Oxidation reactor

Abstract

The present invention relates to an oxidation reactor for water purification, wherein the oxidation reactor (10) comprises a water inlet (2), an oxidizing agent injector (15) configured to supply an oxidizing agent to the oxidation reactor (10), and a filler material (12) arranged inside the oxidation reactor (10); whereby a gaseous cushion (11) from the oxidizing agent is formed above the water level (WL1) inside the oxidation reactor (10), and whereby water entering the oxidation reactor (10) is brought into contact with said gaseous cushion (11) and the filler material (12). The present invention further relates to a water purification system and method.

Description

[0001] OXIDATION REACTOR

[0002] Technical Field

[0003] The present invention generally relates to an oxidation reactor for water purification, and a water purification system comprising said oxidation reactor. The invention also relates to a water purification method.

[0004] Background

[0005] Water may comprise different types of contaminants. To remove such different types of contaminating particles or dissolved substances, water may be pressurized, often using either a hydrophore, or alternatively a hydropress, followed by filtering the water through a plurality of filters.

[0006] A hydropress is a closed tank with a built-in air cushion (membrane) made of rubber. When the water is pumped in, the membrane is compressed until a predetermined pressure is reached, whereby the pump stops. When draining the water from the hydropress, the pressure in the hydropress decreases, whereby the water pump again starts to maintain the predetermined pressure. A hydropress is therefore only used to create a preset pressure in pipe lines connected to the hydropress. However, a hydropress used to treat water to produce for instance drinkable water must be further connected with filter media, i.e. a carbon filter, arranged downstream of the pressure vessel to obtain drinkable water.

[0007] A hydrophore is a closed tank filled with air. When a water pump pumps water into the hydrophore, the air contained therein is compressed and forms an air cushion above the water surface. The more the pump manages to compress the air cushion, the higher pressure is achieved inside the hydrophore. In a well-functioning hydrophore, the water is sprinkled, or showered, on top of or in the formed air cushion of the hydrophore, thereby achieving oxygenation of the incoming water. If the incoming water contains oxidizable impurities such as iron and manganese, these can be precipitated in particulate form. However, it may be difficult to obtain sufficient oxidation of the contaminants.

[0008] Water may contain various impurities, such as iron, manganese, pharmaceutical residues, pathogens such as bacteria, and / or heavy metals. Such impurities increase the COD (Chemical Oxygen Demand) of the water. Heavy metals may affect the environment and / or humans exposed to the heavy metal compounds, and iron and manganese must not be present in drinking water, or at least not be present above established threshold values.

[0009] Hence, there is a need to provide improved water purification systems.

[0010] Summary

[0011] It is accordingly an object of the invention to eliminate or alleviate at least some of the problems or drawbacks referred to above. The present invention is based - inter alia - on the idea that an increased contact surface between the water to be purified and a gaseous oxidizing agent increases oxidation efficacy of contaminants present in the water. By supplying water into a gaseous cushion formed from the oxidizing agent, water is spread over the gaseous cushion rather than having a gaseous oxidizing agent supplied into the water forming e.g. air bubbles in the water. This results in that the oxidizing agent, such as oxygen, is brought into contact with an enlarged water surface exposing contaminants to the oxidizing agent. In known oxidation reactors for water purification, the contact surfaces between water and oxidizing agent are limited depending on the volume of the water, since the oxidizing agent is supplied into the water. The present invention inverts the relationship between the gaseous oxidizing agent and water, resulting in an increased water surface area. The oxidation reactor according to the present invention also operates at a pressure deviating from ambient pressure (i.e. either an over pressure or negative pressure), which further enlarges the water surface area.

[0012] In a first aspect, there is provided an oxidation reactor for water purification, wherein the oxidation chamber comprises a water inlet, an oxidizing agent injector configured to supply an oxidizing agent to the oxidation reactor, and a filler material arranged inside the oxidation reactor. The filler material is arranged above a water level inside the oxidation reactor whereby a gaseous cushion from the oxidizing agent supplied from the oxidizing agent injector is formed above the water level inside the oxidation reactor, and whereby water entering the oxidation reactor is brought into contact with said gaseous cushion and the filler material.

[0013] This oxidation reactor is beneficial since it provides an optimized, increased, contact surface between the gaseous cushion and the water supplied to the oxidation reactor. Hence, contaminants present in the water to be purified will have an increased contact surface with the oxidizing agent in the gaseous cushion. In addition, the filler material increases the retention time of the water in the oxidation reactor, since water will form a water film on the outer surface of the filler material, and slowly trickle trough the filler material. This increases the contact time between the oxidizing agent and the contaminants in the water, which further enhances the oxidation reaction and thereby provides for efficient and high quality purification. When contaminants are oxidized, they precipitate and can easily be removed from the liquid water phase. The oxidation reactor takes up a small amount of space and is easy to install. Moreover, the number of filters arranged downstream of the oxidation reactor can be decreased.

[0014] In a first embodiment, the water inlet is arranged above the filler material.

[0015] In another embodiment, the oxidation reactor is sealed, whereby the oxidation reactor operates at an overpressure. An overpressure has proven beneficial for enhancing the oxidation process of contaminants in the water entering the oxidation rector.

[0016] In another embodiment, the oxidation reactor further comprises an outlet arranged in a lower portion of the oxidation reactor.

[0017] The oxidation reactor may comprise an outlet arranged below the water level inside the oxidation reactor, whereby the water level prevents oxygen in the gaseous cushion from exiting from the oxidation reactor.

[0018] In one embodiment, the oxidizing agent injector is arranged in connection with the water inlet or is connected directly to the oxidation reactor.

[0019] In one embodiment, the oxidation reactor further comprises a water distributor connected to the water inlet and being arranged above the filler material. This is beneficial since the water distributor may spread and sprinkle the incoming water evenly on top of the filler material. This in turn further improves the purification of the water.

[0020] The filler material may be made from irregularly entangled filaments and / or the filler material may be made from a material having a rugged surface. This is advantageous in that it prolongs the time that the water is upheld in the oxidation reactor, and therefore the process of oxidation of impurities becomes efficient. An increased surface area formed from either entanglements of filaments or threads, or a rugged surface will also increase the contacts surface between the oxidizing agent and the water, and thus make the oxidation process more effective.

[0021] Additionally or alternatively, the filler material is provided in the form of regularly arranged filaments.

[0022] In one embodiment, the oxidizing agent supplied by the oxidizing agent injector is oxygen supplied as a gas being air, oxygen O2, ozone O3, or a combination thereof. These forms of oxygen have proven efficient in tests performed of the water purification system disclosed herein. Ozone has proven especially efficient for purification of water comprising heavy metals. When the water purification system is injected with ozone, mineralization of the heavy metals present in the incoming water takes place, and the mineralised heavy metal particles may be separated from the water for instance using a filter or draining them from the bottom of the second water tank after sedimentation.

[0023] In another embodiment, the oxidation rector comprises a pressure regulating means. The pressure regulating means may be used to establish an over pressure or negative pressure in the oxidation reactor. Such a pressure, deviating from an ambient atmospheric pressure further increases the water surface area and thus makes the oxidation process, an thus the purification process, more efficient.

