Microorganism-loaded activated carbon composition, nitrile-containing wastewater pretreatment process and device

Abstract

The invention discloses a microorganism-loaded activated carbon composition, a nitrile-containing wastewater pretreatment process, a nitrile-containing wastewater pretreatment device and a nitrile-containing wastewater pretreatment device, and belongs to the technical field of microorganism culture and sewage treatment devices. Aiming at the technical problems in the prior art that when nitrile-containing wastewater is pretreated by adopting an electro-catalysis internal circulation biological aerated filter, the conductivity and the biodegradation efficiency of a biological filler are poor, only the biodegradability of the wastewater is improved, and organic nitrile cannot be converted into an available substrate, the invention provides the microorganism-loaded activated carbon composition. Comprising activated carbon loaded with Shewanella oneidensis or rhodococcus turbid in a mass ratio of (1: 2)-(1: 3), the quantity of the activated carbon is 10 < 9 >-10 < 10 > CFU / g, and the composition has good conductivity and biodegradation efficiency. The invention further provides a nitrile-containing wastewater pretreatment process and device, the nitrile-containing wastewater pretreatment process comprises the steps that nitrile-containing wastewater is introduced into the device body, electric treatment and micro-nano bubble generator treatment are sequentially carried out, and the nitrile-containing wastewater pretreatment process and device have the advantages of being low in power consumption, low in treatment cost, convenient and safe to operate, green and environmentally friendly in process and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment devices, and more specifically, relates to an activated carbon composition loaded with microorganisms, a nitrile-containing wastewater pretreatment process and a device. Background Art

[0002] Nitrile-containing chemical wastewater refers to wastewater generated during chemical production, especially during the production of acrylic fibers or organic nitrile compounds such as acrylonitrile. This type of wastewater contains a large amount of organic nitrile compounds, such as acrylonitrile, acetonitrile, and acrylonitrile oligomers. The treatment of nitrile-containing chemical wastewater faces multiple problems: (1) Biological inhibition toxicity: Organic nitrile compounds have a strong inhibitory effect on microorganisms. Even low concentrations of nitrile compounds can significantly affect the activity of microorganisms, which limits the application of biological treatment technology. (2) High content of difficult-to-degrade organic matter: The organic matter in nitrile-containing wastewater is often complex in structure and difficult to degrade by conventional biological treatment methods. Pretreatment is required to improve its biodegradability. (3) Low treatment efficiency: Traditional physical, chemical, and biological treatment methods are often unable to effectively remove pollutants in nitrile-containing wastewater, resulting in low treatment efficiency. (4) Cost and operational complexity: Although some efficient treatment technologies, such as membrane treatment technology, have good treatment effects, they have high operating costs and high energy consumption, which limits their widespread application in chemical plant wastewater treatment. (5) Limitations of anaerobic treatment: Anaerobic microorganisms are extremely sensitive to environmental conditions such as pH, temperature and toxicity. Foul-smelling gases may be produced during the treatment process. In addition, the anaerobic treatment system has certain requirements for the biodegradability of wastewater, and the biodegradability of nitrile-containing wastewater is often poor.

[0003] The treatment methods for nitrile-containing chemical wastewater mainly include the following: (1) Chemical oxidation method: by adding oxidants (such as hydrogen peroxide, ozone, liquid chlorine, etc.) to oxidize and decompose organic nitrile compounds in wastewater. The disadvantage is that the cost is high and a large amount of chemical sludge may be produced. (2) Physical treatment method: including filtration method, gravity sedimentation method and flotation method. The process is simple and the management is convenient, but it cannot effectively remove soluble wastewater components and has great limitations. (3) Electrochemical oxidation method: in the electrolytic cell, organic pollutants in wastewater undergo redox reactions on the electrodes and are removed. There are problems such as high energy consumption, high cost, and side reactions. (4) Biological method: including SBR method, biological contact oxidation method, aerobic biochemical method, acidification pretreatment, biological filtration and addition of special bacteria. It can reduce the content of organic matter in wastewater and improve its biodegradability, but the degradation ability of organic nitrile is limited and the treatment efficiency may not be high. (5) Photocatalytic oxidation technology: using light-induced oxidation to combine oxidants with light radiation, it can treat difficult-to-degrade substances. There may be problems with high equipment cost and complex operation. (6) Adsorption method: such as activated carbon adsorption, resin adsorption, etc., which can effectively remove organic matter from wastewater. The disadvantage is that the adsorbent is difficult to regenerate, and there may be a problem of limited adsorption capacity. (7) Fenton oxidation method: The treatment efficiency is high, but a large amount of reagents need to be added, which is costly and easy to produce a large amount of chemical sludge. In addition, many pollutants cannot be completely degraded, and a large amount of intermediate products are produced. The effluent often cannot meet the reuse requirements. (8) Electrocatalytic internal circulation aerated biological filter: Combining three-dimensional electrode advanced oxidation technology and biofilm technology, it can effectively treat difficult-to-degrade industrial wastewater. However, the equipment investment of this method may be high, and the operation and maintenance are complicated.

