NZ727153B2 - Method and installation for treating a mixture of waste, having two composting cycles - Google Patents
Method and installation for treating a mixture of waste, having two composting cycles Download PDFInfo
- Publication number
- NZ727153B2 NZ727153B2 NZ727153A NZ72715315A NZ727153B2 NZ 727153 B2 NZ727153 B2 NZ 727153B2 NZ 727153 A NZ727153 A NZ 727153A NZ 72715315 A NZ72715315 A NZ 72715315A NZ 727153 B2 NZ727153 B2 NZ 727153B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- wastes
- mixture
- composting
- composted
- drying
- Prior art date
Links
- 239000002699 waste material Substances 0.000 title claims abstract description 518
- 239000000203 mixture Substances 0.000 title claims abstract description 291
- 238000009264 composting Methods 0.000 title claims abstract description 113
- 238000000034 method Methods 0.000 title claims abstract description 83
- 238000009434 installation Methods 0.000 title abstract 2
- 239000010815 organic waste Substances 0.000 claims abstract description 53
- 238000000926 separation method Methods 0.000 claims abstract description 25
- 238000001035 drying Methods 0.000 claims description 79
- 239000002361 compost Substances 0.000 claims description 32
- 239000010814 metallic waste Substances 0.000 claims description 19
- 239000010819 recyclable waste Substances 0.000 claims description 12
- 239000010805 inorganic waste Substances 0.000 claims description 10
- 235000011389 fruit/vegetable juice Nutrition 0.000 claims description 9
- 238000007664 blowing Methods 0.000 claims description 8
- 238000000227 grinding Methods 0.000 claims description 5
- 238000004064 recycling Methods 0.000 claims description 5
- 238000005204 segregation Methods 0.000 claims description 5
- 238000009833 condensation Methods 0.000 claims description 4
- 230000005494 condensation Effects 0.000 claims description 4
- 244000005700 microbiome Species 0.000 description 11
- 239000000463 material Substances 0.000 description 10
- 230000015556 catabolic process Effects 0.000 description 8
- 238000006731 degradation reaction Methods 0.000 description 8
- 229920003023 plastic Polymers 0.000 description 7
- 239000004033 plastic Substances 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 239000010791 domestic waste Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 239000003473 refuse derived fuel Substances 0.000 description 5
- 230000035800 maturation Effects 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000003205 fragrance Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000010847 non-recyclable waste Substances 0.000 description 3
- 239000000123 paper Substances 0.000 description 3
- 229920000915 polyvinyl chloride Polymers 0.000 description 3
- 239000002689 soil Substances 0.000 description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 238000009933 burial Methods 0.000 description 2
- 239000011111 cardboard Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 238000005304 joining Methods 0.000 description 2
- 239000010813 municipal solid waste Substances 0.000 description 2
- 239000011368 organic material Substances 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- -1 powdery Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000004753 textile Substances 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- 241000195493 Cryptophyta Species 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005842 biochemical reaction Methods 0.000 description 1
- 238000006065 biodegradation reaction Methods 0.000 description 1
- 239000012620 biological material Substances 0.000 description 1
- 230000031018 biological processes and functions Effects 0.000 description 1
- 239000010782 bulky waste Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011365 complex material Substances 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000004720 fertilization Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000010794 food waste Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- 239000010804 inert waste Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000006148 magnetic separator Substances 0.000 description 1
- 239000010812 mixed waste Substances 0.000 description 1
- 235000019645 odor Nutrition 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000007425 progressive decline Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000035755 proliferation Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/06—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B5/00—Operations not covered by a single other subclass or by a single other group in this subclass
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05F17/00—Preparation of fertilisers characterised by biological or biochemical treatment steps, e.g. composting or fermentation
- C05F17/10—Addition or removal of substances other than water or air to or from the material during the treatment
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05F17/00—Preparation of fertilisers characterised by biological or biochemical treatment steps, e.g. composting or fermentation
- C05F17/50—Treatments combining two or more different biological or biochemical treatments, e.g. anaerobic and aerobic treatment or vermicomposting and aerobic treatment
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05F17/00—Preparation of fertilisers characterised by biological or biochemical treatment steps, e.g. composting or fermentation
- C05F17/90—Apparatus therefor
- C05F17/964—Constructional parts, e.g. floors, covers or doors
- C05F17/971—Constructional parts, e.g. floors, covers or doors for feeding or discharging materials to be treated; for feeding or discharging other material
- C05F17/979—Constructional parts, e.g. floors, covers or doors for feeding or discharging materials to be treated; for feeding or discharging other material the other material being gaseous
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05F17/00—Preparation of fertilisers characterised by biological or biochemical treatment steps, e.g. composting or fermentation
- C05F17/90—Apparatus therefor
- C05F17/964—Constructional parts, e.g. floors, covers or doors
- C05F17/971—Constructional parts, e.g. floors, covers or doors for feeding or discharging materials to be treated; for feeding or discharging other material
- C05F17/986—Constructional parts, e.g. floors, covers or doors for feeding or discharging materials to be treated; for feeding or discharging other material the other material being liquid
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05F17/00—Preparation of fertilisers characterised by biological or biochemical treatment steps, e.g. composting or fermentation
- C05F17/90—Apparatus therefor
- C05F17/989—Flow sheets for biological or biochemical treatment
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05F9/00—Fertilisers from household or town refuse
- C05F9/02—Apparatus for the manufacture
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
- Y02A40/20—Fertilizers of biological origin, e.g. guano or fertilizers made from animal corpses
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/141—Feedstock
- Y02P20/145—Feedstock the feedstock being materials of biological origin
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/40—Bio-organic fraction processing; Production of fertilisers from the organic fraction of waste or refuse
Abstract
The invention relates to an installation and a method for treating a mixture of waste (4) comprising biodegradable waste, the method being characterized in that it comprises the following successive steps: - Step A: the mixture of waste (4) is subjected to a first composting cycle so as to obtain a mixture of pre-composted waste (4), - Step B: the mixture of pre-composted waste (4) is dried after completion of Step A in order to obtain a mixture of dried waste (4), - Step C: the mixture of dried waste (4) is separated into at least one portion of heavy waste (14), and one portion of light waste (13) having a density of less than 0.7 kg/l - Step D: the portion of light waste (13) is subjected to a second composting cycle so as to obtain a mixture of refined waste (4; 20). -The method allows for the separation and treatment of the biodegradeable waste. a mixture of pre-composted waste (4), - Step B: the mixture of pre-composted waste (4) is dried after completion of Step A in order to obtain a mixture of dried waste (4), - Step C: the mixture of dried waste (4) is separated into at least one portion of heavy waste (14), and one portion of light waste (13) having a density of less than 0.7 kg/l - Step D: the portion of light waste (13) is subjected to a second composting cycle so as to obtain a mixture of refined waste (4; 20). -The method allows for the separation and treatment of the biodegradeable waste.
Description
METHOD AND PLANT FOR TREATING A MIXTURE OF WASTES
WITH TWO COMPOSTING CYCLES
TECHNICAL FIELD
The present invention concerns the field of treating wastes, in particular
of treating biodegradable wastes in order to recycle them and valorize them,
particularly in the form of compost.
The invention concerns more specifically a method for treating a mixture
of wastes, the latter being with heterogeneous sizes, shapes and consistencies,
the mixture of wastes comprising biodegradable wastes and non-biodegradable
wastes.
The invention also concerns a plant for treating a mixture of wastes, the
latter being with heterogeneous sizes, shapes and consistencies, the mixture of
wastes comprising biodegradable wastes and non-biodegradable wastes.
