EP4441301A1

EP4441301A1 - Storm water filtration system

Info

Publication number: EP4441301A1
Application number: EP22830434.1A
Authority: EP
Inventors: Jack Elisabeth Marie THEUNISSEN; Dave M. J. SEVRIENS
Original assignee: Rockwool AS
Current assignee: Rockwool AS
Priority date: 2021-12-03
Filing date: 2022-12-02
Publication date: 2024-10-09
Also published as: WO2023099768A1; CA3239773A1

Abstract

The invention relates to a storm water filtration system comprising: (i) a storm water drain pit (12); (ii) a filtering well (1) for filtering storm water; (iii) a storm water collection system (7) for storing filtered storm water; wherein the filtering well comprises; an inlet (2) for storm water to enter the filtering well; wherein the inlet (2) is in fluid communication with the storm water drain pit; an outlet (3) for filtered storm water to exit the filtering well; wherein the outlet (3) is in fluid communication with the storm water collection system (7); a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3). The invention also relates to a method of filtering and storing storm water using a storm water filtration system as described herein and a method of installing a storm water filtration system as described herein.

Description

STORM WATER FILTRATION SYSTEM

Field of the invention

The invention relates to a storm water filtration system comprising a filtering well comprising a filter comprising man-made vitreous fibres (MMVF), a storm water drain pit and a storm water collection system, particularly wherein the storm water collection system is an infiltration system.

Background of the invention

Storm water (e.g. rain, snow, sleet, hail and water run-off from residential and commercial areas) is collected and transported by storm water drain systems. Typically, the storm water is channelled into the storm water system via storm water drain pits i.e. storm water drains in the ground, also called storm water gullies, wells, catch basins or storm water inlets. Storm water drain systems typically have a number of storm water drain pits, which lead to a network of underground drain pipes. The storm water is collected by the storm water drain pits, filtered to remove particulates or debris and then transported to a desired location.

In times of high precipitation, storm water drainage systems may become overwhelmed leading to flooding and waterlogging of the ground. In order to combat this, storm water collection areas, such as water infiltration systems, are installed. These are designed to store large volumes of excess water. The water can subsequently be transported to water collection points and/or allowed to dissipate into the surrounding ground once it is dry enough and/or used at a later stage (for example, to water plants). In this way, storm water collection systems can prevent flooding by storing storm water until such a time as it is convenient to use or dispose of the water. For example, WO 2013/072082 A1 discloses a water drain reservoir comprising a coherent man-made vitreous fibres (MMVF) substrate and a conduit having two open ends.

Typically the process of installing storm water drainage and storm water collection systems into the ground is very disruptive. It can result in entire streets being excavated which is time-consuming and disruptive to the residents of the area. Often municipalities wait until there are multiple reasons to excavate a street (for example to address other piping or cables underground) before installing water infiltration systems. It would therefore be desirable to provide a water drainage and storm water collection system that can be used to prevent localised flooding, and installed with minimal disruption to the surrounding area.

Furthermore, it is desirable to collect the particulates, pollutants and debris at the initial point of entry into the storm water drain system i.e. in the storm water drain pit. This is because it is necessary for the particulates, pollutants and debris, which build up, to be removed periodically from the drain system in order to prevent blockage of the drainage and filtering system. Typically, in order for the collection of particulates, pollutants and debris to be removed, it is necessary for an individual (e.g. a maintenance worker) to first remove the filter. This can be time-consuming as the storm water drain pit must be, in part, dismantled and then rebuilt. US 2009/0277820 A1 discloses a filtering device for storm water run-off. It contains a removable frame and a filtering component, which may be made from fiberglass.

Alternatively, the filter may remain in the storm water drain pit while cleaning occurs. For example, WO2021/028526 A1 discloses a storm water drain pit with a cylindrical filter. The storm water drain pit cleaning tube can be inserted inside the hollow centre of the filter. However, as the cleaning process is very aggressive, this can sometimes lead to the filter being damaged. It would therefore be desirable to provide a water drainage system and storm water collection system in which the storm water drain pits can be regularly cleaned without removing or damaging the filter.

NL1010476 relates to a gully or drain pit for taking care of rapid discharge of rainwater to a sewerage system. The gully consists generally of a vortex chamber having a lid provided with openings through which rain water flows into the vortex chamber. The vortex chamber is provided with an outlet (swirling discharge) connected to the sewer. A filter element (sieve) is positioned in, and over the entire height of, the vortex chamber. The filter element is preferably made of plastic. This system is disadvantageous because it can only capture very coarse particles: small particles can pass through the filter unobstructed.

EP3674493 discloses a gully having a sewer outlet configured to couple the gulley to a sewer system. The gully further comprises at least one infiltration outlet being configured to transfer liquid in the gully to the ground around the gulley. A filter element may be positioned in the gully infiltration outlets and is made from concrete. This filter is cleaned by using a pressure washer and/or a vacuum cleaner. As discussed above, this aggressive form of cleaning can result in damage to filters and might push the debris further into the pores of the filter, such that the functionality of the filter does not fully recover to its original capacity.

DE10348520 relates to a filter system for water loaded with metal ions, the filter system having an inlet, an inlet chamber, a coarse filter (i.e. leaf catcher), a raw water chamber, a filter chamber containing a filter substrate, a pure water chamber and a rain water outlet. The filter substrate preferably comprises zeolite. A buffer can be positioned in connection with the filter system - in the event of heavy rain, water can be stored in the buffer before being filtered in the filter chamber. The buffer is covered with water-impermeable covering to prevent this stored water entering the ground. WO 2021/130106 A1 discloses storm water management system comprising a first conduit, a storage device, a first well and a valve, wherein the storage device comprises a coherent man-made vitreous fibre module (MMVF module), wherein the MMVF module comprises an upper passage and a lower passage, wherein the upper passage is in fluid communication with the first conduit, and wherein the lower passage is connected to the first well by the valve. The disadvantage with this system is that it can only capture very coarse particles: small particles can pass into the storage device unobstructed.

It would be desirable to produce a storm water drainage, filtration and storage system in which the filter does not need to be removed or will not be damaged when the storm water drain pit is cleaned. It would be desirable to produce a system that can be installed in the ground quickly and flexibly, minimising disruption, while also reducing the area of the street/ground that has to be excavated. It would be desirable to produce a system in which filtered storm water can be stored locally, and used on site (for example to water nearby plants) or transferred to the surrounding ground (i.e. an infiltration system). It would be desirable to produce a filter for a storm water drain pit system which has equivalent or improved filtration in comparison to existing filtering systems i.e. can remove the same or more pollutants, contaminants, particulates and debris, while also being less likely to get clogged or blocked. Furthermore, it would be desirable to produce a filter system for a storm water drain pit which is environmentally acceptable and economical in terms of production, installation and use. It would be advantageous to have a system in which the storm water collection system, especially an infiltration system, is protected from pollutants, contaminants, particulates and debris so that it does not need to be periodically dug up and replaced or cleaned. This is particularly the case when the storm water filtration system is located in an urban or industrial area were rainwater can be contaminated with man-made material that should be prevented from entering the ground or waterways for environmental reasons. The present invention solves these problems.

