OA16699A - Apparatus and method for biological sewage treatment. - Google Patents

Abstract

The present invention relates to an apparatus for biological sewage treatment, including a concentrated mixed liquor driving device that uses a gas to drive a concentrated mixed liquor to flow. The present invention further relates to a method for biological sewage treatment, including a step of using a gas to drive a concentrated mixed liquor to flow. The gas can be an oxygen-containing gas, especially an oxygen-containing aeration gas after aeration treatment. The apparatus and method of the present invention can sufficiently utilize the energy and oxygen of the aeration gas, so that the energy consumption and maintenance cost of whole apparatus are reduced, biological sewage treatment effects are improved, and sludge floating is prevented. In addition, the apparatus of present invention has advantages of high performance, energy saving, high reliability, and good capability of miniaturization.

Description

The présent invention relates lo an apparatus for biological sewage treatment, comprising a concentrated mixed liquor driving device that uses a gas to drive a concentrated mixed liquor to flow; the présent invention further relates to a method for biological sewage treatment, comprising using a gas to drive a concentrated mixed liquor to flow.

Background Art

In a common apparatus for biological sewage treatment (also called as “sewage biO'lreatmenL”, sewage biological treatment or “biological treatment of sewage”), a mixed liquor is acratcd in an aération tank, then separated in a sédimentation tank lo form a supematant (also called as “water outflow”) and a concentrated mixed liquor (also called as sludge or “active sludge”); and, at least a part of Lhe concentrated mixed liquor retums to lhe aération tank (also called as “sludge relum) and is mixed with a sewage feed (also called as “water inflow), Usually, sludge rctum is achieved by using a sludge relurn pump (e.g., a centrifugal pump). However, sludge retum pump needs extra energy and frequent maintenance. In addition, an electric sludge rctum pump needs further insulating treatment to prevent leakage of elcctricity. Titus, a sludge retum pump has lo be disposed at a spécifie place, which restricts the flexibilily of process lay-out, and usually needs a large amount of pipelines for connection, thereby increasing cquipment investment and reducing reliability of the «

whole apparatus. These problems are especially serious in tower-type biological sewage treatment apparatus which has a small floor urea and a great height.

Chinese patent application CN102372379A discloses a tower-type biological sewage treatment apparatus, comprising an upflow sludge bed reactor, an aérobic reactor disposed above the upflow sludge bed reactor, and a separalor disposed in upper part of the aérobic reactor, in which both of aération gas and aerated mixed liquor from the aérobic reactor enter a gas-liquor separating tank, and the separated mixed liquor enters a solid-liquor separating zone and is separated to form a supematant and a concentrated mixed liquor, and lhe concentrated mixed liquor retums to the aérobic reactor and is mixed with a sewage feed and aerated to form the aerated mixed liquor.

However, when separating an aération gas and a mixed liquor, or separating a mixed liquor to form a supematant and a concentrated mixed liquor, a separating device or method in the art is usually unable to achicve desired séparation cffccts. Especially, in a tower-type biological sewage treatment apparatus with limited volume and height, lhe séparation to form a supematant and a concentrated mixed liquor in a sédimentation tank is difficult, while poor séparation even results in sludge floating and breaks sewage treatment process.

Further, during biological sewage treatment process, an air blower for aération is usually a primary energy-consuming device, and an aération gas is generally discharged directly to atmosphère after aération treatment, so thaï the energy and oxygen in lhe aération gas are not sufficiently utilized, which results in higher energy consumption in biological sewage treatment.

Hence, apparatus and method for biological sewage treatment with lower energy consumption, high reliability and high cfficiency are still in need.

Contents of the Invention

One objective of the présent invention is to provide an apparatus or method for biological sewage treatment so as to solve the above problems in the art. Titus, the présent invention especially provides the following technical solutions:

l. An apparatus for biological sewage treatment, comprising a concentrated

mixed liquor driving device that uses a gas to drive a concentrated mixed liquor to flow.

2. The apparatus for biological sewage treatment according to lhe technical solution l, wherein the concentrated mixed liquor driving device is disposed to allow the gas to contact with the concentrated mixed liquor.

3. The apparatus for biological sewage treatment according to die tcchnical solution I or 2, wherein lhe concentrated mixed liquor driving device comprises a guiding tube in which the gas und the concentrated mixed liquor enter and are mixed, a gas inlet and a concentrated mixed liquor inlet are set at a lower part of the guiding

I0 tube, a gas-liquor mixture conveying section is set at a middle part of lhe guiding tube, and a gas-liquor mixture outlet is set at a upper part of die guiding tube.

4. The apparatus for biological sewage treatment according to any one of the tcchnical solutions l-3, wherein the concentrated mixed liquor driving device further comprises a gas-liquor separating device that is fluidly connected with Lhe gas-liquor mixture outlet.

5. The apparatus for biological sewage treatment according to any one of the preceding technical solutions, further comprising an aération section to provide an aération gas as the gas.

6. The apparatus for biological sewage treatment according to any one of the 20 preceding technical solutions, further comprising a sédimentation section to provide the concentrated mixed liquor.

7. The apparatus for biological sewage treatment according to any one of the preceding technical solutions, further comprising an anaérobie treatment section, a sédimentation section and an aération section, wherein lhe anaérobie treatment section is disposed to receive a sewage feed and the concentrated mixed liquor from the concentrated mixed liquor driving device and to perform anaérobie treatment so as to obtain an anaérobie trcatinenl mixed liquor, Lhe aération section is disposed to receive the anaérobie treatment mixed liquor and to allow it to contact with an aération gas to obtain an aération treatment mixed liquor, the sédimentation section is disposed to 30 receive lhe aération treatment mixed liquor which is separated to obtain a supematant and the concentrated mixed liquor, and the concentrated mixed driving device is

disposed to receive the concentrated mixed liquor and to drive the concentrated mixed liquor to flow by using the aération gas from the aération section.

8. The apparatus for biological sewage treatment according to technical solution

7, wherein the aération section has a gas-liquor separating device to separate the aération treatment mixed liquor and the aération gas, the gas-liquor separating device is fluidly connected with tlie sédimentation section to allow the sédimentation section to receive die aération treatment mixed liquor, and the gas-liquor separating device is disposed to prevent the aération gas from entering the sédimentation section.

9. The apparatus for biological sewage treatment according to technical solution

7, wherein the anaérobie treatment section, the sédimentation section and the aération section arc disposed so that the apparatus for biological sewage treatment forms a horizontal type apparatus for biological sewage treatment.

10. The apparatus for biological sewage treatment according to any one of the preceding technical solutions, wherein at least a part of the apparatus for biological sewage treatment is disposed below or above the ground, or the apparatus for biological sewage treatment is disposed on a movable platform.

11. The apparatus for biological sewage treatment according to the technical solution I, wherein the apparatus for biological sewage treatment is a tower-type apparatus for biological sewage treatment which has a sédimentation chamber, tlie concentrated mixed liquor driving device is a pneumalic mixed liquor clevating device which is used to elevate a concentrated mixed liquor in the sédimentation chamber by using the gas.

12. The apparatus for biological sewage treatment according to the technical solution 11, wherein die pneumalic mixed liquor clevating device comprises a subslantivcly vertical liquor elevating tube for drawing tlie concentrated mixed liquor and a gas guiding tube which is fluidly connected with the liquor clevating tube and used for introducing the gas into the liquor elevating tube.

13. The apparatus for biological sewage treatment according to the technical solution 12, wherein the liquor elevating tube has un inlet for drawing the concentrated mixed liquor and an outlet for discharging the gas and tlie concentrated mixed liquor, and the gas guiding tube is connected with a middle or lower part of tlie liquor clcvaling lube.

14. The apparatus for biological sewage treatment according to the technical solution 13, wherein a sludge collecting channel is set at the bottom of the sédimentation chamber, and the inlet of the liquor elevating tube extends into the sludge collecting channel.

15. The apparatus for biological sewage treatment according lo any one of the technical solutions H-14, further comprising a gas-liquor separating tank for separating the concentrated mixed liquor and the gas from the pneumalic mixed liquor clcvaling device.

16. The apparatus for biological sewage treatment according to the technical solution 15, wherein the gas-liquor separating tank is fluidly connected with the outlet of the liquor elevating tube.

17. The apparatus for biological sewage treatment according to any one of the technical solutions 11-14, further comprising an aération chamber, wherein the aération chamber hus a gas collecting hood lo collcct an aération gas in the aération chamber, and at least of the gas is the aération gas from Lhe gas collecting hood.

18. The apparatus for biological sewage treatment according lo the technical solution 17, wherein the gas collecting hood is fluidly connected with the gas guiding tube.

19. The apparatus for biological sewage treatment according to the technical solution 17, wherein lhe aération chamber further has a liquor collecting tank lo collcct a mixed liquor in lhe aération chamber, the sédimentation chamber is fluidly connected with the liquor collecting tank, and at least part of the concentrated mixed liquor in the sédimentation chamber is derived from a mixed liquor of the liquor collecting tank.

20. The apparatus for biological sewage treatment according lo the technical solution 17, further comprising a division plate disposed between the aération chamber and the sédimentation chamber.

21. The apparatus for biological sewage treatment according to the technical solution 20, wherein the division plate defines a roof of die liquor collecting tank, and the corresponding part of the division plate has a hole or a pipeline through which the

mixed üquor in the liquor collccting tank enters the sédimentation chamber.

22. Tiic apparatus for biological sewage treatment according to the technical solution 17, wherein a first concentrated mixed liquor relum pipe for introducing the concentrated mixed liquor of the gas-liquor separating tank into the aération chamber 5 is disposed between the gas-liquor separating tank and the aération chamber.

23. The apparatus for biological sewage treatment according to the technical solution I7, further comprising an anaérobie réaction chamber as disposed below the aération chamber, wherein a second concentrated mixed liquor relum pipe for introducing the concentrated mixed liquor of the gas-liquor separating tank into the 10 anaérobie reaction chamber is disposed between the gas-liquor separating tank and the anaérobie reaction chamber.

