CN207472845U - The experimental provision of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources is repaired based on Zero-valent Iron-PRB reduction - Google Patents

Abstract

The experimental provision of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources is repaired based on Zero-valent Iron PRB reduction.The experimental provision includes sequentially connected water supply installation, cylinder simulator, sampling apparatus and waste collecting device.For pollution caused by saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources, the solubilised state DNAPL ingredients that the application flows through wall by installing Zero-valent Iron PRB pair near pollution sources carry out deoxidization, degradation, and saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources are repaired.Simulated experiment shows, Zero-valent Iron PRB is installed near pollution sources can strengthen the rate of dissolution of DNAPL pollution sources, shorten existence time of the saturated aqueous layer DNAPL pollution sources in underground environment, the in-situ chemical for DNAPL pollution sources restores repairing research and provides mentality of designing and critical technical parameter.

Description

Saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources are repaired based on Zero-valent Iron-PRB reduction Experimental provision

Technical field

This application involves soil and groundwater pollution amelioration fields, particularly relate to a kind of based on Zero-valent Iron-PRB reduction reparations The experimental provision of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources.

Background technology

Dense non-aqueous phase liquids (Dense non-aqueous phase liquid, DNAPL) are as the important raw material of industry It is widely used in agricultural, fuel, field of medicaments, leakage and row easily occurs during production, transport, storage and use It puts, DNAPL is caused largely to enter underground environment.This part enter underground environment DNAPL can under the effect of gravity constantly to It is migrated in soil and groundwater, accumulates forming DNAPL ponds in weak permeable or impermeable stratum, so as to slowly constantly to underground ring Border discharges pollutant, forms a kind of persistent pollution sources, and " permanent reparation " is also referred to as to its reparation.The U.S.《State The preferential pollution administration place sequence list of family》It has been shown that, about 60% place there are DNAPL pollutions (McDade et al., 2005).Common DNAPL pollutants include：Chlorinated hydrocarbon, coal tar oils and pesticide pollutant, wherein chlorinated hydrocarbon are dirty Dye object is a kind of substance that recall rate is higher in China's groundwater pollutant, and the chlorinated hydrocarbon DNAPL that this kind of pollution is formed is biological Degradability is low, and pollution depth is even up in the basement rock of underground 60m, makes biological treatment, Pump-and-Treat or excavates the technologies such as burning It is bad to the repairing effect of DNAPL.Research is proved permeable reactive barrier technology (Permeable both at home and abroad at present Reactive Barrier, abridge PRB) long-term in-situ treatment can be carried out to pollutant in soil or underground water pollution plumage, And have the characteristics that it is good in economic efficiency, convenient for management, especially European and American areas has been used widely in the world, but The country because PRB technology repairing efficiencies are relatively long, have no be used alone case (horse is beautiful etc., 2016；Relaxation etc., 2014；Qiu Brocade peace etc. is 2011).

Europe is still in operation at present using earliest PRB, and still has drop to chlorinated hydrocarbon contaminants in underground water Solution acts on.But the mode in this downstream contamination feather tract domain that PRB is mounted remotely to pollution sources, removal is downstream contamination plumage Pollutant in local ground watering has no influence to the persistence of DNAPL pollution sources.This is mainly due to DNAPL contaminated areas The course of dissolution of the opposite underground water of DNAPL is mainly by actual concentrations of the DNAPL in underground water and the theoretic dissolvings of DNAPL The influence of equilibrium concentration, the two concentration difference is bigger, and DNAPL dissolvings are faster.But in practical situations, downstream contamination feather tract domain away from From DNAPL pollution sources farther out, the pollutant reduction removal in downstream contamination plumage is to DNAPL contaminated areas water phase pollutant concentration Influence little, no effect for strengthening the rate of dissolution of the opposite water phases of DNAPL in pollution sources, so as to cause PRB technology reparations During DNAPL polluted underground waters required repair time much larger than other recovery techniques (Berge et al., 2010；Phillips et al., 2010；Gillham et al., 1998).Therefore the rate of dissolution of DNAPL contaminated site DNAPL pollution sources how is improved With quick, thorough removal DNAPL pollutants, become the key point of DNA plerosis PL contaminated site reparations.

