Abstract: Embeddable extensions of the functionality of email and calendaring applications are described herein. An originating email and calendaring application formats meeting items to include extensible content, e.g., within the body field of the meeting item. Recipient email and calendaring applications receive the meeting items and, depending on whether they are configured to provide an extended functionality, will either deploy the extensible content item according to the extended functionality or present the extensible content item according to a standardized functionality. The body field includes the extensible content item according to the standardized functionality that is interpretable by configured clients to provide the extended functionality.

Abstract: The invention relates to a bioreactor including: a light source (200); a light sensor (300) facing said light source; a vat (100) that is placed between the light source (200) and the light sensor (300), said vat being intended to receive a culture medium comprising a cellular culture of photosynthetic microorganisms; a controller (400) connected to the light sensor (300) in order to control the vat (100) to obtain a chosen cellular-culture concentration (xi) in the culture medium during a working period, said light source (200) being capable of emitting incident light (L) of an input light intensity (Iin) in the direction of the vat (100), and the light sensor (300) being capable of measuring an output light intensity (Iout) and of transmitting data relating to this intensity (Iout) to the controller for the control of the vat; and a system (500) for controlling the light source (200), this system being arranged to adjust, during a period shorter than or equal to said working period, the input light intensit

Abstract: The present invention provides a process of cultivating microalgae and a joint method of same jointed with denitration. During the microalgae cultivation, EM bacteria is added into the microalgae suspension. In the nutrient stream for cultivating microalgae, at least one of the nitrogen source, phosphorus source and carbon source is provided in the form of a nutrient salt. During the cultivation, the pH of the microalgae suspension is adjusted with nitric acid and/or nitrous acid. The joint method includes (1) a step of cultivating microalgae; (2) a separation step of separating a microalgae suspension obtained from step (1) into a wet microalgae (microalgae biomass) and a residual cultivation solution; and (3) a NOx absorbing/immobilizing step of denitrating an industrial waste gas with the residual cultivation solution obtained from step (2). The nutrient stream absorbed with NOx obtained from step (3) is used to provide nitrogen source to the microalgae cultivation of step (1).

Abstract: Disclosed is a mass-cultivation system for microalgae, including a reactor that contains a cultivation liquid in the interior thereof, wherein the liquid includes functional particles. According to the mass-cultivation system for microalgae according to the present invention, because various functions that are necessary for cultivation of microalgae may be uniformly distributed in a cultivation liquid by allowing functional particles having various functions to flow in the cultivation liquid, a suitable environment may be created based on the cultivation of a large amount of microalgae and the growth of microalgae so that a high efficiency cultivation system may be realized while the problems of mass-cultivation of an existing cultivation system may be solved.

Abstract: A dielectric substrate made from sunflower seed shells has good moldabiltiy and low water adsorption for use in creating antenna or other devices. The dielectric substrate is made by pyrolizing sunflower seed shells or husks and collecting the resulting tar to create the substrate.

Abstract: There is provided a process for growing a phototrophic biomass in a reaction zone. The process includes treating an operative carbon dioxide supply-comprising gaseous material feed so as to effect production of a carbon dioxide-rich product material. The carbon dioxide concentration of the carbon dioxide-rich product material is greater than the carbon dioxide concentration of the operative carbon dioxide supply-comprising gaseous material feed. Production of at least a fraction of the operative carbon dioxide supply-comprising gaseous material feed is effected by a gaseous exhaust material producing process. At least a fraction of the carbon dioxide-rich product material is supplied to the reaction zone so as to effect growth of the phototrophic biomass by photosynthesis in the reaction zone.

Abstract: Methods of producing a treated gas by removing nitrogenous compounds are disclosed. Methods of recovering nitrogenous compounds from a gas stream are disclosed. Methods of producing a fertilizer product from organic waste are disclosed. The methods may include introducing a gas stream having nitrogenous compounds into a nitrogenous liquid containing a salt of ammonia to absorb the nitrogenous compounds in the liquid and produce a treated gas. The methods may also include controlling the pH of certain solutions or introducing an oxidant into certain solutions to produce nitrogen ions. Systems for removing nitrogenous compounds including a reaction subsystem, an oxidation control subsystem, a dissolved solids concentrator, and a recirculation line are also disclosed. The systems may be employed to remove nitrogenous compounds from a gas stream, recover the nitrogenous compounds from the gas stream, or produce a fertilizer product from the recovered nitrogenous compounds.