[0004] Among the above methods, the electrocatalytic internal circulation aerated biological filter method has a relatively high pollutant removal capacity and a strong impact load resistance compared to other methods. The Chinese invention application publication number is CN113511719A, the application date is April 10, 2020, and the invention name is "Electrocatalytic internal circulation aerated biological filter and wastewater aeration method". The disclosed electrocatalytic internal circulation aerated biological filter includes: a tank body, which is at least partially open on the top; a support structure, which divides the tank body into an upper space and a lower space, and can allow water to pass; a catalyst layer, which is arranged in the upper space; a biological filler layer, which is stacked with the catalyst layer and arranged below the catalyst layer; a guide tube, which runs through each layer and is connected to the lower space; an aeration unit, which is arranged at the bottom of the guide tube; a water inlet unit, which is arranged at the bottom of the tank body; and an electrode, which is arranged in the catalyst layer. This scheme can integrate three-dimensional electrode advanced oxidation technology with biofilm technology, but it has the following shortcomings: (1) It only improves the biodegradability of wastewater, fails to convert organic nitrile into a substrate that can be used by the subsequent anaerobic treatment system, and fails to improve the treatment efficiency and methane production of the anaerobic system. (2) The applied voltage (or current density) is conventional, which is not energy-saving and environmentally friendly. (3) Ordinary activated sludge is used and conventional aeration is performed, and it is not reported whether it has a positive and clear promoting effect on the subsequent anaerobic system.

[0005] Therefore, developing an efficient, economical and easy-to-operate method for treating nitrile-containing chemical wastewater to reduce its negative impact on the anaerobic treatment system is a technical problem that needs to be urgently solved in the current sewage treatment field. Summary of the invention

[0006] 1. Problem to be solved

[0007] In view of the technical problems that in the prior art, when nitrile-containing wastewater is pretreated by an electrocatalytic internal circulation aerated biological filter, the conductivity and biodegradation efficiency of the biological filler are poor, and the biodegradability of the wastewater is only improved but the organic nitrile cannot be converted into an available substrate, the present invention provides an activated carbon composition loaded with microorganisms;

[0008] Furthermore, the present invention also provides a pretreatment device for nitrile-containing wastewater;

[0009] At the same time, the invention also provides a pretreatment process for nitrile-containing wastewater.

[0010] 2. Technical solution

[0011] The technical solution adopted by the present invention is as follows:

[0012] Based on the purpose of the present invention, the first aspect of the present invention provides an activated carbon composition loaded with microorganisms, including activated carbon loaded with Oneida Lake Shewanella and activated carbon loaded with opaque Rhodococcus; the mass ratio of the activated carbon loaded with Oneida Lake Shewanella to the activated carbon loaded with opaque Rhodococcus is 1:2 to 1:3;

[0013] Oneida Lake Shewanella count is 10 9 ~10 10 CFU / g; the number of opaque Rhodococcus is 10 9 ~10 10 CFU / g.

[0014] As described herein, Shewanella from Oneida Lake can form a biofilm in an electrified system, adhere to and aggregate on the electrode surface. When the nitrile-containing wastewater pretreatment device is electrified, a large number of microelectrodes will be formed on the granular activated carbon, and Shewanella from Oneida Lake will adhere to the surface of the activated carbon, while secreting a large amount of extracellular polymers to assist the colonization of Rhodococcus turbidus. At the same time, Shewanella from Oneida Lake has good electron transfer ability, which can improve the conductivity. Rhodococcus turbidus can produce nitrile hydratase and amidase, catalyze the degradation and transformation of organic nitriles in wastewater, relieve the biological inhibition toxicity of chemical wastewater, and facilitate the efficient treatment of subsequent anaerobic systems.

[0015] As described herein, activated carbon functions as follows: (1) as a colonization carrier for functional microorganisms, ensuring that the functional microorganisms are not easily lost. (2) in the case of combined electrical treatment, it has a conductive effect, and when filled in a nitrile-containing wastewater pretreatment device, a large number of micro-electrodes will be formed after power is applied, which improves the reaction efficiency and helps accelerate the biofilm formation of Shewanella spp. in Oneida Lake.

[0016] According to the microorganism-loaded activated carbon composition of any embodiment of the first aspect of the present invention, the Shewanella oneidensis is deposited in the China Industrial Microbiological Culture Collection Center with a deposit number of CICC 25104; the Rhodococcus opacus is deposited in the American Type Culture Collection with a deposit number of ATCC 51882.

[0017] According to any embodiment of the first aspect of the present invention, the activated carbon composition loaded with microorganisms has a particle size of 5 to 10 mm for the activated carbon loaded with Oneida Lake Shewanella and a particle size of 2 to 6 mm for the activated carbon loaded with Rhodococcus opacus.

[0018] Preparation method of activated carbon composition loaded with microorganisms:

[0019] Oneida Lake Shewanella was inoculated into tryptone soy broth medium and cultured at 30°C until the logarithmic growth phase. Sterile activated carbon particles with a particle size of 5 to 10 mm were added to the bacterial solution. The amount of activated carbon added was 100 g per liter of bacterial solution. After incubation for 10 to 16 hours, the granular activated carbon was removed and air-dried in a cool place until the number of Oneida Lake Shewanella on the activated carbon was 10 9 ~10 10 CFU / g, and activated carbon loaded with Oneida Lake Shewanella was obtained.

[0020] Inoculate opacified Rhodococcus into tryptone soy broth medium and culture at 26°C until the logarithmic growth phase. Add sterile activated carbon particles with a particle size of 2 to 6 mm to the bacterial solution. The amount of activated carbon added is 100 g per liter of bacterial solution. After incubation for 16 to 24 hours, remove the granular activated carbon and air-dry it in a cool place until the number of opacified Rhodococcus on the activated carbon is 10 9 ~10 10 CFU / g, and activated carbon loaded with opaque Rhodococcus was obtained.

