Graduation Year

2015

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

James R. Mihelcic, Ph.D.

Co-Major Professor

Qiong Zhang, Ph.D.

Committee Member

David Bracciano, M.P.A

Committee Member

Jeffrey Cunningham, Ph.D.

Committee Member

Tapas Das, Ph.D.

Keywords

sustainability, water, life cycle assessment, urban planning, climate, smart growth

Abstract

Increasing urbanization has serious implications for resource and energy use. One of these resources is drinking water. The increased amount of impervious surfaces associated with urban development is responsible for increased runoff during rain events, which may have a negative impact on the quality of nearby bodies of water, including drinking water sources. The growing populations associated with urbanization require a higher water demand. In addition, urban drinking water systems use energy to collect, treat, and distribute a safe reliable effluent to users. Therefore, this study focuses on the degree to which urbanization influences the embodied energy of drinking water in the city of Tampa via three objectives: (1) determine the degree to which the embodied energy of drinking water treatment is influenced by water quality possibly caused by urbanization, (2) determine the influence of urban form on the embodied energy of water supply, and (3) determine the effect of the state of water infrastructure on the embodied energy of drinking water.

The influence of the water quality of the Hillsborough River Reservoir on the embodied energy of drinking water at the David L. Tippin Water Treatment Facility was determined and quantified via statistical analysis methods and life cycle energy analysis. Results show that energy due to electricity and fuel use (direct energy) is responsible for 63% of the embodied energy of drinking water treatment in the city of Tampa. However, the 37% of energy due to treatment chemical usage (indirect energy) is substantial and most influenced by influent water quality. Two constituents, total organic carbon and conductivity, are responsible for influencing 14.5% of Tampa’s drinking water treatment embodied energy.

The effect of smart growth on the embodied energy of water supply was studied via the comparison of four future development scenarios within the Tampa WSA. The water consumption was estimated for each scenario and integrated into EPANET, a water distribution modeling software. After running each scenario, the embodied energy was calculated. The smart growth scenarios had 1-4% higher embodied energies than the business-as-usual scenario (urban sprawl). This was due to the location of added demand relative to the location of the water treatment facility. Nevertheless, while smart growth does not inherently minimize the embodied energy of water supply, it can result in the minimization of per capita water use due to the addition of more multi-family homes.

About 16 pipe replacement scenarios were used to determine the degree to which the state of water infrastructure affects drinking water supply embodied energy. These scenarios were simulated using EPANET. The replacement of all pipes in the city of Tampa is estimated to result in an embodied energy decrease of about 20%. However, taking into account the energy use associated with pipe installation, only replacement of pipes that are older than 20 years with recycled ductile iron yields a net energy savings.

The results of these studies show the influence of the roles that influent water quality, future urban development and infrastructure condition play on the embodied energy of drinking water in the Tampa WSA. However, future studies could look more in depth into these relationships via more definitive studies on the effect of land use on the Hillsborough River, and expanding the future development scenario studies to the metropolitan scale.

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