Coking wastewater co-treatment method based on MBR (Membrane Bioreactor) technology

Abstract

The invention relates to the field of environmental engineering and technology, and discloses a coprocessing method for coking wastewater based on MBR (membrane bioreactor) technology, which sequentially comprises the steps of pretreatment, biological enhancement treatment, nitrogen and phosphorus removal treatment, sludge regulation and control treatment, membrane pollution control treatment and circular treatment, and comprises the following steps: introducing coking wastewater into a grating and a grit chamber; performing pretreatment to remove large-particle impurities; in the biological enhancement and nitrogen and phosphorus removal stage, a microbial agent is added to regulate and control the reaction environment so as to improve the pollutant degradation efficiency; accurate management and control of sludge performance and membrane pollution are realized by using an online monitoring technology; finally, sludge, cleaning wastewater and the like generated in all links are collected in a classified mode, the sludge is subjected to resource utilization after stabilization treatment, the cleaning wastewater is reused in the pretreatment stage, and a closed-loop treatment system is formed; through the steps, the problems of incomplete removal of COD (Chemical Oxygen Demand) and ammonia nitrogen, low removal rate of total nitrogen and total phosphorus, sludge bulking, fast membrane pollution and high risk of secondary pollution in the traditional process are effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of environmental engineering and technology, and in particular to a coking wastewater collaborative treatment method based on MBR technology. Background Art

[0002] Coking plant wastewater is a complex and difficult-to-degrade industrial wastewater. It contains large amounts of recalcitrant organic compounds such as phenols, benzene series, and polycyclic aromatic hydrocarbons (PAHs). It is also highly toxic and high in salinity. Traditional activated sludge or biological treatment processes have poor microbial adaptability when treating this type of wastewater, resulting in incomplete COD and ammonia nitrogen removal and low treatment efficiency. Furthermore, due to the high ammonia nitrogen concentration in coking plant wastewater, traditional processes such as the A / O and SBR processes have limited effectiveness in removing total nitrogen and total phosphorus, making it difficult to meet increasingly stringent emission standards. During treatment, suspended solids and biological metabolites in coking plant wastewater can easily lead to sludge bulking or aging, resulting in poor sludge settling performance and high treatment costs. Furthermore, the large amounts of colloids, suspended solids, and dissolved organic matter in the wastewater easily form a fouling layer on the membrane surface, causing a rapid decrease in membrane flux, requiring frequent cleaning, and shortening membrane life. Furthermore, the excess sludge and spent membranes generated by traditional treatment processes contain heavy metals and toxic substances, which can easily cause secondary pollution if improperly handled. Therefore, it is of great practical significance to develop an efficient coking wastewater treatment technology to solve the above problems. Summary of the Invention

[0003] (1) Technical problems solved

[0004] In response to the shortcomings of the existing technology, the present invention provides a co-treatment method for coking wastewater based on MBR technology, which has the advantages of efficiently degrading refractory organic matter, improving nitrogen and phosphorus removal rates, and effectively alleviating sludge swelling and membrane fouling. It solves the problems of incomplete COD and ammonia nitrogen removal, limited total nitrogen and total phosphorus removal effects, poor sludge settling performance, rapid membrane flux decline, and high risk of secondary pollution in traditional treatment processes.

[0005] (2) Technical solution

[0006] To achieve the above object, the present invention provides the following technical solution: a method for coking wastewater collaborative treatment based on MBR technology, comprising the following steps:

[0007] Step 1: Pretreatment: Coking wastewater is introduced into the screen and grit chamber. Large suspended solids and impurities at the bottom of the chamber are removed through pretreatment methods such as coagulation sedimentation, mechanical filtration, and centrifugal dehydration. The sludge removal rate Rz is monitored in real time to adjust the operating parameters.

[0008] Step 2: Bio-augmented treatment: The pre-treated wastewater is fed into the MBR reaction tank, where high-efficiency degradation agents are added and an appropriate dissolved oxygen concentration is maintained. The dosage of the agents and the aeration intensity are adjusted by real-time monitoring of the COD degradation rate Cy.

