CN105194831B - A kind of electro photoluminescence promotes the method that volatile chlorinated hydrocarbon biological reducing decomposes - Google Patents

Abstract

The invention relates to a method for promoting the biological reduction and decomposition of volatile chlorinated hydrocarbons by electrical stimulation, and the invention relates to a method for promoting the degradation of volatile chlorinated hydrocarbons. The invention aims to solve the technical problems that the existing anaerobic biological reduction method of volatile chlorinated aliphatic hydrocarbons has slow degradation speed, incomplete decomposition and easy production of toxic and harmful intermediate products. The method: 1. Preparation of culture medium; 2. Enrichment and strengthening of functional flora; 3. Configuration of anaerobic culture solution; 4. Purification and enrichment of bacteria solution; 6. The operation of the bioelectrochemical system reactor. The present invention is a biological method that uses a bioelectrochemical system to stimulate microorganisms to reduce volatile chlorinated hydrocarbons through external voltage stimulation. The degradation rate of the method in the present invention can reach more than 95% in 24 hours, and can degrade fats containing volatile chlorinated hydrocarbons. Hydrocarbon pollutants are used in environmental governance projects.

Description

A method of electrical stimulation to promote the bioreductive decomposition of volatile chlorinated hydrocarbons

technical field

The present invention relates to a method for promoting the reductive decomposition of volatile chlorinated hydrocarbons (VCHs).

technical background

Volatile chlorinated hydrocarbons (VCHs) are a class of extremely harmful and refractory organic pollutants. They are characterized by volatility, high toxicity, high density, and high solubility. They have the risk of teratogenic, carcinogenic and mutagenic. can accumulate in the environment and cause serious damage to ecosystems and human health. With the wide application of volatile chlorinated aliphatic hydrocarbons in leather, dry cleaning, pesticides and other fields, the detection rate of such pollutants in soil and groundwater is extremely high. At present, many types of VCHs are listed by China and the US Environmental Protection Agency as Prioritize the blacklist of pollutants.

In 2012, Xu Shuyuan's master's thesis "Experimental Research on the Removal of Volatile Chlorinated Hydrocarbons in Water/Soil by Loading Nano-Zerovalent Iron on Different Materials" disclosed a method of removing volatile chlorinated hydrocarbons (VCHs) by loading nano-iron on inorganic modified soil. Method, when the result table, in the aqueous solution, the removal efficiency of volatile chlorinated hydrocarbons (VCHs) is the highest to inorganic modified soil loading nano-iron, can be the trichlorethylene (TCE) and the trichlorethylene (TCE) of 10mg/L in 6 hours. 1,2-Dichloroethane (1,2-DCA) degraded 76.27% and 44.38%. However, this method is difficult to completely degrade chlorinated hydrocarbons, and its application is easily limited by the complex preparation process of nano-iron, high cost, and the easy formation of iron oxide during the reduction process, which makes the reaction difficult to continue. Microbial decomposition methods, such as microbial anaerobic reduction dechlorination process, use the microbial self-respiration metabolism to degrade chlorinated hydrocarbons, which are low in cost and environmentally friendly. However, due to the slow metabolic rate of anaerobic microorganisms (reductive dechlorination bacteria), the decomposition rate of chlorinated hydrocarbons Low, incomplete decomposition, and easy to produce toxic and harmful intermediate products, thus greatly limiting the application of biological reduction in the field of engineering.

Contents of the invention

The present invention aims to solve the technical problems of the existing anaerobic biological reduction method of volatile chlorinated aliphatic hydrocarbons, such as slow degradation speed, incomplete decomposition, and easy production of toxic and harmful intermediate products, and provides an electric stimulation to promote the anaerobic reduction of volatile chlorinated aliphatic hydrocarbons. The method of oxygen bioreductive decomposition.

