A treatment method for low-concentration PCB copper-containing wastewater based on anaerobic conditions

Abstract

The present invention relates to the technical field of sewage treatment, and specifically discloses a method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions. The method includes the following steps: Step 1), inoculating Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris into a nutrient solution and performing anaerobic culture to obtain a wastewater treatment bacterial solution; Step 2), injecting the copper-containing wastewater into a container, adding the wastewater treatment bacterial solution, and performing anaerobic treatment for 7-10 days to obtain pretreated wastewater; Step 3), filtering and sterilizing the pretreated wastewater to obtain pre-copper-removed wastewater. The present invention has the advantages of reducing the cost of the copper removal process for PCB wastewater and having relatively high economic value.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and particularly to a method for treating low-concentration PCB copper-containing wastewater under 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 components on the circuit board. Since manufacturing circuit boards is a very complex comprehensive processing technology, various chemical materials with different properties are used in the production process, resulting in complex components of the discharged production wastewater and difficult treatment. Copper is one of the most common heavy metal pollutants in printed circuit board wastewater.

[0003] Due to the high concentration of copper pollutants in PCB wastewater, which causes serious environmental pollution and continuously increasing discharge standards, treating copper in PCB wastewater is of great significance in environmental protection.

[0004] Currently, the conventional methods for treating copper are mainly chemical methods and physical and chemical methods. However, the large amount of chemical agents used will lead to high costs. Therefore, there is still room for improvement. Summary of the Invention

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

[0006] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions provided by the present application adopts the following technical solutions:

[0007] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions includes the following steps:

[0008] Step 1), inoculate Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris into a nutrient solution and perform anaerobic culture to obtain a wastewater treatment bacterial solution;

[0009] Step 2), inject the copper-containing wastewater into a container, add the wastewater treatment bacterial solution, and perform anaerobic treatment for 7 - 10 days to obtain pretreated wastewater; Step 3), filter and sterilize the pretreated wastewater to obtain pre-copper-removed wastewater.

[0010] By adopting the above technical solution, anaerobic treatment of wastewater is carried out using the wastewater treatment bacterial liquid cultured from Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris. It can effectively remove copper in the wastewater. Moreover, due to the cooperation of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris, it has high activity in copper-containing wastewater, thus achieving a better sewage treatment effect, overcoming the problem of low activity of general bacteria in copper-containing wastewater. Just through biological treatment, the copper content in the wastewater can be reduced to a relatively low level, without the need to add a large amount of additional chemical drugs for sewage treatment, nor to introduce a large amount of gas to maintain the growth of microorganisms, which can greatly save costs and has high economic value.

[0011] Preferably, 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.

[0012] By adopting the above technical solution, 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 the snail mucus extract and oyster meat extract, the microorganisms in the cultured wastewater treatment bacterial liquid have higher activity in copper-containing wastewater, can better play the role of removing copper in sewage, making the sewage treatment effect better and having higher economic value.

[0013] 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.

[0014] By adopting the above technical solution, by specifically selecting the mass ratio of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract, the effect of improving the activity of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris is better, and it can achieve a better effect of removing copper from sewage.

[0015] Preferably, in the step 1), the mass ratio of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris is 0.04 - 0.06:0.02 - 0.04:0.07 - 0.09.

[0016] By adopting the above technical solution, by specifically selecting the mass ratio of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris, the reproduction speed of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris is faster during the cultivation process, and it has higher economic value.

[0017] Preferably, in the step 1), the mass ratio of Clostridium thermocellum, Thermoanaerobacter ethanolicus, Rhodopseudomonas palustris, and nutrient solution is 0.04 - 0.06:0.02 - 0.04:0.07 - 0.09:1026 - 1036.

[0018] By adopting the above technical solution, by specifically selecting the mass ratio of Clostridium thermocellum, Thermoanaerobacter ethanolicus, Rhodopseudomonas palustris, and nutrient solution, the effect of culturing Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris is better, the activity of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris is better improved, the reproduction speed is faster, and the prepared wastewater treatment bacterial liquid can achieve a better effect of removing copper from sewage.

[0019] Preferably, in the step 1), the culture temperature during anaerobic culture is 32 - 34 °C.

[0020] By adopting the above technical solution, by specifically selecting the culture temperature of 32 - 34 °C, it is more conducive to improving the activity of each bacterium, and thus the wastewater treatment bacterial liquid can be prepared faster.