[0009] Step 3: Denitrification and phosphorus removal: Create an anoxic-aerobic alternating environment in the MBR reactor to achieve denitrification and phosphorus removal through the metabolic action of phosphate-accumulating bacteria and denitrifying bacteria. Set the calculation formula for the total nitrogen removal rate Ns and the total phosphorus removal rate Ps, and adjust the time allocation of the anoxic and aerobic stages based on the monitoring data.

[0010] Step 4: Sludge control and treatment: Install an online sludge concentration monitor in the MBR system to adjust the sludge return ratio and sludge discharge volume in real time according to the calculated value of the sludge volume index Fu. When the sludge volume index Fu value exceeds the warning range, timely adjust the strategy;

[0011] Step 5: Membrane fouling control: An online monitoring device for membrane pressure difference is installed in the MBR system. When the membrane pressure difference reaches the threshold, the chemical cleaning program is automatically started, and the chemical concentration and cleaning cycle are adjusted according to the membrane flux attenuation rate Tv.

[0012] Step 6. Circular treatment: The sludge, cleaning wastewater, backwash wastewater and residual sludge generated in the above steps are collected and processed separately. The sludge is recycled after stabilization treatment, and the cleaning wastewater is returned to the pretreatment stage to form a closed-loop treatment.

[0013] Preferably, the pretreatment process in step 1 is:

[0014] S1.1. Coking wastewater is introduced into the screen and grit chamber. By adding 2.5% to 5% of the wastewater volume of coagulant and 0.3% to 0.6% of coagulant aid, the suspended solids and some colloidal substances in the wastewater are condensed into large particles larger than 50 microns.

[0015] S1.2. Then, through a combination of three mechanical methods, fine screens, cyclone grit chambers, and gravity sedimentation, large suspended solids and bottom impurities are filtered out through the fine screens and cyclone grit chambers, and grit is removed through gravity sedimentation.

[0016] S1.3. Finally, a centrifugal dehydrator is used to treat the generated sludge. By setting the calculation formula of the sludge removal rate Rz and monitoring the data during the pretreatment process in real time, the dosage of coagulant and coagulant aid can be adjusted in time to optimize the operating parameters of the centrifugal dehydrator.

[0017] Preferably, the calculation formula for the sludge removal rate Rz in S1.3 is:

[0018]

[0019] In the formula, Rz represents the sludge removal rate, E 前 Indicates the amount of sludge before pretreatment, E 后 Indicates the amount of sludge after pretreatment.

[0020] Preferably, the bioaugmentation process in step 2:

[0021] S2.1. The pretreated wastewater is fed into the MBR reaction tank, where a high-efficiency biodegradation agent targeting refractory organic matter is added, and the dissolved oxygen concentration is maintained through an aeration system.

[0022] S2.2. Set the COD degradation rate Cy calculation formula, use the formula to monitor the online COD monitoring data in real time, and adjust the bacterial agent dosage and aeration intensity according to the changes in degradation rate.

[0023] Preferably, the calculation formula for the sludge removal rate Cy in S2.2 is:

[0024]

[0025] In the formula, Cy represents the COD degradation rate, A 前 represents the COD concentration before bioaugmentation treatment, A 后 Indicates the COD concentration after bioaugmentation treatment.

[0026] Preferably, the denitrification and phosphorus removal process in step three is:

[0027] S3.1. Create an anoxic-aerobic alternating environment in the MBR reactor to remove nitrogen and phosphorus by utilizing the metabolic effects of phosphate-accumulating bacteria and denitrifying bacteria.

[0028] S3.2. Set the calculation formula for the total nitrogen removal rate Ns and the total phosphorus removal rate Ps, and monitor the online total nitrogen and total phosphorus monitoring data in real time based on the calculated values ​​by adjusting the time allocation of the anoxic and aerobic stages.

[0029] Preferably, the calculation formula for the total nitrogen removal rate Ns in S3.2 is:

[0030]

[0031] In the formula, Ns represents the total nitrogen removal rate, B 前 represents the total nitrogen concentration before denitrification and phosphorus removal treatment, B 后 It indicates the total nitrogen concentration after denitrification and phosphorus removal treatment;

[0032] The calculation formula for the total phosphorus removal rate Ps in S3.2 is:

[0033]

[0034] In the formula, Ps represents the total phosphorus removal rate, C 前 represents the total phosphorus concentration before denitrification and phosphorus removal treatment, C 后 It indicates the total phosphorus concentration after denitrification and phosphorus removal treatment.

