A high-carbon alcohol waste lye resource treatment method

Abstract

The application discloses a high-carbon alcohol waste lye resource treatment method, and belongs to the technical field of waste lye treatment. The method comprises the following steps: water quality homogenization of the waste lye; acidification treatment of the homogenized waste lye by adding waste acid liquid; separation of organic phase and water phase of the waste lye in a chromatograph; ultraviolet light catalytic oxidation treatment of the organic phase; and delivery of the treated organic phase to a sewage treatment system as an additional carbon source. The waste lye treated by the method has significantly enhanced biodegradability; meanwhile, a new type of carbon source is obtained, which can be used in the AO process of the sewage treatment system, and compared with traditional additional carbon sources such as acetic acid and sodium acetate, can more effectively promote the denitrification of microorganisms, has better effluent water quality, has stronger denitrification effect, reduces the cost of three agents of the sewage field, realizes the resource utilization of the waste lye, and has certain economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of waste alkali treatment technology, specifically relating to a method for the resource-based treatment of high-carbon alcohol waste alkali. Background Technology

[0002] Higher alcohols, also known as advanced fatty alcohols, refer to mixtures of monohydric alcohols containing six or more carbon atoms. They are commonly used in the synthesis of surfactants, plasticizers, and detergents, and are widely applied in petrochemicals, machinery and mining, construction and metallurgy, papermaking, and food industries. Octanol and 2-propylheptanol (2-PH) are among the more widely used higher alcohols. The waste alkaline liquid generated during current higher alcohol production has the following characteristics: strong alkalinity (pH around 13); high chemical oxygen demand (COD) of 40,000 mg / L-100,000 mg / L; numerous toxic and harmful substances with complex composition and high concentrations, primarily aldehydes and ketones, including pentaldehyde and decaenoal, which are biotoxic and have poor biodegradability. Direct discharge into wastewater treatment plants can affect the stable operation of biological treatment facilities, and separate pretreatment is difficult.

[0003] Currently, there are three main methods for treating waste alkaline solutions: air oxidation, neutralization, and incineration. Air oxidation has the advantage of high conversion efficiency, but its disadvantages include high requirements for equipment materials, large investment, high energy consumption, and relatively low removal rates for some organic matter and COD. Neutralization has the advantage of a simple process, but its disadvantage is that the neutralized waste alkaline solution has a high salt content, which has a significant impact on downstream wastewater treatment plants. Incineration has the advantages of simple operation, a short process, and the ability to meet emission standards, but its disadvantages include high energy consumption and large investment.

[0004] Patent CN1124230C first acidifies the waste alkaline solution from the butanol and octanol unit with inorganic acid, and then adds an organic extractant for extraction. However, this method only achieves a COD removal rate of 50%, indicating low efficiency. Patent CN104071940B first acidifies the waste alkaline solution with inorganic acid, then concentrates the acidified solution through pervaporation membrane evaporation. After oil-water separation, it is cooled and crystallized to recover the sodium salt of inorganic acid. The crystallization kettle liquid is returned to the acidification reaction tube for recycling. The evaporation condensate is subjected to adsorption treatment. Part of the adsorption effluent is returned to the condensation unit for preparing alkaline solution, and the remaining effluent is discharged to a wastewater treatment plant for biological treatment. Although this method achieves the resource recovery of organic matter in the waste alkaline solution, it involves large equipment investment, complex processing technology, high energy consumption, and the system still cannot completely treat the accumulated crystallization kettle liquid. Patent CN101277907A discloses a method for treating wastewater from an acetal reaction process. The method involves treating the wastewater, whose pH value has been adjusted to 0-6, through single-stage or multi-stage extraction. The wastewater is then stripped and condensed to extract wastewater with low organic impurity content. The organic liquid obtained from the condensate phase separation is used as the extractant for single-stage or multi-stage extraction. However, this method still increases operating costs due to stripping, and the quality of the stripped water and subsequent treatment are not clearly explained.

[0005] On the other hand, biological nitrification-denitrification processes are widely used in wastewater denitrification due to their low cost and high efficiency. The anoxic-aerobic activated sludge process (AO process) is a commonly used biological treatment method in wastewater treatment, also known as a pre-denitrification biological treatment system, which mainly consists of nitrification and denitrification processes. Denitrification refers to the process by which heterotrophic denitrifying bacteria use organic carbon sources as electron donors to reduce nitrite and nitrate nitrogen produced during nitrification into gaseous nitrogen in an anaerobic environment. Adding an external carbon source to wastewater with a low carbon-to-nitrogen ratio (BOD5 / TN<3) is necessary to ensure denitrification. However, in recent years, the procurement costs of bulk chemicals such as acetic acid, which are traditional carbon sources, have been increasing year by year, making the search for alternative new carbon sources an urgent priority. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide an economical, efficient, and simple method for the resource-based treatment of high-carbon alcohol waste alkali liquid, which significantly enhances the biodegradability of the treated waste alkali liquid. Simultaneously, a novel carbon source is obtained, which can be used in the AO process of wastewater treatment systems to promote microbial denitrification, resulting in high-quality effluent and strong nitrogen removal. On the one hand, it serves as a carbon source to ensure efficient nitrogen removal in the biological treatment device; on the other hand, it achieves the harmless and resource-based utilization of waste alkali liquid.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for the resource-based treatment of high-carbon alcohol waste alkaline solution is provided, characterized by comprising the following steps:

[0008] (1) Waste alkaline solution is homogenized for water quality;

[0009] (2) Add waste acid to the homogenized waste alkaline solution for acidification treatment;

[0010] (3) The acidified waste liquid is sent to a chromatography system for phase separation, the aqueous phase is sent to the wastewater treatment system, and the organic phase is sent to the ultraviolet treatment system for ultraviolet photocatalytic oxidation treatment.

