Groundwater quality impacts from a full-scale integrated constructed wetland

Dzakpasu, D; Scholz, M; Harrington, R; McCarthy, V; Jordan, S

Abstract

The concept of integrated constructed wetlands (ICW) promotes in-situ soils to construct and line wetland cells. The integrity of soil
material, however, may provide a potential pathway for contaminants to flow into the underlying groundwater. This study assessed the extent
of groundwater quality deterioration due to the establishment of a full-scale ICW system treating domestic wastewater in Ireland. The ICW
is located at Glaslough in Co. Monaghan, Ireland. It consists of two sedimentation ponds and a sequence of five shallow vegetated wetland
cells. The ICW cells were lined with 500-mm thick local subsoil material, which comprised a mixture of alluvium, organic soils, tills, and gravel.
Groundwater samples and head data were collected from eight piezometers, which were installed around the ICW cells. The groundwater and
wetland water samples were analysed for water quality parameters such as bulk organic matter, nutrients, and pathogens. Overall, the quality
of groundwater underlying the ICW system recorded some contamination with bulk organic matter and some inorganic nutrients. Significantly
higher contaminant concentrations were recorded in monitoring wells upgradient and near to the distal wetland cells than downgradient ones,
which were near to the proximal cells. For the downgradient piezometers, concentrations seldomly exceeded the natural background levels.
Detailed analyses through the application of chemometrics models indicated that the source of contamination was largely of geogenic origin.
Findings suggest that ICW systems pose a minimal risk to the groundwater quality; the greatest risk was associated with the distal wetland
cells.

Citation

Dzakpasu, D., Scholz, M., Harrington, R., McCarthy, V., & Jordan, S. (2014). Groundwater quality impacts from a full-scale integrated constructed wetland. Ground Water Monitoring and Remediation, 34(3), 51-64. https://doi.org/10.1111/gwmr.12059

• Journal Article Type: Article
• Online Publication Date: Jun 6, 2014
• Publication Date: Aug 25, 2014
• Deposit Date: Nov 7, 2014
• Publicly Available Date: Apr 5, 2016
• Journal: Groundwater Monitoring & Remediation
• Print ISSN: 1069-3629
• Electronic ISSN: 1745-6592
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 34
• Issue: 3
• Pages: 51-64
• DOI: https://doi.org/10.1111/gwmr.12059
• Publisher URL: http://onlinelibrary.wiley.com/doi/10.1111/gwmr.12059/abstract
• Related Public URLs: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1745-6592
• Additional Information: Projects : Integrated Constructed Wetlands to Treat Domestic Wastewater: Performance, Processes and Implications for Groundwater