WO2024028751A1

WO2024028751A1 - Device and method for reconditioning fat-laden waste water

Info

Publication number: WO2024028751A1
Application number: PCT/IB2023/057761
Authority: WO
Inventors: Michael Kühlwein
Original assignee: TEC Austria GmbH
Priority date: 2022-08-01
Filing date: 2023-07-31
Publication date: 2024-02-08
Also published as: DE102022119269A1

Abstract

Disclosed is an apparatus (2) for treating water, comprising: - an inlet (4) for supplying the water to be treated, - a sedimentation device (200) downstream of the inlet (4) for sedimentation of suspended solids out of the water to be treated, wherein the sedimentation device (200) comprises at least - an enrichment path (8) for enriching the water to be treated with a coagulant (10) and - a regulation path (18), downstream of the enrichment path (8), for introducing a regulation agent (22) that adjusts the pH of the water to be treated, and - a filter device (28), downstream of the sedimentation device (200), having a filter medium (30) and - a reverse osmosis device (40), downstream of the filter device (28), for further cleaning of the water, characterized in that the apparatus (2), at the inlet side, has a ventilation device (108) for introducing oxygen-containing gas into the water to be treated, the ventilation device being arranged upstream of the sedimentation device (200).

Description

Device and method for processing fat-laden wastewater

Description

The present invention relates to a device for processing fat-laden wastewater and a method for carrying it out.

A multi-stage water treatment in the sedimentation device can enable both the reduction and/or removal of hardness formers, in particular calcium ions, and also lead to a reduction in TOC (total organic carbon) in drinking water. Although this two-stage procedure is known, it is not the standard procedure for water treatment and is usually contradictory, since the TOC reduction is achieved through a low pH value, typically between 4.0 and 7.3, and the reduction of hardness formers is typically achieved at higher pH values pH values between 9.5 and 11.5 can be achieved. The presence of TOCs also acts as an inhibitor in the precipitation of calcium.

When carrying out this special process, extensive subsequent steps are typically required, which makes the dimensioning of the system almost unsuitable for the use of 50 PE (population values) - 1000 PE. Such information becomes, among other things, specification used by small sewage treatment plants in accordance with DIN EN 12566 (Al version from 2003) and DWA-A 222.

The area of application of the system according to the invention for water treatment and in particular water processing should in particular be in the range of up to 1000 EWs, preferably up to 200 EWs, particularly preferably up to 50 EWs.

A decisive advantage of using such a system is its small installation space requirement and its low number of maintenance cycles.

Based on this preliminary consideration, the object of the present invention is to provide a system for water treatment for a comparatively small water volume of less than 1000 PE, which is characterized by a compact structure and almost maintenance-free operation with the highest possible cleaning efficiency. The aim is to prevent the water provided from tipping over into an anaerobic state, e.g. due to longer rest periods.

The present invention solves this problem by a device with the features of claim 1.

A device according to the invention for treating water comprises:

- an inlet for supplying the water to be treated,

- A sedimentation device connected to the inlet for sedimentation of suspended matter from the water to be treated.

The sedimentation device does not have to be directly connected to the inlet, but additional cleaning devices, in particular a grease separator and/or a skimming device, can be arranged between the inlet and the sedimentation device. The sedimentation device has at least one enrichment path for enriching the water to be treated with a coagulant and a regulating path following the enrichment path for introducing a regulating agent that adjusts the pH of the water.

In addition, the device according to the invention has a filter device with a filter medium connected to the sedimentation device.

Finally, the device according to the invention has a reverse osmosis device connected to the filter device for further purification of the water.

On the inlet side, the device has a ventilation device for introducing oxygen-containing gas into the water to be treated, which is arranged in front of the sedimentation device.

On the one hand, the aeration device serves to better mix the water and, on the other hand, it ensures that the water does not fall into an anaerobic state, so that the composition of the water changes due to decomposition processes and further contaminants are formed.

However, ventilation in a device with the aforementioned partial processing areas is not without problems, since the water tends to form foam when chemicals are added, which hinders the settling of solids. It has been found that it is therefore beneficial if aeration takes place before chemical supply.

The ventilation device can advantageously be part of a fat separation device with a receiving space for the water to be treated, the ventilation device having a compressed gas nozzle for introducing the oxygen-containing gas into the water to be treated in the receiving space Grease separator device. The fat separator device preferably works according to the principle of phase separation caused by gravity. This allows the ventilation device to be integrated into the device in a particularly space-saving manner.

