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

Life Cycle Assessment was used to evaluate onsite wastewater treatment systems (OWTS): aerobic treatment unit (ATU) with reinforced concrete (C.ATU) and HDPE (H.ATU) tank; and constructed wetland (CW) with three biochar concentrations in the substrate (0%; 10, and 20% v:v), dubbed CW.BC0, CW.BC10 an...

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Autores principales: Giovani Rodolfo Alatrista Gongora, Ray Hangyong Lu, Ali El Hanandeh
Formato: article
Lenguaje:EN
Publicado: IWA Publishing 2021
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Acceso en línea:https://doaj.org/article/f741a60dd38f4c53972ce58a233613e6
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Sumario:Life Cycle Assessment was used to evaluate onsite wastewater treatment systems (OWTS): aerobic treatment unit (ATU) with reinforced concrete (C.ATU) and HDPE (H.ATU) tank; and constructed wetland (CW) with three biochar concentrations in the substrate (0%; 10, and 20% v:v), dubbed CW.BC0, CW.BC10 and CW.BC20, respectively. CML 2001 in SimaPro® was used to evaluate the impacts of the treatment of 1 m3 wastewater. The OWTS were compared on their overall environmental performance scores (OEP). ATUs have higher impacts on human toxicity, eutrophication, freshwater and marine ecotoxicity. The CW.BC20 has the lowest global warming impact (GWP) while CW.BC0 has the highest. Electricity consumption was the largest contributor to the impacts of the ATUs. PVC pipes, coir peat, geomembrane, and electronic devices were the biggest contributors to the impacts of the CWs. The OEP of the CWs were almost a third of the ATUs’ (6.07E-03). Changes in electricity sources were tested according to the 2030-Australian targets; increasing renewables share improves the OEP of ATUs by 39%; nevertheless, CWs continue to outperform the ATUs. Variations in biochar biodegradation had a small effect on the OEP of CWs; being relevant only to GWP. This study provides a reference to policy makers for better evaluation of OWTS. HIGHLIGHTS First to present comparative LCA of constructed wetlands vs aerated treatment units for onsite domestic wastewater treatment (OWTS).; Investigates the consequences of future changes in electricity generation on the environmental efficiency of OWTS.; Investigates the effect of construction material choice on the overall environmental performance of the systems (OEP).;