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Leaching composition and associated microbial community of recycled concrete aggregate (RCA)

Lookup NU author(s): Dr Lucia Rodriguez Freire


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© 2022 Elsevier B.V. Recycled concrete aggregate (RCA) has been used as an alternative sustainable material in the construction industry, but RCA long-term environmental impacts are unknown. In this study, the bacterial enrichment potential to reduce the alkalinity of two different types of RCA was examined, from laboratory-produced concrete and from a stockpile of demolished concrete that had been in service in transportation applications. Washed and un-washed lab and field RCA were biostimulated by being exposed to ATCC® Medium 661 in batch experiments. pH, metal composition and microbial community changes in the leachates were monitored over time. Results show that initial pH of field RCA leachate could be decreased to less concerning values, as low as 8, but concentrations of some metals in the leachate exceeded groundwater quality standards. However, the biostimulated RCA released lower metal concentration and was more resistant to pH increases than non-biostimulated RCA during a long-term leaching experiment with DI water. The microbial community was enriched on anaerobic, halotolerant and alkaliphile microorganisms, resistant to extreme environmental conditions. The outcome of this research suggests a baseline for field RCA pretreatment before field application, using a biostimulation method that would generate a less environmentally detrimental runoff.

Publication metadata

Author(s): Soleimanifar M, Jayasuriya A, Adams MP, Rodriguez-Freire L

Publication type: Article

Publication status: Published

Journal: Journal of Hazardous Materials

Year: 2023

Volume: 442

Print publication date: 15/01/2023

Online publication date: 23/09/2022

Acceptance date: 20/09/2022

ISSN (print): 0304-3894

ISSN (electronic): 1873-3336

Publisher: Elsevier BV


DOI: 10.1016/j.jhazmat.2022.130048


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