[0021] The activated carbon loaded with Oneida Lake Shewanella and the activated carbon loaded with opaque Rhodococcus are uniformly mixed in a mass ratio of 1:2 to 1:3 to obtain an activated carbon composition loaded with microorganisms.

[0022] Based on the purpose of the present invention, the second aspect of the present invention provides a nitrile-containing wastewater pretreatment device, comprising a device body, wherein the device body is provided with an anode and a cathode arranged in parallel, and the anode and the cathode are connected by a power supply;

[0023] The space between the anode and cathode is filled with the activated carbon composition loaded with microorganisms; and the device body is also provided with a micro-nano bubble generator.

[0024] Preferably, a water inlet pipe is provided at the lower part of the device body, and a water outlet pipe is provided at the upper part of the device body.

[0025] Preferably, the anode is a ruthenium-iridium-titanium electrode, and the cathode is a stainless steel electrode.

[0026] Preferably, a screen is also provided at the water outlet pipe.

[0027] According to the nitrile-containing wastewater pretreatment device of any embodiment of the second aspect of the present invention, the filling volume of the activated carbon composition loaded with microorganisms accounts for 1 / 2 to 2 / 3 of the volume of the device body.

[0028] Based on the purpose of the present invention, the third aspect of the present invention provides a nitrile-containing wastewater pretreatment process, using the nitrile-containing wastewater pretreatment device, comprising the steps of:

[0029] S1, introducing nitrile-containing wastewater into the device body, turning on the power supply, and keeping the micro-nano bubble generator closed;

[0030] S2, turning off the power supply, and the micro-nano bubble generator starts to operate;

[0031] S3, closing the micro-nano bubble generator and allowing the mixture to settle.

[0032] The nitrile-containing wastewater pretreatment process according to any embodiment of the second aspect of the present invention is characterized in that: in step S1, the current density on the anode and the cathode is controlled to be 7-15 mA / cm 2 .

[0033] Preferably, a direct current power supply is used, and the power-on time of the power supply lasts for 10 to 20 minutes.

[0034] As described herein, the electrolysis reaction is carried out by connecting an external DC power supply, which has the following effects: (1) an oxidation reaction occurs directly at the anode to oxidize the organic matter in the wastewater. (2) the external voltage can stimulate the activity of nitrile hydratase and amidase of Rhodococcus turbidus, and the organic nitrile in the wastewater can be converted into volatile organic acids, which can be directly used by the subsequent anaerobic system, which is beneficial to improve the treatment efficiency and methane production of the subsequent anaerobic system. (3) a small amount of hydroxyl radicals can be generated at the anode, which is beneficial to the oxidation and degradation of organic matter in the wastewater.

[0035] The nitrile-containing wastewater pretreatment process according to any embodiment of the second aspect of the present invention is characterized in that: in step S2, the particle size of the micro-nano bubbles generated by the micro-nano bubble generator is 50-100 μm.

[0036] Preferably, the ventilation operation time is 15 to 25 minutes.

[0037] As described herein, the use of micro-nano bubbles as a gas source has the following effects: (1) Micro-nano bubbles stay in water for a long time and can provide the inoculated functional microorganisms with the oxygen necessary for growth and reproduction. (2) Micro-nano bubbles can form a certain amount of hydroxyl free radicals, which is beneficial for the oxidation reaction of complex compounds in chemical wastewater. (3) Micro-nano bubbles have a large specific surface area and can adsorb organic matter and trace elements in water. After sufficient contact with functional microorganisms, they are beneficial for improving the degradation efficiency of organic matter in wastewater by microorganisms. (4) After the water containing micro-nano bubbles enters the subsequent anaerobic system, it can stimulate the reproduction of facultative anerobic microorganisms in the subsequent anaerobic system, produce more extracellular enzymes, enhance the hydrolysis and acidification process of the subsequent anaerobic system, and improve the treatment efficiency of the subsequent anaerobic system.

[0038] The nitrile-containing wastewater pretreatment process according to any embodiment of the second aspect of the present invention is characterized in that: in step S3, the static sedimentation time is ≥5 min.

[0039] According to any embodiment of the second aspect of the present invention, the nitrile-containing wastewater pretreatment process is characterized in that the hydraulic retention time is controlled to be 7 to 8 hours, the pH value is controlled to be 7.2 to 7.8 during operation, and the operating temperature is controlled to be 26 to 30°C.

[0040] 3. Beneficial effects

[0041] (1) The activated carbon composition loaded with microorganisms of the present invention: a. By loading the activated carbon composition with Oneida Lake Shewanella and Ophelia opaca, the synergistic effect of these two microorganisms is utilized to effectively degrade organic nitrile compounds in nitrile-containing chemical wastewater. Oneida Lake Shewanella has good electron transfer ability, while Ophelia opaca can produce nitrile hydratase and amidase, which can catalyze the degradation and transformation of organic nitriles, thereby relieving the biological inhibition toxicity of wastewater. b. Oneida Lake Shewanella can form a biofilm in an electrified system and adhere to and aggregate on the electrode surface. The formation of this biofilm helps to improve the conductivity efficiency, making the electrocatalytic oxidation process more efficient. c. The large amount of extracellular polymers secreted by Oneida Lake Shewanella helps the colonization of Ophelia opaca to form a stable biofilm. This stable biofilm structure is beneficial to the long-term activity of microorganisms and the continuity of wastewater treatment. d. The number of Oneida Lake Shewanella and Ophelia opaca is both above 10 9 ~10 10 CFU / g range, this high concentration of microbial load helps to improve the efficiency and stability of wastewater treatment. e. It does not produce secondary pollution and is an environmentally friendly wastewater treatment technology. Through the combination of biodegradation and electrocatalytic oxidation, organic nitrile compounds can be effectively removed while reducing the use of chemical agents. f. The biological inhibition toxicity is eliminated, which is conducive to the efficient treatment of the subsequent anaerobic system. This not only improves the overall treatment efficiency of wastewater, but also helps to reduce the cost of subsequent treatment.

