Theses and Dissertations at Montana State University (MSU)
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Item Assessing a novel approach to pharmaceutical removal from wastewater: aerobic granular sludge(Montana State University - Bozeman, College of Engineering, 2024) Bodle, Kylie Brigitta; Chairperson, Graduate Committee: Catherine Kirkland; This is a manuscript style paper that includes co-authored chapters.Pharmaceutical concentrations in various environmental matrices are increasing across the globe. Effluent discharge from wastewater treatment plants is a major vector by which pharmaceuticals enter the environment, as many of these compounds are not biodegradable under conventional wastewater treatment conditions. Although concentrations are currently low (ng/L to ?g/L levels), pharmaceutical contamination poses risks to both human and animal health, as many pharmaceuticals can have toxic effects on fish, birds, and small mammals, as well as contribute to the proliferation of antibiotic resistance genes in bacteria. Aerobic granular sludge (AGS), an emerging biofilm-based wastewater treatment biotechnology and the subject of this dissertation, may be capable of enhancing pharmaceutical removal from wastewater. Scientific literature indicates that AGS uses a mixture of both biodegradation and adsorption to remove pharmaceuticals, but thus far, studies on this topic are limited. The research detailed herein investigated how AGS was affected by a mixture of three common, but relatively unstudied, pharmaceuticals: diclofenac (anti-inflammatory), erythromycin (antibiotic), and gemfibrozil (lipid regulator). Studies described herein examined how AGS grown in two different environments--the lab versus a full-scale wastewater treatment plant--responded to pharmaceuticals. Pharmaceutical effects on wastewater treatment efficacy, active microbial populations, and biofilm structures were investigated. Pharmaceutical fates in both the aqueous and solid phases were also tracked. In general, lab-grown AGS was more negatively impacted by pharmaceutical exposure, evidenced by reduced wastewater treatment efficacy, declines in key wastewater-treating microbial populations, and reductions in biofilm lipid content. Pharmaceuticals were also poorly removed by lab-grown granules. In contrast, key microbial populations and biofilm structures remained stable throughout dosing in environmentally-grown AGS, and gemfibrozil was completely biodegraded. An important caveat to comparison of the two studies, however, is that the pharmaceutical dose to lab-grown AGS was approximately double that to environmental granules. Altogether, the research described herein demonstrates the promise of AGS as a dual wastewater and pharmaceutical treatment technology, but illustrates the importance of conducting experiments under conditions as environmentally relevant as possible.Item Influence of dose volume on nitrogen removal in a two stage vertical flow treatment wetland: Bridger Bowl ski area case study(Montana State University - Bozeman, College of Engineering, 2023) Brush, Kristen Onofria; Chairperson, Graduate Committee: Otto SteinTreating wastewater in remote locations does not require compromising the effluent quality discharged to the environment. A two-stage vertical flow treatment wetland (VF TW) with recycle meets this objective by removing high inputs of chemical oxygen demand (COD) and nitrogen (N) while requiring minimal maintenance and operator oversight. A 95.2 m 2 pilot scale VF TW at Bridger Bowl Ski Area, near Bozeman, MT, effectively treats the high strength domestic wastewater produced onsite. The partially saturated first stage of the VF TW removes influent COD and an unsaturated second stage nitrifies influent ammonium. Recycling second stage effluent to the first stage allows for nitrate removal by denitrification in the saturated zone of the first stage. Previous research indicated the system experiences near complete nitrification in the second stage and that total nitrogen removal is limited by denitrification in the first stage, potentially due to low organic carbon (COD) availability in the saturated zone. Therefore, the goal of the current study was to increase the COD:N ratio of the water entering the first-stage saturated zone by increasing the dose depth of influent (septic) water, high in COD, thereby reducing COD removal in the unsaturated layer. To evaluate denitrification performance a simplified stoichiometric process model accounted for both nitrate created and COD removed in the first stage unsaturated zone. During the 21-22 season, approximately 7 cm/day of septic water was applied to the first stage in either 1.2 or 2.5 cm doses. The larger doses showed enhanced nitrate removal efficiency in the saturated zone; however, a changing influent water quality may have supplemented efficiency improvement. During the 22-23 season, 12 cm/day of septic water was applied to the first stage in either 1 or 4 cm doses. During this experiment, influent water quality was the same, and the larger dose depths did not show enhanced nitrate removal. However, decreasing the septic dose depth increased first stage nitrification from 20 to 48% and COD removal from 77 to 82%. Throughout both experiments, system COD removal was > 95% (influent COD > 750 mg/L) and system ammonia removal was > 98% (influent NH 4 >160 mg/L).