Method for treating oil and gas field pressure return fluid by multifunctional mycelium pellet-enhanced aerobic granular sludge

Abstract

The invention discloses a method for treating oil and gas field pressure return fluid by using multifunctional mycelial pellets to strengthen aerobic granular sludge, the method comprising the following steps: 1) inoculating fungal strains, culturing and washing to obtain a fungal spore suspension after maturity; 2) inoculating the fungal spore suspension in a culture medium, culturing and obtaining a multifunctional mycelial pellet; 3) inoculating the multifunctional mycelial pellet in a reactor; 4) introducing wastewater into the reactor, operating the reactor in a batch mode to treat the wastewater, culturing and obtaining the multifunctional mycelial pellet-strengthened aerobic granular sludge; wherein the fungi include at least one of Aspergillus polydorum and Cladosporium maxima. The invention can achieve efficient removal of pollutants in oil and gas field pressure return fluid in a green and economical manner.

Description

Technical Field

[0001] The invention relates to the technical field of biological sewage treatment, and in particular to a method for treating oil and gas field pressure return fluid by using multifunctional mycelium balls to strengthen aerobic granular sludge. Background Art

[0002] Hydraulic fracturing is crucial to the increase in production and development of oil and gas wells. During the production process after fracturing, the injected fracturing fluid will flow back to the surface. Under certain working conditions, it will be mixed with substances or formation water that have seeped into the formation. This type of wastewater is collectively referred to as oil and gas field fracturing flowback fluid (or "fracturing flowback fluid"). The fracturing flowback fluid contains high concentrations of suspended matter and organic matter (such as large molecular organic matter such as polyacrylamide and guar gum, as well as small molecular organic matter such as aromatic hydrocarbons and long-chain hydrocarbons), as well as certain salt ions. If improperly handled, it will cause great harm to the ecological environment and human health.

[0003] Traditional physical and chemical methods such as physical adsorption and chemical oxidation (e.g. electrocatalytic oxidation, Fenton oxidation, ozone catalytic oxidation) are not only costly and energy-intensive to treat organic matter in shale gas produced water, but also sometimes cause secondary pollution. In contrast, biological treatment has the advantages of low cost and environmental friendliness. However, the general activated sludge method is prone to problems such as sludge floating when faced with a high salinity environment, and the microorganisms in the sludge have limited ability to degrade the difficult-to-degrade organic matter in it.

[0004] The general filamentous fungus mycelium pellets as carriers do not have the ability to degrade organic pollutants. At the same time, their salinity tolerance is also limited, and they cannot be used in high-salinity environments (for example, salinity above 5%). They are often quickly replaced by other microorganisms after inoculation, and it is difficult to continue to play a role, resulting in problems such as substandard effluent during the startup period and poor granular sludge cultivation effects. In addition, the removal of organic matter in oil and gas field pressure return fluids only relies on the functional microorganisms in the activated sludge, and the treatment load is limited. It cannot be started under high organic loads, and the pollutant removal rate in the early stage of granular sludge cultivation is low, and the effluent does not meet the standards. For example, Aspergillus niger, Aspergillus tubingensis, Phoma spp., Penicillium citrinum, Aspergillus nidulans, and Phanerochaete chrysosporium are not suitable for degrading organic matter in oil and gas field pressure return fluids.

[0005] For example, the prior art application number is 202111263435.1, entitled "A method for rapid cultivation of aerobic granular sludge for treating high-salinity wastewater", which induces the formation of mycelial balls by adding a sugar carbon source in the early stage, accelerates the start-up of salt-tolerant aerobic granular sludge, and cultivates aerobic granular sludge that tolerates high salinity at low cost and quickly. This prior art induces mycelial balls by adding a carbon source, but there is a problem of poor repeatability of mycelial ball species. At the same time, since only sludge is added in the early stage of the reaction, it is difficult to achieve efficient removal of pollutants in the oil and gas field pressure return liquid, and sludge floating, loss and other problems are prone to occur.

[0006] At present, the slow particle formation of aerobic granular sludge and the poor wastewater treatment effect during the startup period are bottleneck problems that plague its industrial application. Summary of the invention

[0007] In view of the problems existing in the prior art, in the first aspect, the purpose of the present invention is to provide a multifunctional mycelial pellet-enhanced aerobic granular sludge. In the second aspect, the purpose of the present invention is to provide a method for treating oil and gas field pressure return fluid with a multifunctional mycelial pellet-enhanced aerobic granular sludge. The present invention adopts a multifunctional mycelial pellet inoculation strategy, which not only has the ability to accelerate the cultivation of aerobic granular sludge, but the multifunctional mycelial pellet can also tolerate a wide range of salinity and degrade organic matter in oil and gas field pressure return fluid, which can achieve efficient removal of pollutants during the system startup period and can be started under high organic load.

[0008] The present invention adopts the following technical solutions:

[0009] In a first aspect, the present application provides a multifunctional mycelial ball and a multifunctional mycelial ball enhanced aerobic granular sludge, wherein the multifunctional mycelial ball is prepared by a method including or consisting of the following steps 1) and 2), and the multifunctional mycelial ball enhanced aerobic granular sludge is prepared by a method including or consisting of the following steps 1) to 4):

[0010] 1) inoculating the fungal strain, optionally, for example, the fungal strain is placed on a solid culture medium, for example, a (multifunctional) fungal strain can be inoculated on a slant of potato dextrose agar (PDA), and after culturing to maturity, washing is performed to obtain a fungal spore suspension; optionally, the washing method can be water washing, preferably, the water is at least one of deionized water, distilled water, double distilled water, ultrapure water, and sterile water;

[0011] As an example and not a limitation, a glycerol tube containing a (multifunctional) fungal strain is taken out of a -80°C freezer, streaked on a sterile potato dextrose agar (PDA) medium slant using an inoculating loop, and the streaked slant is placed in an incubator at about 30°C for about 7 days. The spores on the slant are washed into sterile physiological saline in a clean bench to prepare a spore suspension, and the number of spores per milliliter of the spore suspension is counted under a microscope using a hemocytometer.

[0012] 2) inoculating the fungal spore suspension into a culture medium to culture and obtain multifunctional mycelial balls;

[0013] By way of example and not limitation, a fungal spore suspension is inoculated into a shake flask containing sterile culture medium at an inoculum level of, for example, 10 3spores / mL culture solution. The sterile culture medium is optionally composed of 10 g / L anhydrous glucose, 1 g / L NH4Cl, 0.72 g / L KH2PO4, 0.5 g / L MgSO4·7H2O and 30 g / L NaCl, and deionized water is added to make the volume to 1 L, and then sterilized to obtain the obtained product. The shake flask inoculated with the spore suspension is placed in a shaker, for example, at 25°C and 200 rpm for 144 hours to obtain a mycelial ball.

[0014] 3) inoculating the multifunctional mycelial pellet in a reactor; for example, the reactor is a wastewater treatment reactor;

[0015] 4) introducing wastewater into the reactor, operating the reactor in a batch mode to treat the wastewater, and cultivating and obtaining the multifunctional mycelium pellet-enhanced aerobic granular sludge;

[0016] The fungus comprises at least one of Aspergillus polydorum and Cladosporium exigua; the fungus consists of at least one of Aspergillus polydorum and Cladosporium exigua. For example, the fungus is Aspergillus polydorum; alternatively, the fungus is Cladosporium exigua.

[0017] In this paper, (multifunctional) fungi have the ability to degrade organic matter in oil and gas field return fluids, and also have the ability to form pellets and tolerate a wide range of salinity.

[0018] Without wishing to be bound by theory, in some feasible embodiments, the name of the Aspergillus sydowii is Aspergillus sydowii NXY1, which was deposited in the China General Microbiology Center (CGMCC) on June 17, 2022, with a deposit number of CGMCC No: 40215.

