A method for treating antibiotic bacterial residue based on wet oxidation

Abstract

The application discloses an antibiotic bacterial residue treatment method based on wet oxidation, aiming at realizing the synergy of harmless disposal and high-value resource recovery of antibiotic bacterial residue. The method mixes antibiotic bacterial residue and water according to a specific ratio, and then places the mixture in a pressure reactor to carry out a wet oxidation reaction under preset temperature, reaction time and oxygen pressure conditions. The method can completely degrade the residual antibiotics in the bacterial residue, achieving the harmless treatment of hazardous waste; at the same time, the solid residue amount is significantly reduced, and the organic matter in the bacterial residue can be directionally converted into volatile fatty acids mainly in acetic acid, realizing the efficient recovery of high-value carbon source. The application has both environmental benefits and economic value, and provides an efficient and feasible technical scheme for the resource utilization of antibiotic bacterial residue.

Description

Technical Field

[0001] This invention belongs to the field of biomass solid waste resource utilization and treatment technology, specifically relating to a method for treating antibiotic bacterial residue based on wet oxidation. Background Technology

[0002] Antibiotic fermentation residue is a typical organic solid waste generated during the industrial production of antibiotics. Its main components include the mycelium of antibiotic-producing bacteria and its degradation products, unused culture medium and its degradation products, and residual antibiotics. As a type of biomass waste, fresh antibiotic fermentation residue not only readily ferments to produce malodorous gases containing compounds such as pyridine and pyrrole, but also typically contains residual antibiotics at concentrations exceeding 1000 mg / L. When these residual antibiotics are exposed to the environment, they can harm the physiological functions of plants and animals through ecotoxicological effects and may also induce the emergence of antibiotic-resistant bacteria.

[0003] Currently, incineration remains the primary method for disposing of antibiotic bacterial residue. However, due to the generally high moisture content and low calorific value of the residue, a significant amount of energy is required for pre-drying before incineration, and additional auxiliary fuel is needed to maintain the combustion temperature, resulting in high overall operating costs. While biological treatment methods such as composting and anaerobic digestion have been applied to some extent to reduce energy consumption and costs, their degradation of residual antibiotics is often incomplete, posing environmental risks such as antibiotic residues, the spread of resistance genes, and secondary pollution.

[0004] To address the aforementioned issues, recent research has gradually shifted towards chemical treatment methods. Existing technologies largely rely on externally applied strong oxidants or strong acids to assist digestion (e.g., CN202211184345.8, CN115475822B), or focus on non-oxidizing or low-temperature hydrothermal pretreatment technologies, with relatively limited attention paid to oxidative hydrothermal treatment—i.e., wet oxidation technology. The wet oxidation process involves the synergistic effects of multiple parameters such as temperature, time, and oxygen partial pressure, which exhibit complex coupling relationships, jointly regulating the reaction pathway and material conversion efficiency. However, a systematic study has yet been conducted on a wet oxidation process for achieving complete harmlessness and efficient resource recovery of antibiotic bacterial residue. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for treating antibiotic bacterial residue based on wet oxidation. By systematically optimizing key process parameters, this method achieves efficient, harmless, reduced-volume, and resource-based treatment of the bacterial residue, effectively solving the problems of high treatment cost, incomplete antibiotic degradation, and lack of resource utilization pathways in existing technologies.

[0006] Specifically, this invention provides a method for treating antibiotic bacterial residue based on wet oxidation, comprising the following steps: S1. The antibiotic bacterial residue to be treated is mixed and diluted with water to obtain a mixed slurry; S2. The mixed slurry is placed in a pressure reaction device and subjected to a wet oxidation reaction at a temperature of 200-260℃ and an initial oxygen pressure of 1-1.5MPa. S3. The reaction products are subjected to solid-liquid separation, and the resulting liquid product is collected as a biocarbon source.

[0007] In some specific embodiments of the present invention, the chemical oxygen demand of the mixed slurry is controlled at 10-50 g / L.

[0008] In some specific embodiments of the present invention, the reaction time of the wet oxidation reaction is 1-3 hours.

[0009] In some specific embodiments of the present invention, the solid-liquid separation adopts a three-phase separation process, the separated solid phase is non-toxic sludge residue, and the liquid phase is an aqueous solution rich in volatile fatty acids; wherein, no antibiotic residues were detected in either the solid phase or the liquid phase.

[0010] In some specific embodiments of the present invention, the volatile fatty acid includes acetic acid.

[0011] The present invention also provides a biocarbon source, which is prepared by the antibiotic bacterial residue treatment method based on wet oxidation as described in any of the above claims.

