Agricultural and Biosystems Engineering Publications

Campus Units

Agricultural and Biosystems Engineering

Document Type

Article

Publication Version

Published Version

Publication Date

11-12-2015

Journal or Book Title

Journal of Environmental Quality

DOI

10.2134/jeq2015.03.0161

Abstract

Woodchip denitrification bioreactors, a relatively new technology for edge-of-field treatment of subsurface agricultural drainage water, have shown potential for nitrate removal. However, few studies have evaluated the performance of these reactors under varied controlled conditions including initial woodchip age and a range of hydraulic retention times (HRTs) and temperatures similar to the field. This study investigated (i) the release of total organic C (TOC) during reactor start up for fresh and weathered woodchips, (ii) nitrate (NO3–N) removal at HRTs ranging from 2 to 24 h, (iii) nitrate removal at influent NO3–N concentrations of 10, 30, and 50 mg L−1, and (iv) NO3–N removal at 10, 15, and 20°C. Greater TOC was released during bioreactor operation with fresh woodchips, whereas organic C release was low when the columns were packed with naturally weathered woodchips. Nitrate-N concentration reductions increased from 8 to 55% as HRT increased. Nitrate removal on a mass basis (g NO3–N m−3 d−1) did not follow the same trend, with relatively consistent mass removal measured as HRT increased from 1.7 to 21.2 h. Comparison of mean NO3–N load reduction for various influent NO3–N concentrations showed lower reduction at an influent concentration of 10 mg L−1 and higher NO3–N reductions at influent concentrations of 30 and 50 mg L−1. Nitrate-N removal showed a stepped increase with temperature. Temperature coefficient (Q 10) factors calculated from NO3–N removal rates ranged from 2.2 to 2.9.

Comments

This article is from Journal of Environmental Quality (2015), doi:10.2134/jeq2015.03.0161.

Access

Open

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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