A density separator for waste material, comprising: - a tank for receiving waste material and intended for containing a fluid to separate waste material by density into floating waste material and settled waste material; - automatic feed means (18, 37) to feed waste material to the tank; - motorised conveyor belts (3, 4), each one with a chassis and a conveyor belt, to remove waste material from the tank; and comprising: - a floating waste material conveyor to extract floating waste material from the surface of the water; and - a settled waste material conveyor to extract settled waste material from the bottom of the tank; wherein it additionally comprises a blower-type sorting device, comprising: - an air turbine that provides an airflow; - a duct which receives the airflow from the turbine and branches into a riser duct and a discharge duct; and - a diffuser located below the automatic feed means (18, 37) and communicated with the riser duct to receive a first part of the airflow of the turbine and cause air to be expelled in the vertical or inclined direction, which raises more light-weight waste material (bags, PET bottles, papers); where the discharge duct transports a second part of the airflow, which causes air to be horizontally expelled to remove the light-weight waste material - once it is raised by means of the first flow - to a lateral pipe, preventing interferences with other heavier fractions of waste material, and characterized in that it additionally comprises a bottom cleaner, which in turn comprises: - a first worm screw which runs, preferably horizontally, at the bottom of the tank, collecting waste material; and - a second worm screw installed outside the tank and inclined to receive in the lower portion the waste material from the first worm screw and raise said waste material for its subsequent disposal; each worm screw (12, 13) comprising a casing and at least one coaxially rotational vane with certain clearance with respect to the casing to allow draining water from the waste material. - a tank for receiving waste material and intended for containing a fluid to separate waste material by density into floating waste material and settled waste material; - automatic feed means (18, 37) to feed waste material to the tank; - motorised conveyor belts (3, 4), each one with a chassis and a conveyor belt, to remove waste material from the tank; and comprising: - a floating waste material conveyor to extract floating waste material from the surface of the water; and - a settled waste material conveyor to extract settled waste material from the bottom of the tank; - an air turbine that provides an airflow; - a duct which receives the airflow from the turbine and branches into a riser duct and a discharge duct; and - a diffuser located below the automatic feed means (18, 37) and communicated with the riser duct to receive a first part of the airflow of the turbine and cause air to be expelled in the vertical or inclined direction, which raises more light-weight waste material (bags, PET bottles, papers); - a first worm screw which runs, preferably horizontally, at the bottom of the tank, collecting waste material; and - a second worm screw installed outside the tank and inclined to receive in the lower portion the waste material from the first worm screw and raise said waste material for its subsequent disposal;