@article{saquing_knappe_barlaz_2012, title={Fate and transport of phenol in a packed bed reactor containing simulated solid waste}, volume={32}, ISSN={["0956-053X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-82655173775&partnerID=MN8TOARS}, DOI={10.1016/j.wasman.2011.09.017}, abstractNote={An assessment of the risk to human health and the environment associated with the presence of organic contaminants (OCs) in landfills necessitates reliable predictive models. The overall objectives of this study were to (1) conduct column experiments to measure the fate and transport of an OC in a simulated solid waste mixture, (2) compare the results of column experiments to model predictions using HYDRUS-1D (version 4.13), a contaminant fate and transport model that can be parameterized to simulate the laboratory experimental system, and (3) determine model input parameters from independently conducted batch experiments. Experiments were conducted in which sorption only and sorption plus biodegradation influenced OC transport. HYDRUS-1D can reasonably simulate the fate and transport of phenol in an anaerobic and fully saturated waste column in which biodegradation and sorption are the prevailing fate processes. The agreement between model predictions and column data was imperfect (i.e., within a factor of two) for the sorption plus biodegradation test and the error almost certainly lies in the difficulty of measuring a biodegradation rate that is applicable to the column conditions. Nevertheless, a biodegradation rate estimate that is within a factor of two or even five may be adequate in the context of a landfill, given the extended retention time and the fact that leachate release will be controlled by the infiltration rate which can be minimized by engineering controls.}, number={2}, journal={WASTE MANAGEMENT}, author={Saquing, Jovita M. and Knappe, Detlef R. U. and Barlaz, Morton A.}, year={2012}, month={Feb}, pages={327–334} } @article{saquing_saquing_knappe_barlaz_2010, title={Impact of Plastics on Fate and Transport of Organic Contaminants in Landfills}, volume={44}, ISSN={["0013-936X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77956547698&partnerID=MN8TOARS}, DOI={10.1021/es101251p}, abstractNote={Factors controlling organic contaminant sorption to common plastics in municipal solid waste were identified. Consumer plastics [drinking water container, prescription drug bottle, soda bottle, disposable cold cup, computer casing, furniture foam, carpet, vinyl flooring, formica sheet] and model polymers [high-density polyethylene (HDPE), medium-density polyethylene, low-density polyethylene, poly(vinyl chloride) (PVC)] were characterized by X-ray diffractometry, differential scanning calorimetry, and elemental analysis. The material characterization was used to interpret batch isotherm and kinetic data. K(p) values describing toluene sorption to rubbery or "soft" polymers could be normalized by the amorphous polymer fraction (f(amorphous)) but not by the organic carbon fraction (f(oc)). Diffusion coefficients (D) describing the uptake rate of toluene by rubbery plastics (HDPE, drinking water container, prescription drug bottle) were similar (D approximately 10(-10) cm(2)/s), indicating that pure HDPE can be used as a model for rubbery plastics. Toluene diffusivity was similar among glassy or "hard" plastics (PVC, soda bottle, computer casing, disposable cold cup; D approximately 10(-12) cm(2)/s) but lower than for rubbery plastics. Plastics in landfills are potential sinks of hydrophobic organic contaminants (HOCs) because of their higher affinity for HOCs compared to lignocellulosic materials and the slow desorption of HOCs from glassy plastics.}, number={16}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Saquing, Jovita M. and Saquing, Carl D. and Knappe, Detlef R. U. and Barlaz, Morton A.}, year={2010}, month={Aug}, pages={6396–6402} } @article{barlaz_bareither_hossain_saquing_mezzari_benson_tolaymat_yazdani_2010, title={Performance of North American Bioreactor Landfills. II: Chemical and Biological Characteristics}, volume={136}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000220}, abstractNote={The objective of this research was to examine the performance of five North American bioreactor landfills. This paper represents the second of a two-part series and addresses biological and chemical aspects of bioreactor performance including gas production and management, and leachate chemistry. The data support accelerated methane generation at several landfills ( k=0.08–0.21 1/year ) relative to the AP-42 default decay rate ( k=0.04 1/year ) . While the data indicate that gas collection increases at bioreactor landfills, a general relationship between decay rate and moisture added or wet weight water content could not be identified. There was no indication that gas collection increases appreciably when the water content reaches 40%. Most of the leachates at the landfills in this study were commingled from cells operating as a bioreactor and conventionally. Nevertheless, trends in pH and BOD:COD in the bioreactor leachates were consistent with the impacts of enhanced biological activity. Ammonia concent...}, number={8}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Barlaz, Morton A. and Bareither, Christopher A. and Hossain, Azam and Saquing, Jovita and Mezzari, Isabella and Benson, Craig H. and Tolaymat, Thabet M. and Yazdani, Ramin}, year={2010}, month={Aug}, pages={839–853} } @article{saquing_mitchell_wu_wagner_knappe_barlaz_2010, title={Factors Controlling Alkylbenzene and Tetrachloroethene Desorption from Municipal Solid Waste Components}, volume={44}, ISSN={["0013-936X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-75749108559&partnerID=MN8TOARS}, DOI={10.1021/es9030672}, abstractNote={Desorption rates of toluene, o-xylene and tetrachloroethene from individual municipal solid waste components [high-density polyethylene (HDPE); poly(vinyl chloride) (PVC); office paper; newsprint; and rabbit food, a model food and yard waste] were determined. Effects of sorbent and sorbate properties, solvent composition (ultrapure water, acidogenic and methanogenic leachates), and contact time ("aging") on desorption rates were evaluated. Hydrophobic organic contaminant (HOC) desorption from PVC and HDPE could be described with a single-parameter polymer diffusion model. In contrast, a three-parameter, biphasic polymer diffusion model was required to describe HOC desorption rates from biopolymer composites. In general, HOC desorption rates from plastics were rapid for HDPE (D = 10(-10) cm(2)/s), a rubbery polymer, but slower for PVC (D = 10(-13)-10(-14) cm(2)/s), a glassy polymer. For biopolymer composites, a large fraction of sorbed HOCs was rapidly released (D(r) = 10(-9)-10(-10) cm(2)/s) while the remaining fraction desorbed slowly (D(s) = 10(-11)-10(-16) cm(2)/s). The toluene desorption rate from PVC was 1 order of magnitude faster in acidogenic leachate than in either ultrapure water or methanogenic leachate, a result that was primarily attributed to the plasticizing effect of volatile fatty acids in acidogenic leachate. For biopolymer composites, small increases in the slowly desorbing HOC fraction were observed with increasing aging time.}, number={3}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Saquing, Jovita M. and Mitchell, Lisa A. and Wu, Bingyan and Wagner, Travis B. and Knappe, Detlef R. U. and Barlaz, Morton A.}, year={2010}, month={Feb}, pages={1123–1129} } @misc{teuten_saquing_knappe_barlaz_jonsson_bjorn_rowland_thompson_galloway_yamashita_et al._2009, title={Transport and release of chemicals from plastics to the environment and to wildlife}, volume={364}, number={1526}, journal={Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences}, author={Teuten, E. L. and Saquing, J. M. and Knappe, D. R. U. and Barlaz, M. A. and Jonsson, S. and Bjorn, A. and Rowland, S. J. and Thompson, R. C. and Galloway, T. S. and Yamashita, R. and et al.}, year={2009}, pages={2027–2045} }