OA19118A - Procédé et installation de traitement d'un mélange de déchets à deux cycles de compostage. - Google Patents

Abstract

L’invention concerne une installation et un procédé de traitement d’un mélange de déchets (4) comprenant des déchets biodégradables, le procédé étant caractérisé en ce qu’il comporte les étapes successives suivantes : - Etape A : On fait subir un premier cycle de compostage au mélange de déchets (4) de manière à obtenir un mélange de déchets (4) précompostés. - Etape B : On fait subir un séchage au mélange de déchets (4) pré-composté pour obtenir un mélange de déchets (4) séchés. - Etape C : On sépare le mélange de déchets (4) séchés en au moins une portion de déchets lourds (14) et une portion de déchets légers (13). - Etape D : On fait subir un deuxième cycle de compostage à la portion de déchets légers (13) de manière à obtenir un mélange de déchets (4) affinés (20). - Traitement des déchets biodégrables.

Description

PROCESS AND PLANT FOR TREATING A MIXTURE OF WASTE

TWO COMPOSTING CYCLES

TECHNICAL AREA

The present invention relates to the field of waste treatment, in particular the treatment of biodegradable waste for recycling and recovery, especially in the form of compost.

The invention relates more precisely to a process for treating a mixture of waste, the latter being of heterogeneous sizes, shapes and consistencies, the mixture of waste comprising biodegradable waste and non-biodegradable waste.

The invention also relates to an installation for treating a mixture of waste, the latter being of heterogeneous sizes, shapes and consistencies, the waste mixture comprising biodegradable waste and non-biodegradable waste.

PRIOR ART

Traditionally, the recovery of organic waste, generally biodegradable, can be done by composting. Composting embodies the acceleration of the natural process of decomposition of biological and / or organic matter, and makes it possible to transform worthless waste into compost, which is stable, hygienic, rich in humic compounds. The compost can then be used for agriculture, to improve the structure of the soil, and contribute to its fertilization while increasing biodiversity.

On an industrial scale, it is thus possible to carry out the composting of organic waste contained in household waste to allow its recovery, which advantageously makes it possible to avoid their burial or their incineration, these last two solutions being particularly harmful for the environment, and likely to pollute the air and soil.

Nevertheless, known industrial composting processes require sorting of household waste, which contains a very large proportion of waste which is undesirable and unsuitable for composting, such as for example, metals, plastics (including in particular chlorinated plastics such as leI

PVC) and other inert materials, which need to be separated from the household waste mixture.

It is known to ask households generating household waste to sort, or at least pre-sort, their own household waste by themselves. It is therefore necessary to organize a selective collection of waste intended for composting, and of other waste, for example intended for recycling, incineration or landfill. However, despite the growing awareness of households with regard to sorting and its beneficial consequences for the environment, sorting or pre-sorting cannot, in most cases, be considered reliable. Indeed, households or communities may be unable to sort waste properly, which in particular requires suitable infrastructure (several waste collection bins, the organization of selective collection), sometimes expensive, cumbersome , and generate additional traffic. In addition, households may not be able to sort properly, for example by ignorance of the precise nature of the waste and the possible possibilities of recycling it, or by an unwillingness to sort.

Most of the time, it is therefore necessary to sort the waste again before industrial composting, in order to extract a portion which is actually suitable for composting, which is particularly difficult and costly, due to the very nature of the waste, which are very heterogeneous, and mixed. It is particularly difficult | extract the organic compost matter it contains from a waste mixture, because | the latter is generally sticky, dirty, carrying diseases and nauseating.>, i i. . 3 '

Ultimately, in practical terms, most of the waste that can be composted is actually incinerated or buried.

STATEMENT OF THE INVENTION

The objects assigned to the present invention therefore aim to remedy the various drawbacks listed above and to propose a new method and a new installation for treating a mixture of waste making it possible to recover a very large portion of the mixture of waste, in particular n '' having little or no previous sorting.

Another object of the invention is to propose a new process and a new installation for processing a mixture of waste making it possible to selectively recover one or more portions of the mixture of waste despite the heterogeneity of said mixture of waste.

Another object of the invention is to propose a new process and a new installation for treating a mixture of wastes making it possible to produce refined wastes, of the compost type, of good quality from the mixture of wastes.

Another object of the invention is to propose a new process and a new installation for treating a mixture of wastes which are low in pollution and have no negative impact on the environment.

Another object of the invention is to propose a new process and a new installation for treating a mixture of waste whose consumption of resources and energy is particularly low.

Another object of the invention is to propose a new process and a new installation for processing a mixture of waste being inexpensive and easy to implement.

Another object of the invention is to propose a new process and a new installation for treating a mixture of waste which makes it possible to reduce the amount of infrastructure for collecting and treating municipal waste.

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Another object of the invention is to propose a new process and a new installation for processing a mixture of waste, making it possible to simplify the organization of waste collection by communities, businesses and households.

Another object of the invention is to propose a new process and a new installation for treating a mixture of waste allowing treatment of the mixture of waste in a majority, or even fully automated manner.

The objects assigned to the invention are achieved using a process for treating a mixture of waste, the latter being of heterogeneous sizes, shapes and consistencies, the mixture of waste comprising biodegradable waste and waste non-biodegradable, the process being characterized in that it comprises the following successive stages:

Step A: the waste mixture is subjected to a first composting cycle so as to at least partially compost the biodegradable waste from said waste mixture, and to obtain a mixture of pre-composted waste,

- Step B: the mixture of pre-composted waste is subjected to drying in order to obtain a mixture of dried waste,

- Step C: the mixture of dried waste is separated into at least a portion of heavy waste and a portion of light waste, the portion of heavy waste being formed by waste of higher density than the waste | of the portion of light waste, J

- Step D: the waste portion is subjected to a second composting cycle | light so as to at least partially compost the biodegradable waste it contains, and to obtain a mixture of refined waste.

