Abstract: Method for sewage water treatment using suspended activated sludge where sewage water is supplied to the equalizing tank being then re-pumped to the activation tank from which is supplied to the post-sedimentation tank after the clearing process and from here, after the remaining sludge sedimentation, to the drainage. The activation process is automatically interrupted after a drop of the sewage water level in the equalizing tank below the minimum level setting and the excessive sludge is then pumped off from the activation tank. The sludge re-pumping is interrupted and the activation process restored owing to the subsequent raising of the sewage water level in excess of the operation level setting.