WO1997020778A1 - Method for treating effluents by anaerobic fermentation to remove sulphates therefrom - Google Patents

Method for treating effluents by anaerobic fermentation to remove sulphates therefrom Download PDF

Info

Publication number
WO1997020778A1
WO1997020778A1 PCT/FR1996/001873 FR9601873W WO9720778A1 WO 1997020778 A1 WO1997020778 A1 WO 1997020778A1 FR 9601873 W FR9601873 W FR 9601873W WO 9720778 A1 WO9720778 A1 WO 9720778A1
Authority
WO
WIPO (PCT)
Prior art keywords
reactor
stripping
anaerobic fermentation
inert gas
therefrom
Prior art date
Application number
PCT/FR1996/001873
Other languages
French (fr)
Inventor
Frédéric Ehlinger
Original Assignee
Degremont
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Degremont filed Critical Degremont
Priority to AU76998/96A priority Critical patent/AU7699896A/en
Publication of WO1997020778A1 publication Critical patent/WO1997020778A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/28—Anaerobic digestion processes
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
    • C12P3/00—Preparation of elements or inorganic compounds except carbon dioxide
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel

Definitions

  • the present invention relates to a process for the treatment, by anaerobic fermentation, of waste water with a view to the elimination of the sulfates which it contains.
  • the ecosystem consists of a mixture of commensal bacterial genera, the organic materials of which constitute the food chain, which results in their gradual destruction.
  • VFA volatile fatty acids
  • the second phase corresponds to the transformation of these polycarbonated organic acids into acetic acid and it is carried out using bacteria known as acetogens which produce hydrogen and carbon dioxide.
  • the third step constitutes ia methanization during which the residual metabolites are transformed into methane by anaerobic methanogenic bacteria of two distinct species, some called hydrogenophiles using hydrogen and carbon dioxide, the others called acetoclasts, using acetic acid.
  • waste water contains sulphates in addition to organic matter, it develops in their presence a so-called sulphate-reducing flora. This produces hydrogen sulfide (H 2 S) and disturbs the functioning of the purifying ecosystem in the following way:
  • the sulphate-reducing bacteria consume part of the VFAs, to the detriment of the acetogenic bacteria, that is to say the production of acetic acid and therefore methane.
  • the hydrogen sulphide produced inhibits the functioning of the acetogens so that a fraction of the VFAs can escape degradation and remain in the residual liquid after treatment;
  • the sulphate-reducing bacteria also harm the third phase (methanogenesis) on the one hand because they consume hydrogen and carbon dioxide to the detriment of methanogenic bacteria and on the other hand, because the hydrogen sulphide produces inhibits the functioning of acetoclast bacteria.
  • EP-A-241 999 a methane fermentation is described by successive passages of the effluent in two reactors with fixed culture.
  • the acidification takes place in the first reactor and is coupled with a biological reduction of the sulfates.
  • the effluent leaving the first reactor is freed from hydrogen sulphide by stripping by means of an inert gas with respect to the biological process in an intermediate structure or stripping column, before being admitted into the second reactor.
  • This known solution requires a regulation of the pH between 6.5 and 6.7, so as to promote the sulphate reduction and the stripping of the H 2 S outside the reactor, which constitutes an expensive and difficult operation. optimize in an industrial structure, in particular when sulfuric acid is used for this purpose, which further increases the sulphate content.
  • EP-A-0 418 121 describes a process for the treatment by anaerobic fermentation of waste water which consists in using a single free culture reactor, infinitely mixed, in which is introduced into the biomass that it contains a neutral gas intended displacement of the H 2 S formed.
  • this process does not make it possible to solve the problem mentioned above, in particular as regards the absence of methane formation.
