Search

In urban environments, ozone air pollution, poses significant risks to respiratory health. Fixed site monitoring is the primary method of measuring ozone concentrations for health advisories and pollutant reduction, but the spatial scale may not reflect the current population distribution or its future growth. Moreover, formal methods for the placement of ozone monitoring sites within populations potentially omit important spatial criteria, producing monitoring locations that could unintentionally underestimate the exposure burden. Although air pollution affects all people, the combination of underlying health, socioeconomic and demographic factors exacerbate the impact for socially vulnerable population groups. A need exists for assessing the spatial representativeness and data gaps of existing pollution sensor networks and to evaluate future placement strategies of additional sensors. This research also seeks to understand how air pollution monitor placement strategies may neglect social vulnerabilities and therefore, potentially underestimate exposure burdens in vulnerable populations.

Human activities can change the concentration, chemical composition, and properties of atmospheric particulate matter (PM). A quantitative understanding of human impacts on PM is essential for accurate modeling of anthropogenic climate forcing and for regulating air quality. The tropical forests of Amazonia play a critical role in the regional and global climates. Urbanization and deforestation in the region have intensified in the last decades, and yet a quantitative knowledge on the impacts of these activities on PM is scarce. This thesis presents field measurements of submicron PM concentration, composition and optical properties in central Amazonia, with a focus on delineating the anthropogenic impact on the observed quantities. Emphasis is given to organic material, the dominant PM component in the region. The primary site of the studies was located 70 km to the west of Manaus, a city of over two million people in the heart of the Brazilian Amazon. Datasets were collected during the wet and dry seasons of 2014 as part of the GoAmazon2014/5 experiment. The main datasets were obtained by a high-resolution time-of-flight aerosol mass spectrometer (AMS), and additional data from a large suite of instrumentation were employed in the analyses. Positive-matrix factorization (PMF) of organic mass spectra allowed for the classification of the organic PM into its component classes. During the wet season, the effects of the Manaus urban plume were investigated. Fuzzy c-means clustering (FCM) was applied to concentrations of pollution indicators and identified four clusters, which represented distinct background and polluted conditions. When crossed with the AMS and PMF results, increases of up to 200% in PM mass concentrations for polluted compared to background conditions were identified, corresponding to average concentrations as high as 3 µg m-3 and as low as 1 µg m-3, respectively. The pollution-induced changes in the composition of secondary organic PM1 suggested (i) a shift in pathways of organic PM production from HO2- to NO-dominant, and (ii) an acceleration of the atmospheric processing of organic PM. Nitrogen oxides were indicated to play a critical role in both processes. In another study, the influences of the Manaus plume on the pathway of PM production from isoprene epoxydiols (IEPOX) were investigated in detail. The “IEPOX-SOA” factor served as a surrogate for IEPOX-derived PM. This factor had a bi-variate dependence on sulfate and NOy, which was reasoned through the chemical mechanism. For an approximately fixed sulfate concentration, a change in NOy concentrations from 0.5 to 2 ppb was associated with a decrease in IEPOX-SOA factor loadings of two- to three-fold. It was found that the Manaus pollution plume elevated concentrations of NOy more significantly than of sulfate over background. It was therefore concluded that the suppressing effects of increased NO often prevailed over the enhancing effects of increased sulfate on the production of IEPOX-derived PM in the region. During the dry season, the importance of biomass burning increased, and the final study focused on quantifying the anthropogenic contributions to light-absorbing organic PM (brown carbon, BrC). Optical properties were determined from aethalometer measurements. The relationships of the absorption coefficient of BrC at 370 nm with AMS-measured quantities suggested that BrC absorption was associated with less oxidized and nitrogen-containing organic compounds, and that atmospheric processing caused bleaching of the BrC. Estimates of the effective mass absorption efficiencies associated with each class of organic PM (i.e., PMF factor) were obtained through multi-variate linear regression. Together, urban and biomass burning emissions were estimated to contribute on average to 90% of the absorption by organic PM, while they contributed to about 40% of organic PM mass concentrations.

Rising methane in earth’s atmosphere accelerates climate change, and natural gas is a major driver of that increase. In 2016, Massachusetts passed a law requiring that ‘environmentally significant’ leaks in the aging natural gas distribution network be prioritized for repair in an effort to reduce methane emissions. This research seeks to inform implementation of this legislation by determining an efficient method for identifying and rank-ordering leaks according to volume. Participating gas utilities selected 72 Grade 3 gas leaks across the state, representing all leak-prone pipe materials (cast iron, wrought iron, bare steel, coated steel, and old plastic) and pressures ranging from 0.5 – 99 PSI. A previous study found a heavy-tailed distribution of natural gas leaks by volume in a cast iron low-pressure leak population, and I used the same verified chamber measure of leak volume to test whether that relationship held in a diverse set of pipe materials and pressures. The chamber method flux measures were then used to benchmark other methods, including the initially proposed bar hole method. Suspecting that the bar hole method may be insufficient to rank-order leaks by volume, we also tested four additional methods, including the leak footprint, ringdown spectrometer, FLUXBar , and MSS camera. Both the FLUXBar and the MSS camera are innovative new technologies, with the FLUXBar a co-creation of my research coalition. I helped to assemble and maintain an unusually broad coalition of stakeholders in order to carry out this research collaboration between the utilities and local environmental organizations, including legislators and regulators to ensure that the science would drive policy. By replicating the heavy-tail distribution in our more varied leak population, I was able to confirm that the identification of the largest volume leaks (LVLs) would maximize emissions reduction per dollar spent. As the ‘bar hole %gas’ method showed no correlation with leak volume, employing it to identify those LVLs would be as efficient as random selection. Alternate methods did better, with the ringdown spectrometer method, the FLUXBar, and leak footprint methods all correlating with leak volume. The ringdown spectrometer demonstrated the weakest correlation and the use of the FLUXBar is limited by the need for a compressor truck. Leak footprint is not, and can be easily deployed in standard leak surveys. The leak footprint method correlates strongly, so selects leaks that are larger than average leaks, resulting in a return on investment to the ratepayer of less than a year. The originally proposed bar hole method’s return on investment to the ratepayer would be more than six years. These data suggest that the leak footprint is the best available rapid indicator of leak volume, with the FLUXBar measure a potential quantification and verification tool. Continued research is needed as technology-based options advance to meet this challenge. The stakeholder coalition, in response to these data, agreed to a plan to implement the leak footprint method, accelerate repair, and establish transparency, verification and reassessment processes. The agreement between the three largest gas utilities in Massachusetts and my research team, if enacted as designed over the next two years, has the potential to result in a methane emissions reduction equivalent to 4% of the greenhouse gas emissions inventory for Massachusetts.

The uptake of molecules onto atmospheric particles can be influenced by particle viscosity and physical state because of effects on species diffusivity. Relative humidity is a key regulator. Herein, the uptake of gas-phase levoglucosan and 2,4-dinitrophenol was studied from 10% to >95% relative humidity (RH). The uptake was studied for organic particles produced by α-pinene ozonolysis as well as ammonium sulfate salt particles. Levoglucosan and 2,4-dinitrophenol are two medium-sized, atmospherically relevant organic molecules, both emitted to the atmosphere primarily by biomass burning. The results show that levoglucosan uptake depended strongly on particle physical state. For aqueous sulfate particles, uptake increased continuously for higher particle water content at higher RH, tripling from 40% to >95% RH. The implied effective Henry’s law constant changed from (1.2 ± 0.1) × 10^8 to (2.1 ± 0.2) × 10^8 M atm^-1 across this RH range. For the organic particles, levoglucosan uptake increased from 10% to 40% RH in conjunction with a decrease in viscosity and an increase in molecular diffusivity. The implication is a kinetic limit on uptake across this RH range. The estimated diffusivity at 40% RH was 10^(19±0.05) m^2 s^-1. The uptake saturated above 40% RH, suggesting a transition to a thermodynamic regime that regulated maximum uptake. The effective Henry’s law constant was (1.2 ± 0.1) × 10^8 M atm^-1. By comparison, the uptake of 2,4-dinitrophenol onto the organic particles was not significant across the studied RH range. The explanation may be the vapor pressure of 2,4-dinitrophenol was too high to favor significant uptake, suggesting an absence of strong effects on activity coefficients within the organic particle matrix. The effective Henry’s law constant should be less than 3.9 × 10^5 M atm^-1 at 80% to explain the observations. The results reported herein highlight that molecular uptake of gases onto particles can be regulated by both kinetic and thermodynamic factors, either of which can limit the uptake of medium-sized organic molecules by atmospherically relevant particles.

Mounting stressors to existing water supplies, whether by increased human consumption or changing environmental conditions, are creating water shortages worldwide. Consequently, meeting future water demand will require more sophisticated water treatment technologies. In particular, the next generation of water treatment will need to operate with less energy, treat a wider range of contaminants, and offer a greater degree of selectivity for contaminant removal. One way this can be accomplished is through the use of electrochemical water treatment in which electricity is used to remove contaminants by inducing faradaic or electrolytic reactions in solution. Although there are a number of open questions within the field of electrochemical water treatment, this dissertation aims to address two main issues. First, techniques are presented to improve the material properties of carbon-based materials that are frequently used as electrodes in electrochemical water treatment. Carbon is favored for its chemical stability and high surface area, and tailoring the nanoscale structure of the electrodes can further improve desirable properties like ion transport, electrical conductivity, and electrode stability. Methods are presented to control the electrical properties of carbon nanotube and graphene-based electrodes through changes in microscopic morphology and chemical surface doping. Second, the effect of flow-cell architecture on capacitive deionization (CDI) performance is studied in depth. CDI is an electrolytic separation process that removes ions from solution using a pair of charged porous electrodes. Differences in salt storage capacity, the average salt adsorption rate, and charge efficiency were observed depending on the direction of flow relative to the electric field. By addressing fundamental questions in the field of electrochemical water treatment, these studies contribute to future progress in water treatment.

Energy demand in buildings in Albania represents a challenge for the country, which is committed to reduce its carbon footprint by 22% in 2020, and implement green building efficiency measures in an attempt to fulfill EU legislation requirements. In this regard, the Albanian building industry has been highly receptive to “green” growth, witnessing an era of high demand for green buildings. Although the demand and commitment for greening the construction sector is increasing, the country still lacks a comprehensive framework to lead the building sector towards the road of sustainability. The main objective of this study was to provide information for the development of a regional sustainability framework with green building parameters specific to Albania’s environment. The hypothesis this study evaluated is that developing a regional green building rating system, focused on measures that lower the energy consumption of buildings in Albania, is an effective instrument for achieving the 22% GHG emission reduction goal by 2020. In order to define the criteria to be applied, it is crucial to answer questions such as: (i) What is the energy saving potential and GHG emission reduction of a “typical” building in Albania? (ii) What energy conservation measures will be most effective in reducing energy consumption and GHGs? The best building practices were evaluated taking into consideration the local climate and regional priorities, while highlighting parameters that yield the best energy efficiency outcomes. To narrow the scope, this research focused on the building stock of the city of Tirana, which was used as a “typical” city in Albania. Performance-based building energy modeling was used as the core of this research protocol, and four building typologies were modeled to assess the energy efficiency of buildings. The building typologies represented the three different building sectors of commercial, residential and public buildings. The energy simulations were conducted using the Urban Modeling Interface (UMI) software, which is a Rhino-based simulation engine designed to model the environmental performance of neighborhoods and cities with respect to operational and embodied energy. The results of the study quantify the energy saving potential and GHG emission reduction impact for the city of Tirana. The study demonstrated that the building sector in Tirana has great potential for energy improvements with projected energy savings and GHG emission reduction of 42% at the city level, resulting in environmental pollution reduction and a healthier quality of life for building occupants. This showed that the city could achieve the 22% GHG emission reduction goal by 2020 targeting the building sector alone, supporting the hypothesis of the study. Following the energy modeling analysis, a set of sustainable practices for buildings in this region were recommended. The implementation of these measures are projected to have the highest impact in the residential building sector with 47% projected energy savings, compared to 30% in commercial buildings and 36% in public buildings in Tirana. This makes the residential building sector a priority for the implementation of these measures. In addition to advancing the state of knowledge in the field of green buildings, this research could serve as the basis for the development of the sustainability framework with best building practices to be applied for decision makers, developers and policymakers for improving the sustainability performance of buildings in Albania.

