A landfill leachate oxidation treatment device

Abstract

The invention discloses an oxidation treatment device for landfill leachate, comprising an ozone generator, two micro-nano bubble generators, a stabilizing column, a first catalytic reaction column, a second catalytic reaction column, and an MNR biochemical reaction system. The process of the invention is fully enclosed and pressurized, has no risk of ozone leakage, is safe and environmentally friendly, and adopts micro-nano ozone bubble generation technology when treating the leachate, with an ozone utilization rate of more than 96%, and substantially no ozone smell in tail gas; at the same time, an ozone catalyst is adopted in the first oxidation reaction column and the second oxidation reaction column, and the microenvironment in which the ozone catalyst is located can have a strong limiting effect on the physical and chemical state of the catalytic system, further improving the catalytic efficiency, thereby specifically removing the difficult-to-degrade characteristic organic pollutants in the landfill leachate, overcoming the problem of easy passivation and deactivation of conventional ozone catalysts, having a long service life, and enhancing the efficiency of catalytic ozone oxidation.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment, and in particular to an oxidation treatment device for landfill leachate. Background Art

[0002] The landfill leachate is currently treated using the "homogenization tank + membrane bioreactor (MBR) + nanofiltration (NF) + reverse osmosis (RO)" process. After the leachate wastewater is treated by the MBR, nanofiltration, and reverse osmosis systems, the clean water meets the discharge standards. After the humic acid is extracted from the concentrated liquid produced by the nanofiltration, it is further disposed by the evaporation system. The concentrated liquid produced by the reverse osmosis directly enters the combustion evaporation system for treatment. Due to the high cost of concentrated liquid treatment and the difficulty of operation, the efficiency is low. At the same time, the more easily degradable organic matter in the concentrated liquid wastewater after the treatment of the landfill leachate has been completely utilized by microorganisms. The remaining organic matter is difficult to degrade macromolecular organic matter, such as phenolic compounds, nitrogen-containing compounds, esters and ketones, olefins, alkanes, alcohols, polycyclic aromatic hydrocarbons, amines and phthalates. They cannot participate in biological reactions as nutrient sources and are difficult to be directly treated by conventional biochemical processes. Advanced oxidation technology can decompose difficult-to-degrade organic matter into small molecular organic matter, which is increasingly becoming an important method for the treatment of difficult-to-degrade organic matter as a carbon source for biological use.

[0003] At present, the advanced oxidation technologies for landfill leachate concentrate mainly include ozone oxidation, electrocatalytic oxidation, photocatalytic oxidation, Fenton oxidation, persulfate oxidation, ultrasonic oxidation and other methods. Among them, the effective utilization rate of ozone in the traditional ozone catalytic oxidation process is not high, and the reaction efficiency is relatively low. Some free radicals are quenched before they react, resulting in a large amount of ozone addition, large investment and high operating costs. The Fenton oxidation method has the advantages of simple equipment, easy operation, fast reaction speed and stable effluent properties. It has been gradually promoted in actual wastewater treatment projects, but the Fenton reaction also has the following shortcomings: high treatment cost, easy color reversal, difficult to control reaction conditions, strong reaction corrosiveness and difficult transportation and storage. Photocatalytic oxidation technology mainly uses TiO2 nanomaterials, which are mainly used in two forms. One is to use nano-titanium and titanium dioxide. The first method is to directly mix rice particles with the sewage to be treated, and stir to evenly disperse the catalyst and fully mix it with the photolyzed material to form a suspended system. The second method is to load the nanoparticles on a certain carrier (such as a ceramic membrane) to form a loaded system. The suspended system is relatively simple and convenient, and due to its large specific surface area, it has a better adsorption effect on organic matter and a better absorption of photons, and is in more complete contact with the photolyzed material and receives sufficient light, thus having a better photolysis effect. However, both forms of use have certain disadvantages. The use of nanomaterials in the suspended system has the disadvantages that the catalyst powder is difficult to be effectively separated and recovered, and it is easy to agglomerate in the aqueous solution, resulting in the loss of active ingredients. The advantage of the loaded system is that the catalyst is fixed, which is more conducive to the recycling of the catalyst, but at the same time it affects the degradation rate and effect. The research on the treatment of landfill leachate by immobilized photocatalytic membranes is still immature. Summary of the invention

[0004] In view of the defects of the prior art, the purpose of the present invention is to provide a landfill leachate oxidation treatment device to solve the problems raised in the above background technology.