24. The apparatus for biological sewage treatment according to any onc of the preceding technical solutions, further comprising a power room or a power chamber and a heat exchanger, wherein lhe heat exchangcr heats a mixed liquor in the apparatus for biological sewage treatment by using a heat released from a power device in the power room.

25. The apparatus for biological sewage treatment according to lhe technical solution 24, wherein the power room and the heat exchangcr are disposed in the anaérobie réaction chamber and/or the aération chamber, the power room is inlemully equipped with the power device and has an air inlet fluidly connecting with atmosphère and an air outlet fluidly connecting with the heat exchanger, and a gas heated with the power device in the power room exchanges heat with the mixed liquor in lhe anaérobie reaction chamber and/or lhe aération chamber via the heat exchange.

26. The apparatus for biological sewage treatment according to the technical 25 solution 24, wherein the air inlet has a gas distributing device to control the distribution of a gas entering the power room.

27. The apparatus for biological sewage treatment according to the technical solution 25, wherein the power device is a pump and/or an air blower.

28. The apparatus for biological sewage treatment according to any one of the 30 technical solutions 24-27, wherein the heat exchanger is onc or more selected from spiral tube heat exchangers, straight tube heat exchangers or combinations thereof.

29. The apparatus for biological scwagc treatment according to any one of the lechnical solutions 24-28, wherein thc power room is further equippcd with an instrument, a switch and/or a valve for monitoring and controlling the apparatus for biological sewage treatment.

30. The apparatus for biological sewage treatment according to any one of the preceding lechnical solutions, further comprising a sludge lump breaking device in the sédimentation section or ihc sédimentation chambcr. In some embodiments of the présent invention, the sludge lump breaking device is an acrator or a gas distributor.

31. A method for biological sewage treatment, comprising using a gas to drive a concentrated mixed liquor lo flow. In some embodiments of the method for biological sewage ireatment according to the présent invention, thc method is performed by using the apparatus for biological sewage treatment according to any onc of the lechnical solutions I-30.

32. The method for biological sewage treatment according to technical solution 31, wherein at least part of the gas is an oxygen-containing gas, especially an aération gas.

33. The method for biological sewage Ireatment according to any one of tcchnical solutions 31-32, wherein the concentrated mixed liquor is from a sédimentation section.

34. The method for biological sewage treatment according to any one of technical solutions 31-33, further comprising introducing a sewage feed and the concentrated mixed liquor to an anaérobie treatment section to perform anaérobie treatment and obtain an anaérobie treatment mixed liquor, introducing the anaérobie treatment mixed liquor to an aération section and contacting with an aération gas to obtain an aération treatment mixed liquor, introducing thc aération treatment mixed liquor to a sédimentation section lo obtain a supematant and the concentrated mixed liquor, and using the aération gas collected from the aération section as thc gas to drive the concentrated mixed liquor to flow.

35. Thc method for biological sewage treatment according to any one of technical solutions 31-34, wherein the gas is an oxygen-containing gas, and the gas contacts with the concentrated mixed liquor.

36. A method for biological sewage treatment, comprising using the lower type apparatus for biological sewage treatment according to any onc of tcchnical solutions 11-30 to perform llic biological sewage treatment. In some embodiments, a gas is used to elevate a concentrated mixed liquor in a sédimentation section or sédimentation chamber. In some embodiments, the concentrated mixed liquor is elevated by a pneumatic mixed liquor elevating device using tlie gas. In further some embodiments, tlie concentrated mixed liquor is from a sédimentation chamber of a tower-type apparatus for biological sewage treatment.

37. The method for biological sewage treatment according to technical solution 36, wherein at least part of die gas is from an aération gas.

38. The method for biological sewage treatment according to technical solution 36, further comprising collecting a mixed liquor and an aération gas from an aération chamber, subjecling the mixed liquor to sédimentation treatment in the sédimentation device to obtain u supematant and a concentrated mixed liquor, and elevating the concentrated mixed liquor in lhe pneumatic mixed liquor elevating device using lhe aération gas.

39. The method for biological sewage treatment according to any one of technical solutions 36-38, further comprising separaling in a gas-liquor separating tank tlie aération gas and the concentrated mixed liquor from lhe pneumatic mixed liquor elevating device, and introducing at least part of the separated concentrated mixed liquor to lhe aération chamber.

40. The method for biological sewage treatment according to any one of technical solutions 36-38, further comprising subjecting a supematant in lhe sédimentation chamber to aération treatment periodically or when a sludge lump appears or is about to appcar in lhe supematant in the sédimentation chamber.

41. The method for biological sewage treatment according to any one of technical solutions 36-38, further comprising introducing at least part of the concentrated mixed liquor of tlie sédimentation chamber to an anaérobie réaction chamber.

42. The method for biological sewage treatment according to any one of technical solutions 36-38, further comprising a step of heating a mixed liquor using a heat relcased from power device. In some embodiments, the step is performed in an anaérobie reaction chamber, an aération chamber of a sédimentation chamber by using a heat ex changer.

In some embodiments of lhe apparatus for biological sewage treatment according to the présent invention, lhe concentrated mixed liquor driving device uses the gas to drive die concentrated mixed liquor to flow, wherein lhe gas can directly contact the concentrated mixed liquor, preferably the gas is mixed with lhe concentrated mixed liquor, so that lhe gas entraps the concentrated mixed liquor and floats upward, Üiereby driving the concentrated mixed liquor to flow. In some embodiments, the concentrated mixed liquor driving device is a concentrated mixed liquor retum device.

In some embodiments, the concentrated mixed liquor driving device comprises a guiding tube to receive the gas and lhe concentrated mixed liquor, lhe guiding tube has a gas inlet, a mixed liquor inlet and a gas-liquor mixture outlet. When the gas enters the guiding tube via the gas inlet and lhe concentrated mixed tube enters lhe guiding tube via lhe mixed liquor inlet, they arc mixed in the guiding tube to form a gas-liquor mixture which flows upward under the pressure and floating effects of the gas and then is discharged from the gas-liquor mixture outlet, so thaï the concentrated mixed liquor is driven to flow. In some embodiments, the guiding tube is tilted upward or stands substanlively vertically to facilitate the gas floating upward.

In some embodiments, lhe gas inlet of the guiding tube is fluidly connected with a suitable gas source, and a flow control valve is used to control the gas flow entering the guiding tube so as to control the flow of the concentrated mixed liquor. In some other embodiments, a flow control valve is set al upstream of the mixed liquor inlet of the guiding tube to control lhe flow of the concentrated mixed liquor that enters the guiding tube.

In some embodiments, lhe gas can be derived from any suitable gas sources, for examplc, the gas can be derived from an air comprcssor, an air blower, a storage tank of gas such as air, oxygen, nitrogen and inert gas. Preferably, the gas has a pressure greater than or equal to atmosphère pressure. Preferably, the gas is an oxygcn-containing gas. In some cases, aL least part of the gas is from an aération gas. The aération gas can be collected from any place of an aération device. Preferably, the aération gas is an aération gas released from an aerated mixed liquor and collected

ΙΟ from an upper part of an aération device. Usually, oxygen in an aération gas would not be depleted during aération treatment, so that the aération gas after aération treatment still contains oxygen. In some cases, an additional sludge relum pump is also used to drive the concentrated mixed liquor to flow. In some other cases, die additional sludge relum pump is driven by using the gas.

The inventors of the présent invention surprisingly find when an oxygcn-containing gas such as aération gas contacts with (preferably is mixed with) a concentrated mixed liquor so as to drive the concentrated mixed liquor to flow, the biological sewage treatment is unexpected improved in aspects of nitrogen removal and/or COD removal. Without being restricted with any known theory, die inventors believe dénitrification is enhaneed when die concentrated mixed liquor from a sédimentation section firstly contacts with an oxygen-containing gas (preferably an aération gas) and than is mixed with a sewage fccd, so that better effects of nitrogen removal and COD removal are achieved.

In some embodiments, the sédimentation section can bc any device that can be used to separate an aerated mixed liquor into a supemalant and a concentrated mixed liquor. Usually, the sédimentation section can be a sédimentation tank or sédimentation basin or sédimentation chamber. In some embodiments, tilted plates or tilted pipes could be set in the sédimentation section to enhance séparation effects.

The concentrated mixed liquor usually is formed in the lower part of the sédimentation section or tank or basin or chamber under sédimentation effects, in which sludge collecting channels could be set to enhance the sédimentation of the concentrated mixed liquor. The sédimentation section is fluidly connected with the concentrated mixed liquor driving device via a sludge retum pipe. One end of the sludge retum pipe can be sel in the lower part of the sédimentation section or tank or basin or chamber, preferably in a sludge collecting channel, to draw die concentrated mixed liquor. Another end of the sludge retum pipe can bc fluidly connected with the mixed liquor inlet of the concentrated mixed liquor deriving device.

In some embodiments, a mixed liquor distributor can be set in the sédimentation section so that the aerated mixed liquor from aération section is uniformly distributed in the sédimentation section and docs not disturb the séparation between the supematanL and the concentrated mixed liquor in the sédimentation section. In some

cases, an overflow well is set in upper part of lhe sédimentation section to discharge the supernatant as water outilow.

In the présent invention, the anaérobie treatment can be performed by substantively preventing a mixed Iiquor from contacting any oxygen-containing gas.

Usually, anaérobie state is achieved when there is substantively no dissolved oxygen, for cxample, die dissolved oxygen level is not higher than 0. Img/L. In some embodiments of the présent invention, the anaérobie treatment section can be any device that allows a mixed Iiquor of a concentrated mixed Iiquor and a sewage feed to undergo anaérobie treatment. In some cases, the anaérobie treatment can bc performed I0 by allowing the mixed Iiquor to flow slowly without aération. A suitable anaérobie treatment section can be a tank or basin or chamber in which the mixed Iiquor can flow in laminar, vertical or radial manner.

