Stray particles as the source of residuals in sand filtrate: Behavior of superfine powdered activated carbon particles in water treatment processes

Although superfine powdered activated carbon has excellent adsorption properties, it is not used in conventional water treatment processes comprising coagulation–flocculation, sedimentation, and sand filtration (CSF) due to concerns about its residual treated water. Here, we examined the production fate of very fine particles with lacking charge neutralization as a source filtrate after CSF treatment. Almost all were charge-neutralized by coagulation rapid mixing, but small amount (?0.4% initial concentration) lesser degree left behind process. Such particles, defined stray hardly removed subsequent flocculation sedimentation processes, some them remained filtrate. The concentration varied similarly that particles. smaller than before treatment, had less turbidity samples collected was correlated filtrate, even though often an indicator performance respect removal suspended matter. Based on these findings, suggest reduction should be goal Examining this concept further, confirmed residence time distributions reactors influenced then particle found effect dependent coagulant type. A multi-chambered-reactor configuration lowered both compared single-chambered reactor configuration. When normal basicity PACl consisted mainly monomeric Al species used, decreased during process gradually because transformed colloidal via polymeric species. In contrast, when high-basicity mostly largely concentration, which did decrease further These findings will valuable for controlling