AU2009202247A1 - Compost cover - Google Patents

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant (s): SIMON WALPOLE LEAKE and Patrick Soars Invention Title: COMPOST COVER The following statement is a full description of this invention, including the best method for performing it known to me/us: P72148.AU.2 PaSet Fling Application 2009-.65 doc (M) - 2 COMPOST COVER FIELD OF THE INVENTION 5 The present invention relates to compost covers for covering composting material in a composting structure so as to reduce the emission of odorous substances from the composting structure to atmosphere surrounding the composting structure and to methods of using the covers to 10 control composting and aspects of compost quality within the composting structure. In one form the present invention relates to a compost cover having different portions or sections for covering 15 composting structures. In one form, the present invention relates to a compost cover having a number of different layers to assist in composting of organic materials, including yard wastes or 20 similar green wastes amongst other materials, to control the emission of composting odours arising during composting of the green or yard wastes and/or as a result of composting occurring and to the use of the compost covers in an engineered composting system. 25 In another form the present invention relates to an engineered compost cover system for use in covering composting structures so as to both assist in the composting operations to provide more efficient composting 30 by allowing sufficient oxygen to flow through the composting mass to promote aerobic fermentation of the organic material in the compost mass so as to control the emission of malodorous substances produced as a result of N:\Melboume\Cases\Patent\720O0-72999\P72148.AU.2\Specis\P72148 AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 3 the degradation of organic materials during composting. The present invention finds particular application as a cover for a open composting system which allows moisture 5 and/or water vapour to condense within the interior of the cover so as to retain water internally within the cover for solubilising odour molecules within the water to condense the molecules thereby removing the odour molecule from the vapours or gases produced during composting of 10 the compost mass that are being vented to the atmosphere thereby providing an engineered composting system which reduces the emission of odours arising from composting processes being vented to atmosphere. 15 Although the present invention will be described with particular reference to one form of the compost cover and to one method of using the compost cover to improve the composting of materials and/or to reduce the emission of malodorous vapours, it is to be noted that the scope of 20 the present invention is not restricted to the described embodiment but rather the scope of the present invention is more extensive so as to include other forms and arrangements of the composting cover, other forms and arrangements of the composting system, other uses of the 25 various forms of the composting cover or systems and to other applications involving the use of the various forms of the composting covers described. BACKGROUND OF THE INVENTION 30 Composting is the degradation of organic materials by micro-organisms. The degradation of organic materials by micro-organisms can take place using a number of different N :Melboume\Cases\Patent\72000-72999\P72148 AU 2\Specis\P72148.AU 2 Specification tracked 2009-5-21.doc 5106109 - 4 processes such as aerobic degradation processes, anaerobic degradation processes, vermi-composting degradation processes or the like. Usually anaerobic processes result in the production of substances that have a malodorous 5 perception to humans. However, irrespective of the actual processes being used for composting the various types of organic materials that can be degraded by such processes, malodorous substances are produced during many of the composting operations despite the best efforts to 10 neutralise the odours. The malodorous substances produce odours which are perceived by humans as being unpleasant, aggravating, undesirable, nauseous, being a nuisance or similar. Clearly, it is desirable to reduce or minimise the amount of noxious odours produced by composting is organic materials, particularly if the site at which the composting of the organic wastes takes place is located in or near to a residential area or area of human activity. In the past, composting sites have had to be located well away from human activity in order to reduce the impact at 20 the malodorous materials on the nearby human population. However, the separation of human habitation and composting location has not always been feasible or economic since the additional cost of transportation of organic matter to the composting site for degradation and the transport of 25 useful products formed in the degradation reactions of composting from the compositing site to the sites where they are used adds to the overall cost of the recovered materials, sometimes to the extent that the waste materials are not recycled by composting but are discarded 30 in environmentally unacceptable ways, such as for example, being sent to land fill and the like. Thus, the production of offensive odours in composting processes is a major economic problem for the composting industry and N:\Melboume\Cases\Paten\72000-72999\P7214B AU 2\Specis\P72148 AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 5 results in conflict with planning and regulatory authorities, local communities and similar organisations that has generally resulted in reluctance on the part of local authorities in granting permits allowing composting s operations to take place in areas under their control and within their jurisdiction. This severely restricts where such operations can be located which often adds to the cost and complexity of the operations, and which has the disadvantage that a valuable resource is merely discarded 10 without any attempt to recycle the material or to form products which benefit the environment. Previous attempts at reducing the emission of malodorous substances from composting materials to allow more choice 15 and flexibility in selecting the site of the composting operation have not been entirely successful for one or more reasons as existing composting processes suffer from a variety of problems. 20 One of the problems associated with reducing the production of malodorous substances is that any attempt to depress the amount of odorous substances being produced also has an attendant effect of reducing the efficiency of the composting process so that the overall composting 25 process becomes less economically viable. This is because, on the one hand, if the supply of oxygen in the form of air is hindered this leads to anaerobic composting conditions. As aeration becomes limiting anaerobic or partially anaerobic processes occur within the compost. 30 Generally, badly aerated anaerobic conditions are usually associated with the production of the worst odours so that excluding air from the composting mass in an attempt to reduce the emissions of malodours often results in the N:\Melboum\Cases\Patent\72000-72999\P72148.AU.2\Spocis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 6 production of more and stronger malodours as anaerobic conditions are preferentially established within the composting mass. 5 On the other hand, if the supply of oxygen is unhindered in open composting situations, the expelled gases convey the malodorous substances away from the compost and they are released to atmosphere. Therefore, there is a need to reduce the production of odorous substances whilst 10 maintaining the efficiency of the composting process by controlling the amount of oxygen admitted to the composting mass to ensure that there is sufficient oxygen available for aerobic degradation of the organic waste materials so that the composting products can be produced 15 at an economically attractive cost to make the overall process economically viable or feasible whilst at the same time reducing the amount of malodorous materials resulting from the composting processes and methods and without adding complexity to the composting operation by requiring 20 the use of costly equipment, plant or installation, to neutralise the malodours or to remove the malodorous materials from the gases and vapours being emitted from the composting materials. 25 Accordingly, there is commercial value in developing a composting method and installation that can combine the low commercial costs of a relatively less complex open composting operation in which air is freely admitted to the composting mass to ensure sufficient oxygen is 30 available for efficient composting with a method of more effectively reducing the amount and type of odours emanating from the composting mass, i.e. to produce less malodours as a result of the composting processes and to N:\elboume\Cases\Patent\72000-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 -7 convert more of the malodorous materials that are produced to less malodorous materials. Accordingly, it is an aim of the present invention to 5 provide a composting cover which reduces the amount of odorous substances produced during composting whilst allowing the efficiency of the overall composting process to be maintained or enhanced. 10 It has now been surprisingly discovered by the present inventors that if a compost cover of the type herein described is used, not only is the amount of odours being produced reduced, but also the overall efficiency of the composting process is maintained by allowing optimum 15 quantities of air to be introduced into and/or through the composting mass. This control over the amount of oxygen being available for composting is associated with other attendant benefits. 