WO2013000927A1 - Procédé de traitement d'une boue ou d'une autre matière organique - Google Patents

Procédé de traitement d'une boue ou d'une autre matière organique Download PDF

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Publication number
WO2013000927A1
WO2013000927A1 PCT/EP2012/062385 EP2012062385W WO2013000927A1 WO 2013000927 A1 WO2013000927 A1 WO 2013000927A1 EP 2012062385 W EP2012062385 W EP 2012062385W WO 2013000927 A1 WO2013000927 A1 WO 2013000927A1
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Prior art keywords
enzyme
treatment
organic material
sludge
biogas
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PCT/EP2012/062385
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English (en)
Inventor
Hendrik Louis Bijl
Vincent Pascal Pelenc
Monika Wolf
Wolfgang Speter
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Dsm Ip Assets B.V.
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Application filed by Dsm Ip Assets B.V. filed Critical Dsm Ip Assets B.V.
Publication of WO2013000927A1 publication Critical patent/WO2013000927A1/fr
Priority to PCT/EP2013/063306 priority Critical patent/WO2014001349A1/fr
Priority to EP13730910.0A priority patent/EP2864490A1/fr
Priority to US14/410,311 priority patent/US20150337337A1/en
Priority to CN201380033601.6A priority patent/CN104411829A/zh

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    • 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
    • C12P7/00—Preparation of oxygen-containing organic compounds
    • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
    • C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
    • C12P7/06—Ethanol, i.e. non-beverage
    • C12P7/08—Ethanol, i.e. non-beverage produced as by-product or from waste or cellulosic material substrate
    • 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
    • C12P5/00—Preparation of hydrocarbons or halogenated hydrocarbons
    • C12P5/02—Preparation of hydrocarbons or halogenated hydrocarbons acyclic
    • 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
    • Y02E50/10—Biofuels, e.g. bio-diesel
    • 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 of sludge or other organic material.
  • biogas via the anaerobic digestion of organic material such as sludge is a rapidly growing source of renewable energy.
  • the process is complex; a combined action of several biotechnological processes determines the stability, efficiency and yield of the biogas produced.
  • An optimal process design is still under active research done at laboratory and pilot plants. After for example an alkaline treatment, sludge can be used as feed for the biogas production due to their high yield potential.
  • Digesting systems are often divided in one-stage and two-stage digesters.
  • one-stage digesters all the microbiological phases of the anaerobic digestion takes place in one tank or fermenter.
  • two-stage digesters the hydrolysis and acidification will take place in the first reactor and acetogenesis and methanogenesis occurs in the second reactor.
  • the two phase concept is often chosen for optimisation of the digestion process in order to produce more methane.
  • Both one-stage and two-stage processes have in common that all the phases of the anaerobic digestion are a microbiological process, involving the presence of suitable consortia of microorganisms.
  • CSTR continuously stirred tank reactor
  • SBR sequential batch reactor
  • Anaerobic membrane bioreactor AnMBR
  • UASB upflow anaerobic sludge blanket
  • EGSB expended granular sludge bed
  • IC Internal Circulation reactor
  • the present invention provides an improved process for the treatment of sludge or other organic material.
  • sludge Preferably sludge, more preferably sludge from an aerobic purification or fermentation process, is treated.
  • the present invention provides an enzyme composition for use in the treatment of sludge and other organic material.
  • the treatment or process can be a two-stage process whereby only the second stage is a microbiological digestion.
  • the organic material In the first stage the organic material is heat treated to prevent growth of microorganisms present and the heat-treated sludge or other organic material is enzymatically treated.
  • the effluent of the first stage is separated in a liquid and a solid fraction.
  • the liquid fraction can be fed to the next stage to produce for example ethanol and biogas.
  • the thermal and enzymatic treatment allows a control and an optimization of this step (first phase) which cannot be realized in an active microbiological environment.
  • the enzymes used in the enzymatic treatment are a combination of a lysing enzyme, a protease, a lipase and a cellulase, and optionally amylase.
  • the process of the invention makes lower overall retention times possible without loss of gas yield compared to prior art processes.
  • Fig. 1 shows the variations in sequence and combinations of lytic enzymes to reduce the number of microorganisms in pig manure. Detailed description of the invention
  • biogas is meant the product produced by the anaerobic digestion or fermentation of biodegradable materials.
  • Biogas comprises primarily methane and carbon dioxide and may have small amounts of hydrogen sulphide, moisture and siloxanes. In special cases hydrogen is the targeted product.
  • organic or biological material is meant matter that has come from a once- living or still-living organism; is capable of decay, or the product of decay.
  • the organic material is microbial material such as sludge or biomass from purification, fermentation or digestion processes. Especially bacterial sludge from an aerobic purification process or bacterial biomass from an aerobic d igestion can be advantageously treated according to the present invention.
  • sludge or activated sludge is meant the solid waste or solid waste product or solid biomass of waste water or sewage treatment.
  • This solid waste product consists mainly of bacteria.
  • sludge of an aerobic purification step or system is used.
  • Suitable organic waste streams that can be used in the present process are fermentation broths or fractions thereof from industrial fermentation industries.
