Matching Items (10)

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Drinking Water Quality and Management in Arizona

Description

Access to clean drinking water has been identified by the National Academy of Engineering as one of the Grand Challenges of the 21st century. This thesis investigated clean drinking water

Access to clean drinking water has been identified by the National Academy of Engineering as one of the Grand Challenges of the 21st century. This thesis investigated clean drinking water access in the greater Phoenix area, specifically with regards to drinking water quality standards and management strategies. This research report provides an introduction to water quality, treatment, and management; a background on the Salt River Project; and an analysis on source water mix and drinking water quality indicators for water delivered to Tempe, Arizona water treatment facilities.

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Date Created
  • 2016-12

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Assessment of Antibiotic Resistance in a Managed Aquifer Recharge System: Water Sustainability and Water Quality

Description

Managed Aquifer Recharge is an increasingly prevalent solution to sustain water availability in arid regions. Recharge of groundwater resources using treated wastewater effluent is one type of managed aquifer recharge

Managed Aquifer Recharge is an increasingly prevalent solution to sustain water availability in arid regions. Recharge of groundwater resources using treated wastewater effluent is one type of managed aquifer recharge that offers long-term sustainable water management. However, there are some concerns regarding the reuse of wastewater and its potential to increase exposures to antibiotic resistant bacteria and antibiotic resistance genes that could affect human health. Antibiotic resistance genes can confer the ability for bacteria to resist antibacterial treatment, rendering their presence in water supplies as an area of research needed to evaluate where environmental “hot spots” of potential antibiotic resistance disseminate. To evaluate the occurrence of antibiotic resistant bacteria and antibiotic resistance genes, sampling of an Arizona managed aquifer recharge facility was performed, with target antibiotic resistance genes measured using quantitative polymerase chain reaction. The occurrence of antibiotic resistance genes was evaluated at several sampling wells and in sediments to examine trade-offs between water quantity benefits and water quality issues. The goal of this work is to inform management operations for secure water quality in the face of climate change.

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Date Created
  • 2021-05

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Community composition and nitrogen retention in an aridland wastewater treatment wetland

Description

City managers and policy makers are increasing looking to environmental systems to provide beneficial services for urban systems. Constructed wetland systems (CWS), highly managed and designed wetland ecosystems, are being

City managers and policy makers are increasing looking to environmental systems to provide beneficial services for urban systems. Constructed wetland systems (CWS), highly managed and designed wetland ecosystems, are being utilized to remove pollution, particularly excess nitrogen (N), from treated wastewater. Various wetland process remove N from effluent, such as denitrification, direct plant uptake, and soil accumulation. Emergent macrophytes provide direct uptake of N and improve conditions for microbially-mediated N processing. The role of different macrophytes species, however, is less understood and has primarily been examined in mesocosm and microcosm experiments and in mesic environments. I examined the effects of community composition on N removal and processing at the whole ecosystem scale in an aridland, constructed wetland (42 ha) through: 1) quantifying above- and belowground biomass and community composition from July 2011 \u2014 November 2012 using a non-destructive allometric technique, and; 2) quantifying macrophyte N content and direct macrophyte N uptake over the 2012 growing season. Average peak biomass in July 2011 & 2012 was 2,930 g dw/m2 and 2,340 g dw/m2, respectively. Typha spp. (Typha domingensis and Typha latifolia) comprised the majority (approximately 2/3) of live aboveground biomass throughout the sampling period. No statistically significant differences were observed in macrophyte N content among the six species present, with an overall average of 1.68% N in aboveground tissues and 1.29% N in belowground tissues. Per unit area of wetland, Typha spp. retained the most N (22 g/m2); total N retained by all species was 34 g/m2. System-wide direct plant N uptake was markedly lower than N input to the system and thus represented a small portion of system N processing. Soil accumulation of N also played a minor role, leaving denitrification as the likely process responsible for the majority of system N processing. Based on a literature review, macrophyte species composition likely influences denitrification through oxygen diffusion into soils and through the quality and quantity of carbon in leaf litter. While this study and the literature indicates Typha spp. may be the best species to promote wetland N processing, other considerations (e.g., bird habitat) and conditions (e.g., type of wastewater being treated) likely make mixed stands of macrophytes preferable in many applications. Additionally, this study demonstrated the importance of urban wetlands as scientific laboratories for scientists of all ages and as excellent stepping-off points for experiments of science-policy discourse.

