WO1993010060A1

WO1993010060A1 - Compost bins

Info

Publication number: WO1993010060A1
Application number: PCT/GB1992/002092
Authority: WO
Inventors: Clive Winstanley Roberts
Original assignee: Original Organics Limited
Priority date: 1991-11-19
Filing date: 1992-11-11
Publication date: 1993-05-27
Also published as: GB2276158A; AU2924592A; GB2276158B; GB9124509D0; GB9410066D0

Abstract

A compost maker comprises a container (1) having a perforated inner base (2) defining a sump region (3), having a tap (4) for removing liquid formed during compost making, and a compost forming regions closed by a lid (5) for the container. Compost is made by placing worms, particularly of the species Eisenia Foetida and/or Eisenia Andrei, and compost forming organic material in the compost forming region. The worms feed on the organic material and generate compost. The compost maker may include a worm collector comprising a container having a perforated base and a container, which in use is used to continue compost making so as to attract the worms into the worms collector enabling the main bin to be emptied and compost making to be restarted using the worms from the worm collector.

Description

Compost Bins

This invention relates to compost bins and to methods of making compost. In particular it relates to compost bins and methods of making compost in which worms feed on organic material, especially organic domestic refuse such as vegetable matter, whether as food waste or manufactured products such as paper or card.

The role of worms in the breakdown of organic material into humus in the soil has long been recognised. This invention seeks to exploit this natural behaviour and effect to convert organic waste, particularly vegetable organic waste into useful nutrient rich compost.

Thus, a compost bin comprises a container having substantially opaque walls and closed lower end, the container having spaced above the closed lower end a perforated inner base, defining a sump region between the inner base and closed lower end and a compost forming region within the container above the inner base; a tap capable of draining liquid from the sump region; and a substantially opaque lid capable of closing the upper end of the container but removable therefrom.

In use, compost forming material and/or previously made compost is placed on the inner base together with worms, either added to the material or, as is possible with previously made compost, in the compost itself, and fresh compost forming material is added. The perforations in the inner base are large enough to allow adequate drainage of the compost but not so large as to let compost fall into the sump. The worms consume the compost forming material converting it into compost. When the compost bin is full, it can be emptied and reused. During compost formation, water is released which percolates through the lower layers of compost and accumulates in the sump region. This water typically forms an aqueous mix containing dissolved and/or dispersed nutrients and is of value as a liquid fertilizer or plant feed. It can be withdrawn as desired from the sump region through the tap. As well as being itself valuable, the aqueous mix is desirably withdrawn periodically to prevent the liquid level rising above the inner base and waterlogging the lower layers of compost.

The worms used can be any type of composting earth worm, but are desirably of the so-called manure worm type (a description of natural habitat rather than species). In particular, we have obtained good results with worms of the species Eisenia foetida, also known as brandling or 'tiger' worms, and Eisenia Andrei, also known as the red worm. In starting the operation of the compost bin it is useful for the worms to be provided as mature worms, for example in compost in a suitable container. Worm eggs can also be included to further increase the worm population during the start up period. The composting function can be started by placing compost forming material on the inner base and adding the worms. Further compost forming material can then be added to cover the worms. It can take several days for the composting activity of the worms to increase to a steady rate. A container of about 100 litres capacity can sustain a worm population sufficiently large to compost the vegetable organic rubbish from a typical family household. This level of activity is typically reached after about 3 weeks operation.

in steady use a compost maker of about 100 litres capacity will compost organic matter at a rate adequate to consume the vegetable organic matter of a typical family household for about 3 months. During this time the worms convert the organic matter to compost, slowly filling the bin. The compost made occupies a much smaller volume than the original organic matter so the effective capacity of the bin is larger than its mere volume. The water generated as a by-product in the compost making process drains through the compost as described above. As the organic matter is consumed the bin slowly fills with compost. When the bin is as full as is desired, addition of further organic matter is stopped and the compost maker left for several days to complete the composting of the organic matter in the bin. The compost can then be emptied from the bin and used in growing plants. The nutrient value of this compost is typically much higher than for conventional composts so it will usually be used mixed with soil, sand etc to dilute it for use. The composting worms are top feeders and tend to concentrate near the surface of the compost and/or organic matter in the bin. They also tend to be photophobic so, in use, the bin will be kept closed with the substantially opaque lid. The lid desirably has ventilation holes but these will be small enough to prevent access to undesired insects such as house flies or bluebottles, which would find the organic material attractive as a food source and/or for egg laying (resulting in maggot infestation). The ventilation holes may be backed with fine gauze, if desired, as a further precaution against insect entry.