The oxidation-reduction potential of Zero-valent Iron be -0.44eV, the DNAPL ingredient deoxidization, degradations that can be dissolved in water phase. But at present about Fe⁰The research of removal DNAPL pollution sources focuses primarily upon nano zero valence iron and its binary load system, not Visual angle is turned into the higher Zero-valent Iron-PRB systems of engineering application value, Zero-valent Iron grain size is smaller, can participate in contaminant degradation The effective ratio area of reaction is bigger, but in practical engineering application and laboratory simulation experiment, powdered Zero-valent Iron and stone Sand proportion differ greatly it is extremely difficult be uniformly mixed, therefore the application in relation to powdered Zero-valent Iron is less.The zeroth order that the application is established Powdered Zero-valent Iron and quartz sand are carried out PRB fillings by iron-PRB systems after mixing in advance using absolute ethyl alcohol, after filling Zero-valent Iron-PRB systems can reach Zero-valent Iron and the equally distributed state of quartz sand so that flow through the polluter of the system Reach maximization with reacting for Zero-valent Iron.The feasibility of DNAPL pollution sources reparations is used for explore Zero-valent Iron-PRB systems, is obtained Zero-valent Iron-PRB repairs the guiding parameter of system engineer application, and the application establishes a kind of Zero-valent Iron-PRB reduction and repaiies for the first time The experimental provision and method of multiple saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources, are only capable of with existing similar one-dimensional and two-dimensional device It is enough in simulation nature migration to compare, the experimental provision that the application is established can not only carry out the laboratory of DNAPL pollution sources Simulation, and reparation of the Zero-valent Iron-PRB walls in DNAPL contaminated areas can be simulated.

Invention content

The technical issues of solution：The application purpose is for above deficiency, provides a kind of Zero-valent Iron-PRB that is based on and restores Repair the experimental provision of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources.The device is by setting different saturated aqueous layer regions Filled media, zone length, saturated aqueous layer conditions and the scientific and reasonable sampling method such as flowing water field, while continuous prison The pollutant component and concentration of different zones are surveyed, persistence of the DNAPL pollution sources in saturated aqueous layer and DNAPL are polluted Remediation efficiency of the source in 7d is analyzed, and the application that systems engineering is repaired for Zero-valent Iron-PRB provides scientific basis, is suitable for The research that saturated aqueous layer DNAPL pollution sources are repaired in Zero-valent Iron-PRB reduction is studied in unidimensional scale.

Technical solution：The experiment dress of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources is repaired based on Zero-valent Iron-PRB reduction It puts, it is characterised in that including：Water supply installation, cylinder simulator and the waste collecting device of pipeline connection successively, the cylinder Simulator is equipped with one group of sampling apparatus；The cylinder simulator includes cylinder, and the both ends of the cylinder are equipped with water inlet end Cylinder lid and water outlet cylinder lid, two cylinders, which cover, is respectively equipped with inlet opening and apopore, on the inlet opening and apopore Be respectively equipped with pneumatic tube, sieve be equipped between cylinder lid and cylinder, be equipped with successively in cylinder the first filter layer, DNAPL contaminated areas, PRB regions, PRB downstream areas and the second filter layer, the corresponding damaged surface in the DNAPL contaminated areas are injected equipped with DNAPL Hole, the PRB regions and the corresponding damaged surface of PRB downstream areas are equipped with one group of top thieff hatch；The sampling apparatus is set on In the thieff hatch of top.

Water-supply-pipe between above-mentioned water supply installation and cylinder simulator is equipped with peristaltic pump.

Outlet pipe between above-mentioned cylinder simulator and waste collecting device is equipped with sampling apparatus.

Above-mentioned DNAPL injection holes are 6.5cm apart from inlet opening；Top thieff hatch apart from inlet opening be followed successively by 8cm, 9.5cm, 11cm, 12.5cm, 15.5cm, 18.5cm, 21.5cm, 24.5cm, 30.5cm, 36.5cm and 66.5cm.

Above-mentioned sampling apparatus is the 20-gauge stainless steel sampling probes with female Luer, and one end of sampling probe is adopted by top Sample hole is inserted perpendicularly into water-bearing layer, and the other end is connect with the check valve with female Luer, and the external tapping of check valve is equipped with micro note Emitter.