[0019] Without wishing to be bound by theory, in some feasible embodiments, the name of the Cladosporium tenuissimum is Cladosporium tenuissimum NXY8, which was deposited in the China General Microbiology Center (CGMCC) on March 4, 2022, with a deposit number of CGMCC No: 40141.

[0020] In combination with the first aspect, in some feasible embodiments, the shape of the multifunctional mycelium ball includes but is not limited to at least one of a sphere, an ellipsoid, a rugby ball, a radial sphere, and an irregular sphere.

[0021] In conjunction with the first aspect, in some feasible embodiments, the salinity tolerance of the fungus is 1 g / L to 100 g / L in terms of sodium chloride, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 98, 99, 100 g / L, etc., but are not limited to the listed values, and other values ​​or ranges not listed within the numerical range are also applicable.

[0022] In combination with the first aspect, in some alternative embodiments, the fungus can tolerate a salinity range of up to 10%, for example up to 9%, up to 8%, up to 7%, up to 6%, for example 5%, 4%, 3%, 2%, 1%, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are equally applicable.

[0023] In conjunction with the first aspect, in some feasible embodiments, the salinity tolerance of the fungus is measured by conductivity (for example, measured at 25° C. using a conductivity meter) of 2 mS / cm to 170 mS / cm, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52 , 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 110, 120, 130, 140, 150, 160, 170 mS / cm, etc., but are not limited to the listed values, and other values ​​or ranges not listed within the numerical range are also applicable.

[0024] In combination with the first aspect, in some feasible embodiments, in step 2), the culture medium is a liquid culture medium.

[0025] In combination with the first aspect, in some feasible embodiments, in step 2), the culture medium contains or consists of the following items: 5g / L to 80g / L glucose, 0.5g / L to 8g / L NH4Cl, 0.3g / L to 6g / L KH2PO4, 0.25g / L to 4g / LMgSO4·7H2O, 0g / L to 80g / LNaCl; optionally, the glucose is anhydrous glucose.

[0026] In combination with the first aspect, in some feasible embodiments, in step 2), the culture medium contains or consists of the following items: 5g / L to 80g / L glucose, 0.5g / L to 8g / L NH4Cl, 0.3g / L to 6g / L KH2PO4, 0.25g / L to 4g / LMgSO4·7H2O, 0g / L to 80g / LNaCl, and water is added to make the volume to 1L; optionally, the glucose is anhydrous glucose.

[0027] In combination with the first aspect, in some feasible embodiments, in step 2), the culture medium is prepared after high-pressure sterilization.

[0028] In combination with the first aspect, in some feasible embodiments, in step 2), the inoculation amount of fungal spores is 1×10 2 Up to 1×10 7 spores / mL medium, for example, about 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 , 1×10 7 spores / mL culture medium, etc., but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0029] In combination with the first aspect, in some feasible embodiments, in step 2), the inoculation amount of fungal spores is 1×10 2 Up to 1×10 7 spores / g medium, for example, about 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 , 1×10 7 spores / g culture medium, etc., but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0030] In combination with the first aspect, in some feasible embodiments, in step 2), the culture conditions of the multifunctional mycelial ball are 15°C to 35°C, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35°C, and the like, but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0031] In combination with the first aspect, in some feasible embodiments, in step 2), the culture conditions of the multifunctional mycelial ball are 60rpm to 400rpm, for example, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400rpm, and the like, but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are equally applicable.

[0032] In combination with the first aspect, in some feasible embodiments, in step 2), the culture conditions of the multifunctional mycelium ball are constant temperature culture for 20 to 240 hours, for example, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 hours, and the like, but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0033] In combination with the first aspect, in some feasible embodiments, in step 3), the inoculation amount of the multifunctional mycelium ball is 0.1g / L to 10g / L, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10g / L, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0034] In combination with the first aspect, in some feasible embodiments, in step 3), the multifunctional mycelial balls and activated sludge are inoculated in the reactor; the mass ratio of the activated sludge to the multifunctional mycelial balls is 0 to 90:1, for example 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0035] In combination with the first aspect, in some feasible implementation schemes, in step 4), the sequencing batch operation process includes water inlet, aeration, static sedimentation, water outlet and idle stages.

[0036] In combination with the first aspect, in some feasible implementation schemes, in step 4), the total time of each operation cycle of the batch operation is 1 hour to 24 hours, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0037] In combination with the first aspect, in some feasible embodiments, in step 4), the pH of the reaction system is maintained at 5 to 9 during batch operation, for example 5, 6, 7, 8, 9, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0038] In combination with the first aspect, in some feasible embodiments, in step 4), the reaction temperature during batch operation is maintained at 15°C to 35°C, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35°C, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0039] In combination with the first aspect, in some feasible embodiments, in step 4), the volume exchange rate per cycle during batch operation is maintained at 30% to 80%, for example, 30%, 40%, 50%, 60%, 70%, 80%, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0040] In combination with the first aspect, in some feasible implementation schemes, in step 4), during the aeration stage of sequencing batch operation, air enters from the bottom, and the superficial gas velocity (the ratio of air flow rate to the cross-sectional area in the reactor) is maintained at 0.1 cm / s to 4.5 cm / s, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 4.5 cm / s; the dissolved oxygen concentration is controlled at 2 mg / L to 10 mg / L, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10 mg / L, etc., but is not limited to the listed values, and other values ​​or ranges not listed within the numerical range are equally applicable.

[0041] In combination with the first aspect, in some feasible implementation schemes, in step 4), the time range of the static sedimentation stage during batch operation is 0.1 min to 30 min, for example, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 min, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are equally applicable.

[0042] In combination with the first aspect, in some feasible implementation schemes, in step 4), the organic load range of the reaction system during batch operation is 0.3 kg COD / (m 3 ·day) to 25kg COD / (m 3 ·day), for example 0.3, 0.5, 0.8, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 kg COD / (m 3 ·days), etc., but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0043] In combination with the first aspect, in some feasible implementation schemes, the wastewater is oil and gas field pressure return fluid, and the source of the oil and gas field pressure return fluid includes or consists of at least one of the following items: oil field pressure return fluid, natural gas field produced water, shale gas pressure return fluid, shale gas produced water, and tight gas produced water.

[0044] In combination with the first aspect, in some feasible embodiments, the wastewater is oil and gas field pressure return fluid, and the oil and gas field pressure return fluid contains or consists of the following items: polyacrylamide, guar gum, isopropanol, ethylene glycol, hydrocarbons, heterocyclic compounds, phenol, aniline, petroleum and at least one of their derivatives; optionally, the hydrocarbons contain at least one of polycyclic aromatic hydrocarbons, alkylbenzenes, aliphatic hydrocarbons and their derivatives.

[0045] In a second aspect, the present application provides a method for treating oil and gas field pressure return fluid by using multifunctional mycelial balls to enhance aerobic granular sludge, comprising the following steps:

[0046] 1) inoculating the fungal strain, optionally, for example, the fungal strain is placed on a solid culture medium, for example, a (multifunctional) fungal strain can be inoculated on a slant of potato dextrose agar (PDA), and after culturing to maturity, washing is performed to obtain a fungal spore suspension; optionally, the washing method can be water washing, preferably, the water is at least one of deionized water, distilled water, double distilled water, ultrapure water, and sterile water;

[0047] As an example and not a limitation, a glycerol tube containing a (multifunctional) fungal strain is taken out of a -80°C freezer, streaked on a sterile potato dextrose agar (PDA) medium slant using an inoculating loop, and the streaked slant is placed in an incubator at about 30°C for about 7 days. The spores on the slant are washed into sterile physiological saline in a clean bench to prepare a spore suspension, and the number of spores per milliliter of the spore suspension is counted under a microscope using a hemocytometer.

