MXPA98002768A - Biosoportes porosos polimericos and its use in the biotratamiento of water currents of dese - Google Patents

Abstract

The present invention relates to porous biosporids for the support of microorganisms which are used in the biotreatment of an aqueous waste stream comprising a polymeric material and, optionally, fiber reinforcement, absorbent material and / or inorganic filler, wherein the biosupport has a specific gravity greater than the specific gravity of the water and pores of sufficient diameter to enable microorganisms to form colonies easily within the pores, a process for preparing them and procedures for biodegrading an aqueous waste stream containing organic contaminants using the biosporous pores

Description

POLYMERIC POROSOS BIOSOPORTES AND ITS USE IN THE BIOTRATAMIENTO OF WASTE WASTE CURRENTS DESCRIPTIVE MEMORY This invention relates to polymer porous biosports, particularly porous nylon biosports. In one aspect, this invention relates to the use of polymeric porous biosports in processes to biodegrade aqueous waste streams containing organic contaminants. In another aspect, this invention relates to the use of polymeric porous biosports in packed bed reactors and fluidized bed reactors for the biotreatment of aqueous waste streams. In a further aspect, this invention relates to the process for preparing polymeric porous biosports. The commercial use of immobilized bacteria (IBT) technology for the efficient biological treatment of chemical waste costs has been increasing. IBT uses highly selected chemical degradation bacteria in bioreactors designed to provide optimal conditions for microbial activity. In the IBT, biosports house bacteria that degrade toxic chemicals or pollutants from waste streams in environmentally safe products. This is usually done by flowing the waste stream through a reactor vessel containing the bacteria onto a biosupport medium. It has been demonstrated that the chemical degradation bacteria immobilized from the bioreactors achieve an exceptional performance for biotreatment of waste from the chemical industry. The use of IBT in fluidized bed reactors (FBRs) and packed bed reactors (PBRs) achieves high rates of chemical removal, tolerates severe conditions, survives inactivity, tolerates wave loads and produces lower levels of biological solids than conventional technologies for the treatment of waste. The biosubjects that are typically used in commercial scale bioreactors are predominantly sand, granular activated carbon particles (GAC) and porous inorganic particles such as diatomaceous earth, aluminum oxide and concreted glass. Although these biosols, also known as bioachargers, are commercially available and have been well tested as supports for chemical degradation bacteria, they have certain disadvantages. GACs and inorganic biosols are expensive and experience attrition of 5 to 20% per year. In addition, the removal of excess biomass from these biosubjects is problematic, because their high density and fragility make vigorous backflushing or mechanical separation of biomass difficult. Sand is producible and non-brittle, but requires a significantly longer period for microbial colonization (slower onset), and lacks the advantage of chemical adsorption as a complementary mechanism of removal. In addition, microorganisms in sand are more susceptible to failure in their performance, and recover slowly after physical or chemical disturbances occur. Lodaya et al. (U.S. Patent No. 5,403,487) has described the use of microporous synthetic resinous materials, including nylon, as bioslides for use in the treatment of aqueous waste streams in aerated packed bed reactors. The microporous synthetic resinous materials of Lodaya and others have a density less than the density of the water, that is, they float in the reactor, and therefore require a screen to hold the resin particles in place. The density of the microporous synthetic resinous materials of Lodaya and others creates the significant problem of not allowing to handle the biological corrosion and control of biomass in the packed bed reactor. The packed bed reactor of Lodaya and others also requires the use of a recirculation stream. In addition, Lodaya and other synthetic microporous resinous materials can not be used in fluidized bed reactors because they float. ThusA biostating material that solves the problems of commercially available biosystems and materials such as those described in Lodaya and others would be highly desirable. It has now been found that the porous polymer biosports of the invention solve the problems described above. Specifically, the porous polymer biosports of the invention have the following advantages: (1) high porosity, which allows a fast and dense colonization by the inoculated bacteria, (2) large pore sizes and open structure, which promote higher growth levels of the microorganisms within the biosport and that result in a greater tolerance to disturbances, less loss of biomass during fluidization, and superior general performance, (3) high physical resistance that eliminates friction, (4) inert to most of the chemical compounds and waste streams, (5) density slightly higher than water density, eliminating the problems of Lodaya and others and allowing a simple fluidization effective in costs through the injection of air to control the biomass in PBRs, (6) large rigidity, which provides good abrasion of excess biomass during fluidization, (7) chemical biodegradation regimes equal to, or and exceed, the commercially available biosports, and (8) production procedure that allows flexibility in size, density, porosity and composition of the biosports. The polymeric porous biosports of the invention also have the advantage of using waste polymers or recirculating polymers as the supply material. This use of waste or recirculating polymers is an environmentally friendly process that results in recirculation and waste reduction. An object of the invention is to provide a porous polymer biosupport having a density greater than the density of water, and open pores of sufficient diameter to allow microorganisms to rapidly colonize the interior of the pores. Another object of the invention is to provide a polymer porous biostock that is essentially free of friction during the operation of a fluidized bed or packed bed bioreactor. Yet another object of the invention is to provide a polymer porous biosupport that is relatively inexpensive. Yet another object of the invention is to provide a porous polymer biostock to which an absorbent material can be incorporated that can be used as a complementary removal mechanism to improve biodegradation and maintain a high quality effluent, and fiber reinforcement for improved strength. In accordance with the invention, a porous biospor is provided for the support of microorganisms which is used in the biotreatment of an aqueous waste stream, comprising a polymeric material comprising a thermoplastic polymer and, optionally, fiber reinforcement, adsorbent material and / or inorganic filler, where the biosupport has a specific gravity greater than the specific gravity of the water, and pores of sufficient diameter to allow the microorganisms to colonize the interior of the pores.