Summary of the invention According to a first aspect of the invention, there is provided a storm water filtration system comprising:

(i) a storm water drain pit (12);

(ii) a filtering well (1 ) for filtering storm water;

(iii) a storm water collection system (7) for storing filtered storm water; wherein the filtering well comprises; an inlet (2) for storm water to enter the filtering well; wherein the inlet (2) is in fluid communication with the storm water drain pit; an outlet (3) for filtered storm water to exit the filtering well; wherein the outlet (3) is in fluid communication with the storm water collection system (7); a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3).

According to a second aspect of the invention, there is provided a method of filtering and storing storm water comprising the steps of:

- providing a storm water filtration system as described above and herein;

- allowing storm water to enter the storm water drain pit for coarse filtration;

- allowing water to flow from the storm water drain pit into the inlet chamber (5) of the filtering well (1 ) via the inlet (2);

- allowing the storm water to pass from the inlet chamber (5) to the outlet chamber (6) through the filter (4);

- allowing the filtered storm water to exit the filtering well via the outlet (3) into the storm water collection system (7) for storage.

According to a third aspect of the invention, there is provided a method of installing a storm water filtration system, comprising the steps of;

- identifying a storm water drain pit in the ground or positioning a storm water drain pit in the ground; - positioning a filtering well in the ground, wherein the filtering well comprises; an inlet (2) for storm water to enter the filtering well; wherein the inlet (2) is in fluid communication with the storm water drain pit; an outlet (3) for filtered storm water to exit the filtering well; a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3);

- positioning a storm water collection system in ground, wherein the outlet (3) of the filtering well is in fluid communication with the storm water collection system (7).

The inventors discovered that a storm water drain system according to the present invention solves the above described problems.

The filtering well can be connected to a standard storm water drain pit, already present in the ground. Storm water therefore enters the standard storm water drain pit which preferably comprises a sand trap and a leaf catcher. Coarse filtration of e.g. leaves, twigs and sand occurs and the water is then directed into the filtering well, where finer filtration occurs through the MMVF filter. Once the water is filtered through the MMVF filter, it can then be directed to a storm water collection system for storage and later use, or infiltration into the surrounding ground. By decoupling the filtering well from the standard storm water drain pit, this means the filtering well does not need to be cleaned regularly. Instead, the storm water drain pit is cleaned in the usual manner (e.g. twice a year with aggressive methods such as vacuum cleaning) and there is no danger of the MMVF filter being damaged or any need for the MMVF filter to be removed. This simplifies maintenance considerably which is highly desirable for local councils/municipalities. Furthermore, the system of the present invention can prevent flooding and can store water for later use or disposal based on infrastructure already in place (i.e. the standard storm water drain pit) with minimal disruption to the surrounding ground during installation. The system is flexible and decentralised, which means it can be installed at specific sites, for example around one standard storm water drain pit, rather than requiring an entire street to be excavated. The system can be installed under existing roads or pavements, again minimising disruption during installation.

In one embodiment, the filtering well has the combined purpose of filtration of storm water and ventilation of a storm water collection system. Storm water enters the filtering well, is filtered, and exits via an outlet to a storm water collection system. Air displaced from the storm water collection system, as the filtered water enters, passes into the filtering well. This allows for the storm water collection system to fill quickly with water at times of heavy rainfall. It also maximises use of the storm water collection system by allowing the air to escape and water to take its place. Furthermore, it also reduces the disruption caused by installing water drainage and storm water collection systems in the ground, by combining two functions in one well.

Brief description of the figures

Figure 1 shows a side view of a storm water filtration system according to an embodiment of the invention.

Figure 2 shows a top view of a storm water filtration system according to an embodiment of the invention.

Figure 3 shows a filtering well for use in the invention.

Figure 4 shows a filtering well and a storm water collection system for use in the invention.

Figure 5 shows a storm water filtration system according to an embodiment of the invention comprising:a storm water drain pit, a filtering well and a storm water collection system.

Figure 6 shows a top view of a filtering well for use in the invention. Figure 7 shows a filter for use in the invention, comprising a frame and guide.

Detailed description of the figures

Figure 1 shows a side view of a storm water filtration system according to an embodiment of the invention. Figure 1 shows a storm water filtration system comprising a storm water drain pit (12); a filtering well (1 ) and a storm water collection system (7). In this embodiment, the storm water filtration system is located underground with the top surface of the storm water drain pit and the top surface of the filtering well at ground level. In use, water enters the storm water drain pit via an inlet in the top surface. The storm water is coarsely filtered to remove leaves, twigs and other large debris and channelled into the filtering well (1 ) via an inlet (2). The storm water then moves from the inlet chamber, through the filter, into the outlet chamber. The filtered water then exits the filtering well via the outlet (3) into the storm water collection system (7). The storm water collection system (7) is capable of storing a high volume of filtered water, and is preferably able to dissipate it into the surrounding ground (i.e. when acting as an infiltration system). As filtered water flows into the storm water collection system (7), air may leave via the air vent (8) into the filtering well. Figure 2 shows the embodiment of Figure 1 from a top perspective.

Figure 3 shows a filtering well for use in an embodiment of the invention. Storm water enters the filtering well (1 ) via the inlet (2). The filtering well (1 ) comprises a filter (4) which is held in a frame (9) and divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6). Storm water passes through the filter (4) from the inlet chamber (5) to the outlet chamber (6) and then exits via the outlet (3). The filtering well (1 ) has a lid (11 ) which comprises a perforation (13). Air entering the filtering well (1 ) via the air vent (8) can pass out of the filtering well (1 ) via the perforation (13).

Figure 4 shows the filtering well (1 ) described above for Figure 3 in combination with a storm water collection system (7) for use in an embodiment of the invention. Filtered storm water flows from the outlet (3) into the storm water collection system while air from the storm water collection system (7) passes via the air vent (8) into the filtering well (1 ).

Figure 5 shows the filtering well (1 ) and storm water collection system (7) of Figure 4 in combination with a storm water drain pit (12). Water enters the storm water drain pit (12) via an inlet in the top surface. The storm water is coarsely filtered and then channelled into the filtering well (1 ) via an inlet (2). The storm water then moves from the inlet chamber (5), through the filter (4), into the outlet chamber (6). The filtered water then exits the filtering well (1 ) via the outlet (3) in to the storm water collection system (7). As filtered water flows into the storm water collection system (7), air leaves via the air vent (8) into the filtering well (1 ). This air can leave the filtering well (1 ) via the perforation (13) in the lid (11 ).

Figure 6 shows a top view of a filtering well (1 ) for use in an embodiment of the invention. The filtering well (1 ) has a square base and the filter (4) is positioned diagonally to maximise its surface area, which in turn maximises the volume of water that is able to pass through the filter in a given amount of time, i.e. an increased rate of filtration. The storm water enters via the inlet (2), moves from the inlet chamber (5), through the filter (4), into the outlet chamber (6) and exits the filtering well (1 ) via the outlet (3). Figure 6 shows an overflow (14) for excess filtered water to leave the filtering well (1 ), in times of high levels of precipitation,

Figure 7 shows a filter for use in the invention, comprising a frame (9) and a guide (10). In this embodiment, the frame (9) comprises mesh surrounding one side face of the filter. Figure 7 shows a guide (10) for holding the filter in position. The guide secures the filter and frame (9) to the filtering well.

