W3 Seminar: Numerical estimation of nitrogen loading from septic systems to surface waterbodies

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Numerical estimation of nitrogen loading from septic systems to surface waterbodies

Ming Ye, Professor, Department of Earth, Ocean and Atmospheric Science, Florida State University

Abstract: Nitrogen pollution is one of the most prevalent and challenging environmental problems worldwide. Treatment of domestic wastewater using onsite sewage treatment and disposal systems (a.k.a. septic systems) is considered as the second largest nitrogen source in Florida. For managing nitrogen pollution due to septic systems, we developed software, called ArcGIS-based Nitrogen Load Estimation Toolkit (ArcNLET) for simulating nitrogen transport in soil and groundwater and for estimate nitrogen loading from septic systems to surface waterbodies. ArcNLET first simulates one-dimensional unsaturated flow and reactive transport of ammonium and nitrate in soil between drainfields and water table, and then simulates two-dimensional groundwater flow and reactive transport of ammonium and nitrate in groundwater. ArcNLET is an easy-to-use computer tool, and can be used to estimate long-term nitrogen loading from septic systems to surface water bodies to support management of nitrogen pollution. This seminar will first present the groundwater flow and solute transport models behind ArcNLET, and then introduce several applications of ArcNLET at several study site across the state, including a recent application for estimating the relations between nitrogen attenuation rates and distances from septic systems to water table and surface waterbodies. We recently developed the Python version of ArcNLET for ArcGIS Pro, and the source codes and user manual are available at GitHub (https://github.com/ArcNLET-Py/ArcNLET-Py) for free download.