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Browsing by Subject "bioreactor"

Now showing 1 - 6 of 6
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    Identification of Microorganisms for the Bioremediation of Nitrate and Manganese in Minnesota Water
    (2018-08) Anderson, Emily
    Bioremediation is a way to safely and cost-effectively remove contaminants using living organisms. In this thesis, microorganisms capable of remediating two pollutants, nitrate and manganese, were identified using culture-dependent and –independent approaches. Nitrate in agricultural wastewater can lead to algal blooms and eutrophication. Edge-of-field woodchip bioreactors are a promising approach to prevent nitrate in wastewater from reaching surface waters by utilizing microbial denitrification to remove nitrate from the system. However, woodchip bioreactors experience low efficiency under cold temperatures, so one strategy to enhance bioreactors in the early spring involves bioaugmentation, or inoculating the bioreactors with cold-adapted denitrifying microorganisms. In order to identify a cold-adapted denitrifier for bioaugmentation, microorganisms were isolated from field woodchip bioreactors and subjected to denitrification testing under cold temperatures, measuring nitrate, nitrite, ammonium, nitrous oxide and dinitrogen gas, as well as whole genome sequencing to identify the presence of genes involved in denitrification and other important microbial processes. Based off of these results, two strains, Microvirgula sp. BE2.4 and Cellulomonas sp. WB94 were recommended for bioaugmentation. In part two, manganese was addressed. High levels of manganese in drinking water can cause health problems, and common treatment methods require cost-intensive chemicals, conditions and maintenance. In this study, a novel algae bioreactor was established to remove manganese from water. In this bioreactor, the algae provided fixed carbon for manganese-oxidizing microorganisms that oxidized the dissolved manganese, precipitating it out of solution. Using a culture-dependent approach, manganese-oxidizing bacteria and fungi were isolated from an environmental sample, including known oxidizers Bosea, Pseudomonas, Plectosphaerella and Phoma and some not previously known to oxidize manganese such as Aeromonas, Skermanella, Ensifer and Aspergillus. A culture-independent approach was also employed to determine how abundant the isolated manganese-oxidizing bacteria are in an actively oxidizing environmental sample. Using nitrate and manganese as examples, this thesis identified useful microorganisms involved in remediation and demonstrated how microorganisms can be utilized to effectively remove pollutants from the environment.
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    Origin and development of fungal communities in an engineered biofilter
    (2017-05-09) Oliver, Jason; Song, Zewei; Schilling, Jonathan S; schillin@umn.edu; Schilling, Jonathan
    Microbial communities underpin the performance of biofilters used for treating pollutants, but community ‘seeding’ and development is not well understood, particularly for fungi. Fungi have unique biocatalytic potential in biofilters, and identifying their inoculum sources and community succession can inform design and management strategies to improve biofilter operation. Our goal was to track fungal community development in a full-scale woodchip biofilter treating air exhaust from a swine barn facility. We sequenced fungal ITS-1 amplicons 1) from potential inoculum sources (fresh wood chip media; manure from pits below pig housing) and 2) from wood chip biofilms at the inlet and outlet of the biofilter, sampling annually over 3 years. Inlet and outlet fungal communities were distinct at the outset, but became increasingly similar by year 3. A shift from Basidiomycetes and yeasts to Ascomycetes and molds was associated with a loss of richness as the community became dominated by fungi that originated from the manure exhaust. Notably, dominant taxa were pig skin dermatophytes, likely seeded continuously from within the barn. These patterns differ from those in natural wood decomposition studies, and the results suggest that hygiene within the barn will affect the performance of biofilters located outside of the barn, an aspect of biofilter management that has not been exploited. These ‘upstream’ inoculum effects may complicate management, however, our results identify several candidate fungi and an avenue for increasing inoculum potential on a continuous basis that might be valuable for seeding biofilters, improving control, and reduce lag-times during biofilter development.
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    Proceedings of the 4th Drainage Water Management Field Day
    (2011-08-23) Strock, Jeffrey S.; Gupta, Satish; Sands, Gary; Ranaivoson, Andry; Hay, Chris; Talbot, Mike; Magner, Joe
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    Proceedings of the 7th Soil and Water Management Field Day
    (2020) Strock, Jeffrey S; Dalzell, Brent; Garcia y Garcia, Axel; Pease, Lindsay; Fernandez, Fabian; Niaghi, Ali Rashid; Ranaivoson, Andry
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    Using unique carbon source combinations to increase nitrate and phosphate removal in bioreactors
    (2016-06) Roser, Marta
    Nitrogen (N) and phosphorus (P) losses from croplands contribute to impairment of water bodies. This study was conducted to test candidate denitrifying bioreactor media for nitrate-N and dissolved reactive P (DRP) removal from agricultural effluent in drainage ditches. The nitrate-N and DRP removal performance of carbon materials widely available in the Midwest, wood chips (WC) and corn cobs (CC), were compared to treatments of mixed materials: wood chips and hardwood biochar (WC+BC), wood chips and sodium acetate (WC+A), corn cobs and modified coconut coir (CC+MC), and corn cobs, modified coconut coir, and modified macadamia biochar (CC+MC+MBC). Water with a nitrate-N concentration of 20 mg N L-1 and a DRP concentration of 0.3 mg P L-1 was pumped through PVC columns packed with treatment media. The flow rate was adjusted to match the rise and decay of a typical drainage hydrograph. Effluent was sampled after hydraulic residence times (HRT) of 1.5, 8, 12, and 24 h. The laboratory experiment was conducted at 15°C for 14 weeks, 5°C for 13 weeks, and 15°C again for 7 weeks in a temperature controlled chamber, designated the warm run, cold run and rewarm run, respectively. Nitrate-N load reductions ranged from 24% to 96% in the warm and rewarm runs and from 4% to 80% in the cold run. Nitrate-N load reduction performance at all temperatures was in the order of: WC+A > CC+MC > CC > CC+MC+MBC > WC > WC+BC. The nitrate removal rate (NRR) was highest at the 1.5h HRT for the WC+A treatment at all temperatures. Cumulative DRP load reductions in the warm and rewarm runs were statistically higher in the CC, CC+MC, and CC+MC+MBC treatments, with DRP load reductions of 74%, 81%, and 67%, respectively. The WC+A treatment had the highest DRP load reduction in the cold run, with a 45% reduction. The CC, CC+MC, and CC+MC+MBC treatments had both high NRR and high DRP percent concentration removal in the warm and rewarm runs, but the WC+A treatment had higher removal of both nutrients in the cold run and specifically at lower HRTs. For both nitrate-N and DRP load reductions during high flows and cold temperatures, WC+A would be the recommended treatment. Future work should focus on the addition of carbon such as sodium acetate to enhance bioreactor performance during high drainage and cold temperature conditions.