Estimation of flow and transport parameters for woodchip-based bioreactors: II. field-scale bioreactor

J. A. Chun, R. A. Cooke, J. W. Eheart, J. Cho

Research output: Contribution to journalArticlepeer-review


To reduce nitrate-N from tile drains, subsurface bioreactors using woodchips as a carbon source for denitrification have been installed for the past two decades. The objectives of this study were to estimate effective porosity, longitudinal and transverse dispersivity, and first- or zero-order decay coefficients for a field-scale bioreactor with woodchips as the carbon source. In a field-scale bioreactor (6.1 m by 6.1 m) installed at Decatur, IL nitrate-N concentrations were monitored in 16 monitoring wells installed at 1.5 m intervals and 0.75 m from each corner. An interpolation method was used for transient, two-dimensional groundwater flow, and the Random Walk Method which does not introduce numerical dispersion errors was used for two-dimensional nitrate-N transport. Nonlinear techniques for fitting the numerical solution to the observed breakthrough curves were used to estimate the transport parameters for the field-scale bioreactor. The longitudinal and transverse dispersivity, the first-order decay coefficient, and the effective porosity were estimated as 10.2 cm, 1.13 cm, 0.01 h-1, and 0.79, respectively. Under a pulse of nitrate-N, high reduction rate of nitrate-N in mass (approximately 47% for 269.9 g nitrate-N of the input mass) was observed at the outlet of the field-scale bioreactor at 4.4 h of hydraulic retention time. This result suggests that field-scale bioreactors using woodchips as a carbon source may be used to provide significant nutrient reduction from tile-drained fields.

Original languageEnglish (US)
Pages (from-to)95-102
Number of pages8
JournalBiosystems Engineering
Issue number1
StatePublished - Jan 2010

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Food Science
  • Animal Science and Zoology
  • Agronomy and Crop Science
  • Soil Science


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