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Title:
STORAGE CONTAINER
Document Type and Number:
WIPO Patent Application WO/2008/119137
Kind Code:
A1
Abstract:
A storage container for holding particulate material in a body of water, the container formed from a plastics material which is impervious to water and defining a space in which the particulate material may be held, wherein the container is arranged to sink to the floor of the body of water upon receipt in the space defined by the container of a sufficient amount of particulate material.

Inventors:
MEARNS, Brian (Level 23, 127 Creek StreetBrisbane, Queensland 4000, AU)
MILLS, David (Level 23, 127 Creek StreetBrisbane, Queensland 4000, AU)
PEARCE, Clive (Level 23, 127 Creek StreetBrisbane, Queensland 4000, AU)
Application Number:
AU2008/000479
Publication Date:
October 09, 2008
Filing Date:
April 03, 2008
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
TAUPO MARITIME PTY LTD (Level 23, 127 Creek StreetBrisbane, Queensland 4000, AU)
MEARNS, Brian (Level 23, 127 Creek StreetBrisbane, Queensland 4000, AU)
MILLS, David (Level 23, 127 Creek StreetBrisbane, Queensland 4000, AU)
PEARCE, Clive (Level 23, 127 Creek StreetBrisbane, Queensland 4000, AU)
International Classes:
E02F7/00; B65D88/78; E02F5/24; E02F5/28; E02F5/30; E02F9/00
Domestic Patent References:
1999-01-28
Foreign References:
US6718900B22004-04-13
US4480569A1984-11-06
Other References:
DATABASE WPI Week 198526, Derwent Publications Ltd., London, GB; Class P43, AN 1985-156618 & JP 60 088694 A (NIPPON STEEL CORP) 18 May 1985
Attorney, Agent or Firm:
GRIFFITH HACK (Level 10, 167 Eagle StreetBrisbane, Queensland 4001, AU)
Download PDF:
Claims:

Claims

1. A storage container for holding particulate material in a body of water, the container formed from a plastics material which is impervious to water and defining a space in which the particulate material may be held, wherein the container is arranged to sink to the floor of the body of water upon receipt in the space defined by the container of a sufficient amount of particulate material.

2. A storage container as claimed in claim 1, wherein the container is expandable.

3. A storage container as claimed in either claim one or claim 2, wherein the container is formed from at least one sheet.

4. A storage container as claimed in any one of the preceding claims, wherein the container is formed from at least three sheets; a top sheet, a bottom sheet and at least one middle sheet for spacing apart the top and bottom sheets and defining the space therebetween.

5. A storage container as claimed in either claim 3 or claim 4, wherein the at least one sheet has a thickness of 0.5 to 10mm.

6. A storage container as claimed in any one of the preceding claims, wherein the container comprises an inlet for inputting the particulate material to the space.

7. A storage container as claimed in claim 6, wherein the container comprises a sealable portion for sealing the inlet closed after particulate material has been received in the space.

8. A storage container as claimed in any one of the preceding claims, the container also comprising at least one vent for releasing gas from the space.

9. A storage container as claimed in claim δ, wherein each vent comprises an aperture in the container.

10. A storage container as claimed in either claim 8 or claim 9, wherein the container comprises a valve for each vent.

11. A storage container as claimed in claim 10, wherein each valve is in the form of a flap.

12. A storage container as claimed in claim 11, wherein each flap has an attachment portion which is joined to an outer surface of the container.

13. A storage container as claimed in either claim 11 or claim 12, wherein the attachment portion of each flap is located in relation to its respective vent to enable the container, in use, to be positioned whereby a substantial component of a flow of water past the container biases each flap towards a covering position whereby it is covering its respective vent.

14. A storage container as claimed in claim 11, wherein the container also comprises at least one group of three connecting elements for each flap, arranged in a triangular formation for selectively connecting each flap to two of the three connecting elements .

15. A storage container as claimed in claim 14, wherein each vent is formed in an appropriate location after the connecting elements to which its respective flap is to be connected have been selected.

16. A storage element as claimed in either claims 14 or 15, wherein the connecting elements comprise clips and the flaps have suitable elements to be received in the clips.

17. A storage container as claimed in any one of the preceding claims, wherein the container also comprises at least one flow indicator for indicating the direction of flow of water past the container.

18. A storage container as claimed in any one of the preceding claims, wherein the container also comprises at least one towing anchor for connecting to a ship to move the container through the water.

19. A storage container as claimed in any one of the preceding claims, wherein at least a portion of the container is formed from a stretchable material.

