DE102009017125A1 - Processing surface water, industrial water, brackish water and/or grey water to drinking water, comprises initially sucking the water by prefiltration, and subsequently subjecting the sucked water to microfiltration and/or ultrafiltration - Google Patents

Abstract

The method comprises initially sucking the water by prefiltration, and subsequently subjecting the sucked water to microfiltration and/or ultrafiltration under pressure and then to nanofiltration, where an antiscalant is dosed to the water in a flow direction before the nanofiltration and a substance providing chlorine is dosed to the water after the nanofiltration. A free chlorine-eliminating chemical is provided for the purpose of dosage in the flow direction before the nanofiltration, so that the water to be prepared contains chlorine. The water is subjected to an UV-sterilization. The method comprises initially sucking the water by prefiltration, and subsequently subjecting the sucked water to microfiltration and/or ultrafiltration under pressure and then to nanofiltration, where an antiscalant is dosed to the water in a flow direction before the nanofiltration and a substance providing chlorine is dosed to the water after the nanofiltration. A free chlorine-eliminating chemical is provided for the purpose of dosage in the flow direction before the nanofiltration, so that the water to be prepared contains chlorine. The water is subjected to an UV-sterilization after the nanofiltration. The retentate occurring during the nanofiltration is partially recirculated to the water before the microfiltration and/or ultrafiltration or between the microfiltration and/or ultrafiltration and the nanofiltration, where the antiscalant and optionally the free chlorine-eliminating chemical are dosed to the retentate before recirculation. The part of the retentate is transferred to receiving water. The retentate is partially supplied to a liquid container, in which the antiscalant and optionally the free chlorine-eliminating chemical are dosed to the retentate, where the retentate is pumped from the liquid container and then is recirculated. The retentate is sub-divided into a first- and a second retentate partial flow above the liquid container. The first retentate partial flow is supplied to the liquid container and the second retentate partial flow is supplied to a jet pump for pumping the retentate from the liquid container. The dosage step is carried out using a tube pump and/or a piezo-membrane pump. During the prefiltration, 80-90% of the microbiological germs contained in the water are held back. During microfiltration and/or ultrafiltration and nanofiltration, the microbiological germs are held back in a circumference, so that the water is delivered up to 95-99% from the germs after the microfiltration and/or ultrafiltration and up to 99.9% from the germs after the nanofiltration. The prefiltration and microfiltration and/or ultrafiltration are optionally intermittently flushed back using filtered backwashing air that is filtered using microfiltration and is stored in a pressurized container under overpressure. The water is supplied to a storage container (5) after sucking by prefiltration and then initially transferred to the microfiltration and/or ultrafiltration. An independent claim is included for a device for processing surface water, industrial water, brackish water and/or grey water to drinking water.

Description

The The invention relates to a method and a device for processing of water, in particular of surfaces, service, brackish and / or gray water, to drinking water.

In the prior art, it is well known to produce from slightly polluted water such as gray and brackish water, but also from rainwater clear water that is hygienically clean and for example, garden irrigation, cleaning fluids, toilet flushing or the like can be used. For this purpose, mechanical treatment facilities such as rakes, screens, filters, but also chemical methods are proposed. Examples of the treatment of rainwater with the help of filters are the DE 296 00 039 U1 and DE 197 31 887 A1 refer to. However, the water treatment plants described therein are neither intended nor suitable to provide drinking water quality water.

at Environmental disasters are often the problem of that affected population, but also the most in large Number of invigorated drinkers quickly drinkable water to provide. An appropriate water treatment plant should therefore have a compact design to make it easy and can be quickly transported to a desired location. The same applies to military deployment in Crisis areas, but also for the drinking water supply not connected to the public water supply Houses like mountain huts, hotels or remote farms. Where such connections exist, one could Water treatment plant that can provide drinking water, to serve to conserve drinking water resources by accumulating rain or Gray water is collected and processed into drinking water.

To supply the population with emergency drinking water in the prior art, a portable Gruppenfiltriergerät known (see. DE 35 14 189 C2 ). This is a hand-operated device that is only suitable for supplying smaller groups of people with drinking water. As far as there is a chemical treatment, it serves the treatment of contaminated with A, B and C-agents surface water.

