the ejector 4 because the working medium of the ejector is exhausted into the sewer pipe downstream of the ejector the pressure downstream of the ejector is somewhat above atmospheric pressure this higher pressure gives the waste that has passed the ejector 4 an extra push forward in the pipe 9 and it flows out into a municipal sewer 5 or other collecting duct which typically serves several buildings the pipe 9 preferably has a somewhat larger bore than the pipe 3 the cross section area of the bore of the pipe 9 being 70 to 100 larger than that of the pipe 3 the length of the pipe 3 between the toilet bowl 1 and the ejector 4 is about 6 m the angle between the end of the pipe 3 and the pipe 9 is about 150 u00b0 which is an advantageous value for ejectors of the type shown upstream of the ejector 4 at a distance of about 1 m or less therefrom there is a safety device 8 such as a sensitive safety valve or alternatively a device that stops the blower 10 should the pressure in pipe 3 rise above a threshold value the safety device 8 may also have both these.