  • Another suitable organic waste stream is manure such as cow, pig, goat or horse manure.
  • organic matter content of the organic material is meant the dry matter content of the organic material minus ash.
  • COD Chemical Oxygen Demand
  • ISO 6060 (1989) ISO 6060 (1989).
  • the present invention provides a process for the treatment of sludge or other organic material which comprises:
  • the liquid fraction may advantageously be fed to the next stage to produce for example ethanol and biogas. So the process of the invention may comprise the additional and subsequent steps of
  • the process of the invention may comprise the additional and subsequent steps of
  • the process of the invention is capable to treat all kind of digestible organic material such as sludge or other organic material, preferably bacterial sludge or other bacterial organic waste.
  • bacterial sludge from an aerobic purification process or bacterial biomass from an aerobic digestion can be treated according to the present invention.
  • the bacteria of these aerobic processes are found to be enzymatically digestible.
  • the cell walls of these bacteria are found to be degradable by lytic enzymes optionally in combination with the pretreatment of the sludge or biomass as described herein.
  • the separation of the enzymatic step and the optional microbiological digestion provides for an optimal control and selection of conditions to treat the organic material.
  • fractions of sludge or mixes of several kinds of sludges or fractions thereof can be used in the process of the invention.
  • sludge may be mixed or combined with other organic material or substrates like grass or manure.
  • other microbial material such as biomass originating from for example yeast or fungal fermentation industries such as breweries or algae biomass from the cultivation of algae, can be used in the process of the present invention.
  • the present process is found to be very useful for N-enriched substrates or digestible organic material.
  • the sludge or other organic material is preferably heat-treated or pasteurized at a temperature of 65 to 120 °C, more preferably at 65 to 95 °C for a suitable time.
  • Pasteurization is a process of heating the organic material to a specific temperature for a definite length of time in a humid environment. For example pasteurization at 72 °C for 30 seconds is sufficient. For example 1 hour at 120 °C gives the same results as 4 hours at 90 °C with respect to the CFU count (see below). In general high temperatures may result in more protein denaturation as well as occurrence of toxic compounds. In general if the pasteurization time is longer, the pasteurization temperature can be lower. The water content at pasteurization should be sufficient to enable pasteurization effect.
  • the water content will be between 30 and 95 wt%, preferably between 50 and 90 wt%.
  • This process slows microbial growth in the organic material.
  • Pasteurization or heat- treatment is not intended to kill all micro-organisms in the organic material. Instead pasteurization or heat-treatment aims to reduce the number of viable microorganisms so they are unlikely to substantially produce biogas or other fermentation products like organic acids and alcohols in the first stage (or first step or first phase or enzyme treatment) of the process.
  • the first stage less than 2 %, preferably less than 1 %, of the total of biogas is formed from the possible biogas formed in an UASB biogas reactor when such a reactor would be applied for the effluent from this enzyme treatment step.
  • the CFU count is in general lower than 10 6 , preferably less than 10 5 , even more preferably less than 10 4 and most preferably less than 10 3 CFU/ml in the organic material present.
  • colony-forming unit CFU or cfu
  • CFU colony-forming unit
  • the pasteurization step also facilitates the use of enzymes or enzyme mixtures directly originating from harvested enzyme production fermentations.
  • Another way to characterize the efficacy of a treatment that reduces in the number of microorganisms is by calculating the logarithm of the number of CFUs of the starting material divided by the number of CFUs of the material after the treatment.
  • the advantage of this method is that - since the killing of micoorganisms is generally assumed to be a first-order reaction - the log reduction of a treatment is largely independent of the actual number of microorganisms present.
  • a sterilization procedure may be required to deliver as much as log 10 reduction (which would kill off as many as 10 8 microorganisms or more), but in the case of the present invention such high efficacy is not required, or not even desirable.
  • An effective treatment procedure in the present invention would deliver at least a log 1 reduction in the number of CFUs, preferably log 2, even more preferably log 3.
  • the process it is beneficial for the process to have the thermal treatment at low or high pH, for example a low pH treatment at pH ⁇ 4, more preferably at pH ⁇ 3, even more preferably at pH ⁇ 2, the low pH treatment is in general done at pH >-1 , or for example a high pH treatment at pH > 8, more preferably pH > 9, even more preferably pH > 10.
  • the advantages of thermal treatment at high and low pH's are for example solubilization and partial hydrolysis of polymers, such as proteins, carbohydrates, such as starch as hemicellulase, and lipids, but also the reduction of viable cells will be enhanced by extreme pH's, resulting in for example a need of lower temperature and/or less time for the thermal treatment.
  • Additional advantages of high pH treatment are for example improving solid / liquid separation at the end of the thermal and enzyme treatments, improved solubilization of protein and fat, and ammonia stripping for feedstocks having high ammonia content.
  • Chemicals to be used for adjustment of the pH can be for example hydrochloric acid, phosphoric acid, and sulphuric acid for lowering the pH, or for increasing the pH potassium hydroxide and sodium hydroxide.
  • the present invention hardly any biogas is formed during the enzyme treatment of the organic material and the possible biogas production takes place in the biogas fermenter when applied.
