AU2008205437A1 - Method and apparatus for grey water treatment - Google Patents

Description

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AUSTRALIA

FB RICE CO Patent and Trade Mark Attorneys Patents Act 1990 KATCO HOLDINGS PTY LTD COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Method and apparatus for grey water treatment The following statement is a full description of this invention including the best method of performing it known to us:- 00 2 Cross-Reference to Related Applications b13 ;The present application claims priority from Australian Provisional Patent Application No 2007904369 filed on 14 August 2007, the content of which is incorporated herein by reference.

Introduction The present invention relates to the field of water conservation and in particular the invention provides an apparatus and method for treatment of recycled grey water.

00 SBacknround i Water is a commodity which is rapidly increasing in value due to increasing population, the cost of infrastructure and the variability of weather patterns bringing lengthy periods of droughts which stretch the capabilities of existing storage facilities and make rationing a necessity in many areas. As a result conservation of water has become an issue for many communities and governments are now legislating to impose conservation measures on home owners, including restrictions on non-essential use such as watering gardens and a requirement that new developments include rain water capture and storage facilities.

Conservationists have also argued for some time that re-use should be part of a conservation strategy but legislators have not embraced this approach because of health concerns. However with restrictions on the use of town water, many residents are turning to recycled water to maintain lawns and gardens as well as supplying nonconsumption uses such as toilet flushing, leaving town water for drinking cooking and washing.

Wast water collection systems usually collect two categories of wast water, sewerage or "black water" and waste water from sinks, bath tubs, showers and the like which is known as "grey water". Water authorities will permit the recycling of grey water for applications such as flushing toilets and watering gardens.

Grey water has several undesirable qualities, including: When stored it can generate undesirable odours.

It can promote pathogens and bacteria which can cause disease.

It can leave stains or discoloration.

Impurities such as hair, lint, dirt may be suspended.

A tank holding grey water will develop a slurry of sediment.

Diluted traces of detergents and soaps will be present.

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Because the impurity content of grey water will cause it to rapidly putrefy if ;stored for any length of time without treatment, water authorities generally prohibit the storage of grey water for more than a brief period storage might be permitted for no more than 24 hours).

If grey water is treated it may be permissible to store it for longer periods, but to be accepted by users any system that tries to achieve this should be economical to run, extremely reliable to accommodate everyday use and easily serviceable so the common householder or subcontractor can maintain the system.

00 The average household uses approximately one third of the town supply for toilet flushing and one third on lawn and garden irrigation. Therefore by simply containing the waste shower, bath, hand-basin and washing machine water and re-using it for toilet flushing and irrigation the average household may reduce its water consumption by one third or more. However to fully utilise grey water, storage becomes necessary and this is generally not permissible to the extent required for full usage of recycled water without treatment. This is not feasible if the grey water treatment unit provided is not user-friendly, economical and reliable. Further economy in this context must include both low cost and low power consumption to avoid replacing one environmental problem with another.

Summary A first aspect of the present invention provides a grey water treatment module comprising an ozone source, a diffuser connected to an output of the ozone source and arranged to be submersed in a water storage tank, a primary filter also arranged to be submerged in the water storage tank and located adjacent the diffuser in a path of induced water flow created by ozone flowing from the diffuser.

The module may further comprise a positive displacement pump for drawing water from the water storage tank, and a pressure sensitive switch to operate the pump when a down stream tap is opened causing line pressure to drop. The module may also include a secondary filter.

A second aspect of the present invention provides a method of treating grey water comprising injecting ozone into a storage tank of gray water via a diffuser connected to an output of an ozone source and arranged to be submersed in a water storage tank, locating a primary filter in the water storage tank adjacent the diffuser in a path of induced water flow created by ozone flowing from the diffuser.

The method may also include sensing a pressure drop in an output supply line using a pressure sensing switch and operating a positive displacement pump in 00 4

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response to an output of the sensor when a down stream tap is opened causing line ;pressure to drop, signifying a demand of water to be supplied. Water may be pumped from the water tank into a supply line via a secondary filter using the positive displacement pump.