A kind of electric stimulation of the present invention promotes the method for bioreductive decomposition of volatile chlorinated hydrocarbons to carry out according to the following steps:

1. Preparation of culture medium: add 50mL of distilled water to 10-15mL of activated sludge, add distilled water and activated sludge into a glass bottle, blow nitrogen for 15-20 minutes, and then seal it to maintain anaerobic conditions in the bottle and obtain culture base;

2. Enrichment and strengthening of functional flora: Add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons to the medium, place the medium in a constant temperature incubator at 30°C, and measure volatile chlorine every 3 to 5 days Degradation of substituted aliphatic hydrocarbons; when the content of volatile chlorinated aliphatic hydrocarbons drops below 50% of the initial concentration, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons again, the addition amount of sodium acetate solution and volatile chlorinated aliphatic hydrocarbons Same as the first addition amount, when the volatile chlorinated aliphatic hydrocarbon content drops below 50% of the initial concentration again, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbon again, the addition amount is the same as the first addition amount Similarly, when the volatile chlorinated aliphatic hydrocarbons drop below 20% of the initial added amount, the enrichment and strengthening of the functional flora is completed, and the enriched bacterial liquid is obtained;

3. Configure anaerobic culture medium;

4. Purification and enrichment of bacterial liquid: add the anaerobic culture liquid obtained in step 3 into a glass bottle, expose to nitrogen for 15-20 minutes, seal it, and then sterilize it in a sterilizing pot with a temperature of 120-125°C and a pressure of 100kPa-110kPa 30-40 minutes to obtain anaerobic medium; inoculate the enriched bacterial solution obtained in step 2 into the anaerobic medium, and then add volatile chlorinated aliphatic hydrocarbons; place the anaerobic medium in a constant temperature incubator at 30-32°C During the process, the degradation of volatile chlorinated aliphatic hydrocarbons was measured every 1 to 2 days. When the volatile chlorinated aliphatic hydrocarbons fell below 50% of the initial amount, volatile chlorinated aliphatic hydrocarbons were added again, and volatile chlorinated aliphatic hydrocarbons were added repeatedly according to this rule. After 2-3 times of neutral chlorinated aliphatic hydrocarbons, the first-generation medium was obtained; after the first-generation medium was transferred for 5-6 generations, the purified enriched bacterial liquid was obtained;

5. Construction and start-up of the bioelectrochemical system reactor: the bioelectrochemical system reactor consists of an anode chamber (1), a cathode chamber (2), a cation exchange membrane (3), two carbon brush electrodes (4) and a saturated Calomel electrode (5), in which the anode chamber (1) and the cathode chamber (2) are separated by a cation exchange membrane (3), and two carbon brush electrodes (4) are respectively placed in the anode chamber (1) and the cathode chamber (2) ), and communicated with the external circuit, the saturated calomel electrode (5) is inserted in the cathode chamber (2); 100-120mM potassium ferrocyanide solution is added into the anode chamber, nitrogen is exposed for 15-20 minutes, according to the purified The volume ratio of the enriched bacteria solution to the anaerobic culture solution is 1: (20-40) Add the anaerobic culture solution prepared in step 3 and the purified enriched bacteria solution obtained in step 4 into the cathode chamber (2), and Add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons into the cathode chamber (2), apply voltage to the cathode and anode poles through a DC power supply, and when it is detected that the concentration of volatile chlorinated aliphatic hydrocarbons drops below 20% of the initial amount added, Repeat the operation of adding sodium acetate solution and volatile chlorinated aliphatic hydrocarbons to the cathode chamber for 5 to 6 times to obtain a successfully started bioelectrochemical reactor system with volatile chlorinated aliphatic hydrocarbons reducing ability;

6. Operation of the bioelectrochemical system reactor: Add sodium acetate solution and pollutants containing volatile chlorinated aliphatic hydrocarbons into the cathode chamber of the successfully started bioelectrochemical reactor in step 5, and supply the positive and negative electrodes to the negative and positive electrodes through a DC power supply. Voltage is applied, and after 15 to 25 hours, the biological reduction and decomposition of volatile chlorinated hydrocarbons are completed.