  • the present invention proposes to provide a process for anaerobic fermentation of sulfates by a free bacterial culture, this process being implemented in a specific single reactor where the hydrolysis step takes place. -acetogenesis in the absence of oxygen and without the formation of methane.
  • the invention relates to a process for treating, by anaerobic fermentation, waste water, with a view to eliminating the sulphates which they contain, and without methanization, with stripping of the hydrogen sulphide produced, by means of an inert gas characterized in that this process is carried out in a single reactor, of the free culture type, infinitely mixed, that is to say with integral mixture in which stripping takes place directly with using an exogenous inert gas introduced into the biomass, the residence time of the effluent in the reactor being between 2 and 48 hours and the pH of the medium self-regulating at 6.7 ⁇ 0, 2.
  • the neutral gas used for stripping can be nitrogen, helium, or argon.
  • the reactions of acidogenesis and of sulfato-reductions are organized simultaneously.
  • the anaerobic fermentation of sulfates in this reactor by a free bacterial culture is characterized by the fact that it produces absolutely no methane.
  • the absence of methane results from the absence of methanogenic bacteria.
  • the residence time of the effluent in the reactor according to the present invention between 2 and 48 hours is too short to allow the development of such methanogenic bacteria.
  • such bacteria do not have the possibility of being fixed on a support since the reactor according to the invention is of the free culture type.
  • the process according to the invention can be implemented by means, as shown in the single figure of the appended drawing, of a free culture reactor, infinitely mixed, that is to say of the fully mixed type, consisting of an enclosure 1 in which the effluent to be treated is brought into the reactor within the biomass 4 via a pipe 2 and from which it leaves, purified, by a pipe 3
  • the biomass is in the form of a free culture and this is constantly stirred by a suitable member 8, driven by a motor 9
  • the stripping of the hydrogen sulphide produced in the reactor is carried out by an injection of inert gas (nitrogen, helium or argon) directly into the reactor within the biomass.
  • inert gas nitrogen, helium or argon
  • This characteristic makes it possible to cause a rise in pH which, on the one hand promotes the displacement of H 2 S from the liquid phase towards the gas phase and, on the other hand, promotes the activity of the sulfato-reduct ⁇ ces bacteria and therefore elimination of sulfates.
  • the neutral gas is introduced into the enclosure 1 of the reactor, within the biomass 4, using a pipe 5
  • the departure of the H 2 S entrained by the inert gas via the outlet 6 makes it possible to reduce the content of dissolved sulphides up to values of the order of 100 mg / l.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Microbiology (AREA)
  • Zoology (AREA)
  • Wood Science & Technology (AREA)
  • Bioinformatics & Cheminformatics (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • Biotechnology (AREA)
  • General Engineering & Computer Science (AREA)
  • General Health & Medical Sciences (AREA)
  • Genetics & Genomics (AREA)
  • General Chemical & Material Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Preparation Of Compounds By Using Micro-Organisms (AREA)
  • Apparatus Associated With Microorganisms And Enzymes (AREA)
  • Treatment Of Sludge (AREA)
  • Physical Water Treatments (AREA)

Abstract

A method for treating effluents by anaerobic fermentation to remove sulphates therefrom without generating methane, wherein the hydrogen sulphide generated is stripped using an inert gas, characterised in that it is implemented in a single infinitely mixed, i.e. completely mixed free-culture reactor in which stripping is performed directly using an exogenous inert gas delivered into the biomass, and the residence time of the effluent in the reactor is from 2 to 48 hours while the pH of the medium is self-adjusted to 6.7 ± 0.2.

