A two-stage iron-carbon micro-electrolysis device and method for sewage treatment

Abstract

A two-stage iron-carbon micro-electrolysis device and method for sewage treatment, relating to the technical field of water pollution control, the two-stage iron-carbon micro-electrolysis device comprises an adsorption reactor, a regeneration reaction liquid filling and recovery system and an aeration system, the water outlet of the upstream water pool is connected to the water inlet of the adsorption reactor, an activated carbon bed is provided in the middle of the adsorption reactor, and a sponge iron bed layer is provided at the bottom, the pollutants contained in the wastewater to be treated are adsorbed and enriched on the activated carbon bed, and the treated wastewater flows into the downstream water pool through the water outlet of the adsorption reactor. Compared with the traditional iron-carbon micro-electrolysis, the two-stage iron-carbon micro-electrolysis of the present invention can solve the problem of easy hardening of iron-carbon fillers by making iron and carbon intermittently contact. The residual acid in the reaction solution and the residual iron can be recovered for the next round of micro-electrolysis reaction. The pollutants can be degraded while the activated carbon is regenerated in the adsorption bed.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution control, and in particular to a two-stage iron-carbon micro-electrolysis device and method for sewage treatment. Background Art

[0002] As people's living standards improve, the production and use of medicines and personal care products increase year by year, and the pollution of difficult-to-degrade micropollutants in water bodies becomes more and more serious, requiring a simple, efficient and low-cost treatment process. The most similar implementation schemes to this technology are as follows:

[0003] Traditional iron-carbon micro-electrolysis technology is an environmentally friendly and resource-saving wastewater oxidation method. There is a significant redox potential difference between carbon and pure iron. Pure iron is used as the anode of the primary cell, and carbon is used as the cathode of the primary cell to form many tiny primary cells. Under anaerobic conditions, the products generated by the cathode electrode reaction (such as new ecological reduced hydrogen [H]) are highly active. Under acidic conditions, hydrogen peroxide can be produced at the cathode. Hydrogen peroxide is not only highly active, but can also form Fenton reagents with divalent iron ions produced by subsequent anode corrosion to produce more free radicals. The primary cell reaction of iron-carbon fillers can undergo redox reactions with various organic components in wastewater, change the structure and characteristics of organic matter in wastewater, and cause chain breaking and ring opening. However, there are problems such as the filler being easy to harden, a large amount of acid and alkali being wasted during operation, and a large amount of salt pollutants being introduced.

[0004] Fixed bed activated carbon adsorption technology, adsorption separation is a method that is efficient, simple to operate, and not prone to producing toxic byproducts. It is considered a practical method for removing micro-pollutants from water, but it cannot degrade pollution, it can only transfer pollutants. Elution regeneration cannot degrade pollutants, and other processes are needed to degrade pollutants.

[0005] There are two major problems with the existing iron-carbon micro-electrolysis technology:

[0006] One is the problem of easy agglomeration of iron-carbon particles and surface passivation of iron filings. After a long period of operation, the iron-carbon micro-electrolysis device is prone to agglomeration of iron filings and carbon particles due to the precipitation of trivalent iron, which reduces the effect. The higher the iron-carbon micro-electrolysis filler device, the more obvious the agglomeration effect. Iron-carbon micro-electrolysis technology can only work under acidic conditions, so a large amount of acid needs to be added when treating non-acidic wastewater, and then a certain amount of alkali needs to be added back. The two phases are superimposed, and a large amount of salt substances are introduced into the wastewater to be treated. On the one hand, the inorganic salts in high-salt wastewater have a strong inhibitory effect on microorganisms; on the other hand, the use of a large amount of acid and alkali to adjust the pH when using the iron-carbon micro-electrolysis process to treat low-concentration wastewater will increase the treatment cost.

[0007] Second, the activated carbon required by existing activated carbon adsorption technology has a limited lifespan and requires frequent regeneration. Moreover, elution regeneration cannot degrade pollutants and other processes are needed to degrade the pollutants. Summary of the invention

[0008] In order to solve the above two major problems of the existing iron-carbon micro-electrolysis technology, the present invention provides a two-stage iron-carbon micro-electrolysis device and method for sewage treatment. The following technical solutions are adopted:

[0009] A two-stage iron-carbon micro-electrolysis device for sewage treatment comprises an upstream water pool and a downstream water pool, wherein the upstream water pool stores wastewater to be treated, and the downstream water pool stores treated wastewater, wherein the two-stage iron-carbon micro-electrolysis device comprises an adsorption reactor, a regeneration reaction liquid filling and recovery system, and an aeration system, wherein the water outlet of the upstream water pool is connected to the water inlet of the adsorption reactor, an activated carbon bed is arranged in the middle of the adsorption reactor, and a sponge iron bed layer is arranged at the bottom, wherein pollutants contained in the wastewater to be treated are adsorbed and enriched on the activated carbon bed, and the treated wastewater flows into the downstream water pool through the water outlet of the adsorption reactor;

[0010] When it is determined that pollutants in the wastewater to be treated have penetrated the activated carbon bed, the water inlet and outlet of the adsorption reactor are closed, the activated carbon bed stops adsorption, and the remaining wastewater to be treated in the activated carbon bed flows from the return water port of the adsorption reactor to the upstream water pool;

[0011] When all the remaining wastewater is completely drained, the regeneration reaction liquid filling and recovery system adds the regeneration reaction liquid to the top of the activated carbon bed of the adsorption reactor, and the aeration system injects high-speed gas into the sponge iron bed. The high-speed airflow carries the sponge iron filter material of the sponge iron bed into the activated carbon bed, where it is fully in contact with the activated carbon bed, and an iron-carbon micro-electrolysis reaction occurs, thereby fully degrading the pollutants enriched on the activated carbon.

