FR2812287A1 - Bacterial composition for pre-treatment of effluent containing animal or vegetable organic fats comprises bacterial strain Klebsiella Oxytoca, and Serratia Odorifera and-or Aeromonas Hydrophyla strains - Google Patents

Abstract

Bacterial composition for degradation of organic fatty substances comprises mainly bacterial strain Klebsiella Oxytoca and additionally Serratia Odorifera and/or Aeromonas Hydrophyla strains. Independent claims are also included for: (a) use of the bacterial composition for treatment/pre-treatment of effluents carrying fatty organic substances, especially effluents from food or agriculture-food industry; more specifically use of bacterial composition based on bacterial strain Klebsiella Oxytoca, and especially of the bacterial composition as claimed; (b) a pre-treatment process for effluent containing organic fatty substances, such as effluent from food or agricultural-food industry, comprising direct pre-treatment of effluents containing fatty substances at the exit from the plant they have originated from, and consisting of: (i) supplying effluent, as it is produced, to a homogenizing and/or conditioning tank (1), activating recycling circuit (2) between the latter and biological reactor (3), to obtain fatty substances dilution rate 0.400/h-1.500/h for their initial concentration 1 g/l; (ii) decomposing fatty substances in biological reactor (3) using a bacterial composition composed mainly of Klebsiella Oxytoca bacterial strain, or as claimed; and (iii) passing pretreated effluents containing practically no fatty substances to final treatment unit such as water purifying station; and (c) an installation for conducting the claimed process, comprising at least one homogenizing and/or conditioning tank (1), at least one biological reactor (3) of capacity adapted to the daily yield of effluents and their fatty substances concentration, linked to (1) through the recycling circuit (2), at least one oxygen control device (7) disposed in biological reactor (s) (3) and at least one unit for evacuation pre-treated effluents, outside biological reactor(s) (3).

Description

-1 -

DESCRIPTION

  The present invention relates to the field of the treatment of effluents loaded with organic fats of animal or vegetable origin as they result from industrial processes and in particular those used in the food, agro-food sector or in similar sectors. The invention relates very particularly to the field of pretreatment of said effluents and relates to a bacterial composition, a method and an installation for the pretreatment of

aforementioned effluents.

  The treatment of residual fats or lipids produced in the industry poses a number of problems. Indeed, following the health problems encountered in the treatment of animal fats (so-called "mad cow disease") and the new policies followed in terms of the environment, the requirements linked to the treatment of this type of waste have become increasingly more restrictive, as much on a technical level (upgrading of treatment facilities, improvement of

  returns ...) than on costs.

  In addition, existing treatment capacities, for example those of municipal treatment plants, are often insufficient, in particular when the fat levels present in the effluents to be treated

are important.

  To try to solve the problems linked to the treatment of fatty effluents produced in large quantities, different solutions have already

  have been considered and, for some, implemented.

  Thus, it has in particular been proposed to spread said effluents directly over large areas of agricultural land and thereby distribute the impact of their discharge on the environment, so as to achieve

  acceptable surface pollution rates.

  Another solution consists in storing said fatty materials, possibly after concentration and / or specific packaging in an approved landfill for final treatment in a specialized center.

or an incineration unit.

  Another path followed is that of fat transformation

in composts.

  -2- However, faced with ever increasing quantities of fatty effluents produced, these solutions cannot constitute satisfactory solutions in the medium or long term, in particular due to the strengthening of current anti-pollution standards which make or will make these processes non-compliant and / or economically unsustainable. It has also been proposed to adapt traditional treatment plants by incorporating grease separators (static separator or with air injection) or saponification techniques for the

  specific treatment of this type of effluent.

  However, this adaptation entails an expensive oversizing of said stations in order to be able to respond to the quantities of pollutants generated, without however allowing reliable control of the evolution of the pollution rate, and therefore of the quality of the final effluents discharged, due to the fact

  including the continuous operation of these facilities.

