Abstract: The invention relates to an apparatus for the conversion into biogas of fermentation stillage arising as a waste product of ethanol production. This apparatus comprises a separation unit for the separation of the fermentation stillage into a thin fraction and a thick fraction, at least one biogas reactor for fermenting the thin fraction and/or the thick fraction, and a storage tank. According to a first aspect of the present invention, two biogas reactors are provided, to separate the thin fraction and the thick fraction independently of one another. According to a second aspect of the present invention, a nitrogen sink is provided downstream of the storage tank to provide, from the reactor effluent, process water with low or no nitrogen content which may then be fed to the reactor and/or the bioethanol plant. According to a third aspect the invention is characterized by a combination of a single-stage separation unit and a heavy-duty biogas reactor with a pore-free flow path.

Abstract: The process according to the invention for the microbial production of a specific product and methane comprises the following steps: a) the production in a bioreactor (2, 10) of a specific product from a specific substrate using a specific organism, the producer, wherein during the production of this product metabolites such as e.g. low-molecular alcohols, aldehydes and acids, hydrogen and CO2, which may inhibit the production of the product, are obtained; and b) the production of methane by means of a methanogen, wherein in the production of the methane at least one metabolite is decomposed and by this means removed from the bioreactor (2, 10) and its energy is made usable.

Abstract: The invention relates to a trace element solution for the supplementing of nutrients for an anaerobic fermentation, in particular a biogas process, comprising at least one trace element and at least two complexing agents. Complexing agents are used which (1) are able to transport the trace elements in complexed form across the cell membrane and which (2) release the trace elements in the cell. Where applicable, the complexing agents are biologically decomposable.

Abstract: The process according to the invention for the microbial production of a specific product and methane comprises the following steps: a) the production in a bioreactor (2, 10) of a specific product from a specific substrate using a specific organism, the producer, wherein during the production of this product metabolites such as e.g. low-molecular alcohols, aldehydes and acids, hydrogen and CO2, which may inhibit the production of the product, are obtained; and b) the production of methane by means of a methanogen, wherein in the production of the methane at least one metabolite is decomposed and by this means removed from the bioreactor (2, 10) and its energy is made usable.

Abstract: The invention relates to an apparatus for the conversion into biogas of fermentation stillage arising as a waste product of ethanol production. This apparatus comprises a separation unit for the separation of the fermentation stillage into a thin fraction and a thick fraction, at least one biogas reactor for fermenting the thin fraction and/or the thick fraction, and a storage tank. According to a first aspect of the present invention, two biogas reactors are provided, to separate the thin fraction and the thick fraction independently of one another. According to a second aspect of the present invention, a nitrogen sink is provided downstream of the storage tank to provide, from the reactor effluent, process water with low or no nitrogen content which may then be fed to the reactor and/or the bioethanol plant. According to a third aspect the invention is characterised by a combination of a single-stage separation unit and a heavy-duty biogas reactor with a pore-free flow path.

Abstract: An air bearing slider for supporting a transducer is provided with a pair of rails having an air bearing surface with a continuously curved part with its greatest width at the leading end of the slider. In the rear area of the slider the air bearing surfaces are of equal width. The invention furthermore provides a mechanical grinding process using a grinding wheel having two grinding disks separated by a spacer disk and provided with bevelled grinding surfaces on its inner sides. Either by advancing the turning grinding wheel parallel to the surface of the slider from the trailing towards the leading end up to a certain point or in accordance with another embodiment by tilting the slider slightly towards the advance motion and continuously advancing the grinding wheel, the continuously curved air bearing surface portions are provided in a simple and efficient manner.