DE102010049709B3 - Clear water compressed air lift for biological sewage treatment plants, process for its operation and its use - Google Patents

Abstract

The present invention relates to a clear water compressed air lifter for biological sewage treatment plants with a backwash function to avoid or reduce the discharge of activated sludge particles, a method for its operation and its use. The object of the invention to provide a clear water lifter for biological sewage treatment plants and a method for its operation, which allow clear water to be pumped out in the reactor of the sewage treatment plant directly under the water surface at the end of the settling phase, so that bacterial concentrations in the clear water that exceed the specified limit values are not transported is achieved in that the clear water compressed air lifter with backwash function comprising a suction pipe (11) with a suction opening (10) in its wall and a siphon pipe (13), the suction pipe (11) and the siphon pipe (13) having a common connecting space, a compressed air line (17) with an air inlet opening (18), the air inlet opening (18) opening into the siphon pipe (13), and a curved drain pipe (14) with water buffer (24) which is connected to the siphon pipe (13), see above that a water conduction path from the suction opening (10) through the suction pipe (11) into the siphon pipe (13) towards the drain pipe (14) is formed, with a cladding tube (19) divided in the middle by a partition (23), which is closed at one end with a base (191) and at its other, open end merges into the drainage tube (14), the suction tube (11 ) and the siphon pipe (13) each has a semicircular cross-section, the partition (23) with a 360 ° -shaped apex between the suction pipe (11) and the siphon pipe (13) forms a connecting arc (12) in which their distance to The bottom (191) of the cladding tube (19) is approximately half the diameter of the cladding tube (19), the air inlet opening (18) on or in the central wall (23) on the side of the siphon tube (13) in the immediate vicinity of the apex of the partition ( 23), the suction pipe (11) above the suction opening (10) is closed with a foam partition (22) and the side opening of the drain pipe (14) is reduced by almost half its pipe diameter, so that the water buffer (24) is formed is.

Description

The present invention relates to a clear water compressed air lift for biological sewage treatment plants with backwash function to prevent or reduce the discharge of activated sludge particles, a method for its operation and its use.

In almost all biological sewage treatment plants, which do not work with electric underwater pumps, but with a compressed air generator, also called compressor or compressor, work, compressed air lifters are necessary to promote the domestic wastewater from one basin to another, or the resulting clear water in the flow of To pump sewage treatment plant. Air lifters consist of a tube open on both sides with a compressed air connection on the side. The air jacks are mounted vertically in the treatment plants so that the compressed air connection is as far below the water level as possible, that the suction opening of the pipe can aspirate water to the desired height and the outlet of the pipe is placed where the pumped water is to be discharged. If there is enough water in the wastewater treatment plant, so that the siphon tube above the compressed air connection is well filled with water, then, with the compressed air generator switched on, the compressed air flows through the air inlet opening into the siphon tube and conveys the water vertically upwards. The resulting air bubbles tear the surrounding water in the pipe upwards and thus promote the inflowing water through the outlet opening of the siphon tube.

This pumping process lasts until the water level in the wastewater treatment tank is lowered so that the shortened path in the siphon tube, the buoyancy forces of the high-flowing air bubbles no longer entrain water, or the compressed air generator is turned off. In biological wastewater treatment plants, especially in SBR wastewater treatment plants, the inflowing wastewater is stored in a pre-treatment tank in order to be pumped into a SBR reactor after a cycle of several hours.

In the reactor basin, also referred to as reactor, the wastewater is aerated by plate or pipe aerator feinperlig. Through this ventilation, the freely floating bacteria can breathe there and purify the wastewater through their metabolic processes. After this cleaning phase, the ventilation is switched off, so that the bacteria can settle by sinking on the ground. After this settling phase, a clear water zone is formed above the bacterial layer, which is then pumped by the clear water elevator, in the same function as described, into the outlet of the sewage treatment plant.

