A treatment method and device for propylene oxide co-production methyl tertiary butyl ether wastewater

Abstract

The present application belongs to the technical field of microbial electrochemistry, and particularly relates to a propylene oxide coproduction methyl tert-butyl ether wastewater treatment method and device. The propylene oxide coproduction methyl tert-butyl ether wastewater treatment method provided by the present application comprises the following steps: anaerobic biological treatment of propylene oxide coproduction methyl tert-butyl ether wastewater and a microbial synergist, and voltage is applied during the anaerobic biological treatment; the microbial synergist comprises lactic acid, dipotassium hydrogen phosphate, ammonium chloride, magnesium chloride, calcium chloride, zinc sulfate, sodium bicarbonate, ferrous sulfate, fulvic acid, manganese chloride, EDTA-2Na and trace elements, and the trace elements comprise boric acid, copper sulfate, sodium molybdate, nickel chloride and cobalt chloride. By regulating the components of the microbial synergist and utilizing the synergistic effect of the electrochemical technology, the microbial synergist and the anaerobic reaction, the growth environment of the microorganism is optimized, the pollutant degradation rate and the methane content in the anaerobic digestion process are improved, and the wastewater treatment efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of microbial electrochemical technology, specifically to a method and apparatus for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide. Background Technology

[0002] Wastewater generated during the co-production of methyl tert-butyl ether from propylene oxide is petrochemical wastewater, characterized by its strong recalcitrant nature and high concentrations of organic pollutants and toxic chemicals, posing a serious threat to the ecological environment. Traditional physicochemical treatment methods, such as adsorption, precipitation, and chemical oxidation, while capable of removing some pollutants, generally suffer from high costs, complex operations, and the potential for secondary pollution, failing to meet the demands of modern industrial sustainable development. Furthermore, the extensive use of chemical reagents in chemical oxidation not only increases costs but may also introduce new environmental pollution. Therefore, a green, efficient, and sustainable wastewater treatment method is urgently needed.

[0003] Against this backdrop, anaerobic biological treatment technology has gradually become a powerful means of treating wastewater from the co-production of methyl tert-butyl ether (MTBE) from propylene oxide, due to its excellent removal efficiency of organic pollutants and low operating costs. However, this wastewater contains various substances that are toxic and inhibitory to anaerobic microorganisms, such as petroleum hydrocarbons, phenols, ketones, and ethers. These components significantly reduce the metabolic activity of anaerobic microorganisms, resulting in low efficiency of traditional anaerobic treatment. Therefore, relying solely on conventional anaerobic biological treatment methods is insufficient to achieve efficient purification of this type of wastewater.

[0004] In recent years, electric field-assisted anaerobic treatment technology has attracted widespread attention as an innovative treatment method due to its ability to effectively enhance microbial activity. An applied electric field can enhance the permeability of microbial cell membranes, promoting the transport of substrates and nutrients, thereby improving the metabolic capacity of anaerobic microorganisms. Simultaneously, appropriate electric field conditions can accelerate the oxidation-reduction reactions of organic matter in wastewater, improving wastewater purification efficiency. This technology shows broad application prospects in treating highly toxic and recalcitrant organic wastewater.

[0005] Chinese patent application CN113023875A, published on June 25, 2021, discloses a bioelectrochemical device with a built-in rotating electrode for treating recalcitrant wastewater. The device includes an anaerobic reactor, an anode and a cathode respectively disposed within the anaerobic reactor, and a reference electrode disposed between the anode and cathode. The anode and cathode are rotatably disposed relative to the anaerobic reactor, and their rotation directions are the same. This device can effectively improve the shortcomings of anaerobic systems, such as the accumulation of volatile fatty acids and long start-up time, while promoting the synergistic effect between electrochemically active bacteria and traditional anaerobic bacteria, achieving efficient removal of recalcitrant organic matter. The COD content in the recalcitrant wastewater is 2500±200 mg / L, and the BOD5 content is 300±50 mg / L.

[0006] However, the aforementioned device is only designed for the treatment of high COD wastewater and does not disclose its application in the treatment of propylene oxide co-production methyl tert-butyl ether wastewater containing high concentrations of organic pollutants and toxic chemicals. The anaerobic treatment efficiency of this type of wastewater remains low. Summary of the Invention

[0007] The purpose of this invention is to provide a method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide, thereby solving the problem of low efficiency in existing anaerobic treatment methods.

[0008] The second objective of this invention is to provide a treatment device for wastewater from the co-production of methyl tert-butyl ether from propylene oxide, thereby solving the problem of low treatment efficiency in existing treatment devices.

