BACKGROUND OF THE INVENTION As environmental awareness has increased in recent times individuals, companies and government authorities have begun looking at various ways of reducing waste.

Domestic waste in particular has a high quantity of organic material which, if treated correctly, can provide useful fertiliser or compost for domestic or agricultural use.

In this context, worm farming has proved a particularly useful and successful means of treating organic material. Generally the worm farm comprises some form of receptacle that is filled with soil and/or organic matter and worms. The worm farm is kept moist to encourage movement and breeding of the worms. The worms digest the organic matter and eject their castings into the bed. This produces a top soil/compost mixture which is high in nutrients and ideal for garden beds, potting mix etc.

Conventional worm farms, however, have some serious drawbacks.

Most conventional worm farms comprise one or more trays or beds. The bed is normally substantially filled with organic material and top soil with some form of drainage system underneath to provide for removal of excess moisture.

Australian patent application no 58295/94 for example discloses a worm farm which comprises a series of stackable containers. Apart from the lowermost container which has a solid base and is provided with a liquid run-off tap, each container has a perforated base to allow worms and fluid to pass therethrough. The stacks are rotated with the next to lowermost stack regularly being transferred to the top for dosing with fresh organic matter.

Such arrangements have relatively low capacity because of the limitations associated with the design namely that the trays must be periodically"shuffled". This regular movement of the trays also causes disturbance of the life cycle of the worms. Further, since the bottom tray is usually filled with liquid, the worms may migrate through all the trays and drown in the lowermost tray.

It is an object of the present invention to overcome or ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.

DISCLOSURE OF THE INVENTION In a first aspect, the present invention comprises an apparatus for treating organic matter and/or breeding worms comprising a receptacle adapted to receive organic matter and worms therein, at least a portion of one or more walls of the receptacle being adapted to allow passage of castings and/or fluid therethrough but prevent passage of substantial quantities of organic matter or worms.

Preferably the means for allowing passage of worm castings and/or fluid is a plurality of apertures in at least one of the walls or floor of the receptacle. More preferably the walls or floor of the apparatus are formed from a mesh.

The walls of the apparatus may be tilted outwardly and/or the receptacle may be substantially triangular in cross-section. Alternatively the receptacle may be formed with an inverted conical shape.

In a particularly preferred embodiment, the receptacle suspends the organic matter, soil and worms contained therein above the ground.

In another embodiment, the lowermost portion of the receptacle is formed with the means for trapping and transporting fluid away from the underside of the apparatus.

It is also preferred that said apparatus includes a means for collecting worm castings ejected from said receptacle. Preferably this means for collecting the worm castings comprises slides or funnel means directly adjacent the outer surface of the receptacle for directing said worm castings to fall into a collection bin directly below the receptacle.

In another broad aspect, the present invention provides an apparatus for treating organic matter and/or breeding worms, the apparatus comprising a receptacle adapted to be substantially filled with organic matter and a plurality of worms wherein the interior of the receptacle is substantially free of obstruction such that the worms are able to move substantially unhindered within the volume of the receptacle.

Unless the context clearly requires otherwise, throughout the description and the claims, the words'comprise','comprising', and the like are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of"including, but not limited to".

BRIEF DESCRIPTION OF THE DRAWINGS In order that the nature of the present invention may be more clearly understood it will now be described, by way of example only, with reference to the accompanying drawings in which: Figs. 1 and 2 are end and side elevational views respectively of a preferred embodiment of the apparatus for treating organic matter and/or breeding worms according to the present invention; and Fig. 3 is a cross-sectional view A-A through the apparatus of Figs. 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION As shown in figures 1 and 2, the apparatus comprises a receptacle or bin 100 supported by a frame 200.

The body of the receptacle 100 is formed by side walls 120,130 joined by end walls 140,150. Preferably side walls 120,130 and/or end walls 140,150 converge downwardly to meet at lower portion 160. This inclined design of the side walls is not essential however and the receptacle 100 could equally be formed with vertical side and end walls connected at their lower edges by a floor. The inclined wall arrangement shown in the drawings simply assists in recovery of the worm castings as will be discussed below. The receptacle may further include an upper closure member 110 which acts as a lid for the receptacle. The lid 110 may be hinged to the body of the receptacle as shown in Fig. 1, or alternatively it may be removable from the body of the receptacle.