Description

Procédé de traitement par fermentation anaérobie d'eaux résiduaires pour l'élimination des sulfates Process for the treatment by anaerobic fermentation of waste water for the elimination of sulfates
La présente invention concerne un procédé de traitement, par fermentation anaérobie, d'eaux résiduaires en vue de l'élimination des sulfates qu'elles contiennentThe present invention relates to a process for the treatment, by anaerobic fermentation, of waste water with a view to the elimination of the sulfates which it contains.
On sait que la dégradation de la matière organique, présente dans les eaux résiduaires par digestion anaérobie, est réalisée par un écosystème complexe ayant pour phase uitime une fermentation se traduisant par la production de méthane Le rendement de l'épuration a laquelle sont ainsi soumises ces eaux dépend donc en particulier de l'efficacité de cette dernière phaseIt is known that the degradation of organic matter, present in waste water by anaerobic digestion, is carried out by a complex ecosystem having as fermentation phase resulting in the production of methane The yield of the purification to which these are thus subjected waters therefore depends in particular on the effectiveness of this last phase
L'écosystème consiste en un mélange de genres bactériens commensaux, dont les matières organiques constituent la chaîne alimentaire, ce qui se traduit par leur destruction progressive On peut distinguer trois phases séparées, généralement simultanées dans les appareils de traitement ou coexistent a la fois les différents genres microbiens et des matières à différents stades de leur dégradation Ces trois phases sont respectivement l'hydrolyse-acidogenese, l'acetogenese, et la methanogénèseThe ecosystem consists of a mixture of commensal bacterial genera, the organic materials of which constitute the food chain, which results in their gradual destruction. We can distinguish three separate phases, generally simultaneous in the treatment devices where the different coexist at the same time. microbial genera and materials at different stages of their degradation These three phases are respectively hydrolysis-acidogenesis, acetogenesis, and methanogenesis
Lors de la première phase réalisée par des bactéries extrêmement diverses mesophiles ou thermophiles, anaérobies strictes ou facultatives, les molécules complexes sont hydrolysees en molécules plus simples dénommées acides gras volatils (ou AGV) tels que l'acide lactique, l'acide acétique, l'acide propionique, l'acide butyrique et en composés gazeux tels que l'hydrogène et le gaz carboniqueDuring the first phase carried out by extremely diverse mesophilic or thermophilic bacteria, strict or optional anaerobes, the complex molecules are hydrolyzed into simpler molecules called volatile fatty acids (VFA) such as lactic acid, acetic acid, l propionic acid, butyric acid and gaseous compounds such as hydrogen and carbon dioxide
La deuxième phase correspond à la transformation de ces acides organiques polycarbonés en acide acétique et elle est réalisée a l'aide de bactéries dites acetogenes qui produisent de l'hydrogène et du gaz carbonique Enfin, la troisième étape constitue ia méthanisation au cours de laquelle les métabolites résiduels sont transformés en méthane par des bactéries méthanogènes anaérobies de deux espèces distinctes, les unes dites hydrogénophiles utilisant l'hydrogène et le gaz carbonique, les autres dites acétoclastes, utilisant l'acide acétique.The second phase corresponds to the transformation of these polycarbonated organic acids into acetic acid and it is carried out using bacteria known as acetogens which produce hydrogen and carbon dioxide. Finally, the third step constitutes ia methanization during which the residual metabolites are transformed into methane by anaerobic methanogenic bacteria of two distinct species, some called hydrogenophiles using hydrogen and carbon dioxide, the others called acetoclasts, using acetic acid.
Lorsque, comme c'est souvent le cas, les eaux résiduaires contiennent des sulfates en plus des matières organiques, il se développe en leur présence une flore dite sulfato-réductrice. Celle-ci produit de l'hydrogène sulfuré (H2S) et perturbe le fonctionnement de l'écosystème épuratoire de la façon suivante :When, as is often the case, waste water contains sulphates in addition to organic matter, it develops in their presence a so-called sulphate-reducing flora. This produces hydrogen sulfide (H 2 S) and disturbs the functioning of the purifying ecosystem in the following way:
- au cours de la deuxième phase, (l'acétogénèse) les bactéries sulfato-réductnces consomment une partie des AGV, au détriment des bactéries acétogènes, c'est-à- dire de la production d'acide acétique et donc de méthane. De plus, l'hydrogène sulfuré produit inhibe le fonctionnement des acétogènes si bien qu'une fraction des AGV peut échapper à la dégradation et subsister dans le liquide résiduaire à l'issue du traitement ;- during the second phase, (acetogenesis) the sulphate-reducing bacteria consume part of the VFAs, to the detriment of the acetogenic bacteria, that is to say the production of acetic acid and therefore methane. In addition, the hydrogen sulphide produced inhibits the functioning of the acetogens so that a fraction of the VFAs can escape degradation and remain in the residual liquid after treatment;
- les bactéries sulfato-réductrices nuisent également à la troisième phase (la méthanogénèse) d'une part parce qu'elles consomment l'hydrogène et le gaz carbonique au préjudice des bactéries méthanogènes et d'autre part, parce que l'hydrogène sulfuré produit inhibe le fonctionnement des bactéries acétoclastes.- the sulphate-reducing bacteria also harm the third phase (methanogenesis) on the one hand because they consume hydrogen and carbon dioxide to the detriment of methanogenic bacteria and on the other hand, because the hydrogen sulphide produces inhibits the functioning of acetoclast bacteria.
La présence de sulfates dans des effluents destinés à être épurés par fermentation méthanique risque donc de limiter les performances des réacteurs biologiques dans lesquels s'effectue cette fermentation.The presence of sulfates in effluents intended to be purified by methane fermentation therefore risks limiting the performance of the biological reactors in which this fermentation takes place.
Il est possible d'éviter les phénomènes d'inhibition en isolant physiquement des autres phases, la phase la plus sensible c'est-à-dire celle de formation du méthane (la méthanogénèse). Dans ce but, on a été amené à créer dans deux réacteurs séparés les conditions biologiques nécessaires à la réalisation des différentes étapes du processus. Dans le second réacteur, l'effluent ainsi modifié subit d'autres modifications : en particulier, on peut y favoriser la fermentation méthanique.It is possible to avoid inhibition phenomena by physically isolating from the other phases, the most sensitive phase, that is to say that of methane formation (methanogenesis). To this end, we have been led to create in two separate reactors the biological conditions necessary for carrying out the different stages of the process. In the second reactor, the effluent thus modified undergoes other modifications: in particular, it is possible to promote methane fermentation there.
Dans EP-A-241 999, est décrite une fermentation méthanique par passages successifs de l'effluent dans deux réacteurs à culture fixée. L'acidification se déroule dans le premier réacteur et elle est couplée à une réduction biologique des sulfates. L'effluent sortant du premier réacteur est débarrassé de l'hydrogène sulfuré par strippage au moyen d'un gaz inerte vis-à-vis du processus biologique dans un ouvrage intermédiaire ou colonne de strippage, avant d'être admis dans le second réacteur.In EP-A-241 999, a methane fermentation is described by successive passages of the effluent in two reactors with fixed culture. The acidification takes place in the first reactor and is coupled with a biological reduction of the sulfates. The effluent leaving the first reactor is freed from hydrogen sulphide by stripping by means of an inert gas with respect to the biological process in an intermediate structure or stripping column, before being admitted into the second reactor.
Cette solution connue nécessite une régulation du pH entre 6,5 et 6,7, de façon à favoriser la sulfato-réduction et le strippage de I' H2S à l'extérieur du réacteur, ce qui constitue une opération coûteuse et difficile à optimiser dans un ouvrage industriel, en particulier dans le cas où l'on utilise dans ce but de l'acide sulfurique qui accroît encore ia teneur en sulfates.This known solution requires a regulation of the pH between 6.5 and 6.7, so as to promote the sulphate reduction and the stripping of the H 2 S outside the reactor, which constitutes an expensive and difficult operation. optimize in an industrial structure, in particular when sulfuric acid is used for this purpose, which further increases the sulphate content.
