Low-concentration PCB copper-containing wastewater treatment method based on anaerobic condition

Abstract

The invention relates to the technical field of sewage treatment, and particularly discloses a low-concentration PCB copper-containing wastewater treatment method based on anaerobic conditions. Comprising the following steps: step 1), inoculating a nutrient solution with clostridium thermocellum, ethanol thermal anaerobic bacillus and rhodopseudomonas palustris, and performing anaerobic culture to obtain a wastewater treatment bacterial solution; the method comprises the following steps of (1) adding a wastewater treatment bacterial solution into a container, (2) injecting copper-containing wastewater into the container, adding the wastewater treatment bacterial solution, and carrying out anaerobic treatment for 7-10 days to obtain pretreated wastewater, and (3) filtering and degerming the pretreated wastewater to obtain pre-copper-removed wastewater. The method has the advantages that the cost of a PCB wastewater copper removal process is reduced, and the economic value is relatively high.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment, and in particular to a method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions. Background Art

[0002] PCB, also known as printed circuit board, is made by electronic printing technology, and its main function is to provide electrical connections between various parts on the circuit board. Since the manufacture of circuit boards is a very complex and comprehensive processing technology, a variety of chemical materials of different properties are used in the production process, resulting in complex components of discharged production wastewater and difficulty in treatment. Copper is one of the most common heavy metal pollutants in printed circuit board wastewater.

[0003] Since the concentration of copper pollutants in PCB wastewater is high, it causes serious environmental pollution and the emission standards are constantly improving. Therefore, the treatment of copper in PCB wastewater is of great significance in environmental protection.

[0004] Currently, the conventional methods for processing copper are mainly chemical and physicochemical methods, but the large-scale use of chemical agents will lead to high costs, so there is still room for improvement. Summary of the invention

[0005] In order to reduce the cost of PCB wastewater copper removal process, the present application provides a low-concentration PCB copper-containing wastewater treatment method based on anaerobic conditions.

[0006] The present application provides a method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, which adopts the following technical solution: A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions comprises the following steps: Step 1), inoculating Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris into a nutrient solution, and culturing anaerobically to obtain a wastewater treatment bacterial solution; Step 2), injecting copper-containing wastewater into a container, adding wastewater treatment bacterial solution, and anaerobically treating for 7-10 days to obtain pretreated wastewater; step 3), filtering and sterilizing the pretreated wastewater to obtain pre-copper-removed wastewater.

[0007] By adopting the above technical scheme, the wastewater is anaerobically treated by using a wastewater treatment bacterial liquid cultivated with Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris, so that the copper in the wastewater can be well removed, and because of the cooperation of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris, they can have higher activity in copper-containing wastewater, thereby exerting a better sewage treatment effect, overcoming the problem of low activity of general bacteria in copper-containing wastewater, and reducing the copper content in the wastewater to a lower level through biological treatment, without the need to add a large amount of additional chemicals for sewage treatment, and without the need to introduce a large amount of gas to maintain the growth of microorganisms, which can greatly save costs and has high economic value.

[0008] Preferably, in step 1), the nutrient solution is a compound of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract.

[0009] By adopting the above technical scheme, by specifically selecting the nutrient solution as a compound of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract, under the action of snail mucus extract and oyster meat extract, the microorganisms in the wastewater treatment bacterial liquid cultured have higher activity in copper-containing wastewater, can better play the role of removing copper in wastewater, so that the sewage treatment effect is better and has higher economic value.

[0010] Preferably, in the nutrient solution, the mass ratio of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract is 1000:4-6:3-5:6-8:8-10:5-7.

[0011] By adopting the above technical scheme, by specifically selecting the mass ratio of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract, the activity of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris can be improved, which can achieve a better effect of removing copper from sewage.

[0012] Preferably, in the step 1), the mass ratio of Clostridium thermocellum, thermoanaerobic bacillus ethanol, and Rhodopseudomonas palustris is 0.04-0.06: 0.02-0.04: 0.07-0.09.

[0013] By adopting the above technical scheme and specifically selecting the mass ratio of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria and Rhodopseudomonas palustris, Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria and Rhodopseudomonas palustris can reproduce faster during the cultivation process and have higher economic value.