Detailed description

The invention relates to a storm water filtration system comprising:

(i) a storm water drain pit;

(ii) a filtering well for filtering storm water;

(iii) a storm water collection system for storing filtered storm water; wherein the filtering well comprises; an inlet for storm water to enter the filtering well; wherein the inlet is in fluid communication with the storm water drain pit; an outlet for filtered storm water to exit the filtering well; wherein the outlet is in fluid communication with the storm water collection system; a filter comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter divides the filtering well into an inlet chamber and an outlet chamber such that storm water enters via the inlet into the inlet chamber, passes through the filter into the outlet chamber and exits via the outlet.

A storm water filtration system according to an embodiment of the invention is shown in Figures 1 , 2 and 5.

The storm water filtration system is configured such that storm water enters the storm water drain pit and then flows from there into the filtering well, and subsequently on to the storm water collection system. This indicates the flow of water through the filtration system, and hence its connectivity.

In this regard the storm water filtration system may be a self-contained storm water filtration system. This means that the storm water filtration system is not connected to a secondary system, such as a sewage system or other system that discharges storm water.

A storm water drain pit (12) is an underground drain system in which storm water is coarsely filtered (to remove leaves, twigs, sand and other large debris) and channelled into the storm water system. Storm water drain pits are also called storm water drains in the ground, gullies, catch basins or storm water inlets. Typically a storm water drain pit is reached via a permeable grid in the ground i.e. a gridded drain cover which is normally a hinged lid. The term “filtering well” has Its normal meaning in the art. It is an underground or partially underground filter system for filtering storm water. It may also be called a filtering pit, chamber, basin or gully.

The term “storm water” has its usual meaning in the art, and includes water from precipitation such as rain, snow, sleet or hail and water run-off water from residential and commercial areas.

One benefit of the present invention is that the filtering well can be connected to a standard storm water drain pit already present in the ground. This minimises disruption during installation.

Typically, storm water drain pits include a housing, comprising a bottom surface, one or more side surfaces, a hollow centre and a lid. It is a receptacle that is suitable to be buried or partially buried in the ground. Typically, the housing is made from concrete, plastic or cast-iron.

Preferably, the storm water drain pit includes an inlet. Preferably, the inlet is an aperture in the ground, under which the storm water drain pit is buried. The inlet may be any shape i.e. circular, square, rectangular. Preferably, the inlet is circular i.e. a circular hole in the ground leading to the storm water drain pit. Preferably the inlet of the storm water drain pit is integrated into the curb of a pavement or the gutter of a street.

Preferably the inlet is covered with a lid. Preferably the lid is hinged such that it can be opened and closed. This is also known as a drain cover. Preferably the lid is a grid i.e. a cover with perforations. Storm water flows along gutters on the road or pavement, and enters the storm water drain pit, which is underground, via the inlet. Therefore, the lid is permeable to allow water to pass through the inlet. The lid can be any dimension suitable for covering the inlet. For example, the lid may be 20 to 300 cm by 20 to 300 cm. Preferably the storm water drain pit includes a sedimentation chamber, such as a sand trap. The sedimentation chamber is for sedimentation of debris which passes through the inlet into the storm water drain pit. This debris may be anything which passes into the storm water drain system e.g. sand, leaves, twigs and rubbish that might be left on the street, such as cigarette ends and chewing gum. The sedimentation chamber is the volume in the storm water drain pit that is below the outlet. The velocity of the water goes down in the storm water drain pit, thereby all the heavy particles drop to the bottom and form a sedimentation.

Preferably the storm water drain pit comprises an outlet. Preferably the outlet is separated from the sedimentation chamber. Preferably the outlet is positioned above the sedimentation chamber and below the inlet. The outlet conveys water to the inlet of the filtering well, and as such, is in fluid communication with the inlet of the filtering well.

Preferably the storm water drain pit includes a leaf catcher. The leaf catcher may be a perforated plate that covers the outlet. The leaf catcher thus prevents large pieces of debris, such as leaves, from flowing out of the outlet. The perforated plate may be formed of metal, plastic or the like.

In this way, the filtering well and filtration system can be connected to an existing storm water drain pit in the ground. The storm water drain pit coarsely filters the storm water by removing leaves, twigs and other large debris. The storm water is then conveyed to the filtering well where finer filtration occurs, as will be described below. The filtered storm water can then be stored in a storm water collection system. One benefit of this system is that the storm water drain pit can be cleaned as normal, for example every six months with a vacuum cleaner, without the MMVF filter being damaged or having to be removed, since it is in a separate filtering well. Furthermore, the filtering well and storm water collection system may be installed under roads or pavements, beside existing storm water drain pits. This minimises disruption during installation. The filtering well (1 ) is formed of a housing comprising a bottom surface, one or more side walls, a hollow centre and a top surface which may comprise a lid. The filtering well is a receptacle suitable for being buried or partially buried in the ground. Preferably the filtering well housing is formed of concrete, plastic or cast-iron. The housing of the filtering well may be any shape, but preferably it is in the shape of a cylinder, cube or cuboid. When the housing is in the shape of a cuboid, preferably the bottom surface of the housing is square. A filtering well is shown in Figure 3 (side view) and Figure 6 (top view).

Preferably the filtering well is at least partially buried within the ground. Preferably the filtering well is buried in the ground such that the top surface is at ground level i.e. is accessible from the ground.

The top surface preferably comprises a lid (11 ) to provide ventilation as well as access to the filtering well from ground level. The lid is preferably formed of cast iron, plastic or concrete. Preferably the lid is installed in a position in the ground where water does not collect - such as in a pavement. The lid may be impermeable to water along its top face, and allow air to leave the filtering well at the side faces (for example through one or more apertures or perforations 13)). This ensures that only a very small (i.e. negligible) volume of water can enter the filtering well via lid. A perforation (13) is shown in Figures 3 and 5.

The top surface of the filtering well may be partially covered with earth and/or conventional road or pavement materials. The term earth may include sediment, sand, clay, dirt, gravel and the like. Conventional road or pavement materials may include tarmac, asphalt, bitumen, macadam, cobblestones, gravel, sandstone, concrete and the like. However, it is beneficial that the lid of the filtering well is accessible so that the filter may be changed when it becomes soiled/contaminated. This helps to maintain suitable flow of storm water through the system, whilst protecting the storm water collection system from debris and contaminants. Preferably, the filtering well is positioned in the ground beside the storm water drain pit. Preferably the filtering well is within 0.2 m to 5 m of the storm water drain pit.