20 The aim of the present invention has been met by the use of a newly developed layered compost cover and to methods of using the cover in an engineered composting system to control the composting processes as well as to control the emission of odours from the composting mass. 25 SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a compost cover capable of controlling the 30 emission of odorous substances from a composting mass or structure that produces the odorous substances during composting operation, said cover comprising a base layer being a low moisture retention layer having a N:\elb oume\Ceses\Patent\72000-72999\P72148 AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21 doc 5/06109 - 8 predetermined water and air permeability for transmitting a portion of water vapour/moisture produced by composting of the composting structure to an intermediate layer, said intermediate layer including at least one individual 5 micro-porous membrane layer having variable porosity and surface area for condensing and retaining water vapour within the membrane layer and a top layer of predetermined water and air permeability for controlling the degree to which water, is admitted to the composting structure 10 through the cover wherein the compost-derived water condensed within the intermediate layer through or by the base layer is retained in the intermediate layer to interact with the vapour of the odorous substances to convert the malodorous substance to a less unpleasant 15 substance so as to reduce the amount of odorous substance emitted from the composting structure through the top layer thereby reducing the emission of odours from the compost structure. 20 According to another aspect of the present invention there is provided a method of composting to reduce the emission of odorous substances from a composting structure comprising forming a compost structure, applying a composting cover to the composting structure, controlling 25 the amount of moisture admitted to the cover from the composting structure by trapping a proportion of the moisture produced by the composting structure within an intermediate layer of the cover wherein at least some of the odorous substance produced during composting of the 30 composting structure is converted to a less odorous material so that less odorous substance is emitted through the cover to externally of the cover. N :\elboume\Cases\Patent\72000-72999\P72148.AU 2\Specs\P72148.AU 2 Specification tracked 2009-5-21.doc 5106/09 - 9 According to another aspect of the present invention there is provided an engineered composting system for reducing the emission of odorous substances from a composting structure comprising a compost structure capable of 5 undergoing composting to produce a odorous substance, and a compost cover capable of at least partially enveloping the compost structure wherein the compost cover has a first layer for selectively allowing water vapour/moisture produced by composting of the compost structure to lo permeate through the first layer so as to limit the transmission of water vapour/moisture to a second layer of the compost cover, said second layer being arranged to retain at least some of the water obtained from condensation of the water vapour/moisture transmitted 15 through the first layer so that the retained water in the second layer assists in converting the odorous substances to less odorous materials so that the less odorous substance is available for transmission through a third layer of the compost cover to atmosphere outside the 20 compost cover and/or structure so as to reduce the amount of odorous substance released for the compost structure when fitted with the compost cover. BRIEF DESCRIPTION OF ASPECTS OF THE INVENTION 25 BASE LAYER Typically, the first layer is a base layer. More typically, the base layer is a single layer. More typically, the base layer is a low moisture retention 30 layer. Typically, the base layer is made from tough non biodegradable plastic such as woven polypropylene. In one form the base layer maximises condensation of N:\Melboume\Cases\Patent\72000-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21 doc 5106/09 - 10 rising expelled air, particularly moisture containing air. In one form the base layer is omitted from the second layer or intermediate layer but rather is joined to the intermediate layer along one or more edges of the base 5 layer. The base layer is present to provide mechanical strength for the compost cover and to contain the intermediate layers within the cover and also to keep the intermediate 10 layers clean. Preferably, the base layer has the preferred characteristic of being a strong woven fabric of various porosities and low water holding. Typical examples of the materials from which the base 15 layer can be made include plastics such as woven or knitted polypropylene, PVC or nylon. INTERMEDIATE LAYER Typically the second layer is an intermediate layer. More 20 typically, the intermediate layer comprises one, two, three, four or more individual layers arranged in a layered structure, laminate structure, composite structure or similar in which the layers are located adjacent one another, preferably, superposed over one another or 25 overlapping with each other. More typically, as many layers are chosen as is required to obtain a given moisture retention and thickness for the given composting application. 30 In one form the intermediate layer includes four individual layers. The four individual layers forming the intermediate layer are sandwiched between the top layer and the base layer. In another form, less than four N \Melboume\Case\Paten\720O0-72999\P72148.AU-2\Specis\P72148.AU.2 Specrfication tracked 2009-5-21 doc 5/06/09 - 11 individual layers form the intermediate layer. However, in this form, the layers are thicker than the individual layers when there are more layers. The individual intermediate layers are attached to the top layer and the 5 base layer. More typically, the base layer or top layer is located outwardly of the intermediate layer so that the base layer or top layer, are outer layers. In one typical form the base layer is joined to the edges of the intermediate layer and is superposed on or covers the 10 intermediate layers. In one typical form of the compost cover of the present invention, the multi-layered part of the cover extends over the top portion of the compost structure, 15 particularly over the entire top surface of the compost structure and partially down the sides of the compost structure. More typically, the multi-layered section is the mid 20 section of the cover for fitting over the top of the compost structure. Even more typically, the multi-layered section is the upper section in use of the cover. In one form the multi-layer extends from part way along one the side of the compost structure, over the top of the compost 25 structure, to extend part way down the wall on the other side of the compost structure. Typically, the individual layers forming the intermediate layer have variable but high porosity and thickness. 30 Typically thickness will range from 4 to 10mm with total porosity 60-80% by volume. More typically, the individual layers may have the same porosity as one another or have different porosities from one another including N:\Melboume\Cases\Patent\72000-72999\P72148.AU.2\Specis\P72148.AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 12 combinations thereof. Typically the four intermediate layers are made from a felted polypropylene structure which is variously "fluffy" and has a low strength or other durable high porosity, usually synthetic material 5 either as a fabric or composite fabric structure like "box quilted" and padded materials or similar. Padding and wadding of composite structures is most typically synthetic fibre such as "dacron" or similar. In one form shredded recycled plastic shreds may be used to provide 10 surface area and volume. Often the intermediate layer will clog with dirt and needs to be kept clean, such as by the base layer and/or top layer. Preferably such materials will be non-biodegradable 15 plastics including such materials as shredded recycled plastics, felted polypropylene (eg Bidum@) or synthetic foam rubber. In one form the four intermediate layers have high water 20 holding ability, particularly high retention of the water transmitted through the base layer or water condensed on or within the intermediate layer. In one form of the invention, the individual layers, in 25 particular the intermediate layer, provide a suitable environment (moisture, water holding, and aeration) for the establishment of endogenous or introduced micro flora. This microflora enhances the biodegradation of condensed volatile organics compounds. The structure of the fabric 30 from which the individual layers are manufactured are conductive to retaining micro-organisms on or within the structure. Preferably, adapted micro-organisms will colonise in conditions where substrates and environments N:\Melboume\Cases\Patent\720O0-72999\P72148.AU-2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 13 present are consistent with their requirements for growth. In this invention the conditions can be anticipated to allow the pre-introduction of a micro-organism, for example, microorganisms known to oxidise sulphur and 5 nitrogen compounds. Typically, the structure of the material from which the intermediate layer is made is provided with voids, apertures, openings, cavities or the like for retaining 10 the microbes, condensing and retaining moisture, allowing gaseous exchange, holding warmth and odour derived nutrients so as to generally enhance their multiplication and growth. 15 In one form the intermediate layer not only provides for growth of odour scrubbing micro-organisms but is used to absorb chemical scrubbing agents so as to enhance removal of odour molecules from the expelled air stream. In one form, the material from which the intermediate layer is 20 made is impregnated with the chemical scrubbing agents. These chemical agents are chosen according to types of chemical odours produced by the compost and to the anticipated needs of the micro-organisms. In the instance of compost producing high nitrogen content odours, such as 25 for example, ammonia and amines, an organic acid is applied as the chemical scrubbing agent which has a twofold benefit of providing an acidic environment for condensation of the nitrogen forms, as well as providing an energy substrate to enhance the growth and nitrogen 30 utilisation by the microbes. In an alternative process where reduced sulphur compounds are formed, calcium, hydroxide, or other hydroxides may be applied to the material of the intermediate layer to condense the sulphur N:\Melboume\Cases\Patent\72000-729 \P72148.AU 2\Specas\P72148.AU-2 Specification tracked 2009-5-21 doc 5/06/09 - 14 compounds and reduce their vapour pressure within the intermediate layers thus enhancing the ability of the intermediate layer to scrub out such malodours from the expelled air stream. 