The above-mentioned uniform filled media in subregion in cylindrical groove body, including：Quartzy fine sand of the grain size for 60-150 mesh, grain size For sand in the quartz of 35-80 mesh, the quartzy coarse sand that grain size is 4-35 mesh and Zero-valent Iron that grain size is 100-300 mesh；DNAPL Contaminated area and PRB downstream area filled medias are fine sand, and control group and the selection of the filled media in experimental group PRB regions need Ensure that the infiltration coefficient in the region is more than the infiltration coefficient of DNAPL contaminated areas and PRB downstream areas；Experimental group PRB area fillings Medium is Zero-valent Iron and sand mass ratio in quartz is 1:5 homogeneous mixture, control group such as then fill at the sand in quality quarts；Filling The preprocessed features of medium are that the quartz sand respectively uses 0.1M NaOH and 0.1M HNO₃Impregnate 6h, using go from Son is washed to 105 DEG C of baking oven drying after neutrality；The Zero-valent Iron uses 0.1M NaOH and 0.1M HNO respectively₃It is rapid to repeat to wash Three times, it after being washed till neutrality using deionized water, dries and preserves in vacuum freeze drier.

Above-mentioned medium filling method includes the following steps：Cylindricality groove body is placed vertically in filling process, according to the second filtering Layer, PRB downstream areas, PRB regions, DNAPL contaminated areas and the first filter layer are filled successively；PRB downstream areas and The filling of DNAPL contaminated areas and control group PRB Region Mediums uses wet filling mode；Using peristaltic pump by the mould of deoxygenation Intend underground water to inject from apopore, being less than the hollow pipe of 1/2 groove body internal diameter using funnel and internal diameter dries clean and sterilize Fine sand adds in, layering filling, and often filling 3cm disturbances compacting is primary, ensures horizontal plane higher than layer of sand face 2cm- in wet filling process 5cm；The filling of experimental group PRB Region Mediums uses dry-packing mode；ZVI is mixed with middle sand using absolute ethyl alcohol before filling Even, the hollow pipe that 1/2 groove body internal diameter is less than using funnel and internal diameter is filled sand mixture layering in uniformly mixed ZVI- extremely 3cm compactings are often filled once in PRB regions, should make the suffered disturbance of filled media small as possible in compacting process；It is close after filling Apopore is sealed, groove body stands for 24 hours afterwards connect water inlet end cylinder lid with cylindricality groove body vertically, by the cylinder simulator after connection Sealing, horizontal rest is for 24 hours；Water supply installation, cylinder simulator and waste collecting device are sequentially connected, will have been removed using peristaltic pump The simulated groundwater of oxygen is pumped into saturated aqueous layer simulator trial operation 6h, to remove the impurity introduced in filling process.

Pollutant in above-mentioned DNAPL contaminated areas is dyed first using oil red O, and colouring method is：Weigh 0.0005g Oil red O powder is dissolved in 100mL DNAPL liquid, obtains DNAPL dyeing liquids.

The experimental method of above device, the experimental method include the following steps：A. first carry out cylinder simulator with The connection of sampling apparatus；B. Filled Dielectrics and experimental provision trial operation are then carried out；C. using 1mL glass micro syringe from The DNAPL of DNAPL injection holes injection dyeing, charge velocity are 0.5 μ L/min；D. after the completion of injecting, by 5cm long and one end thing The PTFE tube first sealed using silica gel is inserted into respectively in the pneumatic tube of inlet opening and apopore, seals cylinder, and standing makes for 24 hours DNAPL Stable distritations；E. it is sequentially connected water supply installation, cylinder simulator and waste collecting device again, uses peristaltic pump Enter the simulated groundwater of deoxygenation；F. timing acquires sample from thieff hatch, pollutant component and concentration is detected, sample is adopted Collect rate and should be less than simulated groundwater body is pumped into rate 2%.