In accordance further with the invention, there is provided a method for biodegrading an aqueous waste stream containing organic contaminants, comprising inoculating a bed of particles of the biosport of the invention with an inoculum of a culture of microorganisms capable of biodegrading the organic contaminants, and contacting the aqueous waste stream containing the organic contaminants with the microorganisms of the biosporum for a sufficient time to degrade the organic contaminants. In one embodiment of the invention, the process is carried out in a packed bed reactor. In another embodiment of the invention, the process is carried out in a fluidized bed reactor. In accordance still more with the invention, there is provided a process for preparing the porous biostat of the invention, comprising extruding in a ventless extruder a composition comprising a polymeric material comprising nylon and, optionally, fiber reinforcement and / or adsorbent material, wherein the composition being extruded has a moisture content of about 0.1 to about 7% by weight, and pelletizing the extruder product of the extruder. Figure 1 is a plot of pore volume increase (measured as increased mercury intrusion in pores of specific pore sizes at various pressures during mercury intrusion porosimetry analysis) against pore diameter for porous biosporum of R533 nylon of the invention (indicated by dark squares), comparatively with two conventional bioslots, that is, beds of diatomaceous earth (indicated by dark triangles) and activated coconut charcoal (indicated by light squares). Each data point represents the pore volume for pores that vary in size from the plotted value, to the next lower plotted value. Figure 2 is a graph of the biodegradation of p-nor rofenol at high chemical loading by PNP1 of Pseudomonas sp on the porous biosporum of nylon R533 in a PBR. Figure 3 is a graph of the biodegradation of p-nitrophenol at high flow rates by PNP1 of Pseudomonas sp on the porous biosporum of nylon R533 in a PBR with an internal diameter of 8.9 cm. Figure 4 is a graph of the biodegradation of p-nitrophenol at high flow velocities by PNP1 of Pseudomonas sp on the porous biosporum of nylon R533 in a PBR with an internal diameter of 5.4 cm. Figures 5A and 5B are longitudinal surface views of the porous biosoporte of nylon R533 at two different magnifications. Figures 6A and 6B are longitudinal cross-sectional views of the porous biosoporte of nylon R533 at two different magnifications. Figure 7 is an end view of the porous biosoporte of nylon R533. A first embodiment of the invention relates to a porous biosporum for supporting microorganisms for the biotreatment of an aqueous waste stream containing organic contaminants, and comprising (a) from 40 to 100% by weight of a polymeric material comprising a polymer selected from the group consisting of nylon, thermoplastic polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polysulfone, polyolefin, polyvinyl chloride, polycarbonate, polyimide, polyether ether ketone, polyphenylene sulfide, cellulose ester plastics, polyvinyl butyral, styrenic polymers, rigid thermoplastic polyurethanes, and mixtures thereof, (b) from 0 to 60% by weight of a fiber reinforcement, (c) from 0 to 60% by weight of a material adsorbent, and (d) from 0 to 40% by weight of an inorganic filler, wherein the sum of the amounts of fiber reinforcement, adsorbent material and inorganic filler in the biosupport is 0 to 60% by weight, and the biosupport has a specific gravity greater than the specific gravity of the water, and pores of sufficient diameter to allow microorganisms to colonize the interior of the pores. The preferred polymeric materials that are used in the biosport of the invention comprise a polymer selected from the group consisting of nylon, thermoplastic polyester, ethylene-vinyl alcohol copolymer, polysulfone, polyvinyl chloride, polycarbonate, polyimide, polyether ether ketone, polyphenylene sulfide, cellulose ester plastics, polyvinyl butyral, styrenic polymers, rigid thermoplastic polyurethanes, and mixtures of the same, because the polymers have specific gravities greater than 1.0. The most preferred polymeric materials used in the biosport of the invention comprise a polymer selected from the group consisting of nylon, thermoplastic polyester, and mixtures thereof, due to the availability of the recirculation or waste material. Nylon is the most preferred polymer used in the polymeric materials of the invention due to the excellent results obtained with it. In addition to the polymer, the polymeric material of the invention may also contain polymers other than those mentioned above and fillers, particularly inorganic fillers. When a polymer with a specific gravity of less than 1.0 is used, for example a polyolefin, the polymeric material must contain other materials, or the biosensor must contain an adsorbent material, a fiber reinforcement and / or an inorganic filler, so that the Specific gravity of the polymeric material is greater than 1.0. For example, if a polyolefin is used, then an additional polymer having a specific gravity greater than 1.0 or an adsorbent material, a fiber reinforcement and / or an inorganic filler should also be used. Suitable nylon polymers that are used in the biosport include any readily available nylon, in particular nylon 6, nylon 6.6, nylon 4.6, nylon 11, nylon 12, nylon 6.9, nylon 6.10, and mixtures or copolymers thereof. The currently preferred nylon polymers are nylon 6 and nylon 6.6, due to their cost and availability. Of particular interest for use in the bioslides of the invention are nylon waste materials which include, but are not limited to, manufacturing debris, special products, and cuts from the manufacture of nylon mats. In addition, the nylon that is used in the invention can be derived from used nylon carpets which are obtained in accordance with the process described in the U.S.A. No. 5,294,384, which is incorporated herein by reference. The nylon derived from used carpets, which is processed without separating from the carpet in its component parts, will also contain at least one polyolefin (derived from the reinforcement), a styrene-butadiene rubber (SBR) (used as an adhesive) and, optionally, , an inorganic filler. The nylon that is used in the invention can also be derived from other recirculated nylon products, such as molded nylon objects that can be reprocessed. Such nylon products may contain fiber reinforcement and inorganic fillers. The use of waste or recirculating nylon as a source of nylon in the bioslides of the invention is an environmentally favorable use of waste material that would otherwise be discarded, such as by the formation of embankments. Suitable thermoplastic polyesters that are used in the biospor are readily available and include the polymers described in Encyclopedia of Polvmer Science and Engineering, 2nd ed., Vol. 1-75 and 217-256 (1988), which is incorporated herein by reference. Particularly useful thermoplastic polyesters include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). In particular, waste and recirculating PET and PBT, which include material derived from used polyester carpets, are suitable sources of polyester material. The polyester derived from used carpets that is processed without separating from the carpet into its component parts will also contain material derived from the reinforcement, for example, a polyolefin, an adhesive such as SBR and, optionally, an inorganic filler. The polyvinyl chloride that is used in the biosupport may be a homopolymer, or it may be a copolymer of vinyl chloride and vinyl acetate typically containing from 85 to 97% of the chloride monomer. The polyolefins used in the biosport include ethylene and propylene homopolymers, and copolymers of ethylene and propylene with another olefin, for example, ethylene / propylene and ethylene / hexene copolymers. The polypropylene carpets used are a suitable source of polypropylene.

