CN111085536B

CN111085536B - Soil remediation process

Info

Publication number: CN111085536B
Application number: CN201911415558.5A
Authority: CN
Inventors: 刘晨; 万建成; 王亮; 石敦敦; 许卫峰; 宋楠; 王浩; 吴滨涛
Original assignee: Hangzhou Shenyuan Environmental Technology Co ltd
Current assignee: Hangzhou Shenyuan Environmental Technology Co ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-08-03
Anticipated expiration: 2039-12-31
Also published as: CN111085536A

Abstract

The invention discloses a soil remediation process, which comprises the following steps: s1, feeding, namely conveying the polluted soil into a screening machine through a conveyor for screening treatment; s2, washing and screening, washing the soil on the screen by high-pressure water, washing the soil into muddy water by the high-pressure water, and allowing the muddy water to fall off the screen, wherein broken stones in the soil are left on the screen; s3, filter pressing and electroosmosis treatment, wherein a direct current electric field is added between two adjacent plate frames while filter pressing is carried out on the plate frame filter press, so that heavy metal pollutants are transferred to a water body and are discharged from the filter press along with the water body; s4, water treatment, wherein a molecular sieve mechanism is arranged on a drain pipe of the filter press to filter the water body filtered by the filter press; and S5, recycling, namely transporting the soil subjected to pressure filtration by the pressure filter to a specified site by a muck truck for recycling. The soil remediation process has the effect of reducing secondary pollution to soil, and is simple and convenient in whole process, easy to implement and low in remediation cost.

Description

Soil remediation process

Technical Field

The invention relates to the technical field of polluted soil treatment, in particular to a soil remediation process.

Background

The heavy metal pollution of the soil refers to the condition that the content of trace metal elements in the soil exceeds a background value and is over-high due to excessive deposition because of human activities, and the condition is generally called as soil heavy metal pollution. Heavy metals polluting soil mainly comprise elements with obvious biological toxicity, such As mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), metalloid arsenic (As) and the like, and elements with certain toxicity, such As zinc (Zn), copper (Cu), nickel (Ni) and the like. Mainly comes from pesticides, waste water, sludge, atmospheric sedimentation and the like, if mercury mainly comes from mercury-containing waste water, cadmium and lead pollution mainly comes from smelting emission and automobile waste gas sedimentation, and arsenic is widely used as an insecticide, a bactericide, a rodenticide and a herbicide. Excessive heavy metal can cause physiological dysfunction and nutritional disorder of plants, the enrichment coefficient of elements such as cadmium, mercury and the like in crop seeds is higher, even if the enrichment coefficient exceeds the food sanitation standard, the growth, development and yield of crops are not influenced, and in addition, mercury and arsenic can weaken and inhibit the activities of nitrifying and ammonifying bacteria in soil and influence the nitrogen supply. Heavy metal pollutants have very low mobility in soil, are not easy to leach with water, are not degraded by microorganisms, and have great potential hazard after entering a human body through a food chain, a stone dumping site and a tailing pond are not established in some mines during mining, waste stones and tailings are randomly stacked, so that the tailings are rich in refractory heavy metals and enter the soil, and in addition, the metal waste residues remained after ore processing enter an underground water system along with rainwater, so that severe soil heavy metal pollution is caused.

The notice number is: CN110038890B discloses a method for restoring ecological environment-friendly soil, which is characterized in that: the method comprises the following steps: uniformly scattering the soil remediation agent on the surface of the heavy metal contaminated soil, then carrying out soil turning to fully and uniformly mix the soil remediation agent and the heavy metal contaminated soil, and balancing for 6-8 days to finish the soil heavy metal remediation process; the soil remediation agent is prepared by mixing 55-65 parts by weight of modified hectorite, 20-30 parts by weight of organic fertilizer, 10-20 parts by weight of humic acid and 1-3 parts by weight of microbial agent, wherein the modified hectorite is prepared by the following method: calcining hectorite, adding a mixed modifier, stirring for reaction, performing microwave irradiation treatment while stirring, and finally grinding into particles or powder, wherein the stirring reaction is performed at the temperature of 280-320 ℃ for 1 hour; the amount of the mixed modifier accounts for 10 wt% of the modified hectorite, the mixed modifier is composed of calcium polysulfide and a modifier I according to the mass ratio of 2:1, and the structural formula of the modifier I is as follows: the viable count of the microbial inoculum is 1.5-2.5 hundred million per gram.

