Effluent purification process with post sedimentation step, includes anaerobic, anoxic and aerobic treatment steps

摘要

The process comprises at least one anaerobic treatment step, one anoxic treatment step and one aerobic treatment step for the effluent. A process for purifying effluent comprises at least two effluent treatment steps and a post-sedimentation step for the sludge from these treatment steps. At least the majority of the effluent is delivered under high hydraulic pressure to the second effluent treatment step and at least some of the sludge in one post-sedimentation treatment tank is supplied to the first effluent treatment step. The process comprises at least one anaerobic treatment step, one anoxic treatment step and one aerobic treatment step and the effluent is preferably treated in this order. An independent claim is also included for the process installation, comprising at least two treatment tanks for the effluent, and a supply for delivering effluent to them, the tanks being connected to each other so that a first sub-flow of effluent passes through all the tanks whilst a second sub-flow passes through only a portion of the tanks. A conduit is used to return sludge from a subsequent post-sedimentation tank (5) to the first effluent treatment tank. At least one anaerobic treatment tank (2), one anoxic treatment tank (3) and one aerobic treatment tank (4) are present.