Of the Invention is based on the object, a method and an apparatus for the treatment of slightly polluted water such as surface, custom, Brackish and / or gray water provide, with the or the water in drinking water quality in significant quantities and over can be made longer time, with the device characterized in that their individual parts to a compact Put together a device that is easy to transport.

These The task is - as far as the process is concerned - by solved that water over first aspirated a prefiltration and then under pressure a micro and / or ultrafiltration and then a nanofiltration is subjected, with the water in the flow direction at least one antiscalant before nanofiltration and after nanofiltration a chlorine-providing substance is added and wherein in order Metering in the flow direction before nanofiltration a free chlorine eliminating chemical in case is provided that the water to be treated contains chlorine. basic idea The invention is the water to be treated at least one Three-stage filtration with increasingly higher filtration fineness (decreasing pore size) subject and to condition the water by adding certain chemicals, that the formation of the filtration effect impairing Coverings at least on the retentate side of the nanofiltration is avoided and you get a water in which the multiplication prevented microbiological germs for a long time is.

What the filter finenesses or pore sizes at Filtrations used in the process according to the invention there is general agreement that one of Microfiltration speaks when particles get bigger retained as 0.1 μm, by ultrafiltration, if particles larger than 0.01 μm are retained and nanofiltration when particles are larger 0.001 μm are retained. The respectively required Pressure difference is generally associated with microfiltration 0.1 to 2 bar, in ultrafiltration at 0.1 to 5 bar and at Nanofiltration at 3 to 20 bar.

In order to it does not lead to deposits on the filter surface At least the nanofiltration comes, the water becomes an antiscalant dosed, with the hardness and silicates as the main cause of Fouling stabilized or eliminated. Such antiscalants are based, for example, on phosphonic acid or polyacrylates. The additional provision of free chlorine eliminating Chemicals happens in case the reprocessed Water has already been pretreated with chlorine to increase the content of to reduce microbiological germs. Will such water with prepared according to the method of the invention should an antichlorine substance is added to the water, because it is also free Chlorine is harmful in the filtration of the water to be treated.

With the method according to the invention, the production of drinking water from water, which is not so heavily polluted as black water, with relatively simple process steps possible, wherein the method is characterized by the fact that it does not require plant technology with otherwise proven elements that allows the treatment of larger amounts of water to drinking water.

In Training of the invention is provided that the water after the Nanofiltration additionally subjected to UV sterilization becomes. This can be useful if you have a large number of germs be.

When Chlorine-providing substance is especially suitable for chlorine dioxide. The addition of chlorine dioxide should be done in a way that the chlorine dioxide concentration in the water is between 0.05 mg / l and 0.2 mg / l. As a free chlorine eliminating substance is suitable especially sodium hydrogen sulfite.

In Particularly advantageous embodiment should in the nanofiltration accumulating retentate at least partially to the water in front of the micro- or ultrafiltration or between this and the nanofiltration be recycled and the retentate before recycling at least the antiscalant and optionally the free chlorine eliminating Substance are added. Through the return can be a high flow over the Membrane surfaces for the purpose of preventing deposits and to control the ionic boundary layers. This is especially true in filtrations with low throughput. The return also offers the possibility of a part of the retentate to discard for the purpose of desalination, in particular to deliver to a receiving water.

For the addition of the antiscalant and optionally the chlorine eliminating Substance suggests the invention that the retentate at least partially supplied to a liquid container, where the antiscalant and possibly the free chlorine eliminating Substance is added to the retentate or be, and that the retentate is pumped out of the liquid container and led away. This has the advantage that the dosing does not violate the fluid pressure must work in a fluid line, but the in the liquid container collected retentate can be added practically without pressure. Therefore, the metered addition For example, by means of a peristaltic pump and / or one Piezomembranpumpe be performed. The subsequent Pumping out of the conditioned retentate ensures a intense turbulence and thus uniform Distribution of chemicals across the cross section of the retentate stream. The chemical additive can be added in highly concentrated form which saves transport costs. Furthermore it is not necessary to dilute the chemical additive.

