WO1993014047A1 - Integrated biomethanizing and composting method and apparatus - Google Patents

Abstract

A method and apparatus for processing and recycling a waste biomass, particularly urban waste which has been sorted at source, using interactive and parallel biomethanizing (2) and composting (3) lines to which the waste (4) is fed by a suitable preprocessing and conveying unit (1).

Description

 INTEGRATED BIOMETHANIZATION AND COMPOSTING PROCESS AND INSTALLATION

DESCRIPTION

The present invention relates to a method and its implementation, providing the conditions for synergistic integration of the biological processes of biomethanization and composting, with a view to their application in the field of treatment and recycling of waste biomass, in particular of the organic fraction of urban waste sorted at source and collected selectively.

An area in which the processes mentioned have been or are still most of the time operated separately, sometimes consecutively, but never in a parallel and interactive manner, within the meaning of the present claims.

The present process applies equally to the techniques of continuous or semi-continuous biomethanization, and of so-called accelerated composting, for example: in a silo, silo-corridor or rotary bioreactor.

Its implementation leads to a substantial improvement in the biological and energy yields of the techniques mentioned, the integration of which simultaneously makes it possible to widen their processing capacity to the full spectrum of the biomass of waste, and the minimization or even the elimination of their respective releases to the environment.

- Claims 1 to 3 respectively establish the general concept, the main interactive factors and the associative condition of the treatment routes which determine the invention. - The general diagram of the process (Figure 1), represents a pre-treatment unit (1) supplying a biomethanization line

(2) and composting (3) with -waste (4).

- The liquid effluent and the residual biomethanization sludge (5) are injected into the composting line, while the water or other liquid (6) necessary for the balance of the system, is returned to it at the level of the line of biomethanization whose products are respectively biogas (7), which will provide all or part of the process energy, and the solid and stabilized fraction of its effluent (8) whose intrinsic properties make it possible to envisage recovery in the food industry.

- If the biomethanization line stops, its effluent injected into the composting line can be temporarily replaced by water, thus avoiding interrupting the production of compost (9).

- Said diagram finally shows that the undesirable (10) are eliminated at the head of the process, at the level of the pre-treatment unit, which fulfills in this respect a general protection function of the installations.

Through a specially designed pre-treatment and routing unit, the claimed process responds flexibly to the uncertainty that characterizes the qualitative distribution of waste over time, by allowing the largest instantaneous transfer of compatible materials from one treatment line to the other, thus making the best use of their complementarities, their complementarities and their respective carrying capacities.

In addition, this unit has a special arrangement for adapting to the predominant nature of the waste present, which can be alternately woody and coarse or fine and wet, by reversing the order of engagement of its packaging members. - Claims 4 and 5 respectively establish the concept and the functional potentialities of the pre-treatment unit defined in the present invention.

- Figures 2 _Λ and 2 show schematically and without limitation the two operational variants characterized by a different order of engagement of the classification bodies (1.1) and granulo-trigger reduction (1.2) of said unit. These figures also show how the pre-treatment by-products constituted by the juices (1.3) and the materials with low ganulometry are separated and conveyed (l.- _j preferably referred to biomethanization because of their absence of structure, as well as the way in which the residual solid fraction (1.5) is partly routed directly to composting and partly recycled according to a retroactive loop (1.6) allowing to act on the distribution of flows.

- Buffer storage (1.7) can be made necessary in various places, depending on the conditions encountered in the supply of waste and according to the particularities presented by the particular techniques of biomethanization and composting engaged.

According to the claimed process, the conditions for the interactive management of the two processing lines are achieved by the direct cooperation of the pre-processing unit described, with two separate functional sub-assemblies called transfer modules, and arranged at the head of each. processing lines.

The purpose of these modules is to manage the interactivity of said treatment lines and to produce the necessary interfaces between the pre-treatment unit and the particular biomethanization and composting systems used.

Claims 6 and 7 define said transfer modules and their main functions.

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•La figure 1 montre encore comment le rapport est établi entre l'unité de pré-traitement et chacun des procédés techniques, par l'intermédiaire de ces modules,' dont le premier (2.1) initialise un ou plusieurs bioréacteurs (2.2) de la ligne de biomethanisation et réalise 1'interractivité de ladite ligne avec celle du compostage par l'intermédiaire d'un second module (3.1), lequel initialise à son tour le procédé spécifique ÔXJL ^€ compostage (3.2) attaché à cette dernière ligne.Follow the cifco

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FIG. 1 also shows how the relationship is established between the pre-treatment unit and each of the technical processes, via these modules, 'the first of which (2.1) initializes one or more bioreactors (2.2) of the biomethanization line and performs the interactivity of said line with that of composting by means of a second module (3.1), which in turn initiates the specific process ÔXJL ^€ composting (3.2) attached to this last line.

By the functions it brings together, the transfer module of the biomethanization line is the main seat of the biological and technical management of the claimed process as well as the place of its energy management.

To reduce the influence of the heterogeneity of the waste on the conditions of biomethanisation, a conditioning step precedes the introduction of the materials into the bioreactor, with the double effect of normalizing them and isolating a residual liquid fraction.

Similarly for the extraction of digested materials, ^~ u) do or more conditioning steps also allow to isolate the liquid fraction and separately treat the solid residue.

According to this conception, the biological, hydraulic and physical regulations of the whole process are operated through the differential - and integrated - management of the generated liquid fractions, which are also the heat transfer fluids which transfer to the incoming materials 10H energy ^ ce // c thermal ^ contained ^ in outgoing materials and dissipated ^ by the aforementioned packaging elements.

