MX2008008649A - Bioreactor and method for the biological purification of water - Google Patents

Abstract

The invention relates to a bioreactor (1) for the purification of waters, said reactor comprising a cross-sectionally essentially circular or elliptical tank section (2) provided with inlet means (5) for water to be purified and outlet means (6) for purified water. The tank holds thereinside carrier material (3) on which a biofilm may develop. The tank is further provided with means (4) for supplying a fluid which contains a reaction gas required by the purification process, such that the water to be purified develops gas bubbles containing a reaction gas. The tank section is adapted to be essentially full of water during the purification process. The fluid supply means (4) are disposed on the tank wall and the reactor comprises control means for operating the fluid supply means in such a way that a spinning motion of the carrier, the water, and at least some of said reaction-gas bearing bubbles is effected thereby around a rotation centerline passing essentially through the tank's cross-sectional center. The control means are adapted tooptionally effect a deactivation of the fluid supply means at desired times and/or a replacement of the fluid with an oxygen-free fluid for providing an anaerobic process. The invention relates also to a method for the biological purification of waters in a bioreactor.

Description

BIOREACTOR AND METHOD FOR THE BIOLOGICAL WATER PURIFICATION FIELD OF THE INVENTION The present invention relates to a bioreactor for the purification of water, said reactor comprises an essentially circular or elliptical transverse tank section provided with medium :; inlet to purify water and outlet means for the purified water, said tank holds carrier material therein in which a biofilm can be developed, and said tank is further provided with the means to supply the air required for a aerobic purification process.

The invention also relates to a method for the biological purification of water in a bioreactor, which comprises an essentially circular or elliptical transverse tank section that is provided with inlet means for purifying water and exit media for purified water , said tar, which holds within the same carrier material in e. '. which a biofilm can be developed, and said in addition is provided with the means to provide the air required by an aerobic purification process.

BACKGROUND OF THE INVENTION Biological purification of water, such as, for example, wastewater, passes through a reactor, where micro-organisms are used to convert impurities suspended in the water into harmless end products such as carbon dioxide, minerals and Water. In the biological purification of water, the microorganisms can agglomerate with each other, that is, with the biomass, also products that are not biodegradable, for example, heavy metals. The purification can be carried out aerobically or anaerobically. Several bioreactors are previously known for the purification of waste water, such as sewer trickling filters, biorotors (with: biological rotation acts) fluidized bed reactors, fixed bed reactors, and mobile bed reactors. A bioreactor known above comprises transporting a carrier material by a process, the surface of said carrier material having the ability to grow microorganisms in the form of a biofilm.

A typical biofilm process (fixed bed reactor) is based on filling the purification reactor with a carrier material in the form of filler particles, said filler particles being adapted to remain stationary during the process. Oxygenation of a biofilm present on the surface of the filler particles is affected by providing the reactor with air through the bottom. One advantage of the process is a large amount of biomass per unit volume of the reactor when the biofilm has: a large growth area. A disadvantage in this type of so-called fixed bed is that bioprocesses can be brought to a standstill by biomass (sludge) or other particles in suspension, and that inactive zones can develop in the process in places with poor contact between water and active microorganisms. Another problem is the difficult cleaning due to difficult access under a reactor and, if a bioreactor is obstructed, the total volume of the bioreactor must be emptied for cleaning.

Also known are biofilm processes, where the carrier material is kept in motion during the process, see, for example, US Patents. No. 6,126,829, E.U.A. No. 5,458,779, and E.U.A. No. 5, 543, 039. An advantage in such a mobile bed type bioreactor is that the obstruction of a carrier material and the development of inactive zones are substantially eliminated. The surface of carrier elements is partially protected against collisions with other carrier elements. A disadvantage here is, however, a considerably limited capacity of the process attributable to the fact that a particularly low degree of filling is required, for example, in an order of about 30-70% of an empty reactor volume, to supply the carrier elements with free mobility in the water that will be purified. Therefore, the ability to remove impurities is lower than that of a fixed bed reactor which has the same volume and is filled with the same carrier material, because the fixed bed reactor has a capacity of higher load.