In a particularly advantageous embodiment, the Retentate in front of the container in a first and a second Retentatteilstrom divided and the first retentate partial stream the Liquid container and the second retentate partial stream a pump for pumping the retentate from the liquid container fed. Such a division of the retentate is in particular then advantageous if a jet pump is used as the pump and if the second retentate partial stream in the jet pump is a propulsion jet forms, with the first retentate partial stream from the liquid container is sucked off. The jet pump does not need an external one Drive, but uses the existing in the second retentate partial flow Pressure energy for the formation of the propulsion jet, so over the suction side of the jet pump in the liquid container Conditioned retentate can be aspirated. The jet pump can be easily formed, for example, reduced to an acceleration section for the second retentate substream, so that negative pressure areas arise, in the retentate from the liquid container can flow into it. This is an intensive mixing and thus a uniform distribution of the chemical additive achieved in the combined retentate stream.

For the grading of the filtration stages, it is advantageous if in the Pre-filtration 80 to 90% of the microbiological contained in the water Germs are withheld. For macro- or ultrafiltration and in nanofiltration to a microbiological extent Germs are retained, that the water after the micro- or ultrafiltration to 95 to 99% and after the nanofiltration too 99.9% is exempt from such germs. In this way receives you get water in drinking water quality, due to the subsequent Addition of the chlorine-providing substance in terms of the Germ plant is stabilized and therefore also storable.

Around a clogging of prefiltration and micro- or ultrafiltration to avoid is provided according to the invention that at least a filtration step, preferably both filtration steps intermittently be backwashed. The backwashing can at the filtration stages different needs occur as needed. In practice, you will backwash more frequently during prefiltration as in micro- or ultrafiltration. Is particularly advantageous it if the backwash by means of filtered, preferably micro-filtered backwash air takes place. The backwash air should be in a pressure vessel be stored under overpressure to open after opening a valve abruptly fed to the aforementioned filtration stages can be.

According to the invention it is further provided that the water is first fed to a storage container after the suction via the prefiltration and then passed on to micro- or ultrafiltration. In this way, the water sucked in via the prefiltration can be temporarily stored before it is then passed on from the storage tank to the microfiltration or ultrafiltration. Due to the intermediate storage, the prefiltration can be shut down and cleaned, in particular backwashed, while the water treatment can continue under recourse to the water collected in the storage tank. In this way it is possible durchzu lead the cleaning of the prefiltration at short intervals, especially if the water to be purified is heavily contaminated with solids.

Of the Part of the object relating to the device according to the invention solved a device that has a waterway, in one after the other in the flow direction, a prefiltration device, a micro and / or ultrafiltration device and then a nanofiltration device are arranged, wherein in the water line between prefiltration and micro- or ultrafiltration means a self-priming pump for sucking the water through the prefiltration device is provided and wherein at least two metering devices present which are the first connection to the water route after the nanofiltration device and the second connection to the Water line in front of the nanofiltration device has. With help This device can the method of the invention be realized, so that those mentioned in this context Benefits are achieved.

The Device is characterized by the fact that their items too a compact and therefore easy to transport and little Stand occupying water treatment plant put together can be and that this treatment plant anyway Water in drinking water quality in significant quantities Can provide. Suitable for processing in particular surface, service, brackish and / or Gray water, including rainwater, d. H. Water quality, which are also regularly available in case of catastrophes stand. The device according to the invention is suitable But also to conserve resources in areas where larger Amounts of the aforementioned water qualities incurred, for example in hotels, on ships etc. In addition, the retentate energetically usable.

As already mentioned, the nanofiltration can a UV sterilization device can be subordinated, if necessary is.

The second metering device should have at least two metering devices for the addition of different chemicals, in the present Case of an antiscalant and a free chlorine-eliminating substance, exhibit. The second metering device preferably has connection to a return line coming from the nanofiltration device back to the water line in front of the micro- or ultrafiltration device or between this and the nanofiltration device goes. there should the nanofiltration device in the water line a Pressure pump upstream and the return line On the suction side of the pressure pump, open into the water section.

