This dissertation examines African colonization and Native removal colonization schemes and their relationship to the development of states carved out of the Northwest Territory. Colonization advocates sought to expunge the nation of slavery, free blacks, and native peoples to make a white republic. This research contends that colonization promoted racial nationalism by campaigning for a safe and homogenous nation free of slavery, ‘degraded’ free blacks, and dangerous Native Americans. It explores the execution and afterlives of American projects for African colonization, through the American Colonization Society, and Native Removal in the Old Northwest. It examines the rhetoric and procedures related to the colonization of Native Americans in the West and free blacks to Liberia in which government officials, journalists, settlers, businessmen, missionaries, and clergy in Ohio, Indiana, and Illinois traded in fears of racial degradation and national security as a means to generate fiscal support and positive public opinion for legislation and policies that attempted to create a white republic. Colonizationists appropriated imperial relocation solutions to the domestic problems of black freedom and Native sovereignty that they construed as prohibitory to national expansion and development. Ventures to deport Native Americans and African Americans successfully constructed them as dangerous aliens within the nation that validated their exclusion. In their resistance African Americans, Native Americans, and their allies adapted, fled, petitioned, ridiculed, and negotiated with colonizationist endeavors to maintain residence in the Midwest. The fictions of colonization, driven by its rhetoric, required new constructions about black and Native degradation to justify the calls for their removal. / History

<p> Early pregnancy in mammals can be disrupted by numerous stimuli. In particular, exposure to males which did not sire the litter disrupts early pregnancy in previously inseminated female mice. This is known as the Bruce effect. Evidence suggests that this effect is mediated by chemical emissions (pheromones) from the males. Castration of the males eliminates the effect whereas testosterone replacement restores it. This has suggested that androgen-dependent male accessory glands might be responsible. In particular, the preputial, vesicular and coagulating glands seem likely candidates for subserving the Bruce effect since they have been implicated in a variety of social behaviors.</p> <p> In these experiments, inseminated females were each housed below either 1) two males which had undergone preputial gland removal or, 2) two males which had undergone vesicular-coagulating gland removal or, 3) two males which had undergone preputial, vesicular and coagulating gland removal or 4) two males which had undergone sham surgery. In each case, males which had undergone gland removal disrupted pregnancy in inseminated females to the same extent as did intact males. Histology showed no regeneration of the glands. These results suggest that none of these major androgen-dependent male accessory glands is responsible for pheromonal emissions involved in the Bruce effect.</p> / Thesis / Master of Science (MSc)

Heavy metals are a growing environmental concern as they are unable to be metabolized in the environment, leading to bioaccumulation in the food chain and impacting human health. Treating heavy metals is difficult and expensive. Current methods include precipitation (which generates sludge that is costly to dispose of) or requires the use of a membrane, which fouls and requires regeneration. Microbial electrolysis cells (MECs) represent an alternative for treating heavy metal contaminated wastewater. Reactor components are cheap, and operation requires only a small amount of electricity. The electrically active biofilm oxidizes organics in the wastewater while transferring electrons first to the anode, then to the cathode, where aqueous metals are reduced to a solid deposit, a mechanism called electrodeposition. Few studies have been conducted to investigate the best operational conditions for heavy metal removal in MECs. In this study, the effects of hydrodynamics, applied voltage, and initial metal concentration on heavy metal removal mechanisms are investigated, and the best operational practices are determined on a high level. Mixing in the cathode chamber increased electrodeposition by 15%, decreased the cathode potential by -0.06 V, and increased current generation between 10-30%. Increasing the applied voltage from 0.6 V to 1.2 V increased electrodeposition by 22%. With both mixing and higher voltage applied, 93.35% of cadmium was removed from the catholyte in 24 hours. Although high voltage application maximized electrodeposition for short-term treatment, long-term treatment indicated lower applied voltage resulted in healthier MEC reactors, better overall metal recoveries, along with a more stable cathode potential. / Thesis / Master of Applied Science (MASc)

