Aerobic versus anaerobic
Bacteria break down organic matter in two very different ways. With oxygen (aerobic), they produce water and carbon dioxide, both odourless. Without oxygen (anaerobic), they produce methane and hydrogen sulphide, among other things, which cause the typical soakaway smell.
Oxygen as the control parameter
A compressor supplies the bacteria with oxygen continuously. They work aerobically, the sludge stays in balance and no foul-smelling gases are produced. Compared with a closed, oxygen-poor septic tank, this is a fundamentally different system: a biological plant can sit in the garden without any noticeable smell.
In addition, the process stabilises the sludge biologically and considerably reduces how much builds up, so the tank does not need to be emptied every year.
When could it smell after all?
If the compressor fails (a power cut with no backup, faulty equipment), the plant switches to anaerobic mode after a few days. A wrongly sized plant (too small for the load) or a lack of maintenance can also cause odours in the long run. With maintenance that works, these cases are the rare exception, not the rule.
Odour-free as a brand promise
Being odour-free is, together with biological and chemical-free, one of our three core promises. Our pilot plant in Chile has been running since 2015 without faults and without any odour in the garden or the house. What lies behind it is biology, not advertising.
