WO2004046474A1

WO2004046474A1 - Improvements in or relating to water recycling systems

Info

Publication number: WO2004046474A1
Application number: PCT/GB2003/005089
Authority: WO
Inventors: Paul Williams
Original assignee: Gramm Environmental Limited
Priority date: 2002-11-21
Filing date: 2003-11-21
Publication date: 2004-06-03
Also published as: GB0227225D0; AU2003302131A1

Abstract

A filtering apparatus and method for use in a recycling system comprising a filter (30) and means for the generating an upward flow of water through the filter (30). The upward flow is preferably generated by positioning the filter on the upper surface of a pipe (29) joining a pipe (23) having a downwardly inclined portion upstream of the filter (30) and pipe (8) having an upwardly inclined portion downstream of the filter (30), thereby creating a head of water in the pipes to force water upwardly through the filter. A jetting means (44) is used to spray water down onto the filter to clean it. The apparatus is disinfected using a disinfecting apparatus.

Description

IMPROVEMENTS IN OR RELATING TO WATER RECYCLING SYSTEMS

The present invention relates to improvements in or relating to water recycling systems. In particular, the present invention relates to a filtering and/or disinfecting apparatμs and method for a water recycling system and to systems suitable for recycling water, such as wash water, in a domestic or industrial environment including such filtering and/or disinfecting apparatus.

Toilets in a building are generally flushed with water supplied directly from the mains water supply. There is no necessity for such water to come directly from the mains water supply and waste or grey water from, say, baths, showers or wash basins could be used for such a purpose. To reduce the amount of mains water to be supplied for flushing toilets it would be desirable to provide a way by which waste water could be recycled for this purpose.

WO 97/02388 describes a water recycling system in which waste water from a bathroom drains into a collection tank through a filter situated in an upper region of the tank. Waste water is then pumped into an elevated header tank via a supply pipe and the header tank contains a disinfectant dispenser which supplies disinfectant to the contents of the header tank. A proportion of the pumped waste water is sprayed on to the filter to disinfect it.

A problem with this system is that the collection tank is disinfected by relying on a back flow of disinfected water from the header tank into the collection tank after pumping has ceased. Furthermore, a tall collection tank is required for the water recycling system. Also, removal of the filter to clear out particles which collect therein is periodically necessary.

It is therefore an object of the present invention to at least partially overcome at least one of the problems of the above-mentioned system.

According to one aspect of the present invention there is provided a filtering apparatus for a water recycling system, comprising: a filter; water storage means; means for enabling an upward flow of water through the filter into the water storage means; and jetting means positioned relative to the filter to direct at least one cleaning jet of water onto a surface of the filter, the water for the jetting means comprising water from the water storage means.

This apparatus prevents particles trapped in the filter or on the side of the filter opposite the jets from clogging the filter by the at least one jet of water dislodging the particles, so that they are flushed away. Consequently manual maintenance of the filter is kept to a minimum. Furthermore, the upward flow of water through the filter enables the height of the water storage means to be reduced compared with the height of the tall collection tank described in WO 97/02388.

The filter may form part of a fitting closely adjacent a surface of a pipe through which water enters the water storage means. The particles dislodged from the filter by the at least one jet may be flushed away by the water flowing in the pipe. As the fitting is close to the surface of the pipe, the water flowing past in the pipe is also closer to the filter so as to flush away the dislodged particles. Desirably, the pipe surface is the upper surface. The filter is preferably removable from the fitting for the purposes of filter maintenance. The fitting may comprise a threaded boss projecting from the pipe.

There may be a second pipe connected to the first pipe through which water enters the water storage means, the second pipe having an upwardly inclined portion downstream of the filter for providing a head of water to force water from the first pipe and through the filter for entry into the storage means. The first and second pipes may together form an integral pipe. There may be an overflow pipe from the storage means connected to a portion of pipe downstream of at least part of the upwardly inclined portion.

The filtering apparatus is desirably contained substantially within at least one unit remote from or at least adjacent to a building for which the water recycling system is adapted to recycle water, but may be positioned elsewhere such as in the basement of the building. The unit may be a sump tank. The water storage means may be in a unit remote from the at least one unit for the filtering apparatus.

