MnDOT is responsible for 52 safety rest areas and truck stations across Minnesota served by septic systems. Managing these septic systems is a critical activity of MnDOT and a better understanding of the functionality and treatment of these systems is critical. This proposal is a follow up a three-year project completed in 2019 between the University of Minnesota (UM) and the Minnesota Department of Transportation (MnDOT). The first project will continue field-based verification of groundwater mounding to estimate the influence of larger wastewater treatment systems on groundwater systems. This information will assist MnDOT in prioritizing upgrades. One rest area will be studied in depth to determine the nitrogen related microbial community after the influence of installation a new system with and without pretreatment for nitrogen. This information can be used to better understand nitrogen treatment in soil treatment areas. Five rest areas and one land application site will be evaluated to determine the fate and transport of chemical of emerging concern (CEC) from wastewater. CECs are an emerging wastewater issue and gaining more information will assist MnDOT in managing the issue. This project will also develop a large artistic education display for Fuller Lake Rest Area to education the public about the positive environmental work of MnDOT.