[0012] Through the above technical solution, two-stage iron-carbon micro-electrolysis is used to treat the untreated wastewater stored in the upstream pool;

[0013] One section refers to the enrichment and adsorption of pollutants in the wastewater to be treated by the activated carbon bed.

[0014] The second stage refers to when there are pollutants penetrating the activated carbon bed, which means that the activated carbon activity of the activated carbon bed decreases and needs to be regenerated.

[0015] The regeneration reaction liquid filling and recovery system fills the regeneration reaction liquid into the top of the activated carbon bed of the adsorption reactor, and the aeration system injects high-speed gas into the sponge iron bed layer. The high-speed airflow carries the sponge iron filter material of the sponge iron bed layer into the activated carbon bed layer, where it fully contacts with the activated carbon bed, and an iron-carbon micro-electrolysis reaction occurs, thereby fully degrading the pollutants enriched on the activated carbon and completing the regeneration of the activated carbon. The sewage treatment can be carried out repeatedly, and the pH value is not directly adjusted in the wastewater to be treated, thereby avoiding the introduction of salt pollutants into the wastewater to be treated to affect subsequent biochemical reactions. The sponge iron filter material and the activated carbon filter material only contact each other in the iron-carbon micro-electrolysis reaction stage, thereby reducing the possibility of the filter material being compacted.

[0016] Optionally, the adsorption reactor includes an outer shell, an inner tank and a water distribution device. The outer shell is provided with a water inlet at the top, a water outlet, an aeration port and a sponge iron bed at the bottom, the water inlet is connected with the water outlet of an upstream water tank through an inlet valve and a pipeline, and the water outlet is connected with the water inlet of a downstream water tank through an outlet valve and a pipeline. The inner tank is arranged in the central area of ​​the outer shell, and an activated carbon bed is arranged in the inner tank. An air, water and iron ascending channel is formed between the outer shell and the inner tank. The water distribution device is arranged at the top of the outer shell, below the water inlet and above the activated carbon bed, so that the wastewater to be treated entering the water inlet enters the activated carbon bed evenly.

[0017] Through the above technical scheme, a double-layer adsorption reactor structure is adopted, and the inner tank is arranged in the inner central area of ​​the outer shell. The gas, water and iron rising channel can provide an rising channel for the sponge iron filter material entrained by the high-speed airflow when the aeration system is working. After the sponge iron filter material is fully contacted and reacted with the activated carbon in the activated carbon bed, it can fall back to the sponge iron bed layer at the bottom for easy recycling.

[0018] Optionally, the adsorption reactor further comprises a porous folded plate, the upper convex top and the lower concave top of the porous folded plate are both provided with a plurality of holes, the holes are used to pass the sponge iron particles, the porous folded plate is arranged on the inner wall of the inner tank and is located below the activated carbon bed.

[0019] Through the above technical solution, the porous folded plate has holes on the convex top and concave top of the folded plate for allowing iron particles to pass through. The porous folded plate can achieve gas-solid-liquid three-phase flow separation, and gas-solid-liquid convection can be achieved to ensure the full progress of the reaction.

[0020] Optionally, the adsorption reactor also includes a mud discharge system, which includes a mud hopper and a mud discharge valve. The mud hopper is arranged at the bottom of the shell, and a mud discharge hole is arranged at the bottom of the mud hopper. A screen is arranged at the mud discharge hole, and the screen is used to prevent sponge iron particles of normal particle size from passing through. The mud discharge valve is arranged at the bottom of the mud hopper.

[0021] Through the above technical solution, the reaction may produce iron sludge formed by iron scraps and activated carbon powder, which can enter the mud bucket through the mud discharge hole to become bottom mud. When the iron sludge accumulates to a certain extent in the mud bucket, the mud discharge valve can be opened to discharge it.

[0022] Optionally, an overflow weir is formed at the top of the inner tank. When the high-speed airflow carries the water flow to carry the sponge iron filter material of the sponge iron bed layer through the air-water-iron rising channel to the overflow weir, it falls over the overflow weir onto the activated carbon bed.

[0023] Through the above technical scheme, the high-speed airflow entrains the water flow to bring the sponge iron filter material into the outer ring air-water-iron ascending channel to form an iron-containing air-water flow; after the iron-containing air-water flow reaches the overflow weir, the air is discharged from the upper end, and the water and solid sponge iron overflow into the activated carbon bed through the upper overflow weir.

[0024] Optionally, the regeneration reaction liquid filling and recovery system includes a regeneration reaction liquid recovery temporary storage tank, a reaction liquid filling valve, a water and air distribution device, a return water pump, a return water valve, a reaction liquid return water valve and an upstream return water valve. The liquid outlet of the regeneration reaction liquid recovery temporary storage tank is connected to the water inlet at the top of the adsorption reactor through the reaction liquid filling valve and a pipeline. The water and air distribution device is arranged below the activated carbon bed, and the water and air distribution holes are facing the activated carbon bed. The adsorption reactor is provided with a return water port, which is connected to the liquid inlet of the regeneration reaction liquid recovery temporary storage tank through the return water pump and the reaction liquid return water valve. The return water port is connected to the upstream water tank through the return water valve, the return water pump and the upstream return water valve in sequence.

[0025] Through the above technical scheme, the regeneration reaction liquid recovery temporary storage tank is used to store the regeneration reaction liquid. When the activated carbon in the activated carbon bed needs to be regenerated, the reaction liquid filling valve is opened to add the regeneration reaction liquid to the activated carbon bed. When the regeneration process is completed, the reaction liquid return valve and the return pump are opened, and the return pump recovers the regeneration liquid to the regeneration reaction liquid recovery temporary storage tank.