In one form of the invention, one or more of the end walls 140,150 and/or side walls 120,130 may be adjustable in position so as to enable the capacity of the receptacle to be varied. For example, one or both of the end walls 140,150 may be positionable at a variety of positions within the frame 200 so as to vary the effective length of the receptacle available for organic matter. In this way, the capacity of the receptacle can be varied.

In use, the receptacle is firstly filled with soil and/or organic matter 50 (Fig. 3) which provides an excellent bedding and breeding ground for worms. The receptacle is also dosed with a suitable number of worms. It is not necessary to provide a large amount of worms at the initial dose since the inventive apparatus also provides an ideal environment for breeding the worms as well as treating the organic matter in the receptacle.

After the worms are added, the receptacle should be lightly watered. Worms generally prefer a moist environment of around 60-70% moisture content.

The worms feed on the organic material in the receptacle. Their castings are ejected into the receptacle. As the volume of worm castings in the receptacle increases, the castings are pushed out through the side walls and/or end walls from where they fall to the

ground. Fluid may also pass through apertures formed in the side walls 120,130 and end walls 140,150. Preferably the side and end walls are constructed from mesh grille.

Collection means 170 may be provided directly underneath the receptacle for catching the worm castings which fall to the ground after passing through side walls 120, 130 or end walls 140,150.

As mentioned above, the side 120,130 and end walls 140,150 of the receptacle are preferably formed from mesh. Surprisingly, the applicant has found that it is not necessary to use a fine grade mesh to retain the worms within the receptacle. Course mesh with gaps up to several centimetres eg up to 10-20 centimetres may be used without excessive loss of organic matter or worms within the receptacle.

It is believed that a worm farm according to the present invention relies on the worms sensing the difference between the conditions within and outside of the receptacle. As a worm moves about the organic matter within the receptacle, it may reach the periphery of the receptacle and one end may pass through the mesh. The remainder of the worm remains encased within the soil/organic matter in the receptacle. However, this very rarely, if ever, results in the worm falling to the ground. A number of explanations for this phenomenon have been put forward, including the worm's sensitivity to light changes, and a sense of gravity.

This is in contrast to conventional worm farms which have an apertured floor. When the worm reaches the apertured floor it can continue migrating through the apertures, along the underside and the sides of the trays and frequently ends up drowned in the liquid container normally resting below. With the present invention, on the other hand, when the worm reaches the edge of the receptacle and exposes one end, the remainder of the worm is

still firmly encased within the receptacle and will not automatically fall out of the organic matter.

Apart from the fact that the present invention reduces the quantity of worm lost, it has several other advantages including that it is unnecessary to separate the worms from the worm castings. With conventional worm farms, it is the worm castings, organic matter and worms all remain intermixed. To use the worm castings it is then necessary to remove the worms therefrom. With the present invention this is not necessary since the worm casting are ejected from the receptacle thereby separating them from the worms for collection.

Of course, if desired the receptacle may use much finer mesh, eg chicken wire. This will decrease the possibility of worms falling out of the receptacle but will also decrease the ease with which worm castings are ejected therefrom.

The lowermost portion 160 of the receptacle is preferably formed as a drainage means. Most preferably this drainage means has a channel 165 or drain at its lowermost portion which directs any fluid away from a position directly underneath the receptacle or at least, as shown in Fig. 2, to a position or receptacle 167 spaced from the collection means 170. In this way, any worms which do manage to pass through the side or end walls 120-150 will fall into the casting collection means 170 rather than into a pool of liquid and drown as would occur in conventional worm farms.

In the embodiment shown, in addition to drainage channel 165 lower most portion 160 includes an absorbent means 168, eg. foam rubber. The upper surface of this absorbent foam rubber is preferably formed with downwardly sloping sides. The areas directly above the absorbent foam rubber are shown in the drawing as empty for illustration purposes only. Normally this area would be filled with the organic matter, soil and worms

from the receptacle. The downwardly sloping sides of the absorbent foam rubber are useful for several purposes. Firstly they force the organic matter, worm castings etc to order the exterior sides on 20,130 of the receptacle. Further, if the absorbent material 168 was formed with a horizontal upper surface it would be compressed by the weight of the organic material/worms above it thereby reducing its ability to absorb moisture.

The foam rubber 168 absorbs moisture fall through the material in the receptacle.

Further, with the inventive tapered sides 120,130 of the receptacle 100 any moisture being forced out towards these sides will run down the exterior of the receptacle and be absorbed at the lower end by foam rubber 168. The moisture in the foam rubber then fall towards channel 165 where, as discussed above, it is directed away to a position or receptacle 167 at the site of the collection means 170.