[0014] Preferably, in the step 1), the mass ratio of Clostridium thermocellum, thermoanaerobic bacillus ethanol, Rhodopseudomonas palustris, and nutrient solution is 0.04-0.06: 0.02-0.04: 0.07-0.09: 1026-1036.

[0015] By adopting the above technical scheme, by specifically selecting the mass ratio of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, Rhodopseudomonas palustris and nutrient solution, the effect of culturing Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria and Rhodopseudomonas palustris is better, the activity of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria and Rhodopseudomonas palustris is better improved, the reproduction speed is faster, and the wastewater treatment bacterial liquid prepared can achieve a better effect of removing copper from sewage.

[0016] Preferably, in step 1), the culture temperature during anaerobic culture is 32-34°C.

[0017] By adopting the above technical solution and specifically selecting the culture temperature to be 32-34°C, it is more conducive to improving the activity of each bacteria, thereby producing the wastewater treatment bacterial liquid more quickly.

[0018] Preferably, in step 1), the culture is performed anaerobically until OD600 is ≥1.

[0019] By adopting the above technical solution, by specifically selecting and culturing to OD600 ≥ 1, the bacterial concentration in the wastewater treatment bacterial liquid is sufficient, and it can reproduce rapidly in the sewage better, thereby achieving a better effect of removing copper from the sewage.

[0020] Preferably, in step 2), the mass ratio of copper-containing wastewater to wastewater treatment bacterial liquid is 10000:1-2.

[0021] By adopting the above technical scheme and specifically selecting the mass ratio of copper-containing wastewater and wastewater treatment bacterial liquid, the skill can achieve a better effect of removing copper from sewage, and can also well control costs, thus having higher economic value.

[0022] Preferably, in step 2), the temperature is kept at 32-34° C. during anaerobic treatment.

[0023] By adopting the above technical solution and specifically selecting a constant temperature of 32-34°C, the activity of various bacteria in the sewage treatment process is higher and the sewage treatment effect is better.

[0024] In summary, this application has the following beneficial effects: 1. Since the present application uses a wastewater treatment bacterial liquid cultivated from Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris to perform anaerobically treatment on wastewater, copper in wastewater can be removed well. Moreover, due to the cooperation of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris, they can have high activity in copper-containing wastewater, thereby achieving a good sewage treatment effect, overcoming the problem of low activity of general bacteria in copper-containing wastewater. The copper content in wastewater can be reduced to a low level through biological treatment, without the need to add a large amount of chemicals for sewage treatment, and without the need to introduce a large amount of gas to maintain microbial growth, which can greatly save costs and has high economic value.

[0025] 2. In the present application, it is preferred to specifically select the nutrient solution as a compound of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract. Under the action of snail mucus extract and oyster meat extract, the microorganisms in the wastewater treatment bacterial liquid obtained by culture are more active in copper-containing wastewater, and can better play the role of removing copper from wastewater, so that the sewage treatment effect is better and has higher economic value.

[0026] 3. In the present application, it is preferred to specifically select the mass ratio of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract to improve the activity of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris, which can achieve a better effect of removing copper from sewage.

[0027] 4. In the present application, it is preferred to specifically select the mass ratio of Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris so that Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris reproduce faster during the culture process and have higher economic value. DETAILED DESCRIPTION

[0028] The present application is further described in detail below with reference to the embodiments.

[0029] Example 1 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions comprises the following steps: Step 1), 10 kg of deionized water, 40 g of sodium chloride, 30 g of peptone, 60 g of beef extract, 80 g of snail mucus extract, and 50 g of oyster meat extract are mixed evenly to prepare a nutrient solution, and then 0.4 g of Clostridium thermocellum, 0.2 g of ethanol thermoanaerobic rod-shaped bacteria, and 0.7 g of Rhodopseudomonas palustris are inoculated into the nutrient solution, kept at a constant temperature of 32°C, and anaerobically cultured until OD600 ≥ 1 to obtain a wastewater treatment bacterial solution.

[0030] Step 2), inject the copper-containing wastewater into a container, add wastewater treatment bacterial solution, inject 1 kg of wastewater treatment bacterial solution for every 10,000 kg of copper-containing wastewater, keep the temperature at 32-34° C., and perform anaerobic treatment for 7-10 days to obtain pretreated wastewater.