The filtering well comprises an inlet (2) for storm water to enter the filtering well. Preferably the inlet is the principle route through which storm water can enter the filtering well. The filtering well may contain more than one inlet. The diameter of the inlet may be any size that is capable of being connected to standard sewage pipes. Preferably the inlet has an opening with a diameter in the range of 100 mm to 160 mm, more preferably 110 mm to 125 mm. Preferably the inlet is positioned in a side surface of the housing of the filtering well, at a height that is lower than the top of the filter. This prevents the risk of incoming storm water spilling over the filter. Preferably the inlet is positioned in the lower half of the filtering well side surface, when in use.

In use, the filtering well is buried or partially buried underground, so it is preferred that the inlet is in fluid communication with a conduit which brings storm water to the inlet. The conduit may be an open channel, and water may flow along this channel into the filtering well. Preferably the conduit is a pipe. An advantage of a pipe is that it is hollow and can therefore freely transport water underground to the filtering well. Further, the wall of the pipe prevents debris from entering the pipe.

The inlet of the filtering well is in fluid communication with the storm water drain pit. Preferably, the inlet of the filtering well is in fluid communication with the outlet of the storm water drain pit. This can be achieved by use of a conduit, as described above.

In this way, storm water first enters the storm water drain pit where debris, such as leaves, twigs any coarse particles from the roads, sand, gravel or the like, is removed for example through the use of a sedimentation chamber and/or leaf catcher. The storm water then flows through the outlet of the storm water drain pit into the inlet of the filtering well. The filtering well comprises an outlet (3) for filtered storm water to exit the filtering well. In one embodiment, the outlet is the only route through which filtered storm water can exit the filtering well. In another embodiment, the filtering well may contain more than one outlet. For example, the filtering well according to the present invention may comprise an overflow (14), which can be seen in Figure 6. The overflow is configured such that excess water can flow out of the filtering well. Preferably the overflow is positioned in the outlet chamber, such that excess filtered water flows out of the filtering well. Preferably the overflow is positioned higher than the outlet (3) so that filtered water first exits via the outlet. The overflow can be connected to any system for handling excess water, such as a mains sewer system.

Preferably the outlet has an opening with a diameter in the range of 100 mm to 160 mm, more preferably 110 mm to 125 mm. Preferably the outlet is positioned in a side surface of the housing of the filtering well. Preferably the outlet is positioned in the lower half of the filtering well side surface, when in use. This minimises the amount of water that collects, and stagnates in the well.

The outlet is in fluid communication with a storm water collection system. In use, the filtering well is buried or partially buried underground, so it is preferred that the outlet is in fluid communication with a conduit through which filtered storm water flows to the storm water collection system. Preferably the conduit is a pipe. An advantage of a pipe is that it is hollow and can therefore freely transport filtered storm water to the storm water collection system. Further, the wall of the pipe prevents debris from entering the pipe.

The filtering well comprises a filter (4) that divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6). This can be seen in Figures 3 and 5. The inlet chamber contains the inlet, and as such, storm water enters the filtering well by flowing from the storm water drain pit through the inlet of the filtering well into the inlet chamber. The inlet chamber and the outlet chamber are separated by the filter, such that water must pass through the filter in order to move from the inlet chamber to the outlet chamber. The outlet chamber contains the outlet, and as such, filtered storm water flows from the outlet chamber through the outlet.

Preferably the filter extends along the bottom surface of the filtering well, from one side surface to an opposing side surface thus dividing the filtering well into two separate chambers. In one embodiment, when the housing of the filtering well is cylindrical, the filter extends across the diameter of the filtering well. In another embodiment, when the housing of the filtering well is a cube or cuboid, the filter extends diagonally from one corner to a diagonally opposing corner. This maximises the surface area of the filter and therefore improves the rate of filtration and water flow.

The filter comprises man-made vitreous fibres (MMVF). A filter comprising MMVF is particularly advantageous because it is a sustainable material that can be recycled; it has a very fine pore structure, which means it can filter very fine particles; and it maintains the required flow capacities even when polluted (from filtration). Preferably the filter comprises coherent man-made vitreous fibres (MMVF) bonded with a cured binder composition. By this it is meant that the filter is in the form of a coherent mass of MMVF i.e. a MMVF substrate or slab. That is, the filter is generally a coherent matrix of MMVF fibres bonded with a cured binder composition, which has been produced as such, or has been formed, for example, by granulating a slab of MMVF and consolidating the granulated material. A coherent substrate is a single, unified substrate.

In an alternative embodiment, the filter may comprise granules and/or cubicles of MMVF bonded with a cured binder composition. In this embodiment, the filter is made by packing the granules or cubicles into a filter frame.

In an alternative embodiment, the filter may comprise loose MMVF, for example loose mineral wool, without a cured binder composition. In this embodiment, the filter is made by packing the loose MMVF in a filter frame. The man-made vitreous fibres (MMVF) can be glass fibres, ceramic fibres, basalt fibres, slag wool, stone wool and others, but are usually stone wool fibres. Stone wool generally has a content of iron oxide at least 3% and content of alkaline earth metals (calcium oxide and magnesium oxide) from 10 to 40 %, along with the other usual oxide constituents of MMVF (e.g. silica and alumina). The stone wool generally comprises alkali metals (sodium oxide and potassium oxide), in the range of 1% to 20 %. The stone wool may also include titania and other minor oxides.

Stone fibres commonly comprise the following oxides, in percent by weight:

SiO₂: 30 to 51

AI₂O₃: 12 to 30

CaO: 8 to 30

MgO: 2 to 25

FeO (including Fe₂O3): 2 to 15

Na₂O+K₂O: not more than 10

CaO+MgO: 10 to 30

In preferred embodiments the MMVF have the following levels of elements, calculated as oxides in wt%:

SiO₂: at least 30, 32, 35 or 37; not more than 51 , 48, 45 or 43

AI₂O3: at least 12, 16 or 17; not more than 30, 27 or 25

CaO: at least 8 or 10; not more than 30, 25 or 20

MgO: at least 2 or 5; not more than 25, 20 or 15

FeO (including Fe2O3): at least 4 or 5; not more than 15, 12 or 10

FeO+MgO: at least 10, 12 or 15; not more than 30, 25 or 20

Na₂O+K₂O: zero or at least 1 ; not more than 10

CaO+MgO: at least 10 or 15; not more than 30 or 25

TiO2: zero or at least 1 ; not more than 6, 4 or 2

TiO₂+FeO: at least 4 or 6; not more than 18 or 12

B₂O3: zero or at least 1 ; not more than 5 or 3 P2O5: zero or at least 1 ; not more than 8 or 5

Others: zero or at least 1 ; not more than 8 or 5

The MMVF made by the method of the invention preferably have the composition in wt%:

SiO₂ 35 to 50

AI2O3 12 to 30

TiO₂ up to 2

Fe₂O3 3 to 12

CaO 5 to 30

MgO up to 15

Na₂O 0 to 15

K₂O O to 15

P2O5 up to 3

MnO up to 3

B2O3 up to 3

Another preferred composition for the MMVF is as follows in wt%:

SiO₂ 39-55% preferably 39-52%

AI2O3 16-27% preferably 16-26%

CaO 6-20% preferably 8-18%

MgO 1 -5% preferably 1 -4.9%

Na₂O 0-15% preferably 2-12%

K₂O 0-15% preferably 2-12%

R2O (Na₂O + K₂O) 10-14.7% preferably 10-13.5%

P2O5 0-3% preferably 0-2%

Fe₂O3 (iron total) 3-15% preferably 3.2-8%

B2O3 0-2% preferably 0-1%

TiO₂ 0-2% preferably 0.4-1%

Others 0-2.0% Glass fibres commonly comprise the following oxides, in percent by weight:

SiC : 50 to 70

AI2O3: 10 to 30

CaO: not more than 27

MgO: not more than 12

Glass fibres can also contain the following oxides, in percent by weight: Na2O+K2O: 8 to 18, in particular Na2O+K2O greater than CaO+MgO B2O3: 3 to 12

Some glass fibre compositions can contain AI2O3: less than 2%.

