GB2360713A

GB2360713A - Runoff water filtration apparatus

Info

Publication number: GB2360713A
Application number: GB0107467A
Authority: GB
Inventors: Neil Macdonald; Robert A Aitken
Original assignee: Barr & Wray Ltd
Current assignee: Barr & Wray Ltd
Priority date: 2000-03-30
Filing date: 2001-03-26
Publication date: 2001-10-03
Anticipated expiration: 2021-03-26
Also published as: GB2360713B; GB0107467D0

Abstract

The apparatus has a housing that fits into an underground gulley and an outlet (3, figure 1) for communication with a water drainage pipeline. A filter 4 within the housing allows runoff water to pass through a central perforated column 6 via a funnel 5. The water passes radially through the perforations into a plurality of ring-shaped filtration media 7. Each filtration means 7 is retained by a plastic mesh and is separated from its neighbour by a spacer ring 8. A solids capture tray 9 is provided at the base of the filter. A removable lifting handle (10, figure 3) allows the filter to be removed for cleaning or replacement. The filter may be incorporated into a double sized gulley with the addition of a gulley pot for further catchment of entrained solids in storm water. The water is then routed to the filter via a transition pipe (17, figure 4) to minimise the risk of blockage of the filtering media.

Description

1 2360713 1 RUN-OFF WATER TREATMENT AND FILTRATION APPARATUS 2

3 The present invention relates to a wastewater filtration 4 system. More particularly the present invention relates 5 to a retrievable filter for use with underground storm 6 water drainage systems. 7 8 In this specification references to the word ""filtration" 9 should be construed broadly. For example, the word, 10 unless context otherwise dictates, should be interpreted 11 as including water treatment generally, absorption, 12 adsorption and bioremediation. 13 14 Storm water drainage systems are employed in areas where 15 the development of buildings and roadways remove the 16 natural absorbing action of soil and plants and encourage 17 water run-off. Typically said storm water drainage 18 systems include a plurality of storm drains, usually 19 provided at selected intervals along the edges and 20 curbsides of roads, car parks, and similar water 21 catchment areas, into which surface water run-off is 22 channelled. Upon entering a storm drain, the run-off 23 water passes into a collection gulley that, in turn opens 24 into one or more water drainage pipelines which

2 1 eventually discharge the wastewater into watercourses and 2 rivers.

3 4 In recent years there has been growing concern regarding the condition of water entering waterways and lakes.

6 Storm water run-off can contain silt, sediment, solid 7 materials and both domestic and industrial contaminants.

8 There is also a particular concern about the level of 9 hydrocarbons and other pollutants, which are generated by motor vehicles and can enter waterways via storm drainage 11 systems.

12 13 It has become more common for Governments and 14 Environmental Protection Agencies to impose stringent requirements and regulations on developers to ensure that 16 any waste or storm water discharged into waterways is as 17 clean and free from contaminants as possible. As a 18 result there have been numerous attempts to produce 19 devices which remove contaminants such as hydrocarbons, metals and industrial wastes from stormwater before it is 21 discharged. Some of the simplest attempts have involved 22 using filters at ground level on the outer surface of the 23 storm drain to prevent large and solid material from 24 entering the storm water drainage system. Whilst these prevent debris and litter from contaminating the run off 26 which is eventually released into waterways, ground level 27 filters do not remove absorbed fluid pollutants which may 28 include hydrocarbons and other chemicals such as 29 pesticides and insecticides.

