drill rod is rotated and lifted while spraying, the rotary speed of the high-pressure rotary jet drill rod is 20 r / min, the lifting speed of the high-pressure rotary jet drill rod is 200 cm / min, and the ferric pyrophosphate mixed solution is uniformly sprayed into the contaminated area. Then chemical oxidation repair is carried out, after 14 days of chemical oxidation repair, 5 L of emulsified vegetable oil is sprayed into the above injection well at the injection point using a double-tube high-pressure rotary jet pile, and natural repair is carried out at an environmental temperature of 30°C for 30 days. Soil and groundwater samples at different depths of the P14 injection well are taken to determine the concentration of chlorinated hydrocarbons, the 2.0 m-4.0 m depth soil point of the P14 injection well is denoted as P14-1, the 4.0 m-6.0 m depth soil point is denoted as P14-2, the 6.0 m-8.0 m depth soil point is denoted as P14-3, the 8.0 m-10.0 m depth soil point is denoted as P14-4, and the 10.0 m-12.0 m depth soil point is denoted as P14-5. The groundwater sample of the P14 injection well is directly denoted as P14.

[0038] The method for detecting the concentration of chlorinated hydrocarbon substances in the soil of the test site is as follows: the soil at different depths is collected by a Geoprobe sampling device, and the concentration of chlorinated hydrocarbon in the soil is detected according to HJ 741-2015 Soil and Sediment Analysis of Volatile Organic Compounds.

[0039] The method for detecting the concentration of chlorinated hydrocarbon substances in the groundwater of the test site is as follows: a Bell tube is used to collect groundwater samples, and the concentration of chlorinated hydrocarbon in the groundwater is detected according to HJ 810-2016 Determination of Water Quality Volatile Organic Compounds Headspace / Gas Chromatography-Mass Spectrometry.

[0040] As shown in Table 1, the soil in the P14 injection well is contaminated by multiple chlorinated hydrocarbons, and the concentrations of chloroform and dichloromethane are the highest, reaching 4960 μg / kg-72900 μg / kg and 11700 μg / kg-36100 μg / kg, respectively. The concentrations of 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene and trichloroethylene are also relatively high, reaching 620 μg / kg-4170 μg / kg, 52.3 μg / kg-892 μg / kg, 1110 μg / kg-12600 μg / kg and 79.2 μg / kg-8010 μg / kg, respectively.

[0041] After the method of the present embodiment, the concentrations of all chlorinated hydrocarbons are significantly reduced after the combined chemical oxidation and indigenous microorganism stimulation repair, and the results are shown in Table 3. In most of the soil at different depths, the concentrations of multiple chlorinated hydrocarbons are even reduced to below the detection limit. Even in the soil at depths of 8m-10m and 10m-12m, the concentrations of chloroform after repair are still relatively high, but they are reduced from 8380 μg / kg and 10000 μg / kg before repair to 3310 μg / kg and 2100 μg / kg, respectively, with degradation rates of 60% and 79%, respectively. With the increase of the activity of indigenous microorganisms, the concentrations of chlorinated hydrocarbons in the soil will continue to decrease.

[0042] As shown in Table 2, the groundwater at the P14 injection well site before repair is also contaminated by multiple chlorinated hydrocarbons, and the concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene are relatively high, reaching 72300 μg / L, 6310 μg / L, 13900 μg / L, 1900 μg / L and 1020 μg / L, respectively. After the method of the present embodiment 2 is used for repair, the concentrations of all chlorinated hydrocarbons are significantly reduced (Table 4 TW2), and the concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene are relatively high, being reduced to 228 μg / L, 206 μg / L, 75.7 μg / L, 79.6 μg / L and 385 μg / L, respectively.

[0043] Example 3: A method for repairing chlorinated hydrocarbon pollution.

[0044] Example 3 sets up P22-P29 injection well point, using the following method for processing, select the middle of the injection well point P24 as representative, detection of the repair effect of chlorinated hydrocarbon pollution.

