FOR ITS USE IN HYDROPONIC PLANT CULTURE

Technical field

The present invention generally relates to the transformation of organic waste into a nutrient solution (or liquid fertilizer) containing nutrients for hydroponic plant culture. The invention in particular relates to a process of transforming organic waste (especially organic household waste such as kitchen food waste) into a nutrient solution containing nutrients for hydroponic plant culture, and to uses of the nutrient solution produced in accordance with the invention for hydroponic plant culture, in particular for the production of vegetables or fruits. The invention further relates to a process of growing vegetables or fruits in hydroponic culture, an organic waste processing system, as well as a hydroponic farming structure for growing vegetables or fruits.

Backqround and related prior art

Various attempts have been made in the art to recover and transform organic waste for the purpose of producing nutrient solutions and like organic fertilizers for plant culture, and thereby replace chemically synthesized fertilizers. Solutions have especially been proposed for use in hydroponic plant culture (also referred to as “bioponics” due to the organic origin of the materials used to produce the necessary nutrient solution). One advantageous source of organic fertilizers is organic food waste, organic products (vegetables, fruits, etc.) that are unfit for human consumption, rotten vegetables and fruits, and raw organic material. Such organic waste basically contains all essential nutrients for plant growth. The transformation of such organic waste into a suitable nutrient solution for hydroponic plant culture accordingly represents an effective way of biomass recycling.

A known technique is disclosed in U.S. Patent No. US 8,327,581 B2, which disclosure is incorporated herein by reference. This patent publication discloses a method for producing a nutrient solution for hydroponic plant culture utilizing an organic material. More specifically, there is provided a method for producing a biomineral- containing nutrient solution comprising (i) gradually adding an organic material to water, (ii) fermenting the resulting mixture under aeration such as to establish a microbial ecosystem, and (iii) decomposing organic nitrogen in the organic material to nitric acid. The organic material is added to water in an amount of 0.05 to 1 g per liter of water once every one to seven days. The process aims to establish a microbial ecosystem restraining the generation of intermediate decomposition products that would be harmful to plant growth and enabling direct addition of organic materials to the nutrient solution. However, this process of establishing and maintaining a microbial ecosystem is long, fastidious and hard to maintain on the long run. It does not enable the transformation of significant quantities of unspecific organic food waste, but only small quantities of specific raw organic materials. The inoculation of the fermentation environment with an exogenous microorganism source such as soil or bark compost beside the organic material supply is not excluded. This continuous biomineralization process of the organic material directly in contact with plants does not allow the separation of the fertilizer production process from the plant growing process and does not create an optimal environment for the fermentation process. Therefore, increasing the fermentation capacity cannot be achieved. The addition of pesticides and antiseptics to the nutrient solution to avoid damages and harm to plant culture, as well as the presence of intermediate decomposition products being harmful for the plant culture cannot be excluded. This process of biomass recycling is not appropriate to transform the daily quantity of unspecific organic food waste from a typical 5-person family household (which can easily amount to 3 kg of organic waste per day) into a liquid fertilizer for hydroponic plant culture.

U.S. Patent No. US 5,810,903 A discloses a thermophilic, aerobic fermentation process for conversion of a variety of organic waste materials into useful end products, including wet products that may for example be directly fed to animals or used as liquid fertilizers, soil conditioners or soil amendments. No specific reference to the use of such wet products for hydroponic plant culture is however contemplated. The fermentation process is initiated over a period of from about 2 to 6 days by application of external heat to an uninoculated oxygenated aqueous mixture of the waste material, and that utilizes thermophilic microorganisms naturally present in the waste material to initiate the fermentation. More specifically, fermentation of the aqueous mixture takes place in multiple large-capacity fermenters that are each provided with a source of external heat to bring the temperature of the aqueous mixture to about 55°C to 85°C during fermentation. No particular preprocessing of the organic waste materials is contemplated beyond macerating the organic waste materials in water using a hydropulser prior to fermentation to produce an aqueous mixture preferably containing from about 5% to about 20% total solids by weight. A centrifuge (or alternatively a decanter or filter) is also contemplated to optionally reduce the water content of the fermented product to obtain a wet product comprising about 35% by weight solids. Water removed from the aqueous mixture of fermented waste matter is preferably recirculated to the hydropulser to be slurried with waste matter being macerated in the hydropulser. This process is not suitable for the production of an adequate nutrient solution for hydroponic plant culture.

U.S. Patent Publication No. US 2019/0194081 A1 discloses nutritional compositions for plants and soils, and a method of producing the same, which nutritional compositions are produced by autothermal thermophilic aerobic bioreaction of poultry manure. More specifically, raw poultry manure (such as raw chicken manure) is mixed with citric acid and water to form a homogenous slurry. This slurry is then mixed with water to elevate the moisture level of the slurry to a moisture range from about 84% to 87% moisture and heated by steam to about 65°C for a minimum of one hour in order to break down the manure into fine particles and fully homogenize the feedstock slurry for further processing. In this process, pathogens that are found in the manure are killed and native thermophilic bacteria are activated. The homogenized feedstock slurry is then sent to a centrifuge to separate the solid fraction from the liquid fraction of the slurry. The solid fraction is dried to about 12% or less moisture and used to produce a dry fertilizer product. The liquid fraction, on the other hand, is sent to an aerobic bioreactor where native microorganisms are cultivated. Thermophilic fermentation occurs in the aerobic bioreactor for a minimum of one day to a maximum of about eight days, at a uniform minimum temperature of about 55°C. The fermented liquid product from the aerobic reactor is subsequently managed in either of two ways. The first is a standard product process, while the second is a speciality product process. Both products are formulated with supplemental nitrogen and potassium and filtered directly into storage or packaging. For the standard product process, the formulated liquid product is simply filtered and transferred into a storage tank. For the speciality product process, the formulated liquid product is flash pasteurized, filtered and then further formulated for special use, e.g. with custom microbes, after which it is transferred into storage or packaging. One will therefore appreciate that the process of US 2019/0194081 A1 is based solely on the use of poultry manure as feedstock and specifically requires heating the slurry with steam to break down the manure into fine particles, as well as separation of the solid and liquid fractions of the resulting feedstock slurry to subject only the liquid fraction to aerobic fermentation. This process is not therefore directly applicable to process organic waste as typically produced by a household.

U.S. Patent Publication No. US 2016/0037737 A1 discloses a closed loop compost tea brewing system with a hydroponic reservoir and a compost tea brewing assembly configured to brew compost tea, which compost tea brewing assembly includes a tea brewing reservoir. Strictly speaking, this system is wholly unable to process organic waste per se and is merely based on the use of compost that is steeped in water for an extended period of time, such as 24 to 48 hours, to produce the desired compost tea. No particular fermentation process is put into practice in this case, nor any pasteurization. In effect, the relevant compost tea is simply fed directly from the tea brewing reservoir to the hydroponic reservoir, and recirculated back from the hydroponic reservoir to the tea brewing reservoir to form a closed loop arrangement.

Several other systems to transform and/or recycle the biomass of organic household waste have been developed and commercialized. Some systems involve fermentation of the organic raw material alone, which often is continuous and produces fertilizer incompatible with their direct use in hydroponics, especially for hydroponic plant culture at a household scale. Other systems merely solve the problem of storing the organic waste of a household by reducing the volume of waste, but they neither involve fermentation of the organic material, nor the production of a nutrient solution or like liquid fertilizer that is directly usable for hydroponic plant culture.

Actually, the development of new systems and processes for recycling the biomass of organic household waste into a suitable nutrient solution for hydroponic plant culture remains a real challenge. Especially, such new systems and processes have to duly take into consideration the typical constraints of households in terms of available space for storage and processing of the relevant organic waste, as well as for the relevant hydroponic plant culture. Summary of the invention

The invention is made in view of the aforementioned problems and drawbacks in the related art.

