Denitrifying bioreactor response during storm events

William T. Pluer, Chelsea K. Morris, M. Todd Walter and Larry D. Geohring

Agricultural Water Management, 2019, vol. 213, issue C, 1109-1115

Abstract: Denitrifying bioreactors can be an effective management strategy to address excess nitrate from tile-drained fields. However, there has been minimal research on how bioreactors function during storm events, which can account for large portions of annual nitrate load. Storm events cause reduced hydraulic retention time and potentially temperature and flow path fluctuations that may disturb denitrifying microbial communities within the bioreactor. In this study, nitrate concentration and flow rate were monitored during baseflow and storm-induced flow in four denitrifying bioreactors treating agricultural tile drainage to compare removal rate (RR) and removal efficiency (RE) between flow conditions. Removal rate was higher in stormflow than baseflow for all the bioreactors, though this was only significant for two bioreactors. However, RR was lower on average following events compared with pre-storm rates. Lag time, the period between a parcel of water entering the bioreactor and exiting, ranged between 2 and 24 h for the observed storms. Calculations of RR and RE that account for lag time were significantly lower than standard calculations. The model of RR that included a variable of flow variation (coefficient of variation in flow over a 24-hour period) was most effective at describing observed data. This, along with differences in RR between baseflow and stormflow, suggests that bioreactor function in storms should be considered separately from baseflow. Decreased RR following storms also suggests that bioreactors may require additional design considerations to reduce disturbance, especially for fields where much of the annual nitrate runoff load is concentrated in storm-induced events.

Keywords: Denitrifying bioreactor; Stormwater; Drainage; Hydraulic retention time (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378377418311090
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:213:y:2019:i:c:p:1109-1115

DOI: 10.1016/j.agwat.2018.12.004

Access Statistics for this article

Agricultural Water Management is currently edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Bibliographic data for series maintained by Catherine Liu ().