20. A storage container as claimed in claim 19, wherein the stretchable material is stretchable by at least 200%.

21. A storage container as claimed in any one of the preceding claims, wherein at least a portion of the container is formed from a biodegradable material .

22. A storage container as claimed in any one of the preceding claims, wherein the container also comprises perforated tubing for inflating and deflating the container with air.

23. A method for holding particulate material in a body of water, the method comprising the steps of positioning a storage container as claimed in any one of claims 1 to 22 in the body of water; and inputting the particulate material to the space defined by the

container.

24. A method as claimed in claim 23, wherein the step of positioning the container comprises towing the container to a desired position.

25. A method as claimed in either claims 23 or 24, wherein the method also comprises the step of at least partially inflating the container with air to enable it to float in the body of water.

26. A method as claimed in any one of claims 23 to 25, wherein the step of inputting the particulate material comprises pumping the particulate material as a slurry into the container space using a pump.

27. A method as claimed in any one of claims 23 to 26, wherein the step of inputting the particulate material occurs concurrently with dredging of the particulate material.

28. A method as claimed in any one of claims 23 to 27, wherein as the step of inputting occurs the space increases in volume.

29. A method as claimed in any one of claims 23 to 28, also comprising inputting the particulate material through an inlet of the container and then closing the inlet once the step of inputting the particulate material has finished.

30. A method as claimed in any one of claims 23 to 29, wherein the method also comprises the step of orientating the container so that a substantial component of a flow of water past the container biases flaps of the container towards a covering position where each flap is covering a respective vent of the container for releasing

gas from the container space.

31. A method as claimed in claim 30, wherein the method also comprises the steps of selecting two connection elements from groups of three connecting elements formed on a surface of the container and connecting the flaps to the selected connection elements.

32. A method as claimed in claim 31, wherein the step of selecting involves using a flow indicator of the container .

33. A method as claimed in any one of claims 30 to 32, the method also comprising the step of forming each vent in an appropriate location.

34. A method for reinforcing or constructing a navigation channel in a waterway, the method comprising the steps of: positioning a first storage container which is a container as claimed in any one of claims 1 to 22 in the waterway at or above a location which is or will be a side of the channel; dredging particulate material from or to form the channel; and inputting at least some of the dredged particulate material into the space defined by the first container.

35. A method as claimed in claim 34, wherein the method further comprises the steps of positioning a second storage container which is a container as claimed in any one of claims 1 to 22 in the waterway at or above a location which is or will be a side of the channel and inputting at least some of the dredged particulate material into the space defined by the second container.

Description:

STORAGE CONTAINER

Field of the Invention

The present invention relates to a storage container for holding particulate material in a body of water, in particular to holding waste material from dredging. The present invention also relates to a method for holding particulate material in a body of water and to a method for reinforcing or constructing a navigation channel in a waterway.

Background of the Invention

Dredging of at least partly submerged silts, soils and other particulate matter may be carried out for various reasons, such as for widening, deepening or maintaining navigation channels in various waterways, land reclamation and erosion control, or to mine sand for various usages, including concrete production.

However, the process of dredging produces high volumes of waste material, which may be referred to as

"marine mud", "bay mud" or "dredging spoils". The amount of this material produced may be as much as 6,000 to 10,000 m 3 per hour, or even more. Disposal of this high volume of waste material is problematic because of its significant environmental impacts. Two options are generally available for disposal of dredging waste material; either returning it to the waterway, usually at another location from which it was dredged, or depositing the material on land. The first option of disposing the waste material in water creates a large increase in the turbidity of the water at the disposal site. This increase in turbidity can kill seagrass beds as well as negatively affect the metabolism and spawning of various animals. This in turn can have significant ecological impacts on animals higher in the food chain.

Disposing of the dredging waste material on land

presents other problems. In particular, it has been found that where this material is left to dry out, reactions occur within the material which lead to the formation of various sulphates. Consequently, when this material becomes wet again, by for example rain, sulphuric acid (H 2 SO 4 ) is formed, which is extremely harmful to the environment.

As an alternative to the above disposal methods, the dredging waste material may be stored in specially constructed land based disposal ponds. However, this requires the construction of large and ever increasing infrastructure to hold the waste material and furthermore, may require the transportation of the waste material over significant distances. Given the high volumes of waste material produced by dredging, in many situations, the transportation of the waste material to disposal ponds may not be commercially viable.

Summary of the Invention According to a first aspect of the present invention, there is provided a storage container for holding particulate material in a body of water, the container formed from a plastics material which is impervious to water and defining a space in which the particulate material may be held, wherein the container is arranged to sink to the floor of the body of water upon receipt in the space defined by the container of a sufficient amount of particulate material.