The pressure is preferably monitored by a pressure switch which operates the positive displacement pump.

The output line may be isolated from the positive displacement pump and the grey water source by a double-check, non-return valve located on the output side of the 00 pump. Water hammer may be reduced by use of a hammer arresting device provided in 00 fluid communication with the outlet of the positive displacement pump. Flow may be iN inspected via a clear view pipe section located in the outlet line, before an output isolation valve. Preferably, water is also further conditioned by a magnetic water conditioner located between the secondary filter and the isolation valve (before or after the clear view section).

Brief description of the drawing An embodiment of the grey water treatment module will now be described in greater detail, by way of example, with reference to the accompanying drawing in which a grey water treatment system is schematically illustrated.

Detailed description of a grey water treatment system Referring to Figure 1, a grey water treatment module for the filtration and sterilisation of grey water is illustrated. The module is illustrated connected to a catchment tank 26 in which grey water is stored for re-use for toilet flushing and lawn and garden irrigation. Water taken from household sources such as the hand-basins, shower and bath drains and washing machine waste water are all directed to the grey water storage tank 26 for treatment and re-use.

Such an arrangement can lead to savings of in the order of one third of a household's water usage from the town or external water supply on average.

Preferably the positive displacement pump 14 is especially suited for use with grey water and the impurities it contains and is specifically designed to ameliorate difficulties related to the transfer of water containing lint, hair, dirt, detergents and other undesirable contaminants.

The preferred embodiment of the grey water treatment module 29 is manufactured as a stand-alone unit comprising of a combination of components within a compact housing, but understandably it must work in conjunction with other external 00 components such as a grey water storage tank 26 with its own inflow point ;overflow 27 and supplementary external water supply 28.

The grey water treatment module 29 includes an ozone generator 11 with delivery tube 31 and diffuser 32 for locating in the grey water tank 26. A filter 12 is connected to the diffuser 32 for 'inside the tank' installation such that water circulation induced by ozone bubbling from the diffuser 32 is drawn through the filter 12 to provide primary filtration of the grey water while the ozone kills pathogens in the water. A foot valve 13 and suction pipe 33 connected to a positive displacement, self 00 priming electric pump 14 draw water from the grey water storage tank 26. A hammer Sarrester comprising a pressurised air tank 15 is connected to an outlet of the pumpl4.

I A 20mm drain valve 16 is provided from the outlet of the pump 14. The outlet of the pump 14 is also connected to a canister filter housing and filter cartridge 18, a 'dualcheck', non-return valve 21, a stop-start electric pressure switch 22 with 10-12 second delay, a clear section of pipe 23 for visual indication of flow, a magnetic water conditioner 17 and a 20mm isolation valve 24 in series, leading to a 'take-off point 34.

A pressure gauge 19 is fitted to the filter 18, and a bypass pressure sensitive valve fitted to the output side of the filter 18 returns water to the grey water storage tank 26 via a return tube 35 when pressure increases above a set-point of the bypass valve due to sudden shutoff of a downstream valve.

A valve 39 is provided to supply town water to the grey water tank 26 when the level drops below a minimum level at which the weighted float 36 is exposed causing the valve 39 to open. The minimum level is set so that the in-tank filter 12 and diffuser 32 are always covered by enough water to operate, such that treated toilet flushing water is always available.

The grey water treatment module 29 provides sterilisation and filtration functionality to improve the quality of the water in the grey water tank 26 including continually injecting ozone enriched air into the stored capacity. The induced flow through the in-tank filter 12 provides the first stage of filtration which assists with the removal of most grey water particle impurities and which in turn helps the pump unit 14 to perform reliable suction lift for water delivery to the second stage filter 18.

The ozone source 11 comprises an air pump 37 and an ozone generator UV light assembly 38 located in the air flow path of the air pump which creates a proportion of ozone (03) in the generated air flow. The ozone enriched air is injected into the grey water storage tank 26 via an ozone delivery tube 31 to the diffuser 32 where it sterilises the grey water. The bubbling of ozone enriched air from the diffuser 32 also induces a circulation of the water in the tank 26 which provides greater contact of contaminants 00 6

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in the water with the ozone. The induced circulation also facilitates the in-tank ;filtration operation by drawing the water through the in-tank filter 12.