[0045] Dissolve 75 kg of sodium persulfate in 1000 L of water, stir evenly with a blender, prepare a sodium persulfate solution with a mass concentration of 7.5%. Dissolve 16 kg of ferrous sulfate and 12.5 kg of sodium pyrophosphate in 1000 L of water, stir evenly with a blender, prepare a mixed solution of ferrous sulfate with a mass concentration of 1.6% and sodium pyrophosphate with a mass concentration of 1.25%, which is referred to as a ferric pyrophosphate mixed solution. Place the sodium persulfate solution and the ferric pyrophosphate mixed solution in two medicament solution storage tanks, respectively. The two medicament storage tanks are connected to the spray pump through a pipeline (with a switch valve installed). At the injection well point, drill a hole using a double-tube high-pressure rotary jet pile, start the drilling machine, air compression pump and high-pressure water pump, lower the drill to a pollution depth of 10.6 m, and stop drilling. Start the spray pump to spray the sodium persulfate solution, with an injection pressure of 25 MPa and a spray flow rate of 150 L / min, rotate and raise the high-pressure rotary jet drill rod while spraying, with a rotary speed of 10 r / min and a raising speed of 100 cm / min, and uniformly spray the sodium persulfate solution into the contaminated area. After the high-pressure rotary jet drill rod leaves the injection well, close the valve on the pipeline connecting the sodium persulfate solution storage tank and open the valve on the pipeline connecting the ferric pyrophosphate solution storage tank. At this time, the ferric pyrophosphate solution storage tank is connected to the spray pump. Then, lower the high-pressure rotary jet drill rod to a pollution depth of 10.6 m, start the spray pump to spray the ferric pyrophosphate mixed solution, with an injection pressure of 30 MPa and a spray flow rate of 100 L / min, rotate and raise the high-pressure rotary jet drill rod while spraying, with a rotary speed of 10 r / min and a raising speed of 100 cm / min, and uniformly spray the ferric pyrophosphate mixed solution into the contaminated area. Remove the double-tube high-pressure rotary jet pile, then perform chemical oxidation repair, and after 14 days of chemical oxidation repair, spray 10 L of emulsified vegetable oil into the injection well point using a gas-liquid double-tube high-pressure rotary jet pile, at an environmental temperature of 25°C, and naturally repair for 30 days. Take soil and groundwater samples at different depths of the P24 injection well to determine the concentration of chlorinated hydrocarbons, with the 2.0 m-4.0 m depth soil point of the P24 injection well being referred to as P24-1, the 4.0 m-6.0 m depth soil point being referred to as P24-2, the 6.0 m-8.0 m depth soil point being referred to as P24-3, the 8.0 m-10.0 m depth soil point being referred to as P24-4, and the 10.0 m-12.0 m depth soil point being referred to as P24-5. The groundwater sample of the P24 injection well is directly referred to as P24.

[0046] The method for detecting the concentration of chlorinated hydrocarbon substances in the soil of the test site is as follows: the soil at different depths is collected by a Geoprobe sampling device, and the concentration of chlorinated hydrocarbon in the soil is detected according to HJ 741-2015 Soil and Sediment Analysis of Volatile Organic Compounds.

[0047] The method for detecting the concentration of chlorinated hydrocarbon substances in the groundwater of the test site is as follows: a Bell tube is used to collect groundwater samples, and the concentration of chlorinated hydrocarbon in the groundwater is detected according to HJ 810-2016 Determination of Water Quality Volatile Organic Compounds Headspace / Gas Chromatography-Mass Spectrometry.

[0048] As shown in Table 1, the soil in the P24 injection well of the test site is contaminated by multiple chlorinated hydrocarbons. The concentration of chloroform in the soil is as high as 1980 μg / kg-153000 μg / kg, and the concentration of dichloromethane is as high as 6470 μg / kg-17500 μg / kg. The concentrations of 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene and trichloroethylene are also high, and they are 1120 μg / kg-4630 μg / kg, 36.8 μg / kg-2130 μg / kg, 1540 μg / kg-15400 μg / kg and 1640 μg / kg-2460 μg / kg, respectively.