[0031] Step 3), the pre-treated wastewater is filtered through a 2000 mesh filter cloth to remove the precipitate, and then filtered through a 22 μm filter membrane for sterilization to obtain pre-copper-removed wastewater.

[0032] Clostridium thermocellum was purchased from Beijing Biobio Biotechnology Co., Ltd., platform number: Bio-72834.

[0033] Ethanol thermoanaerobic bacillus was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd., platform number: Bio-117711.

[0034] Rhodopseudomonas palustris was purchased from Beijing Biobio Biotech Co., Ltd., platform number: Bio-78385.

[0035] Deionized water was commercially available with CAS number: 7732-18-5.

[0036] Sodium chloride was commercially available, CAS number: 7647-14-5.

[0037] Peptone was commercially available, CAS number: 73049-73-7.

[0038] Beef extract was commercially available, CAS number: 68990-09-0.

[0039] The snail mucus extract was purchased from Shaanxi Mufan Biotechnology Co., Ltd., a water-soluble extract with an extraction ratio of 10:1.

[0040] Oyster meat extract was purchased from Shaanxi Tianxingjian Biochemical Technology Co., Ltd., a water-soluble extract with an extraction ratio of 10:1.

[0041] Example 2 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions comprises the following steps: Step 1), 10kg of deionized water, 50g of sodium chloride, 40g of peptone, 70g of beef extract, 90g of snail mucus extract, and 60g of oyster meat extract are mixed evenly to prepare a nutrient solution, and then 0.5g of Clostridium thermocellum, 0.3g of ethanol thermoanaerobic rod-shaped bacteria, and 0.8g of Rhodopseudomonas palustris are inoculated into the nutrient solution, kept at a constant temperature of 33°C, and anaerobically cultured until OD600≥1 to obtain a wastewater treatment bacterial solution.

[0042] Step 2), inject the copper-containing wastewater into a container, add wastewater treatment bacterial solution, inject 1.5 kg of wastewater treatment bacterial solution for every 10,000 kg of copper-containing wastewater, keep the temperature at 32-34°C, and perform anaerobic treatment for 7-10 days to obtain pretreated wastewater.

[0043] Step 3), the pre-treated wastewater is filtered through a 2000 mesh filter cloth to remove the precipitate, and then filtered through a 22 μm filter membrane for sterilization to obtain pre-copper-removed wastewater.

[0044] Clostridium thermocellum was purchased from Beijing Biobio Biotechnology Co., Ltd., platform number: Bio-72834.

[0045] Ethanol thermoanaerobic bacillus was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd., platform number: Bio-117711.

[0046] Rhodopseudomonas palustris was purchased from Beijing Biobio Biotech Co., Ltd., platform number: Bio-78385.

[0047] Deionized water was commercially available, CAS number: 7732-18-5.

[0048] Sodium chloride was commercially available, CAS number: 7647-14-5.

[0049] Peptone was commercially available with CAS number: 73049-73-7.

[0050] Beef extract was commercially available, CAS number: 68990-09-0.

[0051] The snail mucus extract was purchased from Shaanxi Mufan Biotechnology Co., Ltd., a water-soluble extract with an extraction ratio of 10:1.

[0052] Oyster meat extract was purchased from Shaanxi Tianxingjian Biochemical Technology Co., Ltd., a water-soluble extract with an extraction ratio of 10:1.

[0053] Example 3 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions comprises the following steps: Step 1), 10 kg of deionized water, 60 g of sodium chloride, 50 g of peptone, 80 g of beef extract, 100 g of snail mucus extract, and 70 g of oyster meat extract are mixed evenly to prepare a nutrient solution, and then 0.6 g of Clostridium thermocellum, 0.4 g of ethanol thermoanaerobic rod-shaped bacteria, and 0.9 g of Rhodopseudomonas palustris are inoculated into the nutrient solution, kept at a constant temperature of 34° C., and anaerobically cultured until OD600 ≥ 1 to obtain a wastewater treatment bacterial solution.

[0054] Step 2), inject the copper-containing wastewater into a container, add wastewater treatment bacterial solution, inject 2kg of wastewater treatment bacterial solution for every 10,000kg of copper-containing wastewater, keep the temperature at 32-34°C, and perform anaerobic treatment for 7-10 days to obtain pretreated wastewater.

