CH674210A5 - Culturing bacteria in anaerobic medium - to give azobacteria capable of purifying transformer oils contg. organo:chlorine cpds. - Google Patents

Abstract

A process for prodn. of bacteria in anaerobic medium comprises inoculating a liq. medium at pH 3.5-3.8 with chosen spores, culturing the spores in the liq. with introduction of glucose, yeast extract, maize flour, NaCl, MgSO4.7H20, KH2PO4 and FeSO4.7H20, maintaining the mixt. at constant temp. in a dark chamber, drying the mixt. in an ultraviolet oven, and mixing the prod. with an equal wt. of flour. USE/ADVANTAGE - Pref. the process is used for prodn. of azobacteria which are capable of purifying oils polluted with mixts. of organochlorine cpds. (PCBs) and trichlorobenzene, and esp. for purification of transformer oils to remove the toxic substances to allow re-use of the oil. This is more economical that incineration of the contaminated oils, which can cause pollution of the atmos. and which leads to simultaneous destruction of the oil. Treatment of the oil can be carried out in situ using a treatment unit mounted on a lorry or railway truck.

Description

       

  
 



   DESCRIPTION



   The present invention relates to a method for producing a bacterium, in particular an azobacterium in an anaerobic medium.



   It also relates to the use of this azobacterium.



   We already know many varieties of bacteria that are used to digest all kinds of organic substances. The use of bacteria to decompose a number of particularly toxic polluting compounds has many advantages over the pyrolysis techniques currently used. Indeed, the incineration of polluted substances such as oils containing carboxylic groups of fatty acids which, heated at temperatures above 300 C, develop substances as toxic as dioxin and furans, has the disadvantage of rejecting polluting substances in the atmosphere. Furthermore, during the incineration, the possibly reusable part of the polluted oils is also destroyed.

  Finally, the transport of polluted oils from the place of production to the place of incineration is not without danger.



   The present invention proposes to provide a remedy to these various drawbacks by developing a process for the production of a bacterium capable of digesting the polluting elements of certain oils and in particular oils polluted with pyralene from high voltage - low voltage transformers.



   The method according to the invention is characterized in that candied spores are used, in that these spores are selected in a liquid medium with a pH between 3.5 and 3.8, in that they are sown the liquid by introducing the following products: glucose, yeast extracts, corn flour, NaCl, MgSO4 7H2O, KH2PO4, FeSO4- 7H2O, in that this mixture is kept at constant temperature in a dark room, in that the mixture is dried in an oven with ultraviolet radiation, and in that flour is added with equal weight.



   The present invention will be better understood with reference to the description of a preferred embodiment.



   The seeding of the liquid containing the candied spores is preferably carried out at a temperature between 28 and 30 C. To carry out this seeding, the liquid is mixed with 1 g of glucose, 6 g of yeast extracts, 1 g of flour. corn, 4 g NaCI, 0.5 g MgSO4 7H2O, 0.5 g KH2PO4 and 1 g Fe2SO4 7H2O per liter of liquid. To ensure the multiplication of bacteria, the mixture is preferably kept in a dark room for approximately 24 hours at a temperature between 28 and 31 C.



   The substance is then dried under ultraviolet radiation for at least approximately 8 hours.



   The anaerobic atmosphere is obtained by a nitrogen atmosphere.

 

   These bacteria, called azobacteria, because they are produced in an anaerobic medium under a nitrogen atmosphere, are advantageously used to carry out the purification of oils containing pyralene, that is to say a mixture of organochlorine compounds (PCB) and trichlorobenzene. These oils generally come from electrical transformers intended to transform high voltage into low voltage.



   This use has the advantage of allowing the return of reusable oils whose dangerous polluting substances have been removed and of avoiding the discharge into the atmosphere of polluting substances from the incineration of these polluted oils. Finally, the treatment can be carried out on site, since the treatment installation can be mounted on the platform of a vehicle such as a truck or a railway wagon.


    

Claims (9)

 CLAIMS  1. Method for producing a bacterium in an anaerobic medium, Characterized in that candied spores are used, in that these spores are selected in a liquid medium with a pH between 3.5 and 3.8 , in that the liquid is sown by introducing the following products: glucose, yeast extracts, corn flour, NaCl, MgSO4 7H2O, KH2PO4, FeSO4 - 7H2O, in that this mixture is kept at constant temperature in a dark room, in that the mixture is dried in an oven with ultraviolet radiation, and in that one adds flour of equal weight.  2. Method according to claim 1, characterized in that the seeding is carried out at a temperature between 28 and 30 "C.  3. Method according to claim 1, characterized in that the mixture is kept in the dark room for approximately 24 hours at a temperature between 28 and 31 C.    4. Method according to claim 1, characterized in that the drying is carried out under ultraviolet radiation for at least approximately 8 hours.    5. Method according to claim 1, characterized in that the liquid is seeded by introducing per liter of liquid 1 g of glucose, 6 g of yeast extracts, 1 g of corn flour, 4 g of NaCl, 0 , 5 g of MgSO4- 7H2O, 0.5 g of KH2PO4 and 1 g of Fe2SO4 7H2O.  6. Method according to one of claims 1 to 5, wherein an azobacterium is produced.  7. Azobacter produced according to the method according to claim 6.  8. Use of liazobacter according to claim 7, for the purification of polluted mineral oils.  9. Use according to claim 8, for the purification of oils containing a mixture of organochlorine compounds and trichlorobenzene from electrical transformers.