“…The metal adsorption capacity of wetlands depends on many factors like concentrations of dissolved metals, dissolved oxygen (DO), air, pH, the alkalinity of AMD, active microbial biomass and the retention time of AMD in the wetland [22].The area of the wetland depends on the influent load entering the wetland. Aerobic wetlands are a good option for long-term treatment in low maintenance and operational costs [12], but these wetlands require longer detention time and huge surface area [22] for acid mine water treatment. The major factors that should be taken into account for design of a suitable wetland system vary upon site characteristics, are following: biochemical processes, seasons variation, authoritative issues, substrate, sediment control, the influent acidity loads and retention time ,morphometry , redox state & pH, slope of wetland, vegetation density, rate of flow of water and the land available for a wetland [23].…”