At the same time, excess bacteria are pumped into the primary clarifier by the surplus sludge lifter operated in parallel with the clear water jack, to a lesser extent because of the smaller sized siphon tube.

After this clear water pumping time, the sewage treatment cycle begins again with the feed pumping time, in which the feed lifter pumps the pre-treatment water into the reactor in preprogrammed time. The compressed air for the feed lifter, for the plate ventilator and for the clear water or excess sludge lifter is switched via individual electromagnetically actuated valves. These valves are supplied with compressed air via a compressed air compressor.

For these reasons, the prior art airlifts are designed so that its suction port is below the water surface and the pump down operation is achieved when no water can flow over the lower edge of the suction port (see 1 ). Due to this need to pump out the upper clear water area and not the underlying area of settled bacteria, it is necessary to guide the intake pipe following the intake vertically downwards and over a U-shaped 360 degree arc with the following vertically upwards to connect the following siphon pipe. So that buoyancy forces of the compressed air bubbles flowing into the siphon pipe are greatest, the air inlet opening attached laterally to the siphon pipe must be as deep as possible, but above the pipe bend.

The so designed by almost all manufacturers clear water has the disadvantage that the pre-treatment runs when filling the reactor by means of feed lifter in the intake of the clear water lifter and can settle there floating particles.

The pollution of the clear water is done in systems according to the prior art far from intensive in the subsequent aeration process by the ascending when switching the plate, tube, Membranbelüfters air bubbles increase first in the water volume in the reactor and secondly swirl the settled activated sludge bacteria in the reactor water , So that they pass through the increase in volume also through the intake into the intake pipe of the clear water jack and also settle there. The ventilation period in the reactor of an SBR treatment plant often takes several hours. The plate or Rohrmembranbelüfter is therefore switched on and off in this period in the preselected cycle, so that at least every time ventilation begins again and again activated sludge bacteria because of Volume increase are pressed into the clear water jack. Since the activated sludge bacteria are heavier than water, they sink down in the intake pipe and fill the pipe bends, which connect the intake pipe and the siphon pipe. At the beginning of the clear water pumping time, the clear water lift conveys these deposits into the wastewater treatment plant effluent.

This is easy to see in practice, because the first pump surges have the color of the activated sludge bacteria. In the further pumping the clear water is rinsed by sucked clear water so that all pipe deposits are carried away. And only clear water from the clear water zone of the reactor is conveyed into the drain of the sewage treatment plant.

A disadvantage is thus in plants according to the prior art that activated sludge bacteria in this way constantly get out of the sewage treatment plant in the drain. This so-called activated sludge stripping has the consequence that in the reactor, the activated sludge volume is constantly reduced and thus also the wastewater treatment performance. It is particularly disadvantageous if there is a seepage behind the sewage treatment plant run, which is slowly silted up and rendered useless by the sludge removal.

The same applies if there is a receiving water downstream of the clarification system, which creates an imbalance due to the sludge load and the associated oxygen reduction in the water of the receiving water. Another disadvantage is that there are no compressed air lifter, in which the clogged suction port of the feeder jack, by a suitable backwashing eliminates this obstruction.

To solve these drawbacks, a clear water lifter should be designed so that no activated sludge mixture can penetrate into the intake, or that settled activated sludge is flushed back from the clear water jack into the reactor before the clear water pumping time and thereby the littering of infiltrations, as well as the contamination of bodies of water is avoided.

In practice and from published patent applications, some solution variants are realized or known, which are intended to counteract the disadvantages described.

According to DE 20 2005 019 918 U1 For example, check valves are attached to the intake openings of the clear water lift pipe in order to prevent the activated sludge bacteria from penetrating there. Many years of experience have shown that the hair floating in the sewage or similar parts wrap around the movable flaps or valves in such a way that the desired closure forces no longer have an effect after some time or have to be constantly cleaned by time-consuming maintenance work.