31 An attempt to overcome this problem has been made in US 32 Patent No 5820 762 which teaches of a filter insert for 33 use within a storm drain. The filter insert has an open 34 top and bottom end and is comprised of a vertical 3 1 arrangement of mesh bags containing filter media which 2 sit on filter plates within a support frame which is hung 3 from a shoulder cast. Run off passes into the open top 4 end of the apparatus, and through each of the bags in series and out of the open bottom end. In a particular 6 embodiment taught in this Application the filter insert 7 has a settling chamber which is connected to the vertical 8 series of mesh bags by a spillway through which water can 9 flow when the settling chamber becomes full. This apparatus presents a number of problems. Most notably, 11 because the filter bags are in a vertical series, it is 12 necessary for the spillway which transports water from 13 the settling chamber into the filtering chamber to be 14 located at the upper end of the chambers such that the water can pass vertically down through the series of 16 filters when it passes into the filtering chamber. Thus, 17 it is necessary for the settling chamber to be filled to 18 almost capacity before the run off can pass through the 19 spillway into the filtering means. This encourages the risk of flooding. For example it will be appreciated 21 that if the settling chamber is almost full when a high 22 volume of run off suddenly enters a storm drain, for 23 example during a thunderstorm, then the spillway will not 24 be able to remove water into the filtering chamber at a sufficient rate to prevent the settling chamber from 26 overflowing, due to the close proximity of the spillway 27 to the storm drain which opens to the surface. The speed 28 which the run-off can enter the collection gulley through 29 the storm drain is also compromised by the lid of the apparatus which closes over the filtration chamber so as 31 to channel the run-off through vents which are positioned 32 in the lid above the settling chamber. This reduces the 33 area of the collection gulley through which the run-off 34 entering the storm drain can pass.

4 2 It will also be appreciated that run-off water which 3 passes into the storm drain is often at very high speed 4 and in US Patent No 5820762 will immediately pass into the filtration bags. There is therefore a risk that the 6 mesh bags which sit freely within the support frame will 7 be disrupted or even torn as the water which passes into 8 the filtration chamber is at high speed and is turbulent.

9 If disrupted, water may pass peripherally to the filter bags, and as a result any contaminants within the run-off 11 may not be properly filtered out. It is also recognised 12 that the first upper bag in the vertical series will 13 become spent more rapidly than the bags further down the 14 series. Furthermore, as the water must pass through the bags in succession, the absorbent effectiveness of the 16 upper bag may become compromised at times of high run 17 off, due to waterlogging. Accordingly, the speed of the 18 passage of water through the subsequent series of filters 19 will be compromised.

21 In addition it is recognised in the present invention 22 that a particular disadvantage of the filtering means of 23 US Patent No 5820762 lies in the fact that the filtering 24 bags are arranged in a series. In the event of blockage 25 of one of the bags in the series, the entire flow path of 26 the runoff water into the apparatus will be interrupted. 27 28 It would therefore be advantageous to provide a filter 29 for use in a storm drain collection gulley which efficiently removes contaminants from run-off water but 31 is adapted such that there is a minimal risk of flooding 32 or disruption to the filter media by turbulent or high 33 flowing water. Furthermore it would be an advantage to 34 provide a filter in which the speed at which run-off 1 water enters the filter media is reduced thereby 2 increasing the time the water is exposed to the filter 3 media. It would also be an advantage to provide a filter 4 which can be adapted for use in both single and double sized collection gulleys.

6 7 It is an object of the present invention to provide means 8 for removing contaminants such as hydrocarbons and 9 chemicals from the storm water run-off, which passes into storm water drainage systems in order to prevent and 11 minimise pollution of the waterways into which the storm 12 water run-off is discharged.

13 14 It is a further object of the present invention to provide filtration apparatus for removing contaminants 16 such as hydrocarbons and other chemicals from run-off, 17 which can be readily and retrievably inserted into a 18 collection gulley of a storm water drainage system.

19 It is a yet further object of the present invention to 21 provide filtration apparatus for removing contaminants 22 from run-off, wherein the filtering means of the 23 apparatus will not be destroyed or disrupted by turbulent 24 or fast flowing water and wherein the exposure time of the run-off water to the filtration media is increased.

26 27 It is a further object of the present invention to 28 provide filtration apparatus for removing contaminants 29 from run-off, wherein blockage of any one of the filtering means of the apparatus will not interrupt the 31 functioning of the other filtering means.

