IMMERSED FIXED BED BIOLOGICAL REACTOR AND METHOD FOR TREATING LIQUID EFFLUENTS

摘要

The invention concerns an immersed fixed bed biological reactor (1) comprising at least a vessel designed to be filled with effluents to be treated wherein are immersed bacteria supports (13). Said reactor which is equipped with aerating means (10) arranged in the lower part of the vessel is characterised in that the bacteria supports (13) have a specific surface not less than 100 m<2>/m<3>, preferably more than 125 m<2>/m<3> and percentage of void more than 90 %, preferably more than 95 %, said reactor having more or less the following additional characteristics: means (19) for providing a loop circulation of effluents inside at least one of the vessels are provided; the aerating means (10) are selected such that they are capable of generating in the medium, that is in the heavily polluted water, an oxygen concentration higher than 6 ppm, preferably higher than 7.5 ppm, means for neutralising the reaction medium acidity, that is regulating the pH value during the reaction process.