Abstract: The present invention relates to a method for chemically modifying a reactant using microbes. The method includes providing a particulate material which includes a plastic carrier and microbes attached to the carrier. The particulate material is dispersed in a dispersing fluid and has a specific gravity less than that of the dispersing fluid. When the microbe is anaerobic the particulate material has an operating interfacial surface area of from about 2,000 to about 240,000 square meters per cubic meter of reactor volume. When the microbe is aerobic the particulate material has an operating interfacial surface area of from about 1,000 to about 30,000 square meters per cubic meter of reactor volume. The method further includes establishing a flow of the reactant through the particulate material effective to contact the reactant with the microbes for a time sufficient to chemically modify the reactant. Use of the methods in wastewater treatment, aquaculture fish production, and ethanol production are disclosed.

Abstract: A biological treatment method for water containing nitrogen and phosphorus is provided. Treatment is carried out by contacting the water with one or more substituted or unsubstituted hydrocarbon compounds each having from 1 to 6 carbon atoms in the presence of methanotrophs and/or aerobic heterotrophic bacteria under process conditions effective to reduce soluble nitrogen and soluble phosphorus levels in the water each to below about 1 mg/L.

Abstract: A method is disclosed for the chemical detoxification of anaerobically digested organic sludge containing toxic heavy metals in insoluble form. A quantity of the sludge is transferred from a conventional anaerobic digester to an insulated reactor vessel where the sludge is mixed and aerated at a rate sufficient to raise the oxidation reduction potential of the sludge to above +300 mv. and to maintain this condition for a period of 6-12 hours during which the heavy metals are converted to their desired oxidation state. The sludge is then acidified under controlled conditions to pH 1.0-3.0 for a period of 6-12 hours to solubilize the heavy metals. Conventional dewatering techniques are used to separate the detoxified, acidic sludge and the acidic, heavy-metal-containing water. The sludge may be neutralized for safe land application, and the metals can be recovered from the water using existing conventional techniques.

Abstract: A method for purifying wastewater of biodegradable organics by converting the organics to methane and carbon dioxide gases is disclosed, characterized by the use of an anaerobic attached film expanded bed reactor for the reaction process. Dilute organic waste material is initially seeded with a heterogeneous anaerobic bacteria population including a methane-producing bacteria. The seeded organic waste material is introduced into the bottom of the expanded bed reactor which includes a particulate support media coated with a polysaccharide film. A low-velocity upward flow of the organic waste material is established through the bed during which the attached bacterial film reacts with the organic material to produce methane and carbon dioxide gases, purified water, and a small amount of residual effluent material. The residual effluent material is filtered by the film as it flows upwardly through the reactor bed.

Abstract: A method is disclosed for the combined biological-chemical detoxification of municipal sewage sludge. A slurry of thickened primary sludge and secondary waste-activated sludge is fed to an enclosed insulated reactor vessel. The slurry is aerated with ambient air by a self-aspirating aerator to achieve autoheating of the slurry to thermophilic temperatures by the conservation of the metabolic heat of microbiological oxidation of the biodegradable organic material present in the slurry. The slurry is retained in the reactor for a period of time sufficient to destroy pathogenic bacteria and to increase the oxidation reduction potential of the biological reactor contents for the conversion of heavy metals to their desired oxidation state, following which the autoheated slurry is acidified to pH 1.0-3.0 for 6 to 12 hours to solubilize the heavy metals. Conventional dewatering techniques are used to separate the detoxified, acidic sludge and the acidic, heavy-metal-containing water.