REAKTORSYSTEM TIL GRANULÆRT SLAM OMFATTENDE EN EKSTERN SEPARATOR

The invention relates to a method for treating an aqueous fluid comprising a biodegradable organic substance in an installation comprising an upflow bioreactor containing a sludge bed, said sludge bed comprising biomass, and an external separator, comprising- feeding the aqueous fluid into a lower part of the bioreactor and forming biogas;- withdrawing the fluid from an upper part of the bioreactor, which withdrawn fluid comprises biomass;- feeding the aqueous fluid withdrawn from the upper part of the bioreactor into the external separator wherein the aqueous fluid comprising the biomass is separated into a liquid phase, and a fluid phase enriched in biomass; and- returning said fluid phase enriched in biomass from the external separator to the bioreactor.