In some embodiments of the présent invention, üie aération section can be a device in which the mixed Iiquor can be subjeeled to aération treatment, for example, I5 an aération tank or aération basin or aération chamber. An aerator can be set in lhe aération section to enhance aération treatment. The aerator can be for example a spiral aerator, micropore aerator, platc-typc aerator, rotation mixing aerator, tube aerator, or jet aerator.

In some cases, the aération section is disposcd so that an anaérobie treatment 20 mixed Iiquor from the anaérobie treatment section cnlcrs a first end of the aération section, while die aération treatment mixed Iiquor after aération treatment is discharged from a second end of the aération treatment section and enters in the sédimentation section, where the first end and the second end of the aération section are disposed so thaï they are as l'ar as possible between each other to avoid channelÎng 25 and short circuiting. In some other cases, a baffle plate is set in the aération section to further cnhance aération treatment and avoid channeling and short circuiting.

In some cases, at least part, preferably ail, of the aération gas in the aération treatment section is collected and introduced to lhe concentrated mixed Iiquor driving device. In some cases, a gas-liquor separating device is set at the second end of lhe 30 aération section to separate aération gas and the aerated mixed Iiquor so that the acrated mixed Iiquor enters the sédimentation section while the aération gas does not enter the sédimentation section. The gas-liquor separating device can be any device

I2 that can perfonn the séparation between the aération gas and the acratcd mixed liquor. For cxample, the gas-liquor separating device can be one or more containers or tubes, which top has onc or more openings to allow the acratcd mixed liquor to enter the containers or tubes, and which bottom has a pipe fluidly connected with die sédimentation section to allow the acratcd mixed liquor in the containers or tubers to enter the sédimentation section. In some cases, the openings of the containers or tubers are immerged into lhe acratcd mixed liquor of the aération section to receive the acrated mixed liquor and prevent lhe aération gas entering lhe sédimentation section.

In some embodiments, a gas collccling device is set in the aération section to collcct an aération gas. The gas collccling device is fluidly connected with Lhe gas inlet of the guiding tube of the concentrated mixed liquor driving device. In some embodiments, the gas collecting device comprises a gas collccling hood, optîonally above an aération device, and a gas guiding pipe can be set on top of the gas collecting hood to introduce tlie gas collected by lhe gas collecting hood to lhe guiding tube via lhe gas inlet of the guiding tube. In some embodiments, a flow control valve is set on lhe gas guiding pipe to control lhe flow of gas entering lhe guiding tube so as to further control the flow of lhe concentrated mixed liquor. In some cases, an atmospherîc vent is set on the gas collecting hood to discharge al least part of lhe gas collected by the gas collecting hood, and a flow control valve can be set on the atmospherîc vent to conirol the flow or proportion of lhe discharged gas so as to further control the flow of gas entering the guiding tube and control lhe flow of the concentrated mixed liquor.

In some embodiments, lhe gas collecting hood can be set at middle part or upper part or top of the aération section. In some cases, a part of the gas collecting hood can extend upward and protrude out of the top wall of the aération section to form a gas collccling pocket, and at least part of the wall of the gas-collecting hood is defined by the wall of the aération section. In some cases, lhe gas collecting hood can be an independent umbrclla-type hood in lhe aération section. In some other cases, lhe gas collecting hood is defined by the top wall or roof of the aération section and optîonally by side wall connecting with lhe top or roof of lhe aération section.

In some embodiments of the apparatus for biological sewage treatment of the

I3 présent invention, the anaérobie treatment section, the sédimentation section and the aération section can be disposed in one horizontal barrel. The barrel can be a cylindrical or polygonal barrel, preferably a tctragonal, pentagonal, hexagonal, heptagonal, octagonal barrel or even a more polygonal barrel.

In some embodiments of the apparatus for biological sewage treatment according to tlie présent invention, a device for supplying lire gas, such as an air blower for supplying aération gas, and/or a device for supplying sewage feed, such as sewage feed pump or vacuum sewage drawing device (including vacuum pump) can be intemally set in the apparatus for biological sewage treatment, for example, in the anaérobie treatment section, sédimentation section and/or aération section, preferably in the aération section. The advantages of such arrangement at least include reducing noise, facilitating arrangement and installation, and deployment in an area such as a residential area with large population and small space.

In some embodiments of the apparatus for biological sewage treatment according to the présent invention, al least part of tlie apparatus for biological sewage treatment is set below the ground. For example, at least part of or even the whole of the apparatus for biological sewage treatment according to tlie présent invention can be set below the ground, for example, set in a semi-basement or a basement, to save land occupation, reducc noise and avoid influence on landscapc. In some cases, tlie apparatus for biological sewage treatment can be set on tlie ground. When the apparatus for biological sewage treatment according lo the présent invention is set on the ground or in a semi-basement, it can be set outdoors or in a building. In some other cases, tlie apparatus for biological sewage treatment according to the présent invention can be set on a movablc platform, for example on a vehicle such as a traiter or truck, so that it can be readily and flexibly transported to different sites, and quickly deployed and installed to provide instant service.

The apparatus and method for biological sewage treatment according to the présent invention sufficiently uses an aération gas in biological sewage treatment, so that a sludge return pump is not used, energy consumption and equipment investment arc reduced, apparatus disposai and process layout are flexible, movable parts and connecting pipes arc reduced, and reliability is improved.

In tlie apparatus and method for biological sewage treatment according lo the

I4 présent invention, the concentrated mixed liquor contacts with an oxygcn-containing aération gas such as an aération gas so as to enhance effects of removing nitrogen and COD and improve sewage treatment effects. Hencc, the apparatus and method for biological sewage treatment according to the présent invention had advantages of good quality of water outflow, high volumétrie loading, less occupation of land, and less influences on ncighboring environment.

According to the présent invention, the apparatus for biological sewage treatment can be a tower type apparatus for biological sewage treatment, comprising a sédimentation chamber and a pncumatic mixed liquor elevating device using a gas to elevate a concentrated mixed liquor of the sédimentation chamber, in which the pncumatic mixed liquor elevating device is used as a concentrated mixed liquor driving device, and elevating a concentrated mixed liquor pertains to driving a concentrated mixed liquor to flow.

In some embodiments of the présent invention, the sédimentation chamber can be a sédimentation device capable of separating an aerated mixed liquor to form a supematant and a concentrated mixed liquor. In general, the sédimentation chamber is a sédimentation tank or sédimentation basin or sédimentation section, in which tilted plates or tilted pipes could be set to enhance séparation effects. The concentrated mixed liquor usually is formed in the lower part of die sédimentation device under sédimentation effects, in which sludge collecting channels could be set to enhance the sédimentation of the concentrated mixed liquor. In some cases, an overflow well is set in upper part of the sédimentation device to discharge the supematant as water outflow.

In some embodiments of the présent invention, the pneumalic mixed liquor elevating device of the tower type apparatus for biological sewage treatment is any suitable device capable of elevating a concentrated mixed liquor by using a gas, preferably a pneumalic mixed liquor elevating device allowing contact between the gas and the mixed liquor, for cxample, a pneumalic pump or a pncumatic mixed liquor elevating tube. In some cases, the pncumatic mixed liquor elevating device comprises a substanlively vertical liquor elevating tube for drawing the concentrated mixed liquor, and a gas guiding pipe which is connected with the liquor elevating tube and used for introducing the gas to the liquor elevating tube.

In some embodiment of lhe présent invention, the liquor elevating tube has an liquor inlet for drawing the concentrated mixed liquor and an outlet for discharging a gas-liquor mixture of the gas and the concentrated mixed liquor, and the gas guiding pipe is connected with a middle part or lower part of the liquor elevating tube. When 5 lhe gas enters lhe liquor elevating tube via the gas guiding pipe, the gas is mixed with the concentrated mixed liquor to form a gas-liquor mixture, and the gas-liquor mixture in lhe liquor elevating tube flows upward under the action of pressure and floaling cffccts of the gas, and then is dischargcd from die outlet at the top of the liquor elevating tube, so that die concentrated mixed liquor is pneumatically elevated by I0 using the gas. In some cases, sludge circulation in die whole apparatus for biological sewage treatment is rulfilled by elevating lhe concentrated mixed liquor with the gas.

In some embodiments, the gas guiding pipe is fluidly connected with a suitable gas source, and a Ilow control valve is used to control the gas flow entering the gas guiding pipe so as to control lhe flow of lhe conccniratcd mixed liquor lo be elevated.

In some other embodiments, a flow control valve is set at upstream of the inlet of lhe liquor elevating tube to control the flow of lhe concentrated mixed liquor that enters the liquor elevating tube.

In some embodiments, die gas can be derived from any suitable gas sources, for example, the gas can be from an air compressor, an air blower, a storage tank of gas 20 such as air, oxygen, nitrogen and inert gas. Preferably, the gas has a pressure greater than or equal lo atmosphère pressure. Preferably, the gas is an oxygen-containing gas. In some cases, at least part of the gas is from an aération gas. The aération gas can bc collcctcd from any place of an aération device. Preferably, the aération gas is an aération gas released from an aerated mixed liquor and collected from an upper part of 25 an aération device. In some cases, an additional sludge retum pump is used to elevate the concentrated mixed liquor in the sédimentation chamber. In some other cases, lhe additional sludge retum pump is driven by using the gas.

In some embodiments of the présent invention, a sludge collecting channel is set at the botlom of the sédimentation chamber, and lhe liquor inlet of the liquor elevating 30 tube protrudes into the sludge collecting channel. In some embodiments, one or more pncumatic mixed liquor elevating devices are sel in the sédimentation chamber. In sotnc cases, a plurality of pneumatic mixed liquor elevating devices can protrude into

I6 one or more sludgc collecting channels. Using a plurality of pneumatic mixed liquor elevating device can enhance transportation ability of the concentrated mixed liquor, and improve die contact between the gas and tlie concentrated mixed liquor.