SUMMARY OF THE INVENTION Increasing the degree of filling could result in increased oxygen consumption, which requires a more powerful compressor, so the strong explosion can also destabilize:.: Bioprocesses. Increasing the degree of filling could result in the formation of a fixed bed and could lead: the biological process to a standstill when the carriers can be stuck by the biomass. In addition to this, if the degree of filling in a mobile bed of the reactor type that will be increased, may require an adverisadamente large amount of air and energy to keep the carriers in motion, which in turn could markedly increase the applied mechanical pressure to a biofilm and this, in turn, would result in the desquamation of the bicpelicula of the carrier surface, which in turn results in a paralysis of the biological process. Another very important disadvantage is that the reactor must be provided with a safety screen to separate the aeration means from the carrier elements. The screen must have a mesh size such as to prevent the passage of carrier elements through the openings. This prevents the use of small size carriers which could provide a large area per unit volume, because a corresponding reduction in mesh size of the screen can impair the air supply and is likely to cause blockage of the openings .

An object of the present invention is to provide an improved bioreactor that has the ability to eliminate the disadvantages of both a fixed bed process as well as a moving bed process, resulting in a higher rate of treatment of impurities per unit than that achieved by the previously known reactors, and thus reducing purification costs. In order to achieve this objective, a bioreactor of the present invention is characterized in that the tank section is essentially circular or elliptical in cross section, so that water outlet means are provided in the tank section such that the tank section is essentially full of water during the purification process, because the fluid supply means are placed in the wall of the tank, and because the reactor comprises control means for operating the fluid supply means in such a way as to rotate the carrier, the water, and therefore the reaction of fluid carrying gas about a rotation of the central line passing essentially through the transverse center of the tank is affected, the control means are adapted to optionally cause a deactivation of the means for supplying fluids at desired times.

An idea in accordance with the present invention, the tank section is kept essentially full of water during the purification process, allows a reaction gas, for example, in the form of gas bubbles, traveling at the same time as water and a carrier, giving of this node, a distance and time of great effectiveness to the bubble, to allow therefore a high degree of filling for the carrier, preferably within the range of more than 70% to approximately 100%, in deference to the previously known mobile bed type of solution which explains that the filling degree of a carrier material is within the range of 30-70%. The degree of filling of a carrier material is in direct proportion to the performance of a biological process, ie, the more high is the degree of filling of a carrier material in an mVm3 reactor, the higher is its purification performance. In a solution according to the present invention, the amount of a carrier material can also differently less than 70%, for example, less than 50%. The degree of filling for a carrier material is determined based on the capacity and oxygenation load of a reactor. The carriers may consist of plastic pieces of a desired size and shape to allow movement of sustained g. When a reactor of the present invention is used, it has been discovered that in an aerobic process, the air bubbles remain in the reactor for a considerably longer time than in the reactors currently used, since the air bubbles rotate for quite some time together with the carrier material and the water for a more efficient oxygenation of the biofilm. Simultaneously, the air bubbles break into smaller ones, which is another factor that contributes to the transfer of oxygen from the air into the water. This reduces the amount of air and consequently reduces operating costs compared to the type of activated sediment process, fixed bed, and type of mobile bed.

On the other hand, a method of the present invention characterized in that, in a bioreactor used in the method, the tank section is essentially circular or elliptical in transverse and the fluid supply means are placed in the wall of the tank, because the method comprises providing the tank with unpurified water in such a way that < 1 tank is essentially filled with water during the purification process, and because the fluid supply means are controlled in such a way that a rotational movement of the carrier, the water, and the fluid reaction that transports gas through therefore, continuously or intermittently about a turn of the central line cue passes essentially through the transverse center of the tank.

A solution of the present invention allows a large biofilm growth area and the reactor does not develop dead zones with the carrier, water, and fluid reaction that transports gas that rotates at an approximately consistent angular velocity around a central line of rotation in only one section. The various sections in a bio:. Reactor, however, can be moved in different directions.

