Matching Items (9)

Impact of Misting Systems on Local Air Quality

Description

-Please adjust the format of the abstract. m-3 should be typed as "m to the minus 3" with the "minus 3" in superscript
-see the additional "abstract.pdf" document for formatting
In arid environments like Phoenix, many professional and residential outdoor

-Please adjust the format of the abstract. m-3 should be typed as "m to the minus 3" with the "minus 3" in superscript
-see the additional "abstract.pdf" document for formatting
In arid environments like Phoenix, many professional and residential outdoor spaces are cooled by the use of misting systems. These systems spray a fine mist of water droplets that cool down the surrounding air through the endothermic evaporation process. When the water droplets evaporate, they leave behind dissolved material that is present in the water, generating ambient particulate matter (PM). Thus, misting systems are a point source of PM. Currently there is no information on their impact on air quality in close proximity to these systems, or on the chemical composition of the particulate matter generated by the evaporating mist.
In this project, PM concentrations are found to increase on average by a factor of 8 from ambient levels in the vicinity of a residential misting system in controlled experiments. PM concentrations in public places that use misting systems are also investigated. The PM10 concentrations in public places ranged from 0.102 ± 0.010 mg m-3 to 1.47 ± 0.15 mg m-3, and PM2.5 ranged from 0.095 ± 0.010 mg m-3 to 0.99 ± 0.10 mg m-3. Air quality index (AQI) values based on these concentrations indicate that these levels of PM range from unhealthy to hazardous in most cases. PM concentrations tend to decrease after remaining relatively constant with increasing distance from misting systems. Chemical data reveal that chloride and magnesium ions may be used as tracers of aerosolized water from misting systems. The average chloride concentration was 71 µg m-3 in misting samples and below the detection limit for Cl- (< 8.2 µg m-3) in ambient samples. The average magnesium concentration was 11.7 µg m-3 in misting samples and 0.23 µg m-3 in ambient samples.

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2020-05

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Ammonium and potassium removal from real hydrolyzed urine using natural zeolites

Description

The goal of this research was to study the effect of dilution on ammonium and potassium removal from real hydrolyzed urine. The performance of two natural zeolites, clinoptilolite and chabazite, was studied and compared with the help of batch equilibrium

The goal of this research was to study the effect of dilution on ammonium and potassium removal from real hydrolyzed urine. The performance of two natural zeolites, clinoptilolite and chabazite, was studied and compared with the help of batch equilibrium experiments at four dilution levels: 100%, 10%, 1% and 0.1% (urine volume/total solution volume). Further, the sorption behavior of other exchangeable ions (sodium, calcium and magnesium) in clinoptilolite and chabazite was studied to improve the understanding of ion exchange stoichiometry. Ammonium and potassium removal were highest at undiluted level in samples treated with clinoptilolite. This is a key finding as it illustrates the benefit of urine source separation. Chabazite treated samples showed highest ammonium and potassium removal at undiluted level at lower doses. At higher doses, potassium removal was similar in undiluted and 10% urine solutions whereas ammonium removal was the highest in 10% urine solutions. In general, chabazite showed higher ammonium and potassium removal than clinoptilolite. The result showed that ion exchange was stoichiometric in solutions with higher urine volumes.

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Date Created
2019

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Effect of anion exchange resin properties on the adsorption of PFAAs and NOM

Description

Humans are exposed up to thousands of per- and polyfluoroalkyl substances (PFAS) in the environment, but most of the research and action has been directed towards only two PFAS compounds. These two compounds are part of a subcategory of PFAS