[0024] In a second aspect, there is provided a water purification system comprising a first water tank in the form of an oxidation reactor as described above, and a second water tank being in fluid communication with the first water tank. This water purification system is beneficial since it efficiently and easily can purify water comprising impurities such as heavy metals, per- and polyfluoroalkyl substances (PF AS), pathogens, pharmaceutical residues, iron and / or manganese. The system also efficiently decreases the COD (Chemical Oxygen Demand) of the water entering the system. The first water tank is the oxidation reactor referred to above and is associated with the same advantages as described above. Precipitated impurities may easily be separated from the water phase with the water purification system. The water purification system is easy to install and cost effective.

[0025] In one embodiment, the first water tank is at least partly arranged inside the second water tank and at least partly below a water level WL2 of the second water tank, or the second water tank is at least partly arranged inside the first water tank and at least partly below a water level WLI of the first water tank. This provides for a water purification system taking up a small amount of space. It also facilitates the regulation of the water levels within the first and second water tanks.

[0026] In one embodiment, the first water tank is connected to the second water tank through a conduit. Preferably, the conduit is provided with a pump. Preferably, the conduit is connected to the oxidation reactor below the water level inside the oxidation reactor and connected to the second water tank above a water level in the second water tank. Additionally or alternatively, the first water tank may be provided with alternative or additional openings connecting the first water tank with the second water tank.

[0027] In a further embodiment, the second water tank comprises a water outlet.

[0028] In another embodiment, a water level WLI of the first water tank is lower than a water level WL2 of the second water tank.

[0029] In yet another embodiment, the first water tank and the second water tank forms a sealed system, where the second water tank is sealed around the first water tank, and in which the first water tank and the second water tank are in fluid communication with each other; or the first water tank and the second water tank forms a non-sealed system, where the second water tank comprises an open top portion or is provided with at least one aperture above a second water tank water level, and in which the first water tank and the second water tank are in fluid communication with each other. In the embodiment where the system is a sealed system, the water purification system forms a hydropress. In the embodiment where the system is a non-sealed system, the first and second water tanks are arranged as communicating vessels and the second water tank is a non-pressurised vessel. In this case, the second water tank is provided with an opening or valve such that it is a non-pressurised tank.

[0030] In one embodiment, the first water tank and the second water tank forms a sealed system, wherein the first water tank is sealed around the second water tank, and in which the first water tank and the second water tank are in fluid communication with each other; or the first water tank and the second water tank forms a non-sealed system, wherein the first water tank comprises at least one top opening, and in which the first water tank and the second water tank are in fluid communication with each other.

[0031] In a further embodiment, the second water tank is provided with a recirculation pump configured to pump water through a return pipe from the second water tank to the water inlet. This may return water to recirculate one more through the first water tank and thus increase the degree of purification of the water.

[0032] In a third aspect, there is provided a water purification method comprising the steps of providing a first water tank being the oxidation reactor described above, supplying an oxidizing agent to the oxidation reactor using the oxidizing agent injector, whereby a gaseous cushion is formed above the water level WLI inside the oxidation reactor. The method further comprises supplying water through the water inlet of the oxidation reactor, and allowing the water to flow through the filler material in the oxidation reactor, whereby the water entering the oxidation reactor is brought into contact with said gaseous cushion and the filler material. This method has the same advantages as presented in relation to the water purification system and the oxidation reactor above.

[0033] In one embodiment, the method comprises a step providing a second water tank being in fluid communication with the oxidation reactor. In this way, a water purification system is formed.

[0034] In a further embodiment, during the supplying step the oxidizing agent is supplied either in connection with the water inlet or directly to the oxidation reactor.

[0035] In another embodiment, the method further comprises a step of regulating the oxidizing agent injector, the water inlet and a water outlet such that a water level of the oxidation reactor becomes lower than a water level of the second water tank, or such that a predetermined pressure is reached in the oxidation reactor. This is beneficial since a predetermined pressure may affect the effectiveness of the oxidation within the oxidation reactor.

[0036] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein.

[0037] All references to "a / an / the [element, device, component, means, step, etc.]" are to be interpreted openly as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

[0038] A reference to an entity being “designed for” doing something, or “capable of’ doing something in this document is intended to mean the same as the entity being “arranged for”, “configured for” or “adapted for” doing this very something, and vice versa.

[0039] Brief Description of the Drawings

[0040] Fig. 1 A illustrates an oxidation reactor according to one embodiment of the invention;

[0041] Fig. IB illustrates an oxidation reactor according to one embodiment of the invention;

[0042] Fig. 2 shows a water purification system comprising the oxidation reactor according to one embodiment of the invention; Fig. 3 shows a water purification system comprising the oxidation reactor according to another embodiment of the invention;

[0043] Fig. 4 shows a flow chart of a method for water purification according to one embodiment of the invention;

[0044] Fig. 5 shows a water purification system comprising the oxidation reactor according to another embodiment of the invention;

[0045] Fig. 6 shows a water purification system comprising the oxidation reactor according to another embodiment of the invention; and

[0046] Fig. 7 shows an enlarged portion of a filler material disclosed herein.

[0047] Detailed Description

[0048] Embodiments of the invention will now be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

[0049] Figs. 1 A and IB show a water tank 10. The water tank 10 described herein is an oxidation reactor 10, also referred to as an oxidation chamber 10. As shown in Figs. 1 A and IB, the oxidation chamber 10 is provided with a water inlet 2. The water inlet 2 has an optional water inlet valve 2’. The water inlet valve 2’ can be regulated, and is thus configured to regulate the amount of water supplied to the water tank 10. Further, the water tank 10 has an outlet 17. In Figs. 1 A and IB, the outlet 17 is arranged at the bottom of the water tank 10.

[0050] The oxidation chamber 10 comprises a filler material 12. The filler material 12 is arranged inside the oxidation chamber 10. The filler material 12 may have various shapes and configurations. Preferably, the filler material 12 is formed from a plurality of entangled filaments or irregular threads. Hence, the filler material 12 has a plurality of openings allowing water to flow or trickle through the filler material 12. The filler material 12 is porous to allow water to flow downwards through the filler material 12. The filler material 12 may be formed from a material, such as the entangled filaments, having a rugged surface. Alternatively or additionally, the filler material 12 may comprise wheel or cog shaped filler material pieces, either provided as unattached filler material pieces or being attached to the water tank 10.

[0051] Alternatively or additionally, the filler material 12 is provided in the form of plates arranged in a stack inside the oxidation chamber 10.

[0052] Alternatively or additionally, the filler material 12 is attached to an inside surface of the oxidation chamber 10.

[0053] Alternatively or additionally, the filler material 12 is formed from a bath sponge like material.

[0054] The filler material 12 provides a surface area onto which a thin water film is formed when water is brought into contact with the filler material 12.

[0055] Preferably, the oxidation chamber 10 has an openable top, which can be opened to for instance exchange the filler material 12 if needed. Hence, the filler material 12 is preferably removable from the oxidation chamber 10. The oxidation reactor 10 may be sealed as shown in Figs. 1 A and IB, or it may comprise at least one optional top opening (shown in Fig. 5) to form a non-sealed oxidation reactor 10.

