A method for treating and deodorizing kitchen wastewater

Abstract

The application discloses a kind of kitchen wastewater treatment deodorization methods, belong to wastewater treatment field.The wastewater treatment method includes oil-water separation, pH adjustment, nitrogen removal and deodorization of stripping tower, activated carbon adsorption, biochemical treatment and flocculation treatment, wherein in nitrogen removal and deodorization link of stripping tower, adjusted wastewater is input from the top of stripping tower, falls into the lower part of stripping tower by spraying device, and air is blown upward by the air port in the lower part of stripping tower, can transfer free ammonia in wastewater from liquid phase to gas phase, and input atomized deodorization liquid inward, contact each other between spraying wastewater, maximize the contact area between deodorization liquid and wastewater, accelerate deodorization liquid to neutralize and decompose odorant in wastewater, decomposed and discharged with air, finally, activated carbon packing layer is set at the bottom end of stripping tower, adsorb impurities in wastewater, intercept residual deodorization liquid, reduce subsequent processing load and adverse effect, improve the efficiency and effect of overall wastewater treatment deodorization.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and in particular to a method for deodorizing kitchen wastewater. Background Technology

[0002] Kitchen wastewater contains high concentrations of organic matter such as grease, protein, and starch, as well as suspended solids and putrefactive substances. Its COD value is extremely high, and its water quality fluctuates greatly. It is prone to fermentation, producing foul-smelling gases. Direct discharge of untreated kitchen wastewater can cause environmental risks such as eutrophication, sewer blockage, and air pollution. The accompanying foul odor poses a dual threat to the surrounding environment and human health.

[0003] For the treatment of kitchen wastewater, physicochemical and biological methods are commonly used. However, physical adsorption processes are insufficient in removing dissolved odor substances, chemical oxidation has high dosage costs, and biological treatment has long treatment cycles, leading to decreased deodorization efficiency. In the process of treating kitchen wastewater, if deodorization measures are ineffective, it may exacerbate air pollution, affecting the surrounding environment and people. Untreated odors, along with leaked or overflowing wastewater, can seep into water bodies, causing eutrophication and depletion of dissolved oxygen, thus threatening the survival of aquatic life.

[0004] Therefore, there is an urgent need to develop a method for treating kitchen wastewater that can synergistically remove pollutants and odors, is highly resistant to impact, and has low operation and maintenance costs, so as to achieve effective wastewater treatment. Summary of the Invention

[0005] This invention provides a method for deodorizing kitchen wastewater, which can solve the problem that pollutants and odors are difficult to remove simultaneously and efficiently in the existing kitchen wastewater treatment process.

[0006] A method for treating and deodorizing kitchen wastewater includes the following process steps:

[0007] S1. The kitchen wastewater is fed into the oil-water separation equipment for oil-water separation, and then the wastewater obtained after separation is settled to remove the sludge generated by the sedimentation.

[0008] S2. Add alkali to the wastewater obtained after sedimentation to adjust the pH value of the wastewater to 9-11;

[0009] S3. The adjusted wastewater is fed into the top of the stripping tower and falls into the bottom of the stripping tower through the spray device; there is an activated carbon filling layer at the bottom of the stripping tower and air outlets are set to blow air upwards. At the same time, deodorizing liquid is fed into the tower through the dosing system and the high-pressure atomization system, and the generated gas is discharged.

[0010] S4. The wastewater passing through the stripping tower enters the A / O biological treatment unit for biological treatment, and then the solid impurities in the wastewater are removed by sedimentation;

[0011] S5. Finally, add flocculant to the wastewater, separate the solid and liquid, and discharge it after disinfection.

[0012] Preferably, during the input of the deodorizing liquid, the diameter of the atomized droplets of the deodorizing liquid is controlled to be ≤0.04mm.

[0013] Preferably, the alkali includes one or more of sodium hydroxide, calcium oxide, and calcium hydroxide.

[0014] Preferably, the flocculant includes any one of iron salts, aluminum salts, and polymeric flocculants.

[0015] By adopting the above technical solution, the pH value of the kitchen wastewater after oil-water separation is first adjusted. Since the kitchen wastewater contains a large amount of ammonia nitrogen, which is an important substance causing eutrophication of water bodies and environmental pollution, alkali can be added to remove the ammonia nitrogen from the wastewater by first removing it from the ammonium ion NH4+. + The conversion into free ammonia can provide favorable conditions for subsequent wastewater treatment steps.

