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    • 专利摘要:
    Biological pretreatment method for hydrolysis processes. A method of biological pretreatment of organic matter prior to a hydrolysis process is described, which comprises: - submit an aqueous stream containing organic matter in a concentration between 0.1-100 g/l to culture of hydrolytic enzyme-producing organisms present in said stream under specific conditions without external input of nutrients and in agitation, organic matter being the own substrate from which they are grown in the stream, Before subjecting the enriched stream to a biological process of hydrolysis at a stage subsequent to pretreatment. The hydrolysis process is preferably an anaerobic method, the pretreatment being specially designed to be coupled in the treatment of sludge, such as a sewage treatment plant, to improve the performance of the anaerobic digestion process thereof. The installation is covered for pretreatment and its coupling to an industrial plant that produces waste and are treated by hydrolysis. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2555358A1
    申请号:ES201530271
    申请日:2015-03-03
    公开日:2015-12-30
    发明作者:Marina ARNALDOS ORTS；Carlos RODRÍGUEZ LÓPEZ；María Del Mar MICÓ RECHE；Jorge J. MALFEITO SÁNCHEZ
    申请人:Acciona Agua SA；
    IPC主号:
    专利说明:

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    DESCRIPTION
    METHOD OF BIOLOGICAL PRE-TREATMENT FOR HYDROLYSIS PROCESSES
    FIELD OF THE INVENTION
    The present invention encompasses in the field of industrial processes based on the treatment by hydrolysis of organic matter, such as that contained in urban and industrial waste (sewage, landfills), sludge type of a sewage treatment plant, or agricultural, and more specifically It still focuses on the biological pretreatment of biodegradable organic matter that is treated by hydrolysis, such as sludge or sludge from depuration. Also included are the anaerobic processes of which hydrolysis is a part, which can also be very diverse: anaerobic digestion, anaerobic membrane systems, anaerobic electrochemical cells, anaerobic upflow reactors (abbreviated UASB) from Upflow Anaerobic Sludge Blanket) or similar.
    STATE OF THE TECHNIQUE
    Hydrolysis is the limiting step in anaerobic biodegradation processes. Being the phase of lower reaction speed, it limits the yield in terms of biogas production and sludge volume reduction. Therefore, in recent decades there has been a growing interest in developing methods for acceleration, mainly focused on the prior treatment of biological matter to hydrolyze, as a preparation. Four main categories of pretreatment technologies have been developed to accelerate hydrolysis: thermal, mechanical, chemical and biological pretreatments. All these technologies have the advantage of reducing anaerobic digestion time and the final sludge volume, as well! how to increase the production of biogas. However, current pretreatment technologies are characterized by high energy consumption, which calls into question the advantages obtained from their application (saving in the cost of transport and elimination of sludge; Roxburgh et al., 2006).
    The options for improving anaerobic digestion are diverse and require a pre-implantation study, since there are several factors to consider, such as the characteristics of the product to be treated (sludge), the installation and the operating conditions (Rossle and Pretorius, 1996).
    Thermal pretreatments (mainly application of a thermal phase in the
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    anaerobic digestion) normally require a significant amount of thermal energy in order to obtain a significant process improvement (Carrere et al., 2010); Improved biogas production provides the thermal energy necessary to compensate for the thermal requirements of the pretreatment system itself (Bougrier et al., 2006). Therefore, the main advantage of these systems is limited to a certain reduction in sludge biomass, but not to a reduction in energy consumption because in reality the contribution of external energy required by the anaerobic digestion systems itself is nullified by the energy produced in the process.
    On the other hand, mechanical pretreatments (mainly ultrasonic pretreatments and shear stresses) require an increase in the addition of electric energy, with a consumption of approximately 0.3 KWh per kg of volatile solid (VS) removed. Taking into account that the electrical efficiency of biogas is 30%, the increase in biogas production thanks to pretreatment does not compensate for the increase in the demand for electric energy in most cases, which makes the energy balance negative (Boehler et al., 2006).
    The chemical pretreatments are those where chemical agents are added. Although high yields are obtained through their use, they can present some drawbacks such as the introduction of chemical compounds in the waste stream and the increase in costs in the acquisition and manipulation of reagents. These processes mainly include thermo-chemical hydrolysis (Tanaka et al., 1997; Rocher et al., 1999), and advanced oxidation processes with ozone or hydrogen peroxide (Sakai et al., 1997; Huysmans et al. , 2001).
    Biological pretreatments, which constitute the state of the art in which the present invention is framed, consist of the addition of certain strains of bacteria or hydrolytic enzymes to the mud (Knapp and Howell, 1978). In this way, the disintegration and solubilization (hydrolysis) of the particulate matter is accelerated. Although they do not incur high energy consumption, the production of enzymes or certain strains of bacteria is expensive and operationally very complex, which can make the process considerably more expensive. There are a considerable number of patent documents focused on the enzymatic hydrolysis of residues with cellulose and lignocellulose, due to the difficulty in processing these components anaerobically. These documents are particularly aimed at the development of
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    Biological pretreatments for the subsequent production of biofuels by fermentation of substrates from pretreatment. In general, these pretreatments are based on the addition of external enzymes (foreign) to the material to be biodegraded (EP2559768 A1, EP2076594 B1) or on a combination of addition of enzymes and bacteria produced in the process itself (WO2010055495). In short, these pretreatments have additional costs because they are based on the external addition of enzymes, and it has been found that they do not use the bacteria themselves produced in the pretreatment to improve the subsequent process to which the material is subjected to biodegradation. That is, there is no synergy of pretreatment with a subsequent process, which is the basis of the present invention.
