A device and method for treating heavy oil wastewater

Abstract

The application relates to a thickened oil sewage treatment device, which comprises a sewage treatment tank, sludge comprising a heavy carrier, which is arranged at the bottom of one side of the sewage treatment tank, an aeration device arranged above the sludge, a plug flow device arranged at the bottom of the sewage treatment tank, a sewage inlet arranged at one side of the sewage treatment tank and above the aeration device, and a sewage outlet arranged at the other side of the sewage treatment tank and above the aeration device. The thickened oil sewage treatment device and method provided by the application can form sludge by using a heavy carrier, make the sludge deposit at the bottom of the sewage treatment tank, separate the sludge and the sewage by the aeration device, make the dissolved oxygen content in the sludge lower and the dissolved oxygen content in the sewage higher, make the sewage treatment tank simultaneously carry out aerobic biochemical reaction and anaerobic biochemical reaction, and realize effective treatment of the thickened oil sewage.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental protection, in particular to sewage treatment. BACKGROUND

[0002] Oilfield heavy oil sewage is the product of the water system after oil-water separation of the gathering system, and belongs to the series of heavy oil production sewage and associated water mixture. In the process of heavy oil production, the development methods are diverse and basically accompanied by high temperature environment, resulting in that the heavy oil sewage contains a large amount of organic matter and a large amount of inorganic metal ion compounds of solite. Due to the characteristics of heavy crude oil, most of the organic matter in the heavy oil sewage is wax, asphaltene, colloid and other impurities. The collection and separation characteristics of heavy oil sewage are widely existed, which are macroscopically manifested as high emulsification degree, high mineralization degree, high salinity and high ionic degree. Due to the complexity of geology and stratum, the heavy oil sewage system is poor and has low stability, so it is extremely difficult to achieve compliance discharge of the heavy oil sewage. SUMMARY

[0003] The embodiments of the present application provide a heavy oil sewage treatment device and method to solve the technical problem of difficult heavy oil sewage treatment.

[0004] In a first aspect, the embodiments of the present application provide a heavy oil sewage treatment device, which comprises:

[0005] a sewage treatment tank;

[0006] sludge comprising a heavy carrier, arranged at the bottom of one side of the sewage treatment tank;

[0007] an aeration device arranged above the sludge;

[0008] a plug flow device arranged at the bottom of the sewage treatment tank;

[0009] a sewage inlet arranged at one side of the sewage treatment tank and above the aeration device;

[0010] a sewage outlet arranged at the other side of the sewage treatment tank and above the aeration device.

[0011] In some embodiments of the present application, the heavy oil sewage treatment device further comprises a primary secondary sedimentation tank, and the sewage outlet is in communication with the primary secondary sedimentation tank.

[0012] In some embodiments of the present application, the heavy oil sewage treatment device further comprises a secondary aerobic tank and a secondary secondary sedimentation tank in communication, the primary secondary sedimentation tank is in communication with the secondary aerobic tank, and the secondary secondary sedimentation tank is in communication with the sewage inlet.

[0013] In some embodiments of the present application, the thickened oil sewage treatment device further comprises a sludge circulation pipe, which is arranged at the bottom of one side of the sewage treatment tank, and the primary secondary sedimentation tank is connected to the sludge circulation pipe.

[0014] In a second aspect, the embodiments of the present application provide a thickened oil sewage treatment method, which is realized by the thickened oil sewage treatment device of the first aspect, and comprises the following steps:

[0015] introducing sewage from the sewage inlet into the sewage treatment tank, and adding heavy carriers into the sewage treatment tank, so that the heavy carriers form sludge;

[0016] operating the aeration device to increase the oxygen content of the sewage above the aeration device, so that the sewage above the aeration device performs aerobic biochemical reaction;

[0017] making the sludge below the air permeation device perform anaerobic biochemical reaction;

[0018] pushing the sludge at the bottom of the sewage treatment tank to the upper part of the sewage treatment tank by the plug flow device, mixing with the sewage after aerobic biochemical reaction to form primary treated sewage, and discharging the primary treated sewage through the sewage outlet.

[0019] In some embodiments of the present application, after the primary treated sewage enters the primary secondary sedimentation tank through the sewage outlet, the primary treated sewage enters the secondary aerobic tank to perform aerobic biochemical reaction, then enters the secondary secondary sedimentation tank, and is circulated back to the sewage treatment tank through the sewage inlet.

[0020] In some embodiments of the present application, after the primary treated sewage enters the primary secondary sedimentation tank through the sewage outlet, the primary treated sewage is circulated back to the sewage treatment tank through the sludge circulation pipe.