In DE 10 2008 038 116 A1 and DE 10 2007 049 517 A1 It is proposed to filter the particulate matter and the activated sludge bacteria with filter devices so that they are collected in the filters and can not leave the treatment plant. For this purpose, signaling devices are necessary, which indicate the level of the filter, and signal the necessary filter cleaning. The disadvantage here is that the activated sludge bacteria are not returned to the reactor, but lost for the cleaning process. In addition, the filtration and maintenance of the filters are very expensive.

DE 20 2005 003 588 U1 discloses a small wastewater treatment plant with a pre-clearing chamber and a secondary clarifier, wherein in each chamber at least one air lift is provided with the air under the appropriate medium in the sense of lifting from the respective chamber can be conveyed, with each compressed air lifter associated, connected to a compressed air unit compressed air line in a lever line is arranged, wherein the medium can be guided by the intermediate space formed between the outer wall of the compressed air line and the inner wall of the lifting line.

DE 24 20 076 A1 discloses an apparatus for continuously introducing oxygen into waste water under elevated hydrostatic pressure, wherein a gas inlet is arranged in the lower part of a shaft, and a liquid inlet and a liquid outlet is arranged on a reservoir arranged above the shaft and connected thereto.

Out DE 24 23 085 A For example, there is known a method of treating waste water, which comprises a step of circulating the waste water in a system comprising a descending and an ascending part communicating at their upper and lower ends, wherein an oxygen-containing gas such as oxygen itself or an oxygen-containing gas mixture is supplied to the wastewater as it passes through the descending part.

Further solutions are, for example, in DE 10 2007 058 177 A1 . DE 10 2008 020 938 A1 and in EP 1 582 263 B1 disclosed. According to these proposed solutions is attempted by Strömungsableitvorrichtungen at the intake of the clear water jack the ingress of activated sludge during the ventilation in the reactor to prevent. Through certain pipe arrangements is trying to keep away during the aeration water-activated sludge mixture of the direct suction port of the suction pipe from the clear water jack, or to calm down in a kind of buffer tube. However, these proposals do not take into account that an increase in volume occurs at the beginning of each ventilation. The increase in volume causes an overpressure in relation to the open-sided clear water lift tube on both sides and tries to compensate for this. Thus, in any event, at each start of aeration, the water-activated sludge mixture flows into the intake port of the clear water elevator to settle to the bottom of the U-shaped 360 degree arc. Thus reduce the in DE 10 2007 058 177 A1 . DE 10 2008 020 938 A1 and in EP 1 582 263 B1 measures described only the activated sludge output.

DE 100 57 378 B4 discloses an electric underwater pump as a clear water pump, which should pump the clear water from the clear water area in the flow of the sewage treatment plant.

Activated sludge deposits from the previous aeration cycle occurring in the pump are eliminated by one or more pump strokes according to this technical solution. So it is briefly pumped water in the output side riser so that it flows in free fall through the pump and entrains the lying there activated sludge and flow into the reactor. However, this good operation of a hydraulic flushing is not possible with the same application in the compressed air driven clear water heater because of the closed down 360-degree U-bend. In tests it was tried to carry out this hydraulic backwashing at the clear water lifter practically. The water column in the siphon pipe was raised by a brief burst of compressed air, and the inflowing water necessary for this was low, since the increase in volume in the riser pipe largely stems from the inflowing air bubbles. The falling water column, must first separate from the rising air bubbles and therefore does not have the speed required to take the activated sludge in the U-shaped pipe part so that it ascends to the suction port to get there into the reactor water. The process was repeated with a buffer tank attached above the outlet of the siphon tube. When you press the clear water, so this is first filled with water before the clear water can drain laterally from this. To generate a rinse, the clear water lifter is briefly turned on until the buffer tank is filled and not overflowing. When the clear water jack is switched off, the water from the buffer tank flows back into the jack and pushes the buffered water back through the suction port into the reactor. The activated sludge fraction flushed out in this way is small and corresponds only to the amount of clarified-water-sludge mixture of the volume of the buffer container. The buffer tank can and must not be too large, because its water back pressure greatly reduces the head and the capacity of the clear water lifter. In addition, the flow rate of the recirculating water is not sufficient to entrain the activated sludge deposits at the bottom of the U-shaped pipe bend.

