|Title of Invention||
AN IMPROVED PROCESS FOR THE BIO-DEGRADATION OF EFFLUENT MATERIAL AND AN IMPROVED REACTOR THEREFOR
|Abstract||There is disclosed a process for the bio-degradation of effluent material such as herein described which comprises subjecting the effluent to oxygenation in the presence of microorganism in a fluidized condition characterized by the improvement wherein the bio-degradation is carried in the presence of electrical charges and an improved reactor therefor.|
|Full Text||THE PATENT ACT, 1070 COMPLETE SPECIFICATION
"AN IMPROVED PROCESS FOR THE BIO-DEGRADATION OF EFFLUENT MATERIAL AND AN IMPROVED REACTOR THEREFOR."
THERMAX LIMITED, HAVING REGISTERED OFFICE AT D-13, MIDC INDUSTRIAL AREA, CHINCHWAD, PUNE-411 019, MAHARASHTRA, INDIA, AN INDIAN COMPANY
The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.
process using an electrical current to enhance microbial growth and thereby improvement in bioreactor device for aerobic biodegradation of organic effluent.
The invention relates to the improved process of Vbiodegradation of various types of effluents such as municipal waste or industrial wastes using a novel method of electro-bio degradation of aerobic nature.
The process claimed in the invention is more efficient in biodegradation. The novel process uses a device wherein electrical energy is employed to enhance microbial growth thereby accelerate the rate of biodegradation in a fluidizedbed reactor compared to that of hitherto known process of aerobic biodegradation. The process is carried out in a novel device where in dimensionally stable anodes and cathodes are employed to supply an electrical charge. A power source to supply modified electrical field enhances the process efficiency. In the present invented process, pulsating electrical current mode is used with more advantage. Due to lower HRT, higher degradation rates can be achieved and various advantages to the process are obtained.
PRIOR ART PRACTICE
It is well known to subject effluents such as Municipal or industrial to biodegradation to meet stringent requirements of Pollution Control Boards.
Various process details and reactor construction are known in the art for this purpose and these are widely used world over.
In principle, Aerobic bio-reactors using different suitable biological cultures along with necessary oxygen supply and food supply to the bacterial population are in commercial practice.
Its also known to use reactors using suspended biomass as a work force or attached growth of biomass on different substrates fixed or fluidized.
The reactor efficiency has been further improved by increasing the efficiency of oxygen transfer from air or gas using proper air or oxygen distributing grids. The organic loading of reactors in the range of 2 to 12 kg/m3/day has been achieved by different designs so far.
In view of all these improvements and proper design
characteristics of the known art bio-reactors, it has been possible to achieve the following results /advantages.
The lowest Hydraulic Retention Time (HRT) of 8-10 hours for achieving 60 to 70 percent of reduction in COD using the latest fluidized bed technology in case where COD are higher than 4000 mg/litre and COD / BOD ratio of 2 .
DRAWBACKS OF THE PRIOR ART ;
In spite of the several advantages, the prior art process and reactor suffer from several drawbacks of which mention is made of the following and require problem solving suggestions.
The HRT increases with COD (Chemical Oxygen Demand) / BOD (Bio-logical Oxygen Demand) much less than 2 Kg per 1 Kg of BOD (Bio-logical Oxygen Demand) degraded in the conventional bio reactor.
The percentage packings with high surface area in the reactor vessel is not less than 50% volume/ volume wherever fluidized bed reactor (FBR) is used.
In the non fluidised bed reactor device, there are frequent chances of bulking and floating of bio mass with slight adverse operating conditions.
The Hydraulic Retention Time (HRT) is as high as 8 to 10 hours on minimum side and or as high as 20 to 30 hours on maximum side depending upon the design and technology used i.e. suspended growth, fixed film growth or fluidized bed growth of bio mass, fluidized bed reactor being the lowest.
However, with such high HRT, the vessel sizes for large capacity plants are very big and the air distribution, liquid feeding, fluidization pose operational problems.
Th commissioning and stabilizing period is also higher.
Further discussion on Prior Art:
The applicant is aware of the following prior art patents- US Patent No. 6432689. US Patent No. 6387267 and U.S. Patent No. 5458752
A discussion on each of these patents is given below.
US Patent 6432698: This patent relates to .a disposable bio-reactor for culturing micro-organism and cells. This is suitable for use by individuals not skilled in microbiology.
It is constructed of flexible or semi-flexible water proof sheets to form a container, which is designed to provide mixing, and gas exchange to micro-organisms cultured therein by bubbling gas through the culture.
This US patent is totally different from the Applicant's industrial bio-reactor.
The Applicant's reactor is specially provided with electrodes for inducing electrical current for helping bio-degradation of industrial effluents.
