DE102017222807A1 - Process and device for the treatment of industrial wastewater - Google Patents

Abstract

The present invention relates to a process for the treatment of contaminated waters and waters, in particular industrial effluents,
in which a pollutant-contaminated water is added to at least one oxidizable precipitant which forms flocs in the water and adsorbs the pollutants,
in which the water containing pollutants and precipitants is aerated, so that air bubbles (16) rise in the water,
- In which by a non-impermeable to the flocculation filter device (12) purified water is removed.

Description

The present invention relates to a method and apparatus for treating contaminated waters or waters, such as industrial sewage, polluted surface waters and polluted groundwater.

Industrial wastewater, ie wastewater from industrial plants, may contain high levels of TOC, where TOC stands for "total organic carbon" and have a high COD, where COD stands for "chemical oxygen demand". Wastewater containing relatively high amounts of cyanides and / or arsenic as well as arsenic compounds, e.g. Arsenite and arsenates contain, for example, waste water from coking plants. Cyanides or nitriles are, above all, salts and other compounds of hydrocyanic acid. Arsenites are salts of arsenic acid. Arsenates are salts and other compounds of arsenic acid. In principle, surface waters and groundwaters can also be contaminated with such impurities as TOC and COD.

It has been found that conventional biological and / or chemical treatments of such contaminated waters, especially of industrial effluents, which have high levels of TOC and / or COD and in particular cyanides, are generally insufficient to match the parameters in question permissible concentrations to ultimately allow the treated effluents to be discharged into an unpolluted surface water, such as a lake, sea, stream or river.

The present invention therefore deals with the problem of providing an improved embodiment for a method and a device for treating polluted waters, preferably industrial effluents, which have improved cleaning action with respect to TOC and / or COD and in particular with regard to cyanides and / or or arsenic and arsenic compounds.

This problem is solved according to the invention by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea to combine an addition of an oxidizable precipitant to the contaminated water, aeration of the water with an oxygen-containing gas, preferably air, and a filtration of the water with each other. The precipitant forms flakes in the water, the surface of which serves to adsorb the contaminants contained in the contaminated water. In that regard, the precipitant is an adsorbent which has an adsorbent effect on the pollutants in question. Accordingly, an adsorbent precipitant or a precipitating adsorbent is preferably used here. The use of an oxidizable precipitant in conjunction with aeration leads to oxidation of the precipitant in the water. On the one hand, this causes the flakes that form to be chemically and / or mechanically stable. On the other hand, the ventilation also means that the forming flakes are smaller overall. This is due in particular to the movement generated by the aeration in the water. Smaller flakes have a larger surface area relative to the volume, so that a significantly larger surface area can be provided for adsorbing the pollutants with the aid of the smaller flakes. The filtration takes place by means of a filter device which separates a raw side from a clean side. The filter device is permeable to the water, but not to the floc of the precipitant. Since the pollutants in question are adsorbed by the precipitant flakes, with the filter device and the pollutants in question can be retained or filtered out. By means of filtration, the flakes laden with the pollutants can be retained on the raw side, while purified water can be removed on the clean side. The use of such a filter device is essential, since the small flakes settle only very slowly in the water. If the water is moved, it may also be the case that these small flakes do not settle or do not settle completely.

It has been found that the combination of oxidizable precipitating agent, aeration and filtration allows for a reduction in the levels of TOC and / or COD and in particular cyanides and arsenic and arsenic compounds below the allowed concentrations, so that the treated water withdrawn from the filter device will be the same respective unpolluted or clean surface waters can be supplied.

According to an advantageous embodiment, a pH correction agent can be added to the contaminated water, depending on its pH, so that a predetermined pH is established in the water. Depending on the contamination of the water and depending on the industrial plant, the industrial wastewater produced can be acidic or alkaline, so that a pH correction is required in order to ultimately be able to supply the waters to a preferably pH-neutral surface water.

Particularly advantageous is a development in which the pH correction agent and the precipitant are added to the water at the same time. The simultaneous addition of precipitant and pH correcting agent is advantageous in terms of Mixing with the water and simplifies the manufacture of the device.