[0012] In some specific embodiments of the present invention, the biocarbon source is liquid.

[0013] In some specific embodiments of the present invention, the biocarbon source is rich in volatile fatty acids and contains no detectable antibiotic residues.

[0014] The present invention also provides the application of the above-described method for treating antibiotic bacterial residue based on wet oxidation in the disposal of hazardous antibiotic bacterial residue and the simultaneous preparation of liquid biocarbon source.

[0015] The present invention has the following significant advantages and effects compared with the prior art: (1) High efficiency and harmlessness: Under optimized process conditions, residual antibiotics are completely degraded, thus eliminating their environmental risks.

[0016] (2) Significant volume reduction: The total suspended solids removal rate of the system exceeds 85%, which greatly reduces the solids load of the final disposal.

[0017] (3) High-quality resource utilization: The wet oxidation process converts the organic matter in the bacterial residue into volatile fatty acids, mainly acetic acid, which accounts for more than 50% of the dissolved organic matter. It has good biochemical properties and can be used as a carbon source for the denitrification process of wastewater.

[0018] (4) Simultaneous reduction of pollutants: While degrading antibiotics and transforming organic matter, the chemical oxygen demand and total nitrogen content of the system are reduced by more than 75%, achieving synergistic removal of pollutants.

[0019] (5) In-situ resource recycling: The method of the present invention is particularly suitable for implementation within antibiotic manufacturers, realizing the in-situ conversion of bacterial residue into a liquid carbon source with utilization value, and has good technical and economic feasibility and prospects for promotion and application.

[0020] (6) No catalyst required: No catalyst is required. While achieving efficient and harmless treatment of antibiotic residue, the complexity of the process and operating costs are effectively reduced, and the risk of secondary pollution caused by the use of catalysts is avoided, ensuring the purity and safety of the resource products. Attached Figure Description

[0021] Appendix Figure 1 This is a process flow diagram of the method described in this invention.

[0022] Appendix Figure 2 The removal rates of conventional chemical indicators were obtained for the embodiments and comparative examples of this invention.

[0023] Appendix Figure 3 The acetic acid content, volatile fatty acid content, and the ratio of volatile fatty acids to the chemical oxygen demand of the oxidation liquid obtained in the embodiments and comparative examples of the present invention are given. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0025] According to the present invention, a method for treating antibiotic bacterial residue based on wet oxidation is provided, comprising the following steps: Step one involves mixing and diluting the antibiotic residue to be treated with water at a certain ratio to prepare a mixed slurry with a chemical oxygen demand (COD) of 10-50 g / L. Within this concentration range, the sludge particles are fully liquefied, and the organic matter content is high, resulting in a volatile suspended particle removal rate of more than 70% compared to the substrate suspension. The slurry also has suitable fluidity, which helps to achieve sufficient liquefaction and efficient mass transfer of sludge particles in subsequent reactions.

[0026] Step 2: Transfer the mixed slurry obtained in Step 1 to a pressure reactor and carry out wet oxidation treatment under the set temperature (200-260℃), pressure (initial oxygen pressure of 1-1.5MPa) and time conditions.

[0027] Step 3: After the reaction is complete, the liquid product rich in volatile fatty acids is collected by three-phase separation. This product can be used directly as a high-quality biocarbon source.

[0028] The process flow diagram is attached. Figure 1 As shown.

[0029] Example 1: Treatment of spectinomycin bacterial residue The bacterial residue produced by a spectinomycin (an antibiotic) manufacturing plant had an initial moisture content of 67.5%, a total chemical oxygen demand (COD) of 377.2 g / L, and a residual spectinomycin concentration of 743 mg / L. The treatment steps for the spectinomycin bacterial residue based on wet oxidation are as follows: Step 1: Mix and dilute the spectinomycin bacterial residue to be treated with deionized water at a mass ratio of 1:11 to prepare a mixed slurry with a chemical oxygen demand of 10-50 g / L.

[0030] Step 2: Transfer the mixed slurry obtained in Step 1 to a pressure reactor and carry out wet oxidation treatment under the conditions of reaction temperature 260℃, reaction time 2 h, and initial oxygen pressure 1.2 MPa (relative pressure).

[0031] Step 3: The reaction products are separated into solution, residue and gas by a three-phase separation device. The solution rich in volatile fatty acids flows out from the top of the device and can be used directly as a high-quality biological carbon source; the sludge residue is discharged from the bottom of the device; and the gas (carbon dioxide and unreacted oxygen) is discharged from the top.