[0011] (4) The organic phase after ultraviolet photocatalytic oxidation in step (3) is sent to the anoxic tank of the sewage treatment system as an external carbon source and mixed with other wastewater. The wastewater treated in the anoxic tank enters the aerobic tank for nitrification. Part of the nitrified effluent is returned to the anoxic tank, and the remaining effluent enters the sedimentation tank for sedimentation and separation. Part of the sludge is returned to the anoxic tank, and the supernatant is discharged as effluent.

[0012] In some embodiments, in step (1), the water quality homogenization time is 1h-10h.

[0013] In some embodiments, in step (2), the pH value of the waste liquid after acidification is 3-5, and the temperature of acidification is ≤65℃.

[0014] In some embodiments, in step (3), the operating pressure of the chromatography is atmospheric pressure and the operating temperature is 15℃-65℃.

[0015] In some embodiments, in step (3), the ultraviolet treatment system includes a power supply, an ultraviolet lamp and a reaction tube. A quartz sleeve is provided inside the reaction tube, the ultraviolet lamp is installed inside the quartz sleeve, and the area outside the quartz sleeve is a sewage area. Based on the influent, the effective volume of the reaction tube satisfies the hydraulic retention time of 50s-100s.

[0016] In some embodiments, in step (3), the operating conditions of the ultraviolet treatment system are: the ultraviolet reaction temperature is 55℃-60℃, and the ultraviolet wavelength is 170nm-300nm.

[0017] In some embodiments, in step (4), the BOD5 / TN value of other wastewater is less than 3.

[0018] In some embodiments, in step (4), the pH of the wastewater treatment system is 6-9 and the sludge age is 15-18 days.

[0019] In some embodiments, in step (4), the reflux ratio of the nitrified effluent is 3-5, and the reflux ratio of the sedimentation tank sludge is 0.3-0.5.

[0020] In some embodiments, in step (4), the hydraulic retention time of the anoxic pool is 0.5h-2h.

[0021] In some embodiments, in step (4), the hydraulic retention time of the aerobic tank is 4h-6h.

[0022] In some embodiments, in step (4), the hydraulic retention time of the sedimentation tank is 2h-4h.

[0023] In some embodiments, in step (4), the dissolved oxygen concentration in the anoxic pool is 0.1 mg / L-0.3 mg / L.

[0024] In some embodiments, in step (4), the dissolved oxygen concentration in the aerobic tank is 4 mg / L-6 mg / L.

[0025] In some embodiments, the method for resource recovery of high-carbon alcohol waste alkali liquid may further include the step of: sending a portion of the unhomogenized waste alkali liquid directly to the aerobic tank of the wastewater treatment system as an added alkalinity.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] (1) This invention treats waste with waste by mixing waste acid into waste alkali to achieve acid-base neutralization, which reduces the amount of acid and alkali used to neutralize two streams of wastewater in the wastewater treatment plant and saves operating costs. At the same time, it avoids the use of dilution water, allowing the organic matter in the waste acid to dissolve into the waste alkali. The effective separation of biochemical and non-biochemical components can be achieved by acidification alone, which provides conditions for ultraviolet photocatalytic oxidation, reduces energy consumption and subsequent treatment load, is suitable for large-scale treatment, achieves atom economy, saves water resources, and the slightly acidic conditions can effectively prevent scaling.

[0028] (2) No reagents were added during the waste alkaline solution water quality homogenization-acidification treatment-chromatographic separation-ultraviolet oxidation process of the present invention, which avoids secondary pollution and saves operating costs; the selection of the chromatography device reduces the downstream load and improves the efficiency of ultraviolet light, which has the effect of energy saving and consumption reduction; at the same time, the biodegradability of ultraviolet water is enhanced and it can be directly used in the AO process.

[0029] (3) The present invention can reserve a small portion of untreated waste alkaline liquid as an external alkalinity directly added to the AO process, which increases the alkalinity of the raw water, strengthens the nitrification effect, and can be turned on or off according to the effluent quality and operating conditions of the wastewater treatment system, increasing the operational flexibility of the process.

[0030] (4) This invention utilizes high-carbon alcohol waste alkali liquid to obtain a novel carbon source, which can be used in the AO process of wastewater treatment systems. Compared with traditional external carbon sources such as acetic acid and sodium acetate, the organic matter in high-carbon alcohol waste alkali liquid is more complex and has uneven molecular weight. For microorganisms, it is a more balanced nutrient source, which can more effectively promote the denitrification of microorganisms. The microbial colonies cultivated from it are relatively rich. For wastewater rich in high concentrations of recalcitrant organic matter, this carbon source is conducive to the continuous degradation of microorganisms through gradual utilization, resulting in more thorough wastewater treatment and stronger denitrification. In contrast, acetic acid and sodium acetate are single nutrient sources with poor sustainability. At the same time, this invention reduces the cost of the three agents in wastewater treatment plants and realizes the resource utilization of waste alkali liquid, which has certain economic benefits. Attached Figure Description

[0031] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0032] Figure 1 This is a process flow diagram of the resource utilization treatment method for high carbon alcohol waste alkali liquid according to an embodiment of the present invention.

[0033] The labels in the diagram are as follows: 1-Homogenizing tank, 2-pH adjustment tank, 3-Chromatography unit, 4-UV treatment system, 5-Anoxic tank, 6-Aerobic tank, 7-Sedimentation tank. Detailed Implementation

[0034] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions mentioned in the specification and claims are generally described and defined below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0035] In this invention, the gradation refers to the distribution of nutrients in the carbon source.