In another advantageous embodiment, the aeration of the water is such that preferably form small flakes. Small flakes are flakes with an average particle size of not more than 1 mm, preferably of not more than 0.1 mm and in particular of not more than 0.01 mm. The aeration of the water can be carried out in different ways, which affects the size of the flakes. In particular, the ventilation can for example be such that at the same time there is an intensive mixing of the water with the precipitant or the pH correction agent.

Preferred is an embodiment in which the aeration of the water takes place simultaneously with or immediately after the addition of the precipitant. In this way, the achievable by means of aeration mixing and the oxidation and comminution of the flakes takes place at a very early stage, namely at the beginning of the here described treatment process. Thus, very much adsorption surface for the pollutants is available very early, which increases the efficiency of water purification.

Appropriately, the ventilation is fine bubbles. Due to the fine-bubble aeration, a large surface is also provided at the bubbles or bubbles relative to the volume, which is in contact with the water and accordingly is available for the release of oxygen. Thus, in a short time much oxygen can be introduced into the water to effect the desired oxidation of the precipitant. The fine-bubble aeration also supports the formation of small flocs of the precipitant. With such aeration bubbles or bubbles enter through openings or pores in the water. Bubbles of a fine-bubble aeration have at the outlet, for example, a diameter of not more than 3 mm and preferably not more than 2 mm and in particular not more than 1 mm. A fine-bubble aeration can be achieved, for example, by means of ventilation openings or pores, which have an opening cross section of at most 1 mm ² .

Particularly useful is an embodiment in which the ventilation is carried out for the mixing of water and precipitant. Thus, the ventilation is locally and temporally matched to the addition of the precipitant to achieve the most intensive mixing possible. Appropriately, the ventilation is therefore carried out in the water at the place of addition of the precipitant. On a separate or additional mixing device can thus be dispensed with, which reduces the cost of the device.

In an advantageous development, the filter device can have at least one filter element which has a filter body which can be flowed through from the outside to the inside. The separation of the raw side and the clean side realized with the aid of the filter device has the result that, in the case of a filter body which can be flowed through from the outside to the inside, the raw side is arranged on the outside, while the clean side is located inside the filter body. Accordingly, the respective filter body is designed so that the flakes are retained on the rohseitiger outside, while in the interior of the filter body at least a clean-side drain channel is formed, from which the purified water is discharged. For example, the purified water is particularly easy to extract from the respective drainage channel of the respective filter body. The flakes with pollutants adsorbed on them remain on the outside of the filter body. By using such, immersed in the contaminated water filter body, a relatively large volume of purified water can be vacuumed, which improves the usability of the process presented here for the purification of industrial wastewater and contaminated surface and groundwaters.

Appropriately, according to a development may be provided that the respective filter body is a ceramic filter body. In other words, the filter body is made of ceramic and in particular consists exclusively of ceramic. The use of a ceramic filter body is characterized by a high resistance to corrosion and resistance to a variety of chemical and / or biological substances. Accordingly, such a ceramic filter body has a particularly long life.

Suitably, the respective filter body may be a flat membrane. Such flat membranes are particularly suitable for forming stacks within the filter device in order to provide large-area outer sides on the outside, in order to be able to extract correspondingly large volume flows of purified water.

The filter body, preferably the ceramic filter body, can be designed as a microfilter with a pore size of at most 0.01 mm or as a nanofilter with a pore size of not more than 0.001 mm. Thus, even small and smallest flakes can be efficiently retained.

According to an advantageous embodiment, the process is carried out discontinuously, so that at least one tank of a water treatment plant is filled with contaminated water and precipitant, the ventilation is performed and the purified water through the Filter device is removed from the basin before the basin is filled again with contaminated water. Such a discontinuous process may also be referred to as a batch process. At the end of such a batch run, the sludge accumulating in the pool can be removed before a new batch run. The sludge largely consists of the flakes of the precipitant with pollutants adsorbed thereon.

Alternatively, the process can also be carried out continuously so that permanently contaminated water is supplied and purified water is removed.