  Finally, several processes for the biological treatment of fats are known, in which the effluents to be treated are brought into contact with specific bio-additives and / or a suitable purifying biomass which degrades the fat by transforming it into gas and sludge. These processes

  can be implemented aerobically or anaerobically.

  However, the lactic acid bacteria involved in the methods currently used do not allow complete hydrolysis of the long chain fatty acids, which leads to a harmful overload in

  organic matter in the aeration tank.

  In addition, the bacteria currently used do not retain, by multiplying, the properties which were initially conferred on them during their creation by genetic manipulation. It is therefore necessary to make frequent and costly supplies of new bacteria to

  maintain the efficiency of the process.

  The problem posed in the present invention therefore consists in overcoming the aforementioned drawbacks and in designing a

  bacterial composition, process and installation for pre-

  treatment of effluents loaded with fat, more particularly effluents from the food or agri-food sector, constituting a more efficient solution (yield in terms of fat removed greater than 90%), inexpensive and more reliable over time , and making it possible to meet the most stringent regulatory requirements in this area

  which concerns the purified effluents discharged.

  To this end, the present invention relates to a bacterial composition for the degradation of organic fats, characterized in that it mainly comprises the bacterial strain Klebsiella Oxytoca, and the use of a bacterial composition according to the present invention for the treatment or pre-treatment of effluents loaded with organic fats, in particular effluents from industry

food or agrifood.

  The present invention also relates to a process for the pre-treatment of effluents loaded with organic fats, in particular of effluents from the food or agrifood industry, characterized in that it consists in directly pre-treating said said effluents containing said fats leaving their place of production and in that it consists in carrying out the following steps: - supplying a homogenization and / or packaging tank with effluents to be pre-treated, as and when of their production and activate a recirculation circuit between the latter and a biological reactor so as to obtain in said biological reactor a fat dilution rate inversely proportional to the concentration of fat initially present in the effluents to be pre-treated and understood between 0.400 h-1 and 1.500 h- 'for a concentration of fat contained in said effluents with pre-tr aiter entering the homogenization and / or conditioning tank of 1 g / l, - degrading said fats in said biological reactor using a bacterial composition according to the present invention, and - discharging the pretreated effluents containing practically no more fat to a final processing unit

such as a treatment plant.

  Finally, the present invention also relates to an installation for the pretreatment of effluents loaded with organic fats, in particular for the implementation of the method according to the present invention, characterized in that it is mainly constituted by at least a homogenization and / or conditioning tank, at least one biological reactor with a capacity adapted to the daily flow rate of effluents to be pretreated and to the fat concentration thereof, said 4 - biological reactor being connected to the tank (s) (s) homogenization and conditioning by a recirculation circuit, at least one device for controlled oxygen supply disposed in the biological reactor (s) and at least one discharge of the pretreated effluents, for example by overflow, outside of said biological reactor (s).

  The invention will be better understood, thanks to the description below.

  after, which relates to a preferred embodiment, given by way of nonlimiting example, and explained with reference to the appended schematic drawings, in which: FIG. 1 is a simplified block diagram of the method according to the invention, and the Figure 2 is a simplified top view of an installation

according to the present invention.

  In accordance with the present invention, the bacterial composition for the degradation of organic fats is characterized in that it mainly comprises the bacterial strain Klebsiella Oxytoca. It has been unexpectedly and surprisingly found that the selected strain is particularly effective in degrading organic fats, in particular in degrading fats of animal or vegetable origin from the food or agrifood industry. By way of nonlimiting examples of fats which can be treated with bacteria according to the present invention, mention may be made of fats obtained from cold cuts, butchers, caterers, restaurants,

  collective catering, rendering companies, slaughterhouses ...

  According to a first embodiment, the bacterial composition according to the present invention is characterized in that it further comprises the bacterial strain Serratia Odorifera and / or

Aeromonas Hydrophyla.

  Surprisingly and unexpectedly, the specific association of these bacterial strains has proven to be particularly effective and economical for the degradation of the abovementioned fats. The strains according to the invention thus make it possible to obtain excellent yields in terms of

degraded fats.

