Despite the demonstrated treatment efficiency of biofiltration, nitrogen remains a challenging pollutant to remove from urban stormwater runoff. This difficulty stems from the multiple forms in which nitrogen may be present, varying from bioavailable and inorganic to an array of largely uncharacterised organic compounds. Additionally, complex environmental influences on nitrogen transformation and removal processes affect nitrogen removal efficiency. An experiment with 245 biofilter columns of varied design indicated nitrate dictated performance variation during wet periods, suggesting differing rates of nitrification, denitrification or plant uptake. In dry months, organic nitrogen removal was additionally problematic, but displayed minimal variation between treatments. The results suggest that alternative biofilter design features are required to facilitate microbial processing of re-released organic nitrogen from plants.


Republished in part with permission from  Payne, E. G. I., Pham, T., Hatt, B. E., Fletcher, T. D., Cook, P. L. M. and Deletic, A. (2013). Stormwater biofiltration - the challenges of inorganic and organic nitrogen removal. In:  Water Sensitive Urban Design 2013: WSUD 2013. Barton, ACT: Engineers Australia, pp. 153-160.

Note: Journal articles and conference papers (and links where available) are available under open access arrangements where possible. Otherwise please contact your institution’s library, the authors, or publishers to organise full access.

Last updated: 11th Apr 2017