Evaluation of dual permeability of gas flow in municipal solid waste: Experiment and modeling

et al. 2017

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Permeability is a very important parameter to evaluate the landfill gas (LFG) transport properties of municipal solid waste (MSW). Waste permeability is largely dependent on pore structure, which is affected directly by compression stress and degradation. In this article, laboratory tests were conducted to determine the permeability of MSW under different stresses and degradation phases. Test results showed that porosity and permeability values were in the range of 0.11–0.65 and 8.7 × 10−14–7.29 × 10−12 m2, respectively. The porosity of waste samples declined exponentially with the increase of compacted density and linearly with the increase in water content. Permeability decreased significantly with stress and degradation because of the increase in compacted density and finer particles of the waste, which led to low porosity of the samples. The influence of stress on permeability was in the scope of 1.6 × 10−12–3.7 × 10−12 m2, whereas porosity was 0.23–0.34. However, the effect of coupled stress and degradation on permeability was reduced to more than an order of magnitude. The power model was found to be suitable for fresh and degradation wastes, whereas Kozeny–Carman model was only suitable for old wastes. This study provides theoretical and practical significance for environmental pollution control and resource utilization of LFG in landfills. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1694–1699, 2017

Section: Effects Of Degradation On Permeability and Porositymentioning

confidence: 63%

“…Sample size was artificially broken to less than 4 cm. The anaerobic degradation operation was similar to that conducted by Liu et al [21]. Samples n1 to n3 discussed the influence of stress on the density and porosity of the samples.…”

Section: Methodsmentioning

confidence: 92%

Experimental study of the porosity and permeability of municipal solid waste

Zeng

et al. 2017

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“…On the other hand, preferential flow was apparent because of the obvious heterogeneities of the pore structure in the landfill body . However, the simplified SPM could not describe the process of gas preferential flow . In the present study, the effect of moisture content and biodegradation on preferential permeation was further analyzed through a gas pressure dropping test.…”

Section: Introductionmentioning

confidence: 89%

Evaluation of dual permeability of gas flow in municipal solid waste: Extraction well operation

et al. 2016

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The dual permeability model (DPM) is used to describe the gas flow in landfills under the preferential flow effect. A steady‐state radial DPM was developed in this study to predict gas distribution at extraction well operations. Two typical cases of a short‐term pumping field test from a single extraction well were also studied. The sensitivity of kf/km and mass transfer coefficient in the DPM was simulated. The mechanism of higher deviation between the simulation result and the test could be explained by the gas flux and influence radius, as determined by the single permeability model based on gas pressure distribution in the radial direction. The reliability of the DPM in the prediction of gas flux and influence radius in extraction wells was initially verified. The study provides evidence of the improvement of the design and operation parameters of extraction wells in landfills using the proposed method. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1381–1386, 2016

“…Liu et al . (2016a,b) conducted an aeration test in a field site in the Yiling Landfill in China. The average injection rate of a single well in the initial phase was 82 m 3 /h.…”

Section: Operation Parameters Of Air Injection Wellmentioning

confidence: 99%

“…Liu et al . (2016a) preliminary testified the gas preferential flow in waste body based on the gas pressure dropping test and dual‐permeability model . Test result showed that the space of the matrix domain was vastly larger than the fracture domain.…”

Section: Issue and Proposalmentioning

confidence: 99%

The viability of design and operation of the air injection well for improvement In Situ repair capacity in landfill

et al. 2016

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The rationality of air injection well for operation parameter design is important for effective repair and safety of aeration systems in landfills. On the basis of the literature, the operating results of the air injection systems used in field sites were summarized, and the key design parameters were addressed. The operation and assessment of aeration systems were presented. First, the behavior of oxygen transport was caused by the characteristics of the pore media in the waste body. A mathematical model was needed to address the spatial–temporal evolutions of oxygen concentration in landfill. The optimum design method of gas injection well should be developed to elevate the oxygen content at maximum level across the field site, applying to most landfills. Second, an effective leachate exchange and recirculation plan should be developed to ensure sustained aerobic reaction in full scale. Some experiences of leachate discharge in field sites were presented. Third, the relationship between oxygen consumption and stability indicators should be determined to create an effective aeration plan. This function will help evaluate the reliability of aeration systems. This study provides evidence for the design, construction, operation, and effectiveness assessment of air injection well in repair engineering of landfills. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 412–419, 2017