Non-plastic biofilm support element for biological wastewater treatment facility

Abstract

The invention relates to a biofilm support element for a biological wastewater treatment facility, consisting of a lignocellulosic plant compound having recesses and / or grooves or a part of such a compound, which compound or part of such a compound has been pre-washed, dried and treated, and the water-proof effect is achieved, and the density is enough to maintain suspension and movement in water. The invention also relates to a process for treating a lignocellulosic plant compound having recesses and / or grooves or a portion of such a compound in order to obtain a predefined support element, comprising the following steps: a cleaning step; a heat treatment step resulting in a weight loss of 10% to 30%; a step of impregnation with at least one water repellent compound; and a drying step, the heat treatment step being able to be carried out before or simultaneously with the waterproofing step.

Description

Technical Field

[0001] This invention relates to the field of biological treatment facilities for urban and industrial wastewater.

[0002] More specifically, the present invention relates to biofilm support elements for such facilities, wherein the biomass present on these support elements enables the removal of contaminants from the water passing through them. The invention also relates to a processing method for obtaining such support elements. Background Technology

[0003] The biofilm support elements used in such facilities (hereinafter referred to as "support elements") are typically in the form of plastic elements ranging in size from a few millimeters to a few centimeters. These elements have a high specific surface area, most of which defines a cavity or protrusion in which biomass can grow while being protected, particularly from friction between elements. Such support elements are commercially available, particularly in media called AnoxKaldnes® K5. These support elements advantageously have a relative density of slightly less than 1, allowing them to be carried by the movement of water in the reactor. When using such a water treatment facility, these support elements remain suspended and in motion within the reactor containing them.

[0004] Wastewater treatment facilities incorporating such movable support elements can increase the amount of biomass per unit volume without increasing reactor size, and thus advantageously enable the treatment of larger volumes of wastewater and / or contaminants at a constant volume compared to activated sludge facilities.

[0005] The plastic materials used to manufacture these support elements allow them to have a wide range of sizes and shapes. Furthermore, they are inexpensive, thus enabling the production of these support elements at low cost.

[0006] Using such plastic support elements also offers the following advantages: - Rapid bacterial growth on the support elements, even at low temperatures; - The biofilm supporting the elements exhibits high tolerance to changes in the pollution load to be treated and to the toxic substances produced by the biofilm. - Higher pollutant removal yield than existing activated sludge processes; - Adjustable filling rate of the support elements in the reactor, depending on the pollution load to be treated in the reactor; - A more stable contaminant removal process due to the reliable attachment of the biofilm to the support element.

[0007] However, in an era of growing environmental problems, the use of these plastic support elements has come under increasing criticism. Numerous incidents have occurred in which these elements have entered the natural environment (cargo grounding, leaks from wastewater treatment facilities), leading to pollution of beaches and aquatic environments. These plastic support elements also have the drawback of degrading over time, releasing very small particles (microplastics), which are now considered potentially toxic to humans and animals, particularly marine animals.

[0008] Therefore, these plastic support elements need to be replaced with support elements made of other materials that are more respectful of people and nature. It should be understood that these support elements must: - Composed of materials that allow for the growth of biomass; - It has a structured surface for sustainable adhesion over time; - It has a density suitable for being set as motion in the processing reactor, and this density must be substantially constant over time; - It is resistant over time, especially to wear caused by friction with other support elements, the movement of the water to be treated, and the movement of bubbles that may be used to oxidize biomass and maintain the suspension and movement of the support elements in the reactor under treatment.

[0009] In this context, biological treatment processes for wastewater using support elements made of non-plastic materials, primarily ceramic, are known in the prior art, although most of these processes use these support elements in fixed beds.

[0010] Ceramic supports are advantageously colonized due to their protected surfaces and can effectively handle carbon and nitrogen. However, manufacturing these ceramic supports is energy-intensive and highly complex for large-scale production. They can be produced using additive manufacturing techniques with 3D printers, but this type of process remains very expensive and relatively complex to implement.