The geometric mean fibre diameter is often in the range of 1.5 to 10 microns, in particular 2 to 8 microns, preferably 2 to 5 microns. The inventors found that this range of geometric fibre diameter positively affects capillarity thus improving filtration.

Preferably, the filter has a density in the range of 40 to 250 kg/m³. This density range ensures that the filter has sufficient strength whilst also having sufficient filtering capacity i.e. the speed at which water can pass through the MMVF filter. If the density is too high, the filter will be strong but will have a lower filtering capacity. Equally, if the density is too low, the filter will not have sufficient strength during use

Preferably, when the filter comprises coherent man-made vitreous fibres (MMVF) bonded with a cured binder composition, the density is in the range of 75 to 200 kg/m³ more preferably 100 to 160 kg/m³.

Preferably, when the filter comprises granules and/or cubicles of MMVF bonded with a cured binder composition or loose MMVF, such as loose mineral wool without a cured binder composition, the density is in the range of 40 to 250 kg/m³, more preferably 40 to 150 kg/m³. For example, the granulate may be packed to a density of 60 to 80 kg/m³, and the cubicles may have a density of 50 to 80 kg/m³.

Preferably, the filter has a binder content in the range of 0% to 10 %, preferably 1% to 10%, more preferably 2% to 5%. This ensures filter is rigid and self- supporting in the sense it can remain upright when positioned in use.

Preferably, when the filter comprises coherent man-made vitreous fibres (MMVF) bonded with a cured binder composition or granules and/or cubicles of MMVF bonded with a cured binder composition, the binder content is in the range of 1% to 10%, more preferably 2% to 5%.

Preferably when the the filter comprises loose MMVF, there is no binder composition present, so the binder content is 0%.

The binder can be an organic hydrophobic binder, and in particular it can be a conventional heat-curable (thermosetting), binder of the type which has been used for many years in MMVF substrates (and other MMVF-based products). This has the advantage of convenience and economy. Thus, the binder is preferably a phenol formaldehyde resin or urea formaldehyde resin, in particular phenol urea formaldehyde (PUF) resin.

The binder may be a formaldehyde-free binder, for example it may comprise a sugar, a furan, a lignin, a hydrocolloid, a carbohydrate, an amine, sulfamic acid or the like as a main component. The formaldehyde-free binder may be as described in any of the following publications: W02004/007615, WO97/07664, WO07129202, WO2017/114724, WO2017/114723 or W02020/070337.

Preferably, the filter is hydrophilic, that is, it does not repel water. Hydrophilic has its normal meaning in the art. An advantage of the filter being hydrophilic is that water passes through the filter at a high speed, increasing the filtration capacity of the filter. In a preferred embodiment, the rate of flow of water is up to 10 litres per second. The hydrophilicity of the filter may be defined in terms of the contact angle with water. Preferably, the MMVF of the filter has a contact angle with water of less than 90°. The contact angle is measured by a sessile drop measurement method. Any sessile drop method can be used, for example with a contact angle goniometer. In practice, a droplet is placed on the solid surface and an image of the drop is recorded in time. The static contact angle is then defined by fitting Young-Laplace equation around the droplet. The contact angle is given by the angle between the calculated drop shape function and the sample surface, the projection of which in the drop image is referred to as the baseline. The equilibrium contact angles are used for further evaluation and calculation of the surface free energy using the Owens, Wendt, Rabel and Kaeble method. The method for calculating the contact angle between material and water is well- known to the skilled person.

Hydrophilicity of the filter may be defined by the hydraulic conductivity. Preferably, the filter has a hydraulic conductivity of 5 m/day to 300 m/day, preferably 50 m/day to 200 m/day. Hydraulic conductivity is measured in accordance with ISO 17312:2005. The advantage of this hydraulic conductivity is that the filter can filter water and transfer it away with sufficient speed to prevent flooding.

The hydrophilicity of a sample of MMVF substrate can be measured by determining the sinking time of a sample. A sample of MMVF substrate having dimensions of 100x100x15 mm to 100x100x100 mm is required for determining the sinking time. A container with a minimum size of 200x200x200 mm is filled with water. The sinking time is the time from when the sample first contacts the water surface to the time when the test specimen is completely submerged. The sample is placed in contact with the water in such a way that a cross-section of 100x100 mm first touches the water. The sample will then need to sink a distance of just over the height of the sample in order to be completely submerged. The faster the sample sinks, the more hydrophilic the sample is. The MMVF substrate is considered hydrophilic if the sinking time is less than 240 s. Preferably the sinking time is less than 100 s, more preferably less than 60 s, most preferably 50 s. In practice, the MMVF substrate may have a sinking time of 50 s or less.

Preferably, the filter is free from oil or substantially free from oil. Preferably, the filter is substantially free from oil. By this, it is meant that the filter comprises only trace amounts of oil, for example less than 0.1 wt% of oil. Most preferably the filter is free from oil. By this it is meant that the filter has 0 wt% of oil. Oil is typically added to MMVF substrates which are to be used for purposes such as sound, insulation, thermal insulation and fire protection. However, the filter is sufficiently hydrophilic to absorb and drain water when it is free from oil or substantially free from oil. In this embodiment, the binder composition may be hydrophilic or hydrophobic, as discussed above. Preferably, when the binder composition is hydrophobic, the filter is free from or substantially free from oil.

The filter may be self-supporting and therefore can be positioned in the filtering well without the requirement for a supporting frame or guide to hold the filter in place.

In a preferred embodiment, the filtering well further comprises a frame (9) for supporting the filter. This can be seen in Figures 3, 5 and 7. The frame may be any material that is capable of supporting the filter, without preventing the filter from functioning i.e. filtering the storm water. For example, the frame may comprise mesh or netting, preferably metal mesh or stretch metal netting. The frame may surround part of the filter, or may surround all faces of the filter.

In a preferred embodiment, the frame may be a U-shape in which the filter sits. By this, it is meant that the frame surrounds the outer perimeter (i.e. edges) of the filter at the sides and the bottom. This ensures that the two faces with the largest surface areas (i.e. the front face which faces the inlet and the back face which faces the outlet) are not covered by the frame, and thus filtration is optimised. In an alternative embodiment, the frame surrounds at least part of the back face of the filter i.e. the face on the side of the outlet. This provides support that resists the direction of flow of water, thus preventing any breakage to the filter. In this embodiment, the frame is preferably a mesh or netting.

