Patent Description:
Biofilms are heterogeneous and complex structures of microorganisms, typically adhered on a surface and presenting sophisticated singular and collective behaviours.

The problems related to biofilms on industrial surfaces and processes are significant. For instance, the development of biofilms in drinking water distribution systems (DWDS) can cause pipe degradation, changes in the water organoleptic properties, but the main problem is related to the public health. Biofilms are the main responsible for the microbial presence in drinking water and can be reservoirs for pathogens.

In the food industry, biofilms are recognized as a source of recalcitrant contaminations, causing significant equipment damage, energy loss, food spoilage and are potential sources of public health problems due to outbreaks of foodborne pathogens.

Therefore, the understanding of the mechanisms underlying biofilm formation and its behaviour are of utmost importance in order to create effective control strategies.

Accordingly, there has been a great deal of research to better understand the mechanisms that promote biofilm development and to identify efficient control strategies. However, effective strategies for biofilm inactivation, removal from surfaces and regrowth prevention are not clearly identified. This is in part due to the absence of standardized assays for biofilm formation and control, particularly for industrial biofilms.

Various types of reactors are available to study biofilm formation and their control, as described in <NPL>. Several devices, for example the biofilm annular reactor, the concentric cylinders reactor, the flow cell reactor, the Propella™ reactor, the rotating cylinder reactor, and the CDC biofilm reactor, were developed to study biofilms autonomously from a DWDS or other industrial facilities where biofilm formation may be critical. These devices allow the test of different conditions trying to mimic industrial environments or DWDS and they can be fed with tap water, enriched water or appropriate medium. In fact, these devices may be used as DWDS models to achieve a diversity of goals. However, they were used mostly in laboratorial experiments and have some disadvantages, which are detailed below.

The biofilm annular reactor, the CCR reactor, the flow cell reactor, the Propella™ reactor, the RCR reactor and the CDC biofilm reactor have some common limiting aspects and disadvantages, related to the geometrical configuration of said reactors that can change the flow patterns, leading to a non-ideal mixing and a non-uniform biofilm formation. Moreover, it is not feasible to apply different chemical treatments simultaneously in these reactors, under controlled hydrodynamic conditions. It should be also noted that the biofilm annular reactor, the flow cell reactor, the Propella™ reactor and the CDC biofilm reactor use flat coupons lacking sufficient sampling surface area. As specific disadvantages of the CCR reactor, it is possible to mention the limited number of materials that can be tested - because only one surface material can be tested per experiment; the difficult sampling process; and the impossibility of performing replicates in the same experiment. On the other hand, in the Propella™ reactor, the biofilm development is difficult to follow, due to the non-transparent materials of the reactor. In the RCR reactor, the main disadvantages are the low number of sampling cylinders, only up to three, and a high working volume (<NUM>). Additionally, mechanical treatment is difficult to apply in the CDC biofilm reactor, because it is difficult to determine accurately the shear stress applied.

Other laboratorial devices, such as the microtiter plates, Calgary biofilm reactor, the drip flow biofilm reactor and the rotating disk reactor were developed to allow the study of biofilm formation and control under specific conditions, in order to fill the gap on the limitations of previously described reactors. However, these reactors were developed to study medical biofilms as analyzed by <NPL>. Their limitations to test industrial biofilms are significant as detailed below.

Specifically, the disadvantages of microtiter plates and Calgary biofilm reactor are related to the operating conditions that do not allow a proper similarity with real conditions of biofilm formation or biofilm inactivation in industrial systems. Moreover, it is not possible to properly control the hydrodynamic conditions. Other limitations are related to its relatively low working volume and sampling area for biofilm analysis. Besides, its operating conditions are limited to a batch mode. The drip flow biofilm reactor and the rotating disk reactor have some common limiting aspects and disadvantages, due to the use of flat surfaces and the flow changes in the boundaries of the adhesion surfaces. Moreover, these reactors do not have a significant sampling area and it is not feasible to evaluate different hydrodynamic conditions or even to use mechanical treatments for biofilm removal. The operating conditions of these reactors do not allow a proper similarity with real conditions of biofilm formation or biofilm inactivation.

A further state of the art analysis also reveals some devices were developed to study and monitor biofilms in pilot and real DWDS, such as the Pennine Water Group coupon and the Bioprobe monitor. Pennine Water Group (PWG) coupon: The PWG coupon can be inserted directly into pipes, and is comprised of two parts, an "outer coupon" and an "insert". The outer coupon retains the curvature of the pipe and fits into a hole made in a removable and flanged identical pipe section. The coupon is fixed with a gasket to a section pipe. The insert is engineered flat to allow microscopic analysis and it fits inside the outer coupon in a way to allow the outer surface to be in direct contact with the water.