5 TOP LAYER Typically, the top layer is an outer layer which has an outer surface that is exposed to the weather, to the elements, wind, sunlight, rain, or the like. In one form 10 the top layer is a tough woven polypropylene layer providing strength and durability to the compost cover. It is to be noted that properties such as for example, the material being non degradable and UV stabilised are some of the main requirements for the material from which the 15 top layer is made, otherwise any number of plastic products can be used. The main type of plastic is polypropylene. In one form the outer layer is sufficiently porous to 20 allow expelled air to escape from within the cover to the atmosphere outside the cover. In one form the outer layer is sufficiently impervious to water striking the layer from outside to shed or repel the majority of the water, particularly to direct rainwater down the sides of the 25 cover to a suitable drainage channel or similar. More typically, the top layer overlies the intermediate layers. More typically, the top layer extends from one side of the compost structure over the top of the compost structure and down the other side of the structure. 30 VENTILATION PANEL Typically, the cover further comprises, or includes one or more ventilation panels. The ventilation panel is a N:\elb oume\Cases\Patent\72000-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 15 convection ventilation panel or an extraction ventilation panel. More typically the ventilation panel is an open weave panel for admitting air therethrough. Even more typically, in one form the ventilation panel provides 5 substantially uninhibited natural convection aeration through the compost structure by admitting air from outside the composting structure for circulation through the compost structure, preferably freely admitted air to ensure optimal aerobic conditions are established and/or 10 maintained in the composting structure. Typically, the convection ventilation panel is located at or towards one side of the composting structure. More typically, the ventilation panel is located at or towards 15 two or more sides of the compost structure, preferably along or in, at least partially, both sloping sides of the compost structure. Even more typically, the ventilation panel is located in the lower part of the compost cover, near to the ground, and preferably extends about a third 20 of the height of the top layer. Typically, the ventilation panel is provided in the top layer or in the base layer or in both the top layer and base layer. More typically, the ventilation panel 25 excludes the intermediate layer. Pads of the ventilation panel may be aligned with each other or offset from one another. Typically, the ventilation panel covers part of the side 30 or sides of the compost structure, more typically, the lower part or parts of one or both of the sides of the compost structure. N:\Melboume\Cases\Patent\72000-72999\P72148 AU 2\SpecisP72148 AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 16 Typically, the ventilation panel is a continuation of the base layer or is provided in the base layer. Typically, the ventilation panel is made from an open 5 weave material including a natural material, a man made material, a plastics material, a synthetic material, or the like. More particularly, the synthetic or plastics material is woven polypropylene or similar material. Typically, the structure of the open weave is a knitted or 10 simple woven polypropylene of air permeability chosen to provide sufficient air permeability for the given composting type. In typical yard or green waste composting a woven polypropylene usually provides sufficient air permeability. Where very high compost metabolic rate is 15 anticipated, for example with sewage or manure composting, the most typical form would be to choose the more high permeability such as "knitted" type of fabric. Open weave or knitted polypropylene is the example of the 20 material from which the ventilation panel can be made. The polypropylene is preferably UV stabilised and non biodegradable. OTHER FEATURES OF THE COVER 25 In one form the compost cover is provided with a anchoring system. One form of the anchoring system is a sewn-in flexible lay-flat hose arranged to extend around the edge or periphery of the cover, preferably below the level of the convection ventilation panel or panels. In another 30 form the hose forms a channel. The channel can be an open channel or a closed channel. The channel can be filled with water or other fluid to anchor the cover over the composting structure. Alternative anchoring means are N:\Meltoume\Cases\Patent\72000-72999\P72148 AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06109 - 17 also possible, such as for example, mechanical anchoring means such as for example, fasteners, hooks, pegs, pins, weights, ropes or the like. s In one form the compost cover is an integral cover in which the individual layers are integral with each other such as for example, being sewn into a single tough reusable cover system or are adhered to each other by a suitable adhesive or the like. Alternatively, the cover 10 can be made as separate individual layers that are located one upon the other over the compost structure. The cover can be made from any suitable material such as for example, natural fabrics, synthetic fabrics, man made fabrics including combinations of different fabrics or the 15 like. EXTRACTION SYSTEM In one form of the extraction system employed in the cover of the present invention, the compost cover is supported 20 in place, at or towards the top of the compost structure by a support structure or support assembly. More typically, the support assembly includes a support framework or similar. In one form, the support framework is a support frame comprising one or more support members 25 interconnected together to support the underside of the top portion or section of the compost cover in use, either directly or indirectly, such as for example, in spaced apart relationship from the top of the compost structure. Typically, there is a single complex frame member or two 30 or more frame members interconnected together. Typically, the spaced part relationship includes a space, gap, void, cavity, chamber, plenum or the like. In one form, the framework members are made from stainless steel. In other N:Melboume\Cases\Patent\72000-72999\P72148.AU 2\Specis\P72148 AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 18 forms, the framework can be made from any suitable material, particularly materials which are rust and /or corrosion resistant. 5 Typically, an extraction assembly, device, installation, system or similar is located in the space between the top of the compost structure and the undersurface of the top layer, portion, section or similar of the compost cover. In one form, the extraction arrangement includes a gas 10 catchment system for capturing volatile materials, such as volatile organic compounds (VOC). In one form, the extraction arrangement includes a collection device for the vapours and volatile materials. In one form, the collection device is a perforated tube provided with a 15 plurality of inlets, openings, apertures, or the like, typically in more or less regularly spaced apart relationship over the length of the tube, for use in extracting vapour from the top space of the compost structure. In one form, the perforated tube is under 20 negative pressure so as to vent the VOC gases and vapours to vent the VOC gases to a bio filter or similar collection device located outside of the compost cover and/or compost structure for treatment to remove odorous compounds prior to venting to atmosphere. In some 25 embodiments, there is an extraction ventilation panel located at the top of the compost structure whereas in other embodiments, there is a capture hood arrangement. Typically, the top of the compost cover is provided with 30 flaps, more typically, sealing flaps which are reversibly sealable to one another or to other parts of the compost cover to seal the top of the cover above and to the side of the collection tube. In one form, the flaps of the N:\elbourne\Cases\Patent\72000-72999\P7214B AU 2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 19 compost cover are provided with releasably securable fasteners or resealable fasteners, such as for example, Velcro@ fasteners, strips, pads or the like. 5 In one embodiment, there is a single perforated collection tube whereas in other embodiments, there are two or more collection tubes, optionally interconnected together. In one form, the active windrows are covered with a multi 10 layer cover system. The impermeable layer of the cover has large openings along the base of the windrow, to allow air to be drawn through the compost into the extraction system. The 1-2 metre gap in this cover at the base of the windrow, decreases in area as the windrow decreases in 15 volume and height through the composting process. A custom made frame is positioned along the ridge of the windrow. The purpose of this frame is to support the extraction duct and provide a cavity for the duct that 20 remains open as the windrow settles and shrinks. An impermeable ridge cover will be installed over the frame and extraction duct system. Air is drawn from each of the windrows to a bio filter or 25 scrubber located downstream of the compost area. A single collection header duct is used, feeding to the duty/standby extraction fan. In another form, the extraction system for withdrawing VOC 30 from the installation includes a non permeable membrane and a "capture hood" installed at the apex of the compost structure or pile. This type of extraction system does usually require a framework support. The installation and N :Melbourne\Cases\Patent\7200-72999\P72148 AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21 doc 5/06/09 - 20 configuration of the capture hood at or towards the top of the compost structure allows VOC materials to be extracted and contained. In one form, the capture hood is in the form of a single layer of impermeable membrane. 