[0055] Step 3), the pre-treated wastewater is filtered through a 2000 mesh filter cloth to remove the precipitate, and then filtered through a 22 μm filter membrane for sterilization to obtain pre-copper-removed wastewater.

[0056] Clostridium thermocellum was purchased from Beijing Biobio Biotechnology Co., Ltd., platform number: Bio-72834.

[0057] Ethanol thermoanaerobic bacillus was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd., platform number: Bio-117711.

[0058] Rhodopseudomonas palustris was purchased from Beijing Biobio Biotech Co., Ltd., platform number: Bio-78385.

[0059] Deionized water was commercially available, CAS number: 7732-18-5.

[0060] Sodium chloride was commercially available, CAS number: 7647-14-5.

[0061] Peptone was commercially available with CAS number: 73049-73-7.

[0062] Beef extract was commercially available, CAS number: 68990-09-0.

[0063] The snail mucus extract was purchased from Shaanxi Mufan Biotechnology Co., Ltd., a water-soluble extract with an extraction ratio of 10:1.

[0064] Oyster meat extract was purchased from Shaanxi Tianxingjian Biochemical Technology Co., Ltd., a water-soluble extract with an extraction ratio of 10:1.

[0065] Comparative Example 1 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, compared with Example 2, the only difference is: Bacillus parabrevis was used to replace Clostridium thermocellum in equal amounts.

[0066] Bacillus parabrevis was purchased from Beijing Biobio Biotechnology Co., Ltd., platform number: Bio-049015.

[0067] Comparative Example 2 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, compared with Example 2, the only difference is: Escherichia coli was used to replace the ethanol thermoanaerobic bacillus in an equal amount.

[0068] Escherichia coli was purchased from Beijing Biobio Biotechnology Co., Ltd., platform number: Bio-60495.

[0069] Comparative Example 3 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, compared with Example 2, the only difference is: Corynebacterium heatherum was used to replace Rhodopseudomonas palustris in equal amounts.

[0070] Corynebacterium heatherum was purchased from Beijing Biobio Biotech Co., Ltd., platform number: Bio-62136.

[0071] Comparative Example 4 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, compared with Example 2, the only difference is: Bacillus parabrevis was used to replace Clostridium thermocellum in equal amounts, Escherichia coli was used to replace Thermoanaerobic Bacillus ethanolii in equal amounts, and Corynebacterium heatherum was used to replace Rhodopseudomonas palustris in equal amounts.

[0072] Bacillus parabrevis was purchased from Beijing Biobio Biotechnology Co., Ltd., platform number: Bio-049015.

[0073] Escherichia coli was purchased from Beijing Biobio Biotechnology Co., Ltd., platform number: Bio-60495.

[0074] Corynebacterium heatherum was purchased from Beijing Biobio Biotech Co., Ltd., platform number: Bio-62136.

[0075] Comparative Example 5 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, compared with Example 2, the only difference is: The snail mucus extract was replaced with an equal amount of yeast extract.

[0076] Yeast extract was purchased from Hebei Hongtao Bioengineering Co., Ltd.

[0077] Comparative Example 6 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, compared with Example 2, the only difference is: An equal amount of glucose was used to replace the oyster meat extract.

[0078] Glucose was purchased from Zhengzhou Yuhe Food Additive Co., Ltd.

[0079] Comparative Example 7 A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, compared with Example 2, the only difference is: The snail mucus extract was replaced by an equal amount of yeast extract, and the oyster meat extract was replaced by an equal amount of glucose.

[0080] Yeast extract was purchased from Hebei Hongtao Bioengineering Co., Ltd.

[0081] Glucose was purchased from Zhengzhou Yuhe Food Additive Co., Ltd.

[0082] Experiment 1 The same batch of sewage was treated by the low-concentration PCB copper-containing wastewater treatment method based on anaerobic conditions in each embodiment and comparative example, and the copper ion content in the treated sewage was detected.

[0083] The wastewater used for the experiment was randomly sampled ten times to detect the copper ion content of the wastewater before being treated with the low-concentration PCB copper-containing wastewater treatment method based on anaerobic conditions. The test results were averaged. The copper ion content of the wastewater used in this experiment was specifically: 1.543 mg / L.