Bioprobe monitor: The Bioprobe monitor consists on a pipe where a coupon holder (denominated acetal) is inserted, being the coupon surface flushed with the pipe wall. The bioprobe monitor was specifically designed to study biofilm growth within a pipe system.

The PWG coupon and the Bioprobe monitor have some common limiting aspects and disadvantages, such as the reduced sampling area provided by the employed coupons, the limitation and difficulty in controlling the operational conditions and the change of the flow pattern due to the geometrical configuration of the said reactors. Besides that, it is not possible to apply simultaneously different chemical treatments for biofilm inactivation and removal in these reactors.

<NPL> discloses reactors to study drinking water biofilms, in particular devices that allow biofilm formation under controlled conditions of physical (flow velocity, shear stress, temperature, type of pipe material, etc), chemical (type and amount of nutrients, type of disinfectant and residuals, organic and inorganic particles, ions, etc) and biological (composition of microbial community - type of microorganism and characteristics) parameters, ensuring that the operational conditions are similar as possible to in drinking water distribution systems conditions in order to achieve results that can be applied to the real scenarios.

<NPL> relates to a rotating drum biofilm annular reactor, consisting of a concentric outer cylinder (inner diameter of <NUM>) and a rotating inner cylinder with a total height of <NUM>. The reactor contained <NUM> removable flat stainless steel coupons on its inner wall to permit sampling of the biofilms.

Stoodley and Warwood "<NPL>, provides an analysis of various types of biofilm reactors, concentrating on the use of flow cells and the annular reactor for biofilm research and monitoring.

<NPL> discloses a rotating cylinder reactor used in drinking water biofilm studies with polyvinyl chloride (PVC) as substratum.

The reactor described and claimed in the present invention, was developed to overcome the limitations of the available biofilm reactors, allowing reliable studies of biofilm formation on cylindrical surfaces and their inactivation and removal, which are an integrated part of the said reactors. The said reactors may be operated under controlled conditions mimicking the ones found on industrial surfaces, particularly the conditions influenced by physical variables (shear stress, temperature, type of pipe material), chemical variables (type and amount of nutrients, type and concentration of disinfectant and residuals, organic and inorganic particles and ions) and biological variables (composition and density of the microbial community).

The advantages related to the reactors according to the present invention are significant such as their ideal and well mixed conditions, with the absence of Taylor vortices; their higher surface area for biofilm formation; the possibility of producing larger biofilm amounts for further analysis; the possibility of using simultaneously different materials for biofilm formation; the easy sampling steps; the reduction of changes in the flow patterns on the surface where biofilms are formed; and the possibility of applying different chemical and mechanical treatments per assay. Those are aspects that will be evident for a person skilled on the art in the detailed description and in the embodiments represented in drawings.

In order to promote an understanding of the principles according to the embodiments of the present invention, reference will be made to the embodiments shown in the figures and to the language used to describe them. In any event, it is to be understood that there is no intention to limit the scope of the present invention to the content of the figures, the invention being defined in the appended claims. Any subsequent changes or modifications of the inventive features herein and any further applications of the principles and embodiments of the invention illustrated which would normally occur to a person skilled in the art having the possession of this disclosure are within the scope of the claimed invention as defined in the appended claims.

The invention is defined by a reactor for biofilm formation comprising a head as defined in the claims.

Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

The present invention as defined in the claims refers to a head (<NUM>), represented in the <FIG>, for a reactor for biofilm formation (<NUM>), comprises a principal cover (<NUM>) that includes at least a vertical hole (<NUM>), represented in the <FIG> and <FIG>, wherein it is inserted a vertical shaft (<NUM>) into each vertical hole (<NUM>) and each vertical shaft (<NUM>) comprises at least a fixed cylinder (<NUM>), preferably three cylinders (<NUM>), wherein the cylinders (<NUM>) are arranged in series. Furthermore, the head (<NUM>) comprises a system for rotating (<NUM>) each respective vertical shaft (<NUM>) around its own axis.

The present invention as defined in the claims refers to a reactor for biofilm formation (<NUM>), as shown in <FIG> and <FIG>, wherein the head (<NUM>) is inserted into a platform for biofilm formation (<NUM>), wherein the platform for biofilm formation (<NUM>) comprises:.

