Method for driving anaerobic bioremediation of chlorinated hydrocarbons based on pbsa sustained release electron donor

Abstract

This invention discloses a method for anaerobic bioremediation of chlorinated hydrocarbons driven by PBSA as a slow-release electron donor, belonging to the field of in-situ bioremediation technology for soil and groundwater. The method is as follows: 1) A mixed dechlorination bacterial community containing obligate organohalogen-respiring bacteria and their symbiotic bacteria is cultured to the logarithmic growth phase to obtain a mixed dechlorination bacterial solution; 2) Anaerobic digested sludge is mixed evenly with the mixed dechlorination bacterial solution to obtain a mixed inoculum; 3) The mixed inoculum is added to groundwater contaminated with chlorinated hydrocarbons, and PBSA is added as a slow-release electron donor to drive the reductive dechlorination reaction of chlorinated hydrocarbons under anaerobic conditions, thereby removing the pollutants. This invention solves the problems of easy dilution and high risk of secondary pollution associated with traditional liquid carbon sources, as well as the high cost and low dechlorination efficiency of existing slow-release materials. Using PBSA as a slow-release electron donor results in an increasing dechlorination rate and high electron utilization efficiency. Industrial-grade PBSA is inexpensive, and this invention provides an efficient, green, and low-cost solution for in-situ remediation of chlorinated hydrocarbons in groundwater.

Description

Technical Field

[0001] This invention belongs to the field of in-situ bioremediation technology for soil and groundwater, specifically relating to a method for anaerobic bioremediation of chlorinated hydrocarbons driven by PBSA slow-release electron donors. Background Technology

[0002] Chlorinated hydrocarbons (such as trichloroethylene and tetrachloroethylene) are important chemical raw materials and organic solvents. Due to improper handling during industrial production, storage, transportation, and use, chlorinated hydrocarbons have become one of the most frequently detected persistent organic pollutants in groundwater worldwide. These compounds are characterized by high toxicity, strong carcinogenicity and teratogenicity, high mobility, and difficulty in natural degradation. They can enter the human body through drinking water and skin contact, seriously threatening the safety of groundwater ecosystems and human health.

[0003] For the pollution problem of chlorinated hydrocarbons in groundwater, in-situ bioremediation technology based on anaerobic dechlorination microorganisms can directly play a remediation role at contaminated sites, converting chlorinated hydrocarbons into non-toxic or low-toxic end products through gradual reduction and dechlorination. This technology has advantages such as environmental friendliness, no secondary pollution, and strong sustainability, and is currently the mainstream technology for remediating chlorinated hydrocarbon pollution in groundwater. However, in practical engineering applications, this technology still faces significant bottlenecks. Traditional liquid carbon sources (such as sodium lactate, methanol, and sodium acetate) are easily diluted and migrated rapidly in the seepage environment of groundwater, and are easily competitively consumed by native microorganisms, resulting in a short effective supply cycle of electron donors and difficulty in sustaining the remediation effect. In addition, excessive addition of liquid carbon sources may also cause excessive proliferation of aquifer microorganisms, causing pore blockage and bringing the risk of secondary pollution. Furthermore, the adsorption-desorption of chlorinated hydrocarbons by the aquifer medium can also lead to "tailing" and "rebound" phenomena of pollutants, significantly prolonging the remediation cycle and increasing the remediation cost.

[0004] To address the aforementioned issues, the addition of slow-release electron donors has become a core optimization strategy for in-situ bioremediation of chlorinated hydrocarbons in groundwater. Slow-release carbon source materials can slowly and continuously release small-molecule electron donors in the anaerobic environment of groundwater, maintaining the activity and abundance of dechlorination-functional microorganisms for a long period, thus meeting the long-term needs of in-situ groundwater remediation. However, existing slow-release material systems still have significant drawbacks: chemically synthesized slow-release materials such as tetrabutoxysilane (TBOS) are costly to prepare and difficult to scale up for engineering applications; vegetable oil-sugar composite slow-release materials have poor chemical stability, are prone to migration in groundwater, and have weak controllability of slow release; natural polymer materials such as straw and sawdust have poor mechanical properties, resulting in uncontrollable carbon source release and potential secondary pollution; and reducing materials such as nano-zero-valent iron have potential biotoxicity, with unclear long-term environmental risks.