[0042] (2) The nitrile-containing wastewater pretreatment device of the present invention: a. By setting parallel anodes and cathodes and filling an activated carbon composition loaded with microorganisms, the electrocatalytic oxidation technology can be effectively used to degrade organic pollutants in nitrile-containing wastewater. b. The micro-nano bubble generator integrated in the device can generate a large number of micro-nano bubbles, increase the gas-liquid contact area, improve the oxygen transfer efficiency, and thus enhance the biological treatment effect. c. The design of the device simplifies the operation process, has a high degree of automation, reduces manual intervention, and at the same time, reduces maintenance costs and frequency.

[0043] (3) The pretreatment process of nitrile-containing wastewater of the present invention: a. Organic nitriles are converted into volatile organic acids, which can be directly used as substrates for anaerobic reactions, thereby improving the methane production capacity and COD degradation efficiency of the subsequent anaerobic system. b. Compared with the traditional electrolytic cell pretreatment reactor, the external voltage of the present application is mainly used to stimulate the growth of functional microorganisms and enhance the activity of degradation enzymes, so the power consumption is low and the treatment cost is low. c. The operation steps of this process are simple and easy to control, and a DC power supply is used to ensure the simplicity and safety of the operation process. d. This process does not produce secondary pollution and is an environmentally friendly wastewater treatment technology that meets the requirements of green and environmentally friendly sustainable development. e. The process can ensure the high efficiency and stability of wastewater treatment by precisely controlling the power-on time, the particle size of the micro-nano bubbles, the ventilation operation time, and the static sedimentation time.

[0044] Instruction Manual

[0045] Figure 1 This is a schematic diagram of the structure of a nitrile-containing wastewater pretreatment device in an embodiment of the present application;

[0046] In the figure:

[0047] 1. Device body; 2. Water inlet pipe; 3. Water outlet pipe; 4. Anode; 5. Cathode; 6. Power supply; 7. Activated carbon composition loaded with microorganisms; 8. Micro-nano bubble generator; 9. Screen. DETAILED DESCRIPTION

[0048] All documents cited in the present invention are incorporated herein by reference in their entirety, and if the meanings expressed in these documents are inconsistent with the present invention, the description of the present invention shall prevail. In addition, the various terms and phrases used in the present invention have the general meanings known to those skilled in the art. Even so, the present invention still hopes to provide a more detailed description and explanation of these terms and phrases. If the terms and phrases mentioned are inconsistent with the known meanings, the meanings expressed in the present invention shall prevail.

[0049] When items are described by using the conjunction terms "... and / or...," etc., the description should be understood to include any one of the associated listed items and all combinations of one or more thereof.

[0050] In general, the use of the term "about" indicates an approximate value that may vary depending on the desired properties obtained by the disclosed subject matter, and will be interpreted in a context-dependent manner based on function. Therefore, one of ordinary skill in the art will be able to interpret a certain degree of difference on a case-by-case basis. In some cases, the number of significant figures used when expressing a particular value can be a representative technique for determining the difference allowed by the term "about". In other cases, a gradient in a range of values ​​can be used to determine the range of differences allowed by the term "about". Further, all ranges in this disclosure are inclusive and combinable, and reference to the values ​​stated in the range includes each value within the range.

[0051] In the present invention, the term "comprising" or "containing" means that various components can be used together in the composition of the present invention. Therefore, the terms "consisting mainly of" and "consisting of" are included in the terms "comprising" or "containing".

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs; the terms used herein and / or include any and all combinations of one or more of the associated listed items.

[0053] The following will disclose any feature in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. Unless otherwise stated, each feature is just an example in a series of equivalent or similar features. It is described only to help understand the present invention and should not be regarded as a specific limitation of the present invention. Those who do not indicate specific conditions in the embodiment are carried out according to normal conditions or the conditions recommended by the manufacturer. Those who do not indicate the manufacturer of the reagents or instruments used are all conventional products that can be purchased.

[0054] The present invention is further described below in conjunction with specific embodiments.

[0055] Example 1

[0056] This embodiment provides an activated carbon composition loaded with microorganisms and a nitrile-containing wastewater pretreatment process, which is implemented using a nitrile-containing wastewater pretreatment device, and its structural schematic diagram is shown in FIG. Figure 1 As shown,

[0057] The device body 1 of the nitrile-containing wastewater pretreatment device comprises a water inlet pipe 2 arranged at the lower part and a water inlet pipe 3 arranged at the upper part. Electrode sheets, namely anode 4 and cathode 5, are inserted into the device body 1 and connected by a power supply 6. In this embodiment, a DC power supply is used. Anode 4 is a ruthenium iridium titanium electrode, cathode 5 is a stainless steel electrode, and anode 4 and cathode 5 are placed relatively parallel.

[0058] The space between the anode 4 and the cathode 5 is filled with an activated carbon composition 7 loaded with microorganisms, the filling volume of the activated carbon composition 7 loaded with microorganisms accounts for 1 / 2 to 2 / 3 of the effective volume, 2 / 3 in this embodiment, and the remaining volume is filled with the nitrile-containing chemical wastewater to be treated.