Preferably, the apparatus includes pumping means for providing a pumped flow of water from the water storage means to a remote header tank. There may be pump control means for controlling the pump. There may be diverting means for diverting a portion of the pumped flow to the jetting means, the diverted portion comprising the. water for the jetting means.

The apparatus may have diverting means for diverting a further portion of the pumped flow to the water storage means. Means may be included for adding disinfectant to said further portion. The disinfectant adding means may include a container for receiving said further portion, said container adapted to contain dissolvable disinfectant material to add disinfectant to said portion by at least part of the material dissolving and entering solution, and said container having means for enabling resulting disinfectant solution to be received by the water storage means.

The invention may consist in a water recycling system comprising a filtering apparatus as described above, and including the remote header tank which is situated above the water storage means of the filtering system and connected to it by a supply pipe, the pump means arranged to pump water via the supply pipe from the water storage means to the header tank. The system may include the pump controlling means.

According to another aspect of the present invention there is provide a method of filtering water in a water recycling system, comprising the steps of: providing an upward flow of water through a filter into a water storage means; and directing at least one filter cleaning jet of water onto a surface of the filter, the jet water comprising water received from the water storage means.

According to a further aspect of the present invention there is provided a disinfecting apparatus for a water recycling system for a building, disinfectant apparatus being contained in a unit and comprising: water storage means; pumping means for providing a pumped flow of water from the water storage means to a remote header tank of the water recycling system; a container; diverting means for diverting a portion of the pumped flow to the container; means for adding disinfectant to the water in the container; and means for releasing disinfected water into the water storage means.

The disinfecting apparatus thus disinfects water within its water storage means. The water disinfected may be waste water received from, say, a bathroom and the disinfected water can be recycled. The unit is desirably remote from or at least adjacent to the building for which the water recycling system is adapted to recycle water, but may be positioned elsewhere such as in the basement of the building. The unit may be a sump tank. By disinfecting the water within the unit, it reduces the chance of the unit producing an unpleasant smell.

The invention may consist in a water recycling system comprising a disinfecting apparatus as described above, and including a remote header tank which is situated above the water storage means of the apparatus, the pumping means of the apparatus adapted to pump water from the water storage means to the header tank via a supply pipe.

According to yet another aspect of the present invention there is provided a method of disinfecting water in a water recycling system for building, comprising the steps of: providing a unit comprising water storage means and a container; directing water for recycling into the unit; pumping a flow of water from water storage means to a remote header tank of the water recycling system; diverting a portion of the pumped flow to the container; adding disinfectant to the water in the container; and releasing disinfected water into the water storage means.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic sectional view of a building showing a first embodiment of the invention;

Figure 2 is a schematic sectional view of a sump tank shown in Figure 1;

Figure 3 is a plan view of the tank shown in Figure 2;

Figure 4 shows a schematic sectional view of a disinfectant chamber in the tank;

Figure 5 is a schematic sectional view of a spray head above a filter on a pipe in the tank;

Figures 6 and 7 are views taken along lines 6-6 and lines 7-7, respectively, of Figure 5; and

Figure 8 is a schematic sectional view of a building showing a second embodiment of the invention. Referring to Figure 1 of the accompanying drawings, a system 1 is shown which is suitable for recycling waste or grey water. The system 1 includes a sump or collection tank 2 through which waste water from a building, such as the house 3 illustrated, flows, the sump tank being located outside the building. Waste water is piped from a bath 4 and a shower the sump tank 2 via a down pipe 6. The waste water down pipe 6 is vented to the atmosphere via a vent pipe 7. An outflow pipe 8 from the tank 2 connects the sump tank to an overflow 9 for a foul drain (not shown), the overflow also being connected to a trapped gulley 10.

