Mitigation of sulfate reduction and nitrous oxide emission in denitrifying environments with amorphous iron oxide and biochar

Easton, Zachary M.; Rogers, Mark; Davis, M.L.; Wade, James; Eick, Mathew; Bock, Emily

doi:10.1016/j.ecoleng.2015.05.008

Cited by 35 publications

(14 citation statements)

References 36 publications

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“…This was 41 and 54% of inflow NO x through two growing seasons. The removal rate in the biochar reactor was significantly greater than the woodchip reactor, similar to findings in the laboratory experiment and by Easton et al (2015). Although sample concentrations varied over time (coefficients of variation in outflow concentrations each ranged from 0.7 to 1.4), removal rate was significantly greater than zero ( p < 0.001) for each reactor.…”

Section: Resultssupporting

confidence: 81%

“…Effective treatment of P uses different processes from those associated with N removal because of its contrasting properties; removal of P typically focuses on sorption rather than biological processes, which are effective for N removal (Sharpley et al, 1994). A few studies on reactors have attempted a common strategy, specifically combining diverse media that facilitate treatment of N and P (Schipper et al, 2010b; Anderson et al, 2011; Easton et al, 2015). Biochar is a soil additive created from the pyrolysis of organic matter that has a high affinity for sorbing organic matter, nutrients, and metals (Lehmann et al, 2006).…”

mentioning

confidence: 99%

“…Phosphate readily sorbs to biochar (Anderson et al, 2011; Angst et al, 2013; Bock et al, 2015). Although some initial work has examined biochar‐amended woodchip reactors (Bock et al, 2015; Easton et al, 2015), potential for biochar as a media augmentation to retain P warrants investigation in field‐scale, flow‐through reactors.…”

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confidence: 99%

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Controls Influencing the Treatment of Excess Agricultural Nitrate with Denitrifying Bioreactors

et al. 2016

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Denitrifying bioreactors have been suggested as effective best management practices to reduce nitrate and nitrite (NO x ) in largescale agricultural tile drainage. This study combines experiments in flow-through laboratory reactors with in situ continuous monitoring and experiments in a pair of field reactors to determine the effectiveness of reactors for small-scale agriculture in New York. It also compares the use of a typical woodchip media with a woodchip and biochar mixture. Laboratory results showed linear increase in NO x removal with both increased inflow concentration and increased residence time. Average removal of NO x in weekly monitoring of field reactors over the course of two growing seasons was 3.23 and 4.00 g N m -3 d -1 for woodchip and woodchip/biochar reactors, respectively. Removal of NO x during two field experimental runs was similar to in situ monitoring and did not correlate with laboratory experiments. Factors that are uncontrollable at the field scale, such as temperature and inflow water chemistry, may result in more complex and resilient microbial communities that are less specialized for denitrification. Further study of other controlling variables, other field sites, and other parameters, including microbial communities and trace gas emissions, will help elucidate function and applicability of denitrifying bioreactors. Controls Influencing the Treatment of Excess Agricultural Nitrate with Denitrifying BioreactorsWilliam T. Pluer,* Larry D. Geohring, Tammo S. Steenhuis, and M. Todd Walter N onpoint-source nutrient pollution from agriculture remains a significant issue despite continued efforts to mitigate it. Nitrogen (N) and phosphorus (P) pollution leads to lowered water quality in freshwater and coastal regions, degrading biological, ecological, social, and economic value of the environment (Galloway et al., 2004). Excess N, most commonly found as nitrate (NO 3 -) in water, is a problem for estuarine and marine systems in particular (Shirmohammadi et al., 1995;Kemp et al., 2005). Biological assimilation and denitrification are the two primary mechanisms for removing NO 3 -. Denitrification is the reduction of NO 3 -along the following pathway (Groffman et al., 2006):Engineered solutions using denitrification to mitigate N pollution, including wetlands and riparian buffers, are intended to completely reduce NO 3 -and NO 2 -(NO x ) to N 2 (Burgin et al., 2013;Groh et al., 2015). Ideally, by bringing this process to completion, the release of intermediate products is avoided. All of these products have the potential for negative environmental impacts, including ozone depletion, greenhouse effect, and nitrite poisoning (Seitzinger et al., 2006).One solution under investigation is the denitrifying bioreactor, which intercepts runoff, tile drainage, and/or shallow groundwater from agricultural fields for treatment before water discharges to a receiving water body (Schipper et al., 2010b). Reactors are designed to provide ideal conditions for denitrification: an anaerobic enviro...