Typically, the particulate material is waste material, such as waste material from dredging, which may also be referred to as "marine mud", "bay mud", or "dredging spoils". It is to be understood, however, that the container may be used for holding other particulate materials such as sand, non-toxic industrial sludge or toxic particulate material, for example.

In an embodiment, the container is expandable. This enables the space defined by the container, in which

the particulate material is held, to increase.

Preferably, the container is expandable under the action of inputting the particulate material to the space .

Xn an embodiment, the container is formed from at least one sheet.

In an embodiment, the container is expandable due to the stretchability of the at least one sheet from which the container is formed.

In an embodiment, the at least one sheet has a thickness of 0.5 to 10 mm, preferably 1.0 to 4.0 mm, more preferably 1.5 to 3.5 mm.

In one embodiment, the container is formed from one sheet. In this embodiment, the sheet is folded to define two portions of the sheet, the two portions being joined where they overlap to define the space in which the particulate material may be held.

Preferably, the two portions are joined at or near the edges of where they overlap.

In an embodiment, the joints are formed by fusion or heat-welding.

In an embodiment, the two portions are identical to one another, ie. the sheet is folded in half. However, this need not be the case.

In another embodiment, the container is formed from two sheets.

In this embodiment, the sheets are positioned one on top of the other and joined where they overlap to define the space in which the particulate material may be held. Preferably, the two portions are joined at or near the edges of where they overlap.

In an embodiment, the joints are formed by fusion or heat-welding.

In another embodiment, the container is formed from at least three sheets; a top sheet, a bottom sheet and at least one middle sheet for spacing apart the top and bottom sheets and defining the space therebetween.

In an embodiment, the sheets are joined by fusion or heat-welding.

In an embodiment, the container has four middle sheets which space apart opposing edges of the top and bottom sheets.

Thus, in this embodiment, the container has an approximately rectangular prism shape. The shape of the container, however, may be distorted by the amount of particulate material held in the container. The container may also be provided with a cylindrical shape or any other shape as required.

In an embodiment, the container comprises an inlet for inputting the particulate material to the space.

Preferably, the inlet is formed through a top sheet of the container.

In an embodiment, the inlet is located substantially centrally in the top sheet of the container.

In an embodiment, the inlet comprises a tube projecting from a surface of the container. In an embodiment, the container comprises multiple inlets. The multiple inlets may or may not be used simultaneously.

In an embodiment, the container comprises a sealable portion for sealing the inlet closed after the particulate material has been received in the space.

The sealable portion may be sealed by crimping or clamping the inlet tube.

In an embodiment, sealing the inlet closed, seals the space closed and there are no other apertures through the container to the space.

However, in another embodiment, the space is not completely sealed closed.

In an embodiment, the container also comprises at least one vent for releasing gas from the space. Preferably, the container comprises a plurality of vents.

The gas is typically methane gas, which is a byproduct of the breakdown of organic matter in the

particulate material (in particular where the particulate material is waste material from dredging) .

In an embodiment, each vent comprises an aperture in the container, preferably in the top sheet of the container.

The vents may or may not be identical to one another.

In an embodiment, the inlet comprises one of the vents . In an embodiment, the container comprises a valve for each vent.

The valve (s) reduce the loss of particulate material held in the space defined by the container whilst still allowing the gas to be released through the vent(s). In an embodiment, each valve is in the form of a flap.

Some of the flaps may be joined together to provide a single flap for a number of vents.

However, in other embodiments the valve (s) may be any other suitable valve mechanism which allows release of gas through the vent(s) but with retention of the particulate material. For example, the valve (s) may be a bubble valve.

In an embodiment, each flap has a surface area which is greater than the cross-sectional area of its respective vent .

In the embodiment where the inlet comprises one of the vents, the sealable portion may comprise the flap for covering that vent. The flaps may or may not be identical to one another.

In an embodiment, each flap has an attachment portion which is joined to an outer surface of the container, preferably to the outer surface of the top sheet of the container.

In an embodiment, the attachment portion of each flap is joined to the outer surface of the container by

fusion or heat-welding.

In an embodiment, the attachment portion comprises one side of each flap.

In an embodiment, each flap is rotatable about the attachment portion. Each flap is rotatable between a covering position and an open position. In the covering position, each flap is covering its respective vent. In the open position, each flap is exposing its respective vent. In an embodiment, the attachment portion of each flap is located in the same direction from its respective vent.

In an embodiment, the attachment portion of each flap is located in relation to its respective vent to enable the container, in use, to be positioned whereby a substantial component of a flow of water past the container biases each flap towards its covering position where it is covering its respective vent.