The ecological environment-friendly soil remediation method needs to spread a soil remediation agent on the soil polluted by heavy metals, and remediation is carried out in a chemical remediation mode, so that although the heavy metal pollutants in the soil can be removed, the soil remediation agent spread on the soil still causes secondary pollution to a certain degree, and therefore a soil remediation method with less secondary pollution to the soil is needed at present.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a soil remediation process which has the effect of reducing secondary pollution to soil.

The above object of the present invention is achieved by the following technical solutions:

the soil remediation process is characterized by comprising the following steps:

s1, feeding, namely conveying the polluted soil into a screening machine through a conveyor for screening treatment;

s2, washing and screening, washing the soil on the screen by high-pressure water, washing the soil into muddy water by the high-pressure water, and enabling the muddy water to fall off from the screen, and reserving broken stones in the soil on the screen, so that screening is realized;

s3, performing filter pressing electroosmosis treatment, namely conveying the mud water discharged from the screening machine into a plate frame filter press through a conveyor for filter pressing, adding a direct current electric field between two adjacent plate frames while performing filter pressing on the plate frame filter press, transferring heavy metal pollutants in the soil into a water body through an electroosmosis technology, and discharging the heavy metal pollutants together with the water body from the filter press;

s4, water treatment, wherein a molecular sieve mechanism is arranged on a drain pipe of the filter press, and when water body filtered by the filter press passes through the molecular sieve mechanism, heavy metal pollutants are adsorbed and fixedly sealed in the molecular sieve mechanism; the molecular sieve mechanism comprises a connecting block connected with a drain pipe of the filter press, the connecting block is provided with a drain channel with two ends penetrating through, one end of the drain channel is a water inlet, the other end of the drain channel is a water outlet, the drain channel is horizontally and transversely arranged, the drain channel is communicated with the drain pipe of the filter press, the connecting block is provided with a feed channel mutually communicated with the drain channel, the feed channel is vertically arranged and positioned above the drain channel, a plurality of stacked molecular sieves are arranged in the feed channel in a vertically sliding manner, the lowest molecular sieve is positioned in the drain channel, a limiting part for blocking the molecular sieves is connected in the drain channel at one side opposite to the water outlet in a threaded manner, the outer wall of the molecular sieve in the drain channel is in clearance fit with the inner wall of the drain channel, the connecting block is provided with a blanking channel communicated with the drain channel, the blanking channel is vertically arranged and positioned below the drain channel, the feeding channel and the blanking channel are arranged in a left-right staggered mode, the feeding channel is arranged close to one side of the water inlet, the blanking channel is arranged close to one side of the water outlet, the limiting piece comprises a spring and a ring body in threaded connection with the inner wall of the drainage channel, one end of the spring abuts against the molecular sieve in the drainage channel, and the other end of the spring is connected with the ring body;

and S5, recycling, namely transporting the soil subjected to pressure filtration by the pressure filter to a specified site by a muck truck for recycling.