PRIOR ART
Conventionally, the recovery of generally biodegradable, organic wastes
can be performed by composting. Composting consists in an acceleration of the
natural process of decomposition of the biological and/or organic material, and
allows transforming worthless wastes into compost, which is stable, hygienic,
rich in humic compounds. The compost can then be used for agriculture, in
order to improve the structure of the soil, and contribute to its fertilization while
increasing biodiversity.
On an industrial scale, it is thus possible to perform the composting of
organic wastes contained in domestic wastes in order to allow their recovery,
which advantageously allows preventing their burial or incineration, the last two
solutions being particularly harmful to the environment, and likely to pollute the
air and soil.
Nevertheless, the known industrial composting methods require a sorting
of domestic wastes, which contain a very significant proportion of wastes which
are undesirable and not suited for composting, such as for example of metals,
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
plastic materials (including in particular chlorinated plastic materials such as
PVC) and other inert materials, that it is necessary to separate from the mixture
of domestic wastes.
It is known to ask households generating the domestic wastes to sort, or
at least pre-sort, their domestic wastes by themselves. Henceforth, it is
necessary to organize a selective collection of the wastes intended to be
composted, and the other wastes intended for example to be recycled, to be
incinerated or to be buried. However, despite the progressive awareness of the
households about sorting and its beneficial consequences on the environment,
most of the time, such a sorting or pre-sorting cannot be considered to be
reliable. Indeed, the households or the communes may be unable to sort the
wastes in a proper way, which requires in particular adapted infrastructures
(several bins for collecting wastes, the organization of a selective collection),
sometimes expensive, bulky, and generating an additional traffic. Furthermore,
the households may be unable to perform sorting in a correct way, for example
by ignoring the exact nature of the wastes or the possibilities of valorizing the
latter, or still by lack of willingness to perform the sorting.
Most of the time, it is thus necessary to sort the wastes again before their
industrial composting, in order to extract therefrom a portion effectively suitable
for composting, which is particularly difficult and expensive because of the very
nature of wastes, which is very heterogeneous, and mixed. It is in particular
difficult to extract the organic material to be composted from the mixture of
wastes contained therein, as the latter is generally sticky, dirty, disease carrier
and smelly.
In fine, in practice, most of the wastes which may undergo a composting
are actually incinerated or buried.
All references, including any patents or patent applications cited or
mentioned in this specification are hereby incorporated by reference. No
admission is made that any reference constitutes prior art. The discussion of the
references states what their authors assert, and the applicants reserve the right
to challenge the accuracy and pertinency of the cited documents. It will be
clearly understood that, although a number of prior art publications may be
referred to herein; this reference does not constitute an admission that any of
these documents form part of the common general knowledge in the art, in
Australia, New Zealand or in any other country.
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide an improved method
and plant for treating a mixture of wastes with two composting cycles that
ameliorates some of the disadvantages and limitations of the known art or at
least provide the public with a useful choice.
Consequently, the objects assigned to the present invention aim to
remedy to the different drawbacks enumerated hereinbefore and to propose a
new method and a new plant for treating a mixture of wastes allowing valorizing
a very considerable portion of the mixture of wastes, in particular which have
not been or a little subjected to a prior sorting.
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes allowing valorizing selectively one or
several portion(s) of the mixture of wastes despite the heterogeneity of said
mixture of wastes.
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes allowing producing refined wastes, of the
compost kind, of good quality from the mixture of wastes.
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes being low-pollutant and without negative
impact on the environment.
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes with a particularly low consumption of
resources and energy.
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes which are inexpensive and easy to
implement.
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes allowing reducing the number of
infrastructures for collecting and treating wastes of communes.
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes allowing simplifying the organization of
collection of wastes by communes, businesses and households.
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Another object of the invention aims to propose a new method and a new
plant for treating a mixture of wastes allowing a treatment of the mixture of
wastes in an almost, still fully, automated way.
The objects assigned to the invention are achieved by means of a
method for treating a mixture of wastes (4), the latter being with heterogeneous
sizes, shapes and consistencies, the mixture of wastes (4) comprising
biodegradable wastes and non-biodegradable wastes, the method wherein it
includes the following successive steps:
Step A: the mixture of wastes (4) is subjected to a first composting
cycle so as to compost, the biodegradable wastes of said mixture of wastes,
and to obtain a mixture of pre-composted wastes (4),
Step B: upon completion of the first composting cycle, the mixture
of pre-composted wastes (4) is subjected to a drying so as to obtain a mixture
of dried wastes (4),
Step C: the mixture of dried wastes (4) is separated into one
portion of heavy wastes (14) and one portion of light wastes (13), the portion of
heavy wastes (14) being formed by wastes with a volumetric mass heavier than
the wastes of the portion of light wastes (13), the portion of light wastes (13)
having a density less than about 0.7 kg/L.
Step D: the portion of light wastes (13) is subjected to a second
composting cycle so as to compost, at least partially, the contained
biodegradable wastes, and to obtain a mixture (4) of refined wastes (20).
Preferably, prior to step A, the method includes a step 1 during which a
second fraction of wastes the size of which is larger than 110 mm is separated
from the mixture of wastes (4).
Preferably, prior to step A, it includes a step Z during which metal wastes
(16) contained in the mixture of wastes (4) are separated, for example by
means of an electromagnetic separator and/or an eddy current separator, so as
to separate at least most of said metal wastes (16) contained in the mixture of
wastes (4).
Preferably, during step A, and/or during step D, the concerned mixture of
wastes (4) is moistened by means of moisture sources (6).
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Preferably it includes a step Y during which composting juices (11)
oozing from the mixture of wastes are retrieved for supplying the humidity
sources (6).
Preferably a portion of the moisture (17) contained in the mixture of pre-
composted wastes (4) during step B is retrieved, and in that the humidity
sources (6) are supplied with the portion of the moisture (17) retrieved
accordingly.
Preferably step B comprises a substep B1 of circulating a drying air flow
(Adry) through said mixture of pre-composted wastes (4) in order to dry the
latter.
Preferably the circulation of the drying air flow (Adry) is performed
substantially vertically, preferably from top to the bottom.
Preferably the drying air (Adry) is circulated at least by means of an air
blowing (7) performed above the mixture of wastes (4), so that the drying air
(Adry) drains moisture (17) from the mixture of pre-composted wastes (4), the
step of retrieving the portion of moisture being carried out at least partly by
condensation of moisture (17) coming from the mixture of pre-composted
wastes (4) and drained by the drying air flow (Adry).
Preferably the drying air flow (Adry) having circulated through the mixture
of pre-composted wastes (4) is treated to substantially discharge it from any
composting, in particular odorous, emission.
Preferably, during step A and/or step D and/or step B, the concerned
mixture of wastes (4) is disposed in a heap which is turned over several times.
Preferably, at the end of step B and prior to step C, said method includes
a step E during which, is separated from the mixture of dried wastes (4), a
portion of wastes the size of which is larger than about 30 mm, called
structurant wastes (17), and the concentration of structurant wastes (17) of a
second mixture of wastes (4) subjected to step A is adjusted by adding therein
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
the portion of structurant wastes (17) thus separated from the mixture of dried
wastes (4), so as in particular to structure and seed the first composting cycle.
Preferably step C comprises a first substep C1 during which is separated
from the mixture of dried wastes (4), residual metal wastes (16) contained
therein, for example by means of an electromagnetic separator and/or an eddy
current separator, so as to separate at least most of the residual metal wastes
(16) contained in said mixture of dried wastes (4).