[0026] Optionally, the aeration system includes surrounding blowers, surrounding air inlet valves, a central blower and a central air inlet valve. A jet hole is provided at the bottom of the adsorption reactor. The air outlets of the surrounding blowers are connected to the jet holes through the surrounding air inlet valves and pipelines, and high-speed airflow is sprayed toward the sponge iron bed. The central blower is connected to the return water outlet of the adsorption reactor through the central air inlet valve and pipeline, and sprays high-speed airflow toward the activated carbon bed through the water and air distribution device.

[0027] Through the above technical scheme, two blowers are arranged in the aeration system. A high-speed airflow ejected from the blowers on all sides enters from the jet holes at the bottom of the adsorption reactor in order to blow the sponge iron filter material in the sponge iron bed upward from the air-water-iron rising channel. The high-speed airflow ejected from the central blower is sprayed onto the activated carbon bed through the water and air distribution device, which provides oxidation conditions for the reaction while slightly expanding the activated carbon filter material, so that the sponge iron and activated carbon have a filter material grading effect, thereby separating the sponge iron and activated carbon.

[0028] Optionally, the particle size of activated carbon particles in the activated carbon bed is greater than 4 mm, and the particle size of sponge iron filter material particles in the sponge iron bed is greater than 1.5 mm and less than 2 mm.

[0029] Through the above technical solution, the particle size of activated carbon particles is above 4 mm, or honeycomb regular activated carbon is used, which is filled in the activated carbon bed and will not be lost from the perforated folding plate under the activated carbon bed during the regeneration and adsorption process;

[0030] The sponge iron particles have a particle size of more than 1.5 mm and less than 2 mm. They are installed at the bottom of the outer ring and can freely pass through the perforated folding plate below the activated carbon bed, but cannot pass through the jet channel and mud discharge hole when not reacted.

[0031] A two-stage iron-carbon micro-electrolysis method, the specific method is:

[0032] Step 1, open the water inlet valve and the water outlet valve, and the wastewater to be treated flows into the water distribution device and then flows evenly into the activated carbon bed, and the pollutants contained are adsorbed and enriched on the activated carbon bed. After treatment, the wastewater flows into the downstream water pool through the suction and discharge valve;

[0033] Step 2: When it is determined that pollutants in the wastewater to be treated have penetrated the activated carbon bed, the water inlet valve and the water outlet valve are closed, the activated carbon bed stops adsorption, the return valve and the return pump are opened, and the remaining wastewater to be treated in the activated carbon bed returns to the upstream pool;

[0034] Step 3, when all the remaining wastewater is completely drained, the reaction liquid filling valve is opened, and the regenerated reaction liquid flows evenly into the activated carbon bed after passing through the water distribution device;

[0035] Step 4, turning on the surrounding blowers and surrounding air inlet valves, the high-speed airflow blown by the surrounding blowers entrains the sponge iron filter material of the sponge iron bed layer to form a sponge iron gas-water flow, which passes through the gas-water-iron ascending channel, over the overflow weir, and falls into the activated carbon bed;

[0036] Open the central blower, the central air inlet valve and the water outlet valve, and the air passes through the central blower, the central air inlet valve, the water outlet valve, the water and air distribution device, and the holes in the upper convex part of the porous folded plate to enter the activated carbon bed in the central reaction zone;

[0037] Step 5, iron-carbon micro-electrolysis reaction, the sponge iron filter material particles come into contact with the activated carbon bed, and an iron-carbon micro-electrolysis reaction occurs, which fully degrades the pollutants enriched on the activated carbon, and gradually passes through the activated carbon bed, falls onto the porous folding plate, and falls back to the sponge iron bed layer at the hole at the concave bottom of the porous folding plate. After the iron-carbon micro-electrolysis reaction is completed, the surrounding blowers and the surrounding air inlet valves are first closed;

[0038] Step 6: After the separation of the sponge iron filter material particles and the activated carbon is completed, the central blower, the central air inlet valve and the water outlet valve are closed, and the return valve, the return pump and the reaction liquid return valve are opened. The reaction liquid in the activated carbon bed is returned to the regeneration reaction liquid recovery temporary storage tank through the water and air distribution device;

[0039] Step 7, close the return valve, return pump, and reaction liquid return valve, and repeat step 1, over and over again.

[0040] Optionally, in step 6, after the sponge iron and activated carbon are separated, the return valve 21, the return pump 22 and the reaction liquid return valve 23 are opened, and the reaction liquid filling valve 10 is opened to further clean the surface of the activated carbon filter material to reduce the effect of the broken sponge iron attached to the surface of the activated carbon on the adsorption. After the cleaning is completed, the reaction liquid filling valve 10 is closed, and the reaction liquid in the activated carbon bed is returned to the regeneration reaction liquid recovery temporary storage tank through the water and gas distribution device.

[0041] In summary, the present invention includes the following beneficial technical effects:

[0042] 1. Compared with the traditional iron-carbon micro-electrolysis, the two-stage iron-carbon micro-electrolysis of the present invention can solve the problem of easy agglomeration of iron-carbon fillers by making iron and carbon contact intermittently.

[0043] Second, because the micro-electrolysis reaction is carried out in the reaction solution after replacement, the residual acid and residual iron in the reaction solution can be recovered and used for the next round of micro-electrolysis reaction. And because no acid and alkali are directly added to the wastewater to be treated, the salinity of the wastewater to be treated is not increased, which is conducive to the subsequent biochemical reaction.