Advantageously, the ventilation takes place in a ventilation area, while the filtration takes place in a filtration area. Ventilation area and filtration area are spaced apart spatially according to an advantageous embodiment, so that the filter device is not or not directly exposed to the ventilation air bubbles. In this way the functional separation of aeration and filtration is ensured.

According to a further development, a sedimentation section can be provided which leads from the aeration area to the filtration area and in which sedimentation of at least part of the flakes takes place. With the aid of such a sedimentation section, at least part of the flakes can be deposited along the sedimentation section in order to reduce the loading of the filter device.

Advantageously, the sedimentation section may comprise a sedimentation basin, which is arranged between an aeration basin containing the aeration area and a filtration basin containing the filtration area. As a result, the three functions of aeration, sedimentation and filtration are realized in three separate basins, which increases the efficiency of the process.

Alternatively, it is also possible to arrange the ventilation area and the filtration area in a common pool, which reduces the cost of implementing a corresponding water treatment plant. If available, then the sedimentation path is arranged in this common basin.

According to an advantageous embodiment, the sedimentation section may have an overflow weir which is arranged in the common basin between the aeration area and the functional area. With the help of such an overflow we achieve that flakes that have already dropped below an overflow edge of the overflow weir no longer reach the filtration area. As a result, the sedimentation can be improved on a side of the common basin facing the ventilation area.

In another development, the common basin may be configured as a circulating tank circulating in an annular manner, in which the sedimentation path leads from the ventilation area to the filtration area.

Suitably, the circulating tank outside the sedimentation between the ventilation area and the filtration area may have a partition. With the help of this partition wall, the water is forced to follow from the ventilation area of the sedimentation route to reach the filtration area. A bypass of the sedimentation is prevented by the partition.

Additionally or alternatively, a conveyor for driving the water along the sedimentation can be arranged in the circulation tank. This conveyor forces a flow in the circulation tank with a predetermined flow direction, which leads from the ventilation area along the sedimentation to the filtration area. In this case, the partition mentioned above can be dispensed with.

A device according to the invention is formed by a water treatment plant which serves for the treatment of contaminated waters or waters, in particular of industrial wastewaters, surface waters and groundwaters. This water treatment plant comprises at least one tank, a feed for supplying contaminated water, a drain for discharging purified water, an adding device for adding the precipitant to the water, a venting device for aerating the water, a filter device and a control device for controlling the controllable components of the water water treatment plant. The control device is used in particular for controlling the feed device and the ventilation device. Furthermore, the control device is expediently configured or programmed such that it operates the water treatment plant according to the method described above.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

• 1 ein Flussdiagramm zur Veranschaulichung eines Verfahrens zum Aufbereiten von verunreinigten Wässern,
• 2 eine stark vereinfachte Schnittansicht einer Wasseraufbereitungsanlage für ein diskontinuierliches Verfahren,
• 3-5 jeweils eine stark vereinfachte Schnittansicht der Wasseraufbereitungsanlage für ein kontinuierliches Verfahren, bei verschiedenen Ausführungsformen,
• 6 und 7 jeweils eine stark vereinfachte Draufsicht auf die Wasseraufbereitungsanlage für das kontinuierliche Verfahren, jedoch bei weiteren Ausführungsformen.

Show, in each case schematically,

• 1 a flow chart illustrating a method for treating contaminated waters,
• 2 a highly simplified sectional view of a water treatment plant for a batch process,
• 3-5 each a highly simplified sectional view of the water treatment plant for a continuous process, in various embodiments,
• 6 and 7 in each case a greatly simplified plan view of the water treatment plant for the continuous process, but in other embodiments.

Hereinafter, with reference to the figures, a preferred application of the invention will be discussed, which relates to the treatment of industrial wastewater. Other important applications of the invention relate to the treatment of contaminated surface waters and groundwaters. The explanations of, for example, the industrial effluents can be analogously transferred to the examples of surface waters and groundwaters. In particular, only the term "wastewater" used below is to be replaced by the term "water".