The present invention is a biological method that utilizes a bioelectrochemical system (BES) to stimulate microorganisms to reduce volatile chlorinated hydrocarbons through external voltage stimulation. Volatile chlorinated hydrocarbons include tetrachlorethylene (PCE), trichlorethylene (TCE) and 1,2-Dichloroethane (1,2-DCA). Based on the biological reduction method, the present invention provides additional reducing power for microorganisms by inputting a small external electric field, and stimulates the extracellular electron transfer efficiency of microorganisms to achieve the purpose of strengthening the reduction of volatile halogenated aliphatic hydrocarbons by microorganisms. The present invention adopts the anaerobic reduction dechlorination bacteria group-cathode catalytic system to promote the reduction and decomposition of volatile chlorinated aliphatic hydrocarbons, and the completion of the bioelectrochemical cathode by an external electric field to promote the reduction and decomposition of volatile chlorinated aliphatic hydrocarbons requires two processes: (1) ) microbial cultivation and acclimatization; (2) external electric field stimulation. Quantitative and qualitative analysis of the degradation efficiency and decomposition products of volatile chlorinated aliphatic hydrocarbons promoted by biocathode, to achieve efficient reductive dechlorination of 1,2-DCA, TCE and PCE, and improve product recovery. The degradation rate of the method adopted in the invention can reach more than 95% within 24 hours. Compared with traditional physical, chemical and biological treatment methods, it has the characteristics of high degradation efficiency, low energy consumption, harmlessness and no secondary pollution. A method is provided to solve the pollution problem of volatile chlorinated aliphatic hydrocarbons in the environment.

Description of drawings

Fig. 1 specific embodiment one described bioelectrochemical system reactor structure diagram; Wherein 1 is anode chamber, 2 is cathode chamber, 3 is cation exchange membrane, 4 is carbon brush, 5 is saturated calomel electrode, 6 is resistance .

Fig. 2 is the relationship curve of the concentration of volatile chlorinated hydrocarbon pollutants with time in Test 1.

Detailed ways

Embodiment 1: A method of electrical stimulation to promote the biological reduction and decomposition of volatile chlorinated hydrocarbons in this embodiment is carried out according to the following steps:

1. Preparation of culture medium: add 50mL of distilled water to 10-15mL of activated sludge, add distilled water and activated sludge into a glass bottle, blow nitrogen for 15-20 minutes, and then seal it to maintain anaerobic conditions in the bottle and obtain culture base;

2. Enrichment and strengthening of functional flora: Add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons to the medium, place the medium in a constant temperature incubator at 30°C, and measure volatile chlorine every 3 to 5 days Degradation of substituted aliphatic hydrocarbons; when the content of volatile chlorinated aliphatic hydrocarbons drops below 50% of the initial concentration, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons again, the addition amount of sodium acetate solution and volatile chlorinated aliphatic hydrocarbons Same as the first addition amount, when the volatile chlorinated aliphatic hydrocarbon content drops below 50% of the initial concentration again, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbon again, the addition amount is the same as the first addition amount Similarly, when the volatile chlorinated aliphatic hydrocarbons drop below 20% of the initial added amount, the enrichment and strengthening of the functional flora is completed, and the enriched bacterial liquid is obtained;

3. Configure anaerobic culture medium;

4. Purification and enrichment of bacterial liquid: add the anaerobic culture liquid obtained in step 3 into a glass bottle, expose to nitrogen for 15-20 minutes, seal it, and then sterilize it in a sterilizing pot with a temperature of 120-125°C and a pressure of 100kPa-110kPa 30-40 minutes to obtain anaerobic medium; inoculate the enriched bacterial solution obtained in step 2 into the anaerobic medium, and then add volatile chlorinated aliphatic hydrocarbons; place the anaerobic medium in a constant temperature incubator at 30-32°C During the process, the degradation of volatile chlorinated aliphatic hydrocarbons was measured every 1 to 2 days. When the volatile chlorinated aliphatic hydrocarbons fell below 50% of the initial amount, volatile chlorinated aliphatic hydrocarbons were added again, and volatile chlorinated aliphatic hydrocarbons were added repeatedly according to this rule. After 2-3 times of neutral chlorinated aliphatic hydrocarbons, the first-generation medium was obtained; after the first-generation medium was transferred for 5-6 generations, the purified enriched bacterial liquid was obtained;