[0049] After the method of this embodiment, the concentration of all chlorinated hydrocarbons is significantly reduced after the combined chemical oxidation and indigenous microorganism stimulation repair, as shown in Table 3. In most of the soil at different depths, the concentrations of multiple chlorinated hydrocarbons are even reduced to below the detection limit. Even in the soil at a depth of 6m-8m and 8m-10m, the concentration of chloroform after repair is still relatively high, but it is reduced from 18300 μg / kg and 28300 μg / kg before repair to 2790 μg / kg and 261 μg / kg, respectively, with a degradation rate of 85% and 99%, respectively. With the increase of the activity of indigenous microorganisms, the concentration of chlorinated hydrocarbons in the soil will continue to decrease.

[0050] As shown in Table 2, the groundwater at the P24 injection well site before repair also shows multiple chlorinated hydrocarbon contamination, among which the concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene are relatively high, reaching 17600 μg / L, 4480 μg / L, 2220 μg / L, 971 μg / L and 1220 μg / L, respectively. After the combined chemical oxidation and indigenous microorganism stimulation repair, the concentration of all chlorinated hydrocarbons is significantly reduced (Table 4 TW2), and the concentrations of chloroform, cis-1,2-dichloroethylene, dichloromethane, 1,1,2-trichloroethane and trichloroethylene are relatively high, which are reduced to 313 μg / L, 330 μg / L, 971 μg / L, 196 μg / L and 625 μg / L, respectively.

[0051] Comparative Example 1: Comparative Example 1 sets P4, P5, P10 and P11 injection well points as a control group, at ambient temperature 25℃, natural repair for 37 days. Select the middle injection well point P5 injection well as a representative, detect the repair effect of chlorinated hydrocarbon pollution.

[0052] Respectively take the soil and groundwater samples of different depths of P5 injection well to determine the concentration of chlorinated hydrocarbons, P5 injection well 2.0 m-4.0 m depth point is recorded as P5-1, 4.0 m-6.0 m depth point is recorded as P5-2, 6.0 m-8.0 m depth point is recorded as P5-3, 8.0 m-10.0 m depth point is recorded as P5-4, 10.0 m-12.0 m depth point is recorded as P5-5.

[0053] As can be seen from Table 1 and Table 3, the concentration of each chlorinated hydrocarbon in the soil of the site does not show a significant decrease. As can be seen from Table 2 and Table 4, the concentration of each chlorinated hydrocarbon in the groundwater also does not produce a significant change. It can be seen that the above chemical oxidation combined with indigenous microorganism stimulation repair of different treatment groups shows good repair effect.

[0054] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic inventive concept.

[0055] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method for remediating chlorinated hydrocarbon contamination, characterized by, It comprises the following steps: Setting injection points on the chlorinated hydrocarbon contaminated site; Preparing a sodium persulfate solution with a mass concentration of 7.5%-15%, and a mixed solution of ferrous sulfate with a mass concentration of 1.6%-3.2% and sodium pyrophosphate with a mass concentration of 1.25%-2.5%, i.e. a ferric pyrophosphate mixed solution; Drilling according to the set injection points, drilling to the pollution depth of the chlorinated hydrocarbon contaminated site, stopping drilling, and uniformly spraying the sodium persulfate solution from deep to shallow; Then re-drilling to the pollution depth of the chlorinated hydrocarbon contaminated site, uniformly spraying the ferric pyrophosphate mixed solution from deep to shallow, and performing chemical oxidation remediation; After 7-14 days of chemical oxidation remediation, spraying 5-10 L of emulsified vegetable oil at the injection points, and naturally remediating for 30-35 days at 25-30°C.

2. The method of remediating chlorinated hydrocarbon contamination according to claim 1, wherein, The injection pressure when spraying the sodium persulfate solution or the ferric pyrophosphate mixed solution is 25-30 MPa, and the spraying flow rate is 100-150 L / min.

