A method for treating landfill leachate concentrate

Abstract

The present invention provides a method for treating landfill leachate concentrate, comprising the following steps: solid-liquid separation, bacterial agent treatment, deamination, electrolytic purification, and electro-photocatalytic oxidation, which effectively reduce the COD in the concentrate, introduce ozone through the deamination membrane, and increase the degradation rate of macromolecular organic pollutants. At the same time, ozone and the free radicals generated by it can also alleviate the pollution of the deamination membrane. The electrolytic purification has a cohesive effect on organic or inorganic pollutants in the wastewater, and separates them from the wastewater, thereby improving the purification effect. The electrolytic water is oxidized by combining electro-photocatalytic oxidation to facilitate the removal of flocculants or oil, effectively degrade a large amount of humus, protein, polysaccharides and other substances, and improve the effluent quality. The present invention combines the characteristics of the landfill leachate concentrate, comprehensively considers economic and environmental benefits, and adopts a specific treatment method to make the concentrate meet the effluent discharge standard, laying a foundation for subsequent concentrate utilization technology.

Description

Technical Field

[0001] The present invention relates to the technical field of environmentally friendly garbage treatment, and in particular to a method for treating garbage leachate concentrate. Background Art

[0002] Landfill leachate membrane filtration concentrate refers to the concentrated liquid retained by nanofiltration (NF) membrane or reverse osmosis (RO) membrane after the landfill leachate is biodegraded by the membrane bioreactor (MBR). The concentrate is generally not biodegradable and cannot be discharged or re-injected into the landfill. It requires centralized treatment. Its main components are humus-like substances, which are brown-black in color, have a high COD, and contain a large amount of inorganic ions. Because it contains various difficult-to-degrade organic and inorganic pollutants, direct discharge will pollute the soil, surface water, ocean, etc.; if discharged into the municipal sewage treatment system, the excessively high total dissolved solids are also not conducive to the growth of activated sludge. Landfill leachate concentrate is obtained by anaerobic fermentation of wastewater generated in the landfill, and then undergoing filtration, disinfection and other process flows.

[0003] For the treatment of landfill leachate concentrate, re-injection technology is currently used to improve the recovery rate and increase the membrane surface flushing flow rate. However, over time, the disadvantages of re-injection have gradually become apparent. Domestic landfills have experienced varying degrees of accumulation of pollutants, increased permeability and conductivity, decreased membrane water production rate, and even increased conductivity leading to membrane filtration failure. The use of membrane technology for landfill leachate is relatively common, but the membrane cost is high and the distillation flux is small.

[0004] The concentrated liquid obtained by filtration of landfill leachate using submerged evaporation membranes typically contains a high proportion of chloride ions. Furthermore, chloride ions can be extremely corrosive to metal materials when exposed to temperatures exceeding 70°C. This makes equipment corrosion a key limitation in high-temperature evaporation of landfill leachate or concentrate. Therefore, research into efficient methods for degrading landfill leachate concentrate is urgently needed to address this issue. Summary of the Invention

[0005] In view of this, the present invention proposes a method for treating landfill leachate concentrate to solve the above problems.

[0006] The technical solution of the present invention is achieved as follows: A method for treating landfill leachate concentrate comprises the following steps:

[0007] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for standing for solid-liquid separation, and the sludge is recovered to obtain concentrated liquid level I;

[0008] S2, microbial agent treatment: Add a composite microbial agent to the concentrate of level I at an amount of 100-500 mg / L, and allow to stand for 2-5 hours at normal pressure and temperature to obtain concentrate of level II; reduce BOD5 and COD in the concentrate;

[0009] S3, deamination: The concentrated liquid of level I is fed into the deamination membrane, and ozone is introduced at the same time. The ozone introduction rate is 1.5-2.3 mg / L to obtain deammonium water and ammonium sulfate solution, and the ammonium sulfate solution is recycled. The ozone is introduced into the deamination membrane to deaminize and catalyze the oxidation of ozone to generate hydroxyl radicals. At the same time, the mass transfer of ozone is enhanced, and the degradation rate of large molecular organic pollutants is increased during the treatment process. At the same time, ozone and the free radicals it produces can also alleviate the pollution of the deamination membrane and improve the effluent quality.

