WO2003033123A1

WO2003033123A1 - An assembly for circulating water in a waste water tank

Info

Publication number: WO2003033123A1
Application number: PCT/AU2002/001401
Authority: WO
Inventors: John Fox; Errol O'brien
Original assignee: Bushwater Holdings Pty Ltd
Priority date: 2001-10-15
Filing date: 2002-10-15
Publication date: 2003-04-24
Also published as: AUPR825701A0

Abstract

An assembly for a wastewater tank comprising a pump having an inlet for water and air, a conduit for receiving water and air pumped from the pump and a distribution means for receiving water and air from the conduit and distributing it outwardly from the distribution means, whereby water within the tank is circulated from the bottom of the tank to the inlet of the pump in an upper region of the tank.

Description

AN ASSEMBLY FOR CIRCULATING WATER IN A WASTE WATER TANK FIELD OF THE INVENTION

The present invention relates to waste water tanks which are used for storage and treatment of waste water.

BACKGROUND OF THE INVENTION

One type of existing waste water tank consists of a primary and secondary treatment chamber.

Separation of solid particulate matter normally occurs in the primary chamber, while in the secondary chamber bacteria serve to process the waste water to a purer form. The secondary chamber may be aerated to increase aerobic bacteria activity.

One of the problems of existing waste water tanks and treatment systems is their ability to deal with waste water including emulsified oil in a way which is cost effective and practical for use for small scale commercial applications such as service stations . SUMMARY OF THE INVENTION The present invention provides a system for waste water treatment, an assembly for a waste water tank as well as various novel components which may be used in the system and assembly.

The main objective of the present invention is to at least mitigate some of the problems associated with prior art water treatment systems .

According to the present invention there is provided an assembly for a waste water tank comprising a pump having an inlet for water and air, a conduit for receiving water and air pumped from the pump and distribution means for receiving water and air from the conduit and distributing it radially outwardly, whereby water within the tank is circulated from the bottom of the tank to the inlet of the pump in an upper region of the tank.

Preferably the assembly includes a support for supporting the assembly on the bottom of the tank, but it may also float. The conduit preferably interconnects the pump and the distribution means.

The pump may be located above the distribution means . Preferably the pump is adapted to draw water from the water surface in the tank.

Preferably the conduit includes circulation means for inducing a clockwise and counterclockwise flow of water therethrough which may in addition, serve. to break up air bubbles in the waste water (with the result that the air will dissolve more readily) and also to degrade some of the waste in the waste water. In particular, deposits of free oil may be broken up and therefore will emulsify more readily The circulation means may comprise a plurality of vanes .

The circulation means may include a central shaft .

Preferably the vanes are located at spaced locations along the shaft.

The distribution means may comprise a flared surface below the conduit outlet.

The distribution means preferably comprises a nozzle at the outlet of the conduit. It is preferred that the distribution means comprises a conical surface with the apex of the conical surface directly below the outlet of the conduit.

Preferably the support includes the distribution means . The support may include a stand connected to an upper surface of the distribution means.

Preferably the stand comprises legs.

The stand may be connected to parts of the conduit . Preferably the stand includes an upper ring member with part of the conduit located therethrough.

Preferably the assembly includes a filter for filtering at least some solid particulate matter from waste water.

The filter may comprise a cyclone separator for separating free oil from water and from solid particulate matter.

The cyclone separator may comprise an inverted hollow cone.

The assembly preferably includes a waste water outlet for treated water. The treated water outlet is preferably located in a wall of the cyclone separator.

The treated water outlet may be located in an upper region of the cyclone separator.

Preferably the cyclone separator comprises a top surface with holes therethrough.

The top surface preferably comprises an annular disc.

The conduit may be located through the centre of the cyclone separator. The assembly preferably includes a particulate matter outlet at a bottom region of the cyclone separator.

Preferably the assembly includes a tubular portion below the cyclone separator with the particulate matter outlet in a wall thereof. The assembly may be adapted to create a toroidal flow pattern in the tank.