[0009] To solve the above-mentioned technical problems, the technical solution of the treatment method for wastewater from the co-production of methyl tert-butyl ether from propylene oxide of the present invention is as follows:

[0010] A method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide includes the following steps: anaerobic biological treatment of the wastewater and a microbial synergist, wherein a voltage is applied during the anaerobic biological treatment process; the microbial synergist includes lactic acid, dipotassium hydrogen phosphate, ammonium chloride, magnesium chloride, calcium chloride, zinc sulfate, sodium bicarbonate, ferrous sulfate, fulvic acid, manganese chloride, EDTA-2Na, and trace elements, wherein the trace elements include boric acid, copper sulfate, sodium molybdate, nickel chloride, and cobalt chloride.

[0011] This invention improves upon existing technologies by providing a method for treating wastewater from the co-production of methyl tert-butyl ether (MTBE) from propylene oxide. By regulating the composition of the microbial synergist, the activity of microorganisms in the system is enhanced, thereby improving the stability and efficiency of wastewater treatment. Furthermore, by utilizing the synergistic effect of electrochemical technology, microbial synergists, and anaerobic reactions, the growth environment of microorganisms is optimized, significantly increasing the degradation rate of pollutants during anaerobic digestion and raising the methane content of biogas. Compared to traditional anaerobic digestion methods, the electrochemically enhanced anaerobic reactor can efficiently and stably treat high-concentration MTBE wastewater, improving overall wastewater treatment efficiency.

[0012] The treatment method provided by this invention does not rely on chemical agents and can effectively reduce the environmental burden during the treatment process; the organic pollutants in the wastewater are degraded by microbial metabolism, and the generated methane can be used for energy recovery, further reducing the demand for external energy and meeting the requirements of green and environmentally friendly sustainable development.

[0013] To further improve the efficiency of anaerobic treatment, preferably, the microbial synergist comprises the following components: lactic acid 2-2.5 g / L, dipotassium hydrogen phosphate 0.2-0.255 g / L, ammonium chloride 0.15-0.2 g / L, magnesium chloride hexahydrate 0.08-0.1 g / L, calcium chloride dihydrate 0.02-0.05 g / L, zinc sulfate heptahydrate 0.001-0.005 g / L, sodium bicarbonate 0.02-0.05 g / L, ferrous sulfate heptahydrate 0.005-0.010 g / L, fulvic acid 0.02-0.05 g / L, manganese chloride tetrahydrate 0.002-0.005 g / L, trace element solution 1-5 mL / L, and EDTA-2Na. The trace element solution comprises the following components: boric acid 0.1–0.15 g / L, copper sulfate pentahydrate 0.03–0.05 g / L, sodium molybdate 0.005–0.010 g / L, nickel chloride hexahydrate 0.004–0.005 g / L, cobalt chloride hexahydrate 0.003–0.005 g / L, and water; the pH of the microbial synergist is 6.5–7.5.

[0014] To further improve the efficiency of anaerobic treatment, preferably, the volume ratio of propylene oxide co-production methyl tert-butyl ether wastewater to microbial synergist in the anaerobic biological treatment process is (10-12):1.

[0015] By adjusting key parameters such as pH, oxidation-reduction potential (ORP), and dissolved oxygen concentration, the long-term stable operation of anaerobic reactions in complex wastewater environments is ensured, while maintaining efficient pollutant degradation and methane generation.

[0016] Preferably, the voltage is applied in four stages during the anaerobic biological treatment process: the voltage applied in the first stage is 0.7-0.8V, the voltage applied in the second stage is 0.9-1.0V, the voltage applied in the third stage is 1.1-1.2V, and the voltage applied in the fourth stage is 1.3-1.4V.

[0017] Preferably, the pH in the anaerobic biological treatment process is 6.5-7.5, the temperature is 35-37℃, and the dissolved oxygen concentration is less than 0.1 mg / L.

[0018] To further improve the stability of the anaerobic reaction, preferably, microbial acclimation is performed before anaerobic biological treatment. The microbial acclimation includes the following steps: under the condition of applied voltage, anaerobic biological treatment is performed on propylene oxide co-production methyl tert-butyl ether wastewater and microbial enhancer in a volume ratio of (4-5):1 until the current drops to below 10% of the highest current of the reaction system, and then the propylene oxide co-production methyl tert-butyl ether wastewater and microbial enhancer are replaced and anaerobic biological treatment is performed until the current stabilizes.