[0021] In some embodiments of the present application, when the sewage is treated in the sewage treatment tank,

[0022] the hydraulic retention time is 13-15 h; and / or,

[0023] the COD load is 10.8-16.8 kg / (m 3 ·d); and / or,

[0024] the liquid phase pH value is 7.0-7.5; and / or,

[0025] the water temperature is 25-30℃; and / or,

[0026] the suspended sludge concentration is 11000-13000 mg / L.

[0027] In some embodiments of the present application, the dissolved oxygen concentration of the sewage above the aeration device is 6-8 mg / L; and / or,

[0028] The dissolved oxygen concentration in the anaerobic environment below the aeration device is less than 0.2 mg / L.

[0029] In some embodiments of the present application, the reflux ratio of the high dissolved oxygen environment in the sewage treatment tank is 120%-135%; and / or,

[0030] The reflux ratio of the anaerobic internal circulation is 85%-100%.

[0031] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0032] The thick oil sewage treatment device and method provided by the embodiments of the present application form sludge by using heavy carriers, so that the sludge is deposited at the bottom of the sewage treatment tank. The sludge and the sewage are separated by the aeration device, so that the dissolved oxygen content in the sludge is relatively low, and the dissolved oxygen content in the sewage is relatively high. This makes the sewage treatment tank can simultaneously carry out aerobic biochemical reaction and anaerobic biochemical reaction, and realizes effective treatment of thick oil sewage. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the present application.

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0035] Figure 1 The structural schematic diagram of the sewage treatment tank provided by the embodiments of the present application is shown in the figure.

[0036] Figure 2 The dissolved oxygen content distribution schematic diagram in the sewage treatment tank provided by the embodiments of the present application is shown in the figure.

[0037] Figure 3 The structural schematic diagram of a thick oil sewage treatment device provided by the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0039] Unless otherwise specifically indicated, the terms used herein are understood to have the meanings as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. If there is a contradiction, the specification takes precedence.

[0040] Unless otherwise specifically indicated, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0041] The existing thickened oil sewage treatment has a difficult technical problem.

[0042] The technical solutions provided by the embodiments of the present application are to solve the above technical problems, and the general idea is as follows:

[0043] In a first aspect, the embodiments of the present application provide a thickened oil sewage treatment device, please refer to Figure 1 、 Figure 3 The thickened oil sewage treatment device comprises:

[0044] a sewage treatment tank 1;

[0045] a sludge comprising a heavy carrier, arranged at one side of the bottom of the sewage treatment tank 1;

[0046] an aeration device 2 arranged above the sludge;

[0047] a plug flow device 11 arranged at the bottom of the sewage treatment tank 1;

[0048] a sewage inlet 12 arranged at one side of the sewage treatment tank 1 and above the aeration device 2;

[0049] a sewage outlet 13 arranged at the other side of the sewage treatment tank 1 and above the aeration device 2.

[0050] The aeration device 2 is a conventional device in the art.

[0051] In the present application, the aeration device 2 comprises a blower 21 and an aeration pipe 22, and the aeration pipe 22 is provided with an aeration port 222. The aeration pipe 22 is arranged above the bottom of one side of the sewage treatment tank 1, and the blower 21 is arranged outside the sewage treatment tank 1 and communicates with the aeration pipe 22, and the aeration pipe 22 aerates the sewage treatment tank 1 through the aeration port 222.

[0052] The heavy carrier is a conventional material in the art. The heavy carrier can provide a place for the growth of microorganisms and adsorb pollutants and microbial metabolites in the sewage.

[0053] By forming sludge in a low-dissolved oxygen content environment, the sludge itself has poor mobility and low efficiency of material exchange with the outside environment, and is prone to form an anaerobic environment.

[0054] The heavy pollutants in the sewage themselves have a tendency to deposit and form sludge. The heavy carrier can accelerate the formation of sludge and further enrich the anaerobic microbial community.

[0055] The reactions occurring in the sludge include but are not limited to decomposition of long-chain, cyclic, benzene-like organic pollutants; denitrification. These reactions can increase the biodegradability of the sewage.

[0056] As an example, the heavy carrier can be activated carbon. After a large number of microorganisms are produced on the surface of the activated carbon and pollutants and microbial metabolites are adsorbed, the density of the activated carbon increases and it deposits at the bottom of the sewage treatment tank 1 to form sludge.

[0057] The presence of the aeration device 2 makes the dissolved oxygen content above the aeration device 2 in the sewage treatment tank 1 significantly higher than that below. This makes the sewage treatment tank 1 divided into a high-dissolved oxygen content region and a low-dissolved oxygen content region, the high-dissolved oxygen content region being conducive to aerobic biochemical reactions of the sewage, and the low-dissolved oxygen content region being conducive to anaerobic biochemical reactions of the sludge.

[0058] The plug flow device 11 is used to push the sludge from one side of the bottom of the sewage treatment tank 1 to the other side. After the sludge moves to the other side of the sewage treatment tank 1, it is mixed with the sewage after the aerobic biochemical reaction. The mixed sewage is discharged through the sewage outlet 13.

[0059] As the plug flow device 11 pushes the sludge, the sludge at the bottom of the sewage treatment tank 1 gradually moves from one side of the sewage treatment tank 1 to the other side. In this process, as the oxygen in the sludge is continuously consumed, the dissolved oxygen content continuously decreases, and the environment in the sludge gradually transitions from an aerobic environment to a facultative environment, and then to an anaerobic environment. Please refer to Figure 2The sludge can be sequentially divided into an aerobic zone, a facultative zone and an anaerobic zone from one side to the other side of the sewage treatment tank 1 according to the dissolved oxygen content. The upper part of the aeration device 2 is a high-dissolved-oxygen zone. Figure 2 The direction of the arrow points to the direction of movement of the sludge or sewage. The coexistence of the aerobic, facultative and anaerobic states is conducive to the formation of a comprehensive microbial system and the enhancement of microbial diversity. The high-dissolved-oxygen zone can efficiently decompose organic pollutants and total phosphorus.

[0060] The present application forms sludge by using a heavy carrier, deposits the sludge at the bottom of the sewage treatment tank 1, separates the sludge and the sewage by the aeration device 2, and makes the dissolved oxygen content in the sludge lower and the dissolved oxygen content in the sewage higher, which enables the simultaneous performance of aerobic and anaerobic biochemical reactions in the sewage treatment tank 1 and realizes effective treatment of the heavy oil sewage.

[0061] In addition, the present application realizes a two-phase (sewage phase and sludge phase) three-state (aerobic, facultative and anaerobic) biochemical treatment system in the same structure, can realize a comprehensive process link, reduces the process sequence, and simultaneously reduces the process land area.

[0062] In some embodiments of the present application, please refer to Figure 1 , Figure 3 The heavy oil sewage treatment device further comprises a first-stage secondary sedimentation tank 3, and the sewage outlet 13 is in communication with the first-stage secondary sedimentation tank 3.

[0063] In some embodiments of the present application, the first-stage secondary sedimentation tank 3 is connected with a first water purifying agent adding device 31.

[0064] The first water purifying agent adding device 31 is used for adding a water purifying agent to the first-stage secondary sedimentation tank 3.

[0065] In some embodiments of the present application, the heavy oil sewage treatment device further comprises a second-stage aerobic tank 4 and a second-stage secondary sedimentation tank 5 in communication, the first-stage secondary sedimentation tank 3 is in communication with the second-stage aerobic tank 4, and the second-stage secondary sedimentation tank 5 is in communication with the sewage inlet 12.

[0066] The sewage discharged from the sewage outlet 13 can sequentially pass through the first-stage secondary sedimentation tank 3, the second-stage aerobic tank 4 and the second-stage secondary sedimentation tank 5 and then be recycled back to the sewage treatment tank 1, so as to further deepen the aerobic biochemical reaction.

[0067] In some embodiments of the present application, the first-stage secondary sedimentation tank 3 and the second-stage aerobic tank 4 are in communication through a first pumping mechanism 32.

[0068] The first pumping mechanism 32 can pump the sewage in the first-stage secondary sedimentation tank 3 to the second-stage aerobic tank 4.

[0069] In some embodiments of the present application, the secondary secondary sedimentation tank 5 is connected with the sewage inlet 12 through a second pumping mechanism 51.

[0070] The second pumping mechanism 51 can pump the sewage in the secondary secondary sedimentation tank 5 to the sewage inlet 12.

[0071] In some embodiments of the present application, the secondary secondary sedimentation tank 5 is connected with a second water purifying agent adding device 52.

[0072] The second water purifying agent adding device 52 is used to add water purifying agent to the secondary secondary sedimentation tank 5.

[0073] In some embodiments of the present application, the secondary aerobic tank 4 is connected with a heavy carrier adding device 41.

[0074] The heavy carrier adding device 41 is used to add heavy carrier to the secondary aerobic tank 4. The heavy carrier adding in the secondary aerobic tank 4 can adsorb more oxygen. After being pumped back to the sewage treatment tank 1 by the second pumping mechanism 51, the heavy carrier quickly deposits to the bottom of one side of the sewage treatment tank 1 to form sludge of the aerobic zone. This is conducive to increasing the dissolved oxygen content of the aerobic zone, so that the dissolved oxygen content can form a gradient distribution mode of the aerobic zone, the facultative zone and the anaerobic zone.

[0075] In some embodiments of the present application, the secondary aerobic tank 4 is provided with an aeration pipe 22, and the aeration pipe 22 in the sewage treatment tank 1 and the aeration pipe 22 in the secondary aerobic tank 4 are connected with the same air blowing device 21.

[0076] In some embodiments of the present application, the heavy oil sewage treatment device further comprises a sludge circulation pipe 14, and the sludge circulation pipe 14 is arranged at the bottom of one side of the sewage treatment tank 1, and the primary secondary sedimentation tank 3 is connected with the sludge circulation pipe 14.

[0077] The sewage discharged from the sewage outlet 13 can be circulated back to the sewage treatment tank 1 after the primary secondary sedimentation tank 3, so as to further deepen the anaerobic biochemical reaction.

[0078] In some embodiments of the present application, the primary secondary sedimentation tank 3 is connected with the sludge circulation pipe 14 through a third pumping mechanism 33.

[0079] The third pumping mechanism 33 can pump the sewage in the primary secondary sedimentation tank 3 to the sludge circulation pipe 14.

[0080] In a second aspect, the embodiments of the present application provide a heavy oil sewage treatment method, and the heavy oil sewage treatment method is realized by the heavy oil sewage treatment device of the first aspect. The heavy oil sewage treatment method comprises the following steps.

[0081] S1: sewage is introduced into the sewage treatment tank 1 from the sewage inlet 12, and heavy carriers are added into the sewage treatment tank 1, so that the heavy carriers form sludge;

[0082] S2: the aeration device 2 is operated to increase the oxygen content of the sewage above the aeration device 2, so that the sewage above the aeration device 2 undergoes aerobic biochemical reaction;

[0083] S3: the sludge below the air permeation device undergoes anaerobic biochemical reaction;

[0084] S4: the sludge at the bottom of the sewage treatment tank 1 is pushed to the upper part of the sewage treatment tank by the push-flow device 11, mixed with the sewage after aerobic biochemical reaction to form primary treated sewage, and discharged through the sewage outlet 13.

[0085] In some embodiments of the present application, the primary treated sewage enters the secondary aerobic tank 4 for aerobic biochemical reaction after entering the primary secondary sedimentation tank 3 through the sewage outlet 13, and then enters the secondary secondary sedimentation tank 5 and circulates back to the sewage treatment tank 1 through the sewage inlet 12.

[0086] In some embodiments of the present application, the primary treated sewage enters the secondary aerobic tank 4 for aerobic biochemical reaction after entering the primary secondary sedimentation tank 3 through the sewage outlet 13, and then enters the secondary secondary sedimentation tank 5 and circulates back to the sewage treatment tank 1 through the sewage inlet 12.

[0087] In some embodiments of the present application, when the sewage is treated in the sewage treatment tank 1,

[0088] The hydraulic retention time is 13-15h; and / or,

[0089] The COD load is 10.8-16.8kg / (m 3 ·d); and / or,

[0090] The liquid phase pH value is 7.0-7.5; and / or,

[0091] The water temperature is 25-30℃; and / or,

[0092] The suspended sludge concentration is 11000-13000mg / L.

[0093] In some embodiments of the present application, the dissolved oxygen concentration of the sewage above the aeration device 2 is 6-8mg / L; and / or,

[0094] The dissolved oxygen concentration in the anaerobic environment below the aeration device 2 is less than 0.2mg / L.

[0095] In some embodiments of the present application, the reflux ratio of the high-dissolved-oxygen environment in the sewage treatment tank 1 is 120%-135%; and / or,

[0096] Anaerobic internal recycle reflux ratio 85% - 100%.

[0097] Various embodiments of the application can exist in a range format; it should be understood that the description in range format is merely for convenience and brevity and should be taken in its entirety to describe all the possible subranges; therefore, every number that falls within a range should be considered as if it were specifically identified in the range; for example, a range of "1 to 6" should be considered to include any number from 1 to 6, for example, 1, 2, 3, 4, 5, and 6, individually; as well as in combination. Also, the phrase "at least two" means two or more; for example, "at least two instruments" means two or more instruments.