[0048] 2) inoculating the fungal spore suspension into a culture medium to culture and obtain multifunctional mycelial balls;

[0049] 3) inoculating the multifunctional mycelial pellet in a reactor; for example, the reactor is a wastewater treatment reactor;

[0050] 4) introducing wastewater into the reactor, operating the reactor in a sequencing batch mode to culture and treat the wastewater and obtain multifunctional mycelial pellet-enhanced aerobic granular sludge, wherein the wastewater is oil and gas field return fluid, and the aerobic granular sludge cultured in the sequencing batch mode reactor simultaneously treats the oil and gas field return fluid;

[0051] The fungus comprises at least one of Aspergillus polydorum and Cladosporium exigua; the fungus consists of at least one of Aspergillus polydorum and Cladosporium exigua. For example, the fungus is Aspergillus polydorum; alternatively, the fungus is Cladosporium exigua.

[0052] In combination with the second aspect, in some feasible embodiments, the name of the Aspergillus sydowii is Aspergillus sydowii NXY1, and the preservation number is CGMCC No: 40215; and / or, the name of the Cladosporium tenuissimum is Cladosporium tenuissimum NXY8, and the preservation number is CGMCC No: 40141.

[0053] In combination with the second aspect, in some feasible embodiments, the shape of the multifunctional mycelium ball includes at least one of a sphere, an ellipsoid, a rugby ball, a radial sphere, and an irregular sphere.

[0054] In conjunction with the second aspect, in some feasible embodiments, the salinity tolerance of the fungus is 1 g / L to 100 g / L in terms of sodium chloride, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 98, 99, 100 g / L, etc., but are not limited to the listed values, and other values ​​or ranges not listed within the numerical range are also applicable.

[0055] In combination with the second aspect, in some alternative embodiments, the fungus can tolerate a salinity range of 10%, for example up to 9%, up to 8%, up to 7%, up to 6%, for example 5%, 4%, 3%, 2%, 1%, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are equally applicable.

[0056] In conjunction with the second aspect, in some feasible embodiments, the salinity tolerance of the fungus is measured by conductivity (for example, measured at 25° C. using a conductivity meter) of 2 mS / cm to 170 mS / cm, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52 , 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 110, 120, 130, 140, 150, 160, 170 mS / cm, etc., but are not limited to the listed values, and other values ​​or ranges not listed within the numerical range are also applicable.

[0057] In conjunction with the second aspect, in some feasible embodiments, in step 2), the culture medium is a liquid culture medium.

[0058] In combination with the second aspect, in some feasible embodiments, in step 2), the culture medium contains or consists of the following items: 5g / L to 80g / L glucose, 0.5g / L to 8g / L NH4Cl, 0.3g / L to 6g / L KH2PO4, 0.25g / L to 4g / LMgSO4·7H2O, 0g / L to 80g / LNaCl; optionally, the glucose is anhydrous glucose.

[0059] In combination with the second aspect, in some feasible embodiments, in step 2), the culture medium contains or consists of the following items: 5g / L to 80g / L glucose, 0.5g / L to 8g / L NH4Cl, 0.3g / L to 6g / L KH2PO4, 0.25g / L to 4g / LMgSO4·7H2O, 0g / L to 80g / LNaCl, and water is added to make up to 1L; optionally, the glucose is anhydrous glucose.

[0060] In combination with the second aspect, in some feasible embodiments, in step 2), the culture medium is prepared after high-pressure sterilization.

[0061] In conjunction with the second aspect, in some feasible embodiments, in step 2), the inoculation amount of fungal spores is 1×10 2 Up to 1×107 spores / mL medium, for example, about 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 , 1×10 7 spores / mL culture medium, etc., but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0062] In conjunction with the second aspect, in some feasible embodiments, in step 2), the inoculation amount of fungal spores is 1×10 2 Up to 1×10 7 spores / g medium, for example, about 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 , 1×10 7 spores / g culture medium, etc., but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0063] In combination with the second aspect, in some feasible embodiments, in step 2), the culture conditions of the multifunctional mycelial ball are 15°C to 35°C, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35°C, and the like, but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0064] In combination with the second aspect, in some feasible embodiments, in step 2), the culture conditions of the multifunctional mycelial ball are 60rpm to 400rpm, for example, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400rpm, and the like, but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are equally applicable.

[0065] In combination with the second aspect, in some feasible embodiments, in step 2), the culture conditions of the multifunctional mycelium ball are constant temperature culture for 20 to 240 hours, for example, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 hours, and the like, but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0066] In combination with the second aspect, in some feasible embodiments, in step 3), the inoculation amount of the multifunctional mycelium ball is 0.1g / L to 10g / L, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10g / L, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0067] In combination with the second aspect, in some feasible embodiments, in step 3), the multifunctional mycelial balls and activated sludge are inoculated in the reactor; the mass ratio of the activated sludge to the multifunctional mycelial balls is 0 to 90:1, for example 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0068] In combination with the second aspect, in some feasible implementation schemes, in step 4), the sequencing batch operation process includes water inlet, aeration, static sedimentation, water outlet and idle stages.

[0069] In combination with the second aspect, in some feasible implementation schemes, in step 4), the total time of each operation cycle of the batch operation is 1 hour to 24 hours, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0070] In combination with the second aspect, in some feasible embodiments, in step 4), the pH of the reaction system is maintained at 5 to 9 during batch operation, for example, 5, 6, 7, 8, 9, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0071] In combination with the second aspect, in some feasible embodiments, in step 4), the reaction temperature during batch operation is maintained at 15°C to 35°C, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35°C, and the like, but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0072] In combination with the second aspect, in some feasible embodiments, in step 4), the volume exchange rate per cycle during batch operation is maintained at 30% to 80%, for example, 30%, 40%, 50%, 60%, 70%, 80%, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0073] In combination with the second aspect, in some feasible implementation schemes, in step 4), during the aeration stage of sequencing batch operation, air enters from the bottom, and the superficial gas velocity (the ratio of air flow rate to the cross-sectional area in the reactor) is maintained at 0.1 cm / s to 4.5 cm / s, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 4.5 cm / s; the dissolved oxygen concentration is controlled at 2 mg / L to 10 mg / L, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10 mg / L, etc., but is not limited to the listed values, and other values ​​or ranges not listed within the numerical range are equally applicable.

[0074] In combination with the second aspect, in some feasible implementation schemes, in step 4), the time range of the static sedimentation stage during batch operation is 0.1 min to 30 min, for example, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 min, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are equally applicable.

[0075] In combination with the second aspect, in some feasible implementation schemes, in step 4), the organic load range of the reaction system during batch operation is 0.3 kg COD / (m 3 ·day) to 25kg COD / (m 3 ·day), for example 0.3, 0.5, 0.8, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 kg COD / (m 3·days), etc., but are not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0076] In combination with the second aspect, in some feasible implementation schemes, the wastewater is oil and gas field pressure return fluid, and the source of the oil and gas field pressure return fluid includes or consists of at least one of the following items: oil field pressure return fluid, natural gas field produced water, shale gas pressure return fluid, shale gas produced water, and tight gas produced water.

[0077] In combination with the second aspect, in some feasible embodiments, the wastewater is oil and gas field pressure return fluid, and the oil and gas field pressure return fluid contains or consists of the following items: polyacrylamide, guar gum, isopropyl alcohol, ethylene glycol, hydrocarbons, heterocyclic compounds, phenol, aniline, petroleum and at least one of their derivatives; optionally, the hydrocarbons contain at least one of polycyclic aromatic hydrocarbons, alkylbenzenes, aliphatic hydrocarbons and their derivatives.

[0078] As used herein, the term "fracturing flowback fluid" may be used interchangeably with "frac flowback fluid."

[0079] The term "shale gas produced water" as used in this article includes a large number of chemical additives from fracturing fluids, such as gelling agents, drag reducers, cross-linking agents, bactericides and surfactants, as well as metal ions and organic substances such as alkanes and aromatic hydrocarbons from the formation.

