Treatment process for synthetic cooling flavorant production wastewater

Abstract

The present invention provides a treatment process for the production wastewater of synthetic cooling flavorants. The principle is as follows: Trace salicylic acid in the production wastewater of 122-type functional gel resin is used as a biodegradable co-substrate to co-treat the production wastewater of cooling flavorants, greatly improving the removal rates of hydrolysis acidification and anaerobic biochemistry. After being treated by the hydrolysis acidification-anaerobic-aerobic-flocculation process, the synthetic wastewater can meet the requirements of the indirect discharge standard of the "Quality Standard for Wastewater Discharged into Urban Sewers" GBT / 31962-2015, achieving the purpose of treating waste with waste and comprehensive utilization of resources.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment for the synthesis of food additives - cooling agents. Specifically, it relates to a microbial treatment process for synthetic wastewater generated during the synthesis of cooling agents. Background Art

[0002] Cooling agents are a type of food additive that can give people a feeling of coolness and freshness, and have the effects of refreshing and waking up the mind. They are widely used in the food, daily necessities, cosmetics, fragrance and flavor, medicine, tobacco, clothing, and aquaculture industries. For the cooling agent N,2,3 - trimethyl - isopropyl butyramide (cooling agent), its production and synthesis use propionitrile and 2 - bromopropane to generate an intermediate 2,3 - dimethyl - 2 - isopropyl butyronitrile through an alkylation reaction. The cooling agent intermediate 2,3 - dimethyl - 2 - isopropyl butyronitrile undergoes an amidation reaction to finally obtain the product N,2,3, - trimethyl - 2 - isopropyl butyramide. A certain amount of wastewater is generated during the synthesis process. The main organic pollutants remaining in the wastewater are the intermediate 2,3 - dimethyl - 2 - isopropyl butyronitrile and the product N,2,3 - trimethyl - 2 - isopropyl butyramide that has not been fully recovered. The mixed wastewater has a high COD (chemical oxygen demand), which can reach 12000 - 16000 mg / L, and has strong microbial inhibition. Currently, conventional treatment processes have low anaerobic degradation efficiency and high operating costs, and cannot meet the discharge requirements of relevant wastewater. The existing technology for synthetic wastewater has a high chemical oxygen demand, which can reach 12000 - 16000 mg / L, and has strong microbial inhibition. Currently, conventional treatment processes have low anaerobic degradation efficiency and high operating costs, and cannot meet the discharge requirements of relevant wastewater. Therefore, a solution needs to be given. Summary of the Invention

[0003] The purpose of the present invention is to provide a treatment process for cooling agent production wastewater, solve the problem of treating the synthesis wastewater of the cooling agent N,2,3 - trimethyl - 2 - isopropyl butyramide, mix it with the production wastewater for producing type 122 functional gel resin, and use the salicylic acid in the wastewater as the substrate for the cooling agent synthesis wastewater to form anaerobic co - degradation, solve the problem that the synthesis wastewater of the cooling agent N,2,3 - trimethyl - 2 - isopropyl butyramide is difficult to biodegrade, achieve an increase in the anaerobic acidification removal rate, and achieve the purpose of treating waste with waste and comprehensive utilization of resources.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A treatment process for synthetic cooling agent production wastewater includes the following steps:

[0006] Step 1: Use salicylic acid, the main pollutant in the wastewater from the production of type 122 functional gel resin, as a co-substrate for anaerobic co-degradation in the synthesis wastewater of cooling flavorants to degrade the organic matter in the cooling flavorant production wastewater, achieve co-degradation, and reach the goal of using waste to control waste and comprehensive utilization of resources;

[0007] Step 2: The co-substrate salicylic acid comes from the wastewater from the production of type 122 functional gel resin, and the salicylic acid content is 6000 - 8000 mg / L;

[0008] Step 3: Mix the wastewater in Step 2 with the synthesis wastewater of cooling flavorants. Preferably, the volume ratio of type 122 functional synthesis is (0.2 - 0.5):1. Homogenize and equalize the mixed wastewater, and the adjusted mixed wastewater enters the anaerobic hydrolysis acidification system for anaerobic acidification treatment;

