Matching Items (8)

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Understanding the Impacts of Building Design and Use on Potable Water Quality Through Enhanced Monitoring

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The intent of this dissertation was to advance the knowledge of the impacts of building design and use on the quality of the potable water. Fluctuations in water use by occupants and equipment can cause stagnant conditions that causes water

The intent of this dissertation was to advance the knowledge of the impacts of building design and use on the quality of the potable water. Fluctuations in water use by occupants and equipment can cause stagnant conditions that causes water quality decay such as loss of chlorine disinfectant, an increase in microorganism and pathogen growth, an increase in metals concentrations, and an increase in disinfection byproducts. The United States Environmental Protection Agency has drinking water standards for distribution systems, but these standards stop at the meter with exception of the Lead and Copper Rule. There are also building codes to ensure proper plumbing materials are used that come in contact with potable water. However, neither standards nor codes require building water quality monitoring. Therefore, monitoring the building potable water system is an important aspect of building water quality that is not done on a large scale.Chapter 2 investigated how water quality evolved in a “green”, multi-story, institutional building during the first 6 months of building life. The results indicated that Wi-Fi logins could be used to correlate occupancy activity and copper (Cu) concentrations in water. As occupancy activity increased, Cu concentrations decreased. However, chlorine (Cl2) residual (or free chlorine) was only measurable twice at two kitchen sinks via grab sampling during the duration of the 6-month study regardless of occupancy activity.
Chapter 3 provided improved understanding of how to carry out effective building water sampling (e.g., grab samples vs real time) and which water quality parameters were most influenced by the building water system during the first year of occupancy in relation to municipal water quality. The results showed the temperature (T), pH, UVA254, a surrogate for organic matter, cellular adenosine triphosphate (cATP), trihalomethanes (THMs), and Cu were always greater inside the building than at building entry while free Cl2 was always lower inside the building than at the building entry.
Chapter 4 investigated a remedial flushing program for three schools. Overall, the study showed the quality of water does change after a flushing event. Free Cl2 was reestablished, and metals concentrations decreased. However, equipment flushing, such as hot water heaters, may be necessary to fully remediate Legionella. Lastly, one-time flushing is most likely a temporary solution. A more routine approach to building flushing and monitoring may be necessary until normal or sustained occupancy resumes.

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Date Created
2021

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Ammonium and potassium removal from real hydrolyzed urine using natural zeolites

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The goal of this research was to study the effect of dilution on ammonium and potassium removal from real hydrolyzed urine. The performance of two natural zeolites, clinoptilolite and chabazite, was studied and compared with the help of batch equilibrium

The goal of this research was to study the effect of dilution on ammonium and potassium removal from real hydrolyzed urine. The performance of two natural zeolites, clinoptilolite and chabazite, was studied and compared with the help of batch equilibrium experiments at four dilution levels: 100%, 10%, 1% and 0.1% (urine volume/total solution volume). Further, the sorption behavior of other exchangeable ions (sodium, calcium and magnesium) in clinoptilolite and chabazite was studied to improve the understanding of ion exchange stoichiometry. Ammonium and potassium removal were highest at undiluted level in samples treated with clinoptilolite. This is a key finding as it illustrates the benefit of urine source separation. Chabazite treated samples showed highest ammonium and potassium removal at undiluted level at lower doses. At higher doses, potassium removal was similar in undiluted and 10% urine solutions whereas ammonium removal was the highest in 10% urine solutions. In general, chabazite showed higher ammonium and potassium removal than clinoptilolite. The result showed that ion exchange was stoichiometric in solutions with higher urine volumes.

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Date Created
2019

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Nitrogen Recovery from Human Urine by Membrane Processes

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This dissertation investigated the use of membrane processes to selectively separate and concentrate nitrogen in human urine. The targeted nitrogen species to be recovered were urea from fresh human urine and unionized ammonia from hydrolyzed human urine. Chapter 1 investigated