Furthermore, each vertical shaft (<NUM>) of the invention, represented in the <FIG> and <FIG>, is held in the principal cover (<NUM>) and is suspended inside each vessel (<NUM>).

The feed and drainage cover (<NUM>), represented in the <FIG> and <FIG>, comprises four horizontal drainage holes (<NUM>).

The reactor for biofilm formation (<NUM>), represented in the <FIG> and <FIG>, operates under one of the selected conditions e.g. under batch, fed batch or continuous operating conditions.

An embodiment outside the subject-matter of the claims but useful for understanding the disclosure, refers to a reactor for biofilm inactivation and removal from the adhesion surface (<NUM>), represented in the <FIG> and <FIG>, comprising the head (<NUM>), wherein the head (<NUM>) is inserted into a platform for biofilm inactivation and removal from the adhesion surface (<NUM>), wherein the platform for biofilm inactivation and removal from the adhesion surface (<NUM>) comprises:.

Furthermore, each vertical shaft (<NUM>), represented in the <FIG> and <FIG>, is held in the principal cover (<NUM>) and suspended inside each vessel (<NUM>').

In the present invention the feed and drainage cover (<NUM>), represented in the <FIG>, comprises:.

Furthermore, in the present invention, the feed and drainage cover (<NUM>) having:.

in equal number to the number of the vertical vessels (<NUM>).

Furthermore, in the present invention, the feed and drainage cover (<NUM>) further comprises a system for feeding and draining, not represented in the figures that includes:.

In a preferred embodiment of the present invention, the cover (<NUM>), represented in the <FIG>, comprises:.

Furthermore, in another preferred embodiment according to the present invention, the cover (<NUM>) has vertical insertion holes (<NUM>') and vertical cavities (<NUM>') in equal number to the number of the vertical vessels (<NUM>'), as represented in the <FIG> and <FIG>.

In a preferred embodiment of the present invention, each vertical vessel (<NUM>') is tight and comprises:.

In a preferred embodiment of the present invention the vertical vessel (<NUM>), represented in the <FIG> and <FIG>, being tight and comprises:.

In according to one of the respective embodiments of the present invention, the vertical vessel (<NUM>) and (<NUM>') may present other different working volumes than the working volume referred to in the previous paragraph.

In according to one of the respective embodiments of the present invention, the vertical vessel (<NUM>) and (<NUM>') is manufactured with a translucent material, such as polymethyl methacrylate or glass.

In one of several embodiments of the present invention, the translucent material of the vertical vessel (<NUM>) and (<NUM>') allows visualization of biofilm formation and the biofilm removal from the adhesion surface.

Furthermore, in the present invention, each vertical vessel (<NUM>) is interconnected through the interconnected base (<NUM>) that comprises a sump feed (<NUM>) and each vertical vessel (<NUM>) is independent from one another and each vertical vessel (<NUM>) is fed by the vertical and central feed vessel (<NUM>), which is interconnected with all the vertical vessels (<NUM>) through the sump feed (<NUM>) of the interconnected base (<NUM>).

In a preferred embodiment of the present invention, the cylinders (<NUM>) comprise:.

And the cylinders (<NUM>) being manufactured using a material selected from the list consisting of:.

Furthermore, the cylinders (<NUM>) are fixed in the vertical shaft (<NUM>), preferably being at a distance of about <NUM> from each other; and the cylinders (<NUM>) rotate around its own axis.

In a preferred embodiment of the present invention the interconnected base (<NUM>), represented in the <FIG>, comprises:.

In a preferred embodiment of the present invention, the base (<NUM>), represented in the <FIG>, comprises:.

In a preferred embodiment of the present invention the interconnected base (<NUM>), represented in the <FIG>, of the reactor for biofilm formation (<NUM>) has the base cavities (<NUM>) in equal number to the number of the vertical vessels (<NUM>).

In a preferred embodiment of the present invention, the system for rotating (<NUM>) comprises a motor, not represented in the figures, to rotate at least one vertical shaft (<NUM>), not represented in the figures, wherein the motor rotates synchronously each of the vertical shafts (<NUM>).

Furthermore, the system for rotating (<NUM>) comprises:.

A head (<NUM>), represented in the <FIG> and <FIG>, for a reactor for biofilm formation (<NUM>) , comprises a principal cover (<NUM>) that includes at least a vertical hole (<NUM>), wherein it is inserted a vertical shaft (<NUM>) into each vertical hole (<NUM>) and each vertical shaft (<NUM>) comprises at least a fixed cylinder (<NUM>).

