Nutrient Removal from Stormwater using Australian Native Plants in Constructed Floating Wetland

Stormwater pollution causes excessive nutrient influx to rivers and lakes, which can trigger algal bloom and subsequent damages to the freshwater ecosystem. Constructed Floating Wetland (CFW), a cost-effective technology, uses aquatic plants in a hydroponic system to strip nutrients from stormwater through plant uptake. In this study, performance of two native Australian plants such as Eleocharis acuta (EA) and Baumea preissi (BP) in removing nutrients (NH3-N, NO3-N, and PO4-P) was investigated. Experiments were conducted outdoor in microcosm (20L) buckets, including an unplanted control bucket. About 65% and 96% of Total Inorganic Nitrogen (NH3-N + NO3-N) was removed in 14 days by EA and BP, respectively. Both plants could remove up to 40% of PO4-P in the same duration. A significant difference (p<0.05) between control and planted buckets was detected in ANOVA analysis. First-order kinetic rates (k) for both plants revealed that BP (k=0.341, 0.099 and 0.044 per day) has higher kinetic rates than EA (0.174, 0.021 and 0.039 per day) for all nutrients (NH3-N, NO3-N and PO4-P), respectively. Elevated level of Dissolved Oxygen (DO) was observed in EA planted bucket, raising interest for further research. This study proved the suitability of CFW system to treat stormwater using Australian native plants.