    On the other hand, there is also a considerable number of patent documents in the area of biological treatments of solid waste for landfills. In these treatments, different fractions (liquid and solid) are usually separated from the waste; The liquid part is generally subjected to hydrolysis and anaerobic processes while the solid passes to composting (aerobic treatment). An example of this type of documents is US 7,985,577 B2 and US 7,015,028 B2. In these treatments a synergy between the pretreatment and the subsequent process has not been observed either; The hydrolyzed liquid part is not actually used to improve the overall performance of the process (or, in this case, anaerobic treatment of solids).
    Few examples have been found in which a biological pretreatment based on the enrichment of a culture of hydrolytic bacteria is used to improve the performance of anaerobic processes. In previous studies, a laboratory-scale anaerobic reactor was enriched with hydrolytic bacteria grown externally in a nutrient-rich broth (Yu et al. 2013). The experiment carried out showed that the addition to the anaerobic digester of a culture of enriched bacteria abroad improved the solubility of organic matter by 78% and the production of volatile fatty acids by 130% during the anaerobic process, producing a 23% increase in biogas. It was shown that the enzymes that play a more significant role in the bio-augmentation (increase in the biological activity of decomposition of organic matter) of the digester were hydrolases, amylases and proteases. Despite the achievements of this approach, nutrient-rich broths such as that used by Yu et al. (2013) are expensive and therefore not applicable on an industrial scale, since it would make the process economically unfeasible.
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    An international patent application, WO 2009135967, has also been found in which a biological pretreatment is carried out using bacteria from an aerobic composting process (solid treatment process). The culture is extracted and added in an anaerobic digestion process to accelerate hydrolysis, improving yield. The limitation of this pretreatment is that it uses solids from an aerobic treatment system, then being two non-integrated processes. This implies, on the one hand, the need to add additional facilities for the aerobic treatment of solids (with the consequent cost of capital). On the other hand, aerobic treatments involve a high cost of operation and therefore, the end result is an energy cost greater than that achieved with other pretreatments (such as the present invention).
    Taking into account the aforementioned limitations detected in the technical field, a biological pretreatment based on synergy and biological self-production is proposed in this invention to prepare the organic matter capable of being hydrolyzed. The culture of organisms that produce hydrolytic enzymes and that are generated in the pretreatment grow in the own concentrated aqueous stream of organic matter to be hydrolyzed, because they are present in said stream within a heterogeneous group of organisms that accompany the organic matter and that they are capable of growing in it as a substrate, so that an external contribution of them is not necessary, and they are the most suitable to improve the performance of the subsequent process. In addition, there are no relevant additional energy costs nor are the costs in crops or nutrients increased, because concentrated aqueous streams of organic matter extracted from the industrial process in which the pretreatment phase is integrated are used, and therefore exceeds the limitation of experiments like that of Yu et al. (2013), since it is not necessary to provide nutrient-rich broths to the process. The present method of biological pretreatment is characterized by requiring only slight variations in the anaerobic processing facility where it is integrated, and for achieving the comprehensive anaerobic treatment of waste, increasing its performance by reducing new waste and increasing energy recovery; therefore, both capital and operating costs are the minimum possible.
    BIBLIOGRAPHIC REFERENCES
    Boehler, M., & Siegrist, H. (2006). Potential of activated sludge disintegration. Toilet
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    Science and Technology, 53. 207-216.
    Bougrier, C., Albasi, C., Delgenes, J.P., & Carrere H. (2006). Effect of ultrasonic, thermal and ozone pre-treatments on waste activated sludge solubilisation and anaerobic biodegradability. Chemical Engineering and Processing, 45 (8). 711-718
    Carrere, H., Dumas, C., Battimelli, A., Batstone, D.J., Delgenes, J.P. et al. (2010). Pretreatment methods to improve sludge anaerobic degradability: A review. Progress in Energy and Combustion Science: Elsevier. 1-15.
    Choate, C. E. (2011, July 26). US Patent 9,985,577: Systems and processes for treatment of organic waste materials with a biomixer.
    Choate, C. E., Sherman, P. A., & Zhang, R. (2006, March 21). US Patent 7,015,028: Process for treatment of organic waste materials.
    Hill, C., Scott, B. R., & Tomashek, J. (2008, March 6). EP 2076594 B1: Process for enzymatic hydrolysis of pretreated lignocellulosic feedstocks.
    Huysmans, G.T.A., Sharapov S.E., Mikhailovskii, A.B., & Kerner, W. (2001). Modeling of diamagnetic stabilization of ideal magneto hydrodynamic instabilities associated with the transport barrier. American Institute of Physics.
    Knapp, J.S. & Howell, J.A. (1978) Treatment of primary sewage sludge with enzymes. Biotechnol Bioeng, 20. 1221-1234.
    Morag, E. (2010, November 25). International patent application WO 2010/055495 A3: Methods and compositions for enhanced bacterial hydrolysis of cellulosic feedstocks.
    Romero, R. (2013, February 20). Patent application EP 2559768 A1: Enzymatic hydrolysis pretreatment of lignocellulosic materials.
    Rossle, W.H. & Pretorius, W.A. (2001). A review of characterization requirements for inline prefermenters. Paper 2: Process characterization. Water SA, 27 (3). 413-422.
    Roxburgh, R., Sieger, R., Johnson, B. R., Rabinowitz, B., Goodwin, S., Crawford, G. V., Daigger, G.T. (2006) Sludge Minimization Technologies- Doing More To Get Less. Proceedings of the 79th WEF Conference and Exhibition. Dallas, Texas, USA.
    Sakai, J., Nohturfft, A., Cheng, D., Ho, Y.K., Brown, M.S., and Goldstein, J.L. (1997). Identification of complexes between the COOH-terminal domains of sterol regulatory element binding proteins (SREBPs) and SREBP cleavage-activating protein (SCAP). J. Biol. Chem. 272. 20213-20221.