Corresponding 1 can an industrial plant 1 , which is, for example, a foundry or coking plant, with a wastewater treatment plant 2 Be equipped to handle industrial wastewater while operating the industrial plant 1 arise, treat them to a clean or unpolluted surface water 3 , for example, a lake or river, to be able to supply. Unpurified wastewater is in 1 through an arrow 4 marked by the industrial plant 1 to the wastewater treatment plant 2 leads.

Purified wastewater is by an arrow 5 indicated by the sewage treatment plant 2 to the surface waters 3 leads. The unpurified wastewater 4 Contains pollutants, such as cyanides and / or arsenic or arsenic compounds, the proportion of which must be lowered below a prescribed limit before it as purified wastewater 5 the surface water 3 is supplied.

The processing plant 2 includes at least one pelvis 6 and has an inlet 7 for supplying polluted wastewater 4 as well as a process 8th for discharging purified wastewater 5 on. With the help of an addition device 9 At least one oxidizable, for the pollutants in question adsorbing precipitant, such as an iron salt, can be supplied to the wastewater. An admixing device 10 allows the addition of at least one pH correcting agent to the wastewater. A ventilation device 11 allows venting of wastewater mixed with precipitant and optionally with pH correction agent. A filter device 12 causes a filtration of the waste water, the filter device 12 permeable to treated wastewater while impermeable to the precipitant. The adsorbed by the precipitant pollutants are thereby from the filter device 12 also withheld.

The processing plant 2 is also with a pump 13 equipped to clean the sewage 5 through the filter device 12 from the respective basin 6 suck. The processing plant 2 is also with a controller 14 equipped in a suitable manner, for example via control lines 15 with controllable components of the plant 2 is coupled, for example with the feed device 9 , the mixing device 10 , the ventilation device 11 and the pump 13 , The control device 14 thus serves to control the plant 2 , For this purpose, the control device 14 programmed or configured so that they are the treatment plant 2 can operate to carry out the method described in detail below for the treatment of industrial wastewater. The following description of this treatment process also includes advantageous embodiments for the treatment plant 2 ,

According to the 1 to 7 For example, the treatment process comprises at least steps A: adding at least one oxidizable precipitant to the pollutant-contaminated effluent 4 , B: aerating the pollutant and precipitant containing wastewater with an oxygen-containing gas, preferably with air, in such a way that bubbles rise in the wastewater, which in the 2 to 7 indicated and designated 16. As a further step C: the method comprises filtering the waste water, so that by the filter device 12 the purified wastewater 5 can be dissipated.

The wastewater to be purified here has comparatively high values for TOC and / or COD. In particular, the wastewater can also have relatively high values for cyanides and / or arsenic as well as for cyanide or arsenic compounds. Pollutants in this context are thus in particular TOC and cyanides or arsenic and their compounds as well as all substances that produce COD. The precipitant is oxidizable and forms flakes in the waste water, which have an adsorbent effect on the pollutants. The ventilation ensures that the precipitant oxidizes. The oxidation of the precipitant causes chemically and mechanically stable flakes and favors the formation of small flakes. The filter device 12 is configured to be impermeable to the flakes and thus to the contaminants attached thereto or adsorbed thereto.

By means of the metering device 10 can the polluted wastewater 4 depending on its pH, a suitable pH correcting agent may be added. The addition of the pH correction agent takes place by means of the control device 14 controlled, namely such that adjusts a predetermined pH in the wastewater. Preferably, a neutral pH is desired. The addition of the precipitant is in the 2 to 7 through arrows 17 indicated. In the following, the precipitant can also be denoted by 17. The addition of the pH correcting agent is in the 2 to 7 through arrows 18 indicated. In the following, the pH correction agent can also be designated by 18. Appropriately, the addition of the pH correcting agent 18 and the precipitating agent 17 to wastewater at the same time. In the examples of 2 and 4 to 7 is even a common feed 7 for untreated wastewater 4 , Precipitant 17 and pH correction means 18 are provided. In the example of 3 are separate feeds 7 . 7 ' and 7 " for untreated wastewater 4 , Precipitant 17 and pH correction means 18 are provided.