There is no such electrical cathode and anode in the cited US patent and its area of application and constructional details are different from the Applilcant's bio-reactor which is not made of flexible sheet material as in the US patent. The Applicant's bio-reactor is a ground based fixed rigid construction and has no flexible component therein.
US patent 6387267: This patent relates to a bio-reactor for liquid waste treatment. This US Patent is
primarily meant to treat pig manure. Further the reactor has no electrical anode or cathode and is
different from the Applicant's bio-reactor. '
Moreover, the US Patent suggests a perforated intermediate tubular media inside the enclosure.
The bio mass accumulates on the perforated media and the gas (Oxygen) bubbling upward through the media provides the oxygen necessary for the growth and survival of the micro-organism which also accumulate on the perforated media along with the bio mass.
This US patent also has nothing even remotely in common in construction or use with the Applicant's invention.
US Patent 5458752: This patent relates to an apparatus for the de-sulfurization of petroleum waste.
There is used anaerobic micro-organism to act as bio catalyst, which can remove sulfur from hydrocarbon molecules.
Right away this patent has nothing in common with the Applicant's invention.
However, there is a mention of electrodes at two levels (bottom and top) in the drawings of the U.S. Patent and these are provided entirely for the purposes of rupturing the aqueous drops into a plurality of micro droplets and to induce continuous coalescence and redispersion as the micro droplets travel through the organic phase thereby increasing the surface area of contact.
This enables the bio catalyst to react with the sulfur to produce hydrogen sulfide, which can be removed from the organic liquid in the reactor to produce sulfur free petroleum.
The reactor design construction and disposition of the electrodes are totally different, there being one inlet and one outlet each, both, at the bottom and at the top of the reactor. There is nothing in common with Applicant's invention.
None of the above three prior art patents either alone or in any combination, can destroy the novelty and inventive character of the Applicant's invention.
Objects of the Invention:
It is therefore a primary object of the invention to propose an improved process for the efficient bio-degradation of effluent with lower hydraulic retention time than hitherto possible.
It is another object of this invention to propose such an improved process which will require less oxygen demand and still ensure faster reaction rate.
It is a further object of this invention to propose such a process which will avoid the problems associated with the conventional fluidized bed techniques.
It is a still further object to propose a process which will require minimum supervision and control and can be easily practiced.
Yet another object of this invention is to propose a process using an improved biodegradathn reactor which will ensure effective distribution of air or oxygen and minimize the requirement.
It is a further object of this invention to propose a process using such an improved bio-reactor which will be smaller in size than so far possible and still provide faster reaction.
A further object is to propose a process of biodegradation with such an improved reactor which will have lesser hydraulic retention time and provide at the same time higher reaction rate.
A still further object is to propose such a process using an improved reactor where the overall energy inputs are reduced and shock load problems are eliminated.
It is also an yet another object to propose a process using such an improved reactor in which the commissioning and stabilizing period is considerably reduced, and the total packing volume is also minimized compared to that of hitherto known reactor.
These and other objects of the invention will be apparent from the following paragraphs.
STATEMENT OF INVENTION
According to this invention, there is provided a process for the bio-degradation of effluent material such as herein described which comprised subjecting the effluent to oxygenation in the presence of microorganism in a fluidized condition characterized by the improvement wherein the bio-degradation is carried in the presence of electrical charges.
In this process the electrical charging of the microorganism is carried out by inducing electrical current in the reactor by the electrode for effluent treatment and the electrical charge is induced by means of a set of electrodes made of anodes and cathodes held in the main body of the effluent material.
We have used Electrical charge of the order of 1.0 Am/cm to 1000.0 Am/cm and the electrical charge is induced for a period of time ranging between 30 minutes to as long as required.
In our experiment the electrical charge is induced at one time or at intervals of times and the duration of charge after different intervals is same or different as per exigencies.
The supply of oxygen can be either continuous or intermittent. The Electrodes can be arranged in groups of anodes and cathodes.
As to the choice of electrodes the anodes are selected from metals or coated metals such as titanium coated with precious metal oxide or any other dimensionally stable anodic material and the cathodes are selected from metals such as mild steel, aluminum, stainless steel, copper or any other suitable metal for use as cathode.
With reference to the geometry of the electrodes, the electrodes are selected from sheet metal or rod of desired configuration or from coated electrodes of desired shape and size.
According to this invention there is further provided an improved bio reactor for carrying out biodegradation of effluents comprising a main reactor body for holding the effluent to be treated, and inlet for the effluent and an outlet for the treated effluent and an outlet for sludge or waste material, said reactor also having air grids inside the main body and connected to an air source, the reactor being further provided with overflow arrangements characterized by the improvement that the reactor is provided with a set of electrodes connected to anelectrical energy source.
