MSBR process sewage treatment system

Abstract

The utility model belongs to the technical field of sewage treatment, and particularly relates to an MSBR process sewage treatment system which comprises an anaerobic tank, a first-stage anoxic tank, an SBR tank, a second-stage anoxic tank, a second-stage aerobic tank and a sedimentation tank which are sequentially communicated, the SBR tank is used for realizing water inlet and aeration / stirring effects, and the sedimentation tank and the anaerobic tank are connected with a concentrated sludge return pipeline. A sludge concentration area is arranged at the bottom of the sedimentation tank. The method has the advantages that the advantage that the SBR process only uses the SBR pool to intermittently aerate in turn is fully exerted, the defect that energy consumption is increased due to the fact that high total nitrogen removal rate of the AAO process requires high reflux ratio is overcome, meanwhile, the concentration of sludge returned from the concentrated sludge return pipeline is increased, the sludge reflux ratio is reduced to 40%-60%, secondary sludge reflux is not needed, and the cost is reduced. And the effect of sludge backflow operation can be realized at one time.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment, in particular to an MSBR process sewage treatment system. Background Art

[0002] The MSBR sewage treatment process is a modified SBR process, also known as a modified sequencing batch reactor, with the English name Modified Sequencing Bath Reactor. From the perspective of process characteristics, MSBR is actually equivalent to the series connection of AAO process and SBR process. Therefore, it has good phosphorus and nitrogen removal effects at the same time and is considered to be the latest and most intensive new sewage treatment process at present. The system has great advantages in terms of reliability, energy conservation, operation cost reduction, land saving, etc.

[0003] In related technologies, a typical MSBR system consists of 8 cells and can operate continuously at a constant water level. The essence of its process flow is the same as that of the traditional AAO+SBR process. As shown in the appendix Figure 1 Unit 1 and Unit 7 are SBR tanks, Unit 2 is a sludge thickening tank (mud-water separation tank), Unit 3 is a pre-anoxic tank, Unit 4 is an anaerobic tank, Unit 5 and 5A are anoxic tanks, and Unit 6 is a main aeration aerobic tank. A typical MSBR is equivalent to the series connection of AAO process and SBR process, but it fails to fully utilize the advantage of the SBR process that only intermittent aeration in the SBR tank in turn can solve the defect that the high total nitrogen removal rate of the AAO process requires a high reflux ratio, thus increasing energy consumption; since Unit 1 and Unit 7 are SBR tanks integrating multiple processes such as influent, reaction (anaerobic, anoxic, aerobic), sedimentation and effluent, rather than specially designed and constructed secondary sedimentation tanks, there is no sludge thickening area at the bottom of the tank, so the concentration of the returned sludge is low and the return flow is large. Usually, a separate sludge thickening tank needs to be set up for thickening and the thickened sludge needs to be returned twice, which not only increases the returned sludge equipment, but also increases the complexity of operation management and energy consumption.

[0004] Therefore, the prior art needs to be improved. Content of the Utility Model

[0005] In order to make up for the deficiencies of the prior art, this application proposes an MSBR process sewage treatment system.

[0006] The technical solution adopted by the utility model to solve its technical problems is as follows:

[0007] An MSBR process sewage treatment system includes an anaerobic tank, a first anoxic tank, an SBR tank, a second anoxic tank, a second aerobic tank, and a sedimentation tank connected in sequence. There are two SBR tanks, and the two SBR tanks are used to achieve the function of intermittent aeration in turn for the influent. A concentrated sludge return pipeline is connected between the sedimentation tank and the anaerobic tank, and a sludge thickening area is arranged at the bottom of the sedimentation tank.

[0008] Preferably, a mixed liquor return pipeline is connected between the water outlet point of the second aerobic tank and the first anoxic tank.

[0009] Preferably, the mixed liquor return ratio of the mixed liquor return pipeline is 40%-60%.

[0010] Preferably, it further includes a degassing mixing tank. The degassing mixing tank is connected in series between the SBR tank and the second anoxic tank. A stirrer is arranged in the degassing mixing tank, and the stirrer is used to remove the remaining dissolved oxygen during the aeration process.