Preferably, the frame comprises a hinge which allows the frame to be opened. This ensures that it is easy to maintain or replace the filter held with the frame.

Irrespective of the form of the MMVF material, i.e. granules, cubicles, loose or coherent MMVF, and irrespective of whether the MMVF is bonded, it is particularly beneficial that the filter is easily removable from the filtering well so that it may be replaced when sufficiently fouled. A key benefit of the filter in this case is to protect the storm water collection system from debris and contaminates. This is because the storm water collection system is typically buried underground and therefore it cannot easily be maintained or replaced. Having a removable MMVF filter that is separate to the storm water collection system means that it protects the collection system from contamination. This is particularly important when the storm water protection system is an infiltration system, and even more so when the infiltration system comprises drain elements formed from MMVF as discussed below. In this case, the filter protects the MMVF drain elements from fouling and contamination, and the surrounding ground from pollution. Having a separate filter is also important when the storm water filtration system is a self-contained storm water filtration system.

In a preferred embodiment, the filtering well further comprises a guide (10) for holding the filter in position. The guide secures the filter, which may or may not comprise a frame, to the filtering well. For example, the guide may be a rail into which the filter or filter and frame can be inserted. One of the advantages of the filtering well comprising a guide is that the guide may act as a seal between the the edge of the filter or frame, and the sides of the filtering well. This reduces leakages around the edges of the filter (or frame), so that water (and dirt, particulates and contaminates) cannot leak from the input chamber into the output chamber without passing through the filter. This may ensure that all or most of the storm water passes through the filter and all or most of the water is thus filtered and the particulates and pollutants are removed. The guide may also facilitate ease of removal and replacement of the filter.

The filtering well according to the present invention optionally comprises an air vent (8) that is in fluid communication with a storm water collection system, such that air displaced from the storm water collection system passes into the filtering well. This can be seen clearly in Figures 3, 4 and 5. The filtering well may contain more than one air vent. Preferably the air vent has an opening with a diameter in the range of 40 to 125 mm Preferably the air vent is positioned in a side surface of the housing of the filtering well, preferably in the outlet chamber section. Preferably the air vent is positioned higher in the filtering well than the outlet. Preferably the air vent is positioned in the top half of the filtering well side surface, when in use. This ensures that the air vent can function even when the level of water in the filtering well is high.

Including the air vent in the filtering well is advantageous, as it combines two functions in one well: filtration and ventilation. By allowing air to pass from the storm water collection system to the filtering well, this maximises the amount of water that can be stored in the storm water collection system. Furthermore, this simplifies installation of the filter well and infiltration system, which means less disruption. The air vent can also enable high flow rates through both the filter as well as the collection system.

In use, the filtering well is buried or partially buried underground, so it is preferred that the air vent is in fluid communication with a conduit through which air from the storm water collection system can flow into the filtering well. Preferably the conduit is a pipe. An advantage of a pipe is that it is hollow and can therefore freely transport air from the storm water collection system. Further, the wall of the pipe prevents debris from entering the pipe.

The term “storm water collection system” has its normal meaning in the art. A storm water collection system is capable of absorbing and storing water. A storm water collection system can also transfer the stored water to a water collection point, for use of disposal, or infiltrate into the surrounding ground.

The storm water collection system may be any system known to the skilled person. It may be any system that is capable of absorbing and storing water. For example, in a preferred embodiment, it may be an infiltration system that absorbs water and then allows it to infiltrate into the surrounding ground. It may be a water buffer that absorbs water and holds it until it can be discharged later.

In one embodiment, the storm water collection system may comprise one or more pipes. In one embodiment, the one or more pipes may go further underground than the filtering well, for example 1 m to 100 m underground, so that the water can be transferred into ground that is suitable for infiltration. This may be useful when the top layer of the ground has high amounts of clay, which is unsuitable for infiltration.

In another embodiment, the storm water collection system may comprise a granular material, such as gravel or lava. The void space between the granular material is capable of holding water. The benefit of this is that the granular material is very flexible to install, and can be made into any desired shape.

In another embodiment, the storm water collection system may comprise a receptacle, such as a plastic box, optionally wrapped in geotextile fabric.

In a preferred embodiment, the storm water collection system comprises one or more drain elements, wherein the drain element comprises man-made vitreous fibres bonded with a cured binder composition. The benefit of this storm water collection system is that the drain elements are able to store a high volume of water, much higher than gravel or lava, within the MMVF open pore structure. Furthermore, as the surrounding ground dries out, the water gradually dissipates from the MMVF drain elements into the ground. This provides an effective way to dispose of storm water. Finally, MMVF drain elements are flexible to install, as they can easily be cut on site to any desired shape. The MMVF drain elements may be as described in WO2013/113410 or WO2013/072082.

WO2013/113410 describes a drain element formed of a hydrophilic coherent man-made vitreous fibre substrate (MMVF substrate), wherein the MMVF substrate comprises man-made vitreous fibres bonded with a cured binder composition, the MMVF substrate having opposed first and second ends and a passage which extends from a first opening in the first end to a second opening in the second end.

WO2013/072082 describes a water drain reservoir comprising a coherent manmade vitreous fibre substrate (MMVF substrate) and a conduit having two open ends, wherein the MMVF substrate comprises man-made vitreous fibres bonded with a cured binder composition, wherein a first open end of the conduit is in fluid communication with the MMVF substrate.

In view of the above and the purpose of the invention, a particularly preferred embodiment of the invention is a storm water filtration system, comprising:

(i) a storm water drain pit (12);

(ii) a filtering well (1 ) for filtering storm water;

(iii) a storm water collection system (7) for storing filtered storm water, wherein the storm water collection system is an infiltration system that allows the filtered storm water to infiltrate into surrounding ground; wherein the filtering well comprises; an inlet (2) for storm water to enter the filtering well; wherein the inlet (2) is in fluid communication with the storm water drain pit; an outlet (3) for filtered storm water to exit the filtering well; wherein the outlet (3) is in fluid communication with the storm water collection system (7); a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3).

The above storm water filtration system may be a self-contained storm water filtration system. This means that it does not need to be connected to a secondary system, such as a sewage system or other system that discharges storm water. The filter may be easily removed from the self-contained unit to be replaced or cleaned.

In a preferred embodiment, the above storm water filtration system comprising an infiltration system comprises one or more drain elements, wherein the drain element comprises man-made vitreous fibres bonded with a cured binder composition.

The above storm water filtration system comprising an infiltration system may be beneficial due to the filter being able to remove pollutants, contaminants, particulates and debris from the storm water, before the filtered water is dissipated into the surrounding ground, which reduces the potential for ground pollution. This may be particularly beneficial in urban areas, including industrial areas, where pollution from pollutants, contaminants, particulates and debris, is likely to be more prevalent in the storm water.

In this case it is preferred that the filter in the filtering well is removable and replaceable. This means that it can be removed and replaced when it has become fouled as it protects the storm water collection system (especially an infiltration system) from debris or contamination. Again, this is particularly advantageous as the storm water collection system is typically buried underground and would be difficult to clean and need to be excavated if it is to be replaced. The filter may be referred to as a sacrificial filter. To achieve this the filtering well may comprise a guide (10) for holding the filter in position. The guide secures the filter, which may or may not comprise a frame, to the filtering well. For example, the guide may be a rail into which the filter or filter and frame can be inserted.