Advantageous effect：1. the application device can in proportion be carried out indoor according to the hydrological geological conditions in field study area Simulate reparative experiment device, carry out quantitative analysis to the persistence of chlorinated hydrocarbon DNAPL pollution sources, research solubilised state DNAPL into Divide in the upward variation of subsurface flow.Compared to three-dimensional simulation device, which is meeting Zero-valent Iron-PRB reparations On the basis of saturated aqueous layer DNAPL pollution sources, utmostly shorten experimental period, reduce plant area space, reduce simulation Research cost improves single operability, makes laboratory research more operability and economy.2. make compared to whole device For the one dimension experimental apparatus of PRB wall filling regions, DNAPL pollution sources, PRB and PRB downstream areas are pressed in the experimental provision Science ratio (1:4:3) it distributes, it is contemplated that the integrated environment in actual place Zero-valent Iron-PRB reduction repair processes, to PRB Upstream and downstream are simulated.3. innovative is mounted on DNAPL contaminated areas by Zero-valent Iron-PRB, it is opposite to enhance DNAPL The dissolving of water phase, greatly reduces the persistence of DNAPL pollution sources, and scientific basis is provided for practical engineering application.4. the reality The cylinder material of water-bearing layer device is high borosilicate glass in experiment device, with water-wetted surface, avoids the generation preferentially flowed, In addition do not have adsorptivity to DNAPL pollutants.5. Zero-valent Iron is uniformly mixed with middle sand using ethyl alcohol before the application filling Method effectively prevent with middle sand specific gravity difference causing to mix non-uniform phenomenon, while can greatly due to powdered Zero-valent Iron Effectively avoid the Quick Oxidation of Zero-valent Iron.6. in the experimental provision, the nylon screen at water-bearing layer cylinder both ends does not influence original The rate of output water, and can according to the needs of analog study difference filled media, replaced needed for mesh number nylon screen, make filling The selection of layer is not limited by sieve.7. in the experimental provision, PRB filled medias, which can also replace with, has solubilised state DNAPL There are other substances not soluble in water of reduction, oxidation or suction-operated and the mixture of quartz sand.

Description of the drawings

Fig. 1 is the structure diagram of herein described experimental provision；

Fig. 2 is herein described cylinder simulator (a), thieff hatch vertical view (b) and sampling apparatus at the top of cylindricality groove body (c) schematic diagram；

Fig. 3 is the result figure of herein described experiment case study.Fig. 3-a：DNAPL pollution sources variation characterization hole 2# pollutants are dense Spend change curve；Fig. 3-b：The variation of water phase pollutant concentration in 9# holes；Fig. 3-c：The quality of the present invention in application process is kept Perseverance calculates, and by mass balance calculation, characterizes the laboratory feasibility of apparatus of the present invention and method；

In figure：Water supply installation 1, sampling apparatus 3, waste collecting device 4, water inlet end cylinder lid 5, goes out cylinder simulator 2 Water end (W.E.) cylinder lid 6, DNAPL contaminated areas 7, PRB regions 8, PRB downstream areas 9, inlet opening 10, apopore 11, water inlet end pneumatic tube 12nd, water outlet pneumatic tube 13, the first filter layer 14, the second filter layer 15, DNAPL injection holes 16, top thieff hatch 17, water-supply-pipe 18th, peristaltic pump 19, outlet pipe 20, stainless steel sampling needle 21, check valve 22, micro syringe 23, sieve I 24, sieve II 25, Silica gel plug 26.

Specific embodiment

The technical solution that specific embodiment will further illustrate the application with reference to attached drawing and application example.Its object is to The worker for being familiar with technique scheme can understand present context in detail and implement accordingly, it is other to facilitate the application Used in worker.The typical but non-limiting case study on implementation of the application is as follows：

