APPARATUS FOR TREATING WATER

Abstract

An apparatus (12) for treating water, in particular for removing surfactants from waste water, includes a vessel (14), defining an inlet (16) for receiving waste water containing air bubbles, and an outlet (20) for the exit of water, following treatment. Inside the vessel there is at least one tubular member (50) having a lower open end (52) into which the flow of waste water from the inlet may be directed in use. The tubular member (50) extends from the inlet towards a top of the vessel where an upper exit (54) from the tubular member is defined. In use, most un-aerated water entering the vessel through the inlet can exit the tubular member at the lower open end. Foam formed in the water by the air bubbles may travel up the tubular member to the upper exit, which is preferably located above the water level (60) in the vessel.

Claims

1. An apparatus for treating water, in particular for removing surfactants from waste water, comprising. a vessel, defining an inlet for receiving waste water containing air bubbles, and an outlet for the exit of water following treatment; and at least one tubular member having a lower open end into which the flow of waste water from the inlet may be directed in use, the tubular member extending from the inlet towards a top of the vessel where an upper exit from the tubular member is defined, wherein, in use most un-aerated water entering the vessel through the inlet can exit the tubular member at the lower open end, foam formed in the water by the air bubbles may travel the tubular member to the

2. An apparatus for treating water as claimed in claim 1 wherein the tubular member includes a plurality of turns so as to define a serpentine path for the transport of fluids through the tubular member.

3. An apparatus for treating water as claimed in claim 2 wherein the serpentine path includes at least two turns.

4. An apparatus for treating water as claimed in claim 1 wherein the tubular member defines a further aperture positioned along its length between the serpentine path and the upper exit, for the egress of un-aerated water from the tubular member.

5. An apparatus as claimed in claim 4 wherein the tubular member includes a junction where it joins an generally upwardly extruding tubular portion at an angle, with lower end of the upwardly extending tubular portion defining the further aperture.

6. An apparatus as claimed in claim 1, wherein the tubular member defines a generally horizontally extending portion in which the exit of the tubular member is defined and wherein the horizontally extending portion extends generally tangentially to the exterior of the vessel so that tile exit deposits foam generally tangentially to the exterior of the vessel to induce rotation in the vessel.

7. An apparatus as claimed in claim 1, wherein the horizontal portion of the tubular member is undercut at the exit, at an angle of about 45° to the horizontal.

8. An apparatus as claimed in claim 1 wherein the inlet is defined at or adjacent the base of the vessel and comprises an inlet tube having a smaller diameter than that of the tubular member and whose end is located inside the tubular member.

9. An apparatus as claimed in claim 1, wherein the outlet for the exit of waste water is defined in the base of the vessel.

10. A tubular member for use in an apparatus for treating water the tubular member defining: an inlet or first open end into which a flow of waste water may be directed in use; a main outlet at a second end distal from the inlet: a serpentine portion having at least one bend, and preferably plurality of bends which extends away from the inlet; a junction portion where the tubular member defines a change in direction and a further aperture or outlet; wherein the main exit of the tubular member is defined in a portion of the tubular member which extends generally perpendicularly to the Serpentine portion.

11. A tubular member as claimed in claim 10 wherein the junction portion comprises a tubular portion intersecting a second tubular portion at an angle with one end of the second tubular portion defining the further aperture/outlet.

12. A tubular member as claimed in any one of claim 10 wherein the tubular member defines an initial short straight tubular portion, a series of bends typically a first bend through about 45° followed by three or more bends through about 90°, which serpentine portion intersects a further tubular portion at an angle, one end of the further tubular portion defining the further aperture, the further tubular portion turning through 90° the main outlet being defined at the end of the further tubular portion.

12. (canceled)

13. The use of an apparatus as claimed in claim 1 in a process for treating waste water containing surfactants, to remove surfactants by causing the formation of foam by the injection of gas into the waste water and by separating that foam from the water using the apparatus.

14. A method for treating water, in particular for removing surfactants from waste water, using an apparatus comprising: a vessel, defining an inlet for receiving waste water, and an outlet for the exit of water, following treatment; and through the inlet tends to exit the tubular member at the lower open end, and foam formed in the water by the air bubbles travels up the tubular member to the upper exit, which, in use, is located above the water in the vessel; recirculating water from the outlet via the venturi to inject more air into the water and passing the aerated water back into the vessel via the inlet for a period of time; and allowing foam to exit the vessel via the upper exit.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0049] Specific embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0050] FIG. 1 is a schematic drawing illustrating elements of a system for treating grey water;

[0051] FIG. 2 is a schematic view of a bubble separator of the system;

[0052] FIG. 3 is an isometric view illustrating the arrangement of four tubular members in a vessel of the system shown in FIGS. 1 and 2;

[0053] FIG. 4 is a side view of the arrangement shown in FIG. 3;

[0054] FIG. 5 is a top plan view of the arrangement shown in FIG. 3;

[0055] FIG. 6 is a side view of a tubular member of the type shown in FIG. 3; and

[0056] FIG. 7 is a perspective view of the tubular member shown in FIG. 6.

DESCRIPTION OF EMBODIMENTS

[0057] Referring to the drawings, FIG. 1 is a schematic view of a water treatment system 10 which includes an apparatus for removing surfactants from the water, also referred to as a “bubble separator ” 12. The bubble separator 12 includes a vessel 14 which is the form of an upright generally cylindrical tank which has a water inlet 16 in its base 18 and an outlet 20, also in its base 18. There is an exit/outtake for foam 22 at the top of the tank. The tank is connected by tubing 24 to a recirculation loop including a pump 26 and a venturi air intake 28 and to a carbon filter 30, as well as a water exit from the system 32.

