Theses and Dissertations at Montana State University (MSU)
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Item Effects of hydraulic loading on nitrification and denitrification processes in a two-stage, vertical flow treatment wetland at Bridger Bowl Ski Area(Montana State University - Bozeman, College of Engineering, 2020) Panighetti, Robert Arthur; Chairperson, Graduate Committee: Otto SteinA pilot-scale two-stage vertical flow treatment wetland (VFTW) at the Bridger Bowl Ski Area was used to evaluate the influence of hydraulic loading rate on COD removal, nitrification, and denitrification in the system. Hydraulic loading rates ranged between 36 cm/d to 60 cm/d over system years 2018 and 2019. Total nitrogen loading (sum of NH 4+ and NO 3-) ranged from 12 g/m 2d to 65 g/m 2d, and COD loading ranged from 58 g/m 2d to 172 g/m 2d. The system effectively removed COD in both years, with removals of 95% and 96% for influent COD concentrations of 555 mg/L and 607 mg/L, respectively. Influent total nitrogen was 141 mg/L in 2018 and 105 mg/L in 2019, and removals were 67% and 54%, respectively. At a hydraulic loading rate of 60 cm/d, COD removal declined in the first stage and ammonium removal declined in the second stage. At lower hydraulic loading rates (up to 48 cm/d), removal of COD, ammonium and nitrate increased in a consistent pattern with increased mass loading of the respective contaminant, suggesting a maximum hydraulic loading rate limit between 48 and 60 cm/d. The effect of hydraulic loading cannot be completely separated from mass loading of a contaminant, likely influenced by the level of partial saturation within the first stage and the recycle ratio; neither were varied in this study. A key limiting factor is hydraulic overload to the first stage, limiting removal of COD which interfered with nitrification in the second stage. A multivariate model for ammonium removal in the second stage predicts increased ammonium removal with increasing ammonium load but decreasing COD load. Despite operational performance variation the system met applicable discharge requirements, reinforcing the ability of a VFTW system to perform secondary wastewater treatment, even for high-strength wastewater and in cold climates.Item Effects of triclosan exposure on nitrification in activated sludge, biofilms, and pure cultures of nitrifying bacteria(Montana State University - Bozeman, College of Engineering, 2016) Bodle, Kylie Brigitta; Chairperson, Graduate Committee: Ellen LauchnorEmerging contaminants, such as pharmaceuticals or personal care products, have the potential to impact many wastewater treatment processes due to their antimicrobial properties. Nitrifying bacteria initiate the nitrogen removal process in wastewater treatment, and are particularly sensitive to inhibition by these and other contaminants. The impacts of the emerging contaminant triclosan (TCS) on two common nitrifying bacteria were evaluated under multiple growth conditions. The resilience of biofilms and suspended cell cultures of the ammonia oxidizing bacterium (AOB) Nitrosomonas europaea was compared during TCS exposure. Impacts of TCS on Nitrobacter winogradskyi, a common nitrite oxidizing bacterium (NOB), were also considered. Lastly, activated sludge biofilms and suspended cells were also exposed to TCS to further evaluate impacts on nitrification. Triclosan at part per million levels was found to reduce respiration in nitrifying biofilms, and NOB were much more impacted by TCS than AOB. Interestingly, biofilms of N. europaea were just as impacted by TCS as suspended cells. Triclosan adsorbed strongly to cellular material and degradation was only observed in activated sludge at low concentrations. Altogether, TCS was found to reduce nitrification by AOB and NOB, and the results suggest that its presence at high levels in wastewater treatment is likely to have negative consequences.Item Ammonia oxidation by a nitrifying community containing novel ammonia oxidizing archaea(Montana State University - Bozeman, College of Engineering, 2014) Olson, Andrew Jared; Chairperson, Graduate Committee: Anne CamperThe disinfection properties of chlorine have long been known. These properties have been leveraged in the disinfection of drinking water. However, in the presence of organic matter, chlorine can form potentially carcinogenic disinfection by-products (DBPs). As a result, the U.S. Environmental Protection Agency promulgated the Stage I and Stage II Disinfectants/Disinfection By-Products Rules, limiting the amount of DBPs that can be present in a distribution system. An economical solution for many drinking water utilities to meet these new regulations was to use to chloramine as a secondary disinfectant. However, chloramines are not without their own disadvantages: free ammonia is added during chloramine formation and released by chloramine decay. This free ammonia can then be used as an energy source by indigenous microoganisms during nitrification. Nitrification can have deleterious effects on drinking water such as decreased disinfectant residual, pH, dissolved oxygen, and alkalinity, as well as an increase in nitrite, nitrate, and heterotrophic bacteria. This study uses effluent from a nitrifying reactor simulating premise plumbing to quickly establish a nitrifying community in glass bead packed bed reactors. Importantly, ammonia oxidizing archaea have been identified in both systems while no known ammonia