This dissertation reports the design of a process (patent pending) to remove iron from acid mine drainage (AMD) without the formation of metal hydroxide sludge. The system includes the oxidation of ferrous iron in a packed bed bioreactor, the precipitation of iron within a fluidized bed, the removal of manganese and heavy metals (Cu, Ni, Zn) in a trickling filter at high (>9) pH, with final neutralization in a carbonate bed. The technique avoided the generation of iron oxyhydroxide sludge. In the packed bed bioreactor, maximum substrate oxidation rate (R_,max) was 1500 mg L⁻¹ h⁻¹ at dilution rates of 2 h⁻¹, with oxidation efficiency at 98%. The half-saturation constant (similar to a Ks) was 6 mg L⁻¹. The oxidation rate was affected by dissolved oxygen below 2 mg L⁻¹, with a Monod-type Ko for DO of 0.33 mg L⁻¹. Temperature had a significant effect on oxidation rate, but pH (2.0 to 3.25) and supplemental CO₂ did not affect oxidation rates. Iron hydroxide precipitation was not instantaneous when base was added at a OH/Fe ratio of less than 3. Induction time was found to be a function of pH, sulfate concentration and iron concentration, with a multiple R² of 0.84. Aqueous [Al (III)] and [Mn (II)] did not significantly (α = 0.05) affect induction time over the range of concentrations investigated. When specific loading to the fluidized bed reactor exceeded 0.20 mg Fe m⁻² h⁻¹, dispersed iron particulates formed leading to a turbid effluent. Reactor pH determined the minimum iron concentration in the effluent, with an optimal at pH 3.5. Total iron removals of 98% were achieved in the fluidized bed with effluent [Fe] below 10 mg L⁻¹. Further iron removal occurred within the calcium carbonate bed. Heavy metals were removed both in the fluidized bed reactor as well as in the trickling filter. Oxidation at pH >9 caused manganese to precipitate (96% removal); removals of copper, nickel, and zinc were due primarily to sorption onto oxide surfaces. Removals averaged 97% for copper, 70% for nickel and 94% for zinc. The treatment strategy produced an effluent relatively free of iron (< 3 mg/L), without the formation of iron sludge and may be suitable for AMD seeps, drainage from acidic tailings ponds, active mine effluent, and acidic iron-rich industrial wastewater. / Ph. D.

Ph. D.

Low dissolved oxygen (DO) biological nutrient removal (BNR) is becoming a viable option to improve the energy efficiency of BNR. To properly model and design BNR processes for low DO operation, it is critical to fully understand how nitrifier, denitrifier, and polyphosphate accumulating organism (PAO) oxygen kinetics adapt in a shift from traditional DO operation (2 mg O2/L or more) to low DO operation. Research characterizing how oxygen kinetics shift over time in activated sludge biomass adapting to low DO is limited. Therefore, a method to characterize oxygen kinetics for nitrifiers, denitrifiers, and PAOs simultaneously is lacking. Here a method was developed to simultaneously measure the oxygen kinetics of nitrifiers, denitrifiers, and PAOs. This method, termed the SND and P-Uptake Oxygen Kinetics test, was able to estimate the ammonia oxidizing bacteria (AOB) oxygen half-saturation coefficient, ammonia maximum removal rate, denitrifier oxygen inhibition coefficient, total inorganic nitrogen (TIN) maximum removal rate, PAO oxygen half-saturation coefficient, phosphorus maximum uptake rate, and a simultaneous nitrification and denitrification (SND) optimum operation point. Three tests were conducted on the Virginia Initiative Plant (VIP) BNR Activated Sludge Pilot while it was operating at a process DO of 2 mg O2/L, and one test while it was operating at 1.5 mg O2/L. The measurements among the three initial tests showed high similarity in their parameter estimates. Estimated oxygen half-saturation and oxygen inhibition coefficients were compared to current suggested ranges and were within the expected magnitudes. At 2 mg O2/L, denitrifier oxygen inhibition coefficients and PAO oxygen half-saturation coefficients were estimated to be remarkably low here, under 0.4 and 0.1 mg O2/L, respectively. AOB oxygen half-saturation coefficients were variable here in the range of 0.62 to 2.57 mg O2/L, seeming to vary with available ammonia concentrations. Upon comparison with a previously developed respirometric test for nitrifier oxygen kinetics, termed the Declining DO test, the AOB oxygen half-saturation coefficient from the SND and P-Uptake Oxygen Kinetics test and the Declining DO test, when both were conducted on the VIP BNR Pilot, showed a similar trend. This provided validation for the AOB oxygen kinetics here and the usefulness of the test developed here. Additionally, measuring and plotting AOB and denitrifier oxygen kinetics together produced an intersection point where ammonia removal rates were equal to TIN removal rates. This intersection point was an optimum point for SND during the conditions of the test. This method can be used to characterize and track oxygen kinetic changes in a BNR system adapting from high to low DO. / Master of Science / Aerating biological processes in wastewater treatment plants is necessary to facilitate nitrogen and phosphorus removal but is extremely costly. Traditional dissolved oxygen concentrations in these processes are 2 mg O2/L or higher. Operating processes with low dissolved oxygen (DO) concentrations, less than 1 mg O2/L, can cut costs significantly. However, designing processes at low DO concentrations requires knowledge of how microorganisms utilize substrate with lower oxygen availability and how substrate utilization develops when gradually decreasing the DO concentration in a process. Here, a method was developed to measure the parameters describing the relationship between substrate utilization and DO concentration for the microorganisms responsible for nitrogen removal (nitrifiers and denitrifiers) and phosphorous removal (polyphosphate accumulating organisms). Additionally, the method provides an optimum DO setpoint for simultaneous nitrification and denitrification (SND) during testing conditions. This method, termed the SND and P-Uptake Oxygen Kinetics test, was able to estimate the following parameters simultaneously: ammonia oxidizing bacteria (AOB) oxygen half-saturation coefficient, ammonia maximum removal rate, denitrifier oxygen inhibition coefficient, total inorganic nitrogen (TIN) maximum removal rate, PAO oxygen half-saturation coefficient, and phosphorus maximum removal rate. Three tests were conducted on the Virginia Initiative Plant (VIP) BNR Activated Sludge Pilot while it was operating at a process DO of 2 mg O2/L, and one test while it was operating at 1.5 mg O2/L. The measurements among the three initial tests showed high similarity in their parameter estimates. Estimated oxygen half-saturation and oxygen inhibitions coefficients were compared to current suggested ranges and were within the expected magnitudes. Upon comparison with a previously developed test for nitrifier oxygen kinetics, termed the Declining DO test, the AOB oxygen half-saturation coefficient from the SND and P-Uptake Oxygen Kinetics test and the Declining DO test when both were conducted on the VIP BNR Pilot showed a similar trend, providing validation for the usefulness of the test developed here.

