FR2733170A1 - Composting of organic waste using cultures of worms - Google Patents

Abstract

A process and installation are claimed for the compositing of organic waste with the assistance of earthworms. Waste is first subject to a 30-60 day period of hygienisation, where it is spread in a horizontal layer 0.5-1.5 m deep and turned 2-5 times during this period. The waste is then spread (5 1) to a depth of 0.1-0.25 m in a rectangular bed (3), over a layer of substrate (4) containing an inoculum of worms. Every 20 days or so more waste is added to the bed (5 2) until a final depth of about 1 m is reached. During this time the material is kept damp by sprays, and the area ventilated. Excess liquid is collected from the base of the bed. Eventually the worms are collected in a selected area and the compost removed from the bed.

Description

Bioprocessing process and installation for recovery
organic waste through vermiculture and biotechnology.

 The present invention relates to a biotreatment process and installations for the recovery of organic waste by industrial vermiculture and biotechnology.

 The technical sector of the invention is the field of transformation of waste into a useful or at least non-harmful material, using in particular the known capacities offered by vermiculture.

 One of the main applications of the invention is to recover the waste thus transformed into fertilizers called vermicompost, which can then be packaged to be sold to users wishing to enrich their soil.

 Such treatment for this recovery application has indeed been known for a very long time, has been for a long time and is still used by farmers, in a closed production circuit, for essentially their personal needs, namely to dispose of their waste by storing it without control their development in a corner of their property for long periods, then recover them, after ingestion and natural digestion by earthworms existing in the soil, to fertilize their land.

 However, this artisanal, natural method, which is in fact uncontrolled, is not intended and is not suitable for treating waste and eliminating it on a large scale and in a safe and repetitive manner; however, these are becoming a general concern: our industrial and agronomic potential has increased at the cost of a mountain of waste. This waste accompanied economic and industrial growth as long as the cost of energy was low and environmental protection was not taken into account: it was considered that it was better to consume the material than to recycle it. But, when primary energy becomes expensive, and / or it has to be imported, and the safeguard, both visually and for the pollution thus created, of our environment, is no longer compatible with constant increase in our waste, we must limit production, and recover from this waste, part of the energy invested and no longer store it in landfill or in the wild, no matter how.

 In addition, the ever-increasing cost of this type of disposal, as well as the overcrowding of landfill sites, makes it necessary to choose one or rather several alternative solutions adapted to each following case. the type, source and location of the waste.

 In the near future, industrialized countries will thus be forced to take measures aimed at recovering energy and protecting the environment; landfills as we know them and where residues of all kinds accumulate, are bound to disappear in favor of treatment centers.

 At present, it can be considered that 50% of organic waste is still deposited without precautions or transformations in landfills and that only the remaining 50% is treated but with more or less constraints and / or residual drawbacks.

There are actually four categories of "treatment"
- the first is incineration, which is the only method really industrialized to date on a large scale, and which treats 35% of waste, but which does not allow a true recovery, even if we can recover the calories usable in urban or collective heating in addition, this process generates, on the one hand, atmospheric pollution by rejection of toxic gases, and on the other hand combustion by-products which must in any case be stored and which, in the time, are also dangerous.

- the second is the anaerobic fermentation in the liquid phase of organic matter, in particular household waste, of which there are only a few units in operation: these allow, on the one hand to produce combustible gas rich in methane, and on the other hand, to recover a ground product which, once wrung out, provides combustible material and digestate which can be used as fertilizer. In this processing category, FR patent applications can be cited. 2,577,940 published on August 29, 1986 and FR. 2,551,457 published on 08/03/1985 jointly deposited by the Companies UIE and VALORGA and Gentlemen
DUCELLIER and PAVIA, and relating to processes and installations for achieving degradation in an anaerobic environment of products, by-products and organic waste. However, this type of process requires a significant installation (digester or fermenter of at least 3,000 m3) fairly complex, which must resist corrosion, and with an energy supply and additives as well as gas recovery and storage equipment; moreover, we cannot treat all types of waste there; this type of treatment is also difficult to develop.