The above-described hydraulic backwashing of the activated sludge bacteria is therefore unsatisfactory.

The invention is therefore an object of the invention to provide a clear water for biological treatment plants and processes for its operation, which allow the pumping of clear water in the reactor of the treatment plant directly below the water surface at the end of the settling phase, so that not bacterial concentrations are transported to the clear water, which exceed the specified limits.

This object is achieved by a clear water for biological wastewater treatment plants according to the first claim, a method for its operation according to the seventh claim and its use according to the ninth claim. Advantageous embodiments of the invention are specified in the subordinate claims.

The essence of the invention is that the clear water lifter is designed to operate in a combination of hydraulic and pneumatic backwash in such a manner that the activated sludge is flushed into the reactor and only a small buffer tank is needed at the exit of the siphon tube ,

For this purpose, the clear water compressed air lift with backwash function comprises an intake manifold with a suction port in the wall and a siphon tube, wherein the suction pipe and the siphon have a common connection space, and a compressed air line with an air inlet opening, wherein the air inlet opening into the siphon tube, and a curved drain pipe with water buffer, which is connected to the siphon tube, so that a Wasserleitweg is formed by the suction port through the intake pipe in the siphon tube to the drain pipe.

A centrally divided by a partition wall tube, which is closed at one end with a bottom and at the other, According to the invention, the intake end and the siphon tube each have a semicircular cross-section, wherein the cross-sectional area of the discharge tube is almost twice as large as the cross-sectional area of the siphon tube.

The partition forms according to the invention at the same time by their 360 ° -shaped vertex between the intake manifold and the siphon pipe a connecting arc, with their distance from the bottom of the cladding tube is approximately half the diameter of the cladding tube.

It is essential that the air inlet opening thereby hangs on or in the middle wall and is positioned on the side of the siphon in the immediate vicinity of the apex of the partition, wherein the intake pipe above the suction port with a partition, eg. From foam, is closed and through this foreclosure no air can get.

The lateral opening of the drain pipe is reduced by approximately half of its pipe diameter, so that a small water buffer is formed.

According to the invention, the clear water lifter according to the invention is briefly turned on until the buffer tank is filled with water and its drain pipe does not overflow. Thereafter, the clear water jack is switched off immediately.

Shortly after the shutdown, the buffered water flows back into the siphon tube through the U-shaped pipe bend in the direction of the suction port.

Exactly at the beginning of this return flow, the compressed air is turned on again, so that the water flow diverts the emerging compressed air at the air inlet opening in the opposite direction through the U-shaped pipe bend in the ascending intake pipe, whereby the air bubbles rising in the intake pipe, the activated sludge-water mixture through the intake opening in let the reactor flow, wherein at the same time in the siphon pipe, a negative pressure is formed, which promotes the water there located to a minimum.

After switching off the briefly supplied compressed air flows mainly clear water into the intake and fills the clear water.

After repeated operation of the process described during the clear water phase, the tube of the clear water jack is almost completely purified by activated sludge bacteria and the actual clear water pumping time can without downforce of. Activated sludge bacteria are introduced.

It is important that the redirected air flow can flow quickly and in a very short ways in the ascending intake manifold, because by this momentum in the siphon quickly creates a negative pressure, the water located there sucks to a minimum and the back flowing water of the buffer tank only the Deflection process of the air flow initiates, so that the buffer volume of the buffer tank must be small.

It is also important that the air passage opening for the inflowing compressed air is attached at the point in the clear water jack, where the deepest vertex between the intake manifold and the siphon is because there is also the largest flow rate of the flowing water.

