Sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system

Abstract

The utility model provides a sodium percarbonate oxidation reinforced low-pressure membrane method shale gas wastewater treatment system, and relates to the technical field of wastewater treatment. The sodium percarbonate oxidation reinforced low-pressure membrane method shale gas wastewater treatment system comprises a contact oxidation reaction tank, a low-pressure membrane unit and a water production unit, wherein the contact oxidation reaction tank is provided with a sodium percarbonate oxidizing agent adding pipeline and supply equipment for providing an activating agent for activating a sodium percarbonate oxidizing agent; the low-pressure membrane unit comprises a low-pressure membrane reaction tank and a membrane assembly arranged in the low-pressure membrane reaction tank, a water outlet of the contact oxidation reaction tank is communicated with a water inlet of the low-pressure membrane reaction tank, and the low-pressure membrane reaction tank is connected with a water outlet pipeline; the produced water unit comprises a produced water overflow pool and a produced water collecting pool, a water inlet of the produced water overflow pool is communicated with the water outlet pipeline, and a water outlet of the produced water overflow pool is communicated with the produced water collecting pool. The system can reduce membrane pollution in the process of purifying the shale gas wastewater by the low-pressure membrane and improve the wastewater treatment effect.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and in particular to a sodium percarbonate oxidation-enhanced low-pressure membrane shale gas wastewater treatment system. Background Art

[0002] Shale gas is a new type of energy gas rich in methane. As a type of unconventional natural gas, it has been widely used in various fields such as chemical industry and power supply. The greenhouse gas emissions generated by shale gas mining are 50% lower than those of coal mining, significantly reducing carbon emissions and air pollution. It is a greener and more environmentally friendly clean energy that is expected to replace traditional fossil energy. Currently, the total global shale gas resources have reached 4.56×10 14 m 3 , while my country's total shale gas resources are estimated to be 1×10 14 m 3 At the same time, with the continuous development and maturity of mining technologies such as horizontal drilling and hydraulic fracturing, global shale gas mining has shown a booming development momentum.

[0003] However, during drilling and hydraulic fracturing, large amounts of water are injected into the ground for extraction. After extraction is complete, some of this water returns to the surface as flowback fluid and produced water. This water is collectively referred to as shale gas wastewater. Due to the addition of chemicals such as friction reducers, surfactants, corrosion inhibitors, and flow improvers during the fracturing process, the wastewater that returns to the surface is complex, containing large amounts of suspended solids, cations, anions, organic matter, and naturally occurring radioactive substances. If this wastewater is not treated, it will not only be unable to be recycled internally, but if discharged, it will seriously pollute the local water environment and disrupt the ecological balance. Therefore, there is an urgent need for an effective and feasible technology to treat this wastewater.

[0004] Low-pressure membrane technologies, including microfiltration and ultrafiltration, intercept pollutants through membrane pore size, can remove particulate matter and some organic compounds, and are extremely effective technologies for treating shale gas wastewater. However, membrane fouling problems caused by shale gas wastewater treatment have limited the large-scale application of low-pressure membranes in wastewater treatment. Membrane fouling can be affected by various factors, such as the properties of the membrane and the characteristics of the influent. In addition to the properties of the membrane itself, the characteristics of the influent also have a significant impact on the fouling of low-pressure membranes. Water quality parameters such as total dissolved solids (TDS), turbidity, organic matter, and total organic carbon (TOC) can all cause fouling of low-pressure membranes. Utility Model Content

[0005] The present application provides a sodium percarbonate oxidation-enhanced low-pressure membrane shale gas wastewater treatment system, which can reduce membrane pollution during the low-pressure membrane purification of shale gas wastewater and improve the wastewater treatment effect.

[0006] This application is implemented as follows:

[0007] This application provides a sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system, including:

[0008] An aerobic contact reactor, which is provided with a sodium percarbonate oxidant dosing pipeline and a feeding device for an activator for providing an activated sodium percarbonate oxidant;

[0009] A low-pressure membrane unit, which includes a low-pressure membrane reaction tank and a membrane module arranged in the low-pressure membrane reaction tank. The water outlet of the aerobic contact reactor is communicated with the water inlet of the low-pressure membrane reaction tank, and the low-pressure membrane reaction tank is connected with a water outlet pipeline; and

[0010] A water production unit, which includes a water production overflow tank and a water production collection tank. The water inlet of the water production overflow tank is communicated with the water outlet pipeline, and the water outlet of the water production overflow tank is communicated with the water production collection tank.

[0011] In a possible implementation scheme, it further includes a vacuum pump, which is communicated with the water outlet pipeline through a vacuum pipeline, and the vacuum pipeline is provided with a vacuum valve.

