A device for treating an effluent composed of liquid and of solid particles to obtain a treated effluent includes a filtration device using gravity separation on a rotating cloth having an inlet intended to receive the effluent to be treated and a first and a second outlet, the filtration device being designed to separate the effluent into a first flow and a second flow, the second flow comprising sludges comprising solid particles, the first flow leaving the filtration device through the first outlet, the second flow leaving the filtration device through the second outlet, and at least one recirculation device designed to recirculate at least a part of the sludges of the second flow to the inlet of the filtration device, the second outlet being linked to the at least one recirculation device. A method for treating an effluent is also provided.