[0019] The technical solution of the wastewater treatment device for the co-production of methyl tert-butyl ether from propylene oxide of the present invention is as follows:

[0020] A treatment device for wastewater from the co-production of methyl tert-butyl ether from propylene oxide includes an anaerobic biological treatment reactor. The bottom wall of the anaerobic biological treatment reactor is provided with an anode plate and a cathode plate extending towards the top of the anaerobic biological treatment reactor, and the anode plate and cathode plate are spaced apart.

[0021] The device for treating propylene oxide co-production methyl tert-butyl ether wastewater provided by this invention utilizes anode and cathode plates spaced apart on the bottom wall of the anaerobic biological treatment reactor. This arrangement of the anode and cathode plates provides a larger specific surface area, resulting in a more uniform voltage distribution and preventing excessively high or low voltage in certain areas. The synergistic effect of electrochemical technology, microbial synergists, and anaerobic reaction significantly improves the pollutant degradation rate during the two-phase anaerobic digestion process and increases the methane content of the biogas.

[0022] To further enhance the synergistic effect of electrochemical and anaerobic reactions, preferably, when the length, width, and height of the inner cavity of the anaerobic biological treatment reactor are L, W, and H respectively, the lengths of the anode plate and the cathode plate are... Width is Height is The distance between the anode plate and the cathode plate is

[0023] Preferably, the anaerobic biological treatment reactor has a three-phase separation device located above the anode and cathode plates. The anaerobic biological treatment reactor employs an optimized three-phase separation device and anode and cathode plates to achieve efficient separation of gas, liquid, and solid phases, maintain reactor stability, reduce operation and maintenance complexity, and adapt to different wastewater treatment needs through high-precision voltage regulation, demonstrating excellent applicability and economic benefits.

[0024] To further improve resource utilization, preferably, the anaerobic biological treatment reactor has a circulating liquid outlet on the side wall below the three-phase separation device and a circulating liquid inlet on the side wall near the bottom. The circulating liquid outlet and inlet are connected by a reflux pipe, which is equipped with a circulation pump. After anaerobic biological treatment, the concentration of pollutants in the reaction zone below the anaerobic biological treatment reactor is lower than that in the solution above. This circulation device can dilute toxic substances and pollutants in the solution above the reactor, reduce their inhibitory effect on microorganisms, enhance the reactor's load resistance, and strengthen mud-water mixing.

[0025] To further accelerate the efficiency of anaerobic biological reaction, preferably, the anaerobic biological treatment reactor is equipped with a stirring device for stirring the materials inside the reactor. The stirring device is used to thoroughly mix the substrate and anaerobic sludge, ensuring uniform distribution of materials within the reactor and maintaining temperature uniformity.

[0026] To further facilitate the collection of gases and liquids produced by the anaerobic biological reaction, preferably, a gas collector is provided at the top of the anaerobic biological treatment reactor to collect the gases separated by the three-phase separation device, and a liquid outlet is provided on the side wall near the top of the three-phase separation device.

[0027] In order to achieve real-time monitoring of pH and redox potential within the reaction system, and to further regulate the anaerobic biological reaction, preferably, a pH / ORP composite probe is provided between the anode and cathode plates that are spaced apart, for monitoring the pH and redox potential of the system during the anaerobic biological reaction process. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the wastewater treatment device for the co-production of methyl tert-butyl ether from propylene oxide in Embodiment 1 of the present invention.

[0029] Figure 2 for Figure 1 Top view;

[0030] Figure 3 This is a graph showing the periodic fluctuations of the current after microbial domestication in the treatment method of Embodiment 2 of the present invention;

[0031] Figure 4The graph shows the changes in COD concentration and voltage at different treatment stages.

[0032] Figure 5 The graph shows the changes in COD removal rate and volumetric loading rate at different treatment stages.

[0033] Figure 6 This is a graph showing the pH changes of the effluent at different treatment stages;

[0034] Figure 7 The graph shows the changes in VFAs concentration in the effluent at different treatment stages.