Claim 8 specifies and lists the functions specifically characterizing the transfer module of the biomethanization line. FIG. 3 represents a non-limiting diagram of said module showing the relationships established between its respective bodies for conditioning and introducing materials in the solid (2.1.) And liquid (2.12) forms in the bioreactor (s), and extracting and packaging ^'of Contents

⁽ * ^• g) digested <- ¹ "whose fraction not recycled in the bioreactor by the retroactive loop (2.1 ₄ ) is conveyed to the composting line after having given up its heat to the incoming materials in an exchanger (2.1 s).

The figure also shows that additives (2-t-.) Can be dosed in the module to act on the biochemical sequence

déchets et combinaison de déchets organiques, elle possède dans le contexte urbain, une application privilégiée dans la mesure où, contrairement au compostage et à la biomethanisation envisagés individuellement, elle peut traiter localement, complètement et économiquement toute la fraction organique générée.

waste and combination of organic waste, it has a privileged application in the urban context insofar as, unlike composting and biomethanization envisaged individually, it can treat locally, completely and economically all the organic fraction generated.

Indeed, through the play of complementarities developed between the two processes, it is no longer necessary to look outside the waste collection departments for co-substrates which would generate, in the event of an exclusive use of composting in urban areas, an increase in the total mass of waste to be treated on the order of a quarter to a third, accompanied by the corresponding transport costs.

- Claims 9 and 10 respectively establish the characteristics preferably attached to the pre-processing and routing unit as well as to the transfer modules of each of the processing lines, in the application and the implementation of the method for the treatment and recycling of the organic fraction of urban waste sorted at source and collected selectively.

Claims

1. Method for the treatment and recycling of waste biomass, characterized in that it implements in parallel and interactively, a biomethanization treatment line and a composting treatment line, between which the waste is distributed thanks to the help of an appropriate pre-treatment and routing device, which also has the means to eliminate unwanted or non-compliant materials. 2. Method according to claim 1, characterized in that the liquid effluent and the residual sludge from the biomethanization are introduced into the composting line, so as to compensate for its losses by evaporation while stimulating its microbiology, and that the water or any other liquid necessary for the system are returned to it at the level of the biomethanization line. 3. Method and installations intended for its implementation according to claims 1 and 2, characterized in that the temporary shutdown of one of the processing lines does not affect the operation of the other. 4. Method and installations intended for its implementation according to claim 1, characterized in that the pre-treatment device constitutes a separate functional unit having, in addition to the means for eliminating undesirable materials, at least two organs for classification and reduction in particle size reduction: The first has the function of filtering the materials of smaller particle size as well as the juices with a view to their biomethanization, and the second to standardize the particle size of the residual materials. 5. Method and installations for its implementation according to claims 1, 3 and, characterized in that the pre-treatment device ^' has, in addition to the possibility of conveying the materials without nuisance to their respective treatment lines, that to regulate the degrees of conditioning and distribution, including over time, of these materials, in particular by bringing into play, alone or in combination, the following means: a) the partial or total recirculation of materials between the classification and size reduction mentioned; b) the modification of the particle size parameters of said organs; c) the reversal of the order of intervention of said bodies; d) the use of buffer storage. 6. Method and installations for its implementation according to claim 1, characterized in that the biomethanization line is composed at least of a continuous or semi-continuous type bioreactor, implemented by a specific functional sub-assembly called transfer module, bringing together all of the feed functions of the digester (s), as well as the means for bringing said line into interaction with that of composting. 7. Process and installations intended for its implementation according to claims 1 to 5, characterized in that the incorporation of the effluents from the biomethanization into the materials to be composted as well as the initiation of the fermentation are carried out in a device also modularized, can lead the process to the stage of complete hygienization of the substrate, and that said process is then completed by an appropriate composting technique. 8. Method and installations intended for its implementation according to claims 1 and 6, characterized in that said transfer module comprises at least the organs: a) of packaging and distint introduction of the solid and liquid fractions of the substrate in the (s) bioreactor (s); b) extraction, separation of the solid and liquid phases, as well as conditioning and transfer of the digested materials; c) transfer to incoming materials of heat from outgoing materials and the functioning of the pre-

as well as the means of introducing additional additive substances into the material flows, in particular to correct the course of the treatment process or the formula of its products. 9. Process and installations intended for its implementation for the joint treatment of food and plant waste from so-called selective or assimilated collections according to claims 6, 1 and 8, characterized in that the organs for pre-treatment of these materials can be constituted as appropriate by a calendering or sieving device with adjustable or interchangeable hopper, combined with a grinding device also having a means of adjusting its particle size, so that the introduction of waste is possible by a one way or the other depending on their initial nature and that their packaging according to the needs of the process can be easily adjusted. 10. Method and installations intended for its implementation for the joint treatment of food and plant waste according to claims 6, 7 and 8, characterized in that the operations of packaging and introduction of the materials e α are carried out simultaneously by a _j è mechanical extrusion device comprising screw, knives, dies, that extraction and solid 1'effluent stabilization are successively carried out by a press and a of the same granular screw principle, optionally disposed on the same axis, that the management of the liquid fractions is ensured by a dosing pump, and the incorporation of the liquid effluents and the sludge into the materials to be composted is ensured by a section of rotary drum specially adapted to this function.