[0009] The main organic pollutants in the synthesis wastewater of cooling flavorants are propionitrile, 2-bromopropane, intermediate 2,3-dimethyl-2-isopropylbutyronitrile, and the product N,2,3-trimethyl-2-isopropylbutyramide that is not completely recovered. Its anaerobic acidification biological removal rate is only 10 - 20%, which is too low for the anaerobic acidification microbial system to maintain operation; while the wastewater from the production of type 122 functional gel resin contains a certain amount of easily biodegradable substance - salicylic acid as a substrate. Due to the addition of the co-substrate, it plays a crucial role in the anaerobic acidification degradation of difficult-to-biodegradable organic matter; salicylic acid, namely o-hydroxybenzoic acid, due to its unique molecular structure with a hydroxyl group adjacent to a carboxylic acid group, is prone to ring opening during anaerobic acidification due to the action of anaerobic microorganisms, forming an alcohol-acid molecular structure that is easily degraded by anaerobic acidification microorganisms. Therefore, it provides sufficient carbon source and energy for the growth and reproduction of microorganisms in the anaerobic acidification of cooling flavorants; salicylic acid is necessary as the primary energy source and carbon source for the growth and metabolism of anaerobic acidification microorganisms during anaerobic acidification degradation. Although hydrolytic acidification microorganisms can obtain energy from the biological reaction of difficult-to-degrade organic matter, it is not enough to maintain the biological reaction; hydrolytic acidification microorganisms must obtain carbon source and energy from other easily degradable organic matter and cooperate with other microorganisms to open the rings of difficult-to-degrade cyclic compounds and break the chains of long-chain organic compounds to improve their degradation rate; the presence of salicylic acid supplements carbon source and energy for relevant microorganisms, which is beneficial to the growth of the total amount of microorganisms; based on the above principles, after mixing the synthesis wastewater for producing cooling flavorants and the wastewater from the production of type 122 functional gel resin, the anaerobic biochemical removal rate is greatly improved, achieving the goal of using waste to control waste and comprehensive utilization of resources;

[0010] Step 4: The mixed wastewater from Step 3 enters the hydrolysis acidification-anaerobic system for hydrolysis acidification anaerobic biological treatment. After adding the synthetic wastewater of Type 122 functional gel resin, a co-metabolism system of salicylic acid-synthetic wastewater is formed. For the refractory organic matters, the removal rate of anaerobic acidification is greatly improved. Most of the toxic and harmful organic matters in the wastewater are removed in the anaerobic acidification process section, providing guarantee for the stable operation of the subsequent anoxic-aerobic process section;

[0011] Preferably, the retention time (HRT) of the hydrolysis acidification process section is set to 24 - 72 hours, and the volumetric loading of the anaerobic process section is set to 0.5 - 3.0 kg COD / m³.d;

[0012] Step 5: The wastewater from Step 4 enters the anoxic-aerobic biological treatment process section for anoxic-aerobic biological treatment. Its basic principle is based on the activated sludge method. Through the microbial activated sludge environment of the alternately arranged anoxic section (A) and aerobic section (O), biodegradation of organic matters and nitrogen and phosphorus removal are realized; among them, the O section is an aerobic environment. Under the aeration condition, the organic matters in the sewage are oxidized and decomposed by aerobic microorganisms into carbon dioxide and water to realize the mineralization of organic matters, and nitrifying bacteria oxidize ammonia nitrogen into nitrate. The A section is an anoxic environment. The mixed liquor from the aerobic section is refluxed to the anoxic section and under the action of an external carbon source, denitrification biological treatment is carried out to further remove nitrogen and realize the further purification of the wastewater. Preferably, the anoxic-aerobic microbial treatment is in 2 stages, and the retention time (HRT) is set to 4 - 5 days;

[0013] Step 6: The wastewater from Step 5 after anoxic-aerobic biological treatment enters the polyferric sulfate coagulation process section to further remove the colloidal substances that microorganisms cannot degrade and reduce the chemical oxygen demand (COD) of the wastewater; in the aqueous solution of polyferric sulfate, there are a large number of multinuclear ions and inorganic macromolecular substances. Its relative molecular weight is as high as 10 5 Daltons. The presence of sulfate radicals in polyferric sulfate makes it easier to form macromolecules, increases the density of its flocs, and improves the precipitation speed; various forms of ions in polyferric sulfate can strongly adsorb on the surface of colloidal particles and suspended substances, neutralize their charges, reduce their potential, and the colloidal substance particles change from mutual repulsion to mutual attraction and aggregation precipitation, further removing the organic matters in the wastewater.

