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Carrollton, TX, United States

Hossain M.S.,University of Texas at Arlington | Haque M.A.,Bryant Consultants Inc. | Hoyos L.R.,University of Texas at Arlington
Geotechnical and Geological Engineering | Year: 2010

Bioreactor landfills are operated to enhance refuse decomposition, gas production, and waste stabilization. The major aspect of bioreactor landfill operation is the recirculation of collected leachate back through the refuse mass. Due to the presence of additional leachate and accelerated decomposition, the characteristics of Municipal Solid Waste (MSW) in bioreactor landfills are expected to change. About 50% of the continental United States comes under the designated seismic impact zone. The federal regulations have focused increase attention on seismic design of solid waste fills, and have mandated that the solid waste landfills located in the seismic impact zones should be designed to resist the earthquake. Accordingly, assessment of dynamic properties of landfills is one of the major geotechnical tasks in landfill engineering. In order to understand the changes in dynamic properties of bioreactor waste mass with time and decomposition, four small scale bioreactor landfills were simulated in laboratory and samples were prepared to represent each phase of decomposition. The state of decomposition was quantified by methane yield, pH, and volatile organic content (VOC). A number of Resonant Column (RC) tests were performed to evaluate the dynamic properties (stiffness and damping) of MSW. The test results indicated that the normalized shear modulus reduction and damping curves are significantly affected by the degree of decomposition. The shear modulus increased from 2.11 MPa in Phase I to 12.56 MPa in Phase IV. The increase was attributed to the breakdown of fibrous nature of solid waste particles as it degrades. Therefore, considering MSW properties to be uniform throughout the bioreactor landfill is not a reasonable assumption and the shear modulus reduction curves should be evaluated based on the degree of MSW decomposition, rather than the sample composition itself. © 2010 Springer Science+Business Media B.V.

Hossain M.S.,University of Texas at Arlington | Haque M.A.,Bryant Consultants Inc.
Journal of Materials in Civil Engineering | Year: 2012

To estimate the generated leachate and design of a leachate recirculation system, a clear understanding of the hydraulic conductivity of municipal solid waste with degradation, and the effects of intermixed cover soils, is necessary. Two sets of laboratory-scale bioreactor landfills were simulated and sampled at various phases of decomposition. The state of decomposition was quantified by methane yield, pH,and volatile organic content. The matrix structure of the degradablesolid waste component was broken down because of decomposition. However, daily cover soil, a nondegradable constituent of municipal solid waste, remained constant. Therefore, interaction between daily cover soil and municipal solid waste particles are expected to affect hydraulic characteristics resulting from degradation. The current study shows that the hydraulic conductivity of municipal solid waste with cover soil is lower than that without any intermixed cover soils. Based on experimental results, hydraulic conductivity of municipal solid waste samples in (aerobic) phase I is 5.8 × 10-3 cm/s, and drops to 2.6 × 10-3 and 1.7 × 10-3 cm/s, with 20 and 30% cover soils, respectively. Hydraulic conductivity decreases with increasing soil percentage. Therefore, the effects of cover soils on municipal solid waste hydraulic conductivity should be evaluated and taken into consideration during the design and operation of a landfill recirculation system. © 2012 American Society of Civil Engineers.

Bryant Consultants Inc. | Date: 2008-01-22

Computer software and computer hardware for subsurface geological mapping.

A system and method is provided for on-site site risk assessment and to encourage collaboration between professional disciplines related to land development and construction projects. A graphical risk analysis system is provided based on answers to interdisciplinary questions related to risks. Use of the system promotes a complete checklist of interdisciplinary and informational consultation which, when completed for a project, assesses the risk related to construction site development and allows for reduction in risk as the project progresses.

Bryant Consultants Inc. | Date: 2011-03-01

Subsurface geological detection equipment, namely, computer controlled resistance meters.

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