[0011] On the other hand, such support elements made of non-plastic materials do not always possess the physical properties necessary to make them economically viable for a period of time in wastewater treatment facilities. Therefore, they may not be resistant to compression, breakage, and aging.

[0012] Finally, they do not necessarily have a density compatible with optimal motion within the treatment reactor. In particular, the support elements made of non-plastic materials that have been used to date, once loaded into the treatment reactor and immersed in water, do not have a suitable density that allows them to properly maintain suspension and motion.

[0013] Therefore, a primary objective of this invention is to provide a biomass support element not made of plastic materials, which can accommodate biofilms and be used sustainably in wastewater treatment facilities, and particularly for moving bed reactors, also known as stirred tank reactors. Thus, one objective of this invention is to provide an environmentally friendly alternative to existing plastic support elements conventionally used in this type of facility.

[0014] Another object of the present invention is to provide such biomass support elements that can be optimally maintained in suspension and motion in a treatment reactor, typically of the moving bed reactor type, wherein the biomass support elements are movable relative to each other and fluidization can be performed using a fluid such as water or air, for example, fed into the reactor at a controlled rate.

[0015] Another object of the present invention is to provide a support element that is easy and inexpensive to manufacture.

[0016] Another object of the present invention is to provide a support element that has a significantly lower manufacturing carbon footprint than plastic elements used in the prior art. Summary of the Invention

[0017] These objectives are achieved, in whole or in part, by the present invention. One objective of the present invention is a biofilm support element for a biological wastewater treatment facility, characterized in that it comprises a lignocellulosic plant compound having asperities and / or grooves, or a portion thereof, said compound or a portion thereof having been pre-cleaned and treated to have a density suitable for maintaining suspension and movement in the reactor of said facility.

[0018] More specifically, after numerous tests, the inventors were able to confirm that these lignocellulosic plant compounds, or portions of compounds with irregularities and / or grooves, when washed and treated to have a density suitable for maintaining suspension and movement in a moving bed reactor, can sustainably accommodate biofilms due to their surfaces being protected from friction with other compounds of the same type, and can be used in biological wastewater treatment facilities employing biofilm support elements, replacing prior art plastic support elements. Such lignocellulosic plant compounds according to the invention have a density of 400 m³. 2 / m 3 With 1500 m 2 / m 3 The protective surface area between them.

[0019] Therefore, the use of non-plastic support elements according to the invention makes it possible to reduce the environmental impact of wastewater treatment facilities that use them.

[0020] According to the present invention, these compounds and / or compound portions are cleaned, dried and waterproofed to make them suitable for use as biomass support elements in wastewater treatment facilities, particularly moving bed reactors, which effectively remove contaminants from these waters in a satisfactory and sustainable manner.

[0021] Lignocellulose compounds are essentially composed of cellulose, hemicellulose, and lignin. The treatment of lignocellulose compounds or compound fractions according to the invention enables the removal of most of the hemicellulose initially present on the surface of these compounds and / or compound fractions. Therefore, by optimizing the energy required to do so through aeration or mechanical agitation, their densities are altered so that they can be suspended and move within the biological water treatment reactor. In practice, this treatment results in the relative density of these compounds or compound fractions reaching a value slightly below that of water after treatment and before they are inserted into the reactor, practically between 0.90 and 0.99, preferably between 0.95 and 0.99. The biomass support elements must not float on the surface of the water in the reactor, especially in the case of stirred reactors, nor must they be so heavy that they require excessive energy to suspend or initiate movement.

[0022] These naturally derived, non-plastic support elements can begin to move in the reactor, either in the presence of water to be treated alone or in the presence of a mixture of water to be treated and sludge.

[0023] According to a preferred embodiment, the process includes heat treatment that causes a mass loss of 10% to 30%, preferably at least 20%, of the compound or a portion thereof.

[0024] Therefore, according to one embodiment, the compound and / or compound portion after heat treatment exhibits a mass loss of 10 to 30%, preferably at least 20%, compared to the compound and / or compound portion before heat treatment.

