IMPROVEMENTS RELATING TO SEPTIC TANKS

摘要

A method of determining whether a septic tank (1) containing a liquid and sludge or scum mixture needs to be emptied, comprising locating a sensor (28) in the mixture wherein the sensor is adapted to measure a parameter which can be used to determining the depth of sludge (27) or scum (21) in the septic tank and generating a warning signal when a signal from the sensor is indicative of a depth of sludge or scum exceeding a predetermined limit.