  • Another advantage of the present process is that the enzymes used are hardly inactivated or consumed by microorganisms present in this step.
  • the low numbers of viable microorganisms present in the enzyme treatment have hardly any effect on the enzymes added and their activity.
  • the heat-treatment needs the addition of energy to the sludge or other organic material. It is noticed that the addition of this energy is compensated by an increased biogas production compared to the situation without this heat-treatment. In most cases even more energy is produced in the form of biogas than is needed for the heat- treatment.
  • the organic material can be pre-treated to make the material more accessible to the enzymes.
  • the pretreatment can for example be a mechanical, chemical or thermal pretreatment or a combination thereof.
  • a steam explosion treatment or a high temperature treatment of more than 120 °C are examples of thermal treatment.
  • Chemical oxidation or chemical hydrolysis (for example using strong an acid or alkaline compound) can be used as chemical pretreatment.
  • Ultrasonic treatment or grinding (or blending or homogenizing) are examples of mechanical pretreatments.
  • a lysing enzyme a protease, a lipase and a cellulase, and optionally amylase, are added.
  • Said enzymes make the degradation of organic material possible in the pasteurized or heat-treated medium, in which microbial growth is limited. This enzyme treatment may result in an improved biogas production lateron in the process compared to a process wherein no enzyme is added.
  • an enzyme composition comprising a lysing enzyme and a cellulase or a lysing enzyme and a protease, preferably a lysing enzyme, a protease and a cellulase, more preferably a lysing enzyme, a protease, a lipase and a cellulase.
  • amylase, phytase and/or hemicellulase is used.
  • the present invention therefore provides an enzyme composition or a kit of parts comprising a lysing enzyme and a cellulase or a lysing enzyme and a protease, preferably a lysing enzyme,, a protease and a cellulase, more preferably a lysing enzyme,, a protease, a lipase and a cellulase, and optionally amylase, phytase and/or hemicellulase.
  • This enzyme composition or a kit of parts is advantageously suitable for use in the process of the invention. Additional enzymes can be used in the present process or in the composition of the invention.
  • lysing or lytic enzyme an enzyme that is capable of lysis of the cell wall of a microorganism.
  • Microorganisms include bacteria, fungi, archaea, and protists; algae; and animals such as plankton and the planarian.
  • the microorganism is a bacterium, fungus, yeast or alga.
  • a microorganism or microbe is an organism that is unicellular or lives in a colony of cellular organisms.
  • the lysing enzyme can for example be a protease.
  • lysing enzymes are lysozyme or muramidase (from chicken egg), lysing enzyme from Trichoderma harzianum, lytic enzyme from Lysobacter such as Lysobacter enzymogenes, lyticase from Arthrobacter luteus and Mutanolysin from Streptomyces globisporus ATCC 21553, labiase from Streptomyces fulvissimus or lysostaphin from Staphylococcus.
  • lysing enzymes can for example be purchased from Sigma-Aldrich®.
  • the cell contents of the cells are liberated which make enzymes present in the sludge cells or bacterial material available for use in the process of the invention on top of the added enzymes.
  • the liberated enzymes may even contain lytic enzymes which may lyse other bacteria.
  • the added protease, lipase and/or cellulase and optionally amylase, hemicellulase and/or phytase, together with the enzymes that are released from the lysed cells, will decompose the long chains of the complex proteins, lipids and carbohydrates into shorter parts.
  • polysaccharides can be converted into oligosaccharides and/or monosaccharides.
  • Proteins can be split into peptides and amino acids.
  • other enzyme compositions can be used which promote the degradation of the organic material.
  • the enzymes can be mixed to form a selected combination or can be produced as a mixture by a selected strain during selected fermentation conditions.
  • the enzyme mixture obtained from a fermentation broth of a fungus such as Trichoderma, Aspergillus or Talaromyces or a bacterium such as Bacillus can be used in combination with a lysing enzyme.
  • the enzyme mixture can be designed in relation to the composition of the sludge or other organic material added.
  • the enzyme composition or enzymes can be added as in a one-step or a multi- step process.
  • a multi-step process allows the optimization of the process for, for example, the properties of the enzymes. So the cellulase and protease treatment can be done separately, or a cellulase and protease treatment can be repeated.
  • one of the enzymes used is thermostable.
  • the activities in the enzyme composition may be thermostable.
  • this means that the activity has a temperature optimum of 60°C or higher, for example 70°C or higher, such as 75°C or higher, for example 80°C or higher such as 85°C or higher. All activities in the enzyme composition will typically not have the same temperature optima, but preferably will, nevertheless, be thermostable.
  • Cellulases are enzymes that hydrolyze cellulose ( ⁇ -1 ,4-glucan or ⁇ D-glucosidic linkages) resulting in the formation of glucose, cellobiose, cellooligosaccharides, and the like. Also cellulase-enhancing proteins such as GH61 are comprised by the term cellulase herein.
  • EG endoglucanases
  • CBH cellobiohydrolases
  • BG ⁇ -glucosidases
  • ⁇ -glucosidase acts to liberate D-glucose units from cellobiose, cello-oligosaccharides, and other glucosides (Freer, J. Biol. Chem. vol. 268, no. 13, pp. 9337-9342, 1993).
