A combined process of double oxidation-electrochemical oxidation for treating landfill leachate

Abstract

The application discloses a kind of dual oxidation-electrochemical oxidation combined process for treating garbage percolate, comprising the following steps: garbage percolate is pretreated, and the pretreated garbage percolate is obtained;Dual oxidation is carried out to the pretreated garbage percolate, filtered, and treatment liquid A is obtained;Porous spherical activated carbon adsorbent is added to treatment liquid A, mixed uniformly, and then treated by blowing, filtered, and treatment liquid B is obtained;Electrochemical oxidation is carried out to treatment liquid B, and then discharged after standing and filtering.The application is used to solve the technical problem of poor garbage percolate treatment effect.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and particularly relates to a combined process of dual oxidation and electrochemical oxidation for treating landfill leachate. Background Technology

[0002] With the acceleration of urbanization and the rapid development of the global economy, the amount of urban waste generated has increased exponentially. Waste incineration and landfill are important means of urban waste disposal. Among them, waste-to-energy incineration can not only efficiently reduce and render harmless waste, but also turn waste into treasure for reuse, thus its application is becoming increasingly widespread. Waste-to-energy incineration requires the storage of large amounts of waste for use. However, during the storage process, organic matter decomposes to produce a certain amount of wastewater. Combined with precipitation and infiltrated groundwater, this water accumulates to form a large amount of leachate.

[0003] Landfill leachate is wastewater containing high concentrations of pollutants generated during the reprocessing of waste at landfills or incinerators. This wastewater typically contains high concentrations of organic matter, ammonia nitrogen, heavy metals, and other toxic and harmful substances, and is characterized by complex water quality, high pollutant concentrations, and difficulty in degradation. Therefore, the treatment of landfill leachate has always been a challenging problem in the environmental protection field.

[0004] Currently, traditional methods for treating landfill leachate commonly employ biological treatment. However, these methods have limitations in reducing COD (Chemical Oxygen Demand). Cr The removal efficiency of ammonia nitrogen is poor, making it difficult to meet emission standards. Summary of the Invention

[0005] This invention provides a combined dual oxidation-electrochemical oxidation process for treating landfill leachate, in order to solve the technical problem of poor treatment effect of current landfill leachate treatment.

[0006] In view of this, the present invention provides a combined oxidation-electrochemical oxidation process for treating landfill leachate, comprising the following steps:

[0007] S1: Pre-treat the landfill leachate to obtain pre-treated landfill leachate;

[0008] S2: The pretreated landfill leachate is subjected to double oxidation treatment, and then filtered to obtain treated liquid A;

[0009] S3: Add porous spherical activated carbon adsorbent to treatment solution A, mix evenly, let stand, then strip and filter to obtain treatment solution B;

[0010] S4: Electrochemically oxidize the treatment solution B, let it stand, filter it, and then discharge it.

[0011] Among them, the porous spherical activated carbon adsorbent is an amination-modified rosin-based adsorption resin.

[0012] Furthermore, a combined oxidation-electrochemical oxidation process for treating landfill leachate includes the following steps:

[0013] S1: Pre-treat the landfill leachate to obtain pre-treated landfill leachate;

[0014] S2: The pretreated landfill leachate is subjected to double oxidation treatment, and then filtered to obtain treated liquid A;

[0015] S3: Add porous spherical activated carbon adsorbent to treatment solution A, mix evenly, let stand for 1-2 hours, then strip for 5-10 minutes, filter, and obtain treatment solution B.

[0016] S4: Electrochemically oxidize the treatment solution B, let it stand, filter it, and then discharge it.

[0017] The porous spherical activated carbon adsorbent is an amination-modified rosin-based adsorption resin; the amount of porous spherical activated carbon adsorbent added in step S3 is 4-8 wt% of the landfill leachate.

[0018] Optionally, the specific steps of the pretreatment in step S1 are as follows: allow the landfill leachate to settle naturally, filter it through a grid, collect the filtrate, and perform oil separation treatment on the filtrate to obtain the pretreated landfill leachate.

[0019] Furthermore, the specific steps of the pretreatment in step S1 are as follows: allow the landfill leachate to settle naturally for 4-6 hours, filter it through a grid, collect the filtrate, and perform oil separation treatment on the filtrate for 60-100 minutes to obtain the pretreated landfill leachate.

[0020] Optionally, the specific steps of the hydrogen peroxide treatment in step S2 are as follows: add hydrogen peroxide to the pretreated landfill leachate, mix evenly, let stand, and simultaneously perform ultraviolet irradiation treatment to induce precipitation.