5. Construction and start-up of the bioelectrochemical system reactor: the bioelectrochemical system reactor consists of an anode chamber 1, a cathode chamber 2, a cation exchange membrane 3, two carbon brush electrodes 4 and a saturated calomel electrode 5, wherein the anode Chamber 1 and cathode chamber 2 are separated by cation exchange membrane 3, two carbon brush electrodes 4 are placed in anode chamber 1 and cathode chamber 2 respectively, and communicated with the external circuit, saturated calomel electrode 5 is inserted into cathode chamber 2; ～120mM potassium ferrocyanide solution was added into the anode chamber, exposed to nitrogen for 15～20 minutes, according to the volume ratio of the purified enriched bacteria solution and the anaerobic culture solution was 1: (20～40) the anaerobic solution prepared in step 3 Add the oxygen culture solution and the purified enriched bacteria solution obtained in step 4 into the cathode chamber 2, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons to the cathode chamber 2 at the same time, apply voltage to the cathode and anode through a DC power supply, When it is detected that the concentration of volatile chlorinated aliphatic hydrocarbons drops below 20% of the initial amount added, repeat the operation of adding sodium acetate solution and volatile chlorinated aliphatic hydrocarbons to the cathode chamber for 5 to 6 times, and obtain a successful start-up with volatile Bioelectrochemical reactor system for reducing capacity of chlorinated aliphatic hydrocarbons;

6. Operation of the bioelectrochemical system reactor: Add sodium acetate solution and pollutants containing volatile chlorinated aliphatic hydrocarbons into the cathode chamber of the successfully started bioelectrochemical reactor in step 5, and supply the positive and negative electrodes to the negative and positive electrodes through a DC power supply. Voltage is applied, and after 15 to 25 hours, the biological reduction and decomposition of volatile chlorinated hydrocarbons are completed.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the volatile chlorinated aliphatic hydrocarbon in step 2 is trichloroethylene, tetrachloroethylene or 1,2-dichloroethane; the others are the same as Embodiment 1 .

Specific embodiment three: the difference between this embodiment and specific embodiment one or two is: the composition of the anaerobic culture liquid described in step three is as follows: according to the ratio preparation that every 1000mL anaerobic culture liquid comprises the following components: 11.55gNa ₂ HPO ₄ ·12H ₂ O, 2.77g NaH ₂ PO ₄ ·2H ₂ O, 0.31g NH ₄ Cl, 0.13g KCl, 0.41g CH ₃ COONa, 0.1mL vitamin solution, 0.1mL mineral element solution and the rest distilled water ; Wherein said vitamin liquid contains 2.0mg vitamin H, 2.0mg folic acid, 10.0mg pyridoxine hydrochloride, 5.0mg thiamine, 5.0mg riboflavin, 5.0mg niacin, 5.0mg D- Calcium pantothenate, 0.1mg vitamin B12, 5.0mg p-aminobenzoic acid, 5.0mg lipoic acid and the rest of distilled water; the mineral element solution contains 1.5g nitrilotriacetic acid and _3.0g MgSO per 1000mL mineral element solution 7H ₂ O, 0.5g MnSO ₄ , H ₂ O, 1.0g NaCl, 0.1g FeSO ₄ , 7H ₂ O, 0.1g CoCl ₂ , 6H ₂ O, 0.1g CaCl ₂ , 0.1g ZnSO ₄ , 7H ₂ O, 0.01 g CuSO ₄ .5H ₂ O, 0.01g AlK(SO ₄ ) ₂ .12H ₂ O, 0.01g H ₃ BO ₃ , 0.01g Na ₂ MoO ₄ .2H ₂ O and the remainder of distilled water; others are the same as those in Embodiment 1 or Two same.

Specific embodiment four: the difference between this embodiment and specific embodiment one to three is: the concentration of sodium acetate described in step 2 is 10～12mmol/L, the concentration of volatile chlorinated aliphatic hydrocarbon is 2.0～2.2mmol /L; Others are the same as in one of the specific embodiments 1 to 3.

Embodiment 5: This embodiment differs from Embodiment 1 to Embodiment 4 in that in step 4, the enriched bacterial liquid is inoculated into the anaerobic medium for the first time, and the number of colonies in the anaerobic medium is 10 ⁷ - 10 ⁸ cells/mL was added; the others were the same as in one of the specific embodiments 1 to 4.

Specific embodiment six: what this embodiment is different from one of the specific embodiments one to five is that in step 4, volatile chlorinated aliphatic hydrocarbons are added to the anaerobic medium for the first time, and the concentration of volatile chlorinated aliphatic hydrocarbons is 2.0 ~2.2mmol/L is added; others are the same as one of the specific embodiments 1 to 5.

