Septic System Evaluation at MnDOT Rest Stops and Truck Garages

Principal Investigator:

Sara Heger


Project Summary:

There is little information available on the 51 septic systems serving the rest stops and truck garages across Minnesota at MnDOT facilities. Many of these systems are more than 30 years old, and the lack of information makes managing them, prioritizing replacement, and designing replacement systems very difficult. It is generally understood that these systems are subject to challenging site conditions and wastewater characteristics. Better data are needed to ensure the systems are adequately treating wastewater and will continue to over the long term.

This project will first develop a protocol for system assessment and then implement the assessment on five sites. The assessment will include evaluating the current system components, identifying any deficiencies, and providing recommendations for improvements, if needed. Initial grab sampling of wastewater characteristics including flow and effluent quality will be obtained, if accessible, and a sampling protocol developed for the system operator. The first eight sites evaluated will help develop a risk-based assessment model focusing on site and wastewater characteristics specifically for the MnDOT sites. The remaining 46 sites will be evaluated based on the procedures developed and prioritized based on the risk-based assessment model.


Project Details:

  • Start date: 01/2013
  • Project Status: Completed
  • Research Area: Environment and Energy
  • Topics: Environment, Maintenance