To increase the lift and the Rückspüleffektivität the inventive air pressure lifter is constructed as follows:
The suction and the siphon tube are not separate tubes with a bottom-mounted U-shaped pipe connection, but these are inventively formed from a centrally divided by a partition casing tube by the suction and the siphon tube seen in cross-section at the lower end hydraulically connectable tube halves represent. The cross section of the intake pipe and the siphon tube is, for example, semicircular.

In the context of the invention is also that the cladding tube in its cross section a different geometric shape than the circular shape and the suction and the siphon have a different geometric shape than the semicircular shape, in which the cladding in its cross-section angular, for example, four or is triangular executed.

The formation of the semicircular suction in the cross section and the semi-circular in cross-section siphon tube is, for example, feasible by in one through a bottom closed on one side, circular in cross-section plastic tube a slightly oversized with respect to the inner tube diameter made middle wall is pushed so far into a plastic tube , until between the end of the middle wall and the tube sheet, a distance arises, which corresponds to half the pipe diameter.

At the inserted middle wall, a compressed air line is attached, which has its air inlet opening at the lower end of the middle wall on a wall side. In this way, two seen in cross section semicircular, at the bottom of hydraulically connected tube halves educated. On the side on which the air passage opening of the compressed air line is located at the middle wall, the semicircular siphon tube is formed and on the opposite side, the semicircular suction pipe is formed at the desired height due to a suction opening in the cladding tube.

Above the suction opening, the semicircular tube is advantageously sealed off with a semicircular foam cushion, so that the bubbles rising there for a short time during the backwashing effect can leave the semicircular tube with the activated sludge-water mixture.

Now, if an at least right-angled pipe bend is placed on top of the cladding tube, the water pumped up through the siphon pipe during normal operation can flow off above this pipe angle. It is important that this pipe bend has almost twice the diameter of the semicircular siphon tube, ie the diameter of the cladding tube, so that the air of the pumped-up air-water mixture at the top of the pipe bend can escape easily and so no back pressure on the air-water mixture Pillar generated in the siphon tube.

Essential to the invention in this clear water is that the air inlet opening of the incoming compressed air via the compressed air line still on the side of the semi-circular siphon tube, but directly to the 360 degree-shaped pointed turn of the two vertically upwardly leading semicircular tubes (apex between lift and intake manifold) ,

It is also within the scope of the invention that the above-described clear water lift is used as a feed elevator, in which the backwashing effect according to the invention briefly eliminates the blockages occurring in the case of a feed lift by the compressed air bubbles flowing out at the suction opening.

The advantage of this technical solution according to the invention (clear water lift and feed lifter) is, in particular, that the water volume of the water buffer only needs to be so great that its returning water flow in the siphon pipe deflects the short-term compressed air flow supplied, so that this, as described above, into the intake pipe is redirected in a very short ways and immediately in its own momentum by these rising air bubbles in the semicircular siphon through the negative pressure generated there, the water there is largely conveyed away.

Another advantage over the known clear water boilers lies in the simple, effective design and the resulting low installation effort, resulting in a cheap and powerful clear water with backwash.

The invention will be explained in more detail below with reference to the embodiment and the figure. Showing:

1 : A schematic representation of a compressed air-driven SBR plant according to the prior art and

2 : A schematic detail of an embodiment of the clear water compressed air lifter according to the invention with backwash function.

In 1 1 is a schematic representation of a prior art compressed air operated SBR system in which electromagnetic air valves (FIG. 1 ) from the compressor ( 2 ) switched compressed air. These compressed air valves ( 1 ) are controlled by the controller ( 3 ) electrically controlled. A valve ( 1 ) switches the air to the feed elevator ( 4 ), which in the pre-treatment water ( 5 ) is placed. Another valve ( 1 ) switches the air to the plate fan ( 6 ). A third valve ( 1 ) switches the common air in the reactor ( 7 ) placed clear water lifter ( 8th ) and for the excess sludge 9 ).