[0016] The regulated wastewater is then fed into the stripping tower from above, while air is blown upwards from below, creating a counter-current contact with the wastewater. The wastewater, after passing through a spray system, is separated into smaller droplets, significantly increasing the contact area with air. Utilizing the concentration difference of ammonia between the liquid and gas phases, free ammonia transfers from the liquid phase to the gas phase, effectively removing free ammonia from the wastewater. Furthermore, the stripping tower is connected to a dosing system and a high-pressure atomization system, allowing the deodorizing liquid to enter the tower in atomized form and come into contact with the sprayed wastewater. This greatly increases the contact area with the wastewater and the odor molecules within it. The active ingredients in the deodorizer decompose hydrogen sulfide and other volatile organic compounds in the wastewater, neutralizing the odor or decomposing them into gases that are discharged with the air, thus effectively removing the wastewater odor.

[0017] Furthermore, an activated carbon packing layer is installed below the stripping tower. The unique structural characteristics of activated carbon—high specific surface area and well-developed microporous structure—do not hinder wastewater discharge while simultaneously adsorbing residual free ammonia and small-molecule impurities remaining in the deodorizing liquid, thereby reducing the load on subsequent treatment processes. Through the synergistic effect of air stripping, atomized deodorization, and the activated carbon packing layer in the stripping tower, efficient removal of free ammonia and odorous substances from wastewater is achieved by utilizing physical mass transfer, chemical reactions, and the adsorption matrix.

[0018] Finally, the wastewater undergoes biological treatment using an A / O (anaerobic / aerobic) biological treatment unit. The aerobic zone in the A / O biological treatment effectively degrades COD and BOD5 in the wastewater, and the synergistic anoxic zone effectively removes nitrogen and phosphorus. Finally, flocculants are added for flocculation treatment to remove colloidal pollutants and large, recalcitrant pollutants, further adsorbing and removing pollutants. Finally, the wastewater is disinfected and discharged as treated wastewater that meets emission standards. The treatment method of this invention can effectively remove pollutants and odor substances from kitchen wastewater, improving pollutant removal efficiency.

[0019] Preferably, the deodorizing liquid is obtained by diluting the deodorizing agent stock solution with water by 20 to 30 times; the deodorizing agent stock solution includes the following raw materials in parts by weight: 3 to 6 parts of wild grass extract, 40 to 50 parts of multi-ionic liquid, 2 to 4 parts of oxidant and 5 to 8 parts of additive.

[0020] Preferably, the wild herb extract includes one or more of the following: wild chrysanthemum extract, wild licorice extract, wild peony extract, wild kudzu flower extract, wild sesame extract, and wild thyme extract.

[0021] Preferably, the multi-ion liquid includes metal ions with a concentration of 400–600 mmol / L; the metal ions include at least two or more of calcium ions, magnesium ions, zinc ions and potassium ions.

[0022] More preferably, the oxidant includes either potassium permanganate or hydrogen peroxide.

[0023] More preferably, the additives include one or more combinations of potassium hydroxide, sodium bicarbonate, sodium carbonate boric acid, tridecyl alcohol polyether-8, sodium tripolyphosphate, sodium phosphate, and ethanolamine.

[0024] Preferably, the deodorant stock solution is prepared according to the following method:

[0025] Preparation of multi-ionic liquids: Soluble metal ion compounds are added sequentially to water, and the mixture is stirred at 30-50°C for 4-8 hours. After standing for 1-2 days, the supernatant is collected and diluted with water 3-5 times to obtain the multi-ionic liquid.

[0026] Preparation of deodorant stock solution: Wild grass extract, oxidant and additives are added sequentially to a multi-ionic liquid and stirred to obtain the deodorant stock solution.

[0027] More preferably, the soluble metal ion compound includes two or more combinations of calcium carbonate, calcium bicarbonate, calcium hydroxide, calcium acetate, magnesium carbonate, magnesium sulfate, zinc acetate, zinc sulfate, zinc gluconate, potassium bicarbonate, potassium hydroxide, and potassium chloride.

