The Imhoff septic tanks type marketed by CO.SPE.SA. They are constituted by a main tank which contains in its interior a secondary compartment ( sedimentation ) . L`affluente enters the sedimentation chamber , which is designed to retain solids and to allocate the sedimented material through l`apertura on the inclined bottom , the bottom compartment of digestion. It is proportioned in such a way as to ensure the right of retention time and to prevent phenomena of turbulence , caused by the water load , to decrease l`efficienza sedimentation . The fund is designed so that digestion takes place the biological stabilization of organic substances sedimented (fermentation or anaerobic digestion) . The Imhoff septic tanks type marketed by CO.SPE.SA. They are manufactured in compliance with CE