DE2225465A1 - Wastewater treatment process and device for its implementation - Google Patents

Description

17055/71

A-8

Wastewater treatment process and device for it

execution

Wastewater treatment systems known construction usually require large structures, in order to achieve adequate ventilation of the liquid in the aeration tanks, which should in turn have to facilitate the treatment with oxygen, a large surface area ₀

The invention provides for extensive ventilation and Circulation of the liquid from one or more ventilation containers through at least one biological filter, the liquid would normally be in the aeration tank or in the aeration tanks either mechanically or ventilated by surface ventilation «The mechanical ventilation could be provided by a paddle wheel in a ring vent.

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container made. The aerated liquid is from the Aeration container or the aeration containers removed, and suspended solids are separated by electrolytic flotation. It has been found to be the case with sewage with a high content of fiber material, for example agricultural or livestock wastewater, is desirable, the hair, fibers and other similar solid suspended matter, which are kept in suspension in the receptacle,> remove,

The invention specifically provides a method of cleaning of wastewater, in which coarse solids are removed from the wastewater, the withdrawn liquid at least is fed to an aeration tank, the liquid from the ventilation tank through at least one biological Filter and circulated back into the at least one ventilation tank and solid suspended matter out of the liquid withdrawn from the aeration tank electrolytic flotation are separated "

In the preferred embodiment of the invention is between the aeration tank or the aeration tank and several biological filters a distribution tank switched on. From the distribution tank, the

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3 1225465

Liquid to an electrolytic flotation tank be returned, in which the solid suspended matter are separated.

It is sometimes preferable to alternate the flow of the liquid to the biological filters and the separation of the suspended solids. Once the operation has started, the separation of the suspended solids can be carried out continuously and simultaneously with the circulation of the liquid, in which case the inflow of the liquid to the aeration tank or tanks should be equal to or substantially equal to the extent of the discharge be liquid laden with suspended solids for the separation of the suspended solids. Of course, the flow of liquid to the aeration tanks may be continuous, while the liquid can be withdrawn for separation of the solid Schwebstöffe at predetermined time intervals _tt The preliminary method steps of the invention may dilution of the waste water and then the proportional discharge of waste water in the aeration tank or "the aeration tank including ,. It is often expedient to carry out the method according to the invention on the basis of a time cycle. Advantageously, a

ζ -

Cycle of 24 hours can be used.

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The length of stay of the sewage in any Part of the device depends on the type of wastewater to be treated, on dilution factors as well as on the type of used filter.

The invention also provides an apparatus for carrying out the method according to the invention, which is equipped is equipped with facilities for collecting the waste water and for separating coarse solids, one or more aeration tanks, one or more biological filters, facilities to separate solid suspended matter from the liquid removed from the aeration tank electrolytic flotation and controllable devices for pumping the waste water through each of these mentioned units

The device would normally have a day receptacle have, which is preferably at a lower level than the ventilation container and expediently below Floor level * and from which the wastewater is sucked to the separator for the coarse solids. That Wastewater can be pre-aerated or otherwise stirred in the receiving container by means of a screw agitator will. The receiving container can be filled with sewage from a soaking pit (macerator pit) can be filled up »It can be the

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Waste water volume obtained from the soaking pit in which the Waste water is thoroughly stirred and soaked. This pit can be used as a central collection area or container to be viewed as. The container can be available at any installation location, and in the container can be used for Reduction of the size of the pests in the sewage using a grinder or auger ”. the Soaking pit is also equipped with a pump for pumping the sewage from the soaking pit into the sewage receiving tank equipped ,, The level of the wastewater contained in it can be determined by supplying one or more in the clarification basins provided for the system are maintained. To maintain a predetermined depth of the Waste water level sensors or level probes could be provided, and the addition of water to the receptacle can be in take place at predetermined time intervals or continuously » The solids separated from the suspension can expediently be returned to the wastewater absorption, and it will be understood that such solids can simply be returned to the receptacle, if one is provided «Advantageous catfish can be part of the by Flotation separated solid suspended solids are removed via an overflow pipe, and another part of the solid Suspended matter sinks to the bottom of the electrolytic flotation tank and is over a sludge settling tank

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eliminated.

