PROCESSO E DISPOSITIVO PARA A DEPURACAO DE AGUAS RESIDUAIS EM FILTRO BIOLOGICO CONTENDO PARTICULAS MENOS DENSAS QUE A AGUA

摘要

The invention relates to a process for the purification of wastewater in a biological filter 1 containing particles which are less dense than water through which pass two simultaneous ascendant co-current flows of untreated water and oxygenated gas which enter respectively via the base 2 and an injector 3 located close to the base, characterized in that the filter comprises a lower fluidized bed zone 4 and an upper fixed bed 5 the particles of which comprise expanded materials, the particles in the fixed bed being at the same time of smaller size and of smaller bulk density than those in the fluidized bed.