A biological treatment system and method for petroleum wastewater

Abstract

The present invention discloses a petroleum wastewater biological treatment system and method, which belongs to the technical field of petroleum wastewater treatment, and includes: a pretreatment device for removing large particles in petroleum wastewater and reducing the oil content; a microorganism input device for inputting microorganisms capable of degrading petroleum pollutants into a bioreactor; a bioreactor containing screened microorganisms for converting petroleum pollutants into harmless substances; an environmental condition control system and a bioenhancement and stimulation unit are arranged in the bioreactor; the environmental condition control system is used to adjust the temperature, pH value and oxygen supply in the bioreactor; the bioenhancement and stimulation unit is used to accelerate the degradation process of microorganisms; a post-treatment device is used to remove residual non-biodegradable substances; a monitoring and control center is used to monitor the treatment process and adjust the operating parameters. The present invention is used to solve the technical problem of low sewage treatment efficiency of the petroleum wastewater biological treatment system in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum wastewater treatment, and specifically relates to a petroleum wastewater biological treatment system and method. Background Art

[0002] Wastewater generated during the production and processing of the petroleum industry poses a serious threat to the environment. Petroleum wastewater contains a variety of harmful substances, including petroleum and petroleum derivatives, heavy metals, salts, and other organic and inorganic pollutants. If these pollutants are not treated or treated improperly, they will have long-term negative impacts on water bodies, soil and the atmosphere, endangering ecosystems and human health.

[0003] Traditional petroleum wastewater treatment technologies mainly rely on physical and chemical methods, such as sedimentation, flocculation, filtration, adsorption and chemical oxidation. These methods are effective in removing suspended solids and some soluble pollutants, but are less efficient in treating biodegradable organic matter and some persistent pollutants. In addition, secondary pollutants that may be generated during chemical treatment are also a challenge to environmental protection.

[0004] In recent years, biological treatment technology has attracted widespread attention due to its high cost-effectiveness, simple operation and environmental friendliness. Biological treatment uses the metabolic ability of microorganisms to convert organic pollutants into harmless or low-toxic substances, such as water and carbon dioxide. However, the efficiency of the biological treatment process is affected by many factors, including the type and activity of microorganisms, the supply of nutrients, environmental conditions, and the nature and concentration of pollutants. Therefore, it is necessary to develop an integrated biological treatment system for petroleum wastewater that can minimize the impact on the environment while ensuring treatment efficiency. Summary of the invention

[0005] In view of the above problems, the present invention provides a petroleum wastewater biological treatment system and method, which are used to solve the technical problem of low wastewater treatment efficiency of the petroleum wastewater biological treatment system in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A petroleum wastewater biological treatment system, comprising: Pretreatment units to remove large particles and reduce the oil content in petroleum wastewater; A microorganism input device, used for inputting microorganisms capable of degrading petroleum pollutants into the bioreactor; A bioreactor containing selected microorganisms for converting petroleum pollutants into harmless substances; an environmental condition control system and a bioaugmentation and stimulation unit are provided in the bioreactor; Environmental condition control systems to adjust temperature, pH, and oxygen supply in bioreactors; Bioaugmentation and stimulation units to accelerate the degradation process of microorganisms; Post-treatment device to remove residual non-biodegradable substances; Monitoring and control center to monitor the process and adjust operating parameters.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: the system removes large particles and reduces oil content through the pretreatment device, introduces degradation microorganisms through the microbial input device, accelerates the degradation process through the environmental condition control system and the bio-enhancement unit in the bioreactor, removes residual substances through the post-treatment device, and the monitoring and control center ensures the treatment efficiency. Such a system design improves the treatment efficiency and effect and ensures the effective purification of petroleum wastewater.

[0008] A method for a biological treatment system for petroleum wastewater, comprising: S1. Pretreatment: First, the petroleum wastewater needs to be pretreated to remove large particles and reduce the oil content to ensure the effectiveness of the subsequent biological treatment process; S2. Microorganism input device: select microorganisms capable of degrading petroleum pollutants and input them into the bioreactor; S3, bioreactor: add the selected microorganisms into the bioreactor; in the reactor, the microorganisms will convert the petroleum pollutants into harmless substances through their metabolic process, and obtain water and carbon dioxide; S31. Optimization of environmental conditions: Adjust the environmental conditions in the reactor to optimize the growth and metabolic activities of microorganisms.

