Hybrid life cycle assessment (hLCA)-combining conventional process-based LCA and environmentally extended input–output analysis (EEIOA) in a variety of ways-has been developed for almost 40 years (Crawford et al. Although the data are Australian specific, the underlying procedure is applicable to any country as long as suitable data are available. On average, process-based CFIs are 21–32% lower than the corresponding hybrid CFIs, which is larger than the uncertainties resulting from either price variation, EEIO data uncertainty or scenarios on how the hybridization is conducted. Major inputs from the IO system are identified, and the sensitivity and uncertainty of hybrid results against unit price variations and EEIO table uncertainties are quantified via Monte Carlo simulations. How different assumptions and settings on the hybridization influence the difference between process-based and hybrid results is further investigated and discussed intensively. A hybridized AusLCI database is generated and used to calculate the hybrid carbon footprint intensities (CFIs) of all AusLCI processes. Data from the Australian Life Cycle Inventory Database (AusLCI) and the Australian Industrial Ecology Virtual Laboratory are used to demonstrate this routine. This study endeavors to expand the accessibility of hybrid LCA from specialists to practitioners by developing a streamlined and semi-automated hybrid LCA data compilation routine in an input–output virtual laboratory. This manuscript version is made available under the CC-BY-NC-ND 4.Hybrid life cycle assessment (LCA) has been developed for almost 40 years, but its applications are still limited to certain products/industries. OpenLCA Environmental impacts Active treatments Acid dosing Reedbeds Passive treatments Journal of cleaner production, 202, 401-412. Options for managing alkaline steel slag leachate: A life cycle assessment.
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Potential design measures to enhance environmental performance of the treatments regarding metal removal and recovery are discussed and could inform operational management at active and legacy steel slag disposal sites. Both passive treatment options had better environmental performance than the active treatment options. Higher uncertainty was associated with the categories particulate matter formation, climate change and human toxicity, as they are driven by indirect emissions from electricity and chemicals production. The major contributor to these impact categories was the Solvay process to produce CaCl2.
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For climate change, the lowest impact was calculated for P-G < P-P < A-H2SO4 < A-CO2 < A-CaCl2, while for particulate matter/respiratory inorganics, the options ranked as follows P-G < P-P < A-CO2 < A-H2SO4 < A-CaCl2. Regarding human toxicity, A-CaCl2 impact was 1260 times higher than the lowest impact option (A-CO2) for carcinogenics and 53 times higher for non-carcinogenics (A-H2SO4). The A-CaCl2 option scored worse than all other treatments for all considered environmental impact categories. The environmental impacts were calculated in OpenLCA using the ELCD database and ILCD 2011 method, covering twelve impact categories. Inventory data were obtained from project designers, commercial suppliers, laboratory data and field tests.
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The functional unit was 1 m3 of treated leachate with pH < 9, considering 24 h and 365 days of operating, maintenance operations every year, and service life of 20 years. Five options were compared: active treatment by acid dosing (A-H2SO4), active treatment by carbon dioxide dosing (A-CO2), active treatment by calcium chloride dosing (A-CaCl2), passive treatment by cascade and reedbeds with pumping (P-P), and passive treatment by cascade and reedbeds in a gravity-driven configuration (P-G).
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This study aims to compare different treatment options for steel slag leachate through a life cycle assessment (LCA). Management of steel slag (a major by-product of the steel industry) includes the treatment of highly alkaline leachate (pH > 11.5) from rainwater infiltration of slag deposits to prevent adverse impact upon surface or ground waters.