[0080] As used herein, the term "organic load" refers to the amount of organic pollutants accepted by a unit volume of wastewater treatment reactor per unit time, generally excluding organic matter in the reactor reflux (when a reflux system is used). Organic matter can be expressed as COD, so it is also called COD load, with a unit of kg / (m 3 ·day). In the field of sewage treatment, load represents the capacity of sewage treatment facilities to receive sewage. In other words, organic load is an indicator of the treatment capacity of sewage treatment facilities.

[0081] As used herein, the term "aerobic granular sludge (AGS)" refers to a densely structured bioaggregate formed by self-agglomeration of microorganisms in sludge under an aerobic environment. Compared with ordinary activated sludge, aerobic granular sludge has the characteristics of being less prone to sludge swelling, strong impact resistance, able to withstand high organic loads, and integrating microorganisms of different properties (aerobic, facultative anerobic and anaerobic microorganisms).

[0082] As used herein, the term "mycelium ball" refers to a sphere formed by the self-entanglement of filamentous fungi, which has a large number of mutually entangled hyphae, so even without adding chemical agents for flocculation, it can gather particulate matter and functional bacterial flora in the environment through the capture effect between cells and the electrostatic adsorption effect of surface charges. Mycelium balls have the characteristics of large specific surface area, excellent adsorption performance, fast sedimentation rate, conducive to solid-liquid separation, high biocompatibility, and no secondary pollution.

[0083] The method for determining the particle size of mycelial balls was as follows: 30 mycelial balls were randomly selected, photographed, and the diameters of the mycelial balls were measured using image processing software (ImageJ.JS, v0.5.5). The average value was taken as the average particle size of the mycelial balls.

[0084] As used herein, the term "Sequencing Batch Reactor (SBR)" refers to a reactor that operates intermittently in a time sequence, which is characterized by complete mixing in space and alternating in time, and the entire treatment process (including phosphorus removal and denitrification process) is carried out in the same reactor.

[0085] The aerobic granular sludge in this application shows great potential to replace traditional activated sludge technology: (1) Granular sludge has excellent sedimentation performance, which can save the secondary sedimentation tank with a large footprint and the return facilities with huge energy consumption; (2) Aerobic granular sludge has a dense structure, so this technology has the advantages of high sludge content, strong sludge retention capacity, and strong resistance to stress (such as salinity, toxic substances, water quality fluctuations, etc.); (3) Aerobic granular sludge has a hierarchical structure, with the inner core being the anaerobic / anoxic zone and the outer layer being the aerobic zone, which gives different microorganisms a suitable ecological niche, allowing multiple biological reactions such as biological oxidation, nitrification, denitrification, and phosphorus accumulation to be carried out in the same granule.

[0086] The mycelial pellets in this application have the advantages of fast sedimentation speed, easy solid-liquid separation, high biological activity, strong adsorption capacity for pollutants, and the ability to secrete a variety of enzymes. Adding mycelial pellets to activated sludge can serve as a core carrier to provide space for microorganisms to adsorb and grow, promote the aggregation of microorganisms, and thus accelerate the formation of granular sludge.

[0087] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range of instrument control.

[0088] Compared with the prior art, the present invention has the following beneficial effects:

[0089] (1) Compared with the prior art, the mycelium balls used in the present invention are multifunctional mycelium balls, which have the ability to degrade organic matter in shale gas pressure return liquid, can release extracellular enzymes to degrade or metabolize organic matter in shale gas pressure return liquid by themselves, and increase the processing load of the reaction system. At the same time, the mycelium structure can provide a skeleton for other microorganisms, increase the residence time of other functional microorganisms, and avoid being discharged with the effluent. In addition, the mycelium ball structure can better improve the sedimentation performance of sludge, reduce the construction of secondary sedimentation tanks, and significantly accelerate sludge granulation. After forming aerobic granular sludge, it can simultaneously remove nitrogen and carbon with more excellent performance;

[0090] (2) Compared with the prior art, the present invention has lower requirements on the properties of the initial activated sludge, thus avoiding the trouble caused by the different properties of inoculated sludge in different places and improving the controllability of industrial application;

[0091] (3) Compared with the prior art, the mycelium pellets used in the present invention are multifunctional mycelium pellets. The multifunctional mycelium pellets with pollutant removal ability are directly added in the early stage of the reactor startup, thereby avoiding the problem of low organic matter and ammonia nitrogen removal rate caused by the activated sludge not being able to adapt to the oil and gas field pressure return liquid in the early stage of the reactor startup, thereby ensuring the effluent quality;

[0092] (4) Compared with the prior art, the present invention can achieve efficient removal of pollutants in oil and gas field return fluid in an environmentally friendly and economical manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 The Aspergillus polymorpha mycelial pellet formed in Example 1 is shown;

[0094] Figure 2 shows the aerobic granular sludge formed in Example 1;

[0095] Figure 3 The aerobic granular sludge formed in Comparative Example 1 is shown. DETAILED DESCRIPTION

[0096] In order to better explain the present invention, the embodiments of the present application will be described in detail below in conjunction with specific examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. The specific conditions not specified in the examples are carried out according to the conditions recommended by normal conditions or manufacturers. The reagents used or the instruments not specified by the manufacturer are all conventional products that can be obtained by commercial purchase.

[0097] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. It is further understood that terms, such as defined in commonly used dictionaries, are interpreted in accordance with their meanings in the context of the relevant art and are not in an idealized or overly formal sense unless explicitly so defined herein.

[0098] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

[0099] Unless otherwise indicated, the use of any and all examples or exemplary language (such as "for example") provided herein is intended only to better illustrate the invention and is not intended to limit the scope of the invention. Unless expressly stated otherwise, no language in the specification should be construed as indicating that any element is essential to the implementation of the invention.

[0100] As used in this application, the term "about" is used to describe and illustrate small changes. When used in conjunction with an event or situation, the term may refer to an example in which the event or situation occurs precisely and an example in which the event or situation occurs very approximately. For example, when used in conjunction with a numerical value, the term may refer to a range of variation of less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. In addition, amounts, ratios, and other numerical values ​​are sometimes presented in the present application in a range format. It should be understood that such a range format is for convenience and simplicity, and should be flexibly understood to include not only numerical values ​​explicitly designated as range limits, but also all individual numerical values ​​or subranges encompassed within the range, as if each numerical value and subrange were explicitly designated.

[0101] The exemplary invention described herein may appropriately lack any one or more element limitations that are not specifically disclosed herein. Therefore, the terms "comprise", "include", "contain", etc. should be understood broadly and non-restrictively. In addition, the terminology used herein is used as a description, not a limitation, and it is unintentional to use these terminology expressions that do not include any equivalent characteristics, but only describe some of their characteristics, but various modifications are possible within the scope of the present invention according to the rights. Therefore, although the present invention has been specifically disclosed by preferred embodiments and optional features, the modifications disclosed herein to embody the changes of the present invention may be recorded by those skilled in the art, and such modifications and changes will be considered to be within the scope of the present invention.