[0044] 3. Compared with traditional fixed bed adsorption, the life of activated carbon is limited and requires frequent regeneration, and elution regeneration cannot degrade pollutants.

[0045] Fourth, the present invention can degrade pollutants while regenerating activated carbon in the adsorption bed. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the structural connection principle of the present invention;

[0047] Figure 2 It is a schematic diagram of the internal structure of the adsorption reactor of the present invention;

[0048] Figure 3 yes Figure 2 A local enlarged structural diagram of region A;

[0049] Figure 4 yes Figure 2 BB cross-sectional structural diagram;

[0050] Figure 5 yes Figure 2 Schematic diagram of CC cross-sectional structure;

[0051] Figure 6 yes Figure 2 DD cross-sectional structure schematic diagram.

[0052] Explanation of the reference numerals in the accompanying drawings: 1. upstream water tank; 8. downstream water tank; 3. water distribution device; 4. activated carbon bed; 17. sponge iron bed layer; 31. outer shell; 32. liner; 18. gas, water and iron ascending channel; 5. porous folding plate; 20. mud discharge hole; 26. mud discharge valve; 27. mud bucket; 28. overflow weir; 9. regeneration reaction liquid recovery temporary storage tank; 10. reaction liquid filling valve; 6. water and air distribution device; 7. water outlet valve; 22. return water pump; 21. return water valve; 23. reaction liquid return water valve; 11. surrounding blowers; 12. surrounding air intake valves; 13. central blower; 14. central air intake valve; 15. air distribution channel; 16. jet hole; 24. upstream return water valve; 19. sponge iron return channel. DETAILED DESCRIPTION

[0053] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0054] The embodiment of the invention discloses a two-stage iron-carbon micro-electrolysis device and method for sewage treatment.

[0055] Reference Figure 1-Figure 6 A two-stage iron-carbon micro-electrolysis device for sewage treatment comprises an upstream water pool 1 and a downstream water pool 8, wherein the upstream water pool 1 stores wastewater to be treated, and the downstream water pool 8 stores treated wastewater, wherein the two-stage iron-carbon micro-electrolysis device comprises an adsorption reactor, a regeneration reaction liquid filling and recovery system, and an aeration system, wherein the water outlet of the upstream water pool 1 is connected to the water inlet of the adsorption reactor, an activated carbon bed 4 is provided in the middle of the adsorption reactor, and a sponge iron bed layer 17 is provided at the bottom, wherein pollutants contained in the wastewater to be treated are adsorbed and enriched on the activated carbon bed 4, and the treated wastewater flows into the downstream water pool 8 through the water outlet of the adsorption reactor;

[0056] When it is determined that there are pollutants in the wastewater to be treated that penetrate the activated carbon bed 4, the water inlet and outlet of the adsorption reactor are closed, the activated carbon bed 4 stops adsorption, and the remaining wastewater to be treated in the activated carbon bed 4 flows from the return water port of the adsorption reactor to the upstream water pool 1;

[0057] When all the remaining wastewater is completely drained, the regeneration reaction liquid filling and recovery system adds the regeneration reaction liquid to the top of the activated carbon bed 4 of the adsorption reactor, and the aeration system injects high-speed gas into the sponge iron bed layer 17. The high-speed airflow carries the sponge iron filter material of the sponge iron bed layer 17 into the activated carbon bed 4 layer, where it fully contacts with the activated carbon bed 4, and an iron-carbon micro-electrolysis reaction occurs, thereby fully degrading the pollutants enriched on the activated carbon.

[0058] A two-stage iron-carbon micro-electrolysis is used to treat the untreated wastewater stored in the upstream pool 1;

[0059] One section refers to the activated carbon bed 4 which enriches and adsorbs the pollutants in the wastewater to be treated.

[0060] The second stage means that when pollutants penetrate the activated carbon bed 4, it means that the activated carbon activity of the activated carbon bed 4 is reduced and needs to be regenerated. A comprehensive water quality online detector or a COD online detector is installed before the downstream water pool. When the pollutant concentration is detected to exceed the preset value, it means that the pollutants have penetrated the activated carbon bed 4.

[0061] The regeneration reaction liquid filling and recovery system fills the regeneration reaction liquid into the top of the activated carbon bed 4 of the adsorption reactor, and the aeration system injects high-speed gas into the sponge iron bed layer 17. The high-speed airflow carries the sponge iron filter material of the sponge iron bed layer 17 into the activated carbon bed 4 layer, and fully contacts with the activated carbon bed 4, so that an iron-carbon micro-electrolysis reaction occurs, and the pollutants enriched on the activated carbon are fully degraded, and the regeneration of the activated carbon is completed. The sewage treatment can be carried out repeatedly, and the pH value is not directly adjusted in the wastewater to be treated, thereby avoiding the introduction of salt pollutants into the wastewater to be treated to affect subsequent biochemical reactions. The sponge iron filter material and the activated carbon filter material are in contact with each other only in the iron-carbon micro-electrolysis reaction stage, thereby reducing the possibility of the filter material being compacted.

[0062] The adsorption reactor includes an outer shell 31, an inner shell 32 and a water distribution device 3. The outer shell 31 is provided with a water inlet at the top, a water outlet, an aeration port and a sponge iron bed 17 at the bottom. The water inlet is connected with the water outlet of the upstream water tank 1 through an inlet valve 2 and a pipeline, and the water outlet is connected with the water inlet of the downstream water tank 8 through an outlet valve 7 and a pipeline. The inner shell 32 is arranged in the central area of ​​the outer shell 31, and an activated carbon bed 4 is arranged in the inner shell 32. An air, water and iron ascending channel 18 is formed between the outer shell 31 and the inner shell 32. The water distribution device 3 is arranged at the top of the outer shell 31, below the water inlet and above the activated carbon bed 4, so that the wastewater to be treated entering the water inlet can enter the activated carbon bed 4 evenly.