  In practice, the microorganism or microorganisms according to the invention are advantageously added in a solid lyophilized form in the middle of

  culture contained in the grease treatment reactor.

  As an indication, the average bacterial quantity contained in the composition according to the present invention is of the order of 1016 bacteria / g of solid material. During the seeding of microorganisms, an average amount of 2.1015 bacteria / m3 is necessary for good effectiveness of said microorganisms. The growth conditions of the Klebsiella Oxytoca, Serratia Odorifera and Aéromonas Hydrophyla strains were also studied. Unexpectedly and surprisingly, it has been noted that the abovementioned strains develop particularly well under aerobic conditions, a wide range of temperatures between, preferably, 15 C and 40 C, and for a wide range of pH including at both weakly acidic (pH = 5) and weakly basic (pH = 9) media, which allows easier and more efficient use of the cultures in question. The very robust nature of these bacteria also ensures good development and optimal longevity, therefore high performance and stable over time. Preferably, the bacterial composition according to the present invention is characterized in that it is composed: from 60% to 90%, preferably about 80% by weight of bacteria of the Klebsiella Oxytoca strain, from 5% to 20%, preferably about 10% by weight of bacteria of the Serratia Odorifera strain, and from 5% to 20%, preferably about 10% by weight of bacteria of the Aéromonas Hydrophyla strain, the total of the three strains

being equal to 100%.

  In this way, a mixture of bacteria is obtained which not only has very good efficiency in terms of fat breakdown (see table below) but also practical advantages for their implementation, such as for example reduced costs. , good longevity, easy conditions for cultivation, disposal, recycling, etc. The aforementioned bacterial strains initiate the breakdown of fats by cutting the ester link between glycerol and the long chains of fatty acids because they contain lipases which allow

  to operate this enzymatic cut. It follows a degradation ([-

  oxidation) of fatty acids from the free carboxylic function by decarbonation of an acyl group. This last step is also

performed by these strains.

  Thus, the bacterial composition according to the present invention can be used for the treatment or the pretreatment of effluents loaded with organic fats, in particular of effluents from industry.

food or agrifood.

  Reference is now made to FIG. 1 which illustrates, schematically, the method of the present invention. Said method is characterized in that it consists in directly pre-treating said effluents containing said fats at the outlet of their place of production and in that it consists in carrying out the following steps: - feeding a homogenization tank and / or conditioning 1 of effluents to be pre-treated, as and when they are produced and activating a recirculation circuit 2 between the latter and a biological reactor 3 so as to obtain in said biological reactor 3 a rate of dilution of the materials fat inversely proportional to the concentration of fat initially present in the effluents to be pre-treated and between 0.400 h-1 and 1.500 h- 'for a concentration of fat contained in said effluents to be pre-treated entering the tank homogenization and / or packaging 1 of 1 g / l, - degrading said fats in said biological reactor 3 using a composite bacterial ion according to the present invention, and - evacuate the pretreated effluents containing practically no more fat to a final treatment unit

such as a treatment plant.

  The method according to the present invention makes it possible to work directly on the flow of effluents rich in fats, that is to say without prior physico-chemical separation. Of course, it is also possible to work on fats which have undergone a treatment

previous physical.

  The degradation of fats by hydrolysis and oxidation is carried out thanks to the bacterial composition in accordance with the present invention. The latter is particularly effective when the intake of fatty effluents is carried out continuously. This is why, -7- the biodegradation of greases takes place directly on the raw effluent in

working on the flow.

  The effectiveness of said composition depends on the dilution rate existing in the installation. This dilution rate corresponds to the ratio of the effluent flow rate to the volume of the biological reactor 3 and depends on the

  concentration of fats initially present in the effluents with pre-

  treat. According to another advantageous characteristic of the invention, the method according to the present invention is characterized in that the dilution ratio obtained in the biological reactor 3 is inversely proportional to the concentration of fatty substances initially present in the effluents to be pre-treated and preferably between 0.528 h- 'and 1.056 h-' for a fat concentration contained in said effluents to be pre-treated entering the homogenization and / or

packaging 1 of 1 g / l.