[0005] In recent years, biodegradable polymers (BDPs) have become a research hotspot in the field of environmental remediation due to their advantages such as mature preparation processes, scalable industrial production, good biocompatibility, and strong controllability of degradation. In anaerobic groundwater environments, BDPs can be gradually depolymerized and fermented by functional microorganisms to generate small molecule products such as acetic acid and hydrogen, which can serve as high-quality electron donors in anaerobic dechlorination processes, possessing theoretical potential and application advantages as a slow-release carbon source. However, currently only a very small number of BDPs (such as polyhydroxybutyrate valerate (PHBV)) have been preliminarily explored for the dechlorination and remediation of chlorinated hydrocarbons. Systematic research on mainstream BDPs, which have larger industrial production volumes, lower costs, and superior degradation performance, in the field of anaerobic dechlorination of chlorinated hydrocarbons remains extremely scarce. No BDPs-based slow-release carbon source remediation technology that combines efficient dechlorination, long-term slow release, low cost, and easy scalability has yet been developed. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies by selecting polybutylene adipate (PBSA), a mainstream biodegradable industrial polymer, as a slow-release electron donor, and developing a complete technical method suitable for the anaerobic bioremediation of chlorinated hydrocarbons in groundwater. Specifically, it provides a method for anaerobic bioremediation of chlorinated hydrocarbons driven by PBSA slow-release electron donors.

[0007] The specific technical solution adopted in this invention is as follows:

[0008] This invention provides a method for anaerobic bioremediation of chlorinated hydrocarbons driven by PBSA sustained-release electron donors, the specific steps of which are as follows:

[0009] S1: The mixed dechlorination bacteria are cultured in an anaerobic enrichment medium to the logarithmic growth phase to obtain a mixed dechlorination bacterial solution; the mixed dechlorination bacteria are a mixed bacterial system containing obligate organic halogen-respiring bacteria and their symbiotic bacteria;

[0010] S2: After thoroughly mixing the anaerobic digested sludge with the mixed dechlorination bacterial solution, wash and starve culture to obtain the mixed inoculum;

[0011] S3: The mixed inoculum is added to groundwater contaminated with chlorinated hydrocarbons, and pretreated polybutylene adipate is added as a slow-release electron donor; under anaerobic conditions, organohalogen respiratory bacteria drive the reduction and dechlorination reaction of chlorinated hydrocarbons to remove chlorinated hydrocarbon pollutants from the groundwater.

[0012] Preferably, the obligate organohalogenating bacteria are *Dehalococcoides* sp.; and the symbiotic bacteria are methanogens.

[0013] Preferably, the mixed dechlorination bacterial community also includes functional bacteria that assist in dechlorination.

[0014] Furthermore, the functional bacteria used to assist in dechlorination are Geobacter sp.

[0015] Preferably, the anaerobic enrichment medium is as follows: trace element A solution and trace element B solution are added to the inorganic salt mother liquor, and then HEPES organic buffer and sodium bicarbonate solution are added to adjust the pH value to 7.2~7.5 to obtain the anaerobic enrichment medium.

[0016] Furthermore, the anaerobic enrichment medium contains the following per liter of inorganic salt stock solution: 1.0 g NaCl, 0.2 g KH₂PO₄, 0.3 g NH₄Cl, 0.3 g KCl, 0.015 g CaCl₂·2H₂O, and 0.06 g MgCl₂·6H₂O; per liter of trace element A solution: 0.006 g Na₂SeO₃·5H₂O, 0.008 g Na₂WO₄·2H₂O, and 0.5 g NaOH; per liter of trace element B solution: 1.500 g FeCl₂·4H₂O, 0.190 g CoCl₂·6H₂O, 0.100 g MnCl₂·4H₂O, 0.070 g ZnCl₂, 0.006 g H₃BO₃, 0.036 g Na₂MoO₄·2H₂O, 0.024 g NiCl₂·6H₂O, and 0.002 g NaOH. g CuCl2·2H2O and 10 mL of HCl solution with a mass concentration of 25%.

[0017] Preferably, the volume ratio of the anaerobic digested sludge and the mixed dechlorination bacterial solution in step S2 is controlled to be 1:(10~15).