EP-A-0 418 121 décrit un procédé de traitement par fermentation anaérobie d'eaux résiduaires qui consiste à utiliser un réacteur unique à culture libre, infiniment mélangé, dans lequel on introduit au sein de ia biomasse qu'il contient un gaz neutre destiné au déplacement de l'H2S formé. L'expérience montre que ce procédé ne permet pas de résoudre le problème mentionné ci-dessus notamment en ce qui concerne l'absence de formation de méthane.EP-A-0 418 121 describes a process for the treatment by anaerobic fermentation of waste water which consists in using a single free culture reactor, infinitely mixed, in which is introduced into the biomass that it contains a neutral gas intended displacement of the H 2 S formed. Experience has shown that this process does not make it possible to solve the problem mentioned above, in particular as regards the absence of methane formation.
Partant de cet état de la technique, la présente invention se propose d'apporter un procédé de fermentation anaérobie des sulfates par une culture bactérienne libre, ce procédé étant mis en oeuvre dans un réacteur unique spécifique où s'effectue l'étape d'hydrolyse-acétogénèse en absence d'oxygène et sans formation de méthane.Based on this state of the art, the present invention proposes to provide a process for anaerobic fermentation of sulfates by a free bacterial culture, this process being implemented in a specific single reactor where the hydrolysis step takes place. -acetogenesis in the absence of oxygen and without the formation of methane.
Dans ce but, l'invention concerne un procédé de traitement, par fermentation anaérobie, d'eaux résiduaires, en vue de l'élimination des sulfates qu'elles contiennent, et sans méthanisation, avec strippage de l'hydrogène sulfuré produit, au moyen d'un gaz inerte caractérisé en ce que ce procédé est mis en oeuvre dans un réacteur unique, du type à culture libre, infiniment mélangé c'est-à-dire à mélange intégral dans lequel s'effectue directement le strippage à l'aide d'un gaz inerte exogène introduit au sein de la biomasse, le temps de séjour de l'effluent dans le réacteur étant compris entre 2 et 48 heures et le pH du milieu s'auto-régulant à 6,7 ± 0,2.To this end, the invention relates to a process for treating, by anaerobic fermentation, waste water, with a view to eliminating the sulphates which they contain, and without methanization, with stripping of the hydrogen sulphide produced, by means of an inert gas characterized in that this process is carried out in a single reactor, of the free culture type, infinitely mixed, that is to say with integral mixture in which stripping takes place directly with using an exogenous inert gas introduced into the biomass, the residence time of the effluent in the reactor being between 2 and 48 hours and the pH of the medium self-regulating at 6.7 ± 0, 2.
Selon l'invention, le gaz neutre utilisé pour le strippage peut être de l'azote, de l'hélium, ou de l'argon.According to the invention, the neutral gas used for stripping can be nitrogen, helium, or argon.
Comme on le comprend, dans le réacteur selon la présente invention, on organise simultanément les réactions d'acidogénèse et de sulfato-réductions. La fermentation anaérobie des sulfates dans ce réacteur par une culture bactérienne libre est caractérisée par le fait qu'elle ne produit absolument pas de méthane. L'absence de méthane résulte de l'absence de bactéries méthanogènes. En effet, le temps de séjour de l'effluent dans le réacteur selon la présente invention, compris entre 2 et 48 heures est trop court pour permettre le développement de telles bactéries méthanogènes. Par ailleurs, de telles bactéries n'ont pas la possibilité de se fixer sur un support étant donné que le réacteur selon l'invention est du type à culture libre.As will be understood, in the reactor according to the present invention, the reactions of acidogenesis and of sulfato-reductions are organized simultaneously. The anaerobic fermentation of sulfates in this reactor by a free bacterial culture is characterized by the fact that it produces absolutely no methane. The absence of methane results from the absence of methanogenic bacteria. Indeed, the residence time of the effluent in the reactor according to the present invention, between 2 and 48 hours is too short to allow the development of such methanogenic bacteria. Furthermore, such bacteria do not have the possibility of being fixed on a support since the reactor according to the invention is of the free culture type.
Les essais auxquels s'est livré la demanderesse sur un réacteur pilote selon la présente invention ont donné lieu à un gaz dont la composition est la suivante :The tests carried out by the applicant on a pilot reactor according to the present invention gave rise to a gas whose composition is as follows:
N2 = 60% CO2 = 30% H2S = 10%N 2 = 60% CO 2 = 30% H 2 S = 10%
Cette composition démontre clairement l'absence d'une phase de méthanisation dans le réacteur selon la présente invention.This composition clearly demonstrates the absence of a methanization phase in the reactor according to the present invention.
Par ailleurs, on a constaté de façon absolument surprenante qu'en menant, selon l'invention, la fermentation anaérobie (Acidogénèse-sulfato-réduction) avec déplacement de IΗ2S formé au moyen d'un gaz inerte exogène (azote, hélium ou argon) introduit dans le réacteur au sein de la biomasse, le pH du milieu s'établissait et s'auto-regulait a 6,7 ± 0,2 et que le taux de réduction des sulfates s'établissait aux environs de 80% alors que, en mettant en oeuvre les procédés connus, le pH variait dans des limites importantes, ce qui nécessitait des mesures coûteuses de contrôle de pH dans ie reacteur, par exemple des additions de soude ou de chaux, et le taux de conversion des sulfates ne dépassait pas 50%Furthermore, it has been found in an absolutely surprising manner that by carrying out, according to the invention, anaerobic fermentation (Acidogenesis-sulfato-reduction) with displacement of IΗ 2 S formed by means of an exogenous inert gas (nitrogen, helium or argon) introduced into the reactor within the biomass, the pH of the medium was established and self-regulated at 6.7 ± 0.2 and that the reduction rate of sulfates was established around 80% then that, by implementing known methods, the pH varied within wide limits, which required costly pH control measures in the reactor, for example additions of soda or lime, and the conversion rate of the sulfates did not not exceed 50%
On peut mettre en oeuvre le procédé selon l'invention au moyen, comme le montre la figure unique du dessin annexé, d'un réacteur a culture libre, infiniment mélange, c'est-à-dire du type à mélange intégral, constitué par une enceinte 1 dans laquelle l'effluent à traiter est amené dans le réacteur au sein de la biomasse 4 par l'intermédiaire d'une canalisation 2 et de laquelle il sort, épuré, par une canalisation 3The process according to the invention can be implemented by means, as shown in the single figure of the appended drawing, of a free culture reactor, infinitely mixed, that is to say of the fully mixed type, consisting of an enclosure 1 in which the effluent to be treated is brought into the reactor within the biomass 4 via a pipe 2 and from which it leaves, purified, by a pipe 3
La biomasse se présente sous la forme d'une culture libre et celle-ci est constamment brassée par un organe 8 adapté, mue par un moteur 9The biomass is in the form of a free culture and this is constantly stirred by a suitable member 8, driven by a motor 9
Selon l'invention, le strippage de l'hydrogène sulfuré produit dans le réacteur est effectué par une injection de gaz inerte (Azote, Hélium ou argon) directement dans le réacteur au sein de la biomasse. Cette caractéristique permet de provoquer une remontée du pH qui, d'une part favorise le déplacement de l'H2S de ia phase liquide vers la phase gazeuse et, d'autre part, favorise l'activité des bactéries sulfato- réductπces et donc l'élimination des sulfates. Comme on le voit sur le dessin, le gaz neutre est introduit dans l'enceinte 1 du réacteur, au sein de la biomasse 4, à l'aide d'une canalisation 5 Le départ de l'H2S entraîné par le gaz inerte par l'intermédiaire de l'évacuation 6 permet de diminuer la teneur en sulfures dissous jusqu'à des valeurs de l'ordre de 100 mg/l.According to the invention, the stripping of the hydrogen sulphide produced in the reactor is carried out by an injection of inert gas (nitrogen, helium or argon) directly into the reactor within the biomass. This characteristic makes it possible to cause a rise in pH which, on the one hand promotes the displacement of H 2 S from the liquid phase towards the gas phase and, on the other hand, promotes the activity of the sulfato-reductπces bacteria and therefore elimination of sulfates. As can be seen in the drawing, the neutral gas is introduced into the enclosure 1 of the reactor, within the biomass 4, using a pipe 5 The departure of the H 2 S entrained by the inert gas via the outlet 6 makes it possible to reduce the content of dissolved sulphides up to values of the order of 100 mg / l.
Il demeure bien entendu que l'invention n'est pas limitée aux différents modes de mise en oeuvre décrits ci-dessus mais qu'elle en englobe toutes les variantes It remains to be understood that the invention is not limited to the various embodiments described above but that it encompasses all variants thereof.