  The dilution rate being inversely proportional to the fat concentration initially present in the effluents to be pre-treated, it suffices to divide each of the limit values of the rate ranges indicated above (given for a fat concentration of 1 g / l) by the appropriate factor to determine the ranges of dilution rates to be used for other fat concentrations. Thus, for an initial fat concentration of 0.5 g / l the dilution rate will be between 0.800 hi 'and 3,000 h-i', preferably between 1.056 h- and 2.112 h-1 while for a content initial fat content of, for example 4 g / l, said dilution rate will then be between 0.100 h- 'and 0.375 hl, preferably between 0.132 h-' and 0.264 h-l ', etc. Advantageously, the process according to the present invention is characterized in that the concentration of fatty matter in the effluents to be pre-treated entering the homogenization and / or conditioning tank 1 is less than 40 g / l, and preferably between 0.5 g / 1 and 10 g / l. Indeed, a too low fat concentration is likely to harm the good development (growth) or the maintenance in life of the cultures of micro-organisms therefore to the chemical performances and the economic profitability of the process, as well as a too strong

  Fat concentration can also inhibit bacterial growth.

  -8- During a discontinuous supply of fatty effluent to be treated, a correct degradation of the lipids (that is to say with a yield of

  around 70 to 99%) is generally obtained in 30 to 40 hours.

  In continuous mode, and as previously indicated, the dilution rate of the fats initially present in the effluents to be pre-treated must be between 0.400 hl and 1.500 hW for a concentration of fats contained in said effluents to be pre-treated entering the homogenization and / or conditioning tank 1 of 1 g / liter. Outside this range of dilution rate values, it is possible that

  lipid degrading activity decreases significantly.

  According to a variant, the effluents to be pre-treated can also be subjected to a prior screening operation 9 with a view to the separation of the solid materials possibly present in said effluents, this before the arrival of said effluents in the homogenization tank and / or conditioning 1. This measure makes it possible to limit the size of the solid particles discharged into said homogenization and / or conditioning tank 1 by trapping, for example, the solid particles

  with sections greater than 1 cm2.

  The homogenization and / or conditioning tank 1 is provided with an agitator or any other means of agitation usually used in these applications which allows good mixing and therefore good homogenization of the effluents (temperature, pH, fat concentration ...). The effluents advantageously arrive from the top in said

  tank 1, which allows the biomass to be dispersed well.

  From said homogenization and / or conditioning tank 1, the effluents are pumped at a flow rate dependent on the aforementioned dilution rate and therefore on the fat concentration, towards the biological reactor 3. The latter is equipped with a device for aeration and a pump (not shown) for activating the recirculation circuit 2 existing between said biological reactor 3 and said homogenization tank

and / or packaging 1.

  In the particularly advantageous variant shown in FIG. 2, the arrival, in the homogenization and / or conditioning tank 1, of the recirculation waters discharged by the recirculation circuit 2 is carried out by a spraying device 4 by the top. In this way, the potential formation of a layer of fat is avoided by

  surface of said homogenization and / or packaging tank 1.

  -9- The biological degradation mainly takes place in the biological reactor 3 thanks to an oxygen enrichment of the medium, for example thanks to an aeration or oxygenation device, preferably

  thanks to at least one controlled oxygen supply device 7.

  In fact, the quantity of air to be blown into the biological reactor 3 must be large enough for the development of the biomass to be able to take place but must not cause a flotation of the fats in the said biological reactor 3. The air intake is made of

  preferably by coarse bubbling.

  From the biological reactor 3, the pretreated effluents pass by overflow and flow by gravity into a decanter 5 o the decantable particles sediment. According to a preferred embodiment, the evacuation of the pretreated effluents is done via a decanter 5 on the upper part of which a floating pump 6 is provided

  for the removal of supernatant and non-settling sludge.

  The decanter 5 is preferably conical at the base and the

  outlet of the pre-treated water is also carried out by overflow.