The offshore Pitas Point and onshore Ventura faults are aligned along strike, which has led some in the geological community to propose their connection at depth. However, this connection requires that onshore and offshore fault segments have similar subsurface geometries. This project presents an analysis of the subsurface geometry and kinematics of the Pitas Point fault to assess this potential linkage with the Ventura fault via the Sisar decollement. Our analysis specifically focuses on the region beneath the Dos Cuadras anticline in the eastern Santa Barbara Channel, where we constrain and render the geometry of the Pitas Point fault using 3-D seismic reflection data and well control. We determine a permissible range of fault geometries through seismic interpretation, cross section construction, and balancing. The Pitas Point fault is comprised of several splays. Our analysis suggests that the main splay (referred to as the Upper Pitas Point fault (UPP)), has a listric geometry -shallowing its dip with depth. The UPP fault soles to the regional detachment at about 8.1 km. A similar mid-crustal detachment has been proposed for the onshore Ventura fault (Sisar decollement), and mapped to the south of our study area as the Lower Pitas Point fault (LPP). This common detachment provides a direct structural linkage between the Upper Pitas Point and Ventura faults, supporting the proposal that these structures are part of a combined fault system. We combine this new fault interpretation with elements of the SCEC Community Fault Model to generate a complete representation of the Ventura, Pitas Point, and Southern San Cayetano fault (V-PP-SSC) system, which has a combined surface area of about 2610 km2. Utilizing the slip rate range of 6.6-10.5 mm/yr as presented by Hubbard et al. (2014) and corroborated by Marshall et al. (2017), we calculate potential maximum moment magnitude (7.4) and a recurrence interval (125-290 years) for earthquakes on this system. Due to the nature of the Santa Barbara Channel and Ventura basins, and high slip rates for the V-PP-SSC system, the combined fault system described in this study poses great risk to the urban populations of southern California.

Amazon forests are potentially an important sink of atmospheric carbon dioxide (CO2). However, the present magnitude of net CO2 uptake by intact Amazon forests and the controls upon seasonal, yearly, and decadal variability in their net CO2 sequestration and emission are not well understood. Across space and time, changes in meteorology, phenology, and disturbance can all affect the net ecosystem-atmosphere exchange of carbon (NEE). Forest NEE can be estimated using direct atmospheric eddy covariance measurements, but systematic measurement biases can make accurate estimates of the long-term direction and magnitude of the net carbon balance challenging. We present a 3.5-year update to a previously published 4-year record of hourly eddy covariance-derived NEE from an evergreen Eastern Amazon forest. To address biases resulting from subjective quality control (QC) of NEE data, we introduced QC criteria that were naïve to final NEE values. We also corrected poor calibrations that resulted in physically unrealistic CO2 concentrations, recovering 9% of all eddy covariance data before QC data removal (4.5% after removal). The new 3.5-year raw NEE data record had 74% coverage over all hours, compared with 78% coverage in the previous 4-year data record. The criteria produced annual NEE that were consistent with previously reported totals for the first 4 years. To partition influences upon interannual variability in NEE, we use a statistical model to represent NEE at our Eastern Amazon forest site as a constant response to changing meteorology and phenology throughout a decade. Our model simulated mean annual NEE well, with exception to the first year of our data record in 2002, during which the total residual emission was 1.2 MgC ha-1 because photosynthesis was anomalously low. We confirmed that a severe drought occurred in 1998, four years prior to our data record. We hypothesize that this drought caused a persistent disturbance through 2002. We estimated tree mortality of 12%-31% of aboveground biomass following the 1998 drought-disturbance, but there was no evidence that 21st century droughts disturbed this region of evergreen Amazon forest. Our results suggest that legacy effects of drought may impact photosynthesis via partial damage to still-living trees. Systematic biases in the total magnitude of NEE are typically associated with low-turbulence conditions at night. We developed a two-step bias correction, which makes different assumptions than the conventional friction velocity (u*) filter correction, assumptions that are supported by prior measurements of subcanopy advective divergence loss of nighttime flux. We applied both the convention correction and our novel correction to our Eastern Amazon site, an additional Amazon forest site, and a temperate forest site. Plausible u* filters led to implausible decadal carbon budgets at both Amazon forest sites. Conversely, our novel correction eliminated the dependence of nighttime NEE on u*, produced estimates for the mean advective lost nighttime flux that agreed with measurements made during growing seasons at two sites, and produced plausible decadal carbon budgets at both Amazon forest sites. Our NEE bias correction is a necessary alternative to the u* filter, but requires year-round growing seasons and multi-year data records.

The warming of the Arctic, as mediated by climate change, will precipitate a feedback effect. Should the carbon in soil be processed and emitted as the greenhouse gases CO2 and CH4, the feedback effect will be positive; if, however, increased plant growth draws down sufficient atmospheric CO2 to overwhelm emission mechanisms, the feedback will be negative. High resolution measurements of CO2 and CH4 emissions are critical to understanding how the changing Arctic biome will respond to, and, in turn, influence climate change. Yet the sparsity of infrastructure and population in the Arctic precludes widespread monitoring of carbon emissions and uptake in the Arctic, hindering understanding of the mechanisms which control the feedback effects of a warming Arctic. In response to these issues, we present a new CO2 Herriott Cell that operates in conjunction with a NOAA Best Air Turbulence probe on a lightweight DA-42 aircraft. The CO2 Herriott cell employs a tunable mid-IR Quantum Cascade Laser to measure CO2 and its isotopologues via direct absorption in a Herriott Cell. The CO2 Herriott cell demonstrates in-laboratory precision of 1ppmv (1 sec). We describe the development of the instrument, as well as our calibration and precision assessment protocols in the laboratory, in detail. In chapter 2, we report on the field deployment of the instrument suite in the North Slope of Alaska in August of 2013. Owing to differences between field deployment conditions and laboratory conditions, our instrument did not perform to specification in the field. Thus, in chapter 3, we examine the sources of instrument performance deterioration in the field. We provide as well corrections to field data carried out in the laboratory after the mission, and the subsequent recovered 12CO2 data from five flights of the field campaign, demonstrating proof-of-concept of the CO2 Herriott instrument. Finally, we offer suggested instrument augmentations to ensure the capacity to measure fluxes in-situ during future field deployments.

The infrastructure spending required to supply global demand (the infrastructure gap) has been estimated at US$3.7 trillion annually worldwide. Considering this demand and the vast amount of social and environmental capital invested in closing the gap, it is especially important to create more sustainable infrastructure projects. In order to define the criteria to be applied, it is crucial to answer questions such as: (i) What are the best practices to apply in a project for a more sustainable outcome? (ii) What is the current state of sustainability integration in infrastructure projects? To narrow the scope, this research will focus on the Latin American and Caribbean (LAC) region, and will be framed by the initiative of the Infrastructure 360 Awards. This initiative was promoted by a partnership of the Inter-American Development Bank and Harvard University to identify, evaluate, and reward sustainable practices implemented in infrastructure projects developed in the LAC region. This initiative provides an unparalleled body of knowledge by the uniform application of the same methodology (the Envision rating system) to a total of 38 projects, making it possible to draw conclusions about the current sustainability performance of an infrastructure project and opportunities for improvement. To participate in the Infrastructure 360 Awards initiative, projects had to be privately funded, with a budget of more than US$30 million, and had to be in a current phase of construction during the year of the award or recently completed. The Envision rating system data on these projects was used to test the following hypotheses: (1) larger-scale infrastructure projects in Latin America have incorporated better practices than smaller-scale projects; (2) projects located in more developed countries have stronger regulatory frameworks in social and environmental requirements and therefore more sustainable outcomes; (3) projects financed by multilaterals, such as the World Bank, Investment Financial Institution (IFC) or the Inter-American Development Bank (IDB), will have more sustainable practices, and score higher in the assessment, than projects financed by other sources; and (4) project typology plays an important role in determining the sustainability outcome of the projects. To test these hypotheses, a statistical analysis was conducted using R3.3.1 software, as well as spreadsheet analysis. According to the statistical analysis, and taking an alpha level of 0.05, the project typology- hypothesis 4- was statistically significant. The other three hypotheses would require a larger sample size of 139 projects to achieve enough explanatory power to reject or fail to reject the null hypothesis testing 64.30% of the possible variables correlations. The spreadsheet analysis conducted took two different views: (i) analysis by Envision category and (ii) analysis by project typology. This showed that project leadership is a key matter to ensure high sustainability, that projects have low scores in issues related to infrastructure resiliency, and that water and waste projects have overall high performance vs. transportation or energy ones. Besides advancing the state of knowledge in the field of infrastructure sustainability, this research also provides a framework of preferable practices to be applied for decision makers, developers or policymakers for improving the sustainability performance of infrastructure projects.

Solar power is becoming increasingly important as a source of energy in the United States. While solar represents a low-emission source of energy, integrating it into the electrical grid is challenging. The power output of solar is not controlled by operators, but is instead determined by the weather. Since solar power is not able to be controlled as a typical power station would be, analyzing its behavior is essential. This paper looks at three main points: the significance of short term variability in solar power output, mitigation techniques for short term variability, and how solar resources could change over the 21st century. New England is the geographical focus of the analysis of short term variability as well as the geographical focus of the mitigation analysis. This region was chosen because its climate makes it especially susceptible to short term variability. Additionally, its solar industry is already being affected by policy decisions where short term variability plays a role. This study found that short term variability of solar photovoltaic arrays was significant in both magnitude and frequency. Over the course of a year, panels could be expected to fluctuate over 95% of their rated power output in a 5 minute time interval. Additionally, a strong seasonal correlation was found with short term variability. Variability reached a minimum in the winter, while peaking in the late spring and early autumn. The mitigation analysis found that the addition of a storage system could effectively moderate the effects of short term variability produced by solar panels. The driving factor of the effectiveness of the storage system in mitigating variability was its maximum power output. The Southwestern United States is the focus for the analysis on how solar resources may change in the 21st century. This region was chosen because it currently has the best solar resources in the US, which may lead to expensive and long-lasting infrastructure being installed in the area. Thus, the projected climate of the region becomes important. This study finds that solar resources in the Southwestern United States are projected to remain relatively steady over the coming century. The quality of the solar resources in the Southwest is expected to be maintained even under a medium or high carbon dioxide emissions scenario. Interestingly, the average cloudiness of the region is expected to increase with no effect on the amount of solar radiation the region receives.

The CleaN waTer filtration device strives to effectively and efficiently remove 100% of bacteria from water using solar power. Access to clean water is a common problem for communities throughout the world. Many of these communities also struggle to overcome poverty, low education, and minimal access to electricity. Manchay, Peru is one of these many communities. The quality of water in Manchay is unknown, and the only effective method of water treatment in the area is boiling. The development of a robust and easy to use water filtration system that does not require electrical infrastructure has the potential to provide such a community with a reliable source of clean water. The CleaN waTer device outputs clean water after the input of contaminated water and solar radiation. The solar power is stored in a battery. The stored energy powers a pump that propels water through an electrochemical filter. The electrochemical filter uses multiwalled carbon nanotubes (MWNTs) to deactivate and sieve the bacteria. This system outputs one liter of water in 25 minutes and can output up to 6.5 liters of water after one charge. The device was evaluated by measuring the levels of Escherichia coli (E.coli) in the effluent water. Water treated with the device passes the EPA regulations for potable water. Due to the intuitive nature of the CleaN waTer filtration device, it could revolutionize water treatment in Manchay and impact other communities around the world.

Organic and microbial fouling are the initial steps for biofilm formation, resulting in severe fouling problems in many environmental and engineered applications including membrane water filtration. Electro-active methods are proposed to mitigate microbial as well as organic fouling via electrokinetic and/or electrochemical mechanisms. In the first part of this thesis, a parallel-electrode configuration was adopted and the cathode antifouling was evaluated. A carbon nanotube-polyvinylidene fluoride (CNT-PVDF) porous non-Faradaic cathode was first fabricated on top of an ultrafiltration (UF) membrane to produce negative surface charges via capacitive charging at 2 V, which reduced energy requirements (up to 2-fold) in comparison to the unmodified control. A semi-quantitative study was then completed on cathode coatings of different nanomaterials (CNM) to reduce microbial fouling. The bacterial attachment and inactivation were correlated to the electric potential and cathodic H2O2 generation, respectively. Next, a CNT and carbon black (CB) composite cathode was made on a forward osmosis (FO) membrane surface and challenged with synthetic and actual wastewater, which reduced fouling in regard to initial flux loss (~60%) for the actual wastewater and fouling rate (~50%) for both solutions at 2 V in 84 h. In the other part of the thesis, the electrode configuration was improved by fabricating interlaced surface electrodes on a substrate or membrane surface instead of only using a cathode. Insulated interlaced Ag electrodes resulted in optimal bacterial inactivation (84%) and detachment (94% after 15 h biofilm growth) with 2 min treatment at 50 V AC (10 kHz). Interlaced CNT electrodes on a microfiltration (MF) membrane altered the bacterial density and morphology at 2 V DC and reduced the fouling rate by up to 75% under the optimal filtration conditions at 2 V AC.