A general aim of the invention is to provide a process and system that can suitably transform organic waste into a nutrient solution containing nutrients for hydroponic plant culture.

More specifically, an aim of the present invention is to provide such a solution that can adequately process organic waste produced by a typical household.

A further aim of the invention is to provide such a solution that enables optimal recovery of organic waste.

Another aim of the invention is to provide such a solution that allows the production of a nutrient solution (or liquid fertilizer) that can suitably be used for hydroponic plant culture, in particular for the purpose of growing vegetables or fruits.

Yet another aim of the invention is to provide such a solution that is scalable and can be adapted to the relevant household size and amount of organic waste being produced by a household.

An aim of the invention is also to provide a suitable process of growing vegetables or fruits in hydroponic culture, which process does not necessitate use of exogeneous nutrient solutions.

Yet another aim of the invention is to provide such a solution that allows efficient implementation of a hydroponic farming structure for growing vegetables or fruits and that facilitates operation thereof by a typical household.

These aims are achieved thanks to the solutions defined in the claims.

There is accordingly provided, in accordance with an aspect of the present invention, a process of transforming organic waste, with the exclusion of manure, into a nutrient solution containing nutrients for hydroponic plant culture, the features of which are recited in claim 1 , namely such a process that comprises the following steps:

(a) collecting and preprocessing the organic waste;

(b) subjecting liquid and solid fractions of the preprocessed organic waste to liquid composting and fermentation at room temperature to produce a fermented liquid containing plant-usable nutrients; and

(c) subjecting a selected part of the fermented liquid to pasteurization, separately from the liquid composting and fermentation, to produce a nutrient solution containing said plant-usable nutrients. One will appreciate that, according to the invention, one achieves separation between the liquid composting and fermentation, on the one hand, and actual usage of the produced liquid fertilizer as nutrient solution for plant growing, on the other hand. This is achieved thanks to a spatial separation of the liquid composting and fermentation process and plant growing. In other words, this spatial separation ensures that distinct chemical environments can be maintained and optimized for composting/fermentation and plant growing. This further allows for a higher processing capacity in that fermentation tanks can be used as storage vessels to produce and supply nutrients only when necessary.

The pasteurization process ensures that food-safety requirements according to relevant national and international standards can appropriately be met. Indeed, typical organic household waste may potentially include uncooked animal products (such as uncooked poultry meat or raw eggs for instance), which may include Salmonella species, Listeria monocytogenes (L monocytogenes), Escherichia coli (E. coli), and other bacterial pathogens that absolutely need to be eliminated. Pasteurization in particular ensures compliance with microbial standards on L monocytogenes, E. coli 0157:H7, and Salmonella species to ensure food-safety requirements for growing food.

Preferably, the liquid composting and fermentation are carried out in an aerobic environment involving active aeration of the fermented liquid.

In particular, the liquid composting and fermentation are carried out based on a naturally established microbial community derived from the organic waste, doing away with the necessity to introduce any particular microbial strain.

In accordance with a particularly preferred embodiment, the liquid composting and fermentation are carried out in successive batch cycles each involving feeding a liquid fermentation stage with a selected quantity of preprocessed organic waste. Each batch cycle may especially be a multi-day cycle, e.g. 10 to 14 days, possibly more. In particular, each batch cycle preferably lasts a couple of weeks (i.e. of the order of 14 days) or more in order to allow establishment and maintenance of a suitably stable microbial community.

By way of preference, the liquid composting and fermentation are carried out in two or more fermentation tanks that are fed sequentially with the selected quantity of preprocessed organic waste. The selected quantity of preprocessed organic waste is advantageously fed to the liquid fermentation stage at a rate of approximately 1 kg per day.

Preprocessing of the organic waste may in particular include removing excess moisture from the organic waste. This excess moisture can conveniently be recovered and used in the context of the liquid composting and fermentation process. Excess moisture can be removed by any appropriate means, including e.g. squeezing or centrifugation.

Preprocessing of the organic waste may also include squeezing of the organic waste, be it for removing excess moisture as specified above and/or for the purpose of reducing the volume of the relevant organic waste.

Preprocessing of the organic waste may further include chopping of the organic waste into grinded organic waste components, which favours more efficient composting and fermentation of the organic waste.

By way of preference, the process of the invention further comprises the step of drying the preprocessed organic waste and, even more preferably, the step of temporarily storing the dried preprocessed organic waste prior to subjecting it to the liquid composting and fermentation.

With regard to the aforementioned processing in successive batch cycles, the dried preprocessed organic waste is especially temporarily stored pending completion of each batch cycle. In other words, drying and temporary storage of the dried preprocessed organic waste is optionally carried out while liquid composting and fermentation of an ongoing batch cycle are being carried out and pending completion of such batch cycle.

The process may further comprise the step of removing dried preprocessed organic waste exceeding a temporary storage capacity, which may be necessitated in case the amount of organic waste to be processed exceeds a nominal processing capacity. In other words, dried material could potentially be removed and still be used as additional long-term composting fertilizer for outdoor soil-grown plants.

Drying of the preprocessed organic waste may advantageously be performed by active convective air drying. Drying of the preprocessed organic waste may further be assisted by ultrasound, namely by using ultrasound to break down the organic waste on a microscopic level, leading to destruction of dehydration barriers, which facilitates water extraction from the organic waste and improves the drying speed. By way of preference, pasteurization is carried out by bringing the fermented liquid to a temperature comprised between 70°C and 95°C. In particular, with due consideration of relevant food-safety guidelines, pasteurization may be carried out by bringing the fermented liquid to a temperature of approximately 75°C to 80°C for a duration comprised between 15 to 20 seconds to minimize energy consumption, while maintaining a suitable pasteurization efficacy and reasonable processing speed.

Pasteurization of the fermented liquid may especially include feeding the fermented liquid through a heat exchanger. By way of preference, the heat exchanger is configured such that heat from the fermented liquid being subjected to pasteurization is partly recovered in order to preheat the fermented liquid.

The process of the invention may especially be applied to the transformation of organic household waste, in particular kitchen food waste.

The process may furthermore comprise the step of adjusting the nutrient solution for use as nutrient solution for hydroponic plant culture.

In particular, the step of adjusting the nutrient solution preferably includes adjusting a pH of the nutrient solution, especially to a value comprised withing a range of 5.5 to 6.5. Adjustment of the pH of the nutrient solution advantageously includes decreasing the pH by selectively adding citric acid to the nutrient solution.

The process may further comprise the step of adjusting a pH of the fermented liquid during the liquid composting and fermentation, especially to a value comprised within a range of 6.5 to 8.

Dilution of the nutrient solution with tap water or rain water may also be contemplated as a further adjustment measure.

Also claimed is the use of the nutrient solution produced in accordance with the invention for hydroponic plant culture, in particular for the purpose of producing vegetables or fruits.

There is also provided a process of growing vegetables or fruits in hydroponic culture, comprising providing a hydroponic farming structure to grow vegetables or fruits, and feeding the hydroponic farming structure with a nutrient solution produced in accordance with the invention.

There is further provided, in accordance with another aspect of the present invention, an organic waste processing system for transforming organic waste, with the exclusion of manure, into a nutrient solution containing nutrients for hydroponic plant culture, the features of which are recited in independent claim 34, namely such a system including: a preprocessing stage configured to preprocess the organic waste; a liquid fermentation stage configured to subject liquid and solid fractions of the preprocessed organic waste to liquid composting and fermentation at room temperature to produce a fermented liquid containing plant-usable nutrients; and a pasteurization stage, separate from the liquid fermentation stage, configured to subject a selected part of the fermented liquid to pasteurization to produce a nutrient solution containing said plant-usable nutrients.

Preferably, the liquid fermentation stage is an aerobic fermentation stage comprising at least one fermentation tank including an active aeration device.

