Browsing by Subject "Filters"

Now showing 1 - 2 of 2
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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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    Investigating Wastewater Reuse at MnDOT Truck Stations
    (Minnesota Department of Transportation., 2019-05) Heger, Sara; Doro, Jessica; Rutter, Melissa C; Gustafson, Dave; Larson, Sondra
    The University of Minnesota (UMN) and the Minnesota Department of Transportation (MnDOT) conducted a study to determine whether implementing a wastewater reuse program would be a feasible option for MnDOT-owned truck washing stations. MnDOT has 137 truck stations in the state, where trucks are frequently washed to remove road salt build-up. MnDOT recognized an opportunity to potentially reuse the wastewater for appropriate greywater uses and recapture the salt for road use. Sampling was done to assess the wastewater contaminants in truck wash water at 11 truck-washing stations in Minnesota. Then technologies suited to removing organics and total suspended solids (TSS) but not chlorides were reviewed. The recommendation is that either a recirculating sand filter (RSF) or a membrane bioreactor (MBR) would be feasible technologies to use for this purpose. Using the MnDOT truck station in Arden Hills, Minnesota, an economic evaluation was done. Both systems could be used to effectively treat wastewater and produce brine for reuse, but the most economical solution for MnDOT would be to invest in a MBR. Compared with a RSF, an MBR is one-third less expensive over time, primarily due to low material and installation cost as well as a lower annual maintenance costs.