Preferably it comprises a step (W) of recycling metal wastes (16) initially
contained in the mixture of wastes (4).
Preferably step C comprises a second substep C2 during which, besides
the portion of heavy wastes (14) and light wastes (13), the mixture of dried
wastes (4) is separated from a portion of intermediate wastes (19) the density of
which is intermediate, that is to say comprised between the density of the
wastes of the first and second portions of wastes, and during which said portion
of intermediate wastes (19) is added in the mixture of wastes (4) subjected to
step A.
Preferably the portion of light wastes (13) separated during step C has a
density less than about 0.6 kg/L.
Preferably, upon completion of step C and prior to step D, said method
includes a step F during which is separated from the portion of light wastes (13),
a portion of coarse wastes (18) the size of which exceeds 12 mm.
Preferably the mixture of refined wastes forms the compost.
Preferably the mixture (4) of refined wastes (20) forms the compost
meeting the standard NF U 44-051 of 2006.
Preferably the mixture of wastes (4) has not been subjected to any
treatment and forms a raw mixture of wastes (4), on which in particular neither
grinding has been carried out, nor prior sorting aiming to perform a segregation
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
of one type of waste relative from another, and in particular to perform a
separation of biodegradable wastes and non-biodegradable recyclable wastes.
The objects assigned to the invention can also achieved by means of a
plant for treating a mixture of wastes (4), the latter being with heterogeneous
sizes, shapes and consistencies, the mixture of wastes (4) comprising
biodegradable wastes and non-biodegradable wastes, the plant being
characterized in that it comprises:
at least one first composting bay (3) allowing subjecting the
mixture of wastes (4) to a first composting cycle so as to compost, at least
partially, the biodegradable wastes of said mixture of wastes, and to obtain a
mixture of pre-composted wastes (4),
at least one bay (2) for drying the mixture of pre-composted
wastes (4), allowing obtaining a mixture of dried wastes (4), said bay (2) for
drying being designed for drying said mixture of pre–composted wastes (4)
upon completion of the first composing cycle, allowing obtaining a mixture of
dried wastes (4),
means for separating the mixture of dried wastes (4) at least into a
portion of heavy wastes (14) and a portion of light wastes (13), the portion of
heavy wastes (14) being substantially formed by wastes with a volumetric mass
heavier than the wastes of the portion of light wastes (13), the portion of light
wastes (13) having a density less than about 0.7 kg/L,
at least one second composting bay (3) allowing subjecting the
portion of light wastes (13) to a second composting cycle so as to compost, at
least partially, the contained biodegradable wastes, and to obtain a mixture (4)
of refined wastes (20),
wherein the separation means include a ballistic belt separator
(12) and an associated densimetric table separator allowing separating the
portion of heavy wastes (14) and the portion of light wastes (13).
Preferably the first composting bay and/or the second composting bay
comprise(s) humidity sources (6) allowing humidifying the concerned mixture of
wastes (4), the drying bay (2) comprising a recuperator (10) of a portion of the
moisture (17) contained in the mixture of pre-composted wastes (4) upon drying
of the latter, the recuperator (10) allowing supplying the humidity sources (6)
with moisture (17) retrieved upon drying said pre-composted wastes.
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Preferably the drying bay (2) comprises means for circulating drying air
(Adry) through the mixture of pre-composted wastes (4) in order to dry the latter,
the circulating means including at least:
- air blowing means (7) above the mixture of pre-composted wastes (4),
- air suction means (8) drying below the mixture of pre-composted
wastes (4).
Preferably it comprises means for treating the drying air (Adry) having
circulated through the mixture of pre-composted wastes (4) to substantially
discharge it from any composting, in particular odorous, emission.
BRIEF DESCRIPTION OF THE DRAWINGS
Other particularities and advantages of the invention will appear and will
come out in more detail upon reading the description made hereinafter, with
reference to the appended drawings, given only as an illustrative and non-
limiting example, in which:
- Figure 1 is a flow chart representing the different steps of the method
for treating a mixture of wastes according to the invention, as well as their
temporal sequence, including in particular steps A, B, C and D of said treatment
method.
- Figure 2 is a flow chart representing in more detail the course of step C
of Figure 1.
- Figure 3 illustrates, according to a side view, a longitudinal section of a
separation means including a ballistic belt separator, belonging to the plant for
treating a mixture of wastes according to the invention.
- Figure 4 represents, according to a perspective view, the separation
means of Figure 3.
- Figure 5 illustrates, according to a perspective view, a longitudinal
section of a drying/composting bay belonging to the treatment plant of Figures 3
and 4.
BEST WAY TO REALIZE THE INVENTION
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
The invention concerns a method for treating a mixture of wastes 4,
aiming to refine, valorize and/or recycle all or part of the latter, and in particular
for treating the biodegradable wastes contained therein.
Preferably, the mixture of wastes 4 is formed by domestic wastes, but it
may be also formed by wastes of economic or industrial activities, or by both,
said wastes not having undergone any prior sorting, or grinding.
Thus, this mixture of wastes 4 is advantageously formed by wastes
generated by households, by their consumption and by their daily life.
Preferably, the mixture of wastes 4 has not undergone any treatment and
forms a raw mixture of wastes 4. In particular, the raw mixture of wastes has not
undergone any grinding, nor does it have undergone any prior sorting aiming to
perform a segregation of one type of wastes from another, and in particular to
perform a separation of the biodegradable wastes and of the non-biodegradable
recyclable wastes. Preferably, the mixture of wastes 4 has been collected, for
example by means of garbage trucks, from households and/or economic
activities without said households and/or said economic activities having
performed any sorting or prior selection of the collected wastes. In particular,
the collection of the mixture of wastes 4 has not been selective. Thus, according
to a particularly interesting variant of the invention, the method of the invention
is a method for treating a raw mixture of non-ground wastes.
In this manner, the treatment method according to the invention is
characterized in that the mixture of wastes 4 has not undergone any treatment
and forms a raw mixture of wastes 4, which in particular has not undergone any
grinding, nor does it have undergone any prior sorting aiming to perform a
segregation of one type of wastes from another, and in particular to perform a
separation of the biodegradable wastes and of the non-biodegradable
recyclable wastes.
Of course, without departing from the scope of the invention, the mixture
of wastes 4 may have been deprived, on the contrary, from a portion of the
contained recyclable wastes, for example by the households during a
preliminary sorting, or it may have undergone a preliminary sorting, for example
by the households.
Advantageously, the wastes of the mixture of wastes 4 are collected in a
raw and undifferentiated way, mixed in bags, such as plastic trash bags closed
by the households, the method including a preliminary step of opening said
bags in order to release the contained wastes individually so as to form the
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
mixture of wastes 4 implemented in the method according to the invention,
which is a grouping of the wastes initially contained in said wastes. For
example, opening of the bags of wastes may be performed by means of a
device for opening bags, so as to enable the release of the wastes out of said
bags, preferably without damaging or altering said wastes.
In particular, because of the absence of any preliminary sorting before
the entry of the mixture of wastes 4 in the treatment method of the invention, the
wastes present heterogeneous sizes, shapes and consistencies, preferably with
various natures and origins. In particular, the considered mixture of wastes 4
may in particular comprise, at the same time, soft, hard, sharp, liquid, powdery,
solid, flat, hollow, full, sticky, slippery, fat, breakable, flexible, compressible,
incompressible, combustible, incombustible wastes, or still wastes cumulating
several of these characteristics. The mixture of wastes 4 contains a major
portion of used and undesirable elements, for example food wastes,
newspapers, papers, cardboards, glass, plastic, metal, textiles, various
combustibles and incombustibles, complex materials, households hazardous
wastes, inert wastes, bulky wastes.