The binder composition in the drain element may be as described above for the filter.

The storm water collection system preferably comprises an air vent. Preferably the air vent is an aperture through which air that is displaced as water enters the storm water collection system can exit. Preferably the air vent is formed by inserting a pipe from ground level into the storm water collection system.

In a preferred embodiment, the outlet of the filtering well is connected to a MMVF drain element via a conduit, preferably a pipe. An MMVF drain element can butt up against the conduit, preferably a pipe, through which filtered storm water will flow, in order to achieve this fluid communication. It is preferable however for efficiency for the conduit to be at least partially embedded into the MMVF drain element. The embedded part of the conduit may have an aperture in its outer wall, preferably more than one aperture. The presence of an aperture has the advantage of there being a greater area through which the water can flow into the drain element.

The MMVF drain element may have a passagelch extends from a first end of the drain element, towards a second end of the drain element, wherein the first and second ends are opposed and wherein the first end of the passage is in fluid communication with water from filtering well. The passage may extend 10 % to 100 % of the way through the drain element, preferably 20 % to 99 % of the way through the drain element, preferably 50% to 99 % of the way through the drain element, more preferably 80 % to 95 % of the way through the substrate. The advantage of the passage is that there is a greater area through which the water can flow into the drain element. The passage may have any cross-sectional shape, preferably circular, triangular or square. The storm water collection system may comprise more than one drain element, preferably a series of drain elements, which may be connected together to increase the volume of water that can be stored and then dissipated. These drain elements may be placed next to each other so that water can dissipate from one drain element to the next. Alternatively, a conduit, preferably a pipe, with apertures can run through a first drain element, and then be at least partially embedded into a second drain element. This allows any water which is not absorbed by the first drain element to flow into the second drain element and so on, for any further drain elements in the storm water collection system.

Preferably the water holding capacity of the drain element is at least 80% of the volume, preferably 80-99 %, most preferably 85-95 %. The greater the water holding capacity, the more water that can be stored for a given volume. The water holding capacity of the drain element is high due to the open pore structure of MMVF.

Preferably the amount of water that is retained by the drain element when it gives off water is less than 20 %vol, preferably less than 10 %vol, most preferably less than 5%vol. The water retained may be 2 to 20 %vol, such as 5 to 10 %vol. The lower the amount of water retained by the drain element, the greater the capacity of the drain element to take on more water. Water may leave the drain element by dissipating into the ground when the surrounding ground is dry and the capillary balance is such that the water dissipates into the ground.

Preferably the buffering capacity of the drain element, that is the difference between the maximum amount of water that can be held, and the amount of water that is retained when the drain element gives off water is at least 60 %vol, preferably at least 70 %vol, preferably at least 80 %vol. The buffering capacity may be 60 to 90 %vol, such as 60 to 85 %vol. The advantage of such a high buffering capacity is that the drain element can buffer more water for a given volume, that is the drain element can store a high volume of water when it rains, and release a high volume of water as the surrounding ground dries out. The buffering capacity is so high because drain element requires a low suction pressure to remove water from the drain element.

The water holding capacity, the amount of water retained and the buffering capacity of the drain element can be measured in accordance with EN 13041 - 1999.

The present invention also relates to a method of filtering and storing storm water comprising the steps of:

- providing a storm water filtration system as described herein;

- allowing water to flow from the storm water drain pit into the inlet chamber of the filtering well via the inlet;

- allowing the storm water to pass from the inlet chamber to the outlet chamber through the filter;

- allowing the filtered storm water to exit the filtering well via the outlet into the filtration system for storage.

The storm water filtration system may comprise any of the preferred features discussed above, in particular it is preferred that storage is in an infiltration system (preferably infiltration system comprising MMVF as discussed above).

The present invention also relates to a method of installing a storm water filtration system, comprising the steps of;

- identifying a storm water drain pit in the ground or positioning a storm water drain pit in the ground;

- positioning a filtering well in the ground, wherein the filtering well comprises; an inlet for storm water to enter the filtering well; wherein the inlet is in fluid communication with the storm water drain pit; an outlet for filtered storm water to exit the filtering well; a filter comprising coherent man-made vitreous fibres (MMVF) bonded with a cured binder composition for removing particles from the storm water, wherein the filter divides the filtering well into an inlet chamber and an outlet chamber such that storm water enters via the inlet into the inlet chamber, passes through the filter into the outlet chamber and exits via the outlet;

- positioning a storm water collection system in ground, wherein the outlet of the filtering well is in fluid communication with the storm water collection system.

The storm water filtration system may comprise any of the preferred features discussed above, in particular it is preferred that the collection system is an infiltration system (preferably infiltration system comprising MMVF as discussed above).

Example

A storm water filtration system according to the present invention was tested to measure the water flow.

A pump with a capacity of 150-200 m3/hour was used to pump water via an inlet into a storm water drain pit according to the present invention. From this storm water drain pit, the water flowed directly to a filtering well with a filter according to the invention. Water then flowed through the filter and out through an outlet.

The storm water drain pit and the filtering well had internal dimensions of 350x350x825mm. The filtering well had a water inlet (0 125mm) at 400 mm (from inside bottom), a 0 125mm drainpipe at 70 mm, an 0 125mm overflow at 400 mm from the bottom with siphon and a 0 50mm air vent in fluid communication with a storm water collection system (comprising MMVF). The filter, comprising MMVF bonded with a cured binder composition, measured 395x20x650 mm and was positioned diagonally in the filtering well. The filter comprised a stainless-steel holder frame. The input flow was measured in m3/hour in relation to water level. A flow rate of 25 m3/hour was measured.

Numbered embodiments The following numbered embodiments provide further non-limiting embodiments of the invention.

Embodiment 1. A filtering well (1 ) comprising: an inlet (2) for storm water to enter the filtering well; an outlet (3) for filtered storm water to exit the filtering well; a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3); wherein the outlet (3) is configured to be connectable to a storm water collection system (7) for storing filtered storm water; and an air vent (8) configured to be connectable to a storm water collection system (7) such that air displaced from the storm water collection system (7) passes into the filtering well via the air vent.

Embodiment 2. The filtering well (1 ) according to embodiment 1 , wherein the filter (4) has a density in the range of 40 to 250 kg/m³, preferably 75 to 200 kg/m³, more preferably 100 to 160 kg/m³.

Embodiment 3. The filtering well (1 ) according to embodiment 1 or 2, wherein the man-made vitreous fibres in the filter (4) have a geometric fibre diameter of 1 .5 to 10 microns, preferably 2 to 8 microns, more preferably 2 to 5 microns.

Embodiment 4. The filtering well (1 ) according to any preceding embodiment, wherein the filter comprises coherent man-made vitreous fibres (MMVF) bonded with a cured binder composition.