If desired, the waste water can also be passed through filters made of silica sand and / or activated charcoal. It can be seen that, depending on the number and type of filtration stages, the wastewater can be given different, predeterminable degrees of purity _e

With the electrolytic flotation the separation can be done with the help of electrodes which are connected to a direct current network are intermittent or continuous. To absorb the liquid flow from the electrolytic Settling basins can be provided with Banks filters, and several filter batteries can be cascaded in series be. Reusable water can be taken from the bottom of these Banks filters to wash them off and some form of sterilization may be provided when this water is circulated, for example water sterilization by means of ultraviolet radiation and / or chemical additives.

If silica sand filters are used, these can placed at the ends of the Banks filter and automatically washable. At the exit from the plant can be used as a facility activated charcoal filters can be used for final cleaning.

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In a preferred embodiment, the coarse material separator has an open-mesh conveying device, a line device for supplying liquid loaded with solids to the conveying device, an air supply device arranged behind the line device for directing an air jet onto the liquid loaded with solids on the conveyor and an air supply device arranged behind the air supply device Brush device for brushing off the ₉ air-treated solids adhering to the conveyor device. The conveying device can be a single endless conveyor or instead consist of two or more sub-conveyors with a mesh size gradually decreasing from one to the next, which extend from the feed line for the liquid laden with solids to the brush device.

The brush device is usually a rotary brush although a reciprocating brush device can be used if desired »The brush device preferably has a bristle head, although a felt or other brush head instead Material, for example plastic fibers, can be used can"

The free mesh size of the conveyor is determined by the

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Required degree of 'solids removal and the type of liquid treated and the liquid contained therein Solids Determined »The liquid passes through openings in the conveyor and leaves the solids on the Top of the conveyor back.

The air storm serves to reduce the inclination of the liquid, to adhere to the meshes of the conveyor under capillary action, to reduce. The formation of a capillary film in the mesh of the conveyor would hinder an easy drainage of the liquid through the conveyor. aside from that the air can have a drying effect, and through Appropriate guidance of the air can also lift off the solid particles be conveyed at the end of the conveyor in the area of the brush device.

In some cases it may be desirable to form the top of the conveyor in the shape of a chute because of this can facilitate the separation of solids and liquids. As mentioned above, the solids of The solids removed in this way can be made available for further use in the conveyor by the brush device collected in a separate container or transferred to another conveyor. According to the invention they can can also be fed to another device, which is also

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if it has an open-mesh conveyor, its However, the mesh size is smaller than that of the previous one.

The air is fed into the device by suitable means, for example a motor-driven fan, introduced. The speed of the air flow is directed depending on the mesh size and the estimated total weight of the solids to be removed

Preferably the solids-laden liquid is applied to the conveyor using a spreader. This spreading device can, for example be a slot of great longitudinal extent that a substantially uniform and controlled loading of the conveyor enabled the solids with the liquid can be aimed at the conveyor at any angle, and the conveyor can suitably be so be designed that the solids in a central Channel that forms part of the conveyor *

The conveyor can be driven mechanically, electrically or electromechanically. Typically the Conveyor from an electric motor with a suitable reduction gear driven by a system of rollers. Usually the conveyor is metallic, but a plastic conveyor can be used may be used in certain circumstances · The

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as parts of the device according to the invention serving lines can also either made of metal or of Made of plastic "

In a preferred embodiment of the invention, the method can comprise the following method steps: The " Waste water is partially aerated by mechanical agitation in a day receiving tank, from the receiving tank the wastewater is fed to a coarse separator and the liquid that has been pretreated in this way becomes an annular basin supplied, in which the liquid is further aerated, the liquid is in the ring basin via a distribution tank It is turned over by several biological filters arranged over segments of the ring basin and falls off the latter under the action of gravity back into the ring basin, the liquid from the distribution tank is fed intermittently to an electrolytic flotation tank in which the suspended solids are separated and returned to the receiving tank while the purified liquid is withdrawn from the flotation tank becomes β