[0005] The present invention solves the technical problem by adopting the following technical solution:

[0006] The present invention comprises an ozone generator, two micro-nano bubble generators, a stabilizing column, a No. 1 catalytic reaction column, a No. 2 catalytic reaction column, and an MNR biochemical reaction system;

[0007] The treatment process of the landfill leachate oxidation treatment device comprises the following steps:

[0008] Step 1: adding a coagulant and a coagulant aid to the landfill leachate concentrate to perform coagulation and precipitation to obtain a primary clear liquid;

[0009] Step 2: Turn on the ozone generator. After the ozone generator can stably produce ozone, open the gas control valve between the ozone generator and the micro-nano bubble generator to allow the ozone to stably enter the micro-nano bubble generator.

[0010] Step 3: Start the micro-nano bubble generator, inject the primary clear liquid in step 1 into the micro-nano bubble generator through the liquid inlet pipe, and the leachate containing ozone micro-nano bubbles enters the stabilization column through the liquid outlet pipe of the micro-nano bubble generator, and fully reacts to obtain the secondary clear liquid;

[0011] Step 4: Under the action of pressure, the secondary clear liquid enters the bottom of the No. 1 catalytic reaction column through the pipeline at the top of the stabilizing column, and at the same time, another micro-nano bubble generator generates bubbles inside the No. 1 catalytic reaction column, so that the secondary clear liquid fully reacts with the ozone catalyst inside the No. 1 catalytic reaction column to obtain a tertiary clear liquid;

[0012] Step 5: Under the action of pressure, the third-level clear liquid enters the bottom of the second catalytic reaction column through the pipeline at the top of the first catalytic reaction column, and reacts with the ozone catalyst in the second catalytic reaction column to obtain a fourth-level clear liquid;

[0013] Step 6: Under the action of pressure, the fourth-level clear liquid enters the top of the MNR biochemical reaction system through the pipeline at the top of the No. 2 catalytic reaction column. At the same time, the ozone generator is connected with the pipeline between the No. 2 catalytic reaction column and the MNR biochemical reaction system through the pipeline, so that the fourth-level clear liquid and ozone react again and enter the MNR biochemical reaction system at the same time, and finally discharged from the drain outlet of the MNR biochemical reaction system.

[0014] Preferably, the coagulant in step one includes any one of polyferric sulfate and polyaluminium chloride, and the coagulant aid is polyacrylamide.

[0015] Preferably, the amount of the coagulant added is 0.1-2 kg / m3, and the amount of the coagulant aid added is 0.01-0.5 kg / m3.

[0016] Preferably, the flow rate of ozone in step 2 is 1.5-2.0 L / min, and the flow rate of filtrate entering the micro-nano bubble generator in step 3 is 20-30 L / min.

[0017] Preferably, the ozone catalyst is composed of a catalytic carrier made of a composite porous silicon-aluminum material and a catalytic component loaded on the catalytic carrier, and the catalytic component is composed of a transition metal and a rare earth metal.

[0018] Preferably, the transition metal is one or more of Fe, Cu, Mn, Ti, and Zn, and the transition metal accounts for 0.1%-20.0% of the total mass of the catalyst in terms of oxide; the rare earth metal is one or more of lanthanum, cerium, praseodymium, and neodymium.

[0019] Preferably, the composite porous silicon-aluminum material is in the form of nanosheets, has a silicon oxide content of 1-20wt%, and a specific surface area of ​​800-1000m2 / g.

[0020] Preferably, the method for preparing the catalyst carrier comprises the following steps:

[0021] S1. preparing an impregnation solution containing a catalytic component;

[0022] S2, contacting gibbsite with sodium hydroxide at 110-150° C. for 12-24 hours to obtain a sodium aluminate solution;

[0023] S3, adding the sodium aluminate solution dropwise into the aluminum sulfate solution under stirring;

[0024] S4, adding sodium aluminate solution, aluminum sulfate solution and water glass dropwise to the suspension obtained in step S3 under stirring;

[0025] S5, crystallizing the product obtained in step S4 at a temperature of 50-140° C. for 6-24 hours;

[0026] S6. Filter the crystallized product obtained in step S5, and wash the filtered solid with deionized water and dry it at a drying temperature of 60-170° C. to obtain a catalytic carrier.

[0027] S7. Immerse the catalyst carrier prepared in S6 in the impregnation solution prepared in S1 for 30-40 minutes.

[0028] S8. Wash, dry, calcine at high temperature, and cool under inert gas the porous silicon-alumina carrier loaded with multiple metals obtained in S7 to prepare an ozone catalyst.

[0029] Preferably, the mass concentration of the catalytic component contained in the impregnation solution in S1 is 1wt%-5wt% in terms of metal; the molar ratio of Na / Al of sodium hydroxide to gibbsite in S2 is (2-5):1, and the concentration of the aluminum sulfate solution in S3 is 0.1-1 mol / kg.