[0102] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0103] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0104] When amount, concentration or other value or parameter is represented by range, preferred range or a series of upper preferred value and lower preferred value, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1 to 10", described range should be interpreted as including range "1 to 10", "1 to 9", "1 to 8", "1 to 7", "1 to 6", "1 to 5", "1 to 4", "1 to 3", "1 to 2", "1 to 3 and 5 to 10", "1 to 4 and 8" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0105] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0106] In addition, the terms "first" and "second" used in this article are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the embodiments of the present disclosure, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0107] Example 1

[0108] Method for treating oil and gas field return fluid with multifunctional mycelium balls enhanced aerobic granular sludge:

[0109] 1) Inoculate Aspergillus sydowii with the ability to degrade organic matter in shale gas pressure return fluid on the PDA slant, and wash with deionized water to obtain a spore suspension of mature Aspergillus sydowii. The Aspergillus sydowii used was isolated from the shale gas pressure return fluid and was deposited in the General Microbiology Center of the China Microbiological Collection Administration (CGMCC) on June 17, 2022, with a deposit number of CGMCC No: 40215;

[0110] 2) Inoculate a suspension of Aspergillus polyspores in a liquid culture medium to culture a multifunctional mycelium pellet, wherein the liquid culture medium is composed of 10 g / L anhydrous glucose, 1 g / L NH4Cl, 0.7 g / L KH2PO4, 0.5 g / L MgSO4·7H2O and 30 g / L NaCl, add deionized water to a volume of 1 L, and then sterilize by high pressure. The spore inoculation amount is 10 5 spores / mL culture medium, the mycelial pellet culture conditions are 30℃, 160rpm shaker constant temperature culture for 120h. The mycelial pellets formed are white spherical, Figure 1 The Aspergillus polymorpha mycelial pellets formed in Example 1 have an average diameter of 1680 μm and an average sedimentation velocity of 1.15 cm / s in a 30 g / L NaCl solution;

[0111] 3) Inoculating 1 g / L of Aspergillus polymorpha pellets and 3 g / L of activated sludge in a wastewater treatment reactor;

[0112] 4) The simulated shale gas pressure return liquid (salinity of 3%, COD concentration of 850 mg / L) was treated by culturing aerobic granular sludge in a sequencing batch reactor. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The simulated shale gas pressure return liquid was prepared by adding tap water to 1L, which contained 200 mg / L polyacrylamide, 220 mg / L isopropanol, 100 mg / L guar gum, 25 mg / L ethylene glycol, 40 mg / L n-hexadecane, 20 mg / L phenol, 30 mg / L aniline, 40 mg / L CaCl2, 37 mg / L MgSO4·7H2O, 37 mg / L FeSO4·7H2O and 30 g / L NaCl. The total time of each operation cycle in the batch operation is 6 hours. The pH of the reaction system is maintained at 7-8, the temperature is maintained at 20℃-25℃, the volume exchange rate of each cycle is 60%, the air enters from the bottom during the aeration stage, the superficial gas velocity is maintained at 1.2cm / s, and the static sedimentation time is 5min. The organic load of the reaction system is 2.04kg COD / (m 3 ·sky).

[0113] Aerobic granular sludge was formed on the 16th day, and the average particle size of aerobic granular sludge was 870 μm. Figure 2 The aerobic granular sludge formed in Example 1 is shown. The start-up period of aerobic granular sludge is 1-16 days, that is, it starts to form on the 1st day and is completely formed on the 16th day. According to experimental measurements, the average organic matter removal rate in Example 1 is 56.8%, the average polyacrylamide removal rate is 18.4%, and the average isopropanol removal rate is 82.9%; the organic matter removal rate gradually increases to 71.0% on the 17th to 22nd day and remains stable.

[0114] Example 2

[0115] Method for treating oil and gas field return fluid with multifunctional mycelium balls enhanced aerobic granular sludge:

[0116] 1) The PDA slant was inoculated with Cladosporium tenuissimum, which has the ability to degrade organic matter in shale gas pressure return liquid, and the spore suspension of mature Cladosporium tenuissimum was obtained by washing with deionized water. The Cladosporium tenuissimum used was isolated from the soil and was deposited in the General Microbiological Center of China Microbiological Strain Collection Administration (CGMCC) on March 4, 2022, with the deposit number of CGMCC No: 40141;

[0117] 2) Inoculate a suspension of Cladosporium tenuissima spores in a liquid culture medium to culture multifunctional mycelium balls, wherein the spore inoculation amount is 10 4spores / mL culture medium, wherein the liquid culture medium is composed of 15g / L anhydrous glucose, 1.5g / L NH4Cl, 0.9g / L KH2PO4, 0.7g / L MgSO4·7H2O and 30g / L NaCl, and deionized water is added to 1L, and then sterilized by high pressure, wherein the mycelial ball culture conditions are constant temperature culture at 28°C and 180rpm in a shaker for 168h. The mycelial balls formed are dark green spherical, with an average diameter of 1950μm, and an average sedimentation velocity of 1.0cm / s in 30g / L NaCl solution;

[0118] 3) inoculating Cladosporium microspheres and activated sludge in a wastewater treatment reactor, wherein the Cladosporium microspheres inoculation amount is 1 g / L, and the activated sludge inoculation amount is 3 g / L;

[0119] 4) The shale gas pressure return liquid (salinity of 3%, COD concentration of 850 mg / L) was treated by a sequencing batch reactor to cultivate aerobic granular sludge. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The simulated shale gas pressure return liquid was prepared by adding tap water to 1L, which contained 200 mg / L polyacrylamide, 220 mg / L isopropanol, 100 mg / L guar gum, 25 mg / L ethylene glycol, 40 mg / L n-hexadecane, 20 mg / L phenol, 30 mg / L aniline, 40 mg / L CaCl2, 37 mg / L MgSO4·7H2O, 37 mg / L FeSO4·7H2O and 30 g / L NaCl. The total time of each operation cycle in the batch operation is 6 hours. The pH of the reaction system is maintained at 7-8, the temperature is maintained at 20℃-25℃, the volume exchange rate of each cycle is 60%, the air enters from the bottom during the aeration stage, the superficial gas velocity is maintained at 1.2cm / s, and the static sedimentation time is 5min. The organic load of the reaction system is 2.04kgCOD / (m 3 ·sky).

[0120] According to experimental measurements, aerobic granular sludge was formed on the 17th day with an average particle size of 1190μm. The start-up period of aerobic granular sludge was 1-17 days, with an average organic matter removal rate of 36.5%, an average polyacrylamide removal rate of 9.2%, and an average isopropanol removal rate of 82.1%. From the 18th to the 29th day, the organic matter removal rate gradually increased to 70.2% and remained stable.

[0121] Example 3

[0122] Method for treating oil and gas field return fluid with multifunctional mycelium balls enhanced aerobic granular sludge:

[0123] 1) Inoculate the PDA slope with Aspergillus polydorum that has the ability to degrade organic matter in shale gas pressure return liquid, and wash with deionized water to obtain a spore suspension of mature Aspergillus polydorum;

[0124] 2) Inoculate a suspension of Aspergillus polyspores in a liquid culture medium to culture a multifunctional mycelium pellet, wherein the liquid culture medium is prepared by adding deionized water to 1 L, 20 g / L anhydrous glucose, 2 g / L NH4Cl, 1.2 g / L KH2PO4, 0.9 g / L MgSO4·7H2O and 50 g / L NaCl, and sterilizing by high pressure. The spore inoculation amount is 10 5 spores / mL culture medium, the mycelial pellet culture conditions are 30℃, 160rpm shaker constant temperature culture for 144h. The mycelial pellets formed are white spherical, with an average diameter of 1820μm, and an average sedimentation velocity of 1.35cm / s in 50g / LNaCl solution;

[0125] 3) Inoculating 1 g / L of Aspergillus polymorpha pellets and 3 g / L of activated sludge in a wastewater treatment reactor;

[0126] 4) The actual shale gas pressure return liquid (salinity of 5%, COD concentration of 800mg / L) was treated by cultivating aerobic granular sludge in a sequencing batch reactor. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The total time of each operation cycle during sequencing batch operation was 6h. The pH of the reaction system was maintained at 7-8, the temperature was maintained at 20℃-25℃, the volume exchange rate of each cycle was 50%, the air entered from the bottom during the aeration stage, the superficial gas velocity was maintained at 1.2cm / s, and the static sedimentation time was 5min. The organic load of the reaction system was 1.6kg COD / (m 3 ·sky).