- the third category is accelerated mineralization by chemical reaction using quicklime to essentially destroy organic matter, and various processing supplements, such as by heating, adding other reagents, grinding, compacting, in order to theoretically obtain a residue Several types of processes have been studied in this category of treatment, some of which have been the subject of patent applications, such as those FR. 2,472,421 published on 03.07.1981 and deposited by Mr. GERONIMO, that FR. 2.583.742 of 26.12.1986 by LOMA FINANCE and that EP. 427.899 of 22.05.1981 by the Swiss company GOMACRIS, these three requests citing for inventor Monsieur
BIEZ, that FR. 2.612.427 of 23.09.1988 by the Swiss company CATREL and that EP. 602293 of 07.12.92 from Monsieur DE BLANGY
however, most, with the possible exception of the last of these patent applications, have not been the subject of any real significant industrial achievement, since the first have come from the results of empirical experiments without explanation of the chemical-physical stages and thus giving products with non-repetitive characteristics and which cannot be obtained on a large scale. In addition, even if one of these processes, of which prototypes have proved their worth, makes it possible to achieve the advertised objectives, it nevertheless consumes l energy requires inputs of chemicals and investment in fairly complex machines, which can then only be installed for large communities.

 - the fourth category is the natural fermentation in the open air of organic waste, which treats 10% of the total mass of waste, and which makes it possible to obtain, by mixing it with mineral matter, fertilizers called compost, which can be considered that vermicompost obtained by vermiculture as defined above, are part: this type of treatment requires large spaces, however, a long wait to allow the piles of stacked waste to rot, ferment and thus transform at least partially into compost , which in any case pollutes the environment, at least by its odor, does not allow repetitivity and reliability in the characteristics of the final product obtained and requires sorting upstream and downstream: it is therefore not a matter of '' a real industrial process and is not really adapted to the problem posed, in particular for organic waste not of agricultural origin, which is in weak t the only area in which this treatment is mainly used, since it meets the needs of farmers well Indeed, each harvest exports from the soil the elements that must be reintroduced before each crop. Chemical fertilization, known as conventional, poses delicate adjustment problems; the yield of an application is often poor because of losses due to leaching: organic fertilization bringing the elements in a more slowly soluble form is then an answer. The composts are prepared to make this organic fertilizer as effective as possible.

 The present invention falls into this latter category of treatment but on the one hand in a more elaborate form called vermiculture or vermicomposting, and on the other hand in combination with complementary methods and means improving its efficiency, its reliability, performance ...; vermiculture uses a very widespread association in the original environment, between soil worms and decomposing organic matter: it is a different treatment mode from simple fermentation or bacteriological composting.

Worldwide (United States, Japan, Europe, Indonesia,
Africa), a great deal of laboratory work and numerous industrial farms have highlighted the essential properties of the environment in which populations of earthworms develop (acidity, mineral composition, type of fermentation to be avoided, temperature , etc ...) as well as the parameters of population growth. This knowledge is thus likely to improve the management of a breeding in a given medium, but had not yet made it possible to determine all the necessary phases of treatment and their control, nor on what type of waste and how consequently, to raise earthworms on an industrial scale and what would be the potential use of these worms and the vermicompost obtained by this method.

 There is certainly known a process using vermicomposting in an industrial context as described in FR patent applications. 2,653,687 and FR. 2,653,686 from the SOVADEC Waste Recovery Company and deposited on October 27, 1989 but requiring fairly complex and expensive processing and handling equipment, their implementation is in fact the only one really described, with no details on the process of the process and the control of the treatment phases themselves by vermiculture, which does not make it possible to optimize these and to obtain a real efficiency of the process and a product which is truly reusable respecting the existing standards, such as those applicable to organic amendments defined in France by standard NFU 44051.

 The problem posed, and which is the object of the present invention, is thus to perfect this natural sector which is worm farming and to control the process of manufacturing a final product which can be a fertilizer, by recovering organic waste. of all origins, such as those from agriculture, the food industry, urban communities, household waste, etc., while minimizing the necessary floor space, the total treatment time to less than approximately two years, without requiring any specific equipment, neither for storage, nor for handling, with therefore the lowest possible investment, which can be installed near the place of production of the waste to be treated, without however creating discomfort in the environment, respecting existing standards, both in the field of waste treatment and in that of the application of the final valued product, with good reliability ity and repeatability in the characteristics of this final product obtained.

The solution is a method of treating organic waste by vermiculture, such as depositing said waste on an almost horizontal surface with an initial thickness of 0.50 meters to 1.50 meters, an exemplary embodiment of which is shown in FIG. 1, and
- Different types of organic waste are combined in order to obtain the best possible yield from the first phase defined below of putrefaction, or called precomposting or even mineralization of organic matter, or said according to the present invention of bihygienization: by example, for waste such as sewage sludge or grease or residues from the food industry which are then too homogeneous to allow, during the next phase, earthworms to be able to move around easily, we associate and we mix vegetable waste there such as for example straw: this one, on the one hand, blocks oxygen, and brings carbon and on the other hand, allows earthworms to move there more easily and find the elements necessary for faster processing.

The objective of this first mixing step is the preparation of the organic waste substrate if those directly produced do not allow to have a structure and a certain composition of the elements which they contain, so that these are complementary, and that their natural transformation takes place in the best conditions
- The waste substrate 1, thus prepared or initially produced, is left in place during a so-called bihygienization period of thirty to sixty days, during which it is homogenized by two to five inversion operations; during this bihygienization phase, it is also possible to spread non-pathogenic microorganisms such as those contained in various existing products and commercially available to date treat household waste as soon as it is collected, such as that called "ANDAIN" from the Company
APPLIED TECHNIQUES AND BIOCHEMISTRY (TBA), which is a complex of mutated bacteria in directed action and freeze-dried microorganisms, or for eliminating fats and starches in agrifood such as the product called "SYMBIO" from the company BIOLOGIE
INDUSTRIAL AND MICRO-ORGANISMS, which is a powder comprising selected and freeze-dried bacteria on bean sprouts, reactivation masses, nutrients and trace elements, or to degrade composts such as the product called "ODABIO
GEO "from the company CODABIO, which is a hygroscopic powder comprising selected microorganisms and fixed on mineral supports, nutrients and trace elements: the spreading of such non-pathogenic microorganisms among those cited above as an example, accelerates the reaction to reduce the volume of substrate and at the same time reduces odors, which are all the stronger as this phase is very thermophilic; it is also possible to recover, develop and use bacteria already existing in the medium and that we can qualify as sedentary bacteria; they are all the more adapted to the environment that they come from: we can then wake them up, stimulate them to increase their activity and reinject them into the environment; the duration of this phase from thirty to sixty days depends on the structure and the initial composition of the substrate in place and this operation can be carried out under a greenhouse type shelter ventilated ricole, in order to contain odors and to be able to eliminate them, for example by spraying biological products containing suitable microorganisms, such as those called "SYMBIODOR" from the company UNISYMBIOSE and which are liquids composed of metal salts, surfactants and concentrated fragrance agents
- at least one litter 3 is placed at the bottom, placed close to the previous surface and an exemplary embodiment of which is shown in FIG. 2, having enabled the first bihygienization treatment, a substrate 4 containing a worm farm and covers it with a layer 51 of 0.10 to 0.25 meters of organic waste substrate from the previous precomposting phase
- We add at the earliest every twenty days, or approximately every month, another layer 52 of the same thickness of said bihygienized substrate which thus completely covers the previous layer and so on the maximum thickness of 0.25 meters of each layer regular keeps it in aerobic phase, which ensures earthworms better treatment efficiency and allows them to easily go up between successive layers 5 as they are added; by waiting a month between each layer, we obtain a reduction of about 70% in the volume of each: thus, by stacking for example twenty successive layers of 0.15 meters of precomposted substrate, we obtain after about twenty months a final thickness of the order of 0.80 meters. We can note that this result is obtained with at least one cycle of digestion of the waste contained in each layer by earthworms but that these can recycle up to six times their own waste, because they return there if necessary, in particular if we are slow to add a successive additional layer on top of the previous ones. This may be desired depending on the type of initial waste that has been collected and the desired result, if, for example, on the contrary, we want to maintain a certain biological and organic activity in the product, make it completely inert by reducing at the same time Its volume is maximized. During this earthworm treatment phase, the litter box which contains it is regularly humidified while maintaining a humidity between 60 and 70% humidity because above it, the earthworms risk drowning and below, they die because they no longer eat. This vermiculture or vermicomposting phase is preferably carried out under a ventilated shelter of the agricultural chapel greenhouse type, the roof of which stops at least the ultraviolet rays, since these are not compatible with good earthworm activity; moreover, the existence of such a shelter makes it possible to recover in a protected environment the vapor-transpirations of the organic mass and this recovery completes the necessary hygrometry in addition to the misting indicated above.
- We continue during this vermicomposting phase to add successive layers of precomposted substrate in said litter until reaching a thickness after treatment with earthworms of a maximum of one meter; we then remove the earthworm breeding by recovering it in a selective swath such as for example manure, which we deposit for eight to fifteen days on top of the litter at the end of the vermicomposting cycle without waiting too long beyond from twenty to thirty days after the deposit of the last layer if you want to recover a slightly active product as indicated above; we can however let the earthworms continue to act since they can recycle their own waste at least six times according to the use of the final product that we want
- after recovery of the earthworms adults in the selective swath, we sow the product 8 in the litter 3 for about a month: there remain indeed the young earthworms which did not have the strength or the time to move in the swath and which continue to participate in the maturation of the product but which are not numerous enough to reproduce there, all the more so since they no longer have moisture, nor any added substrate "new"
- the vermicompost is then removed from the litter, either to return it to the wild in the state thus obtained, or to recover it in subsequent stages such as
- it is put to dry and ripen under a protected and ventilated shelter in air flow for about three months, which shelter must protect the product, at least from ultraviolet rays and also from rain, which would otherwise risk washing it out by removing in particular the trace elements this step is decisive for the agronomic quality of the product if we want to obtain fertilizer, because it is then a natural bio-physico-chemical transformation of the components, digested by the earthworms and which thus reach maturation by mutual stability
- then, the product is sifted once mature and dried, from which we remove the waste not treated by earthworms, such as glasses, plastics, metals, bones, which are too hard to be attacked and digested by earthworms and that it is sent to the landfill since it is then inert waste.

 The product thus obtained, called vermicompost, can then be put in sachets and sold to any user wanting to enrich their soil, as with any type of fertilizer, except that it is of course natural and does not include chemicals those which can originally exist in the waste have been treated and modified by the digestion of earthworms; similarly if heavy metals initially existed in these wastes, these were also blocked and inactivated during this digestive phase of earthworms, which constitutes vermicomposting.

 The result is a new process and new installations making it possible to carry out said process for treating organic waste by vermiculture according to a controlled natural method, without discharge into the natural environment and using standard known material, easy to implement, at a cost. very reduced, and meeting all of the objectives mentioned above in the problem posed.

 The combination of vermiculture with biotechnologies, as well as the mastery, optimization and control of each of the operating phases indicated above, make it possible to obtain reliability and repeatability in the characteristics of the final product, optimal efficiency with good profitability and application on an industrial scale for all types of organic waste.

 We could cite other advantages of the present invention, but those mentioned above already show enough to prove its novelty and interest. The description and the attached diagrams represent an exemplary embodiment of an installation according to the invention but are in no way limiting: other embodiments are possible within the scope and scope of this invention, in particular by changing the layout and shape of the litter boxes, as well as the type of shelter protecting them.

 Figure 1 is a perspective diagram of a type of litter for the so-called bihygienization pre-composting phase.

 Figure 2 is a schematic perspective view of a type of litter for the earthworm phase itself.

 Figure 3 is a schematic perspective view of a shelter allowing the last phase of maturation of the product with a view to its recovery.

 A treatment installation, which is therefore biotreatment, of organic waste 1 by vermiculture and biotechnology according to the phases of the process described above comprises almost horizontal surfaces 2 for receiving the initial waste 1: according to FIG. 1, at least one first type of litter 6 from 0.50 meter to 1.50 meters high and rectangular in shape, which is built on said surface 2; it is preferably sealed and equipped with recovery means to allow, by draining the percolates, to recover these and then to be able to biologically treat them with bacteria which eliminate the pathogenic elements and which can then be recycled in the method of the invention.

 Said first litter 6 is preferably combined with at least one other and more if necessary: they are then arranged parallel to each other along their long length and separated by spaces 10 for circulation and access for loaders and are of preferably open, at least on a small side at one of their ends 9, so that said loader tractors can enter there to deposit, recover and / or return the deposited substrate 1 by moving it for example from a litter 6 to another .

 These first litters 6 can be protected under a shelter of ventilated agricultural greenhouse type which can be common to those of the following litters 3 or possibly under a different shelter.

 The installation according to the invention in fact comprises at least one second type of litter 3, also of rectangular shape, the bottom of which is sandy: in fact, on the one hand, earthworms do not like concrete and, on the other hand, the sand allows them a certain thermal regulation and in case of a problem such as a disturbance in the waste brought or in the humidity, earthworms can take refuge there; the sand also allows filtration of residual percolates from this vermicomposting phase; this type of litter 3 is from a height of 0.50 centimeters to 1 meter and equipped with misting sprinklers with a control of the rate of hygrometry to keep it in the range 60 to 70% humidity, for example with a check at least four times a day.This second litter 3 must be protected in a ventilated shelter protecting the vermicompost 5 at least from ultraviolet rays and rain, as for example by a greenhouse of agricultural chapel type coated with 'a film material having the desired characteristics.

 Said second litter is preferably combined with at least one other and more if necessary; they are then arranged parallel to each other along their great length and separated by spaces 10 for circulation and access to loader or tipper tractors or spreaders which access them laterally along at least one of their long sides which is closed by any means consisting of removable elements which can be superimposed, such as for example boards, to follow the successive levels of the added layers.

 Depending on the number of these, this phase can therefore last from 18 to 24 months, after which we recover and remove the vermicompost 8 obtained, after weaning on the order of one month, to put it to dry and at maturity in a shelter 7 protected from ultraviolet rays and rain and ventilated in drafts and for at least 90 days.

Claims (10)

 1. Process for treating organic waste (1) by earthworms, such as depositing said waste on an almost horizontal surface (2), with an initial thickness of 0.50 meters to 1.50 meters, characterized in that  - the waste substrate (1) is left in place during a bihygienization period of thirty to sixty days, during which it is homogenized by two to five inversion operations  - deposit at the bottom of at least one litter (3), a substrate (4) containing a worm farm, and cover it with a layer of 0.10 to 0.25 meters (51) of substrate organic waste (1) from the previous phase of bio-sanitation  - we add, as soon as every 20 days, another layer (52) of the same thickness, of said substrate, which thus completely covers the previous layer, we regularly moisten said litter (3) and we thus continue to add layers ( 52) successive precomposted substrate until reaching a thickness after vermicomposting treatment of a maximum of one meter  - the earthworm breeding is removed by recovering it in a selective swath which is deposited on the litter at the end of the previous vermicomposting cycle and the product (8) thus obtained is weaned  - the vermicompost is removed from the litter (3).  2. Treatment method according to claim 1, characterized in that, during the bihygienization phase, a spreading of non-pathogenic bacteria is carried out which accelerate the reduction in the volume of the substrate (1) and reduce odors.  3. Treatment method according to any one of claims 1 or 2, characterized in that at least the worm composting treatment is carried out in a ventilated shelter whose roof stops at least the ultraviolet rays.  4. Treatment method according to any one of claims 1 to 3, characterized in that the organic waste (1) is deposited for their bihygienization phase, in litter boxes (6) built on said surface (2) which is waterproof and equipped with means for the recovery of percolates that are treated biologically with bacteria which eliminate pathogenic elements.  5. Treatment method according to any one of claims 1 to 4, characterized in that the humidity of said litters (3) containing the vermicompost is maintained, at a rate of between 60 and 70% humidity, by misting water spray.  6. Treatment method according to any one of claims 1 to 5, characterized in that there is a sandy soil at the bottom of the vermicomposting litter (3) and on which the substrate (4) containing l is deposited. worm farm.  7. Treatment method according to any one of claims 1 to 6, characterized in that after removal of the vermicompost (8) from the litter (3):  - it is put to dry and ripen under a shelter (7) protected and ventilated in air flow for about three months  - Then the product is sifted once mature and dried, from which the waste not treated by earthworms is thus removed during the vermicomposting phase.  8. Installation for the treatment of organic waste (1) by earthworms, comprising almost horizontal surfaces (2) capable of receiving said waste, characterized in that it comprises at least a first litter (6) of 0.50 meters to 1 , 50 meters high and rectangular in shape, built on said waterproof surface (2), equipped with percolate flow recovery means, and receiving the substrate of initial organic waste (1), at least one second litter (3), also of rectangular shape, the bottom of which is sandy, from a height of 0.50 to 1 meter, and equipped with mist sprayers, and at least one ventilated shelter protecting at least said second litter (3).  9. Treatment installation according to claim 8, characterized in that said shelter from the at least said litter (3), is a chapel greenhouse of agricultural type coated with an anti-ultraviolet film material.  10. Treatment installation according to any one of claims 8 or 9, characterized in that said first and second litters (6, 5) are at least two in number of each type, which are arranged parallel to each other, according to their very long, and separated by spaces (10) for circulation and access for loading tractors, said first litters (6) being open at least on a small side at one of their ends (9) and said second litters (5) being accessible laterally along at least one of their long sides, which is closed by any means consisting of removable and superimposable elements by successive level.