FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION

“A bio-reactor having a plurality of surface area enhancers and a method for enhancing a biological and/or biochemical reaction in the same”

APPLICANTS:

Name : Eco Positive Solutions (India) Pvt. Ltd.
Nationality : Indian
Address : 730, behind BDA complex, 3rd block ,
Koramangala, Bangalore-34

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

TECHNICAL FIELD
[001] The disclosed embodiments relate to a bio-reactor having a plurality of surface enhancers and a method for enhancing a biological and/or biochemical reaction in the same and more particularly but not exclusively to a bio-digester tank having a plurality of surface enhancers and a method for enhancing a biological and/or biochemical reaction in the same.

BACKGROUND
[002] Anaerobic bio-digestion is defined as the conversion of organic waste(s) into a methane rich Biogas, an energy source by a fermentation process involving living organisms. This process is generically known as anaerobic digestion. Anaerobic digestion essentially occurs in two steps. In the first, organic matter is converted by hydrolytic and acidogenic bacteria to intermediates such as VFA (mainly acetic acid) , CO2 and H2 . In the second step, these intermediates are converted to methane by methanogenic bacteria. Anaerobic Digestion is a naturally-occurring process commonly utilized as a pollution control means in municipal sewage treatment, livestock waste handling, energy generation etc. worldwide.

[003] Digestion of organic waste consists of a set of processes used for reducing volumes of biodegradable waste and simultaneously producing biogas. In digestion, the organic waste (Feed stock) is mixed with a culture of bacteria in a bio-digester tank and is then digested under anaerobic conditions. In digestion, the organic waste is decomposed, thus producing biogas, which primarily consists of methane and carbon dioxide, and digested effluent.
[004] Typically, a small scale anaerobic digestion process is implemented using a system having two tanks. One of the tanks is used as a bio-digester in which the slurry (Feed stock) is digested (i.e undergoes bio degradation) due to the metabolism of the active microbial biomass/bacteria and the second tank is used as a biogas holder for storing the gas.
[005] Further, with regards to the bio-digester tank, one of the facts documented in studies conducted across the world is that (active microbial biomass)/bacteria cultures which are responsible for the bio-digestion and biogas formation prefer to attach and grow on the solid surfaces rather than being suspended in the slurry inside the bio-digester tank. As the active microbial biomass is attached to the solid surface it can be retained in the digester for a longer period of time
[006] It has to be noted that, at present, most of the bio-digester tanks available in the markets and/or used in the industries are cylindrical in shape. Further, bio digestion in the conventional bio-digester tanks may not be very effective with short hydraulic retention time because the bacteria cultures prefer to attach and grow on solid surfaces as compared to be suspend in the slurry. This solid surface is usually provided by the inner periphery of the bio-digester tank. Therefore, a portion of the slurry away from the inner periphery will not be reacted upon as effectively by the bacteria if slurry is not agitated thereby adversely/negatively affecting the production of the gas, rate of biogas production and hence reducing the efficiency of the bio-digester for a given specific (hydraulic retention time) interval of time. Additionally, it can be noted that during a re-filling of subsequent loads of the slurry into the bio-digester tank, a portion of the previous load of slurry which has been reacted upon by the bacteria gets drained out from bio-digester. In the process of draining out the previous load of slurry, chances of the suspended bacteria colonies or active microbial colonies getting washed away are high compared to attached bacteria colonies or active microbial biomass, thereby decreasing the number of bacteria inside the bio-digester tank which again results in the decreased efficiency of the bio-digester for a given interval of time. This gets restored over a time interval as the reproduction of microorganisms (bacteria) takes place inside the digester. This is a very slow process in case of methenogenic bacteria as the regeneration time required for these bacteria is high.
OBJECT OF INVENTION
[007] The principal object of this invention is to provide a plurality of surface enhancers in a bio-reactor tank and a method for enhancing a biological and/or biochemical reaction in the same.
[008] Another object of the invention is to provide a movable surface enhancer for increasing a microbial concentration (per unit area) and contact area between a biodegradable material and bacteria and further configured to agitate the contents inside the bio-bioreactor.

