Department or Program

Environmental Studies

Abstract

Hot dry rock geothermal power plants are an emerging technology within the renewable energy sector, yet there remains a need to investigate the possibility of using circulating fluids that may replace the conventional, environmentally-valuable freshwater resource. This study investigates the use of domestic wastewater types in the operation of this system by analyzing their heat exchange in the reservoir rock, preheater, and evaporator, potential for corrosion and scaling damage, and environmental concerns relative to freshwater. Through a series of literature and thermodynamic equations, a methodology was created to evaluate domestic wastewater in these respects – one that may be used to evaluate other fluids like municipal wastewater or seawater. After careful procedure, it was concluded that both untreated influent and treated effluent were likely to exchange heat less efficiently in the reservoir than freshwater, but as efficiently in the preheater and evaporator. In addition, untreated influent is predicted to have a higher risk of scaling and corrosion damage than both freshwater and treated effluent that seem to perform similarly. Finally, all three fluid types were deemed to have similar environmental concerns. For both wastewater types, systems would need to include higher fluid pressures, larger volumes, and/or corrosion-resistant materials before they may be adopted into a hot dry rock power plant. However, paired with these technological advancements, domestic wastewater could be a reliable resource for their operation in the future.

Level of Access

Restricted: Campus/Bates Community Only Access

First Advisor

Holly Ewing

Date of Graduation

5-2023

Degree Name

Bachelor of Science

Number of Pages

68

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Available to Bates community via local IP address or Bates login.

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