[0010] S4. Electrolytic purification: The deammonium water is purified by electrolysis at a current density of 250-350A / dm 2 , obtaining electrolyzed water; after electrolysis of deammonified water, hydrogen ions or hydroxide ions are generated, which are further hydrolyzed with metal cations to form metal hydrides with surface charge and strong adsorption, which have a cohesive effect on organic or inorganic pollutants in wastewater and separate them from the wastewater, thereby improving the purification effect;

[0011] S5. Electro-photocatalytic oxidation: The electrolyzed water is added to an electrocatalytic device for oxidation treatment, and a nano-photocatalyst is added for ultraviolet light catalysis to obtain discharge water for discharge; the electrolyzed water produces hydrogen and oxygen, forming fine bubbles, which make flocs or oil adhere to the bubbles and are easy to remove, effectively degrading a large amount of humus, protein or polysaccharide and other substances; photocatalytic oxidation attacks the quinone structure, azo structure and other chromophores in the humus substances in the concentrate, destroying the benzene ring or nitrogen-nitrogen double bond structure in the chromophore, which is beneficial to the removal of COD, chroma, copper ions and lead ions in the concentrate.

[0012] Furthermore, the composite bacterial agent includes the following raw materials in parts by weight: 2-10 parts of denitrifying Thiobacillus, 3-8 parts of Rhodopseudomonas, 1.8-3.5 parts of Lactobacillus acidophilus, and 0.9-2.2 parts of calcoacetic acid Acinetobacter.

[0013] Furthermore, the number of viable bacteria of Thiobacillus denitrificans was greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, the number of viable Lactobacillus acidophilus was 1.2-1.6×10 9 cfu / mL, viable bacteria count of calcoacetic acid Acinetobacter 4-10×10 8 cfu / mL.

[0014] Furthermore, the deamination membrane is a PTFE deamination nitrogen membrane with an average membrane flux of 100-120 L / (m2 h); A hydrophobic PTFE hollow fiber microporous membrane is used to separate the ammonia nitrogen-containing wastewater from the acid absorption liquid. The ammonia nitrogen in the concentrate is dissociated into gaseous NH3, which can pass through the micropores on the PTFE membrane wall of the membrane.

[0015] Furthermore, the voltage of the electrocatalytic oxidation of S5 is 18-25V, the current is 1-3A, and the time is 3-5h.

[0016] Furthermore, the nano-photocatalyst of S5 is a nano-solid solution composed of titanium dioxide, zinc oxide and graphene in a mass ratio of 1-3:0.3-1.8:5.

[0017] Furthermore, the wavelength of ultraviolet light emitted by the ultraviolet photocatalysis of S5 is 250-256nm, and the current density is 400-600A / m 2 , the flow rate of the liquid passing through the electrode is 1-4m / s.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention purifies the landfill leachate membrane filtration concentrate by a specific treatment method. The composite bacterial agent selects specific bacterial species and combines them in proportion, which can effectively reduce the COD in the concentrate. After the deamination membrane deaminates, deammoniated water is formed. Ozone is introduced into the deamination membrane to play a deamination role and catalytically oxidize ozone to generate hydroxyl free radicals, while strengthening the mass transfer of ozone, thereby increasing the degradation rate of large molecular organic pollutants during the treatment process. At the same time, ozone and the free radicals generated by it can also alleviate the pollution of the deamination membrane and improve the effluent quality; the deammoniated water is electrolytically purified to have a cohesive effect on organic or inorganic pollutants in the wastewater; and the electrolytic water is oxidized by combining electric-photocatalytic oxidation to remove flocculants or oil, and effectively degrade a large amount of humus, protein or polysaccharide and other substances. At the same time, the use of nano-photocatalysts and the adjustment of their proportions can significantly remove COD, chromaticity and metal ions in the concentrate and reduce the conductivity in the concentrate.

