Integrated ozone catalytic backwashing siC ceramic membrane bioreactor and process method for treating hydrocarbon-containing wastewater

Abstract

The application relates to a SiC ceramic membrane biological reactor with integrated ozone catalytic backwashing and a process method for treating hydrocarbon-containing wastewater, and belongs to the field of wastewater treatment. The reactor main body is vertically arranged and sequentially comprises an aerobic reaction zone, an anoxic reaction zone and an anaerobic reaction zone from top to bottom. The anaerobic reaction zone is connected with a submerged gas collecting device at the top, the submerged gas collecting device is used for collecting methane generated in the anaerobic reaction zone, a plate type ceramic membrane is arranged in the aerobic reaction zone, the outer wall of the aerobic reaction zone is connected with the bottom of the anaerobic reaction zone through a pipeline to form an external circulation, the bottom of the anaerobic reaction zone is connected with a substrate barrel, the substrate barrel is filled with wastewater, a carbon source, nutrient salts and trace elements, and the wastewater is discharged from the water outlet of the plate type ceramic membrane after being treated by the anaerobic reaction zone, the anoxic reaction zone and the aerobic reaction zone. The application combines chemical repair and microbial repair, and the two complement each other, can solve the problem of high chemical treatment cost, and can make up for the low efficiency of biological treatment.

Description

TECHNICAL FIELD

[0001] The application relates to a SiC ceramic membrane biological reactor with integrated ozone catalytic backwashing and a process method for treating hydrocarbon-containing wastewater, in particular to an integrated vertical circulating flow membrane biological reactor using an ozone catalytic oxidation process to couple a silicon carbide ceramic membrane to efficiently degrade polycyclic aromatic hydrocarbons, which is of great significance to deep treatment of refractory wastewater, biological methane gas recovery and carbon emission reduction, and belongs to the technical field of wastewater treatment. BACKGROUND

[0002] Polycyclic aromatic hydrocarbons in multiple forms and widely distributed are harmful to all forms of life, as a stubborn hydrophobic pollutant, have carcinogenicity and accumulation, and seriously threaten human health and ecological system safety in a global range. Therefore, environmental remediation of polycyclic aromatic hydrocarbon contaminated sites is of great significance to ecological remediation.

[0003] At present, most of the treatment of hydrocarbon-containing wastewater uses physical, chemical methods or biological remediation technology singly. Among them, the physical and chemical methods such as supercritical extraction, steam extraction, chemical oxidation and electrochemistry have high cost and are easy to cause secondary pollution to the environment. In comparison, the biological remediation technology has less energy consumption and can realize in-situ remediation, and has become a promising green technology for remediation of polycyclic aromatic hydrocarbon contaminated sites, which improves the possibility of environmental safety, but has the problem of long remediation period. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a SiC ceramic membrane biological reactor with integrated ozone catalytic backwashing and a process method for treating hydrocarbon-containing wastewater, which combines chemical remediation and microbial remediation, and the two complement each other, which can solve the problem of high cost of chemical treatment and make up for the deficiency of low efficiency of biological treatment.

[0005] The application adopts the following technical scheme:

[0006] The SiC ceramic membrane biological reactor with integrated ozone catalytic backwashing comprises a reactor main body arranged vertically, and the reactor main body is sequentially divided into an aerobic reaction zone, an anoxic reaction zone and an anaerobic reaction zone from top to bottom;

[0007] The anaerobic reaction zone is connected with a submerged gas collecting device at the top, the submerged gas collecting device is used for collecting methane generated in the anaerobic reaction zone, and the aerobic reaction zone is provided with a plate type ceramic membrane, the upper part of the plate type ceramic membrane is provided with an aeration port and a water outlet, the aeration port is connected with an ozone micro-aeration device, and the water outlet is connected with a water outlet pump;

[0008] The outer wall of the aerobic reaction zone is connected with the bottom of the anaerobic reaction zone by a pipeline to form an outer circulation, the bottom of the anaerobic reaction zone is connected with a substrate barrel, the substrate barrel contains wastewater, carbon source (such as cyclodextrin), nutrient salt and trace element, and contains PAHs of medium ring to low ring, the wastewater in the substrate barrel is treated by the anaerobic reaction zone, the anoxic reaction zone and the aerobic reaction zone, and then flows out from the water outlet of the plate ceramic membrane. Since the substances in the substrate barrel enter from the bottom of the anaerobic reaction zone, the concentration of the whole reactor body is large at the bottom and small at the upper part, and the outer circulation can make the substances circulate and flow, so that the reactor body is more homogeneous and the reaction is more complete.

[0009] The present application has a three-stage special structure with different functional bacteria groups of aerobic, facultative and anaerobic, and realizes vertical circulation of organic matter in fluid mechanics, so that compact facultative / anaerobic granular sludge can be quickly domesticated;

[0010] The ozone in the aerobic reaction zone is prepared by the ozone micro-aeration device, and the ozone is contacted with PAH in the aerobic area, and the ozone is uniformly introduced into the micron-sized plate ceramic membrane (the membrane pore size is 0.45-0.1 microns) in the cavity of the plate ceramic membrane, and then released to the upper layer area of the reactor through the membrane hole. When the ozone passes through the membrane hole, the dirt is oxidized and degraded in the cavity, and the gas is washed at the same time, so that the ceramic membrane is self-cleaning. The ozone micro-bubbles generated by the micro-porous ceramic membrane aeration are beneficial to the gas-liquid mass transfer process, and the remaining ozone dispersed from the cavity catalytic oxidation area oxidizes and degrades the polycyclic aromatic hydrocarbons in the reactor as an electron acceptor, and provides substrates for microorganisms as a carbon source.

