Kitchen wastewater treatment and deodorization method

Abstract

The invention discloses a deodorization method for kitchen wastewater treatment, and belongs to the field of wastewater treatment. The wastewater treatment method comprises the steps of oil-water separation, pH value adjustment, nitrogen removal and deodorization by an air stripping tower, activated carbon adsorption, biochemical treatment and flocculation treatment, in the nitrogen removal and deodorization links of the air stripping tower, adjusted wastewater is input from the upper part of the air stripping tower and falls into the lower part of the air stripping tower through a spraying device, air is blown upwards through an air opening in the lower part of the air stripping tower, and the wastewater is subjected to flocculation treatment. Free ammonia in waste water can be transferred from a liquid phase to a gas phase, atomized deodorization liquid is input into the device and makes contact with spraying waste water, the contact area between the deodorization liquid and the waste water is increased to the maximum extent, the deodorization liquid is accelerated to neutralize and decompose odor substances in the waste water, and the odor substances are discharged along with air after being decomposed. Finally, an activated carbon filling layer is arranged at the bottom end of the air stripping tower, impurities in the wastewater are adsorbed, residual deodorization liquid is intercepted, subsequent treatment loads and adverse effects are reduced, and the overall wastewater treatment and deodorization efficiency and effect are improved.

Description

Technical Field

[0001] The present invention relates to the field of wastewater treatment, and in particular to a method for treating and deodorizing kitchen wastewater. Background Art

[0002] Kitchen wastewater contains high concentrations of organic matter such as grease, protein, starch, suspended solids and putrefactive substances. Its COD value is extremely high, and the water quality fluctuates greatly. It is easy to ferment and produce foul-smelling gases. If untreated kitchen wastewater is directly discharged, it will cause environmental risks such as eutrophication of water bodies, sewer blockage and air pollution. The accompanying foul-smelling gases pose a dual threat to the surrounding environment and human health.

[0003] Physicochemical and biological treatment methods are commonly used to treat food wastewater. However, physical adsorption processes have insufficient removal rates for dissolved odorous substances, chemical oxidation processes have high costs, and biological treatment processes have long treatment cycles, resulting in reduced deodorization efficiency. Ineffective deodorization measures during food wastewater treatment can exacerbate air pollution, impacting the surrounding environment and people. Untreated odors, along with wastewater leakage or overflow, can also lead to eutrophication and dissolved oxygen depletion, threatening the survival of aquatic life.

[0004] Therefore, there is an urgent need to develop a food wastewater treatment method that can synergistically remove pollutants and odors, has strong impact resistance, and has low operation and maintenance costs to achieve effective wastewater treatment. Summary of the Invention

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

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

[0007] S1. The kitchen wastewater is fed into an oil-water separation device for oil-water separation, and the separated wastewater is then precipitated to remove the sludge generated by the precipitation;

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

[0009] S3. The regulated wastewater is input from 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 under the stripping tower, and a tuyere is provided to blow air upward, while the dosing system and high-pressure atomization system are used to input the deodorizing liquid inward and discharge the generated gas;

[0010] S4. The wastewater from the stripping tower enters the A / O biochemical treatment unit for biochemical treatment, and then precipitates to remove solid impurities in the wastewater;

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

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

[0013] Preferably, the base comprises sodium hydroxide, calcium oxide, or a combination of one or more of calcium hydroxide.

[0014] Preferably, the flocculant includes any one of iron salt, aluminum salt and high molecular weight flocculant.

[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, by adding alkali, the ammonia nitrogen in the wastewater can be converted from ammonium ions NH4 + The conversion into free ammonia can provide favorable conditions for subsequent wastewater treatment steps.

[0016] The regulated wastewater is then fed from the top of the stripping tower, and air is blown upward from below, forming countercurrent contact with the wastewater. The wastewater passes through a spraying device, where it is separated into smaller droplets, significantly increasing the contact area with the air. By utilizing the difference in ammonia concentration between the liquid and gas phases, free ammonia is transferred from the liquid phase to the gas phase, effectively removing the free ammonia in the wastewater. The stripping tower is also connected to a dosing system and a high-pressure atomization system, allowing the deodorant to enter the stripping tower in atomized form and contact the sprayed wastewater, greatly increasing the contact area with the wastewater and the odor molecules in the wastewater. The active ingredients in the deodorant can decompose hydrogen sulfide and other volatile organic compounds and odorous substances in the wastewater, neutralizing the odor or decomposing it into gas that is discharged with the air, thereby effectively removing the odor from the wastewater.