It is preferred that the pump conduit, cyclone separator and distribution means comprise a single unit which may be assembled or disassembled from the individual components.

According to another aspect of the present invention there is provided a separating apparatus for waste water comprising a conical wall with a top wall having a plurality of holes therethrough and an outlet in a lower portion thereof through which at least some separated particulate matter is adapted to pass.

Preferably oil separated by the separating apparatus is adapted to pass up through the holes in the top wall.

The top wall may be oriented as a horizontal planar wall, although any suitable configuration may be used.

Preferably the separating apparatus comprises a central axial region adapted to receive a conduit therethrough.

The separating apparatus preferably includes a tangential inlet through an upper wall thereof, which upper wall is below the top wall.

Preferably the separating apparatus comprises a drain at a bottom region thereof, for draining particulate matter therethrough. According to another aspect of the present invention there is provided a flow distributor for water in a tank comprising a conical upper surface and a lower surface for supporting the flow distributor on the bottom of a tank. Preferably the conical upper surface flares downwardly and outwardly from the apex.

It is preferred that the distributor includes connection means for connecting a stand on an upper surface thereof . Preferably the conical upper surface is an arcuate upper surface.

According to another aspect of the present invention there is provided a system for treating waste water comprising a tank, a waste water inlet, a treated water outlet, a solids waste outlet and an assembly comprising a pump having an inlet for water and air, a conduit for receiving water and air pumped from the pump and a distribution means for receiving water and air from the conduit and distributing it radially outwardly, whereby water within the tank is circulated from the bottom of the tank to the inlet of the pump in an upper region of the tank. The assembly may include a support for supporting the assembly on the bottom of the tank but it may also float.

It is preferred that the individual components of the assembly have one or more of the preferable features previously outlined.

According to another aspect of the present invention there is provided a waste water trap comprising a first chamber for receiving waste water and a. second chamber for receiving particulate matter separated from the waste water, wherein a pump is adapted to pump waste water from the first chamber to a waste treatment tank and a particulate matter drain is adapted to transfer particulate matter into the second chamber and wherein the first and second chambers are isolated from each other.

Preferably the second chamber includes a capture valve which is adapted to close when the second chamber is full allowing excess run off to flow to a stormwater drain. The words "comprising, having, including" should be interpreted in an inclusive sense, meaning that additional features may also be added. BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 shows a tank in accordance with a preferred embodiment of the present invention;

Figure 2 shows a close-up view of a lower part of a water circulation assembly of the tank shown in Figure

1;

Figure 3 shows a close-up view of the upper part of the assembly shown in Figure 1; and

Figure 4 shows a waste water trap for use with the tank shown in Figure 1.

DETAILED DESCRIPTION OF THE DRAWINGS

As shown in Figure 1 a waste water treatment tank 10 is provided with a centrally located water circulation assembly 11 consisting of a pump 12 just below the water level of the tank, a vertical conduit 13 connected to an outlet of the circulation pump 12, a cyclone separator 14 surrounding a major part of the conduit 13 and a water distributor 15 located at the lower outlet 16 of the conduit 13.

The water distributor 15 is a solid conical shaped device having a curved conical upper surface 17 terminating in an apex 18.

The base of the water distributor 15 is preferably flat and has a thickness of approximately 2.5cms .

The upper surface of the water distributor 15 is provided with three evenly spaced anchor points which allow a three-legged stand 21 with feet anchoring brackets to be bolted thereto.

The three-legged stand has generally planar leg elements which terminate in a top annular disc having a horizontal disposition.

It is preferred that the stand 21 serves to support the upper part of the assembly 11 with respect to the water distributor 15, which also acts as a base support . The conduit 13 has a slightly flared outlet opening 23 covering an upper conical section 24 of the water distributor 15.

The conduit 13 extends co-axially along a central axis of both the water distributor 15 and stand 21. At its upper end, the conduit 13 is connected to an outlet of the circulating pump 12.

