Biological Nitrate Removal With Emerald Ash Borer-Killed Ash and High-Tannin Oak Woodchips

Niranga M. Wickramarathne, Laura E. Christianson, Mary E. Foltz, Julie L. Zilles, Reid D. Christianson, Richard A.C. Cooke

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Two common tree species, ash (Fraxinus sp.) and oak (Quercus sp.), could provide readily available media for denitrifying bioreactors that use wood-based carbon for biological nitrate treatment. However, it is not known if the wood from Emerald Ash Borer-killed (EAB-killed) ash trees is an effective carbon source for nitrate removal compared to other wood species or if the high-tannin nature of oak inhibits denitrification potential. This lab-scale study showed that EAB-killed ash woodchips did not significantly differ in nitrate removal or denitrification potential compared to a commercially available blend of hardwood chips. However, neither treatment performed as well as oak woodchips in these metrics. Use of high-tannin oak in bioreactors is currently restricted by a federal standard in the United States. Ash woodchips beneficially exhibited the lowest nitrous oxide production potential, and their dissolved phosphorus leaching fell within the range of other woodchip types. Emerald ash borer-killed ash wood could be an effective source for denitrifying bioreactors located within affected regions and oak woodchips merit additional investigation for the application of denitrifying bioreactors.

Original languageEnglish (US)
Article number648393
JournalFrontiers in Environmental Science
StatePublished - Mar 17 2021
Externally publishedYes

Bibliographical note

Funding Information:
NW performed the bioreactor flow-through experiment, provided initial data analysis, wrote the original draft, and assisted with editing. MF performed the DEAs, analyzed and wrote the DEA results, received funding for this work through graduate student grants, and assisted with editing. JZ assisted with methodology, data validation, and editing, and supervised MF. RDC generated the GIS data and map as well as edited the drafts. RAC conceptualized the experiment and provided supervision, data validation, and editing. LC provided funding acquisition, formal data analysis, project administration, supervision (of NW), and led the editing and submission process. All authors contributed to the article and approved the submitted version.

Funding Information:
We acknowledge Mr. Jay Hayek, University of Illinois Extension Forester, who helped source the wood media. Funding. The authors acknowledge funding from project NR185A12XXXXC004 CESU under the Great Rivers Umbrella Agreement 68-3A75-18-518 504 (USDA NRCS); the Illinois Water Resources Center project #G16AP00051; and the Agriculture and Food Research Initiative program priority area of Renewable Energy, Natural Resources and Environment from the USDA National Institute of Food and Agriculture (grant no. 2018-67011-28071/project accession no. 1015478). Some equipment was supplied via university extension Smith-Lever funds. The funders had no involvement in the study design, data collection or analysis, or manuscript writing.

Publisher Copyright:
© Copyright © 2021 Wickramarathne, Christianson, Foltz, Zilles, Christianson and Cooke.


  • ash (Fraxinus sp.)
  • bioreactor
  • denitrification
  • denitrification potential
  • nitrate
  • oak (Quercus sp.)


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