[0021] Preferably, in the step 1), anaerobic culture is carried out until OD600 ≥ 1.

[0022] By adopting the above technical solution, by specifically selecting the culture until OD600 ≥ 1, the bacterial concentration in the wastewater treatment bacterial liquid is sufficient, and it can reproduce rapidly in sewage better, so as to achieve a better effect of removing copper from sewage.

[0023] Preferably, in the step 2), the mass ratio of copper-containing wastewater to wastewater treatment bacterial liquid is 10000:1 - 2.

[0024] By adopting the above technical solution, by specifically selecting the mass ratio of copper-containing wastewater to wastewater treatment bacterial liquid, it can achieve a better effect of removing copper from sewage, and can well control the cost, with higher economic value.

[0025] Preferably, in the step 2), the temperature is kept constant at 32 - 34 °C during anaerobic treatment.

[0026] By adopting the above technical solution, by specifically selecting the constant temperature of 32 - 34 °C, the activity of each bacterium during the sewage treatment process is higher, and the sewage treatment effect is better.

[0027] In summary, the present application has the following beneficial effects:

[0028] 1. Since this application anaerobically treats wastewater by using a wastewater treatment bacterial liquid cultured from Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris, it can effectively remove copper in the wastewater. Moreover, due to the cooperation of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris, it has high activity in copper-containing wastewater, thus achieving a better sewage treatment effect, overcoming the problem of low activity of general bacteria in copper-containing wastewater. Through biological treatment alone, the copper content in the wastewater can be reduced to a relatively low level, without the need to add a large amount of additional chemical agents for sewage treatment, nor to introduce a large amount of gas to maintain the growth of microorganisms, which can greatly save costs and has high economic value.

[0029] 2. In this application, it is preferably through 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 the snail mucus extract and oyster meat extract, the microorganisms in the cultured wastewater treatment bacterial liquid have higher activity in copper-containing wastewater, can better exert the effect of removing copper in the sewage, making the sewage treatment effect better and having higher economic value.

[0030] 3. In this application, it is preferably through specifically selecting the mass ratio of deionized water, sodium chloride, peptone, beef extract, snail mucus extract, and oyster meat extract, which has a better effect of improving the activity of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris, and can achieve a better effect of removing copper from sewage.

[0031] 4. In this application, it is preferably through specifically selecting the mass ratio of Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris, so that Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris have a faster reproduction rate during the cultivation process and have higher economic value. Detailed implementation mode

[0032] The following further elaborates on this application in conjunction with examples.

[0033] Example 1

[0034] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions includes the following steps:

[0035] Step 1), Mix 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 evenly to obtain a nutrient solution. Then inoculate 0.4 g of Clostridium thermocellum, 0.2 g of Thermoanaerobacter ethanolicus, and 0.7 g of Rhodopseudomonas palustris into the nutrient solution, keep it at a constant temperature of 32 °C, and anaerobically culture until OD600 ≥ 1 to obtain a wastewater treatment bacterial liquid.

[0036] Step 2): Inject the copper-containing wastewater into a container, add the wastewater treatment bacterial liquid. For every 10,000 kg of copper-containing wastewater, 1 kg of wastewater treatment bacterial liquid is injected. Keep the temperature at 32 - 34 °C and perform anaerobic treatment for 7 - 10 days to obtain the pretreated wastewater.

[0037] Step 3): Filter the pretreated wastewater through a 2000-mesh filter cloth to remove the precipitate, and then filter it through a 22-μm filter membrane to remove bacteria to obtain the copper-pretreated wastewater.

[0038] Clostridium thermocellum was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-72834.

[0039] Thermoanaerobacter ethanolicus was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-117711.

[0040] Rhodopseudomonas palustris was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-78385.

[0041] Deionized water is commercially available, CAS number: 7732-18-5.

[0042] Sodium chloride is commercially available, CAS number: 7647-14-5.

[0043] Peptone is commercially available, CAS number: 73049-73-7.

[0044] Beef extract is commercially available, CAS number: 68990-09-0.

[0045] Snail mucus extract was purchased from Shaanxi Mufan Biotechnology Co., Ltd., water-soluble extract, extraction ratio 10:1.

[0046] Oyster meat extract was purchased from Shaanxi Tianxingjian Biochemical Technology Co., Ltd., water-soluble extract, extraction ratio 10:1.

