Comparative life cycle assessment of aerobic treatment units and constructed wetlands as onsite wastewater treatment systems in Australia

Abstract Life Cycle Assessment was used to evaluate onsite wastewater treatment systems (OWTS): aerobic unit (ATU) with reinforced concrete (C.ATU) and HDPE (H.ATU) tank; constructed wetland (CW) three biochar concentrations in the substrate (0%; 10, 20% v:v), dubbed CW.BC0, CW.BC10 CW.BC20, respectively. CML 2001 SimaPro® impacts of 1 m3 wastewater. The OWTS were compared on their overall environmental performance scores (OEP). ATUs have higher human toxicity, eutrophication, freshwater marine ecotoxicity. CW.BC20 has lowest global warming impact (GWP) while CW.BC0 highest. Electricity consumption largest contributor ATUs. PVC pipes, coir peat, geomembrane, electronic devices biggest contributors CWs. OEP CWs almost a third ATUs’ (6.07E-03). Changes electricity sources tested according 2030-Australian targets; increasing renewables share improves by 39%; nevertheless, continue outperform Variations biodegradation had small effect CWs; being relevant only GWP. This study provides reference policy makers for better evaluation OWTS.