The United Nations estimates that the growing human population will reach approximately 9.6 billion by 2050. In order to accommodate the subsequently higher demand for food and related strain on resources, careful consideration of diet choice will be essential. This research evaluates the impact on greenhouse gas emissions from three different diets: vegan, vegetarian, and meat-based. This research is important is because greenhouse gas emissions from food are estimated at around 17% of total emissions. This study measures and evaluates all the steps in the food supply chain related to food production under conditions as they exist in the United States, using the Houston, Texas area as a base for the study. The intent of this research is to increase awareness of the global warming consequences of dietary food choices. My initial expected results—that vegan diets have the least emissions impact and meat-based diets have the highest—were confirmed via life cycle analysis. In this case study, vegan diets had a minimum contribution of 809 kg per person per year, followed closely by the vegetarian diet with 957 kg per person per year. However, a far higher greenhouse gas emission of 2,880 kg per person per year was calculated from the meat-based diet. The data from this study should help guide future food production decisions while also addressing the need for a reduction of greenhouse gas emissions through alternative food choices.

Providing secure and reliable water supply service to major urban areas has become a considerable challenge in recent years on a global basis. Rapid population growth, urbanization and development needs put enormous pressure on water resource managers to satisfy the ever-growing demand. Climate change, in addition to the inherent variability in hydrological cycles, adds another layer of deep uncertainty to forecast surface water availability. Many major cities have observed declining reservoir storages during unprecedented droughts. The once-reliable reservoir storage systems can no longer serve its purpose. During extended period of water shortages, urban residents and businesses suffered from mandatory water restrictions, causing large economic and social welfare losses. Facing these challenges, water utilities and governments make large investments in supply augmentation infrastructure, which have long-term consequences that can shape development for decades. However, the increasing complexity of uncertainty suggests that the ability to predict the future is limited; hence, there is a need to shift from the conventional “predict-then-act” planning paradigm. This thesis presents an alternative framework to urban water investment planning, using a portfolio approach. A generalized risk-based framework for urban water supply-demand planning is proposed, and it is applied to Melbourne, Australia, to demonstrate its utility and usefulness. First of all, water shortage risk is clearly defined in two terms–frequency and severity of water shortages–of a defined planning horizon. Supply-side uncertainty is quantified based on probability distributions of precipitation and runoff to reservoirs. Demand-side uncertainty is modeled by scenarios with different combinations of population growth rate and per capita water usage. Next, the thesis presents an investment decision-making tool to identify cost-effective supply-demand portfolios that minimize water shortage severity while achieving a target level of reliable service. In addition to find the optimal portfolio composition, the model presents sequences of investments, indicating timing of implementation of each chosen measure. Using mixed integer programming, the decision-making tool yields Pareto efficient frontiers for different demand scenarios. The Pareto frontier exhibits trade-offs between cost of a water supply-demand strategy and water shortage risks facing a society in the long run. The trade-offs provide analytical insights on risk attitude towards water supply services, namely (i) what is the acceptable level of water shortage risk for a society, and (ii) how much are customers willing to pay to avoid such a risk. The results indicate that a portfolio which diversity risk of individual supply augmentation and conservation measures is robust when confronting a wide range of plausible climate and demand growth scenarios. Finally, recognizing important roles played by society and government in water-related investment decision-making process, the thesis discusses institutional barriers in adopting and implementing the proposed risk-based framework in practice. This thesis presents an alternative framework to quantitatively integrate risk in urban water resources management. Under this framework, the portfolio approach is an analytical tool for decision-makers to prioritize investments in supply augmentation infrastructure and implementation of demand management programs. It is the hope of the author that this work provides new insights and necessary tools to water sector professionals in urban water investment planning. The use of risk-based framework and portfolio approach is not limited to any specific city and could find many applications in urban areas where water scarcity and climate risk are pressing issues.

This study investigates the long-term thermal performance of polyurethane insulated cold storage panels and the environmental and economic impact of recycling such panels when taken out of service in lieu of discarding them in landfills. It is estimated, as of 2015, over 180 million square feet of insulated cold storage panels are manufactured annually in the U.S. The panels are most frequently constructed of closed-cell, low density polyurethane insulation utilizing HCF 245fa and HCF 134a blowing agents containing up to 6 million metric tons (CO2e) of greenhouse gases. The expected operating lifetime of the cold storage panels is 15 years after which time they are primarily discarded in landfills. This practice contributes to the build-up of greenhouse gases in the atmosphere, destroys valuable insulating and building materials and requires landfill space for the solid waste. Three recycling strategies were investigated as ways to repurpose the discarded framed cold storage panels into new forms of polyurethane insulating materials; repurposed cold storage panels, board stock insulation sheets and blown-in/fill insulation. I used three research methods to quantify the environmental and economic impacts. The first examined the initial and long-term thermal performance of the recycled polyurethane insulation through laboratory testing and extrapolative modeling. The second method was comparative life cycle assessments between the business-as-usual-case of discarding the polyurethane insulation with each of the recycled strategies. Finally, an economic analysis was completed for each recycling strategy to determine the in-use heating & cooling energy savings from the extended life of the recycled insulation. This research shows recycling of discarded polyurethane cold storage panels provide measurable environmental and economic benefit. First, the productive life of the insulation is extended greatly beyond its initial use period reducing the need for fossil fuels and raw materials to make replacement insulations. Secondly, the high insulating value of the recycled polyurethane maximizes future environmental and economic savings from lower fuel demand in space heating and cooling applications. Thirdly, the majority of the sequestered greenhouse gases continue to be bound in the foam; protecting the environment from the release of global warming gases. Finally, by diverting the cold storage panels from landfills, millions of cubic feet of landfill space are unneeded annually.

The physicochemical properties of the secondary organic materials (SOMs) that constitute the particle phase have potentially important consequences for the growth, the reactivity, and ultimate fate of atmospheric organic aerosols, thereby affect climate, human health and visibility. A quantitative analysis of the physicochemical properties of the SOMs is important, but challenging. This thesis presents laboratory studies of α-pinene derived SOMs, which is one of the major components of secondary organic aerosols (SOAs) in the forests, by combing a flow tube reactor, aerosol particle mass analyzer (APM) and other online/offline measurement techniques. A water-jacketed constant temperature flow tube reactor was built to produce SOM particles grown from either condensation or coagulation. Different ratios of α-pinene enantiomers were mixed and injected into the flow tube reactor for dark ozonolysis. A matrix of organic precursor and ozone concentrations was designed and tested in order to determine the optimal concentration to switch between condensation and coagulation. Results show that at 51 ± 1 ppm O3, condensation is the dominant growth mechanism when the α-pinene concentration is 0.125 ± 0.001 ppm, and coagulation is the dominant growth mechanism when the α-pinene concentration increases to 1.00 ± 0.03 ppm. A combination of both growth mechanisms is observed when the α-pinene concentration is in between the described values. The study also proposed and tested the hypothesis that a 50:50 mixture of α-pinene enantiomers may result in SOM particles that have different physical properties, such as number-diameter distributions, when compared with those particles generated from a single enantiomer of α-pinene. The experiment was conducted within the condensational growth regime so that the chirality induced structure differences in oligomers can be maximized during the nucleation and condensation. Nevertheless, our analysis indicates that, after removing the effects of ozone and temperature, the chirality-induced effects are minimal and within our detection limit. Even though the results were negative, the method used in this experiment provided useful experience for the viscosity related experiments in this thesis. Another important property of the SOM is its viscosity. The viscosities of atmospheric particles determine whether their interactions with surrounding gases are confined to the surface or can proceed to the interior. Viscosities affect the gas-particle diffusion rate, and ultimately influences the SOM’s other physical properties, such as particle size, and chemical properties, such as reactivity. The work presented in this thesis estimates the viscosity of submicron organic particles while they are still suspended as an aerosol without further post-processing techniques that can have the possibility of altering the properties of semivolatile materials. The results show that the studied particles are semisolid up to 58% relative humidity (RH) and may become liquid only at a higher RH. These results imply that atmospheric particles, at least those similar to the ones studied and for low to middle RH regimes, are expected to reach equilibrium only rather slowly with the chemical composition of the gas phase, sometimes on timescales longer than the actual residence time of the particles in the atmosphere. Last but not the least, the results of offline particle analysis from two collaboration studies are also discussed in this thesis. The results show how water vapor, or RH, affects the physicochemical properties of the α-pinene derived SOM particles. In one study, the diffusivity is underestimated by approximately 8 orders of magnitude if calculated from the Stokes-Einstein equation, which suggests the breakdown of Stokes-Einstein equation for small gas molecules. The second study shows the surface properties of SOM particles can be influenced by the RH, leading to a difference of the gas-particle interactions at the particle surface.

Greenhouse gas emission magnitudes, trends, and source contributions are highly uncertain, particularly at sub-national scales. As the world becomes increasingly urbanized, one potential strategy for reducing these uncertainties is to focus atmospheric greenhouse gas measurements in urban areas, where a multitude of emission processes occur, imposing a strong and persistent gradient in the local atmosphere, and contributing a significant fraction of global anthropogenic greenhouse gas emissions. This thesis explores the capabilities and requirements for characterizing and quantifying greenhouse gas fluxes in urban environments using atmospheric measurements and models. The first chapter uses an existing dataset of atmospheric carbon dioxide measurements from Salt Lake City, Utah to assess the capacity of an atmospheric measurement and modeling framework to detect changes in emissions from a city in the context of an emissions verification framework. The results of this work are then used to explore an alternative or complementary measurement strategy of atmospheric column measurements for urban emissions detection, which would be less sensitive than point measurements to the large variability present in urban atmospheres, but would also have more stringent accuracy requirements. The second chapter describes the development and maintenance of a network of greenhouse gas measurement stations in the Boston urban region, which has been continuously running since 2012 and has generated high-quality atmospheric carbon dioxide and methane data that can be used to explore their fluxes across the urban region. The third chapter applies the Boston network data to investigate the magnitude of methane emissions from natural gas infrastructure in the urban region. We find that the natural gas loss rate in 2012-13 was 2.7 ± 0.6 %, two to three times larger than that reported by industry and government. Our findings suggest that natural gas consuming regions may be larger sources of methane than previously thought, and have implications for local and national policies that aim to reduce methane emissions and promote energy-use efficiency. The work presented in this thesis explores general methodological strategies for urban atmospheric measurements and models, and offers example applications of such methods to directed and societally-relevant investigations of urban greenhouse gas emissions.

Water treatment is a critical global challenge requires innovated effective solution. Conventional treatment methods includes membrane filtration, adsorption and electrochemical oxidation of organics. This dissertation proposed a new hybrid of the three conventional technologies and investigated the mechanism and application potential for water treatment using carbon nanotube (CNT) based anodic filter. A qualitative reactive transport model consisting of mass transport, adsorption/desorption, electron transfer was developed to understand reaction mechanism and compare the filtration with the batch electrochemical system. The mass transport step is found to be the key advantage (>6-fold) of the electrochemical filtration over the batch system due to convective mass transport through the filter pores. This indicate synergy between the filtration and the electrochemisty. A quantitative model coupling the above three steps was also build to quantitatively simulate the reaction kinetics and probe information about reactive sites. The model simulation was successfully validated by experimental methyl orange oxidation data and was further used to identify kinetics from reactive sites. It was found that two types of reactive sites–the sidewall sites and oxy-defect sits are both reactive for ferrocyanide oxidation with a slightly different overpotential. Also, microscopic flux and steamline plot again verify the convective mass transport enhance reaction kinetics–synergy of the filtration and electrochemistry. To improve potential for organic oxidation applications, the CNT filter was coated with 3.9±1.5 nm bismuth-doped tin oxide (BTO) nanoparticles. In the oxalate oxidation experiments, the current efficiency increased by 1.5–3.5 times and TOC removal increased by 2–8 times after coating. The BTO-CNT anode energy consumption was 25.7 kWh kgCOD-1 at ~93% TOC removal and 8.6 kWh kgCOD-1 at ~50% TOC removal, comparable to state-of-the-art oxalate oxidation processes (22.5–81.7 kWh kgCOD-1). The anode stability also improved by extending the working potential range from 1.4 V of pure CNT to 2.2 V of BTO coated CNT. For inorganic ion removal applications, the CNT filter was coated by a 5.5 ± 2.7 nm layer of TiO2 for arsenic removal. Compared with the conventional adsorption column using granular adsorbents, the TiO2-CNT filter is a highly dispersed nano-system allows forced convective transport through the pores whereas diffusive mass transport dominates and limits kinetics for granular adsorbents. As a result, adsorption kinetics of the TiO2-CNT filter increased by two orders of magnitude due to structure improved site accessibility (20–30 fold), internal convection (4–6 fold) and electrosorption (0.15–2 fold). Groundwater samples containing 44 ppb As were treated by single-pass filtration, and 12500 bed volumes (residence time of 4.5 s; 127 L m-2 h-1; 5.8 mg m-2 h-1). TiO2 filter was successfully regenerated by 5 mM NaOH for both As(III) and As(V).