  • Proteases protein degrading or modifying enzymes are for instance endo- acting proteases (serine proteases, metalloproteases, aspartyl proteases, th iol proteases), exo-acting peptidases that cleave off one amino acid, or dipeptide, tripeptide etceteras from the N-terminal (aminopeptidases) or C-terminal (carboxypeptidases) ends of the polypeptide chain.
  • endo- acting proteases serine proteases, metalloproteases, aspartyl proteases, th iol proteases
  • exo-acting peptidases that cleave off one amino acid, or dipeptide, tripeptide etceteras from the N-terminal (aminopeptidases) or C-terminal (carboxypeptidases) ends of the polypeptide chain.
  • Lipases or fatty material splitting enzymes are for instance triacylglycerol lipases, phospholipases (such as A- ⁇ , A 2 , B, C and D) and galactolipases.
  • Hemicellulase is a collective term for a group of enzymes that break down hemicellulose. Examples are xylanase, ⁇ -xylosidase, a-L-arabinofuranosidase, a- galactosidase, acetyl esterase, ⁇ -mannosidase and ⁇ -glucosidase.
  • a phytase (myo-inositol hexakisphosphate phosphohydrolase) is any type of phosphatase enzyme that catalyzes the hydrolysis of phytic acid (myo-inositol hexakisphosphate) which is an indigestible, organic form of phosphorus that is found in grains and oil seeds, and releases a usable form of inorganic phosphorus.
  • lysing or lytic enzyme an enzyme that is capable of lysis of the cell wall of a microorganism.
  • Microorganisms include bacteria, fungi, archaea, and protists; algae; and animals such as plankton and the planarian.
  • the microorganism is a bacterium, fungus, yeast or alga.
  • a microorganism or microbe is an organism that is unicellular or lives in a colony of cellular organisms.
  • the lysing enzyme can for example be a protease.
  • lysing enzymes are lysozyme or muramidase (from chicken egg), lysing enzyme from Trichoderma harzianum, lytic enzyme from Lysobacter such as Lysobacter enzymogenes, lyticase from Arthrobacter luteus and Mutanolysin from Streptomyces globisporus ATCC 21553, labiase from Streptomyces fulvissimus or lysostaphin from Staphylococcus.
  • lysing enzymes can for example be purchased from Sigma-Aldrich®.
  • the cell contents of the cells are liberated which make enzymes present in the sludge cells or bacterial material available for use in the process of the invention on top of the added enzymes.
  • the liberated enzymes may even contain lytic enzymes which may lyse other bacteria.
  • the sludge or other organic material is preferably pasteurized or heat-treated at a temperature of 65 to 120 °C, more preferably at 65 to 95 °C and therefore the enzyme has preferably an optimal activity at the pasteurization or heat-treatment temperature or at 0 to 10 °C lower, so in general at a temperature of 55 to 90 °C.
  • the enzyme is preferably stable at the selected pasteurization or heat-treatment temperature for a sufficient time, so for example for at least 30 minutes, preferably at least for 1 hour. By stability is meant that after a certain period of incubation time, the activity under the reaction conditions is at least half of the starting activity.
  • the pH during the enzyme treatment will be in general between 4 and 9, preferably between 4 and 8, more preferably between 5 and 8.
  • the enzyme is preferably stable at the selected pH for a sufficient time, so for example for at least 30 minutes, preferably at least for 1 hour.
  • the use of enzymes for hydrolysis of sludge or other organic material was found to produce a high extraction yield of the organic matter in the liquid phase, in general higher than 75 %. For (pig) manure or sludge this will be higher than 40 %.
  • the enzymes hydrolyze water-binding structures (proteins, polysaccharides), without producing polymer structures by themselves, like microorganism do.
  • the enzymes provide the reduction of viscosity of the phases, what facilitates solid/liquid separation.
  • Another way in which the enzymes can facilitate solid/liquid separation is by lowering the emulsification properties.
  • proteases and lipases are known to be helpful in this respect.
  • the volume of solid phase is reduced. Processing and disposal of solid residues, which are important cost factors in wastewater plants, are facilitated and cheaper.
  • these properties of the enzymatic process simplify largely the solid/liquid separation and are surprisingly very advantageous in comparison to processes based on microbial hydrolysis.
  • the ability in the present invention of extracting with high yield the organic matter in soluble form is advantageous for the processing of this organic matter to biogas.
  • soluble substrate it is possible to apply the technology of high load anaerobic reactors based on biomass retention (for example UASB and EGSB). This technology is less attractive in conventional processes using partially and slowly degradable insoluble substrates.
  • the pasteurization or heat-treatment step can be done before or (partly) during the enzyme treatment.
  • the pasteurization or heat-treatment time may be as long as the enzyme treatment time.
  • the enzyme treatment time will depend on for example the temperature used, the substrate, the enzyme(s) used, and the concentration of the enzymes. In general the enzyme treatment will take 2 to 50 hours, preferably 3 to 30 hours.
  • the enzyme treatment can be batch-wise or continuously, for example a CSTR reactor can be used.