The pump 14 then lifts and delivers the ozone treated grey water to the secondary filter 18 which in turn completes the filtration of the grey water before it reaches the electric pressure switch 22 which provides the stop-start automatic pressure switch function for the pump 14 in response to a valve being opened down stream of the grey water treatment module 29. This filtration of the supply before it reaches the stop-start pressure switch improves the reliability of operation of pressure switch by removing contaminants that may interfere with operation of the valve.

SThe stop-start pressure switch includes a time delayed output which permits the N pump 14 to keep running for a period of approximately 10-12 seconds after the water flow has stopped. This allows water to return to the grey water storage tank 26, via the bypass valve 20 and a backwash tube 35, to create turbulence in the bottom of the tank 26 to eliminate sediment build-up near the foot valve 13 which is the suction point of the pump 14. After the short time delay has timed out the pump 14 will turn off.

Filtration and ozone injection continues inside the grey water storage tank throughout this pumping process.

The combination of these components together provide a reliable and economical grey water treatment and pumping unit which can supply treated water which can be utilized for toilet flushing and irrigation.

Key components of the preferred grey water treatment unit are: Two independent filters with large surface area filter element cartridges which are easily accessible for cleaning or replacement. One pump with low power consumption (.37kw) which has been specially selected due to its characteristics for suction lift, dirty water pumping, positive displacement, self priming and quietness when operating.

One ozone generator which requires no added chemicals and operates quietly with a low power consumption while continually sterilizing the stored grey water in the holding tank.

An electronic stop-start pressure switch which provides the start-up instruction to the pump on demand, this is installed in such a way that it is supplied with a clean water supply via the two filters which ensures reliability.

The reliability of each component incorporated in the preferred grey water treatment unit is protected by other components of the unit, The grey water in the tank 26 is pre-filtered before it reaches the pump 14.

The pre-filtered water provides reliable pump operation.

The secondary filter 18 provides clean water to the stop-start pressure switch 00 7

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In addition the reliable operation of the stop-start pressure switch provides a ;daily supply of treated water for toilet flushing and irrigation. The ozone injection sterilises the grey water killing pathogens and eliminating unwanted odours, and the possibility of bacteria.

The grey water treatment unit may be used with various sized grey water storage tanks depending on site conditions and the size of the dwelling to which it is connected.

The ozone generator delivers an ozone enriched air supply to the grey water storage tank. This ozone supply is dispersed inside the grey water storage tank by a 00 diffuser located inside a large capacity filter element suspended above the bottom of the 00 Stank immersed continually in the grey water supply. On demand the electric pump is i activated by the stop-start pressure switch and draws grey water from the storage tank via the non-return valve and suction pipe. A pressurised air tank is used for installation to the top of the pump to reduce water pulsation and water hammer. The water then passes through pipe-work via a tee fitting. One direction of the water flow from the tee goes to a 20mm drain valve used for releasing water when servicing the filter element.

The other direction of the water flow from the tee enters the canister filter housing fitted with a replaceable filter cartridge. Filtered water exiting the canister filter is then directed pass a 'tee' fitting which connects to a bypass pressure sensitive valve. This valve has a tube connected on the relief side which returns to the grey water storage tank. The main flow supply exiting the 'tee' allows the flow to continue through a dual-check valve then to the stop-start pressure switch. After stop-start pressure switch water flows through a short section of clear pipe work which is used as a visual indicator before passing through a length of pipe shrouded in a magnetic water conditioner and then passing to an isolation valve which can be turned off when filter cleaning needs to be carried out. In addition a tank filling level sensitive float valve is provided to maintain a minimum level in the grey water storage tank which should be above the ozone diffuser and 'in-tank' filter at all times.

Status of the grey water treatment module is monitored by a status monitor 41 having at least two inputs. A first fluid-pressure transducer 42 is located in the ozone line 31 extending from the ozone generator 11 and is connected to one input of the status monitor 41. A second fluid-pressure transducer 43 is located in the output line 47 of the water pump 14 and is connected to another input of the status monitor 41.