As discussed above, most conventional apparatus comprise a series of trays with grates or holes through each floor. These sit on a lowermost tray which collects fluid. The worms can pass through the grate of each stack making their way down through the last grate and can continue crawling downwards along the sides of the trays until they reach the fluid and drown. A substantial number of worms can be lost in this manner. The present invention avoids these difficulties by allowing the fluid to drain to the lowermost portion of the receptacle from where it is transported away from directly underneath the receptacle.

To continue to provide a suitable environment and feed for the worms in the receptacle all that is required is to add fresh organic material to the top of the receptacle and keep the material in the receptacle moist by regular light watering.

In a preferred embodiment, the apparatus also include casting slides 220 adjacent the outer surface of walls 120-150. These slides act to guide or funnel the worm castings passing through walls 120-150 into the castings collection means 170. It is preferred that

these slides 220 are not perforated, however, to increase air circulation and reduce the weight to be supported by frame 200 the slides may be made from a lightweight material such as shade cloth as shown in Figs. 1 and 2.

Similarly, the lid 110 may be covered with shade cloth. A moisture permeable material 210 may be suspended from the lid, as shown in figure 3. This material 210 rests on the upper surface of the organic material/top soil in the receptacle when the lid is closed.

It acts to help retain the organic matter etc. in receptacle and also reduce evaporation of moisture. Hessian has proved particularly useful in this regard. Further, by providing shade cloth for hingeable lid 110, any rain etc passes through the hingeable lid to be absorbed by the hessian material 210 which assists in maintaining an appropriate moisture level in the organic matter for the worms.

By providing walls which allow worm castings and fluid to pass therethrough but retain the worm themselves and the organic matter in the receptacle, it is unnecessary to continually shuffle or rotate the organic matter in the receptacle. Unlike the conventional "multi tray"worm farm there is no labour associated with movement of the organic matter in the receptacle. Such shuffling can disturb the breeding and life cycle of the worms, which is undesirable. With the present invention no shuffling of trays or rearranging of the organic matter is required.

Another advantage arising from the present invention is that due to the interior of the receptacle being substantially free of any obstruction the worms are free to move within the interior volume of the receptacle. This provides significant advantages over conventional mechanism since, unlike conventional worm farms, the life cycle of the worm is undisturbed. Indeed, the various areas within the receptacle of slightly different moisture, organic content, etc help to replicate nature and improve breeding of the worms.

With the present invention it is also possible to build much larger worm farms than previously proposed or constructed. Unlike the previous conventional tray systems which require continual rotation etc, once the receptacle 100 is filled with organic material and dosed with a number of worms, it is unnecessary to move trays or aerate the organic matter etc. This inventive design allows large receptacles to be built for treating organic material.

As the worm castings are shed from the receptacle and the level of organic material drops, additional organic material my simply be added to the top by opening lid 110.

As shown in Fig. 3, in order to minimise compaction of the organic material/top soil in the receptacle supporting beds 250 may be provided within the interior of the receptacle.

These supporting beds may once again be formed from mesh. Preferably the mesh is quite course eg spacings up to 15-20 centimetres (6-8 inches). Angled separators 260 may also be provided on the support beds. These angled separators direct the worm castings toward the sides of the receptacle from where they pass through the walls 120-150 for eventual collection in casting collection boxes 170.

In a further development of the invention, the frame 200 and/or receptacle 100 may be of a demountable design, thus enabling the apparatus to be assembled in situ. The frame and receptacle may be produced from any suitable material such as steel, plastic etc. In one preferred embodiment the frame 200 is formed from hollow section steel tubing or the like. It is particularly advantageous that the receptacle is produced from galvanised or stainless steel mesh. This is not only extremely strong but reduces the likelihood of corrosion which may occur due to the high moisture content of the organic material in the receptacle. As mentioned above the casting slides can be produced from any durable material such as plastic sheeting etc however perforated material such as shade cloth is particularly suitable since it is light and allows moisture and air to pass therethrough. As

will be known to persons skilled in art, it is important that the material in the organic bed does note overheat since this may kill the worms or cause unnecessary side effects such as methane production etc.

It can be seen from the above that the apparatus of the present invention provides significant advantages over the prior art. It will be understood by persons skilled in the art that the embodiments shown are illustrative and not restrictive, and that the apparatus may be embodied in other forms without departing from the spirit or scope of the present invention.