The aeration of the wastewater is specifically carried out so that the smallest possible flakes of the precipitated precipitate form in the wastewater. Small flakes have a grain size of a maximum of 1 mm. However, very small flakes with grain sizes of not more than 0.1 mm and smallest flakes with grain sizes of not more than 0.01 mm are preferred. In order to be able to produce such small or very small and smallest flakes, the aeration of the waste water can substantially simultaneously or immediately after the addition of the precipitant 17 respectively. For this purpose, in the embodiments of the 2 to 7 the ventilation device 11 placed proximal to the site at which the addition of the precipitant 17 to the wastewater 4 he follows. Furthermore, the ventilation is advantageously carried out fine bubbles, so that as many as small as possible bubbles in the wastewater 4 rising up. This leads to an intensive mixing of the precipitant 17 and optionally the pH correcting agent 18 with the wastewater to be purified 4 , On the other hand, comparatively high amounts of oxygen can be added to the wastewater via the large number of small and very small bubbles 4 or the precipitant 17 be delivered. This supports the oxidation of the precipitant 17 , Small bubbles have a diameter of a maximum of 3 mm, preferably of at most 2 mm and in particular of a maximum of 1 mm. The venting is expediently carried out in conjunction with an injection of air or a suitable other, oxygen-containing gas, wherein the supplied gas stream exits through pores or openings of a ventilation body and enters directly into the wastewater. Purely exemplary is in 2 a pump 19 represented, with the aid of which a corresponding gas stream, preferably an air stream, a porous body 20 the ventilation device 11 can be fed. Through the pores or openings of the body 20 small and smallest gas bubbles emerge from the body 20 out and get into the sewage. The pores or openings have, for example, an opening cross-section of not more than 1 mm ² .

The ventilation device is expedient 11 positioned and designed so that it produces an intensive mixing of wastewater and precipitant and optionally pH correcting agent. In the embodiments shown here can thus be dispensed with an additional, separate mixing device. The processing plant presented here 2 is characterized in particular by the fact that between inlet 7 and expiration 8th can be dispensed with a mixing device.

In 2 is also representative of all embodiments shown here shown that the filter device 12 at least one filter element 21 having, which can be flowed through from the outside to the inside filter body 22 has. This filter body 22 thus has a raw side outside 23 which is impermeable to the precipitate of the precipitant. Inside contains the filter body 22 at least one clean-side drainage channel 24 from which the purified wastewater can be discharged. Accordingly, the process is 8th so to the respective filter body 22 connected that he with the internal drainage channel 24 is fluidically connected. In the example of 3 are purely exemplary three parallel flow channels 24 indicated that communicate with each other and the process 8th are connected. The filter body 22 is preferably a ceramic filter body and in particular configured as a flat membrane. The filter body 22 has, for example, an average pore size of not more than 0.01 mm for microfiltration and in particular of not more than 0.001 mm for nanofiltration.

At the in 2 In the embodiment shown, the treatment process is carried out discontinuously. Accordingly, basically only one basin 6 required, the polluted wastewater 4 , Precipitant 17 and optionally pH correcting agents 18 be fed, in which the ventilation is carried out and the purified wastewater 5 through the filter device 12 the pelvis 6 is taken out before the pelvis 6 again with contaminated water 4 is filled. It is clear that the treatment plant 2 several such pools 6 may have, in each of which the treatment process is carried out batchwise. It is also clear that after removing the purified wastewater 5 and before filling the basin 6 with new unpurified wastewater 4 that of the filter device 12 in the basin 6 retained impurities, mainly a sludge from the flakes of the precipitant, from the basin 6 be removed. For example, the pelvis 6 and the filter device 12 be cleaned in a suitable manner.

In contrast to 2 show the 3 to 7 Embodiments in which the treatment process is carried out continuously. The continuous process is permanently polluted wastewater 4 is fed and permanently purified wastewater 5 dissipated. Likewise, the addition of precipitant done 17 and optionally the addition of pH correcting agent 18 and the ventilation functional permanently. Unless the filter device 12 only a single filter element 21 has, the filtration, so that discharge of purified wastewater 5 occasionally be interrupted to the filter element 21 to clean. This can be done, for example, by a brief backwashing of the filter element 21 with purified wastewater 5 respectively. Unless the filter device 12 several filter elements 21 , these can be appropriately interconnected so that even during backwashing at least one filter element 21 at least one further filter element 21 can be operated for filtration, so that permanently purified wastewater 5 can be dissipated.