[0009] S32. Bioaugmentation and stimulation: If the microbial degradation rate under natural conditions is slow, bioaugmentation and biostimulation methods can be used to accelerate the degradation process.

[0010] S4. Post-treatment: After biological treatment is completed, post-treatment such as sedimentation and filtration may be required to further remove residual non-biodegradable substances.

[0011] S5. Monitoring and control: Various indicators need to be monitored throughout the process to ensure the treatment effect and adjust operating parameters as needed.

[0012] Compared with the prior art, the invention has the following beneficial effects: the method includes pretreatment, microbial screening, bioreactor treatment, environmental condition optimization, bioaugmentation and stimulation, post-treatment and monitoring and control steps. This method can effectively convert petroleum pollutants into harmless substances, while optimizing the growth and metabolic activities of microorganisms, accelerating the degradation process, and ensuring the high efficiency and stability of the treatment process.

[0013] As a further improvement of the above scheme, a microbial detection device is added in step S3 to detect the reproduction of microorganisms. The device includes sensors and analysis software, and can collect data in real time and evaluate the reproduction and metabolic status of microorganisms. The specific steps include: S31. Microbial detection: Add a microbial detection device to the bioreactor to monitor the growth of microorganisms in real time; S32, data collection: The microbial detection device regularly collects the number of microorganisms ( ) and activity ( ) data; S33, threshold judgment: set the threshold of microbial quantity ( ), and the collected quantity ( ) and threshold ( ) for comparison; S34, Data Analysis: If ( ) reaches or exceeds ( ), the microorganisms are considered to reproduce normally and the current bioreactor operation continues; if ( ) has not reached ( ), then the following calculation is performed: , in,( ) represents the growth rate of microorganisms, ( ) indicates that in the time interval ( ) changes in the number of microorganisms, ( ) indicates the activity of microorganisms; S35. Adjustment measures: If the calculated reproduction rate ( ) is lower than the preset minimum reproduction rate ( ), then increase the supply of nutrients ( ) to the new amount ( ): , in,( ) is the new nutrient supply, ( ) is the current supply, ( ) is the adjustment factor, ( ) is the preset minimum reproduction rate, ( ) is the calculated reproduction rate, ( ) is the activity of microorganisms. New nutrients include nitrogen, phosphorus, potassium and trace elements.

[0014] The technical effect of the above improvement is: adding a microbial detection device to the bioreactor to monitor the growth of microorganisms in real time and adjust the supply of nutrients according to the data. This step can ensure the normal growth of microorganisms and improve the efficiency and stability of biological treatment.

[0015] As a further improvement of the above solution, when excess nutrients appear after new nutrients are added in step S315, the following steps are taken: S3151. Residual nutrient detection: Add a residual nutrient detection device to the bioreactor to detect the residual amount of nutrients after the reaction ( ); the bioreactors are arranged in a plurality; S3152, residual quantity analysis: Select the residual quantity ( ) minimum and remaining amount ( ) the largest bioreactor, and then neutralize the nutrients in the two bioreactors, and again perform detection by the remaining nutrient detection device; S3153. Treatment of residual nutrients: If it is confirmed that there are too many residual nutrients, add new petroleum wastewater to the bioreactor after neutralization for biological treatment; and adjust the subsequent nutrient supply according to the following formula ( ): , in,( ) is the nutrient supply for the next cycle, ( ) is the new supply of the current cycle, ( ) is the nutrient adjustment factor.

[0016] The technical effect of the above improvement is: when the newly added nutrients are in excess, they are detected and processed through the remaining nutrient detection device to avoid nutrient waste and possible environmental impact, while adjusting the subsequent nutrient supply to ensure the economy and environmental friendliness of the biological treatment system.

[0017] As a further improvement of the above solution, step S32 further includes the following steps: S321. The functional relationship for determining the microbial degradation rate is: , in,( ) represents the degradation rate, ( ) is the degradation rate constant, ( ) is the concentration of petroleum pollutants, ( ) is the nutrient concentration; S322, optimizing the degradation efficiency of microorganisms by controlling the concentration of nutrients within the range of (50-300 mg / L) and the concentration of petroleum pollutants within the range of (100-500 mg / L); S323, adding exogenous oil-reducing microorganisms into the reactor, the amount of which is (1%-5%) of the reactor volume; S324. Regularly add nutrients to the reactor to maintain the nutrient concentration within the optimized range. The frequency of addition is once every 24 hours.

