Suitability of three wood species for denitrification bioreactor fill

Laura Elizabeth Christianson, J. A. Hanly, M. J. Hedley

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

As a relatively new technology to mitigate nitrate (NO3-) losses in agricultural drainage water, denitrification bioreactors can take advantage of locally available carbon sources, otherwise considered waste, to address a water quality problem. This work compared the potential of three widespread, on-farm tree species in New Zealand to serve as woodchip denitrification bioreactor fill to treat pastoral drainage waters. A batch experiment tested woodchips made from three tree species, willow (Salix matsudana), pine (Pinus radiataj and cypress (Cupressus lusitanica), each with or without leaves/needles and either fresh or field-aged, and further column testing was done with two particle size ranges of pine and willow chips at four retention times. All species were able to remove NO3- in both tests with removal rates averaging 1.5-6.6 g N/day/m3 during column testing. However, willow was not recommended due to high and more sustained releases of ammonium. Woodchip carbon materials with a relatively large proportion of fines (< 2 mm particle size) and low C:N should be avoided as bioreactor fill due to poorer NO3- removal and potential for nitrogen loss. Although inclusion of green foliage materials in this short-term work did not consistently effect NO3- removal or ammonium losses, treatments that included needles had poor particle size uniformity. This would potentially allow greater compaction and altered hydraulic conductivity over time as well as having lower C:N than aged media, which may exacerbate nitrogen leaching concerns. Using field-aged woody media can help avoid these issues. This work illustrates the potential of denitrification bioreactors for NO3- reduction in pastoral drainage waters, though longer-term and larger-scale studies are needed.

Original languageEnglish (US)
Title of host publicationAmerican Society of Agricultural and Biological Engineers Annual International Meeting 2014, ASABE 2014
PublisherAmerican Society of Agricultural and Biological Engineers
Pages1447-1457
Number of pages11
Volume2
ISBN (Electronic)9781632668455
StatePublished - 2014
Externally publishedYes
EventAmerican Society of Agricultural and Biological Engineers Annual International Meeting 2014, ASABE 2014 - Montreal, Canada
Duration: Jul 13 2014Jul 16 2014

Other

OtherAmerican Society of Agricultural and Biological Engineers Annual International Meeting 2014, ASABE 2014
CountryCanada
CityMontreal
Period7/13/147/16/14

Keywords

  • Carbon source
  • Denitrification
  • Drainage
  • Nitrate
  • Water

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Mechanical Engineering

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  • Cite this

    Christianson, L. E., Hanly, J. A., & Hedley, M. J. (2014). Suitability of three wood species for denitrification bioreactor fill. In American Society of Agricultural and Biological Engineers Annual International Meeting 2014, ASABE 2014 (Vol. 2, pp. 1447-1457). American Society of Agricultural and Biological Engineers.