All three compressed air lifts ( 4 . 8th and 9 ) convey the water through a suction port ( 10 ) in the intake pipe ( 11 ) over a U-shaped 360 ° arc ( 12 ) in the siphon ( 13 ) and a pipe angle ( 14 ) in another basin, or in the treatment plant flow disadvantage of this technical solution is that if the clear water 8th ) the clear water from the reactor ( 7 ) to the minimum water level ( 15 ) and then the feeder lifter ( 4 ) the pre-treatment water containing particles and suspended matter ( 5 ) in the reactor ( 7 ) until the upper maximum water level ( 16 ) is reached, even this heavily contaminated pre-treatment water naturally in the intake ( 10 ) of the clear water lifter ( 8th ) and thereby in the subsequent ventilation phase from the plate ventilator ( 6 ) ascending air bubbles the volume in the reactor ( 7 ), so that the fluidized activated sludge bacteria located in the reactor water by this volume compensation in the intake ( 10 ) of the clear water lifter ( 8th ), to there in the intake pipe ( 11 ) and in the U-shaped 360 ° arc ( 12 ) to sediment.

As a negative consequence, these deposits are promoted in the following Klarwasserabpumpphase with the first pump surges in the flow of the sewage treatment plant. To this discharge of activated sludge particles and other deposited particles To prevent these parts would have to be in the reactor water of the reactor as follows ( 7 ) are backwashed:
It is briefly compressed air via the valve ( 1 ) and through the hose line ( 17 ) down into the siphon tube ( 13 ) of the clear water lifter ( 8th ) in the air inlet opening ( 18 ), so that the surface of the water column until shortly before the outflow of the Rohbogens ( 14 ) is raised. After switching off the compressed air, the water column falls down and generated at the air inlet ( 18 ) an opposite water flow, so that when switching on the compressed air at this moment, the largest flow of water, the introduced air bubbles are entrained so that this deflected into the intake pipe ( 11 ), can rise there to pass through the intake ( 10 ) in the reactor ( 7 ) to flow into the surrounding reactor water.

The rising compressed air bubbles in the intake pipe ( 11 ) briefly generate a negative pressure in the siphon ( 13 ) and thus promote the largest part of the water volume in the siphon ( 13 ) through the U-shaped 360 ° pipe bend ( 12 ) in the intake pipe ( 11 ) to the intake opening ( 10 ) in the reactor ( 7 ). After this brief rinsing process during the clear water phase, the compressed air is switched off and the clear water ( 8th ) fills with clear water again.

The design of this air pressure lifter according to 1 , which is operated as before standing, is due to its complex operation only conditionally for a hydraulic-pneumatic backwashing.

The in 2 illustrated clear water compressed air lift with backwash function includes a centrally through a partition ( 23 ) split tube, as a cladding tube ( 19 ) and is closed at one end and at its other, open end in a curved drain pipe ( 14 ), which is, for example, 90 degrees angled, wherein the cross-sectional area of the drain pipe ( 14 ) is almost twice as large as the cross-sectional area of the siphon tube ( 13 ).

This ratio of the cross-sectional areas causes the high-pumped clear-water-air mixture to be easily separated at the said transition in such a way that the air of the compressed-air bubbles flows over the upper region of the drainage pipe (FIG. 14 ) and at the bottom of the drainpipe ( 14 ) drains the clear water, so that a back pressure against the in the siphon ( 13 ) located clear water is avoided.

The partition ( 23 ) is designed thin-walled.

The cladding tube ( 19 ) has at its one end (the lower end) on a bottom which the cladding tube ( 19 ) tightly closes.

The partition ( 23 ) has a distance to the bottom of the cladding tube ( 19 ), which is approximately half the diameter of the cladding tube ( 19 ), so that a hydraulic connecting bow ( 12 ) with a 360 ° vertex between the semicircular intake pipe ( 11 ), which has a suction opening ( 10 ) having.

An air inlet ( 18 ), via which the compressed air can flow, lies on or in the middle wall ( 23 ) on the side of the semicircular siphon ( 13 ) in the immediate vicinity of the 360 ° vertex [the lower edge of the partition ( 23 )].