Embodiment 1

The experimental provision of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources is repaired based on Zero-valent Iron-PRB reduction, including：According to Water supply installation 1, cylinder simulator 2 and the waste collecting device 4 of secondary pipeline connection, the cylinder simulator 2 are equipped with one Group sampling apparatus 3；The cylinder simulator 2 includes cylinder, and the both ends of the cylinder are equipped with water inlet end cylinder lid 5 and water outlet Cylinder lid 6, two cylinders, which cover, is respectively equipped with inlet opening 10 and apopore 11, is set respectively on the inlet opening 10 and apopore 11 Have pneumatic tube, sieve be equipped between cylinder lid and cylinder, be equipped with successively in cylinder the first filter layer 14, DNAPL contaminated areas 7, PRB regions 8,9 and second filter layer 15 of PRB downstream areas, the 7 corresponding damaged surface of DNAPL contaminated areas are equipped with DNAPL Injection hole 16, the PRB regions 8 and 9 corresponding damaged surface of PRB downstream areas are equipped with one group of top thieff hatch 17；It is described to adopt Sampling device 3 is set in top thieff hatch 17.Water-supply-pipe 18 between the water supply installation 1 and cylinder simulator 2 is equipped with compacted Dynamic pump 19.Outlet pipe 20 between the cylinder simulator 2 and waste collecting device 4 is equipped with sampling apparatus.The DNAPL Injection hole 16 is 6.5cm apart from inlet opening 10；Top thieff hatch 17 apart from inlet opening 10 be followed successively by 8 cm, 9.5cm, 11cm, 12.5cm, 15.5cm, 18.5cm, 21.5cm, 24.5cm, 30.5cm, 36.5cm and 66.5 cm.The sampling apparatus 3 be with The 20-gauge stainless steels sampling probe 21 of female Luer, one end of sampling probe are inserted perpendicularly into water-bearing layer by top thieff hatch 17, separately One end is connect with the check valve 22 with female Luer, and the external tapping of check valve 22 is equipped with micro syringe 23.It is described in cylindricality The uniform filled media in subregion in groove body, including：Grain size is the quartzy fine sand of 60-150 mesh, and grain size is in the quartz of 35-80 mesh The Zero-valent Iron that sand, grain size are the quartzy coarse sand of 4-35 mesh and grain size is 100-300 mesh；DNAPL contaminated areas 7 and PRB catchments 9 filled media of domain is fine sand, and control group and the selection of the filled media in experimental group PRB regions 8 are necessary to ensure that oozing for the region Water coefficient is more than the infiltration coefficient of DNAPL contaminated areas 7 and PRB downstream areas 9；8 filled media of experimental group PRB regions is Zero-valent Iron It is 1 with sand mass ratio in quartz:5 homogeneous mixture, control group such as then fill at the sand in quality quarts；The pretreatment of filled media It is characterized in that, the quartz sand respectively uses 0.1M NaOH and 0.1M HNO₃6h is impregnated, neutrality is washed till using deionized water 105 DEG C of baking oven drying afterwards；The Zero-valent Iron uses 0.1M NaOH and 0.1M HNO respectively₃It is rapid to repeat to wash three times, using going After ion is washed to neutrality, dries and preserve in vacuum freeze drier.The medium filling method includes the following steps：It fills out Cylindricality groove body is placed vertically during filling, according to the second filter layer 15, PRB downstream areas 9, PRB regions 8, DNAPL contaminated areas 7 It is filled successively with the first filter layer 14；PRB downstream areas 9 and DNAPL contaminated areas 7 and 8 medium of control group PRB regions Filling use wet filling mode；The simulated groundwater of deoxygenation from apopore 11 is injected using peristaltic pump 19, uses funnel The hollow pipe for being less than 1/2 groove body internal diameter with internal diameter adds in the clean fine sand dried and sterilized, layering filling, often fills 3cm and disturbs Dynamic pressure is primary in fact, ensures that horizontal plane is higher than layer of sand face 2cm-5cm in wet filling process；The filling of 8 medium of experimental group PRB regions is adopted With dry-packing mode；ZVI with middle sand is uniformly mixed using absolute ethyl alcohol before filling, is less than 1/2 groove body using funnel and internal diameter Sand mixture layering filling in uniformly mixed ZVI- to PRB regions 8, often filling 3cm are compacted primary, pressure by the hollow pipe of internal diameter The suffered disturbance of filled media should be made small as possible during real；After filling, apopore 11 is sealed, after groove body is stood for 24 hours vertically Water inlet end cylinder lid 5 with cylindricality groove body is connect, the cylinder simulator 2 after connection is sealed, horizontal rest is for 24 hours；Connect successively Water supply installation 1, cylinder simulator 2 and waste collecting device 4 are connect, is pumped the simulated groundwater of deoxygenation using peristaltic pump 19 Enter saturated aqueous layer simulator trial operation 6h, to remove the impurity introduced in filling process.Dirt in the DNAPL contaminated areas Dye object is dyed first using oil red O, and colouring method is：It weighs 0.0005g oil red O powder and is dissolved in 100mL DNAPL liquid In body, DNAPL dyeing liquids are obtained.The experimental method of described device, the experimental method include the following steps：A. it carries out first The connection of cylinder simulator 2 and sampling apparatus 3；B. Filled Dielectrics and experimental provision trial operation are then carried out；C. 1mL glass is used For glass micro syringe from the DNAPL of the injection dyeing of DNAPL injection holes 16, charge velocity is 0.5 μ L/min；D. after the completion of injecting, 5cm long and one end are inserted into inlet opening 10 in the pneumatic tube of apopore 11, making respectively using the PTFE tube of silica gel sealing in advance Cylinder seals, and standing makes DNAPL Stable distritations for 24 hours；E. it is sequentially connected water supply installation 1, cylinder simulator 2 and waste liquid again Collection device 4 is pumped into the simulated groundwater of deoxygenation using peristaltic pump 19；F. timing acquires sample from thieff hatch, to pollutant Ingredient and concentration are detected, and sample collection rate should be less than 2% that simulated groundwater body is pumped into rate.