Furthermore, the head (<NUM>) comprises a system for rotating (<NUM>) each respective vertical shaft (<NUM>) around its own axis.

As represented in <FIG>, of the present invention, the vertical shaft (<NUM>) comprises cylinders (<NUM>) which are equally distant from each other and arranged in series.

In one of several embodiments of the present invention, the cylinder (<NUM>), as represented in the <FIG>, comprises a cylindrical shape, a sampling surface including:.

In one of several embodiments of the present invention, the cylinder (<NUM>) may have other different measurements for the sampling surface and the fixation section than the measurements mention to in the previous paragraph.

In one of several embodiments of the present invention, the use of a cylinder (<NUM>) with a higher surface area increases the sampling area, improving the homogeneity of biofilm and decreasing the effects of changes in flow patterns in the boundaries of each cylinder, a phenomenon commonly observed in alternative reactors.

It is possible to form biofilms uniformly, independent of the cylinder (<NUM>) position.

In one of several embodiments of the present invention, different materials can be used as substratum for biofilm formation.

In one of several embodiments of the present invention, the cylinder (<NUM>) may be made of only one material or different materials simultaneously, such as:.

In one of several embodiments of the present invention, the coatings and surface coats, above mentioned in the previous paragraph, comprise a nanomaterial or a surface chemically modified.

In one of several embodiments of the present invention, materials may be selected according to the objective of the work and may be metals and metallic alloys, plastics, glass and also modified materials and surfaces.

As can be seen in the respective <FIG> and <FIG>, the present invention comprises a reactor for biofilm formation (<NUM>).

In the <FIG> and <FIG> is represented a head (<NUM>), which is common to the reactor for biofilm formation (<NUM>).

In one of several embodiments of the present invention, the reactor for biofilm formation (<NUM>), represented in the <FIG>, comprises:.

In an embodiment outside the subject-matter of the claims but useful for understanding the disclosure, the reactor for biofilm inactivation and removal from the adhesion surface (<NUM>), represented in the <FIG>, comprises:.

The platform for biofilm formation (<NUM>), represented in the <FIG>, comprises:.

In one of several embodiments of the present invention, the reactor for biofilm formation (<NUM>), as represented in the <FIG> and <FIG>, comprise at least a vertical support shaft (<NUM>).

In one of several embodiments of the present invention, the reactor for biofilm formation (<NUM>), as represented in the <FIG> and <FIG>, according to the one of the respective embodiments of the invention, comprise preferably four vertical support shaft (<NUM>).

In one of several embodiments of the present invention, according to the one of the respective embodiments of the invention, the vertical support shaft (<NUM>) is manufactured in aluminium and stainless steel.

In one of several embodiments of the present invention, the system for rotating (<NUM>), not represented in the figures, comprises a motor, to rotate at least a vertical shaft (<NUM>).

In one of several embodiments of the present invention, the motor synchronously rotates each of the vertical shaft (<NUM>).

In one of several embodiments of the present invention, the system for rotating (<NUM>) each vertical shaft (<NUM>) comprises:.

According to the present invention, the feed and drainage cover (<NUM>) comprises a system for feeding and draining, not represented in the figures, which includes:.

As represented in the <FIG>, <FIG> and <FIG>, in one of several embodiments of the present invention, the vertical shaft (<NUM>) is held in the principal cover (<NUM>) and suspended inside the vessel (<NUM>).

In an embodiment outside the subject-matter of the claims but useful for understanding the disclosure, , the platform for biofilm inactivation and removal from the adhesion surface (<NUM>), represented in the <FIG>, comprises:.

According to the present invention, the feed and drainage cover (<NUM>), represented in the <FIG>, <FIG> and <FIG>, comprises:.

The cover (<NUM>), represented in the <FIG>, <FIG> and <FIG>, comprises:.

In one of several embodiments of the present invention as represented in the <FIG> and <FIG>, in the feed and drainage cover (<NUM>), the number of:.

is equal to the number of the vertical vessels (<NUM>), represented in the <FIG>.

As represented in the <FIG> and <FIG>, in the cover (<NUM>), the number of the vertical insertion holes (<NUM>') and the vertical cavities (<NUM>') is equal to the number of the vertical vessels (<NUM>'), as represented in the <FIG> and <FIG>.

The reactor according to the present invention may be constructed in transparent materials, allowing a proper observation of the biofilm formation and removal.