The polypropylene derived from used carpets which is processed without separating from the carpet into its component parts will also contain material derived from the reinforcement, an adhesive such as SBR and, optionally, an inorganic filler. The polysulfones used in the biosupport are readily available, and include polymers described in Encyclopedia of Polymer Science and Engineering, 2a. ed., Vol. 13, pp. 196-211 (1988), which is incorporated herein by reference. The polysulfones that are used in the biosports of the invention include polyethersulfones. The polycarbonates that are used in the biosport are readily available, and include polymers described in Encyclopedia of Polymer Science and Engineering, 2a. ed., Vol. 11, pp. 648-718 (1988), which is incorporated herein by reference. The polyimides that are used in the biosporum are readily available, and include polymers described in Encyclopedia of Polymer Science and Engineering, 2a. ed., Vol. 12, pp. 364-383 (1988), which is incorporated herein by reference. The polyimides that are used in the biosports of the invention include polyetherimides. The polyether ether ketones used in the biosupport are readily available, and include polymers described in Encyclopedia of Polymer Science and Engineering, 2a. ed. , Vol. 12, pp. 313-320 (1988), which is incorporated herein by reference. The polyphenylene sulfide used in the biosupport is readily available, and includes polymers described in Encyclopedia of Polymer Science and Engineering (Encyclopedia of Science and Engineering of Polymers), 2a. ed. , Vol. 11, pp. 531-557 (1988), which is incorporated herein by reference. The cellulose ester plastics that are used in the biosporum are readily available, and include polymers described in Encyclopedia of Polymer Science and Engineering (Encyclopedia of Science and Engineering of Polymers), 2a. ed. , Vol. 3, pp. 181-200 (1988), which is incorporated herein by reference. Particularly useful cellulose ester plastics are cellulose acetate, cellulose acetate butyrate and cellulose acetate propionate. The polyvinyl butyral materials used in the biosport are commercially available and have a hydroxyl content expressed as a percentage of polyvinyl alcohol of up to 20%. The ethylene-vinyl acetate and ethylene-vinyl alcohol copolymers which are used in the biosports of the invention are commercially available. Styrenic polymers, as used in the present invention, include polystyrene, rubber modified polystyrene, or high impact polystyrene (HIPS), acrylonitrile-styrene copolymers (SAN), rubber-modified acrylonitrile-styrene copolymers (ABS), styrene-maleic anhydride copolymers (SMA), styrene-methyl methacrylate copolymers and acrylate-styrene-acrylonitrile (ASA) copolymers. Styrenic polymers that are used in the biosporum are readily available, and include polymers described in Encyclopedia of Polymer Science and Engineering, 2a. ed., Vol. 16, pp. 62-97, and Vol. 1, pp 388-426 and 452-464 (1988), which is incorporated herein by reference. Suitable polyurethane materials that are used in the biosport are commercially available and are rigid thermoplastic materials that are capable of producing open cell structures. Suitable inorganic fillers that are used in the biosports of the invention include carbonates such as calcium carbonate and barium carbonate, silicates such as clay (kaolin), calcium silicate, mica, talc and olastonite, sulfates such as calcium sulfate and barium sulfate, and oxides such as silicon dioxide and titanium dioxide. The presently preferred fillers are calcium carbonate, calcium sulfate, kaolin, mica, talc and wollastonite. The amount of polymeric material present in the bioslots of the invention is widely from 40 to 100% by weight of the biosupport. The preferred biosols of the invention contain from 40 to 80% by weight of polymeric material, the rest being fiber reinforcement, adsorbent material and / or inorganic filler. It is better preferred that the biosports of the invention contain at least some fiber reinforcement to improve the physical resistance of the biosupport. It is currently preferred that the polymeric material consist essentially of nylon. If the polymeric material contains other components, the amount of nylon present is from about 35 to about 95% by weight, preferably about 40 to about 85% by weight, of the polymeric material. When the nylon source is used carpet, which typically contains an inorganic filler in the SBR adhesive used, the polymeric material comprises from 35 to 67% by weight of nylon, from 8 to 21% by weight of polyolefin, from 5 to 29 % of SBR and 10 to 40% by weight of inorganic filler. The fiber reinforcement used in the bioslides of the invention are fibers selected from the group consisting of glass, carbon, aramid, inorganic fiber-forming material selected from aluminum oxide, silica, boron, boron nitride, boron carbide, silicon carbide or aluminosilicate, and mixtures thereof. The fiber reinforcement currently preferred is glass fiber or carbon fiber because of its cost, performance and availability, fiberglass being the most preferred. The preferred form of fiber reinforcement is shredded fibers. The adsorbent material that is used in the biosports of the invention is selected from the group consisting of carbon (including charcoal, activated carbon, graphite and carbon black), ion exchange resins, zeolites, and mixtures thereof. The currently preferred adsorbent material is carbon, specifically charcoal or activated carbon. The amount of fiber reinforcement present in the bioslides of the invention is broadly from 0 to 60% by weight of the biostock, preferably about 5 to about 50% by weight, and more preferably about 15 to about 40% by weight. The amount of adsorbent material present in the bioslides of the invention is broadly from 0 to 60% by weight of the biostock, preferably from about 2 to about 50% by weight, and more preferably from about 3 to about 30% by weight. The amount of inorganic filler present in the biosports of the invention is broadly from 0 to 40% by weight of the biostock, preferably from about 5 to about 30% by weight, and more preferably from about 10 to about 25% by weight. The total amount of fiber reinforcement, adsorbent material and inorganic filler in the biosports of the invention should not exceed 60% by weight. The polymeric material of the bioslides of the invention may further comprise an additive polymer material, wherein the additive material contains one or more of fiber reinforcement, adsorbent material, inorganic fillers and polymeric material, in addition to a non-plastic or rubber material. suitable as the primary polymeric material of the bio-bearing. Examples of plastic or rubber materials that may be present in the additive polymeric material, but which are not suitable as the primary polymeric material of the biostatic, include polybutadiene and elastic copolymers thereof, for example styrene-butadiene rubber (SBR), acrylic polymers, resins based on polyphenylene oxide (PPO), and fiberglass reinforced plastics, particularly recirculated material of automobiles containing, for example, entangled polyesters. A particularly suitable source of an elastic polymeric additive are recirculated used tires. The used tires contain, in addition to a rubber material such as SBR, materials that include carbon black, fiber reinforcement and polyester fibers. The additive polymer material optionally contains other additives such as antioxidants, stabilizers, coupling agents, etc., which are not classified as fiber reinforcement, adsorbent material or inorganic fillers. The percentage of plastic or rubber material present in the polymeric additive will determine the level of polymeric additive that may be incorporated in the biosupport. The upper limit of the amount of polymeric additive is that amount above which it will cause problems to produce the biosupport, and will depend on the specific plastic or rubber material and its rheological properties and other relevant properties. In general, the upper limit will be that amount in which the amount of the plastic or rubber material, plus the amount of any additive other than the fiber reinforcement, adsorbent material and inorganic filler present, is up to about 30% by weight, preferably up to about 15% by weight, and more preferably about 10% by weight of the biosupport. Acrylic polymers, as used in the present invention, include polymethyl methacrylate, rubber modified polymethyl methacrylate, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate and polyethyl methacrylate. Resins based on polyphenylene oxide, particularly mixtures of polyphenylene oxide with impact polystyrene, such as HIPS, can be obtained easily. The polymeric materials or additive polymeric materials used in the bioslots of the invention can not contain an amount of any stabilizer, antioxidant, etc., which when incorporated into the biostant would prevent it from being inoculated, or which will sustain microorganisms when it is used. in immobilized bioreactors. The bioslides of the invention are substantially open cell materials, that is, they have open pores, and have a specific gravity greater than the specific gravity of the water. The specific gravity of the biosporum must be quite large, so that the inoculated biostatic particles are not floating in the bioreactor of immobilized bacteria during normal operation or during aeration or fluidization used to control the biomass. Preferably, the specific gravity of the biosports of the invention is greater than 1.1. The specific gravity of the biosporum can be easily controlled by varying the biostatic composition, ie, the type and amount of polymeric material, fiber reinforcement and adsorbent material, and the process conditions under which bioslides are extruded, for example, water concentration or foaming agent. The specific gravity of the biosports of the invention allows the biosports to be used in fluidized bed and packed bed reactors. In the FBRs, the specific gravity of the biostatic particles allows the particles of the biosount to be fluidized during the operation. In the PBRs, the specific gravity of the biostatic particles allows the biosoport particles to mix sufficiently to control the biomass in the reactor using air injection. The specific gravity of the biosports of the invention is controlled, so that the specific gravity is less than the specific gravity at which it is no longer practical to fluidize or sufficiently mix a bed of the biostatic particles. It is currently preferred that the specific gravity of the biostatic particles be less than about 3., more preferably less than about 2. The biosports of the invention have pores of sufficient diameter to allow microorganisms to colonize the interior of the pores. Typical microorganisms have a diameter or thickness of 0.5 to 5 μm, such as approximately 1 to 2 μm, and a length of 2 to 4 μm. Therefore, biosporids that have pore sizes greater than the size of microorganisms are particularly useful. In general, microorganisms require a pore diameter of at least 4μm to access the pore. The biosubjects of the invention were analyzed to determine the pore sizes using porosimetry by intrusion of mercury and scanning electron microscopy. Mercury intrusion porosimetry is used to determine pore sizes in the scale from lμm to approximately 390μm. Scanning electron microscopy is used to qualitatively determine pore sizes greater than 390μm. It is clear from the analysis of the micrographs (see Example 6), that the biosports of the invention can be produced with external pore sizes, ie, pore openings, up to 700μm, and internal openings up to 3.9mm in length. The bioslides of the invention are particularly useful because they have external pores within the range of lμm to approximately 700μm, preferably within the range of lμm to approximately 420μm, and internal openings typically up to approximately 800 to approximately 1200μm in length. As the scale of pore sizes is used in the present invention, the biosports of the invention may have pores that are less than 1 μm, and larger than those described above. For pore sizes between 1 μm and 390 μm, the biosports of the invention have an average pore diameter (based on volume) of at least about 40 μm, preferably at least about 50 μm, and more preferably at least about 70 μm. The actual average pore diameter of the biosports of the invention will typically be higher, due to the number of pores in diameter greater than 390μm. The bioslides of the invention can also be characterized by the cumulative pore volume and the cumulative pore area. The cumulative pore volume or pore volume (for pore sizes greater than about 1 μm and up to 390 μm) of the biostatic particles is preferably at least 0.2, more preferably at least about 0.3, and even more preferably at least about 0.3. about 0.3 to about 1.0 mL / g of the biosupport. The cumulative pore area or pore area (for pore sizes greater than about 1 μm and up to 390 μm) of the biostatic particles is preferably at least 0.025, more preferably at least 0.03 m 2 / g of the biosupport. As in the case of pore diameter, the actual cumulative pore volume and the cumulative pore area will typically be higher due to the number of pores in diameter greater than 390μm. A second embodiment of the invention relates to a process for biodegrading an aqueous waste stream containing organic contaminants, and comprising inoculating a bed of particles from a biosporum with an inoculum of a culture of microorganisms capable of aerobic biodegradation of organic contaminants, and contacting the aqueous waste stream containing the organic contaminants with the microorganisms of the biosporum for a sufficient time to degrade the organic contaminants; where the biosoporte is as defined above. The biodegradation process can be carried out in any suitable bioreactor of immobilized bacteria, particularly a fluidized bed or packed bed reactor. Suitable bioreactors of immobilized bacteria also include in situ biotreatment zones useful in in situ bioremediation procedures. An example of said in situ bioremediation process is described in the patent of E.U.A. No. 5,398,756, which is incorporated herein by reference. Biodegradation can be carried out aerobically or anaerobically, depending on the specific organic contaminants and the selected microorganisms. It is currently preferred that the process be carried out aerobically due to the utility of aerobic biodegradation for a wide variety of organic contaminants. A third embodiment of the invention relates to a method for treating an aqueous waste stream containing organic contaminants, and comprising passing the waste water stream through a packed bed reactor, the packed bed reactor containing a bed packaging of biostatic particles that support microorganisms capable of biodegrading organic pollutants, by means of a process in which the aqueous waste stream is oxygenated by introducing oxygen into the feed end of the packed bed reactor, in order to subject the organic contaminants to the current water from oxygenated waste to aerobic biodegradation and to produce a purified aqueous effluent; where the biosoporte is as defined above. The process can be carried out in conventional packed bed reactors of immobilized bacteria which are well known to those skilled in the art, such as that described in Heitkamp et al., "Biodegradation of p-Nitrophenol in an Aqueous Waste Stream by Immobilized Bacteria ", Appl. Environ. Microbiol .. October 1990, pp. 2967-2973, which is incorporated herein by reference. A fourth embodiment of the invention relates to a method for treating an aqueous waste stream containing organic contaminants, and comprising passing the wastewater stream through a fluidized bed reactor, the fluidized bed reactor including a line of recirculation and containing a fluidized bed of particles of the biosporum that support microorganisms capable of biodegrading the organic pollutants, by means of a process in which the feed to the fluidized-bed reactor is oxygenated, in order to subject the organic contaminants of the oxygenated feed to aerobic biodegradation , and to produce a purified aqueous effluent, wherein the feed for the fluidized bed reactor comprises a recirculating stream of a portion of the effluent and the waste aqueous stream, and the feed is oxygenated by dissolving oxygen in the recirculation stream, the aqueous stream of the feed or the feed for the fluidized bed reactor at a point external to the fluidized bed; where the biosoporte is as defined above. The process can be carried out in conventional fluidized bed reactors of immobilized bacteria which are well known to those skilled in the art, such as that described in Edwards et al., "Laboratory scale evaluation of aerobic fluidized reactors for the biotreatment of a synthetic, high-strength chemical industry waste stream ", Water Environ. Res. Vol. 66, No. 1, pp. 70-83 (January / February 1994) and the patent of E.U.A. No. 5,540,840, issued July 30, 1996, which are incorporated herein by reference. A fifth embodiment of the invention relates to a process for preparing the porous biosupport of the invention, which comprises extruding in a non-vent extruder a composition comprising: (a) from 40 to 100% by weight of a polymeric material comprising nylon , (b) from 0 to 60% by weight of a fiber reinforcement, (c) from 0 to 60% by weight of an adsorbent material, and (d) from 0 to 40% by weight of an inorganic filler, the sum of the amounts of fiber reinforcement, adsorbent material and inorganic filler in the biostock is from 0 to 60% by weight, in the presence of about 0.2 to about 5% by weight (based on the weight of the total composition) of water , a foaming agent or mixtures thereof, and transforming the extruder product of the extruder into pellets; where the bio-bearing has a specific gravity greater than the specific gravity of the water and, pores of sufficient diameter to allow the microorganisms to colonize the interior of the pores. The water and / or the foaming agent present in the composition being extruded is broadly from about 0.1 to about 7, preferably from about 0.1 to about 5, more preferably from about 0.1 to about 2, and most preferably from about 0.2 to about 1% by weight, based on the weight of the total composition that is being extruded. The compound present in the composition which is being extruded, which causes foaming and which results in the formation of the porous biosupport is water, a foaming agent or a mixture of water and a foaming agent. The water and / or foaming agent added to the composition being extruded is selected to achieve the porosity and pore size distribution desired for the biosupport that is being produced, and will depend on the particular polymeric material that is being extruded. . The selection of the water and / or foaming agent that allows to achieve the desired level of steam production or foaming in the extruder will be readily apparent to those skilled in the art. The currently preferred material that is used to produce the porous biosports of the invention is water due to its efficiency and economy. Foaming agents, or blowing agents, become gas during the process, that is, during the extrusion, and the gas thus produced creates the porous structure of the biosupport. This structure is determined by the type and amount of the foaming agent selected, the type of gas produced and its solubility, the preparation / extrusion method used, the temperatures and pressures used in the process, and the viscosity of the molten bath of the product. material that is being extruded. In the extrusion process that allows to prepare the porous biosports of the invention, the water functions as a foaming agent. Examples of suitable foaming agents include, but are not limited to, fluorinated aliphatic hydrocarbons such as chlorofluorocarbons, 1,1-azobisformamide (ABFA), p, p'-oxybis (benzenesulfonyl hydrazide) (OBSH), p-toluenesulfonyl is icarbazide ( TSSC), trihydrazine triazine (THT), 5-phenyltetrazole (5-PT), sodium bicarbonate, and mixtures thereof. The composition to be extruded is prepared by mixing the composition in any conventional polymer preparation mixer. The temperature and pressure used in the extruder will depend on the particular material that is being extruded, and will be readily apparent to those skilled in the art. In addition, the type and size of extruder used will be readily apparent to those skilled in the art. An individual worm extruder is currently preferred. The biosport pellets produced can have any size and shape that allows them to be randomly packed in a packed bed reactor, or fluidized in a fluidized bed reactor. The cross section of the pellets of the biosport will have the shape of the particular die used during the extrusion, for example, circular, rectangular, square, etc. The length of the pellets of the biosport is determined by how the extrusion product is cut or shredded . The pellets of the biosport preferably have an effective diameter and / or length, so that they have a larger convenient size than a No. 10 sieve (series of US -ASTM E-ll-70, 2.0 mm sieves), preferably greater than a No. 7 sieve (USA sieve series -ASTM E-ll-70, 2.8 mm). The maximum size of the biostatic pellets is that size which prevents the pellets from being adequately fluidized or mixed in a bioreactor, or having a particle surface area: pore area ratio such that the pores are ineffective in increasing the Biodegradation in the bioreactor. A typical form for the biosports of the invention is cylindrical. For example, an extruded porous biospor typical of the invention will have a cylindrical shape with a diameter of about 0.25 to about 1.3 cm, preferably about 0.25 to about 0.6 cm and a length of about 0.6 cm to about 1.3 cm.