Furthermore, the compressed gas nozzle of the ventilation device can have an inlet opening for releasing gas pressure into the liquid. In addition, the device, in particular the grease separator device, has a level measuring device and/or a limit switch. The level measuring device and/or the limit switch are designed in particular to monitor whether a maximum filling level has been reached. A maximum filling level is therefore specified for the receiving space of the fat separator device. The inlet opening of the aforementioned compressed gas nozzle is advantageously arranged below 70%, preferably below 50%, particularly preferably below 30% of the maximum filling level. This ensures that the gas has a sufficiently long path through the liquid and a correspondingly long time for contact and mixing.

In an advantageous, robust embodiment, the level measuring device has a mechanical level measurement, in particular a float.

The device can have one or more metering devices for supplying the coagulant and/or the regulating agent in the direction of flow. However, these one or more metering devices are arranged after the ventilation device. It has been shown that the supply of chemicals before or during ventilation promotes foam formation, which is advantageously avoided in this way.

The device can have a skimming device, in particular a belt skimmer, for skimming off a protruding fat phase, which is between the fat separator and the Sedimentation device, preferably in the direction of flow, is arranged immediately after the fat separator. While the fat separator removes large amounts of fat from the water, the skimming device removes any remaining fat and/or oil, such as grease eyes and the like. Upstream ventilation enables improved buoyancy and increased agglomeration of colloidal oil droplets, which can then be removed with the downstream skimming device. This results in optimal removal of fats and oils through the combination of ventilation and skimming device.

The ventilation device preferably has a system for generating compressed air. Although a gas bottle can also be provided, the generation of compressed air for this application is cost-effective and enables a compact design of the device according to the invention. The system for generating compressed air is designed to be advantageously controllable, particularly with regard to the pressure setting.

The system for generating compressed air can have one or more compressed air connections with other components of the device according to the invention. The device according to the invention advantageously has a cleaning device for introducing a cleaning medium for rinsing and/or CIP (clean in place) cleaning of the filter device and/or the reverse osmosis device, the aforementioned compressed air connections being part of this cleaning device, so that, for example, the cleaning medium is supplied with compressed air can be acted upon or residues of the cleaning medium can be blown out of the aforementioned devices.

The receiving space of the grease separator can advantageously have two chamber segments, which are spatially separated by a partition. The float can preferably be arranged in a first chamber segment. The compressed gas nozzle can advantageously be arranged in the second chamber segment. The chamber segments can have a connection area for level compensation, which is preferably arranged on the bottom side.

The receiving space of the fat separator can also have an overflow weir to separate a floating fat phase. This means that fat can be separated quantitatively through displacement. The oil and fat can then be collected in a collection tank together with the oil and/or fat phase separated by the skimming device.

The grease separator can advantageously be designed to collect water to be processed over a period of more than 5 days. Typically, anaerobic degradation already occurs during this period, which is advantageously prevented in particular by the ventilation device.

The ventilation device is preferably arranged immediately after a connection coupling of an inlet of the device for connection to a kitchen drain, in particular a siphon. This means that the amount of COD is reduced immediately after the inflow, which prevents the system from tipping over into the anaerobic state.

A method according to the invention for treating water with the above-described device according to the invention is carried out in such a way that the water is aerated, preferably before the introduction of further chemicals, the gas pressure of the gas introduced being at least 2 bar, preferably 3-5 bar. This prevents an anaerobic condition and ensures improved mixing and improved fat and oil separation in this and subsequent cleaning stages.

The water to be processed can be collected over a period of more than five days. For kitchen wastewater, this means that the collection can also take place over several days when the kitchen or restaurant is closed, during which no new water is supplied and without the system processing too small amounts of water under suboptimal conditions or without the water going into an anaerobic state and tipping over.

The characteristics, features and advantages of this invention described above and the manner in which these are achieved will become more understandable in connection with the following description of the exemplary embodiments, which will be explained in more detail in connection with the drawing. Show it:

Fig. 1 is a schematic diagram of a method according to the invention and a system.

The figure is a purely schematic representation. Actual geometric relationships may vary from the figure.

Reference is made to Figure 1, which shows an apparatus 2 for treating water. The water is particularly kitchen water with a high content of fat and other compounds produced in the kitchen.