[0020] The present invention combines the characteristics of garbage leachate concentrate, integrates economic and environmental benefits, and adopts a specific treatment method to make the concentrate meet the effluent discharge standard, laying the foundation for subsequent concentrate utilization technology. DETAILED DESCRIPTION

[0021] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0022] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0023] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0024] Example 1

[0025] A method for treating landfill leachate concentrate comprises the following steps:

[0026] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for standing solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain concentrated liquid level I;

[0027] S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated liquid I. The composite bacterial agent includes the following raw materials in parts by weight: 2 parts of denitrifying Thiobacillus, 3 parts of Rhodopseudomonas, 1.8 parts of Lactobacillus acidophilus, and 0.9 parts of Acinetobacter calcoaceticus. The number of viable bacteria of denitrifying Thiobacillus is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, and the number of viable Lactobacillus acidophilus was 1.2×10 9 cfu / mL, viable bacteria count of Acinetobacter calcoaceticus 4×10 8 cfu / mL, the input amount is 100 mg / L, and it is left to stand for 2 hours at normal pressure and temperature to obtain a concentrated solution of level II;

[0028] S3, deamination: the concentrated liquid is sent to the deamination membrane, which is a PTFE deamination nitrogen membrane with an average membrane flux of 100L / (m 2 h), while introducing ozone at a rate of 1.5 mg / L to obtain deammonium water and ammonium sulfate solution, which is then recycled;

[0029] S4, electrolytic purification: the above deammonium water is purified by electrolysis with a current density of 250A / dm 2 , obtaining electrolyzed water;

[0030] S5. Electro-photocatalytic oxidation: The electrolyzed water is added to an electrocatalytic device for oxidation treatment. The voltage of the electrocatalytic oxidation is 18V, the current is 1A, and the time is 3h. A nano-photocatalyst is added for ultraviolet photocatalysis. The nano-photocatalyst is a nano-solid solution composed of titanium dioxide, zinc oxide and graphene in a mass ratio of 1:0.3:5. The ultraviolet light wavelength emitted by the ultraviolet photocatalysis is 250nm, and the current density is 400A / m 2 The flow rate of the liquid passing through the electrode is 1m / s, and the discharge water is discharged.

[0031] Example 2

[0032] A method for treating landfill leachate concentrate comprises the following steps:

[0033] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain the concentrated liquid I

[0034] S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated liquid I. The composite bacterial agent includes the following raw materials in parts by weight: 10 parts of denitrifying Thiobacillus, 8 parts of Rhodopseudomonas, 3.5 parts of Lactobacillus acidophilus, and 2.2 parts of Acinetobacter calcoaceticus. The number of viable bacteria of denitrifying Thiobacillus is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, and the number of viable Lactobacillus acidophilus was 1.6×10 9 cfu / mL, viable bacteria count of Acinetobacter calcoaceticus 10×10 8 cfu / mL, the input amount is 500mg / L, and it is left to stand for 5h at normal pressure and temperature to obtain a concentrated solution of level II;

[0035] S3, deamination: the concentrated liquid is sent to the deamination membrane, which is a PTFE deamination nitrogen membrane with an average membrane flux of 120L / (m 2 h), while introducing ozone at a rate of 2.3 mg / L to obtain deammonium water and ammonium sulfate solution, which is then recycled;

[0036] S4, electrolytic purification: the above deammonium water is purified by electrolysis with a current density of 350A / dm 2 , obtaining electrolyzed water;

[0037] S5. Electro-photocatalytic oxidation: The electrolyzed water was added to an electrocatalytic device for oxidation treatment. The voltage of the electrocatalytic oxidation was 25V, the current was 3A, and the time was 5h. A nano-photocatalyst was added for ultraviolet photocatalysis. The nano-photocatalyst was a nano-solid solution composed of titanium dioxide, zinc oxide, and graphene in a mass ratio of 3:1.8:5. The wavelength of ultraviolet light emitted by the ultraviolet photocatalysis was 256nm, and the current density was 600A / m 2 The flow rate of the liquid passing through the electrode is 4m / s, and the discharge water is discharged.