[0063] A double-layer adsorption reactor structure is adopted, and the inner tank 32 is arranged in the inner central area of ​​the outer shell 31. The air, water and iron ascending channel 18 can provide an ascending channel for the sponge iron filter material entrained by the high-speed airflow when the aeration system is working. After the sponge iron filter material fully contacts and reacts with the activated carbon in the activated carbon bed 4, it can fall back to the sponge iron bed layer 17 at the bottom for easy recycling.

[0064] The adsorption reactor also includes a porous folded plate 5 , the upper convex top and the lower concave top of the porous folded plate 5 are both provided with a plurality of holes for passing the sponge iron particles. The porous folded plate 5 is arranged on the inner wall of the inner tank 32 and is located below the activated carbon bed 4 .

[0065] The porous folded plate 5 has holes at the convex top and concave top of the folded plate for allowing iron particles to pass through. The porous folded plate 5 can achieve gas-solid-liquid three-phase flow separation, and gas-solid-liquid convection to each other, ensuring the full progress of the reaction.

[0066] The adsorption reactor also includes a mud discharge system, which includes a mud hopper 27 and a mud discharge valve 26. The mud hopper 27 is arranged at the bottom of the shell 31. A mud discharge hole 20 is arranged at the bottom of the mud hopper 27. A screen is arranged at the mud discharge hole 20. The screen is used to prevent sponge iron particles of normal particle size from passing through. The mud discharge valve 26 is arranged at the bottom of the mud hopper 27.

[0067] The reaction may produce iron mud formed by iron scraps and activated carbon powder, which can enter the mud bucket 27 through the mud discharge hole 20 to become bottom mud. After the iron mud accumulates to a certain extent in the mud bucket 27, the mud discharge valve 26 can be opened to discharge it.

[0068] An overflow weir 28 is formed at the top of the inner tank 32. When the high-speed airflow carries the water flow to carry the sponge iron filter material of the sponge iron bed layer 17 through the air-water-iron ascending channel 18 to the overflow weir 28, it falls over the overflow weir 28 onto the activated carbon bed 4.

[0069] The high-speed airflow carries the water flow and brings the sponge iron filter material into the outer ring air-water-iron ascending channel 18, forming an iron-containing air-water flow; after the iron-containing air-water flow reaches the overflow weir, the air is discharged from the upper end, and the water and solid sponge iron overflow into the activated carbon bed 4 through the upper overflow weir 28.

[0070] The regeneration reaction liquid filling and recovery system includes a regeneration reaction liquid recovery temporary storage tank 9, a reaction liquid filling valve 10, a water and air distribution device 6, a return water pump 22, a return water valve 21, a reaction liquid return water valve 23 and an upstream return water valve 24. The liquid outlet of the regeneration reaction liquid recovery temporary storage tank 9 is connected to the water inlet at the top of the adsorption reactor through the reaction liquid filling valve 10 and a pipeline. The water and air distribution device 6 is arranged below the activated carbon bed 4, and the water and air distribution holes are facing the activated carbon bed 4. The adsorption reactor is provided with a return water port, which is connected to the liquid inlet of the regeneration reaction liquid recovery temporary storage tank 9 through the return water pump 22 and the reaction liquid return water valve 23. The return water port is connected to the upstream water tank 1 through the return water valve 21, the return water pump 22 and the upstream return water valve 24 in sequence.

[0071] The regeneration reaction liquid recovery temporary storage tank 9 is used to store the regeneration reaction liquid. When the activated carbon in the activated carbon bed 4 needs to be regenerated, the reaction liquid filling valve 10 is opened to add the regeneration reaction liquid to the activated carbon bed 4. When the regeneration process is completed, the reaction liquid return valve 23 and the return pump 22 are opened, and the return pump 22 recovers the regeneration liquid to the regeneration reaction liquid recovery temporary storage tank 9.

[0072] The aeration system includes a surrounding blower 11, a surrounding air inlet valve 12, a central blower 13 and a central air inlet valve 14. A jet hole 16 is provided at the bottom of the adsorption reactor. The air outlet of the surrounding blower 11 is connected with the jet hole 16 through the surrounding air inlet valve 12 and a pipeline, and a high-speed airflow is sprayed toward the sponge iron bed 17. The central blower 13 is connected with the return water outlet of the adsorption reactor through the central air inlet valve 14 and a pipeline, and a high-speed airflow is sprayed toward the activated carbon bed 4 through the water and air distribution device 6.

[0073] The aeration system is equipped with two blowers. A high-speed airflow ejected from the peripheral blowers 11 enters from the jet hole 1 at the bottom of the adsorption reactor in order to blow the sponge iron filter material in the sponge iron bed 17 upward from the air-water-iron rising channel 18. The high-speed airflow ejected from the central blower 13 is sprayed toward the activated carbon bed 4 through the water and air distribution device 6, which provides oxidation conditions for the reaction while slightly expanding the activated carbon filter material, so that the sponge iron and activated carbon have a filter material grading effect, thereby separating the sponge iron and activated carbon.

[0074] The particle size of the activated carbon particles of the activated carbon bed 4 is greater than 4 mm, and the particle size of the sponge iron filter material particles of the sponge iron bed layer 17 is greater than 1.5 mm and less than 2 mm.

