TY - JOUR
T1 - Leaching composition and associated microbial community of recycled concrete aggregate (RCA)
AU - Soleimanifar, Maedeh
AU - Jayasuriya, Anuruddha
AU - Adams, Matthew P.
AU - Rodriguez-Freire, Lucia
N1 - Funding Information: This project was supported by the start-up fund from the John A. Reif, Jr. Department of Civil and Environmental Engineering at the New Jersey Institute of Technology (NJIT). This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors are very thankful to the four anonymous reviewers for the insightful and thoughtful comments that helped improved the quality of the initial manuscript. Funding Information: This project was supported by the start-up fund from the John A. Reif, Jr. Department of Civil and Environmental Engineering at the New Jersey Institute of Technology (NJIT). This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors are very thankful to the four anonymous reviewers for the insightful and thoughtful comments that helped improved the quality of the initial manuscript. Publisher Copyright: © 2022 Elsevier B.V.
PY - 2023/1/15
Y1 - 2023/1/15
N2 - 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.
AB - 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.
KW - Alkaline leachate
KW - Biostimulation
KW - Construction materials
KW - Heavy-metal leaching
KW - Waste management
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U2 - https://doi.org/10.1016/j.jhazmat.2022.130048
DO - https://doi.org/10.1016/j.jhazmat.2022.130048
M3 - Article
C2 - 36182880
SN - 0304-3894
VL - 442
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 130048
ER -