STATEMENT OF INVENTION
[009] Accordingly the invention provides a bio-reactor having a tank adapted to be filled with slurry. A slurry inlet is provided for feeding the slurry into the tank. The slurry inlet is configured to be in fluid communication with the tank. Further, a stirrer rod is provided inside the tank. A plurality of surface enhancers each defining at least one opening are engaged on the stirrer rod at predetermined intervals.
[0010] Further, a first propeller blade extending towards an inner periphery of the tank and having a plurality of bristles is secured to the stirrer rod.
[0011] There is also provided a method for enhancing a microbial concentration per unit area and direct contact between a biodegradable material and bacteria’s in a bio-reactor. It should also be noted that in this description each of the terms such as bacteria, bacteria colonies, active microbial mass are used to mean micro organisms that facilitates bio-digestion of the slurry. The method includes feeding a predetermined amount of slurry into the bio-reactor, providing a plurality of surface enhancers inside the bio-reactor. The surface enhancers are configured to be mounted on to a stirrer rod inside the bio-reactor. Further, the method also includes allowing the bacteria colonies to grow on each of the surface enhancers and an inner periphery of the bio-reactor and stirring the slurry.
[0012] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
[0013] This invention is illustrated in the accompanying drawings, through out which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0014] FIG. 1 depicts a bio-digester tank employing a plurality of surface enhancers, according to embodiments as disclosed herein; and
[0015] FIGs. 2A-2D each depicts a shape of the surface enhancer which can be employed in the bio-digester tank.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

[0016] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0017] The embodiments herein achieve an improved biochemical reaction between biodegradable material in the slurry and the bacteria culture by providing surface for improved microbial concentration per unit area and enhancing a contact area between the biodegradable material and the bacteria culture or active microbial mass via a plurality of surface enhancing elements. Referring now to the drawings, and more particularly to FIGS. 1 through 2D, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

[0018] Further, it has to be noted that for the purpose of description the below embodiments describe the invention by considering the bio-digester tank, modifications can be made to the invention to be employed in other bio-reactors which require surface enhancing. Such modifications and adaptations will be within the scope of this invention.
[0019] FIG. 1 depicts a bio-digester tank 20 adapted to contain slurry or feed stock therein. The bio-digester tank 20 is configured to be in fluid communication with a slurry inlet 22. The slurry inlet 22 is provided with funnel 22a for feeding the slurry thereto. A regulator 22r is provided between the slurry inlet 22 and the bio-digester tank 20 for regulating a flow of the slurry into the bio-digester tank 20 from the slurry inlet 22. Further, the bio-digester tank 20 is provided with a slurry outlet 34 at a top portion thereof. A drain outlet 50 is provided near a bottom portion of the bio-digester tank 20. A gas outlet pipe 36p is provided at the top portion of the bio-digester tank 20. The gas outlet pipe 36p includes a regulator 36a which regulates a flow of the gas from the bio-digester tank 20 to a gas holder (not shown) where the gas is stored. The gas stored in the gas holder (not shown) is then transferred to a load (not shown).

