| abstract |
The invention relates to a method for producing biogas and a biogas plant (1) for wet fermentation by use of nitrogen-rich, interfering-substance-laden input substrate (3) having an ammonium nitrogen concentration of more than 5 kg NH4-N/m3, wherein a first process stage (2) is provided for interfering-substance separation and a second process stage (12) is provided for the continuous formation of acetic acid and methane at a substantially stable temperature in the psychrophilic range. The invention further relates to a fermentation tank (5, 10, 18) of a biogas plant (1), wherein the fermentation tank (5, 10, 18) has a vertically arranged screw (25) provided with a rotary drive, which screw runs in a pipe (26) that is open at both ends and substantially fills up the pipe (26), wherein the pipe (26) extends from below the substrate level to above the bottom (22) of the fermentation tank (5, 10, 18) and is firmly connected to the fermentation tank (5, 10, 18). |