  • the treated organic material is treated to deactivate at least part of the enzyme(s) present.
  • a heat shock a pH change can be applied.
  • the enzymes used may be selected to become de- activated during the enzyme treatment process after the enzymes have fulfilled their job. In general the enzymes used, are chosen not to have a substantial negative effect on the possible ethanol or biogas production later on in the process or even to contribute in a positive way in the ethanol or biogas production phase.
  • the solid/liquid separation step the liquid fraction is separated from the solid fraction of the treated organic material.
  • optimal conditions are chosen during the solid/liquid separation such as pH, temperature, addition of flocculants or filter aids etc.
  • Suitable separation techniques can be used such as decantation, filtration, centrifugation or combinations thereof.
  • flocculant or filter aid is added before the separation takes place in order to improve the separation.
  • flocculants and filter aids which are biologically degradable such as cellulose are advantageously applied.
  • the obtained filter cake or centrifuge sludge may be washed.
  • the wash liquor is combined with the primary obtained filtrate or supernatant.
  • the solid fraction from the solid/liquid separation can be processed or used for example by incineration (combustion), composting or spreading on cultivated areas, or forests.
  • the present process having a temperature treatment step allows composting or spreading of the solid fraction without a further thermal treatment of the solid fraction which is often required in case of spreading of sludge or other biomass.
  • anaerobic or aerobic conditions can be maintained. In general no special measures have to be taken to keep anaerobic conditions.
  • the liquid fraction of the liquid/solid separator can be introduced into the ethanol fermentation reactor or ethanol fermenter.
  • Glucoamylase, beta-glucosidase or beta- xylosidase can be used to break down the dextrins, glucans or xylans to form simple sugars.
  • Glucoamylase can be present in the enzyme treatment and/or in the ethanol fermentation reactor.
  • Yeast is present in the ethanol fermenter to convert the sugar to ethanol (and carbon dioxide).
  • a yeast may be used that is able to convert C5 and C6 sugars.
  • a yeast that is capable of converting C5 sugars is a recombinant yeast, for example transformed to comprise a gene encoding xylose isomerase.
  • This ethanol fermentation can be done batch-wise or continuously, preferably the ethanol production is done batch-wise.
  • the fermentation broth or mash is then allowed to ferment for 20 to 120 hours, preferably 40 to 70 hours, resulting in a mixture that contains about 15% ethanol and added yeast.
  • the fermented mash is pumped into a distillation system, for example a multi- column system, where additional heat is added.
  • the columns utilize the differences in the boiling points of ethanol and water to boil off and separate the ethanol.
  • a 95% ethanol by volume is a possible product from these columns.
  • the liquid residue from this process, called stillage contains amongst other components yeast solids and water.
  • the yeast solids may be removed using separation techniques like centrifugation, decantation or filtering. Another option is lysing the yeast to inactivate the yeast as well as releasing valuable compounds from the yeast.
  • the liquid stillage can be introduced in a biogas reactor.
  • the liquid fraction from the enzyme treatment step can be directly used in a biogas reactor.
  • Upflow anaerobic filters, UASB, anaerobic packed bed, AF (anaerobic filter) and EGSB reactors are examples of high-rate digesters on industrial scale. Especially UASB and EGSB reactors offer benefits of high- rate digesters when applied at high organic loading rates.
  • the use of liquid and solubilized substrate in the biogas reactor enables a very high loading of the reactor
  • the HRT in the EGSB digester is between 3 to 100 hours, more preferably between 3 and 75 hours, even more preferably between 3 and 60 hours and most preferably between 4 and 25 hours.
  • the HRT in a IC reactor is between 3 to 100 hours, more preferably between 10 and 80 hours and most preferably between 15 and 60 hours.
  • the HRT in the UASB digester is between 10 to 100 hours, more preferably between 20 and 80 hours and most preferably between 20 and 50 hours.
  • the HRT in the CSTR digester is between 1 to 20 days, more preferably between 2 to 15 days and most preferably between 2 to 10 days. In general no recycling of liquid to the first stage (enzyme treatment) will take place.
  • the HRT in the anaerobic membrane bioreactor is between 3 to 12 days, more preferably between 4 and 10 days. From the liquid effluent of the biogas reactor nitrogen (N), phosphor (P) and potassium (K) can be obtained for use as fertilizer.
  • N nitrogen
  • P phosphor
  • K potassium
  • the recycling liquid from the biogas fermenter, microorganisms will be present that will start producing biogas in the first phase in case of liquid recycling to this phase. If recycling of liquid is desired, measures have to be taken that no biogas production will occur in the first phase due to introducing anaerobic microorganisms, for example the recycling liquid can be pasteurized or sterilized.
  • the pH of the biogas reactor will in general be between pH of 3 and 8, preferably between 6 and 8. Generally no measures have to be taken to control the pH, the system is capable to maintain this pH itself. In case the substrate of the biogas reactor is outside this pH range or outside the preferred pH range, so for example at pH of 5 or lower, or at pH of 9 and higher, the pH of this substrate can be neutralized to for example between 6 and 8.