Similarly, a special embodiment of the device according to the invention comprises the following parts: A day receptacle with a screw agitator

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for stirring the wastewater contained therein, a device for drawing off the wastewater from this and for feeding it into a coarse material separator, an inlet, direction for feeding the liquid from the latter into an annular aeration tank with a Blade aerator (paddle) for aerating the liquid is equipped, a device for circulating the liquid by arranged above the ventilation container biological Filter back to the aeration tank and a facility for removing the liquid from the ventilation container and for feeding it into an electrolytic one Flotation tank for separating the suspended solids from the liquid and an outlet on the flotation tank for the outlet of the cleaned liquid.

In the drawing is a preferred embodiment the invention shown for example

Fig. 1 is a perspective view of a building for housing the device according to the invention;

FIG. 2 is a section through the building according to FIG. 1 to illustrate various parts of the device;

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Figure 3 is a top plan view of the ring basin and containers of Figure 2;

FIG. 4 is a plan view of a modified embodiment of the ring basin according to FIG. 3;

FIG. 5 is a perspective view of the ring basin of FIG. 3;

Fig. 6 shows the day receptacle according to Fig. 2;

Fig. 7 is an enlarged view of one of the _v solution in F. Containers shown in Figures 2 and 3;

FIG. 8 shows a supporting platform for the electrolytic settling basin and the upper part of the distribution container according to FIG. 2j

Figure 9 is a detailed illustration of the upper distribution tank;

Fig. 10 to 12 are different representations of the biological " see filters according to FIG. 2; and

Fig. 13 is an illustration of the separation device coarse solids from wastewater,

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Pig. 1 according shows the outside ■ a building for housing the device of the invention ") The building is k of polygonal outline having, for example 6, 8 or 10 pages and a corresponding number 6. of the roof portions, if desired, the building could have a generally circular or have any other plan shape. Are in one or more of the pages h entrance doors 8 with steps 10 provided, the diameter of the building 2 is preferably about 4.9 πι (16 feet) and the height of the sides is preferably about k ₀ 3 m (10 feet).

A ring container 12 (FIG. 2) with an inner and an outer wall runs around the inner outline of the building 2. This container is continuous, watertight and open at the top and forms a ring basin. Above this Ring basin 12 are located on this supported biological filter 14. These can be around the entire inner contour of the building or over part of it

Inward of the ring basin 12 are water tanks T1 and T2i which contain filter batteries (banks filters). In the middle of the building 2, below the floor level, a day- receiving container 6 is installed. The container 16 can be of circular or similar construction and its depth corresponds to the daily load

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a Einweichgrube (macerator Pit) vary ,, The daily receptacle 16 is preferably made of a metal structure that is completely prefabricated with a motor driven mixer "The depth of the waste water in the ^l tank 16 is controlled by level sensor or level probe 18 and suitable electrical switch. The container 16 is covered with a lid made of perforated metal which is formed in two halves.

Between the two water tanks T1 and T2 there is an electrolytic flotation tank at a high level 18, and at an even higher level is a distribution container 20, which is attached to the hanging Filter 14 leads.

The flotation tank 18 is equipped with level sensors '22 or equipped with a float switch that controls the liquid level in the container 18 controls · The probes 22 or the float switch switch corresponding pumping devices on or off, the liquid is pumped into the container 20, from which it is pumped through electrically controlled, motor-operated valves V1 is passed into the container 18- "

Electrodes 136 and 38 are also in container 18 arranged, which generate a multitude of small gas bubbles,

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which rise to the surface of the liquid in the container «. As the bubbles rise, they take _{Q away the floating impurities}

Located on a part of the circular ring basin 12 a rotor 20, which the wastewater or the slurry in the basin 12 ventilated "In a modified arrangement A surface or swimming aerator can be used for the aeration basin be used.