The sump tank is also connected by a riser 11 to a break or header tank 12 in an elevated position, such as in the loft 13 of the house 3 shown. The header tank 12 is connected to the water mains supply 14, entry of supplementary mains water into the tank being controlled by a ball valve 15 when the supply of waste water is inadequate. There is also an over flow 16 from the tank. In addition, the header tank 12 is connected to toilets 17 by gravity downfeed piping 18 and the outflow from the toilets are connected to a foul drain (not shown) via a foul down pipe 20. The foul down pipe is also vented to the atmosphere. A capillary drain 21 connects the header tank to the vented part 22 of the foul down pipe 20 so that there is a slow and steady trickle of water from the tank 12 to prevent water remaining there too long.

The sump tank 2 has a pipe 23 for carrying waste water through the tank, the sump tank pipe 23 being connected to the waste water downpipe 6 by a connecting pipe 24.

Referring to Figures 2 and 3, the waste water pipe 23 in the sump tank 2 is shown with a portion 25 of the pipe protruding substantially horizontally from one side 26 of the sump tank. Immediately inside the sump tank, the sump tank pipe 23 bends substantially downwardly via a curved portion 27 before bending back to a substantially horizontal position via another curved portion 28. This substantially horizontal section 29 of pipe is the lowest portion of waste water piping leading to the foul drain overflow and this section 29 of pipe has a filter 30 in its top side. The horizontal section 29 has a portion 31 protruding beyond the opposite side 56 of the tank. The outflow pipe 8 is connected to this portion 31 and rises up to join the foul drain overflow. The sump tank 2 has an overflow pipe 32 extending from its side 56 which is above the protruding portion 31 of the horizontal section 29 of pipe. The overflow pipe 32 is connected to the outflow pipe 8 by a pipe 33 branching from a Y- shaped junction 34 in the outflow pipe 8. The pipes 8, 24, 33, 34 not forming part of the sump tank 2 are shown in dotted lines in Figures 2 and 3. All pipes protruding from the sides of the sump tank are mastically sealed to the sump tank.

The sump tank 2 has a pump 35 actuated by a control system including a float switch 36 (see Figure 1) in the header tank 12. The control system activates/ deactivates the pump 35 by means of a wire connection shown). The pump 35 also has an associated float switch 37 in the sump tank 2. The pump is connected by a pipe 38 (see also Figure 1) to the vertical riser 11 to the header tank, the portion 39 of the pipe 38 within the sump tank 2 having a non-return valve 40. The pipe portion 39 in the sump tank is connected to a disinfectant chamber 41 by a branch 42 from a first pipe junction 43 and is connected to a spray head 44 located above the filter 30 by a branch 45 from a second pipe junction 46. Both junctions 43, 46 are upstream of the non-return valve 40. The disinfectant chamber 41 is mounted in the sump tank 2 at a higher level than the spray head 44 and the branch 43 to the chamber 41 has a flow regulating valve 47.

Referring to Figure 4, the disinfectant chamber 41 contains disinfectant tablets 48 and overflow holes 49 above the tablets. The branch 42 to the chamber is connected to it above the overflow holes 49.

Referring to Figures 5 to 7, the spray head 44 is shown mounted above the filter 30. The spray head 44 has an end cap 50 containing a number of holes 51 through which water is sprayed. The filter 30 comprises a stainless steel mesh 52 centrally placed in the top of a screw cap 53 screwed onto a threaded boss 54 projecting from the top side of the substantially horizontal section 29 of the sump tank pipe.

All pipework in the sump tank 2 should preferably be of plastic material and all other pipework described should also preferably be of plastic material except for the mains supply 14.

A preferred arrangement has the following specification. The header tank 12 is 500 mm long, 400 mm wide and 600 mm high and weighs 75 kg when full. It is supplied with a 15 mm diameter mains supply 14 and is connected to a 32 mm diameter overflow 16 and a 15 mm diameter gravity downfeed 18. The sump tank 2 is 600 mm long, 450 mm wide and 800 mm high and it is connected to the header tank 12 by a 22 mm diameter riser 11 for a house or a 32 mm diameter riser 11 for a block of flats. The sump tank pipe 23 and overflow 32 have a diameter of 110 mm. The filter 30 comprises 75 micron stainless steel mesh filter -52 with a 90 mm clear diameter. The spray head 44 comprises a 32 mm (1 1/4 inch) diameter PNC pipe and the end cap 50 has nine 2.5 mm diameter holes 51 drilled through it.