[0021] Furthermore, the specific steps of the hydrogen peroxide treatment in step S2 are as follows: add hydrogen peroxide to the pretreated landfill leachate, mix evenly, let stand for 1-2 hours, and simultaneously perform ultraviolet light irradiation treatment for 20-40 minutes to allow precipitation;

[0022] The amount of hydrogen peroxide added is 10-20 wt% of the landfill leachate, the wavelength of the ultraviolet light is 250-260 nm, and the power is 500-700 W.

[0023] Optionally, the porous spherical activated carbon adsorbent is prepared by the following method: rosin-based adsorption resin and triethylenetetramine are placed in xylene, mixed evenly, heated to a higher temperature, reacted, cooled after the reaction is completed, filtered, washed, and dried to obtain the porous spherical activated carbon adsorbent.

[0024] Furthermore, the porous spherical activated carbon adsorbent is prepared by the following method: rosin-based adsorption resin and triethylenetetramine are placed in xylene, mixed evenly, heated to 60-80℃, and reacted for 10-14 hours. After the reaction is completed, the temperature is cooled to 22±3℃, filtered, washed 3-5 times with sodium hydroxide solution and water, and dried to obtain the porous spherical activated carbon adsorbent.

[0025] The amount of xylene added per 1g of rosin-based adsorption resin is 3-5mL, and the concentration of sodium hydroxide solution is 0.1mol / L.

[0026] Rosin-based adsorption resins are prepared using the following method:

[0027] A1: Hydrogenated rosin pentaerythritol ester, maleate, divinylbenzene, azobisisobutyronitrile, and polyvinyl alcohol are mixed evenly to obtain mixture A;

[0028] A2: Sodium dodecyl sulfate, polyvinyl alcohol, and sodium chloride are placed in water to obtain mixture B;

[0029] A3: Heat mixture B to 50-60℃, add mixture A, mix well, continue heating to 70-90℃, and keep the temperature constant after white particles appear. Solidify for 1-3 hours, filter, wash with water 3-5 times, and dry to obtain the initial product.

[0030] A4: Place the initial product in a potassium hydroxide solution, ablate it in air for 20-40 minutes, then continue carbonization in nitrogen atmosphere for 2-4 hours, wash it with water 3-5 times, and dry it to obtain rosin-based adsorption resin.

[0031] In step A1, the weight ratio of hydrogenated rosin pentaerythritol ester to maleic acid ester is 1:(2-4), the weight ratio of hydrogenated rosin pentaerythritol ester to divinylbenzene is 1:(0.4-0.6), the weight ratio of hydrogenated rosin pentaerythritol ester to azobisisobutyronitrile is 1:(0.015-0.018), and the weight ratio of hydrogenated rosin pentaerythritol ester to polyvinyl alcohol is 1:(0.5-0.7); in step A2, the weight ratio of hydrogenated rosin pentaerythritol ester to sodium dodecyl sulfate is... The ratio is 1:(0.005-0.007), the weight ratio of hydrogenated rosin pentaerythritol ester and polyvinyl alcohol is 1:(0.005-0.007), the weight ratio of hydrogenated rosin pentaerythritol ester and sodium chloride is 1:(1-1.4), and the weight ratio of sodium dodecyl sulfate, polyvinyl alcohol, sodium chloride and water is 1:(4-6); in step A4, the amount of potassium hydroxide solution added per 1g of initial product is 1-3mL, and the concentration of potassium hydroxide solution is 1mol / L.

[0032] Optionally, the weight ratio of the triethylenetetramine and the rosin-based adsorption resin is (1-2):1.

[0033] Optionally, the anode of the electrochemical treatment in step S4 is any one of PbO2 / Ti, TiO2 / Ti, or graphite, the cathode is any one of iron plate, copper plate, or zinc plate, and the filler is MnO2-Fe2O3 supported on modified kaolin.

[0034] Furthermore, in step S4, the anode of the electrochemical treatment is any one of PbO2 / Ti, TiO2 / Ti, or graphite, the cathode is any one of iron plate, copper plate, or zinc plate, and the filler is modified kaolin-supported MnO2-Fe2O3; the anode is more preferably TiO2 / Ti, and the cathode is more preferably iron plate.

[0035] Optionally, the amount of filler in each kilogram of landfill leachate is 15-45g.

[0036] Optionally, the current density is 70-80 mA / cm². 2 The voltage is 13-18V, the electrolysis time is 150-200min, and the electrode spacing is 10-18mm.

[0037] Optionally, the filler is prepared using the following method:

[0038] A1: Add ferric nitrate nonahydrate to water and mix well to obtain mixture A;

[0039] A2: Add mixture A to manganese nitrate solution and mix well to obtain mixture B;

[0040] A3: The modified kaolin is placed in the mixture B, heated, allowed to stand, filtered, washed, dried, calcined, and cooled to obtain the filler.

[0041] Furthermore, the filler is prepared using the following method:

[0042] A1: Add ferric nitrate nonahydrate to water and mix well to obtain mixture A;

[0043] A2: Add mixture A to manganese nitrate solution and mix well to obtain mixture B;

[0044] A3: Add the modified kaolin to the mixture B, heat to 100-120℃, let stand for 4-6 hours, filter, wash with water 3-5 times, dry, then heat to 300-400℃ for calcination for 1-3 hours, cool to 22±3℃ to obtain the filler.

[0045] The weight ratio of modified kaolin to ferric nitrate nonahydrate is 1:(0.1-0.3), the weight ratio of ferric nitrate nonahydrate to water in step A1 is 1:(1-3), the weight ratio of modified kaolin to manganese nitrate solution is 1:(0.06-0.1), and the mass fraction of manganese nitrate solution is 50%.

[0046] Optionally, the modified kaolin is prepared by the following method: crushing and sieving the kaolin, calcining it, then soaking it in an acid solution, letting it stand, filtering, washing, and drying it to obtain the modified kaolin.

[0047] Furthermore, the modified kaolin is prepared by the following method: kaolin is crushed, passed through a 100-mesh sieve, calcined at a temperature of 800-1200℃, then soaked in a 40% hydrochloric acid solution, left to stand for 12-18 hours, filtered, washed with water 3-5 times, and dried to obtain modified kaolin.

[0048] The amount of hydrochloric acid solution added to each 1g of kaolin is 3-5mL.

[0049] As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages:

[0050] 1. This application employs pretreatment of landfill leachate to remove large suspended particles. The pretreated leachate is then subjected to a double oxidation treatment, where hydrogen peroxide generates highly oxidizing hydroxyl radicals under ultraviolet light irradiation. These radicals can efficiently decompose cyanide in coking wastewater, converting it into low-toxicity or non-toxic substances. The leachate is then adsorbed by porous spherical activated carbon adsorbent and finally subjected to electrochemical treatment. This process can oxidize or reduce pollutants, significantly improving the treatment efficiency of landfill leachate.

[0051] Among them, the porous spherical activated carbon adsorbent is an amination-modified rosin-based adsorption resin. Rosin is a natural and renewable resource. Its chemical modification prepares a rosin-based adsorption resin with polymerization function. The adsorption mechanism of the rosin-based adsorption resin is hydrogen bonding and pore-filling effect. These forces together provide the adsorption driving force, enabling the rosin-based adsorption resin to effectively adsorb COD from landfill leachate. Cr The adsorption of organic pollutants such as ammonia nitrogen is further enhanced by amination of the rosin-based adsorption resin. Amine groups are introduced onto the surface of the resin, increasing its polarity and surface activity, thereby improving its adsorption capacity for organic pollutants. Specifically, amine groups can form hydrogen bonds, electrostatic interactions, or coordination bonds with pollutants, and can also alter the pore structure of the rosin-based adsorption resin, increasing its specific surface area and further improving its adsorption performance. This makes it more effective for adsorbing COD from landfill leachate. Cr Removal of ammonia nitrogen.

[0052] 2. This application employs a three-dimensional electrode for electrochemical oxidation of landfill leachate. The three-dimensional electrolysis method possesses high oxidation characteristics. By creating a voltage difference under an applied voltage, a redox reaction occurs on the surface of the particle electrode, generating a large number of hydroxyl radicals. These radicals have extremely strong oxidizing properties, capable of destroying toxic and harmful functional groups in the landfill leachate, causing organic matter to undergo ring-opening and chain-breaking, converting it into carbon dioxide and water, thus improving the control of COD. Cr The removal effect of ammonia nitrogen;

[0053] 3. This application uses modified kaolin-supported MnO2-Fe2O3 as the filler. The combination of MnO2 and Fe2O3 can produce a synergistic catalytic effect, significantly improving the catalytic oxidation performance. Modified kaolin itself has a certain adsorption capacity, which can adsorb organic pollutants in landfill leachate. In addition, the kaolin supported on MnO2-Fe2O3 can increase the specific surface area, provide more catalytic active sites, further improve the electrochemical activity of the three-dimensional electrode system, promote the redox reaction on the electrode surface, and thus improve the treatment effect of landfill leachate.