In the reactor the electrodes are made of set of anodes and cathodes single or multiple prepared out of sheet metal, expanded metal, metal rods or suitable conducting fibres which are bare or coated to make them dimensionally stable during bio electro degradation.
Electrodes can be coated electrodes. Electrodes are mounted on the inner wall of the reactor body with suitable insulating arrangements in one or more horizontal planes or at any desired location.
The electrodes can be mounted horizontally or angularly as may be required.
The electrodes can be mounted in various manners according to the design of the reactor. For example we have carried out experiments with bio reactor wherein the electrode sets are suspended from the top of the reactor supported on a support plate with proper insulation.
We have further experimented with the bio reactor wherein the set of electrodes with proper insulation are mounted on the outer wall of the central air grid arrangement described in the description of the device. In one such case the electrodes were mounted horizontally in another they were mounted angularly and in both instances the electrodes were mounted at different locations around the central air grid.
These anodes are made of from metals or coated metals such as Titanium coated with precious metal oxide or any other dimensionally stable anodic material and cathodes are made of metals such as mild steel, aluminum, stainless steel, copper or any other suitable metal for use as cathode.
It is to be noticed that the above statements clearly establish that there is a wide choice for the types of electrodes to be used. It is our intention that all types of electrodes which meet the basic requirements of the invention are to be considered as features of the invention.
It will also be observed that the above statements further establish that the shape and configuration of the electrodes are not very material or an aspect of the invention. Depending upon the reactor design any convenient shape and any convenient size of the electrodes can be used.
It will further be observed that the manner of mounting the electrodes is also open to wide choice and here again depending upon the rector design and conditions of treatment, the various electrodes can be mounted in several layers each layer being on the same plane. It is also possible to mount the electrodes in different planes, for example in a zig-zag manner or in the manner of "S" curves or in any geometrical pattern.
It is also important to note that the electrodes can be in the horizontal manner or mounted angularly pointing any direction.
Further possibilities are mounting the electrodes from the bottom floor of the reactor or suspending from the top of the reactor.
The basic requirement is to induce the current and reach as much area as possible of the medium being treated in the most effective manner and in the most economical condition.
There is thus a great number of choices in the reactor design to make it more versatile, effective, efficient and economical.
BRIEF DESCRIPTION OF THE INVENTED REACTOR FOR BIODEGRADATION :
This invention will now be more fully described with reference to the accompanying drawings in which :
Figure 1 shows schematically one version of the improved bio-reactor and
Figure 2 shows the view from the top of the reactor as shown by arrow 'X'.
DETAILED DESCRIPTION OF THE DRAWINGS :
As will be seen from the drawings, the bio-reactor (1) is provided with the usual accessories like feed pipe or inlet (2) for the effluent to be treated and outlet (3) for the treated effluent, conical bottom (4) for collection of waste sludge or disposable matter. There are air grids (5) inside the reactor at a lower level which are connected to an air supply source (6). There are usual provisions for overflow arrangement to maintain a steady level of effluent under treatment.
Also seen are suspended substrates to enhance reaction between the biomass and bacteria.
The improved bio reactor has a number of electrode assemblies (7) provided in the reaction region. These electrode assemblies (7) are made ofdimensionally stable anodes (7a) and metal cathode (7b).
Anodes used are expanded metal type Titanium coated with mixed oxides of precious metals. However, dimensionally stable anodes either coated ones or from noble metals which are non-Corrosive can also be used.
These electrodes are arranged co-axially parallel to the central longer axis of the vessels and fixed in the invented reactor vessel with pre-designed space between anode and cathode surfaces to achieve the desired electrical charge at minimum Possible electrical energy.
Parallel electrode plates with required spacing and pre¬designed effective total area are also used. Though, cylindrical or parallel plate type configuration is mentioned here, it is not limited to these two configurations and number of other configurations and spacing patterns can be used in the invented vessel to give optimum efficiency by applying the electrical charge to vitalize the micro-organism such as bacteria and Yeast for biodegradation.
For the holding of electrode assembly in place in the invented reactor, number of engineering alternatives can be used.
For example electrodes can be supported on some means from near the bottom or held in position by fixing from top of the vessel.
These can also be supported on a central feed pipe used for feeding air or from the inner walls of the vessel with proper insulating arrangements, or angularly spaced from a central support throughout the liquid in the reactor for near equal distribution of electrical charge in the entire volume.
The power source used is a device to produce pulsating current though other forms of power source such as AC to DC are also usable in the current electro biodegradation to excite the active Micro organism.
Thus by using electrical energy in the invented bioreactor, aerobic biodegradation is improved having positive impact on COD reduction, organic loading, HRT, and volume of packing used in invented fluidised electro bio reactor.
Using the invented dectrobip reactor as well as fluidised bed bio reactor (FBR) of our pending Indian patent application No. 413/BOM/98) comparative quantitative biodegradation pilot / full scale studies were carried out.