  • the process of the invention is directed to an optimal use of the energy that is applied for the thermal treatment of the organic material. Directly applying the next steps of the process of the invention may reduce energy losses in the form of heat that is lost in the enzymatic treatment, solid/liquid separation, and optionally ethanol fermenter and biogas production.
  • the enzymatic treatment, liquid/solid separation, and optionally ethanol fermenter and biogas production may take place at temperatures almost the same as the thermal treatment temperature without the addition of extra heating or other forms of energy supply. Therefore the solid/liquid separation preferably takes place at 70 to 50 °C.
  • the ethanol and biogas production preferably takes place at 65 to 30 °C and most preferably takes place at 65 to 40 °C.
  • the excess heat and cooling heat applied in the distillation process may be used to heat and cool the organic material in the enzyme treatment step.
  • the process of the invention can be performed in many ways including batch, fed batch or continuously loaded reactors or fermenters or a combination thereof.
  • batch reactors are preferred.
  • biogas production phase continuous reactors like UASB or EGSB are preferred
  • Enzymes used for the incubations of the various feedstocks were commercially available enzyme samples of the classes of hemicellulases, cellulases, proteases and lysozyme.
  • the hemicellulase product used was Bakezyme ® ARA10.000
  • the cellulase product was Filtrase ® NL
  • the lysozyme product was Delvozyme ® L
  • the protease product applied was Delvolase ® , a bacterial protease. All enzyme products are produced by DSM Food Specialties.
  • the method was a combination of precipitation of protein using trichloro acetic acid (TCA) to remove disturbing substances and allow determination of the protein concentration with the colorimetric Biuret reaction.
  • TCA trichloro acetic acid
  • a copper (II) ion is reduced to copper (I), which forms a complex with the nitrogens and carbons of the peptide bonds in an alkaline solution.
  • a violet color indicates the presence of proteins.
  • the intensity of the color, and hence the absorption at 546 nm, is directly proportional to the protein concentration, according to the Beer-Lambert law.
  • the standardisation was performed using BSA (Bovine Serum Albumine) and the protein content was expressed in g protein as BSA equivalent/L or mg protein as BSA equivalent /ml.
  • the protein content was calculated using standard calculation protocols known in the art, by plotting the OD 546 versus the concentration of samples with known concentration, followed by the calculation of the concentration of the unknown samples using the equation generated from the calibration line.
  • COD Chemical Oxygen Demand
  • TS total solids
  • TSS Total suspended solids
  • ash volatile solids (VS) ( ⁇ organic dry matter), volatile suspended solids (VSS, are an indication of the maximum cell biomass present in the system), solubilization yield, total Kjeldahl nitrogen, ammonia nitrogen
  • Biogas composition (CH4 and C02) was measured using gas chromotography, equipped with a thermal conductivity detector (TCD).
  • Volatile fatty acids (VFA) and ethanol concentration were measured using a gas chromatograph (Shimadzu GC-2010 AF, Kyoto, Japan), equipped with a flame ionization detector (FID) (Angelidaki et al., 2009).
  • the total protein content was calculated from the total Kjeldahl nitrogen content multiplied by 6.25. Except for pig manure, for which the content of ammonia nitrogen was subtracted from the total Kjeldahl nitrogen, followed by multiplication with 6.25.
  • the sample is weighed into a suitable vial and lyophilized. After lyophilization, the weight is recorded. The dried residue is homogenized and approximately 1 gram is weighed into an extraction shell (type Whatman cellulose extraction thimbles 26 mm x 60 mm single thickness). This shell is boiled in dichloromethane (Merck for liquid chromatography quality) for 1 .5 hour in a Soxtec exctraction unit (Soxtec system MT 1043 extraction unit), at 1 19 °C, using a pre-weighed appropriate Soxtec Cup. Then, the shell is refluxed for 1 hour. Subsequently the dichloromethane is evaporated.
  • dichloromethane Merck for liquid chromatography quality
  • the increase in weight of this cup is the fat content extracted from approximately 1 gram dried material. After correction for the dry weight determined during the lyophilisation step, the fat content per sample as such is expressed in g/Kg.
  • Carbohydrates and lignin content were determined according to "Determination of structural carbohydrates and lignin in biomass", A. Sluiter et al. Technical report NREL/TP-510-42618.
  • Spent Grain Brewers spent grain (BSG), as milled and dried material was obtained from a commercial brewery.
  • the material was suspended in distilled water to a dry matter content of 10%, in a double-walled closed glass reaction chamber, which is connected to a circulating water bath, in which the water temperature was set to the desired temperature, i.e. 70°C or 90°C.
  • the pH of the suspension as such was pH 6.6, and was adjusted to pH 1.5, 4, 1 1 .5, using 4N HCI or 4N NaOH. Subsequently, the slurries were incubated for certain time periods, while stirred.
  • the BSG suspension was adjusted to the desired pH as described before, and treated in a flask in a sterilizer for the desired period of time, assuming a temperature of 120°C. After the different pretreatments, the slurries were cooled down, adjusted to pH 7.5 using HCI or NaOH, and incubated for 4 h at 60°C, with the addition of 100 mg Delvolase ® per g BSG dry matter.