[0035] Preferably, the sludge regulation and treatment process in step 4 is:

[0036] S4.1. Install an online sludge concentration monitor in the MBR system and adjust the sludge return ratio and sludge discharge volume in real time based on the monitoring data;

[0037] S4.2. Set the calculation formula for the sludge volume index Fu and use the calculation results to monitor the online sludge volume in real time. When the sludge volume exceeds the pre-set warning range of the MBR, adjust the sludge return and discharge strategies in time.

[0038] Preferably, the calculation formula of the sludge volume index Fu in S4.2 is:

[0039]

[0040] In the formula, Fu represents the sludge volume index, R represents the sludge volume after 30 minutes of sedimentation (mL), and I represents the suspended solids concentration of the mixed liquor.

[0041] Preferably, the membrane fouling control treatment process in step 5 is:

[0042] S5.1. Install an online monitoring device for membrane pressure difference in the MBR system. When the membrane pressure difference reaches the set threshold, the chemical cleaning program will be automatically started.

[0043] S5.2. Set the calculation formula for the membrane flux attenuation rate Tv, use the calculation results to monitor the online membrane flux data in real time, and adjust the chemical cleaning agent concentration and cleaning cycle according to the membrane flux attenuation rate Tv;

[0044] The calculation formula of the membrane flux attenuation rate Tv in S5.2 is:

[0045]

[0046] In the formula, Tv represents the membrane flux attenuation rate, G0 represents the initial membrane flux, and G t Indicates the current membrane flux.

[0047] Compared with the existing technology, the present invention provides a co-treatment method for coking wastewater based on MBR technology, which has the following beneficial effects:

[0048] 1. The present invention achieves efficient removal of large suspended solids and bottom impurities by setting a grid and a grit chamber in combination with coagulation sedimentation, mechanical filtration and centrifugal dehydration, and real-time monitoring of sludge removal rate optimization parameters, which helps reduce equipment wear and operating costs, and provides high-quality water for subsequent biochemical treatment.

[0049] 2. The present invention adds high-efficiency degradation bacteria into the MBR reaction tank, monitors the COD degradation rate in real time to adjust the bacteria dosage and aeration intensity, and constructs an anoxic-aerobic alternating environment. The time allocation is adjusted according to the total nitrogen and total phosphorus removal rates, thereby achieving efficient degradation of difficult-to-degrade organic matter, greatly improving the denitrification and phosphorus removal efficiency, and making the COD, ammonia nitrogen, total nitrogen and total phosphorus removal effects significantly better than the beneficial effects of traditional processes.

[0050] 3. The present invention installs an online sludge concentration monitor and an online membrane pressure difference monitoring device to adjust the sludge return ratio, sludge discharge volume, chemical cleaning agent concentration and cleaning cycle in real time according to the sludge volume index and membrane flux attenuation rate, thereby effectively alleviating sludge swelling, reducing membrane flux attenuation rate, and reducing membrane pollution. At the same time, various types of wastewater and sludge are classified and treated for recycling, reducing the risk of secondary pollution and improving resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0053] See also Figure 1 A co-treatment method for coking wastewater based on MBR technology comprises the following steps:

[0054] Step 1: Pretreatment: Coking wastewater is introduced into the screen and grit chamber. Large suspended solids and impurities at the bottom of the chamber are removed through pretreatment methods such as coagulation sedimentation, mechanical filtration, and centrifugal dehydration. The sludge removal rate (Rz) is monitored in real time to adjust operating parameters to ensure good pretreatment results and provide guarantees for subsequent treatment processes.

[0055] Step 2: Bio-augmented treatment: The pretreated wastewater is fed into the MBR reaction tank, where high-efficiency degradation bacteria are added and an appropriate dissolved oxygen concentration is maintained. The COD degradation rate Cy is monitored in real time to adjust the amount of bacteria added and the aeration intensity to degrade refractory organic matter.