In some embodiments of the présent invention, the tower-type apparatus for biological sewage treatment further comprises a gas-liquor separating tank to separate the concentrated mixed liquor and the gas from tlie pneumatic mixed liquor elevating device, and the gas-liquor separating tank can be fluidly connected with the outlet of the liquor elevating tube.

In some embodiments of tlie présent invention, the tower-type apparatus for biological sewage treatment further comprises an aération chamber, and the aération chamber has a gas collecting hood for collecting an aération gus in the aération chamber. In some embodiments of the présent invention, the aération chamber can be a device capable of performing aération treatment of the mixed liquor, for example, an aération tank or aération basin or aération section. An aerator can be set in the aération chamber lo enhance aération treatment. The aerator can be one or more of spiral aerator, micropore aerator, plate-type aerator, rotation mixing aerator, tube aerator, or jet aerator.

In some cases, al least part, preferably ail, of the aération gas in the aération chamber is collectcd and introduced lo the concentrated mixed liquor elevating device. In some cases, a gas-liquor separating device is set in lhe acralion chamber to separate aération gas and die aerated mixed liquor so that the aerated mixed liquor enters the sédimentation chamber and the aération gas does not enter the sédimentation chamber. The gas-liquor separating device can be one or more containers or one or more tubes, which top has one or more openings to allow the aerated mixed liquor lo enter tlie containers or tubes, and which bottom has one or more pipes fluidly connected with the sédimentation chamber lo allow the aerated mixed liquor in the containers or tubes to enter lhe sédimentation chamber. In some cases, tlie openings of the containers or tubes are immerged into lhe aerated mixed liquor of tlie aération chamber to reçoive Lhe aerated mixed liquor and prevent the aération gas from entering tlie sédimentation chamber.

In some embodiments, a gas collecting device is set in the aération chamber to collecl an aération gas. The gas guiding pipe is connected with tlie gas collecting

I7 device, The gas collecting device can comprise a gas collecting liood optionally disposed above an aération device. According to some embodiments of the présent invention, lhe gas collecting liood is fluidly connected with the gas guiding pipe. For cxample, the gas guiding pipe is sel on the top of die gas collecting hood to allow the gas collccted by lhe gas collecting hood to enter the inixed liquor elevating device. In some embodiments, a flow control value is sel on the gas guiding pipe to control the flow of gas entering the liquor elevating tube so as to control the flow of the concentrated mixed liquor. In some cases, the gas collecting hood further has an atmosphcric vent to discharge at least part of the gas collected by the gas collecting hood, A control valve can bc set on the atmosphcric vent to control the flow or proportion of the gas to bc dischargcd.

In some embodiments, die gas collecting hood is set in a middle part or upper part of the aération chamber. In some cases, a part of the gas collecting hood can extend upward and protrude out of lhe top wall of the aération section to form a gas collecting pocket, and at least part of the wall of the gus-collecting hood is defined by tlic wall of the aération section. In some cases, the gas collecting hood can be an independent umbrella-type hood in the aération section. In some other cases, the gas collecting hood is defined by the top wall of Lhe aération section and optionally by side wall connecting with the top wall of the aération section.

In some embodiments of lhe présent invention, the aération chamber further has a liquor collecting tank to collect a mixed liquor in the aération chamber, Lhe liquor collecting tank is fluidly connected with the sédimentation chamber, and at least part of the concentrated mixed liquor is derived from lhe mixed in the liquor collecting tank.

In some embodiments of tlic présent invention, the tower type apparatus for biologicul sewage treatment further comprises a division plate between the aération chamber and the sédimentation chamber. The division plate can be a fiat plate, a cône type plate, an inverted cône type plate, a foldcd plate or any suitable sketch plate. The cône type plate or the inverted cône type plate may hâve an apex angle of about 60° to about 179°, for example, about 70° to about 150°, about 80° to about 120°, about 85° to about 105°, or about 90°. A rclatively small apex angle can incrcase lhe height of the sédimentation chamber, which facilitâtes séparation of the mixed liquor to form a supernatant and a concentrated mixed liquor; while a relativcly large apex angle can facilitate the arrangement and installation of devices in the aération chamber and the sédimentation chamber. In some cases, the apex angle is about 69°, about 70°, about

80°, about 100°, about 120°.

In some embodiments of the lower type apparatus for biological sewage treatment of the présent invention, the gas collecting hood is one or more gas collccting hoods formed by one or more upward protruding parts of the division plaie. In some embodiments, the gas collccting hood is one or more gas collecting hoods formed by onc or more upward protruding parts located at a margin of the division 10 plate, or formed by a circular groove consisting of a marginal part of the inverted cône type division plate and an internai wall of the aération chamber.

According to some embodiments of the tower type apparatus of the présent invention, the liquor collecting tank is located in the middle part of tlie division plate. In some cases, lhe liquor collecting tank has upward openings and has a gap between 15 the liquor collecting tank and the lower surface of the division plate to allow the mixed liquor enter the liquor collccting tank and to prevent the aération gas from entering the liquor collecting tank. This arrangement facilitâtes lhe séparation between the aération gas and the mixed liquor.

According to some embodiments of the lower type apparatus for biological 20 sewage treatment of the présent invention, die liquor collecting tank has a top defined by a part of the division plate, and this part of the division has one or more through holes or pipes to allow the mixed liquor in the liquor collecting tank to enter the sédimentation chamber. In some cases, the through holes or pipes are disposed to prevent the aération gas from entering lhe sédimentation chamber via the through 25 holes or pipes. For examplc, the through holes can be sheltered by the liquor collecting tank to prevent the aération gas entering the sédimentation chamber via lhe through holes.

According to some embodiments of lhe lower type apparatus for biological sewage treatment of tlie présent invention, the middle part of the division plate 30 protrudes downward to form a recess part as a sludge collecting tank at the bottom of the sédimentation chamber. Thus, tlie concentrated mixed liquor in lhe sédimentation chamber enters the sludge collecling tank under action of gravily. Preferably, the inlet of the liquor clevating tube protrudes into the sludge collecting tank.

According to sornc embodiments of the tower type apparatus for biological sewage treatment of the présent invention, a mixed liquor dîslributor is set in the lower part of the sédimentation chamber to distribute uniformly the mixed liquor from lhe liquor collecting tank in the lower part of the sédimentation chamber. In some embodiments, the mixed liquor distributor is a substantively horizontal annular tube having a plurality of downward openings, or a substantively horizontal overtumed annular groove as defined by the outer wall of the gas-liquor separating tank and a skirt which is joined to the outer wall of the gas-liquor separating tank and protrudes obliquely downward inside the lower part of the sédimentation chamber. The mixed liquor distributor can uniformly distribute the mixed liquor from the liquor collecting tank in the sédimentation chamber, and substantively do not disturb the séparation of the mixed liquor to form llie supematant and lhe concentrated mixed liquor.

According to some embodiments of the tower type apparatus for biological sewage treatment of die présent invention, the gas-liquor separating tank is an annular tank between the liquor clevating tube and a concentric exlemal sleeve. The lower part of the gas-liquor separating tank is fluidly connected with the lower part of the aération tank so that tire concentrated mixed liquor in the gas-liquor separating tank retums to the lower part of lhe aération tank. In some other embodiments, lhe gas-liquor separating tank is an independent tank or tube, which upper part is fluidly connected with the outlet of the liquor elevaling tube to reçoive the concentrated mixed liquor and lhe gas from tlie liquor clevating tube, and which lower part is fluidly connected wiüi the lower part of the aération chamber so that the concentrated mixed liquor in lhe gas-liquor separating tank can retum the lower part of the aération chamber.

According to some embodiments of lhe tower type apparatus for biological sewage treatment of the présent invention, a first concentrated mixed liquor retum pipe is set between lhe gas-liquor separating tank and lhe aération chamber, so that the concentrated mixed liquor from lhe gas-liquor separating tank can retum the aération chamber via the first concentrated mixed liquor retum pipe.

According to some embodiments of the tower type apparatus for biological sewage treatment of the présent invention, an anaérobie reaction chamber or

anacrobic treatment section is sel below llie aération chamber.

In llie présent invention, the anacrobic reaction chamber or anaérobie treatment section can be any device capable of performing anacrobic treatment of a mixed liquor formed with the concentrated mixed liquor and a sewage feed. In some other 5 embodiments, the anacrobic réaction chamber is any device capable of performing anaérobie treatment of a sewage feed. In some cases, the anaérobie treatment is performed by allowing the mixed liquor lo flow slowly under a state with a dissolving oxygen level of not grcater than O.lmg/L, for example a state without aération. A suitable anaérobie treatment chamber or section can be a tank or basin in which llie 10 mixed liquor can flow in laminar, vertical or radial manner. For examplc, llie anaérobie reaction chamber can be an upflow anaérobie sludge blanket (UASB) reactor, comprising u inixing zone at the bottom thereof, a gas collccting zone for collecting methane bubbles at top thereof, and an anacrobic reaction zone between the mixing zone and the gas collccting zone,

I5 According to some embodiments of the tower type apparatus for biological sewage treatment of thc présent invention, a second concentrated mixed liquor return pipe is set in thc lower part (preferably the sludge collecting tank) of the sédimentation chamber to discharge at least part of üic concentrated mixed liquor out of the sédimentation chamber and the aération chamber. In some cases, a pump is 20 used lo dîscliarge compulsively a part of llie concentrated mixed liquor. In some cases, thc dischargcd concentrated mixed liquor is introduccd into the anaérobie réaction chamber below the aération chamber, preferably into the lower part of thc anaérobie reaction chamber. When the interface between llie supematant and thc concentrated mixed liquor in the sédimentation chamber is at a relalively high position or sludge 25 floating is about to occur or occurs already in the sédimentation chamber, a part or the whole of the concentrated mixed liquor is dischargcd via the second concentrated mixed liquor return pipe and/or the first concentrated mixed liquor return pipe so as to lower the interface quickly and effectively and to avoid or eliminate sludge lump formation and sludge floating.