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Date Created
  • 2013-05

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Utilization of Passive Samplers for Water Quality Monitoring of Hexavalent Chromium in Water Treatment Plants

Description

The current EPA regulation for total chromium in drinking water is the MCL standard of 0.1 milligrams per liter or 100 parts per billion (ppb) to avoid dermatological effects. With

The current EPA regulation for total chromium in drinking water is the MCL standard of 0.1 milligrams per liter or 100 parts per billion (ppb) to avoid dermatological effects. With a toxicology study released in 2008 by the Department of Health and Human Services noting that hexavalent chromium is carcinogenic, the EPA is currently reviewing this MCL standard. During this review, the EPA provides monitoring guidance that requires quarterly sampling of surface water for hexavalent chromium. However, these samples monitor the instant in time that they were taken, and do not account for varying concentrations that are time-dependent. This research seeks to develop a method for monitoring hexavalent chromium in water. Using ion exchange technology, passive samplers were developed and installed at the Chandler Water Treatment Plant for a week-long monitoring event. Results show that passive samplers using ion exchange technology provide an accurate assessment of the average concentration of total chromium within the water treatment plant's effluent with 90.3% recovery of Cr(VI) in SIR-100 resin and 62.6% recovery in SIR-700.

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Date Created
  • 2014-05

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Health Implications of Impure Water Consumption and the Implementation and Outcome Analysis of Water Filters in Puerto Penasco, Sonora

Description

Consumption of clean, pathogen-free water is vital in maintaining health. The water infrastructure in Puerto Penasco, Sonora is not sufficient in providing clean water for its residents. Water in this

Consumption of clean, pathogen-free water is vital in maintaining health. The water infrastructure in Puerto Penasco, Sonora is not sufficient in providing clean water for its residents. Water in this region is being overdrafted, meaning it is distributed from deep wells faster than it can be regenerated, which prevents more wells from being constructed. There is a high need for a cost-efficient solution to the clean water shortage in this impoverished town. The purpose of this study was to determine: (1) how clean drinking water affects health, (2) how contaminated water and water substitutes, such as soda and juices, negatively impact health, and (3) the impact on water consumption by local residents after providing them with a portable filtration system to create clean drinking water in their own homes. Water filters were distributed in two trials to a convenience sample of 45 participants, 27 of whom were successfully contacted for a post-implementation survey. Out of the 27 participants who took the survey, 27% reported that they drank more water after receiving the filter than before, 40% reported drinking less soda after receiving the filter, 63% reported using their filter on a daily basis, 63% believed that drinking clean water is important for their health, and 74% thought that it was difficult for them to obtain clean drinking water before receiving the filter. Providing residents with a filtration system was effective in increasing water consumption and saving residents money on water but did not provide conclusive data, negating the use of soda as a water substitute. This was an effective small-scale solution to a much larger problem that may be beneficial in other similarly impoverished communities.

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Date Created
  • 2019-12

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Water quality and thermal stratification of Cragin Reservoir: current and future impact of forest fires

Description

C.C. Cragin Reservoir’s location in the Coconino National Forest, Arizona makes it prone to wild fire. This study focused on the potential impacts of such a wild fire on

C.C. Cragin Reservoir’s location in the Coconino National Forest, Arizona makes it prone to wild fire. This study focused on the potential impacts of such a wild fire on the reservoir’s annual thermal stratification cycle impacts and water quality. The annual thermal stratification cycle impacted the reservoir’s water quality by increasing hypolimnion concentrations of magnesium, iron, turbidity, and specific ultraviolet absorbance (SUVA) values, as well as resulting in the hypolimnion having decreased dissolved oxygen concentrations during stratified months. The scarification process did not affect the dissolved organic carbon (DOC) concentrations in the reservoir or the total/dissolved nitrogen and phosphorous concentrations. Some general water quality trends that emerged were that phosphorous was the limiting nutrient, secchi disk depth and chlorophyll a concentration are inversely related, and no metals were found to be in concentrations that would violate an EPA drinking water maximum contaminant level (MCL). A carbon mass model was developed and parameterized using DOC measurements, and then using historic reservoir storage and weather data, the model simulated DOC concentrations in the reservoir following four hypothetical wild fire events. The model simulated varying initial reservoir storage volumes, initial flush volumes, and flush DOC concentrations, resulting in reservoir DOC concentrations varying from 17.41 mg/L to 8.82 mg/L.