[0056] Step 3: Denitrification and phosphorus removal: Create an anoxic-aerobic alternating environment in the MBR reactor to achieve denitrification and phosphorus removal through the metabolic action of phosphate-accumulating bacteria and denitrifying bacteria. Set the calculation formula for the total nitrogen removal rate Ns and the total phosphorus removal rate Ps, and adjust the time allocation of the anoxic and aerobic stages based on monitoring data to improve the removal rate.

[0057] Step 4: Sludge control and treatment: Install an online sludge concentration monitor in the MBR system to adjust the sludge return ratio and sludge discharge volume in real time according to the calculated value of the sludge volume index Fu. When the sludge volume index Fu value exceeds the warning range, timely adjust the strategy to effectively alleviate sludge bulking;

[0058] Step 5: Membrane fouling control and treatment: An online membrane pressure differential monitoring device is installed in the MBR system. When the membrane pressure differential reaches the threshold, the chemical cleaning program is automatically started, and the chemical concentration and cleaning cycle are adjusted according to the membrane flux attenuation rate Tv, effectively solving the membrane fouling problem.

[0059] Step 6. Circular treatment: The sludge, cleaning wastewater, backwash wastewater and residual sludge generated in the above steps are collected and processed separately. The sludge is recycled after stabilization treatment, and the cleaning wastewater is returned to the pretreatment stage to form a closed-loop treatment to reduce the risk of secondary pollution and improve resource utilization.

[0060] The advantages are: the present invention solves the problems of incomplete COD and ammonia nitrogen removal, low total nitrogen and total phosphorus removal rate, sludge swelling, rapid membrane pollution, and high risk of secondary pollution in traditional processes through a coordinated strategy of pretreatment optimization, bioaugmentation, dynamic regulation of denitrification and phosphorus removal, intelligent sludge control, precise management of membrane pollution, and resource closed loop, thereby achieving efficient and stable treatment and resource recovery of coking wastewater.

[0061] Specifically, the preprocessing process in step 1 is:

[0062] S1.1, introduce the coking wastewater into the screen and grit chamber, add 2.5% to 5% of the wastewater volume of coagulant (for example, 1000m 3 Wastewater addition 25~50m 3 Coagulant solution) and 0.3% to 0.6% coagulant aid (e.g. 1000m 3 Wastewater addition 3~6m 3 Coagulant aid solution) to condense suspended solids and some colloidal substances in the wastewater into large particles larger than 50 microns, which are convenient for subsequent precipitation and removal;

[0063] S1.2. The three mechanical methods of fine screen, cyclone grit chamber and gravity sedimentation are combined to filter large suspended solids and impurities at the bottom of the pool through the fine screen and cyclone grit chamber, and then remove grit through gravity sedimentation. The combined process of fine screen (coarse filtration) → cyclone grit chamber (efficient sand removal) → gravity sedimentation (deep clarification) can achieve efficient removal of large suspended solids, grit and fine impurities in coking wastewater, with effluent SS ≤ 30 mg / L, providing high-quality water for subsequent biochemical treatment while reducing equipment wear and operating costs.

[0064] S1.3. Finally, a centrifugal dehydrator is used to treat the generated sludge. By setting the calculation formula for the sludge removal rate Rz and monitoring the data during the pretreatment process in real time, the dosage of coagulant and coagulant aid can be adjusted in time, and the operating parameters of the centrifugal dehydrator can be optimized, thereby effectively improving the pretreatment effect and ensuring the efficient operation of the subsequent treatment process.

[0065] Specifically, the calculation formula for the sludge removal rate Rz in S1.3 is:

[0066]

[0067] In the formula, Rz represents the sludge removal rate, E 前 Indicates the amount of sludge before pretreatment, E 后 Indicates the amount of sludge after pretreatment.

[0068] The advantages are: the present invention achieves efficient removal of large-particle suspended matter and impurities at the bottom of the pool by setting a grid and a grit chamber in combination with a pretreatment method of coagulation sedimentation, mechanical filtration and centrifugal dehydration, and real-time monitoring of the sludge removal rate optimization parameters, which helps to reduce equipment wear and operating costs, and provides the beneficial effect of high-quality water inlet for subsequent biochemical treatment.

