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Abiotic and biotic compression of municipal solid waste / Christopher A. Bareither in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 8 (Août 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 8 (Août 2012) . - pp. 877–888 Titre : Abiotic and biotic compression of municipal solid waste Type de document : texte imprimé Auteurs : Christopher A. Bareither, Auteur ; Craig H. Benson, Auteur ; Tuncer B. Edil, Auteur Année de publication : 2012 Article en page(s) : pp. 877–888 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Municipal  solid  waste  Settlement  Bioreactor  landfills  Methane  generation  Leachate  Recirculation  Biocompression Résumé : This study focused on quantifying relative contributions of abiotic and biotic compression of municipal solid waste (MSW). Abiotic mechanisms include immediate compression, mechanical creep, and moisture-induced waste softening. The biotic mechanism is decomposition of the MSW organic fraction, which when coupled with mechanical creep, yields biocompression. Three 610-mm-diameter laboratory compression experiments were conducted for 1,150 days under the following conditions: (1) waste with no liquid addition (dry), (2) liquid addition spiked with biocide (abiotic), and (3) leachate recirculation (biotic). Immediate compression strain was similar in all three tests (24–27%). Mechanical creep, moisture-induced softening, and biocompression were compared via time-dependent compression ratios (C′α). Moisture-induced softening occurred in both the abiotic and biotic cells in response to liquid addition and leachate recirculation. Moisture-induced softening accelerated the accumulation of mechanical creep (i.e., approximately doubled C′α due to mechanical creep relative to the dry cell), but did not increase the overall magnitude. C′α, in the biotic cell, correlated with the methane flow rate when methanogenesis was controlled by the rate of solids hydrolysis. C′α, due to mechanical creep in the dry cell and biocompression in the biotic cell, increased exponentially with temperature, and can be represented with an exponential model. C′α, due to biocompression, was approximately one order of magnitude larger than C′α due to mechanical creep. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000660 [article] Abiotic and biotic compression of municipal solid waste [texte imprimé] / Christopher A. Bareither, Auteur ; Craig H. Benson, Auteur ; Tuncer B. Edil, Auteur . - 2012 . - pp. 877–888. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 8 (Août 2012) . - pp. 877–888 Mots-clés : Municipal  solid  waste  Settlement  Bioreactor  landfills  Methane  generation  Leachate  Recirculation  Biocompression Résumé : This study focused on quantifying relative contributions of abiotic and biotic compression of municipal solid waste (MSW). Abiotic mechanisms include immediate compression, mechanical creep, and moisture-induced waste softening. The biotic mechanism is decomposition of the MSW organic fraction, which when coupled with mechanical creep, yields biocompression. Three 610-mm-diameter laboratory compression experiments were conducted for 1,150 days under the following conditions: (1) waste with no liquid addition (dry), (2) liquid addition spiked with biocide (abiotic), and (3) leachate recirculation (biotic). Immediate compression strain was similar in all three tests (24–27%). Mechanical creep, moisture-induced softening, and biocompression were compared via time-dependent compression ratios (C′α). Moisture-induced softening occurred in both the abiotic and biotic cells in response to liquid addition and leachate recirculation. Moisture-induced softening accelerated the accumulation of mechanical creep (i.e., approximately doubled C′α due to mechanical creep relative to the dry cell), but did not increase the overall magnitude. C′α, in the biotic cell, correlated with the methane flow rate when methanogenesis was controlled by the rate of solids hydrolysis. C′α, due to mechanical creep in the dry cell and biocompression in the biotic cell, increased exponentially with temperature, and can be represented with an exponential model. C′α, due to biocompression, was approximately one order of magnitude larger than C′α due to mechanical creep. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000660