[0017] An activated carbon filling layer is installed beneath the stripping tower. The unique structural characteristics of activated carbon, namely its high specific surface area and developed microporous structure, do not hinder the discharge of wastewater while simultaneously adsorbing residual free ammonia and small molecular impurities remaining in the deodorizing liquid, thereby reducing the subsequent processing load. Through the synergistic effects of the stripping tower's air stripping, atomized deodorization, and the activated carbon filling layer, physical mass transfer, chemical reactions, and adsorption matrix are utilized to achieve efficient removal of free ammonia and odorous substances in the wastewater.

[0018] Finally, the wastewater is biochemically treated in an anaerobic / aerobic (A / O) biochemical treatment unit. The aerobic zone in the A / O biochemical treatment effectively degrades COD and BOD5 in the wastewater, and the anoxic zone effectively removes nitrogen and phosphorus from the wastewater. Finally, a flocculant is added for flocculation to remove colloidal pollutants and large, difficult-to-degrade pollutants. Pollutants in the wastewater are further adsorbed and removed. Finally, disinfection is performed, and the treated wastewater, meeting standards, is discharged. The treatment method of the present invention can effectively remove pollutants and odorous substances from food wastewater, improving pollutant removal efficiency.

[0019] Preferably, the deodorant liquid is obtained by diluting the deodorant stock solution with water 20 to 30 times; the deodorant stock solution comprises 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 additives.

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

[0021] Preferably, the polyionic liquid includes metal ions at a concentration of 400 to 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 oxidizing agent includes any one of potassium permanganate and hydrogen peroxide.

[0023] More preferably, the additive includes a combination of one or more of potassium hydroxide, sodium bicarbonate, sodium carbonate, boric acid, trideceth-8, sodium tripolyphosphate, sodium phosphate and ethanolamine.

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

[0025] Preparation of polyionic liquid: add soluble metal ion compounds to water in sequence, stir and react at 30-50°C for 4-8 hours, let it stand for 1-2 days, take the supernatant, and dilute the supernatant 3-5 times with water to obtain the polyionic liquid;

[0026] Preparation of deodorant stock solution: wild grass extract, oxidant and additive are added to the polyionic liquid in sequence, and the deodorant stock solution is obtained after stirring and mixing.

[0027] More preferably, the soluble metal ion compound includes a combination of two or more 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 a weed extract. As a natural plant extract, the weed extract can enhance the interaction between active substances and odor molecules in wastewater after atomization. The weed extract is rich in terpenes, tannins, alkaloids and sugars, and can decompose odorous substances through acid-base neutralization, oxidation-reduction and esterification reactions. In addition, the conjugated double bonds in the weed extract can provide a high-density electron cloud, which is conducive to attracting and capturing odor molecules in wastewater. Compared with other plant extracts, the weed extract has a strong deodorizing ability. In addition to being able to decompose odor molecules, it can also synergistically treat free ammonia in wastewater and increase the denitrification efficiency of wastewater.

[0029] At the same time, the deodorizing liquid of the present invention also includes a polyionic liquid, which includes a variety of metal ions. There is a rich synergistic effect between the multiple metal ions, which can quickly capture odorous substances dissipated in the air, react with odorous substances in wastewater, and prevent the diffusion of odorous gases. In addition, the deodorizing liquid is compounded with additives, most of which are alkaline substances, which can better react and decompose odorous substances in wastewater such as hydrogen sulfide and free ammonia.

[0030] The metal ions in the polyionic liquid can also act as catalysts to accelerate the dispersion of the oxidant. The active oxygen generated can, on the one hand, oxidize odor molecules and remove odorous substances in the wastewater; on the other hand, it can capture and adsorb free ammonia in the wastewater, converting the free ammonia into nitrogen and discharging it with the gas. In addition, the carbon dioxide generated when the active oxygen decomposes the organic matter in the wastewater will reduce the solubility of free ammonia in the wastewater, thereby further increasing the escape rate of free ammonia in the wastewater in the stripping tower, thereby effectively removing ammonia nitrogen pollutants in the wastewater.

