Patent ID: 7147776
Filing Date: 2006-12-12
Classification: C02F,Y02W

Abstract:
1. A process for the biological treatment of an effluent in order to purify it, comprising a first treatment of the majority of said effluent in a first step of anaerobic biological treatment by the way of a biomass is fixed onto a mobile support, giving a first effluent, the biomass present in the first step comprising at least sulfate-reducing bacteria, followed by a second treatment of the majority of the first effluent, in a second step of anoxic biological treatment, by the way of a fixed biomass, giving a second effluent, the biomass present in the second step comprising at least sulfur-oxidizing bacteria, and finally a third treatment of the majority of the second effluent in a third step of aerobic biological treatment, by the way of a fixed biomass, giving a third purified effluent, the biomass present in the third step comprising at least nitrifying bacteria, wherein the process also comprises recycling of some of the effluent present in the third step into the second step.