At the in 2 shown attachment 2 are a ventilation area 25 , in which the ventilation takes place, and a filtration area 26 , in which the filtration takes place, arranged close to each other or proximal to each other. The result is the filter device 12 the bubbles 16 more or less exposed directly. However, this plays no role in the batch process, since the filtration takes place after the aeration.

In the embodiments of the 2 to 7 are however said ventilation area 25 and said filtration area 26 spatially spaced from each other, so distally arranged to each other, in such a way that the filter device 12 the bubbles 16 not or not directly exposed. This simplifies the implementation of the continuous process. Furthermore, in these embodiments, a sedimentation path 27 provided, the one indicated by arrows current 28 the waste water from the ventilation area 25 to the filtration area 26 leads. In this sedimentation route 27 a sedimentation of at least part of the flakes takes place. Thus, some of the flakes collect along the sedimentation route 27 and does not get to the filtration area 26 What the loading of the filter device 12 reduced with flakes. Accordingly, time intervals between two successive regeneration processes or cleaning operations of the filter device 12 or the respective filter element 21 be enlarged.

According to 3 can the sedimentation route 27 a sedimentation basin 29 in which the main part of the sedimentation takes place. The sedimentation basin 29 is between an aeration basin 30 in which the ventilation area 25 located, and a filtration basin 31 arranged in which the filtration area 26 located. The individual pools 29 . 30 . 31 are through appropriate connecting lines 32 connected with each other. The provision of separate pools 29 . 30 . 31 for the individual functional areas 25 . 26 . 27 , simplifies the maintenance and cleaning of separate pools 29 . 30 . 31 and its components.

In contrast, the show 4 to 7 Embodiments in which a common pool 33 for ventilation area 25 , Filtration area 26 and sedimentation route 27 is provided. This can in particular the structural complexity for the realization of the system 2 to reduce.

In the example of 4 has the sedimentation route 27 an overflow weir 34 on, in the common pool 33 between the ventilation area 25 and the filtration area 26 is arranged. An overflow edge 35 the overflow weir 34 is in the common pool 33 positioned so high that a substantial proportion of the flakes has already sedimented so far that the wastewater, which is the overflow weir 34 can flow over, only contains a significantly reduced proportion of flakes.

In the example of 5 is in the common pool 33 instead of an overflow weir 34 an underflow weir 36 included, this is proximal to the inlet 7 is arranged and the mixture of unpurified wastewater 4 , Precipitant 17 and optionally pH correction means 18 to the ventilation area 25 feeds there to cause intense aeration and mixing for rapid oxidation of the precipitant and to produce the smallest possible flakes.

While in the examples of the 4 and 5 the common pool 33 is designed as a linear basin, show the 6 and 7 Examples where the common pelvis 33 is designed as a circular closed circulating circulation tank. In such a circulation tank leads the sedimentation route 27 in the direction of circulation of the ventilation area 25 to the filtration area 26 , This circulation direction is in the 6 and 7 indicated by an arrow and designated 37.

The designed as a circulation pool basin 33 indicates at the in 6 shown embodiment, a partition 38 on that outside the sedimentation route 28 between the ventilation area 25 and the filtration area 26 is arranged. The partition 38 prevents a bypass flow, which is opposite to the direction of rotation 37 directly from the ventilation area 25 to the filtration area 26 leads and thereby the sedimentation route 27 bypasses. In the example of 7 can on such a partition 38 be waived. In this example is in the common pool designed as a circulation pool 33 a conveyor 39 arranged to generate the flow 28 the wastewater in the direction of circulation 37 drives it, making it along the sedimentation route 27 flows. Wastewater in the filtration area 26 not from the common basin 33 is discharged, can flow in a circle and outside the sedimentation 27 in the direction of rotation 37 from the filtration area 26 back to the ventilation area 25 continue to flow.

