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- All Subjects: Phosphorus
- Creators: Blair, Antonio
- Creators: Childers, Daniel
Description
Phosphorus (P), an essential element for life, is becoming increasingly scarce, and its global management presents a serious challenge. As urban environments dominate the landscape, we need to elucidate how P cycles in urban ecosystems to better understand how cities contribute to — and provide opportunities to solve — problems of P management. The goal of my research was to increase our understanding of urban P cycling in the context of urban resource management through analysis of existing ecological and socio-economic data supplemented with expert interviews in order to facilitate a transition to sustainable P management. Study objectives were to: I) Quantify and map P stocks and flows in the Phoenix metropolitan area and analyze the drivers of spatial distribution and dynamics of P flows; II) examine changes in P-flow dynamics at the urban agricultural interface (UAI), and the drivers of those changes, between 1978 and 2008; III) compare the UAI's average annual P budget to the global agricultural P budget; and IV) explore opportunities for more sustainable P management in Phoenix. Results showed that Phoenix is a sink for P, and that agriculture played a primary role in the dynamics of P cycling. Internal P dynamics at the UAI shifted over the 30-year study period, with alfalfa replacing cotton as the main locus of agricultural P cycling. Results also suggest that the extent of P recycling in Phoenix is proportionally larger than comparable estimates available at the global scale due to the biophysical characteristics of the region and the proximity of various land uses. Uncertainty remains about the effectiveness of current recycling strategies and about best management strategies for the future because we do not have sufficient data to use as basis for evaluation and decision-making. By working in collaboration with practitioners, researchers can overcome some of these data limitations to develop a deeper understanding of the complexities of P dynamics and the range of options available to sustainably manage P. There is also a need to better connect P management with that of other resources, notably water and other nutrients, in order to sustainably manage cities.
ContributorsMetson, Genevieve (Author) / Childers, Daniel (Thesis advisor) / Aggarwal, Rimjhim (Thesis advisor) / Redman, Charles (Committee member) / Arizona State University (Publisher)
Created2011
DescriptionThis project focuses on how best management practices impact the phosphorus and nitrogen concentrations in water bodies all across the United States. Both chemical and biological indicators were analyzed.
ContributorsBaker, Kayla (Author) / Blair, Antonio (Co-author) / Kumar, Saurav (Thesis director) / Johnson, Abbey (Committee member) / Weiss, Josh (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainable Engineering & Built Envirnmt (Contributor)
Created2024-05
Description
Best Management Practices (BMPs) are often designed to restore the water quality of impaired waterbodies. They are expensive to install and maintain and often have limited post-installation analysis. There is a gap in our knowledge of the long-term real-world efficiency of such systems as their dynamics are complex and poorly understood, and we have very limited data about these systems. We looked at water quality changes pre- and post-BMP implementation from sites around the US to better understand the impacts of BMPs on the nitrogen (N) and phosphorus (P) concentrations in the waterbodies. Water quality data was obtained from 72 waterbodies across the United States using the National Water Quality Monitoring Council’s Water Quality Portal. This data was analyzed for trends using the Kaplan-Meier method, exceedance probability, and lag time analysis. Out of the seventy-two (72) watershed locations, twenty-two (22) did not have enough data for analysis. Of these fifty (50) remaining watersheds locations one hundred eighty-four (184) monitoring sites were analyzed. Only sixty-nine (69) of these monitoring sites were found to have enough data for analysis. Forty-eight (48) sites saw improvement in nutrient levels, where overall post-implementation exceedance probability for critical thresholds (defined as 1 mg/l for N and 0.1 mg/l for P) decreased. Twenty-one (21) sites did not see improvement, where post-implementation exceedance probabilities did not show any reduction; in some cases, it showed an increase. Even among the efficient sites, where improvement was found, significant variation was observed in changes in exceedance probability with time, with many sites not demonstrating an expected uniform decreasing trend. It was also found that 56 out of the 72 water bodies had some biological indicator present, these included dissolved oxygen concentrations, benthic macroinvertebrate populations, fish communities/aquatic life, bacteria, and index scores. However, data gaps were detrimental to conclusively assessing BMPs with biological indicators. It was determined that sparse biological indicators data were not indicative of BMP success. These observations highlight the importance of designing a monitoring strategy that can capture these unexpected trends and allow a better understanding of BMPs. Along with better monitoring strategies, consistent and frequent monitoring is needed. Therefore, the effectiveness of best management practices was inconclusive due to a lack of available data on many sites.
ContributorsBlair, Antonio (Author) / Baker, Kayla (Co-author) / Kumar, Saurav (Thesis director) / Weiss, Josh (Committee member) / Johnson, Abbey (Committee member) / Barrett, The Honors College (Contributor) / Civil, Environmental and Sustainable Eng Program (Contributor)
Created2024-05
Description
Phosphorus (P) is an essential resource for global food security, but global supplies are limited and demand is growing. Demand reductions are critical for achieving P sustainability, but recovery and re-use is also required. Wastewater treatment plants and livestock manures receive considerable attention for their P content, but municipal organic waste is another important source of P to address. Previous research identified the importance of diverting this waste stream from landfills for recovering P, but little has been done to identify the collection and processing mechanisms required, or address the existing economic barriers. In my research, I conducted a current state assessment of organic waste management by creating case studies in Phoenix, Arizona and New Delhi, India, and surveyed biomass energy facilities throughout the United States. With participation from waste management professionals I also envisioned an organic waste management system that contributes to sustainable P while improving environmental, social, and economic outcomes.
The results of my research indicated a number of important leverage points, including landfill fees, diversion mandates for organic waste, and renewable energy credits. Source separation of organic waste improves the range of uses, decreases processing costs, and facilitates P recovery, while creating jobs and contributing to a circular economy. Food is a significant component of the waste stream, and edible food is best diverted to food banks, while scraps are best given to livestock. Biomass energy systems produce multiple revenue streams, have high processing capacities, and concentrate P and other minerals to a greater extent than composting. Using recovered P in urban agriculture and native landscaping results in additional benefits to social-ecological systems by improving food security, reducing the urban heat island effect, sequestering carbon, and enhancing urban ecosystems.
The results of my research indicated a number of important leverage points, including landfill fees, diversion mandates for organic waste, and renewable energy credits. Source separation of organic waste improves the range of uses, decreases processing costs, and facilitates P recovery, while creating jobs and contributing to a circular economy. Food is a significant component of the waste stream, and edible food is best diverted to food banks, while scraps are best given to livestock. Biomass energy systems produce multiple revenue streams, have high processing capacities, and concentrate P and other minerals to a greater extent than composting. Using recovered P in urban agriculture and native landscaping results in additional benefits to social-ecological systems by improving food security, reducing the urban heat island effect, sequestering carbon, and enhancing urban ecosystems.
ContributorsStoltzfus, Jared Thomas Yoder (Author) / Childers, Daniel (Thesis advisor) / Basile, George (Committee member) / Abbott, Joshua (Committee member) / Arizona State University (Publisher)
Created2016