One type of rotating actor biorr of the present invention, in which the carrier elements are rotating in the same direction, is clearly distinguished from a prior art moving bed type process, in which the carrier elements move in chaotic order in the water, which allows only the use of a relatively low degree of filling. If the degree of filling exceeds 70%, the type of moving bed of the process can be converted into a type of fixed bed when the particles are in chaotic motion collide with each other, at a higher frequency and leading to movement of the same to a standstill and results in the binding of a bioreactor. It is a particularly advantageous feature, in accordance with the invention, that the tank section is adapted to be filled with water during the operation, by which the energy needed to rotate a carrier material is at its minimum and in it the bubbles of gas rotate, in the same way as the carrier material, at the same time as the water around a rotation of the central line, whereby the distance and effective time thereof become multiple, when comparing, for example, with ana mobile bed solution of the previously known type, which involves the use of a liquid level and in which the air bubbles only pass essentially from the point of air intake, which is typically at the bottom of a tank , up to an air space present in the upper part of the tank. In this description, the term "essentially full of water" is used, in reference to the tank that It contains so much water that the supply of a fluid has the ability to configure the carrier, the water, and the fluid reaction that transports gas or in a rotary motion around a central line rotation that passes essentially through the center transverse of the tank. It has been found experimentally that the amount of water must be more than at least about 85%, preferably about 100%, of the cross-sectional diameter. In case the amount of the water is less than about 85%, the process becomes a type of mobile bed process, in which "the degree of filling of a carrier material must be less than 70% for the process Work instead of becoming a fixed bed type. Another reason why the type of mobile bed of the solution uses a relatively low degree of filling and the carrier elements, are made to the shape in a specific way is to protect the biofilm from the damage caused by the carrier elements that they collide repeatedly. The solution according to the present invention preferably utilizes a semifixed bed solution, in which the carrier material consists of a plurality of carrier elements having a filling degree in the tank section of approximately 100% and, for consequently, they do not essentially move with respect to each other as they revolve around a line central in the center but, instead of, rotate in the form of an essentially integral carrier bed. Therefore, the composition of carrier elements is not as critical as in a mobile bed type solution, in which the movement of carrier elements relative to one another must be taken into consideration. One solution of the present invention allows to use a more delicate fluid explosion, which does not affect the bacteria on the surface of a carrier material since, by virtue of the optimum rotary motion, the method of the present invention does not require a large amount of fluid for the sustained movement of the carrier. What is essential from the point of view of biology is that the biofilm does not become mechanically poured out of the carrier surface by gas bubbles. Because the supply of fluid is located in the outer periphery and carriers do not move in relation to each other, neither is there any mechanical stress, largely due to the high degree of filling of more than 70% . On the other hand, dead bismuth or excessive mud is forced out of the bioreactor by the law of inertia. If, in a revolving movement, a biomass begins to accumulate towards the origin, it is where the density also begins to increase, which, in turn, is a consequence of the carriers present in the environment starting a gradual migration towards the outer periphery and the biomass that is in the outer periphery that has the ability to emerge out of the bioreactor in response to the law of inertia.

The degree of filling of a carrier material is a term used in reference to the amount of space required by a carrier material with respect to the volume of tank section in its empty condition, but not in reference to the volume of water displaced. When a plurality of carrier elements is used, the 100% degree of filling is indicative of the fact that no more carrier elements can fit in the volume of a tank section.

BRIEF DESCRIPTION OF THE FIGURES The invention will now be described in more detail with reference to the accompanying figures, in which: Figure 1 shows a bioreactor in accordance with the present invention in a schematic side view, and Figure 2 shows the reactor of Figure 1 in an end view.

Figure 3 shows a carrier element of the present invention in a schematic view of the principle.

Figure 4 shows an alternative form for a carrier element.

DETAILED DESCRIPTION OF THE INVENTION As shown in the figures, a bioreactor 1 of the present invention comprises a tubular tank portion 2, which is preferably circular or elliptical in cross section. The tank portion 2 is provided with inlet means 5 for purifying the water and outlet means 6 for the purified water, as well as with means 4 for providing a fluid containing a reaction gas required by the purification process , preferably of a barrier such that the water to be purified develops the gas reaction that transports gas bubbles, such as to provide air, in the form of air bubbles, required for example, by an aerobic purification process, from which the air dissolves in the water to oxidize it for bacterial activity. The fluid may also consist of pre-aerated water with air present in the form of air bubbles and / or in a previously dissolved form to provide water rich in oxygen. In the illustrated case, described only by way of example, the inlet means 5 and outlet means 6 for water to be placed at the longitudinally opposite ends of a tank portion 2 in the upper portion of the tank section. The input and / or output means can also be located elsewhere in the tank portion 2, in an arrangement so that the supply of unpurified water and the discharge of purified water can be performed in such a way that the portion tank 2 is essentially filled with water during the purification process. In the figures, the water level is designated with a reference character W. The supply of water that will be purified preferably proceeds in continuous action, for example, having an upward flow of the reservoir that gives a balance of the bioreactor to collect the water that will be purified and pumped from there in a continuous feeding by means of a tube 5 to the bioreactor. The water supply that: >The purified section can also proceed in a batch process, whereby the tank section is supplied with the water that will be purified to its capacity, an air explosion is started for the rotation movement and oxygenation and, a Once the purification process ends, the explosion is interrupted of air and the tank section of the purified water is emptied, followed by the restart of the process.