[0069] Specifically, the bioaugmentation process in step 2:

[0070] S2.1. The pretreated wastewater is fed into the MBR reaction tank, where a high-efficiency biodegradation agent targeting refractory organic matter is added, and the dissolved oxygen concentration is maintained through an aeration system.

[0071] S2.2. Set the COD degradation rate Cy calculation formula, use the formula to monitor the online COD monitoring data in real time, and adjust the dosage of bacterial agent and aeration intensity according to the changes in degradation rate to efficiently degrade difficult-to-degrade organic matter.

[0072] Specifically, the calculation formula for the sludge removal rate Cy in S2.2 is:

[0073]

[0074] In the formula, Cy represents the COD degradation rate, A 前 represents the COD concentration before bioaugmentation treatment, A 后 Indicates the COD concentration after bioaugmentation treatment.

[0075] Specifically, the denitrification and phosphorus removal process in step 3:

[0076] S3.1. Create an anoxic-aerobic alternating environment in the MBR reactor to remove nitrogen and phosphorus by utilizing the metabolic effects of phosphate-accumulating bacteria and denitrifying bacteria.

[0077] S3.2. Set the calculation formula for the total nitrogen removal rate Ns and the total phosphorus removal rate Ps, monitor the online total nitrogen and total phosphorus monitoring data in real time based on the calculated values, and improve the nitrogen and phosphorus removal rates by adjusting the time allocation of the anoxic and aerobic stages.

[0078] Specifically, the calculation formula for the total nitrogen removal rate Ns in S3.2 is:

[0079]

[0080] In the formula, Ns represents the total nitrogen removal rate, B 前 represents the total nitrogen concentration before denitrification and phosphorus removal treatment, B 后 It indicates the total nitrogen concentration after denitrification and phosphorus removal treatment;

[0081] The calculation formula for total phosphorus removal rate Ps in S3.2 is:

[0082]

[0083] In the formula, Ps represents the total phosphorus removal rate, C 前 represents the total phosphorus concentration before denitrification and phosphorus removal treatment, C 后 It indicates the total phosphorus concentration after denitrification and phosphorus removal treatment.

[0084] The advantages are: the present invention adds high-efficiency degradation bacteria agents in the MBR reaction tank, monitors the COD degradation rate in real time to adjust the bacteria agent dosage and aeration intensity, and constructs an anaerobic-aerobic alternating environment, and adjusts the time allocation according to the total nitrogen and total phosphorus removal rates, thereby achieving high-efficiency degradation of difficult-to-degrade organic matter, greatly improving the denitrification and phosphorus removal efficiency, and making the COD, ammonia nitrogen, total nitrogen and total phosphorus removal effects significantly better than the beneficial effects of traditional processes.

[0085] Specifically, the sludge regulation and treatment process in step 4:

[0086] S4.1. Install an online sludge concentration monitor in the MBR system and adjust the sludge return ratio and sludge discharge volume in real time based on the monitoring data;

[0087] S4.2. Set the calculation formula for the sludge volume index Fu and use the calculation results to monitor the online sludge volume in real time. When the sludge volume exceeds the pre-set warning range of the MBR, adjust the sludge return and discharge strategies in time to effectively alleviate sludge bulking.

[0088] Specifically, the calculation formula for the sludge volume index Fu in S4.2 is:

[0089]

[0090] In the formula, Fu represents the sludge volume index, R represents the sludge volume after 30 minutes of sedimentation (mL), and I represents the suspended solids concentration of the mixed liquor.

[0091] Specifically, the membrane fouling control treatment process in step 5:

[0092] S5.1. Install an online monitoring device for membrane pressure difference in the MBR system. When the membrane pressure difference reaches the set threshold, the chemical cleaning program will be automatically started.

[0093] S5.2. Set the calculation formula for membrane flux attenuation rate Tv, use the calculation results to monitor online membrane flux data in real time, and adjust the chemical cleaning agent concentration and cleaning cycle according to the membrane flux attenuation rate Tv to effectively solve the problem of membrane fouling;

[0094] Specifically, the calculation formula for the membrane flux attenuation rate Tv in S5.2 is:

[0095]

[0096] In the formula, Tv represents the membrane flux attenuation rate, G0 represents the initial membrane flux, and G t Indicates the current membrane flux.

