SE538014C2

SE538014C2 - Device for membrane filtration of water with free radicals and backwash with air and ultrasound

Info

Publication number: SE538014C2
Application number: SE1200628A
Authority: SE
Inventors: Bo Pahlen
Original assignee: Tendac Ab
Priority date: 2012-11-30
Filing date: 2012-11-30
Publication date: 2016-02-09
Also published as: WO2014084782A1; SE1200628A1

Abstract

SAMMAN DRAG Metod for avlagsnande av vattenfororeningar med membranfiltrering och framstall- fling av fria radikaler, som reducerar fri och kemisk lOst organisk substans mm. Metoden innefattar aven ett fOrfarande fOr kontinuerlig rensning av membranytan och ett slutligt omintetgorande av de fria radikalerna med antioxidanter samt ett backspolsfOrfarande med luft. SUMMARY Method for removal of water pollutants with membrane filtration and production of free radicals, which reduce free and chemically dissolved organic matter etc. The method also comprises a process for continuous cleaning of the membrane surface and a final destruction of the free radicals with antioxidants and a backwash process with air.

Description

ANORDNING FOR MEMBRANFILTRERING AV VATTEN MED FRIA RADIKALER OCH BACKSPOLNING MED LUFT OCH ULTRALJUD Beskrivning av uppfinningen Introduktion Nagra av de vanligare metoderna inom vattenfiltreringstekniken av idag är filtrering genom sand, mikrofiltrering genom sildukar eller aktivt kol och, ultrafiltrering genom s k ultrafiltermembran. DEVICE FOR MEMBRANE FILTRATION OF WATER WITH FREE RADICALS AND BACK RINSE WITH AIR AND ULTRASOUND Description of the invention Introduction Some of the more common methods in water filtration technology today are filtration through sand, microfiltration through screen cloths or activated carbon and ultrafiltration.

Det vatten, som skall behandlas kan harrora Than grundvattenkallor, insjoar eller olika typer av dammar eller vattendrag. Det kan ocksa vara recirkulerande vatten inom industrin for att bara namna nagra. The water to be treated can harrow Than groundwater sources, lakes or various types of ponds or streams. It can also be recirculating water in the industry just to name a few.

Van ligt forekommande kontaminationer som skall avlagsnas är organ iska suspensioner, humus, partiklar, fargkolloider, geler och syreforbrukande substans. Common contaminants to be removed are organic suspensions, humus, particles, paint colloids, gels and oxygen-consuming substances.

Forekommande problem Behandling av vatten med hjalp av sandfiltrerbadd innebar att reduktionen av partiklar och suspensioner inte blir tillrackligt stor utan att det ingaende vattnet forst flockas eller att klorering sker. Om sa icke sker avlagsnas endast partiklar, som är 10 pm eller stOrre. Common problems Treatment of water with the help of a sand filter bath meant that the reduction of particles and suspensions would not be large enough without the incoming water first flocking or chlorination taking place. If this does not happen, only particles that are 10 μm or larger are deposited.

Ett annat problem är att filterbehallaren tillsammans med sanden utgor en stor, tung och skrymmande del, som i sin tur medfOr att saval tillverknings-, lag-rings- och transportkostnaderna blir orimligt hoga i forhallande till sandfiltrets prestanda. Sandfilterbehallaren är van ligen cirkular, och har ett paronformat lateral- snitt, som medf6r att den inte kan vaggmonteras och pa grund darav upptar ett stort golvutrymme pa installationsplatsen. Another problem is that the filter container together with the sand forms a large, heavy and bulky part, which in turn means that both the manufacturing, storage and transport costs become unreasonably high in relation to the sand filter's performance. The sand filter container is usually circular, and has a pair-shaped lateral section, which means that it cannot be rock-mounted and therefore occupies a large floor space at the installation site.