The device 1 comprises an inlet 4 through which the water to be treated can be supplied in a flow direction 5, hereinafter also referred to as the flow direction. The inlet 4 can include a kitchen siphon.

The device then has a grease separator 100 after the inlet 4, which is arranged immediately downstream of the inlet in the direction of flow.

The maximum inflow quantity of water to be treated, in particular kitchen wastewater, to be processed by the system according to the invention can be at least 100 l/h, preferably between 150-500 l/h. The grease separator 100 has a container 101 which delimits a receiving space 113. The container 101 has at least one partition 102, which segments the container into at least two separation areas or chamber segments 104, 105. A line 103 between the inlet 4 and the grease separator 100 serves to feed the water to be treated into the first separation area 104. The second separation area 105 has an overflow 106. The partition 102 can in particular be designed as a baffle. The filling level of the first and/or second separation area 104, 105 is monitored via a filling level sensor 107, for example a float.

The grease separator further has a ventilation device 108 for introducing an oxygen-containing gas, in particular compressed air, into the water to be processed in the container 101.

This achieves thorough mixing and prevents the water from turning into an anaerobic state. The pressure should be at least 2 bar, preferably 3-5 bar. The ventilation device 108 can have a system for generating compressed air 109. A compressed gas nozzle 120, which, for example, is fixed to the wall of the container 101 in a medium-tight manner, has an inlet opening for gas into the water to be cleaned and is arranged in the lower region of the liquid level of the container 101, so that a sufficiently large distance is provided in which oxygen can be introduced into the liquid.

The water to be treated is then transferred, in particular pumped, into the pre-separator 110. The pre-separator 110 serves on the one hand as a sedimentation tank and on the other hand for further fat separation using a skimming device 111 in the form of a so-called belt skimmer 111.

Band skimmers or band skimming devices are larger

Facilities known per se. Floating fat is skimmed off using a conveyor belt. However, in the Practical application has shown that the fat content of the water to be treated is still surprisingly so high despite the previous fat separator that the use of the belt skimmer 111 significantly improves the water quality for the subsequent process steps.

The skimmed oils and fats are collected in a collecting container 112 and disposed of professionally together with other fats that occur in the kitchen, such as frying fat and drippings, by an appropriate disposal company.

After this pretreatment, the water to be treated is optimally prepared for subsequent sedimentation. The water to be treated from the pre-separator 110 is passed via a line 130 into a sedimentation device 200, which includes a lamella clarifier 230 in which the sedimentation of impurities takes place. In the transition between the pre-separator 110 and the lamellar clarifier, a coagulum 10, preferably an iron (III) solution, particularly preferably as an iron (III) chloride solution, is added. A corresponding dosing unit 140 for adjusting the flocculant content is arranged along line 130. Part of the line 130 and the dosing unit 140 are part of an enrichment path 8 of the sedimentation device 200.

In addition, the pH value is adjusted to a neutral or slightly basic value, preferably between 7.2-7.5. This can be done in particular by adding a regulating agent 22, preferably a basic agent, particularly preferably NaOH, in particular a NaOH solution , take place. A dosing unit 150 for adjusting the pH value is arranged along line 130. The dosing unit 150 and/or the line 130 and/or a means arranged along the line may have a pH sensor 151, which is connected to the dosing unit 150 by means of a signal connection, as a wireless connection or as a signal cable. In particular, the dosing unit 150 can have a control and evaluation unit for Processing the measurement signals from the pH sensor 151 and for setting the dosage amount of the alkaline agent for the water to be processed. Another part of the line 130 and the metering unit 150 are part of the regulation path 18 of the sedimentation device 200.

The flow path is designed in such a way that there is sufficient time for flocculation. A means 160 for reducing the flow velocity is arranged between the pre-separator 110 and the sedimentation device 200. The means can be arranged along the line 130 or in the line 130 or be part of the line 130. This facilitates sedimentation and reduces the tendency to turbulence. The means 160 for reducing the flow velocity is particularly preferably designed as a tubular reactor. The tubular reactor can have a temperature control device to provide constant binding conditions.