  • the incubate was cooled down, pH adjusted to pH 5.0, and further incubated at 50°C for 24 h, with the addition of 7.5 mg protein derived from Bakezyme ® ARA10.000 per g BSG dry matter and 9 mg protein derived from Filtrase ® NL per g BSG dry matter.
  • the slurry was then cooled to 50-52°C, and 600 g of protein derived from Bakezyme ® ARA10.000 and 720 g protein derived from Filtrase ® NL, each of them in a total volume of 8 kg solution, were added for further incubation of the mixture for 20 h at 42-45°C, at the indicated stirrer speed. Finally, the pH of the slurry was adjusted to pH 7.4 by the addition of 10.2 kg 25% NaOH.
  • the second part of the slurry was filtered similarly as described for the first one, except for the washing, which was omitted in the second cycle.
  • This second cycle resulted in a primary filtrate of 345 kg.
  • the combined primary filtrates amounted to 510 kg, which was mixed with 100 kg of the washing liquor, resulting in a total amount of 610 kg of final filtrate for fermentation experiments.
  • the aerobic total plate counts of the starting slurry, and the slurry after the final enzyme incubation with Bakezyme ® ARA10.000 and Filtrase ® NL were determined and showed to have decreased from > 1 -10 8 CFU/ml in the starting slurry, to 100 CFU/ml after the final enzyme treatment.
  • composition of the slurry before filtration, and of the primary filtrate and the final filtrate (combination of primary filtrate with a portion of the washing liquor) is given in Table 3.
  • the pig manure concentrate was obtained according to a process as described in "Conversion to manure concentrates, Kumac Mineralen - Description of a case for handling livestock manure with innovative technology in the Netherlands", Baltic Compass Report, 201 1 ). Approximately 1 L of this mixture was heated to 90°C, while mixed, in a set-up as described in Example 1 .
  • Portions of approximately 100 ml of the cooled pretreated slurry were transferred to similar small-scale double walled reaction chambers, and different enzymes and treatments were tested with regard to the reduction of the number of microorganisms. The different tests performed are described in Fig. 1 .
  • the dosages of enzymes applied were similar as described in Example 1 , and the dose of Delvozyme ® L was 50 mg enzyme product per g pig manure dry matter.
  • Pig manure concentrate of approximately 30% dry matter was diluted in 0.1 M NaOH to a dry matter content of 10%.
  • a similar set-up as described in Example 1 was used to compare 2 different pretreatment methods. Both methods started with a 4h incubation at 90°C. Subsequently, the slurry was cooled, pH adjusted to pH 7, and incubated for 4 h at 30°C, this was shown in Example 4 to be very beneficial for reduction of the number of microorganisms in the slurry.
  • method A the slurry was then incubated for 3 h at 90°C, cooled down, adjusted to pH 8, and incubated for 20 h with the addition of Delvolase ® and Delvozyme ® L at 40°C, next pH was adjusted to pH 4.5, Bakezyme ® ARA10.000 and Filtrase ® N L were added, and the slurry was incubated for another 20 h at 40°C.
  • method B the 3 h 90°C incubation at pH 7 was performed after the Delvolase ® and Delvozyme ® L incubation. The remaining 20 h incubation with Bakezyme ® ARA10.000 and Filtrase ® NL was then performed after cooling down from 90°C and pH adjustment to pH 4.5.
  • the amounts of enzymes added per g dry matter of the pig manure was similar as stated in Example 1 , for Delvolase ® , Bakezyme ® ARA10.000 and Filtrase ® NL.
  • the dose of Delvozyme ® L was 50 mg enzyme product per g pig manure dry matter.
  • pH adjustments 4N NaOH or 4N HCI were used.
  • Table 5 Total aerobic plate counts of the pig manure after finalization of each of the different steps in the pretreatment process.
  • Method B appears to have a greater impact on the reduction of microorganisms, as the plate count is below 100.
  • the plate count reduction in Method A is also substantial, but appears to be a bit more fluctuating. For that reason, Method B with an intermediate step for germination of surviving spores, followed by lytic enzyme incubation and cellulase and hemicellulase incubation is preferred.
  • the solubilization yield was 40% for both of these methods.
  • Pig manure concentrate was obtained from a manure trader.
  • the composition of this material is presented in Table 6.
  • Solubilized pig manure was prepared in a similar process set-up as described in Example 2.
  • 205 kg of pig manure concentrate was transferred to the stainless steel tank reactor to which 400 L water was added.
  • the slurry was mixed at 50-55 rpm and heated to 90-95°C, using 0.5 bar steam in the heating jacket.
  • 13.5 kg of 25% NaOH was added, followed by incubation at 90-92°C for 4 h, at a stirrer speed of 40 rpm.
  • the pH had dropped to 8.5, and the slurry was cooled to 30- 32°C, using cold water in the cooling jacket of the reactor.
  • the pH was adjusted to pH 7 by addition of 27.3 kg 10% HCI for germination of potentially remaining bacterial spores, during incubation of 4 h at a stirring speed of 50 rpm. Subsequently, the temperature was increased to 60-62°C, the pH was adjusted to pH 8, using 2.7 kg 25% NaOH, and 8 kg of Delvolase ® and 4 kg of Delvozyme ® L was added. After 4h incubation at 60-62°C and a stirring speed of 25-30 rpm, the slurry was heated to 90°C and incubated at that temperature for 3h. The the slurry was cooled to 50-52°C, the pH was adjusted to pH 4.5 by addition of 67.7 kg 10% HCI.