[0028] By adopting the above technical solution, the deodorizing liquid of the present invention includes wild grass extract. As a natural plant extract, wild grass extract can enhance the interaction between active substances and malodorous molecules in wastewater after atomization. Wild grass extract is rich in terpenes, tannins, alkaloids and sugars, and can decompose odorous substances through reactions such as acid-base neutralization, oxidation-reduction and esterification. Moreover, the conjugated double bonds in wild grass extract can provide a high-density electron cloud, which is beneficial for attracting and capturing odorous molecules in wastewater. Compared with other plant extracts, wild grass extract has a strong deodorizing ability. In addition to decomposing odorous molecules, it can also synergistically treat free ammonia in wastewater, increasing the denitrification efficiency of wastewater.

[0029] Meanwhile, the deodorizing liquid of the present invention also includes a multi-ionic liquid, which contains a variety of metal ions. The various metal ions have a rich synergistic effect that can quickly capture odor substances that escape from the air and react with odor substances in wastewater to prevent the diffusion of odorous gases. In addition, it contains additives, most of which are alkaline substances, which can better react and decompose odor substances in wastewater such as hydrogen sulfide and free ammonia.

[0030] Metal ions in multi-ion liquids can also act as catalysts to accelerate the dispersion of oxidants. The generated active oxygen can oxidize odor molecules and remove odor substances from wastewater. On the other hand, it can capture and adsorb free ammonia in wastewater, converting it into nitrogen gas for emission. Furthermore, the carbon dioxide produced when active oxygen decomposes organic matter in wastewater reduces the solubility of free ammonia in the wastewater, thereby further increasing the escape rate of free ammonia in the stripping tower and effectively removing ammonia nitrogen pollutants from the wastewater.

[0031] Preferably, the raw material for the activated carbon filling layer includes modified activated carbon; the surface of the modified activated carbon contains carboxyl-amide groups; and the surface of the modified activated carbon is grafted with long-chain alkyl groups.

[0032] By adopting the above technical solutions, the presence of free ammonia in wastewater can be significantly reduced through the liquid-gas mass transfer effect of air and the deodorization treatment of the deodorizing liquid. This also greatly reduces odorous substances and their diffusion. However, residual active substances in the herb extract of the deodorizing liquid or residual metal ions in the multi-ion liquid can affect subsequent wastewater treatment steps. Residual active substances may introduce excessive organic carbon sources during the A / O biological treatment process, affecting the carbon-nitrogen balance of denitrification and leading to a decrease in total nitrogen removal rate. Residual metal ions can affect the activity of nitrifying and denitrifying bacteria, interfering with microbial metabolism and reducing the system's denitrification capacity. Furthermore, in the subsequent flocculation stage, they will compete with flocculants for adsorption sites on the colloidal surface in the wastewater, resulting in decreased settling performance. While an activated carbon packing layer below the stripping tower can adsorb some impurity molecules in the wastewater, its adsorption capacity is poor for non-polar deodorizing liquid residues and metal ions in multi-ion liquids.

[0033] To address the aforementioned issues, the activated carbon filling layer of this invention utilizes modified activated carbon as its raw material. The modified activated carbon contains carboxyl and amide groups on its surface and is also grafted with long-chain alkyl groups. These long-chain alkyl groups enhance the affinity of the activated carbon for residual non-polar small active molecules in the deodorizing liquid through hydrophobic interactions, thereby improving the adsorption capacity of the modified activated carbon for deodorizing liquid residues. Furthermore, the amide groups can bind to some polar small molecules in the deodorizing liquid through hydrogen bonding, further enhancing the adsorption of deodorizing liquid residues.

[0034] The introduction of carboxyl and amide groups can lead to ion exchange or coordination reactions with various metal ions in multi-ion liquids, thereby enhancing the adsorption capacity of modified activated carbon for residual metal ions. The residual metal ions remain in the activated carbon packing layer and will not affect the subsequent treatment process. Moreover, the modified activated carbon has an increased mesoporous ratio, which can improve the adsorption capacity for impurity molecules and improve the removal efficiency and effect of wastewater treatment.

[0035] Preferably, the raw materials for the modified activated carbon include activated carbon, propylene monomers and long-chain alkyl silanes in a mass ratio of 10:(0.5-0.7):(0.1-0.3); the propylene monomers include acrylamide monomers and acrylic acid monomers in a mass ratio of 1:(2-4).

[0036] Preferably, the acrylamide monomer includes one or more combinations of methacrylamide, acrylamide, N,N-dimethylacrylamide and N-hydroxymethylacrylamide; the acrylic monomer includes one or more combinations of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate and methyl methacrylate.