[0127] Aerobic granular sludge was formed on the 13th day, with an average particle size of 1060μm. The start-up period of aerobic granular sludge was 1-13 days. The experimental results showed that the average organic matter removal rate was 42.1%, the average polyacrylamide removal rate was 13.9%, and the average isopropanol removal rate was 74.6%. From the 14th to the 23rd day, the organic matter removal rate gradually increased to 68.2% and remained stable.

[0128] Example 4

[0129] Method for treating oil and gas field return fluid with multifunctional mycelium balls enhanced aerobic granular sludge:

[0130] 1) Inoculating Cladosporium tenuissima with the ability to degrade organic matter in shale gas pressure return liquid on the PDA slant surface, and washing with deionized water to obtain a spore suspension of mature Cladosporium tenuissima;

[0131] 2) Inoculate a suspension of Cladosporium tenuissima spores in a liquid culture medium to culture multifunctional mycelium balls, wherein the spore inoculation amount is 10 6spores / mL culture medium, wherein the liquid culture medium is made of 10g / L anhydrous glucose, 1g / L NH4Cl, 0.7g / L KH2PO4, 0.5g / L MgSO4·7H2O and 100g / L NaCl, and deionized water is added to 1L, and then sterilized by high pressure, wherein the mycelial ball culture conditions are constant temperature culture at 30℃ and 160rpm in a shaker for 220h. The mycelial balls formed are dark green spherical, with an average diameter of 1320μm, and an average sedimentation velocity of 0.8cm / s in 100g / L NaCl solution;

[0132] 3) inoculating Cladosporium microspheres and activated sludge in a wastewater treatment reactor, wherein the inoculation amount of Cladosporium microspheres is 1 g / L, and the inoculation amount of activated sludge is 2 g / L;

[0133] 4) The shale gas pressure return liquid (salinity of 10%, COD concentration of 850 mg / L) was treated by culturing aerobic granular sludge in a sequencing batch reactor. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The simulated shale gas pressure return liquid was prepared by adding tap water to 1L, which contained 200 mg / L polyacrylamide, 220 mg / L isopropanol, 100 mg / L guar gum, 25 mg / L ethylene glycol, 40 mg / L n-hexadecane, 20 mg / L phenol, 30 mg / L aniline, 40 mg / L CaCl2, 37 mg / L MgSO4·7H2O, 37 mg / L FeSO4·7H2O and 100 g / L NaCl. The total time of each operation cycle in the batch operation is 6 hours. The pH of the reaction system is maintained at 7-8, the temperature is maintained at 20℃-25℃, the volume exchange rate of each cycle is 60%, the air enters from the bottom during the aeration stage, the superficial gas velocity is maintained at 1.2cm / s, and the static sedimentation time is 5min. The organic load of the reaction system is 2.04kgCOD / (m 3 ·sky).

[0134] The results of the experiment showed that aerobic granular sludge was formed on the 18th day, with an average particle size of 950μm. During the start-up period of aerobic granular sludge from 1 to 18 days, the average organic matter removal rate was 33.5%, the average polyacrylamide removal rate was 8.7%, and the average isopropanol removal rate was 74.4%. From the 19th to the 35th day, the organic matter removal rate gradually increased to 62.0% and remained stable.

[0135] Comparative Example 1

[0136] 1) inoculating activated sludge in a wastewater treatment reactor, wherein the activated sludge inoculation amount is 3 g / L;

[0137] 2) The simulated shale gas pressure return liquid (salinity of 3%, COD concentration of 850 mg / L) was treated by culturing aerobic granular sludge in a sequencing batch reactor. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The simulated shale gas pressure return liquid was prepared by adding tap water to 1L, which contained 200 mg / L polyacrylamide, 220 mg / L isopropanol, 100 mg / L guar gum, 25 mg / L ethylene glycol, 40 mg / L n-hexadecane, 20 mg / L phenol, 30 mg / L aniline, 40 mg / L CaCl2, 37 mg / L MgSO4·7H2O, 37 mg / L FeSO4·7H2O and 30 g / L NaCl. The total time of each operation cycle in the batch operation is 6 hours. The pH of the reaction system is maintained at 7-8, the temperature is maintained at 20℃-25℃, the volume exchange rate of each cycle is 60%, the air enters from the bottom during the aeration stage, the superficial gas velocity is maintained at 1.2cm / s, and the static sedimentation time is 5min. The organic load of the reaction system is 2.04kg COD / (m 3 ·sky);

[0138] 3) Aerobic granular sludge was formed on the 41st day, with an average particle size of 1050 μm. Figure 3 The aerobic granular sludge formed in Comparative Example 1 is shown. The average organic matter removal rate of the aerobic granular sludge during the startup period is 29.8%, the average polyacrylamide removal rate is 7.4%, and the average isopropanol removal rate is 59.9%.

[0139] Compared with Example 1 in general, Comparative Example 1 was not inoculated with Aspergillus polymorpha mycelial pellets.

[0140] Comparative Example 2

[0141] 1) inoculating activated sludge in a wastewater treatment reactor, wherein the activated sludge inoculation amount is 3 g / L;

[0142] 2) The sequencing batch reactor was used to cultivate aerobic granular sludge to treat shale gas pressure return liquid (salinity was 5%, COD concentration was 800mg / L). The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The total time of each operation cycle during the sequencing batch operation was 6h. The pH of the reaction system was maintained at 7-8, the temperature was maintained at 20℃-25℃, the volume exchange rate of each cycle was 50%, the air entered from the bottom during the aeration stage, the superficial gas velocity was maintained at 1.2cm / s, and the static sedimentation time was 5min. The organic load of the reaction system was 1.6kg COD / (m 3 ·sky);

[0143] 3) Aerobic granular sludge was not formed during the culture process. The average organic matter removal rate was 24.8% from 1 to 13 days and 33.2% from 14 to 30 days.

[0144] Compared with Example 3 in general, Comparative Example 2 was not inoculated with Aspergillus polymorpha mycelial pellets.

[0145] Comparative Example 3

[0146] 1) Inoculate Aspergillus niger (commonly available commercially) on a PDA slant, and wash with deionized water to obtain a spore suspension of mature Aspergillus niger;

[0147] 2) Inoculate a suspension of Aspergillus niger spores in a liquid culture medium to culture a multifunctional mycelium pellet, wherein the liquid culture medium is composed of 20 g / L anhydrous glucose, 2 g / L NH4Cl, 0.8 g / L KH2PO4, 0.9 g / L MgSO4·7H2O and 30 g / L NaCl, add deionized water to a volume of 1 L, and then sterilize by high pressure. The spore inoculation amount is 10 4 spores / mL culture medium, the mycelial pellet culture conditions are 28℃, 160rpm shaker constant temperature culture for 100h. The mycelial pellets formed are white spherical, with an average diameter of 1610μm, and an average sedimentation rate of 1.5cm / s in 30g / LNaCl solution;

[0148] 3) Inoculating 1 g / L of Aspergillus niger mycelium pellets and 3 g / L of activated sludge in a wastewater treatment reactor;

[0149] 4) The simulated shale gas pressure return liquid (salinity of 3%, COD concentration of 850 mg / L) was treated by culturing aerobic granular sludge in a sequencing batch reactor. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The simulated shale gas pressure return liquid was prepared by adding tap water to 1L, which contained 200 mg / L polyacrylamide, 220 mg / L isopropanol, 100 mg / L guar gum, 25 mg / L ethylene glycol, 40 mg / L n-hexadecane, 20 mg / L phenol, 30 mg / L aniline, 40 mg / L CaCl2, 37 mg / L MgSO4·7H2O, 37 mg / L FeSO4·7H2O and 30 g / L NaCl. The total time of each operation cycle in the batch operation is 6 hours. The pH of the reaction system is maintained at 7-8, the temperature is maintained at 20℃-25℃, the volume exchange rate of each cycle is 60%, the air enters from the bottom during the aeration stage, the superficial gas velocity is maintained at 1.2cm / s, and the static sedimentation time is 5min. The organic load of the reaction system is 2.04kg COD / (m 3 ·sky).