[0097] The advantages are: the present invention installs an online sludge concentration monitor and an online membrane pressure difference monitoring device, and adjusts the sludge return ratio, sludge discharge volume, chemical cleaning agent concentration and cleaning cycle in real time according to the sludge volume index and membrane flux attenuation rate, thereby effectively alleviating sludge swelling, reducing membrane flux attenuation rate, and reducing membrane pollution. At the same time, various types of wastewater and sludge are classified and treated for recycling, reducing the risk of secondary pollution, and improving resource utilization.

[0098] Example 1 and Example 2 (Using the Co-treatment Method of Coking Wastewater of the Present Invention)

[0099] Example 1

[0100] (1) The various indicators of the initial coking wastewater test are: COD concentration of 1500 mg / L, ammonia nitrogen concentration of 200 mg / L, total nitrogen concentration of 250 mg / L, and total phosphorus concentration of 10 mg / L;

[0101] (2) The treatment process is as follows: the treatment is carried out according to steps 1 to 6 of the present invention, including pretreatment, bioaugmentation treatment, denitrification and phosphorus removal treatment, sludge regulation treatment, membrane fouling control treatment and circulation treatment;

[0102] The specific parameters are set as follows:

[0103] Step 1: The dosage of coagulant is 3% of the wastewater volume, and the dosage of coagulant aid is 0.5% of the wastewater volume;

[0104] Step 2: Maintain the dissolved oxygen concentration at 2.5 mg / L, and adjust the dosage of the inoculant dynamically according to the COD degradation rate;

[0105] Step 3: The anoxic phase lasts 4 hours, and the aerobic phase lasts 8 hours. The time allocation is adjusted according to the total nitrogen and total phosphorus removal rates.

[0106] Step 4: The sludge return ratio is 50%, and the sludge discharge volume is dynamically adjusted according to the sludge volume index;

[0107] Step 5: The membrane pressure difference threshold is set to 0.05 MPa, and the cleaning cycle is dynamically adjusted according to the membrane flux attenuation rate.

[0108] Example 2

[0109] (1) The various indicators of the initial coking wastewater test are: COD concentration of 1800 mg / L, ammonia nitrogen concentration of 220 mg / L, total nitrogen concentration of 280 mg / L, and total phosphorus concentration of 12 mg / L;

[0110] (2) Processing flow: Same as in Example 1, processing is performed according to steps 1 to 6 of the present invention;

[0111] (3) Parameter settings are:

[0112] Step 1: The dosage of coagulant is 4% of the wastewater volume, and the dosage of coagulant aid is 0.6% of the wastewater volume;

[0113] Step 2: Maintain the dissolved oxygen concentration at 3.0 mg / L, and adjust the dosage of the inoculant dynamically according to the COD degradation rate;

[0114] Step 3: The anoxic phase lasts for 5 hours and the aerobic phase lasts for 7 hours. The time allocation is adjusted according to the total nitrogen and total phosphorus removal rates.

[0115] Step 4: The sludge return ratio is 60%, and the sludge discharge volume is dynamically adjusted according to the sludge volume index;

[0116] Step 5: The membrane pressure difference threshold is set to 0.06 mPa, and the cleaning cycle is dynamically adjusted according to the membrane flux attenuation rate.

[0117] Comparative Example 1 and Comparative Example 2 (using traditional processing method)

[0118] Comparative Example 1

[0119] (1) Wastewater characteristics: Same as Example 1, COD concentration is 1500 mg / L, ammonia nitrogen concentration is 200 mg / L, total nitrogen concentration is 250 mg / L, and total phosphorus concentration is 10 mg / L;

[0120] (2) Treatment method: traditional activated sludge process, no MBR technology, no online monitoring of sludge concentration and membrane fouling control;

[0121] (3) Parameter settings are:

[0122] Step 1: Treatment only through coagulation sedimentation and ordinary aeration tank, without dynamic adjustment mechanism

[0123] Step 2: No dynamic adjustment of sludge return ratio and sludge discharge volume;

[0124] Step 3: No membrane pollution control measures.