[0018] Preferably, in step S2, the sample is washed with PBS buffer and then starved for 2 weeks.

[0019] As a preferred embodiment, the pretreatment method of the polybutylene adipate succinate in step S3 is as follows: industrial grade polybutylene adipate succinate is repeatedly washed with deionized water to remove impurities, and then dried at 30~50℃ to constant weight to obtain the pretreated PBSA slow-release carbon source.

[0020] Preferably, the chlorinated hydrocarbon pollutant is one or more of trichloroethylene, tetrachloroethylene, dichloroethylene, and vinyl chloride.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) In the groundwater treatment method provided by the present invention, polybutylene adipate (PBSA) is used as a slow-release electron donor. PBSA can be gradually depolymerized by microorganisms in an anaerobic environment, slowly and continuously releasing small molecule electron donors (such as acetic acid and hydrogen), effectively overcoming the defects of traditional liquid carbon sources that are easily diluted, migrated, and consumed by indigenous microorganisms, significantly extending the effective supply cycle of electron donors, and maintaining the activity and abundance of dechlorination functional microorganisms for a long time, thus achieving efficient and sustained degradation of chlorinated hydrocarbons.

[0023] (2) The method provided by this invention can drive the gradual reduction and dechlorination of chlorinated hydrocarbons (such as trichloroethylene) to the non-toxic final product ethylene, effectively avoiding the accumulation of the highly toxic intermediate product vinyl chloride (VC) and reducing the environmental and health risks during the remediation process. Electrons preferentially flow from the competitive methanogenesis pathway to the dechlorination process, avoiding the ineffective consumption of electrons, improving electron utilization efficiency and reducing carbon source addition costs.

[0024] (3) The method provided by this invention can treat groundwater pollution in situ. Through the long-term effect of slow-release electron donors, it enhances the continuous metabolic capacity of dechlorination microorganisms in groundwater, effectively solving the problems of easy dilution and short-term effect of traditional liquid carbon sources. At the same time, it inhibits the "tailing" and "rebound" phenomena of pollutants and improves the remediation stability.

[0025] (4) The PBSA used in this invention is a biodegradable material that can be naturally degraded in the environment after repair without introducing persistent harmful substances; at the same time, it avoids problems such as excessive proliferation of aquifer microorganisms and pore blockage that may be caused by excessive addition of liquid carbon source, and has the characteristics of green sustainability. Attached Figure Description

[0026] Figure 1 The kinetic curve of PBSA-driven TCE dechlorination in Example 1;

[0027] Figure 2 The kinetic curve of PHBV-driven TCE dechlorination in Comparative Example 1;

[0028] Figure 3 The kinetic curve of TCE dechlorination in Comparative Example 2 without the addition of a slow-release carbon source;

[0029] Figure 4 The curves showing the change in TOC concentration in the reaction systems of Example 1, Comparative Example 1, and Comparative Example 2 are shown.

[0030] Figure 5 The curves showing the change in methane concentration in the reaction systems of Example 1, Comparative Example 1, and Comparative Example 2 are shown. Detailed Implementation

[0031] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0032] The anaerobic digested sludge used in the following examples and comparative examples was derived from the anaerobic digester of an urban wastewater treatment plant.

[0033] The mixed dechlorination microbial community used was a commercially available microbial agent (KB-1, a commercial anaerobic dehalogenation microbial agent purchased from SiREM (Guelph, ON, Canada)), capable of dechlorinating trichloroethylene (TCE) to ethylene. This agent contained organohalogen-respiring bacteria, dechlorination-aiding functional bacteria, and symbiotic bacteria. The organohalogen-respiring bacteria were *Dehalococcoides* sp., the dechlorination-aiding functional bacteria were *Geobacter* sp., and the symbiotic bacteria were methanogenic *Methanomethylovorans* sp.

[0034] The polybutylene adipate (PBSA) and polyhydroxybutyrate valerate (PHBV) used are both industrial-grade commercial products.

