Arsenic removal during conventional aluminium-based drinking-water treatment

The changing forms and concentrations of arsenic through aluminium-based co agulation treatment processes were tracked for three drinking-water treatme nt plants. This has provided direct evidence of where and how arsenic is re moved. In general, soluble As(V) is converted to particulate As(V) by adsor ption during rapid mixing, and is removed along with naturally occurring pa rticulate arsenic predominantly by clarification. Soluble As(III) tracks th rough the treatment processes and is converted to soluble As(V) during fina l chlorination. The ability of a water treatment process to achieve the max imum acceptable concentration for arsenic in drinking water is dependent on the concentration of As(III) in the source water. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.