IMPROVEMENTS RELATING TO SEPTIC TANKS

摘要

A method of determining whether a septic tank containing a liquid and sludge or scum mixture needs to be emptied, comprising locating a sensor in the mixture wherein the sensor is adapted to measure a parameter which can be used to determining the depth of sludge or scum 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.