EXAMPLES The chemical compounds used in the examples are the following. P-Nitrophenol (PNP) having a purity of more than 99% was obtained from Aldrich Chemical Co. (Milwaukee, Wl). Agar for normal plaque counting (SPC) and plate plating agar obtained from Difco Laboratories (Detroit, MI) were obtained. The yeast extract was obtained from Sigma Chemical Company (St. Louis, MO). Trypticase soy agar was obtained from Becton Dickinson and Company (Cockeysville, MD). The inorganic chemical compounds were purchased from Fisher Scientific (Fair Lawn, NJ). The nylon was obtained from the Monsanto Company. Diatomaceous earth (type R635) was obtained from Manville Company. Activated coconut charcoal was obtained from Charcoal Filtration Co. (Inglewood, CA). The concentrations of PNP were determined spectrophotometrically by measuring the optical absorbance at 414 nm. A linear relationship was observed between the absorbance of PNP and its concentrations varying from 0.5 to 35 mg / L. The pH of the samples and standards was adjusted to above 8.0 using identical volumes of concentrated sodium hydroxide (2.5 N) to ensure complete chromophore formation by PNP. Absorbance of samples and standards was measured in 96-well microtiter plates using a Titertek Multiskan MCC / 340 automatic plate reader (Flow Laboratories, Mclean, VA). Effluent samples were collected with a pipette from each column, and filtered through a 0.45μm Acrodisc 25 syringe filter (Gelman Sciences, Ann Arbor, MI) before performing the chemical analysis. The porosity analyzes were carried out as follows. The pore size distribution for porous biosporids was determined by mercury intrusion porosimetry. The samples were placed in a penetrometer test cell, which was then evacuated and filled with mercury. The diameter of the pores was calculated from the pressure required to force mercury into the particles of the porous biosupport. This calculation of the pore diameter assumes a circular cross section for the pores. The samples were analyzed over the entire scale of the instrument, ie 390 μm in diameter, up to 30 Angstroms in diameter. Scanning electron micrographs were used to determine the presence of pore sizes greater than 390 μm. Samples for scanning electron microscopy (SEM) were rinsed in a pH regulated solution (0.1 M sodium cacodylate, pH = 7.4), fixed in 2% glutaraldehyde, and stored in a refrigerator until they were analyzed. . The fixed samples were warmed to room temperature, rinsed in sodium cacodylate pH regulator solution, and fixed for 1 hour in 2% osmium tetroxide buffered at pH. Then, the samples were rinsed in sodium cacodylate pH buffer solution, dehydrated using a series of ethanol (50%, 70%, 80%, 90%, 95% and 100%), and dried to the point critical using liquid carbon dioxide. The dried samples were placed on slides for SEM Al with double adhesive tape, and coated with Au / Pd using the Polaron E5100 coating unit for electron beam conductivity. SEM analyzes and micrographs were obtained using a JEOL 840 scanning electron microscope.