3. The method of remediating chlorinated hydrocarbon contamination according to claim 2, wherein, The sodium persulfate solution or the ferric pyrophosphate mixed solution is sprayed by means of a high-pressure rotary jet drill rod relying on a double-tube high-pressure rotary jet pile; The spraying process is: spraying while rotating and lifting the high-pressure rotary jet drill rod, the rotation speed of the high-pressure rotary jet drill rod is 10-20 r / min, and the lifting speed of the high-pressure rotary jet drill rod is 100-200 cm / min.

4. The method of remediating chlorinated hydrocarbon contamination according to claim 3, wherein, When spraying the sodium persulfate solution, the injection pressure is 25 MPa, the spraying flow rate is 150 L / min, the high-pressure rotary jet drill rod is rotated and lifted while spraying, the rotation speed of the high-pressure rotary jet drill rod is 10 r / min, and the lifting speed of the high-pressure rotary jet drill rod is 100 cm / min.

5. The method of remediating chlorinated hydrocarbon contamination according to claim 4, wherein, When spraying the ferric pyrophosphate mixed solution, the injection pressure is 30 MPa, the spraying flow rate is 100 L / min, the high-pressure rotary jet drill rod is rotated and lifted while spraying, the rotation speed of the high-pressure rotary jet drill rod is 10 r / min, and the lifting speed of the high-pressure rotary jet drill rod is 100 cm / min.

6. The method of remediating chlorinated hydrocarbon contamination according to claim 1, wherein, Chemical oxidation remediation is performed for 14 days.

7. The method of remediating chlorinated hydrocarbon contamination according to claim 1, wherein, 10 L of emulsified vegetable oil is sprayed at the injection points.

8. The method of remediating chlorinated hydrocarbon contamination according to claim 1, wherein, Injection points are set on the chlorinated hydrocarbon contaminated site: every 96 m 2 ~ 100 m 2 20~25 injection wells are set, and the interval between two adjacent injection wells is 1.7 m ~ 1.732 m.

9. A chlorinated hydrocarbon contamination remediation agent characterized in that, It is composed of a sodium persulfate solution with a mass concentration of 7.5%-15% and a mixed solution of ferrous sulfate with a mass concentration of 1.6%-3.2% and sodium pyrophosphate with a mass concentration of 1.25%-2.5%. The spraying path of the sodium persulfate solution with a mass concentration of 7.5%-15% is performed according to the steps in claim 1, and the spraying path of the mixed solution of ferrous sulfate with a mass concentration of 1.6%-3.2% and sodium pyrophosphate with a mass concentration of 1.25%-2.5% is the same as that of the sodium persulfate solution.

10. Use of a chlorinated hydrocarbon-contaminated soil and / or groundwater remediation agent according to claim 9 for the remediation of chlorinated hydrocarbon-contaminated soil and / or groundwater, characterized in that Injection wells are set up at chlorinated hydrocarbon contaminated sites, every 96m 2 ~ 100m 2 20~25 injection wells are set up, and the interval between two adjacent injection wells is 1.7m ~ 1.732m; The drill of the double-tube high-pressure jet grouting pile is used to drill according to the set injection well, and the drill is lowered to the pollution depth of 10 m to 11.1 m of the site, the sodium sulfate solution is sprayed through the medicine spraying pump of the double-tube high-pressure jet grouting pile, the high-pressure jet grouting drill rod of the double-tube high-pressure jet grouting pile is rotated and lifted while spraying, the injection pressure when spraying the sodium sulfate solution or the mixed solution of ferric pyrophosphate is 25 MPa to 30 MPa, the medicine spraying flow rate is 100 L / min to 150 L / min, the rotation speed of the high-pressure jet grouting drill rod is 10 r / min to 20 r / min, and the lifting speed of the high-pressure jet grouting drill rod is 100 cm / min to 200 cm / min; then the mixed solution of ferrous sulfate with a mass concentration of 1.6% to 3.2% and sodium pyrophosphate with a mass concentration of 1.25% to 2.5% is sprayed in the same way; After spraying, the chemical oxidation repair is carried out for 7 days to 14 days, 5 L to 10 L of emulsified vegetable oil is sprayed at the injection point, and natural repair is carried out at 25 ℃ to 30 ℃ for 30 days to 35 days.

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