[0035] Example 1

[0036] This embodiment provides a method for treating trichloroethylene (TCE) using PBSA as a carbon source, as detailed below:

[0037] (1) Pretreatment of PBSA sustained-release carbon source

[0038] Industrial-grade polybutylene adipate succinate (PBSA) was selected and repeatedly washed three times with deionized water to thoroughly remove surface impurities. The washed PBSA was then placed in a 40°C oven for low-temperature drying until the difference between two consecutive weighings did not exceed 0.001 g, i.e., dried to constant weight. Finally, it was sealed and stored for later use.

[0039] (2) Preparation of anaerobic enrichment medium

[0040] Prepare an inorganic salt mother liquor containing: 1.0 g NaCl, 0.2 g KH2PO4, 0.3 g NH4Cl, 0.3 g KCl, 0.015 g CaCl2·2H2O, and 0.06 g MgCl2·6H2O per liter;

[0041] Prepare a trace element A solution containing: 0.006 g Na2SeO3·5H2O, 0.008 g Na2WO4·2H2O, and 0.5 g NaOH per liter;

[0042] Prepare a trace element B solution, each liter containing: 1.500 g FeCl2·4H2O, 0.190 g CoCl2·6H2O, 0.100 g MnCl2·4H2O, 0.070 g ZnCl2, 0.006 g H3BO3, 0.036 g Na2MoO4·2H2O, 0.024 g NiCl2·6H2O, 0.002 g CuCl2·2H2O, and 10 mL of 25% HCl solution.

[0043] Take 10 mL of the above inorganic salt stock solution as the base solution, add 1 mL of trace element A solution and 1 mL of trace element B solution, then add HEPES organic buffer with a final concentration of 10 mM and NaHCO3 with a final concentration of 10 mM, adjust the pH value to 7.2~7.5, and obtain the anaerobic enrichment medium.

[0044] After the anaerobic enrichment medium was prepared, it was boiled for 20 min under nitrogen protection to remove dissolved oxygen. The medium was then dispensed into serum bottles, sealed, and autoclaved at 121°C for 30 min. 1 mL of a reducing agent solution containing 10 mM HEPES organic buffer and 10 mM NaHCO3 was injected to completely remove residual oxygen. The solution was allowed to stand until the redox potential Eh < -300 mV, after which the residual reducing agent was removed. Sterile multivitamin solution and vitamin B were then injected into the serum bottles. 12 Prepare the solution and adjust the headspace pressure inside the bottle to 101.3 ± 0.1 kPa.

[0045] (3) Pretreatment of inoculum

[0046] The mixed dechlorinating bacteria were inoculated into the above-mentioned anaerobic enrichment medium and cultured until the logarithmic growth phase to obtain the mixed dechlorinating bacteria solution.

[0047] The anaerobic digested sludge was then mixed with the mixed dechlorination bacterial solution at a volume ratio of 1:10 to obtain a mixed inoculum. Before inoculation, the mixed inoculum was washed three times with PBS buffer and then placed in a constant temperature anaerobic environment at 30°C for a two-week starvation culture to completely consume the endogenous substrate before use.

[0048] (4) Construction of anaerobic bioremediation system

[0049] In an anaerobic glove box (gas environment: a mixture of 20% CO2 and 80% N2 by volume), add 1 g of pretreated PBSA sustained-release carbon source and 5 mL of pretreated mixed inoculum to the pretreated serum bottle. Then, inject trichloroethylene (TCE) stock solution to set the TCE concentration in the system to 250 μM. After sealing the serum bottle and mixing thoroughly, place it in a 30°C incubator and incubate upside down in the dark. When the vinyl chloride (VC) concentration in the system drops below the detection limit of 0.5 μM, replenish TCE to 250 μM and start the next dechlorination cycle.

[0050] (5) Anaerobic dechlorination operation and monitoring

[0051] The anaerobic bioremediation system described above was cultured at a constant temperature of 30℃ in the dark for 52 days. During the culture period, headspace gas was collected periodically using an airtight syringe, and the concentration changes of TCE, its intermediate dechlorination products (dichloroethylene DCE and vinyl chloride VC), and the final product ethylene were analyzed by gas chromatography-FID. The results are as follows: Figure 1 As shown. The change in methane concentration during the reaction is as follows. Figure 5 As shown. Water samples were taken periodically, and the TOC concentration of the system was monitored using a TOC analyzer. The results are as follows. Figure 4 .