  The following table gives examples of results obtained within the framework of the implementation of the process for effluents coming from different industrial sectors: Effluents from an Effluents from an Effluents from a fats from a delicatessen caterer poultry production animal feed

EB EPT R EBEPT R EB EPT R EB EPTR

  g / l g / 1% g / g / l% g / l g / l% g / l g / l% conc. 3.00 0.15 95 2.60 0.10 96 0.65 0.12 82 56.06 3.18 95

in mat.

fat

  COD 3.73 1.12 70 1.86 1.10 41 4.52 1.64 64 93.30 8.69 91

BOD5 1.14 0.51 55 2.45 0.82 67

  MESt 1.38 0.61 56 1.55 0.28 82 1.60 0.54 66 76.43 4.96 94 EB = Raw Water, EPT = Pre-Treated Water, R = COD Yield = Chemical Oxygen Demand 10- BOD5 = Biochemical Oxygen Demand after 5 days MESt = Total suspended matter The average residence time of the effluents in the installation according to the invention is of the order of 24 hours. To further increase the yield of the process, the supernatant and non-settling sludge can be reinjected into, or upstream from the homogenization and / or conditioning tank 1, for example via the recycling circuit 8 shown diagrammatically in the

  figure 1. The excess settling sludge is discharged.

  The present invention also relates to an installation for the pretreatment of effluents loaded with organic fats, and intended in particular, but not limited to, the implementation of the

  pre-treatment method described above.

  This installation is mainly constituted, as shown in Figure 2 of the accompanying drawings, by at least one homogenization and / or conditioning tank 1, at least one reactor

  biological 3 of capacity adapted to the daily flow of effluents to pre-

  treat and the fat concentration of the latter, said biological reactor 3 being connected to the homogenization and conditioning tank (s) 1 by a recirculation circuit 2, at least one device for controlled supply of oxygen 7 disposed in the biological reactor (s) 3 and at least one discharge of the pretreated effluents, by

  example by overflow, outside said biological reactor or reactors 3.

  For reasons of clarity, the recirculation circuit 2 has not been shown

in figure 2.

  The biological reactor 3 advantageously has a conformation facilitating the extraction of residual sludge by the settling tank 5 and making it suitable for receiving at least one controlled oxygen supply device 7 which allows, by providing a supply of massive oxygen, maintain or accelerate the development and activity of biodegradation of bacteria in order to quickly reduce biological pollution to an acceptable level for the final treatment, for example in a treatment plant. The biological reactor 3 can be placed inside a storage tank, including the controlled oxygen supply device 7, for example a fine bubble diffuser, and be provided with conventional means.

- he -

  injection of chemical and / or biological products promoting purification. It is also advantageously equipped with the usual means for analyzing and controlling the quality of the effluents before and / or after their treatment, in particular their degree of fat pollution and / or their oxygenation level. These analysis means and other technical devices (pumps, generators, valves, control panel, etc.) are

  preferably grouped together in a technical center 10.

  Said biological reactor 3 could, for example, consist of a reactor of the type of those manufactured by the applicant. The residual sludge obtained after extraction of the liquid effluents comprises, on the one hand, decantable and little biodegradable suspended matter and, on the other hand, supernatant and non-decantable sludge which can be reinjected into or upstream of the tank. homogenization and / or

  packaging 1 by an appropriate recycling circuit 8.

  The settling sludge can be purged, with a view to its storage or spreading. The final sludge can also, depending on the quantities produced and the capacity of the decanter 5, remain stored in said decanter 5 for extraction and complete cleaning.

every 1 to 2 years, for example.

  In order to eliminate large solid particles and limit the amount of material to be decanted, it can advantageously be provided that the effluents are subjected to sieving or screening 9, possibly associated with decantation, before their discharge into the homogenization and / or packaging tank 1. In this case,

  necessary equipment known per se can complete the installation.

  Advantageously, the installation according to the invention is assembled in an oval tank 11, preferably made of concrete and compartmentalized in three basins, which can be buried or semi-buried, the

  machinery being assembled in a technical center 10 placed above

above said oval tank.

