Constructed wetlands are ecologically sustainable wastewater treatment options for water pollution control. Wetlands are complex ecosystems where an understanding of the interactions between abiotic and biotic components is fundamental to the treatment processes. Constructed wetland design involves the integration of engineering and ecological principles. Ecologists and engineers can work together to maximise the efficiency of constructed wetlands, planners and landscape architects' need to become involved to ensure that stormwater wetlands have a multi-functional role in the urban landscape.

The primary role of most constructed wetlands is water pollution control however, wetlands designed to treat stormwater in urban areas may have a multi-functional role - water pollution control, flood retention, landscape amenity, wildlife habitat creation, public recreation. Constructed wetlands are highly effective at removing TSS, BOD, nitrogen and pathogens, but phosphorus removal is variable. The treatment efficiency of a wetland system requires a balance between pollutant loading rate and hydraulic retention time, which is affected by the water quality and quantity of wastewater effluent or stormwater runoff. The size of a wetland will depend upon the volume of runoff, pollutant characteristics, desired level of treatment and the extent to which the wetland is expected to function as a flood retention basin. Constructed wetlands for tertiary treatment of sewage produce good water quality suitable for recycling.

This seminar will discuss the effectiveness of constructed wetlands for treating secondary sewage effluent and urban stormwater using case studies from subtropical Australia

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