Treatment system for acidic wastewater containing heavy metals

摘要

PROBLEM TO BE SOLVED: To provide a long-life cycle passive treatment type system for treating wastewater in which maintenance such as removal of iron precipitates inevitably generated during treating acid wastewater containing heavy metals mainly composed of iron is easily carried out.SOLUTION: The system includes the following components in this order: a trickling filter having a part filled with filter media, where, when trickled wastewater passes through the filled part, ferrous ions contained in the wastewater are oxidized into ferric ions; a sedimentation tank where primary treated water flowing down from the trickling filter and containing ferrous ions is made to reside for a certain time to cause the ferric ions to be precipitated and to be settled, and its supernatant is enabled to flow out as secondary treated water; a calcic water channel where block-shaped limestones are provided on the bottom in advance to neutralize the secondary treated water, and gates each of which upper veranda is served as a flow-out part for tertiary treated water are provided; and an aerobic artificial marsh where an ecological zone with a constant depth of water is provided and a precipitate deposition zone of which water depth is deeper than that of the ecological zone is provided beneath the flow-out part of the calcic water channel in series with the ecological zone.