[0018] The technical effect of the above improvement is: by controlling the concentration of nutrients and oil pollutants and regularly adding exogenous oil-reducing microorganisms and nutrients, the degradation efficiency of microorganisms is optimized. This step can significantly increase the degradation rate of oil pollutants and shorten the treatment time.

[0019] As a further improvement of the above solution, step S4 further includes: S41, setting the sedimentation time to ensure that the non-biodegradable substances can be effectively precipitated; S42, using a filtering device, its filtering efficiency ( )satisfy: , in,( }) is the filtration efficiency, ( ) is the filtering coefficient, ( ) is the filtering time, and ( }) in the range of (1h-3h); S43. For the residual non-biodegradable substances, adsorbents are used for adsorption treatment.

[0020] The technical effect of the above improvement is: by setting the sedimentation time and using filtering devices and adsorbents to treat the residual non-biodegradable substances, it is ensured that the treated water quality meets the discharge standards, thereby improving the reliability of the treatment system and the environmental protection effect.

[0021] As a further improvement of the above solution, step S5 further includes: S51. Setting monitoring parameters, including but not limited to temperature, pH value, oxygen concentration, concentration of non-biodegradable substances, and microbial activity indicators; S52. Use a real-time monitoring system whose monitoring frequency meets the following requirements: , in,( ) is the monitoring frequency, ( ) is the monitoring time interval, and ( ) is within the range of (0.5h-2h); S53. According to the monitoring results, adjust the operating parameters, including but not limited to the reactor temperature, pH value, and oxygen supply, to optimize the treatment effect; S54, using a feedback control algorithm, its control function ( )for: , in,( ),( ),( ) are proportional, integral and differential control coefficients respectively, ( ) is the target parameter value, ( ) is the actual monitoring parameter value, ( ) are variables for adjusting and controlling the process.

[0022] The technical effect of the above improvement is: by setting monitoring parameters and adopting a real-time monitoring system, and adjusting operating parameters using a feedback control algorithm, the optimization of the entire treatment process is ensured. This step can achieve precise control of the treatment process, improve the system's automation level and treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the biological treatment system of petroleum wastewater in the present invention.

[0024] Figure 2 It is a schematic diagram of the method of the petroleum wastewater biological treatment system in the present invention.

[0025] Figure 3 This is a schematic diagram of the process after adding a microbial detection device in the present invention.

[0026] Figure 4 This is a schematic diagram of the situation in which excess nutrients occur after new nutrients are added in the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution, the present invention is described in detail below in conjunction with embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0028] like Figure 1 As shown, the specific scheme of this embodiment is: a petroleum wastewater biological treatment system, including: Pretreatment units to remove large particles and reduce the oil content in petroleum wastewater; A microorganism input device, used for inputting microorganisms capable of degrading petroleum pollutants into the bioreactor; A bioreactor containing selected microorganisms for converting petroleum pollutants into harmless substances; an environmental condition control system and a bioaugmentation and stimulation unit are provided in the bioreactor; Environmental condition control systems to adjust temperature, pH, and oxygen supply in bioreactors; Bioaugmentation and stimulation units to accelerate the degradation process of microorganisms; Post-treatment device to remove residual non-biodegradable substances; Monitoring and control center to monitor the process and adjust operating parameters.

[0029] like Figure 2 As shown, a method of a petroleum wastewater biological treatment system comprises: S1. Pretreatment: First, the petroleum wastewater needs to be pretreated to remove large particles and reduce the oil content to ensure the effectiveness of the subsequent biological treatment process; S2. Microbial input device: Select microorganisms that can degrade petroleum pollutants and input them into the bioreactor.

[0030] S3, bioreactor: add the selected microorganisms into the bioreactor; in the reactor, the microorganisms will convert the petroleum pollutants into harmless substances through their metabolic process, and obtain water and carbon dioxide; S31. Optimization of environmental conditions: Adjust the environmental conditions in the reactor to optimize the growth and metabolic activities of microorganisms.

[0031] S32. Bioaugmentation and stimulation: If the microbial degradation rate under natural conditions is slow, bioaugmentation and biostimulation methods can be used to accelerate the degradation process.

[0032] S4. Post-treatment: After biological treatment is completed, post-treatment such as sedimentation and filtration may be required to further remove residual non-biodegradable substances.