Behandling av vatten med hjalp av mikrofiltrering innebar att alla partiklar, som är storre an filtermediets porer ansamlas pa filtermediets yta. Vid igensattning maste filtret pa nagot satt rengoras eller bytas ut mot ett nytt. Treatment of water with the aid of microfiltration meant that all particles larger than the pores of the filter medium accumulated on the surface of the filter medium. When clogging, the filter must be cleaned or replaced with a new one.

Behandling av vatten med ultrafiltermembran innebar att man avser att av- lagsna f6roreningar med ringa storlek, som t ex humus, fargkolloider eller andra sma partiklar av olika slag samt joner med lag molekylvikt. Vid tillampning av metoden kravs ofta en forfiltrering eftersonn det i praktiskt taget alla typer vatten ocksa 1 forekonnmer fororeningar av hogre storleksordning an sa. Metoden medfor ocksa en vattenforlust om c:a 25 till 35 %. Treatment of water with ultrafilter membranes meant that it was intended to remove contaminants of small size, such as humus, color colloids or other small particles of various kinds as well as ions with low molecular weight. When applying the method, a pre-filtration is often required, since practically all types of water also occur in pollutants of a higher order of magnitude. The method also entails a water loss of about 25 to 35%.

Behandling av vatten med aktivt kol i [Add eller i patroner kan endast tillarnpas f6r sma enheter och utg6r en metod for finfiltrering av redan forfiltrerat vatten. Treatment of water with activated carbon in [Add or in cartridges can only be adapted for small units and constitutes a method for fine filtration of already pre-filtered water.

Ett gram aktivt kol har en absorbtionsyta pa c:a 10 kvadratmeter, dar mycket sma partiklar accumuleras. Vid anlaggningar med stora kolbaddar blir det darigenom alltfOr kostsamt att byta kolmassan och ersatta den med ny sadan, vilket vid kontinuerlig drift normalt sker var 14:e dag. One gram of activated carbon has an absorption surface of about 10 square meters, where very small particles accumulate. In the case of plants with large coal baths, it thus becomes far too expensive to replace the coal mass and replace it with a new one, which during continuous operation normally takes place every 14 days.

Om man utgar ifran att vatten, som skall behandlas, inte är klorerat kan man konstatera att ovan angivna metoder forutom ultrafiltrering har gemensamt att fororeningarna ansamlas pa filtermediets yta, vilket far till foljd att denna belaggning pa ett eller annat maste avlagsnas med jamna mellanrum eller att filtermediet maste bytas ut mot ett nytt. If it is assumed that water to be treated is not chlorinated, it can be stated that the above-mentioned methods, in addition to ultrafiltration, have in common that the contaminants accumulate on the surface of the filter medium, which means that this coating must be removed at regular intervals or that the filter medium must be replaced with a new one.

En anledning till att ansamling av substans pa filtermedia sker är att vatten, som pressas in i ett filterhus och tacker hela filtermediets yta, saknar flagon namnyard rorelse narnnast intill den belaggning, som succesivt och utan hinder byggs upp pa filterytan. Detta kanda fenomen utgjorde anledningen till att membranfiltreringen borjade utvecklas, dar man pa bekostnad av vattenforluster och betydligt mer kostsamma anlaggningar an de tidigare alternativa metoderna betingade, dar man med hjalp av ett kontinuerligt strommande vattenskikt Over filtermediets yta skulle forhindra att denna belaggningsskiktning kunde forhindras. Med detta forfarande spolas c:a 30% av vattnet bort, vilket manga ganger blir for mycket eftersom flertalet vattenkallor har knapp tillforsel av vatten. One reason for the accumulation of substance on filter media is that water, which is forced into a filter housing and fills the entire surface of the filter media, lacks the slight movement of the nameplate almost adjacent to the coating, which is gradually and unobstructedly built up on the filter surface. This well-known phenomenon was the reason why membrane filtration began to develop, where at the expense of water losses and much more costly facilities than the previous alternative methods were required, where with the help of a continuously flowing water layer over the surface of the filter medium this coating layering could be prevented. With this procedure, about 30% of the water is flushed away, which is often too much because most water sources have a scarce supply of water.

