Studies on pollutant removal from stormwater by Budjong Creek Wetland, Lake Illawarra, New South Wales

This study on the effectiveness of the Budjong Creek Constructed Wetland for removing pollutants from stormwater runoff was conducted over a 13 month period. Starting in the beginning of January 2007 and concluding at the end of February 2008; a number of both wet and dry samples were taken. These samples were analysed for total dissolved nitrogen and dissolved nitrogen species, NOx and NH4+, total dissolved phosphorus and orthophosphate, total suspended solids. Multimeter datasonde measurements were taken and rainfall statistics were calculated. The results of the measurements and analysis were correlated and one-way ANOVA tests were performed to determine significant relationships within the wetland and between data sets. The results show that the creek catches much of the incoming stormwater allowing phosphorus to settle out of the water column and the wetland acts to transform nitrogen species. Total dissolved nitrogen had a removal efficiency of about 5%, while nitogenous oxides removal was high at 84%. The wetland also exports 88% more phosphorus from the water column than it takes in at the start of the wetland.