Anaerobic digestion of wastewater sludge has widely been in application for stabilization of sludge. With the increase in hauling cost and many environmental and health concerns regarding land application of biosolids, digestion processes generating minimized sludge with better effluent characteristics is becoming important for many public and wastewater utilities. This study was designed to investigate the performance of anaerobic-aerobic-anaerobic digestion of sludge and compare it to anaerobic-aerobic digestion and single stage mesophilic digestion of sludge. Experiments were carried out in three stages: Single-stage mesophilic anaerobic digestion (MAD) 20d SRT; Sequential Anaerobic/Aerobic digestion (Ana/Aer); and Anaerobic/Aerobic/Anaerobic digestion (An/Aer/An). The Anaerobic/Aerobic/Anaerobic digestion of sludge was studied with two options to determine the best option in terms of effluent characteristics. The two sludge withdrawal options were to withdraw effluent from the anaerobic digester (An/Aer/An – A) or withdraw effluent from the aerobic digester (An/Aer/An – B). Different operational parameters, such as COD removal, VS destruction, biogas production, Nitrogen removal, odor removal and dewatering properties of the resulting biosolids were studied and the results were compared among different processes. From the study, it was found that An/Aer/An – B (wastage from aerobic reactor) provided better effluent characteristics than An/Aer/An – A (wastage from anaerobic reactor), Ana/Aer or conventional MAD. The study also shows that the Anaerobic/Aerobic/Anaerobic (An/Aer/An, with wastage from the aerobic or anaerobic digester) digestion of the sludge can improve the biosolids quality by improving the dewatering capabilities, with lower optimum polymer dose, reduced CST and increased cake solid concentration, and reduce the odor generation from the biosolids. Both An/Aer/Ana – A and An/Aer/An – B gave 70% VS removal, compared to 50% with single MAD and 62% with only Ana/Aer. COD removal of both An/Aer/An – A and An/Aer/An – B was 70%, while it was 50% and 66% for single MAD and Ana/Aer respectively. In the aerobic reactors of Ana/Aer and An/Aer/An - B, nitrification and denitrification with removal of nitrogen was observed. The An/Aer/An – B system had more ammonia and TKN removal (70%) than Ana/Aer (64%). The effluent from each stage was analyzed for dewatering ability, cake solid concentration and odor production potential. Compared with a single Ana/Aer system, the extra anaerobic step in An/Aer/An – A and – B reduced polysaccharides in the effluent. The Ana/Aer system released less protein than the conventional MAD system and the addition of the second anaerobic step - especially with system An/Aer/An – B (discharge from aerobic reactor) - greatly reduced protein, resulting in improved dewaterability and less polymer demand. An/Aer/An (both of the options: A and B) had lower CST than single MAD (both 15d and 20d SRT) and Ana/Aer. Compared to Ana/Aer, a reduction of 52% for An/Aer/An – A and 20% for An/Aer/An – B in polymer dose requirement was observed, indicating improved dewatering characteristics. The An/Aer/An – B has higher biosolid cake concentration than MAD or Ana/Aer. The results showed that An/Aer/An (both options: A and B) biosolid had lower odor generation potential than single MAD (15d and 20d SRT) or Ana/Aer. Of all the stages,the An/Aer/An – A and – B system, generated odor which peaked at shorter time and lasted for shorter duration of time. / Master of Science