The sedimentation device 200 includes a lamella clarifier 230, and this has a conical sub-segment 201 on the bottom for settling the sediments, at the tapering end of which there is a sludge drain 202. At a neutral to basic pH value, hydroxide flakes form in the sedimentation device 200, in particular iron hydroxide flakes, which capture approximately 90% of the undissolved substances and 50% of the dissolved substances. The sedimented sludge is periodically discharged into a sludge collection tank 250 with a DM content of preferably 3-5%. The lamella clarifier preferably has a level measuring device 231 and/or a limit switch. Ideally, the level measuring device 231 and/or the limit switch or an arrangement of several limit switches detects both the total filling level and the filling level of the sludge or phase boundary, with emptying taking place not only based on the total filling level but based on one of the two values. A capacitive sensor can be used for this, which detects the phase boundary based on a change in capacitance. The sludge collection tank 250 has a sludge collection space 255 and a conical bottom 251 with a sludge drain 252 at the tapered end of the bottom 251. Furthermore, the sludge collection tank 250 has a fill level sensor and / or a fill level limit switch 253. When a predetermined fill level is reached, the sludge can be discharged from the sludge collection tank 250 are drained. By monitoring and/or determining the fill level, optimal post-sedimentation within the sludge collection tank 250 is achieved.

The sludge collection tank 250 has a permeable filter element 254, which preferably forms a wall region 256 of the sludge collection space 255, particularly preferably the conical bottom 251. Preferably, the permeable filter element 254 is a filter paper or filter cloth.

In the sludge collection tank 250, a liquid collection space 257 is arranged beyond the sludge collection space 255. In this liquid collection space 257, the retentate of the filter element 254 is collected while the permeate remains in the sludge collection space 250, thereby further concentrating the sludge phase. This preferably takes place over a period of 12-24 hours.

The retentate 258 is then returned from the liquid collection space 257 into the pre-separator 110, while the concentrated sludge 259, preferably after reaching the predetermined level, can be drained from the sludge collection space 255 and the sludge collection tank 250 and fed to a drying system 260, for example biological drying . A process for biological drying is basically known and a corresponding exemplary process for biological drying of sewage sludge is disclosed, among others, in DE 41 11 314 C2. The aforementioned document only describes a variant within the scope of the present invention and can also be done in another way. The dried mud can then be used, preferably together with collected food scraps from the collecting container 112 are processed into fertilizer.

The slat clarifier 230 has a large number of inclined slats 203, which are arranged obliquely at an angle of 2-45°, preferably 5-25°, compared to a vertical orientation of the slats. The sedimentation device designed as a lamella clarifier can also have a longitudinal axis 204, which is preferably arranged parallel to the vertical direction. The flow through the plate pack is from bottom to top. A gaseous medium, in particular air, can be blown in to support this and preferably. Accordingly, the sedimentation device 200 has a gas inlet, not shown, which is preferably arranged below individual lamellae or a lamella package.

The sedimentation device 200 also has an inlet opening 205 at which the line 130 opens into the sedimentation device 200. The inlet opening 205 is arranged above the sludge outlet 202. In addition, the sedimentation device 200 has an outlet opening 206 for a clarified liquid phase, which is arranged above the inlet opening 205. A transition 220 is attached to the drain opening 206. An overflow weir, not shown, is preferably present within the sedimentation device 200 and is positioned in the area of the drain opening 206.

The transfer 220 then opens into a storage container 310 of an ultrafiltration system 300. The ultrafiltration system 300 also includes a dynamic tangential flow filtration system (cross flow) 320 with one or more ceramic filtration disks 332, which are rotatably mounted in a housing 331. The average pore size of the ceramic discs can advantageously be between 10-50 nm. They define a so-called ceramic rotation membrane. The pre-cleaned wastewater is circulated between the dynamic tangential flow filtration system 320 and the storage container 310. A filtrate of 50-500 l/h, preferably between 150-400 l/h, is directed towards a receiver tank 410 of the reverse osmosis system 400. The ultrafiltration system has appropriate means, for example a pump, one or more lines, and a control unit that enables the rotation membrane to be flushed, preferably by generating backwash pulses. To control the periodicity of the generation of the backwash pulses, a sensor unit can be provided, in particular on a discharge line of the filtrate. A sensor unit can be, for example, a pressure sensor and/or an optical sensor for determining a turbidity content in the filtrate and/or a flow sensor.

Due to the return pulses, colloids and/or bacteria on the surface of the rotating membrane are removed and can be rinsed out as retentate or recirculated into the receiving container 310, thereby concentrating the supplied phase.