[0059] A micro-nano bubble generator 8 is disposed at the bottom of the device body 1 .

[0060] In this embodiment, a water bath jacket is arranged outside the device body 1 to adjust the operating temperature inside the device body 1 .

[0061] A screen 9 is provided below the water outlet pipe 3 of the device body 1 to intercept the activated carbon composition 7 loaded with microorganisms and prevent the activated carbon composition 7 loaded with microorganisms from being lost.

[0062] Preparation method of the activated carbon composition 7 loaded with microorganisms in the device body 1:

[0063] Oneida Lake Shewanella was inoculated into tryptone soy broth medium and cultured at 30°C until the logarithmic growth phase. Sterile activated carbon particles with a particle size of 5 to 10 mm were added to the bacterial solution. The amount of activated carbon added was 100 g per liter of bacterial solution. After incubation for 10 to 16 hours, the granular activated carbon was removed and air-dried in a cool place until the number of Oneida Lake Shewanella on the activated carbon was 10 9 ~10 10 CFU / g, and activated carbon loaded with Oneida Lake Shewanella was obtained.

[0064] Inoculate opacified Rhodococcus into tryptone soy broth medium and culture at 26°C until the logarithmic growth phase. Add sterile activated carbon particles with a particle size of 2 to 6 mm to the bacterial solution. The amount of activated carbon added is 100 g per liter of bacterial solution. After incubation for 16 to 24 hours, remove the granular activated carbon and air-dry it in a cool place until the number of opacified Rhodococcus on the activated carbon is 10 9 ~10 10 CFU / g, and activated carbon loaded with opaque Rhodococcus was obtained.

[0065] The activated carbon loaded with Oneida Lake Shewanella and the activated carbon loaded with Rhodococcus opacus were uniformly mixed in a mass ratio of 1:2 to 1:3 to obtain the microorganism loaded activated carbon composition 7. The ratio used in this embodiment is 1:2.

[0066] The pretreatment process steps of nitrile-containing wastewater are as follows:

[0067] The chemical wastewater containing acrylonitrile is continuously and evenly introduced from the water inlet pipe 2 at the bottom of the device body 1, and the hydraulic retention time is controlled to be 8 hours. During the operation process, the pH in the nitrile wastewater pretreatment device is controlled to be 7.8, and the operating temperature of the nitrile wastewater pretreatment device can be controlled to be 30°C. The operation of the nitrile wastewater pretreatment device is divided into three stages and is continuously circulated.

[0068] Stage 1: The external DC power supply 6 of the nitrile-containing wastewater pretreatment device is powered on, the micro-nano bubble generator 8 is not running, and the current density on the anode 4 and the cathode 5 is controlled to be 7 mA / cm when the DC power supply 9 is powered on. 2 , the power-on time lasts for 15 minutes.

[0069] Stage 2: The external DC power supply 9 of the nitrile-containing wastewater pretreatment device is powered off, and the micro-nano bubble generator 8 starts to operate, and micro-nano bubbles with a particle size of 50 to 100 μm are introduced into the nitrile-containing wastewater pretreatment device, and the ventilation operation time is 20 minutes.

[0070] Stage 3: The external DC power supply 9 and the micro-nano bubble generator 8 of the nitrile-containing wastewater pretreatment device are not in operation, and the device is left to settle for 5 minutes.

[0071] The COD and acrylonitrile contents of nitrile-containing wastewater before and after pretreatment are determined as follows:

[0072]

[0073] The wastewater treated by the nitrile-containing wastewater pretreatment device was added to the anaerobic sludge, with the volume ratio of wastewater to anaerobic sludge being 1:4. After being mixed and stirred evenly, the mixture was incubated at 35°C for 48 hours, and the cumulative methane production, coenzyme F420 concentration, and COD removal rate of the anaerobic sludge were determined. The results are as follows:

[0074]

[0075] Example 2

[0076] The microorganism-loaded activated carbon composition and the nitrile-containing wastewater pretreatment process provided in this embodiment use the nitrile-containing wastewater pretreatment device in Example 1, and the specific steps are as follows:

[0077] Oneida Lake Shewanella was inoculated into tryptone soy broth medium and cultured at 30°C until the logarithmic growth phase. Sterile activated carbon particles with a particle size of 5 mm were added to the bacterial solution. The amount of activated carbon added was 100 g per liter of bacterial solution. After incubation for 10 hours, the granular activated carbon was removed and air-dried in a cool place until the number of Oneida Lake Shewanella on the activated carbon was about 10 9 CFU / g, and activated carbon loaded with Oneida Lake Shewanella was obtained. The opaque Rhodococcus was inoculated into a tryptone soy broth medium and cultured at 26°C until the logarithmic growth phase. Sterile activated carbon particles with a particle size of 2 mm were added to the bacterial solution. The amount of activated carbon added per liter of bacterial solution was 100 g. After incubation for 16 hours, the granular activated carbon was removed and air-dried in a cool place until the number of opaque Rhodococcus on the activated carbon was about 10 9CFU / g, and the activated carbon loaded with opaque Rhodococcus was obtained. The activated carbon loaded with Oneida Lake Shewanella and the activated carbon loaded with opaque Rhodococcus were uniformly mixed in a mass ratio of 1:3 to obtain the activated carbon composition 7 loaded with microorganisms.