Claims (21)

Process for the treatment of contaminated waters and waters, in particular industrial effluents, in which at least one oxidisable precipitant is added to a water polluted with pollutants, which forms flocs in the water and adsorbs the pollutants, in which the water containing pollutants and precipitants is aerated, so that air bubbles (16) rise in the water, - In which by a non-impermeable to the flocculation filter device (12) purified water is removed. Method according to Claim 1 , characterized in that a pH correction agent is added to the contaminated water depending on its pH, so that sets a predetermined pH in the water. Method according to Claim 2 , characterized in that the pH correcting agent and the precipitating agent are added to the water at the same time. Method according to one of Claims 1 to 3 , characterized in that the aeration of the water takes place so that preferably form small flakes. Method according to one of Claims 1 to 4 , characterized in that the aeration of the water takes place simultaneously with or immediately after the addition of the precipitant. Method according to one of Claims 1 to 5 , characterized in that the ventilation is fine bubbles. Method according to one of Claims 1 to 6 , characterized in that the aeration takes place for the mixing of water and precipitant. Method according to one of Claims 1 to 7 , characterized in that the filter device (12) has at least one filter element (21) having a filter body (22) through which can be flowed from the outside to the outside of which (33) the flakes are retained and in the interior of which at least one clean-side drainage channel (24) is formed, from which the purified water is discharged. Method according to Claim 8 , characterized in that the respective filter body (22) is a ceramic filter body. Method according to Claim 8 or 9 , characterized in that the respective filter body (22) is a flat membrane. Method according to one of Claims 1 to 10 , characterized in that the process is carried out discontinuously, so that at least one tank (6) of a water treatment plant (2) is filled with contaminated water and precipitant, the ventilation is performed and the purified water through the filter device (12) the basin (6 ) is removed before the basin (6) is filled again with contaminated water. Method according to one of Claims 1 to 10 , characterized in that the process is carried out continuously, so that permanently contaminated water supplied and purified water are discharged. Method according to one of Claims 1 to 12 Characterized in - that the ventilation carried out in a ventilation region (25), - that the filtration takes place in a filtration zone (26), - that ventilation region (25) and filtration area (26) are spatially spaced from each other, so that the filter device (12 ) is not or not directly exposed to the air bubbles (16). Method according to Claim 13 , characterized in that a sedimentation path (27) from the ventilation area (25) leads to the filtration area (26), in which a sedimentation of at least a portion of the flakes takes place. Method according to Claim 14 , characterized in that the sedimentation section (27) has a sedimentation basin (29) which is arranged between a ventilation basin (30) containing the ventilation area (25) and a filtration basin (31) containing the filtration area (26). Method according to Claim 13 or 14 , characterized in that the ventilation area (25) and the filtration area (26) are arranged in a common basin (33). Method according to the Claims 14 and 16 , characterized in that the sedimentation section (27) has an overflow weir (34) which is arranged in the common basin (33) between the ventilation area (25) and the filtration area (26). Method according to Claim 16 or 17 , characterized in that the common basin (33) is designed as a circular closed circulating circulation tank, in which the sedimentation section (27) from the ventilation area (25) leads to the filtration area (26). Method according to Claim 18 , characterized in that the circulating tank outside the sedimentation section (27) between the ventilation area (25) and the filtration area (26) includes a partition wall (38). Method according to Claim 18 or 19 , characterized in that in the circulation tank, a conveying device (39) for driving the water along the sedimentation path (27) is arranged. Water treatment plant for the treatment of contaminated waters and waters, in particular industrial wastewater, - with at least one basin (6), - With an inlet (7) for supplying contaminated water, with a drain (8) for discharging purified water, with an adding device (9) for adding the precipitant to the water, - with a ventilation device (11) for aerating the water, with the filter device (12), - With a control device (14) for controlling the feed device (9) and the ventilation device (11), - The controller (14) is configured and / or programmed to operate the water treatment plant (2) according to the method of any one of the preceding claims.

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