Water purification reactor

Abstract

Water purification reactor comprising a cylindric tank (10) with a vertical length axis (), arranged with a water inlet (11) and a water outlet (12). The reactor exhibits a first (L) and a second (U) vertically separated annular zone, defined by an internal wall () of the tank (10) and the external wall of a centrally arranged tube element (15) running from the tank bottom (14) to a level within the upper annular tank zone (U), the tube element (15) forming a fluid connection between the two annular zones (L,U), the inlet to the assembly being located in the lowermost annual zone (L) while the outlet from the assembly is located in the uppermost annular zone (U), while nozzles (22) are arranged at the bottom end of the tube element (15) for the generation of microbubbles therein.

Description

[0001] Water purification reactor

[0002] The present invention relates to a device for improving the quality of water in general and to maintain a high water quality in aqueous systems. More specifically, the present invention concerns a water purification reactor as indicated by the preamble of claim 1.

[0003] Background

[0004] It is widely recognized that water quality in aquaculture plants is of primary importance with regard to growth and health for the marine species and thereby also the economy of the plants. Impurities that accumulates over time and reduced oxygen concentration are problems that must be handled in order to obtain a sound environment and a sound economy.

[0005] Purification of water from various impurities may be conducted by blowing air or gas bubbles through a container in which the water is located, so that impurities with affinity for the surface of the gas bubbles adhere to these and are transported to the water surface where the impurities is "skimmed off". These are well established facts.

[0006] The impurities can be of a quite different nature, but will often include particles of organic material that both represent a contaminant in themselves but also have the potential to attract bacteria that can eventually pose a greater threat if not removed from the water.

[0007] Although flotation processes have been known and used for a number of years, there is still room for and desire for improvements in this area, in order to satisfy increasingly stringent requirements for the absence of pollution of the environment around industry and households as well as a general desire of making more efficient and less space-requiring and less water-consuming equipment.

[0008] From CN 101219837, a method for treating wastewater involving flotation and the use of ozone is known, as the ozone is specifically designed to destroy oil contaminants in the water.

[0009] WO publication no. 02 / 096808 deals with a wastewater treatment plant where flotation is used in combination with ozone to reduce COD (Chemical Oxygen Demand).

[0010] US patent No. 6 126 842 deals with the same problem as the aforementioned WO publication and with mainly the same means.

[0011] JP 58177199A also describes a wastewater treatment method involving flotation, and it is emphasized that the ozone treatment used here is an ultrasonic ozone treatment. Norwegian Patent No. 333457 concerns a method and device for treatment of waste water involving a combination of the technics including flotation, use of multiphase pumps and static mixers and addition of oxidizing medium such as ozone, the device being quite comprehensive and voluminous.

[0012] Despite all the efforts that have been made in this area, there is still a need to make water treatment more effective, in particular in relation to large water consumers found in the aquaculture industry.

[0013] Objective

[0014] It is therefore an objective of the present invention to provide a device and / or method for efficient water purification useful in particular in the aquaculture industry.

[0015] It is a derived objective to achieve the above mentioned objective using compact equipment in relation to the water flow rates to be treated.

[0016] It is a derived objective to achieve improved fish health in aquaculture production plants.

[0017] It is yet another objective to obtain the same using equipment which requires little maintenance, and which is comparatively inexpensive in production and use.

[0018] The present invention

[0019] The above indicated objectives are achieved by the present invention in the form of a water purification reactor as defined by claim 1.

[0020] While the present invention is related to the reactor and its specific design, the use of the tank is understood to include addition of an oxidizing agent such as ozone, that is added to the water, typically upstream of the tank inlet, allowing the ozone to start oxidizing undesired components in the water at the latest when entering the tank.

[0021] The water purification reactor is a one-tank system in which the water to be treated is guided through the assembly in a highly efficient manner involving circular flow and vertical flow with continuous addition of micro-bubbles. The present invention represents an integration of a number of process-zones including inlet / distribution, contact, reaction, flotation, and separation within a single compact reactor structure. The reactor removes particles and microparticles, reduces turbidity, and reduces the concentration of bacteria and viruses. In relation to use in aquaculture production plants, these benefits mean improved growth and fish health and ultimately improved economy at a modest cost. The reactor is significantly more efficient with regard to space utilization than the device according to NO 333 457 Bl.