A carrier material 3 is provided within the tank section, in which microorganisms can be deposited as a biofilm. The carrier material may be, for example, a carrier element alone or in a plurality of firmly connected carrier elements or a plurality of discontinuous carrier elements, whereby, in the latter case, the carrier elements may be identical or different from each other, for example, in relation to the size, shape, density and / or other properties thereof.

In the exemplary case of figure 1, a tank with a plurality of discontinuous carrier elements 3 has been loaded to almost 100% filling degree, such that said particles have the ability to make a turn around the longitudinal center line of the tank by virtue of the circular or elliptical cross-section of the tank element as an essentially integral carrier bed in a given direction of rotation. The internal surface of a tank section 2 is essentially smooth for the unimpeded rotation of the carrier, the air supply means being placed on the external surface of the tank element 2. In the illustrated mode, the air supply means 4 are placed in the supply passages 8, which are arranged inside a protective cap 7 that surrounds the tank at least partially and that is each connected by means of an e. Valve element (not shown) to an inlet air source. Each passage 8 preferably includes several air supply means or nozzles 4 in succession along the tank, but can also be provided with a single integral nozzle element covering the tank essentially over its entire length. Each nozzle element 4 can be provided with an aeration element, for example, a membrane, which during a normal air supply flow allows the flow of air into the tank while preventing the admission of purified water present in the tank. tank inside the passage 8. The membrane is useful to get a smaller size of the air bubble, and the smaller the size of an air bubble, the lower its buoyancy, and therefore the smaller air bubble rotates effortlessly around a bioreactor co-directionally with the carriers. The aeration element may also comprise, for example, an open tube or ventilation hole in the walls of a bioreactor. In front of the air nozzles you can place a safety screen, which prevents the Air bubbles collide with the carrier material in a way that damages the biopicula. In connection with the outlet tube 6, a ventilation tube (not shown) is preferably placed to remove excess air from the tank. The upper side of the tank section 2 can be provided with tiny ventilation holes (not shown), whose function is to avoid the development of possible air pockets in the upper part of a tank, which can decrease the turning speed of water in the tank, thus increasing the energy consumption. Such ventilation holes are preferably connected to a ventilation pipe (not shown) placed for example, together: > with the outlet tube 6. The tank 2 is preferably placed in a horizontal position and the passages 8 are placed in and / or below a longitudinal median plane d = l tank 2. In the case of a tank which for example, is essentially circular in cross-section, the nozzle elements 4 can be placed for example, in one or more positions that coincide with the clock positions at 3, 4, 5, 6, 7, 8 and 9 in a normal clock face . In association with the reactor, logic control is also provided, whereby the multi-passage supply valve can optionally be changed and therefore, for example closing the passages 8 with nozzle elements placed in the ports. positions from 6 to 9 o'clock in the watch, the air proceeding through the nozzle elements present in the 3 o'clock to 5 o'clock positions, causes approximately a rotation of the carrier material in the tank around the central longitudinal line of the tank. Such an intermittent rotation pulse of the carrier material may be, for example, about 1 minute for every other hour. Naturally, the cyclicity can even be drastically different from the other, both in terms of duration of spinning time and repetition of frequency. In addition, the cycle can be irregular. Another way of instrumentalizing a bioreactor of the present invention by adapting the supply of air to rotating impulse carrier elements during the continuous purification process in action around a longitudinal centerline for an efficient dynamic consistent movement to remove sludge from the reactor . In this case, the tank 2 is only provided with one aeration element, preferably for example, in a position of 3 or 9 o'clock in the watch, the aeration element can be for example, a single passage of air supply 8 provided with its nozzle elements and extends along the tank 2, whose nozzle elements may be, for example, in the form of aeration holes made in the wall of the tank 2 in coincidence with the passage. When the The fluid employed comprises a gas-containing liquid reaction, in which the reaction gas is in an already dissolved state and essentially does not contain gas bubbles from which the reaction gas must first be dissolved in water, for example, the air containing dissolved water, the fluid supply can be instrumented basically from any place along the periphery of the tank, for example, from a position approaching 12 o'clock in a clock.