[0030] Preferably, the drying temperature in S8 is 50-100° C., the high temperature calcination operation is performed at 500-600° C. for 3-5 hours; and the inert gas is nitrogen or argon.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The process flow of the present invention is fully enclosed and pressurized, without the risk of ozone leakage, and is safe and environmentally friendly. Micro-nano ozone bubble generation technology is used when treating the leachate, and the ozone utilization rate reaches more than 96%, and the tail gas has basically no ozone smell. At the same time, ozone catalysts are used in the first oxidation reaction column and the second oxidation reaction column, and the catalytic carrier is made of composite porous silicon-aluminum material, and transition metals and rare earth metals are used as catalytic components. Multi-metal oxide composite ozone catalysis not only has strong catalytic activity, but also can construct catalytic active centers in nanopores. The microenvironment in which it is located can have a strong limiting effect on the physical and chemical state of the catalytic system, and the catalytic efficiency is further improved, so as to specifically remove the difficult-to-degrade characteristic organic pollutants in the landfill leachate, overcome the problem of easy passivation and deactivation of conventional ozone catalysts, have a long service life, and enhance the efficiency of catalytic ozone oxidation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the ozone nano-catalytic oxidation process of the present invention.

[0034] Figure 2 It is a schematic diagram of the ozone catalyst of the present invention and its surface microstructure. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The present invention of this embodiment provides a landfill leachate oxidation treatment device, including an ozone generator, two micro-nano bubble generators, a stabilizing column, a No. 1 catalytic reaction column, a No. 2 catalytic reaction column, and an MNR biochemical reaction system;

[0037] The treatment process of the landfill leachate oxidation treatment device includes the following steps:

[0038] Step 1: adding a coagulant and a coagulant aid to the landfill leachate concentrate to perform coagulation and precipitation to obtain a primary clear liquid;

[0039] Step 2: Turn on the ozone generator. After the ozone generator can stably produce ozone, open the gas control valve between the ozone generator and the micro-nano bubble generator to allow the ozone to stably enter the micro-nano bubble generator.

[0040] Step 3: Start the micro-nano bubble generator, inject the primary clear liquid in step 1 into the micro-nano bubble generator through the liquid inlet pipe, and the leachate containing ozone micro-nano bubbles enters the stabilization column through the liquid outlet pipe of the micro-nano bubble generator, and fully reacts to obtain the secondary clear liquid;

[0041] Step 4: Under the action of pressure, the secondary clear liquid enters the bottom of the No. 1 catalytic reaction column through the pipeline at the top of the stabilizing column, and at the same time, another micro-nano bubble generator generates bubbles inside the No. 1 catalytic reaction column, so that the secondary clear liquid fully reacts with the ozone catalyst inside the No. 1 catalytic reaction column to obtain a tertiary clear liquid;

[0042] Step 5: Under the action of pressure, the third-level clear liquid enters the bottom of the second catalytic reaction column through the pipeline at the top of the first catalytic reaction column, and reacts with the ozone catalyst in the second catalytic reaction column to obtain a fourth-level clear liquid;

[0043] Step 6: Under the action of pressure, the fourth-level clear liquid enters the top of the MNR biochemical reaction system through the pipeline at the top of the No. 2 catalytic reaction column. At the same time, the ozone generator is connected with the pipeline between the No. 2 catalytic reaction column and the MNR biochemical reaction system through the pipeline, so that the fourth-level clear liquid and ozone react again and enter the MNR biochemical reaction system at the same time, and finally discharged from the drain outlet of the MNR biochemical reaction system.

[0044] The coagulant in step 1 of this embodiment includes any one of polyferric sulfate and polyaluminium chloride, and the coagulant aid is polyacrylamide.

[0045] The amount of coagulant added in this embodiment is 0.1-2 kg / m 3 The amount of coagulant added is 0.01-0.5kg / m 3 .

[0046] In step 2 of this embodiment, the flow rate of ozone is 1.5-2.0 L / min, and the flow rate of the influent filtrate of the micro-nano bubble generator in step 3 is 20-30 L / min.

[0047] The ozone catalyst of this embodiment is composed of a catalytic carrier made of a composite porous silicon-aluminum material and a catalytic component loaded on the catalytic carrier, and the catalytic component is composed of a transition metal and a rare earth metal.

[0048] The transition metal of this embodiment is one or more of Fe, Cu, Mn, Ti, and Zn, and the transition metal accounts for 0.1%-20.0% of the total mass of the catalyst in terms of oxide; the rare earth metal is one or more of lanthanum, cerium, praseodymium, and neodymium.

[0049] The composite porous silicon-aluminum material of this embodiment is in the form of nanosheets, with a silicon oxide content of 1-20wt% and a specific surface area of ​​800-1000m2 / g.

