title: Co-optimisation of phosphorus and nitrogen removal in stormwater biofilters: the role of filter media, vegetation and saturated zone.
abstract: Biofilters have been shown to effectively treat stormwater and achieve nutrient load reduction targets. However, effluent concentrations of nitrogen and phosphorus typically exceed environmental targets for receiving water protection. This study investigates the role of filter media, vegetation and a saturated zone (SZ) in achieving co-optimised nitrogen and phosphorus removal in biofilters. Twenty biofilter columns were monitored over a 12-month period of dosing with semi-synthetic stormwater. The frequency of dosing was altered seasonally to examine the impact of hydrologic variability. Very good nutrient removal (90% total phosphorus, 89% total nitrogen) could be achieved by incorporating vegetation, an SZ and Skye sand, a naturally occurring iron-rich filter medium. This design maintained nutrient removal at or below water quality guideline concentrations throughout the experiment, demonstrating resilience to wetting-drying fluctuations. The results also highlighted the benefit of including an SZ to maintain treatment performance over extended dry periods. These findings represent progress towards designing biofilters which co-optimise nitrogen and phosphorus removal and comply with water quality guidelines.
authors.affiliation: CRC for Water Sensitive Cities, Water for Liveability Centre, Department of Civil Engineering, Monash University, Victoria 3800, Australia E-mail: bonnie.glaister@monash.edu.
authors.forename: Bonnie J
authors.initials: BJ
authors.lastname: Glaister
authors.affiliation: Waterway Ecosystem Research Group, Department of Resource Management and Geography, Melbourne School of Land and Environment, the University of Melbourne, Victoria 3121, Australia.
authors.forename: Tim D
authors.initials: TD
authors.lastname: Fletcher
authors.affiliation: CRC for Water Sensitive Cities, Water Studies Centre, School of Chemistry, Monash University, Victoria 3800, Australia.
authors.forename: Perran L M
authors.initials: PL
authors.lastname: Cook
authors.affiliation: CRC for Water Sensitive Cities, Water for Liveability Centre, Department of Civil Engineering, Monash University, Victoria 3800, Australia E-mail: bonnie.glaister@monash.edu.
authors.forename: Belinda E
authors.initials: BE
authors.lastname: Hatt
mesh_terms: D019149:Bioreactors; D005374:Filtration / Q000295:instrumentation* / Q000379:methods; D009584:Nitrogen / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*; D010944:Plants; D011891:Rain; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D009584:Nitrogen