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Date Created
  • 2018

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Monitoring algal abundance and water quality in Arizona reservoirs through field sampling and remote sensing

Description

Safe, readily available, and reliable sources of water are an essential component of any municipality’s infrastructure. Phoenix, Arizona, a southwestern city, has among the highest per capita water use in

Safe, readily available, and reliable sources of water are an essential component of any municipality’s infrastructure. Phoenix, Arizona, a southwestern city, has among the highest per capita water use in the United States, making it essential to carefully manage its reservoirs. Generally, municipal water bodies are monitored through field sampling. However, this approach is limited spatially and temporally in addition to being costly. In this study, the application of remotely sensed reflectance data from Landsat 7’s Enhanced Thematic Mapper Plus (ETM+) and Landsat 8’s Operational Land Imager (OLI) along with data generated through field-sampling is used to gain a better understanding of the seasonal development of algal communities and levels of suspended particulates in the three main terminal reservoirs supplying water to the Phoenix metro area: Bartlett Lake, Lake Pleasant, and Saguaro Lake. Algal abundances, particularly the abundance of filamentous cyanobacteria, increased with warmer temperatures in all three reservoirs and reached the highest comparative abundance in Bartlett Lake. Prymnesiophytes (the class of algae to which the toxin-producing golden algae belong) tended to peak between June and August, with one notable peak occurring in Saguaro Lake in August 2017 during which time a fish-kill was observed. In the cooler months algal abundance was comparatively lower in all three lakes, with a more even distribution of abundance across algae classes. In-situ data from March 2017 to March 2018 were compared with algal communities sampled approximately ten years ago in each reservoir to understand any possible long-term changes. The findings show that the algal communities in the reservoirs are relatively stable, particularly those of the filamentous cyanobacteria, chlorophytes, and prymnesiophytes with some notable exceptions, such as the abundance of diatoms, which increased in Bartlett Lake and Lake Pleasant. When in-situ data were compared with Landsat-derived reflectance data, two-band combinations were found to be the best-estimators of chlorophyll-a concentration (as a proxy for algal biomass) and total suspended sediment concentration. The ratio of the reflectance value of the red band and the blue band produced reasonable estimates for the in-situ parameters in Bartlett Lake. The ratio of the reflectance value of the green band and the blue band produced reasonable estimates for the in-situ parameters in Saguaro Lake. However, even the best performing two-band algorithm did not produce any significant correlation between reflectance and in-situ data in Lake Pleasant. Overall, remotely-sensed observations can significantly improve our understanding of the water quality as measured by algae abundance and particulate loading in Arizona Reservoirs, especially when applied over long timescales.

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Date Created
  • 2018

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Comparative analysis of adsorptive media treatment for arsenic at SRP groundwater wells

Description

Arsenic (As) is a naturally occurring element that poses a health risk when continually consumed at levels exceeding the Environmental Protection Agencies (EPA) maximum contaminant level (MCL) of 10 ppb.

Arsenic (As) is a naturally occurring element that poses a health risk when continually consumed at levels exceeding the Environmental Protection Agencies (EPA) maximum contaminant level (MCL) of 10 ppb. With the Arizona Department of Water Resources considering reliance on other sources of water other than just solely surface water, groundwater proves a reliable, supplemental source. The Salt River Project (SRP) wants to effectively treat their noncompliance groundwater sources to meet EPA compliance. Rapid small-scale column tests (RSSCTs) of two SRP controlled groundwater wells along the Eastern Canal and Consolidated Canal were designed to assist SRP in selection and future design of full-scale packed bed adsorbent media. Main concerns for column choice is effectiveness, design space at groundwater wells, and simplicity. Two adsorbent media types were tested for effective treatment of As to below the MCL: a synthetic iron oxide, Bayoxide E33, and a strong base anion exchange resin, SBG-1. Both media have high affinity toward As and prove effective at treating As from these groundwater sources. Bayoxide E33 RSSCT performance indicated that As treatment lasted to near 60,000 bed volumes (BV) in both water sources and still showed As adsorption extending past this operation ranging from several months to a year. SBG-1 RSSCT performance indicated As, treatment lasted to 500 BV, with the added benefit of being regenerated. At 5%, 13%, and 25% brine regeneration concentrations, regeneration showed that 5% brine is effective, yet would complicate overall design and footprint. Bayoxide E33 was selected as the best adsorbent media for SRP use in full-scale columns at groundwater wells due to its simplistic design and high efficiency.