[0011] In the anaerobic reaction zone of the present application, the hydrolytic bacteria and the fermenting bacteria can convert macromolecular organic matter into monosaccharides, amino acids, fatty acids, glycerol and the like; the mutual bacteria can decompose the small molecular substances produced by the hydrolytic bacteria and the fermenting bacteria to generate acetic acid and hydrogen; the methanogenic bacteria can produce methane by using hydrogen and carbon dioxide or produce methane by methyl decarboxylation; the nitrate reducing bacteria can reduce nitrate to nitrite by nitrate reductase; the sulfate reducing bacteria can oxidize PAHs by microorganisms and reduce sulfate ions to S 2- ; the PAH degradation bacteria (Pseudomonas, Clostridium and Clostridium etc.) can utilize nitrate or sulfate as an electron acceptor to degrade PAHs into small molecular compounds, and the basic way of this process is to add fumaric acid to produce aromatic succinic acid by glycol radical, and then to further perform methylization reaction, hydroxylation reaction and hydroxylation reaction, and finally to perform beta-oxidation to degrade PAHs;

[0012] In the anoxic reaction zone, the facultative heterotrophic anaerobic microorganisms (denitrifying bacteria) utilize NO3 - and NO2 - as electron acceptors to complete the reaction process with organic matter as electron donor;

[0013] The PAH-degrading bacteria in the aerobic reaction zone convert the PAHs into dihydrodiol compounds under the action of dioxygenase, and then generate diols and other intermediate products under the action of dehydrogenase, and then generate intermediate products through the action of internal / external oxygenase, and finally convert into small molecules participating in the tricarboxylic acid cycle.

[0014] Preferably, the ozone micro-aeration device is connected with an ozone frequency conversion delivery pump, a pressure sensor and a check valve are sequentially arranged on the pipeline of the water outlet connected with the water pump, the check valve can prevent backflow of the water outlet due to pressure difference at the moment when the pump is closed, so as to realize stable and effective data counting of the pressure sensor, the pressure sensor can reflect the membrane pressure to some extent, and is used for real-time monitoring of the membrane pressure and judging the membrane blockage, a multifunctional display control device is connected with the signal of the pressure sensor, and the ozone micro-aeration device is intelligently started when the pressure is too large.

[0015] Preferably, the aerobic reaction zone is connected with a liquid level sensor, the liquid level sensor is connected with a microcontroller, the microcontroller is connected with the water pump through a switch, when the liquid level in the aerobic reaction zone exceeds a certain upper limit value, the microcontroller controls the switch to be opened, and the water pump works, and when the liquid level is lower than a certain lower limit value, the microcontroller controls the switch to be closed, and the water pump stops working.

[0016] Preferably, the reactor body is in a cylindrical shape, and a separator is arranged between the anoxic reaction zone and the anaerobic reaction zone, the separator is an arc-shaped cap, the outer diameter of the separator is the same as the inner diameter of the reactor body, the separator is made of plastic material, and a gas outlet is arranged at the top of the separator and connected with the submerged gas collecting device.

[0017] Preferably, a plurality of sampling ports are further arranged on the anaerobic reaction zone, so as to facilitate experimental research.

[0018] Preferably, the submerged gas collecting device is connected with a collection container through a gas flow meter, the gas flow meter is used for measuring and recording the amount of produced methane, so as to realize effective separation of methane from upper ozone and oxygen.

[0019] Preferably, an overflow port is further arranged on the upper part of the aerobic reaction zone of the reactor body.

[0020] Preferably, the reactor body is arranged in a water bath pool, and an inlet and an outlet are arranged on the water bath pool and the reactor, so as to realize circulation of water flow and guarantee that the temperature of the reactor body is 37℃.

[0021] Preferably, there is no obvious structural division between the aerobic reaction zone and the anoxic reaction zone, and the microorganisms in the aerobic reaction zone and the anoxic reaction zone are enriched on the arc-shaped cap between the anoxic reaction zone and the anaerobic reaction zone, and a small number of aerobic microorganisms are attached to the plate ceramic membrane.

[0022] The aerobic reaction zone is located at the uppermost layer of the reactor, the top half of the main body of the reactor is semi-sealed, the oxygen dissolved in water and the oxygen catalytically converted by ozone ensure the dissolved oxygen concentration, no additional aeration device is needed, the middle layer of the reactor is the anoxic reaction zone, and the lower layer is isolated from oxygen to form the anaerobic reaction zone.

[0023] Preferably, an electromagnetic valve A and a water inlet pump are arranged on the outer circulation pipeline, and the substrate barrel is connected with the water inlet pump through an electromagnetic valve B;

[0024] Preferably, the plate type ceramic membrane is a rectangular silicon carbide plate type ceramic membrane, the top end is adhered with a groove with two ports, the groove is used as an aeration port for feeding ozone and a water outlet port for pumping water, and the rest is composed of a silicon carbide ceramic membrane, the volume of the plate type ceramic membrane accounts for 1 / 4 of the total volume of the aerobic reaction zone, the plate type ceramic membrane is completely immersed in the liquid in the aerobic reaction zone, and the membrane pore size of the plate type ceramic membrane is 0.45-0.1 microns.

[0025] The silicon carbide ceramic membrane has the characteristics of high-efficiency interception, further improves the solid-liquid separation efficiency and intercepts organic matter and microorganisms, realizes the enrichment and concentration of the long generation cycle of PAH degrading bacteria, and is beneficial to maintaining the stable operation of the reactor.

[0026] Further preferably, the rotating speed of the water outlet pump is 60 rpm, the water outlet pump controls the water outlet flux of the plate type ceramic membrane to be 7.8*10 -3 m 3 / m 2 ·min, when the pressure sensor is 60 Kpa, the membrane flux is zero, the ceramic membrane is removed and soaked and cleaned with sodium hypochlorite.