[0033] S5. Monitoring and control: Various indicators need to be monitored throughout the process to ensure the treatment effect and adjust the operating parameters as needed. During the entire treatment process, the monitoring and control center will monitor key indicators such as temperature, pH value, oxygen concentration and oil content in real time.

[0034] like Figure 3 As shown, as a preferred embodiment of the above embodiment, a microorganism detection device is added in step S31 to detect the reproduction of microorganisms. It includes sensors and analysis software, which can collect data in real time and evaluate the reproduction and metabolic status of microorganisms. The specific steps include: S311. Microbial detection: Add a microbial detection device to the bioreactor to monitor the growth of microorganisms in real time; S312, data collection: The microbial detection device regularly collects the number of microorganisms ( ) and activity ( ) data; S313, threshold determination: setting the threshold of the number of microorganisms ( ), and the collected quantity ( ) and threshold ( ) for comparison; S314, Data Analysis: If ( ) reaches or exceeds ( ), the microorganisms are considered to reproduce normally and the current bioreactor operation continues; if ( ) has not reached ( ), then the following calculation is performed: , in,( ) represents the growth rate of microorganisms, ( ) indicates that in the time interval ( ) changes in the number of microorganisms, ( ) indicates the activity of microorganisms; S315, Adjustment measures: If the calculated reproduction rate ( ) is lower than the preset minimum reproduction rate ( ), then increase the supply of nutrients ( ) to the new amount ( ): , in,( ) is the new nutrient supply, ( ) is the current supply, ( ) is the adjustment factor, ( ) is the preset minimum reproduction rate, ( ) is the calculated reproduction rate, ( ) is the activity of microorganisms. New nutrients include nitrogen, phosphorus, potassium and trace elements.

[0035] Specifically, the following parameters are set: Changes in the number of microorganisms ( )=50 Time interval ( ) = 2 hours area( ) = 3 square meters Current nutrient supply ( ) = 150 units The preset minimum reproduction rate ( ) = 30 units / m2 / hour Adjustment factor( )=0.8First, Calculate the activity of microorganisms ( ):

[0036] Next, calculate the new nutrient supply ( ): , , , , =42 units Since the calculated reproduction rate ( ) is lower than the preset minimum reproduction rate ( ), the supply of nutrients needs to be reduced. According to the above calculation, the new supply of nutrients ( ) should be 42 units.

[0037] like Figure 4 As shown, as a preferred embodiment of the above embodiment, when excess nutrients occur after new nutrients are added in step S315, the following steps are taken: S3151. Residual nutrient detection: Add a residual nutrient detection device to the bioreactor to detect the residual amount of nutrients after the reaction ( ); the bioreactors are arranged in a plurality; S3152, residual quantity analysis: Select the residual quantity ( ) minimum and remaining amount ( ) the largest bioreactor, and then neutralize the nutrients in the two bioreactors, and again perform detection by the remaining nutrient detection device; S3153. Treatment of residual nutrients: If it is confirmed that there are too many residual nutrients, add new petroleum wastewater to the bioreactor after neutralization for biological treatment; and adjust the subsequent nutrient supply according to the following formula ( ): , in,( ) is the nutrient supply for the next cycle, ( ) is the new supply of the current cycle, ( ) is the nutrient adjustment factor.

[0038] First, there is the formula for calculating the amount of remaining nutrients: , Indicates the amount of remaining nutrients that need to be adjusted. is the amount of nutrients remaining detected, It is the preset maximum allowable remaining amount.

[0039] Let's implement this calculation process through a specific example: The following parameters are set: The amount of nutrients remaining detected ( ) = 200 units, the preset maximum allowable remaining quantity ( ) = 150 units, the new supply in the current cycle ( ) = 42 units (derived from the previous example), nutrient adjustment factor ( )=0.5, first, calculate the amount of remaining nutrients that need to be adjusted ( ):

[0040] Next, calculate the nutrient supply for the next cycle ( ): , , ,

[0041] According to the above calculation, the nutrient supply in the next cycle ( ) should be 17 units.

[0042] As a preferred embodiment of the above embodiment, step S32 further includes the following steps: S321. The functional relationship for determining the microbial degradation rate is: , in,( ) represents the degradation rate, ( ) is the degradation rate constant, ( ) is the concentration of petroleum pollutants, ( ) is the nutrient concentration; S322, optimizing the degradation efficiency of microorganisms by controlling the concentration of nutrients within the range of (50-300 mg / L) and the concentration of petroleum pollutants within the range of (100-500 mg / L); S323, adding exogenous oil-reducing microorganisms into the reactor, the amount of which is (1%-5%) of the reactor volume; S324. Regularly add nutrients to the reactor to maintain the nutrient concentration within the optimized range. The frequency of addition is once every 24 hours.