[0056] The oxidation reactor 10 further comprises an oxidizing agent injector 15, configured to supply an oxidizing agent to the oxidation reactor 10. The oxidizing agent may be oxygen, preferably supplied as a gas being air, oxygen O2, ozone O3, or a combination thereof. Alternatively, other oxidizing agents may be injected. In Fig. 1 A, the oxidizing agent injector 15 is arranged in direct connection with the oxidation reactor 10. The oxidizing agent injector 15 may also in an alternative embodiment be arranged in connection with the water inlet 2, as shown in Fig. IB. The oxidation reactor 10 of Fig. IB is identical with the oxidation reactor 10 shown in Fig. 1A, except from the placement of the oxidizing agent injector 15.

[0057] Alternatively or additionally, the oxidation reactor 10 is provided with means to decrease the pressure inside the oxidation chamber 10, such that a negative pressure can be obtained within the oxidation chamber 10.

[0058] Further, the water tank 10 in Figs. 1 A and IB is provided with an optional ventilating valve 16. An oxidation chamber water level WLI is also indicated in Figs. 1 A and IB. The filler material 12 is entirely arranged above the oxidation chamber water level WLI. Since the oxidation chamber water level WLI is below the filler material 12, the filler material 12 is surrounded by the oxidizing agent provided to the water tank 10.

[0059] In an alternative embodiment not shown herein, the filler material 12 is arranged partly above and partly below the oxidation chamber water level WLI. Optionally, the water inlet 2 is further coupled to a water distributor 13, as shown in Figs. 1 A and IB. The water distributor 13 spreads water entering the water tank 10 over the filler material 12, as indicated with the rounded arrows in Figs. 1 A and IB.

[0060] The oxidation chamber 10 has a vertical extension with a top and a bottom. Hence, the oxidation chamber 10 has an oxidation chamber upper portion 10a, an oxidation chamber middle portion 10b, and an oxidation chamber lower portion 10c. The oxidation chamber middle portion 10b comprises the filler material 12. However, the filler material 12 may also extend into the oxidation chamber upper portion 10a and / or the oxidation chamber lower portion 10c. The filler material 12 is arranged above the oxidation chamber water level WLI in the vertical extension. The filler material 12 may fill at least ’A of the volume inside the oxidation reactor 10.

[0061] Figs. 1 A and IB further show that the water inlet 2 and the optional water distributor 13 are arranged in the oxidation chamber upper portion 10a. This is preferable since this facilitates the water entering the water tank 10 to be distributed on top of the filler material 12.

[0062] The ventilating valve 16 in Figs. 1 A and IB is coupled to the oxidation chamber lower portion 10c. Further, the oxidation chamber lower portion 10c is provided with the outlet 17, which may be a ventilating valve 17 or a bottom opening 17. The outlet valve 17 or bottom opening 17 allows water to exit the oxidation chamber 10.

[0063] The oxidation chamber 10 is a sealed tank. In Figs. 1 A and IB, the oxidation chamber 10 is sealed by its side walls, the openable top and by the bottom comprising the closable outlet valve 17. In other embodiments, where the oxidation chamber 10 comprises a bottom having an opening 17 at the outlet, the oxidation chamber 10 is sealed during use by its side walls, the openable top and the oxidation chamber water level WLI. Hence, the gaseous cushion 11 is sealed inside the oxidation chamber 10 during use, and is maintained within the oxidation chamber 10. The concentration of the oxidizing agent may therefore be kept constant. This is of importance for the efficiency of the water purification, but also to avoid polluting the environment with oxidizing agents such as ozone. An ozone leak from the tank 10 would be damaging to the environment.

[0064] Preferably, the water tank 10 has a longitudinal, vertical, height in the range of 0.5 to 3 meters, preferably of about 1.5 meters. The water tank 10 may have a width of about 10 to 70 cm, preferably 20 to 60 cm, preferably about 36 cm. In order to provide a water tank 10 which may treat a larger volume of water per minute, the water tank 10 may simply be increased in height. Hence, the water tank 10 may be provided for different ranges of flow volumes, without taking up additional space on the ground.

[0065] The function of the oxidation reactor 10 will now be further explained. The general principle of the oxidation reactor 10 is that contaminated water entering the oxidation reactor 10 will be brought into contact with an oxidizing agent, which will oxidise the contaminants in the water. Oxidation of contaminants causes the contaminants to precipitate. Since precipitates are particulate matter, it can be easily separated from the water liquid phase. The filler material 12 has a large surface area, onto which the water forms a thin water film. This both increases retention time for the water within the oxidation reactor, but also increases and optimizes the contact surface between the water and the oxidizing agent.

[0066] Figs. 1 A and IB show the oxidation reactor 10 after it has been filled with water and after the oxidizing agent injector 15 has been activated. Water is supplied to the water tank 10 through the water inlet 2, and an oxidizing agent is supplied by the oxidizing agent injector 15. The amount of water and oxidizing agent may be regulated. For instance, the amount of water supplied may be about 15 L / minute. In addition, the outlet 17 may also be regulated. By regulating the water inlet 2, the oxidizing agent injector 15 and the outlet 17, a predetermined oxidation chamber water level WLI is reached within the water tank 10. The regulation of the water inlet 2, and / or the oxidizing agent injector 15, and / or the outlet 17 also regulates the pressure within the oxidation reactor 10. Since the oxidation chamber 10 is sealed, addition of water through the inlet 2 and an oxidizing agent through the injector 15 will increase the pressure within the oxidation chamber 10.

[0067] When the oxidizing agent is injected into the oxidation chamber 10, the volume above the oxidation chamber water level WLI is filled with the oxidizing agent. Hence, an air cushion or gaseous cushion 11 is formed inside the oxidation chamber 10. The gaseous cushion 11 surrounds the filler material 12. In this way, when water enters the oxidation chamber 10 through the water inlet 2, the water is spread on top of the filler material 12, and over the air cushion 11 formed inside the oxidation chamber 10. Hence, the water supplied to the water tank 10 will be brought into contact with the gaseous cushion 11 and the filler material 12. The supplied water will cling to the surface area of the filler material 12 and cover the surface area of the filler material 12 with a thin water film. Said water film may for instance be 0.2 mm thick. The large surface area provided by the filler material 12 gives the water an increased retention time in the oxidation chamber 10. In addition, the filler material 12 provides an increased contact surface between the water and the oxidizing agent present in the oxidation chamber 10. The increased and optimized contact surface between the oxidizing agent and contaminants present in the water allows for an improved and more efficient purification of the water. The oxidizing agent will react with contaminants, such as heavy metals, pharmaceutical residues, pathogens, PFAS, Manganese and / or Iron present in the water entering the water tank 10. When the contaminants react with the oxidizing agent, the contaminants oxidise which in turn causes the contaminants to precipitate. It has also been found that if ozone is used as the oxidizing agent, the water also becomes disinfected.