[0037] Preferably, the long-chain alkylsilane includes one or more combinations of octadecyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltriethoxysilane, n-octyltrimethoxysilane, octyltriethoxysilane, and hexyltrimethoxysilane.

[0038] Preferably, the modified activated carbon is prepared according to the following method:

[0039] Pretreatment of activated carbon: Weigh propylene compound monomers and dissolve them in water to obtain a pretreatment solution; after washing and drying, disperse the activated carbon in water, add the pretreatment solution and crosslinking agent, stir and react at 40-50℃ for 20-30 min, then add an initiator, raise the temperature to 60-70℃, and continue stirring and reacting for 2-3 h to obtain pretreated activated carbon.

[0040] Modified activated carbon: Long-chain alkylsilanes are added to water, acetic acid is added, and the mixture is stirred for 2-3 hours to obtain a pre-reaction solution; the pretreated activated carbon is dispersed in an alcohol solvent, the pre-reaction solution is added, the temperature is raised to 70-90℃, and the mixture is stirred for 4-6 hours. Finally, the modified activated carbon is obtained by washing and drying.

[0041] Preferably, the crosslinking agent includes one or more combinations of N,N-methylenebisacrylamide, N-hydroxymethylacrylamide, and trimethylolpropane triacrylate; the amount of crosslinking agent added is 15-20% of the mass of the propylene compound monomer.

[0042] Preferably, the initiator includes one or more combinations of potassium persulfate, ammonium persulfate, azobisisobutyronitrile, and benzoyl peroxide; the amount of initiator added is 10-15% of the mass of the propylene compound monomer.

[0043] Preferably, the mass ratio of long-chain alkylsilane, water and acetic acid in the pre-reaction solution is 1:(0.3-0.35):(3-4).

[0044] Preferably, the alcohol solvent includes any one of ethanol, methanol, and ethylene glycol.

[0045] By adopting the above technical solution, carboxyl and amide groups are first introduced onto the surface of activated carbon through copolymerization of propylene compounds, and then long-chain alkyl groups are introduced onto the surface of activated carbon through long-chain alkylsilanes. The resulting modified activated carbon can retain metal ions and residual organic matter, and can efficiently remove non-polar residues and metal ions from wastewater, as well as other colloidal impurities in wastewater, reducing the adverse effects of residual impurities on subsequent treatment steps.

[0046] Beneficial effects of this invention:

[0047] 1. This invention feeds pH-adjusted wastewater into a stripping tower, where free ammonia is transferred from the liquid phase to the gas phase via liquid-gas mass transfer, effectively removing free ammonia. Atomized deodorizing liquid is also introduced into the stripping tower, maximizing the contact area between the deodorizing liquid and the wastewater. The deodorizing liquid neutralizes and decomposes odorous substances in the wastewater, which are then expelled with the air. Simultaneously, an activated carbon packing layer is installed at the bottom of the stripping tower to adsorb impurities in the wastewater, reducing the load on subsequent treatment processes.

[0048] 2. In the deodorizing liquid of the present invention, the active decomposition of odor molecules by wild grass extract is utilized, and multi-ionic liquid and oxidant are added. The various metal ions in the multi-ionic liquid can work synergistically with the oxidant. On the one hand, it can capture odor molecules and accelerate the decomposition of odor substances; on the other hand, it can help improve the removal efficiency of free ammonia in wastewater, thereby effectively removing ammonia nitrogen pollutants in wastewater.

[0049] 3. The activated carbon filling layer set in this invention is composed of modified activated carbon, which can utilize the carboxyl and amide groups on the surface and the grafted long-chain alkyl groups to intercept the active substances and metal ion residues in the deodorizing liquid in the wastewater, thereby reducing the adverse effects of the deodorizing liquid residue on the subsequent biochemical treatment and flocculation treatment process, and improving the efficiency and effect of wastewater treatment. Detailed Implementation

[0050] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0051] Preparation Example 1

[0052] Preparation Example 1-1: A deodorizing liquid was prepared according to the following method:

[0053] Calcium carbonate, magnesium carbonate, and potassium hydroxide are added to water in sequence. The mixture is stirred at 40°C for 6 hours and then allowed to stand for 2 days. The supernatant is then collected and diluted 4 times with water to obtain a multi-ion liquid. The concentration of metal ions in the multi-ion liquid is 500 mmol / L, and the mass ratio of calcium ions, magnesium ions, and potassium ions is 3:1:1.