According to some embodiments of the tower type apparatus for biological sewage treatment of thc présent invention, a sludge lump breaking device is sel in the sédimentation chamber. During a long-lerm run of the apparatus for biological sewage

treatment, an amount of sludge may keep in suspension state without sellling to the lower part of the sédimentation chamber and agglomerate to form a sludge lump that is prone to floating upward under anaérobie environment of tire sédimentation chamber and discharging along with the water outflow to compromise water quality.

The sludge lump may be broken by performing intermittent aération treatment so as to improve sludge settling property and to avoid compromising water quality. The sludge lump breaking device is any suitable device capable of breaking a sludge lump into pièces such as sludge particles which are easy of sédimentation. In some cases, the sludge lump breaking device is a device using mechanical force to break sludge lump, I0 for cxample, is a pneumatic sludge lump breaking device, such as any suitable acrator, or a gas distributor, such as a gas distributor tube with upward openings. In some cases, lire sludge lump breaking device is actively joincd to the sédimentation chamber, which can enter or leave or stay al any desired position in the sédimentation chamber.

I5 According to some embodiments of the présent invention, the apparatus for biological sewage treatment further comprises a power room and a heat exchanger, in which the heat exchanger uses a heat released from a power device or equipment in the power room to heat the mixed liquor in the apparatus for biological sewage treatment. The power room and the heat exchanger are preferably sel in the aération 20 chamber or section and/or lhe anaérobie réaction chamber or section and/or the sédimentation chamber or section, in which the heat exchanger uses a heat released from a power device in lhe power room to heat the mixed liquor. The beat exchanger can be any suitable heat exchanger, especially a beat exchanger capable of exchanging heat between a gas and the mixed liquid, for example, the heat exchanger can be 25 selected from spiral tube heat exchangers, straight tube heat exchangcrs or combinations thereof. The power device can be any power device used in the apparatus for biological sewage treatment, such as air blower, a sewage feed pump or a vacuum pump of vacuum water drawing device as well as relevant control or monitoring devices and instruments.

In somc embodiments, lhe gas heated in the power room enters in a heat exchanging tube of the heat exchanger to perform beat exchange with a mixed liquor cxtemally flowing through lhe heat exchanging tube. In some other embodiments, the gas enters a jacket of the heat exchanger to perform heat exchange with a mixed

liquor flowing Üirough the heat exchanging tube. In some cases, the beat exchanger has one or more beat exchanging tubes.

In some embodiments, a gas distributor is set in the power room to control the distribution of gas in the power room. In some cases, the gas distributor is a cover 5 plate with one or more air outlets at edge of the cover plate, in which at least one of the air outlets is oriented loward a power device in the power room. In some cases, the gas distributor can bc a grille with tilted baffles to guide air toward a power device in the power room.

In some embodiments, the power device can bc any suitable power device useful 10 in biological sewage treatment, such as pumps and/or air blowers, particularly sludge feed pump, mixed liquor circulating pump, aération air blower, etc.

In some embodiments, an air inlet is set at the bottom of the power room and an air outlet is set al the top of the power room so that lhe air passes the power room and the heat exchanger in a natural conveclive manner.

In some embodiments, a forced air supplying device is set in lhe power room and/or tlie heat exchanger so as to force lhe air pass through the power room and tlie heat exchanger. For example, the forced air supplying device is an air blower, such as axial flow venlilator.

In some embodiments, the gas inlet of the power room is sel at lhe lowest place of lhe power room so lhat a liquid deposited in the power room may be drained via tlie air inlet. In some cases, the liquid deposited in lhe power room may be an effusion from a wall between the power room and lhe anaérobie reaction chamber or a wall between the power room and the aération chamber, or from a power device or connecting pipes thereof in the power room, or from pipelines or valves. The air inlet as set al lhe lowest place of the power room can discharge said effusion in time so as to prevent the devices in the power room from water logging.

In some embodiments, instruments, switches and/or valves for monitoring and/or controlling the apparatus can bc further sel in the power room.

Hence, the apparatus for biological sewage treatment of the présent invention has 30 a compact structure, can effectivcly remove heat rcleased from power devices, and uses lhe released heat to elevate température of a mixed liquor, so that technical

effects such as high réaction efficiency, improved treatment cffccts, energy saving and noise réduction arc achievcd.

The apparatus for biological sewage treatment of the présent invention can be arranged in vertical type or horizontal type, which is suitable for placing in a building 5 or embedding under the ground, or selting on a movable platform. In addition, the apparatus for biological sewage treatment of lhe présent invention is particularly suitable for miniaturization and communitization of sewage treatment.

In some embodiments of the apparatus for biological sewage trealment of the présent invention, tlic sédimentation chamber and the aération chamber and/or the 10 anaérobie réaction chamber can be set in a tower type barrel. The barrel can be a cylindrical or polygonal barrel, preferably letragonal, pentagonal, hexagonal, heptagonal, oclagonal barrel or even a more polygonal barrel.

In the context, “downward refers to a direction substantivcly identical lo the gravity direction, comprising but not being limited to a direction coïncident with the 15 gravity direction; and “upward refers to a direction substantively against the gravity direction, comprising but not being limited to a direction coïncident with the reverse direction of gravity.

In the context, “substantive” or substantively means when a term is modified by it, the tenu can change within a suitable range around lhe central value of the term, 20 for cxamplc, the range can be defîned by, for example, ±20%, ±15%, ±10%, ±5%, ±2%, or ±1% of the central value.

Another aspect of the présent invention provides a method for biological sewage treatment, comprising using a gas to elevule a concentrated mixed liquor in a sédimentation chamber. In some embodiments, at least a part of the gas is derived 25 from an aération gas.

In some embodiments, the method for biological sewage treatment of lhe présent invention further comprises the following steps: separately collecting a mixed liquor and an aération gas from an aération chamber, performing sédimentation trealment of the mixed liquor in lhe sédimentation chamber to obtain a supematant and lhe 30 concentrated mixed liquor, and elevating llie concentrated mixed liquor in a pneumatic mixed liquor elevating device by using the aération gas collected from the

aération chamber.

The method for biological sewage treatment of lhe présent invention further comprises separating in a gas-liquor separating tank the aération gas and Lhe concentrated mixed liquor froin lhe pneumatic mixed liquor elevating device, and 5 introducing al least part of the separaled concentrated mixed liquor into the aération chamber.

The method for biological sewage treatment of the présent invention further comprises performing aération treatment of the supematant in the sédimentation chamber periodically or when a sludge lump appears or is about to appear in the I0 supematant in the sédimentation chamber. The lime or duration time for performing the aération treatment of the supematant can be determined according Lo Lhe situations of sludge lump formation or breaking or floating, as long as the sludge lump is eliminated and sludge lump floating is avoided. Generally, when lhe aération treatment of toc supematant is performed, the sewage feed should stop so that sludge 15 does not enter the water outflow.

The method for biological sewage treatment of the présent invention further comprises discharging at least a part of toc concentrated mixed liquor of the sédimentation chamber to un anaérobie reaction chamber. The concentrated mixed liquor can be discharged before or after being clevated by the gas. The step of 20 introducing the parL of the concentrated mixed liquor to the anaérobie reaction chamber can bc performed intermiltcntly or continuously. The time and duration time of the step can bc determined according to toc position of interface between the supematant and lhe concentrated mixed liquor and/or lhe situation of sludge floating, as long as üie interface is controlled at a desired position so that sludge does not enter 25 toc water outflow. For example, when the interface is al a relatively high position, a part of lhe concentrated mixed liquor can be introduced to lhe anaérobie réaction chamber to lower lhe interface position so as to ensure water quality of the water outflow; when sludge floating occurs or is about lo occur, a part or even whole of the concentrated mixed liquor in toc sédimentation chamber as well as a part or even 30 whole of toc supematant can be discharged, preferably introduced to the anaérobie réaction chamber, so as lo lower the interface or avoid or eliminate sludge floating.

Without being limited to any theory, the inventors believe the main reasons for sludge floating in lhe sédimentation chamber are as follows: anaérobie décomposition occurs under anaérobie condition and generales médiane gas and carbon dioxide gas, and then sludge absorbs gas and floals upward. Hence, periodically pcrfomüng aération treatment in intermittent mode can inhibit anaérobie décomposition, break 5 sludge lump, improve sédimentation property of sludge, and effectively avoid occurrence of sludge floating. In addition, a relatively large retum flow of lhe concentrated mixed liquor is achievcd by passing an aération gas through the pneumatic mixed liquor clevaling device, so thaï the rétention time of sludge in lhe sédimentation chamber is sliortcned, and lhe sludge floating caused by anaérobie 10 décomposition under anaérobie condition is avoided as well.

In lhe apparatus and method for biological sewage trealmcnl of lhe présent invention, the aération gas and the mixed liquor in the aération chamber is separated and then introduced to the sédimentation chamber, lhe aération gas mcrely passes through tlie pneumatic mixed liquor clevaling device to elevatc the concentrated 15 mixed liquor in the lower part of the sédimentation chamber, so that the process of separating the mixed liquor into the supematant and the concentrated mixed liquor in lhe sédimentation chamber is not dislurbed by lhe aération gas. In the mcanlime, lhe concentrated mixed liquor in the lower part of lhe sédimentation chamber is continuously drown in a relatively gréai retum flow by using the collected aération 20 gas, which facilitâtes lowering the position of the interface between the supematant and the concentrated mixed liquor in lhe sédimentation chamber, reducing the rétention time of sludge in die sédimentation chamber, and avoiding or eliminating sludge floating.

In addition, the concentrated mixed liquor elevated by the pneumatic mixed liquor clevaling device passes the gas-liquor separating tank and directly relums to the aération chamber, rather than tlie sédimentation chamber, so that the process of separating lhe mixed liquor into lhe supematant and the concentrated mixed liquor in the sédimentation chamber is not dislurbed.