Specific embodiment seven: the difference between this embodiment and one of specific embodiments one to six is that in step 4, volatile chlorinated aliphatic hydrocarbons are added to the anaerobic medium for the second time, and the concentration of volatile chlorinated aliphatic hydrocarbons is 2.0-2.2mmol/L is added; the others are the same as in one of the specific embodiments 1 to 6.

Embodiment eight: what this embodiment is different from one of embodiment one to seven is that in step five, sodium acetate solution is added in the cathode chamber, and the concentration of sodium acetate is 10mmol/L to add; when adding volatile chlorinated aliphatic hydrocarbons, The concentration of the volatile chlorinated aliphatic hydrocarbons is 0.5-2.0 mmoles/L; the others are the same as in one of the specific embodiments 1 to 7.

Embodiment 9: The difference between this embodiment and Embodiment 1 to Embodiment 8 is that in step 6, the concentration of sodium acetate is 10 mmol/L; the others are the same as Embodiment 1 to Embodiment 8.

Verify beneficial effect of the present invention with following example:

Test 1: A method of electrical stimulation in this test to promote the biological reduction and decomposition of volatile chlorinated aliphatic hydrocarbons is carried out according to the following steps:

1. Preparation of culture medium: Add 50mL of distilled water and 10mL of activated sludge from urban sewage treatment plants into a 120mL medical glass bottle with a narrow mouth. After blowing nitrogen for 15 minutes, add a polytetrafluoroethylene plug and an aluminum foil cover to seal it to keep Anaerobic environment in the bottle to obtain the culture medium;

2. Enrichment and strengthening of functional flora: take three groups of parallel culture media and compile them into No. 1, No. 2 and No. 3, and add 0.3 mL of sodium acetate aqueous solution with a molar concentration of 1 mol/L to each group of culture media as electron For the donor, add 20uL 1,2-dichloroethane (1,2-DCA) to No. 1 medium, add 10uL trichlorethylene (TCE) to No. Chloroethylene (PCE), 1,2-dichloroethane, trichloroethylene and tetrachloroethylene were used as target pollutants—volatile chlorinated aliphatic hydrocarbons; the three groups of culture media were placed in a constant temperature incubator at 30°C, Measure the degradation situation of volatile chlorinated aliphatic hydrocarbon every 3 days; When volatile chlorinated aliphatic hydrocarbon content drops below 50% of initial concentration, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbon again, add-on and the first Once the addition is the same, when the volatile chlorinated aliphatic hydrocarbon content drops below 50% of initial concentration; Add sodium acetate solution and volatile chlorinated aliphatic hydrocarbon again, the addition is identical with the first addition, When the volatile chlorinated aliphatic hydrocarbons drop below 20% of the initial added amount, the enrichment and strengthening of the functional flora is completed, and the enriched bacterial liquid is obtained;

3. Prepare anaerobic culture medium: Prepare each 1000mL anaerobic culture medium with the following components: 11.55g Na ₂ HPO ₄ 12H ₂ O, 2.77g NaH ₂ PO ₄ 2H ₂ O, 0.31g NH ₄ Cl , 0.13g KCl, 0.41g CH ₃ COONa, 0.1mL vitamin solution, 0.1mL mineral element solution and the rest of distilled water; wherein the vitamin solution contains 2.0mg vitamin H, 2.0mg folic acid, 10.0mg vitamin H per 1000mL vitamin solution Pyridoxine hydrochloride, 5.0mg thiamine, 5.0mg riboflavin, 5.0mg niacin, 5.0mg D-calcium pantothenate, 0.1mg vitamin B12, 5.0mg p-aminobenzoic acid, 5.0mg lipoic acid and the rest of distilled water ; The mineral element liquid contains 1.5g nitrilotriacetic acid, 3.0g MgSO ₄ ·7H ₂ O, 0.5gMnSO ₄ ·H ₂ O, 1.0g NaCl, 0.1g FeSO ₄ ·7H ₂ per 1000mL mineral element liquid O, 0.1g CoCl ₂ 6H ₂ O, 0.1g CaCl ₂ , 0.1g ZnSO ₄ 7H ₂ O, 0.01g CuSO ₄ 5H ₂ O, 0.01g AlK(SO ₄ ) ₂ 12H ₂ O, 0.01g H3BO3 , 0.01g Na2MoO4 2H2O and the distilled water of surplus, obtain anaerobic culture fluid;