Ovanstaende fakta är 'cant av fackmannen. The above facts are 'cant by those skilled in the art.

L6sningen pa ovannamda problem med hjalp av uppfinningen Foreliggande uppfinning i enlighet med patentkraven loser dels det problem, som galler ansamlingen av fororeningar pa filter och membranytor i olika filtreringssammanhang som är gemensamt f6r de metoder, som idag tillampas och dels det problemet, som innebar att fler an en behandlingsmetod maste tillgripas f6r behandling av vatten, som innehaller saval stora som sma f6roreningar. Uppfinningen omfattas aven av en process, som ager rum i en till uppfinningen h6rande anordning, dar reduktionen av kontanninationer sasonn organiska 2 suspensioner, partiklar, geler, fargkolloider och kemiskt lost syreforbrukannde substans avlagsnas pa ett satt, som medfor langre gaende rening an vad som kan erhallas med flagon tidigare kand metod. Beskrivningen av denna process aterfinns under rubriken "Funktions-och processbeskrivning" nedan. The solution to the above problems with the aid of the invention The present invention in accordance with the patent claims solves both the problem which concerns the accumulation of contaminants on filters and membrane surfaces in different filtration contexts which are common to the methods currently applied and the problem which meant that more a treatment method must be resorted to for the treatment of water which contains both large and small contaminants. The invention is also encompassed by a process which takes place in a device belonging to the invention, in which the reduction of contaminants such as organic suspensions, particles, gels, color colloids and chemically dissolved oxygen-consuming substance is deposited in a manner which results in longer purification than can be obtained with flagon previous bachelor method. The description of this process can be found under the heading "Function and process description" below.

Beskrivning av de till anordningen h6rande bestandsdelarna FOrfaringssattet enligt uppfinningen beskrivs med hjalp av en anordning, som aterfinns i Figur loch 2. Description of the components belonging to the device The method according to the invention is described with the aid of a device, which is found in Figure loch 2.

I nedanstaende beskrivning franses vissa smarre tekniska konstruktionsdetaljer sasom tatningar, infastningssatt, forskruvningar, kopplingsanordningar, godstjocklekar, forslutningar etc., som saknar betydelse for de grundlaggande processtekniska arrangemang, som galler sjalva uppfinningen som sadan. In the description below, certain clever technical construction details are fringed, such as seals, fasteners, fittings, coupling devices, wall thicknesses, closures, etc., which are irrelevant to the basic process technical arrangements which apply to the invention itself as such.

Filterhuset (1), som till alla delar bestar av stal, keramik eller nagot plast- material utgors av ett ratlinjart ror, forsett med botten och upptill forsett med en flans (2) med en cirkular falsning (3). The filter housing (1), which in all parts consists of steel, ceramic or some plastic material, consists of a straight-line rudder, fitted with the bottom and fitted at the top with a flange (2) with a circular seam (3).

I filterhuset (1) finns ett nnennbran (4). Detta nnennbran bestar av tva skikt. Det skikt som det obehandlade vattnet forst passerar genom, och som samtidigt utgor ett porost stodskikt for nastkommande skikt, kan besta av ett keramiskt porost material, eller en sintrad metall sasom exempelvis sintrad titan med en porstorlek av varierande ordning fran 20 pm till 0.1 pm, men foretradesvis 10 pm. Nastkommande skikt medstroms vattenflodesriktningen bestar av ett titanoxidskikt med en porositet, som kan varieras Than 20 pm till 0.1 mm, men fOretradesvis 10 pm. In the filter housing (1) there is an internal fire (4). This inner fire consists of two layers. The layer through which the untreated water first passes, and which at the same time constitutes a porous support layer for adjacent layers, may consist of a ceramic porous material, or a sintered metal such as sintered titanium with a pore size of varying order from 20 μm to 0.1 μm. but preferably 10 μm. Adjacent layers downstream of the water flow direction consist of a titanium oxide layer with a porosity which can be varied Than 20 μm to 0.1 mm, but preferably 10 μm.