[0036] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0037] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0038] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0039] This invention provides a method for the resource-based treatment of high-carbon alcohol waste alkaline solution, characterized by comprising the following steps:

[0040] (1) Waste alkaline solution is homogenized for water quality;

[0041] (2) Add waste acid to the homogenized waste alkaline solution for acidification treatment;

[0042] (3) The acidified waste liquid is sent to a chromatography system for phase separation, the aqueous phase is sent to the wastewater treatment system, and the organic phase is sent to the ultraviolet treatment system for ultraviolet photocatalytic oxidation treatment.

[0043] (4) The organic phase after ultraviolet photocatalytic oxidation in step (3) is sent to the anoxic tank of the sewage treatment system as an external carbon source and mixed with other wastewater. The wastewater treated in the anoxic tank enters the aerobic tank for nitrification. Part of the nitrified effluent is returned to the anoxic tank, and the remaining effluent enters the sedimentation tank for sedimentation and separation. Part of the sludge is returned to the anoxic tank, and the supernatant is discharged as treated water.

[0044] According to the processing method of the present invention, in some embodiments, in step (1), the water homogenization time is 1h-10h. It is understood that the water homogenization time can be any specific value among 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, and 10h, or any value within the range of 1h-10h. Water homogenization is a mixing process aimed at addressing the uneven distribution of waste alkali discharge, balancing the changes in water quality and quantity of the waste alkali, and ensuring a uniform distribution of the waste alkali inflow. In this invention, the water homogenization can be carried out in a homogenizing tank. This invention does not impose any special limitations on the homogenizing tank; it can be any conventional homogenizing tank in the art.

[0045] According to the treatment method of the present invention, in some embodiments, in step (2), the pH value of the waste liquid after acidification is 3-5. It can be understood that the pH value of the waste liquid after acidification can be any specific value among 3, 4, and 5, or any value within the range of 3-5; the temperature of the acidification treatment does not exceed 65°C, and further, the temperature of the acidification treatment is 5°C-45°C. In this application, the acidification treatment can be carried out in a pH adjustment tank. The material of the pH adjustment tank includes, but is not limited to, polytetrafluoroethylene, polyethylene, and acid and alkali resistant lining. This application achieves pH control by controlling the amount of waste acid entering the tank. If the pH is too high, the equipment and pipelines are prone to scaling. Too high a pH will also hinder the metabolic rate of microorganisms, which is not conducive to their growth and leads to a significant reduction in the denitrification rate. If the pH is too low, it will cause acid corrosion of the equipment and pipelines, increase investment costs, and if the pH is too low, fungi will completely dominate in the biological tank, and the nitrification reaction will almost stop. This application controls the acidification treatment temperature to not exceed 65°C by introducing circulating water for cooling. Excessive temperature is not conducive to the operation of the downstream chromatography, making it difficult for the aqueous phase and organic phase to separate, thus affecting the separation effect.

[0046] According to the processing method of the present invention, in some embodiments, in step (3), the operating pressure of the chromatography is atmospheric pressure and the operating temperature is 15℃-65℃. It can be understood that the operating temperature can be any specific value among 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, and 65℃, or any value within the range of 15℃-65℃.

[0047] In this invention, the chromatography apparatus consists of two phases: a stationary phase and a mobile phase. The stationary phase is mostly a solid substance or a component fixed to a solid, and its function is to adsorb or react the compounds in the mixture to be separated according to the strength of their affinity with the stationary phase. This invention can use conventional stationary phases in the art, including but not limited to silica gel, dextran, and polyvinyl alcohol. The mobile phase refers to a solvent or solution, which comes into contact with the stationary phase and continuously moves downwards, thereby gradually carrying out the mixture adsorbed or reacted on the stationary phase and separating them according to the strength of their affinity with the mobile phase. This invention can use conventional mobile phases in the art, including but not limited to water, chloroform, and methanol. This application achieves the separation of biodegradable and non-biodegradable components in mixed waste liquid by controlling the operating temperature and pressure of the chromatography apparatus. If the temperature is too high, the solubility of the medium increases, the required separation zone increases, and the separation efficiency of the equipment decreases; if the temperature is too low, it wastes circulating cooling water, and the false indications of instruments such as liquid level caused by low temperature are not conducive to the stable operation of the chromatography apparatus. This application achieves rapid separation of organic and aqueous phases through the use of a chromatography system, reducing downstream load and improving the efficiency of ultraviolet light.

[0048] According to the processing method of the present invention, in some embodiments, in step (3), the ultraviolet treatment system includes a power supply, an ultraviolet lamp, and a reaction tube. A quartz sleeve is disposed inside the reaction tube, and the ultraviolet lamp is installed inside the quartz sleeve. The area outside the quartz sleeve is a wastewater area. Based on the influent volume, the effective volume of the reaction tube satisfies a hydraulic retention time of 50s-100s. It is understood that the hydraulic retention time can be any specific value among 50s, 60s, 70s, 80s, 90s, and 100s, or any value within the range of 50s-100s. In this application, the quartz sleeve is preferably made of quartz to isolate the ultraviolet lamp from the wastewater medium. The reaction tube is made of materials including, but not limited to, quartz, polytetrafluoroethylene, and polyethylene.