[0125] Comparative Example 2

[0126] (1) Wastewater characteristics: Same as Example 2, COD concentration is 1800 mg / L, ammonia nitrogen concentration is 220 mg / L, total nitrogen concentration is 280 mg / L, and total phosphorus concentration is 12 mg / L;

[0127] (2) Treatment method: traditional biological filter method, no MBR technology, no online monitoring of sludge concentration and membrane fouling control;

[0128] (3) Parameter settings are:

[0129] Step 1: Treatment is performed only through biological filters, without a dynamic adjustment mechanism;

[0130] Step 2: No dynamic adjustment of sludge return ratio and sludge discharge volume;

[0131] Step 3: No membrane pollution control measures.

[0132] Test results (Table 1)

[0133]

[0134] It can be seen from Table 1 that the co-treatment method of coking wastewater of the present invention (Example 1 and Example 2) is significantly better than the traditional treatment method (Comparative Example 1 and Comparative Example 2) in the removal of COD, ammonia nitrogen, total nitrogen and total phosphorus. At the same time, the sludge settling performance is better, the membrane flux attenuation rate is lower, and the risk of secondary pollution is also lower, which shows that the treatment method of the present invention has advantages in improving treatment efficiency and reducing operating costs.

[0135] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A co-treatment method for coking wastewater based on MBR technology, characterized in that: The following steps are involved: Step 1: Pretreatment: Coking wastewater is introduced into the screen and grit chamber. Large suspended solids and impurities at the bottom of the chamber are removed through pretreatment methods such as coagulation sedimentation, mechanical filtration, and centrifugal dehydration. The sludge removal rate Rz is monitored in real time to adjust the operating parameters. Step 2: Bio-augmented treatment: The pre-treated wastewater is fed into the MBR reaction tank, where high-efficiency degradation agents are added and an appropriate dissolved oxygen concentration is maintained. The dosage of the agents and the aeration intensity are adjusted by real-time monitoring of the COD degradation rate Cy. Step 3: Denitrification and phosphorus removal: Create an anoxic-aerobic alternating environment in the MBR reactor to achieve denitrification and phosphorus removal through the metabolic action of phosphate-accumulating bacteria and denitrifying bacteria. Set the calculation formula for the total nitrogen removal rate Ns and the total phosphorus removal rate Ps, and adjust the time allocation of the anoxic and aerobic stages based on the monitoring data. Step 4: Sludge control and treatment: Install an online sludge concentration monitor in the MBR system to adjust the sludge return ratio and sludge discharge volume in real time according to the calculated value of the sludge volume index Fu. When the sludge volume index Fu value exceeds the warning range, timely adjust the strategy; Step 5: Membrane fouling control: An online monitoring device for membrane pressure difference is installed in the MBR system. When the membrane pressure difference reaches the threshold, the chemical cleaning program is automatically started, and the chemical concentration and cleaning cycle are adjusted according to the membrane flux attenuation rate Tv. Step 6. Circular treatment: The sludge, cleaning wastewater, backwash wastewater and residual sludge generated in the above steps are collected and processed separately. The sludge is recycled after stabilization treatment, and the cleaning wastewater is returned to the pretreatment stage to form a closed-loop treatment.

2. The method for coking wastewater collaborative treatment based on MBR technology according to claim 1, characterized in that: The pretreatment process in step 1 is: S1.

1. Coking wastewater is introduced into the screen and grit chamber. By adding 2.5% to 5% of the wastewater volume of coagulant and 0.3% to 0.6% of coagulant aid, the suspended solids and some colloidal substances in the wastewater are condensed into large particles larger than 50 microns. S1.

2. Then, through a combination of three mechanical methods, fine screens, cyclone grit chambers, and gravity sedimentation, large suspended solids and bottom impurities are filtered out through the fine screens and cyclone grit chambers, and grit is removed through gravity sedimentation. S1.

3. Finally, a centrifugal dehydrator is used to treat the generated sludge. By setting the calculation formula of the sludge removal rate Rz and monitoring the data during the pretreatment process in real time, the dosage of coagulant and coagulant aid can be adjusted in time to optimize the operating parameters of the centrifugal dehydrator.