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Date Created
  • 2015

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Metal oxide nanoparticles in electrospun polymers and their fate in aqueous waste streams

Description

Nanotechnology is becoming increasingly present in our environment. Engineered nanoparticles (ENPs), defined as objects that measure less than 100 nanometers in at least one dimension, are being integrated into commercial

Nanotechnology is becoming increasingly present in our environment. Engineered nanoparticles (ENPs), defined as objects that measure less than 100 nanometers in at least one dimension, are being integrated into commercial products because of their small size, increased surface area, and quantum effects. These special properties have made ENPs antimicrobial agents in clothing and plastics, among other applications in industries such as pharmaceuticals, renewable energy, and prosthetics. This thesis incorporates investigations into both application of nanoparticles into polymers as well as implications of nanoparticle release into the environment. First, the integration of ENPs into polymer fibers via electrospinning was explored. Electrospinning uses an external electric field applied to a polymer solution to produce continuous fibers with large surface area and small volume, a quality which makes the fibers ideal for water and air purification purposes. Indium oxide and titanium dioxide nanoparticles were embedded in polyvinylpyrrolidone and polystyrene. Viscosity, critical voltage, and diameter of electrospun fibers were analyzed in order to determine the effects of nanoparticle integration into the polymers. Critical voltage and viscosity of solution increased at 5 wt% ENP concentration. Fiber morphology was not found to change significantly as a direct effect of ENP addition, but as an effect of increased viscosity and surface tension. These results indicate the possibility for seamless integration of ENPs into electrospun polymers. Implications of ENP release were investigated using phase distribution functional assays of nanoscale silver and silver sulfide, as well as photolysis experiments of nanoscale titanium dioxide to quantify hydroxyl radical production. Functional assays are a means of screening the relevant importance of multiple processes in the environmental fate and transport of ENPs. Four functional assays – water-soil, water-octanol, water-wastewater sludge and water-surfactant – were used to compare concentrations of silver sulfide ENPs (Ag2S-NP) and silver ENPs (AgNP) capped by four different coatings. The functional assays resulted in reproducible experiments which clearly showed variations between nanoparticle phase distributions; the findings may be a product of the effects of the different coatings of the ENPs used. In addition to phase distribution experiments, the production of hydroxyl radical (HO•) by nanoscale titanium dioxide (TiO2) under simulated solar irradiation was investigated. Hydroxyl radical are a short-lived, highly reactive species produced by solar radiation in aquatic environments that affect ecosystem function and degrades pollutants. HO• is produced by photolysis of TiO2 and nitrate (NO3-); these two species were used in photolysis experiments to compare the relative loads of hydroxyl radical which nanoscale TiO2 may add upon release to natural waters. Para-chlorobenzoic acid (pCBA) was used as a probe. Measured rates of pCBA oxidation in the presence of various concentrations of TiO2 nanoparticles and NO3- were utilized to calculate pseudo first order rate constants. Results indicate that, on a mass concentration basis in water, TiO2 produces hydroxyl radical steady state concentrations at 1.3 times more than the equivalent amount of NO3-; however, TiO2 concentrations are generally less than one order of magnitude lower than concentrations of NO3-. This has implications for natural waterways as the amount of nanoscale TiO2 released from consumer products into natural waterways increases in proportion to its use.

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Date Created
  • 2015

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The Conservation Reserve Program as a payments for water quality case study: an environmental economic analysis

Description

Payments for ecosystem services (PES) are transactions between landholders and the beneficiaries of the services their land provides. PES schemes are growing worldwide with annual transactions over ten billion dollars

Payments for ecosystem services (PES) are transactions between landholders and the beneficiaries of the services their land provides. PES schemes are growing worldwide with annual transactions over ten billion dollars (Salzman et al., 2018). Much can be learned from looking at oldest and best funded PES schemes on working agricultural land. Initiated in 1985, the USDA’s Conservation Reserve Program (CRP) is the oldest private conservation PES program in the United States. CRP incentivizes farmers to put their land into conservation through an annual payment. In Iowa, CRP has been a source of extra income and a way for farmers to buffer the fluctuating costs of cash crops, such as corn and soy. The dominance of agriculture in Iowa poses many challenges for water quality. A potential solution to the problem, implemented through CRP, is the use of conservation practices to mitigate the negative effects of agricultural run-off.

This dissertation considers three aspects of the problem:

1. the relationship between changes in land cover due to CRP enrollment and changes in water quality, controlling for a range of factors known to have an effect on the filtering role of different land covers;

2. the inter-annual variability in water quality measures and enrollment in different CRP conservation practices to examine the cost-effectiveness of specific conservation practices in mitigating lake sedimentation and eutrophication;

3. discrete choice models to identify what characteristics drive the enrollment by farmers into specific conservation practices.

Results indicate that land cover and CRP have different impacts on different indicators of lake water quality. In addition, conservation practices that were cost-effective for one water quality variable tended to be cost-effective for the other water quality variables. Farmers are making decisions to enroll in CRP based on the opportunity cost of the land. Therefore, it is necessary to alter financial incentives to promote productive land being putting into CRP through continuous sign-up. The United States Department of Agriculture (USDA) needs a more effective way to calculate the payment level for practices in order to be competitive with the predicted value of major crops.

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Date Created
  • 2019