[0031] Preferably, the raw material of 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 solution, the presence of free ammonia in the wastewater can be greatly reduced through the liquid-gas mass transfer effect of air and the deodorization treatment of the deodorizing liquid, and the odor substances in the wastewater can be greatly reduced, and the odor diffusion in the wastewater can be reduced. However, the active substance residues of the weed extract in the deodorizing liquid or the metal ion residues in the multi-ion liquid will affect the subsequent wastewater treatment steps. The active substance residues may introduce excessive organic carbon sources in the A / O biochemical treatment process, affecting the denitrification carbon-nitrogen balance, thereby causing a decrease in the total nitrogen removal rate, while the metal ion residues will affect the activity of nitrifying bacteria and denitrifying bacteria, interfere with microbial metabolism, thereby reducing the denitrification capacity of the system, and in the subsequent flocculation link, they will compete with the flocculant for the adsorption sites on the colloid surface in the wastewater, resulting in a decrease in sedimentation performance. An activated carbon filling layer is set at the bottom of the stripping tower to adsorb some impurity molecules in the wastewater, but the adsorption capacity of activated carbon is poor for non-polar deodorizing liquid residues and metal ions in the multi-ion liquid.

[0033] In order to solve the above problems, the raw material of the activated carbon filling layer of the present invention adopts modified activated carbon. The surface of the modified activated carbon contains carboxyl groups and amide groups, and is also grafted with long-chain alkyl groups. The long-chain alkyl groups enhance the affinity between the microporous structure of the activated carbon and the residual active small molecules in the deodorant liquid through hydrophobic interaction, thereby improving the adsorption capacity of the modified activated carbon for the deodorant liquid residue, and the amide groups can combine with some polar small molecules in the deodorant liquid through hydrogen bonding, thereby further improving the adsorption of the deodorant liquid residue.

[0034] The introduction of carboxyl and amide groups can cause ion exchange reactions or coordination reactions with various metal ions in the polyionic liquid, thereby improving the adsorption capacity of the modified activated carbon for residual metal ions. The residual metal ions are retained in the activated carbon filling layer and will not affect the subsequent treatment process. Moreover, the mesoporous ratio of the modified activated carbon is increased, which can increase the adsorption capacity for impurity molecules and improve the removal efficiency and effect of wastewater treatment.

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

[0036] Preferably, the acrylamide monomer includes a combination of one or more of methacrylamide, acrylamide, N,N-dimethylacrylamide and N-hydroxymethylacrylamide; the acrylic acid monomer includes a combination of one or more 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 monomer and dissolve it in water to obtain a pretreatment solution; after washing and drying the activated carbon, disperse it in water, add the pretreatment solution and cross-linking agent, stir and react at 40-50°C for 20-30 minutes, then add the initiator, increase the temperature to 60-70°C, and continue stirring and reacting for 2-3 hours to obtain pretreated activated carbon;

[0040] Modified activated carbon: add long-chain alkyl silane to water, add acetic acid, and stir for 2 to 3 hours to obtain a pre-reaction liquid; disperse the pretreated activated carbon in an alcohol solvent, add the pre-reaction liquid, increase the temperature to 70 to 90°C, stir and react for 4 to 6 hours, and finally wash and dry to obtain the modified activated carbon.

[0041] Preferably, the crosslinking agent includes a combination of one or more of N,N-methylenebisacrylamide, N-methylol acrylamide and trimethylolpropane triacrylate; the added amount of the crosslinking agent is 15-20% of the mass of the acrylic compound monomer.

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

[0043] Preferably, in the pre-reaction liquid, the mass ratio of long-chain alkylsilane, water and acetic acid 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 scheme, carboxyl groups and amide groups are first introduced on the surface of activated carbon through copolymerization of propylene compounds, and then long-chain alkyl groups are introduced on the surface of activated carbon through long-chain alkyl silane. The activated carbon filling composed of the modified activated carbon obtained can intercept metal ions and residual organic matter, and achieve efficient removal of non-polar residues and metal ions in wastewater, as well as other colloidal impurities in wastewater, thereby reducing the adverse effects of residual impurities on subsequent treatment steps.