One of the benefits provided by a solution of the present invention is, for example, to avoid the deceleration inflicted by turbulence of a biological microprocess, which is what occurs in a process with carrier elements that move constantly in random directions. In addition, the degree of filling can be made essentially higher than in a type of mobile bed of the process. When s < i compares with a fixed bed process, in which the carrier remains essentially stationary throughout the process, a solution of the present invention is that. it has the capacity to use carriers of smaller size whose surface area per cubic unit of a bioreactor is larger, which results in an increased cleaning capacity. In a fixed bed process, the carrier element size must be relatively large for the binding of the same inflicted by mud. By virtue of the regular rotational movement of a carrier material according to the invention, caused by intermittent or continuous action, there is no accumulation of sludge in comparison with a fixed bed process.

Another mode of operation for a bioreactor of the present invention is such that the air supply is completely interrupted periodically to convert the aerobic to anaerobic process to allow the use of one and the same volume of bioreactor for denitrification in which the Nitrogen, present as a nitrate, is reduced to nitrogen gas (N03? N02 - »NO? N20? N2).

A bioreactor of the present invention can be used, for example, as part of a purification system for waste water black and / or gray from a single house, such that the bioreactor is preceded by a septic section and a section of anaerobic, followed by carrying the water that will be purified inside the bioreactor for aerobic treatment. The bioreactor is still preferably followed by a second aerobic bioreactor that has the ability to perform nitrification (NH3? N02? N03), after which the water is sent to a denitrification process. Definitely, The purified water is sent to a phosphorus precipitation section and to a secondary settlement tank. Naturally, a bioreactor of the present invention is in fact useful in a wide range of applications, such as sewage works, car wash facilities, laundries, schools of fish, and in the purification, for example, of water cleaning. swimming pools, sanitary landfill filtration water, mine water, industrial scrubbing and foaming, and waste water discarding brushes to clean gas or similar chimneys, and there may be several bioreactors in succession and / or on one side other.

A bioreactor of the present invention can also be instrumented in a manner such that the tank section is divided into two or more sections, whereby some of the sections can work aerobically, that is, have an air supply adapted for configure a carrier, air bubbles and water in spinning motion during the purification process in continuous action, and the other sections can work anaerobically. In an anaerobic process, the supply of a fluid that allows rotation is intermittently or optionally the carrier material an assembly in a continuous or cyclic rotating motion upon re-circulating water or other fluid, which does not contain dissolved oxygen and / or gas bubbles that transport oxygen in the amount required by an aerobic process, through the openings present in the reactor wall.

The movement of the iris can also be caused by a fluid other than air, for example, by water, which is pre-aerated before being sent into a tank section that contains the water that will be purified and whose water is sent in such a way that air carried within it causes bubbles in the tank section that contains the water that will be purified. The pre-aerated water can also contain its air in an essentially dissolved state and in that case the transport of dissolved air, the oxygen-rich water can function in an aerobic process even without a large bubble formation. The purification process can also be a process that requires a gas other than oxygen, and in which case the fluid that will be supplied can be a gas or gas mixture other than air or it can also be water or another liquid that contains the gas of reaction.

A solution of the present invention can be instrumented not only by means of a tubular elongated tank section but also a tank section which is essentially spherical, wherein The carrier rotates symmetrically in a direction around a central line of rotation that passes through the center of the sphere. As described above, the carrier material may consist for example of a single carrier element or a plurality of firmly attached carrier elements or a plurality of discontinuous carrier elements, whereby, when a plurality of carrier elements are used, the carrier, the latter can be identical or different from each other, for example, in terms of size, shape, density and / or other properties thereof. Therefore, in the vertical transverse direction, the air supply means are placed between 3 and 9 o'clock, so that the created turning motion thus preferably proceeds around a central line of essentially horizontal rotation. The tank section is also conceived as a structure having a shape of an ellipsoid or an ellipsoid generated by the rotation or for example, as a plate or disk as a small tube with essentially a circular cross section and a length which is in the same range or smaller than the transverse diameter.

