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Role of Circular Economy in the Indigenous Built Environment: An Assessment of Design and Construction Potential of Circular Building Materials in an American Indian Community

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This thesis intends to help inform American Indian nations’ decision making related to housing. The study recognizes the urgent need for housing solutions that fit the needs of a community as well as benefit the overall ecosystem. One model that can offer guidance is the Circular Economy (CE) model. A…

This thesis intends to help inform American Indian nations’ decision making related to housing. The study recognizes the urgent need for housing solutions that fit the needs of a community as well as benefit the overall ecosystem. One model that can offer guidance is the Circular Economy (CE) model. A well-thought-out CE process can provide housing solutions that are economically, socially, and environmentally sustainable. It also stimulates the local economy by strategically introducing positive changes. This research identifies the construction potential of available circular materials as compared to more contemporary building materials. It then recommends a closed-loop circular model that utilizes the community’s existing infrastructure to develop affordable housing. The proposed CE model operates within the built environment, stimulating local employment while catering to the needs of the residents. Such an approach can prove to be beneficial for the local community and perhaps scalable to the global economy.
ContributorsPatadia, Niti Arshey (Author) / El Asmar, Mounir (Thesis advisor) / Begay Jr., Richard K (Committee member) / Horton, Philip (Committee member) / Neveu, Marc (Committee member) / Arizona State University (Publisher)
Created2020
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Production of Renewable Fuels from Bio-Based Feedstocks: A Viable Path to Enhance Value Chain and Sustainability

Description
The continued reliance on fossil fuel for energy resources has proven to be unsustainable, leading to depletion of world reserves and emission of greenhouse gases during their combustion. Therefore, research initiatives to develop potentially carbon-neutral biofuels were given the highest importance. Hydrothermal liquefaction (HTL, a thermochemical conversion process) of microalgae…

The continued reliance on fossil fuel for energy resources has proven to be unsustainable, leading to depletion of world reserves and emission of greenhouse gases during their combustion. Therefore, research initiatives to develop potentially carbon-neutral biofuels were given the highest importance. Hydrothermal liquefaction (HTL, a thermochemical conversion process) of microalgae is recognized as a favorable and efficient technique to produce liquid biofuels from wet feedstocks. In this work, three different microalgae (Kirchneriella sp., Galdieria sulphuraria, Micractinium sp.) grown and harvested at Arizona State University were hydrothermally liquefied to optimize their process conditions under different temperatures (200-375 °C), residence times (15-60 min), solids loadings (10-20 wt.%), and process pressures (9-24 MPa). A one-factor-at-a-time approach was employed, and comprehensive experiments were conducted at 10 % solid loadings and a residence time of 30 min. Co-liquefaction of Salicornia bigelovii Torr. (SL), Swine manure (SM) with Cyanidioschyzon merolae (CM) was tested for the presence of synergy. A positive synergistic effect was observed during the co-liquefaction of biomasses, where the experimental yield (32.95 wt.%) of biocrude oil was higher than the expected value (29.23 wt.% ). Co-liquefaction also led to an increase in the energy content of the co-liquefied biocrude oil and a higher energy recovery rate ( 88.55 %). The HTL biocrude was measured for energy content, elemental, and chemical composition using GC-MS. HTL aqueous phase was analyzed for potential co-products by spectrophotometric techniques and is rich in soluble carbohydrates, dissolved ammoniacal nitrogen, and phosphates. HTL biochar was studied for its nutrient content (nitrogen and phosphorous) and viability of its recovery to cultivate algae without any inhibition using the nutrient leaching. HTL biochar was also studied to produce hydrogen via pyrolysis using a membrane reactor at 500 °C, 1 atm, for 24 h to produce 5.93 wt.% gas. The gaseous product contains 45.7 mol % H2, 44.05 ml % CH4, and 10.25 mol % of CO. The versatile applications of HTL biochar were proposed from a detailed physicochemical characterization. The metal impurities in the algae, bio-oil, and biochar were quantified by ICP-OES where algae and biochar contain a large proportion of phosphorous and magnesium.
ContributorsDandamudi, Kodanda Phani Raj (Author) / Deng, Shuguang (Thesis advisor) / Lammers, Peter J. (Committee member) / Fini, Elham H. (Committee member) / Lind Thomas, MaryLaura (Committee member) / Varman, Arul M. (Committee member) / Arizona State University (Publisher)
Created2020