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Treatment of Leachate Organic Matter through Sunlight Driven Processes
Title
Treatment of Leachate Organic Matter through Sunlight Driven Processes.
Creator
Lozinski, Duncan, Reinhart, Debra, Lee, Woo Hyoung, Bolyard, Stephanie, University of Central Florida
Abstract / Description
The ability to manage leachate during post-closure care (PCC) of a landfill may be increasingly difficult as leachate organic matter (LOM) becomes recalcitrant when a landfill ages, requiring advanced and costly treatment technologies. This research investigated the ability to treat LOM through sunlight driven processes, with a focus on photolysis, to provide insight to landfill owners and operators on the potential of wetlands treatment as a means for reducing long-term risks and costs...
Show moreThe ability to manage leachate during post-closure care (PCC) of a landfill may be increasingly difficult as leachate organic matter (LOM) becomes recalcitrant when a landfill ages, requiring advanced and costly treatment technologies. This research investigated the ability to treat LOM through sunlight driven processes, with a focus on photolysis, to provide insight to landfill owners and operators on the potential of wetlands treatment as a means for reducing long-term risks and costs associated with leachate treatment during PCC. The study was completed in eight batch tests, where leachate was exposed to natural sunlight in central Florida for a period of 90 days. It was hypothesized that through photolytic reactions, in particular photolysis, high molecular weight recalcitrant LOM would be degraded to labile, low molecular weight material. To identify the treatment mechanisms, transformation processes were measured using ultraviolet-visible (UV-Vis) spectroscopy, fluorescence excitation-emission matrix spectroscopy (EEMs), size-exclusion chromatography (SEC), and chemical oxygen demand (COD) from the beginning to the end of the test period. Additionally, the ability for nitrogen species to become bioavailable when exposed to sunlight was evaluated for two of the leachate samples using solid-phase extraction (SPE) to fractionate recalcitrant dissolved organic nitrogen (rDON) and bioavailable dissolved organic nitrogen (bDON). Results suggest that treatment of LOM through sunlight driven processes is possible. Treatment is dependent upon the dilution of leachate and characteristics of the LOM. Dilution must be high enough to allow sunlight to penetrate the depth of the liquid. UV-Vis, EEMs, and SEC show that high molecular weight recalcitrant material is undergoing transformation into lower molecular weight material as a result of photolytic and likely biological reactions promoted by sunlight. The ability for nitrogen to become bioavailable when exposed to sunlight was shown to be dependent upon nitrogen concentrations in the sample.
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Date Issued
2018
Identifier
CFE0007044, ucf:51987
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007044
Fate of Coated Zinc Oxide in Municipal Solid Waste Landfills
Title
Fate of Coated Zinc Oxide in Municipal Solid Waste Landfills.
Creator
Bolyard, Stephanie, Reinhart, Debra, Santra, Swadeshmukul, Randall, Andrew, University of Central Florida
Abstract / Description
Given the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the...
Show moreGiven the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the proper handling of these novel materials from cradle to grave; such research will provide information on how these NMs can be safely introduced into the environment. This research seeks to understand the fate of NMs within waste environments by examining the interactions between NMs and landfill leachate components. The primary focus of this thesis is the effect of Zinc Oxide (ZnO) on biological landfill processes, solids aggregation, and chemical speciation of Zn in landfill leachate following the addition of crystalline, nano-sized ZnO coated with triethoxycaprylylsilane. This research (1) observed the effects of coated ZnO on five-day biochemical oxygen demand (BOD5) and biochemical methane potential (BMP), (2) examined effects of solids aggregation on the fate of ZnO, (3) quantified the concentration of Zinc (Zn) by size fractions, and (4) modeled the chemical speciation of Zn in landfill leachate using Visual MINTEQ.No change in dissolved Zn was observed after coated ZnO was exposed to (")middle-aged(") leachate. Upon exposure to (")mature(") leachate there was an increase in dissolved Zn assumed to be a result of the dissociation of ZnO. Solids data supported the aggregation of particles in both middle aged and mature leachate. There was an increase in the Zn concentration in leachate fractions greater than 1500 nm presumably due to the dispersion of normally insoluble ZnO nanoparticles (NPs) following the interaction with humic acids (HA). ZnO did not inhibit anaerobic or aerobic processes in either middle aged or mature leachate, presumably due to the relatively low concentration of dissolved ionic Zn. Despite the observation of increased dissociation upon exposure to mature leachate, the presence of dissolved organic matter (DOM) may have hindered the ability for dissolved ionic Zn to become bioavailable. Fractionation, BOD5 and BMP tests, and chemical speciation modeling provided insight on the mobility of ZnO in landfills and the absence of inhibitory effects on landfill processes. Aggregation of ZnO NPs may prevent movement through traditional containment systems (i.e. geomembrane liners) due to the increased particle size. However, the increased dispersion suggests that ZnO NPs will be transported out of the landfill in the leachate, however biological treatment of leachate should be unaffected by the presence of ZnO. The bioavailability of Zn was not substantially affected by the presence of ZnO due to affinity of dissolved Zn for DOM. However, due to the heterogeneity of landfill leachate and the utilization of different NM coatings, it is challenging to predict the overall mobility of other NMs in a landfill.