[0054] Take 450g of multi-ion liquid, and add 50g of wild grass extract (the wild grass extract is a mixed solution of wild chrysanthemum extract and wild licorice extract in a mass ratio of 1:1), 30g of hydrogen peroxide and 60g of sodium bicarbonate in sequence. After stirring and mixing, this is the deodorant stock solution.

[0055] Dilute the deodorant concentrate with water 25 times to obtain the deodorizing solution.

[0056] Preparation Examples 1-2 and 1-3 are deodorizing liquids, differing from Preparation Example 1-1 only in that the raw material ratio of the deodorizing agent stock solution is adjusted, as shown in Table 1:

[0057] Table 1. Raw material ratios of deodorant stock solutions in Preparation Examples 1-1 to 1-3

[0058] Preparation Example 1-1 Preparation Examples 1-2 Preparation Examples 1-3 Multi-ionic liquid / g 450 400 500 Wild grass extract / g 50 60 30 hydrogen peroxide / g 30 20 40 Sodium bicarbonate / g 60 50 80

[0059] Preparation Examples 1-4, a deodorizing liquid, differs from Preparation Example 1-1 only in that the multi-ionic liquid is prepared by the following method:

[0060] Calcium carbonate and magnesium carbonate are added to water in sequence, and the mixture is stirred at 40°C for 6 hours. After standing for 2 days, the supernatant is collected. The supernatant is diluted with water by 4 times to obtain a multi-ion liquid. The concentration of metal ions in the multi-ion liquid is 500 mmol / L, and the mass ratio of calcium ions to magnesium ions is 3:1.

[0061] Preparation Examples 1-5, a deodorizing liquid, differs from Preparation Example 1-1 only in that the multi-ionic liquid is prepared according to the following method:

[0062] Calcium carbonate, magnesium carbonate, potassium hydroxide, and zinc sulfate are added to water in sequence. The mixture is stirred at 40°C for 6 hours and then allowed to stand for 2 days. The supernatant is then collected and diluted 4 times with water to obtain a multi-ion liquid. The concentration of metal ions in the multi-ion liquid is 500 mmol / L, and the mass ratio of calcium ions, magnesium ions, potassium ions, and zinc ions is 3:1:1:1.

[0063] Preparation Examples 1-6, a deodorizing liquid, differs from Preparation Example 1-1 only in that wild herb extract is not added.

[0064] Preparation Examples 1-7, a deodorizing liquid, differs from Preparation Example 1-1 only in that hydrogen peroxide is not added.

[0065] Preparation Examples 1-8, a deodorizing liquid, differs from Preparation Example 1-1 only in that no multi-ionic liquid is added.

[0066] Preparation Example 2

[0067] Preparation Example 2-1: A modified activated carbon was prepared according to the following method:

[0068] Pretreatment of activated carbon: 0.6g of propylene monomer was dissolved in 20mL of water to obtain a pretreatment solution, wherein the propylene monomer included methacrylamide and acrylic acid in a mass ratio of 1:3; 10g of activated carbon was washed and dried and dispersed in 250mL of water, the pretreatment solution and 0.1g of N,N-methylenebisacrylamide were added, and the mixture was stirred at 45℃ for 30min. Then 0.06g of potassium persulfate was added, the temperature was raised to 70℃, and the mixture was stirred for 2h to obtain pretreated activated carbon.

[0069] Modified activated carbon: 0.2 g of octadecyltrimethoxysilane was added to 0.6 g of water, and 0.06 g of acetic acid was added. The mixture was stirred for 2 h to obtain a pre-reaction solution. The pretreated activated carbon obtained above was dispersed in 250 mL of ethanol, and the pre-reaction solution was added. The temperature was raised to 80 °C and the mixture was stirred for 5 h. Finally, the modified activated carbon was obtained by washing and drying.

[0070] Preparation Example 2-2, a modified activated carbon, differs from Preparation Example 2-1 only in that the amount of propylene compound monomer added is 0.5g, wherein the propylene compound monomer includes methacrylamide and acrylic acid in a mass ratio of 1:2; and the amount of octadecyltrimethoxysilane added is 0.1g.

[0071] Preparation Example 2-3, a modified activated carbon, differs from Preparation Example 2-1 only in that the amount of propylene compound monomer added is 0.7g, wherein the propylene compound monomer includes methacrylamide and acrylic acid in a mass ratio of 1:4; and the amount of octadecyltrimethoxysilane added is 0.3g.