Abstract: A system for removing undesirable compounds from contaminated air includes a biofilter having porous glass media. Hydrogen sulfide is removed from contaminated air by passing the contaminated air through the biofilter.

Abstract: A method is presented for biological removal of contaminants like sulfide from ground waters and industrial waters. A fixed film compartmentalized bioreactor or bioreactors are used to convert sulfide to elemental sulfur and the subsequent conversion of the elemental sulfur to sulfates. The present invention uses a packed bed bioreactor configuration that uses packing material to maximize the concentration of sulfide oxidizing bacteria.

Abstract: Methods and systems for producing short carbon chain weak organic acids (e.g., acetic acid) from a gas stream rich in carbon dioxide. The systems include a liquid-gas contact unit a flue gas desulfurization unit), and a bacterial strain disposed in the liquid-gas contact unit. The bacterial strain reduces a concentration of carbon dioxide in the gas stream, and produces one or more organic acids (e.g., acetic acid, butyric acid, propionic acid, lactic acid, or combinations thereof). Related methods include providing a gas stream rich in carbon dioxide, introducing the gas stream into a liquid-gas contact unit, preparing an inoculum comprising a bacterial strain adapted to produce organic acid(s) from the carbon in the gas stream, and inoculating the liquid-gas contact unit with first amount of the inoculum such that the bacteria therein consume carbon dioxide from the gas stream, producing the organic acid(s).

Abstract: A system for producing an ion concentration gradient and a temperature-responsive electrolyte material which are utilizable, for example, for efficiently converting heat energy that has been discarded into reusable energy or for efficiently recovering an acid gas, such as carbon dioxide is provided. A temperature-responsive electrolyte is used to produce an ion concentration gradient by means of a temperature gradient. The temperature-responsive electrolyte is used in the state of an aqueous solution and also in the state of a solid phase.

Abstract: Described here is a method for increasing the transfer of a gas substrate in microbial fermentation, comprising incubating an emulsion comprising an oil phase and an aqueous phase droplet dispersed in the oil phase, and supplying the gas substrate to the oil phase, wherein the aqueous phase droplet comprises a microorganism, and wherein the emulsion is stabilized by a surfactant or an amphiphilic particle that is adsorbed to an interface of the oil phase and the aqueous phase. Also described is an emulsion for microbial fermentation, comprises an oil phase and an aqueous phase droplet dispersed in the oil phase, wherein the aqueous phase droplet comprises a microorganism, wherein the emulsion comprises a gas substrate externally-supplied to the oil phase, and wherein the emulsion is stabilized by a surfactant or an amphiphilic particle that is adsorbed to an interface of the oil phase and the aqueous phase.

Abstract: A formulation and process for capturing CO2 use an absorption mixture containing water, biocatalysts and a carbonate compound. The process includes contacting a CO2-containing gas with the absorption mixture to enable dissolution and transformation of CO2 into bicarbonate and hydrogen ions, thereby producing a CO2-depleted gas and an ion-rich solution, followed by subjecting the ion-rich solution to desorption. The biocatalyst improves absorption of the mixture comprising carbonate compounds and the carbonate compound promotes release of the bicarbonate ions from the ion-rich solution during desorption, producing a CO2 gas stream and an ion-depleted solution.

Abstract: A device for continuous dry methanation in a fermenter having a closed tank having at least one compartment to ferment the slurry comprising at least 17% dry matter. An injector to inject pressurized gas close to the bottom of the compartment via at least one chimney that descends through the compartment. The injected gas rising through the slurry creates a convective movement in the slurry around the chimney to stir the matter at the bottom of the compartment. The tank can include a first compartment into which the slurry is introduced and a second compartment into which the hydrolyzed slurry flows after hydrolysis and acidogenesis in the first compartment. Methanogenesis takes place in the second compartment.

Abstract: Biogas containing H2S and CO2 is upgraded by removing H2S using PTSA and CO2 using two stages of gas separation membranes. The first stage permeate may optionally be used a regeneration gas stream. The second stage permeate may optionally be used a cool down gas stream. The PTSA unit includes two or more adsorbent beds each selective for water, VOCs, and H2S over CO2 and for H2S over methane.

Abstract: A system for removing undesirable compounds from contaminated air includes a biofilter having porous glass media. Hydrogen sulfide is removed from contaminated air by passing the contaminated air through the biofilter.