Claims

REVENDICATIONS
1 - Procédé de traitement, par fermentation anaérobie, d'eaux résiduaires en vue de l'élimination des sulfates qu'elles contiennent, sans méthanisation, avec strippage de l'hydrogène sulfuré produit, au moyen d'un gaz inerte caractérisé en ce qu'il est mis en oeuvre dans un réacteur unique, du type à culture libre, infiniment mélangé, c'est-à-dire à mélange intégral, dans lequel s'effectue directement le strippage à l'aide d'un gaz inerte exogène introduit au sein de ia biomasse, le temps de séjour de l'effluent dans ce réacteur étant compris entre 2 et 48 heures et le pH du milieu s'auto-réguiant à 6,7 ± 0,21 - Process for the treatment, by anaerobic fermentation, of waste water with a view to the elimination of the sulphates which they contain, without methanization, with stripping of the hydrogen sulphide produced, by means of an inert gas characterized in that '' it is implemented in a single reactor, of the free culture type, infinitely mixed, that is to say with integral mixture, in which stripping takes place directly using an exogenous inert gas introduced within the biomass, the residence time of the effluent in this reactor being between 2 and 48 hours and the pH of the medium self-regulating at 6.7 ± 0.2
2 - Procédé selon la revendication 1 caractérisé en ce que le gaz neutre utilisé pour le strippage est choisi parmi les gaz suivants azote, hélium et l'argon 2 - Process according to claim 1 characterized in that the neutral gas used for stripping is chosen from the following gases nitrogen, helium and argon
PCT/FR1996/001873 1995-12-04 1996-11-26 Method for treating effluents by anaerobic fermentation to remove sulphates therefrom WO1997020778A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU76998/96A AU7699896A (en) 1995-12-04 1996-11-26 Method for treating effluents by anaerobic fermentation to remove sulphates therefrom

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR95/14315 1995-12-04
FR9514315A FR2741874B1 (en) 1995-12-04 1995-12-04 ANAEROBIC FERMENTATION TREATMENT PROCESS FOR WASTEWATER FOR SULPHATE REMOVAL

Publications (1)

Publication Number Publication Date
WO1997020778A1 true WO1997020778A1 (en) 1997-06-12

Family

ID=9485126

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FR1996/001873 WO1997020778A1 (en) 1995-12-04 1996-11-26 Method for treating effluents by anaerobic fermentation to remove sulphates therefrom

Country Status (3)

Country Link
AU (1) AU7699896A (en)
FR (1) FR2741874B1 (en)
WO (1) WO1997020778A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6852305B2 (en) * 1998-11-16 2005-02-08 Paques Bio Systems B.V. Process for the production of hydrogen sulphide from elemental sulphur and use thereof in heavy metal recovery

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1127850A1 (en) * 2000-02-25 2001-08-29 Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno Removal of sulfur compounds from wastewater