[0027] The device of the application scientifically and reasonably adopts the coupling technology of ozone catalytic oxidation and inorganic ceramic membrane hole catalytic conversion and separation, ozone is released from the ceramic membrane cavity in the form of micro-bubbles, realizing efficient and deep treatment of ozone to ensure the water quality of effluent, and the double goals of ozone gas cavity shearing and flushing to reduce membrane pollution, the gas is ejected from the membrane micro-pore, the shear force makes the pollutants fall off from the membrane hole, at the same time, the liquid around the membrane is turbulent, the hydraulic shear force flushes the membrane surface, effectively controls the formation of filter cake layer and increases the flux. In addition, the micro-bubble ozone in the aerobic / anoxic zone of the upper part of the reaction device enters the system, and the ozone free radicals act as efficient electron acceptors to promote the degradation process of polycyclic aromatic hydrocarbons, and the anaerobic microorganisms in the lower part of the anaerobic zone degrade the polycyclic aromatic hydrocarbons in the same medium after obtaining most or all of the carbon source and energy from the substrate, and efficiently convert PAH into methane. The device is also provided with a submerged gas collecting device, the top of which is connected with a silica gel hose and a gas flow meter, realizing the separation and recovery of methane gas and ozone aeration.

[0028] The process method for treating hydrocarbon-containing wastewater by using the SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing, first, the electromagnetic valve A and the water inlet pump are opened for external circulation for 70 seconds, then the electromagnetic valve B is opened, the wastewater, carbon source, nutrient salt and trace element in the substrate barrel enter the anaerobic reaction zone, anoxic reaction zone and aerobic reaction zone in turn, and different bacterial groups are used to degrade pollutants, the methane produced in the anaerobic reaction zone is collected by the submerged gas collecting device, and the methane production amount is measured by the gas flow meter, at the same time, the ozone micro-aeration device works, ozone enters the plate-type ceramic membrane, catalytic oxidation of colloidal substances in the plate-type ceramic membrane and slows down the membrane pollution, gas flushing and hydraulic shearing slow down the formation of filter cake layer, the remaining ozone released to the aerobic reaction zone continues to catalytic oxidation of refractory pollutants, realizing the biochemical combined efficient degradation of pollutants, that is, the sludge is in full contact with the substrate and the pollutants, and the pollutants are efficiently degraded by microbial degradation and ozone catalytic oxidation;

[0029] The effluent of the reactor, after the wastewater is filtered by the plate-type ceramic membrane, is output from the water outlet of the plate-type ceramic membrane by the water outlet pump.

[0030] Preferably, the process of degrading pollutants is:

[0031] The anaerobic microorganisms in the anaerobic reaction zone can oxidize and degrade PAHs organic matter by using nitrate, sulfate and other electron acceptors, and produce carbon dioxide and methane;

[0032] The facultative heterotrophic anaerobic microorganisms in the anoxic reaction zone complete the reaction process by using NO3 - and NO2 - as electron acceptors and organic matter including pollutants as electron donors in the absence of molecular oxygen;

[0033] In the aerobic reaction zone, the bacteria convert PAHs into dihydrodiols under the action of dioxygenase, and then into diols and other intermediates under the action of dehydrogenase, and then into intermediates under the action of internal / external oxygenase, and finally into small molecules participating in the tricarboxylic acid cycle.

[0034] Preferably, the substances in the substrate barrel enter the anaerobic reaction zone, the anoxic reaction zone and the aerobic reaction zone in turn, and are fully mixed in the reactor body by hydraulic stirring, gas stripping stirring and pneumatic stirring.

[0035] Hydraulic stirring refers to that the substances in the substrate barrel enter from the bottom of the anaerobic reaction zone through the water inlet pump, and then enter the bottom of the anaerobic reaction zone again through the external circulation of the water outlet pump from the aerobic reaction zone to realize hydraulic stirring.

[0036] Gas stripping stirring refers to that the vertical movement of the liquid caused by the rising of the methane gas produced by the microorganisms in the anaerobic reaction zone into the submerged gas collecting device realizes gas stripping stirring.

[0037] Pneumatic stirring refers to that the liquid turbulence caused by the ozone gas jetting out of the membrane holes after entering the plate ceramic membrane realizes hydraulic shear stirring to achieve pneumatic stirring.

[0038] Preferably, when the liquid level sensor senses that the liquid level exceeds the upper limit value, the microcontroller controls the switch to be opened, so that the water pump works and the reactor starts to discharge water, until the liquid level sensor senses that the liquid level is lower than the lower limit value, the water pump is closed and the water discharge is stopped. The water pump is controlled by the liquid level sensor, and when the upper end liquid level is reached, the water pump is opened, and when the lower end liquid level is reached, the water pump is closed, so that the silicon carbide ceramic membrane is immersed in the water phase during the reaction;

[0039] The pressure sensor records the pipeline pressure in real time and displays it on the display control device in real time. When the display control device displays a pressure of 60 Kpa, the ceramic membrane is removed and soaked in sodium hypochlorite for cleaning;

[0040] Preferably, the ozone micro-aeration device is opened periodically, and the control formula for the ozone frequency is as follows:

[0041]

[0042] f(P)=P max

[0043] In the formula:

[0044] P is the transmembrane pressure, kilopascal;

[0045] p max is the maximum transmembrane pressure in a 10-minute period, kilopascal;

[0046] t is the working time of the ozone micro-aeration device in a 10-minute period, seconds;

[0047] Further preferably, the rotation speed of the water inlet pump is 60 rpm, the electromagnetic valve A and the electromagnetic valve B are both intermittent operation, the external circulation controlled by the electromagnetic valve A is 70 seconds / 10 minutes, the water inlet period controlled by the electromagnetic valve B is 40 seconds / 10 minutes, and the reaction device of the application further comprises a time controller for controlling the intermittent opening and closing of the electromagnetic valve A and the electromagnetic valve B.

[0048] The ozone dosage of the aerobic reaction zone is 2-10 mg / L, the dissolved oxygen (mg / L) is about 2.2 mg / L in the aerobic reaction zone, about 0.6 mg / L in the anoxic reaction zone, and <0.2 mg / L in the anaerobic reaction zone.

[0049] The pH value in the substrate barrel is 7.5, the hydraulic retention time is 2-24 hours, the main material of the reactor is organic glass, the total volume is preferably 7L, the volume ratio of the aerobic reaction zone, the anoxic reaction zone and the anaerobic reaction zone is 3:1:1, the total solid (TS) of the aerobic reaction zone is 9.41%, the anoxic reaction zone is 9.49%, and the anaerobic reaction zone is 10.00%.

[0050] According to the characteristics of the difficulty of degrading the hydrocarbon-containing wastewater, the ozone oxidation technology, the microbial repair and the membrane separation technology are combined in the application to solve the degradation problem of the refractory pollutants, delay the ceramic membrane blockage, improve the utilization rate of the ceramic membrane, and provide a theoretical basis and technical support for efficient treatment of hydrocarbon-containing wastewater and collection of biogas resources.

[0051] The details not described in the application can be referred to the prior art.

[0052] The beneficial effects of the application are:

[0053] 1) The application solves the problems of difficult degradation of hydrocarbon-containing wastewater and easy blockage of microporous ceramic membranes in the biological reactor. According to the water quality characteristics of the hydrocarbon-containing wastewater, the device integrates the efficient membrane separation process with the advanced oxidation and microbial repair. The functional bacteria are enriched in the longitudinal vertical functional zones to save the land area. The pollutants in the wastewater are fully contacted with different functional microorganisms through hydraulic shear stirring, gas stripping stirring and pneumatic stirring, so as to be efficiently degraded. At the same time, the ozone micro-bubbles are released to the upper oxidation of the reactor to degrade polycyclic aromatic hydrocarbons. The ozone micro-bubbles are beneficial to the gas-liquid mass transfer process, and the biochemical organic combination achieves the purpose of efficient degradation.

[0054] 2) The anaerobic microorganisms (which should adopt the microorganisms with activity in wastewater, high removal efficiency and gas production) in the application carry out high-density anaerobic digestion to produce methane at the bottom of the reactor, collect the methane by the way of submerged gas collection, effectively separate the methane from ozone and oxygen, and realize the efficient degradation of pollutants and the recovery of clean energy in the reactor at the same time.

[0055] 3) The plate type ceramic membrane is immersed in the aerobic reaction area and located at the front end of the reactor water outlet pump, which reduces sludge loss, effectively separates solid and liquid, and maintains the stable treatment performance of the biological reactor. The hydroxyl radicals generated by ozone in the membrane can effectively degrade colloidal substances that cause membrane pollution, thereby improving the permeation flux. Ozone gas flushing also plays an auxiliary membrane cleaning function, effectively delays membrane clogging, and prolongs the service life of the microporous ceramic membrane. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 The SiC ceramic membrane biological reactor with integrated ozone catalytic backwashing of the application is shown in the structure schematic diagram.

[0057] 1 - aerobic reaction area, 2 - anoxic reaction area, 3 - anaerobic reaction area, 4 - water inlet pump, 5 - electromagnetic valve B, 6 - electromagnetic valve A, 7 - substrate barrel, 8 - aeration port, 9 - water outlet, 10 - submerged gas collecting device, 11 - gas flow meter, 12 - liquid level sensor, 13 - switch, 14 - microcontroller, 15 - plate type ceramic membrane, 16 - ozone micro-aeration device, 17 - ozone frequency conversion delivery pump, 18 - pressure sensor, 19 - display control device, 20 - check valve, 21 - water outlet pump, 22 - separator, 23 - sampling port. DETAILED DESCRIPTION

[0058] To make the technical problems, technical solutions and advantages of the application clearer, specific embodiments will be described in detail below with reference to the drawings, but the application is not limited to this. The application is not described in detail, and is based on the conventional technology in the art.

[0059] Example 1

[0060] A SiC ceramic membrane biological reactor with integrated ozone catalytic backwashing, as shown in the structure schematic diagram, comprises a vertically arranged reactor main body, which is sequentially divided into an aerobic reaction area 1, an anoxic reaction area 2 and an anaerobic reaction area 3 from top to bottom. Figure 1

[0061] The anaerobic reaction area 3 is connected with a submerged gas collecting device 10 at the top, which is used to collect the methane generated in the anaerobic reaction area. The plate type ceramic membrane 15 is arranged in the aerobic reaction area 1, and the upper part of the plate type ceramic membrane 15 is provided with an aeration port 8 and a water outlet 9. The aeration port 8 is connected with an ozone micro-aeration device 16, and the water outlet 9 is connected with a water outlet pump 21.

[0062] ​The outer wall of the aerobic reaction zone 1 is connected with the bottom of the anaerobic reaction zone 3 through a pipeline to form an outer circulation, the bottom of the anaerobic reaction zone 3 is connected with the substrate barrel 7, the substrate barrel 7 contains wastewater, carbon source (such as cyclodextrin), nutrient salt and trace element, and contains PAHs of medium ring to low ring, the wastewater in the substrate barrel 7 is discharged from the water outlet of the plate ceramic membrane 15 after being treated by the anaerobic reaction zone 3, the anoxic reaction zone 2 and the aerobic reaction zone 1. Since the substances in the substrate barrel 7 enter from the bottom of the anaerobic reaction zone, the concentration of the whole reactor body is large at the bottom and small at the upper part, and the outer circulation can make the substances circulate and flow, so that the reactor body is more homogeneous and the reaction is more complete.

[0063] The present application has the three-stage special structure of rich aerobic, facultative and anaerobic different functional flora, realizes the vertical circulation flow of organic matter in the fluid mechanics, and can quickly domesticate the compact facultative / anaerobic granular sludge;

[0064] The ozone in the aerobic reaction zone 1 is prepared by the ozone micro-aeration device, and the ozone is uniformly introduced into the micron-sized plate ceramic membrane (the membrane pore size is 0.45-0.1 microns) in the cavity of the plate ceramic membrane 15, is released to the upper layer area of the reactor through the membrane hole, is oxidized and degraded in the cavity when passing through the membrane hole, is washed by the synchronous gas, and the self-cleaning of the ceramic membrane is realized. The ozone micro-bubbles generated by the micro-porous ceramic membrane aeration are beneficial to the gas-liquid mass transfer process, the remaining ozone diffused from the cavity catalytic oxidation area oxidizes and degrades the polycyclic aromatic hydrocarbon in the reactor as an electron acceptor, and provides a substrate for microorganisms as a carbon source.

[0065] In the anaerobic reaction zone 3 of the present application, the hydrolytic bacteria and the fermenting bacteria can convert macromolecular organic matter into monosaccharides, amino acids, fatty acids, glycerol and the like; the mutual bacteria can decompose the small molecular substances generated by the hydrolytic bacteria and the fermenting bacteria to generate acetic acid and hydrogen; the methanogenic bacteria can produce methane by using hydrogen and carbon dioxide or produce methane by methyl decarboxylation; the nitrate reducing bacteria can reduce nitrate to nitrite by nitrate reductase; the sulfate reducing bacteria can oxidize PAHs by microorganisms and reduce sulfate ions to S 2- ; the PAH degradation bacteria (Pseudomonas, Clostridium and Clostridium etc.) can degrade PAHs to small molecular compounds by using nitrate or sulfate as an electron acceptor, and the basic way of the process is to add fumaric acid to produce aromatic succinic acid by glycol radical, and then to perform methylization reaction, hydroxylation reaction and hydroxylation reaction, and finally to degrade PAHs by beta-oxidation;

[0066] In the anoxic reaction zone 2, the facultative heterotrophic anaerobic microorganism (denitrifying bacteria) uses NO3 - and NO2 - as an electron acceptor to complete the reaction process under the condition of no molecular oxygen, and uses organic matter in pollutants as an electron donor;

[0067] The PAH-degrading bacteria in the aerobic reaction zone 1 convert the PAHs into dihydrodiol compounds under the action of dioxygenase, and then generate diols and other intermediate products under the action of dehydrogenase, and then generate intermediate products through the action of internal / external dioxygenase, and finally convert into small molecules participating in the tricarboxylic acid cycle.

[0068] Example 2

[0069] The SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing has the structure shown in Example 1, except that the ozone micro-aeration device 16 is connected to an ozone frequency conversion delivery pump 17, and a pressure sensor 18 and a check valve 20 are sequentially arranged on the pipeline of the water outlet 9 connected to the water outlet pump 21. The check valve 20 can prevent backflow of water due to pressure difference at the moment when the pump is closed, so as to realize stable and effective data counting of the pressure sensor. The pressure sensor 18 can reflect the transmembrane pressure to some extent, and is used for real-time monitoring of the transmembrane pressure and judging the membrane clogging condition. The pressure sensor 18 is signal-connected to a multifunctional display control device 19, which is signal-connected to the ozone micro-aeration device 16. When the pressure is too large, the ozone micro-aeration device is intelligently started.

[0070] Example 3

[0071] The SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing has the structure shown in Example 2, except that the aerobic reaction zone 1 is connected to a liquid level sensor 12, the liquid level sensor 12 is connected to a microcontroller 14, and the microcontroller 14 is connected to the water outlet pump 21 through a switch 13. When the liquid level in the aerobic reaction zone exceeds a certain upper limit value, the microcontroller 14 controls the switch to be turned on, and the water outlet pump 21 works. When the liquid level is lower than a certain lower limit value, the microcontroller 14 controls the switch to be turned off, and the water outlet pump 21 stops working.

[0072] Example 4

[0073] The SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing has the structure shown in Example 3, except that the reactor main body is in a cylindrical shape, and a separator 22 is arranged between the anoxic reaction zone and the anaerobic reaction zone. The separator 22 is an arc-shaped cap, the outer diameter of which is the same as the inner diameter of the reactor main body. The separator 22 is made of plastic material, and the top of the separator 22 is provided with a gas outlet hole, which is connected to the submerged gas collecting device.

[0074] Preferably, a plurality of sampling ports 23 are further arranged on the anaerobic reaction zone, which facilitates experimental research.

[0075] Example 5

[0076] A SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing, the structure of which is shown in Example 4, except that the submerged gas collection device is connected to the collection container through a gas flow meter 11, which is used to measure and record the amount of methane produced, and to effectively separate methane from the upper layer of ozone and oxygen;

[0077] Preferably, an overflow port is further provided at the upper part of the aerobic reaction zone of the reactor body.

[0078] Preferably, the reactor body is placed in a water bath, and the water bath and the reactor are provided with an inlet and an outlet for circulating water flow to ensure that the temperature of the reactor body is 37℃.

[0079] Preferably, there is no obvious structural division between the aerobic reaction zone and the anoxic reaction zone, and the microorganisms in the aerobic reaction zone and the anoxic reaction zone are enriched on the arc-shaped cap between the anoxic reaction zone and the anaerobic reaction zone, and a small number of aerobic microorganisms are attached to the plate ceramic membrane.

[0080] The aerobic reaction zone is located at the uppermost layer of the reactor, and the top of the reactor body is semi-sealed, and the dissolved oxygen concentration is ensured by the oxygen dissolved in water and the oxygen catalytically converted by ozone, without the need for additional aeration devices. The middle layer of the reactor is the anoxic reaction zone, and the lower layer is isolated from oxygen to form the anaerobic reaction zone. By reasonably designing the longitudinal space, the functional bacterial flora with different oxygen requirements are enriched, and the metabolic diversity of the functional bacterial flora is realized.

[0081] Example 6

[0082] A SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing, the structure of which is shown in Example 5, except that an electromagnetic valve A 6 and a water inlet pump 4 are provided on the outer circulation pipeline, and the substrate barrel 7 is connected to the water inlet pump 4 through an electromagnetic valve B 5;

[0083] Preferably, the plate ceramic membrane 15 is a rectangular silicon carbide plate ceramic membrane, the top end of which is adhered to a groove with two openings, which are respectively an aeration port for ozone and a water outlet port for pumping water, and the rest is composed of silicon carbide ceramic membrane. The volume of the plate ceramic membrane accounts for 1 / 4 of the total volume of the aerobic reaction zone, the plate ceramic membrane is completely immersed in the liquid in the aerobic reaction zone, and the membrane pore size of the plate ceramic membrane is 0.45-0.1 microns.

[0084] The silicon carbide ceramic membrane has the characteristics of high efficient interception, further improves the solid-liquid separation efficiency, and intercepts organic matter and microorganisms, realizes the enrichment and concentration of the long generation cycle of PAH degradation bacteria, and is beneficial to maintaining the stable operation of the reactor. Therefore, the application can realize the resource recycling of biogas and the efficient degradation of polycyclic aromatic hydrocarbons at the same time, realizes the function division in the integrated reactor to enrich different functional bacteria, and the degradation rate can reach more than 80%, which provides a feasible reference for the multifunctional integrated large-scale membrane bioreactor, and provides a solution for the treatment of refractory PAH pollutants and the application bottleneck of membrane pollution.

[0085] Further preferably, the rotation speed of the water outlet pump 21 is 60 rpm, the water outlet flux of the water outlet pump control plate type ceramic membrane is 7.8*10 -3 m 3 / m 2 ·min, when the pressure sensor is 60Kpa, the membrane flux is zero, and the ceramic membrane is removed and soaked and cleaned with sodium hypochlorite.

[0086] The device of the application scientifically and reasonably adopts the coupling technology of ozone catalytic oxidation and in-hole catalytic conversion and separation of inorganic ceramic membrane, ozone is released from the cavity of the ceramic membrane in the form of micro-bubbles, realizes efficient and deep treatment of ozone to ensure the water quality of the effluent, and realizes the double goals of shear and flushing in the ozone gas cavity to reduce membrane pollution, the gas is ejected from the membrane micropore, the shear force makes the pollutants fall off from the membrane hole, at the same time, the liquid around the membrane is turbulent, the hydraulic shear force flushes the membrane surface, effectively controls the formation of filter cake layer and increases the flux. In addition, the micro-bubble ozone in the aerobic / anoxic zone of the upper part of the reaction device enters the system, and the ozone free radicals act as efficient electron acceptors to promote the degradation process of polycyclic aromatic hydrocarbons, and the microorganisms in the anaerobic zone of the lower part obtain most or all of the carbon source and energy from the substrate, and then degrade the polycyclic aromatic hydrocarbons in the same medium, and convert the PAH into methane. The device is also provided with a submerged gas collecting device, the top of which is connected with a silica gel hose and a gas flow meter, which realizes the separation and recovery of methane gas and ozone aeration.

[0087] Example 7

[0088] The process method for treating hydrocarbon-containing wastewater by using the SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing, first, the electromagnetic valve A 6 and the water inlet pump 4 are opened for external circulation for 70 seconds, then the electromagnetic valve B 5 is opened, and the wastewater, carbon source, nutrient salt and trace element in the substrate barrel 7 enter the anaerobic reaction zone 3, the anoxic reaction zone 2 and the aerobic reaction zone 1 in turn, and pollutants are degraded by using different bacterial flora, the methane generated in the anaerobic reaction zone is collected by the submerged gas collection device 10, and the amount of generated methane is measured by the gas flow meter 11. The opening and closing of the ozone micro-aeration device is controlled by the display control device 19, when the ozone micro-aeration device is opened, the ozone enters the plate ceramic membrane 15, the colloidal substances are catalytically oxidized in the plate ceramic membrane, and the membrane pollution is slowed down, the gas flushing and the hydraulic shearing slow down the formation of the filter cake layer, the remaining ozone released into the aerobic reaction zone continues to catalytically oxidize the refractory pollutants, and the biochemical combined efficient degradation of the pollutants is realized, that is, the sludge is fully contacted with the substrate and the pollutants, and the pollutants are efficiently degraded by the microbial degradation and the ozone catalytic oxidation;

[0089] The reactor effluent, after the wastewater is filtered and treated by the plate ceramic membrane, is output from the water outlet of the plate ceramic membrane by the water outlet pump 21.

[0090] Preferably, the process for degrading pollutants is as follows:

[0091] The anaerobic microorganisms in the anaerobic reaction zone can oxidize and degrade PAHs organic matter by using nitrate, sulfate and other electron acceptors, and generate carbon dioxide and methane;

[0092] The facultative heterotrophic anaerobic microorganisms in the anoxic reaction zone utilize NO3 - and NO2 - as electron acceptors to complete the reaction process by using organic matter including pollutants as electron donor;

[0093] In the aerobic reaction zone, the bacteria convert PAHs into dihydrodiol compounds under the action of dioxygenase, then generate diol and other intermediate products under the action of dehydrogenase, and then degrade the intermediate products by using endo / exo oxygenase to finally convert into small molecules participating in the tricarboxylic acid cycle.

[0094] Example 8

[0095] The process method for treating hydrocarbon-containing wastewater by using the SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing is as described in Example 7, except that after the substances in the substrate barrel 7 enter the anaerobic reaction zone 3, the anoxic reaction zone 2 and the aerobic reaction zone 1 in turn, the substances are fully mixed in the reactor body by hydraulic stirring, gas stripping stirring and pneumatic stirring;

[0096] The hydraulic stirring refers to that the substances in the substrate barrel enter from the bottom of the anaerobic reaction zone through the water inlet pump, and then enter the bottom of the anaerobic reaction zone again through external circulation from the water outlet of the aerobic reaction zone, so as to realize the hydraulic stirring.

[0097] Gas stripping refers to the process that the methane gas produced by microorganisms in the anaerobic reaction zone rises into the submerged gas collecting device, causing the vertical movement of liquid to achieve gas stripping;

[0098] Pneumatic agitation refers to the ozone gas entering the plate ceramic membrane and being sprayed out of the membrane holes to cause the turbulent movement of liquid around the membrane to achieve hydraulic shear agitation.

[0099] Example 9

[0100] A process method for treating hydrocarbon-containing wastewater by using a SiC ceramic membrane bioreactor with integrated ozone catalytic backwashing, as described in Example 7, except that when the liquid level sensor 12 senses that the liquid level exceeds the upper limit value, the microcontroller 14 controls the switch to open, so that the effluent pump works and the reactor starts to discharge water, until the liquid level sensor senses that the liquid level is lower than the lower limit value, the effluent pump is closed and the water discharge is stopped. The effluent pump 21 is controlled by the liquid level sensor 12, and the effluent pump is opened when the upper end liquid level is reached, and the effluent pump is closed when the lower end liquid level is reached. During the reaction, the silicon carbide ceramic membrane is ensured to be immersed in the aqueous phase;

[0101] The pressure sensor records the pipeline pressure in real time and displays it on the display control device in real time. When the pressure displayed on the display control device is 60 Kpa, the ceramic membrane is removed and soaked in sodium hypochlorite for cleaning;

[0102] Preferably, the ozone micro-aeration device is opened periodically, and the control of the ozone input frequency is calculated according to the following formula:

[0103]

[0104] f(P)=P max

[0105] In the formula:

[0106] P is the transmembrane pressure, kilopascal;

[0107] p max is the maximum transmembrane pressure in a 10-minute period, kilopascal;

[0108] t is the working time of the ozone micro-aeration device in a 10-minute period, seconds;

[0109] Further preferably, the speed of the water inlet pump is 60 rpm, the electromagnetic valve A and the electromagnetic valve B are both intermittent, the external circulation controlled by the electromagnetic valve A is 70 seconds / 10 minutes, and the water inlet period controlled by the electromagnetic valve B is 40 seconds / 10 minutes. The reaction device of the present application further comprises a time controller for controlling the intermittent opening and closing of the electromagnetic valve A and the electromagnetic valve B.

[0110] The ozone dosage of the aerobic reaction zone is 2-10 mg / L, the dissolved oxygen is about 2.2 mg / L in the aerobic reaction zone, about 0.6 mg / L in the anoxic reaction zone, and <0.2 mg / L in the anaerobic reaction zone;

[0111] The pH value in the matrix barrel is 7.5, the hydraulic retention time is 2-24 hours, the main body material of the reactor is organic glass, the total volume is preferably 7L, the volume ratio of the aerobic reaction zone, the anoxic reaction zone and the anaerobic reaction zone is 3:1:1, the total solid (TS) of the aerobic reaction zone is 9.41%, the anoxic reaction zone is 9.49%, and the anaerobic reaction zone is 10.00%.