[0072] Preparation Example 2-4, a modified activated carbon, differs from Preparation Example 2-1 only in that an equal amount of acrylic acid is used to replace the propylene compound monomers of the mixture of methacrylamide and acrylic acid in a mass ratio of 1:3.

[0073] Preparation Example 2-5, a modified activated carbon, differs from Preparation Example 2-1 only in that an equal amount of methacrylamide is used to replace the propylene compound monomers of the mixture of methacrylamide and acrylic acid in a mass ratio of 1:3.

[0074] Preparation Examples 2-6: A modified activated carbon was prepared according to the following method:

[0075] Add 0.2g of octadecyltrimethoxysilane to 0.6g of water, add 0.06g of acetic acid, and stir for 2h to obtain a pre-reaction solution; after washing and drying, disperse 10g of activated carbon in 250mL of ethanol, add the pre-reaction solution, raise the temperature to 80℃, stir for 5h, and finally wash and dry to obtain modified activated carbon.

[0076] Preparation Examples 2-7: A modified activated carbon was prepared according to the following method:

[0077] 0.6 g of propylene monomer was dissolved in 20 mL of water to obtain a pretreatment solution, wherein the propylene monomer included methacrylamide and acrylic acid in a mass ratio of 1:3; 10 g of activated carbon was washed and dried and dispersed in 250 mL of water, the pretreatment solution and 0.1 g of N,N-methylenebisacrylamide were added, and the mixture was stirred at 45 °C for 30 min. Then 0.06 g of potassium persulfate was added, the temperature was raised to 70 °C, and the mixture was stirred for 2 h to obtain modified activated carbon.

[0078] Example

[0079] Example 1: A method for treating and deodorizing kitchen wastewater, comprising the following process steps:

[0080] S1. The kitchen wastewater is fed into the oil-water separation equipment for oil-water separation to remove the floating oil in the wastewater. Then, the separated wastewater is allowed to settle and the sludge generated by the sedimentation is removed.

[0081] S2. Add calcium hydroxide to the wastewater obtained after precipitation to adjust the pH value of the wastewater to 11;

[0082] S3. The adjusted wastewater is fed into the top of the stripping tower and falls into the bottom of the stripping tower through a spray device; there is an activated carbon filling layer at the bottom of the stripping tower, which is composed of the modified activated carbon prepared in Preparation Example 2-1, and is equipped with air outlets to blow air upwards. At the same time, the deodorizing liquid prepared in Preparation Example 1-1 is fed into the tower through a dosing system and a high-pressure atomization system, and the generated gas is discharged.

[0083] S4. Wastewater passing through the stripping tower enters the A / O biological treatment unit for biological treatment. The wastewater stays in the aerobic layer of the A / O biological treatment unit for 12 days and in the anoxic layer for 3 days. Then, sedimentation removes solid impurities and sludge from the wastewater.

[0084] S5. Finally, ferric chloride is added to the wastewater, and the coagulation reaction is carried out for 20 minutes to separate the solid and liquid. After disinfection, the wastewater is discharged in compliance with standards.

[0085] Example 2, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that an equal amount of the deodorizing liquid prepared in Preparation Example 1-2 is used to replace the deodorizing liquid prepared in Preparation Example 1-1.

[0086] Example 3, a method for deodorizing kitchen wastewater, differs from Example 1 only in that an equal amount of the deodorizing liquid prepared in Preparation Examples 1-3 is used to replace the deodorizing liquid prepared in Preparation Example 1-1.

[0087] Example 4, a method for deodorizing kitchen wastewater, differs from Example 1 only in that an equal amount of the deodorizing liquid prepared in Preparation Examples 1-4 is used to replace the deodorizing liquid prepared in Preparation Examples 1-1.

[0088] Example 5, a method for deodorizing kitchen wastewater, differs from Example 1 only in that an equal amount of the deodorizing liquid prepared in Examples 1-5 is used to replace the deodorizing liquid prepared in Example 1-1.

[0089] Example 6, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that the activated carbon filling layer is composed of the modified activated carbon prepared in Preparation Example 2-2.

[0090] Example 7, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that the activated carbon filling layer is composed of the modified activated carbon prepared in Examples 2-3.