[0054] 4. This application modifies kaolin using calcination and acid washing. High-temperature calcination effectively removes organic impurities, volatile substances, and some water from the kaolin, thereby increasing its specific surface area and adsorption capacity. Acid washing removes impurities such as metal oxides and carbonates from the kaolin, further increasing its specific surface area. Therefore, modifying kaolin facilitates improved treatment of landfill leachate. Detailed Implementation

[0055] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in the present invention can be purchased on the market or prepared by existing methods.

[0056] Preparation Example

[0057] Preparation Example 1

[0058] A rosin-based adsorbent resin is prepared by the following method:

[0059] A1: Mix 2 kg of hydrogenated rosin pentaerythritol ester, 6 kg of maleic acid ester, 1 kg of divinylbenzene, 0.033 kg of azobisisobutyronitrile, and 1.2 kg of polyvinyl alcohol evenly to obtain mixture A;

[0060] A2: Add 0.012 kg sodium dodecyl sulfate, 0.012 kg polyvinyl alcohol, and 2.4 kg sodium chloride to 12.12 kg of water to obtain mixture B;

[0061] A3: Heat mixture B to 55°C, add mixture A, mix well, continue heating to 80°C, and keep the temperature constant after white particles appear. Solidify for 2 hours, filter, wash with water 5 times, and dry to obtain the initial product.

[0062] A4: The initial product is placed in a potassium hydroxide solution with a concentration of 1 mol / L, and then etched in air for 30 min, followed by carbonization in nitrogen atmosphere for 3 h. After washing with water 4 times and drying, rosin-based adsorption resin is obtained; wherein, the amount of potassium hydroxide solution added to each 1 g of initial product is 2 mL.

[0063] Preparation Example 2

[0064] A porous spherical activated carbon adsorbent is prepared by the following method:

[0065] 1 kg of rosin-based adsorbent resin prepared in Preparation Example 1 and 1 kg of triethylenetetramine were placed in xylene, mixed evenly, heated to 70°C, and reacted for 12 h. After the reaction was completed, the mixture was cooled to 25°C, filtered, and washed 5 times successively with a 0.1 mol / L sodium hydroxide solution and water. After drying, porous spherical activated carbon adsorbent was obtained.

[0066] Preparation Example 3

[0067] A porous spherical activated carbon adsorbent differs from that in Preparation Example 2 in that the amount of triethylenetetramine added is different; in Preparation Example 3, the amount of triethylenetetramine added is 1.5 kg.

[0068] Preparation Example 4

[0069] A porous spherical activated carbon adsorbent differs from Preparation Example 2 in that the amount of triethylenetetramine added is different; in Preparation Example 4, the amount of triethylenetetramine added is 2 kg.

[0070] Preparation Example 5

[0071] A porous spherical activated carbon adsorbent differs from that in Preparation Example 2 in that the amount of triethylenetetramine added is different; in Preparation Example 5, the amount of triethylenetetramine added is 0.1 kg.

[0072] Preparation Example 6

[0073] A porous spherical activated carbon adsorbent differs from Preparation Example 2 in that the amount of triethylenetetramine added is different; in Preparation Example 6, the amount of triethylenetetramine added is 5 kg.

[0074] Preparation Example 7

[0075] A modified kaolin is prepared by the following method:

[0076] Kaolin was crushed, passed through a 100-mesh sieve, calcined at 1000℃, then soaked in a 40% hydrochloric acid solution, left to stand for 15 hours, filtered, washed five times with water, and dried to obtain modified kaolin; wherein, the amount of hydrochloric acid solution added to each 1g of kaolin was 4mL.

[0077] Preparation Example 8

[0078] A filler prepared by the following method:

[0079] A1: Add 2 kg of ferric nitrate nonahydrate to 4 kg of water and mix well to obtain mixture A;

[0080] A2: Add mixture A to 0.8 kg of 50% manganese nitrate solution and mix well to obtain mixture B;

[0081] A3: Add 10 kg of the modified kaolin prepared in Preparation Example 7 to the mixture B, heat to 110°C, let stand for 5 h, filter, wash with water 5 times, dry, then heat to 350°C for calcination for 2 h, cool to 25°C to obtain the filler.

