Evaluating gas breakthrough pressure and gas permeability in a landfill cover layer for mitigation of hazardous gas emissions

Wen, Shaojie; Cheng, Wen-Chieh; Li, Dongfeng; Hu, Wenle

doi:10.1016/j.jenvman.2023.117617

Cited by 23 publications

(4 citation statements)

References 44 publications

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“…Although it can measure the volume change of soil samples using a flexible wall cell and apply confining pressure, it still does not solve the problem of gas pressure fluctuation (15 kPa) [30][31][32][33][34]. Compared with the flexible wall permeameter, although the triaxial permeameter does not solve the problem of gas pressure fluctuation (3.2 kPa), it is widely used due to its high testing accuracy and the ability to apply confining pressure and principal pressure [35][36][37][38][39]. By developing a gas supply device with two Mariotte bottles [40] as the core component, Chen et al (2021) effectively addressed the gas pressure fluctuation under low pressures (20 kPa), simplified the measurement of gas flow velocity, and improved the gas pressure supply accuracy to 0.01 kPa [24].…”

Section: Introductionmentioning

confidence: 99%

A Temperature-Controlled Apparatus for Gas Permeability under Low Gas Pressure

Wu,

Huang,

Liu

et al. 2023

Applied Sciences

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The measurement of soil gas permeability is influenced by the temperature and pressure fluctuation in the low gas pressure region. In order to investigate these influences, a soil temperature-controlled apparatus connected to a low-gas-pressure supply equipment is proposed in this study. The low constant gas pressure is supplied by two Mariotte bottles, by which the airflow rate is measured. Meanwhile, the soil specimen is controlled by a temperature-controlled apparatus. During the test, the negative pore water pressure and volume change of the soil specimen are measured. Through the temperature-controlled apparatus, it is observed that as the temperature increases from 25 °C to 60 °C, there is a corresponding increase in soil sample porosity by 5.4%, while the negative pressure of pore water decreases by 11.1%. This can be attributed to the reduction in the surface tension of contractile skin caused by elevated temperatures. Furthermore, due to variations in gas viscosity with temperature, there was a significant decrease in the gas flow rate by 50.5%. And, the relationship between permeability and volumetric gas content at different temperatures in low-pressure regions well confirms the existing power-law model. In addition, the existence of a temperature-independent critical negative pore water pressure is observed, beyond which the intrinsic permeability remains constant. At 36 kPa of negative pore water pressure, the intrinsic permeability at 60 °C exhibits an 81.8% reduction compared to that at 25 °C. This decline in intrinsic permeability can be attributed to a diminished pore connectivity, resulting from elevated temperatures.

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Section: Introductionmentioning

confidence: 99%

A Temperature-Controlled Apparatus for Gas Permeability under Low Gas Pressure

Wu,

Huang,

Liu

et al. 2023

Applied Sciences

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“…Metallurgical processes, smelting activities, and inappropriate irrigation can discharge heavy metals into surrounding environments, and their accumulation can badly cause damage to the liver and kidney function of human body ( Chen et al, 2022 ; Bai et al, 2021a ; Chen et al, 2023 ; Bai et al, 2021b ; Wen et al, 2023 ). Lead (Pb) and copper (Cu) are considered two often-seen contaminants because of their non-biodegradability and bioaccumulation ( Bai et al, 2022b ; Bai et al, 2022c ; Xue et al, 2023 ; Xue et al, 2021 ; Xie et al, 2023 ; Wang et al, 2022c ).…”

Section: Introductionmentioning

confidence: 99%

Immobilizing lead and copper in aqueous solution using microbial- and enzyme-induced carbonate precipitation

Wang

Cheng

Xue

et al. 2023

Front. Bioeng. Biotechnol.