[0043] Specific numerical example: Set the degradation rate constant ( ) is 0.01L / mgh, the initial concentration of petroleum pollutants ( O) is 400 mg / L, and the initial concentration of nutrients ( ) is 200mg / L.

[0044] Based on the above equation, we can calculate the degradation rate (v): ,

[0045]

[0046] This means that under given conditions, 800 mg of petroleum pollutants can be degraded per liter of water per hour.

[0047] Embodiment 1:

[0048] Control the nutrient concentration at 200 mg / L.

[0049] The concentration of petroleum pollutants is maintained at 400 mg / L.

[0050] The reactor volume was 1000 L, and the amount of exogenous oil-reducing microorganisms added was 10 L (i.e., 1% of the reactor volume).

[0051] Nutrients were added to the reactor every 24 hours to maintain the nutrient concentration at 200 mg / L.

[0052] Embodiment 2:

[0053] Control the nutrient concentration at 300 mg / L.

[0054] The concentration of petroleum pollutants is maintained at 500 mg / L.

[0055] The reactor volume was 500 L, and the amount of exogenous oil-reducing microorganisms added was 25 L (ie, 5% of the reactor volume).

[0056] Nutrients were added to the reactor every 24 hours to maintain the nutrient concentration at 300 mg / L.

[0057] Embodiment three:

[0058] Control the nutrient concentration at 50 mg / L.

[0059] The concentration of petroleum pollutants is maintained at 100 mg / L.

[0060] The reactor volume was 2000 L, and the amount of exogenous oil-reducing microorganisms added was 40 L (i.e., 2% of the reactor volume).

[0061] Nutrients were added to the reactor every 24 hours to maintain the nutrient concentration at 50 mg / L.

[0062] The above examples provide specific operating parameters to optimize the degradation efficiency of microorganisms. These parameters can be adjusted according to actual conditions to achieve the best treatment effect.

[0063] As a preferred embodiment of the above embodiment, step S4 further includes: S41, setting a sedimentation time to ensure that non-biodegradable substances can be effectively precipitated; wherein is the sedimentation time and satisfies the following relationship: , in, is the effective volume of the sedimentation tank, is the precipitation rate; S42, using a filtering device, its filtering efficiency ( )satisfy: , in,( }) is the filtration efficiency, ( ) is the filtering coefficient, ( ) is the filtering time, and ( }) in the range of (1h-3h); S43. For the residual non-biodegradable substances, use adsorbent for adsorption treatment. Adsorption efficiency ( ) can be calculated by the following formula: , in,( ) is the adsorption efficiency, ( ) is the initial concentration of non-biodegradable substances, ( ) is the concentration at equilibrium.

[0064] Specifically, the following parameters are set: Effective volume of sedimentation tank ( ) = 500 cubic meters Sedimentation rate ( ) = 5 cubic meters / hour Filter coefficient ( ) = 0.1 / hour Filter time( ) = 2 hours Initial non-biodegradable substance concentration ( )=100mg / L The concentration at equilibrium ( )=10mg / L Based on these parameters, it can be calculated: Example of sedimentation time

[0065] Example of filtration efficiency

[0066] Example of adsorption efficiency .

[0067] As a preferred embodiment of the above embodiment, step S5 further includes: S51. Setting monitoring parameters, including but not limited to temperature, pH value, oxygen concentration, concentration of non-biodegradable substances, and microbial activity indicators; S52. Use a real-time monitoring system whose monitoring frequency meets the following requirements: , in,( ) is the monitoring frequency, ( ) is the monitoring time interval, and ( ) is within the range of (0.5h-2h); Among them, set 1, side

[0068] S53. According to the monitoring results, adjust the operating parameters, including but not limited to the reactor temperature, pH value, and oxygen supply, to optimize the treatment effect; S54, using a feedback control algorithm, its control function ( )for: , in,( ),( ),( ) are proportional, integral and differential control coefficients respectively, ( ) is the target parameter value, ( ) is the actual monitoring parameter value, ( ) are variables for adjusting and controlling the process.