[0011] In summary, the technical solution of the present invention has the following beneficial technical effects:

[0012] The MSBR system of the present invention splits the sedimentation and effluent processes in the SBR tank, separately sets a sedimentation tank connected to the second aerobic tank, and arranges a sludge thickening area at the bottom of the sedimentation tank to increase the concentration of the sludge returned from the concentrated sludge return pipeline, so as to reduce the sludge return ratio to 40%-60%. Then, there is no need for secondary sludge return, and the operation of sludge return can be achieved at one time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 It is a schematic plan view of the MSBR system in the prior art;

[0015] Figure 2 It is a schematic plan view of the MSBR system in the embodiment of the present application.

[0016] Explanation of reference numerals: 1, anaerobic tank; 2, first anoxic tank; 3, SBR tank; 4, second anoxic tank; 5, second aerobic tank; 6, sedimentation tank; 7, mixed liquor return pipeline; 8, concentrated sludge return pipeline; 9, degassing mixing tank; 10, stirrer; 11, submersible pump. DETAILED DESCRIPTION OF THE INVENTION

[0017] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0018] The embodiments of the present application disclose a sewage treatment system using the MSBR process.

[0019] Refer to Figure 2, the MSBR process sewage treatment system includes an anaerobic tank 1, a first anoxic tank 2, an SBR tank 3, a second anoxic tank 4, a second aerobic tank 5, and a sedimentation tank 6. Specifically, the anaerobic tank 1, the first anoxic tank 2, the SBR tank 3, the second anoxic tank 4, the second aerobic tank 5, and the sedimentation tank 6 are connected in sequence. Stirrers 10 are provided in the anaerobic tank 1, the first anoxic tank 2, the second anoxic tank 4, and the SBR tank 3. The structural form of the stirrer 10 is a blade. The sedimentation tank 6 is provided with a concentrated sludge return pipeline 8 connected to the anaerobic tank 1. The sludge is returned from the sedimentation tank 6 to the anaerobic tank 1 through a submersible pump 11. At the same time, a sludge thickening area is provided at the bottom of the sedimentation tank 6. The sludge thickening area is used to thicken the sludge to reduce the moisture content of the sludge and reduce the volume of the sludge, thereby reducing the subsequent treatment cost. At the same time, a submersible pump 11 for discharging the excess sludge is also provided in the sedimentation tank 6. In this application, there are two SBR tanks 3, and the two SBR tanks 3 are arranged in parallel. The SBR tank 3 has the functions of water inlet and intermittent aeration in turn. And when sewage treatment is carried out, the two SBR tanks 3 are aerated intermittently in turn, that is, the two SBR tanks 3 play the role of aerobic nitrification tank or anoxic denitrification tank in turn. At the same time, the two SBR tanks 3 can also be set to be intermittently fed in turn, that is, they operate in a way that only water is fed during the period when they play the role of anoxic denitrification tank and no water is fed during the period when they play the role of aerobic nitrification tank. Through the sedimentation tank 6 and the sludge thickening area provided at the bottom of the sedimentation tank 6, the precipitation, water outlet process and reaction process in the existing SBR tank 3 are split and adjusted to a series combination of AAO + SBR (water inlet, stirring / aeration) + AO + precipitation and water outlet. Among them, AAO is the aerobic state of the anaerobic tank 1 + the first anoxic tank 2 + the SBR tank 3 during the aeration period, and AO is the second anoxic tank 4 + the second aerobic tank 5. And the "precipitation and sedimentation" water outlet process in the SBR tank 3 is carried out separately in a conventional manner, a sludge thickening area is set, and the series combination is adjusted to the last process of the secondary biochemical treatment section, so as to increase the concentration of the sludge returned from the concentrated sludge return pipeline 8. In this way, the sludge return ratio is directly reduced from 150% - 250% to 40% - 60%, then there is no need to carry out secondary sludge return, and the operation of sludge return can be achieved at one time. At the same time, a series of non-standard equipment such as an air control weir can be cancelled.

