Institute of Gas Technology

United Gas Pipe Line Company

Transagra Corporation

Sambhunath Ghosh

Donald L Klass

Paul B Tarman

David P Chynoweth

John R Conrad

Paul A Fedde

Michael P Henry

A two phase anaerobic digestion process for production of methane from organic carbonaceous material in which an active acid forming microbial population is maintained in a first acid forming digestion phase and an active methane forming microbial population is maintained in a second methane forming digestion phase, the liquid effluent from the acid forming digestion phase being passed to a first methane forming digester and gaseous product from the acid forming digestion phase being passed to a second separated methane forming digester for production of methane in the first and second methane forming digesters of the methane forming digestion phase. The two separated methane digestion phases provide increased overall methane production.

Two phase anaerobic digestion

A process for improved methane production by anaerobic digestion of aquatic plant material at least a portion or all of which has been grown in organically polluted water. Mixtures of aquatic plant material one portion of which has been grown in non-polluted and a second portion comprising over about 10 weight percent which has been grown in organically polluted water may be used to result in a synergistic yield of methane. The liquid effluent from the digester may be advantageously returned to the aquatic plant growing pond to maintain the desired organic pollution. The process provides for improved methane production from aquatic plant material which is, by itself, recalcitrant to anaerobic digestion.

Methane production from and beneficiation of anaerobic digestion of

A process for gas production and accelerated bioleaching of organic materials by acid forming bacteria in beds of organic solids, such as landfills, passing the leachate of hydrolysis and liquefaction products of microbial action of the microorganisms with the organic material to an acid phase digestion zone to regenerate an activated culture of acid forming microorganisms for recirculation to the bioleaching zone. The supernatant from the acid phase digestion zone may be passed to a methane phase digestion zone operated under conditions to produce methane rich gas. The supernatant from the methane phase digestion zone containing nutrients for the acid forming microorganisms and added sewage sludge or other desired nutrient materials may be circulated to the acid phase digestion zone or to the bioleaching zone. Low Btu gas is withdrawn from the acid phase digestion zone while high Btu gas is withdrawn from the methane phase digestion zone and may be upgraded for use in SNG. The process of this invention is applicable to small as well as large beds of organic solids, such as waste landfills, provides simultaneous disposal of municipal solid waste and sewage sludge or other aqueous organic waste in a landfill which may be stabilized much more quickly than an uncontrolled landfill as presently utilized.

Gas production by accelerated bioleaching of organic materials

A process for improved methane production resulting in higher yield and higher production rates by anaerobic digestion of a mixture of plant material and organic waste. The process is suitable for production of synthetic natural gas and through anaerobic digestion of a mixture of plant material and organic waste allows better matching of organic waste and plant material feed supplies for year round operation. The process of this invention results in digester effluent which is easily dewatered and has a low concentration of soluble organics, providing easy disposal and recycling to the digester. The process of this invention may be used for methane production from plant material which is, by itself, recalcitrant to anaerobic digestion.

A process for improved gas production and accelerated stabilization of landfills by accelerated in situ bioleaching of organic wastes by acid forming bacteria in substantially sealed landfills, passing the leachate of hydrolysis and liquefaction products of microbial action of the microorganisms with the organic material to an acid phase digester to regenerate the activated culture of acid forming microorganisms for recirculation to the landfill, passing the supernatant from the acid phase digester to a methane phase digester operated under conditions to produce methane rich gas. The supernatant from the methane phase digester containing nutrients for the acid forming microorganisms and added sewage sludge or other desired nutrient materials are circulated through the landfill. Low Btu gas is withdrawn from the acid phase digester while high Btu gas is withdrawn from the methane phase digester and may be upgraded for use as SNG. The process of this invention is applicable to small as well as large organic waste landfills, provides simultaneous disposal of municipal solid waste and sewage sludge or other aqueous organic waste in a landfill which may be stabilized much more quickly than an uncontrolled landfill as presently utilized.

Gas production by accelerated in situ bioleaching of landfills

A two phase anaerobic digestion process in which an initial phase continually receives an organic feed for short detention times of less than two days under conditions which efficiently liquefy and breakdown the feed to lower molecular weight acids and other intermediates for conversion to methane. A succeeding phase is operated to treat the lower molecular weight acids and intermediates for detention times of about two to about seven days under conditions which efficiently lead to production to methane. The feed is loaded in the first phase at rates from about one to about ten pounds of total organics per cubic foot per day; and the products from the initial phase are loaded in the succeeding phase at rates of about 0.1 to about 0.5 pounds total organics per cubic foot per day.