This bias acts against the flaps undesirably "lifting" away towards its open position and opening the vents due to the flow of water past the container, which might result in undue loss of particulate material from the space in the container. However, the flaps may still be moved towards their open position by any gas as it escapes from the space through the vents.

However, the attachment portions of each flap need not be joined in this orientation.

In another embodiment, each flap is joined to the outer surface of the container by two attachment portions, preferably to the outer surface of the top sheet of the container.

The two attachment portions may be separate from or adjoining one another.

In an embodiment, the two attachment portions are at an angle to one another which is greater or less than 180°.

In another embodiment, the two attachment

portions are on opposing sides of each flap.

The two attachment portions restrict the movement of each flap away from the vent. This acts against the flaps undesirably "lifting" away and opening the vents due to the flow of water past the container.

Zn another embodiment/ the container also comprises at least one group of three connecting elements for each flap, arranged in a triangular formation for selectively connecting each flap to two of the three connecting elements.

The selection of the connecting elements is generally dependent on the direction of flow of water past the container. Each flap can be connected to the appropriate connecting elements whereby a substantial component of the flow of water past the container biases each flap towards its covering position where it is covering its respective vent.

In an embodiment, the at least one group of connecting elements are located on an outer surface of the container, preferably on the outer surface of a top sheet of the container.

In an embodiment, each vent is formed in an appropriate location after the connecting elements to which its respective flap is to be connected have been selected.

In an embodiment, each vent is formed by piercing the outer surface of the container.

In an embodiment, the connecting elements comprise clips. In an embodiment, the flaps have suitable elements to be received in the clips.

The connecting elements enable the flap to be connected in four different orientations.

The four different orientations are preferably at right angles to one another.

In an embodiment, the container also comprises at least one flow indicator for indicating the direction of

flow of water past the container.

In an embodiment, a flow indicator is connected to the container in close proximity to each group of connecting elements. In an embodiment, each flow indicator comprises a strip of material.

In an embodiment, the container also comprises at least one towing anchor for connecting to a ship to move the container through the water. In an embodiment, the at least one towing anchor is connected to an outer surface of the container, preferably to the outer surface of the bottom sheet of the container.

In an embodiment, the at least one towing anchor comprises a solid ring.

In an embodiment, the ring has a thickness of approximately 50 mm.

In an embodiment, the at least one towing anchor is fusion or heat welded to the outer surface of the container.

In an embodiment, the container comprises four towing anchors; preferably, one located at each corner of the top sheet.

In an embodiment, the container comprises eight towing anchors; preferably, one located at each corner of the top and bottom sheet.

In an embodiment, at least a portion of the container is formed from a stretchable material.

In an embodiment, most of the container is formed from a stretchable material.

In an embodiment, the at least one sheet of the container is formed from a stretchable material.

The stretchable material is preferably stretchable at least 200%, more preferably at least 500%, even more preferably at least 800%.

In an embodiment, the plastics material is high density polyethylene (HDPE) or polyvinyl chloride (PVC) .

In an embodiment, at least a portion of the container is formed from a biodegradable material. In this embodiment, the particulate material is only temporarily held in the container. In an embodiment, most of the container is formed from a biodegradable material.

In an embodiment, the at least one sheet of the container is formed from biodegradable material.

In an embodiment, each flap is formed from the same material as the at least one sheet.

In an embodiment, the at least one towing anchor is formed from the same or similar material as the at least one sheet of the container, for example HDPE or PVC.

In an embodiment, the container also comprises perforated tubing for inflating and deflating the container with air.

In an embodiment, the perforated tubing is located at the sides of the container.

In an embodiment, the perforated tubing comprises HDPE or PVC tubing.

In an embodiment, the perforated tubing has a diameter of approximately 50mm.

In an embodiment, the perforated tubing is heat or fusion welded to an inner surface of the container. In an embodiment, the perforated tubing is located around the perimeter of the space defined by the container.

According to a second aspect of the present invention, there is provided a method for holding particulate material in a body of water, the method comprising the steps of: positioning a storage container according to the first aspect of the present invention in the body of water; and inputting the particulate material to the space defined by the container.

The above steps may be conducted in no particular

order, although preferably the step of positioning the container in the water occurs first.

In an embodiment, the step of positioning the container comprises towing the container to a desired position.

In an embodiment, the method also comprises the step of connecting the container via the or at least one of the towing anchors to a ship.

Preferably, the ship is a dredge. In an embodiment, the method also comprises the step of at least partially inflating the container with air to enable it to float in the body of water.

In an embodiment, the step of inputting the particulate material comprises pumping the particulate material as a slurry into the container space using a pump.