In accordance with a particularly preferred embodiment, the liquid fermentation stage may especially be configured to carry out liquid composting and fermentation of the preprocessed organic waste in successive batch cycles each involving feeding the liquid fermentation stage with a selected quantity of preprocessed organic waste. In this context, the liquid fermentation stage preferably comprises two or more fermentation tanks that are fed sequentially with the selected quantity of preprocessed organic waste. The liquid fermentation stage advantageously has a capacity sufficient to receive a selected quantity of preprocessed organic waste that is fed at a rate of approximately 1 kg per day. The liquid fermentation stage may especially be configured such that each batch cycle lasts multiple days, e.g. 10 to 14 days, possibly more. In particular, the liquid fermentation stage is preferably configured such that each batch cycle lasts a couple of weeks (i.e. of the order of 14 days) or more in order to allow establishment and maintenance of a suitably stable microbial community.

The preprocessing stage may in particular be configured to remove excess moisture from the organic waste. The preprocessing stage may in particular include a squeezer, a compacter, or a centrifugal unit. Excess moisture removed by the processing stage may especially be recovered in a collection chamber of the preprocessing stage for feeding to the liquid fermentation stage.

The preprocessing stage may also be configured to squeeze the organic waste, be it for removing excess moisture as specified above and/or for the purpose of reducing the volume of the relevant organic waste. The preprocessing stage may further be configured to chop the organic waste into grinded organic waste components, which favours more efficient composting and fermentation of the organic waste.

By way of preference, the organic waste processing system of the invention further comprises a drying stage configured to dry the preprocessed organic waste. Even more preferably, the organic waste processing system further comprises a temporary storage stage configured to temporarily store the dried preprocessed organic waste prior to feeding it to the liquid fermentation stage.

With regard to the aforementioned processing in successive batch cycles, the temporary storage stage may especially be configured to temporarily store the dried preprocessed organic waste pending completion of each batch cycle.

The temporary storage stage may in particular include a removable storage drawer configured to receive the dried preprocessed organic waste, thus allowing removal of dried preprocessed organic waste exceeding a temporary storage capacity in case of need.

The drying stage may advantageously be an active convective air dryer. The drying stage may further include one or more ultrasound transducers to assist and speed up the drying operation.

By way of preference, the pasteurization stage is configured to bring the fermented liquid to a temperature comprised between 70°C and 95°C during pasteurization. Even more preferably, the pasteurization stage is configured to bring the fermented liquid to a temperature of approximately 75°C to 80°C for a duration comprised between 15 to 20 seconds during pasteurization.

The pasteurization stage may in particular include a heat exchanger through which the fermented liquid coming from the liquid fermentation stage is fed. More specifically, the heat exchanger may be configured such that heat from the fermented liquid being subjected to pasteurization is partly recovered in order to preheat the fermented liquid.

Further claimed is a hydroponic farming structure for growing vegetables or fruits, comprising an organic waste processing system according to the invention supplying a nutrient solution to one or more hydroponic planting receptacles.

Preferably, such hydroponic farming structure comprises a plurality of modular units each comprising one hydroponic planting receptacle, which modular units are assemblage one with the other. Further advantageous embodiments of the invention form the subject-matter of the dependent claims and are discussed below.

Brief description of the drawings

Other features and advantages of the present invention will appear more clearly from reading the following detailed description of embodiments of the invention which are presented solely by way of non-restrictive examples and illustrated by the attached drawings in which:

Figure 1 is a schematic illustration of a closed-loop cycle enabled by the invention;

Figure 2 is a schematic flowchart of a process of transforming organic waste into a nutrient solution for hydroponic plant culture in accordance with a preferred embodiment of the invention;

Figure 3 is a schematic diagram of a liquid fermenter with active aeration as used in the context of a preferred embodiment of the invention;

Figure 4 is a schematic diagram of an organic waste processing system in accordance with an embodiment of the invention;

Figure 5 is a schematic illustration of a modular hydroponic farming structure for growing vegetables or fruits, comprising an organic waste processing system according to the invention that supplies a nutrient solution to multiple hydroponic planting receptacles;

Figure 5A is a schematic illustration of a modular unit comprising one hydroponic planting receptacle as used in the context of the modular hydroponic farming structure of Figure 5;

Figure 5B is a schematic illustration of the modular unit of Figure 5A with the hydroponic planting receptacle being removed for the sake of illustration;

Figures 6A and 6B are perspective views of an organic waste processing system in accordance with a preferred embodiment of the invention;

Figure 7 is an exploded perspective view of the organic waste processing system of Figures 6A-B;

Figure 8 is a perspective view of a preprocessing stage (or apparatus) forming part of the organic waste processing system of Figures 6A-B and 7;

Figure 9 is an exploded partial perspective view showing components of a compactor device forming part of the preprocessing stage of Figure 8; Figure 10 is a perspective view of a shredder device likewise forming part of the preprocessing stage of Figure 8;

Figure 10A is an exploded view of the shredder device of Figure 10;

Figures 11 A and 11 B are two perspective views of a collector device also forming part of the preprocessing stage of Figure 8;

Figure 11C is a front view of the collector device of Figures 11A-B;

Figure 11 D is a cross-sectional view of the collector device of Figures 11A-C taken along sectional plane A-A shown in Figure 11C;

Figure 12 is a cross-sectional view of the preprocessing stage of Figure 8 taken a sectional plane coinciding with sectional plane A-A;

Figure 13 is a perspective view of a drying stage (or apparatus) forming part of the organic waste processing system of Figures 6A-B and 7;

Figure 13A is a perspective view of the drying stage of Figure 13 showing an exhaust filter in a removed position;

Figures 13B and 13C are exploded perspective views of the drying stage of Figure 13;

Figure 13D is an exploded perspective view of a lower section of the drying stage of Figure 13;

Figures 14A and 14B are perspective views of a temporary storage stage forming part of the organic waste processing system of Figures 6A-B and 7;

Figure 14C is an exploded perspective view of the temporary storage stage of Figures 14A-B;

Figure 14D is a partial perspective view of the underside of the temporary storage stage with portions thereof removed to reveal components of the temporary storage stage;

Figure 15A is a perspective view of a liquid fermentation tank forming part of the organic waste processing system of Figures 6A-B and 7, portions of the liquid fermentation tank being omitted for the sake of illustration;

Figure 15B is a side view of the liquid fermentation tank of Figure 15A;

Figure 15C is a cross-sectional view of the liquid fermentation tank of Figures 15A-B taken along sectional plane B-B shown in Figure 15B;

Figure 16 is an exploded perspective view of a pasteurization stage forming part of the organic waste processing system of Figures 6A-B and 7; and Figure 16A is a partial perspective view of a cross-section of the pasteurization stage of Figure 16.

Detailed description of embodiments of the invention

The present invention will be described in relation to various illustrative embodiments. It shall be understood that the scope of the invention encompasses all combinations and sub-combinations of the features of the embodiments disclosed herein.

Figure 1 is a schematic illustration generically showing a closed-loop cycle that is enabled by the present invention. More specifically, organic waste generated by consumers is recovered and transformed into a nutrient solution (or liquid fertilizer) that is used for hydroponic plant culture, in particular for growing vegetables, such as leaf vegetables, fruits or the like. In effect, the present invention aims to provide a suitable solution to primarily address organic waste recovery and ensure supply of an adequate nutrient solution for hydroponic plant culture, as circled by dashed lines in Figure 1. The invention is based on the observation that organic waste contains organic and mineral nutriments suitable for ensuring sustainable plant growth.

In effect, aiming for the closed-loop cycle pictured in Figure 1 basically amounts to allowing each household to turn itself into its own farming operation, enabling distributed farming and reducing the number of typical interactors active in the production, distribution, transport, and retail of edible plant products. Each consumer is thus turned into a producer capable of growing its own vegetables or fruits by converting organic waste back to useful nutrients.

A key element of the present invention is therefore the relevant process designed to transform the organic waste into a nutrient solution containing nutrients for hydroponic plant culture. Figure 2 is a schematic flowchart of such a process in accordance with a preferred embodiment of the invention.