Two phase anaerobic digester system

A process for production of methane gas in higher yields and higher rates by thermophilic or mesophilic anaerobic digestion of plant material and/or organic waste in admixture with an extract of different plant material. Increases of methane yield of greater than about 25% and up to about 500% are obtained by addition of the extract of different plant material to a normally low biodegradable plant and/or organic waste material before anaerobic digestion thereof. The resulting methane yields and production rates are higher than those obtained by the sum from anaerobic digestion of the individual components when using the extract as taught by this invention.

Methane production by anaerobic digestion of plant material and organic

An improved digestion process applicable to aerobic and anaerobic digesters is provided for waste treatment facilities during normal and overload conditions. The digestion system utilizes the addition of a lactobacillus fermentation product in a concentration sufficient to improve the digestion of units without deleteriously affecting the digestion system during normal load conditions. In addition, the use of the lactobacillus fermentation product facilitates recovery of digester systems from sour digestion conditions ('stuck digesters') in relatively short periods of time. Further, the ability of the digestion system to operate at higher-than-normal loadings and lower-than-normal detention times permits the use of existing facilities at not only peak periods which would otherwise be subjected to overloadings, but to be able to actually operate a system at twice designed loading, thus allowing for increased digester system capacity without incurring new capital equipment costs.

Anaerobic digestion of waste and biomass by use of lactobacillus culture

A process for recovering underground fossil fuel deposits retained in an inorganic matrix wherein the deposit is contacted with an aqueous medium of anaerobic microorganisms for a time sufficient to produce particles of the deposit containing both the organic fossil fuel and inorganic matrix of a size capable of forming a slurry with the aqueous medium for pumping to the ground surface. At the ground surface, the particulates are separated from the aqueous medium of anaerobic organisms, the particulates further processed by efficient surface techniques to separate the organic carbon and hydrocarbon component from the inorganic matrix. The aqueous medium of anaerobic organisms is recycled to the underground fossil fuel deposit for further production of the slurry forming particles of the deposit. Spent inorganic matrix may be added to the aqueous medium of anaerobic organisms to provide solid support and nutrient for the organisms and to maintain the desired pH. Such use of the spent inorganic matrix provides a useful service for the waste from the organic carbon and hydrocarbon recovery process. The anaerobic organisms may also form gaseous hydrocarbons during contact with the underground fossil fuel deposit.

Situ mining of fossil fuel containing inorganic matrices

A process for recovering underground fossil fuel deposits retained in an inorganic matrix wherein the deposit is contacted with an aqueous medium of anaerobic microorganisms for a time sufficient to produce particles of the deposit containing both the organic fossil fuel and inorganic matrix of a size capable of forming a slurry with the aqueous medium for pumping to the ground surface. At the ground surface, the particulates are separated from the aqueous medium of anaerobic organisms, the particulates further processed by efficient surface techniques to separate the organic carbon and hydrocarbon component from the inorganic matrix. The aqueous medium of anaerobic organisms is recycled to the underground fossil fuel deposit for further production of the slurry forming particles of the deposit. Spent inorganic matrix may be added to the aqueous medium of anaerobic organisms to provide solid support and nutrient for the organisms and to maintain the desired pH. Such use of the spent inorganic matrix provides a useful service for the waste from the organic carbon and hydrocarbon recovery process.

An improved two phase anaerobic digestion process in which an initial phase continually receives an organic feed for short detention times of less than two days under conditions which efficiently liquefy and breakdown the feed to lower molecular weight acids and other intermediates for conversion to methane. A succeeding phase is operated to treat the lower molecular weight acids and intermediates for detention times of about two to about seven days under conditions which efficiently lead to production of methane. The feed is loaded in the first phase at rates from about 1 to about 10 pounds of total organics per cubic foot per day; and the products from the initial phase are loaded in the succeeding phase at rates of about 0.1 to about 0.5 pounds total organics per cubic foot per day.

An improved anaerobic digestion of organic biomass by rupturing cells of microorganisms present in a digested biomass or untreated biomass fraction undergoing digestion to obtain a treated biomass fraction having liberated indigenous enzymes in place; and contacting such treated biomass fraction with an untreated biomass fraction so the combined fractions undergo improved anaerobic digestion. The cells in the untreated biomass portion are ruptured by conventional means such as sonication, and about equal volumes of the fractions are preferably combined under conditions of conventional anaerobic digestion.

Growing community of inventors

Homewood, IL, United States of America

Sambhunath Ghosh