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 Influence of saturation on denitrification in a two-stage, vertical flow treatment wetland at Bridger Bowl ski area(Montana State University - Bozeman, College of Engineering, 2018) Woodhouse, Shayla Lee; Chairperson, Graduate Committee: Otto SteinA full-scale two-stage vertical flow treatment wetland (VF TW) pilot system was installed at the Bridger Bowl Ski Area in 2013 to test its capability as a secondary wastewater treatment system. Water quality was monitored throughout the 2015-2016 and 2016-2017 ski seasons with the primary objective to optimize the system for total nitrogen removal. Eight different combinations (schemes) of daily hydraulic and nutrient loading, dose frequency, effluent recycle, and depth of saturation of the first stage were tested. Average system removal was 93% and 95% for chemical oxygen demand (COD) and 70% and 75% for total nitrogen (TN) in 2016 and 2017, respectively, despite elevated influent concentrations of 930 mg x L -1 COD and 195 mg x L -1 TN. In addition, the system converted virtually all influent TN to nitrate. Both 1:1 and 2:1 (recycle to influent) ratios were effective as were saturation depths of 53 and 71 cm. At the 2:1 recycle ratio, the higher saturation level was superior at light hydraulic and constituent mass loadings while the lower saturation level was superior at higher loadings, but the differences were small. Overall, TN removal and nitrogen species transformations were linearly related to the mass load applied (surface area basis) over the range evaluated. In addition, the maximum removal capacity of the system was not exceeded during any scheme, thus the inherent removal capacity of the system is greater than evaluated. Nevertheless, the removal efficiencies of the VF TW from the past two seasons has shown that this technology can successfully perform secondary wastewater treatment in cold climates with efficient nitrogen removal and can exceed the regulatory requirements under which Bridger Bowl operates.Item Denitrification at the microscale in treatment wetlands(Montana State University - Bozeman, College of Engineering, 2015) Spengler, Justin Warren; Chairperson, Graduate Committee: Robin Gerlach; Anne Camper (co-chair)Treatment wetlands (TWs) have been in use for over three decades for wastewater treatment, agricultural water treatment, and some industrial wastes. Thousands of TWs exist for treating wastewater globally, but the microbial processes and controls in situ primarily responsible for water treatment are poorly understood. In this study, 16 separate model TW columns consisting of three plant groups and one non-planted group were fed synthetic post-secondary wastewater with half receiving no added carbon and half receiving 0.391 g L -1 as sucrose. Core samples were taken from each of the TW columns and separated into three distinct habitats (roots, gravel, particulates). Each habitat was assayed for its ability to produce N 2O, consume N 2O, and emit N 2O, as well as for denitrification gene abundances (nirS, nirK, and nosZ) and bacterial gene abundance (16S rDNA). The addition of organic carbon to the wetland was found to increase denitrification activity and gene copy abundance in non-root fractions, but organic carbon addition did not affect the root fraction. Plant presence within the TW was found to increase gas assay and gene abundance values in non-root habitats. Differences between three plant species were minor compared to differences attributed to carbon addition and plant presence. Of all habitats, gravel was found to have the highest denitrification activity and denitrification gene copy abundance relative to the number of 16S rDNA copies, as well as the highest ratio of N 2O produced to N 2O emitted. Implications for this study suggest the gravel and root fractions should be studied in further detail for their ability to accommodate denitrifying microbes.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 Removal of phenols from a refinery waste stream utilizing porous biomass supports in an aerated reactor(Montana State University - Bozeman, 1988) Center, Ray; Chairperson, Graduate Committee: Howard S. PeavyItem Adsorption of chloroform by soils in a continuous flow reactor(Montana State University - Bozeman, 1984) Karlsen, Barbara HeckmanItem Light-energized oxidation of organic wastes(Montana State University - Bozeman, College of Engineering, 1971) Sargent, Jerome WadsworthItem Recovery of copper by biopolymer gel and polymer vegetation by electrowinning and ion exchange technologies(Montana State University - Bozeman, College of Engineering, 1995) Kallepalli, Ramakrishna RajuBiopolymer gel beads of calcium alginate and alginic acid have high affinities for divalent metal ions such as Cu 2+. Hence they may be useful materials for recovering copper from aqueous solutions. The copper sorbed by the calcium alginate gel beads could be completely eluted and the metal recovered in a salable metallic form by using a combination of ion-exchange and electrowinning technologies. In such processes, the calcium alginate gel beads are fully regenerated. The resorption capacity of the gel beads did not decrease significantly during up to three sorption-desorption-electrowinning cycles. Distribution ratios of copper between the gel and liquid phases were measured using a batch method. Distribution ratios of copper for gel beads of calcium alginate ranged from 0.3 to 0.9 liter solution/gram dry sodium alginate [(mg Cu 2+ / gram dry sodium alginate)/(mg Cu 2+ / liter solution)]. Distribution ratios of copper for gel beads of alginic acid ranged from 0.47 to 0.84 liter solution/gram dry sodium alginate [(mg Cu 2+ / gram dry sodium alginate)/(mg Cu 2+ / liter solution)]. The equilibrium data were consistent with the ion-exchange reaction between cupric ions and calcium alginate/alginic acid. Maximum sorption capacities of the gel beads of calcium alginate and alginic acid were determined by comparing the experimental data with theoretical predictions. Maximum sorption capacities of the gel beads were found to be 5.21 X 10 -3 kmol/ kg dry sodium alginate and 4.11 X 10 -3 kmol/ kg dry sodium alginate for calcium alginate and alginic acid respectively. 3.2% sodium alginate in water was used to make the gel beads of calcium alginate and alginic acid. Scale up of the technology was studied in a fluidized bed reactor and electrowinning cell designed for this purpose. Calcium alginate gel beads were reused up to three times for absorption of copper after regeneration using ion exchange and electrowinning technologies. This technology reduced the influent copper concentration by 63%.