[0020] Furthermore, a mixed liquid return pipeline 7 is provided between the water outlet point of the second aerobic tank 5 and the first anoxic tank 2 and is connected. The mixed liquid is returned from the second aerobic tank 5 to the first anoxic tank 2 through a submersible pump 11. The mixed liquid return pipeline 7 is used to return the mixed liquid (mainly supplying nitrate nitrogen) in the second aerobic tank 5 to the first anoxic tank 2. And in this embodiment, the mixed liquid return ratio is reduced from 400% - 450% to 40% - 60%, preferably 50%. Specifically, the flow rate is controlled by the selected submersible pump 11. Its functions are as follows:

[0021] 1. The raw water after reacting in the anaerobic tank 1 and the first-stage anoxic tank 2 can be promptly sent into the two SBR tanks 3 for mixing reaction, and at the same time, the entry of the first type of high-quality carbon source (easily degradable anaerobic fermentation products such as volatile fatty acids and alcohols) into the SBR tanks 3 and their being oxidized by aeration can be minimized or avoided.

[0022] 2. Give full play to the unique advantages of the SBR process, which can achieve large-scale mixed liquor reflux only by intermittent aeration in turn, can locally provide sufficient nitrate nitrogen, and does not require reflux. This can further enhance the mixing and stirring effects of the mixed liquor, and at the same time, it can save investment, reduce energy consumption, and lower the operation and maintenance costs.

[0023] 3. It can effectively ensure that the total nitrogen (TN) of the effluent from the secondary biochemical treatment section is controlled within a reasonable range, and ensure the stable compliance of ammonia nitrogen (NH3-N).

[0024] Furthermore, a degassing mixing tank 9 is provided between the SBR tank 3 and the secondary anoxic tank 4. That is, after the intermittent aeration of the two SBR tanks 3 in turn ends and before entering the secondary anoxic tank 4, the degassing mixing tank 9 is respectively connected to the SBR tank 3 and the secondary anoxic tank 4. And a stirrer 10 is provided in the degassing mixing tank 9. The stirrer 10 is a submersible high-speed stirrer 10. When the sewage moves into the degassing mixing tank 9, the sewage is vigorously stirred by the high-speed rotating stirrer 10. Through the high-speed stirring of the sewage, the dissolved oxygen in the sewage is separated from the sewage, and the degassed mixed liquor flows into the secondary anoxic tank 4 to strive to make the most of the raw water carbon source to ensure the denitrification effect of the entire MSBR system. At the same time, the residence time of the sewage in the degassing mixing tank 9 is 30 minutes.

[0025] In this embodiment, the MSBR system in this solution still consists of 8 cells, which are, in the order of the process flow: anaerobic tank 1, first-stage anoxic tank 2, two SBR tanks 3, degassing mixing tank 9, secondary anoxic tank 4, secondary aerobic tank 5, sedimentation tank 6.

[0026] One operating cycle of the MSBR system in this solution is 2 time periods. Time period 1: 120 minutes; Time period 2: 120 minutes. That is, each time period is simplified to half a cycle, and at the same time, appropriate adjustments are made in actual operation in combination with the fluctuations of water quality and water volume and the temperature changes in winter and summer.

[0027] The sewage enters from the anaerobic tank 1 of the MSBR system, and the flow directions in the two time periods are as shown in the following table:

[0028]

[0029] In period 1, one of the SBR tanks 3 functions as an aerobic tank, and the other SBR tank 3 functions as an anoxic tank; while in period 2, one of the SBR tanks 3 changes from functioning as an aerobic tank to functioning as an anoxic tank, and the other SBR tank 3 changes from functioning as an anoxic tank to functioning as an aerobic tank.

[0030] The above are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. An MSBR process sewage treatment system, characterized in that: It includes an anaerobic tank, a first anoxic tank, an SBR tank, a second anoxic tank, a second aerobic tank and a sedimentation tank that are connected in sequence. There are two SBR tanks, and the two SBR tanks are used to achieve the functions of water inlet and intermittent aeration in turn. A concentrated sludge return pipeline is connected between the sedimentation tank and the anaerobic tank, and a sludge thickening area is arranged at the bottom of the sedimentation tank.

2. The sewage treatment system using the MSBR process according to claim 1, characterized in that: A mixed liquor return pipeline is connected between the water outlet point of the second aerobic tank and the first anoxic tank.

3. The sewage treatment system by MSBR process according to claim 2, characterized in that: The mixed liquor return ratio of the mixed liquor return pipeline is 40%-60%.

4. An MSBR process sewage treatment system according to claim 1, characterized in that: It also includes a degassing mixing tank, which is connected in series between the SBR tank and the second anoxic tank. A stirrer is arranged in the degassing mixing tank, and the stirrer is used to remove the remaining dissolved oxygen during the aeration process.

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