[0012] In a possible implementation scheme, a water production valve and a flow sensor are arranged on the water outlet pipeline.

[0013] In a possible implementation scheme, the water production overflow tank and the water production collection tank are integrally arranged and separated by an overflow plate. The overflow plate is provided with overflow holes, and the overflow plate communicates the water production overflow tank and the water production collection tank.

[0014] In a possible implementation scheme, a drain port is arranged at the bottom of the low-pressure membrane reaction tank. The drain port is connected with a drain pipeline, and the drain pipeline is provided with a drain valve.

[0015] In a possible implementation scheme, the water outlet of the aerobic contact reactor is communicated with the water inlet of the low-pressure membrane reaction tank through a first pipeline, and the first pipeline is provided with a first water inlet valve.

[0016] In a possible implementation scheme, a stirring device is further arranged in the aerobic contact reactor.

[0017] In a possible implementation scheme, an ultraviolet light source is further arranged above the aerobic contact reactor to provide ultraviolet light for activating the sodium percarbonate oxidant, or the sodium percarbonate reaction tank is provided with an Fe(II) activator dosing pipeline to provide an Fe(II) activator for activating the sodium percarbonate oxidant.

[0018] In a possible implementation, it further includes a high-level water tank and a constant-level water tank. The water outlet of the high-level water tank is communicated with the water inlet of the constant-level water tank, and the water outlet of the constant-level water tank is communicated with the water inlet of the contact oxidation reaction tank; the shale gas wastewater is pumped to the high-level water tank by a lift pump.

[0019] In a possible implementation, a water level sensor is provided in the constant-level water tank.

[0020] The embodiments of the present application at least have the following beneficial effects:

[0021] In the sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system of the present application, a sodium percarbonate oxidant and an activator for providing an activated sodium percarbonate oxidant are fed into the contact oxidation reaction tank through a sodium percarbonate oxidant feeding pipeline and a feeding device for the activator. The oxidation of activated sodium percarbonate is used as a pre-treatment process for the low-pressure membrane unit to treat special water bodies such as shale gas wastewater, effectively removing aromatic organic compounds and soluble microbial by-products in the wastewater, ensuring the water quality of the influent for subsequent low-pressure membrane filtration, greatly restoring the terminal flux of low-pressure membrane filtration, effectively controlling the membrane fouling problem of low-pressure membrane treatment of shale gas wastewater, and being beneficial to improving the wastewater treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic diagram of the sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system in the specific implementation manner of the present application.

[0024] Reference numerals: 10 - Sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system; 11 - Contact oxidation reaction tank; 111 - Sodium percarbonate oxidant feeding pipeline; 112 - Fe activator feeding pipeline; 113 - Stirring device; 114 - First inlet valve; 12 - Low-pressure membrane unit; 121 - Low-pressure membrane reaction tank; 122 - Membrane module; 123 - Outlet pipeline; 124 - Product water valve; 125 - Flow sensor; 126 - Venting pipeline; 127 - Venting valve; 13 - Product water unit; 131 - Product water overflow tank; 132 - Product water collection tank; 133 - Overflow plate; 141 - Vacuum pump; 142 - Vacuum pipeline; 143 - Vacuum valve; 151 - High-level water tank; 152 - Constant-level water tank; 153 - Water level sensor; 154 - Lift pump; 155 - Second inlet valve. Detailed implementation manners

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0027] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of this application is normally placed, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application. In addition, terms such as "first", "second", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present application, it should also be noted that unless otherwise clearly specified and limited, the terms "arranged", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations. Embodiment

[0029] This embodiment provides a sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system 10, which includes a contact oxidation reaction tank 11, a low-pressure membrane unit 12 and a water production unit 13.

[0030] Among them, the contact oxidation reaction tank 11 is provided with a sodium percarbonate oxidant dosing pipeline 111 and an Fe activator dosing pipeline 112. Through the sodium percarbonate oxidant dosing pipeline 111, a feeding device for providing an activator for activating the sodium percarbonate oxidant is used to add the sodium percarbonate oxidant and the activator for activating the sodium percarbonate oxidant to the contact oxidation reaction tank 11. The activated sodium percarbonate oxidation is adopted as a pre-treatment process for the low-pressure membrane unit 12 to treat special water bodies such as shale gas wastewater. The sodium percarbonate oxidant effectively removes aromatic organic compounds and soluble microbial by-products in the wastewater.

[0031] Among them, the sodium percarbonate reaction tank is provided with an Fe(II) activator dosing pipeline 112 to provide an Fe(II) activator for activating the sodium percarbonate oxidant.