    Sales, M. D., Romero, G. L. I., Alvarez, G. C. J., & Fernandez, G. L. A. (2009, November 12). International patent application WO 2009/135967 A1: Pretreatment
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    Organic solid waste biological.
    Tanaka, T., Manome, Y., Wen, P., Kufe, D. W. & Fine, H. A. (1997) Viral vector-mediated transduction of a modified platelet factor 4 cDNA inhibits angiogenesis and tumor growth. Nat. Med, 3. 437-442
    Yu, S., Zhang, G., Li, J, Zhao, Z. & Kang, X. (2013). Effect of endogenous hydrolytic enzymes pretreatment on the anaerobic digestion of sludge. Bioresource Technology: Elsevier. 758-761.
    GENERAL DESCRIPTION OF THE INVENTION
    The first object of the present invention is constituted by a method of biological pretreatment of biodegradable organic matter capable of being subjected to a hydrolysis process, comprising:
    - subjecting an aqueous stream containing the organic matter in a concentration between 0.1 and 100 g / L (of the total volume of stream) to culture of organisms generating hydrolytic enzymes present in said stream, under agitation and without external nutrient supply , the organic matter being the substrate itself from which organisms are grown for enrichment in the aqueous stream, and
    - subject the enriched aqueous stream to a biological hydrolysis process at a post-pretreatment stage.
    The invention offers as! a new pretreatment of continuous or discontinuous applicability in hydrolysis processes or in any broader process of which the hydrolysis reaction is part, such as anaerobic digestion (and more specifically anaerobic digestion of sludge or primary sludge in a treatment plant ), of low cost and based on the cultivation and enrichment of the hydrolytic organisms themselves present in the stream using the organic matter itself as a substrate, for the subsequent bioamplation of the hydrolysis process to which said organic matter is subjected thanks to the hydrolytic enzymes produced by these enriched organisms. The pretreatment of organic matter is designed to optimize the growth conditions of the organisms that generate hydrolytic enzymes (also called here hydrolytic organisms), which are the ones that will subsequently accelerate the hydrolysis reaction itself to which the pretreated biomass is subjected (enriched) Additionally, it should be borne in mind that the substrate for the growth of hydrolytic organisms is the organic matter itself contained in the
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    aqueous stream that will be subsequently subjected to hydrolysis, and therefore does not depend on extra nutrient inputs. Organic matter is part of an aqueous stream (which is ultimately a waste) that always contains moisture, whose aqueous phase allows the growth of organisms, from an industrial process that is associated with the hydrolysis phase itself, either because is related to it or because it is physically close to it, so that this method of pretreatment is not external but can be integrated into the process in which the biomass is to be treated (by hydrolysis) to reduce waste or produce biogas and / or the process that originates the aqueous stream of organic matter. Thus, compared to other known biological pretreatments, it is possible to integrate that of the present invention into the production and treatment line of organic matter itself.
    In general, it should be understood within the framework of the present invention that the aqueous stream containing the organic matter is originated in a biological process of degradation, spontaneous or provoked, usable as a source of energy. Thus, organic matter is present in concentrated form in the aqueous stream (concentration between 0.1 and 100 g / L), said stream containing in turn biomass in the form of heterogeneous culture of organisms (bacteria, etc.) and nutrients . It follows from this definition that the organic matter stream subjected to pretreatment in the method described here is preferably the residue of an industrial process, either a final process residue or an intermediate residue that can still be potentially treated (as is the case of sludge or sludge from the primary decantation in a treatment plant).
    The positive impacts in the technical pretreatment field described are the following:
    - reduction of the volume of waste (such as sludge) generated in the biological hydrolysis process (for example, anaerobic) in which the pretreatment in question is applied and, therefore, of the transportation and disposal costs thereof;
    - Increase in the volume of biogas generated in the bio-increased hydrolysis process with pretreatment and, therefore, in the amount of recoverable energy in the system;
    - improvement of the energy balance and sustainability of the bio-augmented process by the
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    pretreatment, which is due to its low energy consumption and its potential effects in improving the energy production of bio-augmented processes;
    - Improvement of the speed of the bio-augmented process by the pretreatment, which favors the construction of smaller reactors for the bio-augmented processes and, therefore, a reduction in their capital costs.
    In short, the improvement in the performance of the hydrolysis process thanks to pre-treatment can result in a decrease in the production of waste, an increase in the elimination kinetics of organic matter, an increase in the solubilization of particulate organic matter or a increase in the production of biogas and, therefore, in the performance of the hydrolysis process.
    From the above, and since pretreatment and process of hydrolysis of organic matter are closely linked in the patent method, it should be understood that the present invention also encompasses an industrial process in which the aqueous stream is generated and treated. It contains the organic matter in a concentration between 0.1 and 100 g / L, which includes the biological pretreatment of the organic matter to be hydrolyzed by the above-described method of cultivation of hydrolytic organisms in agitation and without external supply of nutrients and being the external contribution of nutrients and organic matter itself the substrate from which said organisms are grown for enrichment in the aqueous stream before directing and subjecting the enriched stream to the hydrolysis stage, and where said hydrolysis stage is the organic matter treatment phase itself In the industrial process. According to this description, it should be understood that the industrial process subject to protection is characterized in that it comprises the method of biological pretreatment of the aqueous stream integrated between the phase in which said current is generated and the phase in which it is treated. .