The objects assigned to the invention are also achieved by means of an installation for treating a mixture of wastes, the latter being of heterogeneous sizes, shapes and consistencies, the mixture of wastes comprising biodegradable wastes and non-biodegradable waste, the installation being characterized in that it comprises;

at least one first composting berry allowing the waste mixture to undergo a first composting cycle so as to at least partially compost the biodegradable waste from said waste mixture, and to obtain a mixture of pre-composted waste,

- at least one drying rack for the mixture of pre-composted waste, making it possible to obtain a mixture of dried waste,

means for separating the mixture of dried waste at least into a portion of heavy waste and a portion of light waste, the portion of heavy waste being substantially formed by waste of higher density than the waste of the portion of light waste ,

- At least a second composting berry allowing a portion of light waste to undergo a second composting cycle so as to at least partially compost the biodegradable waste it contains, and to obtain a mixture of refined waste.

SUMMARY OF DRAWINGS

Other features and advantages of the invention will appear and become more apparent on reading the description given below, with reference to the appended drawings, given solely by way of illustrative and nonlimiting example, in which:

- Figure 1 is an oriented tree representing the different stages of the treatment process of a waste mixture according to the invention, as well as their temporal sequence, including in particular steps A, B, C and D of said treatment process.

- Figure 2 is an oriented tree representing in more detail the progress of step C of Figure 1.

- Figure 3 illustrates, along a side, a longitudinal section of a separation means including a ballistic carpet separator, belonging to the installation for processing a mixture of waste according to the invention.

- Figure 4 shows, in a perspective view, the separation means of Figure 3.

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- Figure 5 illustrates, in a perspective view, a longitudinal section of a drying / composting bay belonging to the processing installation of Figures 3 and 4.

BEST WAY TO IMPLEMENT THE INVENTION

The invention relates to a process for treating a mixture of waste 4, aimed at refining, recovering and / or recycling all or part of the latter, and in particular the biodegradable waste which it contains.

The waste mixture 4 is preferably formed by household waste, but can also be formed by waste from economic or industrial activities, or both, said waste having not undergone any sorting or prior grinding.

This mixture of waste 4 is thus advantageously formed of waste generated by households, during consumption and in their daily life. |

Preferably, the waste mixture 4 has not undergone any treatment and forms a mixture | 4 gross waste. In particular, no grinding of the mixture of | raw waste, or any pre-sorting aimed at segregating one type of waste from another, and in particular at carrying out a separation of biodegradable waste and non-biodegradable recyclable waste. Preferably, the waste mixture 4 has been collected, for example using garbage trucks, [from households and / or economic activities without said households and / or | the said economic activities have previously sorted or selected the waste | collected. In particular, the collection of the waste mixture 4 was not selective.

Thus, according to a particularly advantageous variant of the invention, the method of the invention is a method of treating a mixture of raw unmilled waste.

According to the invention, the treatment method is thus characterized in that the waste mixture 4 has not undergone any treatment and forms a raw waste mixture 4, on which in particular no grinding has been carried out, nor no pre-sorting aimed at segregating one type of waste from another, and

...... 'in particular to separate biodegradable waste from non-biodegradable recyclable waste.

Of course, without departing from the scope of the invention, the waste mixture 4 may on the contrary have been stripped of a portion of the recyclable waste which it contains, for example by households during a pre-sorting , or have been the subject of a pre-sorting, for example by households.

The waste of the waste mixture 4 is advantageously collected in a raw and undifferentiated manner, mixed in bags, such as plastic trash bags closed by households, the method comprising a preliminary step of opening said bags in order to release the waste they contain individually to form the waste mixture 4 used in the process of the invention, which is a grouping of the waste initially contained in said bags. The opening of the bags of waste can be carried out for example using a bag opening device, to allow the release of the waste out of said bags, preferably without damaging or altering said waste.

In particular due to the absence of pre-sorting before the entry of the waste mixture 4 into the treatment process of the invention, the waste is of heterogeneous sizes, shapes and consistencies, preferably of nature and origin varied. The waste mixture 4 thus considered may in particular include both soft, hard, sharp, liquid, powdery, solid, flat, hollow, solid, sticky, slippery, fatty, brittle, flexible, compressible, incompressible, combustible, non-combustible waste. or combining several of these characteristics. The waste mixture 4 mainly contains used and undesirable elements, for example food waste, newspapers, paper, cardboard, glass, plastic, metal, textiles, various fuels and incombustibles, complex materials , household hazardous waste, inert waste, bulky items.

According to the invention, the waste mixture 4 comprises biodegradable waste and non-biodegradable waste, the biodegradable waste advantageously forming a non-negligible portion of the waste mixture 4.

. 8 ~ <Advantageously, at least 10%, preferably at least 20%, of the mass of the waste mixture 4 is formed by biodegradable waste, and at least 10%, preferably at least 20%, of the mass of the mixture is formed by non-biodegradable recyclable waste.

Preferably, a non-negligible portion of the mass of the waste mixture 4 is formed by biodegradable waste, for example at least 50% of the mass of the waste mixture, or even at least 60%, or even at least 80%. Preferably, a non-negligible portion of the mass of the waste mixture 4 is itself formed by non-biodegradable recyclable waste.