The influx of compressed air into the air inlet ( 18 ) can, for example, by a compressed air hose ( 17 ), which enters the air inlet ( 18 ) and on the side of the semicircular intake pipe ( 11 ) on the middle wall ( 23 ) is guided upwards and fixed.

Above the intake opening ( 10 ) is the semicircular intake pipe ( 11 ) with a semicircular closure in the form of a foam partition ( 22 ), which the intake pipe ( 11 ) between middle wall ( 23 ) and this section of the cladding tube ( 19 ) closes, so that there with the backwash effect briefly ascending bubbles with the activated sludge-water mixture, the intake pipe ( 11 ) being able to leave.

The drainpipe ( 14 ) is on top of the cladding tube ( 19 ) fitted form-fitting, wherein the lateral outlet of the drain pipe ( 14 ) approximately half the pipe diameter of the siphon tube ( 13 ) and is located at the pipe top edge, so that the necessary for the backwashing water buffer ( 24 ).

During normal operation of the clear water compressed air lifter according to the invention, compressed air is blown over the compressed air hose for backwashing. 17 ) in the air inlet opening ( 18 ) in the semicircular siphon ( 13 ) until the water column is raised, and this water buffer ( 24 ).

When the compressed air is switched off, the water column and the water of the water buffer ( 24 ) in the siphon ( 13 ) downward. At the moment of this hydraulic return flow, compressed air is again supplied via the air inlet ( 18 ), so that the water flow and the compressed air bubbles, which from the air inlet opening ( 18 ) flow out to the edge of the thin-walled middle wall ( 23 ) in the semicircular intake pipe ( 11 ) and the rising there bubbles, which through the suction port ( 10 ), a negative pressure in the semicircular siphon ( 13 ) produce. In this case, the largest part of the activated sludge-water mixture located there is also through the intake ( 10 ) are returned to the clear water present in the clear water phase.

After this brief backwashing process, the compressed air is switched off and the cladding tube ( 19 ) fills up via the suction opening ( 10 ) again with clear water from the reactor ( 7 ).

After several backwash cycles, the cladding tube ( 19 ) of deposits from the previously performed filling and the ventilation operations cleaned. If the described backwash process is a feed lifter ( 4 ), which heavily polluted water from the primary treatment ( 5 ) in the reactor ( 7 ), so during the backwashing process from the suction ( 10 ) short-term compressed air bubbles possible mechanical blockages at the intake ( 10 ) remove.

All features described in the description, the exemplary embodiments and the following claims may be essential to the invention both individually and in any combination with one another.

LIST OF REFERENCE NUMBERS

1

Valve (electromagnetic one-way valve)

2

Compressor (compressed air generator)

3

Control (electric / electronic control)

4

Feed lifter (compressed air generator)

5

Primary treatment (pre-treatment tank)

6

Disc diffusers

7

reactor

8th

Clear water lifter (compressed air lift)

9

Excess sludge lift (compressed air lift)

10

suction

11

Intake manifold (semicircular intake manifold)

12

U-shaped, 360 ° elbow / hydraulic connecting bow

13

siphon tube

14

drain pipe

15

lower minimum water level

16

upper maximum water level

17

Compressed air line

18

Air inlet opening

19

cladding tube

20

pipe support

21

bacteria layer

22

foam foreclosure

23

center wall

24

water buffer

Claims (9)