[0020] Further, the bio-digester tank 20 includes a stirrer rod 24 extending from the top portion of the bio-digester tank 20 through an opening (not shown) towards the bottom portion thereof. A gas seal covering C is adapted to seal the opening partially so as to rotatably accommodate the stirrer rod 24. A first end 24a of the stirrer rod 24 is rotatably engaged with a base support 26 inside the bio-digester tank 20. The base support 26 is mounted on a bottom surface of the bio-digester tank 20. A second end 24b of the stirrer rod 24 is engaged with a wind shaft 32. The wind shaft 32 is adapted to hold a plurality of wind blades 30. The wind blades 30 are provided to convert a motion of the wind into rotary motion of the stirrer rod 24. A first set of propeller blades 40a is provided on the stirrer rod 24 inside the bio-digester tank 20. Further, a second set of propeller blades 40b is provided near the first end 24a of the stirrer rod 24. Each of the second set of the propeller blades 40b is provided with a plurality of bristles 42 extending from the second blades 40b towards the bottom portion of the bio-digester tank 20.
[0021] Further, a plurality of surface enhancers 80 are adapted to be engaged along the length of the stirrer rod 24 and inside the bio-digester tank 20 at predetermined intervals. The surface enhancers 80 are engaged to the stirrer rod 24 through a cylindrical sleeve 14 so as to rotate upon a rotation of the stirrer rod 24. It is to be noted that the surface enhancers 80 may be engaged to the stirrer rod 24 by any other engagement means know in the art as long as the surface enhancers are suitably secured on the stirrer rod 24. Further, the surface enhancers 80 are adapted to define irregular surface profile that provides improved surface area per unit area compared to a plain surface.
[0022] Now referring to FIGs 2A-2D, different surface enhancers are depicted for use in the bio-digester tank 20. FIG. 2A depicts the surface enhancer 80 having a frame 100. A plurality of spaced apart wires or threads 120 are secured inside the frame 100. It is also within the scope of the present invention to replace wires or threads 120 with horizontal plates (not shown). FIG. 2B depicts the surface enhancer 80 having a plate 200 defining a plurality of aperture 220. The apertures 220 are spaced away from each other at predetermined intervals or at an irregular interval. The surface enhancer 80 as mentioned above may be produced from a mould, winding of irregular or uneven shape surface element on a frame of any geometric shape or by mechanical welding of the components.
[0023] FIG. 2C depicts the surface enhancer 80 having a frame 300. A plurality of spaced apart horizontal wires 320h and a plurality of spaced apart vertical wires 320v, respectively, are secured to the frame 300. Each of the vertical wires 320v intersects at different points on the horizontal wires 320h so as to define a mesh like grid structure. The surface enhancer 80 as mentioned above may be produced from a mould or by mechanical welding of the components.
[0024] FIG. 2D depicts the surface enhancer 80 having a plate 400 defining a plurality of projection 420p and a plurality of apertures 420a. The surface enhancer 80 as mentioned above may be produced from a mould or by mechanical welding of the components.
[0025] The wires 120, the apertures 220, the vertical and horizontal wires 320v, and 320h, the apertures 420a as depicted in FIGs. 2A, 2B, 2C, and 2D respectively, are spaced apart so as to allow a passage of the slurry when the surface enhancers 80 are rotated. Further, it should be noted that since a temperature inside the bio-digester tank 20 is one of the key parameter that directly affects the rate of biogas production & functioning of the methane generating bacteria inside the bio-digester tank 20, each of the frame 100, the wires 120 or the horizontal plates (not shown), the plate 200, the frame 300 and the vertical and horizontal wires 320v, and 320h, and the plate 400 should be made from a heat resistant material and should be flexible as well. The heat resistant feature eliminates heat absorbing and dissipation of the same by the surface enhancing elements. It is also within the scope of the invention to make the surface enhancers 80 from a non-metal or insulating material or any material which is a bad conductor of heat. The flexibility feature helps to improve a durability of the surface enhancer as it can withstand the stress created due to the bending & torsion forces produced during the agitation of the slurry. It can be understood by a person having ordinary skill in the art that the surface enhancers 80 can be made from any flexible material such as rubber, for example. Further, it should also be noted that the structure of the surface enhancers 80 as shown in each of the FIGs 2A-2D are for the purpose of describing the embodiments. However, many different structures and/or shapes for the surface enhancers 80 can be made and incorporated, depending upon the size and capacity of the bio-digester tank 20, without otherwise deviating from the intended function of the surface enhancers and without otherwise affecting the operation of the bio-digester tank 20.
[0026] In operation, slurry is fed to the slurry inlet 22 through the funnel 22a. The slurry is then allowed into the bio-digester tank 20 through the regulator 22r. The bio-digester tank 20 is allowed to be filled with the slurry until the slurry reaches a predetermined level inside the bio-digester tank 20. The slurry may be filled so that surface enhancer 80 provided near the top portion of the bio-digester tank 20 is completely immersed inside the slurry. Alternatively, the slurry may be filled depending upon the predetermined volume of gas that is to be generated. Upon the bio-digester tank 20 being filled with the slurry, the regulator 22r stops the supply of the slurry to the bio-digester tank 20. The bacteria culture reacts upon the slurry near an inner periphery of the bio-digester tank 20. Thereupon, a rotation of the stirrer rod 24 by the wind blades 32 rotates each of the surface enhancers 80, the first and second set of propeller blades 40a and 40b. Each of the surface enhancers 80 secured to the stirrer rod 24 may be of any of the structure and/or shape shown in FIGs. 2A-2D. For example, the surface enhancer 80 near the bottom portion of the bio-digester tank 20 may be of the structure and/or shape as depicted in FIG. 2C and the surface enhancer 80 near the top portion of the bio-digester tank 20 may be of the structure and/or shape as depicted in FIG. 2A. Alternatively, all of the surface enhancers 80 may be of an identical structure and/or shape. For example, all of the surface enhancers 80 shown in FIG. 1 may be of the structure/shape as depicted in FIG. 2D. The surface enhancing elements are provided away from an inner periphery of the digester tank so that the suspended organic or bio-degradable particles in the slurry contained throughout the bio-digester tank 20 may be reacted upon by the high concentration of microbial colonies attached onto the surface enhancer 80. Additionally, the above mentioned feature also prevents a washout of the bacteria’s along with the overflow of the slurry, in the form of effluent, when the next load of the slurry is loaded through the slurry inlet 22. In case of suspended bacterial growth system the active microbial mass/bacteria’s may get washed away along with the effluent overflow.
[0027] Further, the surface enhancers 80 provide an increased overall surface area contact between the slurry and the bacteria culture. The rotation of the surface enhancers 80 by the stirrer rod 24 results in the agitation of the slurry and further in redefining the direct contact of the slurry with the bacteria. That is to mention that a portion of the slurry that has not been reacted upon by the bacteria will come in direct contact with the active microbial biomass/bacteria upon rotating the stirrer rod 24 thereby enhancing a microbial concentration per unit area and direct contact between a biodegradable material and a bacteria colonies which results in an improved rate of digestion and gas production.
[0028] Further, the rotation of the stirrer rod 24 in turn rotates the second set of propeller blades 40b thereby causing the bristles 42 to sweep the bottom portion of the bio-digester tank 20. The above mechanism ensures that the sediment organic or bio-degradable particles at the bottom of the tank if any are mixed with the slurry. The gas generated by as a result of the reaction of the slurry by the bacteria gets accumulated in a top portion T of the bio-digester tank 20. Subsequently, the gas accumulated in the top portion T of the bio-digester tank 20 is transferred through the gas outlet pipe 36p to the gas holder (not shown) and the flow of the gas from the gas outlet pipe 36p is regulated by the regulator 36a.
[0029] Further, once the entire slurry in the bio-digester tank 20 is reacted upon by the bacteria, the reacted slurry is drained out through a slurry outlet 34 provided near the top portion T of the bio-digester tank 20.
[0030] The drain out 50 provided at the bottom portion of the bio-digester tank 20 is used for emptying the bio-digester tank 20 for maintenance or other purposes. The drain outlet 50 may employ a valve means or any other known means for allowing or stopping a passage of the slurry there through.
[0031] The various actions in the above method may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed may be omitted.
[0032] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