For the purposes of the invention, the term "biodegradable waste" means waste which, under | the action of a natural environment, comprising for example living organisms and / or air and / or water, can naturally and spontaneously decompose into various elements liable to damage the natural environment (high oxygen demand , emission of leachate) if they have not been stabilized, for example by composting. Living organisms can in particular be formed by microorganisms such as bacteria, fungi or algae, which are capable of degrading biodegradable waste using biochemical reactions. The term “biodegradable waste” is preferably understood to mean waste which can be degraded in this way over the time scale of a human life, of a decade, or more preferably of a year or a few months, preferably of a few weeks. The term “biodegradable waste” is preferably understood to mean waste capable of being used in the manufacture and formation of compost by composting the latter.

"Non-biodegradable" waste, within the meaning of the invention, forms the other waste, which does not spontaneously and naturally undergo such degradation, or which undergo it too slowly. “Non-biodegradable” waste is in | particular unsuitable to enter compost formation by composting these | last. i £ A "recyclable" waste, within the meaning of the invention, forms a waste that can be easily transformed, for example chemically or mechanically, to form a waste i

i recycled material similar to a raw material, which can be used, for example, in the manufacture of an object. The term "recyclable waste" preferably excludes biodegradable waste, even if their transformation into compost gives them in practice a recyclable character. Within the meaning of the invention, recyclable waste may include, for example:

- non-metallic waste, in particular polymers, glass, paper, cardboard, newspapers, rubble, wood, textiles, electronics, etc.

- metallic waste, formed by all types of metals.

For the purposes of the invention, the term "non-recyclable waste" refers to any waste that does not fall into the categories described above of "recyclable waste" and "biodegradable waste". In particular, non-recyclable waste includes in particular waste with a calorific value which makes it liable to be transformed into solid recovery fuel, and other unusable final waste (complex waste, etc.) intended for landfill or incineration.

The treatment process of the invention thus aims to recover the mass of mixed waste forming the waste mixture 4, and in particular to convert in particular the biodegradable waste it contains into a mixture of refined waste 4 20, so that preferably, the refined waste mixture 4 forms compost. Preferably, the mixture of refined waste 4 forms compost satisfying standard NF U 44-051. The NF U 44-051 standard of 2006, called "Organic Amendments - Designations, Specifications and Marking", is a French standard.

According to an important characteristic of the invention, the treatment method comprises the following successive steps:

Step A: the waste mixture 4 is subjected to a first composting cycle so as to at least partially compost the biodegradable waste from said waste mixture 4, and to obtain a pre-composted waste mixture 4,

- Step B: the mixture of pre-composted waste 4 is dried to obtain a mixture of dried waste 4,

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Step C: the mixture of dried waste 4 is separated into at least a portion of heavy waste 14 and a portion of light waste 13, the portion of heavy waste 14 being formed by waste of higher density than the waste of the portion of light waste 13,

- Step D: the portion of light waste 13 is subjected to a second composting cycle so as to at least partially compost the biodegradable waste that it contains, and to obtain a mixture of refined 4 waste 20.

The treatment method of the invention includes the treatment of the waste mixture 4 by two successive composting cycles separated by a step of drying the waste mixture 4 at the end of the first composting cycle to facilitate separation and refining waste mixture 4 easier. Thus, even if waste mixture 4 is particularly heterogeneous and has many undesirable elements which cannot be treated by composting, it is possible to refine the latter using the | process of the invention to obtain refined waste 20 whose value is greater than that of the initial waste mixture. |

Advantageously, the process is an industrial process in which the steps are carried out in a chain and in parallel with one another. For example, while a first waste mixture 4 undergoes step A, another waste mixture 4 simultaneously undergoes step B when it has already undergone step A beforehand.

For the purposes of the invention, the term “composting” means a biological process for the conversion and recovery of organic waste, and in particular biodegradable wasteΓ contained in the waste mixture 4, by promoting and / or | accelerating the natural process of biodegradation. The composting cycles of the process of the invention preferably make it possible to convert at least a portion of the initial waste mixture 4 into a stabilized, hygienic product, rich in humic compounds, preferably in compost. The term “composting” means traditional or industrial composting, for example implementing an action of microorganisms to degrade and putrefy waste from the waste mixture 4, j these microorganisms being naturally present in the waste mixture 4j and / or added to the waste mixture 4, and / or caused to multiply in the mixture | of waste 4. The composting of the invention implements in particular aeration [. .

of the waste mixture 4, and / or a regulation of the humidity of the waste mixture 4 (for example by adding water to the waste mixture 4 and / or by reintroduction into the waste mixture 4 of composting juice 11 emitted by the latter), and / or an addition of microorganisms to the waste mixture 4 and / or an addition of structuring agents 17 to stimulate the composting process, and / or an addition of light, for example solar.

Preferably, step A corresponds to, or comprises, a phase of degradation of waste, in particular biodegradable, while step C corresponds to, or comprises, a phase of maturation of waste, in particular biodegradable, to obtain the mixture of waste 4 matured 20, the latter advantageously forming compost. The degradation phase advantageously results in a proliferation of microorganisms in the waste mixture 4, while the maturation phase preferentially results in a progressive decrease in the quantity of microorganisms that have proliferated during the degradation phase, and the conservation of beneficial microorganisms for soils. The phases of degradation and maturation can overlap or even be confused.

According to the invention, during step A, the first composting cycle allows the composting of the biodegradable portion of the waste mixture 4, while, of course, the non-biodegradable waste remains substantially unaltered, and is used in particular for structuring 17 to the composting process, structuring waste 17 being dedicated in particular to improving the circulation of air within the mixture of waste 4 during composting, in order to improve aerobic composting.

The first composting cycle in step A, like the second composting cycle in step D, is advantageously carried out aerobically. For this, the mixture of waste 4 to be composted is preferably aerated, in particular by means of a circulation of an air flow passing through the mixture of waste 4 to be composted, or by riddling the mixture of waste 4.