When the bin is full and the compost removed from it, the worms will typically mainly be in the top layer of compost, typically about 15cm deep. To assist re-starting the compost maker it is useful to set aside this top layer, remove the remaining compost for use and re-use the erstwhile top layer as the starting compost on the inner base when re-starting compost making. To make this operation more easy to do the invention includes, as a specific feature, a worm collector comprising a body forming a container, which fits within the main compost bin container, having a perforated base, with holes large enough to allow worms through but small enough to retain compost within the worm collector, and a closure, particularly taking the form of a lid, preferably also having ventilation holes. In use, when the main bin is nearly full, the worm collector is placed in the main bin and compost forming material is placed in the collector to start forming compost within the collector. Once a layer of compost say 15cm deep is formed in the worm collector, most of the worms will be in the collector which can be easily lifted out of the main bin, the main bin emptied and the contents of the worm collector emptied into the main bin, on the inner base to act as the basis for renewed compost making.

The invention includes a method of making compost in the compost maker of the invention by introducing compost forming organic material into the compost maker in which there are active composting worms, particularly Eisenia foetida and/or Eisenia Andrei.

The invention includes a kit of parts for a compost maker comprising:

a container bin having substantially opaque walls and a hole in one side wall near the base; a substantially opaque lid for the container bin, preferably having ventilation holes; a tap for closing the hole in the side wall; a perforated inner base for the container; and composting worms and/or eggs thereof.

A preferred kit further includes a worm collector comprising a body forming a container fitting within the container bin and having a perforated base and provided with a lid or other closure.

In the accompanying drawing Figure 1 is a diagrammatic cross- section of a compost maker in operation and Figure 2 is a diagrammatic cross-section of the upper part of a compost maker including a removable worm collector.

In the compost maker illustrated in Figure 1, the main body(l) is provided by a bin, typically made of thermoplastic material such as low density polyethylene. The main body(l) typically has a volume of 20 to 200 litres, depending on use requirements and is generally rectangular or circular in cross section, but if rectangular the corners will usually be rounded for good impact resistance, particularly as the main body(l) will typically be made by injection or rotary moulding. The main body(l) is provided with an inner base(2) which is perforated. The inner base(2) is positioned at a convenient height, typically about 20cm above the inside of the base of the main body, and, together with the main body below it defines a sump region(3). A tap(4) is provided in the wall of the main body(l), typically about 10cm above the base of the main body, to provide a means of draining liquid from the sump region(3). The compost maker is further provided with a lid(5), typically of thermoplastic or rubber material, which will usually be made well fitting to exclude vermin and undesired insects from, and minimise the light admitted to the inside of the compost maker. As illustrated, the lid(5) is provided with ventilation holes(6) sufficiently small to exclude undesired insects. The ventilation holes may be backed with fine gauze, if desired, as a further precaution against insect entry.

In operation of the compost maker illustrated in Figure 1, compost forming organic matter is placed in the bin where worms in the compost below will consume the organic matter and convert it into compost. As illustrated, freshly added organic matter(7) lies on compost (8). The top layer(9) of the compost, typically about 15cm deep, is the zone in which the worms are concentrated and most active. In the composting process, typical compost forming organic matter releases significant amounts of water which drain through the compost into the sump region from which it can be removed from the compost maker through tap(4). The water which drains through the compost dissolves or suspends nutrients from the organic material and/or compost to give a solution (or suspension) of value as a liquid fertiliser for plants. It is desirable to avoid the water level rising up as far as the inner base(2) as this may lead to the compost becoming waterlogged. When the level of compost in the compost maker is not high, such waterlogging may drown the worms thus stopping compost formation.

