DEVELOPMENT AND APPLICATION OF A PARTICLE-TRACKING MODEL FOR NITROGEN TRANSPORT AND TRANSFORMATION IN AQUIFERS
dc.contributor.advisor | Welty, Claire | |
dc.contributor.author | Cui, Zhengtao | |
dc.contributor.department | Chemical, Biochemical & Environmental Engineering | |
dc.contributor.program | Engineering, Civil and Environmental | |
dc.date.accessioned | 2019-10-11T12:34:59Z | |
dc.date.available | 2019-10-11T12:34:59Z | |
dc.date.issued | 2015-01-01 | |
dc.description.abstract | This work focuses on quantifying reactive groundwater nitrogen transport through development and application of a new numerical model. I first developed the model "SF Monod" to incorporate multispecies biodegradation and geochemical reactions into an existing particle-tracking code to simulate reactive transport in three-dimensional variably saturated media, with a focus on nitrification and denitrification processes. Biogeochemical reactions are modeled using Monod kinetics; reactive air-phase transport is included so that gases such as nitrogen gas can be tracked. I verified the new code by showing good agreement with analytical solutions, other numerical codes, and laboratory observations. I demonstrated model capability to track sharp fronts by simulating a leaking sewer plume in heterogeneous variably saturated media. In the second part of the work I demonstrated application of the SF Monod model to strategically design placement of woodchip bioreactors for step-pool and channel re-meandering stream restoration scenarios. With only 50% and 53% of full-reach design lengths, the strategically designed bioreactors achieve about 65% and 85% the performance of the original design for the step-pool and channel re-meandering scenarios, respectively, as well as maximum denitrification efficiencies. These results suggest that shorter bioreactors can be installed while still achieving the goal of the restoration project. This work represents a first application of a multispecies reactive transport code to stream restoration design. In the third part of this work, I used the SF Monod model to quantify transport of subsurface nitrogen from septic contamination to a stream network at a Piedmont catchment. I evaluated spatial and temporal distribution of nitrate concentration and denitrification rates, as well as the nitrate concentrations and flux at the groundwater-stream interface. Although the modeled catchment is small and represented by only one kind of contamination (multiple 50- to 60-year-old septic tanks in a 0.23 km2 watershed), the model can be applied to any scale. Because it is particle-tracking based, relatively low spatial resolution can be used for watershed-scale simulations. To my knowledge, no previous efforts have been made to quantify subsurface transport of nitrogen to receiving water bodies at watershed scale using a three-dimensional multispecies reactive transport model that considers biomass metabolism. | |
dc.genre | dissertations | |
dc.identifier | doi:10.13016/m2upzs-pbkp | |
dc.identifier.other | 11358 | |
dc.identifier.uri | http://hdl.handle.net/11603/15070 | |
dc.language | en | |
dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
dc.relation.ispartof | UMBC Chemical, Biochemical & Environmental Engineering Department Collection | |
dc.relation.ispartof | UMBC Theses and Dissertations Collection | |
dc.relation.ispartof | UMBC Graduate School Collection | |
dc.relation.ispartof | UMBC Student Collection | |
dc.rights | This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. For permission to publish or reproduce, please see http://aok.lib.umbc.edu/specoll/repro.php or contact Special Collections at speccoll(at)umbc.edu | |
dc.source | Original File Name: Cui_umbc_0434D_11358.pdf | |
dc.subject | denitrification | |
dc.subject | denitrification bioreactor | |
dc.subject | nitrogen contamination | |
dc.subject | reactive groundwater transport | |
dc.subject | stream restoration | |
dc.subject | watershed nitruent transport | |
dc.title | DEVELOPMENT AND APPLICATION OF A PARTICLE-TRACKING MODEL FOR NITROGEN TRANSPORT AND TRANSFORMATION IN AQUIFERS | |
dc.type | Text | |
dcterms.accessRights | Distribution Rights granted to UMBC by the author. |