[0068] The oxidation chamber 10 herein provides an oxidation chamber 10 where there is an excess of oxygen atoms compared to non-treated water. In other known oxidation chambers, the systems are often submerged, i.e. a gaseous oxidizing agent such as air is injected into the water. Such a system results in a chamber having an excess of non-treated water compared to oxygen atoms. This oxidation chamber 10 operated in an opposite manner, spreading water over the gaseous cushion 11.

[0069] The treatment chamber upper portion 10c is sealed. The oxidation chamber water level WLI prevents the oxidizing agent from escaping the oxidation chamber 10 through the bottom opening 17. Alternatively, the valve outlet 17 is sealed and prevent both water and the oxidizing agent from escaping the water tank 10. Preferably, the valve outlet 17 and the water inlet 2 are regulated in such a way that the oxidation chamber water level WLI is maintained at a constant level within the water tank 10.

[0070] Hence, during use, the oxidation chamber 10 is sealed by the oxidation chamber water level WLI, its side walls and the sealed openable top. The oxidizing agent supplied by the oxidizing agent injector 15 will therefore remain in the water tank 10. The oxidizing agent supplied to the oxidation reactor 10 will increase the pressure within the oxidation chamber 10. Since gas is compressible, the gaseous cushion 11 will be compressed as additional oxidizing agent is injected into the water tank 10. If the outlet valve 17 is opened, water will be forced out from the oxidation chamber 10 as a result of the gaseous oxidizing agent expanding.

[0071] In the event the oxidation chamber water level WLI would drop below the ventilating valve 16, the ventilating valve 16 is opened. This will lower the pressure inside the water tank 10 such that the predetermined oxidation chamber water level WLI may be re-established. Further, the oxidation reactor 10 may comprise a separate pressure regulating means, which is configured to either elevate or decrease the pressure within the oxidation reactor 10. Water entering the oxidation chamber 10 may therefore be exposed to a negative pressure or an overpressure. The provision of a negative pressure or overpressure further improves the water purification process by making the oxidation reaction of the contaminating particles in the water more efficient.

[0072] Hence, purification of the water entering the water tank 10 is based on the idea that oxidation will precipitate contaminants present in the water. Water enters the water tank 10 through the water inlet 2, and is distributed, preferably by the water distributor 13, over the filler material 12. The oxidizing agent injection 15 supplies an oxidizing agent to the water tank 10, and a gaseous cushion 11 is formed in the water tank 10 above the predetermined oxidation chamber water level WLI. Water will trickle through the filler material 12 and the gaseous cushion 11, and form a thin water film on the surface area of the filler material 12. The water is allowed to drip over the gaseous cushion 11 and the filler material 12. The large surface area of the filler material 12 provides an increased contact surface between the oxidizing agent and the contaminants in the water. Oxidation between the contaminants and the oxidizing agent occurs, causing the contaminants to precipitate.

[0073] In an oxidation reactor, an oxidation occurs between oxygen, being negatively charged, and positively charged components, such as metals. In other words, various molecules can react with oxygen through oxidation. Metals or heavy metals dissolved in water may react with oxygen and form an oxidation product which is easily separated from the water, either by sedimentation or filtration. In state of the art oxidation reactors, oxygen is supplied by blowing air / oxygen into a bottom portion of a vessel filled with water comprising heavy metal ions or other materials that one wishes to oxidate. The air / oxygen is blown into the vessel by a diffusor. The air / oxygen is in gaseous form and will therefore flow and rise up towards the water surface after being supplied trough the diffusor. The diffusors are used to distribute the gas into small bubbles to increase the contact area between gas and water since small spherical bubbles have a larger surface area than larger spherical bubbles at the same total volume of gas.

[0074] The pressure affects the size of the spheres, and when they rise towards the surface the pressure decreases, causing the bubbles to grow larger. The amount of oxygen however remains the same, or will decrease as the oxidation process progresses and oxygen is consummated or dissolves in the water. The spherical bubbles rising and growing in size cause turbulence and movement in the water. Hence, the spherical gas bubbles form the contact area between oxygen and water. The state of the art vessel is submerged into the water, resulting in that the oxidation takes place below the water surface.

[0075] The present invention is based on this knowledge, but the oxidation reaction does not take place in a submerged reactor. Oxygen is dissolved above the water level, while the oxidation takes place either in the water film formed on top of the filled material 12 or when the entering water reaches the eater level in the oxidation reactor 10. The contact between the gas comprising oxygen and water mainly occurs above any potentially water level present. This is further described with reference to Fig. 7 below. Contact between the gas and the water can occur at ambient pressure, overpressure or underpressure (subatmospheric pressure).

[0076] The water in the oxidation reactor 10 is spread over the filler material 12, and referred to as a surface enlarger 12. With the aid of gravity, the water will flow over the surface enlarger 12 and form a thin coating of water on top of the filler material 12. The flow and movement inside the oxidation reactor 10 is turbulent, causing different portions of the water to be exposed to the surrounding oxidation agent supplied by the oxidizing agent injector 15. The gaseous oxidizing agent may be supplied with an injection blower. By forcing the gaseous oxidizing agent into movement through thermal forces, or with an injection blower, the amount of oxygen coming into contact with the surface of the water present on the filler material 12. This results in that more oxygen can be dissolved by the water and a more effective oxidation of pollutants such as metals or heavy metals is achieved.

[0077] In the state of the art submerged oxidation reactor described above, the spherical bubbles of gas form the contact area between oxygen and water. In the present invention however, the surface enlarger 12 causing the turbulent water surface exposed to the oxidizing agent makes up the contact surface. The movement of the water over the filler material 12 in relation to the movement of the oxidizing agent increases the uptake of oxygen by the water. The movement of the water shortens the time it takes for the oxygen to come into contact with the material to be oxidized. The water inside the oxidation reactor 10 is made up of a thin coating in movement which is continuously exposed to the oxidizing agent on one side and on the other side clinging to the filler material 12.

[0078] Fig. 2 shows a water purification system 1 comprising the water tank 10 shown in Fig. 1 A and a second water tank 30. The water purification system 1 of Fig. 2 could alternatively comprise the oxidation reactor 10 of Fig. IB. The second water tank 30 is herein also referred to as an outer water tank 30. Further, the water purification system 1 is provided with the water inlet 2 arranged in the water tank 10, and a water outlet 3 arranged in the second water tank 30.

[0079] As shown in Fig. 2, water will enter the water purification system 1 through the water inlet 2 in the water tank 10, and exit the water purification system 1 through the water outlet 3 in the outer water tank 30. An outer water tank water level WL2, also referred to as a second water tank level WL2 herein, is also indicated in Fig. 2. The water outlet 3 is arranged below the outer water tank water level WL2.

[0080] The second water tank 30 shown in Fig. 2 is an open, non-pressurised vessel. Hence, the second water tank 30 is, as opposed to the oxidation reactor 10, non-sealed. Thus, the second water tank 30 may have an open top portion (shown in Fig. 2), or be provided with apertures above the outer water tank water level WL2.