[0035] In the attached diagram: 1. Anaerobic biological treatment reactor 1; 2. Anode plate; 3. Cathode plate; 4. Three-phase separation device; 5. Motor; 6. Discharge port; 7. Stirring shaft; 8. Stirring paddle; 9. pH / ORP composite probe; 10. Controller; 11. Sludge zone; 12. Anode plate holder; 13. Bottom wall; 14. Constant voltage DC power supply; 15. Gas collector; 16. Liquid inlet; 17. Liquid outlet; 18. Circulating liquid outlet; 19. Circulating liquid inlet; 20. Circulating pump; 21. Cathode plate holder. Detailed Implementation

[0036] The technical concept of the method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide according to the present invention is as follows:

[0037] Microbial synergists (microbial nutrients) are formulated from inorganic and organic substances and a variety of additives. They utilize the organic biochemical reactions of each component to enhance microbial activity and decomposition capabilities through colloidal chemical processes, chemical reaction processes, and microbial oxidation processes. This promotes rapid microbial reproduction and domestication, increases the number of microbial populations, and maintains the stability and balance of the microbial population system, thus ensuring the high efficiency, stability, and resilience of the wastewater treatment system.

[0038] Existing methods and bioelectrochemical devices for treating recalcitrant wastewater involve anaerobic reactions under voltage conditions, promoting the synergistic effect between electrochemically active bacteria and traditional anaerobic bacteria. The anode and cathode are designed to rotate relative to the anaerobic reactor. The resulting swirling flow shortens the biofilm formation time of electrochemically active bacteria and promotes their enrichment, thus achieving synergistic removal of recalcitrant pollutants by both anode and cathode.

[0039] This invention significantly improves the pollutant degradation rate during anaerobic digestion by applying voltage during anaerobic biological treatment and by controlling the composition of microbial synergists, utilizing the synergistic effect of electrochemical technology, microbial synergists, and anaerobic reactions.

[0040] The treatment method for propylene oxide co-production methyl tert-butyl ether wastewater of the present invention includes the following steps: microbial acclimation before anaerobic biological treatment; anaerobic biological treatment of propylene oxide co-production methyl tert-butyl ether wastewater and microbial synergist at a volume ratio of (10-12):1; applying a voltage of 0.7-1.4V during the anaerobic biological treatment process; the pH during the anaerobic biological treatment process is 6.5-7.5, the temperature is 35-37℃, and the dissolved oxygen concentration is less than 0.1mg / L.

[0041] In a specific embodiment, the microbial domestication includes the following steps: under the condition of applying a constant voltage, anaerobic biological treatment is carried out on the propylene oxide co-production methyl tert-butyl ether wastewater and microbial enhancer with a volume ratio of (4-5):1. When the current drops to less than 10% of the highest current of the reaction system, more than half of the volume of the propylene oxide co-production methyl tert-butyl ether wastewater and microbial enhancer are replaced for anaerobic biological treatment. The current rises until the current shows periodic fluctuations.

[0042] In a specific implementation, the initial source of bacteria for anaerobic biological treatment comes from the anaerobic sludge in the activated sludge system of an industrial wastewater treatment plant. This sludge is rich in microbial communities and has a high capacity for organic matter degradation. Before use, the activated sludge is washed, filtered, and settled to remove inorganic impurities, particulate matter, suspended impurities, and dissolved impurities. After washing, the water is filtered out using a sieve.

[0043] In a specific embodiment, the anaerobic biological treatment is carried out in an anaerobic bioreactor. A mixed solution formed by propylene oxide co-production methyl tert-butyl ether wastewater and microbial synergists, along with anaerobic sludge, is added to the anaerobic bioreactor for anaerobic biological treatment. Voltage is applied during the anaerobic biological treatment process. The amount of anaerobic sludge added accounts for 30% to 40% of the volume of the anaerobic biological treatment reactor, and the amount of anaerobic sludge and mixed solution added accounts for 60% to 70% of the volume of the anaerobic biological treatment reactor.

[0044] It is understandable that the pH of the microbial synergist is adjusted to be 6.5-7.5. When it is added to the anaerobic reaction system with wastewater, the pH of the system will change. The pH will then be adjusted to maintain the pH of 6.5-7.5 during the anaerobic biological treatment process.

[0045] The present invention will be described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. Obviously, the following embodiments are only some examples of the present invention, and those skilled in the art can obtain other similar implementations without creative effort, all of which should be considered within the scope of protection of the present invention.

