NOVELTY - The biogas plant comprises: gas and liquid tight sealable fermenters (1) for biomass; a biogas removal opening (2) provided in the fermenters; a percolate collection unit (6) comprising a percolate storage (3); a percolate removal device (4) that is provided in each fermenter and conveys the produced percolate to the percolate collection unit and percolate collection chambers arranged at a height below a bottom of the fermenters; and a percolate distributor (5), which distributes the percolate from the percolate collecting unit.    USE - The biogas plant is useful for methanation of non-pumpable biomass to produce biogas (all claimed).    ADVANTAGE - The biogas plant reliably prevents the damming of the percolate in the fermenter using the percolate collecting unit, thus economically performing the methanation of the non-pumpable biomass.    DETAILED DESCRIPTION - The biogas plant comprises: gas and liquid tight sealable fermenters (1) for biomass; a biogas removal opening (2) provided in the fermenters; a percolate collection unit (6) comprising a percolate storage (3); a percolate removal device (4) that is provided in each fermenter and conveys the produced percolate to the percolate collection unit and percolate collection chambers arranged at a height below a bottom of the fermenters; and a percolate distributor (5), which distributes the percolate from the percolate collecting unit. The percolate collecting chambers are connected to each other by percolate bonding conductors. Openings of the bonding conductors in the collecting chambers are lower than the bottom of the fermenters. The percolate bonding conductors are percolate balancing cables. A filling level sensor in the form of a pressure sensor is arranged in the percolate collection unit at a height below the top edge of the bottom of the fermenter. The percolate removal device comprises a collecting channel. The openings: are formed below the level of the percolate removal device, preferably the bottom of the percolate removal device; and are formed above the height of a suction opening of a pump in the collecting chambers. The pump and/or a valve and the pump and/or a valve controller are arranged in the percolate collection unit. The percolate removal device comprises a check valve, which prevents the back-flow of percolate across the percolate removal device. The percolate removal device is aligned to or below the bottom of the fermenter with its upper edge. The suction opening of the pump is formed below the level of the bottom of the fermenter. At any point of the percolate bonding conductors, the highest point of a cross section is lower than the lowest point of the cross section at any point of the percolate balancing cables, or all percolate collecting chambers are connected via separate gas-bonding conductors whose openings are higher than the highest opening of the percolate bonding conductors. An INDEPENDENT CLAIM is included for a process for the production of biogas.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a biogas plant.    Gas and liquid tight sealable fermenters (1)    Biogas removal opening (2)    Percolate storage (3)    Percolate removal device (4)    Percolate distributor (5)    Percolate collection unit. (6)