Sewage sludge ash-incorporated stabilisation/solidification for recycling and remediation of marine sediments. (1st January 2022)

• Record Type: Journal Article
• Authors: Zhou, Yifan; Cai, Guanghua; Cheeseman, Chris; Li, Jiangshan; Poon, Chi Sun
• Is Part Of: Journal of environmental management. Volume 301(2022)
• Publication Date: 2022-01-01
• Subjects: Stabilisation/solidification -- Sediments -- Sewage sludge ash -- Pore structure -- Heavy metals leaching -- Waste recycling; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2021.113877
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Finding suitable disposal sites for dredged marine sediments and incinerated sewage sludge ash (ISSA) is a challenge. Stabilisation/solidification (S/S) has become an increasingly popular remediation technology. This study sheds light on the possible beneficial use of ISSA together with traditional binders to stabilise/solidify marine sediments. The performance of the binders on S/S of sediment 1 (clean) and sediment 2 (contaminated) was also compared. The results showed that the use of ISSA as part of the binder was effective in promoting the strength of the sediment with a high initial moisture content due to ISSA porous and high water absorption characteristics. The sediments treated with 10% cement and 20% ISSA attained the highest strength. Also, cement hydration as well as pozzolanic reactions between ISSA and Ca(OH)2 made contributions to the strength development. This was supported by the microstructural analysis, in particular the porosity results. In terms of environmental impacts, two leaching tests (toxicity characteristic leaching procedure and synthetic precipitation leaching procedure) found that all the S/S treated sediment by 10% lime and 20% ISSA resulted in the lowest leachate concentrations under the on-site reuse scenario or under simulative acidic rainfall conditions. Therefore, recycling waste ISSA with lime can be used as an appealing binder to replace cement to stabilise/solidify dredged marine sediments for producing fill materials. Graphical abstract: Image 1 Highlights: Remediation of marine sediments with waste sludge ash facilitates recycling. Sludge ash is more suitable for treating sediments with high water content. Compressive strength is inversely correlated with average pore diameter. Lime-sludge ash improved strength of sediments for on-site filling application. Heavy metals leaching is within the regulatory limits and safe for reuse.