32 33 According to the present invention there is provided 34 apparatus for removing contaminants from run-off water; 6 1 the apparatus comprising a filtration unit which can be 2 retrievably inserted into a collection gulley, wherein 3 said unit is comprised of a plurality of filtration 4 means, said filtration unit being characterised in that run-off water can flow through each of the filtration 6 means in parallel to each of the other filtration means.

7 8 In one embodiment of the present invention the housing 9 contains a distributing column, around which the plurality of filtration means sit.

11 12 Preferably each of the filtration means is afforded a 13 ring shape.

14 Preferably the distributing column has a number of radial 16 outlets.

17 18 Preferably the radial outlets are perforations.

19 Preferably the distributing column is provided with by 21 pass means for allowing water to bypass the plurality of 22 filtration means at times of high run-off.

23 24 Preferably the by pass means are overflow openings.

26 Preferably the perforated distributing column slows the 27 passage of run-off water into the filtration means.

28 29 Preferably the plurality of filtration means are filtration media contained within a media retaining mesh.

31 32 Preferably the retaining mesh is made of a plastic 33 material.

34 7 1 Most preferably the mesh is made of polypropylene.

2 3 Preferably each of the filtration means sits on a spacer 4 ring.

6 Preferably the size of the filtration media is selected 7 to suit the contaminant which is to be filtered.

8 9 Preferably the distributing column has lifting means to allow the filter to be retrieved from the collection 11 gulley.

12 13 Preferably said lifting means is a handle which can be 14 engaged by a lifting hook.

16 Preferably a funnelling means is provided at the upper 17 end of the distributing column.

18 19 Preferably the apparatus has a solids catching means.

21 Most preferably said solids catching means is a tray 22 located at the base of the apparatus.

23 24 Preferably the apparatus has means for communicating with a water drainage pipeline.

26 27 In an embodiment of the present invention the apparatus 28 comprises catchment means for removing solids from the 29 run-off water.

31 Preferably said catchment means is a chamber into which 32 the run-off water is introduced, said catchment means 33 being characterised in that the run-off water can pass 8 1 continuously from the catchment means into the plurality 2 of filtering means.

3 4 Optionally the catchment chamber and plurality of filtering means are contained within individual and 6 separate housings.

7 8 Preferably the housing which contains the catchment 9 chamber has an outlet which communicates with the housing 10 which contains the filtering means.

11 12 Preferably the outlet is in the form of a transition pipe 13 which allows the flow of water from the first housing to 14 the second.

16 Alternatively the catchment chamber and filtration means 17 are contained within one housing and share a common wall.

18 19 When the catchment chamber and filtration means are contained within one housing, preferably each of said 21 filtration means is afforded a semi-circular shape.

22 23 Preferably the shared common wall has a plurality of 24 apertures to allow passage of run-off water from the catchment chamber into the filtering means.

26 27 Preferably the apparatus comprises means for channelling 28 run-off water into the catchment chamber.

29 Most preferably said channelling means is a deflector 31 plate and is biased such that run-off water is directed 32 into the catchment chamber.

33 9 1 In order to provide a better understanding of the present 2 invention, embodiments will now be described by way of 3 example only with reference to the accompanying figures 4 in which:

6 Figure 1 illustrates a single run-off water filtering 7 apparatus for use in a single sized collection gulley, in 8 accordance with the present invention; 9 Figures 2 and 3 are cross sectional views of the run-off 11 water filtering apparatus of Figure 1; 12 13 Figure 4 illustrates an alternative embodiment of the 14 run-off water filtering apparatus, for use in a double sized collection gulley; 16 17 Figures 5, illustrates a further alternative embodiment 18 of the filtering apparatus in cross section, for use in a 19 single sized collection gulley and; 21 Figures 6 and 7 illustrate the embodiment of Figure 5 in 22 cross sectional detail.

23 24 Referring firstly to Figure 1, filtering apparatus is generally illustrated at 1. The apparatus is comprised 26 of a housing 2, typically made of a plastics material, 27 which fits into a single size underground gulley (not 28 shown), and an outlet 3 which communicates with a water 29 drainage pipeline. The housing 2 contains a filtering device, generally depicted at 4 in Figures 2 and 3 for 31 filtering surface water run off which passes into the 32 apparatus 1 through a storm drain (not shown).