[0032] The Fe(II) activator can activate the sodium percarbonate oxidant. Moreover, Fe(II) can oxidize H2O2 to generate hydroxyl radicals, and mineralize the organic matter by depriving the electrons of the organic matter. At the same time, the Fe(III) formed by the oxidation of Fe(II) produces a coagulation effect, which can remove a large amount of colloids and part of the organic matter.

[0033] Optionally, the concentration of sodium percarbonate is 1-15 mmol / L, and the concentration ratio of the Fe(II) activator to sodium percarbonate is 1:1. Among them, the sodium percarbonate is in the form of granular powder, which is easier to transport and store, and the sodium percarbonate can also be used in a wider pH range.

[0034] In other embodiments, an ultraviolet light source can also be provided above the contact oxidation reaction tank 11. The ultraviolet light source can emit ultraviolet light, and the ultraviolet light can also activate the sodium percarbonate, thereby effectively removing aromatic organic compounds and soluble microbial by-products in the wastewater. Exemplarily, the UV lamp power of the ultraviolet light source is 5-100 W, the irradiation time is 5-120 min, and the immersion depth is 0-10 cm.

[0035] Exemplarily, a stirring device 113 is further provided in the contact oxidation reaction tank 11. Through the stirring device 113, the added sodium percarbonate oxidant and Fe(II) activator can be mixed more evenly.

[0036] The low-pressure membrane unit 12 includes a low-pressure membrane reaction tank 121 and a membrane module 122 provided in the low-pressure membrane reaction tank 121. The water outlet of the contact oxidation reaction tank 11 is communicated with the water inlet of the low-pressure membrane reaction tank 121, and the low-pressure membrane reaction tank 121 is connected with a water outlet pipeline 123. Among them, the filtration driving mode of the low-pressure membrane unit 12 can be any one of conventional suction filtration, gravity driving, and pressure pump circulation driving.

[0037] Among them, the water outlet of the biological contact oxidation reaction tank 11 is communicated with the water inlet of the low-pressure membrane reaction tank 121 through a first pipeline, and a first water inlet valve 114 is provided on the first pipeline. The water in the biological contact oxidation reaction tank 11 can be controlled to enter the low-pressure membrane reaction tank 121 through the first water inlet valve 114.

[0038] Among them, the membrane module 122 uses a microfiltration membrane or an ultrafiltration membrane, and the membrane pore size is 0.01 - 0.45 μm. Exemplarily, when an ultrafiltration membrane is selected, the filtration head of the ultrafiltration membrane module 122 is 0.4 - 1.2 m, the backwash flux is 15 - 150 L / (m 2 ·h), and the backwash duration is 30 - 180 s. During the backwash process, the aeration intensity (calculated based on the bottom area of the membrane tank) is 60 - 180m 3 / (m 2 ·h), and the aeration time is 15 - 120 s. When a microfiltration membrane is used, the filtration pressure of the nanofiltration membrane in the membrane module 122 is 50 - 200 kPa, the filtration cycle is 6 - 24 h, and the cross-flow velocity is 0.1 - 0.5 m / s.

[0039] Optionally, the form of the membrane module 122 is a hollow fiber membrane or a flat membrane. Optionally, the material of the membrane module 122 is an organic membrane or an inorganic membrane; when an organic membrane is used, it is polyethersulfone (PES), polysulfone (PS), polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polypropylene (PP), polyacrylonitrile (PAN) or cellulose acetate (CA); when an inorganic membrane is used, it is alumina (Al2O3), zirconia (ZrO2), titanium dioxide (TiO2) or silica (SiO2).

[0040] The water production unit 13 includes a water production overflow tank 131 and a water production collection tank 132. The water inlet of the water production overflow tank 131 is communicated with the water outlet pipeline 123, and the water outlet of the water production overflow tank 131 is communicated with the water production collection tank 132. Among them, a water production valve 124 and a flow sensor 125 are provided on the water outlet pipeline 123, and the water treated in the low-pressure membrane reaction tank 121 can be controlled to enter the water production overflow tank 131 through the water production valve 124. In addition, a vacuum pump 141 is provided, and the vacuum pump 141 is communicated with the water outlet pipeline 123 through a vacuum pipeline 142, and a vacuum valve 143 is provided on the vacuum pipeline 142.

[0041] Optionally, a drain port is provided at the bottom of the low-pressure membrane reaction tank 121, and the drain port is connected to a drain pipeline 126, and a drain valve 127 is provided on the drain pipeline 126. The liquid in the low-pressure membrane reaction tank 121 can be controlled to be drained through the drain valve 127 and flow out from the drain pipeline 126.