[0049] According to the processing method of the present invention, in some embodiments, in step (3), the operating conditions of the ultraviolet processing system are: the ultraviolet reaction temperature is 55℃-60℃. It can be understood that the ultraviolet reaction temperature can be any specific value among 55℃, 56℃, 57℃, 58℃, 59℃, and 60℃, or any value within the range of 55℃-60℃; the ultraviolet wavelength is 170nm-300nm. It can be understood that the ultraviolet wavelength can be any specific value among 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, and 300nm, or any value within the range of 170nm-300nm.

[0050] In this application, the method for controlling the ultraviolet reaction temperature includes, but is not limited to, adjusting the power of the ultraviolet lamp. Preferably, the power of the ultraviolet lamp is 500W / m. 3 -2000W / m 3 It is understood that the power can be 500W / m 3 600W / m 3 700W / m 3 800W / m 3 900W / m 3 1000W / m 3 1100W / m 3 1200W / m 3 1300W / m 3 1400W / m 3 1500W / m 3 1600W / m 3 1700W / m 3 1800W / m 3 1900W / m 3 2000W / m3 Any specific value in it or 500W / m 3 -2000W / m 3 Any value within the range.

[0051] This application, by controlling the ultraviolet reaction temperature and ultraviolet wavelength within the specified range, ensures that the organic matter in the waste liquid is in an oxidized and excited state after being irradiated by high-intensity ultraviolet light. In particular, most organic matter such as pentanol and pentanal is oxidized and degraded, some COD is reduced, and biodegradability is significantly enhanced. If the ultraviolet reaction temperature is too low, the reaction will be incomplete; if the ultraviolet reaction temperature is too high, energy consumption will increase and the life of the ultraviolet lamp will be shortened. If the ultraviolet wavelength is below 170nm, the ultraviolet light penetration ability is weakened, and the central area of ​​the pipeline becomes a reaction dead zone. If the ultraviolet wavelength is above 300nm, the ultraviolet light energy is reduced, and the chain breaking purpose for recalcitrant organic matter cannot be achieved, thus limiting the ability to improve biodegradability.

[0052] According to the treatment method of the present invention, in some embodiments, in step (4), other wastewater refers to wastewater with a BOD5 / TN value of less than 3, requiring the addition of an external carbon source. BOD5 (Biochemical Oxygen Demand) is an important indicator that indirectly represents the degree of organic pollution in water by the amount of dissolved oxygen consumed by microbial metabolism. Generally, 5 days is used as the standard time for measuring BOD, hence it is called five-day biochemical oxygen demand, expressed as BOD5. TN is the total amount of various forms of inorganic and organic nitrogen in water, i.e., total nitrogen content. The BOD5 / TN (i.e., C / N) ratio is the main indicator for determining whether biological denitrification can be used. When BOD5 / TN is less than 3, denitrification cannot proceed without the addition of an external carbon source.

[0053] In this invention, the organic phase after ultraviolet photocatalytic oxidation treatment is used as an external carbon source and sent to the anoxic tank of the wastewater treatment system. This invention can use conventional external carbon source dosages in the art, for example, for a treatment scale Q=10000m³. 3 The total nitrogen in the influent is 100 mg / L. To achieve the discharge standard, the carbon source dosage can be 3000 kg COD / d.

[0054] Furthermore, in some specific embodiments, in step (4), the organic phase after ultraviolet photocatalytic oxidation treatment is sent to the anoxic tank of the sewage treatment system as an external carbon source and mixed with other wastewater introduced at a volume ratio of 1:150-1:350.

[0055] According to the treatment method of the present invention, in some embodiments, in step (4), the pH of the sewage treatment system is 6-9. It is understood that the pH can be any specific value among 6, 7, 8, and 9 or any value within the range of 6-9; the sludge age of the sewage treatment system is 15-18 days. It is understood that the sludge age can be any specific value among 15, 16, 17, and 18 or any value within the range of 15-18.

[0056] In this invention, the organic phase after ultraviolet photocatalytic oxidation treatment is sent as an external carbon source to the anoxic tank of the wastewater treatment system and mixed with other wastewater to form mixed influent. The BOD5 / COD ratio of the mixed influent needs to be greater than or equal to 0.3. The BOD5 / COD ratio can be used to determine the biodegradability of the influent; a value lower than this indicates extremely poor biodegradability, making biological treatment impossible.

[0057] According to the processing method of the present invention, in some embodiments, in step (4), the reflux ratio of the nitrified effluent is 3-5. It can be understood that the reflux ratio of the nitrified effluent can be any specific value among 3, 4, and 5, or any value within the range of 3-5; the reflux ratio of the sedimentation tank sludge is 0.3-0.5. It can be understood that the reflux ratio of the sludge can be any specific value among 0.3, 0.4, and 0.5, or any value within the range of 0.3-0.5.

[0058] According to the processing method of the present invention, in some embodiments, in step (4), the hydraulic retention time of the anoxic tank is 0.5h-2h. It is understood that the hydraulic retention time of the anoxic tank can be any specific value among 0.5h, 1h, 1.5h, and 2h, or any value within the range of 0.5h-2h; the hydraulic retention time of the aerobic tank is 4h-6h. It is understood that the hydraulic retention time of the aerobic tank can be any specific value among 4h, 4.5h, 5h, 5.5h, and 6h, or any value within the range of 4h-6h; the hydraulic retention time of the sedimentation tank is 2h-4h. It is understood that the hydraulic retention time of the sedimentation tank can be any specific value among 2h, 2.5h, 3h, 3.5h, and 4h, or any value within the range of 2h-4h. The present invention, by controlling the hydraulic retention times of the anoxic tank, aerobic tank, and sedimentation tank respectively, can better control the degree of denitrification, nitrification, and sedimentation separation, thereby ensuring better nitrogen and carbon removal effects.

