Denitrifying bioreactor woodchip sourcing guidance based on physical and hydraulic properties

Johnson, Gabriel M.; Christianson, Reid; Cooke, Richard A.; Díaz-García, Carolina; Christianson, Laura E.

doi:10.1016/j.ecoleng.2022.106791

Cited by 6 publications

(9 citation statements)

References 23 publications

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“…For each test across the moisture content gradient, the permeameter was packed in five layers, and each layer was tamped ten times. This compaction was selected to simulate an expected maximum for the three woodchip types (Johnson et al, 2022) to allow a consistent comparison for the moisture content/bulk density evaluation.…”

Section: Bulk and Particle Densitymentioning

confidence: 99%

“…Permeability coefficient testing and drainable porosity measured in the permeameters (20 cm diameter; 77 cm total column height) followed standard methods and were illustrated by Johnson et al (2022) (ASTM, 2019). In the previous study, permeability coefficient was referred to as saturated hydraulic conductivity, and the same method is used here for consistency in comparing results, although the new term (permeability coefficient) is used.…”

Section: Permeability Coefficient and Drainable Porositymentioning

confidence: 99%

“…Current knowledge of woodchip bulk density for bioreactor applications stems from laboratory permeameter studies, which often report around 200 ± 25 kg/m 3 dry bulk density (Ghane et al, 2014;Feyereisen and Christianson, 2015;Johnson et al, 2022). A variety of packing procedures, such as shaking the permeameter, tamping, or not tamping, have W been used to simulate field compaction in the lab, although it is unknown how well these procedures mimic in situ conditions (Feyereisen and Christianson, 2015;Ghane et al, 2016;Cameron and Schipper, 2010).…”

mentioning

confidence: 99%

“…A variety of packing procedures, such as shaking the permeameter, tamping, or not tamping, have W been used to simulate field compaction in the lab, although it is unknown how well these procedures mimic in situ conditions (Feyereisen and Christianson, 2015;Ghane et al, 2016;Cameron and Schipper, 2010). Johnson et al (2022) recently documented that most woodchip types reach maximum compacted dry bulk density at 120% to 145% of their uncompacted dry bulk density. It would be useful to know (1) if woodchip bulk densities in operational bioreactors differ from those previously measured in the lab, and, if so, (2) if those differences are sufficient to impact bioreactor design model input parameters like drainable porosity.…”

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confidence: 99%

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Denitrifying Bioreactor In Situ Woodchip Bulk Density

Christianson¹,

Christianson²,

Díaz-García³

et al. 2023

Journal of the ASABE

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Highlights The bulk density of woodchips in denitrifying bioreactors in the field is unknown. In situ bulk density estimation methods were developed for use during construction or excavation. Dry bulk densities of aged woodchips at bioreactor bottoms were lower than previous literature values. Moisture and particle size and density explained some, but not all, of the variation in in situ bulk densities. Abstract. Woodchip bulk density in a denitrifying bioreactor governs system hydraulics, but this prime physical attribute has never been estimated in situ. The objectives were twofold: (1) to establish estimates of in situ woodchip bulk density at bioreactors in the field, and (2) evaluate causal factors for and resulting impacts of these estimates. Proof-of-concept bulk density methods were developed at a pilot-scale bioreactor using three ways to estimate volume: surveying the excavated area, pumping the excavation full through a flow meter, and using iPhone Light Detection and Ranging (LiDAR). These methods were then further tested at two new and three old full-size bioreactors. Additional ex situ (off-site) testing with the associated woodchips included analysis of bulk density along a moisture gradient and particle size, particle density, wood composition, and hydraulic property testing. In situ dry bulk densities based on the entire volume of the new bioreactors (206-224 kg/m3) were similar to values from previous lab-scale studies. In situ estimates for woodchips at the bottom of aged bioreactors (22-mo. to 6-y) were unexpectedly low (120-166 kg/m3), given that these woodchips would presumably be the most compacted. These low moisture-content corrected dry bulk densities were influenced by high moisture contents in situ (>70% wet basis). The impacts of particle size and particle density on bulk density were somewhat mixed across the dataset, but in general, smaller woodchips had higher dry bulk densities than larger, and several woodchips sourced from the bottom of bioreactors had low particle densities. Although dry bulk densities in the zone of flow in bioreactors in the field were shown to be relatively low, the resulting permeability coefficients under those packing conditions did not differ from those of the original woodchips. The LiDAR-based volume estimation method was the most practical for large-scale, full-size evaluations and allowed high precision with small features (e.g., vertical reactor edges, drainage fittings). Keywords: Compaction, Cone penetrometer, Drainable porosity, LiDAR, Moisture content, Survey.

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Section: Bulk and Particle Densitymentioning

confidence: 99%

Section: Permeability Coefficient and Drainable Porositymentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Denitrifying Bioreactor In Situ Woodchip Bulk Density

Christianson¹,

Christianson²,

Díaz-García³

et al. 2023

Journal of the ASABE

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“…The CS and the WC used were locally sourced and selected properties are shown in Table 1. Detailed properties of the WC used are reported in Johnson et al (2022). Each bioreactor compartment was filled with one of the three different media/substrates (treatments): WC, CS, and CS-WC (1:1 v/v mixture of CS and WC), randomly assigned.…”

Section: Field Layout Preparation Tiling and Bioreactor Installationmentioning

confidence: 99%

Effectiveness of denitrification bioreactors with woodchips, corn stover, and phosphate‐sorbing media for simultaneous removal of drainage water N and P in a corn–soybean system

et al. 2023

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Millions of acres of farmland in the midwestern United States (US) are artificially drained, and this contributes to the export of nitrogen (N) and phosphorus (P) from agricultural land to surface water. Using a 36-acre tile-drained farm field, effects of P-sorbing media in combination with a denitrifying bioreactor system constructed with woodchips (WC) and corn stover (CS) on reducing nutrient export in drainage water were tested for 3 cropping years (2018-2020). The field was divided into three subfields as replicates. In each subfield, the drainage water was divided and separately channeled into three bioreactors, each of which contains one of the three different substrates: WC, CS, and CS-WC (1:1 v/v mixture of CS and WC), randomly assigned. The outlet of each compartment contained a 2.25 L flow-through chamber filled with activated iron (Fe) filings as P-sorbing material. Both WC and CS bioreactors were effective in removing drainage NO 3 − with a 77% (WC), 86%(CS), and 89% (CS-WC) reduction in mean NO 3 − -N concentration. For the three cropping years, the WC bioreactor reduced the total drainage inorganic N (NO 3 − -N + NH 4 + -N) load by 72%, but the CS bioreactor increased the total inorganic N load in the drainage water due to the substantial release of NH 4 + with the decomposition of CS. The breakdown of CS also increased drainage P. The NH 4 + and P release decreased with the decrease in the proportion of CS; thus, not more than 10% of CS is recommended for blending with WC to enhance the performance of a bioreactor.The P-sorbing Fe filing media reduced the P loads in drainage by an average of 19% during the 2-year study.

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