LCA of Disposal Practices for Arsenic-Bearing Iron Oxides Reveals the Need for Advanced Arsenic Recovery

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Iron (Fe)-based groundwater treatment removes carcinogenic arsenic (As) effectively but generates toxic As-rich Fe oxide water treatment residuals (As WTRs) that must be managed appropriately to prevent environmental contamination. In this study, we apply life cycle assessment (LCA) to compare the toxicity impacts of four common As WTR disposal strategies that have different infrastructure requirements and waste control: (i) landfilling, (ii) brick stabilization, (iii) mixture with organic waste, and (iv) open disposal. The As disposal toxicity impacts (functional unit = 1.0 kg As) are compared and benchmarked against impacts of current methods to produce marketable As compounds via As mining and concentrate processing. Landfilling had the lowest non-carcinogen toxicity (2.0 × 10-3 CTUh), carcinogen toxicity (3.8 × 10-5 CTUh), and ecotoxicity (4.6 × 103 CTUe) impacts of the four disposal strategies, with the largest toxicity source being As emission via sewer discharge of treated landfill leachate. Although landfilling had the lowest toxicity impacts, the stored toxicity of this strategy was substantial (ratio of stored toxicity/emitted As = 13), suggesting that landfill disposal simply converts direct As emissions to an impending As toxicity problem for future generations. The remaining disposal strategies, which are frequently practiced in low-income rural As-affected areas, performed poorly. These strategies yielded ~3-10 times greater human toxicity and ecotoxicity impacts than landfilling. The significant drawbacks of each disposal strategy indicated by the LCA highlight the urgent need for new methods to recover As from WTRs and convert it into valuable As compounds. Such advanced As recovery technologies, which have not been documented previously, would decrease the stored As toxicity and As emissions from both WTR disposal and from mining As ore.

TidsskriftEnvironmental Science and Technology
Udgave nummer19
Sider (fra-til)14109–14119
Antal sider11
StatusUdgivet - 2022

Bibliografisk note

Funding Information:
We gratefully acknowledge Daniel Renneisen, Danielle Pietro, Sofie Henriksen, and the Lawrence Berkeley National Laboratory (LBNL) TEA-LCA working group for useful discussions and technical guidance throughout the various stages of this work. The first and third author acknowledge funding support from a Geocenter Danmark start-up grant. The first author also acknowledges funding from a Project1 grant (case no 1127-00207B) from the Independent Research Fund Denmark (IRFD). The authors gratefully acknowledge support from the U.S. Department of Energy under contract no. DE-AC02-05CH11231 with the LBNL.

Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.

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