Embodiment 5. The filtering well (1 ) according to any preceding embodiment, wherein the filter (4) has a contact angle with water of less than 90° and/or a hydraulic conductivity of 5 m/day to 300 m/day, preferably 50 m/day to 200 m/day.

Embodiment 6. The filtering well (1 ) according to any preceding embodiment, wherein the filter (4) further comprises a frame (9) for support.

Embodiment 7. The filtering well (1 ) according to any preceding embodiment further comprising a guide (10) for holding the filter (4) in position.

Embodiment 8. The filtering well (1 ) according to any preceding embodiment in the shape of a cylinder, cube or cuboid.

Embodiment 9. The filtering well (1 ) according to any preceding embodiment, further comprising a lid (11 ), preferably wherein the lid comprises a water impermeable top face and at least one perforation (13) at a side face.

Embodiment 10. The filtering well (1 ) according to any preceding embodiment positioned under the ground, preferably under a road or pavement.

Embodiment 11. Use of a filtering well (1 ) according to any preceding embodiment for filtering storm water.

Embodiment 12. A method of filtering storm water comprising the steps of:

- providing a filtering well (1 ) according to any of embodiments 1 to 10;

- allowing storm water to enter the filtering well (1 ) via the inlet (2) into the inlet chamber (5);

- allowing the storm water to pass from the inlet chamber (5) to the outlet chamber (6) through the filter (4) to produce filtered storm water;

- allowing the filtered storm water to exit the outlet chamber (6) via the outlet (3). Embodiment 13. A method of installing a filtration system comprising, positioning at least one filtering well (1 ) according to any of embodiments 1 to 10 in the ground.

Embodiment 14. A storm water filtration system comprising:

(i) a filtering well (1 ) for filtering storm water:

(ii) a storm water collection system (7) for storing filtered storm water; wherein the filtering well comprises; an inlet (2) for storm water to enter the filtering well; an outlet (3) for filtered storm water to exit the filtering well; wherein the outlet (3) is in fluid communication with the storm water collection system (7); a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3); and an air vent (8) in fluid communication with the storm water collection system (7) such that air displaced from the storm water collection system (7) passes into the filtering well via the air vent.

Embodiment 15. The storm water filtration system according to embodiment 14, wherein the storm water collection system comprises one or more drain elements, wherein the drain element comprises man-made vitreous fibres bonded with a cured binder composition.

Embodiment 16. A method of filtering and storing storm water comprising the steps of:

- providing a storm water filtration system according to embodiment 14;

- allowing storm water to enter the filtering well (1 ) via the inlet (2) into the inlet chamber (5); - allowing the storm water to pass from the inlet chamber (5) to the outlet chamber (6) through the filter (4);

- allowing the filtered storm water to exit the filtering well via the outlet (3) into the storm water collection system (7) for storage;

- allowing air displaced from the storm water collection system (7) to pass into the filtering well via the air vent (8).

Embodiment 17. A storm water filtration system comprising:

(i) a storm water drain pit (12);

(ii) a filtering well (1 ) for filtering storm water;

(iii) a storm water collection system (7) for storing filtered storm water; wherein the filtering well comprises; an inlet (2) for storm water to enter the filtering well; wherein the inlet (2) is in fluid communication with the storm water drain pit; an outlet (3) for filtered storm water to exit the filtering well; wherein the outlet (3) is in fluid communication with the storm water collection system (7); a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3); and an air vent (8) in fluid communication with the storm water collection system (7) such that air displaced from the storm water collection system (7) passes into the filtering well via the air vent.

Embodiment 18. The storm water filtration system according to embodiment 14, 15 or 17, wherein the storm water filtration system is a self-contained storm water filtration system.

Claims

36 Claims

1 . A storm water filtration system comprising:

(i) a storm water drain pit (12);

(ii) a filtering well (1 ) for filtering storm water;

2. The storm water filtration system according to claim 1 , wherein the storm water collection system is an infiltration system that allows the filtered storm water to infiltrate into surrounding ground.

3. The storm water filtration system according to claim 1 or 2, wherein the filter (4) has a density in the range of 40 to 250 kg/m³ preferably 75 to 200 kg/m³, more preferably 100 to 160 kg/m³.

4. The storm water filtration system according to any preceding claim, wherein the man-made vitreous fibres in the filter (4) have a geometric fibre diameter of 1.5 to 10 microns, preferably 2 to 8 microns, more preferably 2 to 5 microns. 37

5. The storm water filtration system according to any preceding claim, wherein the filter comprises coherent man-made vitreous fibres (MMVF) bonded with a cured binder composition.

6. The storm water filtration system according to any preceding claim, wherein the filter (4) has a contact angle with water of less than 90° and/or a hydraulic conductivity of 5 m/day to 300 m/day, preferably 50 m/day to 200 m/day.

7. The storm water filtration system according to any preceding claim, wherein the filtering well further comprises an air vent (8) in fluid communication with the storm water collection system (7) such that air displaced from the storm water collection system (7) passes into the filtering well via the air vent.

8. The storm water filtration system according to any preceding claim, wherein the filter further comprises a frame (9) for support.

9. The storm water filtration system according to any preceding claim, wherein the filtering well further comprises a guide (10) for holding the filter (4) in position.

10. The storm water filtration system according to any preceding claim, wherein the filtering well is in the shape of a cylinder, cube or cuboid.

11. The storm water filtration system according to any preceding claim, wherein the filtering well further comprises a lid (11 ), preferably wherein the lid comprises a water impermeable top face and at least one perforation at a side face.

12. The storm water filtration system according to any preceding claim positioned under a ground, preferably under a road or pavement.

13. The storm water filtration system according to any preceding claim, wherein the storm water collection system comprises one or more drain elements, wherein the drain element comprises man-made vitreous fibres bonded with a cured binder composition.

14. The storm water filtration system according to any preceding claim, wherein the storm water drain pit comprises; an inlet for storm water to enter the storm water drain system; a sedimentation chamber for sedimentation of debris from the storm water; an outlet, for storm water to exit the storm water drain pit, wherein the outlet is in fluid communication with the inlet of the filtering well.

15. The storm water filtration system according to claim 14, wherein the storm water drain pit further comprises a separation element for separating the sedimentation chamber from the outlet, and wherein the outlet is positioned above the sedimentation chamber and below the inlet.

16. The storm water filtration system according to any proceeding claim, wherein the storm water filtration system is a self-contained storm water filtration system.

17. A method of filtering and storing storm water comprising the steps of:

- providing a storm water filtration system according to any of claims 1 to 16;

18. A method of installing a storm water filtration system, comprising the steps of;

- positioning a filtering well in the ground, wherein the filtering well comprises; an inlet (2) for storm water to enter the filtering well; wherein the inlet (2) is in fluid communication with the storm water drain pit; an outlet (3) for filtered storm water to exit the filtering well; a filter (4) comprising man-made vitreous fibres (MMVF) for removing particles from the storm water, wherein the filter (4) divides the filtering well (1 ) into an inlet chamber (5) and an outlet chamber (6) such that storm water enters via the inlet (2) into the inlet chamber (5), passes through the filter (4) into the outlet chamber (6) and exits via the outlet (3);