[0046] Beneficial effects of the present invention:

[0047] 1. This invention introduces pH-adjusted wastewater into a stripping tower, where free ammonia in the wastewater is transferred from the liquid phase to the vapor phase through liquid-gas mass transfer, effectively removing it. Atomized deodorizing liquid is introduced into the stripping tower, where it comes into contact with the sprayed wastewater, maximizing the contact area between the deodorizing liquid and the wastewater. The deodorizing liquid neutralizes and decomposes odorous substances in the wastewater, removing them along with the air. An activated carbon layer is also installed at the bottom of the stripping tower to absorb impurities in the wastewater, reducing subsequent processing loads.

[0048] 2. The deodorizing liquid of the present invention utilizes the activity of weed extract to decompose odor molecules, and polyionic liquid and oxidant are added. The various metal ions in the polyionic liquid can cooperate with the oxidant to capture odor molecules and accelerate the decomposition of odorous substances. On the other hand, it can help improve the removal efficiency of free ammonia in wastewater, thereby effectively removing ammonia nitrogen pollutants in the wastewater.

[0049] 3. The activated carbon filling layer provided in the present 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 deodorizing liquid active substances and metal ion residues in the wastewater, thereby reducing the adverse effects of the deodorizing liquid residues on subsequent biochemical treatment and flocculation treatment processes, and improving the efficiency and effect of wastewater treatment. DETAILED DESCRIPTION

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

[0051] Preparation Example 1

[0052] Preparation Example 1-1, a deodorant liquid, was prepared according to the following method:

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

[0054] Take 450g of multi-ionic liquid, add 50g of wild grass extract (the wild grass extract is a mixed solution of wild chrysanthemum extract and wild licorice extract with a mass ratio of 1:1), 30g of hydrogen peroxide and 60g of sodium bicarbonate, and stir to mix to obtain the deodorant stock solution.

[0055] Dilute the deodorant stock solution with water 25 times to make the deodorant liquid.

[0056] Preparation Example 1-2 and Preparation Example 1-3 are deodorant liquids. The only difference from Preparation Example 1-1 is that the raw material ratio of the deodorant 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 Example 1-2 Preparation Example 1-3 Multi-ion liquid / g 450 400 500 Wild grass extract solution / g 50 60 30 Hydrogen peroxide / g 30 20 40 Sodium bicarbonate / g 60 50 80

[0059] Preparation Example 1-4, a deodorant liquid, differs from Preparation Example 1-1 only in that the polyionic liquid is prepared according to the following method:

[0060] Calcium carbonate and magnesium carbonate were added to water in sequence, stirred and reacted at 40°C for 6 hours, and then allowed to stand for 2 days. The supernatant was taken and diluted 4 times with water to obtain a multi-ionic liquid, wherein the concentration of metal ions in the multi-ionic liquid was 500 mmol / L, and the mass ratio of calcium ions to magnesium ions was 3:1.

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

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

[0063] Preparation Example 1-6 is a deodorant liquid, which differs from Preparation Example 1-1 only in that no wild grass extract is added.

[0064] Preparation Example 1-7 is a deodorizing liquid, which differs from Preparation Example 1-1 only in that no hydrogen peroxide is added.

[0065] Preparation Example 1-8 is a deodorant liquid, which differs from Preparation Example 1-1 only in that no polyionic liquid is added.

[0066] Preparation Example 2

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

[0068] Pre-treatment of activated carbon: 0.6 g of propylene compound monomer, including methacrylamide and acrylic acid with a mass ratio of 1:3, was dissolved in 20 mL of water to obtain a pre-treatment solution; 10 g of activated carbon was dispersed in 250 mL of water after being cleaned and dried, and the pre-treatment solution and 0.1 g of N,N-methylene bisacrylamide were added, and the reaction was stirred at 45°C for 30 min, and then 0.06 g of potassium persulfate was added, and the temperature was increased to 70°C, and the reaction was continuously stirred for 2 h to obtain pre-treated activated carbon;

[0069] Modified activated carbon: 0.2 g of octadecyl trimethoxysilane was added to 0.6 g of water, 0.06 g of acetic acid was added, and the mixture was stirred for 2 h to obtain a pre-reaction solution; the pre-treated activated carbon obtained above was dispersed in 250 mL of ethanol, the pre-reaction solution was added, the temperature was increased to 80°C, and the reaction was stirred for 5 h, and finally the modified activated carbon was obtained after being washed and dried.

