Physico-mechanical and microstructural behaviour of high-water content zinc-contaminated dredged sediment treated with integrated approach PHDVPSS

Aamir Khan Mastoi; Hefu Pu; Xunlong Chen; Alidekyi Sharif Nyanzi; Ashfaque Ahmed Jhatial

doi:10.1007/s11356-021-14770-0

Physico-mechanical and microstructural behaviour of high-water content zinc-contaminated dredged sediment treated with integrated approach PHDVPSS

Environ Sci Pollut Res Int. 2021 Nov;28(41):58331-58341. doi: 10.1007/s11356-021-14770-0. Epub 2021 Jun 11.

Authors

Aamir Khan Mastoi^{1

2}, Hefu Pu³, Xunlong Chen⁴, Alidekyi Sharif Nyanzi³, Ashfaque Ahmed Jhatial⁵

Affiliations

¹ Institute of Geotechnical and Underground Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China. aamirkhan@quest.edu.pk.
² Department of Civil Engineering, Quaid-e-Awam University of Engineering, Science and Technology, Nawabshah, Sindh, 67450, Pakistan. aamirkhan@quest.edu.pk.
³ Institute of Geotechnical and Underground Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
⁴ Institute of Geotechnical and Underground Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China. chenxl5218@foxmail.com.
⁵ Department of Civil Engineering, Mehran University of Engineering and Technology, Shaheed Zulfiqar Ali Bhutto Campus, Khairpur Mirs, Sindh, Pakistan.

PMID: 34115301
DOI: 10.1007/s11356-021-14770-0

Abstract

This paper uses a new integrated method, namely PHDVPSS, which utilizes vacuum pressure (VP) coupled with prefabricated horizontal drain along with solidification/stabilization (SS) for the effective treatment of high-water content dredged contaminated sediment (DCS). This study sought to evaluate the physico-mechanical and microstructural behaviour of high-water content DCS treated with MgO-GGBS (MG) and Portland cement (PC) as PHDVPSS binders and compared to the traditional Portland cement solidification/stabilization (SS-PC) method. Physico-mechanical and microstructural characteristics of the DCS treated with the PHDVPSS method were evaluated by performing a number of tests such as unconfined compressive strength (UCS), toxicity characteristics of the leaching process (TCLP), pH, X-ray diffraction (XRD) and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS). Treatment results showed that the DCS treated with the MG binder in the PHDVPSS method showed superior performance in terms of a significant reduction in the water content and leachability of zinc (Zn) along with higher mechanical strength and dry density of the samples compared to the traditional SS-PC method. After 56-day curing time, VP-MG cases showed 17.6 % and 50 % higher dry density values, resulting in 2.5 and 17.3 times higher UCS values than VP-PC and SS-PC cases, respectively. In contrast, VP-MG cases showed lower pH values than those of VP-PC and SS-PC cases. Moreover, VP-MG cases exhibited 37.5 % and 44.3 % lower leached Zn concentration during a TCLP test than VP-PC cases and SS-PC cases, respectively. XRD and SEM-EDS tests showed that more voluminous hydration products were produced in the VP-MG cases, which in turn produced a dense stabilized matrix and significantly reduced the leachability of zinc.

Keywords: Dredged contaminated sediments; Heavy metal; Solidification/stabilization; Vacuum dewatering; Zinc leaching.

MeSH terms

Construction Materials
Metals, Heavy* / analysis
Soil
Soil Pollutants* / analysis
Water
Zinc

Substances

Metals, Heavy
Soil
Soil Pollutants
Water
Zinc

Grants and funding

Grant No. 2016YFC0800200/National Key Research and Development Program of China