[0084] Copper ion content detection method: atomic absorption spectrometry.

[0085] The specific test data of Experiment 1 are shown in Table 1.

[0086] Table 1 Copper ion content of purified water (mg / L) Example 1 0.072 Example 2 0.053 Example 3 0.061 Comparative Example 1 0.683 Comparative Example 2 0.761 Comparative Example 3 0.573 Comparative Example 4 0.895 Comparative Example 5 0.222 Comparative Example 6 0.185 Comparative Example 7 0.257 According to the data comparison of each embodiment and comparative example in Table 1, it can be obtained that the copper ion content in the sewage after purification in each embodiment is significantly lower than that in each comparative example. Among them, although comparative examples 1-4 can reduce the copper ion content, the copper ion content in the sewage finally discharged is greater than 0.5 mg / L, which is still at a pollution level and fails to meet the purification standard requirements. Chemical components need to be added in the later treatment steps to further reduce the copper ion content, resulting in a high sewage treatment cost. Although comparative examples 5-7 can make the copper ion content in the sewage meet the purification standard, the copper ion content is higher than that of each embodiment.

[0087] It can be seen that in Comparative Examples 1-4, the thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris of the embodiments are replaced solely or completely by other bacterial species for sewage treatment, resulting in a significant decrease in the effect of reducing the copper ion content. This proves that when Clostridium thermocellum, ethanol thermoanaerobic rod-shaped bacteria, and Rhodopseudomonas palustris are compounded, the activity of each bacteria in copper ion-contaminated wastewater can be significantly improved, and the copper ion content in the sewage can be quickly reduced. In the subsequent treatment steps, there is no need to add chemical drugs for copper ion removal, which effectively reduces costs and has higher economic value.

[0088] In addition, in Comparative Examples 5-7, other nutrients were used to replace the snail mucus extract and oyster meat extract in the examples alone or in whole, resulting in a decrease in the activity of each bacteria. Therefore, under the same sewage treatment time, the degree of copper ion removal was reduced, resulting in sewage treatment effects that were inferior to those of the examples.

[0089] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions, characterized in that: The following steps are involved: Step 1), inoculating Clostridium thermocellum, ethanol thermoanaerobic bacillus, and Rhodopseudomonas palustris into a nutrient solution, and culturing anaerobically to obtain a wastewater treatment bacterial solution; Step 2), injecting the copper-containing wastewater into a container, adding wastewater treatment bacterial solution, and anaerobically treating for 7-10 days to obtain pretreated wastewater; Step 3), filtering and sterilizing the pretreated wastewater to obtain pre-copper-removed wastewater.

2. A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions according to claim 1, characterized in that: In the step 1), the nutrient solution is a compound of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract.

3. A method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions according to claim 2, characterized in that: In the nutrient solution, the mass ratio of deionized water, sodium chloride, peptone, beef extract, snail mucus extract and oyster meat extract is 1000:4-6:3-5:6-8:8-10:5-7.

4. The method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions according to claim 3, characterized in that: In the step 1), the mass ratio of Clostridium thermocellum, thermoanaerobic bacillus ethanol, and Rhodopseudomonas palustris is 0.04-0.06: 0.02-0.04: 0.07-0.

09.

5. The method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions according to claim 4, characterized in that: In the step 1), the mass ratio of Clostridium thermocellum, ethanol thermoanaerobic bacillus, Rhodopseudomonas palustris, and nutrient solution is 0.04-0.06: 0.02-0.04: 0.07-0.09: 1026-1036.

6. The method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions according to claim 1, characterized in that: In the step 1), the culture temperature during anaerobic culture is 32-34°C.

7. The method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions according to claim 6, characterized in that: In the step 1), the culture is performed anaerobically until OD600 is ≥1.

8. The method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions according to claim 5, characterized in that: In the step 2), the mass ratio of the copper-containing wastewater to the wastewater treatment bacterial solution is 10000:1-2.

9. The method for treating low-concentration PCB copper-containing wastewater based on anaerobic conditions according to claim 8, characterized in that: In the step 2), the temperature is kept at 32-34° C. during anaerobic treatment.