Humans are exposed up to thousands of per- and polyfluoroalkyl substances (PFAS) in the environment, but most of the research and action has been directed towards only two PFAS compounds. These two compounds are part of a subcategory of PFAS called perfluoroalkyl acids (PFAAs). It has been a challenge for the environmental community to mitigate risks caused by PFAAs due to their high persistence and lack of effective measures to remove them from the environment, especially in heavily impacted areas like fire-training sites. The goal of this work was to further answer some questions regarding the removal of PFAAs in the environment by looking at anion exchange resin characteristics and presence of a competing compound, natural organic matter (NOM), in the adsorption of environmentally relevant PFAS compounds including the two often monitored 8-carbon chain PFAAs. Two different resins were tested with two forms of counterions, in both groundwater and NOM impacted groundwater. Resin polymer matrix was the most important property in the adsorption of PFAAs, the two resins used A520E and A860 had similar properties except for their matrices polystyrene (PS) and polyacrylic (PA), respectively. The PS base is most effective at PFAAs adsorption, while the PA is most effective at NOM adsorption. The change in the counterion did not negatively affect the adsorption of PFAAs and is, therefore, a viable alternative for future studies that include regeneration and destruction of PFAAs. The presence of NOM also did not significantly affect the adsorption of PFAAs in the PS resin A520E, although for some PFAAs compounds it did affect adsorption for the PA resin. Ultimately, PS macroporous resins with a strong Type I or Type II base work best in PFAAs removal.

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Date Created
2019

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Review of the Quantitative Tradeoffs of Using Organic Residuals in Arid Agriculture

Description

Water reuse and nutrient recovery are long-standing strategies employed in agricultural systems. This is especially true in dry climates where water is scarce, and soils do not commonly contain the nutrients or organic matter to sustain natural crop growth. Agriculture

Water reuse and nutrient recovery are long-standing strategies employed in agricultural systems. This is especially true in dry climates where water is scarce, and soils do not commonly contain the nutrients or organic matter to sustain natural crop growth. Agriculture accounts for approximately 70% of all freshwater withdrawals globally. This essential sector of society therefore plays an important role in ensuring water sources are maintained and that the food system can remain resilient to dwindling water resources. The purpose of this research is to quantify the benefits of organic residuals and reclaimed water use in agriculture in arid environments through the development of a systematic review and case study. Data from the systematic review was extracted to be applied to a case study identifying the viability and benefits of organic residuals on arid agriculture. Results show that the organic residuals investigated do have quantitative benefits to agriculture such as improving soil health, reducing the need for conventional fertilizers, and reducing irrigation needs from freshwater sources. Some studies found reclaimed water sources to be of better quality than local freshwater sources due to environmental factors. Biosolids and manure are the most concentrated of the organic residuals, providing nutrient inputs and enhancing long-term soil health. A conceptual model is presented to demonstrate the quantitative benefits of using a reclaimed water source in Pinal County, Arizona on a hypothetical crop of cotton. A goal of the model is to take implied nutrient inputs from reclaimed water sources and quantify them against standard practice of using irrigated groundwater and conventional fertilizers on agricultural operations. Pinal County is an important case study area where farmers are facing cuts to their water resources amid a prolonged drought in the Colorado River Basin. The model shows that a reclaimed water source would be able to offset all freshwater and conventional fertilizer use, but salinity in reclaimed water sources would force a need for additional irrigation in the form of a large leaching fraction. This review combined with the case study demonstrate the potential for nutrient and water reuse, while highlighting potential barriers to address.

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2020

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Meta-analysis of error sources in the determination of micro- and nanoplastics

Description

The occurrence of micro-and nanoplastic (MNP) debris in the environment is a research area of considerable public health concern. Various combinations of methods for extraction, isolation, and quantification of MNP have been applied but literature studies evaluating the appropriateness and

The occurrence of micro-and nanoplastic (MNP) debris in the environment is a research area of considerable public health concern. Various combinations of methods for extraction, isolation, and quantification of MNP have been applied but literature studies evaluating the appropriateness and efficacy of these protocols are lacking. A meta-analysis of the literature (n=134; years 2010-2017) was conducted to inventory and assess the appropriateness of methodologies employed. Some 30.6% of studies employed visual identification only, which carried a calculated misidentification error of 25.8-74.2%. An additional 6.7% of studies reported counts for particles smaller than the cutoff value of the selected collection pore size, and 9.7% of studies utilized extraction solution densities which exclude some of the polymers commonly occurring in the environments investigated. A composite value of data vulnerability of 43.3% was determined for the sample, indicating considerable weaknesses in the robustness of information available on MNP occurrence and type. Additionally, the oxidizing solutions documented in the literature frequently were deemed unsuccessful in removing interfering organic matter. Whereas nanoplastics measuring <1 µm in diameter are likely principal drivers of health risk, polymer fragments reported on in the literature are much larger, measuring 10+ µm in diameter due to lack of standardized methods. Thus, current inventories of MNP in the environmental MNP feature data quality concerns that should be addressed moving forward by using more robust and standardized techniques for sampling, processing and polymer identification to improve data quality and avoid the risk of misclassification.