Short-chain fatty acids, which can cause a significant odor nuisance, such as butyric acid or similar, are not retained and are collected as part of the filtrate in the receiving tank 410 of the reverse osmosis system 400.

The reverse osmosis system 400 is equipped with a membrane 402 and is operated with a yield rate of preferably more than 60% by volume, preferably between 65-75% by volume. Reverse osmosis is known per se. The system is designed for a maximum provision of more than 100 l/h, preferably for a maximum provision of a quantity between 120-300 l/h. It has an osmosis container 410, for example with a wound membrane or another semi-permeable membrane 411, and an adjoining storage tank 420 for the permeate. The reverse osmosis system 400 has a drain line 430 for the permeate, which is arranged on a permeate drain 401 of the reverse osmosis system. The permeate provided meets all requirements for introduction into a conventional water network and can be used, for example, to flush toilets. Therefore, the drain line 430 can advantageously have a connection 431 to a sanitary system. The storage tank

420 is part of the drain line 430. The storage tank 420 also has a fill level and/or limit level monitoring device

421, which initiates emergency emptying when a certain limit level in the storage tank is reached.

A disinfection dosing unit 440 for feeding a disinfectant into the permeate is also arranged along the drain line 430. The disinfection dosing unit 440 has a storage tank with disinfectant for water disinfection of a predetermined concentration. Typically this can be chlorine or another disinfectant such as NaCIO, in particular between 0.1-1 ppm.

Furthermore, an activated carbon filter 450 is provided in or on the osmosis container 410 or along the drain line 430. This is preferably arranged in front of the disinfection dosing unit 440 in the direction of flow.

The osmosis container 410 has a concentrate drain 412, which serves to drain off a concentrate. The concentrate, which contains the impurities remaining after ultrafiltration, is returned to the grease separator 100 via the concentrate drain 412. An increased COD content of up to 3300 mg/l vs. 1000 mg/l can be detected in the concentrate. Due to the comparatively small amount of wastewater in the concentrate, the dirt load is not significant.

Detachable substances are completely removed by the above-described device 2 and semi-volatile lipophilic substances are largely removed. Over the course of a year, samples of kitchen wastewater were taken and various parameters were determined through full analyses:

1. Kitchen water before discharge

Amount of wastewater (m3/d) = 1.9

Semi-volatile lipophilic substances, known as TR. (mg/l) <150 COD, calculated as 02 (mg/l) < 1000

Detachable substances, calculated as ABS (ml/l) < 10

Temperature (°C) <35

2. Kitchen water at the ultrafiltration filtrate outlet

Amount of wastewater (m3/d) = 1.9 pH value 7.0 - 7.5

Semi-volatile lipophilic substances, calculated as TR (mg/l) <5 COD, calculated as O2 (mg/l) < 1000

Detachable substances, calculated as ABS (ml/l) < 1.0

Temperature (°C) <35

3. Kitchen water at the reverse osmosis concentrate drain

Amount of wastewater (m3/d) = 0.57 pH value 7.0 - 7.5

Semi-volatile lipophilic substances, calculated as TR (mg/l) <20 COD, calculated as O2 (mg/l) <3333

Detachable substances, calculated as ABS (ml/l) < 2.0

Temperature (°C) <35

4. Kitchen water at the reverse osmosis permeate drain

Amount of wastewater (m3/d) = 1.33 pH value 6.5 - 7.5

Semi-volatile lipophilic substances, calculated as TR (mg/l) <2.0

COD calculated as O2 (mg/l) <200

Detachable substances, calculated as ABS (ml/l) < 0.5

Temperature (°C) <35

Process the aforementioned method and the aforementioned device Kitchen water from system catering (QSR.) to service water that is suitable for flushing toilets or watering gardens.

All of the resulting kitchen water is almost completely purified of semi-volatile lipophilic substances (SLS) and settleable substances (ABS). The pH value of the wastewater is neutralized. The reverse osmosis concentrate, which reduces the wastewater flow by 70%, has an increased COD concentration while maintaining the same dirt load after ultrafiltration treatment when it returns to the grease separator. The dissolved and undissolved components of the wastewater are bound in the sludge, which can be processed in the dryer together with food waste into fertilizer, which can be used in organic farming.