[0050] The preparation method of the catalyst carrier of this embodiment comprises the following steps:

[0051] S1. preparing an impregnation solution containing a catalytic component;

[0052] S2, contacting gibbsite with sodium hydroxide at 110-150° C. for 12-24 hours to obtain a sodium aluminate solution;

[0053] S3, adding the sodium aluminate solution dropwise into the aluminum sulfate solution under stirring;

[0054] S4, adding sodium aluminate solution, aluminum sulfate solution and water glass dropwise to the suspension obtained in step S3 under stirring;

[0055] S5, crystallizing the product obtained in step S4 at a temperature of 50-140° C. for 6-24 hours;

[0056] S6. Filter the crystallized product obtained in step S5, and wash the filtered solid with deionized water and dry it at a drying temperature of 60-170° C. to obtain a catalytic carrier.

[0057] S7. Immerse the catalyst carrier prepared in S6 in the impregnation solution prepared in S1 for 30-40 minutes.

[0058] S8. Wash, dry, calcine at high temperature, and cool under inert gas the porous silicon-alumina carrier loaded with multiple metals obtained in S7 to prepare an ozone catalyst.

[0059] The mass concentration of the catalytic component contained in the impregnation solution in S1 of this embodiment is 1wt%-5wt% in terms of metal; the molar ratio of Na / Al of sodium hydroxide to gibbsite in S2 is (2-5):1, and the concentration of the aluminum sulfate solution in S3 is 0.1-1mol / kg.

[0060] In S8 of this embodiment, the drying temperature is 50-100° C., and the high-temperature calcination operation is performed at 500-600° C. for 3-5 hours; the inert gas is nitrogen or argon.

[0061] Example 1.

[0062] The present invention of this embodiment provides a landfill leachate oxidation treatment device, including an ozone generator, two micro-nano bubble generators, a stabilizing column, a No. 1 catalytic reaction column, a No. 2 catalytic reaction column, and an MNR biochemical reaction system;

[0063] The treatment process of the landfill leachate oxidation treatment device includes the following steps:

[0064] Step 1: adding a coagulant and a coagulant aid to the landfill leachate concentrate to perform coagulation and precipitation to obtain a primary clear liquid;

[0065] Step 2: Turn on the ozone generator. After the ozone generator can stably produce ozone, open the gas control valve between the ozone generator and the micro-nano bubble generator to allow the ozone to stably enter the micro-nano bubble generator.

[0066] Step 3: Start the micro-nano bubble generator, inject the primary clear liquid in step 1 into the micro-nano bubble generator through the liquid inlet pipe, and the leachate containing ozone micro-nano bubbles enters the stabilization column through the liquid outlet pipe of the micro-nano bubble generator, and fully reacts to obtain the secondary clear liquid;

[0067] Step 4: Under the action of pressure, the secondary clear liquid enters the bottom of the No. 1 catalytic reaction column through the pipeline at the top of the stabilizing column, and at the same time, another micro-nano bubble generator generates bubbles inside the No. 1 catalytic reaction column, so that the secondary clear liquid fully reacts with the ozone catalyst inside the No. 1 catalytic reaction column to obtain a tertiary clear liquid;

[0068] Step 5: Under the action of pressure, the third-level clear liquid enters the bottom of the second catalytic reaction column through the pipeline at the top of the first catalytic reaction column, and reacts with the ozone catalyst in the second catalytic reaction column to obtain a fourth-level clear liquid;

[0069] Step 6: Under the action of pressure, the fourth-level clear liquid enters the top of the MNR biochemical reaction system through the pipeline at the top of the No. 2 catalytic reaction column. At the same time, the ozone generator is connected with the pipeline between the No. 2 catalytic reaction column and the MNR biochemical reaction system through the pipeline, so that the fourth-level clear liquid and ozone react again and enter the MNR biochemical reaction system at the same time, and finally discharged from the drain outlet of the MNR biochemical reaction system.

[0070] The coagulant in step 1 of this embodiment includes any one of polyferric sulfate and polyaluminium chloride, and the coagulant aid is polyacrylamide.

[0071] The amount of coagulant added in this embodiment is 0.1 kg / m 3 The amount of coagulant added is 0.01kg / m 3 .

[0072] In step 2 of this embodiment, the flow rate of ozone is 1.5 L / min, and the flow rate of filtrate entering the micro-nano bubble generator in step 3 is 20 L / min.

[0073] The ozone catalyst of this embodiment is composed of a catalytic carrier made of a composite porous silicon-aluminum material and a catalytic component loaded on the catalytic carrier, and the catalytic component is composed of a transition metal and a rare earth metal.

[0074] The transition metals in this embodiment are Fe and Cu, and the transition metals account for 0.1% of the total mass of the catalyst in terms of oxides; the rare earth metal is lanthanum.