According to the invention, the mixture of wastes 4 comprises
biodegradable wastes and non-biodegradable wastes, the biodegradable
wastes advantageously forming a non-negligible portion of the mixture of
wastes 4.
Advantageously, at least 10 %, preferably at least 20 %, of the mass of
the mixture of wastes 4 is formed by biodegradable wastes, and at least 10 %,
preferably at least 20 %, of the mass of the mixture is formed by non-
biodegradable recyclable wastes.
Preferably, a non-negligible portion of the mass of the mixture of wastes
4 is formed by biodegradable wastes, for example at least 50% of the mass of
the mixture of wastes, or still at least 60%, or still at least 80%. Preferably, a
non-negligible portion of the mass of the mixture of wastes 4 is in turn formed
by non-biodegradable recyclable wastes.
By « biodegradable waste », is meant, in the context of the invention, a
waste which, under the action of a natural environment, comprising for example
living organisms and/or air and/or water, can be decomposed, naturally and
spontaneously, into various elements likely to cause damages to the natural
environment (high demand for oxygen, emission of leachates) unless being
stabilized for example by composting. In particular, the living organisms may be
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
formed by micro-organisms such as bacteria, funguses or algae, which are
likely to degrade the biodegradable wastes through biochemical reactions.
Preferably, by « biodegradable wastes », are meant wastes which can be
degraded in this manner within a human lifetime, in a decade, or more
preferably in one year or in a few months, preferably in a few weeks. Preferably,
by « biodegradable wastes », are meant wastes which are likely to be used in
the production and the formation of a compost by composting the latter.
The « non-biodegradable » wastes, in the context of the invention,
constitute the other wastes, which do not undergo, spontaneously and naturally,
such a degradation, or which undergo such a degradation in a too slow way. In
particular, the « non-biodegradable » wastes are not adapted to enter into the
formation of a compost by composting the latter.
A « recyclable » waste, in the context of the invention, forms a waste
which may be easily transformed, for example chemically or mechanically, so
as to form a recycled matter similar to a raw material, which may be used for
example in the manufacture of an object. Preferably, the term « recyclable
waste » excludes the biodegradable wastes, even though in practice their
transformation into a compost confers a recyclable character to them. In the
context of the invention, the recyclable wastes may comprise for example:
non-metallic wastes, in particular polymers, glass, papers,
cardboard, newspapers, gravels, wood, textiles, electronics, etc.
metallic wastes, formed by any type of metals.
In the context of the invention, the term « non-recyclable wastes » refers
to any waste which does not fall in any of the categories described hereinabove
of « recyclable wastes » and « biodegradable wastes ». In particular, the non-
recyclable wastes regroup in particular wastes presenting a calorific value which
makes them likely to be transformed into refuse-derived fuels, and other
unusable ultimate wastes (complex wastes, etc.) intended for example to be
buried or incinerated.
Thus, the treatment method of the invention aims to valorize the mass of
mixed wastes forming the mixture of wastes 4 and in particular to particularly
convert the biodegradable wastes contained therein into a mixture 4 of refined
wastes 20, in such a manner that, preferably, the mixture 4 of refined wastes 20
forms a compost. Preferably, the mixture 4 of refined wastes 20 forms a
compost complying with the standard NF U 44-051. The standard NF U 44-051
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
of 2006, called « Organic amendments - Denominations, specifications and
marking », is a French standard.
According to an important feature of the invention, the treatment method
comprises the following successive steps:
Step A: the mixture of wastes 4 is subjected to a first composting
cycle so as to compost, at least partially, the biodegradable wastes of said
mixture of wastes 4, and to obtain a mixture of pre-composted wastes 4,
Step B: the mixture of pre-composted wastes 4 is subjected to a
drying so as to obtain a mixture of dried wastes 4,
Step C: the mixture of dried wastes 4 is separated into at least one
portion of heavy wastes 14 and one portion of light wastes 13, the portion of
heavy wastes 14 being formed by wastes with a volumetric mass heavier than
the wastes of the portion of light wastes 13,
Step D: the portion of light wastes 13 is subjected to a second
composting cycle so as to compost, at least partially, the contained
biodegradable wastes, and to obtain a mixture 4 of refined wastes 20.
The treatment method of the invention includes the treatment of the
mixture of wastes 4 by two successive composting cycles separated by a step
of drying the mixture of wastes 4 upon completion of the first composting cycle
in order to facilitate the separation and the easier refining of the mixture of
wastes 4. Thus, even if the mixture of wastes 4 is particularly heterogeneous
and presents numerous undesirable wastes which are not likely to be treated by
composting, it is possible to refine the latter through the method of the invention
so as to obtain refined wastes 20 the value of which is higher than the value of
the initial mixture of wastes.
Advantageously, the method is an industrial one wherein the steps are
performed in line and parallel to each other. For example, while a first mixture of
wastes 4 is subjected to step A, another mixture of wastes 4 is simultaneously
subjected to step B while it has already been previously subjected to step A.
By « composting », is meant, in the context of the invention, a biological
process of conversion and valorization of the organic wastes, and in particular
the biodegradable wastes contained in the mixture of wastes 4, by promoting
and/or accelerating the natural biodegradation process. Preferably, the
composting cycles of the method allow converting at least a portion of initial the
mixture of wastes 4 into a stabilized product, hygienic, rich in humic
compounds, preferably into a compost. By « composting », is meant a
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
composting, for example traditional or industrial, involving in particular the
action of micro-organisms in order to degrade and putrefy wastes of the mixture
of wastes 4, these micro-organisms being naturally present in the mixture of
wastes 4 and/or added to the mixture of wastes 4, and/or brought to multiply in
the mixture of wastes 4. In particular, the composting of the invention involves
an aeration of the mixture of wastes 4, and/or a regulation of the humidity of the
mixture of wastes 4 (for example by adding water to the mixture of wastes 4
and/or by reintroducing in the mixture of wastes 4 composting juices 11 emitted
by the latter), and/or an addition of micro-organisms to the mixture of wastes 4
and/or an addition of structurants 17 in order to stimulate the composting
process, and/or a supply of light, for example solar light.
Preferably, step A corresponds to, or comprises, a phase of degradation
of the wastes, in particular the biodegradable wastes, whereas step C
corresponds to, or comprises, a phase of maturation of the wastes, in particular
the biodegradable wastes, so as to obtain the mixture 4 of refined wastes 20,
the latter advantageously forming the compost. The degradation phase is
advantageously reflected by a proliferation of micro-organisms in the mixture of
wastes 4, whereas the maturation phase is preferably reflected by the
progressive decrease of the amount of micro-organisms having proliferated
during the degradation phase, and by the preservation of micro-organisms
beneficial to the soils. The degradation and maturation phases may overlap
each other, and even coincide with each other.
According to the invention, during step A, the first composting cycle
allows composting the biodegradable portion of the mixture of wastes 4,
whereas the non-biodegradable wastes remain, of course, substantially
unaltered, and serve in particular as structurants 17 to the composting process,
the structurant wastes 17 being intended in particular to improve the air flow
within the mixture of wastes 4 during composting, so as to improve the aerobic
composting.
Advantageously, both the first composting cycle of step A and the second
composting cycle of step D are performed in an aerobic manner. For this
purpose, the mixture of wastes 4 to be composted is preferably aerated, in
particular by making an air flow circulate throughout the mixture of wastes 4 to
be composted, or by stirring the mixture of wastes 4.