[0078] The volume of the activated carbon composition 7 loaded with microorganisms accounts for 1 / 2 of the volume of the device body 1, and the remaining volume is filled with the chemical wastewater containing acrylonitrile to be treated. The chemical wastewater containing acrylonitrile is continuously and evenly introduced from the water inlet pipe 2 at the bottom of the nitrile wastewater pretreatment device, and the hydraulic retention time is controlled to be 7h. During the operation process, the pH in the nitrile wastewater pretreatment device is controlled to be 7.2, and the operating temperature is controlled to be 30°C. The operation of the nitrile wastewater pretreatment device is divided into three stages and is continuously circulated.

[0079] Stage 1: The external DC power supply 6 of the nitrile-containing wastewater pretreatment device is powered on, and the micro-nano bubble generator 8 is not running. When the DC power supply 6 is powered on, the current density on the control electrode is 15 mA / cm 2 , the power-on time lasts for 15 minutes.

[0080] Stage 2: The external DC power supply 6 of the nitrile-containing wastewater pretreatment device is powered off, and the micro-nano bubble generator 8 starts to operate, and micro-nano bubbles with a particle size of 50 to 100 μm are introduced into the nitrile-containing wastewater pretreatment device, and the ventilation operation time is 20 minutes.

[0081] Stage 3: The external DC power supply 6 and the micro-nano bubble generator 8 of the nitrile-containing wastewater pretreatment device are not in operation, and the device is left to settle for 5 minutes.

[0082] The COD and acrylonitrile contents of nitrile-containing wastewater before and after pretreatment are determined as follows:

[0083]

[0084] The wastewater treated by the nitrile-containing wastewater pretreatment device was added to the anaerobic sludge, with the volume ratio of wastewater to anaerobic sludge being 1:4. After being mixed and stirred evenly, the mixture was incubated at 35°C for 48 hours, and the cumulative methane production, coenzyme F420 concentration, and COD removal rate of the anaerobic sludge were determined. The results are as follows:

[0085]

[0086] Comparative Example 1

[0087] The nitrile-containing wastewater treatment device of this comparative example is basically the same as Example 1, except that ordinary activated carbon is filled between the electrodes, and the volume of activated carbon filling accounts for 2 / 3 of the effective volume of the device, and the remaining volume is filled with chemical wastewater containing acrylonitrile to be treated. Chemical wastewater containing acrylonitrile is continuously and evenly introduced from the bottom of the device, and the hydraulic retention time is controlled to be 8h. During the operation, the pH in the nitrile-containing wastewater treatment device is controlled to be 7.5, and the operating temperature can be controlled to be 30°C. The operation is divided into 3 stages, which are continuously circulated.

[0088] Stage 1: The device is powered by an external DC power supply, the micro-nano bubble generator is not running, and the current density on the control electrode is 7mA / cm 2 , the power-on time lasts for 15 minutes.

[0089] Stage 2: The external DC power supply of the device is cut off, and the micro-nano bubble generator starts to operate, introducing micro-nano bubbles with a particle size of 50 to 100 μm into the device, and the ventilation operation time is 20 minutes.

[0090] Stage 3: The device’s external DC power supply and micro-nano bubble generator are not in operation, and the device is left to settle for 5 minutes.

[0091] The COD and acrylonitrile contents before and after treatment by the measuring device are as follows:

[0092]

[0093] The treated wastewater was added to the anaerobic sludge at a volume ratio of 1:4. After being mixed and stirred evenly, the mixture was incubated at 35°C for 48 hours. The cumulative methane production, coenzyme F420 concentration, and COD removal rate of the anaerobic sludge were measured. The results are as follows:

[0094]

[0095] Comparative Example 2

[0096] The microorganism-loaded activated carbon composition of this comparative example was prepared as follows: Oneida Lake Shewanella was inoculated into a tryptone soy broth medium and cultured at 30°C until the logarithmic growth phase, and sterile activated carbon particles with a particle size of 10 mm were added to the bacterial solution. The amount of activated carbon added per liter of bacterial solution was 100 g. After incubation for 16 hours, the granular activated carbon was removed and air-dried in a cool place until the number of Oneida Lake Shewanella on the activated carbon was about 10 10CFU / g, and activated carbon loaded with Oneida Lake Shewanella was obtained. The opacified Rhodococcus was inoculated into a tryptone soy broth medium and cultured at 26°C until the logarithmic growth phase. Sterile activated carbon particles with a particle size of 5 mm were added to the bacterial solution. The amount of activated carbon added per liter of bacterial solution was 100 g. After incubation for 24 hours, the granular activated carbon was removed and air-dried in a cool place until the number of opacified Rhodococcus on the activated carbon was about 10 10 CFU / g, and the activated carbon loaded with opaque Rhodococcus was obtained. The activated carbon loaded with Oneida Lake Shewanella and the activated carbon loaded with opaque Rhodococcus were uniformly mixed in a mass ratio of 1:2 to obtain an activated carbon composition loaded with microorganisms.

[0097] The wastewater pretreatment device of this comparative example is basically the same as that of Example 1, except that a micro-nano bubble generator is not provided in the device, but an aeration tube is used, and a common air compressor is used for aeration and oxygenation. The electrodes of the device are filled with an activated carbon composition loaded with microorganisms, and the filling volume of the activated carbon composition loaded with microorganisms accounts for 2 / 3 of the effective volume of the device, and the remaining volume is filled with chemical wastewater containing acrylonitrile to be treated. The chemical wastewater containing acrylonitrile is continuously and evenly introduced from the bottom of the device, and the hydraulic retention time is controlled to be 8h. The pH in the device is controlled to be 7.5 during the operation process, and the operating temperature is controlled to be 30°C. The operation of the device is divided into 3 stages, which are continuously circulated.