[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 0.5 g, wherein the propylene compound monomer includes methacrylamide and acrylic acid with a mass ratio of 1:2; and the amount of octadecyl trimethoxysilane added is 0.1 g.

[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 0.7 g, wherein the propylene compound monomer includes methacrylamide and acrylic acid with a mass ratio of 1:4; and the amount of octadecyl trimethoxysilane added is 0.3 g.

[0072] Preparation Example 2-4, a modified activated carbon, differs from Preparation Example 2-1 only in that the propylene compound monomer after mixing methacrylamide and acrylic acid with a mass ratio of 1:3 is replaced by an equal amount of acrylic acid.

[0073] Preparation Example 2-5, a modified activated carbon, differs from Preparation Example 2-1 only in that the propylene compound monomer after mixing methacrylamide and acrylic acid with a mass ratio of 1:3 is replaced by an equal amount of methacrylamide.

[0074] Preparation Example 2-6, a modified activated carbon, is prepared according to the following method:

[0075] Preparation Example 2-6, a modified activated carbon, is prepared according to the following method:

[0076] Preparation Example 2-7, a modified activated carbon, is prepared according to the following method:

[0077] 0.6 g of propylene compound monomer was weighed and dissolved in 20 mL of water to obtain a pretreatment liquid, wherein the propylene compound monomer included methacrylamide and acrylic acid in a mass ratio of 1:3; 10 g of activated carbon was washed and dried and then dispersed in 250 mL of water, and the pretreatment liquid and 0.1 g of N,N-methylenebisacrylamide were added. The mixture was stirred and reacted at 45°C for 30 minutes, and then 0.06 g of potassium persulfate was added. The temperature was raised to 70°C and the stirring reaction was continued for 2 hours 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. Feed the kitchen wastewater into the oil-water separation equipment for oil-water separation to remove floating oil in the wastewater. The separated wastewater is then precipitated and the sludge generated by the precipitation is removed.

[0081] S2. Calcium hydroxide was added to the wastewater obtained after precipitation to adjust the pH value of the wastewater to 11;

[0082] S3. The regulated wastewater is input from the top of the stripping tower and falls into the bottom of the stripping tower through a spray device; an activated carbon filling layer is provided below the stripping tower, wherein the activated carbon filling layer is composed of the modified activated carbon prepared in Preparation Example 2-1, and an air outlet is provided to blow air upward, while the deodorizing liquid prepared in Preparation Example 1-1 is input into the inside through the dosing system and the high-pressure atomization system, and the generated gas is discharged;

[0083] S4. The wastewater from the stripping tower enters the A / O biochemical treatment unit for biochemical treatment, where the wastewater stays in the aerobic layer of the A / O biochemical treatment unit for 12 days and in the anoxic layer for 3 days, and then solid impurities and sludge are removed from the wastewater by precipitation;

[0084] S5. Finally, add ferric chloride into the wastewater, coagulate for 20 minutes, separate the solid and liquid, and then discharge it in compliance with the standards after disinfection.

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

[0086] Example 3, a method for treating and deodorizing kitchen wastewater, is different from Example 1 only in that the deodorizing liquid prepared in Preparation Example 1-1 is replaced by an equal amount of the deodorizing liquid prepared in Preparation Example 1-3.

[0087] Example 4 is a method for treating and deodorizing food wastewater. The only difference from Example 1 is that the deodorizing liquid prepared in Preparation Example 1-1 is replaced by an equal amount of the deodorizing liquid prepared in Preparation Example 1-4.

[0088] Example 5 is a method for treating and deodorizing food wastewater. The only difference from Example 1 is that the deodorizing liquid prepared in Preparation Example 1-1 is replaced by an equal amount of the deodorizing liquid prepared in Preparation Example 1-5.