[0014] Furthermore, preferably, polyferric sulfate flocculation precipitation is adopted, the pH value of the flocculation process is controlled at 4.5 - 6.0, and after the precipitation reaction is completed, sodium hydroxide is used to adjust the pH value of the effluent to 6.0 - 9.0 to achieve up-to-standard discharge.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] The present invention provides a treatment process for the production wastewater of synthetic cooling flavorants. The principle is to utilize trace salicylic acid in the production wastewater of 122-type functional gel resin as a biodegradable matrix to co-treat the production wastewater of cooling flavorants, thereby greatly improving the removal rates of hydrolysis acidification and anaerobic biochemistry. After being treated by the hydrolysis acidification-anaerobic-aerobic-flocculation process, the synthetic wastewater can meet the requirements of the indirect discharge standard of the "Quality Standard for Wastewater Discharged into Urban Sewers" GBT / 31962-2015, achieving the purpose of treating waste with waste and comprehensive utilization of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a process flow diagram of a synthetic wastewater of a cooling flavorant according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Cooling flavorants are a type of food additive, and their chemical composition is N,2,3-trimethyl-2-isopropylbutyramide. During their synthesis process, a certain amount of chemical synthesis wastewater is generated, which has the characteristics of high pollutant content and inhibition of microorganisms. The main pollutants in the synthetic wastewater are: propionitrile, 2-bromopropane, intermediate 2,3-dimethyl-2-isopropylbutyronitrile, and the product N,2,3-trimethyl-2-isopropylbutyramide that has not been completely extracted. 122-type functional gel resin is mainly used for the adsorption and separation of fine chemical products, and the main pollutant in its production wastewater is salicylic acid. It has been found that when the synthetic wastewater of cooling flavorants is treated by anaerobic microorganisms alone, the degradation rate of its chemical oxygen demand (COD) is only 10-20%, and the low removal rate makes it impossible for anaerobic microorganisms to maintain normal life activities, and conventional biological treatment cannot meet the treatment requirements of the synthetic wastewater of cooling flavorants. The main pollutant in the production wastewater of 122-type functional gel resin is salicylic acid, with a chemical oxygen demand (COD) value of 8000-10000 mg / L, which is easily biodegradable, and its anaerobic biochemical removal rate is 60-70%. It has been studied and found that when the production wastewater of 122-type functional gel resin is mixed and homogenized with the synthetic wastewater of cooling flavorants in a certain proportion, the anaerobic biochemical chemical oxygen demand (COD) degradation rate of the mixed wastewater rises to 60-70%, realizing anaerobic biodegradation.

[0020] For example: A fine chemical production enterprise produces synthetic wastewater of cooling flavorant N,2,3-trimethyl-2-isopropylbutyramide (referred to as cooling flavorant for short), and uses hydrolysis acidification as the pretreatment process. The removal rates are as follows in the table:

[0021] Table 1 Variation Table of COD before and after Anaerobic Acidification Treatment of Synthetic Wastewater of Cooling Flavor Agent

[0022]

[0023] Table 2 Variation Table of COD before and after Anaerobic Acidification Pretreatment of Production Wastewater of Adding Type 122 Functional Gel Resin

[0024]

[0025] A fine chemical enterprise synthesizes and produces cooling flavor agents, generating a certain amount of synthetic wastewater. The synthetic wastewater has a high organic matter content and certain biological inhibition, and the conventional biological treatment process cannot meet the requirements. It synthesizes and produces Type 122 functional gel resin, and the main pollutants in its production wastewater are salicylic acid and trace phenol, and its anaerobic acidification removal rate is high, and the subsequent biological treatment can more easily meet the relevant discharge requirements. It is found that the wastewater generated from the simultaneous production of cooling flavor agents and Type 122 functional gel resin is treated by mixing in a certain proportion. Due to the presence of easily degradable salicylic acid, co-degradation occurs in the mixture of the two wastewaters, and the anaerobic acidification chemical oxygen demand (COD) removal rate reaches 60 - 70%, providing a guarantee for the subsequent biological treatment. The hydrolysis - acidification - anoxic - aerobic - polyferric sulfate coagulation treatment process can meet the requirements of relevant discharge standards.