EXAMPLE 1 The following porous biosports have been prepared in accordance with the process of the invention. A porous biospore designated R533 was prepared by mixing a composition containing 67% by weight of nylon 6.6 (VydyneR21 from Monsanto Company) and 33% by weight of shredded glass fibers of 0.32 cm in length (Certainteed 93B glass fiber) using a twin shell cone mixer. The nylon had a moisture content of 0.3 to 0.5% by weight, that is, it contained 0.3 to 0.5% by weight of water. The mixture was combined using a 24/1 L / D vent-free extruder of 3.8 cm in diameter at a temperature of about 285 ° C (barrel extruder temperatures were adjusted over a decreasing profile of 295 to 280 ° C). The extrusion product was tempered in a water bath and transformed into pellets. A porous biostat designated as 740FG was prepared in accordance with the method used to prepare the R533 biostock, except that the nylon was a small fragment of nylon 6.6 containing finishing oils, and the extruder was a single worm extruder without vent 24/1 L / D of 3.8 cm in diameter. The small fragment of nylon 6.6 was produced by crushing nylon 6.6 fibers (Monsanto Company) in sections of 0.16 to 0.32 cm, and making them pass through a Pall an densifier (Pias agglomerator). In this procedure, the nylon fibers were melted by frictional heat, and passed through a die to obtain the final product. A porous biosporum designated 744FG was prepared in accordance with the method used to prepare the 740FG biostock, except that the nylon was a small fragment of nylon 6.6 without finishing oils. The biosubjects R533, 740FG and 744FG were analyzed using mercury intrusion porosimetry to determine the pore size distribution. In addition, the consolidated global density of the biosobiles was determined. The results are set forth later in Table I. In addition, a packed bed of 122 (30.5 cm) of biosport R533 submerged in water was completely fluidized by injection with air at the bottom of an ID column of 3.52 (8.9 cm) indicating that Periodic fluidization to remove excess microbial biomass could be carried out with air injection, unlike more expensive and difficult hydraulic mixing and re-flooding.

TABLE 1 Vol. of Diameter Area 8 Scale * Poor density of poo of global pore accum. acu. p romedio Biosopo rte mL / g m2 and ym g / l R533 0.5 0.036 83.5 3.390 323.4 740 FG 0.38 0.030 72.2 2.390 352.2 744 FG 0.29 0.30 59.1 1.390 384.2 * Determined by mercury intrusion porosimetry where the maximum measurable pore size is 390μm.

EXAMPLE 2 The following additional porous biosports have been prepared according to the process of the invention. A porous biosporum designated R400G was prepared by mixing calcined clay (Englehard Corp., Satintone # 5) and a nylon 6 / 6,6 random copolymer (Monsanto Company, 10.5% by weight of nylon 6 and 89.5% by weight of nylon 6, 6). This mixture was combined by high density mixing in a Farrel Continuous Mixer. This mineral reinforced product was then mixed with shredded glass fibers (described in Example 1) using a twin shell cone mixer (63.5 wt% nylon, 20 wt% clay and 16.5 wt% glass fiber) ). The nylon contained 0.9% by weight of water. The mixture was combined using a single unvented ventilator worm of 1.52 (3.8 cm), 24/1 L / D at a temperature of 285 ° C. The extrudate material was extinguished in a water bath and pelleted. A porous biosporum designated R400G-01 was prepared according to the method used for the biostock R400G except that the composition also contained 0.2 wt.% Of carbon black (the carbon black was charged by adding 0.6 wt.% Of a black concentrate). of prepared smoke containing 34% by weight of carbon black Cabot XC-72 in nylon 6 obtained from Custom Resins Incorporated (CRI) A packed bed of 122 (30.5 cm) porous biosports R400G and R400G-01 were each submerged in water at the bottom of an ID column of 3.52 (8.9 cm) and air fluidization was attempted, neither the R400G bed nor the R400G-01 bed were fluidized or mixed at the air injection speed that mixed thoroughly with the R533 biosoporte. The low-amplification light microscopy of the samples indicated that while the R400G and the R400G-01 were porous, the R533 was more porous than the R400G or R400G-01. It is expected that the R400G and R400G-01 could be fluidized at a speed of injection of air higher than that used for the R533.

EXAMPLE 3 The following additional porous biosports containing fiber reinforcement and adsorbent material were prepared according to the method of the invention. A porous biosum designated T-4198 was prepared from nylon fragments 6, 6 (example 1) and 3% by weight of carbon black with 25% by weight glass fiber reinforcement. A mixture of 25% by weight of shredded fiberglass (I / 82 (0.32 cm) in length), 8.9% by weight of carbon black concentrate (34% of carbon black in nylon 6, same concentrate as defined) in Example 2) and 66.1% by weight of nylon 6,6 was prepared using a rotating drum mixer. The nylon had a water content of 0.5-1.0% by weight. The mixture was combined using a single non-ventilated 24/1 L / D extruder of 1.52 (3.8 cm) diameter at a temperature of 285 ° C. The extruded material was extinguished in a pelletized water bath. A porous biostat designated T-4202 was prepared from the carbon black concentrate with 25% by weight of shredded glass fibers so that the reinforcement produced 25.5% by weight of carbon black in the final product. A mixture of 75% by weight of carbon black concentrate (34% by weight of carbon black in nylon 6, same concentrate as that described in example 2) and 25% by weight of shredded glass fiber (I / 82) (0.32) cm long) was prepared using a twin shell cone mixer. The concentrate had a water content of 0.5-1.0% by weight. The mixture was combined using a single non-ventilated 24/1 / LD extruder of 1.52 (3.8 cm) in diameter at a temperature of 285 ° C. The extruded material was extinguished in a water bath and pelletized.

EXAMPLE 4 This example shows a comparison between the biosport of porous nylon R533 of the invention and two commercial bioslides that are commonly used as supports for bacteria immobilized in bioreactors, ie, diatomaceous earth globules R635 from Manville Company and charcoal activated coconut charcoal Filtration Co. We conducted porosimetry analysis by intrusion of mercury in each sample. Brostate R533 had an average pore diameter of 83.5 μm, while the diatomite bitumen and activated coconut charcoal R635 had average pore diameters of 12.9 μm and 0.113 μm, respectively. The incremental intrusion (measured in μL of pore volume per gram of biostate) was plotted against the pore diameter for the three samples (figure 1). Figure 1 clearly shows the significant differences between the porous biosoporte R533 of the invention and the biosports R635 of diatomaceous earth and activated coconut charcoal. Brostate R533 contains a significantly greater number of pores with a pore diameter of more than 50 μm, indicating that the porous biosports of the invention would result in a faster onset after inoculation and a higher total yield for chemical biodegradation . In addition, the open porosity of the bioslides of the invention would result in a better penetration of the chemical and oxygen into the interior of the particle, resulting in higher total levels of microbial activity compared to conventional biosports having a limited diffusion of chemicals or oxygen.