33 1 Turning now to Figures 2 and 3 the filtering device 4 is 2 comprised of a gulley funnel 5 which funnels the run off 3 entering the storm drain a central perforated column 6 of 4 the filtering device 4. The perforated column 6 is encircled by a plurality of filtration means 7. The 6 filtration means 7 can be chosen to suit the content of 7 the water to be filtered, for example it may be 8 cellulose, charcoal or any other suitable material. The 9 filtration means 7 are retained within a plastic mesh and are afforded a ring shape such that each media retaining 11 mesh 7 circles around the circumference of the perforated 12 column 6. Each filtration means 7 sits upon, and is 13 separated from its neighbouring filtration means by a 14 spacer ring 8. The filtering device 4 also comprises a solids capture tray 9 which acts to capture any solid 16 matter which is filtered out of the run-off and settles 17 at the bottom of the filtering device 4. The complete 18 filtering apparatus 1 is sized so as to fit into a single 19 sized collection gulley (not shown). It will be appreciated that at some point of time it may be 21 necessary to retrieve the filtering apparatus 1, for 22 example to clean the apparatus or to change the 23 filtration media 7. The central column therefore has a 24 removable lifting handle 10, which can be engaged on a lifting hook of a crane, or similar vehicle mounted 26 device. The gulley funnel 5 can be easily removed from 27 the upper end of the central column 6 and the handle 10 28 can be readily attached to the central column 6 to allow 29 retrieval of the apparatus when desired.

31 The filtering apparatus of Figure 1 to 3 filters runoff 32 water contaminated from, for example, the road or car 33 park surface. Run-off is channelled into storm drains 34 typically located at selected intervals along the 1 curbside or edge of the road. The run-off passes 2 underground through the storm drain into the gulley 3 funnel 5 of the apparatus 1, which sits under the storm 4 drain in the collection gulley. The run-off flows down 5 the perforated central column 6 and passes radially 6 through the perforations in the central column 6 into the 7 filtration media 7 which encircles the central column 6. 8 It will be appreciated that by initially passing through 9 the central column 6, the flow of water into the 10 filtration media 7 is slowed. This minimises the risk of 11 disruption or damage to the media and increases the 12 efficiency of the filtering process. 13 14 The filtration media 7 which encircles the central column 15 6 is manufactured from an absorbent porous material which 16 removes absorbed fluid contaminants such as hydrocarbons, 17 oil and chemicals from the run-off, but allows water to 18 pass. The type and size of porous filtration media used, 19 and also the size of opening in the media retaining mesh, 20 can be chosen to suit the contaminant, and acts not only 21 as a filter, but also a bio system to digest oil. 22 Furthermore, as a plurality of filtration media 7 are 23 incorporated into the apparatus 1, a number of different 24 media may be used, wherein each type of media absorbs and 25 removes a particular contaminant. 26 27 In normal conditions, the run-off will collect in the 28 gulley pot where the treatment media 7 will remove 29 contaminants before allowing the 'clean' water to pass 30 through the outlet 2 into the water drainage pipeline 31 (not shown). However, in the event of high flow rates, 32 which may occur in times of thunderstorms, any delay to 33 the passage of water through the storm drainage system 34 can result in flooding of the ground surface where the 12 1 storm drains of the system are located. In the present 2 invention, the water which enters the apparatus is, in 3 effect, "clean' rainwater and can by pass the filtration 4 system 4 by virtue of the overflow by pass opening 11 near the upper end of the apparatus.