While we have studied various sources of effluents with varying oxygen demands, we have found that the improved bio reactor is very versatile and can be adopted to suit the treatment of varied effluents ranging from municipal effluent to industrial effluents.
Examples of the performance of the same are given in the accompanying Table 1.
We report a comparative data of three tests carried out using a bio reactor of conventional type and a bio electro reactor of the invention to substantiate the objects of new invention and claims arising out of the invention (see the above Table 1).
Though examples are mentioned in case of two types of wastes and a few concentration of pollutants, the scope of application of the invented bioreactor is not restricted to these wastes only but can be applied to most of the effluents where biodegradation is possible.
It will be seen that in all three studies the hydraulic retention time dropped by about or more than 50%.
We have also carried out studies with other effluents and obtained satisfactory results.
It will be seen that for same size of reactor the volume of packing is also reduced though the capacity of the reactor to treat the effluent has increased as seen from the reduction in HRT (Table 1).
It is also seen from data in Table 1 that the loading factor (kg of COD per day /rri3 of reactor value) has also improved.
While we do not want to be bound by any theory or propound any theory, what is responsible for the improvement is the electrical charge imparted to the particles of micro organisms which enhance digestion at short HRT.
The electrical power source is so designed that the electrical potential difference gets adjusted to required value automatically once the applied current (Amperes) is fixed.
Different current densities can be applied to the electrodes arranged in either parallel or series by adjusting the ampere on the power source, thus bringing flexibility in operating conditions.
The electrode used in the comparative study was made of dimensionally stable anode using Titanium as base metal and mild steel as cathode.
Other types of electrodes can also be used.
The electrodes can be of any configuration and can be sheet metal or rod of metal or an expanded metal type. It is also possible to use metal coated sheet or rod substrate made of inert refractory or similar material as electrodes.
Anode is selected from Titanium expanded metal coated with precious metal oxides.
Cathode is selected from mild steel expanded metal.
We Claim :
1) A process for the bio-degradation of effluent material, such as synthetic waste, ion exchange resin factory waste which comprises subjecting the effluent to oxygenation continuously or at intervals in the presence of micro-organism in a fluidized condition characterized in that the bio-degradation is carried in the presence of electrical charges induced by means of a set of electrodes made of anodes and cathodes held in the main body of the effluent material, the electrical charge being of the order of 1.0 Am/cm to 1000.0 Am/cm for a period of time ranging between 30 minutes to as long as required and being induced at one time or at intervals of times, the duration of charge after different intervals being same or different.
2) An bio reactor forcairying out bio-degradation of effluents by the process of Claim 1 comprising a main reactor body for holding the effluent to be treated, and inlet for the effluent and an outlet for the treated effluent and an outlet for sludge or waste material, said reactor also having air grids inside the main body and connected to an air source, the reactor being further provided with overflow arrangements characterized by the improvement that the reactor is provided with a set of electrodes connected to an electrical energy source, the electrodes being made of set of anodes and cathodes single or multiple prepared out of sheet metal, expanded metal, metal rods or suitable conducting fibres which are bare or coated to make them dimensionally stable during bio-electro degradation.
3) A bio reactor as claimed in claims 2 wherein the electrodes are mounted on the inner wall of the reactor body with suitable insulating arrangements in one or more horizontal planes or at any desired location.
4) A bio reactor as claimed in Claim 3 wherein the electrodes are mounted horizontally or angularly as desired.
5) A bio reactor as claimed in claim 2 wherein the electrode sets are suspended from the top of the reactor supported on support plate with proper insulation.
6) A bio reactor as claimed in claim 2 wherein the set of electrodes with proper insulation are mounted on the outer wall of the central air grid arrangement either horizontally or angularly in one or more planes or locations.
7) A bio reactor as claimed in claims 2 to 6 wherein the anodes are made from metals or coated metals such as titanium coated with precious metal oxide or any other dimensionally stable anodic material and cathodes are made of metals such as mild steel, aluminium, stainless steel, copper or any other suitable metal for use as cathode.
8) An improved process for biodegradation of effluents substantially as herein described.
9) An improved bio reactor substantially as herein described with reference to the accompanying drawings
Dated the 25th day of February 2000.
DILIP WAMAN BAPAT For THERMAXLIMITED
|Indian Patent Application Number||175/MUM/2000|
|PG Journal Number||41/2007|
|Date of Filing||01-Mar-2000|
|Name of Patentee||THERMAX LIMITED|
|Applicant Address||D-13, MIDC INDUSTRIAL AREA, CHINCHWAD, PUNE 411 019, MAHARASHTRA, INDIA.|
|PCT International Classification Number||N/A|
|PCT International Application Number||N/A|
|PCT International Filing date|