[0026] The following further details a treatment process for cooling flavor agent production wastewater of the present invention. Its process flow chart is as shown in Figure 1 and includes the following steps.

[0027] Step 1: Collect and store the synthetic wastewater for synthesizing cooling flavor agents in a wastewater storage tank;

[0028] Step 2: Collect the wastewater for producing Type 122 functional gel resin in a production wastewater storage tank;

[0029] Step 3: The chemical oxygen demand (COD) of the synthetic wastewater for synthesizing cooling flavor agents is 10000 - 17000 mg / L, the chemical oxygen demand (COD) of the wastewater for producing Type 122 functional gel resin is 6000 - 10000 mg / L, and the content of salicylic acid in the wastewater is 3000 - 6000 mg / L; the synthetic wastewater for synthesizing cooling flavor agents and the wastewater for producing Type 122 functional gel resin are mixed evenly in an adjustment tank at a ratio of 1:(0.2 - 0.5), and at the same time, the pH of the mixed wastewater is adjusted to 6.0 - 9.0;

[0030] Step 4: The evenly mixed wastewater enters a hydrolysis acidification tank for hydrolysis acidification. The residence time of hydrolysis acidification is controlled within 24 - 72 hours. Under the action of hydrolysis acidification microorganisms, the organic matter molecules in the wastewater are ring - opened and chain - broken for degradation, and its biochemical performance is improved;

[0031] Step 5: The effluent from hydrolysis acidification enters the UASB (Upflow Anaerobic Sludge Bed) anaerobic reactor for anaerobic biological treatment. The volumetric loading of the anaerobic biological reactor is controlled within the range of 0.5 - 3.0 kg COD / m³·d. The organic matter in the water and salicylic acid form a co-degradation system for anaerobic co-degradation.

[0032] Step 6: The effluent from the UASB anaerobic reactor enters the anoxic-aerobic microbial treatment process section. The organic matter in the wastewater undergoes nitrification-denitrification biological reactions under the action of anoxic-aerobic microorganisms, and the wastewater is further purified.

[0033] Step 7: The aerobic effluent enters the polyferric sulfate coagulation reaction process section for coagulation reaction to remove colloidal substances that are not biodegradable by organisms. The pH value of the polyferric sulfate coagulation precipitation reaction is controlled at 4.5 - 6.0. After complete precipitation, the supernatant is adjusted to a pH of 6.0 - 9.0 with sodium hydroxide to achieve up-to-standard discharge.

[0034] The following is a detailed description of the implementation process of the present invention in combination with specific embodiments:

[0035] Example 1:

[0036] Taking a fine chemical factory in Inner Mongolia as an example, the synthetic wastewater of the cooling flavorant in this example has a daily output of 200 m³ of synthetic wastewater of the cooling flavorant. The enterprise also produces 122-type functional gel resin, with a daily wastewater output of 40 m³. Various wastewaters were originally treated separately using one set of equipment. It was found that the main pollutant salicylic acid in the wastewater from the production of 122-type functional gel resin has an anaerobic microbial co-degradation effect on the synthetic wastewater of the cooling flavorant, greatly improving the anaerobic acidification removal rate of the synthetic wastewater of the cooling flavorant.

[0037] When the synthetic wastewater of the cooling flavorant is treated separately, the influent and effluent indexes and removal rate of anaerobic acidification are as follows in the table:

[0038] Table 3 Average values of chemical oxygen demand (COD) of wastewater before and after pretreatment

[0039]

[0040] When the wastewater from the production of 122-type functional gel resin is added, the influent and effluent indexes and removal rate during anaerobic acidification pretreatment are as shown in Table 4.

