The present invention relates to a sewer system comprising a sewage receptacle (1), sewer piping (3) connected to the sewage receptacle by means of a discharge valve (2), a vacuum generating means (4) for generating vacuum in the sewer piping, a control mechanism (5) for controlling the discharge valve, and a vacuum buffer means. In order to provide a small volume vacuum buffer means that may provide a timely raising of the vacuum level available for the control mechanism (5), the vacuum buffer means comprises an active buffer device (10) in fluid communication with the control mechanism (5) and the sewer piping (3).