Publications by authors named "Stephanie C Bolyard"

11 Publications

  • Page 1 of 1

Formation of disinfection byproducts during Fenton's oxidation of chloride-rich landfill leachate.

J Hazard Mater 2020 01 11;382:121213. Epub 2019 Sep 11.

Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States. Electronic address:

Because of the production of chlorine species in leachate during Fenton's oxidation, harmful disinfection byproducts (DBP) can be formed but this has not been well studied before. Herein, we have investigated five classes of DBP: trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, and halonitromethanes during Fenton's oxidation of landfill leachates. The results show that the DBP concentration increased with the increase of [HO]: [Cl] ratio due to the increased concentration of chlorine species. The highest total DBP concentration was 4860 μg L at [HO]: [Cl] = 4.0 and the lowest was 84 μg L at [HO]: [Cl] = 0.25. Both the DBP concentration and DBP toxicity increased with the increase of the [HO]: [Fe] ratio, because of the increased concentration and lifetime of the chlorine species. Most of the DBP were formed during the first minute of the reaction and stayed stable up to 3 h, indicating that DBP may not be preferred targets of hydroxyl radicals in the presence of a large amount of organics. In most cases, trihalomethanes dominated the DBP concentration, while haloacetonitriles dominated the total additive toxicity. This study has provided important implications to understand DBP formation during Fenton's oxidation.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121213DOI Listing
January 2020

Treatment of leachate organic matter through sunlight driven processes.

Waste Manag 2019 Jul 28;94:18-26. Epub 2019 May 28.

California State University, Sacramento, Department of Civil Engineering, 6000 J Street, Sacramento, CA 95819, United States. Electronic address:

Leachate organic matter (LOM) from mature, stabilized landfills is recalcitrant in nature resulting from high concentrations of humic substances, such as humic acids and other complex organic matter. This research focused on the behavior and fate of LOM in aquatic sun-lit systems to address the extent and mechanisms of LOM photodegradation by exposing leachate to natural sunlight in central Florida for a period of 90 days. Transformation processes were measured using ultraviolet-visible (UV-Vis) spectroscopy, fluorescence excitation-emission matrix spectroscopy, size-exclusion chromatography, and chemical oxygen demand over the test period. Results of the study suggest that photolytic, and in some cases biological, reactions were responsible for the reduction of LOM demonstrated by the transformation of high molecular weight recalcitrant material to lower molecular weight material, loss of fluorescence and color, and reduction of UV absorbance.
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http://dx.doi.org/10.1016/j.wasman.2019.05.015DOI Listing
July 2019

Impact of organic matter from leachate discharged to wastewater treatment plants on effluent quality and UV disinfection.

Waste Manag 2019 Apr 27;88:257-267. Epub 2019 Mar 27.

University of Central Florida, Office of Research, 4365 Andromeda Loop N., MH 243, Orlando, FL 32816, United States. Electronic address:

There are growing concerns over the negative effects of leachate organic matter (LOM) on ultraviolet (UV) disinfection and effluent quality when leachate is co-treated with domestic wastewater. In this study, the effects of LOM on wastewater effluent quality were evaluated through field studies at wastewater treatment plants (WWTPs) that receive and do not receive leachate. Impacts of leachate on effluent quality were determined through UV measurements at 254 nm (UV), fluorescence measurements, and the quantification of conventional parameters which included nutrient and organic constituent concentrations. Results showed that some leachate impacts can be observed using UV spectroscopy in wastewater influent and effluent when present at volumetric contributions as low as 0.01%. In addition, leachate impacted wastewater samples showed a higher dissolved organic nitrogen and dissolved organic carbon concentrations in the effluent relative to effluents from WWTPs without leachate. At leachate volumetric contributions greater than or equal to 0.1% (0.10-14.8%), UV transmittance in wastewater effluents was below 65%. A typical guideline for effective UV disinfection at WWTPs is above 65% transmittance. Furthermore, fluorescence characterization of leachate-impacted wastewater showed a higher intensity of humic-like peaks relative to wastewater without leachate. This research provided a better understanding of the potential implications of accepting leachate at WWTPs. These effects, however, can be managed by ensuring that leachate discharge is maintained at acceptable volumetric contributions and evenly spread out over the discharge period.
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http://dx.doi.org/10.1016/j.wasman.2019.03.036DOI Listing
April 2019

Conventional and fourier transform infrared characterization of waste and leachate during municipal solid waste stabilization.

Chemosphere 2019 Jul 6;227:34-42. Epub 2019 Apr 6.