3. The method for coking wastewater collaborative treatment based on MBR technology according to claim 2, characterized in that: The calculation formula for the sludge removal rate Rz in S1.3 is: In the formula, Rz represents the sludge removal rate, E 前 Indicates the amount of sludge before pretreatment, E 后 Indicates the amount of sludge after pretreatment.

4. The method for coking wastewater collaborative treatment based on MBR technology according to claim 1, characterized in that: The bioaugmentation process in step 2: S2.

1. The pretreated wastewater is fed into the MBR reaction tank, where a high-efficiency biodegradation agent targeting refractory organic matter is added, and the dissolved oxygen concentration is maintained through an aeration system. S2.

2. Set the COD degradation rate Cy calculation formula, use the formula to monitor the online COD monitoring data in real time, and adjust the bacterial agent dosage and aeration intensity according to the changes in degradation rate.

5. The method for co-processing co-processing wastewater based on MBR technology according to claim 4, characterized in that: The calculation formula for the sludge removal rate Cy in S2.2 is: In the formula, Cy represents the COD degradation rate, A 前 represents the COD concentration before bioaugmentation treatment, A 后 Indicates the COD concentration after bioaugmentation treatment.

6. The method for co-processing co-processing wastewater based on MBR technology according to claim 1, characterized in that: The denitrification and phosphorus removal process in step 3: S3.

1. Create an anoxic-aerobic alternating environment in the MBR reactor to remove nitrogen and phosphorus by utilizing the metabolic effects of phosphate-accumulating bacteria and denitrifying bacteria. S3.

2. Set the calculation formula for the total nitrogen removal rate Ns and the total phosphorus removal rate Ps, and monitor the online total nitrogen and total phosphorus monitoring data in real time based on the calculated values ​​by adjusting the time allocation of the anoxic and aerobic stages.

7. The method for co-processing co-processing wastewater based on MBR technology according to claim 6, characterized in that: The calculation formula for the total nitrogen removal rate Ns in S3.2 is: In the formula, Ns represents the total nitrogen removal rate, B 前 represents the total nitrogen concentration before denitrification and phosphorus removal treatment, B 后 It indicates the total nitrogen concentration after denitrification and phosphorus removal treatment; The calculation formula for the total phosphorus removal rate Ps in S3.2 is: In the formula, Ps represents the total phosphorus removal rate, C 前 represents the total phosphorus concentration before denitrification and phosphorus removal treatment, C 后 It indicates the total phosphorus concentration after denitrification and phosphorus removal treatment.

8. The method for coking wastewater collaborative treatment based on MBR technology according to claim 1, characterized in that: The sludge regulation and treatment process in step 4: S4.

1. Install an online sludge concentration monitor in the MBR system and adjust the sludge return ratio and sludge discharge volume in real time based on the monitoring data; S4.

2. Set the calculation formula for the sludge volume index Fu and use the calculation results to monitor the online sludge volume in real time. When the sludge volume exceeds the pre-set warning range of the MBR, adjust the sludge return and discharge strategies in time.

9. The method for coking wastewater collaborative treatment based on MBR technology according to claim 8, characterized in that: The calculation formula of the sludge volume index Fu in S4.2 is: In the formula, Fu represents the sludge volume index, R represents the sludge volume after 30 minutes of sedimentation (mL), and I represents the suspended solids concentration of the mixed liquor.

10. The method for coking wastewater collaborative treatment based on MBR technology according to claim 1, characterized in that: Membrane fouling control treatment process in step 5: S5.

1. Install an online monitoring device for membrane pressure difference in the MBR system. When the membrane pressure difference reaches the set threshold, the chemical cleaning program will be automatically started. S5.

2. Set the calculation formula for the membrane flux attenuation rate Tv, use the calculation results to monitor the online membrane flux data in real time, and adjust the chemical cleaning agent concentration and cleaning cycle according to the membrane flux attenuation rate Tv; The calculation formula of the membrane flux attenuation rate Tv in S5.2 is: In the formula, Tv represents the membrane flux attenuation rate, G0 represents the initial membrane flux, and G t Indicates the current membrane flux.

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