In one of several embodiments of the present invention, the feed and drainage cover (<NUM>) and cover (<NUM>) are manufactured with a translucent material, such as a polymethyl methacrylate or glass.

In one of several embodiments of the present invention, the interconnected base (<NUM>) and the base (<NUM>) are manufactured with a translucent material, such as polymethyl methacrylate or glass.

As represented in the <FIG>, each of the vertical vessels (<NUM>) of the reactor for biofilm formation (<NUM>) are interconnected through the interconnected base (<NUM>) that comprises a sump feed (<NUM>).

In an embodiment outside the subject-matter of the claims but useful for understanding the disclosure, as represented in the <FIG> and <FIG>, in one of several embodiments of the present invention, each of the vertical vessels (<NUM>') of the reactor for biofilm inactivation and removal from the adhesion surface (<NUM>) are independent from one another.

In one of several embodiments of the present invention, when the reactor for biofilm formation (<NUM>) operates under batch operating condition, a bacterial culture (<NUM>) and an initial nutrient medium (<NUM>) are fed to the said reactor for biofilm formation (<NUM>).

In one of several embodiments of the present invention, when the reactor for biofilm formation (<NUM>) operates under fed batch or continuous operating conditions, its operation comprises feeding:.

In an embodiment outside the subject-matter of the claims but useful for understanding the disclosure, the reactor for biofilm inactivation and removal from the adhesion surface (<NUM>) comprises feeding a chemical agent (<NUM>) and a neutralizer solution (<NUM>).

The reactor for biofilm formation (<NUM>) of the present invention is adapted to carry out assays with the same initial nutrient medium (<NUM>) or diluted nutrient medium (<NUM>), using the interconnected base (<NUM>). Alternatively, it is possible to perform simultaneous assays with different initial nutrient media (<NUM>) using the base (<NUM>) only under batch operating condition.

As it will be understood by a person skilled in the art, each vertical shaft (<NUM>) may be configured to rotate in a specific rotational speed. Therefore, it is possible to perform simultaneous assays in both reactor for biofilm formation (<NUM>) or reactor for biofilm inactivation and removal from the adhesion surface (<NUM>) employing different rotational speeds.

In an embodiment outside the subject-matter of the claims but useful for understanding the disclosure, in the case of the reactor for biofilm inactivation and removal from the adhesion surface (<NUM>), a base (<NUM>) composed by, for example, four independent vessels may be used to apply different chemical treatments simultaneously, with at least two replicates for each condition.

The reactor for biofilm formation (<NUM>) overcomes the limitations of prior art technologies and their main advantages are:.

Data relating the rotational speed (in rotation per minute - rpm) with the Reynolds number (Re - dimensionless) and shear stress (in Pascal - Pa) on the cylinder (<NUM>) surface are provided in the table <NUM>.

As it will fully to be understood by a person skilled in the art, when the Reynolds number is relatively small, the biofilm formed has a less cohesive structure, which can be more easily destroyed. In an opposite direction, under a higher Reynolds number, the biofilm formed is more adapted to the stressful conditions, having a higher cohesion, making its inactivation and removal more difficult.

The calculation of rotational Reynolds number (Re) is based on the annulus gap between cylinder surface and the vessel wall: <MAT> where a is the cylinder diameter, b is the inner diameter of the vessel, ρ is the density of nutrient media, N is the rotational speed and µ is the viscosity of nutrient medium. The shear stress for a rotating cylinder is given by: <MAT> where f is the Fanning factor and v is the fluid velocity in the cylinder surface. The Fanning factor (f) for a rotating cylinder is calculated according to: <MAT>.

The velocity of fluid in the cylinder surface is given by: <MAT>.

Disclosed herein is also an integrated process that comprises two processes, concretely the first one, the process for biofilm formation, and the second one, the process for biofilm inactivation and removal from the adhesion surface, which comprises the following steps:.

The present invention refers to a process for biofilm formation, by means of the reactor for biofilm formation (<NUM>), which comprises the following steps:.

In one of several embodiments of the present invention, the step i) cleaning and disinfecting the cylinders (<NUM>) and the vertical vessels (<NUM>), comprises the following substeps:.

In a preferred embodiment of the present invention, the step of ii) biofilm formation, when the reactor for biofilm formation (<NUM>) operates under batch operating conditions, comprises the following substeps:.

In a preferred embodiment of the present invention, the step of ii) biofilm formation, when the reactor for biofilm formation (<NUM>) operates under fed batch operating conditions, comprises the following substeps:.