Abstract: The present invention relates to a novel membrane module for separating a fluid feed stream into a permeate stream and a retentate stream. The membrane module according to the invention is characterized in that all components are housed in a 20?, 40?, 45? HC, 45? PW or 53? HC container, whereby the membrane module can be transported and handled in a very simple and cost-effective manner despite its comparatively large volume and its high weight. The membrane module is furthermore characterized by its large membrane surface area compared with usually used membrane modules, whereby the number of individual membrane modules required in practical use can be reduced many times over. The present invention furthermore relates to a process for separating a fluid feed stream into a permeate stream and a retentate stream using the membrane module according to the invention.

Abstract: An electrolytic system for treating wastewater by electrocoagulation, electroflotation or a combination of both is disclosed. The electrolytic system comprises a first electrolytic reactor adapted for receiving the wastewater to be treated, the first electrolytic reactor comprising at least one cathode and at least one anode to perform a first electrolytic treatment for eliminating organic matter and calcium present in the wastewater that impact on nucleation of struvite; and a second electrolytic reactor downwardly connected to the first electrolytic reactor, the second electrolytic reactor comprising at least one cathode and at least one magnesium anode to perform a second electrolytic treatment for producing Mg2+ ions which react with NH4+ and orthophosphates from said wastewater to form a struvite precipitate. The electrolytic system allows eliminating simultaneously orthophosphate and ammonium from the wastewater while enabling the production of struvite.

Abstract: A method for recovering carbon dioxide from gas, which method includes the steps of: pressurizing gas, feeding pressurized gas and water used as a solvent to an absorption column to 3 to 10 bar absolute pressure, feeding water received from the absorption column and carbon dioxide absorbed therein to a desorption column for recovering carbon dioxide from the water, recirculating water exiting the desorption column to the absorption column, recovering carbon dioxide exiting the desorption column, feeding at least part of the gas to an auxiliary desorption column prior to pressurizing the gas, and sending water exiting the desorption column back to the auxiliary desorption column. The method also applies to a corresponding system.

Abstract: Multi-stage, biological processes and systems for converting a C1 carbon source to desired end products are described. The processes comprise dividing a gaseous C1-containing substrate, in parallel, among multiple bioreactor stages. Liquid products are successively fed, in series, from a first bioreactor stage to downstream bioreactor stages. Operation can be simplified by avoiding the requirement for microorganism separation and recycle at each stage. In addition, overall vapor-liquid mass transfer for the combined stages is very favorable, leading to high end product productivity with comparably low byproduct metabolite productivity.

Abstract: A photobioreactor has an optical waveguide formed at least in part from a highly scattering optically transmitting polymer. The optical waveguide has a light distributing part immersed in a container holding photoactive biological material and a light collecting part outside the container.

Abstract: A multi-stage process for recovering acid gas from natural gas having high acid gas contents utilizes two or more membrane absorption contactors arranged in series. The first membrane absorption contactor uses a physical solvent to remove a high volume of acid gas transferred across a membrane, and to reduce the acid gas content in the natural gas to a lower level that can be managed using chemical solvents. The second and, if needed, subsequent membrane absorption contactors can use a chemical solvent to remove acid gas transferred across the respective membranes and reduce the acid gas content in the natural gas to very low levels, if needed, depending on product specifications.

Abstract: Method for preparing zinc-histidine self-assembly biomimetic complex activating reaction to convert carbon dioxide into bicarbonate ion, zinc-histidine self-assembly biomimetic complex by preparation method, and method for reducing carbon dioxide using zinc-histidine self-assembly biomimetic complex.

Abstract: Biomass production apparatus is disclosed and comprises a stack of trays, each tray, in use, being in receipt of a respective layer of liquid, the layers being spaced apart from one another such that each layer has associated therewith a respective headspace. Light sources are provided for each layer and are disposed in the headspace associated with said each layer, to illuminate, at least in part, said each layer.

Abstract: A system for capturing and storing carbon dioxide. The CO2 sequestration system may include one or more sub-systems for generating electricity, a heat exchange system which may regulate temperature, and a conversion tank. The conversion tank may contain water with dissolved compounds and a catalyst. Carbon dioxide may be converted into carbonate minerals and drawn off to be used in any of a variety of applications.