A light source 5 is preferably provided to the waste mixture 4 to improve its composting, for example a natural light source 5, and / or an artificial light source 5.

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Advantageously, during step A and / or step D and / or step B, the waste mixture 4 concerned is placed in a heap which is returned several times, for example to the 'Using a suitable loader 1, to help aerate the waste (as illustrated for example in Figure 5). Preferably, during step A, the waste mixture 4 is placed in at least a first composting bay 3, for example in a heap. Also preferably, during step D, the waste from the portion of light waste 13 is disposed in at least one second composting bay 3.

Preferably, during step A, and / or during step D, the waste mixture 4 concerned is humidified using humidity sources 6, the humidity sources 6 being by example formed by watering devices or watering booms with which the first and / or second compost bays are equipped, the heaps being intended to be watered by the watering devices, said watering devices being for example arranged at the above said heaps.

This advantageously operates a regulation of the humidity of the composting mixture during the composting cycles.

The process advantageously includes a step Y during which we recover composting juices 11 seeping from the waste mixture to supply the sources of humidity 6.

Preferably step Y can also include a collection of rainwater to supply the humidity sources 6, which in particular makes it possible to reduce the possible consumption of running water, in particular drinking water, of the process.

Preferably, prior to step A, the method comprises a step 1 during which a second fraction of waste whose size is greater than 110 mm is separated from the waste mixture 4. Larger waste was therefore advantageously separated from the waste mixture 4 using a sorting machine of the rotary trommel type. In particular, the waste from the second fraction of waste has a lower density compared to the waste remaining in the waste mixture 4. Such segregation in particular makes it possible to increase the. 13 τ -, '% concentration of the waste mixture 4 in biodegradable waste, by separating the more massive waste from the initial waste mixture 4. The term “size” of a waste is understood to mean a geometric dimension characteristic of the individual waste, which allows it for example to pass through a mesh of corresponding size if the size of the waste is less than the size of the mesh, or on the contrary not to pass if the size of said waste is greater than the size of said mesh.

Preferably, before step A, and in particular after step 1, the waste mixture 4 contains a majority proportion of wet and / or sticky waste, formed in particular by biodegradable waste, or at least suitable for composting. Their sticky and / or wet nature advantageously facilitates their separation from the second fraction of waste by the sorting machine.

Preferably, prior to step A, the method comprises a step Z during which metallic waste 16 contained in the waste mixture 4 is separated, for example using an electromagnetic separator and / or d 'an eddy current separator, so as to separate at least the majority of said metallic waste 16 contained in the waste mixture 4. The waste mixture 4 intended for the first composting cycle is thus devoid of most of the metallic waste 16 that it contained, and in particular those whose size and / or mass is large, so that the composting process of the first composting cycle is favored and accelerated. The metallic waste 16 thus separated in step Z can advantageously be the subject of a recycling step W.

According to the invention, step B, carried out after step A for the waste mixture 4 considered, makes it possible to remove all or part of the moisture 6 from the waste mixture 4 precomposted during said step A. As 'illustrated in Figure 5, to do this, the mixture of waste 4 pre-composted for example arranged in heaps in at least one, if not more, drying bays, and subjected to drying. Step B preferably comprises a sub-step B1 of circulating a flow of drying air A _S ech through said mixture of pre-composted waste 4 to dry the latter, the flow of drying air A _is ch preferably passing through the heap of waste right through. The drying air A _seC h is advantageously formed by a stream of dry air and heated to a temperature between 40 ° C and 90 ° C, preferably 70 ° C, and which is of a nature. ·; _ · - --- - 14 -.

to entrain, during its passage through the mixture of pre-composted waste 4, the humidity 6 contained in the latter. Preferably, the circulation of the air flow drying Asech takes place vertically, preferably from top to bottom, or otherwise from bottom to top. Thus, we generate an air intake 8 drying under the pile of pre-composted waste.

□ _e preferably, to implement step B, the mixture of precomposted waste 4 is placed in a heap in drying bays, for example on the floor of the latter. To contribute to the drying of said mixture of pre-composted waste 4, the method comprises turning the heap one or more times.

Preferably, and with the aim of saving natural resources, at least a portion of the moisture 6 contained in the mixture of waste 4 pre-composted during stage B is recovered, and the sources d humidity 6 with the portion of humidity 6 thus recovered.

Preferably, the moisture 6 of the mixture of pre-composted waste 4 is thus removed from the latter during step B to be then reintroduced into the portion of | light waste 13 from stage D, so that this moisture is not wasted, and is reused, at least in part. |

In particular, all or part of the composting juices 11 emanating from the | mixture of waste 4 pre-composted during drying, for example by draining the latter using a drainage means 9 from the drying rack 2. These composting juices 11 are advantageously stored, and transported to be reintroduced later in the implementation of first and second composting cycles. Composting juices 11 comprising in particular water, microorganisms and other elements useful for the smooth running of composting, their reintroduction by means of humidity sources 6 into a mixture of waste 4 to be composted allows a improved composting of the latter while reducing the need to bring water, microorganisms and other elements useful to the composting process from outside. !

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Advantageously, the drying air A _S a _C h is put into circulation at least using an air blower 7 carried out above the waste mixture 4, so that the air | drying A _seC h drains the moisture 6 from the mixture of pre-composted waste 4, the step of recovery of the moisture portion being carried out at least in part by condensation of the moisture 6 coming from the mixture of waste 4 pre -composted and drained by the Asech drying air flow In this case, each drying rack 2 also preferably includes means for circulating Asech drying air through the waste mixture 4 to dry it , the means of putting into circulation including at least:

- air blowing means 7 above the mixture of precomposted waste 4, f

- air suction means 8 drying below the mixture of pre-composted waste 4.