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Date Created
2018

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Comparative Exposure Assessment of Antibiotic Resistance Determinants in Biosolids in Fertilizer Application to Lettuce Crops

Description

Water is a scarce resource that is recycled through wastewater treatment plants (WWTPs) to help fulfill the demand for water. Agriculture is a large consumer of water, indicating that WWTP-treated water is proportionally applied to crops at a high rate.

Water is a scarce resource that is recycled through wastewater treatment plants (WWTPs) to help fulfill the demand for water. Agriculture is a large consumer of water, indicating that WWTP-treated water is proportionally applied to crops at a high rate. Recycled water is highly regulated but is capable of containing high-risk pathogens and contaminants despite the efforts of physical and microbial treatments throughout the WWTP process. WWTPs are also producers of biosolids, treated sewage sludge regulated by the EPA that can be applied in agricultural settings to act as a fertilizer. Biosolids are a useful fertilizer as they are rich in nitrogen and contain many beneficial nutrients for soil and crops. Due to biosolids being a by-product of recycled water, they are susceptible to containing the same pathogens and contaminants that can be transferred in the WWTP systems. Antibiotic resistance (AR) is an ever-growing threat on a global scale and is one of the areas of concern for consideration of pathogen spread from WWTPs. Antibiotic resistance bacteria, created through mutation of bacterial plasmids producing antibiotic resistance genes (ARGs), have been quantified and studied to help mitigate the risk posed by continued AR spread in the environment. This study aims to produce a comprehensive collection of quantified ARG concentration data in biosolids, as well as producing a QMRA model integrating Monte Carlo distributions to provide groundwork for understanding of the direct dosage and consumption of ARGs to the standard U.S. citizen. The study determined that sul1, sul2, tetM, and tetO are ARGs of high concern in biosolid samples based on current concentration data of biosolid samples. The resulting dose models and gene concentration distributions provide data to support the need to mitigate AR risk presented by agricultural biosolid application.

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2022-05

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Advancing the Implementation and Adoption of Urine Diversion Systems in Commercial and Institutional Buildings in the United States: A Focus on Control of Urea Hydrolysis

Description

This dissertation focused on the implementation of urine diversion systems in commercial and institutional buildings in the United States with a focus on control of the urea hydrolysis reaction. Urine diversion is the process by which urine is separately collected

This dissertation focused on the implementation of urine diversion systems in commercial and institutional buildings in the United States with a focus on control of the urea hydrolysis reaction. Urine diversion is the process by which urine is separately collected at the source in order to realize system benefits, including water conservation, nutrient recovery, and pharmaceutical removal. Urine diversion systems depend greatly on the functionality of nonwater urinals and urine diverting toilets, which are needed to collect undiluted urine. However, the urea hydrolysis reaction creates conditions that lead to precipitation in the fixtures due to the increase in pH from 6 to 9 as ammonia and bicarbonate are produced. Chapter 2 and Chapter 3 describes the creation and use of a cyber-physical system (CPS) to monitor and control urea hydrolysis in the urinal testbed. Two control logics were used to control urea hydrolysis in realistic restroom conditions. In the experiments, acid was added to inhibit urea hydrolysis during periods of high and low building occupancy. These results were able to show that acid should be added based on the restroom use in order to efficiently inhibit urea hydrolysis.
Chapter 4 advanced the results from Chapter 3 by testing the acid addition control logics in a real restroom with the urinal-on-wheels. The results showed that adding acid during periods of high building occupancy equated to the least amount of acid added and allowed for urea hydrolysis inhibition. This study also analyzed the bacterial communities of the collected urine and found that acid addition changed the structure of the bacterial communities.
Chapter 5 showed an example of the capabilities of a CPS when implemented in CI buildings. The study used data mining methods to predict chlorine residuals in premise plumbing in a CI green building. The results showed that advance modeling methods were able to model the system better than traditional methods. These results show that CPS technology can be used to illuminate systems and can provide information needed to understand conditions within CI buildings.