[0091] Example 8, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that an equal amount of the deodorizing liquid prepared in Preparation Examples 1-6 is used to replace the deodorizing liquid prepared in Preparation Examples 1-1.

[0092] Example 9, a method for deodorizing kitchen wastewater, differs from Example 1 only in that an equal amount of the deodorizing liquid prepared in Preparation Examples 1-7 is used to replace the deodorizing liquid prepared in Preparation Examples 1-1.

[0093] Example 10, a method for deodorizing kitchen wastewater, differs from Example 1 only in that the deodorizing liquid prepared in Preparation Examples 1-1 is replaced with an equal amount of the deodorizing liquid prepared in Preparation Examples 1-8.

[0094] Example 11, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that the activated carbon filling layer is composed of the modified activated carbon prepared in Examples 2-4.

[0095] Example 12, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that the activated carbon filling layer is composed of the modified activated carbon prepared in Examples 2-5.

[0096] Example 13, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that the activated carbon filling layer is composed of the modified activated carbon prepared in Examples 2-6.

[0097] Example 14, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that the activated carbon filling layer is composed of the modified activated carbon prepared in Examples 2-7.

[0098] Comparative Example

[0099] Comparative Example 1, a kitchen wastewater treatment and deodorization scheme, differs from Example 1 only in that the activated carbon filling layer is composed of unmodified activated carbon.

[0100] Comparative Example 2, a kitchen wastewater treatment and deodorization scheme, differs from Example 1 only in that no activated carbon packing layer is set below the stripping tower.

[0101] Comparative Example 3 is a kitchen wastewater treatment and deodorization scheme, which differs from Example 1 only in that the deodorizing liquid prepared in Preparation Example 1-1 is not introduced into the stripping tower.

[0102] Comparative Example 4 is a kitchen wastewater treatment and deodorization scheme, which differs from Example 1 only in that no activated carbon packing layer is set below the stripping tower and the deodorizing liquid prepared in Preparation Example 1-1 is not introduced into the stripping tower.

[0103] Performance testing

[0104] Kitchen wastewater was collected, with an average COD of 14000 mg / L and an ammonia nitrogen content of 2000 mg / L. The wastewater was then tested using the deodorization methods described in the examples and comparative examples. The average COD and ammonia nitrogen content of the treated wastewater were measured, and the corresponding removal rates were calculated.

[0105] The results of the above experiments are shown in Table 2:

[0106] Table 2 Performance test results

[0107]

[0108] According to Table 2, and in conjunction with Examples 1 and 8-10, it can be seen that the removal rates of Examples 8-10 decreased. This is because the composition of the deodorizing liquid was adjusted in Examples 8-10. Example 8 did not add wild grass extract, resulting in a significant decrease in the decomposition efficiency of odor substances. These odor substances entered the subsequent treatment stage with the wastewater, but the removal efficiency was poor and it also affected the removal efficiency of organic pollutants. Example 9 did not add an oxidant, which reduced the generation of active oxygen during wastewater treatment, leading to a decrease in the removal rate of odor molecules and a decrease in the removal rate of free ammonia. Example 10 did not add a multi-ionic liquid, resulting in a decrease in the capture efficiency of odor substances and the conversion efficiency of free ammonia to the gas phase, thus affecting the overall pollutant removal efficiency.

[0109] Based on Examples 1, 11-14, and Comparative Example 1, it can be seen that the removal rates of Examples 11-14 and Comparative Example 1 decreased. This is because Examples 11-14 and Comparative Example 1 mainly involved adjusting the modified activated carbon. The lack of carboxyl or amide groups on the surface of the modified activated carbon reduces its adsorption and capture effect on metal ions. The lack of long-chain alkyl groups reduces the adsorption of non-polar deodorizing liquid residue molecules and small molecules. Without modification, a large amount of deodorizing liquid residue will enter the next stage of wastewater treatment with the wastewater, thus affecting the biochemical treatment activity and flocculation process, resulting in a decrease in the removal rate of ammonia nitrogen and other pollutants in the wastewater.

[0110] Based on Example 1 and Comparative Examples 2-4, it can be seen that the removal rate of Comparative Examples 2-4 is lower than that of Example 1. This is because, compared to Example 1, Comparative Examples 2-4 did not have a deodorizing liquid or activated carbon packing layer, or neither, in the stripping tower. This indicates that the neutralization and decomposition of odor molecules by the deodorizing liquid and its role in promoting the conversion of free ammonia into the gas phase can improve the overall treatment effect on wastewater pollutants. The adsorption of residual molecules from the deodorizing liquid and the adsorption of colloidal or macromolecular pollutants in the wastewater by the activated carbon packing layer can also improve the treatment efficiency of subsequent treatment steps, thereby improving the treatment effect on wastewater pollutants.