[0059] According to the processing method of the present invention, in some embodiments, in step (4), the dissolved oxygen concentration in the anoxic tank is 0.1 mg / L-0.3 mg / L. It is understood that the dissolved oxygen concentration in the anoxic tank can be any specific value among 0.1 mg / L, 0.15 mg / L, 0.2 mg / L, 0.25 mg / L, and 0.3 mg / L, or any value within the range of 0.1 mg / L-0.3 mg / L; the dissolved oxygen concentration in the aerobic tank is 4 mg / L-6 mg / L. It is understood that the dissolved oxygen concentration in the aerobic tank can be any specific value among 4 mg / L, 4.5 mg / L, 5 mg / L, 5.5 mg / L, and 6 mg / L, or any value within the range of 4 mg / L-6 mg / L. This application controls the dissolved oxygen concentration in the anoxic and aerobic tanks, thereby screening out corresponding anoxic bacteria (such as heterotrophic denitrifying bacteria) or aerobic bacteria (such as nitrifying bacteria) and inhibiting the reproduction of other bacteria. By utilizing their life activities, it can specifically remove certain pollutants in the water, thereby achieving efficient water purification.

[0060] In this invention, in the anoxic tank, microorganisms such as heterotrophic denitrifying bacteria can oxidize most of the organic matter in the wastewater with ammonia, releasing ammonia nitrogen; in the aerobic tank, microorganisms such as aerobic nitrifying bacteria can oxidize ammonia nitrogen into nitrate nitrogen, which is then returned to the anoxic tank through reflux control. Under anoxic conditions, the denitrification of heterotrophic denitrifying bacteria reduces nitrate nitrogen to molecular nitrogen, completing the cycle of C, N, and O in the ecosystem and achieving denitrification treatment of wastewater.

[0061] According to the treatment method of the present invention, in some embodiments, the resource recovery treatment method for high-carbon alcohol waste alkaline liquid optionally further includes the step of: directly sending a small portion of the untreated waste alkaline liquid to the aerobic tank of the sewage treatment system as external alkalinity. Further, the volume ratio of the untreated waste alkaline liquid to the total influent volume of the sewage treatment system is ≤1 / 300. In this invention, this step can be selected for use at any time based on the operating conditions and the effluent quality of the sewage treatment process; when alkalinity is insufficient, this step can be used to enhance nitrification; when alkalinity is sufficient, this step can be stopped to further optimize the carbon source dosage.

[0062] This invention provides a novel carbon source through special treatment of high-carbon alcohol waste alkaline solution. This carbon source can be added to wastewater treatment systems. Compared to traditional external carbon sources such as acetic acid and sodium acetate, the organic phase obtained after this special treatment has a more complex composition and uneven molecular weight. For microorganisms, this provides a more balanced nutrient profile, effectively promoting denitrification. The resulting microbial colonies are more abundant. For wastewater rich in high concentrations of recalcitrant organic matter, this carbon source facilitates continuous degradation by microorganisms through gradual utilization, resulting in more thorough wastewater treatment, better effluent quality, and stronger denitrification. In contrast, acetic acid and sodium acetate are single nutrient sources with poor sustainability. Furthermore, this invention reduces the cost of the three treatment agents (acetic acid, sodium acetate, and acetic acid) in wastewater treatment plants and achieves resource utilization of waste alkaline solution, thus offering certain economic benefits.

[0063] The present invention will be described in detail below through embodiments. It should be understood that the following embodiments are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0064] In this invention, the testing methods for each performance parameter in the embodiments and comparative examples are as follows:

[0065] Chemical oxygen demand (COD): Tested according to HJ828-2017 standard;

[0066] Five-day biochemical oxygen demand (BOD5): tested according to HJ505-2009 standard;

[0067] Total nitrogen (TN): Tested according to BSEN12260-2003 standard;

[0068] Ammonia nitrogen content: tested according to HJ / T195-2005 standard.

[0069] Example 1

[0070] The resource utilization treatment method for high-carbon alcohol waste alkali liquid described in this embodiment is as follows: Figure 1 As shown, the process includes the following steps: A 1000 kg / h flow rate of 2-pH waste alkaline solution (BOD5 / COD = 0.24, COD 60000 mg / L, conductivity 135500 μS·cm) -1The wastewater (pH=13.3) is discharged directly into the wastewater treatment system at a rate of 50 kg / h as added alkalinity, and 950 kg / h enters a homogenizing tank with a hydraulic retention time of 10 hours. The effluent from the homogenizing tank enters a pH adjustment tank, where waste acid is added to maintain the pH at approximately 3-5. The adjustment tank is cooled by circulating water to ensure the temperature does not exceed 65°C. The acidified wastewater then enters a chromatography system operating at atmospheric pressure and 65°C. The aqueous phase from the bottom of the chromatography tank is discharged into the wastewater treatment system, while the organic phase from the top is pressurized by a booster pump and sent to an ultraviolet (UV) treatment system for UV photocatalytic oxidation. The UV treatment system includes a power supply, UV lamps, and a reaction tube. A quartz sleeve is installed inside the reaction tube, and the UV lamps are installed inside the quartz sleeve. The area outside the quartz sleeve is the wastewater zone. The UV wavelength is 170-300 nm, and the UV power is 2000 W / m². 3 The ultraviolet reaction temperature is 60℃, and the hydraulic retention time in the wastewater area of ​​the reaction tube is 70s.