[0032] The treated liquid products and sludge residue were analyzed by high-performance liquid chromatography (HPLC), and no spectinomycin was detected in either, indicating that the residual antibiotics had been completely degraded. The concentration of volatile fatty acids in the liquid phase exceeded 3.7 g / L, accounting for more than 50% of the organic matter in the liquid phase. This treatment process achieves significant volume reduction and harmlessness while maximizing the retention of organic matter, efficiently converting it into products with high resource value.

[0033] Example 2: Treatment of bacterial residue from an antibiotic pharmaceutical factory The company's average monthly production of antibiotic raw materials is approximately 5 tons, and during the production process, about 50 tons of antibiotic bacterial residue are generated monthly. This residue has a moisture content as high as 90%, a chemical oxygen demand (COD) of approximately 300 g / kg, and a total nitrogen content of approximately 45 g / kg. The steps for treating the bacterial residue from the antibiotic pharmaceutical plant based on wet oxidation are as follows: Step 1: Mix and dilute the spectinomycin bacterial residue to be treated with deionized water at a mass ratio of 1:10 to prepare a mixed slurry with a chemical oxygen demand of 10-50 g / L.

[0034] Step 2: Transfer the mixed slurry obtained in Step 1 to a pressure reactor and carry out wet oxidation treatment under the conditions of reaction temperature 260℃, reaction time 2 h, and initial oxygen pressure 1.2 MPa (relative pressure).

[0035] Step 3: The reaction products are separated into solution, residue and gas by a three-phase separation device. The solution rich in volatile fatty acids flows out from the top of the device and can be used directly as a high-quality biological carbon source; the sludge residue is discharged from the bottom of the device; and the gas (carbon dioxide and unreacted oxygen) is discharged from the top.

[0036] This process not only achieves complete harmlessness of waste, but also yields approximately 500,000 liters of oxidizing liquid per month. The resulting liquid product has a chemical oxygen demand of approximately 7.5 g / L and a total nitrogen concentration of approximately 1.1 g / L.

[0037] Comparative Example 1: Treatment of spectinomycin bacterial residue with different process parameters Comparative experiments were conducted using spectinomycin residue, which is the same as that used in Example 1, under different conditions.

[0038] The reaction was carried out at a reaction temperature of 180 °C, a reaction time of 2 h, and an oxygen pressure of 1.2 MPa (Comparative Example 1). The resulting oxidation liquid had a chemical oxygen demand of approximately 10.8 g / L, and a total solids removal rate of only 54.7%. Due to the relatively low temperature and insufficient energy in the reaction system, the oxidation reaction was incomplete, and a large amount of organic matter remained in the solid phase, resulting in poor volume reduction. Furthermore, the concentration of volatile fatty acids in the liquid phase was only about 2.8 g / L, accounting for only 26% of the organic matter in the liquid phase, indicating low resource utilization value.

[0039] Comparative Example 2: Treatment of spectinomycin bacterial residue with different process parameters Comparative experiments were conducted using spectinomycin residue, which is the same as that used in Example 1, under different conditions.

[0040] The reaction was carried out at a temperature of 260 °C, a reaction time of 0.5 h, and an oxygen pressure of 1.2 MPa (Comparative Example 2). Despite the significant increase in temperature, the reaction time was too short, resulting in insufficient oxidation. The resulting oxidized liquid had a chemical oxygen demand (COD) of approximately 11.6 g / L and a total solids removal rate of 68.9%. Although this was an improvement over Comparative Example 1, it still indicated a relatively high amount of residual organic matter in the solids. Simultaneously, the concentration of volatile fatty acids in the liquid phase was approximately 2.5 g / L, accounting for approximately 21.6% of the organic matter in the liquid phase. The high-temperature, short-duration conditions were even more unfavorable for the formation and accumulation of volatile fatty acids, further reducing the recyclability of the liquid phase resources.

[0041] Comparative Example 3: Treatment of spectinomycin bacterial residue with different process parameters Comparative experiments were conducted using spectinomycin residue, which is the same as that used in Example 1, under different conditions.

[0042] The reaction was carried out under harsh conditions of 260 °C, 4 h, and 1.2 MPa oxygen pressure (Comparative Example 3). The resulting oxidant had a chemical oxygen demand of approximately 5.9 g / L and a total solids removal rate of 86%. Although the volume reduction effect was comparable to that of the previous example, the excessively long reaction time resulted in over 80% of the organic matter being over-oxidized to CO2, and the acetic acid content was hardly increased. The process was energy-intensive and had a reduced resource utilization rate.

