ABSTRACT
Natural treatment systems include land treatment (e.g. surface irrigation, subsurface irrigation, infi ltration-percolation and overland fl ow), macrophyte-based systems including fl oating macrophytes (e.g. duckweed, hyacinth ponds) and wetlands (e.g. reed beds), and stabilization ponds which are classed as either anaerobic lagoons or oxidation ponds (e.g. facultative ponds, maturation ponds and purifi cation lakes).
