(DE4143229-A1)      In heated rectangular fermenter for recovering biogas from animal slurry, wall standing on the floor of the fermenter and extending from one end wall but stopping short of the opposite end wall, reverses the flow of the slurry. The slurry inlet is on one side of the wall, and the outlet on the other, both being near the floor. Slurry passes through three heating zones with heating elements and which act as pre-fermenting zone, principal fermenting zone and post-fermenting zone.    The zones are kept at 30-39 deg. C and below the heating elements are pneumatic conveying nozzles. The heating and pneumatic pressure may be provided from the energy in the recovered gas. The height of the wall is 1/3 to 2/3 of the height of the fermenter, and it is covered at a distance above the liq. surface with strong foil dome which acts as gas storage vessel. The edges of this dome are attached to the fermenter walls below the liq. level, and has a gas outlet at its highest point.    USE/ADVANTAGE -   Used in recovering biogas from animal slurry, farmyard manure etc. Ensures a thorough fermentation process, uses little energy, and can be installed so as to provide little physical obstruction. It is economic to produce, is not sensitive to disturbances, and has very long useful life.    (EP501376-A3)      In a heated rectangular fermenter for recovering biogas from animal slurry, a wall standing on the floor of the fermenter and extending from one end wall but stopping short of the opposite end wall, reverses the flow of the slurry. The slurry inlet is on one side of this wall, and the outlet on the other, both being near the floor of the fermenter and close to the end wall. The flow of the slurry passes through three heating zones with heating elements and which act as pre-fermenting zone, principal fermenting zone and post-fermenting zone. These zones are kept at 30-39 deg.C and below the heating elements are pneumatic conveying nozzles. The heating and pneumatic pressure may be provided from the energy in the recovered gas. The height of the wall is 1/3 to 2/3 of the height of the fermenter, and it is covered at a distance above the liq. surface with a strong foil dome which acts as a gas storage vessel. The edges of this dome are attached to the fermenter walls below the liq. level, and has a gas outlet at its highest point.    USE/ADVANTAGE -   Used in recovering biogas from animal slurry, farmyard manure etc. Ensures a thorough fermentation process, uses little energy, and can be installed so as to provide little physical obstruction. It is economic to produce, is not sensitive to disturbances, and has very long useful life