1. Definition of septage

1.1 Sewage sludge in the strict sense

Faecal matter is the residue left over from the treatment of individual wastewater systems. They are initially discharged into pre-treatment facilities, which are :

• septic tanks, which receive and pre-treat only black water;

• all-water pits, which receive and pre-treat black and grey water.

In exceptional cases, watertight pits are used to store black water only.

For septic tanks and all-water tanks, these materials come from :

• the decantation of suspended matter, whether organic or mineral;

• of the floaters that make up the cap...