University of Central Florida, Department of Chemistry, 4111 Libra Drive, Physical Sciences 236, Orlando, FL, 32816, USA. Electronic address:

Solid waste and leachate samples from bench-scale anaerobic bioreactors and flushing bioreactors (FBs), containing mature waste were characterized using Fourier Transform Infrared Spectroscopy (FTIR) to provide a better understanding of the changes in waste characteristics when waste transitions from mature to stabilized. Humic acid (HA) extracted from mature waste and waste removed from the FBs were characterized using FTIR and C nuclear magnetic resonance. FBs were operated under three different treatment scenarios (flushing with clean water, recirculation of leachate treated by chemical oxidation, and recirculation of leachate treated by chemical oxidation with waste aeration. FTIR spectra of FB waste and leachate supported the stabilization of waste that occurred after the additional treatment. There was a shift in the dominance of organic to inorganic functional groups when compared to changes in conventional parameters that aligned with published values on waste stability. HA extracted from the mature waste were dominated by aliphatic carbon and aromatic carbon was less intense. Treatment by flushing resulted in a decrease in aliphatic carbon and an increase in aromatic carbon. HA extracted from reactors with oxidized leachate recirculation and aeration decreased in aliphatic carbon content, with minimal change in aromatic carbon. Therefore, the additional treatment did not result in an increase in the reactivity potential of the HA which aligns with FTIR and principal component analysis. Results suggest that spectroscopic techniques could be used to assess the stability of waste samples as opposed to more time-consuming analyses.
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http://dx.doi.org/10.1016/j.chemosphere.2019.04.035DOI Listing
July 2019

A review of the fate of engineered nanomaterials in municipal solid waste streams.

Waste Manag 2018 May 21;75:427-449. Epub 2018 Feb 21.

Department of Water-Atmosphere-Environment, Institute of Waste Management, University of Natural Resources and Life Sciences, Muthgasse 107, 1190 Vienna, Austria.

Significant knowledge and data gaps associated with the fate of product-embedded engineered nanomaterials (ENMs) in waste management processes exist that limit our current ability to develop appropriate end-of-life management strategies. This review paper was developed as part of the activities of the IWWG ENMs in Waste Task Group. The specific objectives of this review paper are to assess the current knowledge associated with the fate of ENMs in commonly used waste management processes, including key processes and mechanisms associated with ENM fate and transport in each waste management process, and to use that information to identify the data gaps and research needs in this area. Literature associated with the fate of ENMs in wastes was reviewed and summarized. Overall, results from this literature review indicate a need for continued research in this area. No work has been conducted to quantify ENMs present in discarded materials and an understanding of ENM release from consumer products under conditions representative of those found in relevant waste management process is needed. Results also indicate that significant knowledge gaps associated with ENM behaviour exist for each waste management process investigated. There is a need for additional research investigating the fate of different types of ENMs at larger concentration ranges with different surface chemistries. Understanding how changes in treatment process operation may influence ENM fate is also needed. A series of specific research questions associated with the fate of ENMs during the management of ENM-containing wastes have been identified and used to direct future research in this area.
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http://dx.doi.org/10.1016/j.wasman.2018.02.012DOI Listing
May 2018

Evaluation of leachate dissolved organic nitrogen discharge effect on wastewater effluent quality.

Waste Manag 2017 Jul 10;65:47-53. Epub 2017 Apr 10.

University of Central Florida, Office of Research and Commercialization, 4365 Andromeda Loop N., MH 243, Orlando, FL 32816, United States. Electronic address:

Nitrogen is limited more and more frequently in wastewater treatment plant (WWTP) effluents because of the concern of causing eutrophication in discharge waters. Twelve leachates from eight landfills in Florida and California were characterized for total nitrogen (TN) and dissolved organic nitrogen (DON). The average concentration of TN and DON in leachate was approximately 1146mg/L and 40mg/L, respectively. Solid-phase extraction was used to fractionate the DON based on hydrophobic (recalcitrant fraction) and hydrophilic (bioavailable fraction) chemical properties. The average leachate concentrations of bioavailable (bDON) and recalcitrant (rDON) DON were 16.5mg/L and 18.4mg/L, respectively. The rDON fraction was positively correlated, but with a low R, with total leachate apparent color dissolved UV, chemical oxygen demand (COD), and humic acid (R equals 0.38, 0.49, and 0.40, respectively). The hydrophobic fraction of DON (rDON) was highly colored. This fraction was also associated with over 60% of the total leachate COD. Multiple leachate and wastewater co-treatment simulations were carried out to assess the effects of leachate on total nitrogen wastewater effluent quality using removals for four WWTPs under different scenarios. The calculated pass through of DON suggests that leachate could contribute to significant amounts of nitrogen discharged to aquatic systems.
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http://dx.doi.org/10.1016/j.wasman.2017.03.025DOI Listing
July 2017

Grand Challenges--Management of municipal solid waste.

Waste Manag 2016 Mar;49:1-2

University of South Carolina, USA. Electronic address:

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http://dx.doi.org/10.1016/j.wasman.2016.02.020DOI Listing
March 2016

Application of landfill treatment approaches for stabilization of municipal solid waste.

Waste Manag 2016 Sep 1;55:22-30. Epub 2016 Feb 1.