4. Purification and enrichment of bacteria liquid: add 60 mL of anaerobic culture liquid obtained in step 3 into 120 mL narrow-mouth glass bottles, fill three bottles, respectively labeled as I, II and III, seal them after nitrogen exposure for 15 minutes, and then store them at 121°C , high-temperature and high-pressure sterilizer with a pressure of 100KPa for 30 minutes to obtain anaerobic medium; inoculate 6mL of No. 1 enriched bacteria solution obtained in step 2 into No. 1 anaerobic medium, and add 20uL 1,2-dichloro Ethane (1,2-DCA); Inoculate 6mL of No. 2 enriched bacteria solution obtained in step 2 into No. Ⅱ anaerobic medium, and add 10uL trichlorethylene (TCE); The bacterial solution was inoculated into No. Ⅲ anaerobic medium, and 10uL of tetrachlorethylene (PCE) was added; No. Ⅰ, Ⅱ and Ⅲ anaerobic medium were placed in a constant temperature incubator at 30°C, and the volatile chlorine was measured every other day. When the concentration of volatile chlorinated aliphatic hydrocarbons drops below 50% of the initial amount, then add the same amount of volatile chlorinated aliphatic hydrocarbons of the same species respectively, repeat 3 times, and obtain the first generation culture medium; after the first-generation culture medium was transferred to 5-6 generations, the enriched bacterial liquid purified from 1,2-dichloroethane, the enriched bacterial liquid purified from trichlorethylene and the enriched bacterial liquid purified from tetrachloroethylene were obtained respectively. Bacteria collection solution;

5. Build and start three sets of bioelectrochemical system reactors: the bioelectrochemical system reactor consists of an anode chamber 1, a cathode chamber 2, a cation exchange membrane 3, two carbon brush electrodes 4 and a saturated calomel electrode 5, of which The anode chamber and the cathode chamber are separated by a cation exchange membrane. Two carbon brush electrodes are respectively placed in the anode chamber and the cathode chamber, and are connected to the external circuit through a 10-ohm resistor 6. The saturated calomel electrode 5 is inserted into the cathode chamber 2; a 100mmoles /L of potassium ferrocyanide solution was added into the anode chamber, and exposed to nitrogen for 15 minutes. At this time, No. ①, No. ② and No. ③ bioelectrochemical reactors were respectively built. Then the anaerobic culture solution obtained in step 3 and the purified enriched bacterial solution obtained in step 4 are inserted into the cathode chamber in a ratio of 5:2 by volume, and a voltage is applied to the cathode and anode by a DC power supply (adjust and maintain The potential of each reactor cathode relative to the standard hydrogen electrode is -0.26V), and the 10-ohm resistor connected in series in the circuit is a current sampling resistor, and the current flowing through the circuit is calculated by measuring the voltage at both ends of the resistor. Then add 0.3mL sodium acetate solution with a molar concentration of 1mol/L, 20uL 1,2-DCA, 10uL TCE and 10uL PCE to the cathode system of No. ①, No. ② and No. ③ reactors respectively. When it drops below 20% of the initial addition amount, repeat the above operation 5 times to obtain the bioelectrochemical reactor of 1,2-DCA, TCE and PCE successfully started;

6. Apply voltage to the negative and positive poles through a DC power supply, adjust the potential of each reactor cathode relative to the standard hydrogen electrode to be -0.26V as the working electrode, and add 0.3mL of sodium acetate solution with a molar concentration of 1mol/L and volatile Chlorinated aliphatic hydrocarbons, the voltage at both ends of the current sampling resistor and the cathode potential are measured by a data recorder and recorded in real time at 0h, 2h, 5h, 8h, 12h, 24h, and 28 hours. The biological reduction and decomposition of volatile chlorinated hydrocarbons, the obtained The relationship curves of the content of the three volatile chlorinated aliphatic hydrocarbons with time are shown in Figure 2. It can be seen from Fig. 2 that in the bioelectrochemical system reactor of this test, the degradation rate of the three volatile chlorinated aliphatic hydrocarbons can reach more than 95% in 24 hours. The reduction decomposition is relatively complete, and no toxic and harmful intermediate products are produced in the reaction process.