Especially It is advantageous if the second metering device depressurizes can meter in the return line. this has the advantage of a simple construction of the metering device. For the metered addition can then hose and / or piezomembrane pumps be used. A pressureless dosing is possible if part of the return line is a liquid container is, in which the second metering device opens, and when in the return line to the liquid container a pump for pumping the liquid container supplied retentate is provided. It is from particular advantage, if from the return line in front of the liquid container a bypass line branches off to the pump. The pump can then be designed as a jet pump be, wherein the bypass line connected to the jet pump in such a way is that the guided over the bypass line Retentatteilstrom forms a propulsion jet, with which the retentate is sucked out of the liquid container. there is the jet pump expediently outside arranged the liquid container. But also an arrangement within the liquid container is conceivable. As already mentioned, the jet pump ensures a particularly intensive mixing of the two retentate substreams and thus even distribution of the or the Chemical (s).

The The invention further provides that the liquid container is divided into an antechamber and into a mixing chamber, which together communicate with the return line inlet side into the antechamber and the second metering device in open the mixing chamber. The division has the advantage that creates a turbulent flow in the mixing chamber can be. This is preferably done by having antechamber and mixing chamber are divided by a baffle, the distance to the bottom of the liquid container, so that the transfer of the retentate from the antechamber into the mixing chamber at the bottom of the liquid container he follows. It should be the drain for the liquid start in this area, allowing a drain of the liquid done in well mixed form.

According to a further feature of the invention, it is proposed that the liquid container ei NEN further sequence, in particular designed as an overflow, via which a drain stream is discharged. This process is expediently carried out from the antechamber so that no losses of mixed chemicals arise. With the help of this process, retentate can be diverted for the purpose of desalination and fed to a receiving water. Downstream of the sequence may be a valve and then a volume measuring device to monitor the proportion of the process can.

The Pre-filtration device is designed such that already there 80 to 90%, the retained microbiological germs contained in the water become. It should have a filter fineness of 1 μm or below, preferably less than 0.5 μm. The Prefiltration device can, for example, at least one filter cartridge, preferably made of polyethylene. It is understood that the Pre-filtration device also several filter elements, for example in the form of filter cartridges.

The Micro- or ultrafiltration device and the nanofiltration device are designed to be in a range of microbiological germs withhold the water after the microfiltration or ultrafiltration device to 95 to 99% and after the nanofiltration 99.9% of such Germinating is free. Again, it is understood that the respective Filtration facilities multiple filter elements in parallel and / or may be arranged serially, in particular if larger volumes are to be processed.

In Another embodiment of the invention provides that the prefiltration device and the micro- or ultrafiltration device a backwashing is assigned, which expediently for the supply of backwashing air is formed. It is particularly advantageous if the backwashing device with a microfiltration device for filtering the backwash air is provided. To a larger amount Provide backwash air can, should the backwash air in one Pressure vessels are stored.

To The invention also proposes that the water path downstream the prefiltration device and the self-priming pump in a storage container opens out of the out Water route to the micro or

Ultrafiltration device goes. In the storage container is a certain amount prefiltered water, which is available to the water treatment in the following components upright when the water absorption via the prefiltration device for the purpose of their cleaning in particular by means of backwashing is interrupted.

The Micro- or ultrafiltration can ceramic and / or have sintered filter media while for the nanofiltration a desalting filter membrane as a filter medium it is a possibility.

In the drawing, the invention with reference to an embodiment is illustrated in more detail. She shows a total of 1 designated water treatment plant for the treatment of non-potable water to drinking water in a schematic representation of their individual parts.

The water treatment plant 1 has a waterway 2 in the form of a water pipe with facilities or components contained therein. The water route 2 starts with a pre-filter 3 , which is designed as a sintered plastic filter candle with a filter fineness in the single-digit micron range. The pre-filter 3 is in the water to be treated, for example, a polluted natural waters, submersible. It forms with a downstream, self-priming suction pump 4 a functional unit, the waterway 2 is formed in between as a flexible hose. The suction pump 4 ensures the suction of the water to be cleaned, ie the pre-filter 3 works in a light vacuum range. This results in a very uniform coverage of the surface of the pre-filter 3 , wherein the increasing cover layer formation on the surface of the prefilter 3 supports the filtration effect. The cover layer remains relatively loose and permeable. The pre-filter 3 ensures that about 80 to 90% of the microbiological germs contained in the water, especially bacteria, are retained.