[0022] Below, the present invention is described in further detail in the form of a non-limiting embodiment illustrated by the accompanying drawings.

[0023] Figure 1 is a schematic and simplified side sectional view of an embodiment of the present invention.

[0024] Figure 2 shows a horizontal cross-section of the reactor of Figure 1 at the broken line / / - / / .

[0025] Figures 3a, 3b show horizontal cross-sections of the reactor of Figure 1 at the broken line Ill-Ill, illustrating slightly different variants.

[0026] The drawings are schematic and simplified which means that some proportions may be out of scale and that elements typically present in an operative device may be omitted from the drawings for the sake of simplification and focus on the novel elements of interest.

[0027] Figure 1 is a side view of a reactor according to the present invention. The view is mostly sectional but shows some elements out of the plane of the section. A main constituent of the reactor is the tank 10 which is generally cylindric with a vertical axis. The tank 10 has an inlet opening 11 shown to the right and an outlet opening 12 shown to the left. It is not a requirement that the inlet and the outlet openings are at opposite sides of the tank from one another.

[0028] Along the centre axis x of the tank a tube element 15 is arranged, extending from the bottom 14 of the tank 10 to a level above. Further down in the description, three vertical zones are discussed within the tank, an annular lower zone L, an annular middle tank zone M and an upper tank zone U, the latter being substantially cylindrical in shape. In addition to these vertically separated tank zones, there is an additional zone T within the tube element 15. The top of the tube element 15 constitutes a border between the middle tank zone M and the upper tank zone U. At a first lateral side from the inlet opening 11, a vertical perforated plate 16 is arranged. This perforated wall is slightly "behind" the paper plane of the drawing. The main function of the perforated wall is to spread the flow of water evenly over the cross-section of the flowpath within the tank.

[0029] Also shown is a vertical fluid tight plate 17, arranged at another lateral side of the inlet opening 11, i.e. in front of the paper plane of the drawing. Both plates 16 and 17 extend vertically from the tank bottom 14 up to a fluid tight annular disc 18, arranged horizontally to physically separate the lower tank zone L from its middle tank zone M. In the horizontal direction, both plates 16 and 17 extend from an external wall of the tube element 15 to an internal wall 13 of the tank 10. It is worth noticing that the inlet opening 11 is in the lower tank zone L while the outlet opening 12 is in the middle tank zone M.

[0030] The tube element 15 has an inlet opening 20 in the lower tank zone L and an outlet opening 21 at the border between the middle tank zone M and the upper tank zone U. Above the horizontally arranged fluid tight annular disc 18, a, perforated disc 19 is shown, arranged horizontally below the outlet opening 21 of the tube element 15.

[0031] The perforated disc 19, as well as the perforated plate 16, has the primary function of ensuring a distributed, even flow throughout the cross-section of the relevant part of the tank, thereby ensuring a homogenous flow, avoiding that some parts of the entering water are conveyed more rapidly through the tank than other parts.

[0032] At the bottom of the tube element 15, a plurality of nozzles 22 or the like are arranged to allow introduction of micro-bubbles into water within the tube element, to enhance the flotation of particles residing therein. While not evident from Figure 1, the nozzles 22 are typically distributed over the entire circular area of the lower end of the tube element 15. The nozzles can be of any convenient type, such as e.g. static mixers.

[0033] At the top of the tank 10 a skimming device 23 is arranged for periodic or continuous skimming of impurities 24 brought to the surface by the microbubbles. The impurities (24) may be removed through a discharge chute or conduit 25 for optional later treatment. This may be conducted using well known equipment and is not described in further detail here.

[0034] While the invention is not restricted with regard to size, a typical size of the tank would be a height of about 3-5 meters and a diameter of 1 to 1.5 meters.