As an initial step S100 of the process, organic waste must be suitably collected for processing. In this context, assuming a typical household, the organic waste would primarily consist of usual kitchen food waste, including meal leftovers, rotten fruits and/or vegetables, and other organic waste generated by the household, such as garden plant waste. In effect, any organic waste suitable for usual composting could come into consideration. Manure (be it of animal or human origin) is excluded as a possible organic waste input as processing thereof requires specific measures to ensure complete compliance with food-safety standards.

In the context of the present invention, relevant organic waste may especially include:

- raw food waste, including: inedible vegetable parts (such as bell pepper stems, citrus seeds, onion skins, etc.); inedible vegetable and fruits skins (such as banana peels, carrot or potato skins, watermelon rind, etc.); nut shells (such as peanut or walnut shells, etc.); egg shells, cheese, fish skins and bones; unwanted meat cuttings (such as tendons, fats, skins, bones (chicken bones only); fruit juices past their use-by dates;

- cooked food waste including: cooked food leftovers; chicken bones; coffee grounds;

- green waste including: old/dry plant leaves; non-wooden garden cuttings; fresh-cut lawn grass;

- other waste types including: newspapers; tissues; and cardboard (pre-shredded).

In a subsequent step S200 of the process, the organic waste is preprocessed prior to subsequent processing, namely fermentation at step S300 followed by pasteurization at step S400. Preprocessing could in effect include various preprocessing measures, including mechanical preprocessing operations such as removal of excess moisture, squeezing/compacting of the organic waste, and/or chopping of the organic waste into grinded organic waste components.

Removal of excess moisture from the organic waste may be carried out in different ways, including by squeezing of the organic waste and/or by centrifugation. The main goal is to extract excess moisture and thereby allow some reduction of the volume of the organic waste. Excess moisture removed at step S200 may in effect be recovered and used in the context of the subsequent liquid composting and fermentation step S300, bearing in mind that the extracted moisture contains valuable organic and mineral nutriments that are worth being recovered.

Squeezing of the organic waste may be carried out by means of any suitable compactor device that can subject the organic waste to a compacting and squeezing operation, achieving a reduction of the volume of the organic waste.

Preferably, preprocessing of the organic waste includes chopping of the organic waste into grinded organic waste components. This is particularly useful in that efficiency of the subsequent liquid composting and fermentation step S300 is facilitated and improved. This further facilitates the automatic or semi-automatic dosing of organic waste material to the subsequent composting and fermentation step S300. Chopping of the organic waste may likewise be carried out by means of any suitable chopper, grinder or shredder device capable of processing organic waste.

In effect, all of the aforementioned preprocessing measures could conveniently be implemented in one, single preprocessing stage or apparatus combining all functionalities, as shown e.g. in Figures 8-12 to be discussed later.

According to the invention, liquid and solid fractions of the preprocessed organic waste is then subjected to a liquid composting and fermentation operation at room temperature at step S300. Liquid composting and fermentation at step S300 is carried out at room temperature, i.e. without the provision of any external heat source. The purpose of this step S300 is to break down the preprocessed organic waste into plant- usable nutrients and produce a fermented liquid containing said plant-usable nutrients. By way of preference, liquid composting and fermentation are carried out in an aerobic environment, namely in the presence of oxygen. In this case, step S300 thus involves active aeration of the fermented liquid.

Figure 3 is a schematic illustration of a liquid fermenter (or liquid fermentation stage) 300 comprising a fermentation tank 30 incorporating an active aeration device 35 capable of injecting air into the liquid being subjected to fermentation. While not specifically shown in Figure 3, one will appreciate and understand that a suitable supply of water will be provided to feed the liquid fermentation stage 300 with the desired quantity of water necessary for the liquid fermentation process. No particular thermal insulation of the fermentation tank 30 is contemplated to ensure that fermentation can suitably take place at room temperature. While the fermentation process inherently generates heat, such heat is simply transferred to the surrounding environment.

By way of preference, the liquid composting and fermentation step S300 is carried out based on a naturally established microbial community derived from the organic waste. In other words, no particular addition of any exogeneous microbial strain is contemplated beyond the microbial community already present in the organic waste. This being said, use of an exogenous microbial strain could be contemplated if desired.

In accordance with a particularly preferred embodiment of the invention, the liquid composting and fermentation step S300 is carried out in successive batch cycles each involving feeding a suitable liquid fermentation stage 300 with a selected quantity of preprocessed organic waste. Several batch cycles could in effect be run in sequence using multiple fermentation tanks. In particular, the liquid fermentation stage 300 preferably comprises two fermentation tanks (as shown e.g. in Figure 4) that are used in sequence. More than two fermentation tanks could potentially be used.

In accordance with a preferred embodiment of the invention, the selected quantity of preprocessed organic waste is fed to the liquid fermentation stage 300 at a rate of approximately 1 kg per day, which is normally sufficient for a typical 5-person family household. Assuming a batch cycle of e.g. ten days, that equates to total processing capacity of the order of 10 kg (equivalent to approximately 10 to 15 litres). Processing of larger quantities of organic waste could however be contemplated.

It is especially contemplated that each batch cycle lasts multiple days, in particular a couple of weeks (i.e. approx.. 14 days) or more to ensure adequate stabilisation of the microbial community and optimal decomposition of the organic waste into the desired plant-usable nutriments. In that respect, one may perfectly contemplate running several batch cycles in sequence to ensure a semi-continuous processing of the organic waste.

This being said, it may be useful to contemplate further steps to cope with the potential supply of organic waste while relevant batch fermentation cycles are underway. Especially, as shown in Figure 2, it may be desirable to additionally provide for the step of drying S250 the preprocessed organic waste and, even more preferably, the step of temporarily storing S255 the dried preprocessed organic waste prior to subjecting it to the liquid composting and fermentation step S300. With regard to the preferred embodiment shown in Figure 2, the main purpose of the additional steps S250, S255 is to ensure that preprocessed organic waste can be temporarily stored pending completion of each relevant fermentation cycle. In effect, drying allows removal of any remaining liquid component that may still be present in the preprocessed organic waste, achieving further reduction of the volume of the processed waste. Drying of the preprocessed organic waste further prevents uncontrolled composting/fermenting of the organic waste that could otherwise produce bad smells and/or multiplication of undesired and potentially dangerous microbes.

Furthermore, should the dried preprocessed organic waste ultimately reach the maximum temporary storage capacity, the dried material could potentially be removed from the system and still be used as additional long-term composting fertilizer for outdoor soil-grown plants, it being understood and appreciated that dried material is easier to handle than half-fermented, wet organic waste and has the possibility of long term storage. In particular, dry fertilizer can be generated and stored during winter times and used in spring for planting.

As schematically shown in Figure 2, one will therefore appreciate that steps S250, S255 are in effect optional in that drying of the preprocessed organic waste may only be required in the event preprocessed organic waste is to be temporarily stored pending completion of the relevant batch cycle. By way of preference, the fermentation step S300 is carried out whenever possible based on “fresh” (i.e undried) organic waste, and steps S250, S255 are only carried out in the event organic waste exceeds the relevant composting/fermentation capacity.

The drying operation S250 may be carried out in any appropriate manner. By way of preference, such drying is performed by active convective air drying, ideally under the assistance of ultrasound, namely by using ultrasound to break down the organic waste on a microscopic level. Application of ultrasound during the drying process leads to destruction of dehydration barriers, which facilitates water extraction from the organic waste and improves the drying speed.

