Study on hydraulic conductivity of dredged sediment-attapulgite vertical cutoff walls under confining pressure.

Landfills require effective containment systems to prevent the leakage of leachate into the underground environment. Cutoff walls are commonly employed for this purpose, with options including rigid and flexible designs. In areas where structural strength is not a primary concern, flexible cutoff walls offer lower permeability and environmental benefits due to their lack of cement content, thereby reducing CO2 emissions.

Variation and correlation between water retention capacity and gas permeability of compacted loess overburden during wetting-drying cycles.

Landfill gases can have numerous detrimental effects on the global climate and urban ecological environment. The protective efficacy of the final cover layer against landfill gases, following exposure to periodic natural meteorological changes during long-term service, remains unclear. This study conducted centrifuge tests and gas permeability tests on compacted loess.

Study on semi-dynamic leaching and microstructure characteristics of MSWI fly ash solidified sediment.

municipal solid waste incineration (MSWI) fly ash partially replaces cement to solidify sediment, and then can be used as intermediate cover materials in landfill as one of the resources utilization ways of MSWI fly ash and sediment. The strength and the semi-dynamic leaching characteristics of MSWI fly ash solidified sediment under hydrochloric acid attack at different pH were studied by means of unconfined compressive strength (UCS), semi-dynamic leaching, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA). Results revealed that the UCS strength increased as the curing age and cement content increased.

One-step processing of waste dredged slurry into planting soil by targeted pretreatment and vacuum filtration.

A novel method, targeted pretreatment and vacuum filtration (TP-VF), is introduced and validated in this study. TP-VF offers a one-step solution for efficiently dewatering dredged slurry (DS) characterized by heavy metal contamination, high salinity, and excessive moisture content. This innovative approach combines targeted pretreatment (TP) and vacuum filtration (VF) to transform DS into the viable planting soil.

New insight into the additives in preparation and reduction of shield slurry.

In the preparation of the slurry in the slurry shield (SSS) and subsequent reduction of the waste slurry produced by the slurry shield (WSSS), the additives in SSS improve the quality of filtration cake on the excavation surface, but they may also remain in WSSS, which have a negative impact on the reduction efficiency of WSSS. Therefore, it is valuable to establish the relationship between SSS and WSSS with additives as a link. Given this, this paper prepared WSSS with different dosages of additives and studied the influence of residual additives on the reduction.

The permeability of dredged material-bentonite backfills.

Extensive attention has been paid to the treatment and disposal of dredged material, and there is a need to clarify the feasibility of recycling dredged material by using it as backfill in soil-bentonite vertical cutoff walls. By setting the dredged material in the Baimao storage yard of Meiliang Bay in Taihu Lake and bentonite as the research objects, this paper studied the influences of bentonite content, confining pressure and pore size distribution on the permeability of dredged material-bentonite backfills. According to the test results, from the perspective of medium-term and short-term permeability, it is feasible to recycle dredged material by using it as backfill in a vertical cutoff wall.

Studies on the chemical compatibility of soil-bentonite cut-off walls for landfills.

Leachate contains composite contaminants, and the chemical compatibility of soil-bentonite cut-off walls is unclear. To better understand the issue, Fujian standard sand is used to represent a sandy soil stratum. Two clays were used as additive to examine the chemical compatibility of the soil-bentonite model backfills under the condition of composite contaminants.