[0043] The comparison data of the treatment effects of Example 1 and Comparative Examples 1–3 are attached as follows. Figure 2 and attached Figure 3 As shown. (Attached) Figure 2 The removal rates of each scheme in terms of conventional chemical indicators (such as COD, TOC, and total solids) are shown; Appendix Figure 3 The results show the acetic acid content, total volatile fatty acid (VFA) content, and their proportion of the chemical oxygen demand (COD) in the oxidation solution.

[0044] The results showed that under the wet oxidation process conditions of the present invention (reaction temperature 260℃, reaction time 12 h, oxygen partial pressure 1.2 MPa (gauge pressure)), the antibiotic degradation rate reached 100% and no residue was detected; the total solids (TS) removal rate exceeded 85%, and the volume reduction effect was significant.

[0045] More importantly, the volatile fatty acids (VFAs) in the liquid products after the reaction account for more than 50% of the total organic matter (based on COD), with acetic acid being the main component. This effluent has excellent biodegradability and can be directly used as a high-quality external carbon source for denitrification bioreactors.

[0046] In contrast, Comparative Example 1 (low temperature conditions) showed incomplete antibiotic degradation, a low total solids removal rate, and insufficient VFA yield, failing to meet the requirements for harmlessness and resource recovery. Comparative Example 2 (short reaction time conditions) effectively removed antibiotics, but the VFA yield was even lower, further reducing the recyclability of the liquid phase resources. While Comparative Example 3 achieved similar volume reduction results to the examples, the extended reaction time to 24 hours led to over-oxidation of more than 80% of the organic matter into CO2. During this process, the acetic acid content barely increased, indicating a reduced degree of resource recovery. Simultaneously, the excessively long reaction time significantly increased process energy consumption, reducing overall economic efficiency.

[0047] In summary, this invention, through precise control of wet oxidation reaction parameters, simultaneously achieves complete harmlessness (complete antibiotic degradation), efficient volume reduction (TS removal >85%), and targeted resource utilization (high VFA yield, usable as a carbon source) of antibiotic bacterial residue in a single treatment process. In contrast, although Comparative Example 3 achieved similar volume reduction effects, its excessively high energy consumption and low resource utilization efficiency prevent it from meeting the green, low-carbon, and high-value treatment goals pursued by this invention.

[0048] The above description is merely a preferred embodiment of this application and is used to illustrate the technical principles employed. It should be understood that the scope of protection of this application is not limited to the combination of the specific technical features described above. Without departing from the core concept of this invention, those skilled in the art can make various modifications, substitutions, or equivalent transformations to the above technical features, and can arbitrarily combine them with other technical features disclosed in this application (but not limited to) that have the same or similar functions, thereby forming a variety of implementable technical solutions, all of which should be considered to fall within the scope of protection of this invention.

Claims

1. A method for treating antibiotic bacterial residue based on wet oxidation, characterized in that, Includes the following steps: S1. Mix and dilute the antibiotic bacterial residue to be treated with water to obtain a mixed slurry; S2. The mixed slurry is placed in a pressure reaction device and subjected to a wet oxidation reaction at a temperature of 200-260℃ and an initial oxygen pressure of 1-1.5MPa. S3. The reaction products are subjected to solid-liquid separation, and the resulting liquid product is collected as a biocarbon source.

2. The method for treating antibiotic bacterial residue based on wet oxidation according to claim 1, characterized in that, The chemical oxygen demand of the mixed slurry is controlled at 10-50 g / L.

3. The method for treating antibiotic bacterial residue based on wet oxidation according to claim 1, characterized in that, The reaction time for the wet oxidation reaction is 1-3 hours.

4. A method for treating antibiotic bacterial residue based on wet oxidation according to any one of claims 1-3, characterized in that, The solid-liquid separation adopts a three-phase separation process. The separated solid phase is non-toxic sludge residue, and the liquid phase is an aqueous solution rich in volatile fatty acids. No antibiotic residues were detected in either the solid or liquid phase.

5. The method for treating antibiotic bacterial residue based on wet oxidation according to claim 4, characterized in that, The volatile fatty acids include acetic acid.

6. A biocarbon source, characterized in that, It is prepared by the method for treating antibiotic bacterial residue based on wet oxidation as described in any one of claims 1 to 5.

7. The biocarbon source as described in claim 6, characterized in that, The biocarbon source is in liquid form.

8. The biocarbon source according to any one of claims 6-7, characterized in that, The bio-carbon source is rich in volatile fatty acids and contains no detectable antibiotic residues.

9. The application of the antibiotic bacterial residue treatment method based on wet oxidation as described in any one of claims 1 to 5 in the disposal of hazardous antibiotic bacterial residue and the simultaneous preparation of liquid biocarbon source.

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