In use, fresh water from the mains supply 14 enters the header tank 12 until the water level in the tank causes the ball 55 (see Figure 1) of the ball valve 15 to rise until the level in the header tank 12 reaches a mains cut-off level so that the ball valve 15 cuts off the supply of fresh water to the header tank.

Waste water from the bath 4 and/or shower 5 flows down the downpipe 6 and collects in the substantially horizontal section 29 of sump tank pipe 23. When this section of pipe 29 is filled with waste water, the rising, upwardly inclined, portion of the outflow pipe 8 provides a head of water which forces waste water from the substantially horizontal section 29 of pipe and through the filter 30 into the sump tank 2.

The water in the header tank 12 is used for refilling the cisterns of the toilets 17 after they have been flushed. When water in the header tank 12 has fallen to a pump cut-in level, the float switch 36 of the control system causes the pump 35 to be actuated so that waste water is pumped up the riser 11 and into the header tank 12. The float switch 37 in the sump tank 2 ensures that the pump 35 cannot operate unless there is sufficient water the sump tank. The pump 35 continues to operate until the water in the header tank 12 reaches a pump cut-off level which causes the header float switch 36 to deactivate the pump. Should an adequate supply of waste water not be received by the header tank 12 from the sump tank 2, the ball 55 of the ball valve 15 falls, permitting fresh water to enter the header tank 12 from the mains supply 14. Fresh water is supplied until the level in the header tank 12 reaches the mains cut-off level which is just below the pump cut-in level. At this point the ball 55 has risen to a level so as to cause the ball valve 15 to cut off the supply of fresh water to the header tank 12.

A proportion of the pumped waste water is diverted into disinfectant chamber 41 via the first branch 42 and junction 43. This water forms a disinfectant solution with the tablets 48 and when the chamber 41 has filled with enough water it overflows via the holes 49 into the sump tank 2 adding disinfectant to the waste water in the sump tank.

Another proportion of the pumped waste water is diverted through the spray head 44 via the second branch 45 and junction 46 and the spray head 44 sprays jets of waste water onto the filter mesh 52. The jets are sufficiently powerful to drive particles caught on the underside of the filter mesh 52 back into the substantially horizontal section of pipe 29 so that they can be carried out into the foul drain. Furthermore, once the pumped waste water contains disinfectant solution which has overflowed into the sump tank 2, the jets of water contain disinfectant to disinfect the filter 30.

Referring to Figure 8, a second system 60 is shown which is suitable for recycling rainwater. Where appropriate, like numerals have been used to designate like parts described above. The sump tank is replaced by a filter chamber 61, similar to the sump tank except where noted. The filter chamber 61 is connected to roof gullies 62 via rainwater pipes 63 and an outflow pipe 64 from the filter chamber is connected to a storm drain (not shown). The filter chamber 61 does not require a disinfectant chamber. The base of the filter chamber 61 is connected by a pipe 65 to a lower storage tank 66 which contains a pump 35 and float switch 37. The storage tank 66 has an access shaft 67 to the surface and also has an overflow 68 which is connected to outflow pipe 64 by a Y-shaped junction pipe 69. Similar to the embodiment, the filter chamber 61 has a pipe 32 above the protruding portion 31 of the horizontal section of pipe 29 and the pipe 32 is connected to the outflow pipe 64 by a branch 33 from a Y-shaped junction 34 where in the second embodiment the branch 33 acts as a grease trap.

The pump 35 in the storage tank 66 is connected by a pipe 70 to the vertical riser 11 to the header tank 12 with a section of the pipe 71 being within the filter chamber 61. This section of pipe 71 is connected to a head 44 located above the filter 30 by, a branch from a pipe junction.

Other parts of the embodiment shown in Figure 8 correspond to parts of the first embodiment and are accordingly not described again.