  • Substrate number 1 (Brewer spent grains-BSG) was tested more extensively: both the soluble fraction (centrifugate or filtrate), the total solution
  • the reactors had the same starting inoculum: 20% volume of anaerobic granular sludge from a full-scale reactor, purchased from potato waste water processing plant Germany (UASB), were operated at the same temperature 36 ⁇ 2 °C, the pH was controlled at 7.2 ⁇ 0.3 with NaOH/H2S04 (2M).
  • the superficial flow velocity in the EGSB was 8m/h.
  • the organic loading rate (OLR-g-COD/L.d) was then stepwise increased up to its maximum: good COD conversion (>60%) and no VFA accumulation.
  • the two substrates were tested: brewer spent grains (BSG) and pig manure (PM), which underwent the pre-treatment as described above.
  • the composition of the substrate into each reactor is presented in Tables 3 and 6.
  • the substrate was diluted in order to apply the desired organic loading rate (g-COD/L.d) and hydraulic retention time (HRT).
  • centrifugate or filtrate soluble fraction of the pre-treated material
  • suspension whole pre-treated material
  • original material non-pretreated
  • CSTR, 5L a continuous system
  • the centrifugate was also tested in the SBR (CSTR including settling cycles, in order to allow a longer retention time of the suspended solids, including the biomass).
  • EGSB 38L only the liquid fraction was tested.
  • the centrifugate fraction was tested both in an SBR and in the EGSB.
  • the combination of the pre-treatment, solid liquid separation and reactor configuration showed advantageously the highest methane production rates (>3 fold) and 20% increase of the methane yield.
  • VFA acetic+propionic acid

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Abstract

La présente invention concerne un procédé de traitement d'une boue ou d'une autre matière organique, le procédé comprenant : le traitement de la boue ou de la matière organique pour réduire le nombre de micro-organismes viables se trouvant dans la matière organique ; le traitement de la matière organique avec une enzyme de lyse et une cellulase ou avec une enzyme de lyse et une protéase, de préférence avec une enzyme de lyse, une protéase et une cellulase, et de manière davantage préférée avec une enzyme de lyse, une protéase, une lipase et une cellulase, éventuellement avec une amylase, une phytase et/ou une hemicellulase ; et la séparation entre la fraction liquide et la fraction solide de la matière organique traitée par les enzymes. L'invention concerne en outre une composition d'enzyme ou un kit de parties comprenant une enzyme de lyse, une protéase, une lipase et une cellulase, et éventuellement une amylase.
PCT/EP2012/062385 2011-06-29 2012-06-26 Procédé de traitement d'une boue ou d'une autre matière organique WO2013000927A1 (fr)

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PCT/EP2013/063306 WO2014001349A1 (fr) 2012-06-26 2013-06-25 Phytase utilisée en production de biogaz
EP13730910.0A EP2864490A1 (fr) 2012-06-26 2013-06-25 Phytase utilisée en production de biogaz
US14/410,311 US20150337337A1 (en) 2012-06-26 2013-06-25 Phytase in biogas production
CN201380033601.6A CN104411829A (zh) 2012-06-26 2013-06-25 生物气体生产中的植酸酶

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DE102015013859A1 (de) 2015-10-28 2017-05-04 Biopract Gmbh Verfahren zur proteolytischen Behandlung von Gärresten einer Biogasanlage
CN106660845A (zh) * 2014-09-09 2017-05-10 诺维信公司 用于用酶处理增强污泥的脱水性能的方法
CN113880394A (zh) * 2021-08-31 2022-01-04 海环绿源环保科技(上海)有限公司 一种植物酶污泥脱水剂和污泥脱水的方法
CN116355882A (zh) * 2023-04-10 2023-06-30 北京电子科技职业学院 一种丝状菌膨胀污泥控制生物酶制剂及其制备方法和应用

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CN106660845A (zh) * 2014-09-09 2017-05-10 诺维信公司 用于用酶处理增强污泥的脱水性能的方法
DE102015013859A1 (de) 2015-10-28 2017-05-04 Biopract Gmbh Verfahren zur proteolytischen Behandlung von Gärresten einer Biogasanlage
CN113880394A (zh) * 2021-08-31 2022-01-04 海环绿源环保科技(上海)有限公司 一种植物酶污泥脱水剂和污泥脱水的方法
CN113880394B (zh) * 2021-08-31 2023-10-13 芜湖海创环保科技有限责任公司 一种植物酶污泥脱水剂和污泥脱水的方法
CN116355882A (zh) * 2023-04-10 2023-06-30 北京电子科技职业学院 一种丝状菌膨胀污泥控制生物酶制剂及其制备方法和应用
CN116355882B (zh) * 2023-04-10 2023-11-10 北京电子科技职业学院 一种丝状菌膨胀污泥控制生物酶制剂及其制备方法和应用

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