Compression behavior of municipal solid waste / Christopher A. Bareither in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1047–1062. Titre : Compression behavior of municipal solid waste : Immediate compression Type de document : texte imprimé Auteurs : Christopher A. Bareither, Auteur ; Craig H. Benson, Auteur ; Tuncer B. Edil, Auteur Année de publication : 2012 Article en page(s) : pp.1047–1062. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Solid  waste  Compression  Settlement  Landfills  Bioreactors  Sustainability Résumé : An evaluation of scale effects, stress, waste segregation, and waste decomposition on the immediate compression behavior of municipal solid waste is presented. Laboratory experiments were conducted in 64-, 100-, and 305-mm-diameter compression cells. A field-scale experiment [Deer Track Bioreactor Experiment (DTBE)] was conducted on waste of the same composition and material properties. A methodology is presented for determining the end-of-immediate compression strain (ɛEOI) that is applicable to both laboratory- and field-scale data. The compression ratio (C′c) was comparable between tests conducted in 100- and 305-mm compression cells. Compression tests in 305-mm cells conducted on six wastes (three size-differentiated fresh wastes and three decomposed wastes) yielded C′c ranging from 0.22 to 0.28 in the stress range of 25–100 kPa. A similar C′c (0.23) was determined for the DTBE (20–67 kPa). The variation in C′c is related to the waste compressibility index (WCI), which is a function of waste dry weight water content, dry unit weight, and the percent contribution of biodegradable organic waste (paper/cardboard, food waste, yard waste). A compilation of laboratory data from this study and the literature yielded a predictive relationship for the C′c and WCI. The C′c can be estimated within ±0.087 for a given WCI using this relationship. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000672 [article] Compression behavior of municipal solid waste : Immediate compression [texte imprimé] / Christopher A. Bareither, Auteur ; Craig H. Benson, Auteur ; Tuncer B. Edil, Auteur . - 2012 . - pp.1047–1062. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1047–1062. Mots-clés : Solid  waste  Compression  Settlement  Landfills  Bioreactors  Sustainability Résumé : An evaluation of scale effects, stress, waste segregation, and waste decomposition on the immediate compression behavior of municipal solid waste is presented. Laboratory experiments were conducted in 64-, 100-, and 305-mm-diameter compression cells. A field-scale experiment [Deer Track Bioreactor Experiment (DTBE)] was conducted on waste of the same composition and material properties. A methodology is presented for determining the end-of-immediate compression strain (ɛEOI) that is applicable to both laboratory- and field-scale data. The compression ratio (C′c) was comparable between tests conducted in 100- and 305-mm compression cells. Compression tests in 305-mm cells conducted on six wastes (three size-differentiated fresh wastes and three decomposed wastes) yielded C′c ranging from 0.22 to 0.28 in the stress range of 25–100 kPa. A similar C′c (0.23) was determined for the DTBE (20–67 kPa). The variation in C′c is related to the waste compressibility index (WCI), which is a function of waste dry weight water content, dry unit weight, and the percent contribution of biodegradable organic waste (paper/cardboard, food waste, yard waste). A compilation of laboratory data from this study and the literature yielded a predictive relationship for the C′c and WCI. The C′c can be estimated within ±0.087 for a given WCI using this relationship. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000672

Deer track bioreactor experiment / Christopher A. Bareither in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 6 (Juin 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 6 (Juin 2012) . - pp. 658–670 Titre : Deer track bioreactor experiment : Field-scale evaluation of municipal solid waste bioreactor performance Type de document : texte imprimé Auteurs : Christopher A. Bareither, Auteur ; Ronald J. Breitmeyer, Auteur ; Craig H. Benson, Auteur Année de publication : 2012 Article en page(s) : pp. 658–670 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Solid  waste  Landfills  Bioreactor  Decomposition  Leachate  Settlement Résumé : The Deer Track Bioreactor Experiment (DTBE) was a field-scale experiment conducted in a drainage lysimeter (8.2-m height, 2.4-m diameter) to assess the physical, chemical, and biological response of municipal solid waste with leachate addition. The experiment was operated for 1,067 days, with leachate dosing initiated on Day 399. Fresh leachate collected from a full-scale landfill was used for each dose. The ratio of cumulative leachate effluent to influent volume increased during dosing and leveled off at approximately 80%, indicating field capacity was achieved. Peak Darcy flux ranged from 2×10−7  m/s to 4×10−5  m/s, with larger flux computed for the last four doses when waste saturation was higher. During the experiment, the average dry unit weight of the waste increased 28% and the dry-weight water content (wd) increased 18%; field capacity of the waste was 44 to 48% on a dry-weight basis. Biochemical methane potential decreased from 51.4 to 3.4  mL-CH4/g-dry, indicating that 93% of the potential methane embodied in the waste was removed. The pH of the effluent increased, whereas biochemical oxygen demand (BOD), chemical oxygen demand (COD), and BOD:COD all decreased during dosing. Immediate compression occurred for 1–2 weeks following waste placement, and the immediate compression ratio C′c was 0.23. The average rate of time-dependent compression (C′α) ranged between 0.048 and 0.35 and varied systematically with waste temperature (increasing C′α with increasing temperature). ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000636 [article] Deer track bioreactor experiment : Field-scale evaluation of municipal solid waste bioreactor performance [texte imprimé] / Christopher A. Bareither, Auteur ; Ronald J. Breitmeyer, Auteur ; Craig H. Benson, Auteur . - 2012 . - pp. 658–670. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 6 (Juin 2012) . - pp. 658–670 Mots-clés : Solid  waste  Landfills  Bioreactor  Decomposition  Leachate  Settlement Résumé : The Deer Track Bioreactor Experiment (DTBE) was a field-scale experiment conducted in a drainage lysimeter (8.2-m height, 2.4-m diameter) to assess the physical, chemical, and biological response of municipal solid waste with leachate addition. The experiment was operated for 1,067 days, with leachate dosing initiated on Day 399. Fresh leachate collected from a full-scale landfill was used for each dose. The ratio of cumulative leachate effluent to influent volume increased during dosing and leveled off at approximately 80%, indicating field capacity was achieved. Peak Darcy flux ranged from 2×10−7  m/s to 4×10−5  m/s, with larger flux computed for the last four doses when waste saturation was higher. During the experiment, the average dry unit weight of the waste increased 28% and the dry-weight water content (wd) increased 18%; field capacity of the waste was 44 to 48% on a dry-weight basis. Biochemical methane potential decreased from 51.4 to 3.4  mL-CH4/g-dry, indicating that 93% of the potential methane embodied in the waste was removed. The pH of the effluent increased, whereas biochemical oxygen demand (BOD), chemical oxygen demand (COD), and BOD:COD all decreased during dosing. Immediate compression occurred for 1–2 weeks following waste placement, and the immediate compression ratio C′c was 0.23. The average rate of time-dependent compression (C′α) ranged between 0.048 and 0.35 and varied systematically with waste temperature (increasing C′α with increasing temperature). ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000636

Effects of waste composition and decomposition on the shear strength of municipal solid waste / Christopher A. Bareither in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 10 (Octobre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 10 (Octobre 2012) . - pp.1161–1174. Titre : Effects of waste composition and decomposition on the shear strength of municipal solid waste Type de document : texte imprimé Auteurs : Christopher A. Bareither, Auteur ; Craig H. Benson, Auteur ; Tuncer B. Edil, Auteur Année de publication : 2013 Article en page(s) : pp.1161–1174. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Municipal  solid  waste  Shear  strength  Decomposition  Bioreactor  landfills Résumé : The objective of this study was to evaluate the effects of waste composition and decomposition on the shear strength of municipal solid waste. Waste was collected from two sources (an operating landfill and a transfer station) and degraded in laboratory anaerobic reactors to prepare wastes with different degrees of decomposition. Shear strength was measured in a 280-mm-diameter direct shear ring on nine wastes with normal stress ranging between 12 and 90 kPa. The Mohr-Coulomb failure criterion was used to determine shear strength parameters (ϕ = friction angle and c = cohesion intercept) of the wastes, and shear strength was selected at a horizontal displacement of 56 mm (i.e., 20% of the specimen diameter). A composite failure envelope regressed through shear strength versus normal stress data from all wastes was statistically significant, with ϕ=37° and c=20 kPa. A comparison between tests conducted in this study and in the literature indicates that larger ϕ are obtained for waste with a greater fraction of soil-like, gravel, and inert constituents, whereas lower ϕ are coincident with higher fractions of paper and cardboard or plastic. This effect of waste composition on ϕ is applicable when fibrous particles are primarily parallel with the shear plane, which is the common particle orientation in direct shear. Tests conducted in this study also indicate ϕ increases with decreasing volatile solids or the ratio of cellulose + hemicellulose to lignin (i.e., increasing decomposition). Contrasting correlations have been reported in the literature, attributed to the initial waste composition, which influences the effect of decomposition on ϕ. No correspondence was found between c and waste composition or the degree of waste decomposition. ISSN : 1090-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000702 [article] Effects of waste composition and decomposition on the shear strength of municipal solid waste [texte imprimé] / Christopher A. Bareither, Auteur ; Craig H. Benson, Auteur ; Tuncer B. Edil, Auteur . - 2013 . - pp.1161–1174. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 10 (Octobre 2012) . - pp.1161–1174. Mots-clés : Municipal  solid  waste  Shear  strength  Decomposition  Bioreactor  landfills Résumé : The objective of this study was to evaluate the effects of waste composition and decomposition on the shear strength of municipal solid waste. Waste was collected from two sources (an operating landfill and a transfer station) and degraded in laboratory anaerobic reactors to prepare wastes with different degrees of decomposition. Shear strength was measured in a 280-mm-diameter direct shear ring on nine wastes with normal stress ranging between 12 and 90 kPa. The Mohr-Coulomb failure criterion was used to determine shear strength parameters (ϕ = friction angle and c = cohesion intercept) of the wastes, and shear strength was selected at a horizontal displacement of 56 mm (i.e., 20% of the specimen diameter). A composite failure envelope regressed through shear strength versus normal stress data from all wastes was statistically significant, with ϕ=37° and c=20 kPa. A comparison between tests conducted in this study and in the literature indicates that larger ϕ are obtained for waste with a greater fraction of soil-like, gravel, and inert constituents, whereas lower ϕ are coincident with higher fractions of paper and cardboard or plastic. This effect of waste composition on ϕ is applicable when fibrous particles are primarily parallel with the shear plane, which is the common particle orientation in direct shear. Tests conducted in this study also indicate ϕ increases with decreasing volatile solids or the ratio of cellulose + hemicellulose to lignin (i.e., increasing decomposition). Contrasting correlations have been reported in the literature, attributed to the initial waste composition, which influences the effect of decomposition on ϕ. No correspondence was found between c and waste composition or the degree of waste decomposition. ISSN : 1090-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000702

Geological and physical factors affecting the friction angle of compacted sands / Christopher A. Bareither in Journal of geotechnical and geoenvironmental engineering, Vol. 134 N°10 (Octobre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N°10 (Octobre 2008) . - pp. 1476–1489 Titre : Geological and physical factors affecting the friction angle of compacted sands Type de document : texte imprimé Auteurs : Christopher A. Bareither, Auteur ; Tuncer B. Edil, Auteur ; Craig H. Benson, Auteur Année de publication : 2008 Article en page(s) : pp. 1476–1489 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Sand  Friction  Displacement  Mineralogy  Backfills  Slopes Résumé : This study evaluated the effects of physical characteristics and geologic factors on the shear strength of compacted sands from Wisconsin that are used as granular backfill for mechanically stabilized earth walls and reinforced soil slopes. Physical properties and shear strength were determined for 30 compacted sands collected from a broad range of geological deposits. Relationships between strength/deformation behavior, geologic origin, and physical properties were used to categorize the sands into four friction angle groups. Sands with the lowest friction angle are derived from weathering of underlying sandstones, and tend to be medium-fine, well-rounded, and poorly graded sands. Sands with the highest friction angle are from recent glacial activity and tend to be coarser grained, well-graded, and/or angular sands. A multivariate regression model was developed that can be used to predict friction angle (ϕ′) of compacted sands from comparable geological origins based on effective particle size (D10) , maximum dry unit weight (γdmax) , and Krumbein roundness (Rs) . En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A10%281 [...] [article] Geological and physical factors affecting the friction angle of compacted sands [texte imprimé] / Christopher A. Bareither, Auteur ; Tuncer B. Edil, Auteur ; Craig H. Benson, Auteur . - 2008 . - pp. 1476–1489. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N°10 (Octobre 2008) . - pp. 1476–1489 Mots-clés : Sand  Friction  Displacement  Mineralogy  Backfills  Slopes Résumé : This study evaluated the effects of physical characteristics and geologic factors on the shear strength of compacted sands from Wisconsin that are used as granular backfill for mechanically stabilized earth walls and reinforced soil slopes. Physical properties and shear strength were determined for 30 compacted sands collected from a broad range of geological deposits. Relationships between strength/deformation behavior, geologic origin, and physical properties were used to categorize the sands into four friction angle groups. Sands with the lowest friction angle are derived from weathering of underlying sandstones, and tend to be medium-fine, well-rounded, and poorly graded sands. Sands with the highest friction angle are from recent glacial activity and tend to be coarser grained, well-graded, and/or angular sands. A multivariate regression model was developed that can be used to predict friction angle (ϕ′) of compacted sands from comparable geological origins based on effective particle size (D10) , maximum dry unit weight (γdmax) , and Krumbein roundness (Rs) . En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A10%281 [...]