Abstract: Fluids viscosified with viscoelastic surfactants (VESs) may have their viscosities reduced (gels broken) by the direct or indirect action of an internal breaker composition that contains at least one mineral oil, at least one polyalphaolefin oil, at least one saturated fatty acid and/or at least one unsaturated fatty acid. The internal breaker may initially be dispersed oil droplets in an internal, discontinuous phase of the fluid. In one non-limiting embodiment, the internal breaker, e.g. mineral oil, is added to the fluid after it has been substantially gelled. An oil-soluble surfactant is present to enhance or accelerate the reduction of viscosity of the gelled aqueous fluid.

Abstract: A biofilter (1) having filter media (7) in a stowage space (5) having sidewalls and a bottom, inlet opening (15) for the unpurified gases/air and the stowage space (5) is made of flexible gas-tight material filled at least partly with the filter media (7). A biofilter system having two or more biofilters (1) is also described.

Abstract: A biological odor control system includes a vessel and a nutrient tank mounted and attached to an outer surface of the vessel such that the nutrient tank does not extend into a housing of the vessel. The vessel can include a housing, a gas inlet, a gas outlet, a first media bed positioned within the housing of the vessel, and an irrigation system adapted to provide moisture, nutrients, and/or mixtures thereof to the first media bed within the housing of the vessel. A vessel and method for treating odorous gas are also disclosed.

Abstract: A method for the biological decomposition of organic compounds of the group of hydrocarbons, fats, oils, waxes, and derivatives thereof as well as mixtures thereof in media polluted therewith, in the presence of at least one dispersant, wherein the medium polluted with the pollutants is treated with at least one dispersant and with microorganisms.

Abstract: Provided is a defoamer for fermentation which has excellent dispersibility in water and forms neither a precipitate nor oil droplets when the dispersion is heated, and which is highly effective in defoaming fermentation media. This defoamer contains a reaction product obtained by mixing a fat or oil having an iodine value of 40 to 130 with glycerin or like in a molar ratio of from 3/2 to 1/2 to obtain a mixture, causing 4 to 17 mol of propylene oxide to add to 1 mol of the mixture, and then causing 20 to 40 mol of ethylene oxide and 70 to 110 mol of propylene oxide to block-wise add thereto in this order, the reaction product having an ethylene oxide/propylene oxide molar ratio of from 1/4 to 2/5.

Abstract: The present invention relates to air purification. The present invention provides a system for reducing carbon dioxide concentration in air in locations with sub-tropical to temperate climates and method of reducing carbon dioxide concentration using the system.

Abstract: The present invention generally relates to carbonic anhydrase xerogel particles comprising a polysilicate-polysilicone copolymer and carbonic anhydrase. The carbonic anhydrase xerogel particles can be used for carbon dioxide capture.

Abstract: There is provided a process of growing a phototrophic biomass in a reaction zone. Gaseous exhaust material is produced with a gaseous exhaust material producing process, wherein the gaseous exhaust material includes carbon dioxide. A discharge of the gaseous exhaust material is supplied to the reaction zone and is modulated. A bypass gaseous exhaust material, being supplied to another unit operation, is also modulated.

Abstract: The present invention generally relates to improvements in enzyme immobilization, particularly for use in the field of carbon dioxide capture and sequestering. It has been discovered that the utilization of sol-gel processes to immobilize enzymes in polysilicate-polysilicone copolymer coatings and particles, and the deposition of these coatings on solid state supports or use of suspensions of these particles, provides significant benefits for use in industrial applications involving enzymatic catalysts.

Abstract: A zero-discharge landfill process is disclosed herein. The process described in the present invention recycles the exhaust gases from a combustion engine which reheats the landfill and provides moisture. Additionally, the CO2 from the exhaust gases releases additional methane. Methane production in landfills can thus be enhanced by the method of the present invention. Furthermore, a portion of the exhaust gas can be used to cultivate algae in a cultivation tank. The cultivation of the algal species is enhanced in the presence of water, CO2, CO, and the elevated temperatures. Optionally, a first portion of the cultivated algae can be passed through the landfill to increase methane production in the landfill and a second portion of the cultivated algae can be transferred to a biodiesel production tank, for the conversion of the one or more algal oils and lipids to a biodiesel or a biofuel by a transesterification reaction.