[0069] Specifically, the following parameters are set: Target pH( )=7.0 The actual pH value monitored ( )=6.8 Proportional control coefficient ( )=0.5 Integral control coefficient ( )=0.1 Derivative control coefficient ( )=0.05 Monitoring interval ( ) = 1 hour Need to calculate the control function ( ) value, and then adjust the pH value based on this value. The calculation formula of the control function is:

[0070] In this example, the pH change is assumed to be constant within the monitoring time interval, so the differential term ( ) is zero. The integral term ( ) will be the change ( ) multiplied by time( ).

[0071] Now calculate the control function ( ) value: Calculate the proportional term ( ):

[0072] Calculate the integral term ( ): If the integral is calculated from the start of monitoring, then:

[0073] The derivative term is zero because the setpoint change is constant.

[0074] Adding these values ​​together, we obtain the control function ( ) value:

[0075] This means that in order to adjust the actual pH to the target pH, an increase of 0.12 units is required. In practice, this may mean adding an appropriate amount of alkaline to the reactor to raise the pH.

[0076] Embodiment 4: S1. Pretreatment device: The device includes a primary sedimentation tank and an oil-water separator. The size of the primary sedimentation tank is 5m x 3m x 2.5m, which is used to remove particles with a diameter greater than 5mm in the oil wastewater. The oil-water separator uses gravity separation technology to reduce the oil content to below 50mg / L.

[0077] S2. Microbial injection device: This device includes an automatic metering pump and a mixing tank. The flow rate of the automatic metering pump is 2L / min, which is used to accurately inject the selected degradation microorganisms into the bioreactor. The volume of the mixing tank is 500L, which is used to ensure that the microorganisms and sewage are fully mixed.

[0078] S3. Bioreactor: This reactor is a closed tank reactor with dimensions of 10m x 5m x 3m, which contains selected Pseudomonas microorganisms for converting petroleum pollutants into harmless substances.

[0079] S31, Environmental Condition Control System: The system includes a temperature sensor, a pH sensor, a dissolved oxygen sensor, and corresponding controllers. The temperature is controlled at 25°C, the pH value is controlled at 7.0, and the dissolved oxygen concentration is controlled at 6 mg / L.

[0080] S32, Bio-enhancement and stimulation unit: This unit includes a nutrient supply system and an ultrasonic stimulation device. The nutrient supply system adds nutrients once every 24 hours to maintain the nutrient concentration at 100 mg / L. The frequency of the ultrasonic stimulation device is 35kHz, which is used to accelerate the degradation process of microorganisms.

[0081] S4, post-treatment device: The device includes a secondary sedimentation tank and an activated carbon filter. The secondary sedimentation tank has a size of 5m x 3m x 2.5m and is used to remove non-biodegradable substances. The activated carbon filter has a size of 2m x 2m x 2m and is used to absorb residual organic matter.

[0082] S5. Monitoring and Control Center: This center is equipped with a computer control system for real-time monitoring of the processing process and adjusting operating parameters.

[0083] Embodiment five: S1. Pretreatment device: The device includes a cyclone sedimentation tank and a membrane separator. The cyclone sedimentation tank has a diameter of 2 meters and a height of 3 meters, and is used to remove particles with a diameter greater than 2 mm. The membrane separator has a membrane pore size of 0.1 micron, and is used to reduce the oil content to less than 30 mg / L.

[0084] S2. Microorganism injection device: This device includes a metering pump and a static mixer. The flow rate of the metering pump is 1L / min, which is used to accurately inject the selected degradation microorganisms into the bioreactor. The length of the static mixer is 2 meters, which is used to ensure that the microorganisms are fully mixed with the sewage.

[0085] S3. Bioreactor: This is a cylindrical reactor with a diameter of 3 meters and a height of 4 meters. It contains selected Bacillus microorganisms to convert petroleum pollutants into harmless substances.

[0086] S31, Environmental Condition Control System: The system includes a temperature controller, a pH controller and a dissolved oxygen controller. The temperature is controlled at 30°C, the pH value is controlled at 6.5, and the dissolved oxygen concentration is controlled at 8 mg / L.

[0087] S32, Bio-enhancement and stimulation unit: This unit includes a trace element supply system and a light stimulation device. The trace element supply system adds trace elements once every 24 hours to maintain the trace element concentration at 5mg / L. The light intensity of the light stimulation device is 5000lx, which is used to accelerate the degradation process of microorganisms.