The wastewater or slurry enters the day receiving container 16 from cattle breeding facilities or from a soaking pit and can flow into the day receiving container 16 intermittently or continuously. A screw agitator 2.6 in the day receiving it stirs the wastewater and keeps solids in suspension. At predetermined time intervals, a portion of the wastewater is removed by means of a pump P1 and pumped to a fiber remover 28. It is highly desirable to completely remove fibers, hair, straw and other materials so that they do not cause clogging in the subsequent part of the treatment. This is taken care of by the fiber remover, which is described separately. The removed fibers can then be transported outside of the building 12, while the liquid flows back through a pipe 29 into the annular basin 12. When this program phase is finished, will

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the pump P1 stopped. In a similar way, the waste water level in the annular basin is maintained by means of a float valve or by means of level sensors 30 or through an overflow pipe which leads into the day receptacle 16

a
ventilated and circulated by means of the rotor 26, which is driven at intervals or continuously by means of a motor 32. The time cycle can be predetermined from the BOD level of the wastewater. A pump P2 pumps liquid, either intermittently or continuously, into the distribution _{container 20 0} located above. The container 20 enables an even distribution of the liquid to the hanging filters 15 »As shown in FIG filters 14 lead "the number of hanging filter 14 depends on the amount and density of the waste water from _o A more detailed description of the method and use of the hanging filter follows.

The waste water from the hanging filters 14 is returned to the king basin 12 . The system consisting of the pump P2 and the rotor is operated either continuously or on a time basis. When the motorized valve V1 is opened, the waste water, instead of flowing through the lines 33 to the hanging filters 14, becomes the container

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removed, and into the electrolytic flotation tank 18 led immediately below. The amount of liquid withdrawn is determined when the unit is designed and by means of a level sensor 22 or by means of an overflow pipe leading to the day receptacle 16 controlled. The level sensor or the time control or the float valve actuates relays and gives a period of time for the removal of the floating foam and also closes the motor valve V1, so that from the ring basin or the aeration tank the lines 33 and can flow over the hanging filters "

The electrolyte tank 18, which is used as a gas flotation and Separation unit can be viewed is with. Electrodes 36 and 38 equipped with the low DC voltage operated and an electrolytic flotation process and the separation of suspended solids in the mentioned manner bring about * The electrodes can be separated by insulating spacers and on insulated Be mounted supports that are supported on the bottom of the pool. For the flotation process is a with Draft fixed interval available, and the treated wastewater is then from a nozzle above the Sieves 36, 38 executed. This is done mechanically Pumping by means of pump P3. The action of the pump is operated by one when the fluid level is low

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Level sensor 22 or a float valve in the electrolyte basin 18 is interrupted, and the pump P3 also works as a barrier to the continued flow of treated wastewater. Instead, the sewage can be continuous can be introduced into the electrolyte pool, and the sludge can be scraped off at intervals.

An electrically controlled motor valve V2 is then opened by a program control and allows the sludge or foam floating above to be returned to the day receiving container 16 via a vertical downpipe 37. The program control then closes valve V2. A similar valve V3 is then opened and the sludge at the bottom of the electrolytic sieve basin is directed into a sludge dewatering tank 2k . The sludge is discharged at a suitable point outside the building via a motorized valve V5, while the excess liquid is returned to the day receptacle 16 via a check valve (one-way valve) V6 and a downpipe 37.

The process is then repeated at predetermined intervals. The coming into the electrolyte pool 18 Water is sent through a circulating distributor device to break up the remaining sludge, which has settled at the bottom of the pool. The water

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collects and finally flows over a vertical one Main overflow pipe downwards · Instead of this, with continuous operation, the waste water or the sludge can flow into near the top of the container and through the electrolyte screen down and out of the container bottom pour out.

The sludge is periodically removed by mechanical screeding eliminated

After removal from the electrolyte basin by means of the pump P3, the water becomes the bottom of the reservoir A pumped into the container T2. The container T2 has a clarifying device, and the water is caused to flow through it to flow upwards, leaving any residual solids up put down on the ground ,, Since the pump P3 works continuously, the existing contents of the storage container are diluted by the water flowing up through the clarifier flows into the container B, which is of the same design, and there is a dilution,

An electrically controlled motorized valve V ^ and a pipe system admit water as required in order to maintain the desired liquid level in the day receiving container. This is controlled by a pe gel-dependent switch.