Claims (9)

1. a method for electric stimulation to promote the biological reduction and decomposition of volatile chlorinated hydrocarbons, characterized in that the method is carried out in the following steps: 1. Preparation of culture medium: add 50mL of distilled water to 10-15mL of activated sludge, add distilled water and activated sludge into a glass bottle, blow nitrogen for 15-20 minutes, and then seal it to maintain anaerobic conditions in the bottle and obtain culture base; 2. Enrichment and strengthening of functional flora: Add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons to the medium, place the medium in a constant temperature incubator at 30°C, and measure volatile chlorine every 3 to 5 days Degradation of substituted aliphatic hydrocarbons; when the content of volatile chlorinated aliphatic hydrocarbons drops below 50% of the initial concentration, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons again, the addition amount of sodium acetate solution and volatile chlorinated aliphatic hydrocarbons Same as the first addition amount, when the volatile chlorinated aliphatic hydrocarbon content drops below 50% of the initial concentration again, add sodium acetate solution and volatile chlorinated aliphatic hydrocarbon again, the addition amount is the same as the first addition amount Similarly, when the volatile chlorinated aliphatic hydrocarbons drop below 20% of the initial added amount, the enrichment and strengthening of the functional flora is completed, and the enriched bacterial liquid is obtained; 3. Configure anaerobic culture medium; 4. Purification and enrichment of bacterial liquid: add the anaerobic culture liquid obtained in step 3 into a glass bottle, expose to nitrogen for 15-20 minutes, seal it, and then sterilize it in a sterilizing pot with a temperature of 120-125°C and a pressure of 100kPa-110kPa 30-40 minutes to obtain anaerobic medium; inoculate the enriched bacterial solution obtained in step 2 into the anaerobic medium, and then add volatile chlorinated aliphatic hydrocarbons; place the anaerobic medium in a constant temperature incubator at 30-32°C During the process, the degradation of volatile chlorinated aliphatic hydrocarbons was measured every 1 to 2 days. When the volatile chlorinated aliphatic hydrocarbons fell below 50% of the initial amount, volatile chlorinated aliphatic hydrocarbons were added again, and volatile chlorinated aliphatic hydrocarbons were added repeatedly according to this rule. After 2-3 times of neutral chlorinated aliphatic hydrocarbons, the first-generation medium was obtained; after the first-generation medium was transferred for 5-6 generations, the purified enriched bacterial liquid was obtained; 5. Construction and start-up of the bioelectrochemical system reactor: the bioelectrochemical system reactor consists of an anode chamber (1), a cathode chamber (2), a cation exchange membrane (3), two carbon brush electrodes (4) and a saturated Calomel electrode (5), in which the anode chamber (1) and the cathode chamber (2) are separated by a cation exchange membrane (3), and two carbon brush electrodes (4) are respectively placed in the anode chamber (1) and the cathode chamber (2) ), and communicated with the external circuit, the saturated calomel electrode (5) is inserted in the cathode chamber (2); 100-120mM potassium ferrocyanide solution is added into the anode chamber, nitrogen is exposed for 15-20 minutes, according to the purified The volume ratio of the enriched bacteria solution to the anaerobic culture solution is 1: (20-40) Add the anaerobic culture solution prepared in step 3 and the purified enriched bacteria solution obtained in step 4 into the cathode chamber (2), and Add sodium acetate solution and volatile chlorinated aliphatic hydrocarbons into the cathode chamber (2), apply voltage to the cathode and anode poles through a DC power supply, and when it is detected that the concentration of volatile chlorinated aliphatic hydrocarbons drops below 20% of the initial amount added, Repeat the operation of adding sodium acetate solution and volatile chlorinated aliphatic hydrocarbons to the cathode chamber for 5 to 6 times to obtain a successfully started bioelectrochemical reactor system with volatile chlorinated aliphatic hydrocarbons reducing ability; Six, the operation of the bioelectrochemical system reactor: the sodium acetate solution and the pollutants containing volatile chlorinated aliphatic hydrocarbons are added to the cathode chamber (2) of the bioelectrochemical reactor successfully started in step 5, and the direct current power is supplied to the reactor. Voltage is applied to the cathode and anode, and after 15 to 25 hours, the biological reduction and decomposition of volatile chlorinated hydrocarbons is completed. 