Membranet (4) har en storre diameter nedtill an upptill. Dess lateralsnitt kannetecknas av en stympad kon vars sekant mot vertikalplanet kan varieras mellan 0 och 60 grader, men skall foretradesvis vara 20 grader for att dess yta skall kunna bli sa stor som mojligt. The membrane (4) has a larger diameter at the bottom than at the top. Its lateral section can be marked by a truncated cone whose secant to the vertical plane can be varied between 0 and 60 degrees, but should preferably be 20 degrees in order for its surface to be as large as possible.

Den nedre anden av detta membran (4) ar forsett med botten, som bestar av samma material som mantelytan. I dess ovre del har det en vinkelrat flans, som passar in i falsen (3) i filterhusets flans (2). The lower spirit of this membrane (4) is provided with the bottom, which consists of the same material as the mantle surface. In its upper part it has a perpendicular flange, which fits into the seam (3) in the flange (2) of the filter housing.

Inuti membranet (4) ar anbragt ett glasror (5), som ar 6ppet i !Ada andar. Det halls i sin ovre del fastklamt i en packbox (6). Inuti detta glasror (5) ar anbragt ytterligare ett glasror (7), vars botten är sluten och vars ovre anda nar upp till filterhusets lock (8) och kvarhalls av en i locket (8) anbragt packbox (9). Glasroret (7) 3 är upptill forsett med en forslutning (11). 1 della glasror (7) finns ett UV-lysror (12), vars kabel for stromforsorjning utloper genom forslutningen (11). 1 filterhusets lock (8) finns en horisontellt infast utloppsmuff (14), avsett att leda ut behandlat vatten smt inlopp f6r backspolningsvatten. Inside the membrane (4) is placed a glass tube (5), which is open in two spirits. It is held in its upper part clamped in a stuffing box (6). Inside this glass tube (5) is arranged a further glass tube (7), the bottom of which is closed and whose upper spirit reaches up to the filter housing cover (8) and is retained by a stuffing box (9) arranged in the lid (8). The glass tube (7) 3 is provided with a closure (11) at the top. In some glass tubes (7) there is a UV fluorescent tube (12), the power supply cable of which runs through the closure (11). In the filter housing cover (8) there is a horizontally fixed outlet socket (14), intended to lead out treated water and inlet for backwash water.

I den Ovre delen av filterhuset (1) finns ett anslutningsrOr (13) fOr inkom- mande vatten under filtreringsforloppet. Detta ror är vinklat, sa att vattentillstromningen blir tangentiell. In the upper part of the filter housing (1) there is a connecting pipe (13) for incoming water during the filtration process. This rudder is angled, so that the water inflow becomes tangential.

Stromningsforlopp vid normal filtrering. Se Figur 1. Flow profile during normal filtration. See Figure 1.

Vattnet pumpas in med hjalp av pumpen (18) till filterhuset (1) via inloppet (13), varefter det passerar genom membranfiltret (4). Dar passerar vattnet genom detta membranfilter (4) och leds darefter i nedatgaende riktning, och f6rs sedan upp mellan det yttre glasroret (5) och det inre glasroret (7) och leds slutligen ut ur det yttre glasrorets (5) ovre del till utloppet (14) for vidarebefordran via en flervags- ventil (10) som returvatten till tank eller pool. The water is pumped in by means of the pump (18) to the filter housing (1) via the inlet (13), after which it passes through the membrane filter (4). There the water passes through this membrane filter (4) and is then led in the downward direction, and is then carried up between the outer glass tube (5) and the inner glass tube (7) and finally led out of the upper part of the outer glass tube (5) to the outlet ( 14) for forwarding via a multi-way valve (10) as return water to the tank or pool.