5 It is to be noted that either type of extraction system comprising either the extraction ventilation panel located at the top of the compost pile, or the capture hood extraction system operated under negative pressure, can be 10 used with the multi layered compost cover of the present invention to remove volatile, or gaseous compost products or degradation products from the compost structure or pile. 15 COMPOST STRUCTURE Typically, the raw material that is to be composted using the cover of the present invention can be any suitable material that degrades. In one form the compost material is a vegetable refuse or vegetation waste or rubbish such 20 as for example a yard waste, green waste, green organic waste, organic waste or the like obtained from environments such as urban, private or public gardens, vegetation clearance for construction and infrastructure maintenance. Typical examples include grass clippings, 25 leaves, twigs, foliage or the like. However, it is to be noted that the present invention can be used for all materials capable of being composted and by all composting processes. Other examples of material include composting of sewage sludge, wood chips, animal wastes, food 30 processing wastes and the like including combinations of two or more of the above such as sewage sludge mixed with yard waste or wood chips. Other examples include materials having highly available carbon substrate, N:\Melboume\Cases\Patent\72000-72999\P72148 AU 2 pecis\P72148 AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 21 materials rich in nutrients or the like. Yard waste composting (with or without sewage sludge addition) is of an economic benefit producing commercially 5 valuable products such as erosion control and decorative garden mulches, improving agents for agriculture and horticulture generally, potting mixes, or similar useful products. It also results in considerable reduction of landfill volumes having indirect commercial value. 10 Typically, the yard waste or other composting waste are ground to a particle size likely to promote, maximise and/or optimise air flow through the composting material whilst being of a fine enough particle size to increase is availability of the carbon substrate of the vegetation waste to micro-organisms for degradation by suitable processes. Typically in composting processes it is desirable to provide sufficient porosity such that natural or enhanced ventilation can maintain at least partially 20 aerobic conditions. This can be obtained by choosing components and mixing components in such ratio as to enhance or control such permeability. Typically, water may be added to the composting waste if 25 required. The water can be added to the compost mixture as it is being formed such as by blending, mixing or the like or after the structure has been formed during composting. 30 Typically, the compost is in the form of a compost structure, compost assemblage, compost mass or biomass, compost heap, compost hill, compost pile or any other suitable shape or arrangement. N:\Melboume\Cases\Patent\72000-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21 doc 5/06/09 - 22 Typically, the compost structure can take any suitable form. One form is an open form or a bay form. More typically, the open form is a windrow form, preferably an 5 open windrow form or open pile, such as for example, of a generally rectangular pyramid shape having a truncated or flat top and sloping sides, such as a trapezium like cross-section or similar. In one form, the open windrow is made from two sides, preferably two sloping sides in 10 which the sides are convergingly inclined towards one another in the direction from the base of the windrow side to the top of the windrow. The windrows can be of any suitable height, length or width, and take any suitable shape or ratio of height to width or the like. For the 15 purposes of the economic conservation of space within composting facilities windrows typically have both convergent sloping sides and flat tops. The wider the flat top, the more favourable being the surface area to volume ratio, to assist in efficient composting of the waste 20 material. Typically, the height, length, and width of the pile or windrow is most beneficially optimised to provide for natural convection aeration of the windrow, particularly 25 by admitting air through the lower part of the converging sloping sides of the windrow. However, as the width of the flat top of the windrow increases it is usual to find that optimum natural ventilation declines and cannot maintain aeration throughout the whole composting mass leading to 30 anaerobic conditions. Typically, the process or processes which result in the production of odours generally regarded as malodorous N:\Melboume\Cases Patent\72O0-72999\P72148 AU 2\Specis\P72148 AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 23 perception in humans are generally anaerobic or partly anaerobic processes which are also termed 'fermentation' processes. 5 Typically, the chemical class of compounds responsible for the malodours include mercaptans, alkyl-sulphides, organic sulphides, inorganic sulphides, aldehydes, alcohols, carboxylic acids, amines, ammonia, skatols, alkylamines and the like. More typically, the yard waste degradation 10 include mainly aldehyde/carboxylic acid compounds, mercaptans and organic sulphides. As an example grass clippings have a relatively high sulphur content so that the composting of yard waste containing a high content of grass clippings will produce sulphur related decomposition 15 products having a sulphurous malodour. Typically, the malodours or odorous products are formed in the composing process, such as for example, usually from 3 to 5 weeks or the like, when the compost process is in the 20 initial or 'unstable' composting phase. More typically, odours are expelled from the top of the windrow or pile as warm air rises and carries odorous compounds along with it as it rises. More typically, the warm air also contains moisture, water vapour or the like. 25 Typically, the composting process to which the compost cover of the present invention is applied includes additional steps and/or features. One of the additional steps or features is applying positive forced aeration 30 systems to the composting structures which are above the optimal size for naturally ventilated systems such as wide flat topped windrows, piles or the like. This is a method whereby air is pumped via fans into the compost structure N:Melboume\CasestPatent\72000-72999\P72148.AU.2\Specis\P72148.AU-2 Specificaion tracked 2009-5-21 doc 5/06/09 - 24 through various ducting with the aim of improving aeration thereby reducing anaerobic odour production and hastening the composting process. An example of this is the 'Beltsville Pile' method. 5 Another of the additional steps or features is negative forced aeration whereby air is evacuated, extracted, discharged, withdrawn or the like, from the compost structure so that the odour can be removed along with the 10 forced extraction of air through the collection device or arrangement including the perforated collection tube for removal and from the compost structure. Typically the compost cover of the present invention 15 controls the emission of odours by an odour management method which is a combination of physical and chemical methods relying upon the condensation of moisture from the vapours produced during composting and the concurrent condensation of water soluble odour compounds in the 20 condensed water which is retained on or in the intermediate layer. The cover will provide such odour reduction benefits in the case of both naturally and forced aeration ventilation systems and provides an improvement in the conduct of both systems. 25 The compost cover of the present invention is an engineered compost cover developed for the enhanced processing of static pile or bay composting structures, such as for example, compost arrays arranged in windrows 30 out in the open exposed to the atmosphere. The compost cover of the present invention uses several methods of odour management to achieve a low emission of odorous materials or substances. One of the odour management N:\Melboume\Cases\Patent\720O0-72999\P72148 AU.2\SpecisP72148 AU.2 Specification tracked 2009-5-21. doc 5106/09 - 25 methods involves condensation of moisture on the lower surface barrier which can be the base layer or the lowermost layer of the intermediate layer and the concomitant condensation of odour molecules in the water 5 being condensed on the lower surface barrier. Further condensation of water and concomitantly odour molecules occurs in and on one or more of the individual layers of the intermediate layer which are the inner absorptive layers, particularly as such form a support substrate for 10 supporting microbial growth on the layers for oxidative destruction of the odour by oxidising the odour molecules. A porous but durable upper layer in the form of the top layer protects the compost structure against mechanical damage and prevents excessive moisture from rainfall or 15 the like from entering the compost structure. The rainwater is directed towards and down the sides of the compost cover. The top cover is porous to allow the escape of vapours and gaseous materials from within the composting structure to the atmosphere. 20 A preferred feature of the compost cover of the present invention is the optional use of odour specific chemical agents applied to or on or within the inner absorptive layer to act as a wet scrubber to assist in removing the 25 odour molecules such as by solubilising the odour molecules in the water retained on the intermediate layer thereby preventing the odour from being transmitted through the intermediate layer and/or top layer for escape to the atmosphere. 30 In addition, aspects of the present invention include providing further enhancement methods and devices for odour capture and scrubbing. Under conditions of severe N:Welboum\Cases\Patent\720O0-72999\P72148.AU 2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06109 - 26 odour production, such as for example, refuse or waste having a high manure or animal waste content can involve the installation of porous piping under the compost cover, typically at the apex of the pile or along the upper 5 portion of the pile in any arrangement, configuration, or number as required. One form of the porous piping is slotted plastic agricultural drainage pipe. Typically, the extraction arrangement comprising the 10 perforated collection tube or other porous pipes or similar, are evacuated using mechanical fans or 'negative pressure' to extract highly malodorous air from the apex of the pile so that it can be concentrated for treatment by conventional wet scrubbing, by a filtration and/or 15 stack dispersion, or other suitable methods or devices. In such high odour composting environments it may be additionally advantageous to use non-permeable covers such as PVC or butyl rubber sheeting as the cover and combine 20 this with the "capture hood" installation as previously described. The purpose of this cover being to use mechanical means (fans etc) to maintain negative pressure at the apex of the pile and capture all escaping VOCs which are then scrubbed or degraded in external odour 25 capture and degradation units eg bio filters or chemical scrubbers. One particularly preferred form of the arrangement of the present invention includes the following. One set of 30 particular features that are unique to this cover are: 1. The compost cover is in the form of modular sections 18.33m in length that zip together with heavy N:\Melb oure\Cases\Patent\72000-72999\P72148.AU.2\Specs\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 27 duty nylon zips for ease of handling and transport (reduced weight). 