[0112] The above is the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can also make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A process for treating hydrocarbon-containing wastewater using an integrated ozone catalytic backwashing SiC ceramic membrane bioreactor, characterized in that, an integrated ozone catalytic backwashing SiC ceramic membrane bioreactor is used, wherein the integrated ozone catalytic backwashing SiC ceramic membrane bioreactor is a reactor in which a SiC ceramic membrane is integrated with a bioreactor, and the reactor is configured to perform ozone catalytic backwashing of the SiC ceramic membrane. The SiC ceramic membrane bioreactor comprises a reactor body arranged vertically, which is sequentially divided into an aerobic reaction zone, an anoxic reaction zone and an anaerobic reaction zone from top to bottom; The anaerobic reaction zone is connected with a submerged gas collecting device at the top, which is used for collecting the methane generated in the anaerobic reaction zone, and the aerobic reaction zone is provided with a plate ceramic membrane, the upper part of the plate ceramic membrane is provided with an aeration port and a water outlet, the aeration port is connected with an ozone micro-aeration device, and the water outlet is connected with a water outlet pump; The outer wall of the aerobic reaction zone is connected with the bottom of the anaerobic reaction zone through a pipeline to form an external circulation, the bottom of the anaerobic reaction zone is connected with a substrate barrel, the substrate barrel is filled with wastewater, carbon source, nutrient salt and trace elements, and the wastewater in the substrate barrel is treated by the anaerobic reaction zone, the anoxic reaction zone and the aerobic reaction zone, and then flows out from the water outlet of the plate ceramic membrane; The ozone micro-aeration device is connected with an ozone frequency conversion delivery pump, a pressure sensor and a check valve are sequentially arranged on the pipeline connected with the water outlet, and the pressure sensor is connected with a display control device, which is connected with the ozone micro-aeration device, and the ozone micro-aeration device is intelligently started when the pressure is too high; An electromagnetic valve A and a water inlet pump are arranged on the external circulation pipeline, and the substrate barrel is connected with the water inlet pump through an electromagnetic valve B; The plate ceramic membrane is a rectangular silicon carbide plate ceramic membrane, the volume of the plate ceramic membrane accounts for 1 / 4 of the total volume of the aerobic reaction zone, the plate ceramic membrane is completely immersed in the liquid in the aerobic reaction zone, and the membrane pore size of the plate ceramic membrane is 0.1-0.45 microns; The rotation speed of the water outlet pump is 60 rpm, the membrane flux is zero when the pressure sensor is 60 Kpa, and the ceramic membrane is removed and soaked and cleaned with sodium hypochlorite; The submerged gas collecting device is connected with a gas flow meter and a collecting container, and the gas flow meter is used for measuring the amount of produced methane; The method comprises: Firstly, the electromagnetic valve A and the water inlet pump are started to realize external circulation for 70 seconds, then the electromagnetic valve B is started, and the wastewater, carbon source, nutrient salt and trace elements in the substrate barrel enter the anaerobic reaction zone, the anoxic reaction zone and the aerobic reaction zone in sequence, different bacterial groups are used to degrade pollutants, the methane produced in the anaerobic reaction zone is collected by the submerged gas collecting device, and the amount of produced methane is measured by the gas flow meter, at the same time, the ozone micro-aeration device works, ozone enters the plate ceramic membrane, catalyzing and oxidizing colloidal substances in the plate ceramic membrane and slowing down membrane pollution, the remaining ozone released into the aerobic reaction zone continues to catalyze and oxidize refractory pollutants, and biochemical combined efficient degradation of pollutants is realized; After the wastewater is treated by the plate ceramic membrane, the wastewater flows out from the water outlet of the plate ceramic membrane by the water outlet pump; After the substances in the substrate barrel enter the anaerobic reaction zone, the anoxic reaction zone and the aerobic reaction zone in sequence, the substances are fully mixed in the reactor body by hydraulic stirring, gas stripping stirring and pneumatic stirring; The hydraulic stirring refers to that the substances in the substrate barrel enter the anaerobic reaction zone from the bottom of the anaerobic reaction zone through the water inlet pump, and then enter the anaerobic reaction zone again from the aerobic reaction zone through external circulation to realize hydraulic stirring; The gas stripping stirring refers to that the liquid is vertically moved to realize gas stripping stirring in the process that the methane gas produced by microorganisms in the anaerobic reaction zone rises into the submerged gas collecting device; The pneumatic agitation refers to that liquid around the membrane is tumbled and subjected to hydraulic shearing agitation by the ozone gas jetted out from the membrane holes after the ozone gas enters the plate type ceramic membrane.

2. The process for treatment of hydrocarbon containing wastewater by integrated ozone catalytic backwash SiC ceramic membrane bioreactor as claimed in claim 1 wherein, The aerobic reaction zone is connected with a liquid level sensor, the liquid level sensor is connected with a microcontroller, the microcontroller is connected with a switch, and the water pump is connected with the switch; when the liquid level in the aerobic reaction zone exceeds a certain upper limit value, the microcontroller controls the switch to be opened, and the water pump works; when the liquid level is lower than a certain lower limit value, the microcontroller controls the switch to be closed, and the water pump stops working.

3. The process for treatment of hydrocarbon containing wastewater by integrated ozone catalytic backwash SiC ceramic membrane bioreactor as claimed in claim 1 wherein, The reactor body is in a cylindrical shape, and a separator is arranged between the anoxic reaction zone and the anaerobic reaction zone, the separator is an arc-shaped cap, the outer diameter of the separator is the same as the inner diameter of the reactor body, the separator is made of plastic material, and a gas outlet is arranged at the top of the separator and connected with the submerged gas collecting device. A plurality of sampling ports are arranged on the anaerobic reaction zone, which facilitates experimental research.

4. The process for treatment of hydrocarbon containing wastewater by integrated ozone catalytic backwash SiC ceramic membrane bioreactor as claimed in claim 3 wherein, An overflow port is further arranged on the upper part of the aerobic reaction zone of the reactor body.

5. The process for treatment of hydrocarbon containing wastewater by integrated ozone catalytic backwash SiC ceramic membrane bioreactor as claimed in claim 2 wherein, When the liquid level sensor senses that the liquid level exceeds the upper limit value, the microcontroller controls the switch to be opened, so that the water pump works and the reactor starts to discharge water, until the liquid level sensor senses that the liquid level is lower than the lower limit value, the water pump is closed and the water discharge is stopped. The pressure sensor records the pipeline pressure in real time and displays the pressure on the display control device in real time, when the display control device displays that the pressure is 60 Kpa, the ceramic membrane is removed and soaked and cleaned with sodium hypochlorite; The rotation speed of the water inlet pump is 60 rpm, the electromagnetic valve A and the electromagnetic valve B are both intermittent working, the external circulation controlled by the electromagnetic valve A is 70 seconds / 10 minutes, and the water inlet period controlled by the electromagnetic valve B is 40 seconds / 10 minutes; The ozone dosage of the aerobic reaction zone is 2-10 mg / L, the dissolved oxygen is about 2.2 mg / L in the aerobic reaction zone, about 0.6 mg / L in the anoxic reaction zone, and less than 0.2 mg / L in the anaerobic reaction zone; The pH value in the substrate barrel is 7.5, the hydraulic retention time is 2-24 hours, the material of the reactor body is organic glass, and the volume ratio of the aerobic reaction zone, the anoxic reaction zone and the anaerobic reaction zone is 3:1:

1. The pH value in the substrate barrel is 7.5, the hydraulic retention time is 2-24 hours, the material of the reactor body is organic glass, and the volume ratio of the aerobic reaction zone, the anoxic reaction zone and the anaerobic reaction zone is 3:1:1.

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