    Another object of the present invention is an installation for the biological pretreatment of organic matter capable of being subjected to hydrolysis as defined above, attachable to an industrial installation in which said stream of organic matter is generated and treated, and comprising:
    - a biological pretreatment reactor (1), whose configuration varies according to
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    the temperature at which the hydrolytic organisms are cultured in the aqueous stream within it and whose size is defined as a function of the flow rate of the current and the hydraulic retention time thereof, which includes:
    or heating means (2) to select the hydrolytic organisms to grow and favor their cultivation;
    or stirring means (3), to ensure that the content of the reactor (1) is properly mixed during the cultivation stage;
    - pumping means (4), such as a metering pump, located at the outlet (5) of the pretreatment reactor (1), which directs the enriched current in the pretreatment stage to a device (6) in which It carries out the subsequent hydrolysis process of the second stage, which sets the hydraulic retention time of the biomass in the reactor (1).
    This installation is compact and simple, in such a way that it does not require complex devices to grow hydrolytic organisms in the biomass to be hydrolyzed, nor does it offer great complications to integrate into the generation line and treatment of aqueous currents with organic matter in an industrial plant .
    DETAILED DESCRIPTION OF THE INVENTION
    There are two preferred variants of the essential biological pretreatment method defined above: in a particular embodiment, the total aqueous stream of organic matter that will be subsequently treated by hydrolysis can be pretreated.
    In a second particular embodiment, from the total current to be hydrolyzed, only part or all of it can be previously extracted to be pretreated following the described method and, once enriched in organisms that generate hydrolytic enzymes, said fraction is added back to the rest of the stream to be hydrolyzed. In this case, the allcuot or fraction enriched in hydrolytic organisms and the enzymes they produce serve as a "catalyst" or "accelerator" in the subsequent hydrolysis process, extending to the total organic matter contained in the aqueous stream. In a preferred case, the allcuot or fraction of the stream that is deflected and subjected to cultivation of hydrolytic organisms represents between 10% and 20% of the total volume to be hydrolyzed (from the aqueous stream of organic matter), of such
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    so that this amount is sufficient to increase the hydrolysis rate and improve the process performance for the entire current. In a particular embodiment, the total volume of stream to be hydrolyzed in the second stage corresponds to the total volume of the aqueous stream from which the allcuot is extracted; therefore, said fraction represents 10% -20% of the total volume of the initial aqueous stream that contains the organic matter. But it is also possible to mix said aqueous stream with another or similar ones in the hydrolysis stage, for example in industrial processes in which more than one stream of aqueous waste is produced (primary and secondary sludge from a treatment plant); In these cases, the volume of total stream to be hydrolysed is represented by the sum of the volumes of the different streams that are mixed, and is the starting value that is taken as a reference to calculate 10% -20% in volume of the allcuota.
    Although the aqueous stream contains organic matter in a concentration between 0.1 and 100 g / L of the total volume, said concentration is preferably between 10 and 100 g / L.
    Preferably, the organic matter stream to be pretreated biologically is a wet (aqueous) residue that is generated in the industrial process itself in which the stream is treated by hydrolysis, that is, it is both a process of producing the residue and treatment before disposal / reuse by hydrolysis. In general, the pretreatment described is applicable to any industry that generates an organic waste that is treated in the industry itself: paper industry (generation of cellulose waste with subsequent treatment), food industry (canning, slaughterhouses, distillers, etc.) with treatment of sludge and other production waste. It is also possible to couple the pretreatment to the biofuel producing industry in which the waste of the materials used to generate the biofuel is treated in situ. Another applicable case is that of landfills in which treatment of all or part of the solid waste is carried out, or even in the in situ treatment of contaminated soils through bioremediation. In all these cases, the pretreatment constitutes an intermediate step between an earlier stage in which the aqueous residue containing the organic matter to be hydrolyzed is produced and the hydrolysis stage in which said residue is treated. This is the most preferred case, since no additional facilities or intermediate phases or processes are needed: the pretreatment method is simply integrated into the overall process of which the
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    hydrolysis of organic matter is part, so that all or part of the aqueous stream generated as waste in the industrial process is diverted to the stage of biological pretreatment for the cultivation of hydrolytic organisms, prior to the process of treatment by hydrolysis of Organic matter For example, if biological pretreatment is applied to a wastewater treatment process that takes place in a sewage treatment plant, sludge or sludge generated in the primary decantation stage is used as a stream of concentrated organic matter that is pretreated and, subsequently, These sludges are subjected to hydrolysis in the secondary treatment of anaerobic digestion together with the rest of the primary sludge (if applicable) and the secondary sludge, as is usual in water purification. In these cases, the water purification process comprises a) a stage of primary decantation, b) the stage of biological pretreatment of all or part of the sludge produced in said primary decantation and c) a stage of anaerobic sludge digestion, both the primary ones with the secondary sludge generated in a secondary stage, which is where the sludge stream enriched with pretreatment is added / applied. In this embodiment, it is important to emphasize that the enrichment of hydrolytic organisms by pretreatment of a fraction of the primary sludge allows the process to be carried out continuously or discontinuously and results in a global improvement of the sludge hydrolysis process in which it is integrated; that is, there is a synergy between the pretreatment and the subsequent hydrolysis process (which is part of the global water purification process), thus increasing the overall performance.
    Thus, if the pretreatment is integrated in the sludge line of a wastewater treatment process in a sewage plant, then the process in question preferably comprises at least the following essential stages:
    - divert all the current or a fraction of primary sludge generated in a first phase of decantation of the inlet water to the purification plant and direct said stream or fraction to cultivate and enrich the hydrolytic organisms;
    - subject the current or fraction of primary sludge diverted to cultivation of the hydrolytic organisms present in said sludge, in agitation and without external supply of nutrients, and
    - pumping the stream or fraction of primary sludge enriched in hydrolytic organisms to an anaerobic digestion process of a mixture formed by the primary sludge and secondary sludge generated in a second phase of water treatment.