Embodiment 2

As shown in the figure, the experiment dress of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources is repaired in a kind of Zero-valent Iron-PRB reduction It puts and method, including water supply installation 1, cylinder simulator 2, sampling apparatus 3 and waste collecting device 4.

The length of the cylinder simulator 2 is 50cm, internal diameter 5cm, outer diameter 6cm, is simulated including saturated aqueous layer Region and both ends filter layer.Saturated aqueous layer simulated domain includes DNAPL contaminated areas 7, PRB regions 8 and PRB downstream areas 9.Its The length of middle DNAPL contaminated areas 7 is 5cm, and PRB regions 8 are mounted on the position of 16 downstream 2cm of distance DNAPL injection holes, length For 20cm, the length of PRB downstream areas 9 is 15cm.Both ends filter layer includes the first filter layer 14 and the second filter layer 15, long Degree is respectively 3cm and 1.5cm.The internal diameter of DNAPL injection holes 16 is 0.4cm and thieff hatch 17 internal diameter in top is 0.2cm.

2 filling process of cylinder simulator is placed vertically, and experimentation is horizontal positioned, at the top of cylindricality groove body in proportion Arrangement DNAPL injection holes 16 and top thieff hatch 17,3 syringe needle of sampling apparatus are in same horizontal line, are respectively positioned in 1/2 cylinder At diameter.

The white quartz sand that experimental selection purity is 99.4% uses 0.1M NaOH, 0.1M as porous media before filling HNO₃After impregnating 6h respectively, neutrality is washed till using deionized water, 105 DEG C of baking oven drying is placed on, is killed using preceding using ultraviolet light Bacterium 2h.One of the filled media of the zeroth order iron powder that selection purity is 99.0% as PRB regions 8,0.1 M is used before filling NaOH and 0.1M HNO₃Be soaked respectively foam washing three times, the time is respectively 3min, after being washed till neutrality using deionized water vacuum refrigeration do It is dry, Zero-valent Iron is uniformly mixed with middle sand using ethyl alcohol before cylinder filling.The main reason for being mixed using ethyl alcohol has two (1) powder Last shape Zero-valent Iron and middle sand specific gravity difference are big, and dry-mixing can not be uniformly mixed；(2) implement mixing using ethyl alcohol can effectively avoid The Quick Oxidation of Zero-valent Iron.

Before cylinder filling, first by all experiment equipment ultraviolet-sterilizations, sampling apparatus 3 is connected, by stainless steel sampling needle 21 It is passed through from 26 center of silica gel plug, the distance for making needle point to 26 bottom of silica gel plug is 3cm；Then it will be blocked up using silica gel with silica gel First 26 assembled stainless steel sampling needle 21 is sequentially fixed on cylindricality groove body DNAPL injection holes 16 and top thieff hatch 17, most Connection stainless steel sampling needle 21 and check valve 22 afterwards, use silica gel sealing connecting portion.During sample collection, check valve 22 is opened, The position that micro glass syringe 23 is inserted into i.e. 1/2 internal diameter of cylinder of 21 needle position of stainless steel sampling needle slowly acquires sample.

After sampling apparatus is fixed, water inlet end cylinder lid 5 is connected with water outlet cylinder lid 6 and cylindricality groove body respectively, and first Apopore 11 is first sealed, inlet opening 10 is sealed after filling deionized water from water inlet end, horizontal and vertical placement respectively carries out each for 24 hours The air tightness test at position.

After air tightness test, open water inlet end cylinder lid 5, successively according to the second filter layer 15, PRB downstream areas 9, PRB regions 8, the sequence progress cylinder filling of DNAPL contaminated areas 7, the first filter layer 14.Cylindricality groove body is put vertically in filling process It puts, water outlet is bottom.Wherein in addition to PRB regions are using dry-packing, remaining region is filled using wet method.Wet method is filled from bottom Water inlet makes water level line be consistently higher than layer of sand 2cm-5cm, and often filling 3cm disturbs compacting successively with rubber hammer.It fills to PRB areas During domain, make water level concordant with layer of sand using siphon method first, it then will be in advance using the Zero-valent Iron that ethyl alcohol is uniformly mixed in Sand mixture is filled to PRB regions, often fills 5cm, and compacting is primary.After filling, slowly from bottom, water inlet makes water level line again It is secondary to be higher than layer of sand 3cm, the filling in other regions is carried out successively.