EXAMPLE 5 This example demonstrates the effectiveness of porous nylon R533 pellets as a biostock for PNP1 of Pseudomonas sp. in the biodegradation of PNP in a packed bed bioreactor. A strain PNP1 of Pseudomonas sp. which had been isolated from a municipal sediment (see Heitkamp et al., "Biodegradation of p-Nitrophenol in aqueous Waste Stream by I mobilized Bacteria", Appl Environ. Microbiol., October 1990, pp. 2967-2973) was used as inoculum for the biosubjects in these experiments. This Pseudomonas sp. it is capable of completely degrading PNP as a sole source of carbon and energy. A waste stream of synthetic PNP (pH 7.8) consisting of medium strength inorganic mineral salts (L salts) containing PNP concentrations ranging from 100 to 1400 mg / L was pumped through the columns of immobilized bacteria to determine the performance of immobilized bacteria to degrade PNP. The reference PBRs in this study were Plexiglas columns that had an internal diameter of 8.9 cm. by 61 cm long by 0.5 cm wall. The columns used in the high-flow studies were Plexiglas tubes measuring 5.4 cm internal diameter by 61 cm long x 0.5 wall. The bottom of each column was sealed with a rubber stopper and a wire sieve located 63.5 mm above the base supported a bed depth of 305 mm of the biosount in each column. An air source was inserted through the rubber plug in the base to provide a continuous air supply to each column and air was introduced at a flow rate of 750 cc / in for the 8.9 cm column and 300 cc / min for the 5.4 cm column. This application of air maintained the oxygen saturation of the liquid along the length of each column during the length of the experiment. The waste stream of synthetic PNP was pumped into each column through a stainless steel tube located 2.54 cm above the bottom of the biostatic bed. The effluent that came from each column was discarded from an upper space for liquids by means of a drainage line placed 5.1 cm above the top of the biosport bed. The biosporte of porous nylon R533 was inoculated with a moderately cloudy culture of strain PNP1 of Pseudomonas sp cultivated in medium strength L salts containing 100 mg / L of PNP. The L salts were prepared according to Leadbetter, E.r. and foster, J.W. "Studies on some methane utilizing bacteria", Arch. Mikrobiiol, 30:91 118 (1958). The purity of this culture was verified by the selective placement on agar of L salts containing PNP, placement on a normal plaque counting agar (SPC) and by direct examination with light microscopy. The porous nylon biosporum was inoculated by recirculating pumping a one liter cloudy culture of Pseudomonas sp. PNP1 strain. at 1 ml / min through the PBR bed for 24 hours with continuous air application. Once the microbial degradation of PNP was observed in the PBR, synthetic wastes were pumped continuously through the PBR. Dosage liquid pumps from FMI Corporation (model RHSY, Oyster Bay, NY) were used to feed synthetic waste into the PBR at flow rates calibrated throughout the study. The chemical loading to the columns was increased by increasing the PNP concentration in the feed material to approximately 1400 mg / L and increasing the feed rate to 2 ml / min. In the second phase of the test, the PNP concentration was maintained at approximately 66 mg / L, but the flow rates were increased until the sensational advance of the PNP in the PBR effluent was observed. The biodegradation of PNP by PNP1 of Pseudomonas sp immobilized in porous nylon pellets of R533 in the PBR of 9.8 cm at increasing chemical loads is shown in figure 2. The chemical loading of PNP (mg / h) in the PBR was raised first the concentration of PNP in the synthetic medium from 400 mg / L to 1200 mg / L during the first 7 days of the experiment. Additional increases in PNP loading were achieved by stepwise increases in feed flow rate from 3 ml / min to 10 ml / min during days 15-25. Since significant levels of microbial biomass were observed on the porous nylon biostock during the second week of operation, the packed bed was fluidized by vigorous air injection on day 19. This fluidization caused the release of excess biomass in the PBR effluent and resulted in a very small observable excess biomass in the PBR after fluidization. Therefore, the packed bed was fluidized approximately every other day throughout the remainder of the experiment to avoid channeling of the liquid or loss of reactor volume due to accumulation of excess biomass in the PBR. The biodegradation of PNP by bacteria immobilized in the PBR showed a 15-25% breakthrough pattern of non-degraded PNP within 24 hours after each increase in chemical loading. Characteristically, the PBR would again gain a high rate of PNP biodegradation within the next 24-48 hours. Presumably, this recovery resulted from the additional growth of the bacteria in the biosoport in the PBR in response to each increase in chemical loading. However, the sensational breakthrough consisting of non-degraded PNP was observed in the PBR effluent after each day 33 when the PNP load was increased from 657 g / hr to 787 mg / hr. The removal of PNP fell initially to 86% and 91-96% of removal was recovered during the following 10 days (days 35-44) while the PNP load averaged 736 mg / hr. The yield of the PBR unexpectedly dropped to 74.77% removal on days 46-47. Since the chemical load had not increased in this time frame, the PBR did not contain excess biomass and no operational problems were evident, it was believed that the immobilized bacteria were strained by a lack of micronutrients or trace elements due to the long exposure to a synthetic food that contained only inorganic macronutrients and PNP. The addition of 5 mg / L of yeast extract, a common source of micronutrients and trace elements, restored performance. Throughout the rest of the experiment, the synthetic feed was supplemented with 5-10 mg / L of yeast extract to eliminate the limitation of micronutrients as an experimental variable. The PBR averaged 91% removal of PNP during the eleven-day period from days 52-62 when the PNP load averaged 707 mg / hr and 95.3% removal of PNP on days 74-96 (22 days) when the PNP load averaged 532 mg / hr. The production of immobilized bacteria on porous nylon R533 pellets was also evaluated for high flow applications. The concentration of PNP in the synthetic feed was lowered to approximately 40 mg / L and the flow was increased step by step throughout and through the PBR until the sensational advance of non-degraded PNP was observed in the effluent (figure 3). Nevertheless, flow rates as high as 40 ml / min did not result in any detectable discharge of non-degraded PNP. Since higher flow velocities were not practical in the laboratory due to the high volume of feed required, a portion of the porous nylon was transferred from the 8.9 cm internal diameter column to a column having an internal diameter of 5.4 cm. This significantly decreased the volume of the PBR, resulting in shorter hydraulic residence times for the same flows tested in the larger column. The smaller PBR maintained near-complete PNP removal at flow velocities of 10, 20, 25 and 30 mls / min, but fell to 51-69% removal at 40 ml / min on days 119-122 (FIG. 4). ). Table II shows a summary of the maximum chemical degradation rates for applications of high chemical concentration and high liquid flow of PNPl of Pseudomonas sp immobilized on a biosporte R533 porous nylon R533 in the PBR. In both cases, the PNPl of Pseudomonas sp immobilized on a porous nylon R533 biosoporte removed >90% of PNP.

TABLE II Maximum chemical degradation rates for PNPl of Pseudomonas sp immobilized in porous nylon biosporte R533 in the PBR Concentration Time Removal PNP Average of residence of PNP Removed Removed PNP »(mg / L) hydraulic (g / l / day) (g / l / day 40 12> 99 2.88 5.12 1200 130 90+ 5.92 10.5 * p-Nitrofinol in synthetic L-salts medium A sample of the biofilm from the biostatic bed in the PBR at the conclusion of the chemical loading study was placed on petri dishes containing SPC medium and 2% agar. The bacterial isolates were selected from the SPC plates based on differences observed in pigmentation, colony morphology, cell morphology and gram reaction. The isolates were transferred to agar plates containing 100 mg / L of PNP. The isolates capable of degrading PNP were determined by observing the clarification of the yellow PNP surrounding the colony. The isolated bacteria were incubated for 24 hours on Trypticasc Soy Agar before identification using a VITEK AMS microbial identification system (McDonnell Douglas Inc., St. Louis, MO). Cell morphology and gram staining were determined with an Axioskop light microscope (Zeiss, Germany). A major bacterial morphotype was isolated from the porous nylon biosport R533 at the conclusion of these experiments. This microorganism was identified as a Pseudomonas sp by the microbial identification system VITEK AMS and supposedly was the PNPl of Pseudomonas sp originally inoculated on the porous nylon biosporum.

EXAMPLE 6 The biosporte porous nylon R533 produced according to the method of the invention was analyzed to verify the presence of macropores using scanning electron microscopy. The micrographs of the porous nylon biosporte R533 were taken in three views: longitudinal surface (figure 5), longitudinal cross section (figure 6) and extreme view (figure 7). The longitudinal surface view at 15x magnification (FIG. 5A) shows the rough fibrous characteristics of the extruded porous nylon biosport surface. The surface structure looks rough and irregular in texture and numerous large openings provide microbial penetration, fixation and growth. The longitudinal surface at a magnification of 70x (Figure 5B) more clearly shows the large openings in the surface of the fibrous polymer biostock. It should be mentioned that it has been observed that some large openings that vary in size from 20-700μm extend from the longitudinal surface downwards into the porous biosporous, thus providing easy internal access to the inoculated bacteria. The longitudinal cross sectional view at a 15x magnification (Figure 6A) shows that extremely large pore openings exist along the interior of the biosoport running parallel to the extrusion direction. It should be mentioned that many of these cavities are 800-1200μM in length and some are as long as 3.9mm. These cavities allow the existence of large populations of bacteria of chemical degradation within the biosport. Moreover, the matrix of the open structure of the biosporum eliminates growth limitations due to the low diffusion of nutrients or chemical in the biosupport. The longitudinal cross-sectional view at 50x magnification (Figure 6B) shows more clearly the size and shape of these large internal cavities. The diameters of these long cavities vary from 30-690 μM and most have a diameter of 95-295 μM. The extreme view at a magnification of 70x (figure 7) shows that the long cavities that run through the porous biosporum (as seen in figure 6A and 6B) exist as open channels and are accessed through openings in the cut end of the biosoporte. These openings are numerous through the end of the biostock and have diameters ranging from 40-415 μM providing easy access to the inoculated bacteria. It is clear from these scanning electron microscopy analyzes that the porous nylon biosum contains a large number of very large pore openings. Moreover, this pore openings occur along the interior of the biosport and are accessible to microorganisms by the openings through both the sides and the cut ends of the biosport.