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Inappropriate irrigation could trigger migration of heavy metals into surrounding environments, causing their accumulation and a serious threat to human central nervous system. Traditional site remediation technologies are criticized because they are time-consuming and featured with high risk of secondary pollution. In the past few years, the microbial-induced carbonate precipitation (MICP) is considered as an alternative to traditional technologies due to its easy maneuverability. The enzyme-induced carbonate precipitate (EICP) has attracted attention because bacterial cultivation is not required prior to catalyzing urea hydrolysis. This study compared the performance of lead (Pb) and copper (Cu) remediation using MICP and EICP respectively. The effect of the degree of urea hydrolysis, mass and species of carbonate precipitation, and chemical and thermodynamic properties of carbonates on the remediation efficiency was investigated. Results indicated that ammonium ion (NH4+) concentration reduced with the increase in lead ion (Pb2+) or copper ion (Cu2+) concentration, and for a given Pb2+ or Cu2+ concentration, it was much higher under MICP than EICP. Further, the remediation efficiency against Cu2+ is approximately zero, which is way below that against Pb2+ (approximately 100%). The Cu2+ toxicity denatured and even inactivated the urease, reducing the degree of urea hydrolysis and the remediation efficiency. Moreover, the reduction in the remediation efficiency against Pb2+ and Cu2+ appeared to be due to the precipitations of cotunnite and atacamite respectively. Their chemical and thermodynamic properties were not as good as calcite, cerussite, phosgenite, and malachite. The findings shed light on the underlying mechanism affecting the remediation efficiency against Pb2+ and Cu2+.

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“…Currently, most attention is directed towards the rupture of pressurized pipelines. Some studies suggest that ground subsidence originates from the erosive action of highpressure jets on the soil, creating liquefaction phenomena in the surrounding soil layers due to high-pressure fluid scouring [7][8][9]. However, researchers have also highlighted the complexity of the interaction between pipelines and soil, owing to changes in the geometry of unconfined flow regimes, piping, and hydraulic fracturing [10].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Ground Subsidence Factors Resulting from Unpressurized Pipeline Rupture Below the Water Table

Cui,

Liu,

Geng

et al. 2023

Applied Sciences

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The rupture of an unpressurized pipeline below the water table can lead to the leakage of groundwater along with soil particles into the pipeline. This not only causes blockages in the pipeline but, more critically, can result in ground subsidence. Understanding the factors influencing this phenomenon is a subject of great interest. To delve into this matter, this study employs the DEM-CFD methodology to synergistically encompass particle dynamics and interactions within the flow domain. It introduces an innovative framework for simulating water and soil erosion subsequent to the rupture of subaqueous unpressurized pipelines. This pioneering approach introduces a novel modeling and simulation paradigm catering to the analysis of intricate phenomena of this nature. Upon validating the flow field, our investigation specifically focused on three key factors: particle friction coefficient, groundwater level, and particle size distribution. We conducted a thorough examination of the process and mechanism of water and soil loss at the pipeline leakage point and the subsequent development of stratum subsidence. Our results indicate that particles with a friction coefficient of 0.6 had a reduced maximum displacement by 8.9%, compared to particles with a friction coefficient of 0.3. Similarly, a groundwater depth of 2 m resulted in a 29.6% decrease in maximum displacement compared to a 4 m depth, with a corresponding 160.9% increase in maximum force chain strength. Discontinuous particle gradation, in contrast to continuous gradation, yielded a notable 40.3% reduction in maximum displacement and a substantial 495.1% increase in maximum force chain strength. This underscores the noteworthy influence of particle friction coefficient, groundwater table elevation, and soil particle diameter on the stability of the overlying soil strata in the vicinity of a compromised unpressurized conduit.

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Evaluating gas breakthrough pressure and gas permeability in a landfill cover layer for mitigation of hazardous gas emissions

Cited by 23 publications

References 44 publications

A Temperature-Controlled Apparatus for Gas Permeability under Low Gas Pressure

A Temperature-Controlled Apparatus for Gas Permeability under Low Gas Pressure

Immobilizing lead and copper in aqueous solution using microbial- and enzyme-induced carbonate precipitation

Numerical Simulation of Ground Subsidence Factors Resulting from Unpressurized Pipeline Rupture Below the Water Table

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