By adopting the technical scheme, the soil containing heavy metals forms muddy water after passing through the screening machine, the muddy water is introduced into the plate-and-frame filter press for filter pressing, a direct current electric field is additionally added while the filter pressing is carried out by the filter press, so that the muddy water generates an electroosmosis phenomenon in the pressing process, heavy metal pollutants are migrated out and are discharged out of the filter press along with water, the effect of removing the heavy metal pollutants in the soil is achieved by combining the electroosmosis and the filter pressing, no chemical agent is used, the secondary pollution to the soil can be greatly reduced, the effect of soil remediation is better, meanwhile, the whole process is simple and convenient, the implementation is easy, and the remediation cost is low; when a water body containing heavy metals passes through the molecular sieve mechanism, heavy metal pollutants can be adsorbed and fixedly sealed in the molecular sieve mechanism, the molecular sieve needs to be replaced after the water body containing heavy metals is used for a period of time, otherwise, the water discharge pipe of the filter press is easily blocked, by adopting the technical scheme, a plurality of stacked molecular sieves are arranged in the connecting block in advance, water in the water discharge channel can directly pass through the lowest molecular sieve and is filtered through the lowest molecular sieve, when the lowest molecular sieve needs to be replaced, only the limiting part needs to be opened, the lowest molecular sieve is pulled out, the second molecular sieve above can fall into the water discharge channel for filtering, the limiting part is arranged after the replacement is finished, the whole process is very coherent, and the replacement is very convenient; after the molecular sieve at the bottom is used for a period of time, the amount of heavy metal pollutants sealed on the molecular sieve can be gradually increased, so that the flow rate of the water body can be slowed down, the acting force of the water body acting on the molecular sieve can be gradually increased, the molecular sieve at the bottom can be pushed to move towards one end of the water outlet, after the molecular sieve at the bottom is completely moved away from the lower part of the second molecular sieve, the second molecular sieve can automatically fall into the drainage channel, the molecular sieve at the bottom can fall into the discharging channel, the automatic replacement of the molecular sieve can be realized, manual replacement is not needed, the replacement is simpler and more convenient, the machine does not need to be stopped for replacement, and the working efficiency can be greatly improved.

The invention is further configured to: and (4) detecting the metal content of the soil in the S5, if the soil passes the detection, transporting the soil to a specified site through a muck truck for recycling, and if the metal content exceeds the standard, re-conveying the soil exceeding the standard into the screening machine.

Through adopting above-mentioned technical scheme, detect the soil after the filter-pressing, the soil that accords with the index can be carried other places and carry out recycle, and the filter-pressing is restoreed in carrying the filter-pressing once more to the not regulation to can further reduce the secondary pollution to soil.

The invention is further configured to: and discharging the water treated in the S4 into a water storage tank, wherein the water in the water storage tank is adopted as the high-pressure water in the S2.

Through adopting above-mentioned technical scheme, the water discharge after will handling stores in the tank, then applies the washing away of screening machine to soil again for the water resource can be by cyclic utilization, water economy resource greatly.

The invention is further configured to: and the horizontal transverse distance between the central axis of the feeding channel and the central axis of the blanking channel is more than half of the sum of the horizontal width of the feeding channel and the horizontal width of the blanking channel.

Through adopting above-mentioned technical scheme, feed channel and unloading passageway are stagger completely about, like this when the below molecular sieve removes the back from second molecular sieve below whole, second molecular sieve can drop in the drainage channel, and the molecular sieve of below still can be in the drainage channel, after the heavy metal pollutant volume that seals continues to increase, the water can promote two molecular sieves and move backward together, make in the later molecular sieve can drop the unloading passageway, so circulate, such structure, make water have the molecular sieve to filter the water always when flowing through from the drainage channel, make the filter effect better.

The invention is further configured to: feed channel up extends to and forms the feed inlet outside the connecting block, unloading passageway down extends to and forms the discharge gate outside the connecting block, connecting block threaded connection has the first sealed lid that is used for sealed feed inlet, connecting block threaded connection has the sealed lid of second that is used for sealed discharge gate.

By adopting the technical scheme, when a new molecular sieve is required to be placed in the feeding channel, the molecular sieve can be directly added into the feeding channel through the feeding hole without being added into the feeding channel through the drainage channel, so that the molecular sieve is more convenient to add; when the old molecular sieve is to be removed, the second sealing cover can be opened to take the old molecular sieve, so that the molecular sieve is more convenient to take.

The invention is further configured to: the connecting block lateral wall is equipped with the first slot with feedstock channel intercommunication, it is used for sealed feedstock channel's first closing plate to be provided with in the slot with sliding, first closing plate outer wall and the sealed cooperation of first slot inner wall, the connecting block lateral wall is equipped with the second slot with feedstock channel intercommunication, it is used for sealed feedstock channel's second closing plate to be provided with in the slot with sliding, the sealed cooperation of second closing plate outer wall and second slot inner wall, first slot and second slot all are close to drainage channel and set up.