[0098] In this application, the positional words such as "upper" and "lower" are specifically the directions of the drawing surface in the drawings unless otherwise stated. In addition, in the description of the specification, the terms "comprise", "include" and the like mean "including but not limited to". Moreover, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles or devices including a series of elements not only include those elements, but also include other elements not explicitly listed or inherent to such processes, methods, articles or devices. Without more limitations, the elements defined by the statement "comprise" do not exclude the presence of other identical elements in the processes, methods, articles or devices including the elements. In this text, the relationship terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. In this text, the "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the following cases: A exists alone, A and B exist together, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of the three associated objects can exist alone, or any at least two of them exist together, for example, for A, and / or B, and / or C, it means that any one of A, B and C exists alone, or any two of them exist together, or all three of them exist together. In this text, "at least one" means one or more, and "multiple" means two or more. "At least one", "at least one of the following" or the like means any combination of the items, including any combination of single or multiple items. For example, "at least one of a, b or c", or "at least one of a, b and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b and c can be single or multiple.

[0099] The above description is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A device for treating heavy oil wastewater, characterized in that, The heavy oil wastewater treatment device includes: A sewage treatment pond; Sludge, including a heavy carrier, is placed at the bottom of one side of the wastewater treatment tank, and the heavy carrier is activated carbon; An aeration device is installed above the sludge to separate the sludge and wastewater, resulting in a lower dissolved oxygen content in the sludge and a higher dissolved oxygen content in the wastewater. A flow-pushing device is installed at the bottom of the sewage treatment tank to push the sludge from one side of the bottom of the sewage treatment tank to the other side; The wastewater inlet is located on one side of the wastewater treatment tank and above the aeration device; The wastewater outlet is located on the other side of the wastewater treatment tank and above the aeration device.

2. The apparatus according to claim 1, wherein The heavy oil wastewater treatment device also includes a primary secondary sedimentation tank, and the wastewater outlet is connected to the primary secondary sedimentation tank.

3. The apparatus according to claim 2, wherein The heavy oil wastewater treatment device also includes a secondary aerobic tank and a secondary sedimentation tank that are connected to each other. The primary sedimentation tank is connected to the secondary aerobic tank, and the secondary sedimentation tank is connected to the wastewater inlet.

4. The heavy oil wastewater treatment device according to claim 2, characterized in that, The heavy oil wastewater treatment device also includes a sludge circulation pipe, which is located at the bottom of one side of the wastewater treatment tank, and the primary sedimentation tank is connected to the sludge circulation pipe.

5. A method for treating heavy oily wastewater, characterized in that, The method for treating heavy oily wastewater is implemented using the heavy oily wastewater treatment apparatus according to any one of claims 1-4, and the method for treating heavy oily wastewater includes the following steps: Wastewater is introduced into the wastewater treatment tank from the wastewater inlet, and heavy carriers are added into the wastewater treatment tank to form sludge. The aeration device is operated to increase the oxygen content of the wastewater above the aeration device, so that the wastewater above the aeration device can undergo aerobic biochemical reactions. The sludge below the aeration device undergoes an anaerobic biochemical reaction. The sludge at the bottom of the wastewater treatment tank is pushed to the top of the wastewater treatment tank by the propulsion device, and mixed with the wastewater that has undergone aerobic biochemical reaction to form pre-treated wastewater, which is then discharged through the wastewater outlet. When the wastewater is treated in the wastewater treatment pond The hydraulic retention time is 13-15 hours; and / or, COD loading is 10.8-16.8 kg / (m³·d); and / or, The liquid phase pH is 7.0-7.5; and / or, The water temperature is 25-30℃; and / or, The suspended sludge concentration was 11,000-13,000 mg / L; The high dissolved oxygen environment reflux ratio in the wastewater treatment pond is 120%-135%; the anaerobic internal circulation reflux ratio is 85%-100%.

6. The method for treating heavy oily wastewater according to claim 5, characterized in that, The pretreated wastewater enters the primary sedimentation tank through the wastewater outlet, then enters the secondary aerobic tank for aerobic biochemical reaction, and subsequently enters the secondary sedimentation tank again, before being circulated back to the wastewater treatment tank through the wastewater inlet.

7. The method for treating heavy oily wastewater according to claim 5, characterized in that, The pre-treated wastewater enters the primary secondary sedimentation tank through the wastewater outlet and then circulates back to the wastewater treatment tank through the sludge circulation pipe.

Images