[0041] Table 4 Average values of chemical oxygen demand (COD) of wastewater before and after adding resin wastewater pretreatment

[0042]

[0043] The chemical oxygen demand (COD) of the synthetic wastewater of the cooling flavorant is 12,866 mg / L, and the wastewater volume is 200 m³. It is homogenously mixed with the production wastewater of the 122-type functional gel resin with a chemical oxygen demand (COD) of 6,982 mg / L and a volume of 40 m³ at a mixing ratio of 1:0.2. The pH is adjusted to 7.40 with acid and alkali. After mixing and adjustment, the chemical oxygen demand (COD) of the wastewater is 11,855 mg / L.

[0044] The wastewater after mixing and adjustment enters the hydrolysis acidification tank for hydrolysis acidification treatment. The organic matter in the wastewater undergoes a chemical reaction with the hydrolysis acidification microorganisms, and the organic matter in the wastewater is degraded by ring opening and chain breaking, and the biochemical oxygen demand of the wastewater is improved. The preferred residence time for hydrolysis acidification is 48 hours.

[0045] The effluent from hydrolysis acidification enters the UASB anaerobic bioreactor for anaerobic biological reaction. The anaerobic temperature is controlled at 35 - 38 °C. The volumetric loading of the UASB anaerobic bioreactor is 1.5 kg COD / m³·d, and the effluent index is shown in Table 5.

[0046] The anaerobic effluent enters the anoxic-aerobic (A / O) microbial treatment system. Under the action of anoxic-aerobic microorganisms, the organic matter in the wastewater undergoes nitrification-denitrification biological reactions, and the organic matter and ammonia nitrogen in the wastewater are removed. The residence time (HRT) of the anoxic-aerobic microbial treatment process section is 4.5 days.

[0047] The biochemical effluent enters the polyferric sulfate coagulation reaction process section, and through polyferric sulfate coagulation, the residual pollutants in the wastewater are further removed.

[0048] The pH value for the polyferric sulfate coagulation reaction is controlled at 4.5, and the pH of the coagulation sedimentation effluent is adjusted to 7.2 with sodium hydroxide for up-to-standard discharge. The treatment process of "hydrolysis acidification + anaerobic biological treatment + anoxic-aerobic biological treatment + polyferric sulfate coagulation" can meet the indirect discharge standard of the "Quality Standard for Wastewater Discharged into Urban Sewers" (GBT / 31962 - 2015).

[0049] The removal rate table of the chemical oxygen demand (COD) of each unit in Example 1 is shown in Table 5. The chemical oxygen demand (COD) of the raw water after homogenization treatment is 11,855 mg / L.

[0050] Table 5 Removal effect of chemical oxygen demand (COD) in each process unit

[0051]

[0052] Example 2

[0053] Taking a fine chemical factory in Inner Mongolia as an example, the cooling flavorant synthetic wastewater in this embodiment is as follows: Taking the enterprise's daily production of 200 m³ of cooling flavorant synthetic wastewater as an example, the enterprise also produces 122-type functional gel resin, with a daily wastewater production of 100 m³. Various wastewaters were originally treated separately using one set of equipment. It was found that in the wastewater from the production of 122-type functional gel resin, the main pollutant, salicylic acid, has a co-degradation effect on anaerobic microorganisms in the cooling flavorant synthetic wastewater, significantly improving the anaerobic acidification removal rate of the cooling flavorant synthetic wastewater.

[0054] When the cooling flavorant synthetic wastewater is treated separately, the influent and effluent indexes and removal rate of anaerobic acidification are as follows in the table:

[0055] Table 6 Average values of chemical oxygen demand (COD) of wastewater before and after pretreatment

[0056]

[0057] For the wastewater from the production of 122-type functional gel resin, the influent and effluent indexes and removal rate during anaerobic acidification pretreatment are as follows in the table:

[0058] Table 7 Average values of chemical oxygen demand (COD) of wastewater before and after pretreatment of the wastewater with resin added

[0059]

[0060] The chemical oxygen demand (COD) of the cooling flavorant synthetic wastewater is 13602 mg / L, with a wastewater volume of 200 m³, and the chemical oxygen demand (COD) of the wastewater from the production of 122-type functional gel resin is 6827 mg / L, with a water volume of 100 m³. They are homogenously mixed at a mixing ratio of 1:0.5, and the pH is adjusted to 7.0 using acid and base. The chemical oxygen demand (COD) of the mixed and adjusted wastewater is 11344 mg / L.