[0088] S4, post-treatment device: The device includes a flocculation sedimentation tank and a sand filter. The flocculation sedimentation tank has a size of 3m × 2m × 2m and is used to remove non-biodegradable substances. The sand filter has a size of 1.5m × 1.5m × 1.5m and is used to remove residual suspended matter.

[0089] S5. Monitoring and Control Center: The center is equipped with an automated monitoring system for real-time monitoring of the treatment process and adjusting operating parameters.

[0090] Embodiment six: S1. Pretreatment device: The device includes a multi-stage screen and an electric flocculator. The apertures of the multi-stage screen are 3 mm, 1 mm and 0.5 mm, respectively, for removing particles of different sizes. The voltage of the electric flocculator is 10V, which is used to reduce the oil content to below 10mg / L.

[0091] S2. Microorganism injection device: This device includes a micro pump and a spray mixer. The flow rate of the micro pump is 0.5L / min, which is used to accurately inject the selected degradation microorganisms into the bioreactor. The nozzle diameter of the spray mixer is 0.1mm, which is used to ensure that the microorganisms are fully mixed with the sewage.

[0092] S3. Bioreactor: This reactor is a vertical reactor with a diameter of 2 meters and a height of 6 meters. It contains selected nitrifying bacteria and denitrifying bacteria to convert petroleum pollutants into harmless substances.

[0093] S31, Environmental Condition Control System: The system includes a temperature controller, a pH controller and a dissolved oxygen controller. The temperature is controlled at 20°C, the pH value is controlled at 7.5, and the dissolved oxygen concentration is controlled at 5 mg / L.

[0094] S32, Bio-enhancement and stimulation unit: This unit includes a nutrient supply system and a mechanical stirring device. The nutrient supply system adds nutrients once every 24 hours to maintain the nutrient concentration at 150mg / L. The mechanical stirring device has a rotation speed of 200rpm to accelerate the degradation process of microorganisms.

[0095] S4, post-treatment device: This device includes a rapid sedimentation tank and an ozone oxidizer. The rapid sedimentation tank has a size of 4m x 3m x 3m and is used to remove non-biodegradable substances. The ozone oxidizer has an ozone output of 5g / h and is used to oxidize residual organic matter.

[0096] S5. Monitoring and Control Center: The center is equipped with an intelligent monitoring system for real-time monitoring of the treatment process and adjusting operating parameters.

[0097] It should be noted that, in this article, the terms include, contain or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to illustrate the principle and implementation of the technical solution of the present invention. The above examples are only used to help understand the method of the present invention and its core idea. The above are only preferred implementations of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements, modifications or changes can be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A biological treatment system for petroleum wastewater, characterized in that: include: Pretreatment units to remove large particles and reduce the oil content in petroleum wastewater; A microorganism input device, used for inputting microorganisms capable of degrading petroleum pollutants into the bioreactor; A bioreactor containing selected microorganisms for converting petroleum pollutants into harmless substances; an environmental condition control system and a bioaugmentation and stimulation unit are provided in the bioreactor; Environmental condition control systems to adjust temperature, pH, and oxygen supply in bioreactors; Bioaugmentation and stimulation units to accelerate the degradation process of microorganisms; Post-treatment device to remove residual non-biodegradable substances; Monitoring and control center to monitor the process and adjust operating parameters.

2. A process for a biological treatment system for petroleum wastewater, characterized in that: include: S1. Pretreatment: First, the petroleum wastewater needs to be pretreated to remove large particles and reduce the oil content to ensure the effectiveness of the subsequent biological treatment process; S2. Microorganism input device: select microorganisms capable of degrading petroleum pollutants and input them into the bioreactor; S3, bioreactor: adding the selected microorganisms into the bioreactor; in the reactor, the microorganisms convert the petroleum pollutants into harmless substances through their metabolic processes, obtaining water and carbon dioxide; S31. Environmental conditions optimization: Adjust the environmental conditions in the reactor to optimize the growth and metabolic activities of microorganisms; S32. Bioaugmentation and stimulation: If the degradation rate of microorganisms under natural conditions is slow, bioaugmentation and biostimulation methods are used to accelerate the degradation process; S4. Post-treatment: After biological treatment is completed, post-treatment, sedimentation or filtration may be required to further remove residual non-biodegradable substances; S5. Monitoring and control: Various indicators need to be monitored throughout the process to ensure treatment effectiveness and adjust operating parameters.