Reference symbol list

2 device

4 inlet

5 flow direction

8 enrichment path

10 coagulant

18 Regulatory Path

22 regulatory means

100 grease separators

101 containers

102 partition

103 lines

104 separation area

105 separation area

106 overflow

107 level sensor

108 ventilation device

109 Device for generating compressed air

110 pre-separators

111 skimming device

112 collection containers

113 Receiving space of the grease separator container

120 compressed gas nozzle

130 line

140 dosing device

150 dosage unit

151 sensor

160 Means for reducing flow velocity

200 sedimentation facility

201 sub-segment

202 mud drain

203 slanted slats

204 longitudinal axis 205 inlet opening

206 drain opening

210 template containers

220 transition

230 lamella clarifiers

231 level gauge

250 sludge collection tank

251 floor

252 mud drains

253 Level sensor and/or level limit switch

254 filter element

255 mud collection room

256 wall area

257 liquid collection room

258 retentate

259 concentrated mud derived

260 drying system

300 ultrafiltration system

310 storage containers

331 housing

332 ceramic filtration discs

400 reverse osmosis system

401 Permeate drain

410 master tank / osmosis container

412 concentrate drain

420 storage tank

421 level and/or limit level monitoring device

430 drain line

431 connection (sanitary system)

440 disinfection dosing unit

450 activated carbon filters

Claims

Patent claims

1. Device (2) for treating water, comprising:

- an inlet (4) for supplying the water to be treated,

- A sedimentation device (200) adjoining the inlet (4) for sedimentation of suspended matter from the water to be treated, the sedimentation device (200) being at least

- an enrichment path (8) for enriching the water to be treated with a coagulant (10) and

- has a regulating path (18) adjoining the enrichment path for introducing a regulating agent (22) which adjusts the pH value of the water, and

- a filter device (28) adjoining the sedimentation device (200) with a filter medium (30) and

- a reverse osmosis device (40) adjoining the filter device (28) for further purification of the water, characterized in that the device (2) has a ventilation device (108) on the inlet side for introducing oxygen-containing gas into the water to be treated, which is arranged in front of the sedimentation device (200).

2. Device according to claim 1, characterized in that the ventilation device (108) is part of a grease separation device (100) with a receiving space (113) for the water to be treated, the ventilation device (108) having a compressed gas nozzle (120) for introduction of the oxygen-containing gas into the water to be treated into the receiving space (113) of the fat separation device (100).

3. Device according to claim 2, characterized in that the compressed gas nozzle (120) has an inlet opening, the grease separator device (100) having a level measuring device and/or a limit switch (107), the level measuring device and/or the limit switch (107 ) is designed to monitor whether a maximum filling level has been reached, and wherein the inlet opening of the compressed gas nozzle (120) is below 70% of the maximum filling level is arranged.

4. Device according to one of the preceding claims, characterized in that the level measuring device (107) has a mechanical level measurement, in particular a float.

5. Device according to one of the preceding claims, characterized in that the device (2) has one or more metering devices (140, 150) for supplying the coagulant (10) and / or the regulating agent (22) in the flow direction (5), whereby the one or more metering devices (140, 150) are arranged after the ventilation device (108).

6. Device according to one of the preceding claims, characterized in that the device (2) has a skimming device (111), in particular a belt skimmer, for skimming off a protruding fat phase, which is between the fat separator (100) and the sedimentation device (200), preferably in the flow direction (5) is arranged immediately after the grease separator (100).

7. Device according to one of the preceding claims, characterized in that the ventilation device (108) has a system for generating compressed air (109).

8. Device according to one of the preceding claims, characterized in that the receiving space (113) of the fat separator (100) has two chamber segments (104, 105), which are spatially separated by a partition (102).

9. Device according to one of the preceding claims, characterized in that the receiving space (113) of the fat separator (100) has an overflow weir for separating a floating fat phase.

10. Device according to one of the preceding claims, characterized in that the fat separator (100) is designed to collect water to be treated over a period of more than 5 days.

11. Device according to one of the preceding claims, characterized in that the ventilation device (108) is arranged immediately after a connecting coupling of an inlet (4) of the device (2) for connection to a kitchen drain, in particular a siphon.

12. A method for treating water with a device according to one of the preceding claims, characterized in that the gas pressure of the gas introduced is at least 2 bar, preferably 3-5 bar.

13. A method for treating water according to claim 12, characterized in that the water to be treated is collected over a period of more than five days.