title: Life Cycle Assessment modelling of stormwater treatment systems.
abstract: Stormwater treatment technologies to manage runoff during rain events are primarily designed to reduce flood risks, settle suspended solids and concurrently immobilise metals and nutrients. Life Cycle Assessment (LCA) is scarcely documented for stormwater systems despite their ubiquitous implementation. LCA modelling quantified the environmental impacts associated with the materials, construction, transport, operation and maintenance of different stormwater treatment systems. A pre-fabricated concrete vortex unit, a sub-surface sandfilter and a raingarden, all sized to treat a functional unit of 35 m(3) of stormwater runoff per event, were evaluated. Eighteen environmental mid-point metrics and three end-point 'damage assessment' metrics were quantified for each system's lifecycle. Climate change (kg CO2 eq.) dominated net environmental impacts, with smaller contributions from human toxicity (kg 1,4-DB eq.), particulate matter formation (kg PM10 eq.) and fossil depletion (kg oil eq.). The concrete unit had the highest environmental impact of which 45% was attributed to its maintenance while impacts from the sandfilters and raingardens were dominated by their bulky materials (57%) and transport (57%), respectively. On-site infiltrative raingardens, a component of green infrastructure (GI), had the lowest environmental impacts because they incurred lower maintenance and did not have any concrete which is high in embodied CO2. Smaller sized raingardens affording the same level of stormwater treatment had the lowest overall impacts reinforcing the principle that using fewer resources reduces environmental impacts. LCA modelling can serve as a guiding tool for practitioners making environmentally sustainable solutions for stormwater treatment.
authors.affiliation: Department of Civil and Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand.
authors.forename: Aisling D
authors.initials: AD
authors.lastname: O'Sullivan
authors.affiliation: Department of Civil and Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wicke
authors.affiliation: Civil and Environmental Engineering Department, South Dakota School of Mines and Technology, Rapid City, SD, USA.
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Hengen
authors.affiliation: Civil and Environmental Engineering Department, South Dakota School of Mines and Technology, Rapid City, SD, USA.
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Sieverding
authors.affiliation: Civil and Environmental Engineering Department, South Dakota School of Mines and Technology, Rapid City, SD, USA. Electronic address: james.stone@sdsmt.edu.
authors.forename: James J
authors.initials: JJ
authors.lastname: Stone
mesh_terms: D057231:Climate Change; D003247:Conservation of Natural Resources / Q000379:methods*; D004777:Environment; D005579:Fossil Fuels / Q000032:analysis; D006801:Humans; D008962:Models, Theoretical; D052638:Particulate Matter; D011891:Rain; D014872:Water Movements; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D005579:Fossil Fuels; D052638:Particulate Matter
keywords: Concrete; Life Cycle Assessment; Raingardens; Sandfilter; Stormwater; Sustainable design