Abstract: Methods and systems for capturing and storing carbon dioxide are disclosed. In some embodiments, the methods include the following: mixing materials including magnesium or calcium with one or more acids and chelating agents to form a magnesium or calcium-rich solvent; using the organic acids derived from biogenic wastes as acids or chelating agents; generating carbonate ions by reacting a gas including carbon dioxide with a carbonic anhydrase biocatalyst; reacting the solvent with the carbonate ions to form magnesium or calcium carbonates; recycling a solution containing the biocatalyst after forming magnesium or calcium carbonates for re-use in the generating step; using the magnesium and calcium carbonates as carbon neutral filler materials and using the silica product as green filler materials or inexpensive absorbents.

Abstract: Biomass gasification systems including a biofilter assembly adapted to be disposed within a filter unit of a biomass gasification system are provided. The biofilter assemblies may be adapted to filter particulate matter from a producer gas flowing through the filter unit while allowing a remainder of the producer gas to pass through the biofilter assembly. The biofilter assembly may include a support structure and a biofilter disposed on the support structure and including a biomaterial adapted to be gasified in a biomass gasification reactor of the biomass gasification system.

Abstract: A bioreactor designed to produce N2O from organic nitrogen and/or reactive nitrogen in waste is coupled to a hardware reactor device in which the N2O is consumed in a gas phase chemical reaction, e.g., catalytic decomposition to form oxygen and nitrogen gas. Heat from the exothermic reaction may be used to generate power. The bioreactor may use communities of autotrophic microorganisms such as those capable of nitrifier denitrification, ammonia oxidizing bacteria, and/or ammonia oxidizing archaea. A portion of the N2O dissolved in aqueous effluent from the bioreactor may be separated to increase the amount of gas phase N2O product. The amount of the gas phase N2O in a gas stream may also be concentrated prior to undergoing the chemical reaction. The N2O may alternatively be used as an oxidant or co-oxidant in a combustion reaction, e.g., in the combustion of methane.

Abstract: A method to produce N2O from organic nitrogen and/or reactive nitrogen in waste uses a bioreactor coupled to a hardware reactor device in which the N2O is consumed in a gas phase chemical reaction, e.g., catalytic decomposition to form oxygen and nitrogen gas. Heat from the exothermic reaction may be used to generate power. The N2O may alternatively be used as an oxidant or co-oxidant in a combustion reaction, e.g., in the combustion of methane.

Abstract: A bioreactor designed to produce N2O from organic nitrogen and/or reactive nitrogen in waste is coupled to a hardware reactor device in which the N2O is consumed in a gas phase chemical reaction, e.g., catalytic decomposition to form oxygen and nitrogen gas. Heat from the exothermic reaction may be used to generate power. The N2O may alternatively be used as an oxidant or co-oxidant in a combustion reaction, e.g., in the combustion of methane. The bioreactor may have various designs including a two-stage bioreactor, a hollow-fiber membrane bioreactor, or a sequencing batch reactor. The bioreactor may involve Fe(II)-mediated reduction of nitrite to nitrous oxide.

Abstract: The present invention relates to a method for biologically treating carbon dioxide using the sulfur-oxidizing chemolithoautotroph Sulfurovum lithotrophicum 42BKT. The method of the present invention may enable carbon dioxide to be fixed or converted in high-concentration and high-pressure conditions which do not allow the biological photosynthetic conversion of microalgae or the like, and may exhibit high efficiency in the fixation of carbon dioxide as compared to existing methods for biologically treating carbon dioxide using microalgae. Further, the method of the present invention may use a gas mixture without a process of separating nitrogen and other gases, thus simplifying the process of the fixation or conversion of carbon diode.

Abstract: Implementations disclosed herein provide a scrubber system for the reduction and removal of acid gas from a gas stream. The scrubber system includes a dry chemical scrubber having an amount of bacteria therein. A gas stream containing an acid gas contaminant such as H2S is directed into and treated by the dry chemical scrubber; both media within the scrubber system and bacteria reduce the level of acid gas contaminant in the gas stream. In some implementations, the bacteria is carried over from a biological scrubber fluidly connected upstream of the dry chemical scrubber. The pH of the gas stream from the biological scrubber may be regulated prior to passing into the dry chemical scrubber.