[0052] Comparative Example 1

[0053] This comparative example provides a method for treating trichloroethylene (TCE) using PHBV as a carbon source, as detailed below:

[0054] This comparative example used the exact same experimental conditions, system construction method, and culture parameters as Example 1, except that the sustained-release carbon source was replaced by the traditional BDPs sustained-release carbon source PHBV. All other operations were consistent with Example 1. The dechlorination kinetics results are as follows: Figure 2 TOC and methane concentrations are as follows: Figure 4 , 5 As shown.

[0055] Comparative Example 2

[0056] This comparative example provides a method for treating trichloroethylene (TCE) without adding a carbon source, as follows:

[0057] This comparative example used the exact same experimental conditions, system construction method, and culture parameters as Example 1, without adding any slow-release carbon source, and only inoculated with pretreated mixed inoculum. All other operations were consistent with Example 1. The dechlorination kinetics results are as follows: Figure 3 TOC and methane concentrations are as follows: Figure 4 , 5 As shown.

[0058] Depend on Figure 1 As can be seen, in the PBSA slow-release electron donor system of Example 1, the TCE concentration gradually decreases with reaction time and is further converted into ethylene via intermediates such as DCE and VC. Even with continuous TCE supplementation, the system can still restart and complete the reductive dechlorination process, indicating that PBSA can continuously provide electron donors for dechlorination-functional microorganisms under anaerobic conditions, enabling continuous and stable complete dechlorination of TCE. This demonstrates that the PBSA slow-release electron donor used in this invention can effectively maintain the activity of organohalogen respiring bacteria and has good long-term dechlorination capability.

[0059] Depend on Figure 2 As can be seen, in the PHBV system of Comparative Example 1, although TCE can undergo some degree of reductive dechlorination, the dechlorination process is relatively slow, and the intermediate product conversion is insufficient. Compared with Example 1, the conversion efficiency of TCE to ethylene in the PHBV system is lower, and the dechlorination continuity and stability are poorer. This result indicates that, compared with PHBV, PBSA, as a slow-release electron donor, is more conducive to promoting the complete reductive dechlorination of TCE and can achieve better dechlorination effect.

[0060] Depend on Figure 3 It is evident that the TCE dechlorination capacity was significantly insufficient in the Comparative Example 2 system without the addition of a slow-release carbon source. Due to the lack of a continuous external electron donor in the system, TCE could not be stably and completely converted into ethylene, indicating that relying solely on the residual substrate of the inoculum itself is insufficient to maintain a long-term and effective reductive dechlorination process. This result further demonstrates that a continuous and stable supply of electron donors is a crucial condition for achieving complete dechlorination in the anaerobic bioremediation of chlorinated hydrocarbons; this invention, by adding PBSA as a slow-release electron donor, can effectively overcome the problem of insufficient dechlorination capacity in the system without a carbon source.

[0061] Depend on Figure 4 As can be seen, the TOC concentration in the PBSA system of Example 1 remained relatively stable during the reaction, indicating that PBSA can gradually release organic carbon in the anaerobic system and maintain a relatively stable organic carbon level in the aqueous phase. In contrast, the TOC change stability of the PHBV system in Comparative Example 1 was poor, and the TOC level of Comparative Example 2 was low because no slow-release carbon source was added. These results show that PBSA has good slow-release carbon supply performance, which can avoid the problems of rapid release, rapid consumption, or easy migration with groundwater of traditional liquid carbon sources, thus providing a continuous and stable electron donor source for dechlorination microorganisms.

[0062] Depend on Figure 5As can be seen, methane generation in the PBSA system of Example 1 was effectively controlled, and no large amount of methane accumulated continuously. The amount of methane generated reflects the degree to which electron donors are competitively consumed by the methanogenesis process. Compared with the comparative system, the PBSA system, while promoting complete TCE dechlorination, reduced the ineffective consumption of electron donors in the methanogenesis pathway, indicating that the electron donors released by PBSA are more readily utilized by dechlorination-functional microorganisms. These results demonstrate that the present invention not only improves the reductive dechlorination efficiency of TCE but also optimizes the electron flow in the anaerobic system, thereby improving electron donor utilization efficiency.

