A multi-stage anaerobic digester is designed to treat a high solids, stackable feedstock. The system may also receive a pumpable feedstock such as a slurry or sludge. In a first stage, the digestate circulates in one direction around a raceway such that the digestate may pass a feed inlet multiple times before leaving the first tank. An optional side stream loop withdraws fibrous material from near the top of the reaceway and return digestate with chopped fibers, preferably lower and further along the raceway. An outlet from the raceway located near, but upstream of the feed inlet discharges partially digested substrate to a second stage, which is operated as a stirred tank reactor. The two stages may be provided in a single tank with an internal wall separating a ring shaped outer portion from a cylindrical inner portion. The digester may be operated in a thermophilic temperature range.

Disclosed is a bioreactor, especially a plug flow bioreactor, including an agitator running along a longitudinal axis for thoroughly mixing a dry solid biomass that is to be outgassed in a fermentation chamber. In said bioreactor, an agitator shaft is mounted exclusively in two opposite end walls of the fermentation chamber while at least one free end of the agitator is connected to a drive unit outside the fermentation chamber.

A process and system for producing a synthetic hydrocarbon having a desired H/C ratio is disclosed. Organic material is biochemically digested in a two stage biodigester for separately producing a hydrogen containing biogas substantially free of methane in a first stage and a methane containing biogas in a second stage. The methane containing biogas is reformed in a first reformer to generate hydrogen gas and carbon monoxide gas, which are then combined in a mixer with the hydrogen containing biogas into a syngas in amounts to achieve in the syngas an overall H/C ratio substantially equal to the desired H/C ratio. The syngas is reacted with a catalyst in a second reformer, a Fischer-Tropsch (FT) reactor, to produce the hydrocarbon. Using a two stage biodigester allows for the generation of separate hydrogen and methane streams, a more economical generation of the FT syngas and reduced fouling of the FT catalyst.

A mixing device for an application in a container including a rotatable shaft; a drive device through which the rotatable shaft is drivable; and at least one mixing element arranged at the shaft, wherein the mixing element is rotatable together with the shaft, wherein the shaft includes a support device connected with the shaft, wherein the support device is arranged in an end portion of the shaft that is oriented away from the drive device, wherein the shaft is rotatable about its longitudinal axis relative to the support device, wherein the mixing device is supportable through the support device in a receiving device connected with the container, wherein the support device is moveable by a straight bearing or a rolling element bearing along a guide device into the receiving device, wherein the straight bearing includes at least one sliding surface that is moveable on a corresponding sliding surface.

A process for reducing the production of sludge by municipal or industrial wastewater purification plants, comprising a step of mesophilic or thermophilic anaerobic digestion (20), or anaerobic digestion combining these two operating modes, of a stream of sludge to be treated (1), and at least one biological solubilization anaerobic treatment step (30); the process comprises, upstream of the anaerobic digestion step, a step of dehydration (10) of the sludge to be treated, followed by a step of mixing (15) the dehydrated sludge with a recirculated fraction of sludge that is more liquid, originating from recycling of the digestion (20), and/or from the anaerobic treatment step (30), and/or centrates originating from a final dehydration (50) of the treated sludge, wherein the recirculation rate is chosen such that the mixture has a dryness suitable for digestion, this mixture then being directed towards the digestion.

A large-type horizontal device and a method for continuous methane fermentation belong to dry biogas fermentation technology. The whole distribution of a fermentation compartment uses a U-shape plane layout which is a snap-back type and uses a material propeller. The material propeller has two axes and two blades and is constantly occluded with counter rotation. The irreversible propulsion of materials can be realized through counter rotation of two occluded blades. The propeller is set at the bottom of the main partition of the fermentation compartment. Since the impeller blades adopt a long side design in rotation axis directions, a large amount materials can be propelled. The propel ability of propeller can be changed through changing of rotation speed. Counter rotation of two occluded blades can realize material propeller without material reverting. The inlet and outlet entrances of the reactor in the disclosure are near to the ground and can be operated conveniently to, therefore, save energy. The homogeneous output of materials and entire plug-flow can be realized at the same time without material mixing in the whole process. This makes fermentation more complete.

Provided is a non-linear model predictive control (NMPC) system for automatic and optimum start-up of an anaerobic digestion (AD) system. The NMPC provides an optimum set of values of manipulated variables for controlling some of the key AD process variables during start-up. The NMPC based automatic start-up system was evaluated against a virtual AD process plant scenario involving a high rate AD reactor treating a readily biodegradable carbohydrate based substrate.

Disclosed is a method for the culture of photosynthetic organisms selected from among microalgae, cyanobacteria and macroalgae using a continuous or discontinuous CO2 source.

A system to process a waste food includes a housing; at least one drum enclosed in the housing where the waste food is mixed up and digested by microorganisms or dehydrated; and at least one cleaner incorporated in or on the machine to permit a jet of water to be turned on and off to clean the drum.

A portable and modular renewable energy microgeneration apparatus is disclosed that includes at least four modular units. The first modular unit includes a mixing tank and a chopper. The second modular unit includes a buffer tank, a liquor tank, and a pasteurization tank that pasteurizes waste that has been mixed with liquid from the liquor tank by the mixer, chopped into smaller sized components by the chopper, and pre-warmed by the buffer tank. The third modular unit includes a digestion tank that performs anaerobic digestion on pasteurized waste received from the pasteurization tank. And the fourth modular unit includes a gas storage tank that stores gas generated by the waste in at least one of the mixing tank, the chopper, the buffer tank, the liquor tank, the pasteurization tank, and the digestion tank. Each of the four modular units is both portable and modular.