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Temporal and spatial pore water pressure distribution surrounding a vertical landfill leachate recirculation well.

Kadambala R, Townsend TG, Jain P, Singh K - Int J Environ Res Public Health (2011)

Bottom Line: While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported.After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time.The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Engineering Sciences, University of Florida, PO BOX 116450, Gainesville, FL 32611, USA. kadambalar@cdm.com

ABSTRACT
Addition of liquids into landfilled waste can result in an increase in pore water pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured pore pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth.

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Variation the pore pressures in the waste surrounding Well 2 as a function of depth on day 93 while the leachate was actively added to the well. Error bars indicate one standard deviation of uncertainty. (a) A radial distance of 2.15 m from the buried vertical well; (b) A radial distance of 3 m from the buried vertical well; (c) A radial distance of 6.3 m from the buried vertical well; (d) A radial distance of 7.8 m from the buried vertical well.
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f8-ijerph-08-01692: Variation the pore pressures in the waste surrounding Well 2 as a function of depth on day 93 while the leachate was actively added to the well. Error bars indicate one standard deviation of uncertainty. (a) A radial distance of 2.15 m from the buried vertical well; (b) A radial distance of 3 m from the buried vertical well; (c) A radial distance of 6.3 m from the buried vertical well; (d) A radial distance of 7.8 m from the buried vertical well.

Mentions: Figure 7 and Figure 8 present the results of spatial variation of pore pressure in the waste surrounding the leachate recirculation well (Well 2) on day 93, while leachate was actively injected at a pressure of 20 m of w.c. (at the bottom of the well) and at a flow rate of 6 × 10−4 m3/s. A cumulative volume of 1,400 m3 of leachate had been recirculated up to this point of time. As shown in Figure 2, the piezometer wells extended deeper than the leachate recirculation well. Since the pressure at the recirculation well location at a depth corresponding to the bottom of the piezometer well could not be measured, the pressure at the well location for this depth is not presented in Figure 7d.


Temporal and spatial pore water pressure distribution surrounding a vertical landfill leachate recirculation well.

Kadambala R, Townsend TG, Jain P, Singh K - Int J Environ Res Public Health (2011)

Variation the pore pressures in the waste surrounding Well 2 as a function of depth on day 93 while the leachate was actively added to the well. Error bars indicate one standard deviation of uncertainty. (a) A radial distance of 2.15 m from the buried vertical well; (b) A radial distance of 3 m from the buried vertical well; (c) A radial distance of 6.3 m from the buried vertical well; (d) A radial distance of 7.8 m from the buried vertical well.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3108135&req=5

f8-ijerph-08-01692: Variation the pore pressures in the waste surrounding Well 2 as a function of depth on day 93 while the leachate was actively added to the well. Error bars indicate one standard deviation of uncertainty. (a) A radial distance of 2.15 m from the buried vertical well; (b) A radial distance of 3 m from the buried vertical well; (c) A radial distance of 6.3 m from the buried vertical well; (d) A radial distance of 7.8 m from the buried vertical well.
Mentions: Figure 7 and Figure 8 present the results of spatial variation of pore pressure in the waste surrounding the leachate recirculation well (Well 2) on day 93, while leachate was actively injected at a pressure of 20 m of w.c. (at the bottom of the well) and at a flow rate of 6 × 10−4 m3/s. A cumulative volume of 1,400 m3 of leachate had been recirculated up to this point of time. As shown in Figure 2, the piezometer wells extended deeper than the leachate recirculation well. Since the pressure at the recirculation well location at a depth corresponding to the bottom of the piezometer well could not be measured, the pressure at the well location for this depth is not presented in Figure 7d.

Bottom Line: While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported.After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time.The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Engineering Sciences, University of Florida, PO BOX 116450, Gainesville, FL 32611, USA. kadambalar@cdm.com

ABSTRACT
Addition of liquids into landfilled waste can result in an increase in pore water pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured pore pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth.

Show MeSH