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    From this description, as well as that indicated above, it follows that there are two particular embodiments. In a first realization of the method, the entire volume of the primary sludge generated in the first phase of wastewater decantation is diverted from the general sewage sludge stream to be enriched in hydrolytic organisms by means of the pretreatment described. In this way, the total enriched sludge stream is returned after the pretreatment to the general cycle of the treatment plant, where together with the secondary sludge it undergoes anaerobic digestion. On the other hand, in a second realization, only a part or fraction thereof is diverted from the primary sludge stream to be directed to the pretreatment, according to the indicated conditions (volume of the fraction between 10% and 20% of the total volume of the sludge stream to be hydrolyzed). In this way, said fraction of enriched sludge is directed after pre-treatment to anaerobic digestion along with a mixture formed by the rest of non-pretreated primary sludge and secondary sludge. In this case, the allcuota has a volume between 10% -20% of the total volume represented by the sum of the primary sludge stream and the secondary sludge stream.
    It has to be taken into account that it is normally believed in the technical field that within the hydrolytic organisms in these processes bacteria are the main participants in the hydrolysis, but this statement is too limiting because there are other organisms, more developed, that also generate enzymes hydrolytic and that are present in the industrial aqueous streams that contain organic matter. Thus, the cultivation of hydrolytic bacteria in the pretreatment object of interest is a preferred case, but not a limitation of the group of organisms to be cultivated. It seems clear that the type of hydrolytic organisms to be cultivated (generators of hydrolytic enzymes) in pretreatment will depend on the nature and properties of the selected residual current and the organic matter that it contains. In addition, it is possible to vary and modulate the culture conditions to favor the growth and proliferation of some organisms or others, as well as to vary and modulate said pretreatment conditions to enhance the production of the desired hydrolytic enzymes by said organisms (both are enriched in the current under the same conditions, having a causal relationship of immediate effect). For this reason, limiting the invention to specific cultivation conditions would unnecessarily limit its scope of protection. However, in the case of hydrolytic organisms, which may preferably be bacteria, the temperature at which the current is grown
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    it is preferably between 25 ° C and 65 ° C and more preferably between 30-60 ° C. In a particular embodiment, the current is subjected to the culture in mesophilic regime, that is between 25 ° C-45 ° C. In another particular embodiment, it is subjected to thermophonic regimen, that is between 45 ° C-65 ° C.
    Also preferably, in the pretreatment, the aqueous stream is subjected to selection of hydrolytic organisms during a hydraulic retention time (of solids) between 24-48 hours. The culture of the organisms in the pretreatment is preferably carried out at a pH between 4 and 6, being more preferably of 5. This low pH is due to the breakdown of complex molecules to form volatile fatty acids; As long as the pH is maintained above this value, the process is working properly.
    In short, hydrolytic organisms that are enriched in pretreatment due to the temperature and retention time thereof belong to a broad consortium of microorganisms. In general, the aqueous stream to be treated, whatever its origin (for example the active primary sludge of a treatment plant) contains a very varied culture of microorganisms, and signaling to a specific group is complex and, in general, of little use. What determines the operation of the method is not the phylogenetic classification of organisms but the hydrolytic enzymes that they secrete in pretreatment. However, by providing more precise information on the method in question to be protected, it can be said that organisms are preferably bacteria, and cultured bacteria are preferably those that secrete in pretreatment (and that cause an improvement in the subsequent hydrolysis process ) enzymes of the hydrolase family. Specifically, the main ones are preferably selected from the group consisting of: lipases, proteases, cellulases and amylases.
    In line with what has been described with respect to the method, the pumping means contained in the pretreatment installation propel the enriched stream to be treated at the pretreatment reactor outlet which will be treated in the subsequent hydrolysis stage. This stream will be, in one embodiment, the entire aqueous stream to be hydrolyzed, or in another alternative embodiment it will be the part or all deviated from the general aqueous stream, which is preferably of a volume comprised between 10% and 20% of the total volume of the stream to hydrolyze. In addition, as stated above, the size of the
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    The reactor depends not only on the flow rate of the aqueous stream to be pretreated but also on the retention time of said stream inside the reactor. In this sense, since the retention time in the method is preferably set between 24 and 48 hours, then the reactor size is favorably reduced.
    In a preferred case of the method described above, a concentrated aqueous stream of organic matter is pretreated from an associated process, related, or close to the hydrolysis process to which said stream (in general, a residue) is to be subjected, of such This is also the process in which pretreatment is implemented. In this case, the simple and compact installation of biological pretreatment object of patent is also coupled to a higher installation in which waste of organic matter is produced and these are treated by hydrolysis, for example by anaerobic digestion (in a treatment plant) , so that the pretreatment reactor of the installation is connected at its entrance to a conduction element of the residual organic matter stream that is produced in another device of the upper installation (for example, a primary decanter), and its exit to the device where said stream of residual organic matter is usually treated by hydrolysis (in the particular case mentioned, a mixed sludge digestion tank - primary and secondary). In this case, it is for example an aqueous waste treatment plant, such as urban wastewater treatment plants, where the pretreatment reactor inlet is connected to primary sludge conduction means generated in a first decanter, before that said conduction means in turn collect the secondary sludge from a second decanter and connect at its second end with a mixed sludge anaerobic digestion tank; and the outlet of the hydrolysis reactor is connected to conduits of primary sludge enriched in hydrolytic organisms inside the anaerobic digestion tank of mixed sludge.