Once the relevant fermentation cycle is completed, a selected part of the fermented liquid is subjected to pasteurization at step S400 with a view to eliminate pathogens contained in the fermented liquid, which step S400 is carried out separately from the liquid composting and fermentation at step S300. This preferably includes bringing the fermented liquid to a temperature comprised between 70°C and 95°C during the pasteurization step S400. A pasteurization temperature of 72°C has shown to be sufficient in practice. By way of preference, in order to have a sufficient safety margin, pasteurization at step S400 involves bringing the fermented liquid to a temperature of approximately 75°C to 80°C for a duration comprised between 15 to 20 seconds. This ensures a suitable pasteurization efficacy, at a reasonable processing speed, while minimizing energy consumption.

Figure 4 is a schematic diagram of part of an organic waste processing system in accordance with an embodiment of the invention. Pictured in Figure 4 is a liquid fermentation stage 300 including first and second fermentation tanks 30-1 , 30-2 and an associated pasteurization stage 400 designed to process a selected part of the fermented liquid coming from either one of the fermentation tanks 30-1, 30-2 and subject it to pasteurization in order to derive the desired amount of nutrient solution that may be stored in a corresponding nutrient solution tank (not shown) for further use. The preprocessing stage used to preprocess the organic waste prior to feeding thereof to the liquid fermentation stage 300 is not specifically shown in Figure 4.

By way of illustration, each fermentation tank 30-1 , 30-2 has a capacity of the order of 30 litres, which capacity is selected with a view to process of the order of 10 kg of organic waste during each fermentation cycle. The ratio of processable organic waste over fermentation tank capacity is therefore of the order of 1/3 kg/I.

While not specifically shown in Figure 4 (but illustrated in Figures 15B-C discussed hereafter), each fermentation tank 30-1, 30-2 includes a particle filter designed to hold solid particles in each fermentation tank 30-1, 30-2. A pump P is coupled to the fermentation tanks 30-1 , 30-2 via output valves VFM, VF2-I, to selectively feed the desired amount of fermented liquid to the pasteurization stage 400 via a further valve VHX located downstream of the pump P. The pasteurization stage 400 preferably includes a heat exchanger 45, coupled to an associated heater 40, through which the selected share of fermented liquid is fed during pasteurization.

More specifically, it will be appreciated that liquid composting and fermentation will take place at room temperature in one of the fermentation tanks 30-1, 30-2 at a time, and this for as long as the relevant fermentation cycle is supposed to last (e.g. 14 days). During that time, organic waste is supplied to the other fermentation tank. Once the desired fermentation cycle is completed, a selected portion of the fermented liquid can be fed to the pasteurization stage 400 by opening the relevant valves VHX and VFM or VF2-I (depending on from which of the fermentation tanks 30-1 , 30-2 liquid is to be drawn) and by activating pump P to draw fermented liquid from the relevant fermentation tank 30-1 or 30-2 and feed it through the pasteurization stage 400. By way of illustration, considering a fermentation tank capacity of 30 litres, approximately 25 litres of fermented liquid may be fed to the pasteurization stage 400 to produce nutrient solution, and approximately 5 litres of fermented liquid accordingly remain in the fermentation tank to ensure maintenance of a suitably stable microbial community for conducting subsequent fermentation cycles.

Figure 4 schematically shows that fermented liquid is cycled through the heat exchanger 45. One will accordingly understand that heat from the fermented liquid being subjected to pasteurization in the pasteurization stage 400 is partly recovered by the heat exchanger 45 in order to preheat the fermented liquid, and thereby improve efficiency. The pasteurization stage 400 could be configured in any adequate manner. So-called plate heat exchangers (PHE) may especially be contemplated.

Reference numeral 20 in Figure 4 designates an optional water tank used e.g. for supplying the desired amounts of water required for conducting liquid composting and fermentation in the fermentation tanks 30-1 , 30-2. Water tank 20 is likewise coupled to the pump P via an associated valve Vw. An adequate amount of water can be selectively drawn from the water tank 20 by the pump P and routed to feed the fermentation tank 30-1 or 30-2 via a recirculation valve Vc and a feed valve VFI-2 or VF2-2 provided at an input of each fermentation tank 30-1 , 30-2.

Reference numeral 50 in Figure 4 designates an optional rinsing device that can be used to rinse components of the organic waste processing system, including e.g. the fermentation tanks 30-1, 30-2 and/or components of the preprocessing stage.

Referring again to Figure 2, one will appreciate that, according to the invention, one achieves separation between the liquid composting and fermentation at step S300, on the one hand, and actual production of the nutrient solution at step S400 (as well as the relevant plant growing process), on the other hand. In effect, pasteurization at step S400 ensures that a separate chemical environment can be maintained and optimized for composting/fermentation purposes at step S300 and the subsequent plant growing that makes use of the resulting liquid fertilizer as nutrient solution. This further allows for a higher processing capacity in that the relevant fermentation tank(s) can be used as storage vessels to produce and supply nutrients only when necessary.

As a further step, adjustment of the nutrient solution may be performed subsequently to the pasteurization step S400. In particular, it is contemplated to measure the acidity (pH) of the nutrient solution and perform adjustments (if required) to ensure that the pH of the nutrient solution is maintained within selected limits, e.g. a pH of 5.5 to 6.5. Adjustment of the pH may especially be carried by a selective addition of a suitable acid to bring down the pH of the nutrient solution should it be too high. Citric acid is particularly preferred in that regard as it constitutes an ecologically sustainable solution.

A measurement of the acidity (pH) may likewise be performed during liquid composting and fermentation at step S300, and adjustments may similarly be carried out to maintain the pH at a desired level. More specifically, the pH of the fermented liquid could in particular be adjusted and maintained within a range of 6.5 to 8 (i.e. a pH higher than that of the nutrient solution). Should the pH of the nutrient solution be too low, acidity of the nutrient solution may be lowered by selectively producing fresh nutrient solution and adding it to the existing nutrient solution.

Measurements of conductivity of the nutrient solution could further be carried out in order to derive an indirect indication of the nutrient solution strength and concentration of mineral constituents. If the concentration is too high, water may be added to dilute the nutrient solution. Conversely, if the concentration is too low, fresh nutrient solution may be produced and added to increase concentration of mineral constituents.

Figure 5 is a schematic illustration of a modular hydroponic farming structure, designated globally by reference numeral 5000, for growing vegetables or fruits. This hydroponic farming structure comprises an organic waste processing system 1000 according to a preferred embodiment of the invention (as described in greater detail hereafter) that supplies a nutrient solution to multiple hydroponic planting receptacles 560. One or more nutrient solution tanks 510 are provided to suitably store the nutrient solution produced by the organic waste processing system 1000. Nutrient solution is fed to the relevant hydroponic planting receptacles 560 through an adequate distribution system integrated into the structure supporting the hydroponic planting receptacles 560. By way of preference, the hydroponic farming structure 5000 is designed to be modular, namely to allow any desired number of nutrient solution tanks 510 and hydroponic planting receptacles 560 to be installed.

Figure 5A is a schematic illustration of a modular unit 550 comprising one hydroponic planting receptacle 560 supported by an associated vertical support member 555 via a mounting element 550B. Reference sign 550A designates a feed port (here retractable) configured to supply nutrient solution to the hydroponic planting receptacle 560. A suitable circulation of nutrient solution is ensured by allowing the nutrient solution to flow out of the feed port 550A, to the hydroponic planting receptacle 560, and from the base of the hydroponic planting receptacle 560, through the mounting element 550B, back to the vertical support member 555. In effect, nutrient solution is fed from the top and allowed to flow by gravity through the hydroponic planting receptacle 560 as schematically illustrated by the white arrows in Figure 5A.

Multiple modular units 550 as shown in Figure 5A can be assembled in one or multiple vertical structures, as shown in Figure 5, by assembling multiple units 550 one on top of the other. To this end, as shown in Figure 5A, each vertical support member 555 is provided with a pair of mounting elements 555A configured to be insertable in corresponding pair of mounting points 555B provided at the top of each vertical support member 555. In this way, multiple modular units 550 can be mounted one on top of the other, in different orientations as shown in Figure 5. By way of illustration, Figure 5 shows a series of five vertical structures each consisting of an assembly often modular units 550 mounted with different orientations to create a suitable working space above each planting receptacle 560. Figure 5 further shows that the vertical structures are connected together at the top by means of horizontal frame structure 520/520A/525/525A.