[0081] Further, the outer water tank 30 comprises an optional recirculation pump 32 being configured to pump water through a return pipe 33 from the outer water tank 30 back to the water treatment tank 10. The outer water tank 30 may also optionally comprise a further pump 34 configured to pump water from the outer water tank 30 to an external further purification media, such as a filter (for instance a bag filter, carbon filter or the like).

[0082] Fig. 2 further shows how the oxidation reactor 10 and the outer water tank 30 are arranged as communicating vessels, being in fluid communication with each other. The water treatment tank 10 in Fig. 2 is arranged partly within the outer water tank 30.

[0083] The operation of the water purification system 1 shown in Fig. 2 will now be described. Fig. 2 shows the water purification system 1 after it has been filled with water and after the oxidizing agent injector 15 has been activated. Non-purified water enters the water purification system 1 through the water inlet 2. The water thus enters the oxidation reactor 10 first. The water inlet 2 is arranged in the oxidation chamber upper portion 10a. Hence, preferably, the untreated water is supplied into the oxidation chamber upper portion 10a, above the filler material 12. In other embodiments, the water inlet 2 may be connected to another portion of the water treatment tank 10.

[0084] Preferably, the untreated water is distributed on top of the filler material 12 by the optional water distributor 13. The water then trickles downwards through the filler material 12. As described above with reference to Fig. 1 A, water droplets will adhere and flow along the surface of the filler material 12 and form a water film thereon. Therefore, a large surface area of the filler material 12 prolongs the retention time of the water in the oxidation chamber 10.

[0085] Before the oxidizing agent injector 15 is activated, and when water has been supplied to the purification system 1, the water levels WL2 and WLI will be aligned since the outer water tank 30 and the water treatment tank 10 are in fluid communication with each other. If no oxidizing agent is supplied by the oxidizing agent injector 15, and water is added to the system 1, the water levels WLI and WL2 are aligned at the same vertical height since the tanks 10, 30 are arranged as communicating vessels.

[0086] Since the oxidation chamber upper portion 10c is sealed, once the oxidizing agent injector 15 is activated, the oxidizing agent supplied will force the water level in the oxidation chamber WLI to decrease vertically, and the outer water tank water level WL2 will rise vertically. When the system 1 has reached a steady state in which the system 1 operates, the oxidation chamber water level WLI will be below the outer water tank water level WL2 as shown in Fig. 2. Hence, Fig. 2 shows the system 1 after water have been supplied to the system 1 and after the oxidizing agent injector 15 has been activated.

[0087] The water present in the treatment chamber 10 above the water level WLI will therefore be exposed to the oxidizing agent. The oxidizing agent in turn will trigger the chemical reaction of oxidation of pollutants present in the water. Hence, when the water adhered to the filler material 12 is exposed to the oxidizing agent in the water treatment tank 10, oxidation of pollutants occurs, causing the pollutants to precipitate.

[0088] The precipitated pollutants will either adhere to the filler material 12 and eventually fall off (once they aggregated precipitate on the filler material 12 becomes too heavy). The precipitated pollutants then exit the oxidation chamber 10 through the oxidation chamber outlet 17, and aggregate at the bottom of the outer water tank 30. At the bottom of the outer water tank 30 the precipitates can be drained from the water treatment system 1 through a bottom drainage 31.

[0089] Purified water may then exit the water purification system 1 through the water outlet 3. The water inlet 2 and water outlet 3 may be regulated such that the water levels WLI and WL2 are maintained at a constant level once the system 1 reach the state shown in Fig. 2. The water levels WLI and WL2 may alternatively or additionally be regulated by supplying more or less of the oxidizing agent to the water tank 10.

[0090] As described above, the filler material 12 prolongs the retention time of the water in the first water tank 10 where it is exposed to oxygen, such as ozone, O2 or air. Hence, the efficacy of the water purification is increased. It has been found that ozone is specifically efficient for purification of water containing heavy metals. Heavy metals are prone to be present in waste water stemming from for instance gas stations, different mechanical workshops, industries using hydrocarbon compounds, mechanical industries, and / or car wash facilities. The introduction of ozone further decreases drug residues and the amount of pathogens such as bacteria in the water.

[0091] Fig. 3 shows a water purification system 1 according to another embodiment of the invention. The water purification system 1 in Fig. 3 also comprises a water tank 10 of the type schematically shown in Fig. IB, and a second water tank 30 (also referred to as an outer water tank 30). The second water tank 30 of the embodiment shown in Fig. 3 is a closed vessel. The oxidation chamber 10 is arranged partly within the second water tank 30. The second water tank 30 is sealed around the water tank 10, to form the closed purification system 1 shown in Fig. 3. The second water tank 30 is thus a pressurised water tank. The oxidation chamber 10 comprises a filler material 12, being of the same type as described with reference to Figs 1 and 2.

[0092] Further, the water purification system 1 is provided with a water inlet 2 coupled to the oxidation chamber 10. Optionally, the water inlet 2 is further coupled to a water distributor 13, as shown in Fig. 3. The water distributor 13 spreads the water entering the water treatment tank 10 over the filler material 12, as indicated with the rounded arrows in Fig. 3.

[0093] The water tank 10 is also provided with an oxidizing agent injector 15, configured to supply an oxidizing agent to the water treatment tank 10. The oxidizing agent injector 15 is arranged in connection with the water inlet 2, as shown for the oxidation reactor 10 in Fig. IB. Alternatively, the oxidizing agent injector 15 could be connected directly to the oxidation reactor 10. The oxidizing agent may be oxygen supplied as a gas being air, oxygen O2, ozone O3, or a combination thereof.

[0094] Further, the water tank 10 may optionally be provided with a ventilating valve 16 as shown in Fig. 1 A, or, it may be comprise as shown in Fig. 3 at least one ventilating hole 16’ and a ventilating valve 16 in the outer water tank 30. An oxidation chamber water level WLI is also indicated in Fig. 3. The outer water tank 30 is preferably filled to the top, indicated by the dashed line WL2.

[0095] As described above, the outer water tank 30 shown in Fig. 3 is a closed vessel, having a closed top portion. This is opposed to the embodiment shown in Fig. 2, where the outer water tank 30 is non-pressurised tank, being an open tank, preferably having an open top portion (as shown in Fig. 2). The oxidation chamber 10 has a vertical extension with a top and a bottom, and comprises the features described with reference to Fig. 1 A. Hence, the oxidation chamber 10 has an oxidation chamber upper portion 10a, an oxidation chamber middle portion 10b, and an oxidation chamber lower portion 10c. The oxidation chamber middle portion 10b comprises the filler material 12. The ventilating valve 16 is either coupled to the oxidation chamber lower portion 10c as shown in Fig. 1 A, or the oxidation chamber lower portion 10c is provided with ventilating holes 16’ and the ventilating valve 16 is arranged in the outer tank 30, as shown in Fig. 3.

[0096] Further, the treatment chamber lower portion 10c is provided with a bottom opening 17. The outer water tank 30 is provided with a water outlet 3.