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2461684A1 (en) * 1979-07-23 1981-02-06 Degremont Sa Purificn. of organically polluted water contg. sulphate(s) - using anaerobic bacteria with sulphide(s) removed by gas entrainment
EP0241999A1 (en) * 1986-04-16 1987-10-21 Biothane Systems International B.V. Anaerobic purification of waste water containing sulphate and organic material
EP0331806A1 (en) * 1988-03-09 1989-09-13 Passavant-Werke Ag Process for the anaerobic purification of waste and process water
EP0418121A1 (en) * 1989-09-14 1991-03-20 Degremont S.A. Process for elimination of organic substances and sulphates from waste waters by means of anaerobic fermentation
JPH06246294A (en) * 1993-02-25 1994-09-06 Toshiba Corp Waste water treatment device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2461684A1 (en) * 1979-07-23 1981-02-06 Degremont Sa Purificn. of organically polluted water contg. sulphate(s) - using anaerobic bacteria with sulphide(s) removed by gas entrainment
EP0241999A1 (en) * 1986-04-16 1987-10-21 Biothane Systems International B.V. Anaerobic purification of waste water containing sulphate and organic material
EP0331806A1 (en) * 1988-03-09 1989-09-13 Passavant-Werke Ag Process for the anaerobic purification of waste and process water
EP0418121A1 (en) * 1989-09-14 1991-03-20 Degremont S.A. Process for elimination of organic substances and sulphates from waste waters by means of anaerobic fermentation
JPH06246294A (en) * 1993-02-25 1994-09-06 Toshiba Corp Waste water treatment device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 018, no. 639 (C - 1282) 6 December 1994 (1994-12-06) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6852305B2 (en) * 1998-11-16 2005-02-08 Paques Bio Systems B.V. Process for the production of hydrogen sulphide from elemental sulphur and use thereof in heavy metal recovery

Also Published As

Publication number Publication date
AU7699896A (en) 1997-06-27
FR2741874B1 (en) 1998-02-20
FR2741874A1 (en) 1997-06-06

Similar Documents

Publication Publication Date Title
EP0241999B1 (en) Anaerobic purification of waste water containing sulphate and organic material
JPS6332520B2 (en)
Vossoughi et al. Performance of anaerobic baffled reactor treating synthetic wastewater influenced by decreasing COD/SO4 ratios
KR100196556B1 (en) Process for the treatment of water containing sulphur compounds
Cervantes et al. Nitrogen removal from wastewaters at low C/N ratios with ammonium and acetate as electron donors
Colleran et al. Mesophilic and thermophilic anaerobic digestion of sulphate-containing wastewaters
CN1238711A (en) Process for biological removal of sulphide
Gorris et al. Inhibition of propionate degradation by acetate in methanogenic fluidized bed reactors
BE1004311A3 (en) Method and installation for the treatment of waste water, waste water especially urban.
FR2586411A1 (en) METHOD AND DEVICE FOR REDUCING THE TOXICITY OF SULPHITES
CN1228118A (en) Sulphur reducing bacterium and its use in biological desulphurisation processes
CA2024993C (en) Residual water anaerobic fermentation treatment process for sulfates and organic materials suppression
CA2401371A1 (en) Removal of sulfur compounds from wastewater
EP0925258B1 (en) Method for purifying carbon-containing pollution and denitrifying waste water in oxygenic medium
Percheron et al. Nitrate and nitrite reduction of a sulphide‐rich environment
EP2018417B1 (en) Novel microorganism for treating wastewater and corresponding method
WO2014116186A1 (en) A process for mitigating sulfate impact on and enhancing methane production in anaerobic systems
FR2720736A1 (en) Process for the treatment of liquid effluents by activated sludge.
Wang et al. Metagenomic analysis of microbial community and metabolic pathway of simultaneous sulfide and nitrite removal process exposed to divergent hydraulic retention times
Zhou et al. Competition between methanogenesis and sulfidogenesis in anaerobic wastewater treatment
WO1997020778A1 (en) Method for treating effluents by anaerobic fermentation to remove sulphates therefrom
EP0262107A2 (en) Anaerobic process
EP1630139A1 (en) Process for the biological denitrification of ammonium containing wastewater
Van Houten et al. Biological sulphate reduction with synthesis gas: microbiology and technology
JPS603876B2 (en) Method for treating wastewater containing nitrogen components

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TR TT UA UG US UZ VN AM AZ BY KG KZ MD RU TJ TM

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): KE LS MW SD SZ UG AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: JP

Ref document number: 97521027

Format of ref document f/p: F

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase