Assessment of municipal solid waste settlement models based on field-scale data analysis

Abstract

ASSESSMENT OF MUNICIPAL SOLID WASTE SETTLEMENT MODELS BASED ON FIELD-SCALE DATA ANALYSISAn evaluation of municipal solid waste (MSW) settlement model performance and applicability was conducted based on analysis of two field-scale datasets: (1) Yolo and (2) Deer Track Bioreactor Experiment (DTBE). Yolo data were used to assess a multi-layer immediate settlement analysis and model applicability to represent compression behavior in conventional and bioreactor landfills. The DTBE included four waste layers constituting a composite waste thickness. Settlement data for each waste layer were simulated to assess variation in model parameters, and a composite waste settlement prediction was completed via applying average DTBE model parameters to each waste layer and summing settlement to represent measured settlement at the top of the waste column.The multi-layer immediate settlement analysis developed for Yolo provides a framework to estimate the initial waste thickness and waste thickness at end-of-immediate compression.An empirical estimate of the immediate compression ratio (C c ' = 0.23) combined with precompression stress (10 to 15 kPa) and recompression ratio = 1/10•C c ' yielded the target immediate settlement for the Yolo test cells. A precompression stress and recompression ratio may need to be included when using empirical estimates of C c ' to predict immediate settlement under small vertical stress (e.g., less than 15 kPa). shown to provide accurate simulations and predictions of field-scale datasets.The Gourc model included the lowest number of total and optimized model parameters and yielded high statistical performance for the DTBE prediction (R 2 = 0.99). The Gourc model was also found to be the most applicable and straightforward to implement and is recommended for use in practice. All other models that included unique functions for immediate compression, mechanical creep, and biocompression (Machado, Sowers, Marques, Babu, and Chen-2012) are capable of yielding satisfactory MSW simulations and predictions; however, additional model and/or model constraints are necessary for implementing these models.iv ACKNOWLEDGEMENTS

Modelling the Mechanical Behaviour of Municipal Solid Waste for an Engineered Landfill Using Viscoelasticity and Other Established Concepts

“…The Yolo site dataset included results from both a control cell and a cell with a leachate recirculation system to enhance waste stabilization. Bareither and Kwak (2015) found that the models proposed by Gourc et al (2010) and Marques et a. (2003) provided the best fit in terms of the coefficient of determination.…”

“…The best fit parameters from only the first year of data performed very poorly at predicting the 6 year settlement for all three models, with each model grossly underestimating the final settlement. Bareither and Kwak (2015) similarly compared several previously proposed models to new settlement datasets. They used Gibson and Lo (1961), Marques et al (2003), Hossain and Gabr (2005) (2010) and Chen et al (2012).…”

“…All models provided a good fit when parameters were fit for each layer, however, some models featured fitting parameters that varied from lift to lift. Bareither and Kwak (2015) determined that the model proposed by Gourc et al (2010) provided the best fit, due to its lower number of optimized parameters, high statistical fit for the overall settlement data from the top of the waste profile, and because its model parameters were more physically based. Van Geel and Murray (2015) developed a three-component model based on Marques et al (2003) Marques et al (2003) and from their own study provided a better estimate of settlement for typical field scenarios.…”

Model for degradation-induced settlements as part of a coupled landfill model

“…Thus, the experiments confirm the phenomenon of degradation‐induced settlements. A recent study on the comparison of settlement models with measured field data is presented by Bareither and Kwak . The inclusion of degradation‐induced settlements is found to be of importance for description of long‐term settlements.…”

Experimental Study on Compression and Intrinsic Permeability Characteristics of Municipal Solid Waste

“…Deformation and settlement of MSW is one of the main environmental geotechnical engineering problems involved in the landfill [9]. It can provide scientific basis for prediction of landfill volume, increase of storage capacity, cracking failure of the closure cover system, design and maintenance of the gas-liquid drainage system, and site reuse by landfill settlement research [10]. Compressive deformation characteristics of MSW are of great significance for analysis of landfill settlement [11,12].…”