[0097] The water tank 10 and the outer water tank 30 in this embodiment form a hydropress, also referred to as a pressure vessel herein. Hence, the water purification system 1 shown in Fig. 3 is a closed system, where the pressure increases when the oxidizing agent is supplied to the system 1 and when additional water is supplied to the system 1.

[0098] The operation of the water purification system 1 shown in Fig. 3 will now be described. Fig. 3 shows the waste water purification system 1 in its operable state, after water has been supplied and after the oxidizing agent injector 15 has been activated to inject the oxidizing agent into the water tank 10. First, non-purified water (such as waste water or well-water) enters the water purification system 1 through the water inlet 2. The water thus enters the oxidation reactor 10 first. The water inlet 2 is arranged in the treatment chamber upper portion 10a. Hence, the untreated water is supplied into the treatment chamber upper portion 10a, above the filler material 12. The oxidizing agent injector 15 supplies the oxidizing agent to the water treatment tank 10.

[0099] Preferably, the untreated water is distributed on top of the filler material 12 by the optional water distributor 13. The water then trickles downwards through the filler material 12. This is indicated by the horizontal arrows in the oxidation chamber 10 in Fig. 3. During the flow path of the water, the water droplets will adhere to the surface of the filler material 12, and form a water film thereon as described with reference to Fig. 1 A. The filler material 12 prolongs the retention time of the water inside the water tank 10. A large surface area of the filler material 12 is therefore beneficial.

[0100] The oxidizing agent supplied by the oxidizing agent injector 15 forces the water level in the water tank WLI downwards, and thus, the water level WL2 in the outer water tank 30 upwards. Preferably, the water level WL2 in the outer water tank 30 is forced upwards until the complete outer water tank 30 is filled with water, as shown in Fig. 3. As more of the oxidizing agent is supplied to the water purification system 1 forming a pressure vessel, the pressure within the system 1 increases.

[0101] The embodiment shown in Fig. 3 has proven especially efficient for purification of water to provide drinking water. Hence, the system 1 shown in Fig. 3 efficiently reduces the amount of for instance iron (Fe) and Manganese (Mn) in the water. When the water is exposed to oxygen in the oxidation chamber 10, oxidation occurs and the pollutants in the water will precipitate. The increased pressure within the water purification system 1 shown in Fig. 3 also contributes to efficient oxidation. The oxidised, precipitated pollutants aggregate in the bottom of the outer water tank 30 and can be drained from the purification system 1 through the bottom drainage 31.

[0102] Additionally or alternatively, Iron and Manganese precipitated particles aggregate and attach to the surface of the filler material 12. When the aggregates attached to the filler material 12 becomes too heavy, they fall off and can be drained through the bottom drainage 31.

[0103] As described above, the filler material 12 prolongs the retention time of the water in the first water tank 10 where it is exposed to the oxidizing agent. Hence, the efficacy of the water purification is increased. Purified water is then allowed to exit through the water outlet 3 as indicated by the arrows in Fig. 3.

[0104] The water purification system 1 shown in Fig. 3 may also be provide with a recirculation pump 32 and / or a further pump 34 as described with reference to the water purification system 1 as shown in Fig. 2.

[0105] Fig. 4 shows a flow chart of a water purification method 100. The method 100 comprising a step of providing 110 a first water tank 10 being the oxidation reactor 10 shown in Figs. 1A or IB. Optionally, the method 100 further comprises a step providing 110B a second water tank 30 being in fluid communication with the oxidation reactor 10. Further, the method 100 comprises supplying 120 an oxidizing agent to the oxidation reactor 10 using the oxidizing agent injector 15, whereby a gaseous cushion 11 is formed above the water level WLI inside the oxidation reactor 10, and supplying 130 water through the water inlet 2 of the oxidation reactor 10. The oxidizing agent may be supplied via the water inlet 2 or directly to the oxidation reactor 10. Step 120 may further comprise regulating the pressure within the oxidation reactor 10 using a pressure regulating means, such that a pressure deviating from atmospheric pressure (i.e. a negative pressure or over pressure) is established in the oxidation chamber 10. The supply of water and oxidizing agent may take place simultaneously or one after the other, in any preferred order. Optionally, the method 100 further comprises a step of regulating 120B the oxidizing agent injector 15, and / or the water inlet 2, and / or a water outlet 3 such that the water level WLI of the oxidation reactor 10 becomes lower than a water level WL2 of the second water tank 30.

[0106] The method 100 further comprises allowing 140 the water to flow through the filler material 12 in the oxidation reactor 10, whereby the water entering the oxidation reactor 10 is brought into contact with said gaseous cushion 11 and the filler material 12.

[0107] The water tank 10 in the embodiments presented herein is an oxidation reactor 10, where oxidation of unwanted impurities present in the incoming water takes place.

[0108] The oxidizing agent injector 15 disclosed herein can be activated and deactivated, and the amount of oxidizing agent supplied can be adjusted. A preferred oxidizing agent is oxygen in gaseous form.

[0109] The water tank 1 as shown in Fig. 1 A may additionally or alternatively be provided with ventilating holes 16’ as shown in Fig. 3.

[0110] In Figures 2 and 3, the water tank 10 is arranged at least partly inside the second water tank 30. However, in other embodiments, the water tank 10 may be arranged externally of the second water tank 30 while still being in fluid communication with each other, for instance through a pipeline, channel, conduit or the like. Such embodiments are shown in Figs. 5 and 6.

[0111] Figure 5 shows an embodiment of a water purification system 1 where the oxidation reactor 10 is arranged externally of the second water tank 30. The second water tank 30 may be completely housed within the oxidation reactor 10 as shown in Fig. 5, or it may be partly arranged within the oxidation reactor 10. The oxidation reactor 10 of Fig. 5 comprises the same features and advantages as the oxidation reactor 10 shown in Fig. 1 A.

[0112] The oxidation chamber 10 in Fig. 5 is provided with a water inlet 2. The water inlet 2 has an optional water inlet valve 2’. The oxidation chamber 10 comprises the filler material 12. The filler material 12 is arranged inside the oxidation chamber 10. The filler material 12 may have various shapes and configurations, as described above with reference to Figs. 1-4.

[0113] In Fig. 5, the oxidation reactor 10 comprises an optional top opening 18 to form a non-sealed oxidation reactor 10. The top opening 18 is arranged above the oxidation chamber water level WLI. Alternatively, the oxidation reactor 10 in Fig. 5 may have a closed top, as shown in Fig. 1A. Preferably, the oxidation chamber 10 has an openable top, which can be opened to for instance exchange the filler material 12 if needed. Hence, the filler material 12 is preferably removable from the oxidation chamber 10. Additionally or alternatively, the oxidation reactor 10 has at least one opening in its upper portion 10a such that it forms an open vessel.

[0114] The water purification system 1 in Fig. 5 is further provided with a water outlet 3 arranged in the second water tank 30. As shown in Fig. 5, water will enter the water purification system 1 through the water inlet 2 in the water tank 10, and exit the water purification system 1 through the water outlet 3 in the outer water tank 30.