[0025] This heat treatment ensures the removal of all hemicellulose, and thus reduces the density of the compound and / or compound fraction. Since hemicellulose represents the main hydrophilic component of the compound or compound fraction, its removal by the aforementioned heat treatment also allows the compound and / or compound fraction to be made less hydrophilic, and therefore this reduced density is more sustainably maintained after soaking in the reactor of a biological wastewater treatment facility. Therefore, preferably, after soaking in water for 5 days, the compound or compound fraction has a relative density between 0.90 and 1.1. Preferably, after soaking in water for 15 days, preferably 30 days, the compound or compound fraction has a relative density between 0.90 and 1.11.

[0026] Furthermore, according to one embodiment, the compound or compound portion is impregnated with a waterproof compound, for example, by a mixture of natural dried oils, such as Chinese sesame oil or linseed oil and silica. This impregnation enables the compound or compound portion to be waterproof and thus retains the desired density even more persistently after immersion in the reactor of a biological wastewater treatment facility.

[0027] According to a preferred embodiment, the impregnated compound or compound portion, i.e., after it has been impregnated, is dried.

[0028] According to one embodiment, the compound or a portion thereof is a fruit pit or part of a fruit pit, preferably derived from the fruit of a plant selected from walnut trees, almond trees, peach trees, olive trees, and cherry trees.

[0029] In the context of this invention, the term "walnut" refers to trees of the genus *Juglans*, particularly species of the genus *Juglans* that are commonly known as walnuts. However, other species of the genus *Juglans* whose fruits have similar characteristics to those of species of the genus *Juglans*, such as species of the genus *Juglans* var. *nuli*, may also be used.

[0030] By its usual definition, the term "pit" here refers to the hard, central part of a fruit. In botany, this pit includes the endocarp and the seed protected by it.

[0031] For the purposes of this invention, preferably, a portion of the nucleus represents a nuclear lobe.

[0032] In botany, the term "valve" refers to the two parts of the shell that make up the kernel of certain fruits. A walnut consists of a shell formed by two valves, which contains a seed called the kernel.

[0033] Since these natural elements are food waste, this invention enables them to be recycled.

[0034] These nuclei and / or nuclei have large, protected surface areas, allowing for optimal development of bacterial biofilms capable of removing contaminants from the water to be treated. Their irregular surfaces, with their bumps and / or grooves, enable the formed biofilms to grow under protection.

[0035] Such a core and / or core portion also possesses stiffness that limits its loss in the reactor.

[0036] These nuclei and / or nuclear parts are also inert relative to the environment and do not release toxic compounds.

[0037] Making these nuclei and / or nuclear parts waterproof also prevents them from being consumed by biomass.

[0038] The preferred kernels used are peach pits, and the kernel portion used is a peach hemi-kernel. The advantage of these kernels and hemi-kernels is that they have a particularly wrinkled surface, resulting in a high specific surface area, making them ideal for containing large amounts of biomass.

[0039] In one alternative, the core is a walnut shell.

[0040] According to another alternative, the kernel is the almond kernel.

[0041] Almond kernels have the advantage of being particularly hard, and therefore particularly resistant to friction, which is an advantage within the scope of this invention.

[0042] In another alternative, the core is an olive pit or a cherry pit.

[0043] In order for these olive or cherry pits to receive and protect the biofilm during the processing, it is preferable to break them into pieces.

[0044] Within the scope of this invention, it should be understood that any fruit pit or part of a fruit pit having properties similar to those described above can be used in this invention. Therefore, for example, apricot pits can also be used, but these are preferably used in block form, such as blocks of olive or cherry pits.

[0045] The present invention also relates to a process for treating a lignocellulosic plant compound having irregularities and / or grooves, or a portion thereof, to obtain a support element as defined above, characterized in that it comprises the following steps: - Cleaning steps, - A heat treatment step to obtain a relative density suitable for maintaining suspension and motion in the reactor, preferably between 0.9 and 0.99, for example between 0.95 and 0.99.