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Date Issued
2012
Identifier
CFE0004264, ucf:49509
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004264
Application of Landfill Treatment Approaches for the Stabilization of Municipal Solid Waste
Title
Application of Landfill Treatment Approaches for the Stabilization of Municipal Solid Waste.
Creator
Bolyard, Stephanie, Reinhart, Debra, Santra, Swadeshmukul, Randall, Andrew, University of Central Florida
Abstract / Description
This research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ...
Show moreThis research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ aeration were evaluated. After extensive treatment of the waste in the flushing bioreactor (FB) scenarios, the overall biodegradable fraction was reduced relative to mature waste. Leachate quality improved for all FBs but through different mechanisms. Flushing was the most effective approach at removing biodegradable components and improving leachate quality. A mass balance on carbon and nitrogen revealed that a significant fraction still remained in the waste. Solid waste and leachate samples from the anaerobic bioreactors and FBs were characterized using Fourier Transform Infrared (FTIR) to provide a better understanding of changes in waste characteristics when waste transitions from mature to stabilized. Organic functional groups associated with aliphatic methylene were present in leachate and solid waste samples during the early stages of anaerobic degradation and disappeared once these wastes underwent treatment. Once the waste was stabilized, the FTIR spectra of leachate and solid waste were dominated by inorganic functional groups (carboxylic acid/carbonate group, carbonate, quartz, and clay minerals). Leachate is commonly co-treated with domestic wastewater due to the cost and complexity of on-site treatment. The organic constituents in leachate can be problematic for WWTPs as their recalcitrant components pass through conventional treatment processes, impacting effluent quality. Twelve leachates where characterized for total nitrogen (TN) and dissolved organic nitrogen (DON). The average concentration of TN and DON in leachate was 1,160 and 40.7 mg/L, respectively. Leachates were fractionated based on hydrophobic (recalcitrant; rDON) and hydrophilic (bioavailable; bDON) properties. The average concentrations of bDON and rDON were 16.5 and 18.4 mg/L, respectively. Multiple leachate and wastewater co-treatment simulations were carried out to assess the treatment of leachate nitrogen at historic nitrogen removal levels of four WWTPs and the effects on wastewater effluent quality for four WWTPs. The effluent quality exceeded typical TN limits of 3 to 10 mg/L at leachate volumetric contributions of 10%. The maximum calculated pass through concentrations of rDON and DON at 10% volumetric contribution for the twelve leachates was 4.77 and 9.71 mg/L, respectively. The effects of LOM on wastewater effluent quality was further evaluated in the field. Results showed that leachate detection for each field study could be determined using UV254 nm absorbance. DON and dissolved organic carbon (DOC) concentrations increased at significant levels in leachate-impacted wastewater samples. The DON decreased through the treatment train, suggesting that this parameter was effectively removed, while DOC persisted. DOC pass through coincided with an increase in color and UV254 nm absorption. In effluents, the UV254 nm transmittance was just below the minimum 65% disinfection requirement at dilutions greater than 1%. Leachate-impacted wastewater showed a higher concentration of humic-like peaks during fluorescence measurements than wastewater without leachate.
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Date Issued
2016
Identifier
CFE0006076, ucf:50959
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006076