3. The process of a biological treatment system for petroleum wastewater according to claim 2 is characterized in that: In step S31, a microbial detection device is added to detect the reproduction of microorganisms. The microbial detection device includes a sensor and analysis software, which can collect data in real time and evaluate the reproduction and metabolic status of microorganisms. The specific steps include: S311. Microbial detection: Add a microbial detection device to the bioreactor to monitor the growth of microorganisms in real time; S312, data collection: The microbial detection device regularly collects the number of microorganisms ( ) and activity ( ) data; S313, threshold determination: setting the threshold of the number of microorganisms ( ), and the collected quantity ( ) and threshold ( ) for comparison; S314, Data Analysis: If ( ) reaches or exceeds ( ), the microorganisms are considered to reproduce normally and the current bioreactor operation continues; if ( ) has not reached ( ), then the following calculation is performed: ， in,( ) represents the growth rate of microorganisms, ( ) indicates that in the time interval ( ) changes in the number of microorganisms in ( ) indicates the activity of microorganisms; S315, Adjustment measures: If the calculated reproduction rate ( ) is lower than the preset minimum reproduction rate ( ), then increase the supply of nutrients ( ) to the new amount ( ): ， in,( ) is the new nutrient supply, ( ) is the current supply, ( ) is the adjustment factor, ( ) is the preset minimum reproduction rate, ( ) is the calculated reproduction rate, ( ) is the activity of microorganisms; new nutrients include nitrogen, phosphorus, potassium and trace elements.

4. The process of a biological treatment system for petroleum wastewater according to claim 3 is characterized in that: When excess nutrients occur after new nutrients are added in step S315, the following steps are taken: S3151. Residual nutrient detection: Add a residual nutrient detection device to the bioreactor to detect the residual amount of nutrients after the reaction ( ); the bioreactors are arranged in a plurality; S3152, residual quantity analysis: Select the residual quantity ( ) minimum and remaining amount ( ) the largest bioreactor, and then neutralize the nutrients in the two bioreactors, and again perform detection by the remaining nutrient detection device; S3153, treatment of residual nutrients: when it is confirmed that there are a lot of residual nutrients, add new petroleum wastewater into the bioreactor after neutralization for biological treatment; The subsequent nutrient supply is adjusted according to the following formula ( ): ， in,( ) is the nutrient supply for the next cycle, ( ) is the new supply of the current cycle, ( ) is the nutrient adjustment factor.

5. The process of a biological treatment system for petroleum wastewater according to claim 2 is characterized in that: Step S32 further includes the following steps: S321. The functional relationship for determining the microbial degradation rate is: ， in,( ) represents the degradation rate, ( ) is the degradation rate constant, ( ) is the concentration of petroleum pollutants, ( ) is the nutrient concentration; S322, optimizing the degradation efficiency of microorganisms by controlling the concentration of nutrients within the range of (50-300 mg / L) and the concentration of petroleum pollutants within the range of (100-500 mg / L); S323, adding exogenous oil-reducing microorganisms into the reactor, the amount of which is (1%-5%) of the reactor volume; S324. Regularly add nutrients to the reactor to maintain the nutrient concentration within the optimized range. The frequency of addition is once every 24 hours.

6. The process of a biological treatment system for petroleum wastewater according to claim 2, characterized in that: The step S4 further comprises: S41, setting the sedimentation time to ensure that the non-biodegradable substances can be effectively precipitated; S42, using a filtering device, its filtering efficiency ( )satisfy: ， in,( }) is the filtration efficiency, ( ) is the filtering coefficient, ( ) is the filtering time, and ( }) in the range of (1h-3h); S43. For the residual non-biodegradable substances, adsorbents are used for adsorption treatment.

7. The process of a biological treatment system for petroleum wastewater according to claim 2 is characterized in that: The step S5 further comprises: S51. Setting monitoring parameters, including but not limited to temperature, pH value, oxygen concentration, concentration of non-biodegradable substances, and microbial activity indicators; S52, adopt real-time monitoring system; S53. According to the monitoring results, adjust the operating parameters, including but not limited to the reactor temperature, pH value, and oxygen supply, to optimize the treatment effect; S54, using a feedback control algorithm, its control function ( )for: ， in,( ),( ),( ) are proportional, integral and differential control coefficients respectively, ( ) is the target parameter value, ( ) is the actual monitoring parameter value, ( ) are variables for adjusting and controlling the process.

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