oxidizing bacteria have been found. Once this nitrifying community was established, the reactors were used as batch reactors with effluent recycle to measure ammonia oxidation during a two hour batch phase. A least squares regression analysis was performed to generate the kinetic constants v max and K m for the nitrifying community in the packed bed reactors. v max was calculated to be 2.23 hr -1. K m was calculated to be 2.35 mg L -1. This work will aid in the effort to characterize the nitrifying population in a premise plumbing system and mitigate nitrification in drinking water.Item Process optimization of an on-site wastewater treatment system for nitrogen removal(Montana State University - Bozeman, College of Engineering, 1997) Blicker, Brian RobertItem Nitrogen mineralization in selected Montana soils(Montana State University - Bozeman, College of Agriculture, 1985) Gavlak, Raymond GeorgeItem Use of vegetative filter strip for controlling nitrate and bacteria pollution from livestock confinement areas(Montana State University - Bozeman, College of Agriculture, 2000) Fajardo, Juan JoseItem Microbial ecology of nitrifying simulated premises plumbing(Montana State University - Bozeman, College of Letters & Science, 2012) Encarnacion, Gem Deangkinay; Chairperson, Graduate Committee: Anne Camper; Mark D. Burr and Anne K. Camper were co-authors of the article, 'Bacterial communities in nitrifying simulated premises plumbing' in the journal 'Water research' which is contained within this thesis.; Anne K. Camper was a co-author of the article, 'Detection and enrichment of a nitrifying community containing a novel archaeon from simulated premises plumbing' in the journal 'PLoS One' which is contained within this thesis.Because of the Stage 2 Disinfectants and Disinfection Rule limiting then concentration of disinfection by products in drinking water, the use of chloramine as an alternative to chlorine has been increasing. However, the ammonia introduced by chloramination can lead to nitrification which results in the production of nitrite and nitrate, leading to regulatory violations. Nitrification in reactors with copper and polyvinyl chloride (PVC) surfaces was established by indigenous organisms from Bozeman tap water and has been stably maintained for more than 6 years. Statistical analyses of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiles determined that the active bacterial populations were different in the two systems. The assemblage of the organisms was also different from the starting population (BAC influent) suggesting both material and ammonia/carbon source affect the population. No known ammonia oxidizing bacteria were detected suggesting the role of different group for ammonia oxidation. Fluorescence in situ hybridization (FISH) detected archaea in the biofilm from both reactors. Archaeal 16S rRNA gene sequences were found to be phylogenetically affiliated with known archaeal ammonia oxidizers. Two archaeal amoA sequences were amplified from the system as determined by DGGE. We propose to provisionally classify a detected archaeon as Candidatus Nitrosotenuis bozemanii, based on its affinity to Nitrosotenuis uzonensis (Hatzenpichler et al., in preparation). Bacterial abundances were comparable in the two systems but archaeal abundances were higher in the PVC reactor suggesting material effect on the overall microbial population composition and density. Enrichment in modified synthetic Crenarchaeota medium yielded a culture of archaea and bacteria that consistently oxidizes ammonia to nitrate. Attempts to isolate the archaeal component using antibiotics failed, suggesting the disruption of a possible beneficial relationship between the archaea and bacteria. Genes involved in the transformation of nitrogen within the system were also investigated and hao distantly related to that of ammonia oxidizing bacteria was detected but its potential role remains unknown. This study provides evidence of archaea associated with biofilms in drinking water and while further analysis is needed to definitively elucidate their role, results of this study prompts the reevaluation of the current concept of nitrification in drinking water.Item Nitrification in premise plumbing systems(Montana State University - Bozeman, College of Engineering, 2008) Rahman, Mohammad Shahedur; Chairperson, Graduate Committee: Anne CamperMonochloramine is increasingly used instead of free chlorine as a secondary disinfectant. Ammonia is introduced into water for monochloramine formation or by decay. Nitrification can have deleterious effects on water quality that may lead to regulatory violations. In this project water quality and influence of pipe material on the onset of nitrification and consequences of nitrification in premise plumbing were investigated. Also potential control strategies for nitrification were evaluated. Initially two types of copper coupons (new and old, i.e., pre-exposed to 0.1N NaOH solution) were used with water of two different carbon (2~4ppm) and ammonianitrogen (0.36~0.71ppm) concentrations. In the next experiment, pre-aged copper and PVC coupons were used with high carbon (4 ppm) and two ammonia concentrations (0.36 and 0.71 ppm). When all reactors showed complete signs of nitrification the ammonia concentration in low ammonia (0.36 ppm) feed reactors were raised to the high level (0.71 ppm). The PVC reactors were quicker in adjusting to this change. Next, the effect of