Feeding of the nutrient solution from the nutrient solution tank 510 is ensured by a suitable distribution system (not shown) housed within the structural elements 520, 520A, 525, 525A, 555 of the farming structure, nutrient solution being fed from the top of each vertical structure to allow the nutrient solution to be distributed to and circulate through each of the hydroponic planting receptacles 560.

Each hydroponic planting receptacle 560 may advantageously be designed to be removable from the associated mounting element 550B (see e.g. Figure 5B showing the modular unit 550 of Figure 5A with the hydroponic planting receptacle 560 being omitted for the sake of illustration) to facilitate harvesting and sharing of living plants if desired. Reference sign 550b in Figure 5B designates a suitable quick-coupling connector that can be coupled to a corresponding connection port provided at the bottom of the hydroponic planting receptacle 560.

Any adequate hydroponic farming structure may be used in connection with the invention, and the illustrations of Figures 5 and 5A-B are therefore understood to be purely illustrative. The hydroponic farming structure could for instance be based on the hydroponic structure forming the subject-matter of European patent application No. 20212686.8 of December 9, 2020, titled “HYDROPONIC GROWING SYSTEM”, in the name of the present Applicant, the content of which is incorporated herein by reference.

A preferred embodiment of the organic waste processing system 1000 will now be described with reference to the illustrations of Figures 6A-B to 16-16A. It will be appreciated that such organic waste processing system is likewise designed and configured to carry out the preferred process depicted in the flowchart of Figure 2, inclusive drying and temporary storage of the dried preprocessed organic waste. The illustrations of Figures 6A-B to 16-16A in effect show a fully integrated solution suitably combining all relevant functionalities in a single system, moreover in a compact manner.

Figures 6A and 6B are perspective views respectively showing a front side and a rear side of the organic waste processing system 1000. The organic waste processing system 1000 generally takes the shape of a vertical structure comprising a feed location IN provided at the top of the structure where organic waste can be fed. Functional components of the organic waste processing system 1000 are housed within the structure that is closed on all sides by panels 1000A-1000E, namely an upper panel 1000A, front and rear panels 1000B, 1000D and a pair of side panels 1000C, 1000E. The feeding location IN, located behind the upper panel 1000A, is normally closed by a pivotable lid 1000L secured to the front panel 1000A, which lid 1000L can be pivoted to an open position, as shown in Figures 6A-B, giving access to a feeding chamber where the organic waste can be fed by the user. Visible in Figure 6A is a removable storage compartment (or temporary storage stage) 1400 as well as a ventilation fan 1330, the functions of which will be explained later. Visible in Figure 6B is part of a drying stage 1300 and associated exhaust filter 1350, here shown in a position removed from an associated filter socket 1325.

Figure 7 is an exploded perspective view of the organic waste processing system 1000 of Figures 6A-B, with panels 1000A-E removed from the internal frame structure supporting the various functional components of the organic waste processing system 1000. Such functional components include, from top to bottom, a preprocessing stage 1100/1200/1250 (shown in greater detail in Figures 8-12), a drying stage 1300 (shown in greater detail in Figures 13 and 13A-D), a temporary storage stage 1400 (shown in greater detail in Figures 14A-D) and a liquid fermentation stage 1500 including a pair of fermentation tanks 1510-1, 1510-2 (shown in greater detail in Figures 15A-B). A pasteurization stage 1600 (shown in greater detail in Figures 16 and 16A) is further located on the side next to the drying stage 1300 and temporary storage stage 1400, behind panel 1000E. Reference numeral 1550 in Figure 7 designates a pair of aeration pumps that are each coupled to an aeration device (see Figure 15C) located within each of the two fermentation tanks 1510-1 , 1510-2 to provide aeration of the fermented liquid, while reference sign P designates a pump used to selectively draw fermented liquid from one or the other of the two fermentation tanks 1510-1, 1510-2 and feed such fermented liquid to the pasteurization stage 1600 as already explained in connection with Figure 4.

As previously mentioned, no particular thermal insulation of the fermentation tanks 1510-1, 1510-2 is contemplated to ensure that fermentation can suitably take place at room temperature, while allowing heat that is inherently generated by the exothermic fermentation process to be rejected into the environment.

Not shown in Figures 6A-B and 7 are the relevant connectors used to couple the pasteurization stage 1600 to the one or more nutrient solution tanks 510 of the modular hydroponic farming structure 5000. In other embodiments, a nutrient solution tank could possibly be incorporated directly into the organic waste processing system.

The preprocessing stage 1100/1200/1250 will now be described with reference to the illustrations of Figures 8-12. Figure 8 is a perspective view of the preprocessing stage 1100/1200/1250 which advantageously combines, in the illustrated example, multiple functionalities. The preprocessing stage 1100/1200/1250 in essence consists of a combination of a compactor device 1100 designed to squeeze the organic waste, a shredder device 1200 designed to chop the organic waste into grinded organic waste components, and a collector device 1250 designed to remove excess moisture from the organic waste. More specifically, the compactor device 1100, shredder device 1200 and collector device 1250 are arranged in sequence to form a single preprocessing stage or apparatus combining all relevant preprocessing functionalities.

Figure 9 is an exploded partial perspective view showing relevant components of the compactor device 1100 (also visible in Figures 8 and 12), including a compactor chamber 1110, a compacting piston 110OP and a linear actuator 1100A and associated drive motor 1100M. The compactor chamber 1110 is configured and dimensioned to receive the compacting piston 11 OOP which is linearly driven by means of the linear actuator 1100A under the action of the drive motor 1100M. Compactor chamber 1110 is provided on its upper section with an opening 1110A that coincides with the position of the corresponding opening formed in the upper panel 1000A where the pivoting lid 1000L is located, upper panel 1000A and pivoting lid 1000L being also shown in Figure 9. One will thus appreciate that the cavity created inside the compactor chamber 1110, upon retraction of the compacting piston 11 OOP, coincides with the aforementioned feed location IN where organic waste is supplied. A further opening 1110B is formed on a frontal area of the compactor chamber 1110, the configuration and position of which coincide with the configuration and position of the downstream- located shredder device 1200 (as shown in Figures 8 and 12). Reference sign 1100a in Figures 8 and 9 designates a pair of longitudinal supporting brackets secured to either side of the compactor chamber 1110, while reference sign 1100b designates a rear bracket supporting the linear actuator 1100A and associated drive motor 1100M. In operation, organic waste fed inside the cavity of the compactor chamber 1110 is squeezed under the action of the compacting piston 11 OOP, namely at the location coinciding with opening 1110B, upstream of the shredder device 1200. Excess moisture is extracted from the organic waste as a result, which liquid is allowed to flow through the shredder device 1200 to be collected by the collector device 1250. One or more compacting operations could be undertaken in practice with a view to adequately squeeze the organic waste and extract as much excess moisture as possible. Following such compacting operation(s), the shredder device 1200 may be put into operation, the compacting piston 11 OOP being then used to push the compacted organic waste through the shredder device 1200.

Figure 10 is a perspective view of the shredder device 1200 which basically includes a shredder chamber 1210 with a shredder inlet 1210A configured and dimensioned to be coupled to the frontal opening 1110B of the compactor chamber 1110, which shredder chamber 1210 houses a pair of shredding rotors 1200B with mutually engaging shredder blades. The shredding rotors 1200B are mounted on associated driving shafts 1200A supported at both longitudinal ends of the shredder chamber 1210 and are driven into rotation in opposite directions under the action of an associate drive mechanism comprising a drive motor 1200M and gearing 1200G. Figure 10A is an exploded view of the shredder device 1200.