2. The covers have sown-in lifting lugs for handling 5 3. The covers are provided with side convection ventilation panels that assist natural air movement. 4. The construction of the covers includes multi 10 layered, (typically three layered) AEROSORB@ membrane panels over the top of the pile forming the compost structure that acts to insulate the composting mass and condense water vapour and odour molecules (Volatile Organic Carbon compounds or VOC's) 15 5. At the peak of the pile, there is a sealed impermeable panel section that can be zipped over the AEROSORB multilayer section or can replace the multilayered Aerosorb panel completely. This allows a 20 perforated pipe to be inserted so that malodorous air containing VOCs emanating from the pile can be collected via the use of negative air pressure (suction pumps) and scrubbed either chemically or by passing through a bio filter layer. This important innovation allows expelled 25 air capture and replaces the need for enclosure of the entire composting facility. It is the inability to capture expelled air in a positive pressurised aerated pile that results in odour problems for composting facilities and usually requires such facilities to be enclosed within 30 built structures. The new cover arrangement and especially the use of an impermeable cover over the upper section of the windrow, of the present invention is an innovation that provides a considerable cost advantage for composting N:\Melboume\Cases\Patent\720O0-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 28 facilities close to urban and especially residential areas, particularly when the composting occurs under ideal or optimal aerobic composting conditions using controlled amounts of oxygen from the air introduced into the 5 composting windrow through the ventilation panels of the cover. Another preferred form of the invention includes the following. 10 One form of the extraction system includes a single impermeable membrane with a capture hood. In this form, the single membrane does not substantially adsorb the moisture and odour but simply confines air flow so that 15 the capture hood removes substantially all of the air, odour and moisture for external scrubbing through a bio filter or chemical scrubber. A preferred form of the invention includes the following: 20 1. A lower panel that is permeable to allow air to enter, such as for example, allowing convection ventilation using a suitable convection ventilation panel located about 1/3 up the side of the composting pile. 25 2. An upper section that is impermeable heavy duty UV stabilized PVC or butyl rubber membrane covering the top 2/3 of the pile located on either side of the pile. 30 3. An upper "capture hood" that contains a stainless steel frame and impermeable cover. 4. Negative air pressure existing within the capture N:\Melboume\Cases\Patent\720O0-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 29 hood to withdraw VOC. 5. Passive or positive air pressure beneath the pile to supply air to the compost structure for aerobic 5 composting to occur. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described by way of 10 example with reference to the accompanying drawings in which: Figure 1 is a schematic sectional view through one cross section of one form of the compost structure showing one 15 form of the compost cover in accordance with the present invention located over the top of the structure. Figure 2 is a schematic cross-sectional view of one form of the construction of the compost cover of the present 20 invention showing the different layers forming the cover. Figure 3 is a schematic flow diagram illustrating one form of the process of composting using a composting structure having a compost cover in accordance with the present 25 invention. Figure 4 is a schematic partial top plan view of one part of another form of a compost structure and compost cover of the present invention. 30 Figure 5 is a schematic cross-sectional view taken along the line 5-5 of Figure 4. N:\elboume\Cases\Patent\72000-72999\P72148.AU 2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5106109 - 30 Figure 6 is an enlarged schematic view of the top of one form of the compost cover showing one form of the extraction arrangement. 5 DETAILED DESCRIPTION One form of the Engineered Composting system including the compost cover in accordance with the present invention will now be described. 10 In one form, organic waste material, such as for example, yard waste including grass clippings, leaves and other vegetative material is collected at a collection site, and in some circumstances transported from the collection site is to the composting site where, after shredding, mixing or blending, the relatively homogeneous mixture formed from these steps is stacked or heaped into a suitable composting structure, such as for example, an open windrow 10 having a pair of sloping sides 12 on either side of the 20 windrow. The windrow has a base portion 14 and a top surface 16. In some forms of the invention, including the form schematically illustrated in Figure 1, there is an array of interconnected slotted pipes 18 provided at or about the base 14 of windrow 10. Air is pumped through 25 pipes 18 from a suitable source using a suitable pump (not shown) for distribution through the array of pipes 18 having air inlets 19 associated therewith to form an optional positive forced aeration system for the windrow 10 to assist in aerating the windrow by providing 30 sufficient oxygen for aerobic metabolism to take place within the windrow to not only assist in hastening the composting process but also to reduce the amount of malodorous molecules being produced during the composting N:\Meboume\Cases\Patent\7200O-72999\P72148 AU.2\Specis\P72148 AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 31 process by inhibiting anaerobic fermentation which is the usual source of many of the more malodorous molecules which are offensive to humans. The production of such malodorous molecules does not occur to anywhere near the s same extent under aerobic conditions. A multi-layered compost cover 20 comprising a base layer 22, an intermediate layer 24 comprising four individual layers 26, as shown schematically in Figure 2, and a top 10 layer 28 is fitted over the top surface 16 of windrow 10 to extend downwards along both of the sloping sides 12 of windrow 10 to be securely anchored to the ground or foundation underneath windrow 10 around the base 14 of windrow 10 by a suitable anchor arrangement. In one form 15 the anchor arrangement is an enclosed tube that can be filled with water, such as for example, a long lay-flat hose provided with suitable connectors and fittings that can be filled with water, particularly run off water from the top surface 28 of cover 20 into the hose. 20 In one form cover 20 is provided with one or more convection ventilation panels 30 located in the lower parts of the sides of cover 20, preferably in top layer 28. However, ventilation panels 30 can be located in both 25 top layer 28 and bottom layer 22 if required. The ventilation panels can be of an open weave material. In one form the base layer 22 of the cover 20 forms the ventilation panels 30. The presence of the ventilation panels in the base layer allows uninhibited natural 30 convection aeration by allowing air to enter the windrow and be circulated through the windrow to promote aerobic fermentation, such as for example, as illustrated schematically by arrow A of Figure 1. N: \elboume\Cases\Patent\72000-72999P72148.AU.2\Specis\P72148.AU.2 Specfication tracked 2009-5-21.doc 5/06/09 - 32 The intermediate layer 24 is structured so as to physically and chemically retain water, particularly water condensate, on and within the layers. If required the 5 individual layers 26 forming the intermediate layer can be provided with the chemical agents for assisting in retaining water and condensing the water. Additionally, the individual layers form substrates for retaining micro organisms for converting the odour molecules to less 10 malodorous molecules, such as by solubilising the odour molecules. In one form the intermediate layer is a layer of non-woven polypropylene with high porosity and surface area which filters moisture and particulates and supports an active bio-layer of odour consuming micro-organisms 15 arriving either by natural colonisation or by deliberate selection and introduction. The intermediate layer extends part way up one side of the windrow, over the top surface and part way down the other side of the windrow to form a cap over the top of the windrow but allows air to 20 enter the sides of the windrow below the cap such as for example, as indicated by arrow A in Figure 1 to establish and/or maintain aerobic composting conditions. Top layer 28 forming an outer layer of compost cover 20, 25 is provided over the outer surface of the intermediate layer 24 and extends over the intermediate layer from one side of windrow 10 to the other side as shown in Figure 1. In one form, an extraction arrangement 34 in the form of a 30 collection array comprising an arrangement of interconnected pipes 36 is provided at or towards top surface 16 of windrow 10 to allow extraction of malodours from the composting windrow 10. Pipes 36 located at the N:\elboume\Cases\Patent\72000-72999\P72148.AU.2\Specis\P72148.AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 33 apex of windrow 10 are in fluid communication with a manifold 37, and with extraction fan 38 and a wet scrubber or stack 40 thus forming an extraction network for the odorous molecules expelled along with air from the top of 5 the windrow using negative pressure. Again pipes 36 are slotted plastic agricultural drainage pipes, perforated plastic pipes or similar conduits. Operation of the present invention will now be described. 