[0061] The mixed and adjusted wastewater enters the hydrolysis acidification tank for hydrolysis acidification treatment. The organic matter in the wastewater undergoes a biochemical reaction with hydrolysis acidification microorganisms, the organic matter in the wastewater is ring-opened and chain-broken for degradation, and the biochemical performance of the wastewater is improved. The preferred residence time of hydrolysis acid is 40 hours.

[0062] The effluent from hydrolysis acidification enters the UASB anaerobic bioreactor for anaerobic biological reaction. The anaerobic temperature is controlled at 35 - 38 °C, and the volume loading of the UASB anaerobic bioreactor is 1.0 kg COD / m³·d. The effluent indexes are shown in Table 8.

[0063] The anaerobic effluent enters the anoxic-aerobic (A / O) microorganism treatment system. The organic matter in the wastewater undergoes nitrification-denitrification biological reactions under the action of anoxic-aerobic microorganisms, and the organic matter and ammonia nitrogen in the wastewater are removed. The residence time of the anoxic-aerobic microorganism treatment process section is 4.0 days.

[0064] The biochemical effluent enters the polyferric sulfate coagulation reaction process section, and the residual pollutants in the wastewater are further removed through polyferric sulfate coagulation.

[0065] The pH value of the polyferric sulfate coagulation reaction is controlled at 5.5, and the pH of the coagulation precipitation effluent is adjusted to 6.5 with sodium hydroxide to meet the discharge standards. The treatment process of "hydrolysis acid + anaerobic biological reaction + anoxic-aerobic biological treatment + polyferric sulfate coagulation" can meet the indirect discharge standards of the "Water Quality Standard for Sewage Discharge into Urban Sewers" (GBT / 31962-2015).

[0066] Example 2 Removal rate of chemical oxygen demand (COD) of each unit The chemical oxygen demand (COD) of raw water after homogenization treatment is 11344 mg / L.

[0067] Table 8 Chemical oxygen demand (COD) removal effect of each process unit

[0068]

[0069] Example 3

[0070] The synthetic wastewater of cooling agent in this embodiment is taken as an example of a fine chemical factory in Inner Mongolia: the enterprise produces 200m³ of synthetic wastewater of cooling agent per day. The enterprise also produces 80m³ of wastewater per day of 122 type functional gel resin. Various wastewaters were originally treated separately using a set of equipment. Studies have found that salicylic acid, the main pollutant in the production wastewater of 122 type functional gel resin, has an anaerobic microbial co-degradation effect on the synthetic wastewater of cooling agent, which greatly improves the anaerobic acidification removal rate of the synthetic wastewater of cooling agent.

[0071] When the synthetic wastewater of cooling agent is treated separately, the inlet and outlet water indicators and removal rates of anaerobic acidification are as shown in the following table.

[0072] Table 9 Average chemical oxygen demand (COD) of wastewater before and after pretreatment

[0073]

[0074] The inlet and outlet water indicators and removal rates of 122 functional gel resin production wastewater during anaerobic acidification pretreatment are as follows

[0075] Table 10 Average chemical oxygen demand (COD) of wastewater before and after resin wastewater pretreatment

[0076]

[0077] The chemical oxygen demand (COD) of the cooling agent synthesis wastewater is 12028 mg / L, and the wastewater volume is 200 m³. It is homogenously mixed with the chemical oxygen demand (COD) of the 122-type functional gel resin production wastewater, which is 6072 mg / L and the water volume is 80 m³. The mixing ratio is 1:0.4. The pH is adjusted to 7.2 with acid and alkali. The chemical oxygen demand (COD) of the wastewater after mixing and adjustment is 10326 mg / L.

[0078] The wastewater after mixing and adjustment enters the hydrolysis acidification tank for hydrolysis acidification pretreatment. The organic matter in the wastewater undergoes biochemical reactions with hydrolysis acidification microorganisms, and the organic matter in the wastewater is degraded by ring opening and chain breaking, and the biochemical performance of the wastewater is improved. The preferred hydrolysis acidification residence time is 50 hours.

[0079] The effluent from hydrolysis acidification enters the UASB anaerobic bioreactor for anaerobic biochemical treatment. The anaerobic temperature is controlled at 35 - 38 °C. The volume load of the UASB anaerobic bioreactor is 2.0 kg COD / m³·d, and the effluent index is shown in Table 11.