Abstract: Disclosed is a method for removing carbon dioxide from a gas stream, comprising placing the gas stream in contact with a resin, wetting the resin with water, collecting water vapor and carbon dioxide from the resin, and separating the carbon dioxide from the water vapor. The resin may be placed in a chamber or a plurality of chambers connected in series wherein the first chamber contains resin that was first contacted by the gas, and each successive chamber contains resin which has been wetted and carbon dioxide collected from for a greater period of time than the previous chamber, and so on, until the last chamber. Secondary sorbents may be employed to further separate the carbon dioxide from the water vapor.

Abstract: A process of removing SO2 from a flue gas with a trickling filter using modified ceramsite packing is described. The biological flue gas desulfurization process includes: feeding the flue gas containing sulfur dioxide through the column bottom into the biomembrane trickling filter at certain temperature, contacting with the modified ceramsite biomembrane packing and purifying, which purified flue gas is discharged via the column top; and spraying the nutrient fluid rich in high concentration of the desulfurization strain through the top to the modified ceramsite biomembrane packing, thereby the sulfur-bearing pollution source in the flue gas is degraded, so as to discharge a purified flue gas satisfying the environmental requirements.

Abstract: The present invention generally relates to improvements in enzyme immobilization, particularly for use in the field of carbon dioxide capture and sequestering. It has been discovered that the utilization of sol-gel processes to immobilize enzymes in polysilicate-polysilicone copolymer coatings and particles, and the deposition of these coatings on solid state supports or use of suspensions of these particles, provides significant benefits for use in industrial applications involving enzymatic catalysts.

Abstract: A method for removing carbon dioxide from methane-containing crude gases, especially biogas, by pressure scrubbing, using a physical solvent, includes circulating the contaminated scrubbing solution after regeneration. A plant suitable for carrying out the method considerably reduces the methane loss which arises through methane slippage and improves the overall energy balance of the method. Laden scrubbing solution obtained from the pressure scrubbing is treated at least in one flash stage before the first stripping stage. In addition, a nitrogen, oxygen, carbon dioxide and methane-containing gas mixture drawn off from the flash stage is cleaned in a scrubbing stage by purified scrubbing solution drawn off from the second stripping stage and supplied in countercurrent, forming a high-purity methane gas.

Abstract: Disclosed herein are modified carbonic anhydrase enzymes, and a process of using same for the extraction, production and purification of carbon dioxide gas. More particularly, modified carbonic anhydrase enzymes are used for the production, purification of carbon dioxide and the products of the hydration reaction, hydrogen and bicarbonate ions Also, this technology is used to enhance the production of carbon dioxide in blood or in reverse osmosis desalination to remove carbon dioxide. Specifically, the invention relates to a modified carbonic anhydrase enzyme possessing improved activity and a process whereby immobilized modified carbonic anhydrase contained within a reactor device catalyzes the reversible hydration of carbon dioxide.

Abstract: Biochemical decomposition of undesirable gaseous contaminants, including nitrogen oxides, VOC's, carbon monoxide and sulfur oxides, and malodorous contaminants, is achieved by passing a gas stream through a managed landfill providing microbiological activity capable of degrading the contaminants. Gases suitable for treatment include fuel combustor exhaust, landfill gases, putrescent gases and the like. The landfill functions as a biological reactor (bioreactor), where water is added if or as necessary to achieve concentrations between about 20% and about 65% by weight, and desired microbial contaminant abatement action. By a permeation of the polluted gas through the landfill, there is a consumption of polluting gases by microorganisms present in the landfill. The process enables increased combustion of fuels, such as landfill gases, whose energy values are currently wasted or are not available due to emissions problems.

Abstract: The invention relates to the field of reduction of CO2 emission, more in particular to CO2 capture and conversion. The invention further relates to the culturing of algae. One object of the present invention is to provide an alternative method for capturing and conversion of CO2 from a gaseous stream.

Abstract: A biogas desulfurization device comprises an anaerobic system, a desulfurization liquid circulating system, an oxygen supply device and a desulfurization system, wherein the anaerobic system is used for generating biogas and filling the generated biogas into the desulfurization system, the desulfurization liquid circulating system is used for filling the desulfurization liquid into the desulfurization system and recycling the desulfurization liquid that has undergone the desulfurization operation, the oxygen supply device is used for filling air into the desulfurization system, and the desulfurization system which comprises at least one stage desulfurization tower group is used for carrying out the desulfurization operation on the biogas from the anaerobic system, the desulfurization operation is conducted by the desulfurization liquid received from the desulfurization liquid circulating system in an aerobic environment.