Operation of the shredder device 1200 is in essence similar to conventional twin- shaft shredder devices. In the present example, one will understand that, in operation, organic waste is pressed through the shredder chamber 1210 under the action of the compacting piston 11 OOP, causing the organic waste to be chopped into grinded organic waste components at the outlet of the shredder chamber 1210. Figures 11A-D show the collector device 1250 that is positioned downstream of the shredder device 1200 (as shown in Figures 8 and 12) to collect, both, the liquid recovered from the organic waste during compaction and the grinded organic waste components produced as a result of the shredding operation. More specifically, the collector device 1250 includes first and second collection chambers 1250a, 1250b that are separated by a particle mesh 1255. Furthermore, as shown in Figure 11 D, a pivotable flap 1256 (or like movable element) is positioned inside the first collection chamber 1250a in a lower portion thereof so as to selectively obstruct a lower section of the first collection chamber 1250a which communicates with a first outlet 1250A. The second collection chamber 1250b is positioned downstream of the first collection chamber 1250a, behind the particle mesh 1255, and communicates with a second outlet 1250B.

In a first configuration, as depicted in Figure 11 D, the flap 1256 is moved to obstruct the lower section of the first collection chamber 1250a to allow liquid that is recovered from the compacting operation to flow through the particle mesh 1255 to the second collection chamber 1250b. Liquid thus recovered and collected in the second collection chamber 1250b is advantageously fed directly to the liquid fermentation stage 1500 via an adequate tubing system (not shown) connected to the second outlet 1250B.

Conversely, in a second configuration, the flap 1256 is moved to a lower position, thus freeing the lower section of the first collection chamber 1250a and allowing the grinded organic waste components to fall by gravity through the first outlet 1250A to the subsequent stage, namely the drying stage 1300.

Figure 12 is a cross-sectional view of the preprocessing stage 1100/1200/1250 highlight the relevant paths of the liquid that is extracted from the organic waste as a result of the compacting operation carried out in the compactor device 1100 and of the grinded organic waste components that are produced as a resulting of the shredding operation carried out by the shredder device 1200. As already mentioned, the extracted liquid recovered at the second outlet 1250B is advantageously fed to the liquid fermentation stage 1500, while the grinded organic waste components are fed through the first outlet 1250A to the downstream-located drying stage 1300.

Figure 13 is a perspective view of the drying stage (or apparatus) 1300 that is positioned immediately after the aforementioned preprocessing stage 1100/1200/1250. In the illustrated example the drying stage 1300 in essence consists of a convective air dryer. More specifically, the grinded organic waste components coming from the preprocessing stage 1100/1200/1250 are fed inside a ventilated drying chamber 1310/1315/1320 where drying of the organic waste can be selectively carried out, if required. One will appreciate and understand that the drying stage 1300 is not necessarily active at all times and that the preprocessed organic waste may in effect be fed through the drying stage 1300 without carrying out any drying operation at all. In other words, while the preprocessed organic waste is systematically fed through the drying stage, drying of the preprocessed organic waste is only carried out if necessary, especially if the quantity of organic waste to be processed exceeds the relevant processing capacity of the liquid fermentation stage 1500.

Looking at Figure 13, one will understand that the preprocessed organic waste is fed inside the ventilated drying chamber 1310/1315/1320 through an inlet 1310A formed in an upper side 1310 of the drying chamber 1310/1315/1320. In effect, the first outlet 1250A of the aforementioned collector device 1250 is coupled directly to the upper side 1310 at the position coinciding with the inlet 1310A. Visible in Figure 13 is the exhaust filter 1350 positioned inside the associated filter socket 1325 that is formed alongside a portion of a peripheral wall 1320 of the drying chamber 1310/1315/1320. Positioned immediately below a lower side 1315 of the drying chamber 1310/1315/1320 is a dispensing mechanism 1380 the configuration and function of which will be described with reference to Figures 13B-D.

Figure 13A is a perspective view of the drying stage 1300 of Figure 13 showing the exhaust filter 1350 removed from the associated filter socket 1325. As depicted in Figure 6B, one will appreciate and understand that a corresponding opening is formed in the rear panel 1000D to allow direct access to the exhaust filter 1350, which can thus be removed without this necessitating removal of the rear panel 1000D as such. The exhaust filter 1350 may in particular include an active charcoal filter for adequately capturing and filtering undesired odours and smells, which may require periodic exchange, hence the facilitated access to the exhaust filter 1350.

Figures 13B and 13C are exploded perspective views of the drying stage 1300 revealing the inner structure thereof. As shown, the drying stage 1300 includes a pair of drying plates 1340, 1345 positioned one above the other and that are each coupled to an associated ultrasound transducer 1340US, resp. 1345US (visible in Figure 13C). As already mentioned, ultrasound is advantageously used to break down the organic waste on a microscopic level, leading to destruction of dehydration barriers, which facilitates water extraction from the organic waste and improves the drying speed. Each drying plate 1340, 1345 is provided with at least one opening 1340A, 1345A and is further equipped with a turning blade 1341 , 1346 to drive the preprocessed organic waste over the surface of each drying plate 1340, 1345 and, ultimately, through the opening 1340A, 1345A to proceed downwards until the preprocessed organic waste reaches the top surface of the lower side 1315 of the drying chamber 1310/1315/1320. Reference sign 1300M in Figures 13 and 13A-C designates a drive motor that is used to drive the turning blades 1341, 1346 into rotation via a common driving shaft 1300S (visible in Figure 13C only). Also visible in Figures 13B and 13C is the ventilation fan 1330 that is used to feed air inside the drying chamber 1310/1315/1320 through a corresponding aperture formed in the peripheral wall 1320. This ventilation fan 1330 is advantageously associated to a heating element 1335 to blow hot air inside the drying chamber 1310/1315/1320. As shown in Figure 13C, the lower side 1315 of the drying chamber 1310/1315/1320 is equipped with a turning blade 1316 that is likewise driven into rotation by the drive motor 1300M via the common driving shaft 1300S.

Referring additionally to Figure 13D, one may note that the lower side 1315 of the drying chamber 1310/1315/1320 is provided with three outlets, namely a pair of outlets 1315A and a third outlet 1315B. The pair of outlets 1315A communicates with the liquid fermentation stage 1300, via the dispenser mechanism 1380, while the third outlet 1315B communicates with the temporary storage stage 1400, likewise via the dispenser mechanism 1380. More specifically, the dispenser mechanism 1380 is designed to selectively feed the organic waste to either one of the liquid fermentation tanks 1510-1, 1510-2 (via one or the other of the outlets 1315A) or to the temporary storage stage 1400 (via the third outlet 1315B), depending on the operating status and need.

The dispensing mechanism 1380 is shown in exploded view in Figure 13D and comprises two sections, namely a first dispensing section cooperating with the pair of outlets 1315A and a second dispensing section cooperating with the third outlet 1315B. More specifically, the first dispensing section comprises a first rotatable shutter plate 1392 provided with one or more openings 1392A, 1392B, which shutter plate 1392 can be used to selective close one or both of the outlets 1315A or allow passage of (dried or undried) organic waste to the downstream -located fermentation stage 1500. Shutter plate 1392 is provided with a peripheral toothing that meshes with a drive pinion 1390G that can be driven into rotation by an associated drive motor 1390M. Similarly, the second dispensing section comprises a second rotatable shutter plate 1397 that is provided with an opening 1397A, which other shutter plate 1397 can likewise be used to selective close the associated outlet 1315B or allow passage of dried organic waste to the downstream-located temporary storage stage 1400. Shutter plate 1397 is also provided with a peripheral toothing that meshes with a drive pinion 1395G that can be driven into rotation by an associated drive motor 1395M. The shutter plates 1392, 1397 and associated drive pinion 1390G, 1395G are supported into corresponding sections 1390, 1395 of a supporting member 1385 that is secured to the lower side 1315 of the drying chamber 1310/1315/1320. Reference numerals 1391 and 1396 designate first and second cover members that are interposed between the shutter plates 1392, 1397 and associated drive pinion 1390G, 1395G, on the one hand, and the lower side 1315 of the drying chamber 1310/1315/1320, on the other hand. Corresponding apertures 1391 A and 1396A are formed in these cover members 1391, 1396 at positions coinciding with the positions of outlets 1315A and 1315B. As shown in Figure 31 D, the first section 1390 of the supporting member 1385 is provided with a corresponding pair of outlets 1390A, 1390B, facing outlets 1315A, while the second section 1395 of the supporting member 1385 is provided with an outlet 1395A facing outlet 1315B.

One will appreciate and understand that organic waste can selectively be allowed to be fed to either one of the downstream-located fermentation tanks 1510-1, 1510-2 by actuating the shutter plate 1392 to open the associated outlet 1390A or 1390B. Referring to Figure 15A, organic waste allowed to go through outlet 1390A or 1390B is fed to the associated fermentation tank 1510-1 or 1510-2 located immediately below via inlet 1510A. One will likewise appreciate and understand that, should it be required to temporarily stored dried organic waste that was subjected to a drying operation in the drying stage 1300, such dried organic waste can selectively be allowed to be fed to the downstream-located temporary storage stage 1400 by actuating the shutter plate 1397 to open the associated outlet 1395A. As shown in Figure 7, the second section 1395 in effect sits immediately above the temporary storage stage 1400.

Figures 14A and 14B are perspective views of the temporary storage stage 1400 that is located immediately below the drying stage 1300, namely underneath the second section 1395 of the supporting member 1385. It will be appreciated and understood that the temporary storage stage 1400 is designed and configured to temporarily store dried organic waste in the event that the amount of organic waste inputted in the system exceeds a nominal processing capacity. As already mentioned, such dried organic waste may be temporarily stored prior to subjecting it to liquid fermentation. Should the amount of dried organic waste exceed a temporary storage capacity, excess waste could potentially be removed from the temporary storage stage 1400 and still be used as additional long-term composting fertilizer for outdoor soil- grown plants. In that respect, the temporary storage stage 1400 advantageously includes a removable storage drawer 1410 configured to receive the dried preprocessed organic waste, which storage drawer 1410 can conveniently be removed from the organic waste processing system 1000 as schematically depicted in Figure 6A. More specifically, the removable storage drawer 1410 comprises a front face 1410A emerging through a corresponding opening provided in the front panel 1000A and a recess shaped to form a hand grip 1410B to allow the removable storage drawer 1410 to be pulled out. The internal cavity 1410C formed within the boundaries of the removable storage drawer 1410 is configured and dimensioned in such a way as to allow temporary storage of dried organic waste in an amount sufficient to cope with a certain level of excess organic waste and thus act as a buffer.

A pair of outlets 1400A, 1400B are formed at the bottom of the internal cavity 1410C of the storage drawer 1410 to provide a path to feed the dried organic waste to either one of the two fermentation tanks 1510-1, 1510-2. Each outlet 1400A, 1400B can be selectively closed or opened to allow passage of the dried organic waste using a shutter mechanism comprises a pair of individually-actuatable shutter elements 1450, 1455 visible in Figures 14B to 14D. The shutter elements 1450, 1455 are actuated by means of a drive motor 1450M positioned at a rear end of the drawer 1410, which drive motor 1450M is coupled to an actuating element 1450F shaped as a fork that can be translated to actuate one or the other shutter element 1450 or 1455 as illustrated in Figure 14D.

Advantageously, a pair of rotatable mixing blades 1430, 1435 are positioned at the bottom of the internal cavity 1410C to distribute the dried organic waste within the internal cavity 1410C and facilitate extraction thereof through the outlet 1400A or 1400B upon being opened. The mixing blades 1430, 1435 are selectively driven into rotation by means of a dedicated drive motor 1430M driving the mixing blades 1430, 1435 via a gearing 1430G. Reference sign 1430H in Figure 14C designates a gear housing within which the gearing 1430G is located.

One will appreciate and understand that dried organic waste can selectively be allowed to be fed to either one of the downstream-located fermentation tanks 1510-1, 1510-2 by actuating the relevant shutter element 1450, 1455 to open the associated outlet 1400A or 1400B. Referring to Figure 15A, organic waste allowed to go through outlet 1400A or 1400B is fed to the associated fermentation tank 1510-1 or 1510-2 located immediately below via inlet 1510B.

A pivotable handle 1420 is further provided at an upper portion of the storage drawer 1410 to facilitate handling of the storage drawer 1410 upon being removed from the organic waste processing system 1000. This handle 1420 is pivotable between a horizontal position, on top of the storage drawer 1410, when not in use (as shown in Figure 14A) and a vertical position to carry the storage drawer 1410.

Figures 15A and 15B are a perspective view and a side view, respectively, of the first fermentation tank 1510-1. Figure 15C is a cross-sectional view of the first fermentation tank 1510-1 as taken along sectional plane B-B represented in Figure 15B. It will be understood that the second fermentation tank 1510-2 exhibits a mirrored configuration with similar features. More specifically, the fermentation tank 1510-1 is configured as a vessel having a body 1515 of suitable capacity to perform liquid composting and fermentation of the organic waste. In the illustrated example, each fermentation tank 1510-1, 1510-2 has a capacity of the order of 30 litres. Three inlets are provided in the upper part of each fermentation tank 1510-1, 1510-2, as shown in Figure 15A, namely a first inlet 1510A designed to receive organic waste coming from the drying stage 1300, a second inlet 1510B designed to receive dried organic waste coming from the temporary storage stage 1400, and a third inlet 1510C designed to receive liquid coming from the collector device 1250C.

Figures 15A to 15C show that an opening 1515a is formed within the peripheral wall of the body 1515 to provide access to the inner side of each fermentation tank 1510-1, 1510-2. Such opening 1515a is normally closed by a removable panel (not shown). A particle filter 1520 is advantageously provided inside the body 1515 to hold solid particles within each fermentation tank 1510-1 , 1510-2 and allow extraction of the fermented liquid via an outlet 1515A provided at the bottom of body 1515. Reference sign 1515B in Figures 15A to 15C designates a drainage outlet designed to allow manual drainage of the fermentation tank in case of need. Reference numeral 1530 in Figure 15C designates an aeration device that is operatively coupled to the aforementioned aeration pump 1550.

Figures 16 and 16A are illustrative of an embodiment of a plate heat exchanger (PFIE) usable as pasteurization stage 1600. In the illustrated example, the pasteurization stage 1600 consists of a multi-layered plate structure comprising two heating plates 1600H designed to heat the fermented liquid which is forced to flow within dedicated liquid channels formed in associated liquid channel plates 1610 affixed to each heating plate 1600H. The heated liquid is further forced to flow through a number of heat exchanger plate structures each comprising a heat exchanger plate 1600C sandwiched between first and second liquid channel plates 1615, 1620 in order to preheat the incoming (i.e. cold) fermented liquid. More specifically, the incoming, cold liquid is forced to flow through dedicated liquid channels formed in each liquid channel plate 1620, while the hot liquid is forced to flow through dedicated liquid channels formed in each liquid channel plate 1615, causing a transfer of heat. Cold liquid is first fed from the bottom of the multi-layered plate structure and flows to the top of the structure, where the heating plates 1600H are located, before being fed back to the bottom of the structure via a liquid duct 1650.

Various modifications and/or improvements may be made to the above-described embodiments without departing from the scope of the invention as defined by the appended claims.

For instance, numerous adaptations may be made to the organic waste processing system discussed with reference to Figures 6A-B to 16, 16A while retaining the basic functionalities that are contemplated in the context of the present invention. In particular, while the removable storage drawer constitutes a valuable and particularly advantageous addition, any other storage solution could be contemplated. It will also be appreciated and understood that the drying stage (and associated temporary storage stage) could be omitted entirely.