Above the annular disk 22 the conduit 13 extends through a lower tubular drain section 25 then through the cyclone separator 14 which has the shape of an inverted cone.

The cyclone separator 14 has an internal chamber 26 and an upper horizontally disposed annular shaped disc acting as a top wall 27.

The annular top wall 27 is provided with a number of holes to allow oil particles to pass therethrough.

An upper side wall of the cyclone separator 14 is provided with a waste water inlet 28 which itself is connected to a waste water pipe 29.

Although the inlet 28 is in a side wall just below the annular top plate 22, the inlet may also be provided lower down. At the bottom of the cyclone separator in the tubular drain section 25, a drain outlet 29 is provided above an annular base 30.

The drain 29 is connected to a silt trap which collects particulate matter accumulating at the bottom of the cyclone separator 14.

The circulation pump 12 has an upper surface which draws in water as well as a central air injection inlet 31 which draws in air from above the surface of the water. A treated water outlet pipe 32 is also provided and this extends from a central region just below the outside of the cyclone separator and extends around to an outlet in a side wall of the tank 10.

In operation waste water enters through the waste water pipe 29, under pressure.

The waste water moves in a swirling pattern around the inside chamber of the cyclone separator so that heavier particulate matter falls to the bottom of the cyclone separator into the drain section and water and oil droplets are forced through the openings in the annular disk 22.

Water from the tank and waste water and oil from the cyclone separator are drawn into the circulating pump 12 along with air which passes through the air inlet 31. Waste water including oil droplets and water from the tank is mixed with air to create a mixture of fine bubbles of air, oil droplets and water. This combination is forced through the conduit 13 which is provided with vanes 33 laterally disposed along a central axially extending rod 34.

The vanes are shaped so as to provide alternating clockwise and anticlockwise rotation of the combination as it passes through the conduit 13 so as to emulsify solids.

At the outlet 16 of the conduit 13 the combination of air bubbles, water and oil is forced against the upper surface of the water distributor 15 and accordingly is forced radially outwardly towards the periphery of the inside of the tank 10.

A flow pattern is then created with water, air bubbles and oil passing upwardly to the surface of the water and then around into the circulating pump again. The assembly 11 as described above thus creates a toroidal flow pattern into the circulating pump and out of the conduit 13.

The shape of the water distributor 15 may be modified to vary the direction of the water combination which passes out of the conduit 13. For example a smoother conical tapering upper surface may provide a more gentle and evenly distributed toroidal flow pattern whereas a more severe change in slope for the conical upper surface may result in more of the water combination moving upwardly towards the centre of the tank rather than to the periphery of the tank.

The water outlet 32 is preferably located in a region of the tank where there is minimum circulation of water. This is preferably at a location just below the cyclone separator 14.

However the inlet of this outlet may be located lower down or further up the outside wall 35 which surrounds the circulating pump 12.

The outer cylindrical wall 35 serves to isolate the separated waste water which passes through the annular disc 22, so that it passes into the circulating pump 12. Accordingly the upper edge of this wall 35 is just below the water level of the tank.

It is preferred that a capture pit 40 is provided with a first chamber 41 which is able to capture and retain an effective first flush of waste water. A pump 42 pumps this waste water through the waste water pipe 29 into the tank 10. Particulate matter with waste water is drained through pipe 29 into a second chamber 43 which is located adjacent and isolated from chamber 41. The second chamber forms a silt trap and is provided with a capture valve 44 which closes when the pit is full, allowing excess run off to flow off to a storm drain.

The preferred embodiment of the invention described above may be varied in a number of ways including the replacement of the cyclone separator with an equivalent filtering device which enables oil and waste water to be separated from particulate matter. The location of the circulating pump may also be changed as long as there is an inlet provided to it which is generally centrally located.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or in any other country.

Claims

1. An assembly for a wastewater tank comprising a pump having an inlet for water and air, a conduit for receiving water and air pumped from the pump and a distribution means for receiving water and air from the conduit and distributing it outwardly from the distribution means, whereby water within the tank is circulated from the bottom of the tank to the inlet of the pump in an upper region of the tank.

