Date of Award

12-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Environmental Engineering and Earth Science

Advisor

Lee, Cindy M

Committee Member

Miller , Shellie

Committee Member

Schlautman , Mark

Abstract

Wastewater treatment is an essential part of life in the urbanized world. As global climate change becomes a more pressing issue, the greenhouse gas emissions created through wastewater treatment will become a more prominent concern. Tertiary treatment will likely be standard for wastewater treatment plants in the near future, and therefore must be included in a model of greenhouse gas emissions. Also, the geographic location of a WWTP will change the mix of power types (e.g., coal, nuclear, biomass) used to run the plant. Although GHG emissions from the waste sector are small compared to the emissions of the United States as a whole, they should still be managed and reduced. CO2e-WWTP, the model produced, is based largely on the work of Monteith et al. (2005) and was written using Visual Basic within Microsoft Excel to allow for a simple user interface. Modifications included removing a fitting factor for solids, generating a method for estimating the amount of nitrous oxide produced, and allowing for the calculation of greenhouse gas emissions from power from different sources. Eleven wastewater treatment plants, having capacities of 0.5 to 2.5 million gallons per day, were modeled for emissions of carbon dioxide, methane, and nitrous oxide. The plants were modeled with their current treatment systems and with the addition of tertiary treatment such as activated carbon, rapid sandfiltration, and an activated lagoon/wetland. The average carbon dioxide equivalent emissions for the treatment processes were found to be 0.410 g/L. It was found that in conventional wastewater treatment systems that nitrous oxide production does not contribute significantly to overall greenhouse gas emissions (about 2-4% of carbon dioxide equivalent emissions), however, when solids treatment is considered nitrous oxide emissions are a more significant contribution (about 4-13% of carbon dioxide equivalent emissions). Several of the power sources created GHG emissions that were statistically different from the other power sources found through the use of an ANOVA. Greenhouse gas emissions from wastewater treatment processes and plants can vary greatly depending on the processes employed which is why CO2e-WWTP is a valuable tool for those both in academia and the wastewater treatment field. However, more field research into wastewater treatment and its mechanisms for producing GHG emissions needs to be done.
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CO2eWWTP.xlsm (109 kB)

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