[0115] An oxidation chamber water level WLI is indicated in Fig. 5. The filler material 12 is entirely arranged above the oxidation chamber water level WLI . In other embodiments, the filler material 12 is arranged partly below the oxidation chamber water level WLI . Since the oxidation chamber water level WLI is below the filler material 12, the filler material 12 is surrounded by the oxidizing agent provided to the water tank 10.

[0116] Further, the second water tank 30 has an outlet 37. In Fig. 5, the outlet 37 is arranged at the bottom of the second water tank 30, but it may also be arranged in the side surfaces of the second water tank 30. The second water tank 30 in Fig. 5 is also provided with an optional ventilating valve 36. A second water tank water level WL2 is also indicated in Fig. 5. The water outlet 3 is arranged below the second water tank water level WL2.

[0117] The second water tank 30 comprises an optional recirculation pump 32 being configured to pump water through a return pipe 33 from the second water tank 30 back to the water treatment tank 10. The second water tank 30 may also optionally comprise a further pump 34 configured to pump water from the outer water tank 30 to an external further purification media, such as a filter (for instance a bag filter, carbon filter or the like).

[0118] Fig. 5 shows how the oxidation reactor 10 and the second water tank 30 are arranged as communicating vessels. The oxidation reactor 10 and the second water tank 30 are in fluid communication with each other.

[0119] The operation of the water purification system 1 shown in Fig. 5 will now be described. The method 100 described in relation to Fig. 4 is also applicable to the water purification system 1 shown in Fig. 5. Fig. 5 shows the water purification system 1 after it has been filled with water and after the oxidizing agent injector 15 has been activated. Non-purified water enters the water purification system 1 through the water inlet 2. The water thus enters the oxidation reactor 10 first. In this embodiment, the oxidation reactor 10 is the outer tank, housing the second water tank 30.

[0120] The water inlet 2 is arranged in the oxidation chamber upper portion 10a. The oxidation reactor 10 also has an oxidation chamber middle portion 10b, and an oxidation chamber lower portion 10c. Preferably, the untreated water is supplied into the oxidation chamber upper portion 10a, above the filler material 12. In other embodiments, the water inlet 2 may be connected to another portion of the water treatment tank 10.

[0121] Preferably, the untreated water is distributed on top of the filler material 12 by the optional water distributor 13. The water trickles downwards through the filler material 12. As described above with reference to Fig. 1 A, water droplets will adhere and flow along the surface of the filler material 12 and form a water film thereon. Therefore, a large surface area of the filler material 12 prolongs the retention time of the water in the oxidation chamber 10.

[0122] Before the oxidizing agent injector 15 is activated, and after water has been supplied to the purification system 1, the water levels WL2 and WLI will be aligned since the second water tank 30 and the oxidation reactor 10 are in fluid communication with each other.

[0123] When the oxidizing agent injector 15 is activated, the oxidizing agent supplied will force the water level in the oxidation chamber WLI to decrease vertically, and the second water tank water level WL2 will rise vertically. When the system 1 has reached a steady state in which the system 1 operates, the oxidation chamber water level WLI will be below the outer water tank water level WL2 as shown in Fig. 5.

[0124] The water present in the treatment chamber 10 above the water level WLI will therefore be exposed to the oxidizing agent. The oxidizing agent in turn will trigger the chemical reaction of oxidation of pollutants present in the water. Hence, when the water adhered to the filler material 12 is exposed to the oxidizing agent in the water treatment tank 10, oxidation of pollutants occurs, causing the pollutants to precipitate. The precipitated pollutants then exit the oxidation chamber 10 through a bottom drainage 31.

[0125] Purified water exits the water purification system 1 through the water outlet 3. The water inlet 2 and water outlet 3 may be regulated such that the water levels WLI and WL2 are maintained at a constant level once the system 1 reach the state shown in Fig. 5. The water levels WLI and WL2 may alternatively or additionally be regulated by supplying more or less of the oxidizing agent to the water tank 10. The water tank 10 and the outer water tank 30 in this embodiment may either form a closed system, where the pressure increases when the oxidizing agent is supplied to the system 1 and when additional water is supplied to the system 1, being a form of hydropress, also referred to as a pressure vessel herein, or the water purification system 1 is an open system as shown in Fig. 5, where the oxidation reactor 10 comprises at least one top opening 18. The top opening 18 may be provided with a valve function.

[0126] Fig. 6 shows a water purification system 1, where the oxidation reactor 10 is arranged externally of the second water tank 30. The oxidation reactor 10 and the second water tank 30 are in fluid communication with each other through a conduit 25. The conduit 25 is provided with a pump 26. The oxidation reactor 10 is provided with a water inlet 2 and an optional inlet valve 2’. The oxidation reactor 10 has an oxidation chamber water level WLI and as described for Fig. 1 A, a gaseous cushion 11 is sealed inside the oxidation chamber 10 during use. The oxidation reactor 10 further comprises the filler material 12. The oxidation reactor 10 has a valve opening 17. The second water tank 30 comprises the water outlet 3 and a valve outlet 17’. Further, the second water tank 30 has a second water tank level WL2. The conduit 25 is connected to the oxidation reactor 10 below the oxidation chamber water level WLI and is connected to the second water tank 30, preferably above the second water tank level WL2. However, the conduit 25 may be connected between the oxidation reactor 10 and the second water tank 30 at any vertical position.

[0127] Further, the second water tank 30 in Fig. 6 is provided with an optional partition wall 35. The partition wall 35 is arranged vertically, and may force the water entering the second water tank 30 to flow downwardly and around the partition wall (as indicated by the arrows in the second water tank 30).

[0128] In all embodiments herein, the oxidation reactor 10 may either be a closed reactor comprising the water inlet 2 and an optional ventilating valve 16, or the oxidation reactor 10 may be an open reactor (as shown in Fig. 5) comprising the water inlet 2 and a top opening 18, and an optional ventilating valve 16.

[0129] The water tanks 10, 30 are preferably made form a metal, such as stainless steel.

[0130] In all embodiments herein, the oxidation reactor 10 and / or the second water tank 30 may have a conically shaped or rounded bottom. This will facilitate aggregation of precipitated pollutants.

[0131] The ventilating valve 16, 36 which may be present in the embodiments disclosed herein may be used to remove an excess of air or oxygen present in the water purification systems 1. The ventilating valve 16 is either present as a conduit connected directly to the water treatment chamber 10 as shown in Fig. 1 A, or as a ventilating valve 16 connected to the second water tank 30. If the ventilating valve 16 is connected to the second water tank 30, ventilating holes 16’ are preferably arranged in the water treatment chamber 10. One or more ventilating valves 16 may be present in the systems 1 disclosed herein.

[0132] In other embodiments not shown herein, the water inlet 2 may be connected to another portion of the water treatment tank 10 or the second water tank 30. However, it is preferred that the untreated water is then further diverted to be supplied or sprinkled above the filler material 12, to increase the retention time of the water in the treatment chamber 10 and the contact surface between the water and the oxidizing agent as much as possible to achieve effective oxidation.

