Browsing by Subject "Peat"

Now showing 1 - 5 of 5
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    Continued Monitoring of Stormwater Effluents from Filter Media in Two Bioslope Sites
    (Minnesota Department of Transportation, 2021-06) Cai, Meijun; Patelke, Marsha; Saftner, David
    Over the last thirty years, the Minnesota Department of Transportation (MnDOT) has implemented biofilters along roadways as a stormwater control measure. The state and national regulations require that the biofilters must be able to infiltrate and treat the first inch of rainfall onsite. However, the performance of the biofilters after installation has rarely been studied. An early phase of this project monitored two newly constructed biofilter sites for two years and for three months, respectively. This study extended the monitoring of soil moisture changes and infiltration water quality for another two years (2019-2020). Over the four-year monitoring period, both salvage peat and compost materials showed the capacity to retain the first inch of runoff, and this retention capacity did not change over the study period. The drainage water quality showed significantly temporal trends, particularly phosphorus concentrations, which were declining significantly for both compost and salvage peat. The application of tailing with compost can reduce the phosphorus release. The leachate from salvage peat has similar metal concentrations but much lower phosphorus concentrations (below 100 ppb) than the compost. The lowest chemical concentrations were achieved when the soil mixture contained 10% compost and 10% salvage peat, implying the best stormwater control practice is to limit the organic ratio to around 20%. Findings from this work determined the validity of using peat and compost for future biofilters and can aid in future design.
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    Development and Regionalization of In Situ Bioslopes and Bioswales
    (Minnesota Department of Transportation, 2019-07) Johnson, Kurt W.; Cai, Meijun; Patelke, Marsha; Saftner, David; Cruz, Chanelle
    This project is a multi-disciplinary investigation into the use of alternative media for biofiltration systems in Minnesota. Over the last thirty years, the Minnesota Department of Transportation (MnDOT) has implemented biofilters along roadways as a stormwater control measure. These systems must be able to infiltrate and treat the first inch of rainfall onsite to meet state and national regulations. The performance of a biofilter is largely based on its media?s ability to infiltrate water, sustain vegetation, and capture pollutants. To date, MnDOT has relied on sand and compost mixtures for biofilter media components. An early phase of this work identified peat as having similar performance characteristics as compost, making it an ideal alternative. A laboratory testing program was also developed during the early phase of work to determine media properties that could be used to predict biofilter performance. This project focused on characterizing existing biofilters using in situ testing and comparing results to laboratory testing. The comparison of the two methods demonstrated the predictive capabilities of the laboratory regime. This project also included the instrumentation and monitoring of field sites including a newly constructed peat amended biofilter. Findings from this work determined the validity of using peat for future biofilters and can aid in identifying and characterizing other alternative media.
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    Development of Granulated Sorbents: Semi-Annual Progress Report
    (University of Minnesota Duluth, 1995-02) Hagen, Timothy S
    A semi-annual progress and financial report on developing and commercializing an effective absorbent peat granule for use in removing metals and hydrocarbons from wastewaters.
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    The Effect Of Climate Change On Mercury In Boreal Peatlands
    (2023-09) Pierce, Caroline
    Mercury is a ubiquitous pollutant that accumulates in peatlands, an ecosystem highly sensitive to climate change. Methylmercury (MeHg) is a neurotoxin that is capable of biomagnifying in food webs. We examined the effects of increasing temperature and elevated atmospheric carbon dioxide (CO2) on the concentration of total mercury (THg) and MeHg in peatland soil. This research was performed at the Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment, an ecosystem-scale manipulation in an ombrotrophic bog in northern Minnesota, USA, which includes five temperature levels (ambient plus above- and below-ground warming), with ambient or enhanced CO2 concentration. Increased temperature led to decreased MeHg concentrations in peat and increased THg and MeHg in porewaters. This decrease in peat MeHg, and increases in THg and MeHg in porewater could be caused by more rapid decomposition of the peat leading to mercury mobilization, increased methylation/demethylation rates, or increased gaseous mercury emission. The response to elevated atmospheric CO2 was limited to the surface depths of peat. Total mercury and MeHg decreased in the peat and increased in the porewater. There are no known direct effects of CO2 on mercury cycling so this finding is likely due to changes in other response variables such as the lowering of the water table or changes in the proportion of different plant species. Overall, we observed that temperature and CO2 had significant but subtle effects on THg and MeHg retention in peat. Our findings indicate that mercury concentrations in peat may decrease with climate change which may shift the system from a mercury sink to a mercury source.
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    NRRI Peat Collection: Evaluating a Working Research Collection
    (2016-06-14) Enrici, Pam; Grebinoski, Jodi Carlson