Stromningsforlopp vid backspolning av membranfilter Se Figur 2. Backspolsvattnet pumpas med hjalp av pumpen (18) till inloppet (14) och fors vidare genom glasroret (5) i nedatgaende riktning. Fortsatter darefter i uppatgaende riktning mellan glasroret (5) och membranfiltret (4) fOr att slutligen avledas via flervagsventilen (10) till avlopp via ledningen (21). Flow profile during backwashing of membrane filter See Figure 2. The backwash water is pumped with the help of the pump (18) to the inlet (14) and is passed further through the glass tube (5) in the downward direction. Then continues in the upward direction between the glass tube (5) and the diaphragm filter (4) to be finally diverted via the multi-way valve (10) to the drain via the line (21).

Funktions- och processbeskrivning Under drift avges Iran UV-lysroret (12) ultraviolett straining inom ett vaglangdsomrade, om 175 till 260 nm men foretradesvis 254 nm. Functional and process description During operation, the Iran UV fluorescent lamp (12) ultraviolet straining is emitted within a wavelength range, of 175 to 260 nm but preferably 254 nm.

Da den ultravioletta stralningen traffar titanoxidskiktet frambringas fria radikaler i den dar passerande och kvarblivande mokrbmassan, som i sin tur astadkommer en process i vattnet dar nedbrytning av organ isk substans och aven kerniskt bundna organiska amnen ager rum. Denna process sker aven i vatutrymmet mel- Ian de !Dada glasroren och inom det vatutrymme som finns mellan glasroret (5) och membranet (4) med sitt titanoxidbelagda skikt. As the ultraviolet radiation hits the titanium oxide layer, free radicals are produced in the passing and remaining carbonaceous mass, which in turn creates a process in the water in which the decomposition of organic matter and even core-bound organic substances takes place. This process also takes place in the water space between the glass tubes and in the water space between the glass tube (5) and the membrane (4) with its titanium oxide-coated layer.

Denna process fungerar pa sa satt att vissa atomer och molekyler mister en resp. flera elektroner, och darmed efterstravar att ersatta forlusten genonn att uppfanga elektroner fran andra atomer och/eller molekyler som i sin tur forfar pa 4 samma satt osv. Det bildas en kedjereaktion, som gar snabbt, varvid kontaminationer av olika slag reduceras. Nar en fri radikal patraffar en antioxidant, bildas det inte en ny fri radikal. Kedjereaktion avstannar men antioxidanten har samtidigt blivit forbrukad. This process works in such a way that certain atoms and molecules lose a resp. several electrons, and thus strives to replace the loss by capturing electrons from other atoms and / or molecules which in turn proceed in the same way, etc. A chain reaction is formed, which goes quickly, whereby contaminations of various kinds are reduced. When a free radical hits an antioxidant, a new free radical is not formed. Chain reaction stops but the antioxidant has been consumed at the same time.

Eftersom de fria radikalema maste omintetgOras innan det renade vattnet tas i bruk ingar det i uppfinningen att en antioxidant under drift doseras in i vattnet innan det utmynnar ur utloppsledningen, som är ansluten vid utloppet (14). FOrdenskull ar anordningen forsedd med en nippel (16), till vilken en doseringsanordning skall kunna anslutas i syfte att tillfora en antioxidant i vatutrymmet under det ku- pade filterhusets lock (8). Since the free radicals must be annihilated before the purified water is used, it is in the invention that an antioxidant is metered into the water during operation before it empties from the outlet line, which is connected at the outlet (14). For this reason, the device is provided with a nipple (16), to which a dosing device must be able to be connected in order to supply an antioxidant in the water space under the lid of the cupped filter housing (8).

Till skillnad fran de i inledningen anforda metoderna, dar filter- eller membranbelaggningar inte avlagsnas kontinuerligt, som innebar kannbara kostnader fororsakade av standigt aterkommande filterbyten eller markbara vattenforluster p.g.a. fortatade backspolningsintervaller, medger detta forfarande att detta forfa- rande undviker belaggningar pa membranet med en minimal bekostnad av vattenforlust. Flodesarrangennanget enligt anordningen franngar av Skiss 1 med hanvisningar enligt nedan. Unlike the methods stated in the introduction, where filter or membrane coatings are not removed continuously, which entailed significant costs caused by constantly recurring filter changes or noticeable water losses due to repeated backwash intervals, this method allows this procedure to avoid coatings on the membrane with a minimal cost of water loss. The river arrangement according to the device follows from Sketch 1 with male instructions as below.