[0046] Preferably, the heat treatment step results in a weight loss of 10-30% for the compound or the compound fraction. This weight loss ensures that all hemicellulose has been removed, so that the compound or compound fraction firstly has the desired density, and secondly, is as hydrophilic as possible to maintain the desired density for as long as possible.

[0047] Preferably, the heat treatment step is performed at a temperature between 100°C and 350°C, more preferably between 150°C and 280°C, for 10 minutes to 24 hours, and more preferably between 30 minutes and 120 minutes. This heat treatment step can remove hemicellulose to reduce the density of the compound or compound moiety. This removal of hemicellulose also reduces the hydrophilicity of the compound or compound moiety, allowing it to sustainably maintain its density after immersion in the reactor. Hemicellulose forms the main hydrophilic component of the compound or compound moiety.

[0048] According to one embodiment, the process further includes a step of impregnation with at least one waterproof compound.

[0049] According to various embodiments, the heat treatment step may be performed before or simultaneously with the impregnation step.

[0050] The processing method according to the invention is easy to implement and requires no particularly specific equipment. It also has the advantage that the order of the heat treatment and impregnation steps can be changed. Furthermore, an initial cleaning step can improve the quality of the heat treatment and impregnation.

[0051] Preferably, the at least one waterproofing compound comprises a natural dried oil.

[0052] Because this oil is natural, it also has a positive impact on the environment.

[0053] Natural dried oils can be specifically selected from Chinese wood oil and linseed oil.

[0054] According to one alternative, the at least one waterproofing compound comprises natural dried oils and organic and / or inorganic additives.

[0055] These additives can, for example, make the plant support element more resistant and hydrophobic by impregnating most of its fibers. They can also be used to increase the waterproof lifespan of the support element. In this case, additives that are less biodegradable than waterproofing compounds are used.

[0056] Examples of such additives are ground glass powder, alginate, kaolin, rosin, chitosan, or natural salt.

[0057] Advantageously, the impregnation step includes: - The first sub-step involves placing the support element under a vacuum for a period of time between 15 minutes and 60 minutes, preferably at a pressure between 0.3 bar and 1.5 bar, preferably between 0.6 bar and 1 bar. - The second sub-step involves contacting the support element with the at least one waterproof compound at a pressure between 1.7 bar and 20 bar, preferably between 2 bar and 10 bar, for a period of time between 10 minutes and 20 hours, preferably between 30 minutes and 12 hours, and at a temperature between 20°C and 200°C, preferably between 40°C and 120°C.

[0058] According to one embodiment, the process further includes a drying step. Advantageously, the drying step is performed at a temperature between 20°C and 200°C, preferably between 50°C and 100°C, for a period of 0.5 days to 20 days, preferably between 1 day and 10 days. Attached Figure Description

[0059] An embodiment of the present invention will now be described with reference to the accompanying drawings, wherein: [ Figure 1 ]: Figure 1 Two views of a peach half-pit are shown before and after it has been fully processed by the process according to the invention. [ Figure 2 ]: Figure 2 This schematically illustrates an experimental reactor representing a conventional reactor used in biological wastewater treatment facilities, which utilizes support elements to maintain suspension and motion, such as... Figure 1 Those shown; [ Figure 3 ]: Figure 3 The illustration shows that Figure 2 The diagram shows the daily COD load (in kg oxygen / m³·day) to be treated and removed in the reactor (representing soluble chemical oxygen demand of carbon content) as a function of time (in days). [ Figure 4 ]: Figure 4 Two binocular magnifying glass views of the support element are shown, illustrating the effect according to... Figure 2 The outer and inner surfaces of the reactor described after 22 days. Detailed Implementation

[0060] According to one embodiment of the invention, a non-plastic support element composed of lignocellulosic plant compounds having concave and convex features and / or grooves, used in a stirred reactor and processed according to the invention's process, comprises peach hemikers.