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Date Created
2021

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Exploring Intensive Agriculture and Organic Fertilizer Management in the US: Implications for Nutrient Pollution Prevention

Description

Intensified food production on large farms across the world has led to discussions on how to facilitate sustainable policies and practices to reduce nutrient pollution. In Chapter 1, I evaluated the co-variability of agricultural intensification, environmental degradation, and socio-economic indicators

Intensified food production on large farms across the world has led to discussions on how to facilitate sustainable policies and practices to reduce nutrient pollution. In Chapter 1, I evaluated the co-variability of agricultural intensification, environmental degradation, and socio-economic indicators throughout the US to explore the potential evidence for the existence of sustainable intensification of agriculture in the US. I identified distinct agro-social-eco regions in the US that provide background for future regional studies of (sustainable intensification) SI in the US and beyond. I observed regions of moderate agricultural intensity and lower environmental degradation within the Great Plains, and regions of high agricultural intensity and higher environmental degradation throughout portions of the Midwest. Insights gained from this study can provide roadmaps for improved sustainable agricultural intensification within the US. In Chapter 2, the study summarized state regulations controlling a key nutrient input - the land application of biosolids from human wastewater treatment and manures from regulated animal feeding operations. Results indicate high variability of both manure and biosolids regulations among the states and stark differences in the regulation of land application of biosolids versus manures. This work can be used to identify opportunities for the strengthening of regulatory frameworks for managing these resources with minimal risk to the environment. In Chapter 3, I combined aspects of the previous chapters to understand the potential impact of specific CAFO land application regulations on nutrient pollution and assess if stricter regulations related to better environmental outcomes. I compared TN AND TP accumulated yields in surface waters across US States with state specific CAFO land application regulations across US Policy scenario tests revealed that more restrictions were associated with higher nutrient levels, indicating reactive policy making and delayed nonpoint source pollution responses. Overall, I found that fostering adaptive capacity and management within delineated agro-social-eco regions will likely facilitate sustainable food systems in the US.

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Date Created
2021

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Assessing Biofilm Growth on Pristine and Aged Microplastics Exposed to Tempe Town Lake Water

Description

This study investigated the difference in biofilm growth on pristine and aged polypropylene microplastics exposed to Tempe Town Lake water for 8 weeks. The research question here is, does the aging of microplastic (MPs) change the biofilm formation rate and

This study investigated the difference in biofilm growth on pristine and aged polypropylene microplastics exposed to Tempe Town Lake water for 8 weeks. The research question here is, does the aging of microplastic (MPs) change the biofilm formation rate and composition of the biofilm in comparison with the pristine MPs. To answer this question, the biofilm formation was quantified using different methods over time for both pristine polypropylene and aged polypropylene using agar plate counts and crystal violet staining. Colony counts based on agar plating showed an increase in microbial growth over the 8 weeks of treatment, with the aged MPs accumulating higher microbial counts than the pristine MPs. The diversity of the biofilm decreased over time for both MPs and the aged MPs had overall less diversity in biofilm, based on phenotype enumeration, in comparison with the pristine MPs. Higher biofilm growth on aged MPs was confirmed using crystal violet staining, which stains the negatively charged biological compounds such as proteins and the extracellular polymeric substance matrix of the biofilm. Using this complementary approach to colony counting, the same trend of higher biofilm growth on aged MPs was found. Further studies will focus on confirming the phenotype findings using microbiome analysis following DNA extraction. This project created a methodology to quantify biofilm formation on MPs, which was used to show that MPs may accumulate more biofilms in the environment as they age under sunlight.

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Date Created
2022