The compost maker can be started, particularly the first time, by placing a thin layer of compost forming organic material, preferably relatively dry material such as shredded paper, on the inner base(2) putting worms and/or worm eggs on the paper and adding a further thin layer of compost forming organic material, particularly domestic vegetable refuse, and leaving the compost maker for a few days to allow the worms to become fully active. Once the worms are active organic material can be added, preferably in relatively small amounts over the first week or so. As compost forming material is added and consumed, compost is formed and gradually fills the bin. The aqueous material that drains into the sump region is desirably removed periodically to avoid the level rising above the inner base and waterlogging the lower layer of compost.

The worms tend to live mainly in the upper layer of compost and the layer of compost forming material on top. Although the worms live in the upper layer(s) of compost/compost forming material, they tend to be, and Eisenia foetida and Eisenia Andrei are, photophobic, so the lid(5) is best put in place, apart from loading compost forming material, so as to avoid driving the worms deep into the compost(δ) and away from compost forming material(7). When the compost bin is full of compost, and the organic compost forming material composted, the worms can be removed by scooping out the top layer of compost, say to about 15cm deep, separately emptying the bin of compost and using the previous top layer as starter material for the next operating cycle. To assist this, a worm collector can be used to hold the worm rich top layer in the final stages of the operating cycle. Figure 2 illustrates such a worm collector and its operation. The compost bin(l) is nearly filled (in the Figure the effective 'headroom' inside the bin is exaggerated for clarity of illustration) with compost(8) and a worm collector is in the bin(l) holding the top layer of compost. As illustrated, the worm collector comprises a body(lθ) fitting within the bin(l) and typically about 15cm deep having a perforated base(ll). The holes in base(ll) are large enough to allow worms from the compost(8) to compost forming material put in the worm collector. As illustrated, the worm collector has the worm rich top layer of compost(12) within it and has a ventilated lid on top. The lid serves to reduce the effect of illumination within the compost bin, which might otherwise drive the worms back into the compost(8) below the worm collector.

When emptying the bin, the worm collector can be lifted out more easily and stored, prior to use in re-starting compost making, more readily than a 'loose' top layer of compost.

Claims

1 A compost bin comprising a container having substantially opaque walls and closed lower end, the container having spaced above the closed lower end a perforated inner base, defining a sump region between the inner base and the closed lower end and a compost forming region within the container above the inner base; a tap capable of draining liquid from the sump region; and a substantially opaque lid capable of closing the upper end of the container but removable therefrom.

A bin as claimed din claim 1 further including a worm collector comprising a body forming a container which fits within the compost bin container with holes large enough to allow worms through but small enough to retain compost within the worm collector, and a closure for the worm collector container.

A kit of parts for a compost maker comprising:

a container bin. having substantially opaque walls and a hole in one side near the base;

a substantially opaque lid for the container bin;

a tap for closing the hole in the side wall;

a perforated inner base for the container; and

composting worms and/or eggs therefor.

A kit as claimed in claim 3 further including a worm collector comprising a body forming a container which fits within the compost bin. container with holes large enough to allow worms through but small enough to retain compost within the worm collector, and a closure for the worm collector container.

A method of making compost comprising placing worms in the compost forming region of a compost bin as claimed in claim 1 and supplying compost forming organic material to the worms.

A method as claimed in claim 5 wherein the worms are of the species Eisenia Foetida and/or Eisenia Andrei.

A method as claimed in claim 5 wherein liquid is periodically removed from the sump region.

A method as claimed in claim 5 in which, when the compost bin is nearly full of compost, a worm collector as defined in claim 2 is placed in the bin; compost forming organic material is placed in the worm collector; and when, after a period of time worm rich compost is formed in the worm collector, the worm collector is removed from the bin; the main body of the compost bin is emptied and the contents of the worm collector emptied into the main compost bin to act as the base for renewed compost making.