Clear water compressed air lift with backwash function comprising • an intake manifold ( 11 ) with a suction opening ( 10 ) in its wall and a siphon ( 13 ), wherein the intake pipe ( 11 ) and the siphon ( 13 ) have a common connection space, • a compressed air line ( 17 ) with an air inlet opening ( 18 ), wherein the air inlet opening ( 18 ) in the siphon ( 13 ), and • a curved drain pipe ( 14 ) with water buffer ( 24 ), which with the siphon ( 13 ), so that a Wasserleitweg from the suction port ( 10 ) through the intake pipe ( 11 ) in the siphon ( 13 ) to the drain pipe ( 14 ), characterized in that • a centrally through a partition ( 23 ) split cladding tube ( 19 ), which is closed at its one end with a bottom and at its other, open end in the drain pipe ( 14 ), the intake pipe ( 11 ) and the siphon ( 13 ), • the partition wall ( 23 ) at its lower edge at its apex between siphon tube ( 13 ) and intake pipe ( 11 ) a connection sheet ( 12 ) forms with a 360 ° -shaped reversal of the two vertically upwardly leading tubes, wherein the connecting arc ( 12 ) the distance of the partition ( 23 ) to the bottom of the cladding tube ( 19 ) approximately half the diameter of the cladding tube ( 19 ), • the air inlet opening ( 18 ) on or in the partition wall ( 23 ) on the side of the siphon ( 13 ) in the immediate vicinity of the apex of the partition ( 23 ), • the intake pipe ( 11 ) above the suction opening ( 10 ) with a foreclosure ( 22 ) is closed and • the lateral opening of the drainpipe ( 14 ) is reduced by approximately half of its pipe diameter, so that the water buffer ( 24 ) is trained. Clear water compressed air lift with backwash function according to claim 1, characterized in that the cladding tube ( 19 ) a circular and the intake pipe ( 11 ) as well as the siphon tube ( 13 ) have a semicircular cross section or that the cross section of the cladding tube ( 19 ), of the intake pipe ( 11 ) and the siphon ( 13 ) is angular. Clear water compressed air lift with backwash function according to claim 1, characterized in that the partition ( 23 ) is thin and the foreclosure ( 22 ) consists of foam. Clear water compressed air lift with backwash function according to claim 1, characterized in that the compressed air hose ( 17 ) on the partition ( 23 ) on the side of the intake pipe ( 11 ) is guided and fixed. Clear water compressed air lift with backwash function according to claim 1, characterized in that the connection bend ( 12 ) is very short compared to the diameter of the cladding tube. Clear water compressed air lift with backwash function according to claim 1, characterized in that the drainpipe ( 14 ) opposite the cladding tube ( 19 ) is bent by 90 ° and the cross-sectional area of the drain pipe ( 14 ) is approximately twice as large as the cross-sectional area of the siphon tube ( 13 ). Method using a clear water compressed air lift with backwashing function according to one or more of the preceding claims 1 to 6 in a reactor ( 7 ) with clear water phase at the • through the air inlet opening ( 18 ) Compressed air is supplied, so that upflowing compressed air bubbles in the siphon ( 13 ) and the water column in the siphon ( 13 ) by from the clear water phase of the reactor ( 7 ) via the suction opening ( 10 ) and the siphon ( 13 ) inflowing clear water to the lower edge of the drain pipe ( 14 ) is lifted, then the compressed air supply is switched off, so that the water column in the opposite direction in the siphon ( 13 ) flows downwards, • at the time of the largest hydraulic flow in the siphon tube ( 13 ) at the air inlet ( 18 ) the compressed air is supplied again, so that the compressed air bubbles through the pipe bend ( 12 ) in the intake pipe ( 11 ), ascending the intake pipe there ( 11 ) via the suction opening ( 10 ) in the reactor ( 7 ) and thereby briefly in the siphon ( 13 ) a negative pressure is generated, which the water located there in part via the intake pipe ( 11 ) and through the suction opening ( 10 ) in the reactor ( 7 ) and, after switching off the compressed air in the opposite direction, clear water from the clear water phase of the reactor ( 7 ) in the cladding tube ( 19 ) flows and this fills, so that the water column in the siphon ( 13 ) back to the lower edge of the drain pipe ( 14 ) is raised. A method according to claim 7, characterized in that the clear water compressed air lift with backwashing function during the process vertically in the reactor ( 7 ) is positioned. Use of a clear water compressed air lift with backwash function according to one or more of the preceding claims 1 to 6 as a load lifter with clogging removal function.

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