Furthermore, the aération device as sel in die sédimentation chamber can periodically acrate lhe supematant in the sédimentation chamber, or acratc lhe supematant when sludge lump forms or is about to form and/or sludge floating occurs or is about to occur in the supematant. Thus, the dissolved oxygen concentration around Lhe sludge lump increases, lhe sctlling property of sludge is improved, the formation of sludge lump is inhibited, the formed sludge lump is broken, so thaï the sludge floating is avoided, Üic separating effects of the sédimentation chamber is improved, and the sédimentation can work stably for a long-term.

Moreover, at least a part of lhe concentrated mixed liquor in lhe sédimentation chamber is introduced to lhe anaérobie reaction chamber, so that the interface between the supernatant and lhe concentrated mixed liquor in the sédimentation chamber can be readily controlled at a desired position, the water quality of water outflow is assured, and sludge floating can be avoided or eliminated in lime.

Further, the inventors of the présent invention uncxpectedly fine! when the aération gas is used to elevate the concentrated mixed liquor, the effects of removing nitrogen and/or removing COD is improved surprisingly. Without being rcstricted to any theory, the inventors believe that lhe contact between lhe concentrated mixed liquor from the sédimentation chamber and the oxygcn-conlaining gas (preferably aération gas) increases lhe dissolved oxygen concentration, so that the dénitrification ability of sludge is improved, and better effects of removing nitrogen and removing COD are achieved.

In the présent invention, the aération gas is used to perform sludge retum, so that a sludge retum pump is not used, energy consumplion and equipment investmenl are reduced, and apparatus disposai and process layoul arc flexible. In addition, when movable parts and connecting pipes arc reduced, reliabilily of the apparatus is improved as well. Further, lhe apparatus for biological sewage treatment of the présent invention has a compact structure, and the volume and floor space of lhe whole apparatus are reduced.

The apparatus for biological sewage treatment apparatus has a small floor area, can run for a long-term in stable and reliablc manner, needs subslantively no maintenance, is suitable for placing in a building or embedding under lhe ground or setting on a rcmovable platform, and is particularly suitable for in-sile or on-the-spot sewage treatment, for example sewage treatment in a community or island.

Bricf Description of the Drawings

Fig. I is a structural diagram of one embodiment of tlie apparatus for biological sewage trcaimeni of die présent invention.

Fig. 2 is a structural diagram of another embodiment of tlie apparatus for biological sewage treatment of the présent invention.

Fig. 3 is a structural diagram of onc embodiment of power room and heat exchanger of the apparatus for biological sewage treatment of lhe présent invention.

Fig. 4 is a structural diagram of another embodiment of power room and heat exchanger of tlie apparatus for biological sewage treatment of the présent invention.

Fig. 5 is a structural diagram of further another embodiment of power room and heat exchanger of lhe apparatus for biological sewage treatment of tlie présent invention.

Fig. 6 is a structural diagram of further another embodiment of tlie apparatus for biological sewage treatment of lhe présent invention.

Spécifie Models for Carrying Out the Invention

Some embodiments of the présent invention are further illustrated in conjunction with the drawings, but il is not intended to rcstrict tlie protection scope of the présent invention.

Example l

Fig. I is a structural diagram of an embodiment of the apparatus for biological sewage treatment of the présent invention, in which the apparatus for biological sewage treatment comprises an anaérobie treatment section (SI), a sédimentation section (S2) and an aération section (S3), which are set in a barrel and separated between each other by division plates.

A sewage feed as water inflow was introduccd to the anaérobie treatment section (SI) via a sewage feed supplying device (a sewage pump or a water drawing device, not shown). The sewage feed was mixed in the anaérobie treatment section (SI) with a concentrated mixed liquor from a concentrated mixed liquor driving device (which included a concentrated mixed liquor pipe (103), a guiding tube (109), a gas-liquor mixture pipe (110) and a gas-liquor separator (111)), and passed lhe anaérobie treatment section (SI ) slowly to obtain an anaérobie treatment mixed liquor.

The anaérobie treatment mixed liquor from Lhe anaérobie treatment section (SI) was inlroduced to the aération section (S3) via an anaérobie treatment mixed liquor pipe (101), and contactcd with an aération gas from an aerator (104) to perform aération treatment so as to obtain an aération treatment mixed liquor. The aération gas floated upward in the aération section (S3) and cscapcd from surface of the aération 10 treatment mixed liquor and accumulated in the upper part of the aération section (S3).

The aération treatment mixed liquor passed through a gas-liquor separating device (106) and an aération treatment mixed liquor pipe (105) and then entered the sédimentation section (S2), in which the gas-liquor separating device (106) had a upward opening to allow lhe aération treatment mixed liquor enter the gas-liquor 15 separating device (106), and lhe opening was located under the surface of Lhe mixed liquor to avoid the aération gas entering lhe sédimentation section (S2).

The aération treatment mixed liquor from the aération section (S3) was uniformly distributed in the sédimentation section (S2) via a mixed liquor distributor (102), and separated into a supematant in the upper part of the sédimentation section 20 (S2) and a concentrated mixed liquor in the lower part of the sédimentation section (S2). The supematant as a water outflow was dischargcd from an overflow well (112). The concentrated mixed liquor in lhe lower part of the sédimentation section (S2) retumed to the anaérobie treatment section (SI) via a concentrated mixed liquor driving device (which included a concentrated mixed liquor pipe (103), a guiding tube 25 ( 109), a gas-liquor mixture pipe (110) and a gas-liquor separator (111)).

The aération gas accumulated in the upper part of the aération section (S3) entered into lhe guiding tube (109) via a gas collecting hood (107) and a gas guiding pipe (108). The redundant part of the aération gas in the gas collecting hood (107) could be vented from vent valve (113). The aération gas conlacled in lhe guiding tube 30 (109) with the concentrated mixed liquor from the sédimentation section (S2) and was mixed to form a gas-liquor mixture. The gas-liquor mixture moved upward in lhe guiding tube (109) under the pressure and floating effects of the aération gas, and entcred in the gas-liquor separating device (l 11) via the gas-liquor mixture pipe (110).

The gas-liquor mixture was separated into the concentrated mixed liquor and llie aération gas in the gas-liquor separating device (111), in which the aération gas was discharged, and the concentrated mixed liquor was introduced into the anaérobie treatment section (S 1 ),

In the apparatus for biological sewage treatment of Fig.l, the aération gas was used to drive the concentrated mixed liquor (i.e., sludge) to flow, and thus the concentrated mixed liquor was driven to circulate in the wholc apparatus for biological sewage treatment, so that the energy of the gas was suffïcicntly utilized, in 10 which the flow rate of the sludge retum could be regulated and controlled by controlling the flow rate of the aération gas entering the gas guiding pipe (108) via the vent valve (113). Hence, the energy consumplion of the whole apparatus for biological sewage treatment was reduced. In addition, when no sludge relum pump was used, the equipment investment was reduced, while the reliability of the 15 apparatus for biological sewage treatment was improved.

In addition, the apparatus for biological sewage treatment of Fig.l could be arranged in horizontal type, so that the height of whole apparatus was reduced. In the meantime, the anaérobie treatment section (SI), the sédimentation section (S2) and the aération section (S3) were integrated together compaclly, so that the floor area was 20 reduced, the structure was simplificd, and die maintenance was convenicnt. Hence, the apparatus for biological sewage treatment could be placed underground or semi-underground structure, or installcd on a movable platform (for example, on a vehicle) if required, the floor area was reduced, température was kept, environment was beautified, and transportation and deployment were convenienl.

In the apparatus for biological sewage treatment of Fig.l, the aération gas conlacled with the concentrated mixed liquor (i.e., active sludge) to oxygenalc the sludge during élévation, the oxygenated sludge was then mixed with the sewage feed during anaérobie treatment, so that the dénitrification in the anaérobie treatment section (SI) was enhaneed, the effects of removing nitrogen and removing COD were improved, the cfïîciency of sewage treatment increased, and the water quality of the water outflow was improved.

Example 2

Fig.2 is a structural diagram of an embodiment of the tower type apparatus for biological sewage treatment of the présent invention, in which the tower type 5 apparatus for biological sewage treatment included an anaérobie reaction chamber (201), an aération chamber (225) as disposcd above the anaérobie reaction chamber (201), a sédimentation chamber (221) as disposed above the aération chamber (225), and a division plate (212) between lhe aération chamber (225) and the sédimentation chamber (221). A gas collecting hood (211) was set in the aération chamber (225) to 10 collect aération gas, and a Iiquor collecting tank (209) was sel in lhe aération chamber (225) to collect the mixed Iiquor in the aération chamber (225). A pneumatic mixed Iiquor elevating device comprising a Iiquor elevating tube (216) and a gas-liquor separating tank (215) was set in the sédimentation chamber (221). Ail these components were arranged in a single cylindrical tower (or polygonal tower) having a 15 height of about 10 m to about 30 m.

A sewage feed from a sewage feed pipe (206) entered the anaérobie reaction chamber (201) via a sewage feed valve (205), a pump (204) and a pipe (203). The sewage feed formed a laminar upflow in the anaérobie reaction chamber (201) so that the sludge in the anaérobie réaction chamber (201) stably suspendcd under balance of 20 flowing and settling to form a sludge bed, and thus lhe anaérobie reaction chamber (201) became an upflow sludge bed reactor. A clear Iiquor penetrated the sludge bed and continuously flowed upward and passcd through an opening (202) (preferably equipped with an unidirectional passing device, such as an one-way valve) on a division plate (227). Optionally, a gas collecting device (such as a gas collecting hood 25 as described in US 6,063,273, not shown) could be set below the division plate (227) to collect a gas such as methane as generated by lhe sludge bed.