In addition, each drying rack 2 advantageously comprises a recuperator 10 of a portion of the moisture 6 contained in the mixture of waste 4 pre-composted during the drying of the latter, the recuperator 10 of moisture making it possible to supply the sources of humidity 6 with the humidity 6 recovered during the drying of said precomposted waste.

j Preferably, the drying air stream A _seC h having circulated through the j i i mixture of pre-composted waste 4 is treated in order to discharge it appreciably from any i emitting composting, in particular odorous, using for example d 'filtering, or [i biochemical treatment. For this purpose, the drying bay (s) includes | preferably means for treating the drying air A _seC h having circulated through the mixture of pre-composted waste 4 in order to discharge it substantially from any composting emission, in particular odorant. In general, the air and possible pollutant emissions linked to the implementation of the treatment process are advantageously treated in this way, which allows the process to be substantially non-polluting and not to generate odors.

Advantageously, at the end of step B and prior to step C, said method comprises a step E during which the mixture is separated from. ____ - waste 4 dried a portion of waste whose size is greater than about 30 mm, called structuring waste 17, whether or not biodegradable waste, composted or not, and the concentration of structuring waste 17 is adjusted by one second waste mixture 4 undergoing step A by adding thereto the portion of structuring waste 17 thus separated from the dried waste mixture 4, so as in particular to structure and seed the first composting cycle. The separation of the structuring waste 17 is advantageously carried out using a rotary trommel whose mesh allows the segregation of objects whose size is greater than approximately 30 mm, and of objects whose size is less than approximately 30 mm . The structuring waste 17 of the dried waste mixture 4 is thus advantageously reused to improve a first composting cycle in progress or later of another waste mixture 4. In this way, it is not or little necessary to add, for the first composting cycle, structuring agents 17 coming from a source external to the treatment process. A more or less large portion of the structuring waste 17 recovered in the waste mixture 4 undergoing step A is advantageously reintroduced so as to adjust, by adding up, the concentration of structuring 17 of said waste mixture 4 up to a predetermined value, preferably suitable for improving the first composting cycle. The recovered structuring waste 17 which is not reintroduced may preferably be sorted, for example manual or using a machine of the rotary trommel type, so as to separate recyclable waste, which the non-recyclable waste is recycled and subjected to a stage X of manufacturing solid recovery fuel (CSR), or another type of reprocessing of the landfill or incineration type. Indeed, it is possible, at this stage of the process, to consider bringing a portion of the mixture of dried waste 4 into step X of manufacturing solid recovery fuel, as long as the waste is dried enough dry, and in particular with an intrinsic humidity of less than about 10%.

According to the invention, all or some of the elements undesirable to the formation of the final refined waste mixture are separated during step C. This separation is facilitated by the fact that, at this stage of the process, all or some of the biodegradable waste has undergone the first composting cycle, so as to be composted, at least partially, and that these same biodegradable waste are dry, and therefore in particular, - ~.

non-sticky, disseminated in the form of powder or pre-compost gravel which adheres less significantly to non-biodegradable waste. This pre-composted and dry biodegradable waste, moreover, advantageously has, for most of them, a low density which is distinct from the rest of the waste of the dried waste mixture 4. Thus, during step C, the portion of light waste 13 comprises a majority concentration of biodegradable waste capable of being transformed into compost. It is thus easier to make a selection of the waste likely to form the mixture of refined waste 4 from the waste mixture 4, which was initially relatively heterogeneous.

Step C and step E are preferably carried out using means for separating the mixture of waste waste 4 dried at least into a portion of heavy waste 14 and a portion of light waste 13, the portion of heavy waste 14 being substantially formed by higher density waste than the waste from the light waste portion 13. The separation means advantageously also include the trommel associated with step E. The trommel associated with step E may optionally be equipped with 'A brush for cleaning the portion of light waste 13 by rubbing, in order to separate the above-mentioned waste.

Preferably, the portion of light waste 13 separated during step C has a density of less than approximately 0.7 kg / L, preferably less than approximately 0.6 kg / L, the dry compost generally having a mass volume close to 0.5 kg / L. Plastics most often having a density greater than 0.8 kg / L can thus easily be separated from the portion of light waste 13. It is thus advantageous to separate from the portion of light waste 13 plastics, including the materials chlorinated plastics such as polyvinyl chloride (PVC), so that the mixture of waste 4 refined 20 will be substantially free of it at the end of step D, or will be provided in negligible proportions. For example, gravel and other stones, metals, glass, degraded or degrading paper fibers can also be separated during step C, so that the mixture of refined waste 4 will be substantially free of it. at the end of step D, or will be provided in negligible proportions.

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As illustrated in FIG. 2, step C preferably comprises a first substep C1 during which the residual waste metal 4 is separated from the residual metallic waste 16 which it contains, for example using an electromagnetic separator and / or an eddy current separator, so as to separate at least the majority of the residual metallic waste 16 contained in said mixture of dried waste 4. This advantageously separates again any ferrous (using the magnetic separator) and non-ferrous metallic element (using the eddy current separator) contained in the mixture of dried waste 4, which would in particular not have been separated during step Z. The “dried” state of the waste advantageously facilitates such separation. This first sub-step C1 preferably contributes to the formation of a mixture of good quality refined waste 4, and in particular of a compost satisfying standard NF U 44-051. The treatment method thus preferably comprises a step W of recycling the metallic waste 16 initially contained in the waste mixture 4. The sub-step C1 is preferably carried out before the separation of the heavy waste and the light waste.