[0082] Example

[0083] Example 1

[0084] A combined oxidation-electrochemical oxidation process for treating landfill leachate includes the following steps:

[0085] S1: Allow 10 kg of landfill leachate to settle naturally for 5 hours, filter it through a screen, collect the filtrate, and then treat the filtrate with oil separation for 80 minutes to obtain pretreated landfill leachate;

[0086] S2: Add 1.5 kg of hydrogen peroxide to the pretreated landfill leachate, mix well, let stand for 1.5 h, and simultaneously irradiate with ultraviolet light at a wavelength of 255 nm and a power of 600 W for 30 min to allow precipitation. After filtration, the treated liquid A is obtained.

[0087] S3: Add 0.6 kg of porous spherical activated carbon adsorbent prepared in Preparation Example 2 to treatment solution A, mix well, let stand for 1.5 h, then strip for 7 min, filter to obtain treatment solution B;

[0088] S4: Using a PbO2 / Ti anode and an iron plate cathode, with 15g of filler material, a three-dimensional electrode prepared in Preparation Example 8 was used, at a current density of 75mA / cm². 2 Under conditions of 15V voltage and 14mm electrode spacing, the treatment solution B was electrochemically oxidized for 180min and then discharged after filtration.

[0089] Examples 2-5

[0090] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 1 in that the source of the porous spherical activated carbon adsorbent in step S3 is different. The porous spherical activated carbon adsorbents in Examples 2-5 were prepared using Preparation Examples 3-6, respectively.

[0091] Example 6

[0092] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 2 in that the amount of filler in step S4 is different; in Example 6, the amount of filler is 30g.

[0093] Example 7

[0094] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 2 in that the amount of filler in step S4 is different; in Example 7, the amount of filler is 45g.

[0095] Comparative Example

[0096] Comparative Example 1

[0097] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 1 in that the porous spherical activated carbon adsorbent in step S3 is replaced in equal amounts with rosin-based adsorption resin.

[0098] Comparative Example 2

[0099] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 1 in that the porous spherical activated carbon adsorbent in step S3 is replaced with an equal amount of polyacrylamide.

[0100] Comparative Example 3

[0101] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 1 in that, in step S4, MnO2 in the packing is replaced with an equal amount of Fe2O3.

[0102] Comparative Example 4

[0103] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 1 in that, in step S4, Fe2O3 in the packing is replaced by an equal amount of MnO2.

[0104] Comparative Example 5

[0105] A combined oxidation-electrochemical oxidation process for treating landfill leachate differs from Example 1 in that no filler is added in step S4.

[0106] Performance testing

[0107] The following performance tests were conducted on the landfill leachate treated in Examples 1-7 and Comparative Examples 1-5:

[0108] COD Cr According to CJT428-2013 "Test Method for Leachate from Municipal Solid Waste", the COD in the treated leachate was measured. Cr The measurements were performed, and the results are shown in Table 1.

[0109] Ammonia nitrogen: The ammonia nitrogen in the leachate of treated municipal solid waste was determined according to CJT428-2013 "Test Method for Leachate from Municipal Solid Waste". The test results are shown in Table 1.

[0110] Among them, COD in the landfill leachate before treatment Cr The concentration was 41,600 mg / L, and the ammonia nitrogen content was 1,200 mg / L.

[0111] Table 1 Test Results

[0112]

[0113] As can be seen from Table 1, the combined oxidation-electrochemical oxidation process for treating landfill leachate in this application effectively reduces the COD in the leachate through the synergistic effect of each step. cr The content of ammonia nitrogen, including COD Cr The removal rate of nitrogen is 89.4-99.8%, and the removal rate of ammonia nitrogen is 86.7-99.3%.

[0114] As can be seen from Example 1 and Comparative Examples 1-2, the COD in Example 1 Cr The removal rate of COD was 92.9%, and the removal rate of ammonia nitrogen was 91.3%, which was better than that of comparative examples 1-2. This indicates that the porous spherical activated carbon adsorbent is more suitable as an amination-modified rosin-based adsorption resin, and the rosin-based adsorption resin can effectively adsorb COD in wastewater. CrOrganic pollutants such as ammonia nitrogen are adsorbed by amination. Further modification with amination introduces amine groups onto the resin surface, increasing polarity and surface activity, thus enhancing the adsorption capacity for organic pollutants and making it more effective for adsorbing COD from coking wastewater. Cr Removal of ammonia nitrogen.