[0071] The organic phase after UV photocatalytic oxidation treatment is sent to the anoxic tank of the wastewater treatment system as an external carbon source. It is mixed with other wastewater (BOD5 / TN value less than 3, COD 480 mg / L, total nitrogen 105 mg / L, ammonia nitrogen 78 mg / L) at a volume ratio of 1:165. The hydraulic retention time in the anoxic tank is 0.5 h, and the dissolved oxygen concentration in the anoxic tank is 0.3 mg / L. The wastewater treated by denitrification in the anoxic tank enters the aerobic tank for nitrification treatment. The hydraulic retention time in the aerobic tank is 4 h, and the dissolved oxygen concentration in the aerobic tank is 4 mg / L. Part of the nitrified effluent is returned to the anoxic tank at a return ratio of 3-5. The remaining effluent enters the sedimentation tank for sedimentation and separation. The hydraulic retention time in the sedimentation tank is 2 h. Part of the sludge is returned to the anoxic tank at a return ratio of 0.3-0.5. The supernatant is discharged as effluent.

[0072] After testing, the organic phase BOD5 / COD ratio after UV catalytic oxidation treatment was 0.73, and the COD was 48,000 mg / L. The COD of the mixed influent after adding it as a carbon source was 555 mg / L. The COD of the effluent was 15 mg / L, the COD removal rate was 97.3%, the total nitrogen content was 8 mg / L, and the ammonia nitrogen content was 5 mg / L.

[0073] Example 2

[0074] The resource utilization treatment method for high-carbon alcohol waste alkali liquid described in this embodiment is as follows: Figure 1 As shown, the process includes the following steps: A 1000 kg / h 2-pH waste alkaline solution (BOD5 / COD = 0.29, COD = 100000 mg / L, conductivity 150000 μS·cm) -1The wastewater (pH=13.5) enters a homogenizing tank, with a preferred hydraulic retention time of 5 hours. The effluent from the homogenizing tank enters a pH adjustment tank, where waste acid is added to maintain the pH at approximately 3-5. Circulating water is circulated through the adjustment tank for cooling, ensuring the temperature does not exceed 65℃. The acidified wastewater then enters a chromatography system, operating at atmospheric pressure and 25℃. The aqueous phase from the bottom of the chromatography system is discharged into the wastewater treatment system, while the organic phase from the top is pressurized by a booster pump and sent to an ultraviolet (UV) treatment system for UV photocatalytic oxidation. The UV treatment system includes a power supply, UV lamps, and a reaction tube. The reaction tube includes a quartz sleeve area and a wastewater area. The UV wavelength of the UV treatment system is 170-300 nm, and the UV power is 2000 W / m². 3 The ultraviolet reaction temperature is 55℃, and the hydraulic retention time in the wastewater area of ​​the reaction tube is 90s.

[0075] The organic phase after UV photocatalytic oxidation treatment is sent as an external carbon source to the anoxic tank of the wastewater treatment system. It is mixed with other wastewater (BOD5 / TN value less than 3, COD 450 mg / L, total nitrogen 75 mg / L, ammonia nitrogen 65 mg / L) at a volume ratio of 1:330. The hydraulic retention time in the anoxic tank is 1 hour, and the dissolved oxygen concentration in the anoxic tank is 0.2 mg / L. The wastewater treated in the anoxic tank enters the aerobic tank for nitrification treatment. The hydraulic retention time in the aerobic tank is 6 hours, and the dissolved oxygen concentration in the aerobic tank is 6 mg / L. Part of the nitrified effluent is returned to the anoxic tank at a return ratio of 3-5. The remaining effluent enters the sedimentation tank for sedimentation and separation. The hydraulic retention time in the sedimentation tank is 3 hours. Part of the sludge is returned to the anoxic tank at a return ratio of 0.3-0.5. The supernatant is discharged as effluent.

[0076] After testing, the BOD5 / COD ratio of the organic phase after UV catalytic oxidation treatment was 0.65, and the COD was 70,000 mg / L. The COD of the mixed influent after adding it as a carbon source was 558 mg / L. The COD of the effluent was 12 mg / L, the COD removal rate was 97.8%, the total nitrogen content was 5 mg / L, and the ammonia nitrogen content was 2 mg / L.

[0077] Example 3

[0078] The resource utilization treatment method for high-carbon alcohol waste alkali liquid described in this embodiment is as follows: Figure 1 As shown, the process includes the following steps: a 1000 kg / h butanol / octanol waste alkaline solution (BOD5 / COD=0.25, COD is 43350 mg / L, conductivity is 90900 μS·cm) -1(pH=13.1), of which 50 kg / h is directly discharged into the wastewater treatment plant's biological treatment unit as external alkalinity, and 950 kg / h enters the homogenization tank. The hydraulic retention time is preferably 10 hours. The effluent from the homogenization tank enters the pH adjustment tank, where waste acid is mixed in to control the pH value at around 3-5. Circulating water is circulated through the side of the adjustment tank for cooling, and the temperature in the tank is controlled not to exceed 65℃. The acidified waste liquid enters the chromatography system, which operates at atmospheric pressure and 45℃. The aqueous phase at the bottom of the chromatography system is discharged into the wastewater treatment plant, and the organic phase at the top is pressurized by a booster pump and sent to the ultraviolet (UV) treatment system for UV photocatalytic oxidation treatment. The UV treatment system includes a power supply, UV lamps, and a reaction tube. The reaction tube includes a quartz sleeve area and a wastewater area. The UV wavelength of the UV treatment system is 170-300 nm, and the power is 1500 W / m. 3 The ultraviolet reaction temperature is 60℃, and the hydraulic retention time in the wastewater area of ​​the reaction tube is 50s.