    Thus, the invention thus covers in a preferred case a primary and secondary water treatment plant, with sludge line, comprising:
    - a primary treatment unit (8) and a primary decanter (9),
    connected to
    - a biological process tank (10) and a secondary decanter (11);
    - means for pumping primary sludge (12) originating in the decanter
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    primary (9) and secondary sludge pumping means (13) originating from the secondary decanter (11);
    - conduction and canalization means (14) of the primary and secondary sludge from the primary (9) and secondary (11) decanter, respectively, up to
    - an anaerobic biological digester (6) for the treatment and stabilization of sludge;
    which in turn comprises the pretreatment installation as described above, so that the sludge conduction means (14) comprise a valve (7) to separate a fraction of the primary sludge originating in the primary decanter (9 ) and directing said fraction to the interior of the biological pretreatment reactor (1) by pumping means (19); preferably, the installation comprises an intermediate reactor (15) for storing the primary sludge fraction after the valve (7) and before the pumping means (19); and from the outlet (5) of the biological pretreatment reactor (1), the enriched sludge is directed to the anaerobic digester (6) where the primary and secondary sludge meet, giving rise to the mixed sludge.
    Previously it has been specified that pretreatment can be applied to a process of hydrolysis of organic matter or, more broadly, to an industrial process of which hydrolysis, as a phase or as a stage, forms part; A preferred case covering the invention is an anaerobic biomass treatment process, in which hydrolysis constitutes the first phase of said treatment. A very common and preferred case for the properties of the waste that is generated and for the volume it represents of urban waste is the process of sludge treatment through anaerobic digestion in a secondary wastewater treatment plant or sewage treatment plant. However, the process to which biological pretreatment is applied is not only limited to the treatment of sewage sludge through anaerobic digestion, but it can also be applied to other anaerobic biomass treatment processes of which the hydrolysis reaction is part, which may also be: anaerobic membrane systems, anaerobic electrochemical cells or upflow anaerobic reactors (abbreviated UASB). Upflow Anaerobic Sludge Blanket), among the most common.
    Apart from the treatment of sewage sludge, the pretreatment method and the
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    Installation designed for this purpose are applicable to other industries, such as those mentioned above as a non-limiting example of application: paper industry (generation of cellulose waste with subsequent treatment), food industry (canned food, slaughterhouses, distilleries, etc.) with treatment of sludge and other production waste, biofuel producing industry in which the waste of the materials used to generate the biofuel is treated in situ, landfills in which all or part of the solid waste treatment or treatment is carried out in situ of contaminated soils through bioremediation.
    DESCRIPTION OF THE FIGURES
    FIGURE 1. Flow chart of the method of biological pretreatment of organic matter object of the present invention, applied to the treatment of a stream of primary sludge from primary decantation in wastewater treatment plants, which include a secondary treatment stage of said sludge by anaerobic digestion. The dashed line delimits in the figure the installation for biological pretreatment of the concentrated aqueous stream of organic matter, which are the primary sludge.
    (1) Biological pretreatment reactor
    (2) Reactor heating means (1)
    (3) Reactor agitation media (1)
    (4) Pumping means, such as a metering pump, at the outlet (5) of the reactor (1)
    (5) Exit of the biological pretreatment reactor (1) that directs the primary sludge enriched in hydrolytic organisms to the anaerobic sludge digestion tank (6)
    (6) Mixed sludge anaerobic digestion tank or reactor
    (7) Primary sludge inlet valve to the reactor (1) (or to an intermediate pretreatment reactor (15) in case of its presence)
    (8) Primary treatment unit of the treatment plant
    (9) Primary Decanter
    (10) Biological process tank
    (11) Secondary Decanter
    (12) Primary sludge pumping means from the outlet of the primary decanter (9) to the digestion tank (6)
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    (13) Secondary sludge pumping means from the outlet of the secondary decanter (11) to the digestion tank (6)
    (14) Means for conducting primary and secondary sludge to the digestion tank (6)
    (15) Intermediate storage tank of the primary sludge fraction after its deflection with the valve (7) and before being pumped to the hydrolysis reactor (1) by means of the metering pump (4)
    (16) Untreated wastewater stream
    (17) Treated wastewater stream
    (18) Stream of mixed treated sludge
    (19) Pumping means, such as a metering pump, of primary sludge to the reactor (1) from the intermediate tank (15) for storage of the fraction of primary sludge after its deviation with the valve (7).
    PREFERRED EMBODIMENT OF THE INVENTION
    A preferred case of the present invention is a method of biological pretreatment of organic matter and culture of organisms, specifically bacterial, according to the general description in which said components are found in the sludge from the primary decantation in a plant of wastewater treatment, and in such a way that said pretreatment is integrated into the wastewater treatment process itself, as one more stage that is after the primary treatment but which aims to improve the hydrolysis reaction that occurs during the process Anaerobic digestion of sludge.
    Figure 1 shows in more detail the method of biological pretreatment object of patent, the process of water purification and the sludge treatment line in which it is coupled and the facilities designed for this purpose.
    Conventional sewage plants mix the sludge generated in the primary phase, from a primary treatment unit (8) and a primary decanter (9), and the sludge generated in the secondary phase of wastewater treatment, from a biological process tank (10) and a secondary decanter (11), to form mixed sludge. Normally, these sludges are directed to a parallel water treatment line, where after collecting them by pumping (primary sludge pumping means (12) and secondary sludge pumping means (13) in
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    conduction and canalization (14), these mixed sludges are charged to an anaerobic biological digester (6) for treatment and stabilization. Since secondary sludge is highly stabilized, this hinders the proliferation of hydrolytic bacteria in the anaerobic digester, reducing the hydrolysis performance in anaerobic digestion.