[0038] Example 3

[0039] A method for treating landfill leachate concentrate comprises the following steps:

[0040] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain the concentrated liquid I

[0041] S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated liquid I. The composite bacterial agent includes the following raw materials in parts by weight: 6 parts of denitrifying Thiobacillus, 5 parts of Rhodopseudomonas, 2.5 parts of Lactobacillus acidophilus, and 1.5 parts of Acinetobacter calcoaceticus. The number of viable bacteria of denitrifying Thiobacillus is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×108 cfu / mL, and the number of viable Lactobacillus acidophilus was 1.4×10 9 cfu / mL, viable bacteria count of Acinetobacter calcoaceticus 7×10 8 cfu / mL, the input amount is 300 mg / L, and it is left to stand for 3 hours at normal pressure and temperature to obtain a concentrated solution of level II;

[0042] S3, deamination: the concentrated liquid is sent to the deamination membrane, which is a PTFE deamination nitrogen membrane with an average membrane flux of 110L / (m 2 h), while introducing ozone at a rate of 1.9 mg / L to obtain deammonium water and ammonium sulfate solution, which is then recycled;

[0043] S4, electrolytic purification: the above deammonium water is purified by electrolysis with a current density of 300A / dm 2 , obtaining electrolyzed water;

[0044] S5. Electro-photocatalytic oxidation: The electrolyzed water is added to an electrocatalytic device for oxidation treatment. The voltage of the electrocatalytic oxidation is 22V, the current is 2A, and the time is 3-5h. A nano-photocatalyst is added for ultraviolet photocatalysis. The nano-photocatalyst is a nano-solid solution composed of titanium dioxide, zinc oxide and graphene with a mass ratio of 2:1.2:5. The ultraviolet light wavelength emitted by the ultraviolet photocatalysis is 254nm, and the current density is 500A / m 2 The flow rate of the liquid passing through the electrode is 3m / s, and the discharge water is discharged.

[0045] Example 4

[0046] A method for treating landfill leachate concentrate comprises the following steps:

[0047] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain the concentrated liquid I

[0048] S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated liquid I. The composite bacterial agent includes the following raw materials in parts by weight: 2 parts of denitrifying Thiobacillus, 3 parts of Rhodopseudomonas, 1.8 parts of Lactobacillus acidophilus, and 0.9 parts of Acinetobacter calcoaceticus. The number of viable bacteria of denitrifying Thiobacillus is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, and the number of viable Lactobacillus acidophilus was 1.4×10 9 cfu / mL, viable bacteria count of Acinetobacter calcoaceticus 7×10 8 cfu / mL, the input amount is 300 mg / L, and it is left to stand for 3 hours at normal pressure and temperature to obtain a concentrated solution of level II;

[0049] S3, deamination: the concentrated liquid is sent to the deamination membrane, which is a PTFE deamination nitrogen membrane with an average membrane flux of 110L / (m 2 h), while introducing ozone at a rate of 1.9 mg / L to obtain deammonium water and ammonium sulfate solution, which is then recycled;

[0050] S4, electrolytic purification: the above deammonium water is purified by electrolysis with a current density of 300A / dm 2 , obtaining electrolyzed water;

[0051] S5. Electro-photocatalytic oxidation: The electrolyzed water is added to an electrocatalytic device for oxidation treatment. The voltage of the electrocatalytic oxidation is 22V, the current is 2A, and the time is 3-5h. A nano-photocatalyst is added for ultraviolet photocatalysis. The nano-photocatalyst is a nano-solid solution composed of titanium dioxide, zinc oxide and graphene with a mass ratio of 2:1.2:5. The ultraviolet light wavelength emitted by the ultraviolet photocatalysis is 254nm, and the current density is 500A / m 2 The flow rate of the liquid passing through the electrode is 3m / s, and the discharge water is discharged.