10 After the windrow 10 has been formed and cover 20 located in place composting of the windrow commences after air is optionally introduced to the base 14 of windrow 10 through pipes 18 so that warm moisture laden air produced as a result of composting rises from the interior of windrow 10 15 to partially condense on the cooler lower surface of the base layer together with condensation of some of the odour molecules that are being produced during the composting processes. Condensed water and odour molecules then return to the windrow by simple gravitational flow of the 20 condensate. This condensation of the main part of the moisture being produced by the windrow tends to conserve moisture losses from the windrow and allows microbes present in the compost structure to further degrade the odour molecules thus reducing the amount of offensive 25 molecules being produced by the composting processes. Part of the water vapour/moisture is transmitted through the base layer, and contacts the lowermost layer of the intermediate layer to condense within the intermediate layer to form water droplets. The water condensate formed 30 in the intermediate layer solubilises the odour molecules so as to condense further quantities of the odour molecules. It is to be noted that in this layer oxidation, autolysis, photolysis and biodegradation (bio N:\Melboume\Cases\Patent\72O0-72999\P72148.AU-2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5106109 - 34 oxidation) all occur. Thus, the water present in the intermediate layer retains the odorous molecules while conversion to a less odorous material occurs or retains the odorous material within the composting structure 5 preventing escape of the odorous material from the compost structure. The intermediate layer therefore acts as a diffuse bio filter and optionally a wet scrubber. Thus, the majority of odorous molecules are screened or filtered from being emitted through the top layer of the cover 10 since less are produced in the first place and of these, more are converted or neutralised under the cover. The range of odours produced during the initial active composting phase are readily absorbed onto moisture 15 droplets within the environment inside the cover particularly the intermediate layer which acts like a wet scrubber allowing for retention of odorous molecules during which time all of the processes take place to a greater or lesser degree. The end result being that the 20 concentration of malodorous compounds which would otherwise have been vented to atmosphere is greatly reduced by having being converted into less odorous species. This is particularly the case in respect of highly odorous reduced sulphur compounds which are 25 oxidised to non-odorous sulphates whilst resident in the moist microbial environment formed by the intermediate layers of the cover of the present invention. One example of the present invention will now be described 30 to illustrate one form of the invention. EXAMPLE 1 Upon arrival at the composting site, the yard waste is N:\Melboume\Cases\Patent\72000-72999\P72148 AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 35 located in a receival pile 52, or heap where it can be inspected and treated, such as for example, for the removal of contaminants, blending of different materials to make a homogenous mixture and similar 54. The pile is 5 treated as soon as possible after receival such as for example, within four hours maximum by blending in the ratio of three volumes of odorous waste material with one volume of shredded green waste and a capping with a 200 mm layer of mature compost. This mixture is then shredded 10 56, to produce a homogeneous feed stock. If necessary or appropriate, water can be added 58 to the mixture as required. Alternatively, as the composting operations proceed the 15 ratio of waste material forming the windrow can be changed to two parts green waste 82, one part bio-solids 84, and one part mature compost 86 by volume. When the windrow is formed and the cover of the present invention located in place, monitoring probes are inserted at appropriate 20 locations within the windrow. By admitting air to the windrow through the ventilation panels at the side of the cover it is possible to control the composting process within the windrow by varying the amount of air admitted to the windrow which regulates temperatures and oxygen 25 which in turn are responsible for control of the internal microbial activity within the windrow 60. This process control enables the optimisation of temperature and amount of oxygen within the windrow to provide a near to perfect environment for beneficial microbial and micro-floral 30 development not only within the composting biomass but also within the layers of the cover so as to create the bio filter layer for each windrow. N:Velboume\Cses\Patent\72O0-72999\P72148.AU.2\Speas\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 36 Using the probes to monitor the water content of the biomass additional water is added to raise the level of moisture in the biomass as required depending upon composting conditions. A bio-filter cap of up to 30 mm 5 thick of mature compost is applied to the top of the windrow to assist in maturation of the composting process 62. After composting is complete, composted material is removed for screening and classification 64 prior to storing in appropriate stock piles awaiting sale or use, 10 such as for example, transport to customers and users of the compost. Aspects of the process of the present invention include aerobic absorption and neutralisation of odours, 15 continuous control of temperature to maintain aerobic composting process and to kill unwanted pathogens, rainwater deflection and leech aide control, regulation of aerated control system, supplying air to the process as required and the delivery of a stable and mature composted 20 product suitable for reuse. Another example of the present invention will now be described with reference to Figures 4 to 6 which show another embodiment of the compost cover. 25 This form of the cover, generally denoted as 70 is provided with a single side skirt or sealing skirt 72 extending around the entire perimeter of cover 70. A multitude of hand grips 74 are provided in pairs at 30 selected spaced apart locations over the surface of cover 70 to facilitate positioning and moving cover 70. A multitude of hand hauling lugs 76 incorporating webbing lugs for water ballast pipes are provided at spaced apart N \Melboume\Cases\Patent\720O0-72999\P72148.AU.2\Specis\P72148AU.2 Specification tracked 2009-5-21.doc 506/09 - 37 locations around the perimeter of cover 70 near the sealing skirt 72. Cover 70 includes convection ventilation panel 78 located 5 around the perimeter of cover 70 adjacent sealing skirt 72 for allowing air to be admitted to the compost windrow located within the underneath cover 70. A non permeable portion 80 of cover 70 forming part of the top layer of cover 70 forms the upper top section of the cover. A 10 volatile organic compound catchment system ("capture hood") 82 is located along the central lengthwise extending axis of the cover at the upper surface of cover 70. the catchment system 82 also includes a ventilation panel 84 to vent volatile organic compounds into the 15 catchment system and is located underneath the top of over 70 along the central axis as shown more particularly in Figures 5 and 6. With particular reference to Figures 5 and 6, one form of 20 the catchment system 82 will now be described. Windrow 10 is located within cover 70 so that catchment system 82 is located on the top surface 16 of windrow 10. Catchment system 82 includes an extraction arrangement in the form of elongate cylindrical perforated extraction collection 25 tube 88 extending lengthwise along the central longitudinal axis of windrow 10 located within elongate, lengthwise extending space or void 90 formed under generally arcuate elongate lengthwise extending support frame 92 forming a hood for supporting top 94 of cover 70. 30 In operation, air from outside windrow 10 is admitted through convection ventilation panel 78 provided in one or more side walls of cover 70 to establish and/or maintain N:\Melboume\Cases\Patent\720O0-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06109 - 38 aerobic conditions within windrow 10. Warm moisture containing air together with odorous substances are recirculated and confined through windrow 10 by the action of the intermediate layer of cover 70 until they are 5 collected at or towards the top of windrow 10 in void 90 as indicated by arrows B of Figure 5. The gases, vapours, moisture, volatile compounds and the like are admitted to perforated tube 88 from void 90 by the action of the negative pressure in tube 88 for ultimate discharge from 10 the installation, after undergoing further treatment, such as for example, by filtering in a suitable bio-filter or the like. In this manifestation the cover 70 may more effectively be 15 an impermeable PVC or butyl rubber membrane that does not function like the multi-layered Aerosorb cover 22,24,26,28 but simply as a method of retaining all air flow within the pile 10. 20 Modifications to the invention include the following: Conditions for odour absorption and destruction within the inner absorbent layer can be enhanced by: * Applying irrigation water to prevent drying if necessary 25 e Addition of nutrients in the irrigation water e Adding chemical agents which further enhance the absorptive capacity and speed of the composting system including: e Oxidizing agents e.g. hypochlorite and peroxides 30 e Alkalis such as calcium hydroxide * Acids such as organic acids (e.g. citric acid) or inorganic acids (e.g. hydrochloric acids) N:\Melboume\Cases\Patent\72O0-72999\P72148 AU.2\Spocis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/06/09 - 39 " Synthetic deodorizing and absorptive agents e.g. synthetic polymers such as polyacrilamides e Natural products that are known to absorb odours such as clay minerals and other earths 5 . Catalysts such as titanium dioxide or copper salts known to catalyse oxidative reactions e Odour masking and deodorising agents like perfumes and odour compliment compounds 10 Advantages of the present invention include the following: Use of the compost cover and engineered composting system of the present invention will allow a compact and inexpensive system that will provide composted product at 15 an economically viable cost without having the attendant emission of excessive amounts of malodorous substances to annoy people in close proximity to the site. The described arrangement has been advanced by explanation 20 and many modifications may be made without departing from the spirit and scope of the invention which includes every novel feature and novel combination of features herein disclosed. 25 Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit 30 and scope. N \Melboume\Cases\Patent\72000-72999\P72148.AU-2\Specis\P72148.AU.2 Speaication tracked 2009-5-21 .doc 5106/09