[0061] The use of peach kernels is particularly advantageous for the initial compounds of these elements. More specifically, peach kernels have a high lignin content, exceeding 30% of their total compounds. The presence of lignin in the nucleus cell wall endows it with rigidity, impermeability, and resistance to microbial invasion and oxidative stress. Lignin consists of a multimodal network of heteropolymers of phenyl-propane units derived from the oxidative polymerization of p-coumarol, coniferyl alcohol, and sinapyl alcohol. It is generally considered a “glue” that binds the various components of the lignocellulose matrix of plant cell walls, composed of lignin, hemicellulose, and cellulose, and is insoluble in water.

[0062] Because lignin is adjacent to and associated with cellulose microfibers, it is generally recognized as a major barrier to the enzymatic hydrolysis of lignocellulose biomass. Therefore, the rigid structure of the peach pit shell allows for good bacterial attachment for biofilm development.

[0063] The treatment performed on these peach pits according to the invention also reduces the mass of these shells, and thus their density, and makes them hydrophobic to achieve optimal fluidization in the moving bed reactor in which they will be loaded. This treatment also improves their resistance to various forms of friction and impact (e.g., from bubbles, other pits, or reactor walls) as well as water and biological attack.

[0064] Process for handling peach pits

[0065] According to the embodiments described herein, peach half-pits have been processed using the processing technology according to the invention.

[0066] Therefore, peach pits from the agri-food industry are collected and cleaned. The two halves of these pits are mechanically separated and the seeds removed. The halves are then dried in the open air or in a desiccator at a temperature between 30°C and 100°C.

[0067] Subsequently, these cleaned and dried heminuclei undergo a heat treatment process at temperatures between 150°C and 280°C to remove the hemicellulose present in the shell.

[0068] Subsequently, these hemicellulose-free hemikers undergo a waterproofing process, which initially involves placing the hemikers within a shell and maintaining a pressure between 600 and 1000 millibars for a period of 15 to 60 minutes without any waterproofing compound. Next, naturally dried oils (corresponding to Chinese oil or linseed oil) and powdered inorganic additives (corresponding to glass powder) are added to the shell. This additive impregnates most of the fibers of the peach pit from the outer surface to the pit, making them more resistant and hydrophobic. The pressure in the chamber is then increased to 2 to 10 bar for a period of 30 to 12 hours at a temperature between 40°C and 120°C.

[0069] The waterproofed peach pits are then dehydrated by air-drying at a temperature between 50 and 100°C for 1 to 10 days. In all cases, the temperature used for this final drying is lower than the temperature range used for the heat treatment of the pits, so as not to alter the impregnation of the waterproofing compound in the shell.

[0070] Support elements obtained through processing technology

[0071] Figure 1 Two views of a peach pit are shown.

[0072] exist Figure 1 On the left side, the peach half-pit, which has been washed and dried but not yet heat-treated or waterproofed, corresponds to the peach half-pit from a fruit normally consumed. It has a matte brown color and a porous, slightly rough surface.

[0073] exist Figure 1On the right-hand side, it can be seen that the half-kernel that has undergone the heat treatment and waterproofing steps according to the invention has a different appearance from the untreated half-kernel. It is gray / black, slightly glossy, and its surface is less porous than that of the untreated half-kernel. Therefore, the peach half-kernel treated in this way is more hydrophobic than the untreated half-kernel.

[0074] The two views in the figure also clearly show the irregular surface of this core, which has hollow sections and grooves, allowing for the formation of biofilms to protect it.

[0075] Facilities containing layers of support elements

[0076] Figure 2 An example of a facility 1 for biological treatment of wastewater is shown, comprising an 8-liter experimental reactor 10 with an inlet pipe 11 at the bottom for water to be treated and an outlet pipe 12 at the top for treated water. The reactor 10 houses support elements 14 obtained according to the process of the invention, which are made of peach hemikers as described above. Finally, the facility also includes an air injection manifold 15 disposed at the bottom of the reactor 10 for suspending and initiating movement of the support elements and for aerating the bioreactor.