[0052] Example 5

[0053] A method for treating landfill leachate concentrate comprises the following steps:

[0054] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain the concentrated liquid I

[0055] S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated liquid I. The composite bacterial agent includes the following raw materials in parts by weight: 10 parts of denitrifying Thiobacillus, 8 parts of Rhodopseudomonas, 3.5 parts of Lactobacillus acidophilus, and 2.2 parts of Acinetobacter calcoaceticus. The number of viable bacteria of denitrifying Thiobacillus is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, and the number of viable Lactobacillus acidophilus was 1.4×10 9 cfu / mL, viable bacteria count of Acinetobacter calcoaceticus 7×10 8 cfu / mL, the input amount is 300 mg / L, and it is left to stand for 3 hours at normal pressure and temperature to obtain a concentrated solution of level II;

[0056] S3, deamination: the concentrated liquid is sent to the deamination membrane, which is a PTFE deamination nitrogen membrane with an average membrane flux of 110L / (m 2 h), while introducing ozone at a rate of 1.9 mg / L to obtain deammonium water and ammonium sulfate solution, which is then recycled;

[0057] S4, electrolytic purification: the above deammonium water is purified by electrolysis with a current density of 300A / dm 2 , obtaining electrolyzed water;

[0058] S5. Electro-photocatalytic oxidation: The electrolyzed water is added to an electrocatalytic device for oxidation treatment. The voltage of the electrocatalytic oxidation is 22V, the current is 2A, and the time is 3-5h. A nano-photocatalyst is added for ultraviolet photocatalysis. The nano-photocatalyst is a nano-solid solution composed of titanium dioxide, zinc oxide and graphene with a mass ratio of 2:1.2:5. The ultraviolet light wavelength emitted by the ultraviolet photocatalysis is 254nm, and the current density is 500A / m 2 The flow rate of the liquid passing through the electrode is 3m / s, and the discharge water is discharged.

[0059] Example 6

[0060] The difference between this embodiment and embodiment 3 is that the composite bacterial agent comprises the following raw materials in parts by weight: 1 part of denitrifying Thiobacillus, 10 parts of Rhodopseudomonas, 5 parts of Lactobacillus acidophilus, and 1 part of Acinetobacter calcoaceticus.

[0061] Example 7

[0062] The difference between this embodiment and embodiment 3 is that the composite bacterial agent does not contain Acinetobacter calcoaceticus.

[0063] Example 8

[0064] The difference between this embodiment and embodiment 3 is that the nano-photocatalyst is a nano-solid solution composed of titanium dioxide, zinc oxide and graphene in a mass ratio of 1:3:1.

[0065] 1. Test Verification

[0066] Eight groups of experiments were set up corresponding to the treatment methods of Examples 1-8 above, and the pH, COD, NH3-N, TN, and NO of the landfill leachate concentrate obtained after treatment were analyzed. 3- -N, BOD5 / COD and color.

[0067] (1) Raw water quality: The landfill leachate membrane concentrate was obtained from the RO membrane concentrate of the leachate from a landfill in Hainan Province. The water quality analysis is shown in Table 1:

[0068] Table 1 Water quality analysis of garbage leachate concentrate

[0069]

[0070]

[0071] (2) Test method:

[0072]

[0073] (3) Reduction rate % = (raw water index concentration - treated index concentration) / raw water concentration × 100

[0074] (4) Test results:

[0075]

[0076] From the above results, it can be seen that the treatment method of the present invention effectively purifies the landfill leachate concentrate. Compared with Examples 1-5 and Examples 6 and 7, the composite bacterial agent selects specific bacterial species and combines them in proportion, which can effectively reduce the COD in the concentrate. Compared with Example 1-5 and Example 8, the use of a specific proportion in the nano-photocatalyst can significantly remove the COD, color, and metal ions in the concentrate and reduce the conductivity of the concentrate; among them, the effect achieved in Example 3 is more significant.