The status monitor 41 includes under and over pressure circuits to detect out-oftolerance signals from the fluid pressure transducers 42 and 43 and warning lights 44 on a front panel of the status monitor (and visible from outside the housing of the grey water treatment module) indicate when the pressure signals are out of tolerance. A 00 8 communications output is also provided in the status monitor 41 to which a communications line 46 is connected to communicate with a central monitoring facility which may be a monitoring station located in a house or other nearby building associated with the grey water storage tank, or may be a remote monitoring facility in which case the communications line may be a telephone line and communications may be via a DSL channel or via a dial-up function that makes connection on an as needed Cc, basis.

It will be appreciated by persons skilled in the art that numerous variations 0 and/or modifications may be made to the invention as shown in the specific Sembodiments without departing from the spirit or scope of the invention as broadly N described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (19)

1. A grey water treatment module comprising an ozone source, a diffuser connected to an output of the ozone source and arranged to be submersed in a water storage tank, a primary filter also arranged to be submerged within the water storage tank and located adjacent the diffuser in a path of induced water flow created by ozone flowing from the diffuser.

2. The grey water treatment module as claimed in Claim 1 further comprising a 00 positive displacement pump for drawing water from the water storage tank, and a 00 pressure sensitive switch in fluid communication with the output of the pump to operate N the pump when a output line pressure drops.

3. The grey water treatment module as claimed in Claim I or 2 comprising a secondary filter.

4. The grey water treatment module as claimed in Claim 1, 2 or 3 wherein the secondary filter is located on the output side of the positive displacement pump.

The grey water treatment module as claimed in Claim 1, 2, 3 or 4 wherein the output line is isolated from the positive displacement pump and the grey water source by a double-check, non-return valve located on the output side of the pump.

6. The grey water treatment module as claimed in Claim 1, 2, 3, 4 or 5 wherein a hammer arresting device is provided in fluid communication with the outlet of the positive displacement pump to reduce water hammer.

7. The grey water treatment module as claimed in any one of Claims 1 to 6 comprising an outlet isolation valve located on the output side of the pump to isolate the grey water source from the supply line.

8. The grey water treatment module as claimed in claim 7 wherein the isolation valve is a manual valve.

9. The grey water treatment module as claimed in claim 7 wherein the isolation valve is a double-check, non-return valve.

The grey water treatment module as claimed in any one of Claims 1 to 9 comprising a clear view pipe section located in the outlet line, before an outlet isolation valve, and through which flow may be inspected.

11. The grey water treatment module as claimed in any one of Claims I to comprising a magnetic water conditioner located between the secondary filter and the isolation valve.

12. A method of treating grey water comprising injecting ozone into a water storage tank of gray water via a diffuser connected to an output of an ozone source and OO 00 O arranged to be submersed in a water storage tank, locating a primary filter in the water ;storage tank adjacent the diffuser in the path of induced water flow created by ozone flowing from the diffuser.

13. The method of claim 9 further comprising sensing a pressure drop in an output supply line using a pressure sensing switch and operating a positive displacement pump in response to an output of the sensor when an output line pressure drops.

14. The method of claim 12 or 13 further comprising pumping water from the water tank into the supply line via a secondary filter using the positive displacement pump.

The method as claimed in any one of claims 12 to 14 comprising passing water Ofrom the output of the positive displacement pump through an output isolation valve located on the output side of the pump to isolate the grey water source from the supply line.

16. The method as claimed in claim 15 comprising passing water in the supply line through a clear view pipe section located before the output isolation valve.

17. The method as claimed in any one of claims 12 to 16 comprising reducing water hammer use of a hammer arresting device in fluid communication with the outlet of the positive displacement pump.

18. The method as claimed in any one of claims 12 to 17 comprising conditioning the water using a magnetic water conditioner located between the secondary filter and the output isolation valve.

19. A grey water treatment system substantially as hereinbefore described with reference to the accompanying drawing. A method as claimed in claim 1 substantially as hereinbefore described with reference to the accompanying drawing.