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Preferably, a light source 5 is brought to the mixture of wastes 4 in order
to improve its composting, for example a natural light source 5, and/or an
artificial light source 5.
Advantageously, during step A and/or step D and/or step B, the
considered mixture of wastes 4 being disposed in a heap which is turned over
several times, for example by means of an adapted loader 1, in order to
contribute to aerate the wastes (as illustrated for example in Figure 5).
Preferably, during step A, the mixture of wastes 4 is disposed in at least one
first composting bay 3, for example in a heap. Still preferably, during step D, the
wastes of the portion of light wastes 13 are disposed in at least one second
composting bay 3.
Preferably, during step A, and/or during step D, the considered mixture of
wastes 4 is humidified by means of humidity sources 6, the humidity sources 6
being formed for example by sprinkling devices or sprinkling ramps equipping
the first and/or second composting bays, the heaps being intended to be
sprinkled over by the sprinkling devices, said sprinkling devices being for
example disposed above said heaps.
Thus, a regulation of the humidity of the composting mixture is
advantageously operated during the composting cycles.
Advantageously, the method includes a step Y during which composting
juices 11 oozing from the mixture of wastes is recovered in order to supply the
humidity sources 6.
Preferably, step Y may also include capturing rainwater in order to supply
the humidity sources 6, which allows in particular reducing the possible
consumption of tap water, in particular drinking water, of the method.
Preferably, prior to step A, the method includes a step 1 during which a
second fraction of wastes, the size of which is larger than 110 mm, is separated
from the mixture of wastes 4. The wastes of larger size have been therefore
advantageously separated from the mixture of wastes 4 by means of a sorting
machine such as a rotary trommel. In particular, the wastes of the second
fraction of wastes have a lower density with respect to wastes remaining in the
mixture of wastes 4. Such segregation allows in particular increasing the
concentration of biodegradable wastes in the mixture of wastes 4, by separating
the most massive wastes from the initial mixture of wastes 4. By « size » of a
waste, is meant a geometric dimension characteristic of an individual waste,
which allows it, for example, to pass throughout a mesh with a corresponding
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
size if the size of the waste is smaller than the size of the mesh, or, on the
contrary, prevents it from passing if the size of said waste is larger than the size
of said mesh.
Preferably, before step A, and in particular after step 1, the mixture of
wastes 4 contains a major proportion of moist and/or sticky wastes, formed in
particular by biodegradable wastes, or at the very least adapted to be
composted. Advantageously, their sticky and/or moist character facilitates their
separation from the residual second fraction of wastes by the sorting machine.
Preferably, prior to step A, the method includes a step Z during which
metallic wastes 16 contained in the mixture of wastes 4 are separated, for
example by means of an electromagnetic separator and/or an eddy current
separator, so as to separate at least most of said metallic wastes 16 contained
in the mixture of wastes 4. Thus, the mixture of wastes 4 intended to the first
composting cycle is devoid of most of the metallic wastes 16 which it contained,
and in particular those the size and/or the mass of which is considerable, so
that the composting process of the first composting cycle is promoted and
accelerated. Advantageously, the metallic wastes 16 separated at step Z may
undergo the recycling step W.
According to the invention, step B, performed after step A for the
considered mixture of wastes 4, allows retrieving all or part of the moisture 6 of
the mixture of wastes 4 pre-composted during said step A. As illustrated in
Figure 5, to do so, the mixture of pre-composted wastes 4, disposed for
example in a heap in at least one, or still in several, drying bay(s), is subjected
to drying. Preferably, step B comprises a substep B1 of making a drying air flow
Asech circulate throughout said mixture of pre-composted wastes 4 in order to
dry the latter, the drying air flow Asech passing, to this end, throughout the heap
of wastes. Advantageously, the drying air Asech is formed by a dry air current
heated to a temperature comprised between 40°C and 90°C, preferably 70°C,
and which is capable of driving, during its passage in the mixture of pre-
composted wastes 4, the moisture 6 contained in the latter. Preferably, the
circulation of the drying air flow Asech is performed vertically, preferably from top
to the bottom, or still from bottom to the top. Thus, a suction of drying air 8 is
advantageously generated below the heap of pre-composted wastes.
Preferably, in order to implement step B, the mixture of pre-composted
wastes 4 is disposed in heaps in drying bays, for example at the ground level. In
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
order to contribute to drying of said mixture of pre-composted wastes 4, the
method includes turning the heap over once or several times.
Preferably, and in order to save natural resources, at least a portion of
the moisture 6 contained in the mixture of pre-composted wastes 4 is recovered
during step B, and the humidity sources 6 are supplied with the recovered
portion of moisture 6.
Preferably, the moisture 6 of the mixture of pre-composted wastes 4 is
therefore retrieved from the latter during step B and then reintroduced
afterwards in the portion of light wastes 13C at step D, so that this moisture is
not wasted, and is reused, at least partially.
In particular, all or part of the composting juices 11 emanating from the
mixture of pre-composted wastes 4 when drying is recovered, for example by
draining the latter by means of a draining means 9 of the drying bay 2.
Advantageously, these composting juices 11 are stored, and transported in
order to be reintroduced later on when implementing the first and second
composting cycles. In particular, since the composting juices 11 include water,
micro-organisms and other elements useful to the proper progress of a
composting operation, their reintroduction via the humidity sources 6 in a
mixture of wastes 4 to be composted allows improving the composting of the
latter while reducing the need for an external supply of water, micro-organisms
and other elements useful to the proper progress of the composting operation.
Advantageously, the drying air Asech is brought to circulate at least by an
air blowing 7 performed above the mixture of wastes 4, so that the drying air
Asech drains the moisture 6 of the mixture of pre-composted wastes 4, the step
of recovering the portion of moisture being performed, at least partially, by
condensation of the moisture 6 coming from the mixture of pre-composted
wastes 4 and drained by the flow of drying air Asech.
Preferably, in this instance, each drying bay 2 also comprises means for
circulating drying air Asech throughout the mixture of wastes 4 so as to dry the
latter, the circulation means including at least:
means for blowing air 7 above the mixture of pre-composted
wastes 4,
means for sucking drying air 8 below the mixture of pre-composted
wastes 4.
In addition, each drying bay 2 advantageously comprises a recuperator
of a portion of the moisture 6 contained in the mixture of pre-composted
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
wastes 4 when drying the latter, the moisture recuperator 10 allowing supplying
the humidity sources 6 with the moisture 6 recovered when drying said pre-
composted wastes.
Preferably, the flow of drying air Asech having circulated throughout the
mixture of pre-composted wastes 4 is treated in order to clear it substantially
from any composting emission, in particular any odorant emission, for example
by filtering, or by a biochemical treatment. To this end, the drying bay(s)
preferably comprise(s) means for treating the drying air Asech having circulated
throughout the mixture of pre-composted wastes 4 in order to clear it
substantially from any composting emission, in particular any odorant emission.
In a general manner, the possible emissions of air and pollutants resulting from
the implementation of the method are advantageously treated in this manner,
which allows the method to be substantially non-polluting and to generate no
odors.