That with the help of the suction pump 4 pumped water enters a storage tank 5 in which the water is collected. In the lower area has the storage tank 5 an exit 6 for the further course of the water route 2 , By means of a pressure pump 7 the water gets out of the storage tank 5 sucked off and passes over the waterway 2 in a microfilter 8th - This may also be an ultrafilter - from a ceramic or sintered material with a filter fineness below 1 .mu.m, preferably below 0.5 microns. Because of this filter fineness, the water is after the microfilter 8th at least 95% free of microbiological germs.

The microfilter 8th follows a nanofilter 9 one in the waterway 2 built-in pressure pump 10 upstream. The nanofilter 9 has a filtration fineness of less than 0.01 μm, so that the permeate is at least 99.9% freed from microbial germs. The permeate then passes through a UV sterilizer 11 in which remain in the water ne germs are killed with UV rays. Thereafter, the water is stored in a storage tank 12 collected. From the storage tank 12 can the retained water by means of a product pump 13 to a personal needs station 14 or to third-party consumers 15 be encouraged.

To nucleate, especially in the storage tank 13 and in the storage tank 5 to prevent is a (first) metering device 16 provided that a dosing device 17 having. The dosing device 17 has a chemical reservoir in which chlorine dioxide is kept, and a metering pump by means of which the chlorine dioxide can be withdrawn from the chemical reservoir in the required amount. To the dosing device 17 closes a central Dosierzuleitung 18 from which a first branch 19 downstream of the UV sterilizer 11 in the waterway 2 empties. A second branch 20 leads to the storage container 5 , Valves can be used to control the amount of chlorine dioxide over the first and second branches 19 . 20 to be led.

The nanofilter 9 associated with a retentate return, here with a (second) metering device 21 combined. For the retentate recycling, the nanofilter 9 a retentate drain 22 on, which is in a first Retentatleitung 23 and a second retentate line 24 divides. The first retentate line 23 flows through a valve 25 from above into a liquid container 26 , The second retentate line 24 bypasses the liquid container as a bypass 26 and flows into a jet pump 27 , whose suction side with a suction pipe 28 connected to the liquid container 26 protrudes.

The liquid container 26 is over a diving wall 29 in an antechamber 30 and a mixing chamber 31 divided up. The first retentate line 23 flows into the antechamber 30 , The diving wall 29 is to the ground 32 of the liquid container 26 spaced so that in the antechamber 30 incoming retentate at the bottom of the baffle 29 into the mixing chamber 31 can flow into it.

From the antechamber 30 of the liquid container 26 branches a drain line 33 from that to a receiving water 34 goes. About the drain line 33 A certain volume flow of the retentate can be removed from the retentate recycling for the purpose of desalination. By a valve not shown here, the flow rate can be adjusted. The drain line 33 At the same time, it can also constitute an overflow, which is the level of liquid in the liquid container 26 constant at the level of the drain line 33 going overflow.

To the metering device 21 include two dosing devices 35 . 36 with each from above into the liquid container 26 opening metering lines 37 . 38 , The dispensers 35 . 36 each contain a chemical reservoir with subsequent metering pump, which may be formed, for example, as a peristaltic pump or piezo-membrane pump. The metering pumps remove a chemical from the respectively assigned chemical reservoir and convey it via the associated metering supply line 37 . 38 virtually depressurized in the mixing chamber 31 of the liquid container 26 ,

In the first dosing device 35 An antiscalant can be held up. Such agents serve to prevent deposits on the membrane surface of the nanofilter 9 due to the exceeding of solubility limits. The addition of antiscalant on the basis of phosphonic acid or polyacrylates, the formation of such mostly consisting of hardness and silicates deposits can be avoided. In the second dosing device 36 For example, a reducing agent may be provided for dechlorination, for example, sodium hydrogen sulfite. It is added when the water to be treated has been strongly chlorinated before. In addition, the addition of any free chlorine from the supply of chlorine dioxide in the storage container 5 away.