6 7 Figure 4 shows an alternative embodiment of a storm drain 8 filter apparatus at 12, adapted for use in a double sized 9 gulley 13. The filtering apparatus 12 takes the form of a double pot device and is specifically adapted for 11 applications where entrained solids are problematic and 12 can block the storm run-off filtration system. The 13 apparatus 12 comprises a first gulley pot 14 which acts 14 as a solids catchment device, and a second gulley pot 15 which contains a filtration apparatus 16 as described in 16 Figures 1, 2 and 3. The first gulley pot 14 is located 17 below a storm drain 16 and collects the surface water 18 run-off which flows into the drain 16. Solids such as 19 silt, sediment and debris settle to the bottom of the first gulley pot 14 to form a sludge slump 16. The first 21 14 and second 15 pots are connected by a transition pipe 22 17 which allows the run-off, free from solids, to pass 23 into the second pot 15 and through the filtration device 24 18 as described for Figures 1 - 3.

26 The apparatus illustrated in Figure 4 allows solid 27 material to be removed from the run-off before it is 28 passed through the filtering media 19 and therefore 29 minimises the risk of the filtering media 19 becoming blocked. The central perforated column 20 of the 31 filtration device 18 is provide with overflow bypass 32 means 21 which allows excess water to bypass the 33 filtering system in times of high speed run-off, and also 34 a solids capture tray 22 for collecting any small solid 13 1 matter which may not have been removed in the first 2 settling chamber 14. The above described apparatus has 3 advantages over the prior art in that speed and 4 turbulence of the run- off water passing into the filtering means is reduced by an initial passage through 6 a perforated central column 20. The run-off does not 7 therefore "rush' into the filter media 19, minimising the 8 risk of disruption or saturation of the media 19.

9 Although the described filtering device of Figure 4 is 11 effective in removing solids from run-off water before it 12 enters the filtering device 18, it is a double pot 13 configuration and can therefore not be used in a single 14 sized collection gulley. Figure 5 shows a further embodiment of the present invention, wherein a filtering 16 apparatus is suitable for separating solids from run-off 17 water before it is filtered, but is also suitable for use 18 in a single sized collection gulley.

19 The filtering apparatus 23 is comprised of a housing 24 21 which fits into a single size underground gulley (not 22 shown), and an outlet 25 which communicates with a water 23 drainage pipeline, similar to the apparatus of Figure 1.

24 However it can be seen from the longitudinal cross 25 sections of Figures 6 and 7 that the apparatus in fact, 26 has a combi-pot configuration. The combi-pot is 27 comprised of a first chamber 26 which allows the solid 28 material contained in run-off water to settle before 29 entering a second filtering chamber 27 which contains a plurality of filtering media 28, each being afforded a 31 semicircular shape and being retained in a plastic mesh, 32 the plurality of media being arranged in a stack. Each 33 of the filtration media meshes sits upon a spacer ring 34 29. Run-off water entering the storm drain (not shown) 14 1 under which the apparatus 23 sits, is directed into the 2 first chamber 26 by a deflector plate 30, which is 3 located substantially above the filtering chamber 27 and 4 is biased in the direction of the settling chamber 26.

The apparatus also comprises a solids settling tray 31, 6 overflow opening 32 and a lifting hook 33 for retrieving 7 the apparatus 23.

8 9 The advantage of the apparatus shown in Figures 5 to 7 over the prior art, lies in the fact that the run-off

11 water is free to flow into the filtration media 28 in the 12 second chamber 27 at any time, via the plurality of 13 aperture 34 contained in the central dividing grid or 14 column 35 between the two chambers. It is therefore recognised that there is a minimal risk of the first 16 settling chamber 26 from become full of run-off and 17 flooding back through the storm drain. In addition the 18 filtration media 28 are tightly packed in a mesh rope and 19 separated by spacer rings 29 which thereby minimises the risk of disruption or damage to the media by turbulent or 21 rapid flowing water.

22 23 A further advantage of the present invention is that 24 blockage of one of the filtering means contained in the apparatus will not detrimentally affect the filtering 26 function of the apparatus. This is because the run-off 27 water which enters the apparatus can flow through each of 28 the filtering means in parallel, that is at the same time 29 as it flows through the other filtering means in the apparatus.

31 32 Further modifications and improvements may be 33 incorporated without departing from the scope of the 34 invention herein intended.

