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Rivas A, Barkle G, Sarris T, Park J, Kenny A, Maxwell B, Stenger R, Moorhead B, Schipper L, Clague J. Improving accuracy of quantifying nitrate removal performance and enhancing understanding of processes in woodchip bioreactors using high-frequency data. Sci Total Environ 2023; 880:163289. [PMID: 37023810 DOI: 10.1016/j.scitotenv.2023.163289] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 03/15/2023] [Accepted: 03/31/2023] [Indexed: 05/27/2023]
Abstract
Woodchip bioreactors have gained popularity in many countries as a conservation practice for reducing nitrate load to freshwater. However, current methods for assessing their performance may be inadequate when nitrate removal rates (RR) are determined from low-frequency (e.g., weekly) concurrent sampling at the inlet and outlet. We hypothesised that high-frequency monitoring data at multiple locations can help improve the accuracy of quantifying nitrate removal performance, enhance the understanding of processes occurring within a bioreactor, and therefore improve the design practice for bioreactors. Accordingly, the objectives of this study were to compare RRs calculated using high- and low-frequency sampling and assess the spatiotemporal variability of the nitrate removal within a bioreactor to unravel the processes occurring within a bioreactor. For two drainage seasons, we monitored nitrate concentrations at 21 locations on an hourly or two-hourly basis within a pilot-scale woodchip bioreactor in Tatuanui, New Zealand. A novel method was developed to account for the variable lag time between entry and exit of a parcel of sampled drainage water. Our results showed that this method not only enabled lag time to be accounted for but also helped quantify volumetric inefficiencies (e.g., dead zone) within the bioreactor. The average RR calculated using this method was significantly higher than the average RR calculated using conventional low-frequency methods. The average RRs of each of the quarter sections within the bioreactor were found to be different. 1-D transport modelling confirmed the effect of nitrate loading on the removal process as nitrate reduction followed Michaelis-Menten (MM) kinetics. These results demonstrate that high-frequency temporal and spatial monitoring of nitrate concentrations in the field allows improved description of bioreactor performance and better understanding of processes occurring within woodchip bioreactors. Thus, insights gained from this study can be used to optimise the design of future field bioreactors.
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Affiliation(s)
- A Rivas
- Lincoln Agritech Ltd., Private Bag 3062, Hamilton 3240, New Zealand.
| | - G Barkle
- Land and Water Research Ltd., PO Box 27046, Garnett Ave., Hamilton 3257, New Zealand
| | - T Sarris
- Institute of Environmental Science and Research, PO Box 29-181, Christchurch 8540, New Zealand
| | - J Park
- Lincoln Agritech Ltd., Private Bag 3062, Hamilton 3240, New Zealand
| | - A Kenny
- Institute of Environmental Science and Research, PO Box 29-181, Christchurch 8540, New Zealand
| | - B Maxwell
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801-4730, USA
| | - R Stenger
- Lincoln Agritech Ltd., Private Bag 3062, Hamilton 3240, New Zealand
| | - B Moorhead
- Lincoln Agritech Ltd., Private Bag 3062, Hamilton 3240, New Zealand
| | - L Schipper
- University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - J Clague
- Lincoln Agritech Ltd., Private Bag 3062, Hamilton 3240, New Zealand
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Anderson BJ, Decker RB, Paschalidis NP, Sarris T. Onset of nonadiabatic particle motion in the near-Earth magnetotail. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97ja00798] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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