Under anaerobic conditions, it is widely assumed that nitrate (NO3-) and nitrite (NO2-) reduction is primarily the result of microbial respiration (Burgin and Hamilton, 2007; Granger et al., 2008). However, it is also proven that the abiotic reduction of nitrate and nitrite by reduced iron(II) (Fe(II)), whether mineral-bound or surface-associated, may also occur under certain environmentally relevant conditions (Chao and Kroontje, 1966; Straub et al., 1996; Picardal, 2012,). With a range of experimental conditions, nitrogen and oxygen stable isotope systematics of abiotic nitrite reduction by Fe(II) were investigated in an effort to characterize the biotic and abiotic processes in the environment. While homogenous reactions between NO2- and Fe(II) in artificial seawater (ASW) showed little reduction, heterogeneous reactions involving Fe-containing minerals showed considerable nitrite loss. Specifically, rapid nitrite reduction was observed in experiments that included reduced nontronite clay and an Fe(II)-Fe(III) hydroxide mineral, termed green rust. These iron oxides and clay minerals offer both a source of reduced iron in the mineral matrix as well as a surface for Fe(II) activation. Additional control experiments with corundum as a non-Fe containing mineral surface showed little NO2- loss, implicating a more dominant role of structural iron in the clays during nitrite reduction. In experiments with nontronite and green rust the isotope effects (15ε and 18ε) ranged from 3 to 16‰ for 15ε and 2 to 6‰ for 18ε. Nitrite reduction rates and 15ε values within an experimental condition were directly correlated with slower reactions having higher isotopic fractionation. The apparent 18ε was affected by oxygen atom exchange with water, which lowered the isotope effect. Although little data exist for comparison with the dual isotopes of microbial NO2- reduction, these data serve as a benchmark for evaluating the role of abiotic processes in nitrogen (N) reduction, particularly in sediment systems low in organic carbon and high in reduced iron.

First order trends in the strontium isotopic (87Sr/86Sr) composition of seawater are controlled by radiogenic inputs from the continent and non-radiogenic inputs from exchange at mid-ocean ridges. Carbonates precipitated in seawater preserve trace amounts of strontium that record this isotope ratio and therefore record the relative importance of mid-ocean ridge and weathering chemical inputs to sea water composition. It has been proposed that environmental changes during the Ediacaran-Cambrian transition may have enabled the rapid diversification of life commonly named the “Cambrian explosion.” Proposed environmental changes include 2.5x increase in mid-ocean ridge spreading at the Ediacaran-Cambrian boundary and large continental fluxes sediment into oceans. These hypotheses rely on a poorly resolved strontium isotope curve to interpret Ediacran-Cambrian seawater chemistry. A refined strontium isotope curve through this time period may offer insight into the environmental conditions of the early Cambrian. New age models and detailed mapping in the Zavkhan terrane in west-central Mongolia provide the context necessary for robust geochemical analysis. This study aims to better resolve the coarse strontium isotope curve for the early Cambrian period by analyzing carbonate sequences in the Zavkhan basin. These carbonate sections are rapidly deposited, have undergone little diagenesis, and are likely to preserve a primary seawater signal. Strontium isotope analysis of these sequences was carried out to determine changes in hydrothermal activity and weathering fluxes during this time period. Recompiling these data with a global dataset of strontium isotopes through this time period indicates a stable strontium isotope signal through much of the early Cambrian. These data do not support previous hypotheses attributing the driving mechanism for the early Cambrian transition from Mg-dominated to Ca-dominated seas to increased sea floor spreading rates.

Photooxidation of isoprene has a large influence on the oxidation capacity of the atmosphere and is a significant source of secondary organic material (SOM) of atmospheric particles. A quantitative understanding of isoprene photooxidation mechanism, in particular in the clean atmosphere, is important but challenging. This thesis presents laboratory and field studies of isoprene photooxidation via the hydroperoxyl (HO2) pathway, believed to be the most important reaction pathway of isoprene-derived peroxy radicals under clean conditions, by using a switchable-reagent-ion (NO+; H3O+) time-of-flight mass spectrometer (SRI-TOF-MS). Isoprene photooxidation via the HO2 pathway was investigated in a continuous-flow chamber. Production yields of methyl vinyl ketone (MVK) and methacrolein (MACR) pathway were determined as (3.8 ± 1.3)% and (2.5 ± 0.9)%, respectively, at

The Gulf of St. Lawrence Aster (Symphyotrichum laurentianum ) (SLA) is an annual plant species endemic to the Gulf of St. Lawrence region. Due to the dynamic nature of the environment that the Gulf of St. Lawrence Aster inhabits, severe and major threats to both the Aster and its habitat exist. The Committee on the Status of Endangered Wildlife in Canada listed the species as Threatened in Canada in 2004. This status was reached due to the species' limited distribution, fluctuating population size, and to continued pressures on its habitat. Surveys have revealed that both site and population numbers have been further and drastically reduced on Prince Edward Island. In 2007 only one populated site remained with a low number of 482 individuals. It is possible that this species is on the brink of extirpation from PEI.

Trichloroethene (TCE) is a persistent soil and groundwater pollutant that is known to be toxic to humans. Ex situ treatment is currently considered the most viable option for remediation of TCE contaminated sites. Among ex situ techniques, soil vapor extraction (SVE) and dual-phase extraction (DPE) with air sparging are more attractive since they result in rapid remediation of sites. However, waste gas streams laden with TCE are thus generated, and these require treatment. While traditionally this has been done using incineration or adsorption onto activated carbon, in this dissertation it is proposed that treatment of waste gases containing TCE can be carried out in anaerobic biological reactors, after displacement of oxygen during SVE or DPE with nitrogen. These anaerobic bioreactors rely on the metabolism of novel microorganisms from the Dehalococcoides genus that reductively dechlorinate TCE all the way to non-toxic ethene via cis-1,2,-dichloroethene (cis-DCE) and vinyl chloride (VC), in combination with oxidation of hydrogen.For providing the proof of concept of anaerobic TCE waste gas treatment, a lab-scale anaerobic biotrickling filter inoculated with a mixed culture containing Dehalococcoides spp. that harbor the TceA and VcrA reductive dehalogenases was setup and monitored for performance. A biotrickling filter configuration was chosen since it gives an easy means of providing lactate as an indirect source of hydrogen to Dehalococcoides spp. immobilized on the bed packing through its fermentation. TCE elimination capacities (EC) higher than those reported for aerobic gas-phase bioreactors treating TCE were observed. The distribution of the intermediates of TCE dechlorination was significantly affected by the recirculating liquid pH, with near neutral pHs resulting in the maximum conversion of removed TCE to ethene (>60% at loadings of 3 gTCE mbed-3 h-1). Because complete conversion to ethene was not observed, a detailed modeling study followed focusing on the determination of biokinetic constants for the dechlorination of TCE, cis-DCE and VC as well as any inhibition that may exist between these compounds. Dechlorination data from experiments with differential reactor operation with single compounds only were fitted to the model to determine biokinetic constants. Experiments with multiple compounds were used to determine inhibition between various compounds. It was found that the Michaelis-Menten constants for all compounds were higher than when grown typically in suspended cultures (i.e. lower enzyme affinity). It was also observed that TCE competitively inhibits the dechlorination of cis-DCE, and also has an effect on the dechlorination of VC, suggesting that some modification to the process culture could alter the distribution of the intermediates. To test the hypothesis that addition of a strain containing a different reductive dehalogenase (BvcA, responsible for dechlorination of cis-DCE and VC) could result in better conversion of TCE to ethene, a biotrickling filter inoculated with the original culture used and operating at high loads (8-9 gTCE mbed-3 h-1), was bioaugmented with Dehalococcoides sp. strain BAV1 that contains the BvcA enzyme. It was found that conversion of TCE to ethene was improved significantly (from

Human pathogens have been observed in municipal drinking water systems. Microbial intrusions due to distribution system deficiencies are a recognized cause of acute gastrointestinal illness (AGI) outbreaks. Yet, their importance as a cause of sporadic and endemic AGI is poorly understood. The WAHTER (Water And Health Trial for Enteric Risk) study sought to characterize health impacts associated with virus intrusions into drinking water distribution systems, as well as with virus contamination of source groundwater. The WAHTER study was designed as a cohort epidemiological trial with cross-over intervention, taking place in 14 small Wisconsin communities relying on untreated groundwater. Six human enteric virus types were enumerated by RT-qPCR in the source groundwater and household tap water of the study communities during four three-month periods in 2006-2007. AGI incidence in the communities was reported through weekly health questionnaires. Each community received intervention in the form of UV disinfection at active wellheads for one of the study years. During UV intervention viral contamination in source groundwater was virtually eliminated, so that viruses detected at taps could be ascribed to intrusions into distribution systems. Within the context of the WAHTER study, this dissertation focuses on: the validation of a method to concentrate viruses from water using glass wool filtration (Chapter 1); a method to estimate virus numbers in environmental samples using integrated cell culture-qPCR (Chapter 2); the association between distribution system maintenance or failure events and viral contamination in distribution systems (Chapter 3); and estimating non-epidemic AGI incidence associated with virus intrusions into distribution systems (Chapter 4). The association between virus levels at household taps and distribution system events was tested using generalized linear regression. The occurrence of pipe installations was significantly associated with increased virus levels in distribution systems, while hydrant flushing was significantly associated with reduced virus loads (Chapter 3).AGI associated with distribution systems was estimated using a Monte Carlo-based static risk assessment framework. Results suggest that virus intrusions into drinking water distribution systems can be a significant contributor to non-epidemic AGI. Distribution system risk was highly variable, reflecting the sporadic nature of contamination events (Chapter 4).

Mesoscale models, such as the Weather Research and Forecasting (WRF) model, are increasingly used for high resolution simulations, particularly in complex terrain, but errors associated with terrain-following coordinates degrade the accuracy of the solution. Use of an alternative Cartesian gridding technique, known as an immersed boundary method (IBM), alleviates coordinate transformation errors and eliminates restrictions on terrain slope which currently limit mesoscale models to slowly varying terrain. In this dissertation, an immersed boundary method is developed for use in numerical weather prediction. Use of the method facilitates explicit resolution of complex terrain, even urban terrain, in the WRF mesoscale model. First, the errors that arise in the WRF model when complex terrain is present are presented. This is accomplished using a scalar advection test case, and comparing the numerical solution to the analytical solution. Results are presented for different orders of advection schemes, grid resolutions and aspect ratios, as well as various degrees of terrain slope. For comparison, results from the same simulation are presented using the IBM.Both two-dimensional and three-dimensional immersed boundary methods are then described, along with details that are specific to the implementation of IBM in the WRF code. Our IBM is capable of imposing both Dirichlet and Neumann boundary conditions. Additionally, a method for coupling atmospheric physics parameterizations at the immersed boundary is presented, making IB methods much more functional in the context of numerical weather prediction models. The two-dimensional IB method is verified through comparisons of solutions for gentle terrain slopes when using IBM and terrain-following grids. The canonical case of flow over a Witch of Agnesi hill provides validation of the basic no-slip and zero gradient boundary conditions. Specified diurnal heating in a valley, producing anabatic winds, is used to validate the use of flux (non-zero) boundary conditions. This anabatic flow set-up is further coupled to atmospheric physics parameterizations, which calculate surface fluxes, demonstrating that the IBM can be coupled to various land-surface parameterizations in atmospheric models.Additionally, the IB method is extended to three dimensions, using both trilinear and inverse distance weighted interpolations. Results are presented for geostrophic flow over a three-dimensional hill. It is found that while the IB method using trilinear interpolation works well for simple three-dimensional geometries, a more flexible and robust method is needed for extremely complex geometries, as found in three-dimensional urban environments. A second, more flexible, immersed boundary method is devised using inverse distance weighting, and results are compared to the first IBM approach. Additionally, the functionality to nest a domain with resolved complex geometry inside of a parent domain without resolved complex geometry is described. The new IBM approach is used to model urban terrain from Oklahoma City in a one-way nested configuration, where lateral boundary conditions are provided by the parent domain.Finally, the IB method is extended to include wall model parameterizations for rough surfaces. Two possible implementations are presented, one which uses the log law to reconstruct velocities exterior to the solid domain, and one which reconstructs shear stress at the immersed boundary, rather than velocity. These methods are tested on the three-dimensional canonical case of neutral atmospheric boundary layer flow over flat terrain.