A preferred arrangement for the second embodiment has the same specification as the preferred arrangement for the first embodiment except where noted and where appropriate. The filter chamber 61 is 600 mm long, 450 mm wide and 550 mm high. The storage tank 66 has a storage capacity of between 1500 litres and 5000 litres. It has a diameter of 1250 mm and a length of between 1500 mm to 4500 mm depending upon its storage capacity.

In use, rainwater from the gullies 62 flows down the rainwater pipes 63 and collects in the substantially horizontal section 29 of pipe in the filter chamber 61. When this section of pipe 29 is filled with rain water, the rising, upwardly inclined, portion of the outflow pipe 8 downstream of the filter 30 provides a head of water which forces rain water from the substantially horizontal section 29 of pipe, through the filter 30 and into the filter chamber 61 where it drains out of its base and into the lower storage tank 66.

When water in the header tank 12 has fallen to the pump cut-in level, the pump 35 is actuated to pump rain water from the storage tank 66, up the riser 11 and into the header tank 12 from where it is used for flushing toilets 17. If an adequate supply of pumped rain water is not received by the header tank 12 from the storage tank 66, the ball valve 15 permits fresh water to enter the header tank from the mains supply 14.

A proportion of the pumped rain water is diverted through the spray head 44 in the filter chamber 61 which sprays jets of rain water onto the filter 30 to clear it.

Whilst particular embodiments have been described, it will be understood that various modifications may be made without departing from the scope of the invention.

For example, in one embodiment, the downward bend in the sump tank pipe 23 may be replaced by downward branch from a substantially horizontal pipe taking the waste water directly to a foul drain. This is arrangement is particularly useful in a system where the supply of waste water for recycling exceeds the demand for recycled water. The downward branch may contain a pre-filter to remove larger particles from the waste water before it enters the re-cycling system. Larger particles will remain on the top surface of the filter and be washed down the foul drain by the flow of waste water travelling directly to the foul drain.

In another embodiment, the disinfectant chamber 41 is positioned above the sump tank 2 and is connected to the vertical riser 11 between the sump tank 2 and the header tank 12. When the pump 35 operates, disinfectant is added to the water flowing up the vertical riser 11 to the header tank 12. When the pump stops, the disinfected water in the disinfectant chamber 41 falls by gravity back down the vertical riser 11. It is prevented from returning through the pump 35 by a non-return valve and so it passes out of the riser 11 through the spray head 44 to disinfect the filter 30. This advantageously results in a spray of water and disinfectant falling on the filter for some time after the pump 35 has been deactivated.

Claims

CLAIMS:

1. A filtering apparatus for a water recycling system 1 , the apparatus comprising: a filter 30; water storage means 2; and means for enabling an upward flow of water through the filter 30 into the water storage means 2.

2. An apparatus as claimed in claim 1, further comprising jetting means 44 positioned relative to the filter 30 to direct at least one cleaning jet of water onto a surface of the filter 30.

3. An apparatus as claimed in claim 2, wherein the water for the jetting means 44 comprises water from the water storage means 2.

4. An apparatus as claimed in any one of claims 1 to 3, wherein the means for enabling the upward flow of water comprises: a first pipe 23, through which water enters the apparatus, having a downwardly inclined portion upstream of the filter 30; and a second pipe 8, through which water leaves the apparatus, having an upwardly inclined portion downstream of the filter 30, wherein the filter 30 is positioned on the upper surface of a section of pipe 29 joining the first pipe and the second pipe.

5. An apparatus as claimed in claim 4, wherein the bottom surface of the filter 30 is positioned close to the top internal surface of the pipe 29.

6. An apparatus as claimed in any one of claims 1 to 5, further comprising means for adding disinfectant to said water storage means 2. 13

means for adding disinfectant to the water in the container 41; and means for releasing disinfected water into the water storage means 2.

13. A method of disinfecting water in a water recycling system 1 for building 3, comprising the steps of: providing a unit comprising water storage means 2 and a container 41; directing water for recycling into the unit; pumping a flow of water from water storage means 2 to a remote header tank 12 of the water recycling system 1; diverting a portion of the pumped flow to the container 41; adding disinfectant to the water in the container 41; and releasing disinfected water into the water storage means 2.