Claims (58)

NOVELTY OF THE INVENTION CLAIMS

1. - A composition for the biotratant of an aqueous waste stream comprising colonized microorganisms within the pores of a porous biosupport, said biosupport comprising: (a) 40-100% by weight of a polymeric material comprising a polymer selected from the group consisting of nylon, thermoplastic polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polysulfone, polyolefin, polyvinyl chloride, polycarbonate, polyimide, polyetheretherketone, polyphenylene sulfide, cellulose ester plastics, polyvinyl butyral, styrenic polymers, rigid thermoplastic polyurethanes, and mixtures thereof; (b) 0-60% by weight of a fiber reinforcement; (c) 0-60% by weight of an adsorbent material; and (d) 0-40% by weight of an inorganic filler, further characterized in that the sum of the amounts of fiber reinforcement, adsorbent material and inorganic filler in said biostock is 0-60% by weight and further characterized because said biosupport it has a specific gravity greater than the specific gravity of the water and pores of sufficient diameter for the microorganisms to form colonies within the pores.

2. The composition according to claim 1, further characterized in that the pores of said biosport have a diameter in the scale of 1 μm to 700 μm.

3. The composition according to claim 2, further characterized in that said pores have a diameter on the scale of 1 μm to 390 μm and an average diameter (based on volume) of at least 40 μm.

4. The composition according to claim 3, further characterized in that said pores have a volume of at least 0.2 mL / g for pore sizes in the range of 1 μm to 390 μm.

5. The composition according to claim 1, comprising 5 to 50% by weight of a fiber reinforcement.

6. The composition according to claim 5, comprising 15 to 40% by weight of a fiber reinforcement.

7. The composition according to claim 5, comprising 2 to 50% by weight of an adsorbent material.

8. The composition according to claim 1, comprising 40 to 80% by weight of said polymeric material.

9. The composition according to claim 5, comprising 5 to 30% by weight of an inorganic filler.

10. - The composition according to claim 1, further characterized in that said polymeric material comprises nylon and a material selected from the group consisting of polyolefin, styrene-butadiene rubber, an inorganic filler and mixtures thereof.

11. The composition according to claim 1, further characterized in that said nylon is selected from the group consisting of nylon 6, nylon 6,6, nylon 4.6, nylon 11, nylon 12, nylon 6.9, nylon 6.10 and mixtures or copolymers thereof.

12. The composition according to claim 9, further characterized in that said polymeric material contains 35 to 95% by weight of nylon.

13. The composition according to claim 1, further characterized in that said fiber reinforcement is composed of fibers selected from the group consisting of glass, carbon, aramid, fiber-forming inorganic material selected from alumina, silica, wollastonite, boron, boron nitride, boron carbide, silicon carbide or alumino-silicate and mixtures thereof.

14. The composition according to claim 13, further characterized in that said fiber reinforcement are shredded fibers.

15. The composition according to claim 13, further characterized in that said fiber reinforcement is fiberglass or carbon fiber.

16. - The composition according to claim 1, further characterized in that said adsorbent material is selected from the group consisting of carbon, ion exchange resins, zeolites and mixtures thereof.

17. The composition according to claim 16, further characterized in that said adsorbent material is carbon or activated carbon.

18. A process for biodegrading an aqueous waste stream containing organic contaminants comprising inoculating a bed of particles from a biosupport with an inoculum of a culture of microorganisms capable of biodegrading said organic contaminants, and making contact between said aqueous waste stream containing organic contaminants and microorganisms on said biosporum for a time sufficient to degrade said organic contaminants, further characterized in that said biostance comprises: (a) 40-100% by weight of a polymeric material comprising a polymer selected from the group consisting of nylon, thermoplastic polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polysulfone, polyolefin, polyvinyl chloride, polycarbonate, polyimide, polyetheretherketone, polyphenylene sulfide, cellulose ester plastics, polyvinyl butyral, polymers styrenics, polyurethanes r tected thermoplastics and mixtures thereof; (b) 0-60% by weight of a fiber reinforcement; (c) 0-60% by weight of an adsorbent material; and (d) 0-40% by weight of an inorganic filler, wherein the sum of the amounts of fiber reinforcement, adsorbent material and inorganic filler in said biostock is 0-60% by weight and wherein said biosport has a specific gravity greater than the specific gravity of the water and pores of sufficient diameter for the microorganisms to form colonies within the pores.

19. The process according to claim 18, further characterized in that said biosport has pores having a diameter in the scale of 1 μm to 700 μm.

20. The process according to claim 19, further characterized in that said pores have a diameter on the scale of 1 μm to 390 μm and an average diameter (based on volume) of at least 40 μm.

21. The process according to claim 20, further characterized in that said biosport has pores having a pore volume of at least 0.2 mL / g for pore sizes in the range of 1 μm to 390 μm.

22. The process according to claim 18, further characterized in that said biosport comprises 5 to 50% by weight of a fiber reinforcement.

23. The process according to claim 22, further characterized in that said biosport comprises 2 to 50% by weight of an adsorbent material.

24. - The process according to claim 22, comprising 5 to 30% by weight of an inorganic filler.

25. The process according to claim 18, further characterized in that said polymeric material in said biosport comprises nylon and a material selected from the group consisting of polyolefin, styrene-butadiene rubber, an inorganic filler and mixtures thereof.

26. The method according to claim 25, further characterized in that said polymeric material contains 35 to 95% by weight of nylon.

27. The method according to claim 18, further characterized in that said nylon in said biosport is selected from the group consisting of nylon 6, nylon 6,6, nylon 4,6, nylon 11, nylon 12, nylon 6,9 , nylon 6.10 and mixtures or copolymers thereof.

28.- A process for the treatment of an aqueous waste stream containing organic contaminants which comprises passing said aqueous waste stream through a packed bed reactor, the packed bed reactor contains a packed bed of biosupport particles that support microorganisms capable of biodegrading said organic contaminants, by means of a process in which the aqueous waste stream is oxygenated by introducing oxygen into the feed end of the packed-bed reactor, so as to subject said organic contaminants in the aqueous stream of oxygenated waste to the aerobic biodegradation and to produce a purified aqueous effluent, further characterized in that said biosupport comprises: (a) 40-100% by weight of a polymeric material comprising a polymer selected from the group consisting of nylon, thermoplastic polyester, ethylene-acetate copolymer vinyl, ethylene-alcohol copolymer v inyl, polysulfone, polyolefin, polyvinyl chloride, polycarbonate, polyimide, polyetheretherketone, polyphenylene sulfide, cellulose ester plastics, polyvinyl butyral, styrenic polymers, rigid thermoplastic polyurethanes and mixtures thereof; (b) 0-60% by weight of a fiber reinforcement; (c) 0-60% by weight of an adsorbent material; and (d) 0-40% by weight of an inorganic filler, wherein the sum of the amounts of fiber reinforcement, adsorbent material and inorganic filler in said biostock is 0-60% by weight and wherein said biosport has a specific gravity greater than the specific gravity of the water and pores of sufficient diameter for the microorganisms to form colonies within the pores.

29. The method according to claim 28, further characterized in that said biosport has pores having a diameter in the range of 1 μm to 700 μm.

30. The method according to claim 29, further characterized in that said pores have a diameter on the scale of 1 μm to 390 μm and an average diameter (based on volume) of at least 40 μm.

31. The process according to claim 29, further characterized in that said biosport has pores having a pore volume of at least 0.2 mL / g for pore sizes in the range of 1 μm to 390 μm.

32.- The method according to claim 28, further characterized in that said biosport comprises approximately 5 to 50% by weight of a fiber reinforcement.

33. The process according to claim 32, further characterized in that said biosport comprises 2 to 50% by weight of an adsorbent material.

34. The process according to claim 32, comprising 5 to 30% by weight of an inorganic filler.

35.- The method according to claim 28, further characterized in that said polymeric material in said biosport comprises nylon and a material selected from the group consisting of polyolefin, styrene-butadiene rubber, an inorganic filler and mixtures thereof.

36.- The procedure according to claim 35, further characterized in that said polymeric material contains 35 to 95% by weight of nylon.

37.- The method according to claim 28, further characterized in that said nylon in said biostock is selected from the group consisting of nylon 6, nylon 6,6, nylon 4,6, nylon 11, nylon 12, nylon 6,9 , nylon 6.10 and mixtures or copolymers thereof.