[0077] (5) Comparison of BOD5 / COD inlet and outlet concentration changes

[0078] Water ingress Water Example 1 0.03 0.34 Example 2 0.03 0.35 Example 3 0.03 0.33 Example 4 0.03 0.30 Example 5 0.03 0.29 Example 6 0.03 0.16 Example 7 0.03 0.15 Example 8 0.03 0.28

[0079] The results of Examples 6 and 7 in the above table show that by selecting specific bacterial species and combining them in proportion, the biodegradability of the concentrate is greatly improved, which is beneficial for subsequent biochemical treatment.

[0080] The following comparative tests are set up based on the above results, as follows:

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 3 is that the concentrated liquid in step S3 is fed into the deamination membrane at level I without introducing ozone. Specifically, the method for treating the concentrated liquid of landfill leachate comprises the following steps:

[0083] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain the concentrated liquid I

[0084] S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated liquid I. The composite bacterial agent includes the following raw materials in parts by weight: 6 parts of denitrifying Thiobacillus, 5 parts of Rhodopseudomonas, 2.5 parts of Lactobacillus acidophilus, and 1.5 parts of Acinetobacter calcoaceticus. The number of viable bacteria of denitrifying Thiobacillus is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, and the number of viable Lactobacillus acidophilus was 1.4×10 9 cfu / mL, viable bacteria count of Acinetobacter calcoaceticus 7×10 8 cfu / mL, the input amount is 300 mg / L, and it is left to stand for 3 hours at normal pressure and temperature to obtain a concentrated solution of level II;

[0085] S3, deamination: the concentrated liquid is sent to the deamination membrane, which is a PTFE deamination nitrogen membrane with an average membrane flux of 110L / (m 2 h), obtaining deammonium water and ammonium sulfate solution, and recycling the ammonium sulfate solution;

[0086] S4, electrolytic purification: the above deammonium water is purified by electrolysis with a current density of 65A / dm 2 , obtaining electrolyzed water;

[0087] S5. Electro-photocatalytic oxidation: The electrolyzed water is added to an electrocatalytic device for oxidation treatment. The voltage of the electrocatalytic oxidation is 22V, the current is 2A, and the time is 3-5h. A nano-photocatalyst is added for ultraviolet photocatalysis. The nano-photocatalyst is a nano-solid solution composed of titanium dioxide, zinc oxide and graphene with a mass ratio of 2:1.2:5. The ultraviolet light wavelength emitted by the ultraviolet photocatalysis is 254nm, and the current density is 500A / m 2 The flow rate of the liquid passing through the electrode is 3m / s, and the discharge water is discharged.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 3 is that only electrocatalytic oxidation is performed in S5. Specifically, the method for treating landfill leachate concentrate comprises the following steps:

[0090] S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain the concentrated liquid I

[0091] S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated liquid I. The composite bacterial agent includes the following raw materials in parts by weight: 6 parts of denitrifying Thiobacillus, 5 parts of Rhodopseudomonas, 2.5 parts of Lactobacillus acidophilus, and 1.5 parts of Acinetobacter calcoaceticus. The number of viable bacteria of denitrifying Thiobacillus is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, and the number of viable Lactobacillus acidophilus was 1.4×10 9 cfu / mL, viable bacteria count of Acinetobacter calcoaceticus 7×10 8 cfu / mL, the input amount is 300 mg / L, and it is left to stand for 3 hours at normal pressure and temperature to obtain a concentrated solution of level II;

[0092] S3, deamination: the concentrated liquid is sent to the deamination membrane, which is a PTFE deamination nitrogen membrane with an average membrane flux of 110L / (m 2 h), while introducing ozone at a rate of 1.9 mg / L to obtain deammonium water and ammonium sulfate solution, which is then recycled;

[0093] S4, electrolytic purification: the above deammonium water is purified by electrolysis with a current density of 65A / dm 2 , obtaining electrolyzed water;

[0094] S5. Electrocatalytic oxidation: Add the electrolyzed water to the electrocatalytic device for oxidation treatment. The voltage of the electrocatalytic oxidation is 22V, the current is 2A, and the time is 3-5h. The discharged water is discharged.