In an embodiment, the step of inputting occurs concurrently with dredging of the particulate material .

In another embodiment, the particulate material is pumped from a holding vessel subsequent to having been dredged. In an embodiment, the holding vessel is on a dredge .

In an embodiment, the step of inputting the particulate material comprises spraying the particulate material towards all sides of the space defined by the container.

In an embodiment, as the step of inputting occurs, the container sinks to the floor of the body of water. In an embodiment, as the step of inputting occurs the space increases in volume.

In an embodiment, the method also comprises the step of connecting a feed pipe to the container inlet to input from a source of the particulate material. Preferably, the feed pipe is the pipe from a dredge .

In an embodiment, the method also comprises the

step of closing the inlet once the step of inputting the particulate material has finished.

In an embodiment, the step of closing the inlet comprises sealing the sealable portion to seal the inlet closed, by for example crimping or clamping the inlet tube.

In another embodiment, the step of closing the inlet comprises any other suitable means of obstructing the inlet. In an embodiment, the method also comprises the step of disconnecting the feed pipe from the inlet once the step of inputting the particulate matter has finished. This step may occur before or after the step of closing the inlet. In an embodiment, the method also comprises the step of orientating the container so that a substantial component of a flow of water past the container biases each flap towards its covering position where it is covering its respective vent. In another embodiment, the method also comprises the steps of selecting two connection elements from the groups of three connection elements to connect each flap to and connecting the flaps to the selected connection elements . In an embodiment, the step of selecting involves using the flow indicators.

In an embodiment, the method also comprises the step of forming each vent in an appropriate location.

In an embodiment, the step of forming each vent includes piercing an outer surface of the container, preferably the outer surface of the top sheet of the container.

In an embodiment, the step for forming each vent occurs after the step of selecting two connection elements.

In an embodiment, the method also comprises the step of taking all or some of the particulate material out

of the space defined by the container.

In an embodiment, the step of taking all or some of the particulate material out comprises a reverse of the inputting step. In an embodiment, the step of taking all or some of the particulate material out comprises reversing the pump which inputted the material .

In an embodiment, the method also comprises the step of allowing the particulate material to settle within the container.

This step enables clean water to separate from the particulate matter. This step also creates a substantially uniform thickness of particulate material within the container, which stretches the sides of the container. This is turn will pull the top sheet of the container down on top of the settled particulate material inside, creating a tight outer layer surrounding the particulate material .

According to a third aspect of the present invention, there is provided a method for reinforcing or constructing a navigation channel in a waterway, the method comprising the steps of: positioning a first storage container according to the first aspect of the present invention in the waterway at or above a location which is or will be a side of the channel; dredging particulate material from or to form the channel; and inputting at least some of the dredged particulate material into the space defined by the first container.

The step of inputting at least some of the dredged material weighs the container down to hold it and the material it contains at the side of the channel, causing it to sink. The weighed down container thus forms a part of the side of the channel.

In an embodiment, the method further comprises

the steps of positioning a second storage container according to the first aspect of the present invention in the waterway at or above a location which is or will be a side of the channel and inputting at least some of the dredged particulate material into the space defined by the second container.

The step of inputting dredged material into the second container may or may not occur concurrently with the step of inputting dredged material into the first container.

In another embodiment, the step of inputting dredged material into the second container occurs after the step of inputting dredged material into the first container has been completed. The second container may or may not be positioned, at least in part, above the first container. If it is, then when filled with particulate material, the second container is weighed down, sunk and held, at least in part, on top of the first container. In an embodiment, the steps of positioning and inputting are repeated for third and further storage containers according to the first aspect of the invention.

Brief Description of the Drawing Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawing, in which:

Figure 1 is a perspective view of a storage container for holding particulate material in water according to an embodiment of the present invention.

Detailed Description of Embodiments

Referring to Figure 1, a storage container 10 for holding particulate material in a body of water is shown. The storage container 10 is formed from a plastics material which is impervious to water and defines a space in which the particulate material may be held. The

particulate material is typically waste material, such as waste material from dredging, which may also be referred to as "marine mud", "bay mud", or "dredging spoils". Of course, the container 10 could be used for holding other particulate materials such as sand, non-toxic industrial sludge or toxic particulate material, for example.

A significant advantage of the storage container 10 according to embodiments of the invention is that it allows for ready disposal of dredging waste material with minimal environmental impacts. The dredging waste material can be pumped into the container 10 as dredging occurs or from storage on a dredger and held in the space of the container in water, specifically in the waterway in which dredging is occurring. This overcomes the problem of the waste material drying out and forming H 2 SO 4 when dumped on land. Importantly, it also avoids the problem of increased turbidity occurring in the water where the waste material is disposed because it is generally confined to the space defined in the container. In addition, because the material from which the container 10 is formed is impervious to water, any toxic material within the particulate material cannot leach out with water from the container 10.