2. The assembly as claimed in claim 1 wherein the distribution means is configured to distribute water and air radially outwardly.

3. The assembly as claimed in claim 1 or 2 including a support for supporting components of the assembly on the bottom of the tank.

4. The assembly as claimed in claim 1 wherein the conduit interconnects the pump and the distribution means .

5. The assembly as claimed in claim 4 wherein the conduit includes circulation means for inducing a clockwise and/or counter-clockwise flow of water therethrough.

6. The assembly as claimed in claim 5 wherein the circulation means is configured to break up air bubbles in the wastewater.

7. The assembly as claimed in claim 5 wherein the circulation means comprises a plurality of vanes.

8. The assembly as claimed in claim 7 wherein the circulation means includes a central shaft.

9. The assembly as claimed in claim 8 wherein the vanes are located at spaced locations along the shaft .

10. The assembly as claimed in claim 1 or claim 9 wherein the distribution means comprises a flared surface below the conduit outlet .

11. The assembly as claimed in claim 10 wherein the distribution means comprises a nozzle at the outlet of the conduit .

12. The assembly as claimed in claim 11 wherein the distribution means comprises a conical surface with the apex of the conical surface located directly below the outlet of the conduit.

13. The assembly as claimed in claim 3 wherein the support includes the distribution means.

14. The assembly as claimed in claim 13 wherein the support includes a stand connected to an upper surface of the distribution means.

15. The assembly as claimed in claim 14 wherein the stand is connected to parts of the conduit .

16. The assembly as claimed in claim 15 wherein the stand includes an upper ring member with part of the conduit located therethrough.

17. The assembly as claimed in claim 1 including a filter for filtering at least some solid particulate matter from wastewater.

18. The assembly as claimed in claim 17 wherein the filter comprises a cyclone separator for separating free oil from water and from solid particulate matter.

19. The assembly as claimed in claim 18 wherein the cyclone separator comprises an inverted hollow cone.

20. The assembly as claimed in claim 1 including a wastewater outlet for treated water, located in a wall of the cyclone separator.

21. The assembly as claimed in claim 20 wherein the cyclone separator comprises a top surface with holes therethrough.

22. The assembly as claimed in claim 21 wherein the conduit is located through the centre of the cyclone separator.

23. The assembly as claimed in claim 1 or 22 including a particulate matter outlet located at a bottom region of the cyclone separator.

24. The assembly as claimed in claim 23 including a tubular portion located below the cyclone separator with the particulate matter outlet in a wall thereof .

25. A separating apparatus for wastewater comprising a conical wall with a top wall having a plurality of holes therethrough and an outlet in a lower portion thereof through which at least some separated particulate matter is adapted to pass.

26. The separating apparatus as claimed in claim 25 including a central axial region adapted to receive a conduit therethrough.

27. The separating apparatus as claimed in claim 26 including a drain at a bottom region for draining particulate matter therethrough.

28. A flow distributor for water in a tank comprising a conical upper surface and a lower surface for supporting the flow distributor on the bottom of a tank.

29. A system for treating wastewater comprising a tank, a wastewater inlet, a treated water outlet, a solids waste outlet and an assembly comprising a pump having an inlet for water and air, a conduit for receiving water and air pumped from the pump and a distribution means for receiving water and air from the conduit and distributing it outwardly therefrom whereby water within the tank is circulated from the bottom of the tank to the inlet of the pump in an upper region of the tank.

30. A wastewater trap comprising a first chamber for receiving wastewater and a second chamber for receiving particulate matter separated from the wastewater, wherein a pump is adapted to pump wastewater from the first chamber to a waste treatment tank and a particulate matter drain is adapted to transfer particulate matter into the second chamber and wherein the first and second chambers are isolated from each other.

31. The wastewater trap as claimed in claim 30 wherein the second chamber includes a capture valve which is adapted to close when the second chamber is full allowing excess runoff to flow to a stormwater drain.