[0095] The comparative example was measured according to the above test method, and the results were as follows:

[0096]

[0097]

[0098] Compared with Comparative Example 1, in Example 3, ozone is introduced into the deamination membrane, which can catalyze the oxidation of ozone to generate hydroxyl radicals, and at the same time enhance the mass transfer of ozone, thereby increasing the degradation rate of macromolecular organic pollutants during the treatment process and improving the effluent quality; in Example 3, compared with Comparative Example 2, through the combination of electro-photocatalytic oxidation of the present invention, electrocatalytic oxidation cooperates with each other through various oxidation reactions, and the organic matter is completely decomposed into carbon dioxide and water. After the electrocatalytic oxidation, a nano-photocatalyst is added for photocatalysis, which can degrade a large amount of humus, protein or polysaccharide and other substances, and at the same time attack the quinone structure, azo structure and other chromophores in the humus substances in the concentrate, destroy the benzene ring or nitrogen-nitrogen double bond structure in its chromophore, which is beneficial to the COD, chromaticity and metal ions in the concentrate. It has a good removal effect.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for treating landfill leachate concentrate, characterized by: The following steps are involved: S1, solid-liquid separation: the concentrated liquid intercepted by the membrane is sent to the sedimentation tank for standing solid-liquid separation, and the sludge is enriched, concentrated and recovered to obtain concentrated liquid level I; S2. Bacterial agent treatment: Add a composite bacterial agent to the concentrated solution of level I at an amount of 100-500 mg / L, and allow to stand for 2-5 hours at normal pressure and temperature to obtain concentrated solution of level II; S3, deamination: The concentrated liquid of level II is sent to the deamination membrane, and ozone is introduced at the same time. The ozone introduction rate is 1.5~2.3mg / L to obtain deammonium water and ammonium sulfate solution, and the ammonium sulfate solution is recycled; S4. Electrolytic purification: The deammonium water is purified by electrolysis at a current density of 250-350A / dm 2 , obtaining electrolyzed water; S5. Electro-photocatalytic oxidation: adding the electrolyzed water to an electrocatalytic device for oxidation treatment, adding a nano-photocatalyst for ultraviolet photocatalysis, and obtaining discharge water for discharge; The composite bacterial agent S2 is composed of the following raw materials in parts by weight: 2-10 parts of denitrifying Thiobacillus, 3-8 parts of Rhodopseudomonas, 1.8-3.5 parts of Lactobacillus acidophilus, and 0.9-2.2 parts of Acinetobacter calcoaceticus; The deamination membrane of S3 is a PTFE deamination nitrogen membrane with an average membrane flux of 100-120L / (m 2 h); The nano photocatalyst of S5 is composed of a nano solid solution composed of titanium dioxide, zinc oxide and graphene in a mass ratio of 1-3:0.3-1.8:

5.

2. The method for treating landfill leachate concentrate according to claim 1, wherein: The number of viable bacteria of Thiobacillus denitrificans is greater than 3.5×10 8 cfu / mL, the number of viable Rhodopseudomonas is greater than 2×10 8 cfu / mL, the number of viable Lactobacillus acidophilus was 1.2-1.6×10 9 cfu / mL, viable bacteria count of calcoacetic acid Acinetobacter 4-10×10 8 cfu / mL.

3. The method for treating landfill leachate concentrate according to claim 1, wherein: The voltage of the electrocatalytic oxidation of S5 is 18-25V, the current is 1-3A, and the time is 3-5h.

4. The method for treating landfill leachate concentrate according to claim 1, wherein: The wavelength of ultraviolet light emitted by the ultraviolet photocatalysis of S5 is 250-256nm, and the current density is 400-600A / m 2 , the flow rate of the liquid passing through the electrode is 1-4m / s.

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