[0089] Example 6, a method for treating and deodorizing food wastewater, is different 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 food wastewater, is different from Example 1 only in that the activated carbon filling layer is composed of the modified activated carbon prepared in Preparation Example 2-3.

[0091] Example 8, a method for treating and deodorizing food wastewater, is different from Example 1 only in that the deodorizing liquid prepared in Preparation Example 1-1 is replaced by an equal amount of the deodorizing liquid prepared in Preparation Example 1-6.

[0092] Example 9, a method for treating and deodorizing kitchen wastewater, differs from Example 1 only in that the deodorizing liquid prepared in Preparation Example 1-1 is replaced by an equal amount of the deodorizing liquid prepared in Preparation Example 1-7.

[0093] Example 10 is a method for treating and deodorizing food wastewater. The only difference from Example 1 is that the deodorizing liquid prepared in Preparation Example 1-1 is replaced by an equal amount of the deodorizing liquid prepared in Preparation Example 1-8.

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

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

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

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

[0098] Comparative Example

[0099] Comparative Example 1 is a solution for treating and deodorizing kitchen wastewater. The only difference from Example 1 is that the activated carbon filling layer is composed of unmodified activated carbon.

[0100] Comparative Example 2 is a solution for treating and deodorizing kitchen wastewater. The only difference from Example 1 is that no activated carbon filling layer is provided below the stripping tower.

[0101] Comparative Example 3 is a solution for treating and deodorizing kitchen wastewater. The only difference from Example 1 is that the deodorizing liquid prepared in Preparation Example 1-1 is not fed into the stripping tower.

[0102] Comparative Example 4 is a solution for treating and deodorizing kitchen wastewater. The only difference from Example 1 is that no activated carbon filling layer is provided below the stripping tower and the deodorizing liquid prepared in Preparation Example 1-1 is not fed into the stripping tower.

[0103] Performance testing

[0104] Kitchen wastewater was collected, with an average COD value of 14,000 mg / L and an ammonia nitrogen content of 2,000 mg / L. The wastewater was tested using the kitchen wastewater treatment and deodorization methods described in the examples and comparative examples. The average COD value and ammonia nitrogen content in the treated wastewater were measured, and the corresponding removal rates were calculated.

[0105] The above test results are shown in Table 2:

[0106] Table 2 Performance test results

[0107]

[0108] According to Table 2, combined with Examples 1 and 8-10, it can be seen that the removal rates of Examples 8-10 decreased. This is because the deodorant composition was adjusted in Examples 8-10. In particular, Example 8 did not add weed extract, which greatly reduced the decomposition efficiency of odorous substances. Odorous substances entered the subsequent treatment stage with the wastewater, but the removal efficiency was poor and affected the removal efficiency of organic pollutants. In Example 9, no oxidant was added, which reduced the generation of active oxygen during the wastewater treatment process, resulting in a decrease in the removal rate of odorous molecules and a decrease in the removal rate of free ammonia. In Example 10, no polyionic liquid was added, which reduced the capture efficiency of odorous substances and the efficiency of converting free ammonia to the gas phase, thus affecting the overall pollutant removal efficiency.

[0109] In combination with Example 1, Examples 11 to 14 and Comparative Example 1, it can be seen that the removal rates of Examples 11 to 14 and Comparative Example 1 are reduced. The reason is that Examples 11 to 14 and Comparative Example 1 mainly adjust the modified activated carbon. The surface of the modified activated carbon lacks the effect of carboxyl or amide groups, which will reduce the adsorption and capture effect of the activated carbon on metal ions. The lack of long-chain alkyl groups will reduce the adsorption of the activated carbon on residual molecules and small molecules of non-polar deodorizing liquid. Without modification, a large amount of deodorizing liquid residue will enter the next stage of wastewater treatment with the wastewater, thereby 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] In combination with Example 1 and Comparative Examples 2 to 4, it can be seen that the removal rates of Comparative Examples 2 to 4 are lower than those of Example 1. The reason is that, compared with Example 1, no deodorizing liquid or activated carbon filling layer or both are set in the stripping tower of Comparative Examples 2 to 4, which shows that the neutralization and decomposition effect of the deodorizing liquid on odor molecules and the promotion of the conversion of free ammonia into gas phase can improve the overall treatment effect of wastewater pollutants; the adsorption of residual molecules of the deodorizing liquid and the adsorption of colloids or macromolecular pollutants in the wastewater by the activated carbon filling layer can also improve the treatment efficiency of subsequent treatment steps, thereby improving the treatment effect of wastewater pollutants.