After the completion of filling, water inlet end cylinder lid is connect and sealed with cylindricality groove body, place 48h vertically, nothing is engraved in cylinder After empty or bubble it is horizontal positioned for 24 hours, water supply installation 1, cylinder simulator 2 and useless are sequentially connected after still being generated without hollow out or bubble Liquor collecting device 4.

Ingredient is represented using carbon tetrachloride as DNAPL.Using 1mL glass syringes, (0.5mL is injected every time) in two times Dyeing DNAPL is slowly injected into DNAPL contaminated areas 7 from DNAPL injection holes 16.Injection mode is：With 0.5 μ L/min of rate DNAPL contaminated areas 7 are injected, injection for the first time and second of injection interval 10-20min ensure that the DNAPL of injection for the first time is complete Second of injection is carried out again behind full infiltration DNAPL contaminated areas.After the completion of double injection, DNAPL injection holes 16 and cylinder are simulated Device seals, and water supply installation 1, cylinder simulator 2 and waste collecting device 4, running experiment device are reconnected after standing 6h.

In cylinder operational process, simulated groundwater flow velocity is 0.145m/d, and peristaltic pump is pumped into rate as 0.2mL/min, During experiment carries out, timing water sampling, sampling rate is no more than the 5% of groove body water velocity, is 4 μ L/min.Ensureing foot Under the premise of enough samples are for quantitative chemical analysis, the single sample volume of each thief hole is in 10 μ L.Water sample is acquired through dilution It is measured afterwards using headspace gas chromatography.

Headspace gas chromatography instrument matches electron capture detector (ECD), DB-624 capillary columns (60m × 250 μ m, 1.4 μ m).Column flow is 1mL/min, and carrier gas is high pure nitrogen, and the maximum temperature of syringe and baking oven is 220 DEG C, and Monitoring lower-cut is 1 μ g/L。

Water phase pollutant concentration is made according to the variation of pollutant concentration in thieff hatch water samples different in experiment at any time to become The curve graph (Fig. 3-a, Fig. 3-b) of change, wherein Fig. 3-a are DNAPL pollution sources variation characterization hole 2# pollutant concentration change curves. In the presence of DNAPL, the variation that 2# holes acquire sample contaminant concentration shows as gradually rising up to DNAPL from 0 existing Dissolution equilibrium concentration in water, and remained unchanged in the equilibrium concentration.After DNAPL is completely dissolved, due to the disappearance of pollution sources Water phase pollutant concentration progressively decreases to 0.In Zero-valent Iron-PRB restores reparation system (i.e. experimental group), DNAPL is in water A concentration of DNAPL of dissolution equilibrium is codetermined to the dissolving of water phase and the reduction dechlorination of solubilised state DNAPL ingredients.In no zeroth order In iron-PRB reduction reparation system (i.e. control group), the dissolution equilibrium concentration of DNAPL in water is only from DNAPL to the molten of water phase Solution determines.The existence time of DNAPL phases is the persistence of DNAPL pollution sources in DNAPL pollution sources.Fig. 3-b are 9# holes Zhong Shui The variation of phase pollutant concentration, the thieff hatch are located at PRB downstream areas, are mainly used in the underground water that monitoring flows through PRB walls The ingredient and concentration of pollutant, so as to characterize the validity of Zero-valent Iron-PRB walls.Fig. 3-c be the application in application process Mass balance calculation by mass balance calculation, characterizes the laboratory feasibility of the application device and method.

