Abstract: Method in combusting solid fuel in a first fluidized bed (11) and a second fluidized bed (12) located laterally of the first bed, said beds being mutually separated but communicating with each other. Fuel particles are transferred from the first bed to the second bed. The first bed is operated substoichiometrically and the second bed is operated with a large excess of air. Flue gas from the first bed is diverted in a common freeboard over the beds to be directed in counterflow towards the flue gas from the second bed. Heat power is recovered solely from the second bed.

Abstract: An apparatus for purification of waste water in a tank or a pool has a housing rotatably journalled on a raft and provided with pump means to force air and water therethrough. The housing contains first discs having central holes and a second discs having peripherical apertures at the wall of the housing. Each disc forms a baffle for air and water flows through the housing, thereby imparting a tortuous path to the air and water passing through the housing. The discs are corrugated and are arranged in a stack with the corrugations of adjacent discs oriented at right angles. The corrugations strengthen the discs and form support points at which the discs contact each other, and also define channels between the discs, through which channels of water and air can flow. A spiral pump rotating with the inlet end of the rotor forces metered volumes of water and air through the rotor.