[0075] The activated carbon particles have a particle size of more than 4 mm, or honeycomb-shaped regular activated carbon is used, which is filled in the activated carbon bed 4 and will not be lost from the perforated folding plate 5 below the activated carbon bed 4 during the regeneration and adsorption process;

[0076] The sponge iron particles have a particle size of more than 1.5 mm and less than 2 mm, and are installed at the bottom of the outer ring. They can freely pass through the perforated folding plate 5 below the activated carbon bed 4, but cannot pass through the jet channel 16 and the mud discharge hole 20 when they are not reacted.

[0077] A two-stage iron-carbon micro-electrolysis method, the specific method is:

[0078] Step 1, open the water inlet valve 2 and the water outlet valve 7, the wastewater to be treated flows into the water distribution device 3 and then flows evenly into the activated carbon bed 4, the pollutants contained are adsorbed and enriched on the activated carbon bed 4, and the treated wastewater flows into the downstream water pool 8 through the suction and outlet valve 7;

[0079] Step 2, when it is determined that pollutants in the wastewater to be treated have penetrated the activated carbon bed 4, the water inlet valve 2 and the water outlet valve 7 are closed, the activated carbon bed 4 stops adsorption, the return valve 21 and the return pump 22 are opened, and the remaining wastewater to be treated in the activated carbon bed 4 returns to the upstream pool 1;

[0080] Step 3, when all the remaining wastewater is completely drained, the reaction liquid filling valve 10 is opened, and the regenerated reaction liquid flows evenly into the activated carbon bed 4 after passing through the water distribution device 3;

[0081] Step 4, open the surrounding blowers 11 and the surrounding air inlet valves 12, and the high-speed airflow blown by the surrounding blowers 11 entrains the sponge iron filter material in the sponge iron bed layer 17 to form a sponge iron gas-water flow, which passes through the gas-water-iron ascending channel 18, over the overflow weir 28, and falls into the activated carbon bed 4;

[0082] The central blower 13, the central air inlet valve 14 and the water outlet valve 7 are turned on, and the air enters the activated carbon bed in the central reaction zone through the central blower 13, the central air inlet valve 14, the water outlet valve 7, the water and air distribution device 6, and the holes in the upper convex part of the porous folded plate 5;

[0083] Step 5, iron-carbon micro-electrolysis reaction, the sponge iron filter material particles come into contact with the activated carbon bed 4, and an iron-carbon micro-electrolysis reaction occurs, which fully degrades the pollutants enriched on the activated carbon, and gradually passes through the activated carbon bed 4, falls onto the porous folding plate 5, and falls back to the sponge iron bed layer 17 at the hole at the concave bottom end of the porous folding plate 5. After the iron-carbon micro-electrolysis reaction is completed, the surrounding blowers 11 and the surrounding air inlet valves 12 are first closed;

[0084] Step 6, after the separation of the sponge iron filter material particles and the activated carbon is completed, the central blower 13, the central air inlet valve 14 and the water outlet valve 7 are closed, the return valve 21, the return pump 22 and the reaction liquid return valve 23 are opened, and the reaction liquid in the activated carbon bed 4 is returned to the regeneration reaction liquid recovery temporary storage tank 9 through the water and air distribution device 6;

[0085] In step 6, after the sponge iron and activated carbon are separated, the return valve 21, the return pump 22 and the reaction liquid return valve 23 are opened, and the reaction liquid filling valve 10 is opened to further clean the surface of the activated carbon filter material to reduce the influence of the broken sponge iron attached to the surface of the activated carbon on the adsorption. After the cleaning is completed, the reaction liquid filling valve 10 is closed again, and the reaction liquid in the activated carbon bed is returned to the regeneration reaction liquid recovery temporary storage tank through the water and gas distribution device;

[0086] Step 7, close the return valve 21, the return pump 22, and the reaction liquid return valve 23, and repeat step 1, in a reciprocating cycle.

[0087] The present invention is a two-stage iron-carbon micro-electrolysis device and method for sewage treatment. Specific implementation principle:

[0088] 1) Open the water inlet valve 2 and the water outlet valve 7, and the wastewater to be treated passes through the water inlet valve 2 and the upper water distribution device 3 and enters the activated carbon bed 4.

[0089] 2) The pollutants contained in the wastewater to be treated are adsorbed and enriched on the activated carbon bed 4 in the central reaction adsorption tank of the reaction device. The pollutants are intercepted by the carbon bed 4. The wastewater after adsorption passes through the folded plate orifice 5 and directly enters the lower water and air distribution device 6 from the water and air distribution holes. Finally, the treated wastewater enters the downstream water tank through the outlet valve 7.

[0090] 3) When the pollutants in the wastewater to be treated penetrate the activated carbon bed 4, close the outlet valve 7 and the inlet valve 2 to stop the water inlet and adsorption. Open the return valve 21, the return pump 22, and the upstream return valve 24, and the remaining wastewater to be treated in the activated carbon bed will be discharged from the reaction device through the return valve and returned to the upstream water tank 1.

[0091] 4) After all the remaining wastewater in the reaction device is drained, close the return valve 21, the return pump 22, and the upstream return valve 24. Open the reaction liquid filling valve 10, and the acidic (pH=3) reaction liquid enters the reaction device from the regeneration reaction liquid recovery temporary storage tank 9.

