Floating and removable material is extracted from domestic wastewater in mechanical septic tanks. This is pure mechanical cleaning, for which you need 500 ltrs of capacity per inhabitant. If you assume a volume of 150 ltrs, the wastewater passes through the system in 3 days. These septic tanks must have a total volume of at least 2000 ltrs. A 2000 ltr system is sufficient for 4 inhabitants, another 500 ltrs, must be incorporated for each additional inhabitant. • Low weight: can also be installed in difficult local conditions without a crane • Reasonable purchase and installation costs. • Low maintenance: maintenance or cleaning work can be performed through the access shaft.