Claims (34)

1. A compost cover capable of controlling the emission of odorous substances from a composting mass or 5 structure that produces the odorous substances during composting operation, said cover comprising a base layer being a low moisture retention layer having a predetermined water and air permeability for transmitting a portion of water vapour/moisture 10 produced by composting of the composting structure to an intermediate layer, said intermediate layer including at least one individual micro-porous membrane layer having variable porosity and surface area for condensing and retaining water vapour within 15 the membrane layer and a top layer of predetermined water and air permeability for controlling the degree to which water, is admitted to the composting structure through the cover wherein the compost derived water condensed within the intermediate layer 20 through or by the base layer is retained in the intermediate layer to interact with the vapour of the odorous substances to convert the malodorous substance to a less unpleasant substance so as to reduce the amount of odorous substance emitted from 25 the composting structure through the top layer thereby reducing the emission of odours from the compost structure.

2. A method of composting to reduce the emission of 30 odorous substances from a composting structure comprising forming a compost structure, applying a composting cover to the composting structure, controlling the amount of moisture admitted to the N:\Melboume\Cases\Patent\7200D-72999\P72148 AU.2\Specis\P72148.AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 41 cover from the composting structure by trapping a proportion of the moisture produced by the composting structure within an intermediate layer of the cover wherein at least some of the odorous substance 5 produced during composting of the composting structure is converted to a less odorous material so that less odorous substance is emitted through the cover to externally of the cover. 10

3. An engineered composting system for reducing the emission of odorous substances from a composting structure comprising a compost structure capable of undergoing composting to produce a odorous substance, and a compost cover capable of at least partially 15 enveloping the compost structure wherein the compost cover has a first layer for selectively allowing water vapour/moisture produced by composting of the compost structure to permeate through the first layer so as to limit the transmission of water 20 vapour/moisture to a second layer of the compost cover, said second layer being arranged to retain at least some of the water obtained from condensation of the water vapour/moisture transmitted through the first layer so that the retained water in the second 25 layer assists in converting the odorous substances to less odorous materials so that the less odorous substance is available for transmission through a third layer of the compost cover to atmosphere outside the compost cover and/or structure so as to 30 reduce the amount of odorous substance released for the compost structure when fitted with the compost cover. N:\Melboume\Cases\Patent\72000-72999\P72148 AU 2\Specis\P72148 AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 42

4. A compost cover, method or system according to any preceding claim in which the first layer is a single base layer in the form of a low moisture retention layer. 5

5. A compost cover, method or system according to any preceding claim in which the base layer is made from woven polypropylene. 10

6. A compost cover, method or system according to any preceding claim further comprising a sealing skirt associated with the base layer for sealing the cover to the ground around the perimeter of the compost material. 15

7. A compost cover, method or system according to any preceding claim in which the base layer is fixedly anchored to a substrate around the perimeter of the composting structure in which the edge of the base 20 layer is provided with water retention means in the form of a drain, channel, hose, pipe, conduit or similar.