Through adopting above-mentioned technical scheme, drainage channel is at the in-process of drainage, can seal feed channel through first closing plate, just so can add new molecular sieve in the feed channel, can seal discharge channel through the second closing plate, just so can open the sealed lid of second and make the molecular sieve in the discharge channel drop out, such structure makes and just can add new molecular sieve and take old molecular sieve at the in-process of drainage, do not need to shut down and operate, can improve work efficiency greatly.

The invention is further configured to: the inner of the first sealing plate and the inner of the second sealing plate are both provided with limiting blocks, and the thickness of the first sealing plate and the thickness of the second sealing plate are both smaller than the thickness of the limiting blocks.

Through adopting above-mentioned technical scheme, the stopper can first closing plate and second closing plate play spacing effect for first closing plate and second closing plate are difficult for dropping out from the connecting block.

In conclusion, the beneficial technical effects of the invention are as follows:

the soil is restored by combining filter pressing and electroosmosis, secondary pollution to the soil can be reduced by adopting a physical method, and meanwhile, the whole process is simple and convenient, easy to implement and low in restoration cost.

Drawings

FIG. 1 is a schematic diagram of the structure of the molecular sieve mechanism of the present invention;

FIG. 2 is a front view of a molecular sieve of the present invention;

in the figure, 1, a water drainage pipe; 2. a molecular sieve mechanism; 3. connecting blocks; 4. a drainage channel; 5. a water inlet; 6. a water outlet; 7. a feed channel; 8. a molecular sieve; 9. a limiting member; 10. a blanking channel; 11. a spring; 12. a ring body; 13. a feed inlet; 14. a discharge port; 15. a first sealing cover; 16. a second sealing cover; 17. a first slot; 18. a first sealing plate; 19. a second slot; 20. a second sealing plate; 21. a limiting block; 22. a seal ring; 23. a pipe body; 24. a net cover; 25. a zeolite.

Detailed Description

The invention discloses a soil remediation process, which comprises the following steps:

s2, washing and screening, namely pumping water in the water storage tank to soil through a high-pressure water gun, washing the soil into muddy water by the high-pressure water, and enabling the muddy water to fall off a screen, and enabling broken stones in the soil to be left on the screen, so that screening is achieved;

s3, performing filter pressing electroosmosis treatment, namely conveying the mud water discharged from the screening machine into a plate frame filter press through a conveyor for filter pressing, adding a direct current electric field between two adjacent plate frames while performing filter pressing on the plate frame filter press, wherein one plate frame is connected with an anode, the other plate frame is connected with a cathode, and the heavy metal pollutants in the soil are transferred into a water body through the electroosmosis technology and are discharged from the filter press along with the water body;

s4, water treatment, wherein a molecular sieve mechanism 2 is arranged on a drain pipe 1 of a filter press, heavy metal pollutants are adsorbed and fixedly sealed in the molecular sieve mechanism 2 when a water body filtered by the filter press passes through the molecular sieve mechanism 2, and the treated water body is discharged into a water storage tank;

And S6, detecting the metal content of the soil in the S5, if the soil passes the detection, transporting the soil to a designated site through a muck truck for recycling, and if the metal content exceeds the standard, re-transporting the soil exceeding the standard into a screening machine.

Referring to fig. 1, molecular sieve mechanism 2 includes connecting block 3, and the last drainage channel 4 that runs through about being equipped with of connecting block 3, and drainage channel 4's left end is water inlet 5, and the right-hand member is delivery port 6, and connecting block 3 passes through threaded connection with drain pipe 1 of pressure filter, is equipped with the external screw thread at drain pipe 1 outer wall, is equipped with the internal thread in drainage channel 4's inside, after connecting block 3 and drain pipe 1 fixed connection, the horizontal setting of drainage channel 4 level in connecting block 3.