[0079] The organic phase after UV photocatalytic oxidation treatment is sent to the anoxic tank of the wastewater treatment system as an external carbon source. It is mixed with other wastewater (BOD5 / TN value less than 3, COD 395 mg / L, total nitrogen 70 mg / L, ammonia nitrogen 60 mg / L) at a volume ratio of 1:170. The hydraulic retention time in the anoxic tank is 2 hours, and the dissolved oxygen concentration in the anoxic tank is 0.1 mg / L. The wastewater treated in the anoxic tank enters the aerobic tank for nitrification treatment. The hydraulic retention time in the aerobic tank is 5 hours, and the dissolved oxygen concentration in the aerobic tank is 5 mg / L. Part of the nitrified effluent is returned to the anoxic tank at a return ratio of 3-5. The remaining effluent enters the sedimentation tank for sedimentation and separation. The hydraulic retention time in the sedimentation tank is 4 hours. Part of the sludge is returned to the anoxic tank at a return ratio of 0.3-0.5. The supernatant is discharged as effluent.

[0080] After testing, the organic phase after UV catalytic oxidation treatment had a BOD5 / COD ratio of 0.82 and a COD of 33,000 mg / L. The COD of the mixed influent after adding the carbon source was 446 mg / L. The COD of the effluent was 6.7 mg / L, with a COD removal rate of 98.5%. The total nitrogen content was 5 mg / L, and the ammonia nitrogen content was 3 mg / L.

[0081] Comparative Example 1

[0082] The wastewater treatment process is the same as in Example 1, the only difference being the use of acetic acid as an external carbon source. Details are as follows:

[0083] Acetic acid is added as an external carbon source and sent to the anoxic tank of the wastewater treatment system. It is mixed with the wastewater (BOD5 / TN value less than 3, COD 480 mg / L, total nitrogen 105 mg / L, ammonia nitrogen 78 mg / L) introduced from the inlet at a volume ratio of 1:165. The hydraulic retention time in the anoxic tank is 0.5 h, and the dissolved oxygen concentration in the anoxic tank is 0.3 mg / L. The wastewater treated by denitrification in the anoxic tank enters the aerobic tank for nitrification treatment. The hydraulic retention time in the aerobic tank is 4 h, and the dissolved oxygen concentration in the aerobic tank is 4 mg / L. Part of the nitrified effluent is returned to the anoxic tank at a return ratio of 3-5. The remaining effluent enters the sedimentation tank for sedimentation and separation. The hydraulic retention time in the sedimentation tank is 2 h. Part of the sludge is returned to the anoxic tank at a return ratio of 0.3-0.5. The supernatant is discharged as effluent.

[0084] The test results showed that the COD of the effluent was 42 mg / L, the COD removal rate was 91.3%, the total nitrogen content was 15 mg / L, and the ammonia nitrogen content was 10 mg / L.

[0085] Comparative Example 2

[0086] The wastewater treatment process is the same as in Example 2, the only difference being the use of acetic acid as an external carbon source. Details are as follows:

[0087] Acetic acid is added as an external carbon source and sent to the anoxic tank of the wastewater treatment system. It is mixed with the wastewater (BOD5 / TN value less than 3, COD 450 mg / L, total nitrogen 75 mg / L, ammonia nitrogen 65 mg / L) entering through the inlet at a volume ratio of 1:330. The hydraulic retention time in the anoxic tank is 1 hour, and the dissolved oxygen concentration in the anoxic tank is 0.2 mg / L. The wastewater treated in the anoxic tank enters the aerobic tank for nitrification treatment. The hydraulic retention time in the aerobic tank is 6 hours, and the dissolved oxygen concentration in the aerobic tank is 6 mg / L. Part of the nitrified effluent is returned to the anoxic tank at a return ratio of 3-5. The remaining effluent enters the sedimentation tank for sedimentation and separation. The hydraulic retention time in the sedimentation tank is 3 hours. Part of the sludge is returned to the anoxic tank at a return ratio of 0.3-0.5. The supernatant is discharged as effluent.

[0088] The test results showed that the COD of the effluent was 55 mg / L, the COD removal rate was 87.8%, the total nitrogen was 11 mg / L, and the ammonia nitrogen content was 6 mg / L.

[0089] Comparative Example 3

[0090] The wastewater treatment process is the same as in Example 3, the only difference being the use of sodium acetate as an external carbon source. Details are as follows:

[0091] Sodium acetate was added as an external carbon source and sent to the anoxic tank of the wastewater treatment system. It was mixed with the wastewater (BOD5 / TN value less than 3, COD 395 mg / L, total nitrogen 70 mg / L, ammonia nitrogen 60 mg / L) at a volume ratio of 1:170. The hydraulic retention time in the anoxic tank was 2 hours, and the dissolved oxygen concentration in the anoxic tank was 0.1 mg / L. The wastewater treated in the anoxic tank entered the aerobic tank for nitrification treatment. The hydraulic retention time in the aerobic tank was 5 hours, and the dissolved oxygen concentration in the aerobic tank was 5 mg / L. Part of the nitrified effluent was returned to the anoxic tank at a return ratio of 3-5. The remaining effluent entered the sedimentation tank for sedimentation and separation. The hydraulic retention time in the sedimentation tank was 4 hours. Part of the sludge was returned to the anoxic tank at a return ratio of 0.3-0.5. The supernatant was discharged as effluent.

[0092] The test results showed that the COD of the effluent was 45 mg / L, the COD removal rate was 88.6%, the total nitrogen content was 10 mg / L, and the ammonia nitrogen content was 7 mg / L.