The carrier material useful in a bioreactor of the present invention can consist of an ion exchanger or contains an ion exchanger, for example, a ceramic material. the use of a Ion exchanger improves denitrogenation, nitrogen uptake by the ion exchanger and eating of the bacteria. Preferably, the carrier material comprises a polymeric ceramic composite, for example, a polymeric zeolite compound.

The amount of water in a tank of approximately 100%, for example, by placing the water inlet and outlet pipes such that the surface of the water rests above the tank, prevents the carrier elements heavier than the tank. water leave the body of the water without other measures, even if the carrier elements are provided in an extraordinarily small size.

The carrier element is preferably spherical in shape to achieve optimum rotation of the carrier material in a tank section, and an optimum filling degree is also obtained. The spherical carrier element may be for example, as described in British Patent 2197308, wherein the water to be purified may flow through a carrier element, or for example, a solid sphere element, having its surface provided with hemispheric depressions in which a biofilm can be developed safely so that it is contacted by the adjacent carrier elements.

An alternative form for a carrier element is a disc-like element 30 shown in FIGS. 3 and 4, it comprises a middle section 32, which is reduced in thickness compared to an edge section 31 and which is formed with pyramidal protrusions 33 that achieve a multiplication of a biofilm growth area as compared to a soft particle and at the same time protect the biofilm as collisions occur with the adjacent carrier elements. The middle section can also be provided with through holes. The disc 30 may have a diameter of, for example, approximately 5 mm, and its thickness in the edge section 31 may be, for example, approximately 1 mm while its density is approximately 1.1 kg / m 3. These values are taken of course only as suggested non-restrictive examples and the shape, size and density of the carrier elements can be significantly deviated from the previous ones. This type of carrier element is also conceived for use for example, in a type of mobile bed bioreactor.

Claims (19)

NOVELTY DH THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as a priority: CLAIMS

1. - A bioreactor (1) for water purification, said reactor comprises a tank section (2) which is provided with inlet means (5) for the water to be purified and outlet means (6) for the purified water, said tank maintains within it a carrier material (3) in which a biofilm can be developed, and said tank is further provided with means (4) to supply a fluid which contains a reaction gas required by the process of purification, characterized in that the tank section is essentially circular or elliptical in cross section, because the water outlet means (6) are provided in the tank section (2) such that the tank section (2) is essentially full of water during the purification process, because the fluid supply means (4) are placed in the wall of the tank, and because the reactor comprises control means for operating the fluid supply means in such a way that a movement is made of carrier rotation, water, and reaction of fluid that transports gas therethrough about a central line of rotation that passes essentially through the transverse center of the tank.

2. - The bioreactor according to claim 1, characterized in that the carrier material (3) consists of one or more carrier elements, and because the carrier material (3) has a filling degree in the tank within the range of more from 70% to approximately 100%.

3. - The bioreactor according to claim 1, characterized in that the carrier material consists of a plurality of carrier elements that have a filling graph in the tank section of approximately L00%, thus rotating in The shape of a carrier bed essentially continuous around the centimeter line of rotation once the tank section is supplied with said fluid.

4. - The bioreactor according to any of the preceding claims, characterized in that the tank section has its internal surface made essentially smooth, allowing unimpeded rotation of the carrier material around the longitudinal center line.

5. - The bioreactor c according to any of claims 1-4, characterized in that the purification process is adapted to proceed as an aerobic process, and because said fluid reaction transporting gas comprises air, which is provided inside the tank that it contains water that will be purified in a way to produce bubbles from which air dissolves in water.

6. - The bioreactor according to claim 5, characterized in that a protective cover (7) is provided around the tank section (2), housing the tank section at least partially and characterizing at least one air supply passage ( 8), which is connected by means of valve means to an air supply source and whose passage (8) is adjusted with air supply means (4).