STATEMENT OF CLAIMS
1. A bio-reactor comprising:
a tank adapted to be filled with slurry;
a slurry inlet for feeding the slurry into the tank, said slurry inlet being in fluid communication with the tank; and
a stirrer rod adapted to be supported by the tank, said stirrer rod extending inside the tank, wherein
a plurality of surface enhancers each defining at least one opening are engaged on the stirrer rod at predetermined intervals;
a first propeller blade extending towards an inner periphery of the tank and having a plurality of bristles is secured to the stirrer rod.
2. The bio-reactor according to claim 1, wherein each of said surface enhancers are flexible.
3. The bioreactor according to claim 1, wherein each of the surface enhancers are bad conductors of heat.
4. The bio-reactor according to claim 1, wherein at least one of the surface enhancers defines an irregular rough surface.
5. The bio-reactor according to claim 1 further comprising a second propeller blade extending towards the inner periphery of the bio-digester tank.

6. The bio-reactor according to claim 1, wherein the stirrer rod is rotatbly moveable by a plurality of wind turbine blades.
7. The bio-reactor according to claim 1, wherein at least one of the surface enhancers defines a mesh structure.
8. A method for enhancing a microbial concentration per unit area and direct contact between a biodegradable material and a bacteria colonies in a bio-reactor, said method comprising:
feeding a predetermined amount of slurry into the bio-reactor;

providing a plurality of surface enhancers inside the bio-reactor, said surface enhancers being configured to be mounted on to a movable stirrer rod located inside the bio-reactor;

allowing the active microbial biomass or bacteria colonies to attach and grow on each of the surface enhancers and an inner periphery of the bio-reactor; and
stirring the slurry.
9. The method according to claim 8, wherein each of said surface enhancers are flexible.

10. The method according to claim 8, wherein each of the surface enhancers are bad conductors of heat.
11. The method according to claim 8, wherein at least one of the surface enhancers defines an irregular rough surface.
12. The method according to claim 11, wherein each of the surface enhancers defines at least one opening to allow a passage of the slurry when the surface enhancer is being rotated inside the bio-reactor.
13. The method according to claim 8, wherein the stirrer is a wind operated stirrer.
14. An apparatus substantially as herein above described in the specification with reference to the accompanying drawings.
15. A method substantially as herein above described in the specification with reference to the accompanying drawings.

Dated this 3rd September 2009

Dr. Kalyan Chakravarthy
Patent Agent

ABSTRACT
A bio-reactor and a method for enhancing a biological and biochemical reaction in the same, the bioreactor having a tank 20 adapted to be filled with slurry. A slurry inlet 22 is provided for feeding the slurry into the tank 20. The slurry inlet 22 is configured to be in fluid communication with the tank 20. Further, a stirrer rod 24 is provided inside the tank 20. A plurality of surface enhancers 80 each defining at least one opening are engaged on the stirrer rod 24 at predetermined intervals. The method includes the steps of feeding a predetermined amount of slurry into the tank 20, providing surface enhancers 80 inside the tank 20. The surface enhancers 80 are mounted on to a stirrer rod 24.
FIG. 1