[0092] 5) The reaction liquid filling system is closed, and the surrounding blowers 11 and the surrounding air inlet valves 12 are opened. The high-pressure airflow enters the air distribution channel 15, passes through the jet hole 16, and enters the sponge iron bed layer 17 at high speed. The high-speed airflow carries the water flow to bring the sponge iron filter material into the outer ring air, water and iron ascending channel 18, forming an iron-containing gas-water flow; after the iron-containing gas-water flow reaches the overflow weir, the air is discharged from the upper end, and the water and solid sponge iron overflow into the activated carbon bed 4 through the upper overflow weir 28. Then the central blower 13, the central air inlet valve 14, and the water outlet valve 7 are opened, and the air passes through the central blower 13, the central air inlet valve 14, the water outlet valve 7, the water and air distribution device 6, and the holes of the upper convex part of the porous folding plate 5 to enter the activated carbon bed in the central reaction area, providing oxidation conditions for the reaction while slightly expanding the activated carbon filter material, so that the sponge iron and activated carbon have a filter material classification effect, and the sponge iron and activated carbon are separated. The sponge iron particles are in full contact with the activated carbon bed 4 in the central reaction adsorption tank, and an iron-carbon micro-electrolysis reaction occurs, which fully degrades the pollutants enriched in the activated carbon; under the action of filter material grading, the sponge iron filter material passes through the activated carbon bed, and under the screening and three-phase separation of the porous folding plate 5, the sponge iron filter material passes through the holes in the concave part of the porous folding plate 5, and returns to the sponge iron bed layer through the sponge iron reflux channel 19, and then forms an iron-containing gas-water flow again under the influence of the high-speed airflow, and the cycle repeats.

[0093] 6) After the iron-carbon micro-electrolysis reaction is completed, close the surrounding air inlet valves 12 and the surrounding high-pressure blowers 11, adjust the central air inlet valve 14 to a suitable air flow rate, and rely on air to form filter material grading to completely separate the sponge iron and activated carbon. The activated carbon has a small density and a high expansion degree, and its overall relative increase; the sponge iron has a large density and a small expansion degree, and it relatively decreases. It will pass through the porous folded plate 5 and return to the sponge iron bed through the sponge iron reflux channel 19.

[0094] 7) After the separation of sponge iron and activated carbon is completed, the blower 13, the central air inlet valve 14, and the water outlet valve 7 are closed; the return valve 21, the return pump 22, and the reaction liquid return valve 23 are opened. The reaction liquid in the activated carbon bed is returned to the regeneration reaction liquid recovery temporary storage tank through the water and air distribution device.

[0095] 8) Close the return valve 21, the return pump 22, and the reaction liquid return valve 23, and repeat step 1) for the second cycle.

[0096] 9) The reaction may produce iron sludge formed by iron scraps and activated carbon powder, which can enter the mud bucket 27 through the mud discharge hole 20 to become bottom mud. When the iron sludge accumulates to a certain extent in the mud bucket 27, the mud discharge valve 26 can be opened to discharge it.

[0097] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A two-stage iron-carbon micro-electrolysis device for sewage treatment, comprising an upstream water tank (1) and a downstream water tank (8), wherein the upstream water tank (1) stores wastewater to be treated, and the downstream water tank (8) stores treated wastewater, characterized in that: The two-stage iron-carbon micro-electrolysis device comprises an adsorption reactor, a regeneration reaction liquid filling and recovery system and an aeration system. The water outlet of the upstream water pool (1) is connected to the water inlet of the adsorption reactor. An activated carbon bed (4) is provided in the middle of the adsorption reactor, and a sponge iron bed layer (17) is provided at the bottom. Pollutants contained in the wastewater to be treated are adsorbed and enriched on the activated carbon bed (4), and the treated wastewater flows into the downstream water pool (8) through the water outlet of the adsorption reactor. When it is determined that pollutants in the wastewater to be treated have penetrated the activated carbon bed (4), the water inlet and the water outlet of the adsorption reactor are closed, the activated carbon bed (4) stops adsorption, and the remaining wastewater to be treated in the activated carbon bed (4) flows from the return water outlet of the adsorption reactor to the upstream water pool (1); When all the remaining wastewater is completely drained, the regeneration reaction liquid filling and recovery system fills the regeneration reaction liquid to the top of the activated carbon bed (4) of the adsorption reactor, and the aeration system injects high-speed gas into the sponge iron bed layer (17). The high-speed gas flow entrains the sponge iron filter material of the sponge iron bed layer (17) into the activated carbon bed (4) layer, and the sponge iron filter material is fully contacted with the activated carbon bed (4), and an iron-carbon micro-electrolysis reaction occurs, so that the pollutants enriched on the activated carbon are fully degraded; The adsorption reactor comprises an outer shell (31), an inner shell (32) and a water distribution device (3); the outer shell (31) is provided with a water inlet at the top and a water outlet, an aeration port and a sponge iron bed (17) at the bottom; the water inlet is connected to the water outlet of an upstream water pool (1) through an inlet valve (2) and a pipeline; the water outlet is connected to the water inlet of a downstream water pool (8) through an outlet valve (7) and a pipeline; the inner shell (32) is arranged in the central area of ​​the outer shell (31); an activated carbon bed (4) is arranged in the inner shell (32); an air, water and iron ascending channel (18) is formed between the outer shell (31) and the inner shell (32); the water distribution device (3) is arranged at the top of the outer shell (31), below the water inlet and above the activated carbon bed (4), so that the wastewater to be treated entering the water inlet can enter the activated carbon bed (4) evenly; The adsorption reactor further comprises a porous folded plate (5), wherein the upper convex top and the lower concave top of the porous folded plate (5) are both provided with a plurality of holes, wherein the holes are used to pass sponge iron particles, and the porous folded plate (5) is arranged on the inner wall of the inner tank (32) and is located below the activated carbon bed (4); An overflow weir (28) is formed at the top of the inner tank (32). When the high-speed airflow carries the water flow to carry the sponge iron filter material of the sponge iron bed layer (17) through the air-water-iron ascending channel (18) to the overflow weir (28), the filter material passes over the overflow weir (28) and falls onto the activated carbon bed (4); The aeration system comprises a peripheral blower (11), a peripheral air inlet valve (12), a central blower (13) and a central air inlet valve (14); a jet hole (16) is provided at the bottom of the adsorption reactor; the air outlet of the peripheral blower (11) is connected to the jet hole (16) through the peripheral air inlet valve (12) and a pipeline, and a high-speed airflow is sprayed toward the sponge iron bed (17); the central blower (13) is connected to the water return port of the adsorption reactor through the central air inlet valve (14) and a pipeline, and a high-speed airflow is sprayed toward the activated carbon bed (4) through the water and air distribution device (6).