The clear Iiquor from the anaérobie reaction chamber (201) was mixed with an aération treatment mixed Iiquor in tlic aération chamber (225). An aération gas entered lhe aération chamber (225) via a gas inlet pipe (226) and aerated the mixed Iiquor in 30 the aération chamber (225). An aerator (not shown) could be set in the aération chamber (225). After aération treatment, lhe aération gas was accumulated in an annular type gas-collecting hood (211) in the upper part of the aération chamber (225), while the aération treatment mixed liquor entered a liquor collecting tank (209), so that lhe aération gas and lhe aération treatment mixed liquor was separated.

The mixed liquor in the liquor collecting tank (209) entered the lower part of lhe .sédimentation chamber (221) via a through hole or pipe (210), and was separated in lhe sédimentation chamber (221) to form a supernatant in the upper part thereof and a concentrated mixed liquor in lhe lower part thereof. The supernatant as water outflow (217) was dischargcd from an overflow well (218). The concentrated mixed liquor declincd and entered a sludge collecting tank (224), and then entered an liquor elevating tube (216) via a lower inlet of the liquor elevating tube (216). The aération gas in the gas collecting hood (211) entered lhe liquor elevating tube (216) via a gas guiding pipe (222), so that lhe concentrated mixed liquor from dre sludge collecting tank (224) was drawn and elevated in the liquor elevating tube by lhe aération gas from the gas collecting hood (211) in the liquor elevating tube (216). Tire aération gas together with lhe concentrated mixed liquor in lhe liquor elevating tube (216) then flowcd upward and entered a gas-liquor separating tank (215) to perform gas-liquor séparation, the separated gas was dischargcd and the separated concentrated mixed liquor stayed in tire gas-liquor separating tank (215). At least a part of the concentrated mixed liquor in lhe gas-liquor separating tank (215) retumed to tire lower part of the aération chamber (225) via a first concentrated mixed liquor relum pipe (223).

When the sludge-water interface in the sédimentation chamber (221) was at a relatively high position so that the water quality of water outflow (217) was influenced by sludge, al least a part of the concentrated mixed liquor in lhe sludge collecting tank (224) could be dischargcd via a second concentrated mixed liquor retum pipe (208), a valve (207) and the pump (204) and entered lhe anaérobie reaction chamber (201). Titus, the sludge-water interface in lhe sédimentation chamber (221) could drop and be effectively controllcd and regulated by using lhe valve (207) and the pump (204) to ensure the water quality.

When sludge lump or sludge floating occurred or was about to occur in the sédimentation chamber (221), an aération gas could enter lhe middle part of upper part of the sédimentation chamber (221) via gas inlet pipes (219 and 214) and gas distributing tubes (220 and 213), which was used as a sludge lump breaking device, so

as to stir Lhe supematant and/or the concentrated mixed liquor in the sédimentation chamber (221) to break sludge lump or eliminate sludge floating. The aération gas from the gas inlet pipes (219 and 214) entered die sédimentation chamber (221) pcriodically or intermittent!y, and die sewage feed was shut off by closing die sewage 5 feed valve (205) during this period, so that the sludge would not be dischargcd with die water outflow (217). After the sludge lump was broken, the aération gas from the gas inlets (219 and 214) no longer entered lhe sédimentation chamber (221), the broken sludge lump gradually settled into die sludge collecting tank (224), dieu entered the aération (225) via the liquor elevating tube (216), the gas-lîquor separating 10 tank (215) and die first concentrated mixed liquor retum pipe (223), or entered die anaérobie reaction chamber via lhe second concentrated mixed liquor retum pipe (208). Thus, die sludge lump in die middle part of die upper part of the sédimentation chamber (221) was eliminated, and die sludge floating was prevenied.

Example 3

Fig.6 is a structural diagram of further anoüier embodiment of die apparatus for biological sewage treatment of the présent invention, in which lhe apparatus for biological sewage treatment was of vertical type, comprising an anaérobie réaction chamber (33), an aérobic réaction chamber or an aération chamber (26), a separating 20 chamber or a sédimentation chamber (22) and a power chamber or power room (3) as disposed in the anaérobie réaction chamber (33). All these components were arranged in a single cylindrical tower (or polygonal tower) having a height of about 10 m to about 30 m.

A gas inlet (6) was set al die bottom of lhe power chamber (3). The gas inlet (6) 25 had a gas inlet pipe (7) thaï extended downward and communicated widi atmosphère so diat atmosphcric air could enter the power chamber (3). A cover plate (5) was set above lhe gas inlet (6) so dial an operator could conveniently move in the power chamber (3). A plurality of air outlcts (4) were set at die edge of die cover plate (5) so thaï the air from the gas inlet (6) could enter die power chamber (3) and optionally 30 was guided toward a power device such as a pump ( 1 ) and an air blower (32).

A gas outlet (12) was set at die top of the power chamber (3). In some cases, die top of the power chamber (3) could bc a part of a division plate (30). The gas oudet (12) was fluidly connected with the lower part of lhe heat exchanger (13), and thus was also an gas inlet of the beat exchanger (13). The heat exchanger (13) was set in the aérobic réaction chamber (26). The gas from the gas outlet (12) passed through lhe beat exchanger (13) to perform hcal exchange with die mixed liquor in the aérobic réaction chamber (26), and Üicn was discharged from an outlel (15) al lhe top of the heat exchanger (13). In some cases, a vent (such as axial flow vent, not shown) could be set at the outlet (15) to enhance the gas flowing in the power chamber (3) and the beat exchanger (13).

The heat exchanger (13) in lhe apparatus as shown in Fig.6 can also be a single straight tube heat exchanger (13) as shown in Fig.3, in which lhe gas in the tube exchanges heat with the mixed liquor out of the tube; the heat exchanger (13) in the apparatus for biological sewage treatment as shown in Fig.6 can also be a heat exchanger (13) with a plurality of straight tubes as shown in Fig.4, in which the gas in the tubes cxchangcs heat with the mixed liquor oui of the tubes; the beat exchanger (13) in the apparatus for biological sewage treatment as shown in Fig.6 can also be a spiral tube heat exchanger (13) as shown in Fig.5, in which the gas in the spiral tube exchanges heat with lhe mixed liquor out of Uie spiral tube.

A sewage feed from a water inlet pipe (9) entered die anaérobie réaction chamber (33) via a sewage feed valve (8) and the pump (1). The sewage feed formed a laminar upflow in the anaérobie reaction chamber (33) so that the sludge in lhe anaérobie réaction chamber (33) was stably suspended under balance of flowing and settling to form n sludge bed. A clear liquor penetralcd the sludge bed and continuously flowed upward and passed through an opening (31) (preferably equipped with an unidirectional passing device, such as an one-way valve) on the division plate (30) and entered the aérobic réaction chamber (26).

An aération gas entered the aérobic reaction chamber (26) via a gas inlet pipe (10), an aération blower (32) and an aération gas distribulor (29) and aerated the mixed liquor in lhe aérobic réaction chamber (26). A suitable acrator (not shown), such as spiral aerator, micropore acrator, plaie-type aerator, rotation mixing acrator, tube aerator, jet acrator, could also be sel in the aérobic réaction chamber (26). After aération treatment, the aération gas was accumulated in upper part of the aérobic reaction chamber (26), and lhe mixed liquor of the aérobic reaction chamber (26)

entcrcd a liquor collccling lank (27). The mixcd liquor in tlie liquor collecting lhank (27) was then introduccd to the lower part of the separating chambcr (22) via a pipe (25) and separalcd into a supematant and a concentrated mixed liquor. The supematant was dischargcd as water outflow (20) via an overflow well (21). The 5 concentrated mixed liquor declined to and was collccted by a concentrated mixed liquor collecting tank (16), and then drawn via a pipe (17) lo a guiding tube (19) by using the aération gas that was introduccd to the guiding tube (19) via a pipe (23). The concentrated mixed liquor and the aération gas formed a gas-liquor mixture in the guiding tube (19) and flowed upward under the pressure and floating action of the 10 aération gas. Tlie gas-liquor mixture from the guiding tube (19) was separated lo form the aération gas and the concentrated mixed liquor again in a gas-liquor separator (18), in which the aération gas was discharged, while the concentrated mixed liquor rctumed to the lower part of the aérobic réaction chambcr (26) via a pipe (28).

Wlicn there was sludge lump or sludge floating in the separating chamber (22), 15 the valve (11) was tumed on so that a part of the concentrated mixed liquor in the concentrated mixed liquor collecting tank (16) was introduccd to the anaérobie reaction chamber (33) via a pipe (14), valve (11), pump (1) and pipe (2), in which the valve (8) was optionally tumed off.

During the operation of the apparatus of Fig,6, the gas in tlie power chamber (3) was heated by tlie heat generated by the pump (1) and Üie aération blower (32), the heated gas entered the heat cxchangcr (13), exchanged heat with tlie mixed liquor in the aérobic réaction chambcr (26), and Üicn was discharged from tlie outlet (15). The heated mixed liquor in the aérobic réaction chamber (26) could perform aérobic reaction much beltcr. Thus, the heat released by the pump (1) and the aération blower 25 (32) was recovcrcd.

In addition, the whoie apparatus of Fig,6 was concise and compact, could be convenicntly operated, occupied less area, and was easy for installation and transportation. In the meantime, power devices, monitoring instruments, control switches as well as valves were integrated in the power chambcr (3), so that tlie 30 apparatus could be convcniently, quickly imd effectively controlled and monitored.

The apparatus and method for biological sewage treatment of the présent invention can quickly and effectively control and regulale the position of the interface

between the supematant and the concentrated mixed liquor in tlie sédimentation chamber, and thus can prevenl or eliminate sludge lump and sludge floating in lhe sédimentation chamber.

The apparatus and method of the présent invention can sufficienlly utilize lhe 5 energy and oxygen of Lhe aération gas, so thaï the energy consumption and maintenance cost of whole apparatus are reduced, biological sewage treatment effects are improved, and sludge floating is prevented. In addition, the apparatus and method □f présent invention also hâve advantages of high performance, energy saving, high rcliability, good movability and miniaturization.