[0047] Example 2

[0048] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, comprising the following steps:

[0049] Step 1): Mix 10 kg of deionized water, 50 g of sodium chloride, 40 g of peptone, 70 g of beef extract, 90 g of snail mucus extract, and 60 g of oyster meat extract evenly to prepare a nutrient solution. Then inoculate 0.5 g of Clostridium thermocellum, 0.3 g of Thermoanaerobacter ethanolicus, and 0.8 g of Rhodopseudomonas palustris into the nutrient solution. Keep the temperature at 33 °C and perform anaerobic culture until OD600 ≥ 1 to obtain the wastewater treatment bacterial liquid.

[0050] Step 2), Inject the copper-containing wastewater into a container, add the wastewater treatment bacterial liquid. For every 10,000 kg of copper-containing wastewater, 1.5 kg of wastewater treatment bacterial liquid is injected. Keep the temperature at 32 - 34 °C and perform anaerobic treatment for 7 - 10 days to obtain the pretreated wastewater.

[0051] Step 3), Filter the pretreated wastewater through a 2000-mesh filter cloth to remove the precipitate, and then filter it through a 22-μm filter membrane to remove bacteria to obtain the pre-copper-removed wastewater.

[0052] Clostridium thermocellum was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-72834.

[0053] Thermoanaerobacter ethanolicus was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-117711.

[0054] Rhodopseudomonas palustris was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-78385.

[0055] Deionized water is commercially available, CAS number: 7732-18-5.

[0056] Sodium chloride is commercially available, CAS number: 7647-14-5.

[0057] Peptone is commercially available, CAS number: 73049-73-7.

[0058] Beef extract is commercially available, CAS number: 68990-09-0.

[0059] Snail mucus extract was purchased from Shaanxi Mufan Biotechnology Co., Ltd., water-soluble extract, extraction ratio 10:1.

[0060] Oyster meat extract was purchased from Shaanxi Tianxingjian Biochemical Technology Co., Ltd., water-soluble extract, extraction ratio 10:1.

[0061] Example 3

[0062] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions includes the following steps:

[0063] Step 1), Mix 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 evenly to prepare a nutrient solution. Then inoculate 0.6 g of Clostridium thermocellum, 0.4 g of Thermoanaerobacter ethanolicus, and 0.9 g of Rhodopseudomonas palustris into the nutrient solution. Keep the temperature at 34 °C and perform anaerobic culture until OD600 ≥ 1 to obtain the wastewater treatment bacterial liquid.

[0064] Step 2), Inject the copper-containing wastewater into a container, add the wastewater treatment bacterial liquid. For every 10,000 kg of copper-containing wastewater, 2 kg of wastewater treatment bacterial liquid is injected. Keep the temperature at 32 - 34 °C and perform anaerobic treatment for 7 - 10 days to obtain the pretreated wastewater.

[0065] Step 3), Filter the pretreated wastewater through a 2000-mesh filter cloth to remove the precipitate, and then filter it through a 22-μm filter membrane to remove bacteria to obtain the pre-copper-removed wastewater.

[0066] Clostridium thermocellum was purchased from Beijing BioWin Biotechnology Co., Ltd., platform number: Bio-72834.

[0067] Thermoanaerobacter ethanolicus was purchased from Beijing BioWin Biotechnology Co., Ltd., platform number: Bio-117711.

[0068] Rhodopseudomonas palustris was purchased from Beijing BioWin Biotechnology Co., Ltd., platform number: Bio-78385.

[0069] Deionized water is commercially available, CAS number: 7732-18-5.

[0070] Sodium chloride is commercially available, CAS number: 7647-14-5.

[0071] Peptone is commercially available, CAS number: 73049-73-7.

[0072] Beef extract is commercially available, CAS number: 68990-09-0.

[0073] Snail mucus extract was purchased from Shaanxi Mufan Biotechnology Co., Ltd., water-soluble extract, extraction ratio 10:1.

[0074] Oyster meat extract was purchased from Shaanxi Tianxingjian Biochemical Technology Co., Ltd., water-soluble extract, extraction ratio 10:1.

[0075] Comparative Example 1

[0076] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, compared with Example 2, the difference is only that:

[0077] Brevibacillus parabrevis is used to replace Clostridium thermocellum in equal amount.