[0111] The above disclosures are only a few specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A method for treating and deodorizing kitchen wastewater, characterized in that: The process steps include: S1. The kitchen wastewater is fed into an oil-water separation device for oil-water separation, and the separated wastewater is then precipitated to remove the sludge generated by the precipitation; S2. Add alkali to the wastewater obtained after precipitation to adjust the pH value of the wastewater to 9-11; S3. The regulated wastewater is input from 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 under the stripping tower, and a tuyere is provided to blow air upward, while the dosing system and high-pressure atomization system are used to input the deodorizing liquid inward and discharge the generated gas; S4. The wastewater from the stripping tower enters the A / O biochemical treatment unit for biochemical treatment, and then precipitates to remove solid impurities in the wastewater; S5. Finally, add flocculants into the wastewater to separate the solid and liquid, and then discharge it after disinfection.

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

3. The method for treating and deodorizing kitchen wastewater according to claim 1, wherein: The deodorant liquid is obtained by diluting the deodorant stock liquid by 20 to 30 times with water; the deodorant stock liquid comprises 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 oxidant and 5 to 8 parts of additive.

4. The method for treating and deodorizing kitchen wastewater according to claim 3, wherein: The wild grass extract comprises a combination of one or more of wild chrysanthemum extract, wild licorice extract, wild peony extract, kudzu flower extract, wild sesame extract and wild thyme extract.

5. The method for treating and deodorizing kitchen wastewater according to claim 3, wherein: The multi-ionic liquid includes metal ions with a concentration of 400 to 600 mmol / L; the metal ions include at least two or more of calcium ions, magnesium ions, zinc ions and potassium ions.

6. The method for treating and deodorizing kitchen wastewater according to claim 3, wherein: The deodorant stock solution is prepared according to the following method: Preparation of polyionic liquid: add soluble metal ion compounds to water in sequence, stir and react at 30-50°C for 4-8 hours, let it stand for 1-2 days, take the supernatant, and dilute the supernatant 3-5 times with water to obtain the polyionic liquid; Preparation of deodorant stock solution: wild grass extract, oxidant and additive are added to the polyionic liquid in sequence, and the deodorant stock solution is obtained after stirring and mixing.

7. The method for treating and deodorizing kitchen wastewater according to claim 1, wherein: The raw material of 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.

8. The method for treating and deodorizing kitchen wastewater according to claim 7, wherein: The raw materials of the modified activated carbon include activated carbon, propylene compound monomer and long-chain alkyl silane in a mass ratio of 10: (0.5-0.7): (0.1-0.3); the propylene compound monomer includes acrylamide monomer and acrylic acid monomer in a mass ratio of 1: (2-4).

9. The method for treating and deodorizing kitchen wastewater according to claim 8, characterized in that: The acrylamide monomer includes a combination of one or more of methacrylamide, acrylamide, N,N-dimethylacrylamide and N-hydroxymethylacrylamide; the acrylic acid monomer includes a combination of one or more of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate and methyl methacrylate.

10. The method for treating and deodorizing kitchen wastewater according to claim 8, characterized in that: The modified activated carbon is prepared according to the following method: Pretreatment of activated carbon: Weigh propylene compound monomer and dissolve it in water to obtain a pretreatment solution; after washing and drying the activated carbon, disperse it in water, add the pretreatment solution and cross-linking agent, stir and react at 40-50°C for 20-30 minutes, then add the initiator, increase the temperature to 60-70°C, and continue stirring and reacting for 2-3 hours 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; The pretreated activated carbon is dispersed in an alcohol solvent, a pre-reaction liquid is added, the temperature is raised to 70-90° C., the mixture is stirred and reacted for 4-6 hours, and finally the modified activated carbon is obtained by washing and drying.

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