Claims

1 Claims:

2 3 1. Apparatus for removing contaminants from run-off 4 water; the apparatus comprising a filtration unit which can be retrievably inserted into a collection 6 gulley, wherein said unit is comprised of a 7 plurality of filtration means, said filtration unit 8 being characterised in that run-off water can flow 9 through each of the filtration means in parallel to each of the other filtration means.

11 12

2. Apparatus as claimed in Claim 1, wherein the housing 13 contains a distributing column, around which the 14 plurality of filtration means sit.

16

3. Apparatus as claimed in Claim 2, wherein each of the 17 filtration means is afforded a ring shape.

18 19

4. Apparatus as claimed in Claim 2 or Claim 3, wherein the distributing column has a plurality of radial 21 outlets.

22 23

5. Apparatus as claimed in Claim 4, wherein the radial 24 outlets are perforations.

26

6. Apparatus as claimed in any one of the Claims 2 to 27 5, wherein the distributing column is provided with 28 by pass means for allowing water to bypass the 29 plurality of filtration means at times of high run off.

31 32

7. Apparatus as claimed in Claim 6, wherein the by pass 33 means are overflow openings.

34 16 1

8. Apparatus as claimed in any one of the Claims 2 to 2 7, wherein the distributing column slows the passage 3 of runoff water into the filtration means.

4

9. Apparatus as claimed in any one of the preceding 6 Claims, wherein at least some of the plurality of 7 filtration means are filtration media contained 8 within a media retaining mesh.

9

10. Apparatus as claimed in Claim 9, wherein the 11 retaining mesh is made of a plastic material.

12 13

11. Apparatus as claimed in any one of the preceding 14 Claims, wherein the filtration means sit on respective spacer rings.

16 17

12. Apparatus as claimed in any one of Claims 2 to 11, 18 wherein the distributing column has lifting means to 19 allow the filter to be retrieved from the collection gulley.

21 22

13. Apparatus as claimed in Claim 12, wherein said 23 lifting means is a handle which can be engaged by a 24 lifting hook.

26

14. Apparatus as claimed in any one of Claims 2 to 13, 27 wherein a funnelling means is provided at the upper 28 end of the distributing column.

29

15. Apparatus as claimed in any one of the preceding 31 Claims, wherein the apparatus has a solids catching 32 means.

33 17 1

16. Apparatus as claimed in Claim 15, wherein said 2 solids catching means is a tray located at the base 3 of the apparatus.

4

17. Apparatus as claimed in any one of the preceding 6 Claims, the apparatus further having means for 7 communicating with a water drainage pipeline.

8 9

18. Apparatus as claimed in Claim 15, wherein said solids catchment means is a chamber into which the 11 run-off water is introduced, said catchment means 12 being characterised in that the run-off water can 13 pass continuously from the catchment means into the 14 plurality of the filtering means.

16

19. Apparatus as claimed in Claim 18, wherein the 17 catchment chamber and plurality of filtering means 18 are contained within individual and separate 19 housings.

21

20. Apparatus as claimed in Claim 19, wherein the 22 housing which contains the catchment chamber has an 23 outlet which communicates with the housing which 24 contains the filtering means.

26

21. Apparatus as claimed in Claim 20, wherein the outlet 27 is in the form of a transition pipe which allows the 28 flow of water from the first housing to the second.

29

22. Apparatus as claimed in Claim 18, wherein the 31 catchment chamber and filtration means are contained 32 within one housing and share a common wall.

33 18 1

23. Apparatus as claimed in Claim 22 or 23, wherein each 2 of said filtration means is afforded a semi-circular 3 shape.

4

24. Apparatus as claimed in Claim 22 or 23, wherein the 6 shared common wall has a plurality of apertures to 7 allow passage of run-off water from the catchment 8 chamber into the filtering means.

9

25. Apparatus as claimed in Claim 24, wherein the 11 apparatus comprises means for channelling run-off 12 water into the catchment chamber.

13 14

26. Apparatus as claimed in claim 25, wherein said channelling means is a deflector plate and is biased 16 such that run-off water is directed into the 17 catchment chamber.