The unit comprises collector (1) of input raw as e.g. outflow from stock-breeding farms or household waste water, pump (2), trap (3), heater (4) with mixing device (5), pumps (6,7), methane- tank (8) with driven spiral-blade mixer (9) for stirring of fermented sediment, gas-holder (10), collector-averager (11) connected to centrifuge (12) and collector-aerator (13), and control block (14). The collector (1) is in the form of a tank made of reinforced concrete with immersed pump (2) connected to electromotor (15). The pump (2) is through line (16) connected to trap (3) for separation to fractions, and through lines (17,18) to heater (4) and collector (1) for recirculation. The heater (4) is in the form of metallic electrically grounded reservoir with conic bottom, input (20) and output (21) pipe-joints. The heater contains electrohydraulic device (5) for mixing of sediment in the form of a perforated conducting cylinder. The methane-tank (8) is for anaerobic microbiological fermentation of preliminary neutralised and heated sediment, and for the production of biogas. The angular velocity of mixer (9) is 5-10 rev/min. The pressure excess at output of methane-tank (8) is 200-400 mm aqueous column, and the temperature is 33-35 C in mesophilic and 53-55 C in thermophilic fermentation modes. The time of processing in heater (4) is 10-30 min. The perforations of the conducting cylinder of the mixing device can be in the middle part. The drive of mixer in methane-tank can be a reversible d.c. electromotor.    USE -   The unit is used in biological treatment of liquids, in particular stock-breeding outflow and waste water, in bio-energetic devices for production of fertiliser, biogas and electrical energy for needs of plants and small settlements.    ADVANTAGE -   The unit has increased productivity, improved sanitaro-hygienic safety and reduced energy consumption due to electrohydraulic device and spiral-blade mixer which intensify the processes of neutralisation and fermentation.