8. A compost cover, method or system according to any 25 preceding claim in which the second layer is one, two, three, four or more individual layers arranged with respect to each other to form a layered structure, laminate structure, composite structure or similar forming an intermediate layer. 30

9. A compost cover, method or system according to any preceding claim in which the intermediate layer or layers are moisture retention layers for retaining N:\Melboume\Cases\Patent\720O0-72999\P72148 AU 2\Specis\P72148 AU 2 Specification tracked 2009-5-21.doc 5/06/09 - 43 moisture, water vapour and similar.

10. A compost cover, method or system according to any preceding claim in which the top layer is an outer 5 layer having an outer surface made from a material which is sufficiently porous to allow expelled air to escape from within the cover to an extraction system but is sufficiently impervious to not admit water but rather to direct water down the sides of the cover to 10 a suitable collection device in the form of a draining channel or similar.

11. A compost cover, method or system according to any preceding claim in which the cover is in the form of 15 a multi layered arrangement wherein the multi layered section is located in or at the mid section of the cover for fitting over the top and upper side portion of the compost structure. 20

12. A compost cover, method or system according to any preceding claim in which at least one of the four intermediate layers is made from a felted polypropylene structure having a high porosity for absorbing water or similar. 25

13. A compost cover, method or system according to any preceding claim in which the intermediate layer is a high retention of water of layer for retaining of water transmitted through the base layer for 30 retaining water condensed on or within the intermediate layer.

14. A compost cover, method or system according to any N:\Melboume\Cases\Pateni\72000-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21 dcc 5/06/09 - 44 preceding claim in which one or more of the individual layers of the multi layered structure are provided with micro organisms for assisting composting of the material in the compost structure. 5

15. A compost cover, method or system according to any preceding claim in which one or more of the intermediate layers forming the multi layered structure is provided with chemical absorbing 10 scrubbing agents to effect removal of malodorous materials formed during composting processes of the compost structure.

16. A compost cover, method or system according to any 15 preceding claim in which the top layer is a woven polypropylene layer.

17. A compost cover, method or system according to any preceding claim in which the cover includes or 20 comprises a ventilation panel for admitting air therethrough to establish and/or maintain aerobic conditions within the composting structure by allowing air to circulate through the composting structure. 25

18. A compost cover, method or system according to any preceding claim in which the ventilation panel is a convection ventilation panel located at or towards one side of the composting structure such as along 30 the lower portions of the sloping side walls of the composting structure.

19. A compost cover, method or system according to any N:\Melbume\Cases\Patent\72000-72999\P72148.AU.2\Specis\P72148 AU.2 Specification tracked 2009-5-21.doc 5(06/09 - 45 preceding claim in which the convection panel is provided in the top layer or in the base layer or in both the top layer and base layer for permitting air to circulate through the composting structure. 5

20. A compost cover, method or system according to any preceding claim in which the convection ventilation panel is located around the perimeter of the compost structure at or towards the lower portion of the 10 sides of the cover.

21. A compost cover, method or system according to any preceding claim in which the convection ventilation panel is made from an open weave material including a is natural material, a man made material, a plastics material, a synthetic material, or a combination of two or more such materials, including woven polypropylene. 20

22. A compost cover, method or system according to any preceding claim further comprising an anchoring system for anchoring the cover around and on top of the compost structure. 25

23. A compost cover, method or system according to any preceding claim wherein the compost structure includes a support structure for supporting the top of the cover in use for allowing removal of malodorous materials from the compost structure 30 through or by the extraction system.

24. A compost cover, method or system according to any preceding claim wherein the support structure N \Melboume\Cases\Paten\72000-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21.doc 5/069ID - 46 includes a support assembly, support framework or support member for forming a space, void, cavity, chamber, plenum or similar intermediate the top of the compost structure and the undersurface of the top 5 of the cover for facilitating removal of malodorous products from the compost structure.

25. A compost cover, method or system according to any preceding claim wherein an extraction assembly, 10 device, installation or similar is located within the space intermediate the top of the compost structure and the undersurface of the compost cover in which the extracting system includes a gas catchment system for capturing volatile materials and conveying the is volatile materials away from the compost structure.

26. A compost cover, method or system according to any preceding claim in which the catchment system includes a collection device, preferably in the form 20 of a perforated tube provided with a plurality of openings or apertures for receiving malodorous compounds or materials therethrough.

27. A compost cover, method or system according to any 25 preceding claim in which the extraction device is operated under negative pressure to facilitate removal of malodorous materials.

28. A compost cover, method or system according to any 30 preceding claim wherein the compost structure includes green waste, vegetable waste, vegetation, yard waste, green organic waste. N:\Meiboume\Cases\Patent\720O-72999\P72148 AU.2\SpecJs\P72148.AU.2 Specification tracked 2009-5-21 doc 5106/09 - 47

29. A compost cover, method or system according to any preceding claim in which the composting of the compost structure occurs under aerobic conditions thereby reducing the amount of malodorous materials s being formed and facilitating conversion of the reduced number of malodorous compounds formed into substantially non offensive materials.

30. A compost cover, method or system according to any 10 preceding claim wherein the compost structure is in the form of a compost assemblage, compost mass, compost bio-mass, compost heap, compost hill, compost pile, compost windrow, open windrow, open pile, open stack or similar having a flat or truncated top or 15 upper surface and at least two sloping sides arranged to extend longitudinally with the lengthwise extending central axis.

31. A compost cover, method or system to further enhance 20 and reduce the emission of odorous substances from a composting structure comprising the steps of forming a compost structure, applying an impermeable membrane composting cover to at least the upper part of the composting structure, and installing an extraction 25 system in the form of a capture hood for extracting gaseous or vaporous or volatile materials from the composting structure. 30

32. A compost cover, method or system substantially as hereinbefore described with reference to the accompanying drawings. N:\Melboume\Cases\Paent\720O0-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21 doc 5/06/09 - 48

33. A compost cover, method or system substantially as hereinbefore described with reference to any one of the foregoing examples. 5

34. Every novel feature as hereinbefore disclosed or defined in the specification and/or drawings when taken alone or in combination with any other feature including features that are novel or otherwise, including groups of two or more features. 10 N:\Melboume\Cases\Patent\7200O-72999\P72148.AU.2\Specis\P72148.AU.2 Specification tracked 2009-5-21. doc 5/06/09