[0075] The composite porous silicon-aluminum material of this embodiment is in the form of nanosheets, with a silicon oxide content of 1wt% and a specific surface area of ​​800m 2 / g.

[0076] The preparation method of the catalyst carrier of this embodiment comprises the following steps:

[0077] S1. preparing an impregnation solution containing a catalytic component;

[0078] S2, contacting gibbsite with sodium hydroxide at 110° C. for 12 hours to obtain a sodium aluminate solution;

[0079] S3, adding the sodium aluminate solution dropwise into the aluminum sulfate solution under stirring;

[0080] S4, adding sodium aluminate solution, aluminum sulfate solution and water glass dropwise to the suspension obtained in step S3 under stirring;

[0081] S5, crystallizing the product obtained in step S4 at 50° C. for 6 h;

[0082] S6. Filter the crystallized product obtained in step S5, and wash the filtered solid with deionized water and dry it at a drying temperature of 60° C. to obtain a catalytic carrier.

[0083] S7. Immerse the catalyst carrier prepared in S6 in the impregnation solution prepared in S1 for 30 minutes.

[0084] S8. Wash, dry, calcine at high temperature, and cool under inert gas the porous silicon-alumina carrier loaded with multiple metals obtained in S7 to prepare an ozone catalyst.

[0085] The mass concentration of the catalytic component contained in the impregnation solution in S1 of this embodiment is 1wt% in terms of metal; the molar ratio of Na / Al of sodium hydroxide to gibbsite in S2 is 2:1, and the concentration of the aluminum sulfate solution in S3 is 0.1 / kg.

[0086] In S8 of this embodiment, the drying temperature is 50° C., and the high-temperature calcination operation is performed at 500° C. for 3 h; the inert gas is nitrogen or argon.

[0087] Example 2.

[0088] The present invention of this embodiment provides a landfill leachate oxidation treatment device, including an ozone generator, two micro-nano bubble generators, a stabilizing column, a No. 1 catalytic reaction column, a No. 2 catalytic reaction column, and an MNR biochemical reaction system;

[0089] The treatment process of the landfill leachate oxidation treatment device includes the following steps:

[0090] Step 1: adding a coagulant and a coagulant aid to the landfill leachate concentrate to perform coagulation and precipitation to obtain a primary clear liquid;

[0091] Step 2: Turn on the ozone generator. After the ozone generator can stably produce ozone, open the gas control valve between the ozone generator and the micro-nano bubble generator to allow the ozone to stably enter the micro-nano bubble generator.

[0092] Step 3: Start the micro-nano bubble generator, inject the primary clear liquid in step 1 into the micro-nano bubble generator through the liquid inlet pipe, and the leachate containing ozone micro-nano bubbles enters the stabilization column through the liquid outlet pipe of the micro-nano bubble generator, and fully reacts to obtain the secondary clear liquid;

[0093] Step 4: Under the action of pressure, the secondary clear liquid enters the bottom of the No. 1 catalytic reaction column through the pipeline at the top of the stabilizing column, and at the same time, another micro-nano bubble generator generates bubbles inside the No. 1 catalytic reaction column, so that the secondary clear liquid fully reacts with the ozone catalyst inside the No. 1 catalytic reaction column to obtain a tertiary clear liquid;

[0094] Step 5: Under the action of pressure, the third-level clear liquid enters the bottom of the second catalytic reaction column through the pipeline at the top of the first catalytic reaction column, and reacts with the ozone catalyst in the second catalytic reaction column to obtain a fourth-level clear liquid;

[0095] Step 6: Under the action of pressure, the fourth-level clear liquid enters the top of the MNR biochemical reaction system through the pipeline at the top of the No. 2 catalytic reaction column. At the same time, the ozone generator is connected with the pipeline between the No. 2 catalytic reaction column and the MNR biochemical reaction system through the pipeline, so that the fourth-level clear liquid and ozone react again and enter the MNR biochemical reaction system at the same time, and finally discharged from the drain outlet of the MNR biochemical reaction system.

[0096] The coagulant in step 1 of this embodiment includes any one of polyferric sulfate and polyaluminium chloride, and the coagulant aid is polyacrylamide.

[0097] The amount of coagulant added in this embodiment is 2kg / m 3 The amount of coagulant added is 0.5kg / m 3 .

[0098] In step 2 of this embodiment, the flow rate of ozone is 2.0 L / min, and the flow rate of filtrate entering the micro-nano bubble generator in step 3 is 30 L / min.

[0099] The ozone catalyst of this embodiment is composed of a catalytic carrier made of a composite porous silicon-aluminum material and a catalytic component loaded on the catalytic carrier, and the catalytic component is composed of a transition metal and a rare earth metal.