The container 10 is arranged to sink to the floor of the body of water upon receipt therein of a sufficient amount of particulate material. This advantageously enables the container 10 to provide stable storage of particulate material and thereby prevent the particulate material or the container 10 from being moved significantly by any flow of the body water. As will be discussed further on, this enables the containers 10, when holding particulate material, to be utilised in applications to reinforce underwater floors and walls.

The container 10 is expandable so as to enable the space defined by the container, in which the particulate material is held, to increase. This expansion generally occurs under the action of inputting the

particulate material to the space. The container 10 is formed from at least one sheet, which is stretchable to provide for the expansion of the container 10.

In the embodiment shown in Figure 1, the container 10 is formed from a top sheet 11, a bottom sheet 12 and four middle sheets 13. The middle sheets 13 space apart the top and bottom sheets 11, 12 and define the space therebetween. The sheets 11, 12, 13 are joined by fusion or heat-welding. Thus, the container 10 has an approximately rectangular prism shape. The shape of the container 10, however, may be distorted by the amount of particulate material held in the container 10. The container may also alternatively be provided with a cylindrical shape or any other shape as required. The sheets 11, 12, 13 are generally all of a thickness of 0.5 to 10 mm, preferably 1.0 to 4.0 mm, more preferably 1.5 to 3.5 mm.

However, in another embodiment not shown in Figure 1, the container is formed from one sheet. In this embodiment, the sheet is folded to define two portions of the sheet, the two portions being joined where they overlap to define the space in which the particulate material may be held. The two portions are joined at or near the edges of where they overlap by fusion or heat- welding. The two portions may or may not be identical to one another, ie. the sheet is or is not folded in half. In a further embodiment not shown in Figure 1, the container is formed from two sheets. In this embodiment, the sheets are positioned one on top of the other and joined where they overlap to define the space in which the particulate material may be held. The two portions are joined at or near the edges of where they overlap by fusion or heat-welding.

Referring again to Figure 1, the container 10 comprises an inlet 15 for inputting the particulate material to the space. The inlet 15 is formed through the top sheet 11 of the container 10 (towards the centre of

the top sheet 11 for more even distribution of the particulate material within the space) and comprises a tube 16 projecting from the top sheet 11 of the container 10. As shown in Figure 1, the tube 16 connects to a pipe 17, such as from a dredger, to enable particulate material to be pumped into the space of the container 10 through the inlet 15. In other embodiments, the container 10 may- comprise multiple inlets. The multiple inlets may or may not be used simultaneously. The tube 16 defines a sealable portion of the container 10 for sealing the inlet 15 closed after the particulate material has been received in the space by crimping or clamping the inlet tube 16, for example.

However, the space defined by the container 10 shown in Figure 1 is never completely sealed closed because the container 10 also comprises a plurality of vents 20 for releasing gas from the space. The gas is typically methane gas, which is a by-product of the breakdown of organic matter in the particulate material (in particular where the particulate material is waste material from dredging or any other waste material containing organic matter) . Each vent 20 comprises an aperture in the top sheet 11 of the container 10. The vents 20 may or may not be identical to one another. The container 10 also comprises a valve in the form of a flap 21 for each vent. The valves reduce the loss of the particulate material held in the space defined by the container 10 whilst still allowing the gas to be released through the vents . The valves in the form of flaps 21 also enable clean settled water that has separated from the particulate material to slowly discharge from the container 10. This settling process may be aided by the additional of a flocculant to the container 10 to flocculate the colloids therein. It is also noted that as the particulate material settles, over time it will reach a substantially uniform thickness and stretch the sides of the container 10. This is turn will

pull the top sheet 11 of the container 10 down on top of the settled particulate material inside, creating a tight outer layer surrounding the particulate material.

Each flap 21 has a surface area which is greater than the cross-sectional area of its respective vent 20. The flaps 21 may or may not be identical to one another. Although not shown in Figure 1, some of the flaps may be joined together to provide a single flap for a number of vents. It is noted that although Figure 1 shows the valves in the form of flaps 21, the valves may be any other suitable valve mechanism which allows release of gas through the vents 20 but with retention of the particulate material. For example, the valves may be bubble valves. In an embodiment not shown in Figure 1, the inlet 15 may comprise one of the vents. Correspondingly, the sealing mechanism comprises the flap for covering that vent.