[0035] Now turning to Figure 2 which is a horizontal sectional view taken 2t the line / / - / / in Figure 1. A water flow WF that enters inlet opening 11 will pass through the perforated plate 16 and flow in a mainly laminar flow in a circular manner around the tube element 15 until it reaches the inlet opening 20 of the latter. The liquid-tight plate 17 ensures that no water can travel the shorter distance between the inlet 11 of the tank to the inlet 20 of the tube element 15. Upon reaching the inlet 20, the water will enter the tube element 15 and flow in a vertical upwards direction under the influence of microbubbles induced at or by the nozzles 22. Presence of bubbles is indicated within the tube 15. Figure 3a is horizontal sectional view at the line Ill-Ill of Figure 1, illustrating an embodiment of the perforated annular disc 19. While just a few dozens of circular perforations are shown, there may be thousands in a real life embodiment of disc 19.

[0036] Figure 3b shows a variant of the disc 19 in which the perforations have the form of longitudinal slits rather than circular openings. It should be noted that even the perforated plate 16 may have perforations as discrete circular openings as well as longitudinal slits.

[0037] In use, water is charged to the inlet opening 11, becomes distributed by the perforated plate 16 to the entire cross-section of the annular lower zone L, whereafter it flows in a circular motion around the tube element 15 and enters the inlet opening 20. From here, the water flow is vertically upwards within the tube element 15 while exposed to micro-bubbles added by the nozzles 22 at the bottom of the tube element 15. Optionally, ozone and / or other ingredients may be added at the bottom of the tube element to enhance the flotation of particulates in the water.

[0038] While the lightweight bubbles with adhered particles continues upwards to the surface of the water in the upper tank zone U, purified water flows out from the outlet opening 12 with a flow rate corresponding to the flow rate of the entering water.

[0039] Independent, confidential tests of the reactor in combination with various concentrations of ozone, by an independent 3rdparty service provider, have demonstrated positive results on parameters like germ-count, turbidity, colour and total organic carbon (TOC).

[0040] List of drawings elements

[0041] 10 tank

[0042] 11 tank inlet opening

[0043] 12 tank outlet opening

[0044] 13 internal tank wall

[0045] 14 tank bottom

[0046] 15 tube

[0047] 16 perforated vertical plate

[0048] 17 liquid tight vertical plate

[0049] 18 liquid tight horizontal annular disc

[0050] 19 perforated horizontal annular disc

[0051] 20 tube inlet opening

[0052] 21 tube outlet opening

[0053] 22 nozzles

[0054] 23 skimming device

[0055] 24 impurities

[0056] 25 discharge chute (for impurities

Claims

Claims1. Water purification reactor comprising a cylindric tank (10) with a vertical length axis (), arranged with a water inlet (11) and a water outlet (12), characterized in that the tank exhibits three vertical tank zones, an annular lower tank zone (L), an annular middle tank zone (M) and an upper tank zone (U), the lower tank zone (L) and the middle tank zone (M) being separated by a horizontal annular, fluid-tight disc (18), each annular tank zone further being defined externally by an internal wall (13) of the tank (10) and defined internally by a centrally arranged tube element (15) running from a tank bottom (14) to a level constituting a border between the middle tank zone (M) and the upper tank zone (U), the tube element (15) forming a fluid connection between the lower tank zone (L) and the upper (U) and middle (M) tank zones, the inlet (11) to the reactor being located in the annular lowermost zone (L) while the outlet (12) from the reactor is located in the annular middle tank zone (M), while nozzles (22) are arranged at the bottom end of the tube element (15) for the generation of microbubbles in the tube element (15).

2. Water purification reactor according to claim 1, wherein the centrally arranged tube element (15) has an inlet opening (20) at its lowermost end and outlet opening (21) at its uppermost end.

3. Water purification reactor according to claim 1 or 2, further comprising a vertically arranged perforated plate (16) extending between the internal wall of the tank (10) and the external wall of the tube element (15), from the tank bottom (14) to the top of the annular lower tank zone (L) in the flow direction between the inlet (11) to the tank (10) and the inlet (20) to the tube element (15).

4. Water purification reactor according to claim 3, further comprising a vertically arranged, fluid tight plate (17) extending between the internal wall (13) of the tank (10) and the external wall of the tube element (15), from the tank bottom (14) to the top of the annular lower tank zone (L), arranged to prevent the water flow from shortcutting the perforated plate (16).

5. Water purification reactor according to any one of the preceding claims, further comprising a horizontally arranged perforated annular disc (19) extending between the internal wall (13) of the tank (10) and the external wall of the tube element (15), above the outlet opening (12) of the tank.

Images