Advantageously, upon completion of step B and prior to step C, said
method includes a step E during which a portion of wastes the size of which is
larger than about 30 mm, called the structurant wastes 17, whether they are
biodegradable or not, composted or not, is separated from the mixture of dried
wastes 4, and the concentration of structurant wastes 17 of other wastes
undergoing step A is adjusted by adding the portion of structurant wastes 17
separated from the mixture of dried wastes 4, in particular in order to structure
and scatter the first composting cycle. Advantageously, the separation of the
structurant wastes 17 is performed by means of a rotary trommel the mesh of
which allows segregating objects the size of which is larger than about 30 mm,
and objects the size of which is smaller than about 30 mm. Thus, the structurant
wastes 17 of the mixture of dried wastes 4 are advantageously reused in order
to improve a current or subsequent first composting cycle of another mixture of
wastes 4. In this manner, for the first composting cycle, it is not, or barely,
necessary to add structurants 17 coming from a source external to the
treatment method. Advantageously, a more or less large portion of the
structurant wastes 17 recovered in the mixture of wastes 4 undergoing step A is
reintroduced so as to adjust the concentration of structurants 17 of said mixture
of wastes 4, by addition of a supplement, to a predetermined value, preferably
allowing improving the first composting cycle. Preferably, the recovered
structurant wastes 17 which have not been reintroduced may be sorted, for
example manually or by means of a machine such as a rotary trommel, so as to
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
separate recyclable wastes, to be recycled, and non-recyclable wastes, which
undergo a refuse-derived fuel (RDF) production step X, or another type of re-
treatment such as burial or incineration. Indeed, at this stage of the method, it is
possible to consider making a portion of the mixture of dried wastes 4 enter in
the refuse-derived fuel production step X, to the extent that the wastes have
been dried and are dry enough, and in particular with an intrinsic humidity lower
than about 10 %.
According to the invention, all or part of the elements undesirable in the
formation of the final mixture of refined wastes 20 are separated during step C.
This separation is facilitated by the fact that, at this stage of the method, all or
part of the biodegradable wastes have undergone the first composting cycle, so
as to be composted, at least partially, and that these same biodegradable
wastes are dry, and are therefore non-sticky, disseminated in the form of a
powder or a gravel of a pre-compost which adheres, in a less significant
manner, to the non-biodegradable wastes. Furthermore, these pre-composted
and dry biodegradable wastes advantageously present, for most of them, a
volumetric mass which is low and distinct from the rest of the wastes of the
mixture of dried wastes 4. Thus, during step C, the portion of light wastes 13
comprises a major concentration of biodegradable wastes likely to be
transformed into a compost. Thus, it is easy to perform a selection of the wastes
likely to form the mixture 4 of refined wastes 20 among the mixture of wastes 4,
which was relatively heterogeneous at the beginning.
Preferably, step C and step E are carried out by means of means for
separating the mixture of dried wastes 4 at least into a portion of heavy wastes
14 and a portion of light wastes 13, the portion of heavy wastes 14 being
substantially formed by wastes with a volumetric mass heavier than the wastes
of the portion of light wastes 13. Advantageously, the separation means also
include the trommel associated to step E. Optionally, the trommel associated to
step E may be equipped with a brush allowing cleaning the portion of light
wastes 13 by friction, in order to separate the aforementioned wastes.
Preferably, the portion of light wastes 13 separated during step C
presents a volumetric mass lower than about 0.7 kg/L, preferably lower than
about 0.6 kg/L, the dry compost generally presenting a volumetric mass close to
0.5 kg/L. The plastic materials presenting a volumetric mass most often higher
than 0.8 kg/L may therefore be separated easily from the portion of light wastes
13. Thus, it is advantageously possible to separate, from the portion of light
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
wastes 13, the plastic materials, including the chlorinated plastic materials such
as polyvinyl chlorides (PVC), so that the mixture 4 of refined wastes 20 will be
substantially free of these materials upon completion of step D, or will contain
these materials in negligible proportions. For example, gravels and other
stones, metals, glass, paper fibers, whether degraded or under degradation,
may also be separated during step C, so that the mixture 4 of refined wastes 20
will be substantially free of these materials upon completion of step D, or will
contain these materials in negligible proportions.
As illustrated in Figure 2, step C preferably comprises a first substep C1
during which residual metallic wastes 16 are separated from the mixture of dried
wastes 4, for example by means of an electromagnetic separator and/or an
eddy current separator, so as to separate at least most of the residual metallic
wastes 16 contained in said mixture of dried wastes 4. Thus, are
advantageously separated again all the ferrous (by means of the magnetic
separator) and non-ferrous (by means of the eddy current separator) metallic
elements contained in the mixture of dried wastes 4, which would have not been
separated in particular during step Z. Advantageously, the « dried » state of the
wastes facilitates such a separation. Preferably, this first substep C1 contributes
to the formation of a high-quality mixture 4 of refined wastes 20, and in
particular a compost complying with the standard NF U 44-051. Thus, the
treatment method preferably comprises a step W of recycling the metallic
wastes 16 initially contained in the mixture of wastes 4. Preferably, the substep
C1 is performed before the separation of the heavy wastes and light wastes.
Preferably, besides the portion of heavy wastes 14 and light wastes 13,
step C comprises a second substep C2, during which, the mixture of dried
wastes 4 is separated, into a portion of intermediate wastes 19 the volumetric
mass of which is intermediate, that is to say comprised between the volumetric
mass of the wastes of the first and second portions of wastes, and said portion
of intermediate wastes 19 is added to the mixture of wastes 4 undergoing step
A. The intermediate wastes 19, the volumetric mass of which is for example
higher than about 0.6 kg/L but lower than about 0.7 kg/L, are preferably sent
back in a first composting cycle in accordance with step A. Indeed, it is possible
that the intermediate wastes 19 could be formed by biodegradable wastes the
degradation of which at the first composting cycle would be incomplete, or
which would have not dried completely. Thus, this second substep C2 allows
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
improving the separation between the wastes which will enter into the
composition of the mixture 4 of refined wastes 20, and the other wastes.
Preferably, the second substep C2 is performed after the substep C1,
and contributes to the separation of the heavy wastes and the light wastes.
Advantageously, step C, the first substep C1 and the second substep C2
are performed at least by means of the aforementioned separation means,
comprising in particular a ballistic belt separator 12 (as illustrated for example in
Figures 3 and 4) and an associated densimetric table separator. In this
instance, the method preferably implements a first ballistic belt 12A allowing
separating at first a portion of heavy wastes 14, the remainder of the mixture of
dried wastes 4 being directed towards a second ballistic belt 12B allowing
separating a portion of light wastes 13 and a portion of undetermined wastes
. Advantageously, the portion of undetermined wastes is directed towards the
densimetric separator, which allows separating the portion of undetermined
wastes in a finer way, in particular by separating light wastes joining the portion
of light wastes 13, heavy wastes joining the portion of heavy wastes 14, and the
portion of undetermined wastes 19 described hereinbefore.
As represented in Figures 3 and 4, the first and the second ballistic belts
12A, 12B are preferably included in the same machine, as illustrated in the
figures, the first ballistic belt 12A directly supplying the second ballistic belt 12B
by gravity. Advantageously, an accelerator belt may be placed upstream of the
first ballistic belt 12A so as to accelerate the mixture of dried wastes 4 in order
to project them on the first ballistic belt 12A with some kinetic energy so as to
improve the separation of the wastes. Preferably, the first ballistic belt 12A and
the second ballistic belt 12B present an inclination in the longitudinal direction,
which inclination can be adjusted, for example between 20° and 70° with
respect to the horizontal, in order to allow adjusting the separation of wastes. In
order to improve the separation, the first and/or the second ballistic belt 12A,
12B preferably includes an elastic rolling strip allowing making some types of
wastes rebound and roll on said rolling strip (in particular the heaviest ones),
some other wastes being intended, on the contrary, to adhere to the rolling strip.