[0111] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A method for treating and deodorizing kitchen wastewater, characterized in that, The process includes the following steps: S1. The kitchen wastewater is fed into the oil-water separation equipment for oil-water separation, and then the wastewater obtained after separation is settled to remove the sludge generated by the sedimentation. S2. Add alkali to the wastewater obtained after sedimentation to adjust the pH value of the wastewater to 9-11; S3. The adjusted wastewater is fed into the top of the stripping tower and falls into the bottom of the stripping tower through the spray device; there is an activated carbon filling layer at the bottom of the stripping tower and air outlets are set to blow air upwards. At the same time, deodorizing liquid is fed into the tower through the dosing system and the high-pressure atomization system, and the generated gas is discharged. S4. The wastewater passing through the stripping tower enters the A / O biological treatment unit for biological treatment, and then the solid impurities in the wastewater are removed by sedimentation; S5. Finally, add flocculant to the wastewater, separate the solid and liquid, and discharge it after disinfection; The deodorizing liquid is obtained by diluting the deodorizing agent stock solution with water by 20 to 30 times; the deodorizing agent stock solution includes the following raw materials in parts by weight: 3 to 6 parts of wild grass extract, 40 to 50 parts of multi-ion liquid, 2 to 4 parts of hydrogen peroxide and 5 to 8 parts of sodium bicarbonate; The wild herb extract includes one or more of the following: wild chrysanthemum extract, wild licorice extract, wild peony extract, wild kudzu flower extract, wild sesame extract, and wild thyme extract. The multi-ion liquid contains metal ions with a concentration of 400–600 mmol / L; the metal ions include at least two or more of calcium ions, magnesium ions, zinc ions, and potassium ions. The raw material for the activated carbon filling layer includes modified activated carbon; the surface of the modified activated carbon contains carboxyl-amide groups; and long-chain alkyl groups are grafted onto the surface of the modified activated carbon. The modified activated carbon was prepared according to the following method: Pretreatment of activated carbon: Weigh propylene compound monomers and dissolve them in water to obtain a pretreatment solution; after washing and drying, disperse the activated carbon in water, add the pretreatment solution and crosslinking agent, stir and react at 40-50℃ for 20-30 min, then add an initiator, raise the temperature to 60-70℃, and continue stirring and reacting for 2-3 h to obtain pretreated activated carbon. Modified activated carbon: Add long-chain alkylsilane to water, add acetic acid, and stir for 2-3 hours to obtain a pre-reaction solution; Pretreated activated carbon was dispersed in an alcohol solvent, a pre-reaction solution was added, the temperature was raised to 70-90℃, and the reaction was stirred for 4-6 hours. Finally, the carbon was washed and dried to obtain modified activated carbon.

2. The method for treating and deodorizing kitchen wastewater according to claim 1, characterized in that, During the process of inputting the deodorizing liquid, the diameter of the atomized droplets of the deodorizing liquid is controlled to be ≤0.04mm.

3. The method for treating and deodorizing kitchen wastewater according to claim 1, characterized in that, The deodorant stock solution was prepared according to the following method: Preparation of multi-ionic liquids: Soluble metal ion compounds are added sequentially to water, and the mixture is stirred at 30-50°C for 4-8 hours. After standing for 1-2 days, the supernatant is collected and diluted with water 3-5 times to obtain the multi-ionic liquid. Preparation of deodorant stock solution: Wild grass extract, oxidant and additives are added sequentially to a multi-ionic liquid and stirred to obtain the deodorant stock solution.

4. The method for treating and deodorizing kitchen wastewater according to claim 1, characterized in that, The propylene compound monomers include acrylamide monomer and acrylic acid monomer in a mass ratio of 1:(2-4).

5. The method for treating and deodorizing kitchen wastewater according to claim 4, characterized in that, The acrylamide monomer includes one or more combinations of methacrylamide, acrylamide, N,N-dimethylacrylamide and N-hydroxymethylacrylamide; the acrylic monomer includes one or more combinations of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate and methyl methacrylate.

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