[0080] The anaerobic effluent enters the anoxic-aerobic (A / O) microbial treatment system. Under the action of anoxic-aerobic microorganisms, the organic matter in the wastewater undergoes nitrification-denitrification biochemical reactions, and the organic matter and ammonia nitrogen in the wastewater are removed. The residence time of the anoxic-aerobic biological treatment process is 4.8 days.

[0081] The wastewater after biological treatment enters the polyferric sulfate coagulation reaction process section. Through the coagulation of polyferric sulfate, the residual pollutants in the wastewater are further removed.

[0082] The pH value for the polyferric sulfate coagulation reaction is controlled at 5.0. For the effluent from coagulation sedimentation, the pH value is adjusted to 8.0 with sodium hydroxide for up-to-standard discharge. The treatment process of "hydrolysis acidification + anaerobic biological reaction + anoxic-aerobic biological treatment + polyferric sulfate coagulation" can meet the indirect discharge requirements of the "Water Quality Standard for Wastewater Discharged into Municipal Sewers" (GBT / 31962 - 2015).

[0083] The removal rate of the chemical oxygen demand (COD) of each unit in Example 3. The chemical oxygen demand (COD) of the raw water after homogenization treatment is 10326 mg / L.

[0084] Table 11 Water Quality Indexes of Each Unit

[0085]

[0086] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A process for treating wastewater from the production of synthetic cooling agents, characterized in that: The steps include: Step 1: using salicylic acid, a main pollutant in the wastewater produced from the production of 122-type functional gel resin, as a substrate for anaerobic co-degradation of the wastewater produced from the cooling agent, to degrade organic matter in the wastewater produced from the cooling agent; Step 2: The co-degradation matrix salicylic acid comes from the wastewater produced by the production of 122 type functional gel resin, and the salicylic acid content is 6000-8000 mg / L; Step 3: Mix the wastewater from step 2 with the wastewater from the cooling agent production, and mix them according to a volume ratio of (0.2-0.5):

1. The mixed wastewater is homogenized and adjusted, and the adjusted mixed wastewater enters the anaerobic hydrolysis acidification system for anaerobic acidification treatment, and the pH of the mixed wastewater is adjusted to 6.0-9.0; Step 4: The mixed wastewater from step 3 enters the hydrolysis acidification anaerobic system for hydrolysis acidification anaerobic biological treatment. The retention time of the hydrolysis acidification process section is set to 24-72 hours, and the volume load of the anaerobic process section is set to 0.53.0 kg COD / m³.d; Step 5: The wastewater from step 4 enters the anoxic-aerobic biological treatment process section for anoxic-aerobic biological treatment. The anoxic-aerobic microbial treatment is set to 2 stages, and the retention time is set to 4-5 days; Step 6: The wastewater after anoxic-aerobic biological treatment enters the polyferric sulfate coagulation process section.

2. The process for treating wastewater from the production of synthetic cooling agents according to claim 1, characterized in that: The mixed wastewater enters the hydrolysis acidification unit, and the residence time of the hydrolysis acidification process is 24-72 hours.

3. The process for treating wastewater from the production of synthetic cooling agents according to claim 1, characterized in that: The hydrolysis and acidification effluent enters the anaerobic biochemical unit. The anaerobic biochemical process adopts UASB and IC anaerobic bioreactors. The volume load of UASB anaerobic bioreactor is controlled at 0.5-3.0kg COD / m 3 ·d.

4. A process for treating wastewater from the production of synthetic cooling agents according to claim 3, characterized in that: The anaerobic biochemical effluent is connected to the aerobic biochemical unit using an anoxic-aerobic microbial treatment system, and the hydraulic retention time of the anoxic-aerobic microbial treatment system is controlled at 4-5 days.

5. The process for treating wastewater from the production of synthetic cooling agents according to claim 1, characterized in that: The aerobic effluent is subjected to deep treatment, and the deep treatment process adopts polyferric sulfate coagulation, the coagulation reaction controls the pH value to 4.5-6.0, and the effluent of the coagulation precipitation is adjusted to pH 6.0-9.0 with sodium hydroxide before indirect discharge.

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