Syftet med glasroret (5) är att astadkomma tva stromningsvagar innanfor det membranet (4), dar den ena gar genom glasroret (5) och den andra mellan glasro- ret (5) och det membranet (4), varvid vattnets stromningshastighet fordubblas och dess tjocklek forminskas till haften samt att vattnet i dessa [Ada stromningsomradena bestralas med det ultravioletta ljuset samtidigt. The purpose of the glass tube (5) is to provide two flow waves within that membrane (4), one passing through the glass tube (5) and the other between the glass tube (5) and the membrane (4), doubling the flow rate of the water and its thickness is reduced to the sea and that the water in these [Ada flow areas is irradiated with the ultraviolet light at the same time.

Da vattnet blir alit renare under stromningsforloppets bestralningskede kommer uv-stralningens skuggzoner att succesivt avta i antal, vilket innebar att man i allt okande grad under vattenstrommens passage erhaller en avdodning av eventuellt ej avlagsnade mikroorganismer inkluderande bacteriae och virus mm, da vattnet i slutfasen passerar genom glasroret (5). Dessa omintetg6rs av enbart uvstralningen genom att deras DNA-molekyl knacks. As the water becomes alit cleaner during the irradiation phase of the flow process, the shadow zones of the UV radiation will gradually decrease in number, which meant that to an increasing degree during the passage of the water flow a killing of any non-deposited microorganisms including bacteria and viruses etc. is obtained. glass tube (5). These are destroyed by radiation alone by knocking out their DNA molecule.

Forhallandet mellan diametern pa glasroret (10) och glasroret (5) skall vara fran 1:2 till 1:4 men foretradesvis 1: 3. Forhallandet mellan diametern pa glasroret (5) och membranet (4) skall vara fran 1:1.2 till 1:8 men foretradesvis 1: 1.3. The ratio between the diameter of the glass tube (10) and the glass tube (5) should be from 1: 2 to 1: 4 but preferably 1: 3. The ratio between the diameter of the glass tube (5) and the membrane (4) should be from 1: 1.2 to 1 : 8 but preferably 1: 1.3.

Glasroret (5), som är oppet i !Dada andar, bringar vattnet att stromma langre stracka inom det UV-bestralade omradet i syfte att minimera upptradande skuggzoner da vattnets kontaminationer huvudsakligen utgores av substanser, som astadkommer turbiditet. The glass tube (5), which is open in dead spirits, causes the water to flow longer distances within the UV-irradiated area in order to minimize emerging shadow zones as the contaminations of the water mainly consist of substances which cause turbidity.

Reng6ring av membranfiltret med hjalp av ultraljudsenhet I och med att flervagsventilen (10) omstalls till backspolning startas ultraljudsenheten (22), vilket far till foljd att den drankbara givaren 0 avger ultraljud till membranfiltret, som avlagsnar flertalet av partiklar, som ansamlats pa membranfiltrets yta och i dess porer. Samtidigt startas luftkompressorn (20) varvid luft inblases i backspolningsvattnet, som likaledes pressas ut genom membranfiltret. Cleaning the diaphragm filter by means of ultrasonic unit As the multi-way valve (10) is switched to backwashing, the ultrasonic unit (22) is started, which causes the drinkable sensor 0 to emit ultrasound to the diaphragm filter, which removes most of the particles accumulated on the diaphragm filter in its pores. At the same time, the air compressor (20) is started, whereby air is blown into the backwash water, which is also forced out through the membrane filter.