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The effect of this water on the incoming wastewater is that it has a biological (aerobic) effect is initiated because it has a high oxygen content after the electrolytic sieving treatment, and is so designed to avoid any septic sewage conditions and seasonal throughput fluctuations as well as changes as a result of discontinuous or irregular Take storage densities into account " The water is then drawn from the surface of a reservoir B and a second clarifier T2 Cascade-like fed and then through further filter devices, such as sand or activated carbon filters passed through. These facilities are additional facilities and depend on the standard requirements for the outgoing End product.

The following additional equipment is required for certain applications:

(a) Soaking chests when large amounts of fibrous material enter the system;

(b) A sand or »gravel trap , especially when treating poultry manure; ^v

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(c) Recovery facilities can be provided to lower copper and other metals that impair or prevent biological (aerobic) digestion through the application of electric current

to
Remove tension «)

The system is designed so that it can be easily adjusted according to the throughput of the unit in size and processing capacity can vary, It can be seen that the system is sufficient for all types of organic waste.

For frost protection can be through one in the roof of the building housed thermostats are provided, the continuous circulation by pumps to prevent the Freezing caused

This system is designed for the recognized dry weather attack and it can be built in a flood level sensor can be provided, which accelerates the entire sequence of operations and allows the throughput through the system to accelerate «If the water level falls below the flood level sensor, the system reverses back to the predetermined sequence of activities »

The whole system can preferably be electrical

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Devices, program controls, contactors, contactors and level sensors can be controlled »Furthermore, a control panel can be used with visual display of the sequence of activities through color light displays »

Further modifications of the system and a combination of systems could be equipped with a double king basin and double filter batteries. Depending on the conditions and size of the unit, this system or any multiplication of this system or any combination of such systems could be used and incorporated _o The effective use of the biological filters depends on the growth of bacteria or other organisms on plates contained in the filter ο As the liquid trickles over the filter surfaces, bacteria and other microorganisms that grow as a muddy film on the surface of the media feed on the organic contaminants and remove them ο This principle is used in numerous wastewater treatment processes, whereby the sludge grows on a bed of sorted natural stone, such as gravel, or another inert medium. The filters 14 (particularly Figures 10-12) are made using corrugated plastic sheets which are divided by strips of wood or other material and which provide an effective inert medium for the film to be grown thereon. In some cases

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For example, flat plates as well as a variety of other types of spacer members can be used. Thickness and

-en

was the wooden slats limited hours the uniform distances between the plastic sheets and ensure an extremely favorable nutrient growth floors _o

Effective distribution of the wastewater can be through an unstable tilting trough or similar device at the top of each filter, using the two sides of the filter batteries alternately charged with a torrent. The plastic material or other material is preferably transparent or translucent, so that it is transparent to natural sunlight, but any plastic material will suffice, which is suitable as a base for biological growth. Each filter set is in a metal frame added, and a splash barrier is attached to the top.

There is an openwork at the top of each filter Sieve arranged to hold back any large suspended particles contained in the incoming wastewater Adjustment means available for the central spindle on which the tilting trough is mounted and also the two stop buffers on both sides of the trough are adjustable so that

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an adequate compensation for an uneven installation the basis is given.

The filters can be hung from a structure or carried on cross members or placed directly above any other suitable Wise drained area to be set up. The effective growth of bacteria also contributes to its effectiveness on the wooden strips as well as the fact that both sides of the plates are in the filters for the growth of Bacteria are available «

The preferred device for carrying out the method and the device according to the invention for removing straw, grass and similar fiber materials from the wastewater is described in the parallel application by the same applicant on the same day. The device is shown in FIG. 13 and has an endless conveyor which is mounted on conveyor roller surfaces 64 and 66 and guided around them. The conveyor 62 is an open-mesh conveyor. The roller 66 of the conveyor is driven by a motor with gearbox 68 via a belt drive 70.