copper ion, chlorite and chloramine on nitrifying simulated household plumbing systems was investigated. No significant effect of copper on nitrification was observed. Chlorite was not effective on the PVC system but inhibited the copper system at 20 ppm. Nitrification activity was also impacted significantly at a 5:1 ratio of chlorine to ammonia and ultimately stopped. To investigate the effect of nutrient conditions on metal release in a nitrifying system and the consequences of change in microbial population, influent humic and ammonia concentrations of two reactors of each set were raised to 8 ppm and 2.13 ppm respectively. Higher ammonia increased only the autotrophs while higher TOC increased only the heterotrophs. For all reactors alkalinity and pH decreased due to nitrification, with lesser effect on copper reactors. Increased TOC or nitrogen increased the copper concentration in the water. The microbial population was analyzed by PCR and DGGE. The biofilm community composition is influenced by nutrient condition and pipe material and environmental stress (chlorite or monochloramine). The presence of copper in the PVC reactor did not cause any impact on community composition.Item Analysis of microbial biofilm community composition within constructed wetlands(Montana State University - Bozeman, College of Letters & Science, 2010) Faulwetter, Jennifer Lynn; Chairperson, Graduate Committee: Anne Camper; Vincent Gagnon, Carina Sundberg, Florent Chazarenc, Mark D. Burr, Jacques Brisson, Anne K. Camper and Otto R. Stein were co-authors of the article, 'Microbial processes influencing performance of treatment wetlands: a review' in the journal 'Ecological engineering' which is contained within this thesis.; Mark D. Burr, Otto R. Stein and Anne K. Camper were co-authors of the article, 'Characterization of sulfate reducing bacteria in constructed wetlands' in the journal 'Proceedings of the 11th international conference on wetland systems for water pollution control, Indore, India' which is contained within this thesis.; Mark D. Burr, Albert E. Parker, Otto R. Stein and Anne K. Camper were co-authors of the article, 'The effect of plant species and sample location on bacterial biofilm communities associated with constructed wetland microcosms' in the journal 'The international society for microbial ecology journal' which is contained within this thesis.; Mark D. Burr, Albert E. Parker, Otto R. Stein and Anne K. Camper were co-authors of the article, 'The influence of sulfate reducing bacteria and ammonia oxidizing bacteria on nutrient cycling in constructed wetland microcosms' in the journal 'Microbial ecology' which is contained within this thesis.; Mark D. Burr, Alfred B. Cunningham, Frank M. Stewart, Anne K. Camper and Otto R. Stein were co-authors of the article, 'Floating treatment wetlands for domestic wastewater treatment' in the journal 'Water science and technology' which is contained within this thesis.Constructed wetlands (CWs) are ecologically-based water treatment systems that provide cost-effective amelioration of waterborne pollutants. Fundamental understanding of removal mechanisms, especially microbial processes, limits greater usage of constructed wetlands as a wastewater treatment system. The influence of plant species selection, season, and organic load rate on pollutant removal was previously linked to the redox condition of the sub-surface wetland environment. The goal of this research was to determine which of these environmental variables (including spatial location within the CW) influenced the dominant microbial populations and/or the activity of various sub-populations. Once identified, a constructed wetland might be optimized for growth of microorganisms involved in removal of a specific pollutant. To assess environmental factors, microbial population samples were taken in six locations (effluent, 3 root and 2 gravel areas) within replicate unplanted microcosms and wetland microcosms planted with Deschampsia cespitosa or Leymus cinereus during the summer (24°C) and winter (4°C) seasons. Microcosms were fed a synthetic domestic wastewater in 20-day batches for at least 12 months prior to sampling. The most recent techniques in molecular biology including denaturing gradient gel electrophoresis (DGGE) and quantitative PCR were utilized and included treatment with and without propidium monoazide (PMA) to distinguish between "live" and "dead" microbial communities. Primer sets targeted the entire bacterial community (16S rDNA) and two functional groups, nitrifying bacteria (amoA gene) and sulfate reducing bacteria (dsrB gene). Results indicated that overall microbial community structure (16S rDNA) was affected by general location within the microcosm (effluent, root, gravel) as well the plant species present. Specific microbial groups appeared to be affected differently with relative gene quantities of sulfate reducing bacteria and nitrifying bacteria being influenced by a combined effect of plant species and season. For dsrB, D. cespitosa had the lowest relative gene quantities overall. Both genes were more abundant in the summer season, indicating seasonal importance. Location within the microcosms was also important, with anoxic environments (column bottom) being more important for dsrB presence and a diverse population of cultivated sulfate reducers. The roots were an important location for both microbial diversity and activity for all genes investigated.