The potential use of natural and constructed wetlands to treat rural and urban wastewaters and run-off has been under active investigation in Australia by the authors and others associated with them for about 15 years. The results of these investigations will be briefly summarised in relation to factors affecting their performance and their application for management of water pollution.
Investigations have included rigorous experimentation with wetland microcosms, calculation of nutrient balances for natural and artificial wetlands, fundamental research on the role of wetland plants, the construction of experimental wetlands of various designs at a pilot scale, and the installation of operating systems.
The results confirm the potential of wetland systems to ameliorate water quality but do not demonstrate how to do this consistently under normal day-to-day operating conditions. Issues that now need to be addressed include hydraulic short-circuiting, the role and management of the wetland plants, the extent to which constructed systems should mimic natural systems, and problems associated with scaling up from successful experimental systems to full scale operating treatment plants.