[0115] As can be seen from Example 1 and Comparative Examples 3-5, the COD in Example 1 Cr The removal rate of nitrogen was 92.9%, and the removal rate of ammonia nitrogen was 91.3%, which was better than that of comparative examples 3-5. This indicates that modified kaolin-supported MnO2-Fe2O3 is more suitable as the packing material. Through the synergistic effect among the three, the catalytic oxidation activity was further improved, which is more conducive to improving the treatment effect of landfill leachate.

[0116] As can be seen from Examples 1-5, the COD in Example 2 Cr The removal rate of COD was 95.3%, and the removal rate of ammonia nitrogen was 94.8%, which is better than other examples. This indicates that the porous spherical activated carbon adsorbent prepared by Preparation Example 3 is more suitable, and the amount of triethylenetetramine added in Preparation Example 3 is more appropriate. When the amount of triethylenetetramine added is too small, the modification effect on the rosin-based adsorption resin is not good, which leads to poor adsorption effect of the porous spherical activated carbon adsorbent. When the amount of triethylenetetramine added is too large, the excessive amine groups will cause the structure of the rosin-based adsorption resin to be unstable, resulting in the active sites on the surface of the rosin-based adsorption resin being too dense, which will reduce the adsorption of organic pollutants and is not conducive to COD removal in coking wastewater. Cr Removal of ammonia nitrogen.

[0117] As can be seen from Examples 2 and 6-7, the COD in Example 6 Cr The removal rate of leachate was 99.8%, and the removal rate of ammonia nitrogen was 99.3%, which was better than other embodiments. This indicates that the filling amount of the filler in Embodiment 6 was more suitable. A smaller filling amount could not play a better role, resulting in a lower electrolysis effect on the leachate. A larger filling amount could easily lead to short-circuit current and coverage problems, which would also affect the treatment of leachate. Therefore, only when the filling amount of the filler is within the above range can it achieve a better treatment effect on the leachate.

[0118] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A combined oxidation-electrochemical oxidation process for treating landfill leachate, characterized in that: Includes the following steps: S1: Pre-treat the landfill leachate to obtain pre-treated landfill leachate; S2: The pretreated landfill leachate is subjected to double oxidation treatment, and then filtered to obtain treated liquid A; S3: Add porous spherical activated carbon adsorbent to treatment solution A, mix evenly, let stand, then strip and filter to obtain treatment solution B; S4: Electrochemically oxidize the treatment solution B, let it stand, filter it, and then discharge it. Among them, the porous spherical activated carbon adsorbent is an amination-modified rosin-based adsorption resin; The porous spherical activated carbon adsorbent is prepared by the following method: rosin-based adsorption resin and triethylenetetramine are placed in xylene, mixed evenly, heated to a higher temperature, reacted, cooled after the reaction is completed, filtered, washed, and dried to obtain the porous spherical activated carbon adsorbent. The weight ratio of the triethylenetetramine and the rosin-based adsorption resin is (1-2):1; In step S4, the anode for electrochemical oxidation is any one of PbO2 / Ti, TiO2 / Ti, or graphite, the cathode is any one of iron plate, copper plate, or zinc plate, and the filler is modified kaolin-supported MnO2-Fe2O3. The filler is prepared using the following method: A1: Add ferric nitrate nonahydrate to water and mix well to obtain mixture A; A2: Add mixture A to manganese nitrate solution and mix well to obtain mixture B; A3: The modified kaolin is placed in the mixture B, heated, allowed to stand, filtered, washed, dried, calcined, and cooled to obtain the filler. The specific steps of hydrogen peroxide treatment in step S2 are as follows: add hydrogen peroxide to the pretreated landfill leachate, mix well, let stand, and simultaneously perform ultraviolet irradiation treatment to induce precipitation; The modified kaolin is prepared by the following method: kaolin is crushed, sieved, calcined, then soaked in an acid solution, allowed to stand, filtered, washed, and dried to obtain modified kaolin.

2. The combined oxidation-electrochemical oxidation process for treating landfill leachate according to claim 1, characterized in that: The specific steps of the pretreatment in step S1 are as follows: allow the landfill leachate to settle naturally, filter it through a screen, collect the filtrate, and perform oil separation treatment on the filtrate to obtain the pretreated landfill leachate.

3. The combined oxidation-electrochemical oxidation process for treating landfill leachate according to claim 1, characterized in that: The amount of filler in each kilogram of landfill leachate is 15-45g.

4. The combined oxidation-electrochemical oxidation process for treating landfill leachate according to claim 1, characterized in that: The current density of the electrochemical oxidation is 70-80 mA / cm². 2 The voltage is 13-18V, the electrolysis time is 150-200min, and the electrode spacing is 10-18mm.

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