[0046] I. Specific Embodiments of the Wastewater Treatment Device for Propylene Oxide Co-production of Methyl Tert-Butyl Ether of the Present Invention

[0047] Example 1

[0048] The wastewater treatment device for the co-production of methyl tert-butyl ether from propylene oxide in this embodiment, such as... Figure 1 and Figure 2 As shown, the anaerobic biological treatment reactor 1 has an inner cavity with a length of 12cm, a width of 8cm, and a height of 8cm. The bottom wall 13 of the anaerobic biological treatment reactor 1 is provided with opposing anode plates 2 and cathode plates 3. Specifically, the bottom wall 13 of the anaerobic biological treatment reactor 1 has an anode plate holder 12 and a cathode plate holder 21, which respectively mount the anode plate 2 and the cathode plate 3. The anode plate 2 and the cathode plate 3 have a length of 2cm, a width of 5cm, and a height of 5cm, and the distance between the anode plate 2 and the cathode plate 3 is 3cm. It should be noted that the length and width of the anaerobic biological treatment reactor 1 and the anode and cathode plates are respectively... Figure 2 The length (horizontal) and width (vertical) are defined in terms of direction, and the height is defined by... Figure 1 The height (vertical) orientation is defined in the middle.

[0049] The anode plate holder 12 and the cathode plate holder 21 are connected to the positive and negative terminals of the constant voltage DC power supply 14, respectively, forming a closed loop to provide voltage and create an electric field within the reactor. The anode plate 2 is made of graphite, and the cathode plate 3 is made of titanium. The constant voltage DC power supply 14 has a voltage range of 0V to 5V and a voltage regulation accuracy of 0.01V.

[0050] The anaerobic biological treatment reactor 1 is equipped with a three-phase separation device 4 located above the anode plate 2 and the cathode plate 3, which is used to effectively separate gas, liquid and solid sludge; a gas collector 15 is provided on the upper side of the three-phase separation device 4 to collect the separated gas; the anaerobic biological treatment reactor 1 is provided with a liquid outlet 17 on the side wall of the upper part of the three-phase separation device 4 to discharge the separated liquid; the separated solid sludge settles back into the anaerobic biological treatment reactor 1 to continue the anaerobic biological reaction.

[0051] The anaerobic biological treatment reactor 1 is equipped with a stirring device, which includes a motor 5 located at the top of the reactor and a stirring shaft 7 connected to the motor 5. The stirring shaft 7 extends into the reactor 1 through a three-phase separation device 4. The portion of the stirring shaft 7 located inside the reactor 1 is uniformly equipped with stirring paddles 8. The bottom of the stirring shaft 7 extends into the sludge zone 11 to thoroughly mix the substrate and anaerobic sludge, ensuring uniform material distribution and maintaining temperature uniformity within the reactor. It should be noted that the sludge zone 11 refers to the location where the anaerobic biological reaction mainly takes place in the sludge-water mixture formed after the anaerobic sludge, wastewater, and microbial synergist are mixed, and does not refer to the sludge interface.

[0052] The anaerobic biological treatment reactor 1 has a circulating liquid inlet 19 on the side wall near the bottom wall 13 and a circulating liquid outlet 18 on the side wall near the bottom of the three-phase separation device. The circulating liquid inlet 19 and the circulating liquid outlet 18 are connected by a return pipe, and a circulation pump 20 is installed on the return pipe to return the sludge mixture in the upper part of the anaerobic biological treatment reactor 1 to the lower part. The circulating liquid inlet 19, the circulation pump 20 and the circulating liquid outlet 18 constitute the internal solution circulation within the anaerobic biological treatment reactor 1.

[0053] Inside the anaerobic biological treatment reactor 1, a pH / ORP composite probe 9 is located between the anode plate 2 and the cathode plate 3. The pH / ORP composite probe 9 is connected to a controller 10 and is used to monitor pH and ORP changes in the anaerobic biological treatment reactor 1 in real time, feeding the data back to the controller 10. The controller 10 controls the start and stop of the circulation pump 20. It is understood that the controller 10 can also control the rotational speed of the circulation pump 20 to control the flow rate of the circulating liquid.

[0054] The bottom side wall of the anaerobic biological treatment reactor 1 is provided with a discharge port 6 and a liquid inlet 16. The liquid inlet 16 is located above the discharge port 6, and the discharge port 6 is used to discharge sludge.

[0055] II. Specific Embodiments of the Method for Treating Wastewater from Propylene Oxide Co-production of Methyl Tert-Butyl Ether of the Present Invention

[0056] Example 2

[0057] The treatment method for wastewater from the co-production of methyl tert-butyl ether from propylene oxide in this embodiment is carried out in the treatment apparatus of Example 1, and the specific method is as follows:

[0058] Before the formal start-up of the treatment device, microbial acclimatization is carried out: Under anaerobic conditions, a constant voltage of 0.7V is applied between the anode plate 2 and the cathode plate 3 using a constant voltage DC power supply 14. A mixed solution of propylene oxide co-production methyl tert-butyl ether wastewater and microbial synergist in a volume ratio of 4:1 is added to the anaerobic biological treatment reactor 1, along with anaerobic sludge. The amount of anaerobic sludge added accounts for 30% of the volume of the anaerobic biological treatment reactor 1, and the total amount of anaerobic sludge and mixed solution added accounts for 70% of the volume of the anaerobic biological treatment reactor 1. This allows current to be conducted between the microorganisms in the anaerobic sludge and the electrodes. When the anode in the anaerobic biological treatment reactor 1... When the current between plate 2 and cathode plate 3 drops below 10% of the maximum current, half the volume of the mixed solution in the reactor is replaced with a mixed solution formed by propylene oxide co-production methyl tert-butyl ether wastewater and microbial synergist in equal proportions to continue promoting microbial growth and enrichment. The current increases, and as the anaerobic biological reaction proceeds, the current gradually decreases. When it drops below 10% of the maximum current, half the volume of the mixed solution in the reactor is replaced again with a mixed solution formed by propylene oxide co-production methyl tert-butyl ether wastewater and microbial synergist in equal proportions. This process is repeated until the current exhibits periodic fluctuations. Figure 3 As shown; during the acclimatization period, motor 5, three-phase separation device 4, pH / ORP composite probe 9, and circulation pump 20 are all turned on, and the speed of circulation pump 20 is 40 rpm.

[0059] The microbial synergist consists of the following components: lactic acid 2.3470 g / L, dipotassium hydrogen phosphate 0.2290 g / L, ammonium chloride 0.1660 g / L, magnesium chloride hexahydrate 0.0895 g / L, calcium chloride dihydrate 0.0251 g / L, zinc sulfate heptahydrate 0.0011 g / L, sodium bicarbonate 0.0260 g / L, ferrous sulfate heptahydrate 0.0062 g / L, fulvic acid 0.0285 g / L, manganese chloride tetrahydrate 0.0023 g / L, trace element solution 1 mL / L, and EDTA-2Na. 0.05 g / L of boric acid and water; the trace element solution consists of the following components: 0.144 g / L boric acid, 0.0368 g / L copper sulfate pentahydrate, 0.0055 g / L sodium molybdate, 0.0040 g / L nickel chloride hexahydrate, 0.0032 g / L cobalt chloride hexahydrate, and water; the pH of the microbial synergist is 6.5–7.5, which is the optimal growth range for anaerobic microorganisms, while also ensuring the activity of the EDTA chelating agent.

[0060] The preparation method of the microbial synergist is as follows: According to the above-mentioned components, dissolve lactic acid, dipotassium hydrogen phosphate, ammonium chloride, magnesium chloride hexahydrate, calcium chloride dihydrate, sodium bicarbonate, ferrous sulfate heptahydrate, humic acid, manganese chloride tetrahydrate, zinc sulfate heptahydrate, and trace element solution in an appropriate amount of deionized water to ensure complete dissolution; then add EDTA-2Na to the dissolved basic components, stir evenly, and ensure complete dissolution; finally, adjust the pH of the solution to between 6.5 and 7.5.

[0061] After the microbial domestication is completed, the treatment device is started. A mixed solution of propylene oxide co-production methyl tert-butyl ether wastewater and microbial enhancer is continuously introduced from the inlet 16 of the anaerobic biological treatment reactor 1 at a volume ratio of 10:1. The influent COD concentration is 2500-4000 mg / L and the petroleum substance concentration is 90-120 mg / L. Anaerobic sludge is used as the inoculum source.

[0062] The hydraulic retention time in anaerobic biological treatment reactor 1 is maintained at 3 days, the pH value is maintained between 6.5 and 7.5, the temperature is controlled at 35 to 37℃, and the dissolved oxygen concentration is controlled below 0.1 mg / L.

[0063] The treatment device operated for 65 days, and the experiment was divided into four stages. The applied voltage was 0.7V in the first stage, 0.9V in the second stage, 1.1V in the third stage, and 1.3V in the fourth stage. During the anaerobic biological treatment process, the pH / ORP composite probe 9 monitored the pH and ORP changes in the anaerobic biological treatment reactor 1 in real time and fed back to the controller 10. When the pH was outside the set range, the system pH was adjusted to 6.5–7.5 by adding external acids or alkalis. When the ORP was outside the set range, the ORP was stabilized by controlling the influent flow rate, etc. At the start of the treatment device operation, the controller 10 controlled the start of the circulation pump 20, which operated at 40 rpm. The treatment method for the propylene oxide co-production of methyl tert-butyl ether wastewater in this embodiment is denoted as R1.

