Date of Award
Master of Science (MS)
Environmental Engineering and Earth Science
The use of low-pressure, hollow fiber microfiltration (MF) and ultrafiltration (UF) membranes has become increasingly prominent in drinking water treatment plant configurations over the past 30 years. At the same time, the topics of energy efficiency and sustainability in industry are becoming progressively more important. Although MF and UF are highly successful in filtration, they are generally thought of as significant energy consumers; however, the data have not yet been available to compare multiple plants in various contexts to determine the factors that most affect energy use. This research compares the energy use of MF and UF treatment plants to conventional granular media filtration treatment plants to recommend opportunities to decrease overall plant energy consumption.
The average energy use for granular media filtration (GMF), MF, and UF water treatment plants was determined to be 1.05 kWh/kgal, or 0.28 kWh/m3, with small plants having the highest and lowest normalized energy use ranging from 0.02 to 2.15 kWh/kgal. Raw water characteristics and operational differences did not have significant effects on overall plant energy use in this data set, though temperature and membrane configuration data provided motivation for further analysis. A series of statistical analyses, including a series of t-tests, an analysis of variance (ANOVA) test and a main effects model concluded that the small data set, comprised of only 14 treatment plants, does not provide enough data to produce robust analytical results to accurately predict energy use for a specific unit process or an entire facility. In addition to statistical tests, a first principles calculation of predicted energy use was effective in explaining 83% of the variability in energy use at the plants. This successfully shows that the bulk of energy use is due to the unit processes analyzed.
To decrease cumulative energy demand and environmental effects, a life cycle assessment (LCA) concluded that decreasing the backwash frequency for MF/UF and GMF plants as well as decreasing clean in place (CIP) frequency for MF/UF plants will decrease energy demand, ecotoxicity, and global warming potential.
Larsen, Danielle, "An Evaluation of Energy Consumption Comparing Conventional Water Treatment Plants to Microfiltration and Ultrafiltration Water Treatment Plants" (2022). All Theses. 3843.