[0100] The transition metals in this embodiment are Ti and Zn, and the transition metals account for 20.0% of the total mass of the catalyst in terms of oxides; the rare earth metals are praseodymium and neodymium.

[0101] The composite porous silicon-aluminum material of this embodiment is in the form of nanosheets, with a silicon oxide content of 20wt% and a specific surface area of ​​1000m 2 / g.

[0102] The preparation method of the catalyst carrier of this embodiment comprises the following steps:

[0103] S1. preparing an impregnation solution containing a catalytic component;

[0104] S2, contacting gibbsite with sodium hydroxide at 150° C. for 24 hours to obtain a sodium aluminate solution;

[0105] S3, adding the sodium aluminate solution dropwise into the aluminum sulfate solution under stirring;

[0106] S4, adding sodium aluminate solution, aluminum sulfate solution and water glass dropwise to the suspension obtained in step S3 under stirring;

[0107] S5, crystallizing the product obtained in step S4 at 140° C. for 24 hours;

[0108] S6. Filter the crystallized product obtained in step S5, and wash the filtered solid with deionized water and dry it at a drying temperature of 170° C. to obtain a catalytic carrier.

[0109] S7. Immerse the catalyst carrier prepared in S6 in the impregnation solution prepared in S1 for 40 minutes.

[0110] S8. Wash, dry, calcine at high temperature, and cool under inert gas the porous silicon-alumina carrier loaded with multiple metals obtained in S7 to prepare an ozone catalyst.

[0111] The mass concentration of the catalytic component contained in the impregnation solution in S1 of this embodiment is 5wt% in terms of metal; the molar ratio of Na / Al of sodium hydroxide to gibbsite in S2 is 5:1, and the concentration of the aluminum sulfate solution in S3 is 1 mol / kg.

[0112] In S8 of this embodiment, the drying temperature is 100° C., and the high-temperature calcination operation is performed at 600° C. for 5 h; the inert gas is nitrogen or argon.

[0113] Example 3.

[0114] The present invention of this embodiment provides a landfill leachate oxidation treatment device, including an ozone generator, two micro-nano bubble generators, a stabilizing column, a No. 1 catalytic reaction column, a No. 2 catalytic reaction column, and an MNR biochemical reaction system;

[0115] The treatment process of the landfill leachate oxidation treatment device includes the following steps:

[0116] Step 1: adding a coagulant and a coagulant aid to the landfill leachate concentrate to perform coagulation and precipitation to obtain a primary clear liquid;

[0117] Step 2: Turn on the ozone generator. After the ozone generator can stably produce ozone, open the gas control valve between the ozone generator and the micro-nano bubble generator to allow the ozone to stably enter the micro-nano bubble generator.

[0118] Step 3: Start the micro-nano bubble generator, inject the primary clear liquid in step 1 into the micro-nano bubble generator through the liquid inlet pipe, and the leachate containing ozone micro-nano bubbles enters the stabilization column through the liquid outlet pipe of the micro-nano bubble generator, and fully reacts to obtain the secondary clear liquid;

[0119] Step 4: Under the action of pressure, the secondary clear liquid enters the bottom of the No. 1 catalytic reaction column through the pipeline at the top of the stabilizing column, and at the same time, another micro-nano bubble generator generates bubbles inside the No. 1 catalytic reaction column, so that the secondary clear liquid fully reacts with the ozone catalyst inside the No. 1 catalytic reaction column to obtain a tertiary clear liquid;

[0120] Step 5: Under the action of pressure, the third-level clear liquid enters the bottom of the second catalytic reaction column through the pipeline at the top of the first catalytic reaction column, and reacts with the ozone catalyst in the second catalytic reaction column to obtain a fourth-level clear liquid;

[0121] Step 6: Under the action of pressure, the fourth-level clear liquid enters the top of the MNR biochemical reaction system through the pipeline at the top of the No. 2 catalytic reaction column. At the same time, the ozone generator is connected with the pipeline between the No. 2 catalytic reaction column and the MNR biochemical reaction system through the pipeline, so that the fourth-level clear liquid and ozone react again and enter the MNR biochemical reaction system at the same time, and finally discharged from the drain outlet of the MNR biochemical reaction system.

[0122] The coagulant in step 1 of this embodiment includes any one of polyferric sulfate and polyaluminium chloride, and the coagulant aid is polyacrylamide.

[0123] The amount of coagulant added in this embodiment is 1 kg / m 3 The amount of coagulant added is 0.25kg / m 3 .

[0124] In step 2 of this embodiment, the flow rate of ozone is 1.8 L / min, and the flow rate of filtrate entering the micro-nano bubble generator in step 3 is 25 L / min.