[0064] III. Comparative Example

[0065] Comparative Example 1

[0066] The treatment method for the wastewater from the co-production of methyl tert-butyl ether from propylene oxide in this comparative example is basically the same as that in Example 2, except that no voltage is applied during the microbial acclimatization process and the start-up of the subsequent treatment device. This comparative example's treatment method is denoted as R2.

[0067] Comparative Example 2

[0068] The treatment method for the wastewater from the co-production of methyl tert-butyl ether from propylene oxide in this comparative example was carried out in the treatment apparatus of Example 1, and the specific method is as follows:

[0069] Before the treatment device is officially started, microbial domestication is carried out, and the domestication method is the same as that in Example 2. This comparative microbial synergist consists of the following components: 0.94 g / L glucose, 0.01 g / L yeast extract, 0.064 g / L HCl, 0.022 g / L KH2PO4, 0.05 g / L NaCl, 0.1 g / L EDTA-2Na, 0.075 g / L NaHCO3, 0.025 g / L MgSO4·7H2O, 0.025 g / L FeSO4·7H2O, 0.025 g / L CaCl2, 0.018 g / L FeSO4·7H2O, 0.009 g / L H3BO3, 0.16 g / L CuSO4·7H2O, 0.62 g / L MnCl2·4H2O, 0.27 g / L ZnSO4·5H2O, and 0.12 g / L NiCl2·6H2O.

[0070] After acclimatization, a mixed solution of propylene oxide co-production methyl tert-butyl ether wastewater and the microbial synergist from the comparative example was continuously introduced into the inlet 16 of the anaerobic biological treatment reactor 1 at a volume ratio of 10:1. The influent COD concentration was 2500–4000 mg / L. Anaerobic sludge was used as the inoculum source. The hydraulic retention time in the anaerobic biological treatment reactor 1 was maintained at 3 days, the pH value was maintained between 6.5 and 7.5, the temperature was controlled at 35–37℃, and the dissolved oxygen concentration was controlled below 0.1 mg / L.

[0071] The reactor operated stably for 30 days with an applied voltage of 1.3V. The results showed that when the influent concentration was 4000 mg / L, the highest COD removal rate was only 52.5%.

[0072] IV. Experimental Examples

[0073] To evaluate the treatment effect of the wastewater treatment method for the co-production of methyl tert-butyl ether from propylene oxide according to the present invention, the following key indicators were monitored periodically: COD concentration, petroleum hydrocarbon concentration, pH value, dissolved oxygen concentration, and VFAs concentration. Simultaneously, the gas composition and gas production rate collected by the gas collector 15 in the anaerobic biological treatment reactor 1 were measured periodically to examine the methane production capacity.

[0074] In the treatment of wastewater from the co-production of methyl tert-butyl ether from propylene oxide with a COD concentration of 2500–4000 mg / L, R1 showed a significantly better COD removal effect than R2. The changes in COD concentration and voltage during the four stages are shown below. Figure 4 As shown, COD in COD concentration in influent, COD ef This represents the COD concentration in the effluent.

[0075] according to Figure 4 The calculated COD removal rate and volumetric loading rate are as follows: Figure 5 As shown, from Figure 5 It can be seen that R1 achieved a maximum COD removal rate of 74.05% and an average COD removal rate of 61.89%, significantly higher than the maximum COD removal rate of 52.5% in Comparative Example 2. In contrast, R2 achieved a maximum COD removal rate of 64.99% and an average COD removal rate of 55.39%. The volumetric loading rate was gradually increased during treatment, from 0.3 kg COD / m³. 3 / d increased to 1.2KgCOD / m 3 / d.

[0076] The pH changes of the effluent after treatment using the methods of Example 2 and Comparative Example 1 at different stages are as follows: Figure 6 As shown, from Figure 6 It can be seen that the pH value of R1 is slightly higher than that of R2. The changes in VFA concentration in the effluent at different stages are shown below. Figure 7 As shown, the concentration of VFAs in the effluent of the R1 system was lower than that of the R2 system between 20 and 65 days, further indicating that the conversion of VFAs to methane in the R1 system was significantly enhanced under the action of electrochemistry.

[0077] The average concentration of petroleum hydrocarbons in the effluent from R1 was 7.8 mg / L, below 10 mg / L, meeting the Class I discharge requirements of the "Integrated Wastewater Discharge Standard." The average concentration of petroleum hydrocarbons in the effluent from R2 was 12.8 mg / L. Monitoring the gas composition and gas production rate in the gas collection system revealed that the average methane production rate in R1 was 345 mL / d / mL, significantly higher than that in R2 (220 mL / d / mL), indicating that electrochemical stimulation significantly increased the methane production in the anaerobic reactor.

