Apparatus for anaerobic digestion of organic waste

Apparatus for anaerobic digestion of organic waste material comprising a container divided into three interconnected chambers situated one below another, and making up a composite cylindrical structure, each chamber having a base of generally funnel-like form, the chambers comprising an inlet chamber with an inlet for material to be treated, a mixing chamber below the inlet chamber, and a settlement chamber between the inlet and mixing chambers, a duct leading from the inlet chamber downwardly into the mixing chamber, said duct being connected at or near the centre of the funnel-like base of the inlet chamber, a transfer duct leading from the mixing chamber upwardly into the settlement chamber, said duct being disposed at or near the center of the funnel-like base of the settlement chamber, and extending from a level in the mixing chamber below the upper extremity thereof and said mixing chamber defining an upper zone above the level of the lower end of the transfer duct in which, in use, gas is trapped and at which a gas outlet is situated, a recirculation duct from the base of the settlement chamber leading downwardly from a position at or near the centre of the funnel-like base of the settlement chamber, into the mixing chamber for recirculating liquids from the settlement chamber into the mixing chamber, and the settlement chamber also defining an upper gas zone in which, in use, gas is trapped, and a further gas outlet being situated at this zone and the settlement chamber having an outlet for liquids below said upper gas zone.