In a preferred embodiment of the present invention, the step of ii) biofilm formation, when the reactor for biofilm formation (<NUM>) operates in continuous operating conditions, comprises the following substeps:.

In one of the several embodiments of the present invention, the bacterial culture (<NUM>) used for biofilm formation comprises the bacterium, carbon, nitrogen and phosphorous sources.

In one of several embodiments of the present invention, the initial nutrient medium (<NUM>) used for biofilm formation comprises carbon, nitrogen and phosphorous sources.

In one of several embodiments of the present invention, the sterile diluted nutrient medium (<NUM>), used for biofilm formation comprises <NUM>-fold diluted carbon, nitrogen and phosphorous sources from the initial nutrient medium (<NUM>) in adequate buffer, for example, phosphate buffer.

The table <NUM> describes the possible composition of the initial nutrient medium (<NUM>) and of the feeding medium for biofilm formation by Bacillus cereus or/and Escherichia coli or/and Pseudomonas fluorescens or/and Staphylococcus aureus (single- or mixed-biofilms).

Disclosed herein is further a process for biofilm inactivation and removal from the adhesion surface, by the means of the reactor for biofilm inactivation and removal from the adhesion surface (<NUM>), which comprises the following steps:.

In one of several embodiments of the present invention, the step i) each of the vertical vessel (<NUM>) is fill with the same chemical agent (<NUM>) or different chemical agents (<NUM>).

An embodiment, , the chemical agent (<NUM>), for biofilm inactivation and removal from the adhesion surface, is for example a disinfectant solution, and may be selected from one or more of the groups: aldehydes (e. glutaraldehyde, ortho-phthalaldehyde); peroxides (e. hydrogen peroxide, peracetic acid); halogens (e. bleach at a maximum of <NUM>% (v/v), sodium hypochlorite; chlorine dioxide; iodine); biguanides; quaternary ammonium compounds; phenolics; phytochemicals; organic acids; inorganic acids; anionic surfactants; alcohols; and nanoparticles;.

Biofilm is formed on the surface of each cylinder (<NUM>), in the reactor for biofilm formation (<NUM>), which comprises:.

An embodiment useful for understanding the invention, biofilm inactivation and removal from the adhesion surface comprises chemical agent (<NUM>), neutralizer solution (<NUM>), and inactivation and removal from the adhesion surface by reactor for biofilm inactivation and removal from the adhesion surface (<NUM>).

Claim 1:
A reactor for biofilm formation (<NUM>) comprising a head (<NUM>) for a reactor for biofilm formation (<NUM>), comprising:
a principal cover (<NUM>), wherein the principal cover (<NUM>) comprises:
a plurality of vertical holes (<NUM>), wherein it is inserted a vertical shaft (<NUM>) into each one of the vertical holes (<NUM>)
wherein each vertical shaft (<NUM>) comprises a plurality of fixed cylinders (<NUM>), wherein the cylinders (<NUM>) are arranged in series; and the head (<NUM>) further comprising:
a system for rotating (<NUM>) each respective vertical shaft (<NUM>) around its own axis;
wherein the head (<NUM>) is inserted into a platform for biofilm formation (<NUM>), wherein the platform for biofilm formation (<NUM>) comprises:
- a feed and drainage cover (<NUM>);
- a plurality of vertical vessels (<NUM>), preferably four vertical vessels (<NUM>);
- a vertical and central feed vessel (<NUM>);
- a plurality of vertical support shafts (<NUM>), preferably four vertical support shafts (<NUM>); and
- an interconnected base (<NUM>);
and the vertical shaft (<NUM>) being:
- held in the principal cover (<NUM>); and
- suspended inside the vessel (<NUM>);
wherein the feed and drainage cover (<NUM>) comprises:
- a plurality of vertical insertion holes (<NUM>), for insertion of each four respective vertical vessel (<NUM>);
- a vertical feed central hole (<NUM>), for insertion of the respective vertical and central feed vessel (<NUM>);
- a plurality of vertical cavities (<NUM>), located at the bottom of the feed and drainage cover (<NUM>), for fitting the respective vertical vessel (<NUM>);
- a plurality of vertical holes for support (<NUM>), for insertion of each respective four vertical support shafts (<NUM>); and
- a plurality of horizontal drainage holes (<NUM>), located at the side face of the feed and drainage cover (<NUM>), for drainage of the respective vertical vessel (<NUM>);
and the feed and drainage cover (<NUM>) further comprising a system for feeding and draining that includes an external pump, for feeding the vertical and central feed vessel (<NUM>) through an external tube.