This dissertation summarizes the results from a study to develop and evaluate models to estimate dispersion of pollutants in boundary layers whose properties change with downwind distance. Such boundary layers occur at the interface between rural and urban areas, and water and land bodies. I first developed a method to estimate the meteorological inputs required to apply the current generation of dispersion models, such as AERMOD, to urban areas. This method uses measurements made at a single level on a tower located in an urban area, and is based on the assumption that similarity methods applicable to spatially homogeneous conditions are locally valid even in an inhomogeneous urban area. I show that under unstable conditions, measurements of temperature fluctuations improve upon commonly used energy balance methods to estimate heat flux. Also, any bias in heat flux estimates has a minor effect on the prediction of surface friction velocity and turbulent velocities. I examined a method to estimate urban micrometeorology using measurements made on a tower located in an upwind suburban area. I applied an internal boundary layer model to trace the evolution of the boundary layer as it traveled from the suburban measurement location to the urban location of interest. Estimates from the model were observations made during a field study conducted in Riverside, CA. Estimates of friction velocity compare well with urban measurements only when the variation of friction velocity with height within the urban canopy was accounted for. I examined the performance of two steady-state dispersion models in explaining concentrations measured during field studies designed to study low wind speed conditions typical of urban areas. One model is based on the numerical solution of the two-dimensional mass conservation equation and the other is AERMOD, which accounts for low wind speeds by including wind meandering. The numerical method performs better than AERMOD through a justifiable description of the interaction between dispersion and the gradient of the wind speed near the surface. Including wind meandering, which occurs under low wind speeds, improves the performance of the numerical model. As part of this study, I developed a method to improve estimates of surface friction velocity during low wind speeds. The last model is applicable to elevated sources, such as power plants, situated close to shorelines. It is designed to be compatible with AERMOD (Cimorelli et al., 2005), the USEPA's regulatory model that is currently designed for spatially homogenous conditions. The semi-empirical shoreline dispersion model accounts for plume entrainment by the thermal internal boundary Layer (TIBL), whose height increases with distance from the shoreline. I show that AERMOD can be modified to account for two-dimensional shoreline effects, and this modified model performs as well in explaining observations as dispersion models specifically designed for shoreline sources. I also developed a method to generate meteorological inputs that are compatible with the current structure of AERMOD's inputs.

Waterborne transmitted viruses pose a public health threat due to their stability in aquatic environments and their ease of transmission with high morbidity rates at low infectious doses. The ability to detect infectious viruses is of critical importance for environmental health and safety. Current methods to assess the presence of infectious viruses are based on detecting the production of cytopathic effects from mammalian cell culture and can take up to weeks before positive identification. Improved methods for rapid and reliable detection and population quantification of infectious viruses are needed for public health assessments. Molecular beacons (MBs), which produce fluorescence upon target binding, provide a simple and separation-free scheme for rapid and sensitive detection of infectious viruses. However, for real-time studies in living cells, the durability of MBs is affected by the intracellular nuclease degradation. Additionally, cell fixation and permeabilization are required to maintain the cellular structure before introducing MBs. In this study, we developed several FRET (fluorescence resonance energy transfer)-based MBs combined with fluorescence microscopy to directly visualize the fluorescent hybrids with newly synthesized viral RNA as an indication of viral infection and to subsequently follow virus spread among cells in situ/in vivo. To prevent nucleolytic degradation, we designed MBs containing 2'-O-methyl RNA bases with phosphorothioate internucleotide linkages, which specifically target the 5' noncoding region of the viral genome. A cell-penetrating Tat peptide was appended to the FRET probes to facilitate non-invasive entry into host cells. To further improve the probe sensitivity in providing real-time and long-term detection of viral replication, MBs composed of quantum dot and gold nanoparticles were generated. Confluent cell monolayers were incubated with the probes followed by infection with virus dilutions and the fluorescence intensity was monitored in real time. Sensitivity experiments showed that 1 PFU detection limit could be achieved within one replicative cycle. The illumination of fluorescent cells increased in a dose-responsive manner and enabled the direct quantification of infectious viral doses. By introducing the modified MBs into the host cell population prior to viral infection and tracking the change of fluorescence signals, we observed cell-to-cell spread when progeny virions infected new host cells in which the infectious cycle could be repeated. The specific nature of these probes enable their utility for rapid diagnostics of viral infections and real-time viral detection in vivo provides sufficient information regarding multiple steps in infection processes at the subcellular level, which will be valuable for the prevention, control, and understanding of viral infection.

Soil salinity levels are an important determinant of plant evapotranspiration and carbon uptake. In this dissertation I develop, evaluate, and test a model of plant evapotranspiration and carbon uptake in the context of a saline soil environment, and drive the model using leaf physiological parameters determined from field measurements. This modeling work is performed in the context of three research questions: (1) How are leaf gas exchange parameters characterizing photosynthesis in perennial pepperweed best determined for seasonal scale landscape flux analysis? (2) How can the effects of soil salinity on root water uptake be represented in order to account for changes in the diurnal cycle and in the uptake of carbon dioxide by plants? (3) How sensitive are modeled results to changes in model input parameters, and how may these sensitivities limit the predictive abilities of the model? These questions are assessed using data from a relatively wet pasture-peatlands in the San Francisco Bay - Sacrament River Delta region of California, with the dominant land-cover species perennial pepperweed (Lepidium latifolium), a mildly salt-tolerant and invasive herbaceous weed. Presented in this research is a characterization of pepperweed as a highly capable invasive species, able to take advantage of local resources such as light, carbon, water, and nitrogen. Modeling results from each section also demonstrate its ability to photosynthesize under higher temperatures and vapor pressure deficits than standard plant models suggest. Incorporating soil salinity into a whole-plant model increases the ability to describe how different soil and atmospheric parameters influence evapotranspiration and photosynthesis in such an environment. The model's sensitivity analysis reveals two pairs of parameters that may constrain each other, and demonstrates how improved measurements of plant conductance and leaf water potential can constrain other portions of the parameter space.

Microbial and colloidal particle transport and deposition onto solid surfaces are of great significance to many environmental and technological processes. Initial attachment of particles is governed by the interactions between particles and surfaces. Classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory is utilized to predict interactions between particles and surfaces. However, discrepancies between experimental observations and theoretical predictions exist and the failure of the predictive model is often attributed to particle and solid collector physical and chemical heterogeneities.This work sought to elucidate the contribution of heterogeneity to the initial particle deposition behavior in a radial stagnation point flow system or a parallel plate flow chamber system by systematically adjusting particle type and size, as well as collector surface chemical and/or physical properties. In Chapter 2 and 3, the role of particle heterogeneity (type and size) was examined. Comparable deposition trends were observed between particles, in this case groundwater and marine bacteria, Burkholderia cepacia G4g and Halomonas pacifica g, respectively. However, the deposition kinetics of H. pacifica g appeared to be more sensitive to solution chemistry than that of B. cepacia G4g. Experimental results also demonstrated that particle size (colloidal and bacterial) had a considerable impact on the transport and interaction with surfaces. In Chapter 4, a method to influence collector surface charge and subsequent colloid deposition was described. Experimental results suggest colloids respond to local variations in surface potential through electrostatic interactions, altering particle streamlines flowing along the surface, and ultimately the extent of deposition. In Chapter 5, cell deposition onto bare and zeolite coated aluminum alloy and stainless steel surfaces was investigated using bacterium H. pacifica g. Collector surface properties found to have the most notable effect on cell attachment were the electrokinetic and hydrophobic nature of the bare metal and zeolite coated surfaces. In Chapter 6, the relative impact of physical roughness on antifouling nature of zeolite surfaces, as compared to these other chemical mechanisms was investigated.This comprehensive dissertation project established both particle and collector surface heterogeneity has a significant effect on particle deposition, which was clearly identified by altering various physical and chemical interaction parameters between particles and surfaces.

In this dissertation, I explore how life-cycle assessment (LCA) results can potentially be influenced by the location of emissions, also called regionalization. The current practice in life-cycle assessment increasingly stresses the importance of being "geographically differentiated" or "regionalized." Regionalization can be important for cases that have extended supply chains distributed across different regions or for processes situated in locations with environmental conditions and population densities far from "average". A spatially resolved model for North America, called IMPACT North America, is developed here. Geographically differentiated intake fractions and characterization factors are evaluated for the North American continent for human toxicity. Special attention is given to the modeling of intake fractions and characterization factors for particulate matter. These factors can be used to adapt damage-oriented impact assessment methods. Parameters influencing intake fractions and characterization factors are identified, such as population densities and agricultural production. The importance of modeling an "urban box" and a "remote area" is also shown. The case of fly ash concrete is studied through the lens of regionalization, and critical parameters influencing the environmental trade-offs between fly ash concrete and Portland cement concrete are identified.Through the development of the new model, along with the different applications, various questions related to spatial life-cycle assessment can be studied, and several conclusions can be drawn about what is important to consider when performing regionalization in life-cycle assessment.I show that particulate matter dominates damage to human health and therefore the importance of devoting more detailed attention to the character of particulate matter when modeling the fate, exposure and effect of pollutants. I also demonstrate that when addressing the issue of regionalization in inventory and impact assessment, priority should be placed on the development of the archetype-based (i.e., situation-dependent) regionalization; spatialization (geography-based regionalization) should only be used secondarily and in occasional cases when results from key processes need to be expanded.

The fate of pathogens upon excretion to natural environments from initial hosts is not fully understood. Often overlooked is the fact that pathogens either cannot survive or lose their virulent characteristics upon exposure to environmental stress. However, problematic pathogens such as Salmonella are very resilient and acclimate well in secondary habitats; therefore requiring comprehensive studies to understand the mechanisms of fitness and survival in external environments. Additionally, despite the widespread knowledge of Salmonella and its interaction with targeted hosts, the deposition and transport behavior of this important food- and waterborne pathogen is not commonly studied. The objective of this research was to understand the fate and transport of Salmonella under a framework of environmentally relevant groundwater conditions. Therefore several Salmonella enterica serovars with different phenotypes were selected and the depositions of these pathogens onto solid surfaces were examined over a range of solution chemistries. Packed bed column and radial stagnation point flow (RSPF) systems were utilized for the transport experiments. Several batch experiments were designed to simulate the stress conditions in aquatic environments to understand the fate of Salmonella in terms of fitness, survival and virulence. These experiments were complemented by a wide range of cellular characterization techniques. Transport experiments of Salmonella in comparison to another important pathogen, E. coli O157:H7 has shown that Salmonella can be transported further than E. coli in saturated packed bed column systems. Additionally, this transport behavior was shown to be affected by different solution chemistries and cell injection concentrations. Deposition and transport behavior of three Salmonella enterica serovars with different motility phenotypes were studied in packed bed column and RSPF systems. Results have shown that flagellated strains deposit more than nonflagellated strains, concluding that nonmotile cells can be transported further than motile cells. Several batch experiments were designed to simulate a wide range of groundwater conditions to study the fate of Salmonella upon short and long term exposure to environmental stress. Both phenotypical (antibiotic resistance, in vitro and in vivo virulence) and genotypical (gene screening in silico) evaluations of Salmonella fitness, survival, and pathogenicity were conducted. The findings of this research suggest that Salmonella successfully remains viable and virulent under a wide range of groundwater environments.