In operation, this partitions out of the nanofilter 9 about the retentate process 22 led out retentate in the first and in the second Retentatleitung 23 . 24 , wherein the respective position of the valve 25 determines the ratio of the two retentate streams. The over the first retentate line 23 in the antechamber 30 incoming retentate partial flow must pass through the narrow opening below the baffle 29 into the mixing chamber 31 flow. This results in an underflow with high turbulence. This in turn ensures that the of the dispensers 35 . 36 chemicals introduced intensively with the in the mixing chamber 31 mix retentate.

The suction tube 28 protrudes so deep into the mixing chamber 31 into it, that sucked the retentate in the particularly turbulent area and the jet pump 27 is supplied. In the jet pump 27 is due to the retentate substream passing through the second retentate line 24 flows, a propulsion jet using the pressure energy generated in the retentate, which not only the suction of the liquid in the container 26 Retentats effected, but also an intensive mixing of this part of the retentate with that on the second Retentatleitung 24 the jet pump 27 supplied retentate partial flow causes. The retentate leaves the jet pump 27 via a return line 39 , which on the suction side of the pressure pump 10 in the water route 2 empties. In this way, the nanofilter receives 9 With the above-mentioned chemicals conditioned water, wherein in the pressure pump 10 intensive mixing of conditioned retentate and microfilter 8th coming water.

The pre-filter 3 and the microfilter 8th associated with a backwashing 40 , by means of the pre-filter 3 and the microfilter 8th Compressed air can be supplied. The backwashing device 40 points inside a housing 41 a microfilter and a supplied via an air pump and the microfilter compressed air storage with, for example, 30 liters in volume. The compressed air contained in it is due to the filtering in the microfilter free of germs and other impurities. From the compressed air storage go air supply lines 42 . 43 to the permeate pages of prefilter 3 and microfilters 8th , Associated with the compressed air reservoir is a valve, which is normally closed, but is opened for a backwashing process.

The cleaning of the pre-filter 3 and the microfilter 8th usually occurs with different frequencies. Especially when heavily polluted water has to be treated with solids, it is necessary to use the pre-filter 3 to be freed at short intervals from the covering forming on its retentate side. In this case, the suction pump 4 shut off, leaving the water supply to the storage tank 5 is interrupted. Then the valve is opened at the compressed air reservoir. At the same time provide valves in the air supply lines 42 . 43 for that only the air supply 42 Compressed air is applied. It flows then the full contents of the compressed air reservoir abruptly over the air supply 42 into the permeate chamber of the prefilter 3 , The compressed air uses this in the pre-filter 3 stored water for transport within the pore structures of the prefilter 3 trapped contaminants and to detonate the contaminant layers formed on the retentate side.

Subsequent to the backwashing process, the contaminants present on the retentate sides are removed from the housing of the prefilter by means of air and the water present there 3 pushed out. This process is completed within a few minutes. Meanwhile, the water treatment in the subsequent components of the water route 2 continue running, in which case on the in the storage container 5 retained water is used. The volume of the storage tank 5 is sized so that it is sufficient to allow the water treatment during the cleaning of the pre-filter 3 does not have to be interrupted. After completion of the cleaning, the suction pump 4 switched back on. The promotion is such that the storage tank 5 then replenished to the intended level.

The cleaning of the microfilter 8th is only necessary in much larger time intervals. In this case, however, the entire water treatment is stopped, and it is then compressed air from the compressed air reservoir via the air supply line 43 on the permeate side of the microfilter 8th given. Preferably, the cleaning of the prefilter is also carried out simultaneously 3 in the sense described above.

The water treatment plant 1 also has a control air device 44 on. In her case 45 there is also a compressed air storage. He puts over outlet pipes 46 Control air for actuating valves of the water treatment plant 1 to disposal.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 29600039 U1 [0002]
• DE 19731887 A1 [0002]
• - DE 3514189 C2 [0004]

Claims (41)

