NOVELTY - Anaerobic treatment method of wastewater, involves using device. The device has tower vessel with steel cylindrical covering (10), one or more vertical cylindrical three-phase separator (12), hexagonal or octagonal-shaped grille water distributor (11), gas hydraulic pressure balancer or fire barrier (13), water inlet pipe (1), outlet pipe (4), accumulation zone for acidogenic bacteria and methanogenic bacteria and water inlet pump.    USE - The method is useful for performing anaerobic treatment of wastewater containing organic matter for producing methane gas.    ADVANTAGE - The method is environmentally-friendly, cost-effective and stable, converts wastewater containing large amount of organic matter, and utilizes device that is simple in mechanical structure.    DETAILED DESCRIPTION - Anaerobic treatment method of wastewater, involves using device. The device has tower vessel with a steel cylindrical covering (10), one or more vertical cylindrical three-phase separator (12) which is distributed uniformly at the top of the tower vessel, hexagonal or octagonal-shaped grille water distributor (11) that has an identical diameter with the tower vessel which is installed at the bottom of the vessel, gas hydraulic pressure balancer or fire barrier (13) which is arranged on the top of gas discharge tube (5) present at the top of the vessel, water inlet pipe (1) which is connected to the water distributor, outlet pipe (4) which is connected to the three-phase separator, accumulation zone for acidogenic bacteria and methanogenic bacteria which is separated in proper order on the top of the water distributor, and water inlet pump. The tower vessel has total height of 2-25 m and diameter of 0.5-20 m. The content of acidogenic anaerobic bacteria and methanogenic anaerobic bacteria in respective zones are 10-50 g/l, and the total height for both accumulation zones is 0.7-0.8 times the height of the tower vessel. The ratio of height of acidogenic bacteria accumulation zone to methanogenic bacteria accumulation zone is 1:1.8-2. The water inlet pump delivers wastewater at a stable flow rate of 60-400 m3/hour from the inlet pipe to the tower vessel, where processing water flow rises in a uniform distribution when passing the cross-section of the water distributor. The water flow increases and passes at the acidogenic bacteria accumulation zone on the top of water distributor and fully contacts with bacteria, where all the organic matter is converted to acetic acid based volatile organic acids. The treated water flow is continued to rise and pass the methanogenic bacteria accumulation zone to again fully contact the bacteria. The volatile organic acids are converted into methane gas and the organic matter in water is eliminated. The treated water flow is rose and passed three-phase separator after contacting methanogenic bacteria accumulation zone. The treated water is delivered out of the tower vessel through the outlet pipe, where methane gas is transferred by the gas hydraulic pressure balancer or fire barrier to methane unit, preferably boiler or internal combustion engine. The anaerobic process is started where water flow from the bottom of the tower vessel, rose up to three-phase separator, and completed at the outlet pipe of the separator.    DESCRIPTION OF DRAWING(S) - The drawing shows perspective view of anaerobic treatment device.    Water inlet pipe (1)    Outlet pipe (4)    Gas discharge tube (5)    Tower vessel with steel cylindrical covering (10)    Hexagonal or octagonal-shaped grille water distributor (11)    Vertical cylindrical three-phase separator (12)    Gas hydraulic pressure balancer or fire barrier (13)