2. A kind of electric stimulation according to claim 1 promotes the method for biological reduction and decomposition of volatile chlorinated hydrocarbons, characterized in that in step 2, volatile chlorinated aliphatic hydrocarbons are trichloroethylene, tetrachloroethylene or 1,2- Dichloroethane. 3. A kind of electric stimulation according to claim 1 and 2 promotes the method for bioreductive decomposition of volatile chlorinated hydrocarbons, characterized in that the composition of the anaerobic culture solution described in step 3 is as follows: by every 1000mL anaerobic culture The solution was prepared in proportion to the following components: 11.55g Na ₂ HPO ₄ ·12H ₂ O, 2.77g NaH ₂ PO ₄ ·2H ₂ O, 0.31g NH ₄ Cl, 0.13g KCl, 0.41g CH ₃ COONa, 0.1mL vitamin solution, 0.1mL mineral element solution and the rest of distilled water; wherein the vitamin solution contains 2.0mg of vitamin H, 2.0mg of folic acid, 10.0mg of pyridoxine hydrochloride, 5.0mg of thiamine, and 5.0mg of nuclear Flavin, 5.0mg niacin, 5.0mg D-calcium pantothenate, 0.1mg vitamin B12, 5.0mg p-aminobenzoic acid, 5.0mg lipoic acid and the rest of distilled water; the mineral element liquid contains 1.5g nitrilotriacetic acid, 3.0gMgSO4 _{· 7H2O} , 0.5g _MnSO4 · _H2O , 1.0g NaCl, 0.1g FeSO4· _7H2O , 0.1g _{CoCl2 · 6H2O} , _0.1gCaCl2 , 0.1g ZnSO ₄ 7H ₂ O, 0.01g CuSO ₄ 5H ₂ O, 0.01g AlK(SO ₄ ) ₂ 12H ₂ O, 0.01g H ₃ BO ₃ , 0.01g Na ₂ MoO ₄ 2H ₂ O and remaining distilled water. 4. according to claim 1 or 2 described a kind of method that electrical stimulation promotes the biological reduction decomposition of volatile chlorinated hydrocarbons, it is characterized in that the concentration of sodium acetate described in step 2 is 10～12mmol/L, volatile chlorine The concentration of substituting aliphatic hydrocarbons is 2.0-2.2mmol/L. 5. A kind of electrical stimulation according to claim 1 and 2 promotes the method for bioreductive decomposition of volatile chlorinated hydrocarbons, it is characterized in that in step 4, the enriched bacteria liquid is inoculated into the anaerobic medium for the first time, press The number of colonies in the anaerobic medium is 10 ⁷ -10 ⁸ cells/mL. 6. A kind of electrical stimulation according to claim 1 and 2 promotes the method for bioreductive decomposition of volatile chlorinated hydrocarbons, characterized in that in step 4, volatile chlorinated aliphatic hydrocarbons are added to the anaerobic medium for the first time, Add according to the concentration of volatile chlorinated aliphatic hydrocarbons at 2.0-2.2mmol/L. 7. A kind of electrical stimulation according to claim 1 and 2 promotes the method for bioreductive decomposition of volatile chlorinated hydrocarbons, characterized in that in step 4, adding volatile chlorinated aliphatic hydrocarbons to the anaerobic medium for the second time , according to the concentration of volatile chlorinated aliphatic hydrocarbons is 2.0 ~ 2.2mmol/L to add. 8. A kind of electrical stimulation according to claim 1 and 2 promotes the method for biological reduction and decomposition of volatile chlorinated hydrocarbons, characterized in that in step 5, sodium acetate solution is added to the cathode chamber, and the concentration of sodium acetate is 10mmol/L Add; add volatile chlorinated aliphatic hydrocarbons, and add according to the concentration of volatile chlorinated aliphatic hydrocarbons at 0.5-2.0mmol/L. 9. A method for electrical stimulation to promote biological reduction and decomposition of volatile chlorinated hydrocarbons according to claim 1 or 2, characterized in that in step 6, the concentration of sodium acetate is 10mmol/L.