2. A two-stage iron-carbon micro-electrolysis device for sewage treatment according to claim 1, characterized in that: The adsorption reactor further comprises a mud discharge system, the mud discharge system comprising a mud hopper (27) and a mud discharge valve (26), the mud hopper (27) being arranged at the bottom of the housing (31), a mud discharge hole (20) being arranged at the bottom of the mud hopper (27), a screen being arranged at the mud discharge hole (20), the screen being used to prevent sponge iron particles of normal particle size from passing through, and the mud discharge valve (26) being arranged at the bottom of the mud hopper (27).

3. The two-stage iron-carbon micro-electrolysis device for sewage treatment according to claim 1, characterized in that: The regeneration reaction liquid filling and recovery system comprises a regeneration reaction liquid recovery temporary storage tank (9), a reaction liquid filling valve (10), a water and air distribution device (6), a return water pump (22), a return water valve (21), a reaction liquid return water valve (23) and an upstream return water valve (24). The liquid outlet of the regeneration reaction liquid recovery temporary storage tank (9) is connected to the water inlet at the top of the adsorption reactor through the reaction liquid filling valve (10) and a pipeline. The water and air distribution device (6) is arranged below the activated carbon bed (4), and the water and air distribution holes face the activated carbon bed (4). The adsorption reactor is provided with a return water port. The return water port is connected to the liquid inlet of the regeneration reaction liquid recovery temporary storage tank (9) through the return water pump (22) and the reaction liquid return water valve (23). The return water port is connected to the upstream water tank (1) through the return water valve (21), the return water pump (22) and the upstream return water valve (24) in sequence.

4. A two-stage iron-carbon micro-electrolysis device for sewage treatment according to claim 1, characterized in that: The activated carbon particles of the activated carbon bed (4) have a particle size greater than 4 mm, and the sponge iron filter material particles of the sponge iron bed layer (17) have a particle size greater than 1.5 mm and less than 2 mm.

5. A two-stage iron-carbon micro-electrolysis method, characterized in that: The two-stage iron-carbon micro-electrolysis device for sewage treatment according to any one of claims 1 to 4 is used to carry out two-stage iron-carbon micro-electrolysis, and the specific method is: Step 1, open the water inlet valve (2) and the water outlet valve (7), and the wastewater to be treated flows into the water distribution device (3) and then flows evenly into the activated carbon bed (4), and the pollutants contained in the wastewater are adsorbed and enriched on the activated carbon bed (4). After treatment, the wastewater flows into the downstream water pool (8) through the water suction and discharge valve (7); Step 2, when it is determined that pollutants in the wastewater to be treated have penetrated the activated carbon bed (4), the water inlet valve (2) and the water outlet valve (7) are closed, the activated carbon bed (4) stops adsorption, the return valve (21) and the return pump (22) are opened, and the remaining wastewater to be treated in the activated carbon bed (4) returns to the upstream pool (1); Step 3, when all the remaining wastewater is completely drained, the reaction liquid filling valve (10) is opened, and the regenerated reaction liquid flows evenly into the activated carbon bed (4) after passing through the water distribution device (3); Step 4, opening the surrounding blowers (11) and the surrounding air inlet valves (12), so that the high-speed airflow blown by the surrounding blowers (11) entrains the sponge iron filter material in the sponge iron bed layer (17) to form a sponge iron gas-water flow, which passes through the gas-water-iron ascending channel (18), over the overflow weir (28), and falls into the activated carbon bed (4); The central blower (13), the central air inlet valve (14) and the water outlet valve (7) are opened, and air enters the activated carbon bed in the central reaction zone through the central blower (13), the central air inlet valve (14), the water outlet valve (7), the water and air distribution device (6), and the holes in the upper convex part of the porous folded plate (5); Step 5, iron-carbon micro-electrolysis reaction, the sponge iron filter material particles come into contact with the activated carbon bed (4), and an iron-carbon micro-electrolysis reaction occurs, which fully degrades the pollutants enriched on the activated carbon, and gradually passes through the activated carbon bed (4), falls onto the porous folded plate (5), and falls back to the sponge iron bed layer (17) at the hole at the concave bottom end of the porous folded plate (5). After the iron-carbon micro-electrolysis reaction is completed, the surrounding blowers (11) and the surrounding air inlet valves (12) are first closed; Step 6, after the separation of the sponge iron filter material particles and the activated carbon is completed, the central blower (13), the central air inlet valve (14) and the water outlet valve (7) are closed, the return valve (21), the return pump (22) and the reaction liquid return valve (23) are opened, and the reaction liquid in the activated carbon bed (4) is returned to the regeneration reaction liquid recovery temporary storage tank (9) through the water and air distribution device (6); Step 7, close the return valve (21), the return pump (22), and the reaction liquid return valve (23), and repeat step 1, in a reciprocating cycle.

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