Wetland plants for waste- and storm-water runoff treatment: management considerations

Abstract

Prediction of growth and nutrient dynamics of P. australis is critical in sustainable management of aquatic habitats and management of wastewater treatment facilities using reeds. Therefore, a mathematical model (Reed model) was developed and validated recently to simulate the growth and internal nutrient dynamics of any well-established, mono-specific freshwater stand of P. australis. The field study undertaken to investigate the ecology and best timing strategies of shoot harvesting, identified the seasonal changes of the quality of the rhizome reserves as essential for proper vegetation management. The simulated results of the present study showed that at the time of peak standing stock of minerals, shoots contain 40% and 22.5% of whole plant N and P, respectively. Further this showed the use of Phragmites in waste-water treatment allows removal of N more easily than P, because higher percentage of N is bound with the easily removable shoot parts. Since the model simulates the seasonal variation of nutrient contents in different organs, it enables one to plan the harvesting season of P. australis to maximize the mineral-nutrient removal and also to estimate the nutrient amount that can be removed via harvesting at a specific time.