Fine particulate matter (PM) affects public health, visibility, climate, and influences ecosystem productivity and species diversity. Diesel engines are an important source of air pollution and will face a variety of new regulations, so emissions from these vehicles are expected to undergo changes over the next decade that will have important effects on primary PM emissions, especially black carbon (BC) emissions, as well as nitrogen oxide (NOx) emissions and therefore secondary pollutants such as ozone and PM nitrate. Analysis of observed and modeled air quality responses to changes in diesel engine emissions provides insights into the relative importance of diesel emissions and the effects of future emission controls.Yearlong records of online measurements of black/elemental carbon at Fresno, St. Louis, and Pittsburgh were analyzed as part of this research. Diesel truck activity decreases substantially on weekends, and the pollutant time series were analyzed to look for corresponding reductions in ambient BC concentrations. Significant weekend BC reductions of 22±6 and 25±5% were found at Fresno and St. Louis, respectively. Smaller reductions were observed at Pittsburgh. Continuous measured records of fine particulate nitrate were also analyzed over yearlong periods at the three locations mentioned above and at Claremont, CA, an inland location within the Los Angeles basin. Reductions in PM nitrate were observed on Sundays and Mondays, indicating a delayed response to NOx emission reductions that occur on Saturdays and Sundays. Nitrate reductions of 23±12, 29±23, and 16±9% were observed on Mondays at Fresno, Claremont, and St. Louis, respectively, relative to 7-day moving averages.Exhaust emissions from diesel-powered construction equipment are typically estimated using statistical models. Both the emission estimates and the underlying engine activity estimates are subject to large uncertainties that are not routinely quantified. A fuel-based inventory of construction equipment emissions for California was developed and showed NOx and exhaust PM emissions to be 4.5 and 3.1 times smaller, respectively, than official emission inventory estimates developed by California Air Resources Board staff. Also, a revised description of the spatial distribution of diesel engine activity based on construction permit data showed construction activities had moved on from older housing development projects along the coast to new locations further inland in Southern California. Updating the construction inventory had significant effects on air quality model predictions for NOx, BC, and ozone.A gridded Eulerian model was used to assess weekend effects on particulate matter and compare model predictions weekly nitrate cycles to the observational analysis described above. The model incorporated the new construction inventories described above. This model was further employed to analyze the air quality effects of new regulations on in-use diesel trucks.The model was run over two seasons, and a baseline scenario was compared to a scenario including weekday emissions substituted for weekend emissions. The model analysis showed similar weekend reductions of BC to changes at ground-based observation sites in southern California. Unlike BC, particulate nitrate is a secondary pollutant with non-linear and non- intuitive dependence on precursor emissions. Analysis of particulate nitrate effects was also challenging because observed weekend effects were smaller than for BC, and meteorological variability made the signal harder to discern. Both modeled and observed reductions in nitrate were found on summer Mondays at Claremont (inland site). Process analysis showed that in some locations weekend NOx reductions could lead to higher nitric acid production and higher nitrate levels, as there are factors that offset the effect of lower weekend NOx on the rates of both daytime (OH+NO2) and nighttime (via N2O5) pathways to nitric acid formation. An important difference between modeled nitrate and observed nitrate was found during the fall season: modeled nitrate increased on Monday.The effects on future air quality of new regulations requiring the retrofit of in-use heavy-duty diesel trucks and buses to meet stringent PM emission requirements were evaluated. By 2014, the in-use retrofit rule is predicted to reduce average ambient BC concentrations in southern California by 12±2 and 14±2% during the summer and fall, respectively, relative to a baseline scenario that included emission decreases due to fleet turnover effects but no retrofits. Primary NO2 emissions are predicted to increase with greater use of oxidative particle filters, however, ambient NO2 concentrations are not predicted to increase as parallel, but less stringent, retrofit requirements reduce total NOx emissions. Increases in ambient ozone and particulate nitrate concentrations were predicted to occur within the Los Angeles basin, especially during the fall season, due to an increase in the NO2/NOx emission fraction and reduced total NOx emissions.

This research used a surrogate organism, Bacillus globigii, to better understand the response of a corroded concrete distribution system containing an established biofilm to different chlorine concentrations following a bioterrorism event. Biofilm was cultivated on concrete coated slides in a biofilm annular reactor using microorganisms found in Cincinnati, OH tap water. After one month of accumulation, biofilm HPC values of approximately 6.0 x 103 CFU/cm2 were measured on the slides. Three phases of experimentation were conducted. The first phase of experimentation examined the persistence of adhered and planktonic spores in the absence of a chlorine residual, while the second and third phases were identical and examined spore persistence with different chlorine concentrations. The experimental target concentrations were 1 and 5 mg/l in reactors 1 and 2, respectively.During the first phase, 0.1 ml of 109 cells/ml spore suspension was injected into both reactors. Spore counts of 250-300 CFU/cm2 were seen initially on the slides, and by 225 hours a steady state existence of approximately 125 CFU/cm2 developed in both reactors. Initial spore counts in the bulk water dropped more than 2 logs within 12 hours, but average counts of 185 and 95 CFU/ml were measured in reactors 1 and 2, respectively, up through hour 126. At 389 and 442 hours, a Clorox/DI water mixture was injected into the reactors. After 90 hours, adhered spore counts in reactor 1 had dropped to undetectable levels, while the same result occurred in reactor 2 after 50 hours. The results of this phase suggest that adhered and planktonic spores are inactivated by free chlorine, but that they persist in a non-chlorinated network. During the second and third phases of experimentation, 1 ml of the spore suspension was injected into both reactors. Addition of the chlorine also began at the time of injection. Initial spore counts in the bulk water ranged from 3 x 104 to 4 x 104 CFU/ml. All bulk measurements dropped to undetectable levels within 24 hours. A comparison of initial adhered spore counts in both reactors for each phase showed that the counts in reactor 2 were significantly lower than in reactor 1. In all reactors, the adhered spore counts rapidly decreased with time, and within 48 hours all adhered spores had disappeared. The results of phases 2 and 3 suggest that the presence of a chlorine residual at the time of injection causes the inactivation of a significant number of spores, that an increased chlorine concentration acts more quickly to inactivate the spores and can help limit adherence to biofouled pipe walls, and that both 1 and 5 mg/l chlorine concentrations were equally as effective at inactivating spores over time.

Part-1: Degradation of PCBs by Ferrous-Peroxymonosulfate oxidation systemPolychlorinated biphenyls (PCBs) in the environment pose long-term risk to public health because of their persistent and toxic nature. This study investigates the degradation of PCBs using sulfate radical-based advanced oxidation processes (SR-AOPs). These processes are based on the generation of sulfate radicals through iron (Fe(II),Fe(III)) mediated activation of peroxymonosulfate (KHSO 5, PMS) or persulfate(Na 2S 2O 8, PS). This study is the first instance for coupling of Fe(II)/Fe(III) with Oxone for PCB degradation in aqueous and sediment systems. The high oxidation efficiencies of the free radicals (SO 4 -•), in combination with the slow rate of consumption of the oxidants, make these processes very effective for the degradation of recalcitrant organic compounds. The effectiveness of the process was evaluated based on the degradation of a model polychlorinated biphenyl, 2-chlorobiphenyl and total organic carbon (TOC) removal. The kinetics of 2-chlorobiphenyl degradation along with the effect of oxidant and catalyst concentrations on the degradation efficiency were studied. Near complete removal of 2-chlorobiphenyl was observed when Fe(II) was used with PMS or PS. Fe(II) acts as a sulfate radical scavenger at higher concentrations indicating that there is an optimum concentration of Fe(II) that leads to most effective degradation of the target contaminant. A chelating agent, sodium citrate, was used to control the quantity of iron in the solution for activation of the oxidant. For the first time, we studied the feasibility of the activation of Oxone using iron-citrate complexes for PCB degradation. In the presence of sodium citrate, increase in degradation efficiency was observed up to a metal: ligand ratio of 1:2, after which the increase in citrate concentration led to a decrease in removal efficiency. Fe(II)/PMS systems were found to be very effective in degrading PCB in a sediment slurry system with more than 90% PCB removal being observed within 24 h. Part-2: Destruction of Chlorophenols by novel radical based oxidation processesThis study examines the feasibility and applications of novel advanced oxidation technologies (AOTs) based on sulfate radicals (SO 4 -•) for US EPA priority pollutants, chlorophenols. A novel class of sulfate radical based homogeneous AOTs (Fe(II)/PS, Fe(II)/PMS,Fe(II)/H 2O 2) was successfully tested for the degradation of series of chlorophenols ( 4-CP, 2,4-CP, 2,4,6-CP, 2,3,4,5-CP). The main objective of the present study was to evaluate the effectiveness of three common peroxide (PMS, PS, H 2O 2) activation by Fe(II) complexes of three representative chelating agents (Citrate, EDDS, and Pyrophosphate) at neutral pH conditions. Short term (4 h) and long term (7 d) experiments were conducted to evaluate the kinetics and longevity of different oxidative systems for 4-chlorophenol degradation. In degradation experiments, remaining contaminant (4-CP), oxidant and soluble iron were monitored with time in an attempt to clearly understand the process of oxidant activation by iron complexes of these three chelating agents. To our best knowledge, this is the first study evaluating the effectiveness of PMS, PS and H 2O 2(common oxidations) for chlorophenol degradation at neutral pH using citrate, pyrophosphate and EDDS as chelating agent. Results showed that certain iron-chelating agent couples were much superior in activating particular oxidant and consequently 4-CP degradation. In case of Fe(II)/PMS system, the inorganic chelating agent pyrophosphate showed the best activation of PMS whereas very fast dissociation of PMS was recorded in case of Fe(II)/EDDS without any apparent 4-CP degradation. In Fe(II)/H 2O 2system, Fe(II)/EDDS complexes were proven to be the most effective and Fe(II)/Pyrophosphate complexes could not activate hydrogen peroxide. Fe(II)/Citrate system showed moderate activation of all three oxidants. Overall, PMS was found the more universal oxidant which was activated by all three iron-chelating agent systems and Fe(II)/Citrate was most universal chelating agent system, which was able to activate all three oxidants up a certain extent.

The effectiveness of nonionic surfactant addition on the bioremediation of polycyclic aromatic hydrocarbons was studied. Specifically, biological responses to synthetic surfactant addition and the surfactant effect on PAH bioremediation were observed. With micellar solubilization, the surfactant could solubilize less soluble PAHs and facilitate the mass transfer of PAHs from solid PAH to the aqueous phase. It appeared that surfactant micelles behave as PAH containing reservoirs which could replenish aqueous phase PAHs quickly. There were fast exchanges of PAHs between the micelle core and the aqueous phase, and micellar phase PAHs could be utilized by PAH degrading bacteria if they had the ability to utilize specific PAHs. Bacterial biofilm formation with extracellular polymeric substances was the strategy of bacteria to utilize partially soluble PAHs in simulated subsurface aquifers. However, in the presence of surfactant, this strategy was modified. The presence of surfactant at all concentrations changed the physiological aspects of the attached biofilm. Based on the elucidated results of the biological responses to surfactant addition, the applicability of use of a permeable reactive biobarrier for surfactant-coupled bioremediation was also observed. The mulch biofilm barrier could prevent the migration of low molecular weight PAHs. However, it couldn’t prevent the migration of micellar solubilized high molecular weight PAHs completely, when surfactant was applied continuously. For the bioremediation of high molecular weight PAHs with surfactant, besides the application of a biobarrier, additional treatment strategies might be required to prevent the migration of the surfactant solubilized PAHs.

A wireless sensor system for measuring ambient carbon monoxide (CO) concentrations, temperature and relative humidity was developed at the University of Cincinnati's Department of Civil and Environmental Engineering and the Center for Distributed and Mobile Computing, the Computer Science Department. The system was designed to utilize an electrochemical sensor, on-board temperature and humidity sensors and a wireless communication system to transmit data to a central processor. An exposure chamber and a validation system were constructed to verify the relationship of the gas sensor response to CO concentrations as a function of relative humidity (RH) and temperature. The responses from the CO wireless sensor system were compared with the data observed by a U.S.EPA reference method non-dispersive infrared (NDIR) analyzer, and National Institutes of Standards and Technology (NIST) traceable thermo-hygrometer. Exposure chamber environmental conditions were operated in the range from 8-35 degreeC, 30-70% relative humidity (%RH) and a CO concentration range of 0-10 ppm. The experimental results provided a good linear correlation between the measured CO signal from the wireless sensor and the concentration as measured by the NDIR analyzer, with a correlation coefficient (R2)~0.99 in the temperature and RH ranges.