[0125] The ozone catalyst of this embodiment is composed of a catalytic carrier made of a composite porous silicon-aluminum material and a catalytic component loaded on the catalytic carrier, and the catalytic component is composed of a transition metal and a rare earth metal.

[0126] The transition metals in this embodiment are Fe and Mn, and the transition metals account for 10.0% of the total mass of the catalyst in terms of oxides; the rare earth metals are lanthanum and cerium.

[0127] The composite porous silicon-aluminum material of this embodiment is in the form of nanosheets, with a silicon oxide content of 9wt% and a specific surface area of ​​900m 2 / g.

[0128] The preparation method of the catalyst carrier of this embodiment comprises the following steps:

[0129] S1. preparing an impregnation solution containing a catalytic component;

[0130] S2, contacting gibbsite with sodium hydroxide at 130° C. for 18 hours to obtain a sodium aluminate solution;

[0131] S3, adding the sodium aluminate solution dropwise into the aluminum sulfate solution under stirring;

[0132] S4, adding sodium aluminate solution, aluminum sulfate solution and water glass dropwise to the suspension obtained in step S3 under stirring;

[0133] S5, crystallizing the product obtained in step S4 at 95° C. for 15 h;

[0134] S6. Filter the crystallized product obtained in step S5, and wash the filtered solid with deionized water and dry it at a drying temperature of 115° C. to obtain a catalytic carrier.

[0135] S7. Immerse the catalyst carrier prepared in S6 in the impregnation solution prepared in S1 for 35 minutes.

[0136] S8. Wash, dry, calcine at high temperature, and cool under inert gas the porous silicon-alumina carrier loaded with multiple metals obtained in S7 to prepare an ozone catalyst.

[0137] The mass concentration of the catalytic component contained in the impregnation solution in S1 of this embodiment is 3wt% in terms of metal; the molar ratio of Na / Al of sodium hydroxide to gibbsite in S2 is 3:1, and the concentration of the aluminum sulfate solution in S3 is 0.6mol / kg.

[0138] In S8 of this embodiment, the drying temperature is 75° C., the high temperature calcination operation is performed at 550° C. for 4 h; and the inert gas is nitrogen or argon.

[0139] Comparative Example 1.

[0140] The difference from Example 3 is that activated carbon is used instead of the porous silicon-aluminum material.

[0141] Comparative Example 2.

[0142] The difference from Example 3 is that no transition metal is added to the catalytic component.

[0143] Comparative Example 3.

[0144] The difference from Example 3 is that no rare earth metal is added to the catalytic component.

[0145] Comparative Example 4.

[0146] The difference from Example 3 is that the concentration of aluminum sulfate is changed to 1.2 mol / kg.

[0147] Comparative Example 5.

[0148] The difference from Example 3 is that the cooling in S8 is not performed under an inert gas.

[0149] The ozone catalysts prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests.

[0150] A phenol-formaldehyde (1:1) solution was used as raw material, the catalyst was loaded into a bubbling bed reactor, and ozone was used as an oxidizing medium for intermittent treatment. The COD of the phenol-formaldehyde solution was 226 mg / L.

[0151] The treatment conditions were normal temperature and pressure, 50 g catalyst dosage, 500 mL leachate, 9.7 g / m 3 ozone dosage, and 30 min ventilation time.

[0152] It can be seen from Examples 1-3 that after the novel ozone oxidant of the present invention is used to treat the leachate, the removal rate of a certain phenol-formaldehyde in the leachate reaches more than 90%;

[0153] It can be seen from Comparative Examples 1-5 that although the removal rate of the new ozone oxidant prepared by Comparative Examples 1-5 reaches more than 80%, its removal rate is not as high as that of the new ozone oxidant of the present invention.

[0154] The innovation of the present invention is:

[0155] The process flow of the present invention is fully enclosed and pressurized, without the risk of ozone leakage, and is safe and environmentally friendly. Micro-nano ozone bubble generation technology is used when treating the leachate, and the ozone utilization rate reaches more than 96%, and the tail gas has basically no ozone smell. At the same time, ozone catalysts are used in the first oxidation reaction column and the second oxidation reaction column, and the catalytic carrier is made of composite porous silicon-aluminum material, and transition metals and rare earth metals are used as catalytic components. Multi-metal oxide composite ozone catalysis not only has strong catalytic activity, but also can construct catalytic active centers in nanopores. The microenvironment in which it is located can have a strong limiting effect on the physical and chemical state of the catalytic system, and the catalytic efficiency is further improved, so as to specifically remove the difficult-to-degrade characteristic organic pollutants in the landfill leachate, overcome the problem of easy passivation and deactivation of conventional ozone catalysts, have a long service life, and enhance the efficiency of catalytic ozone oxidation.