[0150] Compared with Example 1, the inoculation of Comparative Example 3 was Aspergillus niger mycelium pellets. Aerobic granular sludge was formed on the 28th day, and the average particle size of the aerobic granular sludge was 920 μm. The experimental results showed that the average organic matter removal rate of the aerobic granular sludge during the startup period was 30.2%, the average polyacrylamide removal rate was 9.4%, and the average isopropanol removal rate was 55.3%.

[0151] Comparative Example 4

[0152] 1) streaking Aspergillus tubingensis (commonly available commercially) on a PDA slant and washing with deionized water to obtain a spore suspension of mature Aspergillus tubingensis;

[0153] 2) Inoculate a suspension of Aspergillus tubingensis spores in a liquid culture medium to culture a multifunctional mycelium ball, wherein the spore inoculation amount is 10 5 spores / mL culture medium, wherein the liquid culture medium is made of 10g / L anhydrous glucose, 1g / L NH4Cl, 0.7g / L KH2PO4, 0.5g / L MgSO4·7H2O and 100g / L NaCl, and deionized water is added to 1L, and then sterilized by high pressure, wherein the mycelial ball culture conditions are constant temperature culture at 32℃ and 160rpm in a shaker for 200h. The mycelial balls formed are white, branch-like and irregular in shape, and the average sedimentation rate in 100g / L NaCl solution is 0.6cm / s;

[0154] 3) inoculating Aspergillus tubingensis mycelium pellets and activated sludge in a wastewater treatment reactor, wherein the inoculation amount of Aspergillus tubingensis mycelium pellets is 1 g / L, and the inoculation amount of activated sludge is 2 g / L;

[0155] 4) The shale gas pressure return liquid (salinity of 10%, COD concentration of 850 mg / L) was treated by culturing aerobic granular sludge in a sequencing batch reactor. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The simulated shale gas pressure return liquid was prepared by adding tap water to 1L, which contained 200 mg / L polyacrylamide, 220 mg / L isopropanol, 100 mg / L guar gum, 25 mg / L ethylene glycol, 40 mg / L n-hexadecane, 20 mg / L phenol, 30 mg / L aniline, 40 mg / L CaCl2, 37 mg / L MgSO4·7H2O, 37 mg / L FeSO4·7H2O and 100 g / L NaCl. The total time of each operation cycle in the batch operation is 6 hours. The pH of the reaction system is maintained at 7-8, the temperature is maintained at 20℃-25℃, the volume exchange rate of each cycle is 60%, the air enters from the bottom during the aeration stage, the superficial gas velocity is maintained at 1.2cm / s, and the static sedimentation time is 6min. The organic load of the reaction system is 2.04kgCOD / (m 3 ·sky).

[0156] Compared with Example 4, the inoculation of Aspergillus tubingensis pellets was used in Comparative Example 4. Aerobic granular sludge was not formed during the culture process under high salinity conditions, and the average organic matter removal rate was 23.3% from 1 to 18 days and 31.7% from 19 to 35 days.

[0157] Comparative Example 5

[0158] 1) streak inoculated with Penicillium citrinum (commonly available commercially) on a PDA slant, and wash with deionized water to obtain a spore suspension of mature Penicillium citrinum;

[0159] 2) Inoculate a liquid culture medium with a spore suspension of Penicillium citrinum to culture a multifunctional mycelium ball, wherein the spore inoculation amount is 10 6 spores / mL culture medium, wherein the liquid culture medium is made of 10g / L anhydrous glucose, 1g / L NH4Cl, 0.5g / L KH2PO4, 0.5g / L MgSO4·7H2O and 100g / L NaCl, and deionized water is added to 1L, and then sterilized by high pressure, wherein the mycelial ball culture condition is constant temperature culture at 28℃ and 140rpm in a shaker for 180h. No dense mycelial ball is formed;

[0160] 3) inoculating Penicillium citrinum mycelium pellets and activated sludge in a wastewater treatment reactor, wherein the inoculation amount of Penicillium citrinum mycelium pellets is 1 g / L and the inoculation amount of activated sludge is 2 g / L;

[0161] 4) The shale gas pressure return liquid (salinity of 10%, COD concentration of 850 mg / L) was treated by culturing aerobic granular sludge in a sequencing batch reactor. The operation process included water inlet, aeration, static sedimentation, water outlet and idle stage. The simulated shale gas pressure return liquid was prepared by adding tap water to 1L, which contained 200 mg / L polyacrylamide, 220 mg / L isopropanol, 100 mg / L guar gum, 25 mg / L ethylene glycol, 40 mg / L n-hexadecane, 20 mg / L phenol, 30 mg / L aniline, 40 mg / L CaCl2, 37 mg / L MgSO4·7H2O, 37 mg / L FeSO4·7H2O and 100 g / L NaCl. The total time of each operation cycle in the batch operation is 6 hours. The pH of the reaction system is maintained at 7-8, the temperature is maintained at 20℃-25℃, the volume exchange rate of each cycle is 60%, the air enters from the bottom during the aeration stage, the superficial gas velocity is maintained at 1.2cm / s, and the static sedimentation time is 5min. The organic load of the reaction system is 2.04kgCOD / (m 3 ·sky).

[0162] Compared with Example 4, the inoculation of the mycelial pellets of Penicillium citrinum was used in Comparative Example 5. Aerobic granular sludge was not formed during the culture process under high salinity conditions, and the average organic matter removal rate was 23.5% from 1 to 18 days and 30.9% from 19 to 35 days.

[0163] The above description is only a specific embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformation made by the present invention, or directly or indirectly applied in other related technical fields, is also included in the patent protection scope of the present invention.

[0164] For the specific conditions not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer were followed. For the reagents or instruments used without specifying the manufacturer, they were all conventional products that can be purchased commercially.

Claims

1. Multifunctional mycelium ball enhanced aerobic granular sludge, characterized in that: The multifunctional mycelium ball enhanced aerobic granular sludge is prepared by a method comprising the following steps: 1) Inoculate the fungal strain, culture it to maturity, and wash it to obtain a fungal spore suspension; 2) inoculating the fungal spore suspension into a culture medium to culture and obtain multifunctional mycelial balls; 3) inoculating the multifunctional mycelium pellets in a reactor; 4) introducing wastewater into the reactor, operating the reactor in a batch mode to treat the wastewater, and cultivating and obtaining the multifunctional mycelium ball-enhanced aerobic granular sludge; The fungus comprises at least one of Aspergillus polydorum and Cladosporium exigua, and the name of Aspergillus polydorum is Aspergillus polydorum NXY1 ( Aspergillus sydowii NXY1), with a deposit number of CGMCC No: 40215; the name of the Cladosporium exigua is Cladosporium exigua NXY8 ( Cladosporium tenuissimum NXY8), the deposit number is CGMCC No:40141.