[0042] Exemplarily, the produced water overflow pool 131 and the produced water collection pool 132 are integrally arranged and separated by an overflow plate 133. The overflow plate 133 is provided with overflow holes and connects the produced water overflow pool 131 and the produced water collection pool 132.

[0043] Furthermore, the sodium percarbonate oxidation enhanced low-pressure membrane shale gas wastewater treatment system 10 further includes a high-level water tank 151 and a constant-level water tank 152. The water outlet of the high-level water tank 151 is connected to the water inlet of the constant-level water tank 152, and the water outlet of the constant-level water tank 152 is connected to the water inlet of the contact oxidation reaction tank 11; the shale gas wastewater is pumped to the high-level water tank 151 by a lift pump 154. Among them, the lift pump 154 and the high-level water tank 151 are connected by a second pipeline, and the second pipeline is provided with a second inlet valve 155. In addition, a water level sensor 153 is provided in the constant-level water tank 152, and the liquid level of the constant-level water tank 152 is kept constant through the feedback adjustment of the water level sensor 153.

[0044] The working principle of the sodium percarbonate oxidation enhanced low-pressure membrane shale gas wastewater treatment system 10 of the present application is as follows:

[0045] The shale gas wastewater first enters the high-level water tank 151 through the lift pump 154 and the second inlet valve 155, and then flows into the constant-level water tank 152. The water in the constant-level water tank 152 is kept at a constant liquid level through the feedback adjustment of the water level sensor 153. The water in the constant-level water tank 152 enters the contact oxidation reaction tank 11 for sodium percarbonate activation oxidation pretreatment; the effluent of the contact oxidation reaction tank 11 enters the low-pressure membrane unit 12. When the filtration starts, the vacuum pump 141 and the vacuum valve 143 are first turned on to fill the water outlet pipeline 123 with water, and then the vacuum pump and the vacuum valve 143 are closed. The filtered water enters the support layer through the active layer of the membrane module 122 to be purified. The produced water of the low-pressure membrane unit 12 enters the produced water overflow pool 131. The permeation flux of the membrane module 122 is obtained by calculating through the flow sensor 125 on the water outlet pipeline 123 and the membrane area; the water outlet pipeline 123 of the low-pressure membrane unit 12 is immersed under the liquid level of the produced water overflow pool 131, and then enters the produced water collection pool 132 through the overflow holes of the overflow plate 133, and finally enters the subsequent advanced treatment process. The excess liquid in the low-pressure membrane reaction tank 121 can be discharged through the emptying pipeline 126.

[0046] The sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system 10 of the present application uses the sodium percarbonate oxidant dosing pipeline 111 to add sodium percarbonate oxidant and the activator for activating the sodium percarbonate oxidant to the contact oxidation reaction tank 11 through the feeding device for the activator that provides the activator for activating the sodium percarbonate oxidant. The activated sodium percarbonate oxidation is used as the pre-treatment process of the low-pressure membrane unit 12 to treat special water bodies such as shale gas wastewater, effectively removing aromatic organic matters and soluble microbial by-products in the wastewater, ensuring the influent water quality of the subsequent low-pressure membrane filtration, greatly restoring the end flux of the low-pressure membrane filtration, effectively controlling the membrane pollution problem of the low-pressure membrane for treating shale gas wastewater, and being beneficial to improving the wastewater treatment effect. At the same time, it makes full use of the complementary and synergistic effects of Fe(III) coagulation, sodium percarbonate oxidation, and low-pressure membrane filtration in purifying the water quality of shale gas wastewater, and greatly controls the membrane pollution trend of the low-pressure membrane. Moreover, the sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system 10 of the present application has the characteristics of modularization and can be made into a mobile purification unit, which is convenient for installation and transportation. At the same time, it has the advantages of low operating cost, easy maintenance, no need for power and chemical agents, and is especially suitable for the actual operation of shale gas wastewater at the mining site. And the flux change trend of the low-pressure membrane filtration adopted is similar to the return drainage volume change trend of shale gas wastewater, which is especially suitable for the actual operation of shale gas wastewater at the mining site. Example

[0047] In this example, the wastewater from a shale gas well in the Sichuan Basin was used as the raw water, with a turbidity of 113 NTU, UV254 of 0.186 cm -1 , DOC of 34.5 mg / L, TDS of 15800 mg / L, pH of 3.08, and conductivity of 30.1 mS / cm. The membrane module used a PVDF ultrafiltration membrane for the filtration experiment, with a pore size of 0.20 μm and an effective filtration area of 0.00418 m 2 , and it was soaked in deionized water for 48 h before use. The stirring device ZR4-6 coagulation test mixer in the contact oxidation reaction tank was used for oxidation stirring during pre-treatment. Sodium percarbonate was activated by using Fe(II) activator or ultraviolet lamp respectively, and the power of the ultraviolet lamp was 10 W. The nitrogen cylinder was used to provide a constant filtration pressure (50 kPa) for the low-pressure membrane module unit.