Zero-valent Iron-RPB mainly by Zero-valent Iron reduction of dissolved state DNAPL ingredients, enhances the reparation of DNAPL pollution sources What the dissolving of the opposite water phases of DNAPL was realized.It can be assessed zero under the technology by the variation of control group and experimental group curve concentration Remediation efficiency of the solubilised state DNAPL ingredients to DNAPL pollution sources is repaired in valency iron-PRB reduction.Compared with the control group, Zero-valent Iron- PRB reduction repair solubilised state DNAPL ingredients can significantly reduce DNAPL pollution sources persistence (Fig. 3-a DNAPL pollution sources Persistence reduces 30%-40%)；In Fig. 3-b, in the simulated groundwater for flowing through PRB regions compared with the control group, in experimental group The DNAPL ingredient aqueous concentrations of solubilised state reduce 600mg/L-700mg/L, and the DNAPL there are about 80% is dissolved into underground water And restored and remove by Zero-valent Iron-PRB, illustrate that 20cm PRB length can effectively degrade the DNAPL ingredients of solubilised state.But this DNAPL used is reacted with the reduction dechlorination of Zero-valent Iron using carbon tetrachloride as ingredient, carbon tetrachloride is represented to take off step by step in case Chlorine process, dechlorination intermediate product chloroform only have 10% and are further restored by Zero-valent Iron-PRB, and chloroform is dense in water outlet Degree is up to 590mg/L.In view of the control to intermediate product aqueous concentration, PRB long can be appropriately extended in actual place application Degree simultaneously repairs intermediate product.Fig. 3-c are control group and pollutant molal quantity conservation meter in experimental group in experimentation It calculates.The sum of the sum of each pollutant molal quantity of experimental group and each pollutant molal quantity of control group are of substantially equal.Compared with the control group, it is real Mole loss for testing in group about 13% may be from the unknown product not yet detected in experimentation.

Applicant states that above-mentioned case study on implementation is mainly used for the detailed construction feature and implementation method for illustrating the application, but It is not limited to above-mentioned detailed construction feature and implementation method, that is to say, that do not mean that the application must be according to above-mentioned detailed knot Structure feature and method could be realized.The those skilled in the relevant art are it will be clearly understood that any improvement to this application, including to making It is carried out with the equivalence replacement of component and the increase of accessory, the selection of concrete mode and by any suitable means Combination etc., should all be considered as content disclosed in the present application, belong within the protection domain and the open scope of the application.In order to keep away Exempt from unnecessary repetition, the application is replaced by various possible parts and various combinations of possible ways no longer separately illustrate.

Claims (5)

1. repairing the experimental provision of saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources based on Zero-valent Iron-PRB reduction, feature exists In including：The water supply installation of pipeline connection successively（1）, cylinder simulator（2）And waste collecting device（4）, the cylinder mould Intend device（2）It is equipped with one group of sampling apparatus（3）；The cylinder simulator（2）Including cylinder, the both ends of the cylinder are equipped with Water inlet end cylinder lid（5）With water outlet cylinder lid（6）, two cylinders cover and are respectively equipped with inlet opening（10）And apopore（11）, The inlet opening（10）And apopore（11）On be respectively equipped with pneumatic tube, sieve is equipped between cylinder lid and cylinder, in cylinder according to It is secondary to be equipped with the first filter layer（14）, DNAPL contaminated areas（7）, PRB regions（8）, PRB downstream areas（9）With the second filter layer （15）, the DNAPL contaminated areas（7）Corresponding damaged surface is equipped with DNAPL injection holes（16）, the PRB regions（8）And PRB Downstream area（9）Corresponding damaged surface is equipped with one group of top thieff hatch（17）；The sampling apparatus（3）Set on top thieff hatch （17）It is interior.

2. saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources are repaired based on Zero-valent Iron-PRB reduction according to claim 1 Experimental provision, it is characterised in that the water supply installation（1）With cylinder simulator（2）Between water-supply-pipe（18）It is equipped with and wriggles Pump（19）.

3. saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources are repaired based on Zero-valent Iron-PRB reduction according to claim 1 Experimental provision, it is characterised in that the cylinder simulator（2）And waste collecting device（4）Between outlet pipe（20）It is equipped with Sampling apparatus.

4. saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources are repaired based on Zero-valent Iron-PRB reduction according to claim 1 Experimental provision, it is characterised in that the DNAPL injection holes（16）Apart from inlet opening（10）6.5 cm；Top thieff hatch（17）Distance Inlet opening（10）Be followed successively by 8 cm, 9.5 cm, 11 cm, 12.5 cm, 15.5 cm, 18.5 cm, 21.5 cm, 24.5 cm, 30.5 cm, 36.5 cm and 66.5 cm.

5. saturated aqueous layer chlorinated hydrocarbon DNAPL pollution sources are repaired based on Zero-valent Iron-PRB reduction according to claim 1 Experimental provision, it is characterised in that the sampling apparatus（3）To carry the 20-gauge stainless steel sampling probes of female Luer（21）, take One end of sample needle is by top thieff hatch（17）It is inserted perpendicularly into water-bearing layer, the other end and the check valve with female Luer（22）Even It connects, check valve（22）External tapping be equipped with micro syringe（23）.