[0078] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. For those skilled in the art, simple modifications or equivalent substitutions to the technical solution of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide, characterized in that, Includes the following steps: An anaerobic biological treatment process was used to treat wastewater from the co-production of methyl tert-butyl ether from propylene oxide and a microbial synergist, with voltage applied during the process. The microbial synergist included lactic acid, dipotassium hydrogen phosphate, ammonium chloride, magnesium chloride, calcium chloride, zinc sulfate, sodium bicarbonate, ferrous sulfate, fulvic acid, manganese chloride, EDTA-2Na, and trace elements, including boric acid, copper sulfate, sodium molybdate, nickel chloride, and cobalt chloride. The voltage was applied in four stages during the anaerobic biological treatment process: 0.7–0.8 V in the first stage, 0.9–1.0 V in the second stage, 1.1–1.2 V in the third stage, and 1.3–1.4 V in the fourth stage.

2. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 1, characterized in that, The microbial synergist comprises the following components: lactic acid 2-2.5 g / L, dipotassium hydrogen phosphate 0.2-0.255 g / L, ammonium chloride 0.15-0.2 g / L, magnesium chloride hexahydrate 0.08-0.1 g / L, calcium chloride dihydrate 0.02-0.05 g / L, zinc sulfate heptahydrate 0.001-0.005 g / L, sodium bicarbonate 0.02-0.05 g / L, ferrous sulfate heptahydrate 0.005-0.010 g / L, fulvic acid 0.02-0.05 g / L, manganese chloride tetrahydrate 0.002-0.005 g / L, trace element solution 1-5 mL / L, and EDTA-2Na. The trace element solution comprises the following components: boric acid 0.1-0.15 g / L, copper sulfate pentahydrate 0.03-0.05 g / L, sodium molybdate 0.005-0.010 g / L, nickel chloride hexahydrate 0.004-0.005 g / L, cobalt chloride hexahydrate 0.003-0.005 g / L, and water; the pH of the microbial synergist is 6.5-7.

5.

3. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 1 or 2, characterized in that, In the anaerobic biological treatment process, the volume ratio of propylene oxide co-production methyl tert-butyl ether wastewater to microbial synergist is (10~12):

1.

4. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 1, characterized in that, The anaerobic biological treatment process is characterized by a pH of 6.5–7.5, a temperature of 35–37°C, and a dissolved oxygen concentration of less than 0.1 mg / L.

5. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 1, characterized in that, Before anaerobic biological treatment, microbial domestication is carried out, which includes the following steps: under the condition of applying voltage, anaerobic biological treatment is carried out on propylene oxide co-production methyl tert-butyl ether wastewater and microbial enhancer in a volume ratio of (4~5):1 until the current drops to less than 10% of the highest current of the reaction system, and then the propylene oxide co-production methyl tert-butyl ether wastewater and microbial enhancer are renewed and anaerobic biological treatment is carried out until the current stabilizes.

6. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 1, characterized in that, The anaerobic biological treatment is carried out in an anaerobic biological treatment reactor. The bottom wall of the anaerobic biological treatment reactor is provided with an anode plate and a cathode plate extending towards the top of the anaerobic biological treatment reactor. The anode plate and the cathode plate are arranged at intervals.

7. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 6, characterized in that, The anaerobic biological treatment reactor has a three-phase separation device located above the anode plate and cathode plate.

8. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 7, characterized in that, The anaerobic biological treatment reactor has a circulating liquid outlet on the side wall located below the three-phase separation device, and a circulating liquid inlet on the side wall near the bottom wall. The circulating liquid outlet and the circulating liquid inlet are connected by a reflux pipe, and a circulating pump is installed on the reflux pipe.

9. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 6, characterized in that, The anaerobic biological treatment reactor is equipped with a stirring device for stirring the materials inside the reactor.

10. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 7, characterized in that, The anaerobic biological treatment reactor is equipped with a gas collector at the top to collect the gas separated by the three-phase separation device. The anaerobic biological treatment reactor has a liquid outlet on the side wall near the top of the three-phase separation device.

11. The method for treating wastewater from the co-production of methyl tert-butyl ether from propylene oxide as described in claim 6, characterized in that, A pH / ORP composite probe is installed between the spaced-anode and cathode plates to monitor the system pH and redox potential during the anaerobic biological reaction process.

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