Stage C preferably comprises a second sub-stage C2, during which the mixture of dried waste 4 is separated, in addition to the portion of heavy waste 14 and light waste 13, into a portion of intermediate waste 19 whose density is intermediate, that is to say between the density of the waste of the first and second portions of waste, and that said portion of intermediate waste 19 is added to the waste mixture 4 undergoing step A. intermediate waste 19, whose density is for example greater than approximately 0.6 kg / L but less than approximately 0.7 kg / L, is preferably returned in a first composting cycle in accordance with step A. In fact, it is possible that intermediate waste 19 could be formed by biodegradable waste whose degradation of the first composting cycle would be incomplete, or whose drying would be incomplete. This second sub-step C2 thus makes it possible to improve the separation between the waste which will enter into the composition of the mixture of refined waste 4, and the other waste.

The second sub-step C2 is preferably carried out after sub-step C1, and contributes to the separation of heavy waste and light waste.

19118 ι

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Step C, the first substep C1 and the second substep 02 are advantageously carried out at least using the above-mentioned separation means, comprising in particular a ballistic belt separator 12 (as illustrated for example in the figures 3 and 4) and an associated densimetric table separator. In this case, the method preferentially implements a first ballistic mat 12A making it possible to separate first the portion of heavy waste 14, the rest of the mixture of dried waste 4 being directed towards a second ballistic mat 12B making it possible to separate a portion of light waste 13 and a portion of indeterminate waste 15. The portion of indeterminate waste is advantageously directed towards the densimetric separator, which makes it possible to separate the portion of indeterminate waste more finely, in particular by separating light waste joining the portion of light waste , heavy waste joining the portion of heavy waste 14, and ia portion of intermediate waste 19 described above.

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As shown in Figures 3 and 4, the first and second ballistic belts 12A, 12B are preferably included in the same machine, as illustrated

I in the figures, the first ballistic mat 12A directly supplying the second ballistic mat 12B by gravity. An accelerator belt can advantageously be placed upstream of the first ballistic belt 12A so as to accelerate the mixture of dried waste 4 in order to project them onto the first ballistic belt 12B with a certain kinetic energy capable of improving the separation of the waste. The first ballistic mat 12A and the second ballistic mat 12B preferably have an inclination in the longitudinal direction, which inclination is adjustable, for example between 20 ° and 70 ° relative to the horizontal, in order to allow the separation of the waste to be adjusted. . To improve the separation, the first and / or the second ballistic carpet 12A, 12B preferably comprises an elastic tread making it possible to rebound and make roll certain types of waste on said tread (in particular the [most massive of them), certain others of the waste being intended on the contrary to [adhere to the tread. The tread can also | advantageously have adhesive or sticky properties, in particular for | adhere your finest waste. The dried waste mixture 4 includes | particularly fines, which can advantageously be recovered to be introduced into the portion of light waste 13, for example by scraping the carpets • 20. ballistics 12 using a tungsten scraper fitted to said ballistic mats (not shown).

At the end of step C, in particular of sub-step C2, and prior to step D, said method preferably comprises a step F during which a portion is separated from the portion of light waste 13 coarse waste 18 whose size exceeds 12 mm, for example using a rotary trommel whose mesh allows the segregation of objects whose size is greater than about 12 mm, and of objects which are smaller about 12 mm. The coarse waste 18 forms, in this case, light waste whose size is too large to be able to enter into the composition of the mixture of refined waste 4, and in particular to form compost meeting the standard NF U 44-051. All or part of this portion of coarse waste 18 is advantageously crushed to be reintroduced into the portion of light waste 13 during step D. Alternatively, all or part of this portion of coarse waste 18 is preferably reintroduced into a mixture of waste 4 undergoing step A. In addition, all or part of this portion of coarse waste 18, which may be formed from non-compostable waste, can enter stage X of manufacturing solid recovered fuel, or make the object, if possible, of the recycling stage W.

Finally, step D of the invention makes it possible to refine the decomposition of the organic waste contained in the initial waste mixture 4. At this stage of the process, the second composting cycle is carried out on the portion of light waste 13, which comes from the initial waste mixture 4, which has been devoid of the vast majority, if not of all of the waste not conforming to the formation of the final refined 4 waste mixture. A mixture of refined waste 4 of good quality is thus obtained, and capable of meeting particular standards. Furthermore, at the end of the treatment process, most, if not all, of the biodegradable waste from the initial waste mixture 4 enters into the composition of the final refined waste mixture 4.

Step D is preferably carried out by placing the portion of light waste 13, for example in a heap, in at least one second composting bay 3, for example similar to the first composting bay 3.

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Step D advantageously comprises at least one sub-step D1 for rehumidifying light waste, for example with the moisture 6 recovered during drying step B, in order to promote natural composting, and in particular the maturation of the compost. during the second composting cycle to form the mixture of refined waste 4 20. Preferably, step D also comprises aeration of light waste, for example similar to step A (using a air flow, or several turns of the light waste pile) to promote the formation of refined waste 20.

Stage D can also preferably include the reintroduction of microorganisms into said light waste, for example originating from the first composting cycle of stage A.

it is thus possible to recover the initial waste mixture 4 into a final refined waste mixture 4, for example forming a compost in accordance with standard NF U 44-051.

The invention also relates, as such, to an installation for treating a mixture of waste 4, the latter being of heterogeneous sizes, shapes and consistencies, the mixture of waste 4 comprising biodegradable waste and non-biodegradable waste, the installation including:

at least a first composting bay 3 allowing the waste mixture 4 to undergo a first composting cycle so as to at least partially compost the biodegradable waste from said waste mixture 4, and to obtain a pre-composted waste mixture 4 ,

- at least one drying rack 2 of the mixture of pre-composted waste 4, making it possible to obtain a mixture of dried waste 4,

means for separating the mixture of waste 4 dried at least into a portion of heavy waste 14 and a portion of light waste 13, the portion of heavy waste 14 being substantially formed by waste of higher density than the waste of the portion of light waste 13,

- at least a second composting bay 3 allowing the portion of light waste 13 to undergo a second composting cycle so as to 'At least partially compost the biodegradable waste it contains, and to obtain a mixture of waste 4 matured 20.