Coal has been widely used as primary energy sources including petroleum and natural gas in the United States. Approximately 90% of coal in the United States is attributed to the generation of electricity. Furthermore, due to low cost of coal, the developing countries also generate electricity mainly by coal‐fired power plants. However, coal contains high level of sulfur, ranging from less than 1 % to 10 %, which exists as sulfides, sulfates, pyrite, and organic forms. These sulfur content in coal causes emission of sulfur dioxide (SO 2) through exhaust gas of power plants during coal burning process. In the United States, approximately two third of all SO 2comes from electric power generation that relies on burning fossil fuels like coal 1. As a consequence, the stringent regulatory has regulated the exhaust gas from power plants, resulting in having them equip with flue gas desulfurization technologies. Accordingly, a variety of Flue Gas Desulfurization (FGD) processes has been developed for reducing SO 2exhausted from power plants. These FGD technologies employ various sorbents such as limestone (CaCO 3), lime (CaO), calcium hydroxide (Ca(OH) 2), dolomite (CaCO 3•MgCO 3), magnesium oxide (MgO), sodium carbonate (Na 2CO 3), and sodium bicarbonate (NaHCO 3) for the reduction of SO 2. Among various sorbents used in FGD technologies, in spite of its lower reactivity, calcium hydroxide is most widely used as sorbent because of the lower cost. According to the previous studies, sodium bicarbonate is more efficient in removing SO 2than calcium hydroxide, sodium carbonate or natural trona (Na 2CO 3•NaHCO 3•2H 2O). However, sodium bicarbonate is not as cost efficient as calcium hydroxide or natural trona which is relatively abundant in nature. Since natural trona is composed of approximately 46% sodium carbonate and 36% sodium bicarbonate, a cost‐effective sorbent would be generated by converting sodium carbonate of raw trona to sodium bicarbonate. Hence, the first objective of the study was to develop a cost‐effective method of converting Na 2CO 3of raw trona to NaHCO 3to achieve more efficient removal of SO 2in dry injection systems. Another objective of this study was to elucidate the underlying kinetics and mechanism of how trona decomposes to Na 2CO 3as it reacts with SO 2in a fabric filter collector. Finally, based on the kinetics and mechanism, a model for SO 2removal by trona injection in a fabric filter collector was proposed.

When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on various factors such as oil properties, wave mixing energy, temperature of both oil and water, and salinity of the water. Estuaries represent water with varying salinities. In this study, three salinity values in the range of 10-34 ppt were investigated, representing potential salinity concentrations found in typical estuaries. Three oils were chosen to represent light refined oil, light crude oil and medium crude oil. Each of the oils was tested at three weathering levels to represent maximum, medium and zero weathering. Two dispersants were chosen for evaluation. A modified trypsinizing flask termed the ‘Baffled Flask’ was used for conducting the experimental runs. A full factorial experiment was conducted for each oil to investigate the effect of salinity on three environmental factors: temperature (2 levels), oil weathering (3 levels) and mixing energy (150,200 and 250 rpm). Each experiment was replicated four times in order to evaluate the accuracy of the test. Evaluations were conducted to study the effect of different variables like salinity, weathering, mixing speed and temperature on dispersant effectiveness. Statistical analysis of the data was performed separately on each of the nine oil-dispersant combinations, which revealed the significant factors for each of the combinations. A linear regression model was fit to the experimental data collected

Part A - Removal of Sorbates from Solid Surfaces Soil washing has been found to be an effective cleaning methodology. This study examines the feasibility and effectiveness of a water-miscible organic solvent – lactic acid as an alternative extraction medium for removing PCP from soils. Pentachlorophenol (PCP) is a chlorinated organic compound that has been found in soils at several contaminated sites. Mixed solvents containing water and a water miscible solvent have been found to be more effective in extracting organic contaminants than the organic solvents alone. Our aim was to investigate solutions of lactic acid in water as potential alternatives to remove PCP from three model soils: montmorillonite, sediment from Caesar’s Creek, Ohio and this sediment ignited to remove organic matter. Solutions of different concentrations of lactic acid – water have proven effective in extracting PCP in different spiked soils. PCP extraction was found to be the maximum using a 25% concentration of lactic acid. Richer solutions did not yield a higher removal. The study included optimization of the concentration of lactic acid in water for maximum extraction efficiency and determination and comparison of the extraction of PCP with lactic acid for the three model soils. The effect of organic matter on the extraction was also studied. Initial experiments showed that 24 h was the optimum extraction time. High extraction efficiencies were obtained for montmorillonite (40-80%) and ignited soil (~90%). Caesar’s creek sediment exhibited low PCP extraction due to the presence of soil organic matter. Specific surface area of soil was also found to be an important factor affecting desorption of PCP. This ex-situ washing of soil with varying concentrations of lactic acid has been tested for maximum removal efficiency. Part B – Regeneration of Automotive Catalytic Converters In the regeneration of three way catalytic converters (TWCs), various solvents including biodegradable metal chelating agents, ionic liquids and organic acids were tested. The efficiency of novel environmentally friendly solvents in removing various contaminants such as P, Zn, Pb, Cu and S from commercial three way catalysts (TWC) has been investigated. In the first phase, the aim of our work was to investigate the biodegradable chelating agents [S, S]-ethylenediaminedisuccinic acid (EDDS), iminodisuccinic acid (IDSA), nitrilotriacetic acid (NTA) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoborate, as potential alternatives to organic acids (citric, oxalic and acetic) and compare them with the same for effectiveness. Four samples of catalysts (from front and rear inlets) of two different TWC’s with different mileages and aged under completely different conditions were investigated. In both the samples, zinc removal was found to be dependent on its initial concentration present in the sample. The order of zinc removal was found to be IDSA>EDDS>IL>NTA. The catalysts were also characterized using various techniques – X-Ray diffraction (XRD), SEM (Scanning Electron Microscopy) and BET surface area measurements. In the second phase, the catalyst monolith was washed with only one solvent, EDDS. EDDS was selected of all those solvents tested because of its environmental benignity and its effectiveness in removing sulfur. SEM-EDS images at low magnification (50 μ) showed considerable difference in the surface after washing. However, our XRD results indicated that there was no removal of major poison compound phases. Correspondingly, little or no enhancement in Brunauer-Emmett-Teller (BET) surface area was observed between used and the washed samples.

Precise manipulation of matter at the nanoscale will enhance our potential to synthesize materials with tailor-designed properties and functionalities for their environmental applications. This dissertation explores the development of innovative nanotechnological procedures for the preparation of highly efficient visible light-activated nanostructured TiO2 photocatalytic particles, films, membranes, and devices for environmental applications. Nanocrystalline TiO2 particles and immobilized films and membranes with mesoporous inorganic network were prepared via a sol-gel method modified with surfactants as pore-directing agents. Not only did we manipulate the physicochemical properties of TiO2 such as crystallographic structure, particle size, and defect structure but also tailor-design its structural properties such as surface area, pore volume, and pore size distribution. Asymmetric mesoporous multilayer TiO2 photocatalytic membranes exhibiting hierarchical changes in pore diameter and materials porosity were also fabricated. These TiO2 films and membranes inherently possessed multiple and simultaneous functions including photocatalytic decomposition of organic pollutants, inactivation of pathogenic microorganisms, physical separation of contaminants, and anti-biofouling action. In addition, for the design of solar-driven treatment technologies, highly efficient visible light-activated TiO2 photocatalysts with mesoporous structure and narrowed band gap energy were synthesized by introducing nitrogen-containing surfactant as a pore templating material as well as a nitrogen dopant in the sol-gel method of TiO2 For the development of highly sensitive and stable electrochemical sensors to detect a neurotransmitter, catechol, sonogel carbon electrodes were modified with the nanostructured TiO2 acting as an adsorbent for catechol and a redox mediator for electron transfer. We also elucidated the formation of nanocrystalline TiO2 particles at ambient synthesis conditions via sol-gel method employing water immiscible room temperature ionic liquid as reaction medium and modified with surfactant as pore template. Detail information on the preparative method, synthesis route and mechanism, crystallographic and structural properties, and photocatalytic activity of the nanocrystalline TiO2 particles with thermal stability was investigated. From a scientific point of view, this study will provide new nanotechnological and materials chemistry procedures to synthesize highly efficient photocatalytic TiO2 particles, films, and membranes that can be used for the treatment and disinfection of water and wastewater under even visible light irradiation, and highly sensitive TiO2-based devices for the development of new type of sensors.

Polycyclic aromatic hydrocarbons (PAHs) are of major concern because of their toxicity to human health and to natural ecology. The co-presence of heavy metal wastes may hinder or prevent the biodegradation of some of PAHs. A macro-micro-molecular methodology was used to study the impact of cadmium on a multi-species biofilm degrading naphthalene and the role of hydrogen peroxide in the toxicity-resistance interaction between cadmium and the biofilm. The impact of cadmium and hydrogen peroxide on the biofilm was studied in batch experiments; cadmium transport and distribution and the micro-environmental profiles of dissolved oxygen and redox potential were investigated with microelectrodes; and microbial community changes in the biofilm were observed using CLSM combined with fluorescence probes. Cd2+ sorption in the biofilms was a rapid and highly pH dependent process. Cd2+ started to transport into the biofilm once the contact started. Cd2+ penetrated the biofilm in less than one hour. Most sorption occurred during the first two hours. Naphthalene removal had good correlation with Cd2+ sorption. The biofilm behavior toward naphthalene removal could be divided into three phases. The minimum Cd2+ inhibitory capacity for the biofilms and the Cd2+ inhibition range were defined as 5 µg Cd/mg VS and from 5 to 10 µg Cd/mg VS, respectively. A multi-species biofilm was found to have the ability to resist external inhibitors such as Cd2+. Naphthalene removal and dissolved oxygen consumption were retarded by Cd2+ but were resumed after the retardation period. The dominant components of the microbial community switched from round/rod cells to filamentous microorganisms. However, hydrogen peroxide increased the vulnerability of the biofilm to Cd2+ toxicity. When H2O2 was present, naphthalene removal was significantly inhibited by Cd2+ and did not resume at the end of the experiment. Filamentous microorganisms, which were prolific when only Cd2+ was added, were not found to be dominant in the microbial community. A multi-species biofilm developed a resistance upon external inhibition, by making the species that are more tolerant to Cd2+ the dominant ones. However, this resistance was prevented from developing due in the presence of H2O2 which may make the biofilm more vulnerable to Cd2+.

The objective of this project was to evaluate methods for possibly overcoming limitations of methanol addition for full-scale facilities that have limited available anoxic solids retention time (SRT). There is considerable uncertainty associated with the denitrification potential of aerobically grown methylophilic bacteria and its effect on full-scale plant design/operation. It was hypothesized that methanol addition under aerobic conditions (bleeding a small amount of methanol into the aerobic zone of a BNR process) could alleviate anoxic SRT limitations in a full-scale plant by increasing the active methylotrophic biomass content in the process. It is critical to understand denitrification kinetics under these conditions. To perform this research, 3.5 liter sequencing batch reactors were operated to observe methanol acclimation. Data was collected by monitoring the SBRs to determine the specific denitrification rate (SDNR). Once the SBRs stabilized, High Food to Microorganism tests were performed to determine the maximum anoxic growth rate of the methanol denitrifiers.

In Peoria, Arizona during the autumn season of 2002, two young children died from Primary amoebic meningoencephalitis (PAM) infections. Naegleria fowleri, was detected in the residual water from household pipes and sinks and was linked to the cause of PAM infections that resulted in the death of both children. In this study, we tested the same groundwater in Peoria, Arizona that was suspected to be contaminated by N. fowleri, for the presence of N. fowleri. Results of the study indicated the presence of N. fowleri in 12 samples. Five samples were analyzed for bacterial communities, of which three were PCR positive for N. fowleri. Analysis of bacterial communities present in the Peoria groundwater samples indicated the presence of Beta-proteobacteria such as Caldimonas manganoxidans, Leptothrix species, Aquabacterium species and bacteria of other genus such as Chloroflexus, Cytophaga, Flexibacter, Halochromatium, Meiothermus, Nitrospira, Nocardia, Rasbo bacterium, and Thermus.