[0093] Comparative Example 4

[0094] This comparative example uses conventional treatment processes to treat waste alkaline solution, and the treated waste alkaline solution is then fed into a wastewater treatment system. The specific steps include: 1000 kg / h of 2-pH waste alkaline solution (BOD5 / COD = 0.24, COD 60000 mg / L, conductivity 135500 μS·cm) -1 The waste alkaline solution (pH=13.3) was diluted 500 times with a large amount of water. Industrial sulfuric acid was added to the diluted solution for neutralization, controlling the pH to around 3-5. This solution was then sent to the anoxic tank of the AO process in the wastewater treatment system, where it was mixed with other wastewater (BOD5 / TN value less than 3, COD 450 mg / L, total nitrogen 70 mg / L, ammonia nitrogen 60 mg / L) fed through the inlet. Acetic acid was used as an external carbon source. The hydraulic retention time in the anoxic tank was 2 hours. The dissolved oxygen concentration in the anoxic tank is 0.1 mg / L. Wastewater treated in the anoxic tank enters the aerobic tank for nitrification. The hydraulic retention time in the aerobic tank is 5 hours, and the dissolved oxygen concentration in the aerobic tank is 5 mg / L. Part of the nitrified effluent is returned to the anoxic tank at a return ratio of 3-5. The remaining effluent enters the sedimentation tank for sedimentation and separation. The hydraulic retention time in the sedimentation tank is 4 hours. Part of the sludge is returned to the anoxic tank at a return ratio of 0.3-0.5. The supernatant is discharged as effluent.

[0095] Testing revealed that the BOD5 / COD ratio of the waste alkaline solution after dilution and neutralization with industrial sulfuric acid was 0.52; the effluent COD was 80 mg / L, total nitrogen was 55 mg / L, and ammonia nitrogen was 35 mg / L, far below the GB31571 direct discharge standard. Furthermore, the effluent COD and total nitrogen showed a significant upward trend over time, reaching 118 mg / L and 67 mg / L after 7 days, comparable to the COD and total nitrogen of the diluted influent.

[0096] A comparison of Examples 1-3 and Comparative Examples 1-3 shows that, compared with traditional carbon sources such as acetic acid and sodium acetate, the novel carbon source obtained in these examples has a stronger promoting effect on microbial denitrification. After adding the AO biological treatment device, the effluent quality is better and the denitrification effect is stronger. Comparative Example 4 used conventional treatment processes to treat the waste alkaline solution, and the results showed that the effluent quality did not meet the direct discharge standards. Therefore, it can be seen that the wastewater obtained after the high-carbon alcohol waste alkaline solution of this invention undergoes special water homogenization-acidification-ultraviolet oxidation treatment has a BOD5 / COD ratio of 0.65-0.82, significantly enhancing its biodegradability, and can be used as a novel carbon source.

[0097] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for the resource-based treatment of high-carbon alcohol waste alkaline solution, characterized in that, Includes the following steps: (1) Waste alkaline solution is homogenized for water quality; (2) Add waste acid to the homogenized waste alkaline solution for acidification treatment; (3) The acidified waste liquid is sent to a chromatography system for phase separation, the aqueous phase is sent to the wastewater treatment system, and the organic phase is sent to the ultraviolet treatment system for ultraviolet photocatalytic oxidation treatment. (4) The organic phase after ultraviolet photocatalytic oxidation in step (3) is sent to the anoxic tank of the sewage treatment system as an external carbon source and mixed with other wastewater. The wastewater treated in the anoxic tank enters the aerobic tank for nitrification. Part of the nitrified effluent is returned to the anoxic tank, and the remaining effluent enters the sedimentation tank for sedimentation and separation. Part of the sludge is returned to the anoxic tank, and the supernatant is discharged as effluent.

2. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, In step (1), the water homogenization time is 1h-10h.

3. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, In step (2), the pH value of the waste liquid after acidification is 3-5, and the temperature of acidification is ≤65℃.

4. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, In step (3), the operating pressure of the chromatography unit is atmospheric pressure and the operating temperature is 15℃-65℃.

5. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, In step (3), the ultraviolet treatment system includes a power supply, an ultraviolet lamp and a reaction tube. A quartz sleeve is installed inside the reaction tube, and the ultraviolet lamp is installed inside the quartz sleeve. The area outside the quartz sleeve is a sewage area. Based on the influent, the effective volume of the reaction tube meets the requirement of a hydraulic retention time of 50s-100s.

6. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, In step (3), the operating conditions of the ultraviolet treatment system are: the ultraviolet reaction temperature is 55℃-60℃ and the ultraviolet wavelength is 170nm-300nm.

7. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, In step (4), the BOD5 / TN value of other wastewater is less than 3.

8. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, In step (4), the pH of the wastewater treatment system is 6-9 and the sludge age is 15-18 days; the reflux ratio of the nitrified effluent is 3-5 and the reflux ratio of the sedimentation tank sludge is 0.3-0.

5.

9. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, The method satisfies one or more of the following characteristics: In step (4), the hydraulic retention time of the anoxic tank is 0.5h-2h; In step (4), the hydraulic retention time of the aerobic tank is 4h-6h; In step (4), the hydraulic retention time of the sedimentation tank is 2h-4h; In step (4), the dissolved oxygen concentration in the anoxic pool is 0.1 mg / L-0.3 mg / L; In step (4), the dissolved oxygen concentration in the aerobic tank is 4 mg / L-6 mg / L.

10. The method for resource-based treatment of high-carbon alcohol waste alkaline solution according to claim 1, characterized in that, The steps also include sending a portion of the unhomogenized waste alkaline solution directly to the aerobic tank of the wastewater treatment system as an added alkalinity.

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