Process for the treatment of water, in particular of surface, service, brackish and / or greywater to drinking water, in which the water is first filtered via a prefiltration ( 3 ) and then under pressure of a micro- and / or ultrafiltration ( 8th ) and then a nanofiltration ( 9 ), wherein the water in the flow direction before the nanofiltration ( 9 ) at least one antiscalant and after nanofiltration ( 9 ) a chlorine-providing substance are metered in and wherein for the purpose of metering in the flow direction before the nanofiltration ( 9 ) a free chlorine-eliminating chemical is provided in case the water to be treated contains chlorine. A method according to claim 1, characterized in that the water after the nanofiltration ( 9 ) of a UV sterilization ( 11 ) is subjected. Method according to claim 1 or 2, characterized Chlorine dioxide is metered in as chlorine-providing substance. Method according to claim 3, characterized that the addition of the chlorine dioxide takes place in such a way that the chlorine dioxide concentration in the water between 0.05 mg / l and 0.2 mg / l lies. Method according to one of claims 1 to 4, characterized in that as the free chlorine eliminating substance Sodium hydrogen sulfite is added. Method according to one of claims 1 to 5, characterized in that in the nanofiltration ( 9 ) at least partially the water before micro- or ultrafiltration ( 8th ) or between this and the nanofiltration ( 9 ) and at least the antiscalant and, if appropriate, the free chlorine-eliminating substance are added to the retentate prior to recycling. A method according to claim 6, characterized in that a part of the retentate discarded, in particular to a receiving water ( 34 ) is delivered. A method according to claim 6 or 7, characterized in that the retentate at least partially a liquid container ( 26 ) is supplied, in which the antiscalant and optionally the free chlorine-eliminating substance is added to the retentate or be, and that the retentate from the liquid container ( 26 ) is pumped off and recycled. A method according to claim 7 or 8, characterized in that the retentate in front of the liquid container ( 26 ) into a first and a second retentate substream ( 23 . 24 ) and the first retentate substream ( 23 ) the liquid container ( 26 ) and the second retentate substream ( 24 ) a pump, in particular a jet pump ( 27 ), for pumping the retentate from the liquid container ( 26 ) is supplied. Method according to one of claims 1 to 9, characterized in that the metered addition by means of each a peristaltic pump and / or a piezo-membrane pump performed becomes. Method according to one of the preceding claims, characterized in that in the prefiltration ( 3 ) 80 to 90% of the microbiological germs contained in the water are retained. Method according to one of claims 1 to 11, characterized in that in micro- or ultrafiltration ( 8th ) and nanofiltration ( 9 ) are retained to an extent microbiological germs that the water after micro- or ultrafiltration ( 8th ) to 95 to 99% and after nanofiltration ( 9 ) is 99.9% exempt from such germs. Method according to one of claims 1 to 12, characterized in that the prefiltration ( 3 ) and micro- or ultrafiltration ( 8th ) are optionally backwashed intermittently, in particular by means of filtered Rückspülluft. Method according to claim 13, characterized in that that the backwash air by microfiltration is filtered. Method according to claim 14, characterized in that that the backwash air in a pressure vessel is stored under overpressure. Method according to one of claims 1 to 15, characterized in that the water after the suction via the prefiltration ( 3 ) a storage container ( 5 ) and then only the micro- or ultrafiltration ( 9 ). Contraption ( 1 ) for the treatment of water, in particular surface, service, brackish and / or gray water to drinking water, wherein the device ( 1 ) a waterway ( 2 ) has, as seen in the flow direction one after the other a prefiltration device ( 3 ), a micro- and / or ultrafiltration device ( 8th ) and then a nanofiltration device ( 9 ) are arranged, wherein in the waterway ( 2 ) between prefiltration device ( 3 ) and micro- or ultrafiltration device ( 8th ) a self-priming pump ( 4 ) for the suction of the water through the prefiltration device ( 3 ), and that at least two metering devices ( 16 . 21 ), of which the first connection to the waterway ( 2 ) after the nano filtration device ( 9 ) and the second connection to the waterway ( 2 ) in front of the nanofiltration device ( 9 ) Has. Apparatus according to claim 17, characterized in that after the nanofiltration device ( 9 ) a UV sterilization device ( 11 ) is arranged. Apparatus according to claim 17 or 18, characterized in that the second metering device ( 21 ) at least two dosing devices ( 35 . 