Stabilization of carbon through co-addition of water treatment residuals with anaerobic digested sludge in a coarse textured soil

Lukashe, Noxolo S.; Stone, Wendy; Pereira, Ryan; Trojahn, Sara; Hardie, Ailsa G.; Johnson, Karen L.; Clarke, Catherine E.

Abstract

Coarse textured soils have low potential to store carbon (C) due to lack of mineral oxides and have low clay content to protect C from biodegradation and leaching. This study evaluated the potential of stabilizing C by adding metal oxyhydroxide-rich water treatment residuals (WTRs) to an aeolian pure sand (<5% clay) topsoil amended with anaerobic digestate (AD) sludge. The AD sludge was applied at 5% (w/w) with aluminum based WTR (Al-WTR) and iron based WTR (Fe-WTR) co-applied at 1:1 and 2:1 WTR:AD (w/w) ratios and incubated at room temperature for 132 days. The cumulative mineralized C was normalized to the total organic C of the treatments. Co-addition with Al-WTR showed to be more effective in stabilizing C through decreased cumulative mineralized C by 48% and 57% in 1Al-WTR:1AD and 2Al-WTR:1AD, respectively, compared to AD sludge sole amendment. Co-application with Al-WTR also decreased permanganate oxidizable C by 37% and dissolved organic C by 51%. Co-application with Fe-WTR did not decrease the concentration of these labile C pools to the same extent, possibly due to the selective use of Fe-WTRs to treat organic-rich raw water. This makes it less effective in stabilizing C in a pure sand relative to Al-WTR due to chemical instability of the Fe-organic complexes. The Al-WTR provides a promising co-amendment to increase C sequestration in pure sands when co-applied with biosolids. The co-amendment approach will not only facilitate C sequestration but also contributes to waste management, aligning to the objectives of a circular economy.

Citation

Lukashe, N. S., Stone, W., Pereira, R., Trojahn, S., Hardie, A. G., Johnson, K. L., & Clarke, C. E. (2024). Stabilization of carbon through co-addition of water treatment residuals with anaerobic digested sludge in a coarse textured soil. Journal of Environmental Management, 366, Article 121904. https://doi.org/10.1016/j.jenvman.2024.121904

• Journal Article Type: Article
• Acceptance Date: Jul 14, 2024
• Online Publication Date: Jul 18, 2024
• Publication Date: 2024-08
• Deposit Date: Jul 31, 2024
• Publicly Available Date: Jul 31, 2024
• Journal: Journal of Environmental Management
• Print ISSN: 0301-4797
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 366
• Article Number: 121904
• DOI: https://doi.org/10.1016/j.jenvman.2024.121904
• Public URL: https://durham-repository.worktribe.com/output/2614827