The device has a conduit 72 for introducing the liquid laden with solids onto the surface of the conveyor 62 on, in an area passing through

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Arrows Jk is identified, the majority of the zoom out liquid passes through the openings of the conveyor to a discharge line 76 "through which it is discharged _e The liquid from the discharge line 76 can be directed back into the circulation so that it absorbs more solids and finally again is guided through line 72 to the conveyor »

A motorized fan 78 conveys air a conduit 80 that sends an air jet onto the solids directed loaded liquid onto the conveyor 62. The air flow under suitable pressure reduces the tendency of the liquid, in the mesh of the conveyor

also has a drying effect on the solids on the conveyor. "The air finally flows through the conveyor and can escape to the atmosphere." By suitable guidance, the air can pass through the conveyor at 82, then to the bottom surface of the upper one Runs of the conveyor continue to flow in parallel and finally pass upwards again through the upper run of the conveyor 62 at Bk , so that they lift solid particles *, for example straw and grass, resting on the conveyor 62 from the conveyor work to be performed facilitated or * reduced

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The brush device 86 is from a motor through a mechanical drive ° 0-driven brush device 86 has a bristle head 88, and the bristles are arranged such that they thereof in contact with the exit end of the conveying run of the run-on roller 6k are _e the Bristles 88 sweep the pest off the conveyor, possibly in a separate waste bin

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Claims (1)

