The volume of sludge produced is influenced by how the unit is used (size, frequent overloads, type of wastewater, and routine maintenance. Each unit is different.
We estimate that an installation of 150 litres of water/p.e./ day will produce 0.5 litres of sludges/p.e./day, so 182,5 litres of sludges /p.e./year in the first year.
The volume of sludge produced will reduce over the first few years. Usually, after the 4th or 5th year, the sludge production is reduced by 40% and is closer to 0,3 litres of sludges/p.e./day.
When emptying, the cleaner must leave a few centimeters of sludge at the bottom of the tank as the bacteria that break down the sludge are specific and take a long time to develop.