[0063] comprehensive Figures 1 to 5 It is evident that this invention utilizes PBSA as a slow-release electron donor, enabling the continuous release of usable organic carbon under anaerobic conditions. This promotes the complete conversion of TCE to ethylene via DCE and VC, and maintains stable dechlorination capacity even under multiple rounds of TCE replenishment. Simultaneously, the PBSA system maintains a relatively stable TOC level, reducing the competitive consumption of electron donors caused by methane formation. Compared to the PHBV system and systems without added slow-release carbon sources, this invention offers advantages such as high dechlorination efficiency, low intermediate product accumulation, stable slow-release performance, high electron donor utilization, and strong long-term remediation capability, making it suitable for anaerobic bioremediation of groundwater contaminated with chlorinated hydrocarbons.

[0064] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for driving anaerobic bioremediation of chlorinated hydrocarbons based on PBSA sustained release electron donor, characterized in that, The specific steps are as follows: S1: The mixed dechlorination bacteria are cultured in an anaerobic enrichment medium to the logarithmic growth phase to obtain a mixed dechlorination bacterial solution; the mixed dechlorination bacteria are a mixed bacterial system containing obligate organic halogen-respiring bacteria and their symbiotic bacteria; S2: After thoroughly mixing the anaerobic digested sludge with the mixed dechlorination bacterial solution, wash and starve culture to obtain the mixed inoculum; S3: The mixed inoculum is added to groundwater contaminated with chlorinated hydrocarbons, and pretreated polybutylene adipate is added as a slow-release electron donor; under anaerobic conditions, organohalogen respiratory bacteria drive the reduction and dechlorination reaction of chlorinated hydrocarbons to remove chlorinated hydrocarbon pollutants from the groundwater.

2. The method of driving anaerobic bioremediation of chlorinated hydrocarbons using PBSA based slow release electron donor according to claim 1, characterized in that, The obligate organohalogenating bacteria are *Dehalococcoides* sp.; the symbiotic bacteria are methanogens.

3. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 1, characterized in that, The mixed dechlorination bacterial community also includes functional bacteria that assist in dechlorination.

4. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 3, characterized in that, The functional bacteria used to assist in dechlorination are Geobacter sp.

5. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 1, characterized in that, The anaerobic enrichment medium is as follows: add trace element A solution and trace element B solution to the inorganic salt mother liquor, and then add HEPES organic buffer and sodium bicarbonate solution to adjust the pH value to 7.2~7.5 to obtain the anaerobic enrichment medium.

6. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 5, characterized in that, The anaerobic enrichment medium contains the following per liter of inorganic salt stock solution: 1.0 g NaCl, 0.2 g KH₂PO₄, 0.3 g NH₄Cl, 0.3 g KCl, 0.015 g CaCl₂·2H₂O, and 0.06 g MgCl₂·6H₂O; per liter of trace element A solution: 0.006 g Na₂SeO₃·5H₂O, 0.008 g Na₂WO₄·2H₂O, and 0.5 g NaOH; per liter of trace element B solution: 1.500 g FeCl₂·4H₂O, 0.190 g CoCl₂·6H₂O, 0.100 g MnCl₂·4H₂O, 0.070 g ZnCl₂, 0.006 g H₃BO₃, 0.036 g Na₂MoO₄·2H₂O, 0.024 g NiCl₂·6H₂O, and 0.002 g... 10 mL of CuCl2·2H2O and 25% HCl solution.

7. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 1, characterized in that, In step S2, the volume ratio of anaerobic digested sludge to mixed dechlorination bacterial solution is controlled to be 1:(10~15).

8. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 1, characterized in that, In step S2, the cells were washed with PBS buffer and then starved for 2 weeks.

9. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 1, characterized in that, The pretreatment method of polybutylene adipate succinate in step S3 is as follows: industrial grade polybutylene adipate succinate is repeatedly washed with deionized water to remove impurities, and then dried at 30~50℃ to constant weight to obtain pretreated PBSA slow-release carbon source.

10. The method for anaerobic bioremediation of chlorinated hydrocarbons based on PBSA slow-release electron donors according to claim 1, characterized in that, The chlorinated hydrocarbon pollutant is one or more of trichloroethylene, tetrachloroethylene, dichloroethylene, and vinyl chloride.

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