[0098] Stage 1: The device is powered by an external DC power supply, the aeration air compressor is not running, and the current density on the control electrode is 7mA / cm 2 , the power-on time lasts for 15 minutes.

[0099] Stage 2: The external DC power supply of the device is cut off, and the aeration air compressor starts to run, and air is introduced into the device. The ventilation flow rate is 20L / min, and the ventilation operation time is 20min.

[0100] Stage 3: The device’s external DC power supply and aeration air compressor are not running, and it is left to settle for 5 minutes.

[0101] The COD and acrylonitrile contents before and after biological pretreatment were determined as follows:

[0102]

[0103] The treated wastewater was added to the anaerobic sludge at a volume ratio of 1:4. After being mixed and stirred evenly, the mixture was incubated at 35°C for 48 hours. The cumulative methane production, coenzyme F420 concentration, and COD removal rate of the anaerobic sludge were measured. The results are as follows

[0104]

[0105] Comparative Example 3

[0106] The microorganism-loaded activated carbon composition of this comparative example was prepared as follows: Oneida Lake Shewanella was inoculated into a tryptone soy broth medium and cultured at 30°C until the logarithmic growth phase, and sterile activated carbon particles with a particle size of 10 mm were added to the bacterial solution. The amount of activated carbon added per liter of bacterial solution was 100 g. After incubation for 16 hours, the granular activated carbon was removed and air-dried in a cool place until the number of Oneida Lake Shewanella on the activated carbon was about 10 10 CFU / g, and activated carbon loaded with Oneida Lake Shewanella was obtained. The opacified Rhodococcus was inoculated into a tryptone soy broth medium and cultured at 26°C until the logarithmic growth phase. Sterile activated carbon particles with a particle size of 5 mm were added to the bacterial solution. The amount of activated carbon added per liter of bacterial solution was 100 g. After incubation for 24 hours, the granular activated carbon was removed and air-dried in a cool place until the number of opacified Rhodococcus on the activated carbon was about 10 10 CFU / g, and the activated carbon loaded with opaque Rhodococcus was obtained. The activated carbon loaded with Oneida Lake Shewanella and the activated carbon loaded with opaque Rhodococcus were uniformly mixed in a mass ratio of 1:2 to obtain an activated carbon composition loaded with microorganisms.

[0107] The nitrile-containing wastewater pretreatment device of this comparative example is basically the same as Example 1. The electrodes of the device are filled with an activated carbon composition loaded with microorganisms, and the filling volume of the activated carbon composition loaded with microorganisms accounts for 2 / 3 of the effective volume of the device, and the remaining volume is filled with chemical wastewater containing acrylonitrile to be treated. The chemical wastewater containing acrylonitrile is continuously and evenly introduced from the bottom of the nitrile-containing wastewater pretreatment device, and the hydraulic retention time is controlled to be 8h. During the operation process, the pH in the nitrile-containing wastewater pretreatment device is controlled to be 7.5, and the operating temperature is controlled to be 30°C. When the nitrile-containing wastewater pretreatment device is in operation, the external DC power supply is always energized, and the current density on the control electrode is controlled to be 20mA / cm 2 .

[0108] The COD and acrylonitrile contents before and after biological pretreatment were determined as follows:

[0109]

[0110] The pretreated wastewater was added to the anaerobic sludge at a volume ratio of 1:4. After being mixed and stirred evenly, the mixture was incubated at 35°C for 48 hours. The cumulative methane production, coenzyme F420 concentration, and COD removal rate of the anaerobic sludge were measured. The results are as follows:

[0111]

[0112] Comparative Example 4

[0113] Oneida Lake Shewanella was inoculated into tryptone soy broth medium and cultured at 30°C until the logarithmic growth phase. Sterile activated carbon particles with a particle size of 10 mm were added to the bacterial solution. The amount of activated carbon added was 100 g per liter of bacterial solution. After incubation for 16 hours, the granular activated carbon was removed and air-dried in a cool place until the number of Oneida Lake Shewanella on the activated carbon was about 10 10 CFU / g, recorded as functional activated carbon A.

[0114] Functional activated carbon A is filled between the electrodes of the biological pretreatment reactor. The filling volume of activated carbon A accounts for 2 / 3 of the effective volume, and the remaining volume is filled with chemical wastewater containing acrylonitrile to be treated. The chemical wastewater containing acrylonitrile is continuously and evenly introduced from the bottom of the reactor, and the hydraulic retention time is controlled to be 8h. During the operation process, the pH in the reactor is controlled to be 7.8, and the operating temperature of the reactor can be controlled to be 30°C. The operation of the reactor is divided into 3 stages and is continuously circulated. Stage 1: The reactor is powered on by an external DC power supply, the micro-nano bubble generator is not running, and the current density on the control electrode is 7mA / cm 2 , the power-on time lasts for 15 minutes. Stage 2: The external DC power supply of the reactor is turned off, and the micro-nano bubble generator starts to operate, introducing micro-nano bubbles with a particle size of 50 to 100 μm into the reactor, and the ventilation operation time is 20 minutes. Stage 3: The external DC power supply of the reactor and the micro-nano bubble generator are not operated, and the reactor is left to settle for 5 minutes.