7. - The bioreactor according to claim 6, characterized in that the air supply means (4) present in the passage (8) comprises a plurality of nozzle elements arranged successively in the longitudinal direction of the passage.

8. - The bioreactor according to claim 7, characterized in that each nozzle element is provided with a membrane, which allows a flow of air supply inside the tank while essentially blocking the admission of unpurified water into the tank within the passage (8;

9. - The bioreactor according to claim 6, characterized in that the air supply means consist of aeration openings made in the wall of the tank (2) aligned with at least one passage (8).

10. - The bioreactor according to any of claims 1-4, characterized in that the purification process is adapted to proceed as an anaerobic process, so that the control means are adapted to optionally perform a deactivation of the supply means of < : fluid at desired times and / or a replacement of the fluid with an essentially free reaction gas.

11. - The bioreactor according to any of the preceding claims, characterized in that the control of the fluid supply means are instrumented as a logic control.

12. - The bioreactor according to any of the preceding claims, characterized in that the tank section (2) is a tubular or elongate disc structure placed in an essentially horizontal position.

13. - The bioreactor according to any of claims! .- 10, characterized in that the tank section (2) has a structure that is essentially spherical or ellipsoid that is generated by the rotation.

14. - A method for the biological purification of water in a bioreactor, comprising a tank section (2) which is provided with inlet means (5) for the water to be purified and outlet means (6) for the purified water said tar, which holds within the same carrier material (3) in which a biofilm can be developed, and said tank is further provided with means (4) to supply a fluid which contains a reaction gas required by the process of purification, characterized in that, in a bioreactor used in the method, the tank section (2) is essentially circular or elliptical in cross section and the fluid supply means (4) are placed in the wall of the tank, because the method comprises supplying the tank with water that will be purified so that the tank is essentially filled with water during the purification process, and because the fluid supply means are controlled in such a way that a movement is made the rotation of the carrier, the water, and the reaction of the gas that transports fluid, therefore, continuously or intermittently around a central line of rotation that passes essentially through the transverse center of the t.anque.

15. - The method according to claim 14, characterized in that the method comprises the use of carrier material consisting of one or more carriers, and in that the carrier material (3) has a degree of filling in the tank within the range of more than 70% to approximately 100%.

16. - The method according to claim 14 or 15, characterized in that the purification process is adapted to proceed as an aerobic process and because the air is used as said fluid reaction that transports gas, which produces bubbles in the water that will be purified, at least some of the air bubbles that rotate, together with the carrier material and water, around said central line of rotation.

17. - The method according to claim 14 or 15, characterized in that the bioprocesses are adapted to proceed as an aerobic process and because the p:.: E-aerated water is used as said gas reaction that transports fluid, in which the air has dissolved and / or is present in the form of bubbles.

18. - A method according to claim 14 or 15, characterized in that the bioprocesses are adapted to optionally proceed as an anaerobic process by deactivating the fluid supply at desired times and / or by replacing the fluid with an essentially free reaction gas.

19. - A carrier element for a biological process, characterized in that the carrier element is formed as a disk or plate, which includes an edge section (31) of increased thickness and a middle section (32) of reduced thickness, said middle section it is formed with conical or pyramidal protrusions (33) to increase the growth area of the b: .. opelicula. SUMMARY OF THE INVENTION The present invention relates to a bioreactor (1) for the purification of water, said reactor comprises an essentially circular or elliptical transverse tank section (2) provided with input means (5) for the water to be purified and exit means (6) for purified water. The tank holds within the same carrier material (3) in which a biofilm can be developed. The tank is further provided with means (4) for supplying a fluid containing a reaction gas required by the purification process, so that the water to be purified develops gas bubbles containing a reaction gas. The tank section is adapted to be essentially filled with water during the purification process. The fluid supply means (4) is placed in the tank wall and the reactor comprises control means for operating the fluid supply means so that a rotating movement of the carrier, the water is therefore carried out. , and at least some of said gas reaction conveying bubbles, around a central line of rotation that passes essentially through the transverse center of the tank. The control means are adapted to optionally perform a deactivation of the fluid supply means at desired times and / or a replacement of the fluid with a free fluid of o > : igeno to provide an anaerobic process. The invention also relates to a method for the biological purification of water in a bioreactor.