The treatment installation preferably forms a factory making it possible to implement the process described above. Consequently, the elements of this installation, and in particular the first composting bay 3, the second composting bay 3, the drying bay 2, the separation means, advantageously correspond to those described above.

Preferably, the first bay, and / or the second bay, comprise sources of humidity 6 making it possible to humidify the mixture of waste 4 concerned, that is to say respectively the mixture of waste 4 and the portion of waste light 13. d

Advantageously, the drying rack 2 comprises a recuperator 10 of a portion of the moisture 6 contained in the mixture of waste 4 pre-composted during the drying of the latter, the recuperator 10 making it possible to supply the sources of humidity 6 with the humidity 6 recovered during the drying of said precomposted waste.

The recuperator 10 advantageously corresponds to that described above, and comprises for example a device for condensing the humidity 6 contained in the drying air, which has been extracted from the mixture of pre-composted waste 4. The recuperator 10 also includes, for example, a device for draining the composting juices 11, disposed at ground level 12, making it possible to collect and drain said composting juices 11.

Preferably, the drying rack 2 comprises means for circulating air drying Ase _C h through the waste mixture 4 pre-composted to dry the latter, the means for circulating including at least:

- air blowing means 7 above the mixture of precomposted waste 4,

- air suction means 8 drying below the mixture of pre-composted waste 4, arranged for example at ground level 12D, under the pile of pre-composted waste.

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Such an arrangement advantageously makes it possible to create a drying air circulation.

At _seC h from top to bottom suitable for drying the mixture of i pre-composted waste 4.

The condensing device is preferably placed within the means | suction 7 and / or blowing means 8. [i

The drying rack 2 preferably comprises a light source 5 such that | described above, allowing the waste mixture 4 to be irradiated during drying, and | thus facilitating its drying. i

The composting bay 3 advantageously also includes a source of | light 5 for irradiating the waste mixture 4 during composting, and | thus improving the composting of the latter (as illustrated in FIG. 5), natural light, and in particular the sun's rays being conducive to the development of life, and in particular to microorganisms which are sensitive thereto .iij

The light source 5 can advantageously be formed by a canopy placed at | plumb with composting 3 or drying bay 2, allowing light from | protecting the bay from the elements.

Such an arrangement advantageously makes it possible to avoid clogging of the circulation means.

L The installation also advantageously includes air treatment means | drying A _seC h having circulated through the mixture of waste 4 pre-composted for | substantially relieve of any composting emission, in particular odorous, such as [as described for example above. | ! Preferably, the compost bays and the drying bays are identical, and | are combined, to form composting / drying bays and ensure | selectively the two associated functions. Of course, the drying bays and the compost bays can be perfectly separate without departing from the scope of | the invention. i

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- 24. .As described above, the separation means preferably include at least one ballistic belt separator 12 and one associated densimetric table separator making it possible to separate the portion of heavy waste 14 and the portion of light waste 13.

Thanks to such an installation, all or part of the treatment process described above can preferably be carried out in an automated and industrial manner.

POSSIBILITY OF INDUSTRIAL APPLICATION

The invention finds its industrial application in the design, production and implementation of means for processing a mixture of waste of sizes, shapes and heterogeneous consistencies, the mixture comprising biodegradable waste and j non-biodegradable waste . r

Claims (25)