Furthermore, the rolling strip may advantageously present adhesive or sticky
properties, in particular in order to make the finest wastes adhere thereto. In
particular, the mixture of dried wastes 4 comprises fines, which may
advantageously be recovered in order to be introduced in the portion of light
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
wastes 13, for example by scraping said ballistic belts 12 by means of a
tungsten-made scraper equipping said ballistic belts (not represented).
Upon completion of step C, in particular upon completion of substep C2,
and prior to step D, the method preferably includes a step F during which a
portion of coarse wastes 18 the size of which exceeds 12 mm, is separated
from the portion of light wastes 13, for example by means of a rotary trommel
the mesh of which allows segregating objects the size of which is larger than
about 12 mm, and objects the size of which is smaller than about 12 mm. In this
case, the coarse wastes 18 form light wastes the size of which is too
considerable to enter into the composition of the mixture 4 of refined wastes 20,
and in particular to form the compost complying with the standard NF U 44-051.
Advantageously, all or part of this portion of coarse wastes 18 is crushed in
order to be reintroduced in the portion of light wastes 13 during step D.
Alternatively, all or part of this portion of coarse wastes 18 is preferably
reintroduced in a mixture of wastes 4 undergoing step A. Furthermore, all or
part of this portion of coarse wastes 18, which may be formed by non-
compostable wastes, may enter in the refuse-derived fuel production step X, or,
if possible, undergo the recycling step W.
Finally, step D preferably allows refining the decomposition of the organic
wastes contained in the initial mixture of wastes 4. At this stage of the method,
the second composting cycle is performed on the portion of light wastes 13,
which come from the mixture of wastes 4 which has been devoided from most
of, still from all, the wastes undesirable in the formation of the final mixture 4 of
refined wastes 20. Thus, a high-quality mixture 4 of refined wastes 20, likely to
comply with particular standards, is obtained. Moreover, upon completion of the
treatment method, the major portion of, still all, the biodegradable wastes of the
mixture of wastes 4 enter into the composition of the final mixture 4 of refined
wastes 20.
Preferably, step D is performed by placing the portion of light wastes 13,
for example in heaps, in at least one second composting bay 3, for example
similar to the first composting bay 3.
Advantageously, step D comprises at least one substep D1 of re-
humidifying the light wastes, for example with the moisture 6 recovered during
the drying step B, in order to promote the natural composting, and in particular
the maturation of the compost during the second composting cycle so as to
from the mixture 4 of refined wastes 20. Preferably, step D also comprises an
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
aeration of the light wastes, for example in a similar way as step A (by means of
an air flow, or several turnovers of the heap of light wastes) in order to promote
the formation of refined wastes 20.
Preferably, step D may also comprise the reintroduction of micro-
organisms in said light wastes, coming for example from the first composting
cycle of step A.
Thus, it is possible to valorize the mixture of wastes 4 into a final mixture
4 of refined wastes 20, forming for example a compost in accordance with the
standard NF U 44-051.
The invention also concerns, as such, a plant for treating a mixture of
wastes 4, the latter being with heterogeneous sizes, shapes and consistencies,
the mixture of wastes 4 comprising biodegradable wastes and non-
biodegradable wastes, the plant comprising:
at least one first composting bay 3 allowing subjecting the mixture
of wastes 4 to a first composting cycle so as to compost, at least partially, the
biodegradable wastes of said mixture of wastes 4, and to obtain a mixture of pre-
composted wastes 4,
at least one bay 2 for drying the mixture of pre-composted wastes
4, allowing obtaining a mixture of dried wastes 4,
means for separating the mixture of dried wastes 4 at least into a
portion of heavy wastes 14 and a portion of light wastes 13, the portion of heavy
wastes 14 being substantially formed by wastes with a volumetric mass heavier
than the wastes of the portion of light wastes 13,
at least one second composting bay 3 allowing subjecting the
portion of light wastes 13 to a second composting cycle so as to compost, at
least partially, the contained biodegradable wastes, and to obtain a mixture 4 of
refined wastes 20.
Preferably, the composting plant forms a facility implementing the
method described hereinbefore. Henceforth, the elements of this composting
plant, 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 hereinbefore.
Preferably, the first bay, and/or the second bay, comprise humidity
sources 6 allowing humidifying the considered mixture of wastes 4, that is to
say the mixture of wastes 4 and the portion of light wastes 13, respectively.
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Advantageously, the drying bay 2 comprises a recuperator 10 of a
portion of the moisture 6 contained in the mixture of pre-composted wastes 4
when drying the latter, the recuperator 10 allowing supplying the humidity
sources 6 with the moisture 6 recovered when drying said pre-composted
wastes.
Advantageously, the recuperator 10 corresponds to the recuperator
described hereinbefore, and comprises for example a device for condensing the
moisture 6 contained in the drying air, which has been extracted from the
mixture of pre-composted wastes 4. For example, the recuperator 10 also
comprises a device for draining the composting juices 11, disposed at the
ground level 12, allowing capturing and draining said composting juices 11.
Preferably, the drying bay 2 comprises means for making a drying air
Asech circulate throughout the mixture of pre-composted wastes 4 so as to dry
the latter, the circulation means including at least:
means for blowing air 7 above the mixture of pre-composted
wastes 4,
means for sucking drying air 8 below the mixture of pre-composted
wastes 4, disposed for example at the ground level 12D, under the heap of pre-
composted wastes.
Advantageously, such an arrangement allows creating a flow of drying air
Asech from top to the bottom so as to allow drying the mixture of pre-composted
wastes 4.
Preferably, the condensation device is placed within the suction means 7
and/or the blowing means 8.
Preferably, the drying bay 2 comprises a light source 5 as described
hereinbefore, allowing irradiating the mixture of wastes 4 as it dries, and
therefore facilitating its drying.
Advantageously, the composting bay 3 also comprises a light source 5
allowing irradiating the mixture of wastes 4 as it is composted, and therefore
improve the composting of the latter (as illustrated in Figure 5), the natural light,
and in particular the solar rays, being favorable to the development of life, and
in particular to the micro-organisms which are sensitive thereto.
Advantageously, the light source 5 may be formed by a glazing placed at
the base of the composting 3 or drying 2 bay, letting the Sun light pass through
and protecting the bay from bad weather.
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Advantageously, such an arrangement allows avoiding plugging of the
circulation means.
Advantageously, the plant further comprises means for treating the
drying air Asech having circulated throughout the mixture of pre-composted
wastes 4 in order to clear it substantially from any composting emission, in
particular any odorant emission, for example as described hereinbefore.
Preferably, the composting bays and the drying bays are identical, and/or
coincident, so as to form composting/drying bays and ensure both associated
functions selectively. Of course, the drying bays and the composting bays may
be perfectly distinct from each other without departing from the scope of the
invention.
As described hereinbefore, the separation means preferably include at
least one ballistic belt separator 12 and an associated densimetric table
separator allowing separating the portion of heavy wastes 14 and the portion of
light wastes 13.
Thanks to such a plant, all or part of the method described hereinbefore
may preferably be performed in an automated and industrial manner.
POSSIBILITY OF INDUSTRIAL APPLICATION
The invention finds its industrial application in the design, the realization
and the implementation of means for treating a mixture of wastes with
heterogeneous sizes, shapes and consistencies, which mixture comprises
biodegradable wastes and non-biodegradable recyclable wastes.