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Section: Resultssupporting

confidence: 81%

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confidence: 99%

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Controls Influencing the Treatment of Excess Agricultural Nitrate with Denitrifying Bioreactors

et al. 2016

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“…The effect of biochar on microbial sulfate reduction process has been little investigated so far. The barely researches reported that biochar amendment did not increase the sorption capacity of soil for SO 4 2- ( Zhao et al, 2017 ) and it could enhance the SO 4 2- reduction (to sulfide) by 85% compared to the initial concentration ( Easton et al, 2015 ), but the mechanisms involved had not been well discussed. In our study, biochar amendment also significantly increased the microbiological reduction of SO 4 2- , which is highly consistent with increased abundance of sulfate reducer ( Desulfobulbaceae and Desulfobacteraceae ) with biochar amendment ( Figure 3C ).…”

Section: Discussionmentioning

confidence: 99%

Typical Soil Redox Processes in Pentachlorophenol Polluted Soil Following Biochar Addition

et al. 2018

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Reductive dechlorination is the primary pathway for environmental removal of pentachlorophenol (PCP) in soil under anaerobic condition. This process has been verified to be coupled with other soil redox processes of typical biogenic elements such as carbon, iron and sulfur. Meanwhile, biochar has received increasing interest in its potential for remediation of contaminated soil, with the effect seldom investigated under anaerobic environment. In this study, a 120-day anaerobic incubation experiment was conducted to investigate the effects of biochar on soil redox processes and thereby the reductive dechlorination of PCP under anaerobic condition. Biochar addition (1%, w/w) enhanced the dissimilatory iron reduction and sulfate reduction while simultaneously decreased the PCP reduction significantly. Instead, the production of methane was not affected by biochar. Interestingly, however, PCP reduction was promoted by biochar when microbial sulfate reduction was suppressed by addition of typical inhibitor molybdate. Together with Illumina sequencing data regarding analysis of soil bacteria and archaea responses, our results suggest that under anaerobic condition, the main competition mechanisms of these typical soil redox processes on the reductive dechlorination of PCP may be different in the presence of biochar. In particularly, the effect of biochar on sulfate reduction process is mainly through promoting the growth of sulfate reducer (Desulfobulbaceae and Desulfobacteraceae) but not as an electron shuttle. With the supplementary addition of molybdate, biochar application is suggested as an improved strategy for a better remediation results by coordinating the interaction between dechlorination and its coupled soil redox processes, with minimum production of toxic sulfur reducing substances and relatively small emission of greenhouse gas (CH4) while maximum removal of PCP.

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“…Large volumes of solid-phase reactive materials are required in treatment systems to control the release of metals and other contaminants to the environment. For example, construction of permeable reactive barriers [1,2], containerized treatment systems [3,4], and alternative treatment wetlands [5][6][7] all require use of large volumes of adsorbents, reductants, or other treatment materials.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of mercury removal by biochars produced from different feedstocks determined using X-ray absorption spectroscopy

Liu

Ptacek

Blowes

et al. 2016

Journal of Hazardous Materials

124

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Thirty-six biochars produced from distinct feedstocks at different temperatures were evaluated for their potential to remove mercury (Hg) from aqueous solution at environmentally relevant concentrations. Concentrations of total Hg (THg) decreased by >90% in batch systems containing biochars produced at 600 and 700 °C and by 40-90% for biochars produced at 300 °C. Elevated concentrations of SO4(2-) (up to 1000 mg L(-1)) were observed in solutions mixed with manure-based biochars. Sulfur X-ray absorption near edge structure (XANES) analyses indicate the presence of both reduced and oxidized S species in both unwashed and washed biochars. Sulfur XANES spectra obtained from biochars with adsorbed Hg were similar to those of washed biochars. Micro-X-ray fluorescence mapping results indicate that Hg was heterogeneously distributed across biochar particles. Extended X-ray absorption fine structure modeling indicates Hg was bound to S in biochars with high S content and to O and Cl in biochars with low S content. The predominant mechanisms of Hg removal are likely the formation of chemical bonds between Hg and various functional groups on the biochar. This investigation provides information on the effectiveness and mechanisms of Hg removal that is critical for evaluating biochar applications for stabilization of Hg in surface water, groundwater, soils, and sediments.

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Mitigation of sulfate reduction and nitrous oxide emission in denitrifying environments with amorphous iron oxide and biochar

Cited by 35 publications

References 36 publications

Controls Influencing the Treatment of Excess Agricultural Nitrate with Denitrifying Bioreactors

Controls Influencing the Treatment of Excess Agricultural Nitrate with Denitrifying Bioreactors

Typical Soil Redox Processes in Pentachlorophenol Polluted Soil Following Biochar Addition

Mechanisms of mercury removal by biochars produced from different feedstocks determined using X-ray absorption spectroscopy

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