Each flap 21 has an attachment portion 22 which is joined to an outer surface of the top sheet 11 of the container 10. The attachment portion 22 of each flap 21 is joined to the outer surface of the top sheet 11 by fusion or heat-welding. In the embodiment shown in Figure 1, the attachment portion 22 comprises one side of each flap. Each flap 21 is rotatable about its attachment portion 22 between a covering position and an open position. In the covering position, each flap 21 is covering its respective vent 20. In the open position, each flap 21 is exposing its respective vent 20. The attachment portion 22 of each flap 21 is located in the same direction from its respective vent 20. This enables the container 10, in use, to be orientated whereby a substantial component of a flow of water past the container 10 biases each flap 21 towards its covering position where it is covering its respective vent 20. This bias acts against the flaps 21 undesirably "lifting" away towards its open position and opening the vents 20 due to

the flow of water past the container 10, which might result in undue loss of particulate material from the space in the container 10. However, the flaps 21 are still able to be moved towards their open position by any gas as it escapes from the space through the vents 20.

In a variation not shown in Figure 1, each flap may be joined to the outer surface of the top sheet of the container by two attachment portions . The two attachment portions may be separate from or adjoining one another. The two attachment portions may also be at an angle to one another which is greater or less than 180° or may be on opposing sides of each flap. Generally, however, the two attachment portions are arranged to restrict the movement of each flap away from the vent. This acts against the flaps undesirably "lifting" away and opening the vents due to the flow of water past the container.

In a further variation, the container 10 comprises at least one group of three connecting elements for each flap, arranged in a triangular formation for selectively connecting each flap to two of the three connecting elements. The at least one group of connecting elements are located on an outer surface of the container, preferably on the outer surface of a top sheet of the container. The selection of the connecting elements is generally dependent on the direction of flow of water past the container. Each flap can be connected to the appropriate connecting elements whereby a substantial component of the flow of water past the container biases each flap towards its covering position where it is covering its respective vent.

The connecting elements may comprise clips with the flaps consequently having suitable elements to be received in the clips . The connecting elements enable the flap to be connected in four different orientations which are preferably at right angles to one another.

Each vent may then be formed in an appropriate location after the connecting elements to which its

respective flap is to be connected have been selected by- piercing the outer surface of the container.

The container 10 may also comprise at least one flow indicator for indicating the direction of flow of water past the container. In the above variation, a flow indicator is connected to the container 10 in close proximity to each group of connecting elements. Generally each flow indicator comprises a strip of material.

In another variation, the container may not have any vents (and hence would not have any valves) . There are no apertures through the container to the space other than the inlet. Thus, when the inlet is sealed closed by the sealing mechanism, the space is also sealed closed.

Referring again to Figure 1, the container 10 also comprises at least one, preferably eight (only four are shown) , towing anchors 25 for connecting to a ship to move the container 10 through the water. Generally, four towing anchors 25 are used to connect the container 10 to the ship for towing. The towing anchor (s) 25 is connected to an outer surface of the container 10, preferably to the outer surface of the top and bottom sheets 11, 12 of the container 10. The at least one towing anchor 25 comprises a solid ring (approximately 50 mm thick) which is fusion or heat welded to the outer surface of the container 10. As discussed above, at least a portion of the container 10 is formed from a stretchable material. In the embodiment shown in Figure 1, the top sheet 11, bottom sheet 12 and middle sheets 13 are all formed from such a material. The stretchable material is preferably stretchable at least 200%, more preferably at least 500%, even more preferably at least 800%.

The material from which the sheets 11, 12, 13 is preferably high density polyethylene (HDPE) or polyvinyl chloride (PVC) . It is noted that choice of plastic material may affect the stretchability of the sheets 11,

12, 13 as well as the required thickness of the sheets 11, 12, 13.

The sheets 11, 12, 13 of the container 10 may also be formed from a biodegradable material. In this embodiment, the particulate material is only temporarily held in the container 10 as the container will eventually break down.

It is noted that the flaps 21 may be formed from the same material as the sheets 11, 12, 13. The at least one towing anchor 25 is also formed from the same or similar material as the sheets 11, 12, 13, for example HDPE or PVC.

In a variation not shown in Figure 1, the container 10 also comprises perforated tubing for inflating and deflating the container 10 with air, preferably located at the sides of the container 10 around the perimeter of the space defined by the container 10. It may be necessary to inflate the container 10, at least partially, for floatation of the container 10 when moving, orientating or re-orientating it in the water. Also, when particulate material is inputted to the space defined by the container, in particular to the centre of the space, the centre of the container 10 sinks first under the weight of the particulate material. This can cause the air in the container 10 (whether deliberately inflated or not) to rise into the sides of the container. In some situations, this air may be trapped at the sides, leaving a region of the container 10 which is buoyant in water. In these cases, the trapped air can be removed by sucking it out through the perforated tubing at the sides of the container. This in turn will cause the particulate material to spread out towards the sides of the container 10.