    In the wastewater treatment plant in which the biological pretreatment method according to the present invention is applied, a fraction or almuot of the primary sludge is diverted, which is the current with organic matter to be treated by hydrolysis, said corresponding fraction 10% of the total mixed sludge (primary and secondary) to be treated in the anaerobic digester (6) of the treatment plant. In the example at hand, the composition of the primary sludge in terms of proteins, oils and fat and total and dissolved nutrients has been shown in Table 1. This fraction of primary sludge is diverted by the valve (7) when they are being driven said sludge through the pumping means (12) until the pretreatment facility; said valve (7) regulates the entry of the primary sludge into the tank depending on the needs of the process, and directs the sludge fraction into the reactor (1) by means of a metering pump (19). In a preferred case, the primary sludge diverted by the valve (7) in an intermediate storage tank (15) can also be maintained for a while before being directed to the reactor (1) by means of the metering pump (19). Said storage tank (15) protects the pretreatment reactor (1) from possible interruptions in the supply of primary sludge.
    Table 1. Composition of primary sludge (aqueous stream containing biodegradable organic matter) in the preferred embodiment of the invention
     Parameter  Concentration
     Protect  272.5 mg / L
     Oils and fats  0.51%
     Total Potassium  120.6 mg / kg
     Dissolved Potassium  73.5 mg / L
     Total Phosphorus  257 mg / kg
     Dissolved Phosphorus  77.95 mg / L
    The primary sludges inside the reactor (1) are kept homogenized by means of slow agitation (3), and are subjected to temperatures of 35 ° C (being
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    this temperature a non-limiting example) by means of heating (2). The hydraulic retention time is controlled by the metering pump (19) located at the inlet of the reactor (1) (or located between the intermediate tank (15) and the pretreatment tank (1) in the preferred embodiment).
    The volume of the fraction of deviated sludge (10% of the total mixed sludge volume produced in the treatment plant) and the hydraulic retention time inside the pretreatment reactor (1) allow to calculate the volume of said reactor (1) without specify additional data; Thus, in the case of operating an anaerobic digester (6) of the mixed sludge with a retention time of 20 days, the volume of said digester would be 20 times the total flow of mixed sludge to be treated, while the reactor volume (1) of pretreatment would be 0.1 times the total flow of mixed sludge to be treated. This gives an idea of the compactness of the pretreatment facility compared to the volume of the digester (6). This implies a low capital and operating cost of the system object of protection in this patent. Given the corrosive nature of the sludge and the culture temperature of the hydrolytic bacteria in the pretreatment, controlled by the heating means (2) (35 ° C), this pretreatment reactor (1) is constructed in stainless steel AISI316. To minimize heat losses and increase the efficiency of the heating means (2), the reactor (1) is completed with an external layer of heat-insulated with rock wool and aluminum sheet. On the other hand, the means (3) of agitation (slow), again at low revolutions (by slow agitation speed can be understood as that between 200-1000 revolutions per minute), facilitates the mixing of solids in the tank or reactor (1) so that there is adequate contact between the hydrolytic bacteria and the substrates (organic matter) of the sludge and that there is an adequate heat transfer to all points of the sludge, without thereby altering the possible flocculent structure of the influent. The heating means (2) must ensure that the reactor contents acquire a temperature of approximately 35 ° C (mesophilic range, included as a non-limiting example in this embodiment) regardless of the temperature of the primary sludge influent.
    A logic controller (not shown in the figure) incorporated into the installation allows the different equipment involved in the water treatment process to operate automatically, taking into account measurements of different parameters taken by probes (not shown in the figure) distributed throughout the process (mainly, a pH probe in the pretreatment reactor (1), although it can also include probes of
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    temperature or flow rate), verifying the appropriate operating conditions. The proper functioning of the hydrolysis process in the pretreatment reactor (1) is evidenced by the existence of a pH between 4 and 6 (usually 5, but which can range between the values of the aforementioned range). This automaton also allows you to store the data of the different probes distributed by the system, in order to study the optimal operation of it.
    One of the main innovations presented by the method object of the invention is the selection and growth of organisms that generate hydrolytic enzymes, specifically bacteria in this example, using concentrated currents (between 0.1 and 100 g / L of the total volume of current) of organic matter from the process itself. In this way, it is not necessary to use expensive culture broths or to carry out the external enrichment of said bacteria (selected and / or enriched in other processes). Specifically, it is demonstrated that by diverting part of the primary sludge (rich in organic matter) to a pretreatment method included in the sludge line and separated from the conventional water line of the depuration plant, enrichment of hydrolytic bacteria can be performed. This enrichment is favored by the imposition of operational parameters that drive the appearance of this type of groups of bacteria that produce hydrolytic enzymes, such as thermophilic and mesophilic temperature ranges and low retention times of solids in the biological pretreatment reactor. Thus, thanks to the low retention time values of solids used (between 24 and 48 hours), the size of the device for carrying out the pretreatment is very small and, therefore, the energy consumption of the system is minimal. The method is carried out with a compact pretreatment reactor, with low energy cost and low level of operational requirements. The installation designed for this purpose is, therefore, easy to include both in already operational plants and in new construction plants.
    The detailed description of the preferred realization of the pretreatment method presented in this section, applied to a wastewater treatment plant with anaerobic digestion, can also be applied to other sludge treatment processes with the relevant adaptations, such as anaerobic treatments of Type: anaerobic membrane systems, anaerobic bioelectrochemical cells, UASB or similar.
    权利要求:
    Claims (10)
    [1]
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    1. A method of biological pretreatment of biodegradable organic matter prior to an anaerobic hydrolysis process, comprising:
    - subject an aqueous stream containing the organic matter in a concentration between 0.1 and 100 g / L of the total volume of current to culture of organisms generating hydrolytic enzymes, under agitation and without external supply of nutrients during a retention time Hydraulic between 24 and 48 hours and in mesophilic regime at a temperature between 25 ° C and 45 ° C or thermophilic regime at a temperature between 45 ° C and 65 ° C, the organic matter being the substrate itself from which organisms are grown for enrichment in the aqueous stream,
    before subjecting the enriched aqueous stream to the biological hydrolysis process
    anaerobe.