[0077] Results of using the support element according to the invention in a moving bed reactor

[0078] Load the peach pit processed according to the present invention into Figure 2 In the reactor, water to be treated is then supplied. The support elements are kept in motion and suspended by continuous air injection.

[0079] COD measurements were performed on the wastewater to be treated and the treated water to calculate the daily COD load to be treated in the reactor and the daily COD load eliminated by the treatment (in kilograms of oxygen per cubic meter per day).

[0080] The reactor volume was filled to 25% using support elements, and these elements were initiated into motion and suspension using continuous aeration. The COD of the water entering and leaving the reactor was measured over 101 days.

[0081] Figure 3 The daily COD load entering the reactor (triangle) and the daily COD load removed from the reactor (circle) (in kg oxygen / m³·day) are shown as a function of time (in days).

[0082] Therefore, in this experiment, the soluble COD load (an indicator of carbon pollutants) removed from the reactor on day 30 could be measured as 0.95 kg Oxygen / m³·day. At the end of the experiment, on day 91, the maximum COD load removed was 2 kg Oxygen / m³·day.

[0083] These results demonstrate that using peach hemikers as a biofilm support element in a moving bed reactor can effectively remove organic pollutants from wastewater. The results also indicate that the surface of the support element made from peach hemikers used in this experiment was rapidly colonized by biomass. Visual observation of the treated peach hemikers was performed on day 22. Therefore, the treated peach hemikers could be observed on their outer surface (…). Figure 4 (left side) and its hollow inner surface ( Figure 4 Significant bacterial colonization is shown on the right-hand side (of the pit). This colonization enables the formation of a homogeneous heterotrophic biofilm over most of the heminucleus. It is the natural structure of the peach pit that makes this optimal bacterial attachment possible. The bacteria are able to grow primarily in the protected region of the heminucleus to protect themselves from the shear forces in the reactor.

[0084] Examples of processes according to the invention and results of using support elements according to the invention in a moving bed reactor.

[0085] In a preferred example, the support is formed from a treated peach pit. The treatment of the peach pit involves three steps.

[0086] The first step involves heat treatment to remove hemicellulose. This heat treatment allows for a 20% loss in mass, ensuring that at least most of the hemicellulose has been removed.

[0087] The second step involves soaking the peach pits obtained from heat treatment.

[0088] Finally, the third step involves drying the soaked peach pits.

[0089] The heat treatment was performed at 250°C for 2 hours to remove hemicellulose from the peach pits. The 2-hour duration was advantageous because most of the mass loss occurred during the first two hours of the heat treatment. Tests have shown a mass loss of 24% during this heat treatment.

[0090] The applicant has observed that untreated peach hemikers have an average relative density of 1.2 after soaking in water for 5 days. By comparison, heat-treated peach hemikers, after heat treatment to remove hemicellulose, have an initial average relative density of 0.97 and maintain a lower density than untreated peach hemikers after 5 days of soaking.

[0091] However, the applicant has observed that after soaking in water for 14 days, the relative density of heat-treated peach half-pits increased from 0.97 to 1.11. Therefore, in addition to heat treatment, the process according to the invention preferably includes impregnating the peach half-pits with a natural dried oil (e.g., Chinese pine oil or a mixture of linseed oil and silica).

[0092] This impregnation process involves first placing pre-heat-treated peach pits under vacuum at 1 bar for 30 minutes. An impregnation mixture heated to 80°C is then added to the peach pits under vacuum. The peach pits and impregnation mixture are subsequently pressurized at 8 bar for 1 hour and 45 minutes.

[0093] Afterward, the peach pits treated in this way were recovered after the chamber containing the peach pits and the impregnation mixture under pressure was evacuated. These peach pits were then dried at 70°C for 7 days.

[0094] This process according to the invention enables the density of peach hemikarns to be maintained over time, which allows them to be used in moving bed reactors in biological water treatment facilities. Table 1 below summarizes the experimental results obtained during the testing of the relative density of peach hemikarns.