36 ) for the metered addition of different chemicals. Device according to one of claims 17 to 19, characterized in that the nanofiltration device ( 9 ) a retentate branch ( 22 ), which via a return line ( 23 . 28 . 39 ) back to the waterway ( 2 ) in front of the micro- or ultrafiltration device ( 8th ) or between this and the nanofiltration device ( 9 ), the second metering device ( 21 ) Connection to the return line ( 23 . 28 . 39 ) Has. Apparatus according to claim 20, characterized in that the nanofiltration device ( 9 ) in the waterway ( 2 ) a pressure pump ( 10 ) and that the return line ( 23 . 28 . 39 ) on the suction side of the pressure pump ( 10 ) into the waterway ( 2 ) opens. Apparatus according to claim 20 or 21, characterized in that part of the return line ( 23 . 28 . 39 ) a liquid container ( 26 ) into which the second metering device ( 21 ) and that in the return line ( 28 ) after the liquid container ( 26 ) a pump ( 27 ) for pumping the liquid container ( 26 ) supplied retentate is provided. Apparatus according to claim 22, characterized in that of the return line ( 22 ) in front of the liquid container ( 26 ) a bypass line ( 24 ) to the pump ( 27 ) branches off. Apparatus according to claim 23, characterized in that the pump as a jet pump ( 27 ) is formed and the bypass line ( 24 ) with the jet pump ( 27 ) is connected in such a way that via the bypass line ( 24 ) Retentatteilstrom formed a driving jet with which the retentate from the liquid container ( 26 ) is sucked. Device according to one of claims 22 to 24, characterized in that the liquid container ( 26 ) in an antechamber ( 30 ) and a mixing chamber ( 31 ), which communicate with each other, the return line ( 23 ) on the inlet side into the antechamber ( 30 ) and the second metering device ( 21 ) into the mixing chamber ( 31 ). Device according to claim 25, characterized in that antechamber ( 30 ) and mixing chamber ( 31 ) through a baffle ( 29 ), the distance to the ground ( 32 ) of the liquid container ( 26 ) Has. Device according to one of claims 22 to 26, characterized in that the return line ( 28 ) downstream in the lower half of the liquid container ( 26 ) begins. Device according to one of claims 22 to 27, characterized in that the liquid container ( 26 ) a further process ( 33 ), via which a drain stream is discharged. Device according to claim 28, characterized in that the process ( 33 ) is followed by a valve and then a volume measuring device. Device according to one of claims 17 to 29, characterized in that the prefiltration device ( 3 ) is designed such that 80 to 90% of the microbiological germs contained in the water are retained. Device according to one of claims 17 to 30, characterized in that the prefiltration device ( 3 ) has a filtration fineness of 1 μm or less. Device according to one of claims 17 to 31, characterized in that the prefiltration device ( 3 ) at least one filter candle, preferably made of polyethylene. Device according to one of claims 17 to 32, characterized in that the micro- or ultrafiltration device ( 8th ) and the nanofiltration device ( 9 ) are formed in such a way that to a certain extent microbiological germs are retained, that the water after the micro- or ultrafiltration device ( 8th ) to 95 to 99% and after the nanofiltration device ( 9 ) is 99.9% exempt from such germs. Device according to one of claims 17 to 33, characterized in that the prefiltration device ( 3 ) and the micro- or ultrafiltration device ( 5 ) a backwashing device ( 40 ) assigned. Apparatus according to claim 34, characterized in that the backwashing device ( 40 ) is designed for the supply of backwashing air. Apparatus according to claim 35, characterized ge indicates that the backwashing device ( 40 ) is provided with a microfiltration device for filtering the backwash air. Apparatus according to claim 35 or 36, characterized in that the backwashing device ( 40 ) has a pressure vessel for storing the backwash air under pressure. Device according to one of claims 17 to 37, characterized in that the waterway ( 2 ) downstream of the self-priming pump ( 4 ) into a storage container ( 5 ), out of which the water route ( 2 ) to the micro- or ultrafiltration device ( 9 ) goes. Device according to one of claims 17 to 38, characterized in that in the waterway ( 2 ) between the micro- or ultrafiltration device ( 8th ) and before the nanofiltration device ( 9 ) a pump ( 10 ) is arranged. Device according to one of claims 17 to 39, characterized in that the micro- or ultrafiltration device ( 8th ) has ceramic and / or sintered filter media. Device according to one of claims 17 to 40, characterized in that the nanofiltration ( 9 ) has a desalting filter membrane as a filter medium.