[0078] Brevibacillus parabrevis was purchased from Beijing BioWin Biotechnology Co., Ltd., platform number: Bio-049015.

[0079] Comparative Example 2

[0080] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, compared with Example 2, the difference is only that:

[0081] Escherichia coli was used to replace Thermoanaerobacter ethanolicus in equal amounts.

[0082] Escherichia coli was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-60495.

[0083] Comparative Example 3

[0084] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, compared with Example 2, the only difference is that:

[0085] Corynebacterium sepedonicum was used to replace Rhodopseudomonas palustris in equal amounts.

[0086] Corynebacterium sepedonicum was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-62136.

[0087] Comparative Example 4

[0088] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, compared with Example 2, the only difference is that:

[0089] Brevibacillus parabrevis was used to replace Clostridium thermocellum in equal amounts, Escherichia coli was used to replace Thermoanaerobacter ethanolicus in equal amounts, and Corynebacterium sepedonicum was used to replace Rhodopseudomonas palustris in equal amounts.

[0090] Brevibacillus parabrevis was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-049015.

[0091] Escherichia coli was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-60495.

[0092] Corynebacterium sepedonicum was purchased from Beijing Bio-win Biotechnology Co., Ltd., platform number: Bio-62136.

[0093] Comparative Example 5

[0094] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, compared with Example 2, the only difference is that:

[0095] Yeast extract was used to replace snail mucus extract in equal amounts.

[0096] Yeast extract was purchased from Hebei Hongtao Bioengineering Co., Ltd.

[0097] Comparative Example 6

[0098] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, compared with Example 2, the only difference is that:

[0099] Glucose was used to replace oyster meat extract in equal amounts.

[0100] The glucose was purchased from Zhengzhou Yuhe Food Additive Co., Ltd.

[0101] Comparative Example 7

[0102] A method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions, compared with Example 2, the difference is only that:

[0103] Yeast extract was used to replace the snail mucus extract in equal amount, and glucose was used to replace the oyster meat extract in equal amount.

[0104] The yeast extract was purchased from Hebei Hongtao Bioengineering Co., Ltd.

[0105] The glucose was purchased from Zhengzhou Yuhe Food Additive Co., Ltd.

[0106] Experiment 1

[0107] The same batch of sewage was treated by the methods for treating low-concentration PCB copper-containing wastewater under anaerobic conditions in each example and comparative example, and the copper ion content in the treated sewage was detected.

[0108] The sewage for the test was randomly sampled ten times, and the copper ion content in the sewage before being treated by the method for treating low-concentration PCB copper-containing wastewater under anaerobic conditions was detected. The detection results were averaged. The specific copper ion content of the sewage used in this experiment was: 1.543 mg / L.

[0109] Method for detecting the content of copper ions: atomic absorption spectrometry.

[0110] The specific detection data of Experiment 1 are shown in Table 1.

[0111] Table 1

[0112] Copper ion content of the 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

[0113] According to the data comparison of each example and comparative example in Table 1, the copper ion content in the purified sewage of each example is significantly lower than that of each comparative example. Among them, although Comparative Examples 1-4 can reduce the copper ion content, the copper ion content in the finally discharged sewage is greater than 0.5 mg / L, which still belongs to the pollution level and fails to meet the purification standard requirements. In the subsequent treatment steps, chemical components need to be added to further reduce the copper ion content, resulting in a relatively 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 example.

[0114] It can be seen that in Comparative Examples 1-4, the Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris in the Examples were replaced singly or in whole by other strains used for sewage treatment, resulting in a significant decline in the effect of reducing copper ion content. This proves that when Clostridium thermocellum, Thermoanaerobacter ethanolicus, and Rhodopseudomonas palustris are compounded, the activity of each strain in copper ion-polluted wastewater can be significantly improved, the copper ion content in the sewage can be rapidly reduced, and there is no need to add chemical drugs for copper ion removal in the subsequent treatment steps, effectively reducing costs and having higher economic value.

[0115] In addition, in Comparative Examples 5-7, the snail mucus extract and oyster meat extract in the Examples were replaced singly or in whole by other nutrient components, resulting in a decline in the activity of each strain. Therefore, under the same sewage treatment time, the degree of copper ion removal decreased, resulting in a sewage treatment effect inferior to that of each Example.

[0116] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

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 copper-containing wastewater to wastewater treatment bacterial liquid 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.