Integral method is repaired in a kind of contaminated site groundwater treatment-soil heterotopic drip washing
Technical field
The invention belongs to contaminated site and repair the field, relate in particular to soil and the underground water reparation of contaminated site.
Background technology
Along with the quickening of expanding economy and city-building speed, the change of place character is also frequent further.Many industrial enterprises move away from the city successively, and original industrial land is developed as residential estate, school's land used or Gongjian's land used gradually.But worker's business activity for many years causes plant area's soil and phreatic severe contamination, and the health that may endanger the resident.Therefore, the repairing and treating task in pollution worker enterprise place is very urgent.
At present, soil remediation method mainly contains physics repairing method, chemical repairing method and biological restoration method etc. both at home and abroad.But there is the cost height in some method, repairs deficiencies such as not thorough, that repairing efficiency is long, environmental influence is big, is difficult for extensive use.Soil drip washing recovery technique is a kind of chemical leaching technology rapidly and efficiently, is one of soil remediation method of twentieth century end U.S. EPA recommendation.Can be divided into original position drip washing and dystopy drip washing according to the processing mode difference.The original position elution method is directly eluent to be injected soil, in the downstream leacheate extracting is gone out soil surface, then leacheate is handled, and so continues to carry out, and reaches relevant criterion up to soil environment quality.But this method only is applicable to that hydraulic conductivity is greater than 10
-3The porous crack of cm/s, easily permeate soil, limited its range of application greatly.Dystopy drip washing is that soil is excavated, and drops in the container, adopts leacheate to clean and removes pollutant in soil, handles the leacheate that contains pollutant at last.This method can be used for the repairing and treating of contaminated soils such as heavy metal, radionuclide, petroleum hydrocarbon, polycyclic aromatic hydrocarbon, Polychlorinated biphenyls, organo-chlorine pesticide, and the scope of application is very wide, have simultaneously repairing efficiency short, remove efficient height, advantage such as easy and simple to handle.One of key issue that the dystopy ELUTION METHOD need solve is the recycling of leacheate.At present, people mainly adopt active carbon to realize the recycling of leacheate.Though it is functional that active carbon is adsorbed with organic pollutants, the less and discarded active carbon of saturated adsorption capacity is difficult for regeneration or re-uses, thus cause application cost higher, cause secondary pollution easily.And through the organobentonite that organic reagent (as quaternary surfactant) modification makes, be a kind of sorbing material of economical and efficient, have characteristics such as structure-function is adjustable, saturated adsorption capacity is big, raw material is easy to get, absorption property is good.And discarded organobentonite can be used for preparing the mesopore nano material, is used for the adsorption cleaning of room air pollution.Therefore, the present invention intends adopting organobentonite as adsorbent.
Business activity for many years, plant area's underground water also is subjected to pollution in various degree.For ensureing human health and preventing that reclaimed soil from polluting bounce-back, also need underground water is carried out repairing and treating.Extraction-facture is one of a kind of groundwater treatment method rapidly and efficiently, is about to the underground water extracting and goes out soil surface, enters water treatment facilities, and the underground water after the purification directly recharges or enter water body.Need a large amount of waters in the soil heterotopic lessivation, the underground water after therefore handling can be directly used in the soil drip washing technology, realizes waste water recycling, conserve water resource.
Summary of the invention
The objective of the invention is the deficiency at existing treatment technology, provide a kind of contaminated site groundwater treatment-soil heterotopic drip washing to repair integral method.
The invention discloses a kind of contaminated site groundwater treatment-soil heterotopic drip washing and repair integral method, it is characterized in that its step is as follows:
(1) underground water that goes out of extracting enters the organobentonite adsorption column, removes organic pollution wherein;
(2) underground water after the purification enters tank;
(3) water in the tank and surfactant are added the ingredients pond, be made into leacheate;
(4) contaminated soil adopts multistage wet vibration sieve tentatively to sieve, and isolates stone and coarse sand.Coarse sand is directly sent into the drip washing pond and is cleaned;
(5) the soil suspension after the screening enters hydrocyclone and further sieves;
(6) isolate thin suspended particulate substance less than 0.05mm in the step (5) and add and enter plate and frame filter press after coagulant is handled, be pressed into mud cake.Mud cake is sent into thermal desorption system and is removed organic pollution, and soil is up to standard, backfill; The water direct reuse that extrudes sieves in wet vibration;
(7) soil particle of isolating greater than 0.05mm in the step (5) enters the drip washing pond, adds the leacheate in the step (3) simultaneously, adopts mechanical agitation and ultrasonic soil particle and the abundant mixing of leacheate of making; Soil reaches relevant criterion;
(8) after the ultrasonic end of the middle stirring of step (7), sedimentation 30 minutes; After the upper strata water after filtration, the organobentonite adsorption column purifies, send into the ingredients pond; Lower soil enters washing pool, to reduce surfactant concentration in the soil, enters plate and frame filter press again, is pressed into mud cake, backfill; The water that extrudes enters the reuse of ingredients pond;
(9) regulate surfactant concentration in the ingredients pond, be used for the drip washing of next group contaminated soil.