[0133] The water purification systems 1 disclosed herein may be used to treat and purify water comprising impurities such as iron, manganese, pharmaceutical residues, PF AS, pathogens, and / or heavy metals. The water purification systems 1 according to the present invention are therefore suitable for purification of waste water stemming from for instance industries releasing water comprising heavy metals, water works for instance configured to purify sea or lake water, or well-water to be rinsed from impurities to become readily drinkable by humans.

[0134] The oxidation capacity of the water purification system 1 depend on both the size of the water droplets sprinkled into the water oxidation chamber 10, and the contact time (i.e. the retention time in the oxidation chamber 10) between the water and the oxidizing agent available in the air cushion 11 formed in the oxidation chamber 10.

[0135] The invention presented herein surprisingly drastically increases oxygenation and oxidation capacity, by multiplying not only the contact surface area between the water droplets and the filler material 12, but also the contact time between water and the oxidizing agent. The oxidation capacity of the oxidation chamber 10 is further enhanced when ozone is supplied, which has proven especially effective for oxidizing and precipitating heavy metals, reducing drug residues and bacteria. The oxidation reactor 10 presented herein has a wide range of applications for the purification of both drinking water and waste water. The invention largely eliminates the need for different types of filter media to oxidize iron and manganese in drinking water.

[0136] In Fig. 7, an enlarged with of the filler material 12 of the oxidation reactor 10 is shown. Water flows in the direction of the bold arrows shown in Fig. 7. With the aid of gravity, the water flows downwardly, and clings onto the surface area of the filler material 12. The water forms a water film 5 on the outer surface of the filler material 12. The oxidizing agent 6 is supplied to the oxidation reactor 10. The oxidizing agent 6 moves turbulently in the gaseous cushion 11, as indicated with the arrows connected to each oxidizing agent 6. The oxidizing agents 6 are brought into contact with contaminating particles present in the water film 5 and oxidation takes place, resulting in products from the oxidation process 7.

[0137] The drawings presented herein are schematical drawings and not in scale.

[0138] The invention has been described above in detail with reference to embodiments thereof. However, as is readily understood by those skilled in the art, other embodiments are equally possible within the scope of the present invention, as defined by the appended claims.

Claims

CLAIMS1. An oxidation reactor for water purification, wherein the oxidation reactor(10) comprises a water inlet (2), an oxidizing agent injector (15) configured to supply an oxidizing agent to the oxidation reactor (10), and a filler material (12) arranged inside the oxidation reactor (10), wherein the filler material (12) is arranged above a water level (WLI) inside the oxidation reactor (10), whereby a gaseous cushion (11) of the oxidizing agent is formed above the water level (WLI) inside the oxidation reactor (10), and whereby water entering the oxidation reactor (10) is brought into contact with said gaseous cushion(11) and the filler material (12).

2. The oxidation reactor according to claim 1, wherein the water inlet (2) is arranged above the filler material (12).

3. The oxidation reactor according to claim 1 or 2, wherein the oxidation reactor (10) is sealed, whereby the oxidation reactor (10) operates at an overpressure.

4. The oxidation reactor according claim 3, wherein the oxidation reactor (10) comprises an outlet (17) arranged below the water level (WLI) inside the oxidation reactor (10), whereby the water level (WLI) prevents oxygen in the gaseous cushion (11) from exiting from the oxidation reactor (10).

5. The oxidation reactor according to any one of claims 1 to 4, wherein the oxidizing agent injector (15) is arranged in connection with the water inlet (2) or is connected directly to the oxidation reactor (10).

6. The oxidation reactor according to any one of claims 1 to 5, wherein the filler material (12) is made from irregularly entangled filaments.

7. The oxidation reactor according to any one of claims 1 to 6, wherein the filler material (12) is made from a material having a rugged surface.

8. The oxidation reactor according to any one of claims 1 to 7, wherein the oxidizing agent injector (15) is configured to supply oxygen as a gas being air, oxygen O2, ozone O3, or a combination thereof.

9. The oxidation reactor according to any one of claims 1 to 8, wherein the oxidation rector (10) further comprises pressure regulating means.

10. A water purification system, wherein the water purification system (1) comprises:- a first water tank (10) in the form of an oxidation reactor (10) according to any one of claims 1 to 9;- a second water tank (30) being in fluid communication with the first water tank (10).

11. The water purification system according to claim 10, wherein the first water tank (10) is at least partly arranged inside the second water tank (30) and at least partly below a water level (WL2) of the second water tank (30).

12. The water purification system according to claim 10, wherein the second water tank (30) is at least partly arranged inside the first water tank (10) and at least partly below a water level (WLI) of the first water tank (10).

13. The water purification system according to claim 10, wherein the first water tank (10) is connected to the second water tank (30) through a conduit (25).

14. The water purification system according to any one of claims 10 to 13, wherein the second water tank (30) comprises a water outlet (3).

15. The water purification system according to any one of claims 10 to 14, wherein the water level (WLI) of the first water tank (10) is lower than a water level (WL2) of the second water tank (30).

16. The water purification system according to claim 11, wherein the first water tank (10) and the second water tank (30) forms a sealed system, wherein the second water tank (30) is sealed around the first water tank (10), and in which the firstwater tank (10) and the second water tank (30) are in fluid communication with each other; or wherein the first water tank (10) and the second water tank (30) forms a nonsealed system, wherein the second water tank (30) comprises an open top portion or is provided with at least one aperture above a second water tank water level (WL2), and in which the first water tank (10) and the second water tank (30) are in fluid communication with each other.

17. The water purification system according to claim 12, wherein the first water tank (10) and the second water tank (30) forms a sealed system, wherein the first water tank (10) is sealed around the second water tank (30), and in which the first water tank (10) and the second water tank (30) are in fluid communication with each other; or wherein the first water tank (10) and the second water tank (30) forms a nonsealed system, wherein the first water tank (10) comprises at least one top opening (18), and in which the first water tank (10) and the second water tank (30) are in fluid communication with each other.

18. A water purification method, said method (100) comprising the steps of: providing (110) a first water tank (10) being an oxidation reactor (10) according to any one of claim 1 to 9; supplying (120) an oxidizing agent to the oxidation reactor (10) using the oxidizing agent injector (15), whereby a gaseous cushion (11) is formed above the water level (WLI) inside the oxidation reactor (10); supplying (130) water through the water inlet (2) of the oxidation reactor (io); allowing (140) the water to flow through the filler material (12) in the oxidation reactor (10), whereby the water entering the oxidation reactor (10) is brought into contact with said gaseous cushion (11) and the filler material (12).

19. The water purification method according to claim 18, wherein the method comprises a step providing (HOB) a second water tank (30) being in fluid communication with the oxidation reactor (10).

20. The water purification method according to claim 18 or 19, wherein during the supplying step (120) the oxidizing agent is supplied either in connection with the water inlet (2) or directly to the oxidation reactor (10).

21. The water purification method according to any one of claims 18 to 20, further comprising a step of regulating (120B) the oxidizing agent injector (15), the water inlet (2) and a water outlet (3) such that a water level (WLI) of the oxidation reactor (10) becomes lower than a water level (WL2) of the second water tank (30), or such that a predetermined pressure is reached in the oxidation reactor (10).

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