[0095]

[0096] Table 1: Summary of the average relative density of peach hemikers

[0097] Peach half-kernels processed in this way can, for example, be used in a moving bed reactor (MBBR) with aeration at 5 NL / min to maintain the fluidization of the peach half-kernels over a long period of time.

[0098] Laboratory tests performed on the heminuclei treated using the above-described process have demonstrated their fluidization stability and their ability to colonize with biofilms. The tests were conducted in a semi-automated experimental facility, which was supplied with actual effluent in alternating anaerobic (120 min) and aerobic (100 min, 5 NL / min) cycles, followed by discharge (20 min). After 166 days of testing, the peach heminuclei reached an 80% colonization level. This colonization was considered significant and indicates good microbial attachment to the support. Colonization occurred on both the concave and convex sides of the peach heminuclei. Therefore, the treatment according to the invention does not inhibit biofilm formation, and the treated support retains its shape and relative density (<1.1) over time, thus maintaining fluidization over time due to the treatment.

Claims

1. A biofilm support element for a biological wastewater treatment facility, characterized in that, It consists of a lignocellulose plant compound having ridges and / or grooves, or a portion thereof, which has been pre-cleaned and treated to have a density capable of suspending and moving in the reactor of the facility.

2. The support element according to claim 1, characterized in that, The compound or a portion thereof is impregnated with a waterproof compound.

3. The support element according to claim 2, characterized in that, The compound or the impregnated portion of the compound is dried.

4. The support element according to any one of claims 1 to 3, characterized in that, The compound or a portion thereof is a fruit pit or part of a fruit pit, preferably a fruit selected from the group consisting of walnut, almond, peach, olive and cherry trees.

5. The support element according to claim 4, characterized in that, The kernel is a peach kernel and the kernel portion is a peach half-kernel.

6. The support element according to claim 4, characterized in that, The kernel is a walnut shell segment.

7. The support element according to claim 4, characterized in that, The kernel is an almond kernel.

8. The support element according to claim 4, characterized in that, The core is an olive pit or a cherry pit.

9. A process for treating a lignocellulosic plant compound having irregularities and / or grooves, or a portion thereof, to obtain a support element according to any one of claims 1 to 8, characterized in that, It includes the following steps: - Cleaning steps, - A heat treatment step to obtain a suitable density for maintaining suspension and motion in the reactor.

10. The processing method according to claim 9, characterized in that, The heat treatment step is performed at a temperature between 100°C and 350°C, preferably between 150°C and 280°C, for a period of 10 minutes to 24 hours, preferably between 30 minutes and 120 minutes.

11. The processing method according to claim 9 or 10, characterized in that, It includes: - The step of impregnation with at least one waterproofing compound. The heat treatment step can be performed before or simultaneously with the waterproofing step.

12. The processing method according to claim 11, characterized in that, The at least one waterproofing compound contains natural dried oils.

13. The processing method according to claim 11 or 12, characterized in that, The impregnation step includes: - The first sub-step involves placing the support element under a vacuum at a pressure between 0.3 bar and 1.5 bar, preferably between 0.6 bar and 1 bar, for a period of time between 10 minutes and 120 minutes, preferably between 15 minutes and 60 minutes. - The second sub-step involves contacting the support element with the at least one waterproofing compound at a pressure between 1.7 bar and 20 bar, preferably between 2 bar and 10 bar, for a period of time between 10 minutes and 20 hours, preferably between 30 minutes and 12 hours, and at a temperature between 20°C and 200°C, preferably between 40°C and 120°C.

14. The processing method according to any one of claims 11 or 13, characterized in that, It includes a drying step, which is carried out at a temperature between 20°C and 200°C, preferably between 50°C and 100°C, for a period of 0.5 days to 20 days, preferably between 1 day and 10 days.

15. The processing method according to any one of claims 9 to 14, characterized in that, The heat treatment step results in a weight loss of 10% to 30% of the compound or the portion thereof.

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