I0 The présent invention is illustrated with the above examples. However, those skilled would understand that the présent invention is not rcstricted to these spécifie examples. The présent invention can be modified or changed in many aspects, and ail these modifications and changes fall within the protection scope of the présent invention.

Claims (38)

1. Wlial is claimed is:

   1. An apparatus for biological sewage treatment, comprising a concentrated mixed liquor driving device which is disposed to drive a concentrated mixed liquor to flow by using a gas.

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2. 2. The apparatus for biological sewage treatment according to claim 1, wherein the concentrated mixed liquor driving device is disposed to allow tlie gas to contact with tlie concentrated mixed liquor.
3. 3. The apparatus for biological sewage treatment according to claim 1 or 2, wherein the concentrated mixed liquor driving device comprises a guiding tube, a gas

   10 inlet and a concentrated mixed liquor inlct arc set at a lower part of tlie guiding tube, a gas-liquor mixture conveying section is set at a middle part of die guiding tube, and a gas-liquor mixture outlet is sel at a upper part of tlie guiding tube.
4. 4. Tlie apparatus for biological sewage treatment according to any one of daims 1-3, wherein lhe concentrated mixed liquor driving device further comprises a

   15 gas-liquor separating device that is fluidly connected with the gas-liquor mixture oullet.
5. 5. The apparatus for biological sewage treatment according to any one of lhe preceding daims, further comprising an aération section lo provide an aération gas as lhe gas.

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6. 6. The apparatus for biological sewage treatment according lo any onc of lhe preceding daims, further comprising a sédimentation section to provide the concentrated mixed liquor.
7. 7. The apparatus for biological sewage treatment according to daim 1 or 2, further comprising an anaérobie treatment section, a sédimentation section and an 25 aération section, wherein tlie anaérobie treatment section is disposed lo receive a sewage fccd and a concentrated mixed liquor from lhe concentrated mixed liquor driving device and perform anaérobie treatment so as to obiain an anaérobie treatment mixed liquor, the aération section is disposed to receive lhe anaérobie treatment mixed liquor and perform aération treatment by contacting with an aération gas so as to 30 obtain an aération treatment mixed liquor, the sédimentation section is disposed to receive tlie aération treatment mixed liquor and perform sédimentation so as to obtain a supematant and a concentrated mixed liquor, and the concentrated mixed driving device is disposed to rcccivc tlie concentrated mixed liquor and drive tlie concentrated mixed liquor to flow by using the aération gas collected from die aération section.
8. 8. The apparatus for biological sewage treatment according to claim 7, wherein lhe aération section has a gas-liquor separating device to separate the aération treatment mixed liquor and the aération gas, tlie gas-liquor separating device is fluidly connected with the sédimentation section to allow the sédimentation section to receive lhe aération treatment mixed liquor, and the gas-liquor separating device is disposed to prevent the aération gas from entering the sédimentation section.
9. 9. The apparatus for biological sewage treatment according to claim 7, wherein lhe anaérobie treatment section, the sédimentation section and lhe aération section are disposed to form a horizontal type apparents for biological sewage treatment.
10. 10. The apparatus for biological sewage treatment according to any one of the preceding claims, wherein at least a part of lhe apparatus for biological sewage treatment is set below or above tlie ground, or tlie apparatus for biological sewage treatment is set on a movable platform.
11. 11. The apparatus for biological sewage treatment according to claim l, wherein the apparatus for biological sewage treatment is a tower-type apparatus for biological sewage treatment, comprising a sédimentation section, and a pneumatic mixed liquor elevating device as the concentrated mixed liquor driving device which is disposed to elevate tlie concentrated mixed liquor of the sédimentation section by using the gas.
12. 12. The apparatus for biological sewage treatment according toclaim 11, wherein the pneumatic mixed liquor elevating device comprises a substantivcly vertical liquor elevating tube to draw lhe concentrated mixed liquor, and a gas guiding tube which is fluidly connected willi the liquor elevating tube to introduce the gas into lhe liquor elevating tube.
13. 13. The apparatus for biological sewage treatment according to claim 12, wherein lhe liquor elevating tube has an inlet for receiving the concentrated mixed liquor and an outlet for discharging the gas and lhe concentrated mixed liquor, and lhe gas guiding tube is connected with a middlc or lower part of the liquor elevating tube.
14. 14. The apparatus for biological sewage treatment according to claim 12 or 13, wherein a sludge collecting channel is set at lhe bottom of the sédimentation section, and lhe inlet of the liquor elevating tube extends into the sludge collecting channel.
15. 15. The apparatus for biological sewage treatment according to any onc of claims 11-14, further comprising a gas-liquor separaling tank for separating the concentrated mixed liquor and tlic gas from lhe pneumatic mixed liquor elevating device.
16. 16. The apparatus for biological sewage treatment according to any onc of claims 11-14, further comprising an aération section, wherein the aération section has a gas collecting hood to collcct an aération gas in the aération section, and lhe gas collecting hood is fluidly connected with the gas guiding tube.
17. 17. The apparalus for biological sewage treatment according to claim 16, wherein the aération section further has a liquor collecting tank to collect a mixed liquor in tlie aération section, and the liquor collecting tank is fluidly connected with the sédimentation section.
18. 18. Tlic apparatus for biological sewage treatment according to claim 16 or 17, further comprising a division plate disposed between the aération section and lhe sédimentation section, wherein the division plate defines a roof of die liquor collecting tank, and the corresponding part of the division plate has a hole or pipeline through which lhe mixed liquor in the liquor collecting tank enters the sédimentation section.
19. 19. The apparalus for biological sewage treatment according to any one of claims 16-18, wherein a first concentrated mixed liquor return pipe is disposed between the gas-liquor separating tank and the aération section for inlroducing lhe concentrated mixed liquor of the gas-liquor separating tank into the aération section.
20. 20. The apparatus for biological sewage treatment according to any one of claims 16-19, further comprising an anaérobie treatment section disposed below the aération section, wherein a second concentrated mixed liquor return pipe is disposed between lhe gas-liquor separating tank and tlie anaérobie treatment section for inlroducing tlie concentrated mixed liquor of the gas-liquor separating tank into lhe anaérobie treatment section.
21. 21. The apparatus for biological sewage treatment according to any one of lhe preceding claims, further comprising a power room and a beat exchangcr, wherein tlic heat exchanger beats a mixed liquor in lhe apparatus for biological sewage treatment by using a heat released from a power device in lhe power room.
22. 22. The apparatus for biological sewage treatment according to claim 21, wherein tlie power room and tlie heat exchanger are disposed in an anaérobie

    5 treatment section and/or an aération section and/or a sédimentation section, the power room has al least one power device, a gas inlet fluidly connecting with atmosphère and a gas outlet fluidly connecting with lhe heat exchanger.
23. 23. The apparatus for biological sewage treatment according to claim 22, wherein lhe gas inlet has a gas distributor lo control the distribution of gas entering

    10 into tlie power room.
24. 24. The apparatus for biological sewage treatment according to any one of claims 1-23, further comprising a sludge lump breaking device in die sédimentation section.
25. 25. The apparatus for biological sewage treatment according to claim 24, wherein the sludge lump breaking device is an uerator or a gas distributor.

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26. 26. A method for biological sewage treatment, comprising a step of using a gas to drive a concentrated mixed liquor to flow.
27. 27. The method for biological sewage treatment according lo claim 26, wherein tlie gas contacts with the concentrated mixed liquor.
28. 28. The method for biological sewage treatment according to claim 26 or 27, 20 wherein al least part of the gas is an oxygen-containing gas.
29. 29. The method for biological sewage treatment according to claim 28, wherein lhe oxygen-containing gas is an aération gas.
30. 30. The method for biological sewage treatment according to any one of claims 26-29, wherein the concentrated mixed liquor is from a sédimentation section.

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31. 31. The method for biological sewage treatment according to claim 30, further comprising introducing a sewage feed and die concentrated mixed liquor to an anaérobie treatment section to perform anaérobie treatment and obtain an anaérobie treatment mixed liquor, introducing the anaérobie treatment mixed liquor to an aération section lo perform aération treatment with an aération gas and obtain an

    30 aération treatment mixed liquor, introducing the aération treatment mixed liquor to a sédimentation section to perform sédimentation treatment and obtain a supematant and the concentrated mixed liquor, and using lhe aération gas collected from the aération section as the gas to drive the concentrated mixed liquor to flow.
32. 32. The method for biological sewage treatment according lo any one of claims 31, further comprising subjecting the supematant in the sédimentation section to aération treatment periodically or when a sludge lump appears or is about to appear in lhe supematant.
33. 33. The method for biological sewage treatment according to any one of claims 31-32, further comprising introducing at least part of the concentrated mixed liquor of lhe sédimentation section to the anaérobie treatment section.
34. 34. The method for biological sewage treatment according to any one of claims 26-33, further comprising a step of heating a mixed liquor using a heat releascd from a power device.
35. 35. The method for biological sewage treatment according to any one of claim 26-34, wherein tlie gas is used to elevatc the concentrated mixed liquor.
36. 36. The method for biological sewage treatment according to claim 35, further collecting a mixed liquor and an aération gas in an aération section, subjecting the mixed liquor to sédimentation treatment in a sédimentation section to obtain a supematant and a concentrated mixed liquor, and elevating the concentrated mixed liquor in a pneumatic mixed liquor elevating device by using tlie aération gas.
37. 37. The method for biological sewage treatment according to claim 35, further comprising separating in a gas-liquor separating tank the aération gas and the concentrated mixed liquor from tlie pneumatic mixed liquor elevating device, and introducing at least part of lhe separated concentrated mixed liquor to lhe aération section.
38. 38. A method for biological sewage treatment, comprising using the apparatus for biological sewage treatment according to any one of claims 1-25 to perform lhe biological sewage treatment.