University of Central Florida, Office of Research and Commercialization, 4365 Andromeda Loop N., MH 243, Orlando, FL 32816, United States.

This research sought to compare the effectiveness of three landfill enhanced treatment approaches aimed at removing releasable carbon and nitrogen after anaerobic landfilling including flushing with clean water (FB 1), leachate recirculation with ex-situ treatment (FB 2), and leachate recirculation with ex-situ treatment and in-situ aeration (FB 3). After extensive treatment of the waste in the FB scenarios, the overall solids and biodegradable fraction were reduced relative to the mature anaerobically treated waste. In terms of the overall degradation, aeration did not provide any advantage over flushing and anaerobic treatment. Flushing was the most effective approach at removing biodegradable components (i.e. cellulose and hemicellulose). Leachate quality improved for all FBs but through different mechanisms. A significant reduction in ammonia-nitrogen occurred in FB 1 and 3 due to flushing and aeration, respectively. The reduction of chemical oxygen demand (COD) in FB 1 was primarily due to flushing. Conversely, the reduction in COD in FBs 2 and 3 was due to oxidation and precipitation during Fenton's Reagent treatment. A mass balance on carbon and nitrogen revealed that a significant fraction still remained in the waste despite the additional treatment provided. Carbon was primarily converted biologically to CH4 and CO2 in the FBs or removed during treatment using Fenton's Reagent. The nitrogen removal occurred through leaching or biological conversion. These results show that under extensive treatment the waste and leachate characteristics did meet published stability values. The minimum stability values achieved were through flushing although FB 2 and 3 were able to improve leachate quality and solid waste characteristics but not to the same extent as FB 1.
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http://dx.doi.org/10.1016/j.wasman.2016.01.024DOI Listing
September 2016

Evaluation of monitoring indicators for the post-closure care of a landfill for MSW characterized with low lignin content.

Waste Manag 2015 Feb 26;36:222-9. Epub 2014 Nov 26.

Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, PR China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of PR China (MOHURD), PR China. Electronic address:

To understand the applicability of the termination indicators for landfill municipal solid waste (MSW) with low initial lignin content, four different accelerated landfill stabilization techniques were applied to anaerobic landfilled waste, including anaerobic flushing with water, anaerobic flushing with Fenton-treated leachate, and aerobic flushing with Fenton-treated and UV/H2O2-treated leachate. Termination indicators, including total organic carbon (TOC), ammonia-N (NH4(+)-N), the ratio of UV absorbance at 254 nm to TOC concentration (SUVA254), fluorescence spectra of leachate, methane production, oxygen consumption, lignocellulose content, and humus-like content were evaluated. Results suggest that oxygen consumption related indicators used as a termination indicator for low-lignin-content MSW were more sensitive than methane consumption related indicators. Aeration increased humic acid (HA) and (HA+FA)/HyI content by 2.9 and 1.7 times compared to the anaerobically stabilized low-lignin-content MSW. On the other hand, both the fulvic acid (FA) and hydrophilic (HyI) fractions remained constant regardless of stabilization technique. The target value developed for low-lignin-content MSW was quite different than developed countries mainly due to low residual biodegradable organic carbon content in stabilized low-lignin-content MSW.
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http://dx.doi.org/10.1016/j.wasman.2014.10.031DOI Listing
February 2015

Behavior of engineered nanoparticles in landfill leachate.

Environ Sci Technol 2013 Aug 10;47(15):8114-22. Epub 2013 Jul 10.

Civil, Environmental, and Construction Engineering , University of Central Florida, 4000 Central Florida Boulevard, Eng I, Room 340, Orlando, Florida, 32816, United States.

This research sought to understand the behavior of engineered nanoparticles in landfill leachate by examining the interactions between nanoparticles and leachate components. The primary foci of this paper are the effects of ZnO, TiO2, and Ag nanoparticles on biological landfill processes and the form of Zn, Ti, and Ag in leachate following the addition of nanoparticles. Insight into the behavior of nanoparticles in landfill leachate was gained from the observed increase in the aqueous concentrations over background for Zn, Ti, and Ag in some tested leachates attributed to leachate components interacting with the nanoparticle coatings resulting in dispersion, dissolution/dissociation, and/or agglomeration. Coated nanoparticles did not affect biological processes when added to leachate; five-day biochemical oxygen demand and biochemical methane potential results were not statistically different when exposed to nanoparticles, presumably due to the low concentration of dissolved free ionic forms of the associated metals resulting from the interaction with leachate components. Chemical speciation modeling predicted that dissolved Zn in leachate was primarily associated with dissolved organic matter, Ti with hydroxide, and Ag with hydrogen sulfide and ammonia; less than 1% of dissolved Zn and Ag was in the free ionic form, and free ionic Ti and Ag concentrations were negligible.
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http://dx.doi.org/10.1021/es305175eDOI Listing
August 2013
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