Research Article Open Access

Preliminary Evaluation of a Permeable Reactive Barrier for Reducing Groundwater Nitrate Transport from a Large Onsite Wastewater System

Charles Humphrey1, Sushama Pradhan2, Eban Bean1, Michael O’Driscoll1 and Guy Iverson1
  • 1 East Carolina University, United States
  • 2 , United States

Abstract

A permeable reactive barrier was installed between a large Onsite Wastewater System (OWS) and a monitoring well located down-gradient from the OWS. Groundwater samples from the well had shown elevated and increasing concentrations of NO3--N (>20 mg L-1 for 2 years). The barrier was constructed using woodchips from various tree species that were placed in a trench excavated to approximately the same depth as the well which was experiencing elevated NO3--N concentrations. Groundwater samples (5) were collected from the well between two weeks and four months after the barrier was installed. Groundwater NO3--N concentrations dropped by an average of 5 mg L-1, while Dissolved Organic Carbon (DOC) concentrations increased by 11 mg L-1 and Cl concentrations stayed relatively stable (<2 mg L-1 increase). The data suggest that denitrification fueled by the DOC from the barrier may be contributing to the lower NO3--N concentrations. Monitoring will continue at the site to determine the longer-term water quality trends. More research should be conducted to evaluate the applicability of permeable barriers as a best management practice for non-point sources of pollution in nutrient sensitive areas.

American Journal of Environmental Sciences
Volume 11 No. 4, 2015, 216-226

DOI: https://doi.org/10.3844/ajessp.2015.216.226

Submitted On: 31 March 2015 Published On: 25 August 2015

How to Cite: Humphrey, C., Pradhan, S., Bean, E., O’Driscoll, M. & Iverson, G. (2015). Preliminary Evaluation of a Permeable Reactive Barrier for Reducing Groundwater Nitrate Transport from a Large Onsite Wastewater System. American Journal of Environmental Sciences, 11(4), 216-226. https://doi.org/10.3844/ajessp.2015.216.226

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Keywords

  • Nitrogen
  • Onsite
  • Wastewater
  • Permeable Barrier