38.- A process for the treatment of an aqueous waste stream containing organic contaminants, comprising passing said waste aqueous stream through a fluidized bed reactor, said fluidized bed reactor including a recirculation line and containing a bed fluidization of biostatic particles that support microorganisms capable of biodegrading said organic contaminants, by a process in which the material fed to said fluidized bed reactor is oxygenated to thereby subject said organic contaminants in the oxygenated feed to aerobic biodegradation and to producing a purified aqueous effluent, wherein said material fed to said fluidized bed reactor comprises a recirculating stream of a portion of said effluent and said aqueous waste stream and said fed material is oxygenated by dissolving oxygen in said recirculation stream, said run aqueous waste body or said material fed to the fluidized bed reactor at a point external to the fluidized bed, wherein said biosensing comprises: (a) 40-100% by weight of a polymeric material comprising a polymer selected from the group consisting of nylon, thermoplastic polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polysulfone, polyolefin, polyvinyl chloride, polycarbonate, polyimide, polyetheretherketone, polyphenylene sulfide, cellulose ester plastics, polyvinyl butyral, styrenic polymers, thermoplastic rigid polyurethanes and mixtures thereof; (b) 0-60% by weight of a fiber reinforcement; (c) 0-60% by weight of an adsorbent material; and (d) 0-40% by weight of an inorganic filler, wherein the sum of the amounts of fiber reinforcement, adsorbent material and inorganic filler in said biosupport is 0-60% by weight, and wherein said bio-carrier has a specific gravity greater than the specific gravity of the water and pores of sufficient diameter for the microorganisms to form colonies within the pores.

39.- The method according to claim 38, further characterized in that said biosport has pores having a diameter in the range of 1 μm to 700 μm.

40.- The method according to claim 39, further characterized in that said pores have a diameter on the scale of 1 μm to 390 μm and an average diameter (based on volume) of at least 40 μm.

41.- The method according to claim 40, further characterized in that said biosport has pores having a pore volume of at least 0.2 mL / g for pore sizes in the range of 1 μm to 390 μm.

42.- The method according to claim 38, further characterized in that said biosport comprises 5 to 50% by weight of a fiber reinforcement.

43.- The process according to claim 42, further characterized in that said biosport comprises 2 to 50% by weight of an adsorbent material.

44. The process according to claim 42, comprising 5 to 30% by weight of an inorganic filler.

45. The method according to claim 38, further characterized in that said polymeric material in said biosport comprises nylon and a material selected from the group consisting of polyolefin, styrene-butadiene rubber, an inorganic filler and mixtures thereof.

46.- The method according to claim 45, further characterized in that said polymeric material contains 35 to 95% by weight of nylon.

47.- The method according to claim 38, further characterized in that said nylon in said biosport is selected from the group consisting of nylon 6, nylon 6,6, nylon 4,6, nylon 11, nylon 12, nylon 6,9, nylon 6.10 and mixtures or copolymers thereof.

48. The method according to claim 38, further characterized in that said organic contaminants are organic nitrogen compounds and said effluent contains water, ammonia and carbon dioxide.

49. - A process for preparing a porous biosupport comprising extruding in a non-vented extruder a composition comprising: (a) 40-100% by weight of a polymeric material comprising a polymer selected from the group consisting of nylon, thermoplastic polyester, copolymer ethylene-vinyl acetate, ethylene-vinyl alcohol copolymer, polysulfone, polyolefin, polyvinyl chloride, polycarbonate, polyimide, polyetheretherketone, polyphenylene sulfide, cellulose ester plastics, polyvinyl butyral, styrenic polymers, rigid thermoplastic polyurethanes and mixtures of the same; (b) 0-60% by weight of a fiber reinforcement; (c) 0-60% by weight of an adsorbent material; and (d) 0-40% by weight of an inorganic filler, wherein the sum of the amounts of fiber reinforcement, adsorbent material and inorganic filler in said biosupport is 0-60% by weight, in the presence of 0.1 to 7. % by weight of water, a foaming agent or mixtures thereof, and pelletizing the extruded material from said extruder, wherein said bio-bearing has a specific gravity greater than the specific gravity of the water and pores of sufficient diameter for the microorganisms form colonies within the pores.

50.- The process according to claim 49, further characterized in that the amount of water, foam forming agent or mixture thereof is 0.1 to 5% by weight.

51.- The method according to claim 61, further characterized in that said biosport has pores having a diameter in the range of 1 μm to 700 μm.

52. The method according to claim 51, further characterized in that said pores have a diameter on the scale of 1 μm to 390 μm and an average diameter (based on volume) of at least 40 μm.

53. The method according to claim 52, further characterized in that said biosupport has pores having a pore volume of at least 0.2 mL / g for pore sizes in the range of 1 μm to 390 μm.

54.- The method according to claim 49, further characterized in that said biosport comprises 5 to 50% by weight of a fiber reinforcement.

55.- The process according to claim 54, further characterized in that said biosport comprises 2 to 50% by weight of an adsorbent material.

56.- The process according to claim 54, comprising 5 to 30% by weight of an inorganic filler.

57.- The method according to claim 49, further characterized in that said polymeric material in said biosport comprises nylon and a material selected from the group consisting of polyolefin, styrene-butadiene rubber, an inorganic filler and mixtures thereof.

58. - The method according to claim 57, further characterized in that said polymeric material contains 35 to 95% by weight of nylon. 59.- The method according to claim 49, further characterized in that said nylon in said biosport is selected from the group consisting of nylon 6, nylon 6,6, nylon 4,6, nylon 11, nylon 12, nylon 6,9, nylon 6.10 and mixtures or copolymers thereof. The method according to claim 49, further characterized in that said foaming agent is fluorinated aliphatic hydrocarbons, 1,1-azobisformamide, p, p'-oxybis- (benzenesulfonyl hydrazide), p-toluenesulfonyl semicarbazide, trihydrazintriazine , 5-phenyltetrazole, sodium bicarbonate and mixtures thereof. 61.- The method according to claim 49, further characterized in that said composition is extruded in the presence of water. 62.- The procedure according to claim 49, further characterized in that said composition further comprises an amount of a polymeric additive material, wherein said additive material contains one or more of said fiber reinforcement, adsorbent material, inorganic fillers and polymeric material in addition to a plastic or rubber material not suitable as the polymeric material (a) of said composition, and wherein the amount of said plastic or rubber material plus the amount of any additive other than said fiber reinforcement, adsorbent material and inorganic filler present in said composition is up to 25 %. 63. The biosport according to claim 1, further characterized in that said biosport further comprises an amount of a polymeric additive material, wherein said additive material contains one or more of said fiber reinforcement, adsorbent material, inorganic fillers and polymeric material , in addition to an unsuitable plastic or rubber material such as the polymeric material (a) of said biosport, and wherein the amount of said plastic or rubber material plus the amount of any additive other than said fiber reinforcement, Adsorbent material and inorganic filler present in said composition is up to 25%. 64.- The method according to claim 18, further characterized in that said biosport further comprises an amount of a polymeric additive material, wherein said additive material contains one or more of said fiber reinforcement, adsorbent material, inorganic fillers and polymeric material , in addition to an unsuitable plastic or rubber material such as the polymeric material (a) of said biosport, and wherein the amount of said plastic or rubber material plus the amount of any additive other than said fiber reinforcement, Adsorbent material and inorganic filler present in said composition is up to 25%. The method according to claim 28, further characterized in that said composition further comprises an amount of a polymeric additive material wherein said additive material contains one or more of said fiber reinforcements, adsorbent material, inorganic fillers and polymeric material in addition of an unsuitable plastic or rubber material as the polymeric material (a) of said composition and wherein the amount of said rubber plastic material plus the amount of any additive other than said fiber reinforcement, adsorbent material and inorganic filler present in said composition is 25%. 66. - The method according to claim 47, further characterized in that said composition further comprises an amount of a polymeric additive material wherein said additive material contains one or more of said fiber reinforcements, adsorbent material, inorganic fillers and polymeric material in addition to an unsuitable plastic or rubber material as the polymeric material (a) of said composition and wherein the amount of said rubber plastic material plus the amount of any additive other than said fiber reinforcement, adsorbent material and filler inorganic present in said composition is 25%. 67.- The method according to claim 49, further characterized in that the amount of water, foaming agent or mixture thereof is

0. 1 to 2% by weight. 68.- The method according to claim 49, further characterized in that the amount of water, foaming agent or mixture thereof is 0.2 to 1% by weight.