The increased demand for advanced techniques in anaerobic digestion over the last few years has led to the employment of various pre-treatment methods prior to anaerobic digestion to increase gas production. These pre-treatment methods alter the physical and chemical properties of sludge in order to make it more readily degradable by anaerobic digestion. The thermal hydrolysis process has been used in several treatment plants around the world, but none currently operate in the US. Thermal hydrolysis causes cell walls to rupture under the effect of high temperature and high pressure and results in highly solubilized product which is readily biodegradable. The performance of the process was evaluated for a treatment plant located in Dallas, TX. The performance assessment was based on various characteristics including pH, solids removal, COD removal and gas production. The study was conducted in two phases to investigate the effect of change in mesophilic temperature (37°C and 42°C) and the effect of solids retention time (SRT) (15 days and 20 days). Thermally hydrolyzed combined (1:1) primary and waste activated sludge was fed to a Thermal Hydrolysis (TH) anaerobic digester and its performance was compared to a conventional mesophilic anaerobic digester receiving non pre-treated sludge. The thermal hydrolysis pre-treatment was found to be more effective as compared to the conventional anaerobic digester. The efficiency of the process varied slightly with increase in temperature but the change in SRT was seen to have a greater impact on the digester's performance. The pre-treatment technique was observed to deliver the best results at a 20 day SRT. / Master of Science

This study focuses on deposition processes from sediment laden buoyant river plumes in deltaic regions. The goal is to experimentally examine the effects of various physical phenomena influencing the rate at which sediment is removed from the plume. Previous laboratory and field measurements have suggested that, at times, sedimentation can take place at rates higher than that expected from individual particle settling (i.e., C{W}_{s}). Two potential drivers of enhanced sedimentation are flocculation and interfacial instabilities. We experimentally measured the sediment fluxes from each of these processes using two sets of laboratory experiments that investigate two different modes of instability, one driven by sediment settling and one driven by fluid shear. The settling-driven and shear-driven instability sets of experiments were carried out in a stagnant stratification tank and a stratification flume respectively. In both sets, continuous interface monitoring and concentration measurement were made to observe developments of instabilities and their effects on the removal of sediment. Floc size was measured during the experiments using a separate floc camera setup and image analysis routines. Results from the stratification tank experiments suggest that the settling-driven gravitational instabilities do occur in the presence of flocs, and that they can produce sedimentation rates higher than those predicted from floc settling. A simple cylinder based force balance approach adopting the concept of critical Grashof number was used to develop a model for the effective settling velocity under settling-driven instabilities that is a function of sediment concentration in the plume only. Results from the stratification flume experiments show that under shear instabilities, the effective settling velocity is greater than the floc settling velocity, and increases with plume velocity and interface mixing. The difference between effective and floc settling velocity was denoted as the shear-induced settling velocity. This settling rate was found to be a strong function of the Richardson number, and was attributed to mixing processes at the interface. Conceptual and empirical analysis shows that the shear-induced settling velocity is proportional to U{Ri}^{-2}. Following the experiments, analyses were made among contributions of different mechanisms on the total deposition rate, and the locations that the various mechanisms may be active in the length of a plume. This analysis leads to a conceptual discretization of a plume into three zones of sedimentation behavior and Richardson number. The first zone is the supercritical near-field plume with intense interface mixing. Zone two represents the subcritical region where interface mixing still occurs, and zone three is the high Richardson number zone where mixing at the interface is effectively nonexistent. In zones one and two, individual floc settling and shear-induced settling mechanisms play the major roles in removing sediment from the plume. While, shear-induced settling rate was found to be maximum near the river mouth, its share of the total settling rate increases in the crossshore direction, since sand and large particulates deposit near the inlet and only small particles (with relatively low settling velocity) remain as the plume propagates. The third zone, starts when the interfacial mixing diminishes and leaking commences. / Ph. D.

Conventional desalination plant, municipal water supply and wastewater treatment system are among the most electricity-intensive facilities. Microbial Desalination Cell (MDC) has emerged as a promising technique to capture the chemical energy stored in wastewater directly for desalination, which has the potential to solve the high energy consumption issue in desalination industry as well as wastewater treatment system. The MDC is composed of two critical components, the electrodes (anode and cathode), and the ion-exchange membranes separating the two electrodes which drive anions migrate towards the anode, and cations migrate towards the cathode. The multiple components allow us to manipulate the configuration to achieve most efficient desalination performance. By coupling with Donnan Dialysis or Microbial Fuel Cell, the device can effectively achieve boron removal which has been a critical issue in desalination plants. The uncertainty of water quality of the final desalinated water caused by contaminant back diffusion from the wastewater side can be theoretically explained by two mechanisms, Donnan exchange and molecule transport which are controlled by bioelectricity and concentration gradient. Scaling and fouling is also a factor needs to be taken into consideration when operating the MDC system in real world. With mathematical modeling, we can provide insight to bridge the gap between lab-scale experiments and industrial applications. This study is expected to provide guidance to enhance the efficiency as well as the reliability and controllability of MDC for desalination. / Ph. D.