1 - Process for treating a mixture of waste (4), the latter being of heterogeneous sizes, shapes and consistencies, the mixture of waste (4) comprising biodegradable waste and non-biodegradable waste, the process being characterized by what it involves the following successive stages: - Step A: the waste mixture (4) is subjected to a first composting cycle so as to at least partially compost the biodegradable waste from said waste mixture (4), and to obtain a pre-waste mixture (4) composted, - Step B: the mixture of pre-composted waste (4) is subjected to drying in order to obtain a mixture of dried waste (4), - Step C: the mixture of dried waste (4) is separated into at least a portion of heavy waste (14) and a portion of light waste (13), the portion of heavy waste (14) being formed by mass waste higher volume than the waste from the light waste portion (13), - Step D: the portion of light waste (13) is subjected to a second composting cycle so as to at least partially compost the biodegradable waste which it contains, and to obtain a mixture of refined waste (4) (20 ). 2 - Treatment method according to the preceding claim, characterized in that prior to step A, the method comprises a step 1 during which the second waste fraction whose size is greater is separated from the waste mixture (4) at 110 mm. 3 - Treatment method according to any one of the preceding claims, characterized in that, prior to step A, it comprises a step Z during which metallic waste (16) contained in the waste mixture is separated ( 4), for example using an electromagnetic separator and / or an eddy current separator, so as to separate at least the majority of said metallic waste (16) contained in the waste mixture (4). - .. - 26. 4- A treatment method according to any one of the preceding claims, characterized in that during step A, and / or during step D, the waste mixture (4) concerned is moistened using moisture sources (6). 5 - Treatment method according to your previous claim, characterized in that it comprises a step Y during which we recover composting juices (11) seeping from the waste mixture to feed the sources of humidity (6). 6- A treatment method according to any one of claims 4 or 5, characterized in that one recovers a portion of the moisture (17) contained in the mixture of waste (4) pre-composted during the step B, and that the moisture sources (6) are supplied with the portion of the moisture (17) thus recovered. 7 - Treatment method according to any one of the preceding claims, characterized in that step B comprises a sub-step B1 of circulating a flow of drying air (A _seC h) through said mixture of waste (4) precomposted to dry the latter. 8 - Treatment method according to the preceding claim, characterized in that the circulation of the drying air flow (A _sech ) takes place substantially vertically, preferably from top to bottom. 9 - Treatment method according to claim 6 and according to any one of claims 7 or 8, characterized in that one puts the drying air (A _sech ) in circulation at least using a blowing d air (7) carried over the waste mixture (4), so that the drying air (A _secÎ1 ) drains the moisture (17) from the pre-composted waste mixture (4), the recovery step the moisture portion being carried out at least in part by condensation of the moisture (17) coming from the waste mixture (4) pre-composted and drained by the flow of drying air (A _sec h). 27 10 - Treatment method according to any one of claims 7 to 9, characterized in that the drying air stream (Asech) having circulated through the mixture of waste (4) pre-composted is treated to discharge it substantially any composting emission, in particular odorous. 11- Treatment method according to any one of the preceding claims, characterized in that, during step A and / or step D and / or step B, the waste mixture (4) concerned is arranged in a heap which is turned over several times. 12- Treatment method according to any one of the preceding claims, characterized in that, at the end of step B and before step C, said method comprises a step E during which the mixture is separated from the mixture of dried waste (4) a portion of waste whose size is greater than about 30 mm, called structuring waste (17), and the concentration of structuring waste (17) of a second mixture of waste (4) undergoing l is adjusted 'step A by adding the portion of structuring waste (17) thus separated from the mixture of dried waste (4), so as in particular to structure and seed the first composting cycle. 13- Treatment process according to any one of the preceding claims, characterized in that step C comprises a first sub-step C1 during which the residual metal waste (4) is separated from the residual metallic waste (16) that it contains, for example using an electromagnetic separator and / or an eddy current separator, so as to separate at least the majority of the residual metallic waste (16) contained in said waste mixture ( 4) dried. 14- Treatment method according to any one of claims 3 or 13, characterized in that it comprises a step (W) of recycling of the metallic waste (16) initially contained in the waste mixture (4). 28. - 15- Treatment method according to any one of the preceding claims, characterized in that step C comprises a second sub-step C2 during which the mixture of dried waste (4) is separated, in addition to the portion of heavy waste (14) and light waste (13), into a portion of intermediate waste (19) whose density is intermediate, that is to say, between the density of the waste of the first and second portions of waste, and that said portion of intermediate waste (19) is added to the waste mixture (4) undergoing step A. 16- Treatment method according to any one of the preceding claims, characterized in that the portion of light waste (13) separated during step C has a density less than about 0.7 kg / L, preferably less than about 0.6 kg / L. 17- Treatment method according to any one of the preceding claims, characterized in that, at the end of step C and before step D, said method comprises a step F during which the portion of light waste (13), a portion of coarse waste (18) the size of which exceeds 12 mm. 18- Treatment method according to any one of the preceding claims, characterized in that the mixture of refined waste (4) (20) forms compost 19 - Treatment method according to the preceding claim, characterized in that the mixture of waste (4) refined (20) forms compost satisfying standard NF U 44-051. 20 - Treatment method according to any one of the preceding claims, characterized in that the waste mixture (4) has not undergone any treatment and forms a raw waste mixture (4), on which in particular has not been carried out no grinding or any sorting prior to segregating one type of waste from another, and in particular to effect a separation of biodegradable waste and non-biodegradable recyclable waste. 29 'ί 3! E 21 - Installation for processing a mixture of waste (4), the latter being of size, | of heterogeneous shapes and consistencies, the waste mixture (4) comprising biodegradable waste and non-biodegradable waste, the installation being characterized in that it comprises: - At least a first composting berry (3) allowing to subject a first composting cycle to the waste mixture (4) so as to at least partially compost the biodegradable waste from said waste mixture (4), and to obtain a mixture of pre-composted waste (4), - at least one drying bay (2) of the mixture of pre-composted waste (4), making it possible to obtain a mixture of dried waste (4), - means for separating the mixture of waste (4) dried at least into a portion of heavy waste (14) and a portion of light waste (13), the portion of heavy waste (14) being substantially formed by mass waste higher volume than the waste from the light waste portion (13), - at least a second composting berry (3) making it possible to subject a portion of light waste (13) to a second composting cycle so as to at least partially compost the biodegradable waste it contains, and to obtain a mixture refined waste (4) (20). s IE 22 - Treatment installation according to the preceding claim, characterized in that] the first bay, and / or the second bay, comprise sources of humidity (6) J for humidifying the mixture of waste (4) concerned, the drying rack (2) | comprising a recuperator (10) of a portion of the moisture (17) contained in the mixture of waste (4) pre-composted during the drying of the latter, the recuperator (10) making it possible to supply the sources of humidity (6) with the moisture (17) recovered during the drying of said pre-composted waste. i 23 - Treatment installation according to any one of claims 21 or 22, | characterized in that the drying bay (2) comprises means for putting in circulation drying air (A _sech ) through the mixture of waste (4) precomposted to dry the latter, the means for circulating including at minus: ... 30 - air blowing means (7) above the mixture of precomposted waste (4), -air suction means (8) drying below the mixture of pre-composted waste (4). 5 24 - Treatment installation according to claim 23, characterized in that it comprises means for treating the drying air (A _seC h) having circulated through the mixture of waste (4) pre-composted to discharge it substantially from any composting emission, particularly odorous. 25-Treatment installation according to any one of claims 21 to 24, 10 characterized in that the separation means include at least one ballistic belt separator (12) and a densimetric table separator associated for separating the portion of waste heavy (14) and the portion of light waste (13).