Described surfactant is anion, non-ionic surface active agent or both mixed surfactants.Described anion surfactant is lauryl sodium sulfate (SDS) or neopelex (SDBS), and non-ionic surface active agent is paregal O-25 or Tween 80.
The present invention be directed to contaminated site soil and phreatic repairing and treating.That this technology has is easy and simple to handle, controllability is strong, applied widely, characteristics such as removal effect is good, can be used for contaminated site soil and underground water recovery project.
Among the present invention, can adjust parameters such as this technology eluent composition, adsorbent consumption, stirring and ultrasonic time, thereby reach the planned land use environmental quality standards according to the differences such as character, pollutant kind and pollution level of underground water, soil.
Among the present invention, the underground water after the purification is directly used in the soil heterotopic drip washing technology, realizes waste water recycling.
Among the present invention, adopt organobentonite adsorption cleaning waste water, realize the reuse of leacheate, save cost.Adsorb saturated discarded organobentonite simultaneously and can be used for preparing the mesopore nano material, the adsorption cleaning room air pollution realizes refuse reclamation.
Description of drawings
Further specify this process below in conjunction with accompanying drawing.
Fig. 1 shows the flow chart that integral method is repaired in contaminated site groundwater treatment-soil heterotopic drip washing that is used for according to the embodiment of the invention.
The specific embodiment
Describe embodiments of the invention in detail below in conjunction with accompanying drawing.
Integral method is repaired in the groundwater treatment of present embodiment contaminated site-soil heterotopic drip washing, and step is as follows:
(1) underground water that goes out of extracting enters the organobentonite packed column, and the organic pollutant removal rate is more than 90%;
(2) underground water after the purification enters tank, for follow-up soil drip washing (not enough water running water replenishes);
This two step is groundwater treatment technology (frame of broken lines is interior in the accompanying drawing 1).
(3) water and the surfactant with tank adds the ingredients pond, is made into 0.1%~2% leacheate;
(4) contaminated soil utilizes multistage wet vibration sieve tentatively to sieve, one-level screening removal stone (>5mm), collect; Coarse sand is removed in the secondary screening, and (1~5mm), this part soil directly enters the drip washing pond;
(5) screening after soil suspension (<1mm) enter hydrocyclone further to sieve;
(6) isolate in the step (5) and add coagulant less than the fine grained suspension of 0.05mm and handle the laggard sheet frame filter press of going into, Separation of Solid and Liquid.Mud cake is sent into thermal desorption system, and soil is up to standard, backfill; The water direct reuse that extrudes sieves in wet vibration;
(7) soil particle of isolating greater than 0.05mm in the step (5) enters the drip washing pond, adds the leacheate in the step (3) simultaneously, adopts mechanical agitation and ultrasonic soil particle and the abundant mixing of leacheate of making, and soil and leacheate mass ratio are 1: 2~5.Mixing speed is 50~150rpm, and stirring ultrasonic time is 5~30 minutes.Soil reaches repairing standard;
(8) after the ultrasonic end of the middle stirring of step (7), sedimentation 30 minutes; Behind upper strata water process sand filtration, the organobentonite adsorption cleaning, enter the reuse of ingredients pond; Lower soil enters washing pool, shows surfactant concentration to reduce in the soil, and soil is 1: 2~5 with the water quality ratio, and mixing speed is 50~150rpm, and stirring ultrasonic time is 5~20 minutes.Stir ultrasonic end back sedimentation 30 minutes, the upper strata water enters the ingredients pond, and lower floor's soil phase enters plate and frame filter press, the mud cake backfill; The water that extrudes enters the ingredients pond;
(9) regulate surfactant concentration in the ingredients pond, be used for the drip washing of next group contaminated soil.
Utilize the present invention to repair underground water and the soil of contaminated site, the result shows:
1, polluted underground water is after the organobentonite adsorption treatment, and the clearance of DDT, BHC, BaP is (DDT, BHC initial concentration are respectively 3.9 μ g/L, 46.7 μ g/L) more than 90%.
2, contaminated soil is after 0.5% peregal 0-25 and SDBS mixed surfactant (mass ratio 9: 1) cleaning, and DDT, BaP concentration are reduced to the reparation desired value.
3, leacheate is behind the organobentonite adsorption cleaning, and the surfactant rate of recovery is more than 80%.
In addition to the implementation, the present invention also has other embodiment.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of requirement of the present invention.