  The installation according to the invention may also include at least one control and management unit for the process used, for example of the programmable automatic controller type, which automatically controls the progress of the successive stages of treatment, by being associated with

  suitable sensors and actuators.

  In the case of effluents from the food industry, for example, from an average production unit for pie, the quantities of processed fat can be of the order of one tonne of fat per day. , which corresponds to 35m3 per day of discharges at around 5 g / 1 of

fat.

  Of course, the invention is not limited to the embodiment described and shown in the accompanying drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without however leaving

  of the protection field of the invention.

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Claims (11)

  1. Bacterial composition for the degradation of organic fats, characterized in that it mainly comprises the   bacterial strain Klebsiella Oxytoca.   2. Composition according to claim 1, characterized in that it further comprises the bacterial strain Serratia Odorifera and / or Aeromonas Hydrophyla.   3. Composition according to claim 2, characterized in that it is composed: from 60% to 90%, preferably about 80% by weight of bacteria of the Klebsiella Oxytoca strain, from 5% to 20%, preferably about 10% by weight of bacteria of the Serratia Odorifera strain, and from 5% to 20%, preferably about 10% by weight of bacteria of the Aéromonas Hydrophyla strain, the total of the three strains being equal to 100%.   4. Use of a bacterial composition according to one   any of claims 1 to 3 for treatment or pretreatment   effluents loaded with organic fats, in particular effluents   from the food or agrifood industry.   5. Process for the pretreatment of effluents loaded with organic fats, in particular of effluents from the food or agro-food industry, characterized in that it consists in directly pretreating said effluents containing said fats to leaving their place of production and in that it consists in carrying out the following steps: - supplying a homogenization and / or conditioning tank (1) with effluents to be pre-treated, as and when they are produced and activate a recirculation circuit (2) between the latter and a biological reactor (3) so as to obtain in said biological reactor (3) a fat dilution rate inversely proportional to the concentration of fat initially present in the effluents to be pre-treated and between 0.400 h- and 1.500 h- 'for a concentration of fat contained in said -14- effluents to be pre-treated entering the tank homogenization and / or conditioning (1) of 1 g / l, - degrading said fats in said biological reactor (3) using a bacterial composition according to   any one of claims 1 to 3, and   - evacuate the pre-treated effluents containing practically no more fat to a final treatment unit such as a treatment plant.   6. Method according to claim 5, characterized in that the dilution rate obtained in the biological reactor (3) is inversely proportional to the concentration of fat initially present in the effluents to be pre-treated and preferably between 0.528 h- 1 and 1.056 hl for a fat concentration contained in said effluents to be pre-treated entering the homogenization and / or packaging (1) of 1 g / l.   7. Method according to any one of claims 5 or 6,   characterized in that the fat concentration of the effluents to be pre-treated entering the homogenization and / or conditioning tank (1) is less than 40 g / l, and preferably between 0.5 g / l and 10 g / l.   8. Method according to any one of claims 5 to 7,   characterized in that the arrival, in the homogenization and / or conditioning tank (1), of the recirculation waters discharged by the   recirculation (2) is carried out by a spray device (4) from above.   9. Method according to any one of claims 5 to 8,   characterized in that the evacuation of the pretreated effluents is done by means of a decanter (5) on the upper part of which a floating pump (6) is provided for the elimination of supernatant sludge and not decanted.   10. Method according to claim 9, characterized in that the supernatant and non-settling sludge is reinjected into, or upstream of   the homogenization and / or conditioning tank (1).   11. Installation for the pretreatment of effluents loaded with organic fats, in particular for the implementation of the process   according to any one of claims 5 to 10, characterized in that it   mainly consists of at least one homogenization and / or conditioning tank (1), at least one biological reactor (3) of -15 capacity adapted to the daily flow rate of effluents to be pre-treated and to the fat concentration of the latter, said biological reactor (3) being connected to the homogenization and conditioning tank (s) (1) by a recirculation circuit (2), at least one device for controlled supply of oxygen (7 ) disposed in the biological reactor (s) (3) and at least one discharge of the pretreated effluents, by   example by overflow, outside of said biological reactor (s) (3).