Set up the feedstock channel 7 that is linked together with drainage channel 4 down at the upper surface of connecting block 3, unloading passageway 10 has up been seted up at the lower surface of connecting block 3, feedstock channel 7 misplaces each other about the equal vertical setting of unloading passageway 10, horizontal transverse distance between the axis of feedstock channel 7 and the axis of unloading passageway 10 is greater than the half of 7 horizontal width of feedstock channel and the sum of the 10 horizontal width of unloading passageway, feedstock channel 7 up extends to connecting block 3 and becomes feed inlet 13, threaded connection has the first sealed lid 15 that is used for sealed feed inlet 13 on connecting block 3, unloading passageway 10 down extends to connecting block 3 and becomes discharge gate 14, threaded connection has the sealed lid 16 of second that is used for sealed discharge gate 14 on connecting block 3.

One molecular sieve 8 is arranged in the drainage channel 4, three molecular sieves 8 are arranged in the feeding channel 7, the molecular sieves 8 can slide up and down in the feeding channel 7, and four molecular sieves 8 are stacked together; as shown in fig. 2, the molecular sieve 8 includes a pipe body 23, a plurality of zeolites 25 disposed in the pipe body 23, and mesh covers 24 disposed at two ends of the pipe body 23, wherein sealing rings 22 are respectively disposed at two ends of the pipe body 23, the molecular sieve 8 is disposed in the feed channel 7, the sealing rings 22 at two ends are respectively attached to the inner wall of the feed channel 7, so that the water body is not easy to enter the pipe body 23, the molecular sieve 8 in the drain channel 4 is directly connected with the drain pipe 1 of the filter press, the water body can directly pass through the molecular sieve 8, and heavy metal pollutants in the water body can be adsorbed and sealed on the zeolites 25 in the pipe body 23.

A limiting part 9 is further arranged in the drainage channel 4, the limiting part 9 comprises a ring body 12 and a spring 11, the ring body 12 is in threaded connection with the drainage channel 4, one end of the spring 11 is fixed on the ring body 12, the other end of the spring abuts against the molecular sieve 8, when heavy metal pollutants adsorbed by the molecular sieve 8 in the drainage channel 4 gradually increase, the water flow in the drainage channel 4 becomes slow, the acting force acting on the molecular sieve 8 gradually increases, so that the lowermost molecular sieve 8 gradually moves backwards, when the lowermost molecular sieve 8 is completely moved away from the lower part of the second molecular sieve 8, the second molecular sieve 8 falls into the drainage channel 4, the lowermost molecular sieve 8 is still in the drainage channel 4, when the amount of the solid heavy metal pollutants continues to increase, the water body pushes the two molecular sieves 8 to move backwards together, and when the rear molecular sieve 8 is positioned above the lower channel, the molecular sieve 8 can fall into the blanking channel 10 under the action of self gravity, and the automatic replacement of the molecular sieve 8 is realized by the circulation.

A first slot 17 communicated with the feeding channel 7 is formed in the side wall of the connecting block 3, the first slot 17 is arranged close to the drainage channel 4, a first sealing plate 18 is inserted into the first slot 17, and the first sealing plate 18 can seal the feeding channel 7 after being inserted into the feeding channel 7 through the first slot 17, so that a new molecular sieve 8 can be added into the feeding channel 7 in the drainage process; offer the second slot 19 that is linked together with unloading passageway 10 on the lateral wall of connecting block 3, second slot 19 is close to drainage channel 4 and sets up, the interpolation of second slot 19 is equipped with second closing plate 20, second closing plate 20 can seal unloading passageway 10 after inserting unloading passageway 10 in through second slot 19, thereby can just open the sealed lid 16 of second at the in-process of drainage, make the molecular sieve 8 in the unloading passageway 10 drop, inner at first closing plate 18 and second closing plate 20 is equipped with stopper 21 respectively, the thickness of stopper 21 all is greater than the thickness of first closing plate 18 and second closing plate 20, stopper 21 passes through the bolt and is connected with first closing plate 18 and second closing plate 20.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims

1. The soil remediation process is characterized by comprising the following steps:

s4, water treatment, wherein a molecular sieve mechanism (2) is arranged on a drain pipe (1) of a filter press, and when a water body filtered by the filter press passes through the molecular sieve mechanism (2), heavy metal pollutants are adsorbed and fixedly sealed in the molecular sieve mechanism (2); the molecular sieve mechanism (2) comprises a connecting block (3) connected with a drain pipe (1) of the filter press, the connecting block (3) is provided with a drain channel (4) with two ends penetrating through, one end of the drain channel (4) is a water inlet (5), the other end of the drain channel is a water outlet (6), the drain channel (4) is horizontally and transversely arranged, the drain channel (4) is communicated with the drain pipe (1) of the filter press, the connecting block (3) is provided with a feed channel (7) mutually communicated with the drain channel (4), the feed channel (7) is vertically arranged and positioned above the drain channel (4), the feed channel (7) is internally provided with a plurality of stacked molecular sieves (8) in a vertical sliding manner, the lowermost molecular sieve (8) is positioned in the drain channel (4), and a limiting piece (9) for blocking the molecular sieve (8) is connected with the drain channel (4) on one side opposite to the water outlet (6) through internal threads, the outer wall of a molecular sieve (8) in the drainage channel (4) is in clearance fit with the inner wall of the drainage channel (4), the connecting block (3) is provided with a blanking channel (10) communicated with the drainage channel (4), the blanking channel (10) is vertically arranged and located below the drainage channel (4), the feeding channel (7) and the blanking channel (10) are arranged in a left-right staggered mode, the feeding channel (7) is arranged close to one side of the water inlet (5), the blanking channel (10) is arranged close to one side of the water outlet (6), the limiting part (9) comprises a spring (11) and a ring body (12) in threaded connection with the inner wall of the drainage channel (4), one end of the spring (11) is abutted against the molecular sieve (8) in the drainage channel (4), and the other end of the spring is connected with the ring body (12);

2. A soil remediation process according to claim 1 wherein: and (4) detecting the metal content of the soil in the S5, if the soil passes the detection, transporting the soil to a specified site through a muck truck for recycling, and if the metal content exceeds the standard, re-conveying the soil exceeding the standard into the screening machine.

3. A soil remediation process according to claim 2 wherein: and discharging the water treated in the S4 into a water storage tank, wherein the water in the water storage tank is adopted as the high-pressure water in the S2.

4. A soil remediation process according to claim 3 wherein: the horizontal transverse distance between the central axis of the feeding channel (7) and the central axis of the blanking channel (10) is more than half of the sum of the horizontal width of the feeding channel (7) and the horizontal width of the blanking channel (10).

5. A soil remediation process according to claim 4 wherein: feed channel (7) up extend to connecting block (3) appearance and form feed inlet (13), unloading passageway (10) down extend to connecting block (3) appearance and form discharge gate (14), connecting block (3) threaded connection has first sealed lid (15) that are used for sealed feed inlet (13), connecting block (3) threaded connection has second sealed lid (16) that are used for sealed discharge gate (14).

6. A soil remediation process according to claim 5 wherein: the utility model discloses a drainage channel, including connecting block (3), connecting block (3) lateral wall, first slot (17) that feed channel (7) communicate are equipped with, be provided with first closing plate (18) that are used for sealed feed channel (7) in the slot with sliding, first closing plate (18) outer wall and first slot (17) inner wall seal cooperation, connecting block (3) lateral wall is equipped with second slot (19) that communicate with discharging channel, be provided with second closing plate (20) that are used for sealed discharging channel in the slot with sliding, second closing plate (20) outer wall and second slot (19) inner wall seal cooperation, first slot (17) and second slot (19) all are close to drainage channel (4) and set up.

7. A soil remediation process according to claim 6 wherein: the inner end of the first sealing plate (18) and the inner end of the second sealing plate (20) are both provided with limiting blocks (21), and the thickness of the first sealing plate (18) and the thickness of the second sealing plate (20) are both smaller than the thickness of the limiting blocks (21).