Fluctuations in influent concentrations and variations in waste air composition challenge the application of biofiltration technology in the chemical industry. An integrated system of a cyclic 2-bed adsorption/desorption unit and a trickle bed air biofilter (TBAB) is proposed and applied in this study. The primary goal of the study was to maintain long-term, stable consistent high performance of volatile organic compounds (VOCs) degradation in the TBAB. Five specific studies were conducted to accomplish the primary objective. Investigations were conducted on independent TBABs under single VOC interchange with periodic backwashing as biomass control. The VOCs considered were common solvents used in paint booth industries. Two aromatic compounds (styrene and toluene) and two aliphatic compounds (Methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK)) were studied. This study simulated VOC emission rotation as the process of production rotated in certain chemical industries. Experimental findings indicated that the biofilter required apparent re-acclimation period when the VOC was interchanged to aromatic ones. The second phase investigated two mixtures of these VOCs in two independent parallel trains of TBAB under step change in influent concentration. Critical loadings were determined under backwashing and starvation operating strategies. In the third phase, the buffering capacity of a cyclic 2-bed adsorption unit under a square wave of fluctuating condition was evaluated for a feeding composition based on EPA industrial emission report. The cyclic 2-bed adsorption unit succeeded in attenuating load fluctuations as compared to non-cyclic operations. Furthermore, the time to breakthrough of contaminants encountered in non-cyclic operations could lead to a starvation period to the followed biofilter and eventually long period of acclimation after breakthrough of VOCs from the adsorber. In the fourth phase, the integrated system of 2 cyclic adsorption/desorption beds and TBAB was applied to the VOC mixture. Four square wave feeding conditions were applied on the system. A parallel control system with an independent TBAB only was run to compare its performance to the integrated system. Experimental findings revealed that the integrated system was able to achieve high stable performance as compared to the control unit. Finally, microbial communities were investigated for the biofilters utilized in VOC interchange and VOCs mixture experiments. Microbial diversity showed consistent transition for the interchange of VOCs. Community structure for VOC mixtures showed high independency to the component content in the mixture.

Membrane bioreactors (MBRs) are promising technology for ground based wastewater treatment. Recently, MBRs are also being considered to be used as a component in the integrated water recovery system for long duration manned space missions. For long term manned space travel, the major operational problem for MBRs is membrane biofouling. The current research studied the influence of MBR loading/decanting patterns on membrane biofouling. The central hypothesis of this study was: MBR loading/decanting patterns could lead to different sludge properties resulting in different level of membrane biofouling. To test the central hypothesis, experiments covered the following aspects of MBRs treating synthetic Early Planetary Base Wastewater (EPBW) were carried out: 1) organic removal and nitrification performance; 2) influence of MBR loading/decanting patterns (continuous mode vs. batch mode) on sludge properties; 3) influence of MBR loading/decanting patterns on microbial community structure of the planktonic biomass; 4) influence of MBR loading/decanting patterns on membrane filtration characteristics; and 5) the potential pioneer species that could attach to membrane surface in cross-flow microfiltration. The results of this study suggested that 1) MBRs is a promising process as the preliminary treatment of the synthetic EPBW by showing excellent organic removal and nitrification; 2) MBR loading/decanting patterns impact the chemical/physical properties as well as the microbial community structure of the planktonic (suspended) biomass. Particularly, the physical/chemical properties of the sludge in the MBR with batch mode could result in less membrane fouling; 3) Sludge in the MBR with batch loading/decanting correlated with less membrane fouling in both cross-flow and submerged filtrations; and 4) Specific microbial populations could be pioneers that firmly attach to microfiltration membranes at the initial stage of membrane biofouling. The findings of the current study provided novel information on the treatment of EPBW by using MBR technology that could also be used for the design and operation of MBRs for ground-based high strength wastewater treatment. More importantly, the results of this research suggested that the loading/decanting operation of the bioreactor components of MBRs could lead to different levels of membrane biofouling. Future design and operation of MBRs, for both long duration manned space mission and ground-based applications, should consider the operating condition of the bioreactor to further reduce the cost and enhance the stability of MBRs. As one of the early steps towards the mechanisms of membrane biofouling, molecular analysis suggested that specific microbial populations could be responsible for the initiation of membrane biofouling. This result could be an important connection between engineering and microbiological research for biofilm/biofouling formation.

Synthesis of high performance titania photocatalytic films with good structural integrity is an important aspect in the design of high-efficiency photocatalytic reactors for water purification. One aspect of this dissertation deals with employing new approaches based on template-assisted Degussa P25 TiO2 powder modified sol gel processes for the synthesis of tailor-designed porous TiO2-P25 composite films with good structural integrity for water purification. A relatively low Degussa P25 loading (i.e., 10 g/L in the sol) is employed, which can avoid crack formation in the films. High porosity induced by the combined effect of template such as polyethylene glycol (PEG 2000) or polyoxyethylene (20) sorbitan monolaurate (Tween 20) with Degussa P25 can be beneficial to the exposure of the maximum number of high active Degussa P25 nanocrystallites in the inner layers to the solid-liquid interface. Moreover, the formation of P25 associated larger pores (i.e., macropores or larger mesopores) is beneficial to fast mass transfer of the treated contaminants in the larger pore channels. As a result, the enhancement in photocatalytic activity induced by low loading P25 is high. For the TiO2-P25 composite films prepared by a PEG-assisted P25 modified sol gel method (i.e., PPMSGF-PEG), the optimum calcination temperature is 500&degC under which improved BET surface area/ porosity and a bimodal macro-mesoporous structure can be formed. For mesoporous TiO2-P25 composite films prepared by a Tween 20-assisted P25 powder modified sol gel method, the optimum Tween 20 loading is 50% (v/v) in the sol under which high BET surface area (74 m²/g) / porosity (50.6%), bimodal mesoporous structure and larger film thickness can be obtained. On the other hand, the pore structure of photocatalytic films prepared by a P25 powder modified sol gel method (i.e., PPMSGFs) and in the absence of templates can be improved and the amount of surface foreign metal ions (i.e., Cr³+) diffused from the stainless steel support during heat treatment can be decreased by increasing P25 loading from 0 to 50g/L in the sol or decreasing calcination temperature from 600 to 500-400&degC. However, crack formation cannot be avoided for the PPMSGFs with high P25 loading (i.e., 50 g/L in the sol) in this study. Another aspect of this dissertation is to address some challenging issues in the formation of unique structures of TiO2 films using various sol gel methods without Degussa P25 TiO2 nanoparticles addition. By decreasing calcination temperature from 600 to 500&degC, a crack free and thick TiO2 film with optimum film thickness (10 µm) as well as low porosity (~5%) and narrow pore size distribution (2-10 nm) was successfully prepared. Moreover, the macro-mesoporous texture of thick TiO2 films without crack formation was obtained by optimizing the PEG 2000 loading in the sol (i.e., 20 g/L PEG 2000). Tween 20 was found to be an effective template in a non-acidic sol gel system. Optimization of Tween 20 loading (i.e., Tween 20: final sol = 50%, (v/v)) in the sol) resulted in the formation of relatively ordered mesoporous structure of TiO2 films with anatase nanocrystallites of ultrafine size (~7 nm), high BET surface area (~120 m² /g) and high pore volume (~0.155 cm³/g). The advantages of the above unique structures of the as-prepared TiO2 films in the application of various water purification systems are emphasized.

Preliminary experiments and 9 trials were conducted to evaluate a bench scale wastewater treatment experiment. Wastewater consisted of 3 heavy metals including cadmium (Cd), copper (Cu), and lead (Pb). An organic pollutant, phenol, was added at 4 concentrations ranging from 0 to 250 mg/L. Organic substrate was used at 3 levels of strength corresponding to high, medium, and low. Treatment consisted of 2 phases, a physical-chemical removal of metal with an ion exchange mineral known as zeolite and biological oxidation through bioaugmentation. Zeolite was added at doses of high, medium, low, and a reference of zero. Bioaugmentation consisted of 4 types of Live Liquid MicroOrganisms (LLMO) including strains E1, S1, G1, and N1. Pb was effectively removed with up to 100% removal while Cd and Cu were not as effectively removed. Success of bioaugmentation was measured using a total organic carbon analyzer and results were mixed. LLMO improved biological oxidation at the lowest organic substrate levels after ion exchange. Pb wastewaters with a high dose of zeolite, phenol concentrations of low or zero, and low organic substrate showed the best total organic carbon removal performance with the addition of LLMO. LLMO strains of E1, S1, and G1 showed slightly better performance over N1.

Comingled organic and metallic pollutants challenge soil remediation efforts because of their distinct chemical and biological transformation behavior. Bioremediation of such wastes depends upon pollutant types, remediation endpoints, and microbial metabolism and habitat. This research examined relationships between habitat, cell physiology, and aerobic biotransformation of chromium and organics. It was hypothesized that the degree of soil attachment by culturable heterotrophic bacterial communities in the vadose zone correlates to chromium biosorption, reduction, and tolerance; cell surface properties; growth rate; and substrate affinity. Compared to weakly soil-associated communities, strongly-associated communities were expected to have slower growth and greater substrate affinity, hydrophobicity, and chromium tolerance. Community-level relationships were not expected to hold true at the population level, however. Instead, bacterial isolates were anticipated to exhibit cell surface properties and biotransformation behavior not necessarily linked to their original soil association or community. The research sought to identify the biotransformation potential of often-overlooked soil microorganisms and to assess their use in achieving low residual contaminant concentrations in comingled chromium wastes. Serial elution was used to extract two variably-attached bacterial communities from noncontaminated vadose zone soil. Five microbial isolates were cultured from these consortia. Consortia and isolates were characterized with respect to: 1. cell surface hydrophobicity and charge, using solvent-, resin-, and titration-based tests; 2. the rate and extent of growth on yeast extract and salicylic acid, a model organic pollutant; 3. chromium toxicity under variable substrate conditions; 4. chromium reduction, measured via x-ray spectroscopy; and 5. the kinetics and extent of chromium biosorption. As hypothesized, the easily-detached bacterial community (F1) was less hydrophobic than its counterpart (F3), but its isolates varied unpredictably in hydrophobicity. Furthermore, F1 exhibited faster Monod-type growth but lower affinity for yeast extract (µmax=0.35 1/hr, Ks=36.6 mg/L) than F3 (µmax=0.30 1/hr, Ks=12.2 mg/L), whereas its isolates showed growth variability. Salicylic acid generally produced non-Monod growth and increased apparent chromium toxicity. All isolates and consortia were able to sorb and reduce chromium, regardless of cell surface properties or original attachment. Chromium resistance was negatively correlated to substrate (yeast extract) affinity among isolates, positively correlated to the substrate affinity of consortia (as hypothesized), and independent of cell surface properties.

Development-related increases in stormwater runoff have been linked to nonpoint source pollution in receiving waters, higher susceptibility of eroded land to flooding and degradation of in-stream wildlife habitat. Strong connections with surrounding landscape processes make headwater streams particularly susceptible to these problems. Urban stormwater management has traditionally focused on the use of detention basins and other structural Best Management Practices (BMPs) to temporarily store runoff and thereby reduce postdevelopment peak flows. Unfortunately, detention-based BMPs do not address the increased volume of runoff that is discharged from a site once it has been developed. Left uncontrolled, the excess runoff may produce significant erosion and flooding in downstream reaches. Infiltration-based BMPs such as preserving stream buffers and directing rooftop runoff to vegetated areas may provide a viable means for reducing stormwater runoff. For this study, the effectiveness of detention-based BMPs and infiltration-based BMPs was compared with respect to reducing peak flow exceedances and the total volume of runoff at Shayler Crossing, a 244-acre headwatershed in southwest Ohio. Ten years of continuous precipitation data were used to simulate rainfall-runoff at Shayler Crossing with the U.S. Environmental Protection Agency’s Storm Water Management Model (SWMM). Based on simulated postdevelopment peak flow exceedances, it appears as though peak flow control provided by upstream detention-based BMPs is not reflected at the headwatershed scale. Model output also suggests that preserving a 200’ wide stream buffer area would lower postdevelopment peak flow exceedances from current levels. The stream buffer area, however, would reduce the existing volume of runoff significantly more (50% versus 10% reduction) than the disconnected rooftops. Moreover, it estimated that the stream buffer area could be implemented for $156,618 less than the existing BMPs. This implies that stream buffer preservation is a better and more cost-effective option for stormwater management at Shayler Crossing.