Claims ^ A method for purifying wastewater, characterized in that coarse solids are removed from the wastewater; that the withdrawn liquid is fed to at least one ventilation container, that the liquid from the ventilation container is fed through at least one
biological filter back into at least one
Aeration tank is circulated; and that the in
suspended solids contained in the liquid withdrawn from the ventilation tank by electrolytic
Flotation can be separated. 2. The method according to claim 1, characterized in that the liquid from the at least one ventilation container is fed to several filters • via a distribution container » 3β Method according to claim 2, characterized in that the solid suspended matter from the liquid withdrawn from the aeration tank or tanks
be eliminated by removing this liquid from the
Distribution tank is returned to an electrolytic flotation tank _e - 27 - 2 (19861/0753 k " Method according to one of the preceding claims, characterized in that the liquid in the at least one ventilation container is mechanically aerated. 5 © Method according to claim k, characterized in that the liquid is aerated in an annular ventilation container by a paddle wheel _e 6. The method according to any one of claims 1 to 3 »characterized in that the liquid in the ventilation container or the ventilation containers by one or several surface aerators are ventilated. 7β method according to one of the preceding claims, characterized in that the circulation of the liquid through the filter or filters with the separation alternated by solids from this 8β Method according to one of claims 1 to 71 thereby characterized in that the liquid from the ventilation tank for the separation of the suspended solids is continuously withdrawn to an extent that is essentially equal to the inflow of liquid to the at least one aeration tank, - 28 - 209851/0753 9. The method according to any one of claims 1 to 7, characterized in that the liquid from the ventilation container for the separation of the suspended solids is deducted at predetermined time intervals. 10. The method according to claim 9t, characterized in that the steps of Uttiwälzens the liquid and the separation of solid suspended matter are carried out in a time cycle " β Method according to one of the preceding claims, characterized marked that the wastewater is supplied from a day receptacle » 12. The method according to claim 11, characterized in that that the waste water is partially mechanically aerated in the receptacle. 13. The method according to claim 12, characterized in that that the waste water in the receptacle is partially aerated by a screw agitator. 14. The method according to any one of claims 11 to 13, characterized characterized in that the receptacle is filled up from a canning pit at predetermined time intervals will, -29- 209851/0753 15 · The method according to any one of claims 11 to 14, characterized characterized in that at least a portion of the solid suspended matter after separation of the same from the Ventilation tank or peeled off the ventilation tanks Liquid returned to the waste water intake becomes β 16. The method according to claim 15 »characterized in that part of the suspended solids separated by flotation is removed through an overflow pipe and a other part of the suspended solids on the ground, an electrolytic flotation tank sinks and from there via a sludge settling basin " 17 «Method according to one of the preceding claims, characterized characterized in that the liquid from the settling basin before exiting through one or more clarification tanks is passed through " Method according to claim 17 »characterized in that that the clarifier or clarifiers have Banks filters (filter batteries). 19, method according to claim 18, characterized in that the liquid is passed through one or more silica sand filters at the end of the filter batteries .. - 30 - 2098S1 / 0753 20ο Method according to one of claims 17 to 19 »thereby characterized in that the purified liquid is finally in one or more activated carbon filters is cleaned afterwards, ο A method for cleaning wastewater, characterized in that the wastewater is partially aerated in a day receiving container by mechanical cooling, the wastewater is drawn from the receiving container in a coarse separator, the liquid thus obtained is ^{fed to an annular basin 1} , in which the liquid continues is aerated, the liquid in the ring basin is circulated through a distribution container and through several biological filters which are arranged above the segments of the ring basin, so that the liquid then falls back into the ring basin under the action of gravity, the liquid from the distribution container intermittently is diverted into an electrolytic flotation tank, in which the suspended solids are separated and returned to the receiving tank, and the cleaned liquid is discharged from the flotation tank. 22. Device for performing the method according to - 31 - 209851/0753 one of the preceding claims, characterized by a waste water receiving container, a coarse material separator, one or more ventilation tanks, one or more biological filters, a device for Separation of solid suspended matter from the liquid withdrawn from the ventilation container by electrolytic means Flotation and a device for passing the wastewater through each of said units, 23. The device according to claim 22, characterized in that that the aeration tank or tanks have one or more surface aerators, Zk ₀ device according to claim 22, characterized by an aeration tank of annular design with a paddle wheel for aerating the liquid, 25 »Device according to one of claims 22 to 24, characterized characterized in that the device for conveying the Liquid comprises one or more pumps arranged between the units, 26 "Device according to one of claims 22 to 25, characterized by a day receptacle from which the wastewater is sucked, - 32 - 209851/0753 27. Device according to claim 26, characterized in that the receiving container is arranged below the level of the ventilation container ₀ 28, device according to claim 26, or 271, characterized in that that the receptacle has a screw agitator for stirring the wastewater contained therein. 29 · Device according to one of claims 22 to 28, characterized through a distribution tank for distributing the liquid from the aeration tank or the Ventilation containers to multiple filters 30. Device according to one of claims 22 to 29 »characterized in that the solid suspended matter from the the liquid removed from the aeration tank or tanks in an electrolytic Flotation tanks are separated. 31 »Device according to claim 30, characterized by means for recycling at least a portion of the separated solids from the electrolytic Flotation tank for waste water intake nozzle 32 «Device according to claim 30 or 31 * by means of a device for guiding the liquid from the distribution tank into the electrolytic flotation tank » - 33 - ■ ? 09 £ S1 / G753 33 device according to one of claims 22 to 33, characterized in that the coarse material separator comprises the following parts: an open-mesh conveyor, a conduit means for supplying liquid mii solids on the conveyor, an air supply device located behind the duct device for feeding an air stream on the liquid with the solids on the conveyor, and a brush device behind the Air supply device for brushing off the conveyor adhering solids treated with air. 3k. Apparatus according to Claim 33, characterized in that the conveyor device is a single endless conveyor _e 35 · Device according to claim 33 »characterized in that that the conveying device has two or more sub-conveyors, which one behind the other from the line device for the liquid with the solids to extend the brush device and have progressively decreasing mesh sizes in this direction. 36, device according to one of claims 33 to 35 »thereby characterized in that the brush device has a rotating Brush is » 209851/0753 37ο device according to one of claims 22 to 36 ». characterized by one or more septic tanks arranged to be removed from the facility for the separation of solid suspended matter obtained purified liquid. Device for purifying waste water, marked through a day receptacle with a screw or screw agitator to stir the contained therein Sewage, a device for sucking in the sewage from this and for feeding it to a coarse material separator, a: means for feeding Liquid from this to an annular aeration tank with a paddle stirrer for aerating the Liquid, a device for circulating the liquid through biological filters arranged above the aeration tank back to the aeration tank and a device for conveying the liquid from the aeration tank into an electrolytic flotation tank for the separation of the suspended solids contained in the liquid and an outlet on the flotation tank for the purified liquid _β 209851/0753 Blank page