2. The multifunctional mycelium ball enhanced aerobic granular sludge according to claim 1, characterized in that: The multifunctional mycelium ball enhanced aerobic granular sludge satisfies at least one of the following conditions a to q: a. The multifunctional mycelium ball has a spherical shape, an ellipsoidal shape, a rugby-shaped shape, a radial spherical shape, and an irregular spherical shape; b. the salinity tolerance of the fungus, calculated as sodium chloride, is 1 g / L to 100 g / L; c. the fungus has a salinity tolerance of 2 mS / cm to 170 mS / cm in terms of electrical conductivity; d. Step 2), wherein the culture medium is a liquid culture medium; e. In step 2), the culture medium contains 5 g / L to 80 g / L glucose, 0.5 g / L to 8 g / L NH4Cl, 0.3 g / L to 6 g / L KH2PO4, 0.25 g / L to 4 g / L MgSO4·7H2O, and 0 g / L to 80 g / L NaCl; f. In step 2), the culture medium contains 5 g / L to 80 g / L glucose, 0.5 g / L to 8 g / L NH4Cl, 0.3 g / L to 6 g / L KH2PO4, 0.25 g / L to 4 g / L MgSO4·7H2O, 0 g / L to 80 g / L NaCl, and water is added to make up to 1 L; g. Step 2), wherein the culture medium is sterilized by high pressure; h. In step 2), the inoculum size of fungal spores was 1×10 2 Up to 1×10 7 spores / mL medium; i. In step 2), the inoculum size of fungal spores is 1×10 2 Up to 1×10 7 spores / g medium; j. In step 2), the multifunctional mycelial ball is cultured at 15°C to 35°C; k. In step 2), the multifunctional mycelial ball is cultured at 60 rpm to 400 rpm; l. In step 2), the multifunctional mycelial ball is cultured at a constant temperature for 20 h to 240 h; m. In step 3), the inoculation amount of the multifunctional mycelium ball is 0.1 g / L to 10 g / L; n. In step 3), the multifunctional mycelial pellets and activated sludge are inoculated in a reactor; the mass ratio of the activated sludge to the multifunctional mycelial pellets is 0 to 90:1; o. In step 4), the batch operation process includes water inlet, aeration, static sedimentation, water outlet and idle stage; p. In step 4), the wastewater is oil and gas field pressure return fluid, the source of the oil and gas field pressure return fluid includes oil field pressure return fluid, natural gas field produced water, shale gas pressure return fluid, shale gas produced water, tight gas produced water; q. In step 4), the wastewater is oil and gas field pressure return fluid, and the oil and gas field pressure return fluid contains at least one of polyacrylamide, guar gum, isopropanol, ethylene glycol, hydrocarbons, heterocyclic compounds, phenol, aniline, petroleum and derivatives thereof; optionally, the hydrocarbons contain at least one of polycyclic aromatic hydrocarbons, alkylbenzenes, aliphatic hydrocarbons and derivatives thereof.

3. The multifunctional mycelium pellet-enhanced aerobic granular sludge according to any one of claims 1 to 2, characterized in that: In step 4), the batch operation satisfies at least one of the following conditions a to g: a. The total time of each operation cycle of batch operation is 1 h to 24 h; b. The pH of the reaction system is maintained at 5 to 9 during batch operation; c. The reaction temperature during batch operation is maintained at 15°C to 35°C; d. The volume exchange rate per cycle during batch operation is maintained at 30% to 80%; e. During the aeration phase of sequencing batch operation, air enters from the bottom, the superficial air velocity is maintained at 0.1 cm / s to 4.5 cm / s, and the dissolved oxygen concentration is controlled at 2 mg / L to 10 mg / L; f. The time range of the static settling phase in batch operation is 0.1 min to 30 min; g. The organic load range of the reaction system during batch operation is 0.3 kg COD / (m 3 ·day) to 25 kg COD / (m 3 ·sky).

4. A method for treating oil and gas field pressure return fluid by using multifunctional mycelial pellets to strengthen aerobic granular sludge, characterized in that: The method comprises the following steps: 1) Inoculate the fungal strain, culture it to maturity, and wash it to obtain a fungal spore suspension; 2) inoculating the fungal spore suspension into a culture medium to culture and obtain multifunctional mycelial balls; 3) inoculating the multifunctional mycelium pellets in a reactor; 4) introducing wastewater into the reactor, operating the reactor in a batch mode to treat the wastewater, cultivating and obtaining multifunctional mycelial pellet-enhanced aerobic granular sludge, wherein the wastewater is oil and gas field pressure return fluid; The fungus comprises at least one of Aspergillus polydorum and Cladosporium exigua, and the name of Aspergillus polydorum is Aspergillus polydorum NXY1 ( Aspergillus sydowii NXY1), with a deposit number of CGMCC No: 40215; the name of the Cladosporium exigua is Cladosporium exigua NXY8 ( Cladosporium tenuissimum NXY8), the deposit number is CGMCC No: 40141.

5. The method according to claim 4, characterized in that The multifunctional mycelium ball enhanced aerobic granular sludge satisfies at least one of the following conditions a to o: a. The multifunctional mycelium ball has a spherical shape, an ellipsoidal shape, a rugby ball shape, a radial spherical shape, and an irregular spherical shape; b. the salinity tolerance of the fungus, calculated as sodium chloride, is 1 g / L to 100 g / L; c. the fungus has a salinity tolerance of 2 mS / cm to 170 mS / cm in terms of electrical conductivity; d. Step 2), wherein the culture medium is a liquid culture medium; e. In step 2), the culture medium contains 5 g / L to 80 g / L glucose, 0.5 g / L to 8 g / L NH4Cl, 0.3 g / L to 6 g / L KH2PO4, 0.25 g / L to 4 g / L MgSO4·7H2O, and 0 g / L to 80 g / L NaCl; f. In step 2), the culture medium contains 5 g / L to 80 g / L glucose, 0.5 g / L to 8 g / L NH4Cl, 0.3 g / L to 6 g / L KH2PO4, 0.25 g / L to 4 g / L MgSO4·7H2O, 0 g / L to 80 g / L NaCl, and water is added to make up to 1 L; g. Step 2), wherein the culture medium is sterilized by high pressure; h. In step 2), the inoculum size of fungal spores is 1×10 2 Up to 1×10 7 spores / mL medium; i. In step 2), the inoculum size of fungal spores is 1×10 2 Up to 1×10 7 spores / g medium; j. In step 2), the multifunctional mycelial ball is cultured at 15°C to 35°C; k. In step 2), the multifunctional mycelial ball is cultured at 60 rpm to 400 rpm; l. In step 2), the multifunctional mycelial ball is cultured at a constant temperature for 20 h to 240 h; m. In step 3), the inoculation amount of the multifunctional mycelium ball is 0.1 g / L to 10 g / L; n. In step 3), the multifunctional mycelial pellets and activated sludge are inoculated in a reactor; the mass ratio of the activated sludge to the multifunctional mycelial pellets is 0 to 90:1; o. In step 4), the sequencing batch operation process includes water inlet, aeration, static sedimentation, water outlet and idle stages.

6. The method according to claim 4, characterized in that In step 4), the batch operation satisfies at least one of the following conditions a to g: a. The total time of each operation cycle of batch operation is 1 h to 24 h; b. The pH of the reaction system is maintained at 5 to 9 during batch operation; c. The reaction temperature during batch operation is maintained at 15°C to 35°C; d. The volume exchange rate per cycle during batch operation is maintained at 30% to 80%; e. During the aeration phase of sequencing batch operation, air enters from the bottom, the superficial air velocity is maintained at 0.1 cm / s to 4.5 cm / s, and the dissolved oxygen concentration is controlled at 2 mg / L to 10 mg / L; f. The time range of the static settling phase in batch operation is 0.1 min to 30 min; g. The organic load range of the reaction system during batch operation is 0.3 kg COD / (m 3 ·day) to 25 kg COD / (m 3 ·sky).

7. The method according to claim 4, characterized in that In step 4), the source of the oil and gas field pressure return fluid includes at least one of oil field pressure return fluid, natural gas field produced water, shale gas pressure return fluid, shale gas produced water, and tight gas produced water.

8. The method according to any one of claims 4 to 7, characterized in that: In step 4), the oil and gas field pressure return fluid contains at least one of polyacrylamide, guar gum, isopropanol, ethylene glycol, hydrocarbons, heterocyclic compounds, phenol, aniline, petroleum and their derivatives; optionally, the hydrocarbons contain at least one of polycyclic aromatic hydrocarbons, alkylbenzenes, aliphatic hydrocarbons and their derivatives.

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