403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Claims (22)
1. A method for treating a mixture of wastes, the latter being with heterogeneous sizes, shapes and consistencies, the mixture of wastes comprising biodegradable wastes and non-biodegradable wastes, the method wherein it includes the following successive steps: Step A: the mixture of wastes is subjected to a first composting 10 cycle so as to compost, the biodegradable wastes of said mixture of wastes, and to obtain a mixture of pre-composted wastes , Step B: upon completion of the first composting cycle, the mixture of pre-composted wastes is subjected to a drying so as to obtain a mixture of dried wastes , 15 Step C: the mixture of dried wastes is separated into one portion of heavy wastes and one portion of light wastes , the portion of heavy wastes being formed by wastes with a volumetric mass heavier than the wastes of the portion of light wastes, the portion of light wastes having a density less than about 0.7 kg/L, 20 Step D: the portion of light wastes is subjected to a second composting cycle so as to compost, the contained biodegradable wastes, and to obtain a mixture (4) of refined wastes.
2. The treatment method according to the preceding claim, wherein, prior 25 to step A, the method includes a step 1 during which a second fraction of wastes the size of which is larger than 110 mm is separated from the mixture of wastes.
3. The treatment method according to any one of the preceding claims, 30 wherein, prior to step A, it includes a step Z during which metal wastes contained in the mixture of wastes are separated, for example by means of an electromagnetic separator and/or an eddy current separator, so as to separate at least most of said metal wastes contained in the mixture of wastes. 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
4. The treatment method according to any one of the proceeding claims, wherein, during step A, and/or during step D, the concerned mixture of wastes is moistened by means of moisture sources.
5 5. The treatment method according to the preceding claim, wherein it includes a step Y during which composting juices oozing from the mixture of wastes are retrieved for supplying the humidity sources.
6. The treatment method according to any one of claims 4 or 5, wherein a 10 portion of the moisture contained in the mixture of pre-composted wastes during step B is retrieved, and in that the humidity sources are supplied with the portion of the moisture retrieved accordingly.
7. The treatment method according to any one of the preceding claims, 15 wherein step B comprises a substep B1 of circulating a drying air flow (Adry) through said mixture of pre-composted wastes in order to dry the latter.
8. The treatment method according to the preceding claim, wherein the circulation of the drying air flow (Adry) is performed substantially vertically, 20 preferably from top to the bottom.
9. The treatment method according to any one of claims 7 or 8, wherein the drying air (Adry) is circulated at least by means of an air blowing performed above the mixture of wastes, so that the drying air (Adry) drains moisture from 25 the mixture of pre-composted wastes, the step of retrieving the portion of moisture being carried out at least partly by condensation of moisture coming from the mixture of pre-composted wastes and drained by the drying air flow (Adry). 30
10. The treatment method according to any one of claims 7 to 9, wherein the drying air flow (Adry) having circulated through the mixture of pre-composted wastes is treated to substantially discharge it from any composting, in particular odorous, emission. 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
11. The treatment method according to any one of the preceding claims, wherein, during step A and/or step D and/or step B, the concerned mixture of wastes is disposed in a heap which is turned over several times. 5
12. The treatment method according to any one of the preceding claims, wherein, at the end of step B and prior to step C, said method includes a step E during which, is separated from the mixture of dried wastes, a portion of wastes the size of which is larger than about 30 mm, called structurant wastes, and the concentration of structurant wastes of a second mixture of wastes subjected to 10 step A is adjusted by adding therein the portion of structurant wastes thus separated from the mixture of dried wastes, so as in particular to structure and seed the first composting cycle.
13. The treatment method according to any one of the preceding claims, 15 wherein step C comprises a first substep C1 during which is separated from the mixture of dried wastes, residual metal wastes contained therein, for example by means of an electromagnetic separator and/or an eddy current separator, so as to separate at least most of the residual metal wastes contained in said mixture of dried wastes.
14. The treatment method according to any one of claim 3 or 13, wherein it comprises a step (W) of recycling metal wastes initially contained in the mixture of wastes. 25
15. The treatment method according to any one of the preceding claims, wherein step C comprises a second substep C2 during which, besides the portion of heavy wastes and light wastes, the mixture of dried wastes is separated from a portion of intermediate wastes the density of which is intermediate, that is to say comprised between the density of the wastes of the 30 first and second portions of wastes, and during which said portion of intermediate wastes is added in the mixture of wastes subjected to step A.
16. The treatment method according to any one of the preceding claims, wherein the portion of light wastes separated during step C has a density less 35 than about 0.6 kg/L. 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
17. The treatment method according to any one of the preceding claims, wherein, upon completion of step C and prior to step D, said method includes a step F during which is separated from the portion of light wastes, a portion of coarse wastes the size of which exceeds 12 mm.
18. The treatment method according to any one of the preceding claims, wherein the mixture of wastes has not been subjected to any treatment and forms a raw mixture of wastes, on which in particular neither grinding has been carried out, nor prior sorting aiming to perform a segregation of one type of 10 waste relative from another, and in particular to perform a separation of biodegradable wastes and non-biodegradable recyclable wastes.
19. A plant for treating a mixture of wastes, the latter being with heterogeneous sizes, shapes and consistencies, the mixture of wastes 15 comprising biodegradable wastes and non-biodegradable wastes, the plant wherein it comprises: at least one first composting bay allowing subjecting the mixture of wastes to a first composting cycle so as to compost, at least partially, the biodegradable wastes of said mixture of wastes, and to obtain a mixture of pre- 20 composted wastes, at least one bay for drying the mixture of pre-composted wastes, allowing obtaining a mixture of dried wastes, said bay for drying being designed for drying said mixture of pre-composted wastes upon completion of the first composting cycle, allowing obtaining a mixture of dried wastes, 25 means for separating the mixture of dried wastes at least into a portion of heavy wastes and a portion of light wastes, the portion of heavy wastes being substantially formed by wastes with a volumetric mass heavier than the wastes of the portion of light wastes, the portion of light wastes having a density less than about 0.7 kg/L, 30 at least one second composting bay allowing subjecting the portion of light wastes to a second composting cycle so as to compost, at least partially, the contained biodegradable wastes, and to obtain a mixture of refined wastes, wherein the separation means include a ballistic belt separator 35 and an associated densimetric table separator allowing separating the portion of heavy wastes and the portion of light wastes. 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
20. The treatment plant according to the preceding claim, wherein the first composting bay and/or the second composting bay comprise(s) humidity sources allowing humidifying the concerned mixture of wastes, the drying bay 5 comprising a recuperator of a portion of the moisture contained in the mixture of pre-composted wastes upon drying of the latter, the recuperator allowing supplying the humidity sources with moisture retrieved upon drying said pre- composted wastes. 10
21. The treatment plant according to any one of claim 19 or 20, wherein the drying bay comprises means for circulating drying air (Adry) through the mixture of pre-composted wastes in order to dry the latter, the circulating means including at least: - air blowing means above the mixture of pre-composted wastes, 15 - air suction means drying below the mixture of pre-composted wastes.
22. The treatment plant according to claim 21, wherein it comprises means for treating the drying air (Adry) having circulated through the mixture of pre-composted wastes to substantially discharge it from any composting, in 20 particular odorous, emission. 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC 403283NZ CLEAN SPEC AND DWGS 8 March 2021.DOC
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1454696 | 2014-05-23 | ||
FR1454696A FR3021237B1 (en) | 2014-05-23 | 2014-05-23 | METHOD AND INSTALLATION FOR TREATING A MIXTURE OF WASTE WITH TWO COMPOSTING CYCLES |
PCT/FR2015/051371 WO2015177486A1 (en) | 2014-05-23 | 2015-05-22 | Method and installation for treating a mixture of waste, having two composting cycles |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ727153A NZ727153A (en) | 2021-03-26 |
NZ727153B2 true NZ727153B2 (en) | 2021-06-29 |
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