[0156] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0157] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A landfill leachate oxidation treatment device, characterized in that: It includes an ozone generator, two micro-nano bubble generators, a stabilization column, a No. 1 catalytic reaction column, a No. 2 catalytic reaction column, and an MNR biochemical reaction system; The treatment process of the landfill leachate oxidation treatment device comprises the following steps: Step 1: adding a coagulant and a coagulant aid to the landfill leachate concentrate to perform coagulation and precipitation to obtain a primary clear liquid; Step 2: Turn on the ozone generator. After the ozone generator can stably produce ozone, open the gas control valve between the ozone generator and the micro-nano bubble generator to allow the ozone to stably enter the micro-nano bubble generator. Step 3: Start the micro-nano bubble generator, inject the primary clear liquid in step 1 into the micro-nano bubble generator through the liquid inlet pipe, and the leachate containing ozone micro-nano bubbles enters the stabilization column through the liquid outlet pipe of the micro-nano bubble generator, and fully reacts to obtain the secondary clear liquid; Step 4: Under the action of pressure, the secondary clear liquid enters the bottom of the No. 1 catalytic reaction column through the pipeline at the top of the stabilizing column, and at the same time, another micro-nano bubble generator generates bubbles inside the No. 1 catalytic reaction column, so that the secondary clear liquid fully reacts with the ozone catalyst inside the No. 1 catalytic reaction column to obtain a tertiary clear liquid; Step 5: Under the action of pressure, the third-level clear liquid enters the bottom of the second catalytic reaction column through the pipeline at the top of the first catalytic reaction column, and reacts with the ozone catalyst in the second catalytic reaction column to obtain a fourth-level clear liquid; Step 6: Under the action of pressure, the fourth-stage clear liquid enters from the top of the MNR biochemical reaction system through the pipeline at the top of the No. 2 catalytic reaction column, and at the same time, the ozone generator is connected with the pipeline between the No. 2 catalytic reaction column and the MNR biochemical reaction system through the pipeline, so that the fourth-stage clear liquid and ozone react again and enter the MNR biochemical reaction system at the same time, and finally discharged from the drain port of the MNR biochemical reaction system; The ozone catalyst is composed of a catalytic carrier and a catalytic component made of a composite porous silicon-aluminum material, and the catalytic component is composed of a transition metal and a rare earth metal; The transition metal is one or more of Fe, Cu, Mn, Ti, and Zn, and the transition metal accounts for 0.1%-20.0% of the total mass of the catalyst in terms of oxide; the rare earth metal is one or more of lanthanum, cerium, praseodymium, and neodymium; The composite porous silicon-aluminum material is in the form of nanosheets, has a silicon oxide content of 1-20wt%, and a specific surface area of ​​800-1000m 2 / g; The method for preparing the catalyst carrier comprises the following steps: S1. preparing an impregnation solution containing a catalytic component; S2, contacting gibbsite with sodium hydroxide at 110-150° C. for 12-24 hours to obtain a sodium aluminate solution; S3, adding the sodium aluminate solution dropwise into the aluminum sulfate solution under stirring; S4, adding sodium aluminate solution, aluminum sulfate solution and water glass dropwise to the suspension obtained in step S3 under stirring; S5, crystallizing the product obtained in step S4 at a temperature of 50-140° C. for 6-24 hours; S6, filtering the crystallized product obtained in step S5, and washing the filtered solid with deionized water and drying it at a drying temperature of 60-170° C. to obtain a catalytic carrier; S7, impregnating the catalyst carrier prepared in S6 into the impregnation solution prepared in S1 for 30-40 minutes; S8, washing, drying, high-temperature calcining, and cooling under an inert gas the porous silicon-alumina carrier loaded with multiple metals obtained in S7 to prepare an ozone catalyst; The coagulant in step 1 includes any one of polyferric sulfate and polyaluminium chloride, and the coagulant aid is polyacrylamide; The amount of coagulant added is 0.1-2 kg / m 3 The amount of the coagulant added is 0.01-0.5 kg / m 3 ; The flow rate of ozone in step 2 is 1.5-2.0 L / min, and the flow rate of filtrate into the micro-nano bubble generator in step 3 is 20-30 L / min; The mass concentration of the catalytic component contained in the impregnation solution in S1 is 1wt%-5wt% in terms of metal; the molar ratio of Na / Al of sodium hydroxide to gibbsite in S2 is (2-5):1, and the concentration of the aluminum sulfate solution in S3 is 0.1-1 mol / kg; The drying temperature in S8 is 50-100° C., and the high temperature calcination operation is performed at 500-600° C. for 3-5 hours; the inert gas is nitrogen or argon.

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