[0048] The test results are as follows:

[0049] 1. The optimal light condition for UV activation is a submerged depth of 6 cm. First, the stirring device 113 operates at a rate of 500 r / min for 1 min, and then at 200 r / min for 59 min. At this time, the terminal flux recovers from 724 LMH to 628 LMH. Sodium percarbonate at 10 mmol / L has the best pretreatment effect under two activation methods, namely activation with Fe(II) activator and UV lamp. During UV activation, the terminal flux recovers from 17 LMH to 740 LMH. Due to the coagulation effect of Fe(III) generated by the oxidation during Fe(II) activation, the pretreatment effect on shale gas wastewater is better, and the terminal flux recovers to 1553 LMH.

[0050] 2. Pretreatment with sodium percarbonate under both UV and Fe(II) activation methods effectively removes aromatic organic compounds and soluble microbial byproduct organic compounds in the wastewater. After grading UV254, it is found that pretreatment with sodium percarbonate under both activation methods can effectively remove the hydrophobic part of UV254. During UV activation, the proportion of the hydrophobic part decreases from 40.3% to 26.6%, while during Fe(II) activation, it decreases to 28.4%.

[0051] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. An enhanced low-pressure membrane method for treating shale gas wastewater by sodium percarbonate oxidation, characterized in that Comprising: An activated oxidation reaction tank, which is provided with a sodium percarbonate oxidant dosing pipeline and a feeding device for an activator for providing an activated sodium percarbonate oxidant; A low-pressure membrane unit, which includes a low-pressure membrane reaction tank and a membrane module disposed in the low-pressure membrane reaction tank. The water outlet of the activated oxidation reaction tank is communicated with the water inlet of the low-pressure membrane reaction tank, and the low-pressure membrane reaction tank is connected with a water outlet pipeline; and A water production unit, which includes a water production overflow tank and a water production collection tank. The water inlet of the water production overflow tank is communicated with the water outlet pipeline, and the water outlet of the water production overflow tank is communicated with the water production collection tank.

2. The sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system according to claim 1, wherein It further includes a vacuum pump, which is communicated with the water outlet pipeline through a vacuum pipeline, and the vacuum pipeline is provided with a vacuum valve.

3. The sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system according to claim 1, characterized in that A water production valve and a flow sensor are provided on the water outlet pipeline.

4. The sodium percarbonate oxidation enhanced low-pressure membrane shale gas wastewater treatment system according to any one of claims 1 to 3, wherein The water production overflow tank and the water production collection tank are integrally arranged and separated by an overflow plate. The overflow plate is provided with overflow holes, and the overflow plate communicates the water production overflow tank and the water production collection tank.

5. The sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system according to any one of claims 1 to 3, characterized in that, A drain opening is provided at the bottom of the low-pressure membrane reaction tank, and the drain opening is connected with a drain pipeline, and the drain pipeline is provided with a drain valve.

6. The sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system according to any one of claims 1 to 3, characterized in that, The water outlet of the activated oxidation reaction tank is communicated with the water inlet of the low-pressure membrane reaction tank through a first pipeline, and the first pipeline is provided with a first water inlet valve.

7. The sodium percarbonate oxidation enhanced low-pressure membrane shale gas wastewater treatment system according to any one of claims 1 to 3, characterized in that, A stirring device is further arranged in the activated oxidation reaction tank.

8. The sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system according to any one of claims 1 to 3, characterized in that, An ultraviolet light source is further provided above the activated oxidation reaction tank to provide ultraviolet light for activating the sodium percarbonate oxidant, or the sodium percarbonate reaction tank is provided with an Fe(II) activator dosing pipeline to provide an Fe(II) activator for activating the sodium percarbonate oxidant.

9. The sodium percarbonate oxidation enhanced low-pressure membrane method shale gas wastewater treatment system according to any one of claims 1 to 3, characterized in that, It further includes a high-level water tank and a constant-level water tank. The water outlet of the high-level water tank is communicated with the water inlet of the constant-level water tank, and the water outlet of the constant-level water tank is communicated with the water inlet of the activated oxidation reaction tank; the shale gas wastewater is pumped to the high-level water tank by a lift pump.

10. The sodium percarbonate oxidation enhanced low-pressure membrane shale gas wastewater treatment system according to claim 9, wherein A water level sensor is arranged in the constant-level water tank.

Images