    [2]
    2. The pretreatment method according to claim 1, wherein a fraction of the aqueous stream that represents a volume between 10% and 20% of the total volume to be hydrolyzed is deviated, is subjected to the culture of organisms and subsequently added to the rest of the the aqueous stream before being subjected to the biological process of anaerobic hydrolysis.
    [3]
    3. The pretreatment method according to any one of claims 1 or 2, wherein the aqueous stream to be pretreated originates from the industrial process itself in which said stream is subjected to the biological anaerobic hydrolysis process, such that the stream is subjects the culture of organisms at an intermediate stage between the stage where the current originates and the biological hydrolysis process where it is treated.
    [4]
    4. The pretreatment method of the preceding claim, wherein the industrial process is an urban wastewater purification process in a treatment plant comprising a sludge treatment line, a primary treatment of wastewater decantation, a secondary water treatment residual and an anaerobic digestion treatment of sludge of which the biological hydrolysis process is a part, so that the pretreatment method comprises:
    - divert all current or a fraction of primary sludge generated in the primary treatment of the inlet water to the treatment plant to cultivate and
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    enrich hydrolytic organisms; Y
    - subject the current or fraction of primary sludge diverted to cultivation of the hydrolytic organisms present in the sludge, under agitation and without external supply of nutrients;
    before pumping the stream or fraction of the primary sludge enriched in hydrolytic organisms to the anaerobic digestion process of a mixture formed by the primary sludge and secondary sludge generated in the secondary water treatment.
    [5]
    5. The method of pretreatment according to any one of the preceding claims, wherein the organisms generating hydrolytic enzymes grown in the stream are of the type that secretes enzymes from the family of hydrolases.
    [6]
    6. The pretreatment method according to the preceding claim, wherein the enzymes of the hydrolase family are selected from the group consisting of: amylases, proteases, cellulases and lipases.
    [7]
    7. An installation for the biological pretreatment of biodegradable organic matter prior to an anaerobic hydrolysis process according to the method defined in any one of claims 1 to 6, attachable to an industrial installation in which said current is generated and treated. organic matter to be pretreated, characterized in that it comprises:
    - a biological pretreatment reactor (1), which includes:
    or heating means (2) to select the organisms that generate hydrolytic enzymes to grow and favor their cultivation; or stirring means (3), to ensure that the content of the reactor (1) is properly mixed during the cultivation stage;
    - pumping means (4), located at the outlet (5) of the pretreatment reactor (1), which directs the enriched current in the pretreatment stage to a device (6) in which the hydrolysis process is carried out of the second stage, and which sets the hydraulic retention time of the biomass in the reactor (1).
    [8]
    8. The installation of the preceding claim, which is coupled to a primary and secondary water treatment plant that includes a sludge treatment line and comprising:
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    - a primary treatment unit (8) and a primary decanter (9), connected to
    - a biological process tank (10) and a secondary decanter (11);
    - primary sludge pumping means (12) originating in the primary decanter (9) and secondary sludge pumping means (13) originating in the secondary decanter (11);
    - conduction and canalization means (14) of the primary and secondary sludge from the primary (9) and secondary (11) decanter, respectively, up to
    - an anaerobic biological digester (6) for the treatment and stabilization of sludge;
    such that the sludge conduction means (14) comprise a valve (7) for separating a fraction of the primary sludge originating in the primary decanter (9) and directing said fraction to the interior of the biological pretreatment reactor (1) by pumping means (19); and the biological pretreatment reactor (1) comprises an outlet (5) of the enriched primary sludge, which is connected to the anaerobic digester (6) by means of the pumping means (4) where the primary and secondary sludge come together giving rise to the mixed sludge to hydrolyze.
    [9]
    9. The installation according to the previous revindication, which includes a logic controller and probes of heat, flow and / or pH to automatically operate the valves and means of conduction of the plant and regulate the deviation of the fraction of primary sludge to the reactor (1 ) and the exit of the enriched sludge from said reactor (1) to the sludge digestion tank (6).
    [10]
    10. The installation according to any one of claims 8 or 9, which includes an intermediate reactor (15) for storing the fraction of the primary sludge after being separated by the valve (7) from the current and before directing said fraction to the inside the pretreatment reactor (1) by means of pumping means (19).
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    同族专利:
    公开号 | 公开日
    ES2555358B1|2016-10-04|
    WO2016139377A1|2016-09-09|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO1996028400A1|1995-03-13|1996-09-19|Finney Jerry W|Biomass reduction and bioremediation processes and products|
    ES2176691T3|1996-02-21|2002-12-01|Europ Agence Spatiale|PROCEDURE AND INSTALLATION OF TREATMENT OF ORGANIC WASTE AND APPLICATIONS OF SUCH PROCEDURE.|
    SE440498B|1983-08-10|1985-08-05|Sca Development Ab|SET TO BIOLOGICALLY CLEAN THE WASTE WATER FROM MANUFACTURE OF PEROXID BLACK PASS|
    US6929744B2|2000-05-12|2005-08-16|United Utilites Plc|Sludge treatment at a mesophilic temperature|
    JP2005270862A|2004-03-25|2005-10-06|Sumitomo Heavy Ind Ltd|Anaerobic treatment apparatus|CN107804917A|2017-07-21|2018-03-16|中海油天津化工研究设计院有限公司|A kind of biological potentiating agent for being used to improve industrial wastewater biochemical system treatment effeciency|
    DE102019001127A1|2019-02-15|2020-08-20|Meri Environmental Solutions Gmbh|Method and device for anaerobic treatment of waste and / or process water with enzymes|
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