Detta är kant av fackmannen. 20 25 6 This is the edge of the artisan. 20 25 6

Claims

CLAIMS 1. Device for decomposition and removal of contaminants such as organic suspensions, humus, particles, gels, color colloids and knowledgeable oxygen-consuming organic matter etc. from water, may be characterized by comprising:

A filter housing (1) with an inlet part comprising an inlet pipe (13) adapted to lead polluted water into the filter housing (1) and an outlet part comprising an outlet stream. (14) adapted to divert purified water than filter housing (1); A porous membrane (4) comprising a bottom and a mantle surface arranged inside the inlet part of the filter housing (1), and which has a large diameter at the bottom and at the top and which thereby forms the shape of a truncated cone; A first glass tube (5) tipped in said spirit and arranged in the inlet part around the center of the filter housing (1) inside the membrane (4), the inlet part being in fluid communication with the outlet part through the glass tube (5); - a second glass tube (7) with closed bottom arranged inside the first glass tube (5); and 4. a UV fluorescent tube (12) housed in the second glass tube (7) and adapted to emit straining of ultraviolet light to strike a layer present on the membrane (4), to produce free radicals, which in their fur lead to combustion and decomposition of said contaminants in the water passing through the irradiation area, the lower end of the glass tube (5) being arranged near the bottom of the membrane (4) to extend the water-flowing Than membrane (4) of the water to the outlet part.

Device according to claim 1, further comprising an air compressor (20) arranged in connection with the outlet part of the filter housing (1) and adapted to supply air to the water when the device is backwashed and an ultrasonic unit (22) adapted to deliver ultrasound to the membrane (4) to effect cleaning of the surface of the membrane (4) and its pores.

Device according to claim 1 or 2, further comprising a dosing pump arranged in connection with the outlet part of the filter housing (1) and adapted to supply an antioxidant to the water to stop the production of free radicals. 7

Device according to any one of the preceding claims, wherein the lateral section of the membrane (4) is inclined towards the vertical plane at an angle between 0 and 60 degrees, preferably 20 degrees.

Device according to any one of the preceding claims, wherein the layer applied to the membrane (4) consists of sintered titanium oxide.

Device according to any one of the preceding claims, wherein the UV fluorescent lamp (12) is adapted to emit ultraviolet light straining with a wavelength between 175 and 260 nm, preferably 254 nm.

Device according to any one of the preceding claims, wherein the inlet pipe (13) is arranged at an angle to the side cradle of the filter housing (1) in order to provide tangential water flow towards the membrane (4).

A method for decomposing and removing contaminants such as organic suspensions, humus, particles, gels, color colloids and chemically oxygen-consuming organic matter etc. from water, comprising the following steps: 1. directing the water to be purified into a filter housing (1) with an inlet part via an inlet pipe (13); 2. passing the water through a porous membrane (4), comprising a bottom and a mantle surface arranged inside the inlet part of the filter housing (1), and which has a larger diameter at the bottom than at the top and thereby forms the shape of a truncated cone; 3. passing the water through a first glass tube (5) tipped in [Ada spirits and arranged in the inlet part around the center of the filter housing (1) inside the membrane (4), the inlet part being in fluid communication with an outlet part of the filter housing (1) through the glass tube ( 5); and 4. directing the water out of the outlet portion via an outlet tube (14), the water being irradiated with ultraviolet light from a UV fluorescent tube (12) housed in a second glass tube (7) with a closed bottom and arranged inside the first glass tube below its passage from the membrane (4) to the outlet part, whereby the ultraviolet light is allowed to strike a layer present on the membrane (4), in order to repel free radicals, which in turn leads to combustion and decomposition of said pollutants in the water passing through the irradiation tube. , and 8 wherein the flow path of the water from the membrane (4) to the outlet part is extended by arranging the lower end of the glass tube (5) near the bottom of the membrane (4).

The method of claim 8, further comprising the step of performing a backwash to remove coatings than outer surface of the membrane (4) while supplying air than an air compressor (20) disposed adjacent the filter housing outlet (1) and delivering ultrasound to the membrane (4) by means of an ultrasonic device (22).

The method of claim 8 or 9, further comprising the step of adding an antioxidant to the water to stop the generation of free radicals.

A method according to any one of claims 8 to 10, wherein the water to be purified is led in at an angle to the side cradle of the filter housing (1) to provide tangential water flow towards the membrane (4). 9