[0058] FIG. 2 shows the bubble separator 12 only, which includes a single tubular member 50 having a generally annular cross-section which extends from one lower open end 52 near the base 14 of the vessel to another open end 54 near the top 56 of the vessel. As can be seen in FIG. 2, the water inlet 16 is in the form of a short tube 58 which projects into the interior of the vessel and also a small distance inside the lower open end of the tubular member 50. The inlet tube typically has a smaller diameter than the tubular member of about 15mm compared to the tubular member which has a diameter of about 50mm. FIG. 2 also shows the typical water level 60 of the vessel, in use, above which foam 62 is present, the water level also defining a water/foam interface.

[0059] As shown in FIG. 2, the tubular member 50 defines a serpentine path along which fluid may travel upwards through the vessel. (The tubular member 50 is also shown separate from the vessel in FIGS. 6 and 7). In particular the tubular member defines a 45° turn/bend 70 before defining three consecutive 90° turns/bends, 72, 74, and 76. After the last 90° turn, the tubular member defines a junction 78 where the tubing joins with a cross-piece 80 at an angle of 45°. The cross-piece 80 is aligned to extend vertically upwards. The lower end 82 of the crosspiece extends a short distance below the junction and is open. The vertical cross-piece extends a short distance before the tubular member turns through a final 90° bend 84. That is followed by a short horizontal portion 86, before reaching the outlet 54 of the tubular member which is cut at a plane which is 45° to the vertical

[0060] FIGS. 3 to 5 show a preferred arrangement of four tubular members 50 in the vessel. The side walls and top of the vessel are omitted in order to show the tubular members in more detail, each of which is the same as the tubular member shown in FIG. 2. In particular, with reference to FIG. 5, it can be seen that the tubular members are arranged around the edges of the tank in an annulus/ plane which is generally perpendicular to the radius of the tank (i.e. tangentially), as is the exit for the foam at the top of the tubular member so that any foam leaving the exit 54 is gently encouraged to flow in a circular path around the vessel on top of the water surface.

[0061] In use, grey water passes into the system and is aerated with the venturi 28 which vigorously introduces large quantities of air into the grey water before the water enters the vessel 14. The volume of water and air can be adjusted for optimum operation of the system depending on various parameters, but typically the flow rate of water into the system may be in the order of 30 litres per minute and air may be injected at a rate of between 3 and 20 litres per minute, e.g. 10 litres per minute. Ozone is preferably also injected into the water in low concentrations to improve system performance and oxidise malodourous compounds. The aerated water enters the vessel at the base of the vessel via the inlet tube which ends inside the tubular member near its open lower end.

[0062] The air entering the waste water forms bubbles which are then sheared into smaller bubbles preferably by the use of a static mixer (not shown). The surfaces of these bubbles become coated in a mono layer of detergent molecules arranged so that their hydrophobic portions generally face the air inside the bubble and their hydrophilic portions face the body of the water. Organic material and particulate in the grey water also adsorb onto the surface of those bubbles.

[0063] The mixture of waste water and air then enters the bubble separator 12 via the narrow inlet tube 58 into the lower portion of the tubular member 50 which has a much greater cross-sectional area. Because the inlet tube 58 is considerably narrower than the tubular member, the velocity of the water will drop as it enters the tubular member 50 and most of the un-aerated water, which is denser than the aerated water, will tend to escape under gravity though the opening at the lower end of the tubular member.

[0064] The flow of aerated water then turns through about 45° before passing through three 90° turns forming a serpentine path. These bends provide good contact between the remaining air and water streams and encourage water to separate and any air bubbles to form foam. The flow then passes to the “T- junction” which provides the downward facing exit located below the water/foam interface. This allows any water which has separated from the foam to escape under gravity as it is denser than the foam. The foam continues to travel up the tubular member along the vertical section before passing though the final 90° bend along a horizontal portion of the tubular member and though the outlet. The 45° cut on the outlet 54 encourages gentle deposition of the foam onto the foam/water surface. As the layer of foam 62 on top of the water level 60 grows in height it will eventually exit via the foam outtake 22. The foam layer is mostly “dry” as most of the water drains out of the foam as it rises through the tubular members 50. The foam which exits the bubble separator gradually collapses and can be fed to the sewer using a small amount of carried over water.

[0065] During this time the water is continuously circulated in a loop into the vessel 14 and out through the outlet 20 to the venturi where air is injected into it at the desired rate before being injected back into the vessel. Foam exits the vessel from the exit 22 at a volume rate generally equal to the rate that air is injected into the water flow by the venturi. After a period of time the process is stopped. Although there will be some foam still floating on top of the water which has not been forced through the exit 22, the amount will be insignificant.

[0066] The treated water is then pumped out of the vessel 14 into a tank 100 containing a carbon filter 30 for final removal of particulates via an inlet 102. The water exits the tank after a predetermined period via the same inlet/outlet 102 at the base of the tank. The filtered water may then be further treated using a UV lamp and then stored in a tank for use (e.g. for flushing toilets, garden irrigation or the like).

[0067] Although the FIGS. 3 to 5 show a bubble separator having four tubes, it will be appreciated that the chamber may include fewer tubes, for example embodiments which include one two or three tubes are envisaged as well as embodiments having more than four tubes. Also the number of bends in the chimney may vary from that shown in the drawings.

[0068] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.