The perforated tubing comprises HDPE or PVC tubing (approximately 50mm in diameter) which is heat or fusion welded to an inner surface of the container 10, in one embodiment to the inner surface of the middle sheets

13. The perforated tubing may in one embodiment be located on the middle sheets 13 at a mid-point between the top and

bottom sheets 11, 12, preferably towards the top sheet 11 towards which any trapped air is likely to rise.

Description will now be provided on how the storage container 10 may be used: In particular, the storage container 10 is used to hold particulate material in a body of water. A method of using the container 10 as such comprises the steps of positioning the container 10 in the body of water and inputting the particulate material to the space defined by the container 10. These steps may be conducted in no particular order, although preferably the step of positioning the container 10 in the water occurs first. Where the container 10 is to be used to hold dredging waste material, the step of positioning the container 10 is carried out by connecting the container 10 via the or at least one of the towing anchors 25 to a ship (usually the dredge) and towing the container 10 to a desired position. The container 10 is preferably formed of a material that enables it to float in the water when it contains no particulate material. Alternatively, where the container 10 is not so formed, the container 10 could be partially filled with air to enable it to float in the water. The inlet 15 of the container 10 is connected to the pipe 17 of the dredge in preparation for the step of inputting dredging waste material into the container 10. Inputting the dredging waste material, by pumping it as a slurry using a pump, into the container 10 space may occur concurrent with the dredging process or may occur once the dredging process has been completed. In this case, the waste material is pumped from a holding vessel on the dredge to the container 10.

The waste material is pumped into the space defined by the container 10 such that it is sprayed towards all sides of the space. This is to act against the localised build-up of particulate material in the space, which could significantly reduce the volume of material which can be inputted to the space. As the space of the

container 10 fills with waste material it begins to sink to the floor of the body of water. The space may also increase in volume as the inputted waste material stretches and expands the container 10. Once the step of inputting the waste material has been completed, the pipe 17 is disconnected from the inlet 15. The inlet tube 16, before or after disconnecting the pipe 17, is then sealed to close the inlet 15 by crimping or clamping the inlet tube 16. The inlet 15 may be alternatively closed by obstructing the inlet 15 in any other suitable way.

An additional step in this method may involve orientating the container 10 so that a substantial component of a flow of water past the container 10 biases each flap 21 towards its covering position where it is covering its respective vent 20.

The method may also comprise the step of taking all or some of the particulate material out of the space defined by the container 10. This might be carried out where for example, product material was temporarily stored in the space of the container 10. This step typically occurs as a reverse of the step of inputting the particulate material, preferably by reversing the pump which inputted the material and sucking the material out of the space.

The storage container 10 or a plurality of the storage containers 10 may also be used in a method for reinforcing or constructing a navigation channel in a waterway. This method comprises the steps of positioning a first storage container according to an embodiment of the present invention (such as the storage container 10 as shown in Figure 1) in the waterway at or above a location which is or will be a side of the channel, dredging particulate material from or to form the channel, and inputting at least some of the dredged particulate material into the space defined by the first container.

The particulate material inputted into the space

of the first container weighs the container down, causing it to sink and to hold the container and the material it contains at the side of the channel. The weighed down container thus forms a part of the side of the channel. Advantageously, the weight of the first container and the particulate material inside acts against the container (and hence at least a part of the sides of the channel) from being moved by water flowing past. Furthermore, because the particulate material is held within the first container, it is not significantly eroded by the flow of water. This means that use of the storage container 10 in this method can help alleviate the problem that most navigation channels require constant dredging to maintain them. The method may further comprise the steps of positioning a second storage container according to an embodiment of the present invention (similar to the first storage container) in the waterway at or above a location which is or will be a side of the channel and inputting at least some of the dredged particulate material into the second container.

Inputting particulate material into the second container may or may not occur concurrently with inputting dredged material into the first container. Alternatively, it occurs after inputting dredged material into the first container has been completed.

The second container may or may not be positioned, at least in part, above the first container. If it is, then when filled with particulate material, the second container is weighed down, sunk and held, at least in part, on top of the first container.

The method may also comprise repeated steps as described above of positioning and inputting for third and further storage containers similar to the first and second storage containers.

In the preceding description of the invention and in the claims which follow, except where the context

requires otherwise due to express language or necessary implication, the word ^comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, ie. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.