[0115] The COD and acrylonitrile contents before and after treatment in the biological pretreatment reactor were determined as follows:

[0116]

[0117] The wastewater treated by the biological pretreatment reactor was added to the anaerobic sludge, and the volume ratio of wastewater to anaerobic sludge was 1:4. After being mixed and stirred evenly, the mixture was incubated at 35°C for 48 hours, and the cumulative methane production, coenzyme F420 concentration, and COD removal rate of the anaerobic sludge to the wastewater were measured. The results are as follows:

[0118]

[0119] Comparative Example 5

[0120] The opacified Rhodococcus was inoculated into tryptone soy broth medium and cultured at 26°C to the logarithmic growth phase. Sterile activated carbon particles with a particle size of 5 mm were added to the bacterial solution. The amount of activated carbon added per liter of bacterial solution was 100 g. After incubation for 24 hours, the granular activated carbon was removed and air-dried in a cool place until the number of opacified Rhodococcus on the activated carbon was about 1010 CFU / g, which was recorded as functional activated carbon B.

[0121] Functional activated carbon B is filled between the electrodes of the biological pretreatment reactor, and the filling volume of activated carbon B accounts for 2 / 3 of the effective volume, and the remaining volume is filled with chemical wastewater containing acrylonitrile to be treated. Chemical wastewater containing acrylonitrile is continuously and evenly introduced from the bottom of the reactor, and the hydraulic retention time is controlled to be 8h. The pH in the reactor is controlled to be 7.8 during the operation process, and the operating temperature of the reactor can be controlled to be 30℃. The operation of the reactor is divided into three stages and is continuously circulated. Stage 1: The reactor is powered on by an external DC power supply, and the micro-nano bubble generator is not running. When the DC power supply is powered on, the current density on the electrode is controlled to be 7mA / cm2, and the power-on time lasts for 15min. Stage 2: The external DC power supply of the reactor is powered off, and the micro-nano bubble generator starts to run, and micro-nano bubbles with a particle size of 50-100μm are introduced into the reactor. The ventilation operation time is 20min. Stage 3: The external DC power supply and the micro-nano bubble generator of the reactor are not running, and the sedimentation is allowed to stand for 5min.

[0122] The COD and acrylonitrile contents before and after treatment in the biological pretreatment reactor were determined as follows:

[0123]

[0124] The wastewater treated by the biological pretreatment reactor was added to the anaerobic sludge, and the volume ratio of wastewater to anaerobic sludge was 1:4. After being mixed and stirred evenly, the mixture was incubated at 35°C for 48 hours, and the cumulative methane production, coenzyme F420 concentration, and COD removal rate of the anaerobic sludge to the wastewater were measured. The results are as follows:

[0125]

Claims

1. An activated carbon composition loaded with microorganisms, characterized in that: The invention comprises activated carbon loaded with Oneida Lake Shewanella and activated carbon loaded with opaque Rhodococcus; the mass ratio of the activated carbon loaded with Oneida Lake Shewanella to the activated carbon loaded with opaque Rhodococcus is 1:2 to 1:3; Oneida Lake Shewanella count is 10 9 ~10 10 CFU / g; the number of opaque Rhodococcus is 10 9 ~10 10 CFU / g.

2. The microorganism-loaded activated carbon composition according to claim 1, characterized in that: The Shewanella oneidensis is deposited in the China Industrial Microbiological Culture Collection Center with a deposit number of CICC 25104; the Rhodococcus opacus is deposited in the American Type Culture Collection with a deposit number of ATCC 51882.

3. The microorganism-loaded activated carbon composition according to claim 1, characterized in that: The particle size of the activated carbon loaded with Oneida Lake Shewanella is 5 to 10 mm; the particle size of the activated carbon loaded with opaque Rhodococcus is 2 to 6 mm.

4. A nitrile-containing wastewater pretreatment device, characterized in that: The device comprises a device body (1), wherein an anode (4) and a cathode (5) are arranged in parallel, and the anode (4) and the cathode (5) are connected via a power source (6); The anode (4) and the cathode (5) are filled with The microorganism-loaded activated carbon composition (7) as described in any one of claims 1 to 3; the device body (1) is also provided with a micro-nano bubble generator (8).

5. The nitrile-containing wastewater pretreatment device according to claim 4, characterized in that: The filling volume of the microorganism-loaded activated carbon composition (7) accounts for 1 / 2 to 2 / 3 of the volume of the device body (1).

6. A process for pretreatment of nitrile-containing wastewater, characterized in that: The nitrile-containing wastewater pretreatment device according to any one of claims 4 or 5 comprises the steps of: S1, introducing nitrile-containing wastewater into the device body (1), turning on the power supply (6), and keeping the micro-nano bubble generator (8) closed; S2, turning off the power supply (6), and the micro-nano bubble generator (8) starts to operate; S3, closing the micro-nano bubble generator (8) and allowing the mixture to settle.

7. The nitrile-containing wastewater pretreatment process according to claim 6, wherein: In step S1, the current density on the anode (4) and the cathode (5) is controlled to be 7-15 mA / cm 2 .

8. The nitrile-containing wastewater pretreatment process according to claim 6, wherein: In step S2, the particle size of the micro-nano bubbles generated by the micro-nano bubble generator (8) is 50 to 100 μm.

9. The nitrile-containing wastewater pretreatment process according to claim 6, wherein: In step S3, the time of static precipitation is ≥5 min.

10. The nitrile-containing wastewater pretreatment process according to any one of claims 7 to 9, characterized in that: The hydraulic retention time is controlled at 7 to 8 hours, the pH value is controlled at 7.2 to 7.8 during operation, and the operating temperature is controlled at 26 to 30°C.

Images