This dissertation investigated the use of membrane processes to selectively separate and concentrate nitrogen in human urine. The targeted nitrogen species to be recovered were urea from fresh human urine and unionized ammonia from hydrolyzed human urine. Chapter 1 investigated a novel two-step process of forward osmosis (FO) and membrane distillation (MD) to recover the urea in fresh human urine. Specifically, FO was used to selectively separate urea from the other components in urine and MD was used to concentrate the separated urea. The combined process was able to produce a product solution that had an average urea concentration that is 45–68% of the urea concentration found in the fresh urine with greater than 90% rejection of total organic carbon (TOC).Chapter 2 determined the transport behavior of low molecular weight neutral nitrogen compounds in order to maximize ammonia recovery from real hydrolyzed human urine by FO. Novel strategic pH manipulation between the feed and the draw solution allowed for up to 86% recovery of ammonia by keeping the draw solution pH <6.5 and the feed solution pH >11. An economic analysis showed that ammonia recovery by FO has the potential to be much more economically favorable compared to ammonia air stripping or ion exchange if the proper draw solute is chosen.
Chapter 3 investigated the dead-end rejection of urea in fresh urine at varying pH and the rejection of unionized ammonia and the ammonium ion in hydrolyzed urine by reverse osmosis (RO), nanofiltration (NF), and microfiltration (MF). When these different membrane separation processes were compared, NF is found to be a promising technology to recover up to 90% of ammonia from hydrolyzed urine with a high rejection of salts and organics.
Chapter 4 investigated the use of the RO and NF to recover ammonia from hydrolyzed human urine in a cross-flow system where both rejection and fouling experiments were performed. For both RO and NF, ammonia rejection was found to be 0% while still achieving high rejection of TOC and salts, and MF pretreatment greatly reduced the extent of fouling on the membrane surface.

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2020

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Advancing the Implementation and Adoption of Urine Diversion Systems in Commercial and Institutional Buildings in the United States: A Focus on Control of Urea Hydrolysis

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This dissertation focused on the implementation of urine diversion systems in commercial and institutional buildings in the United States with a focus on control of the urea hydrolysis reaction. Urine diversion is the process by which urine is separately collected

This dissertation focused on the implementation of urine diversion systems in commercial and institutional buildings in the United States with a focus on control of the urea hydrolysis reaction. Urine diversion is the process by which urine is separately collected at the source in order to realize system benefits, including water conservation, nutrient recovery, and pharmaceutical removal. Urine diversion systems depend greatly on the functionality of nonwater urinals and urine diverting toilets, which are needed to collect undiluted urine. However, the urea hydrolysis reaction creates conditions that lead to precipitation in the fixtures due to the increase in pH from 6 to 9 as ammonia and bicarbonate are produced. Chapter 2 and Chapter 3 describes the creation and use of a cyber-physical system (CPS) to monitor and control urea hydrolysis in the urinal testbed. Two control logics were used to control urea hydrolysis in realistic restroom conditions. In the experiments, acid was added to inhibit urea hydrolysis during periods of high and low building occupancy. These results were able to show that acid should be added based on the restroom use in order to efficiently inhibit urea hydrolysis.
Chapter 4 advanced the results from Chapter 3 by testing the acid addition control logics in a real restroom with the urinal-on-wheels. The results showed that adding acid during periods of high building occupancy equated to the least amount of acid added and allowed for urea hydrolysis inhibition. This study also analyzed the bacterial communities of the collected urine and found that acid addition changed the structure of the bacterial communities.
Chapter 5 showed an example of the capabilities of a CPS when implemented in CI buildings. The study used data mining methods to predict chlorine residuals in premise plumbing in a CI green building. The results showed that advance modeling methods were able to model the system better than traditional methods. These results show that CPS technology can be used to illuminate systems and can provide information needed to understand conditions within CI buildings.

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Date Created
2021

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Phosphate and Nitrate Removal from Impacted Waters by Combined Physical-Chemical and Microbiological Transformations

Description

Nutrient rich agricultural runoff is a major source of phosphorus (P) and nitrogen (N) loading to surface waters, resulting in eutrophication and harmful algal blooms. The most effective nutrient removal technologies often have cost, land, or operational requirements that limits

Nutrient rich agricultural runoff is a major source of phosphorus (P) and nitrogen (N) loading to surface waters, resulting in eutrophication and harmful algal blooms. The most effective nutrient removal technologies often have cost, land, or operational requirements that limits use in the decentralized areas that need it most. This dissertation investigated combined physical-chemical and microbiological technologies for combined P and N removal from nonpoint sources. Chapter 2 investigated the combination of basic oxygen furnace (BOF) steel slag and woody mulch for P removal by mineral precipitation and N removal by microbial denitrification. When combined with mulch in column experiments, slag with high fines content achieved complete P removal under unsaturated conditions. Batch experiments showed that microbial denitrification occurred under the highly alkaline conditions created by steel slag, but the timescale differential between P and N removal was a critical barrier to combining these treatment technologies. Chapter 3 evaluated a field-scale slag filter to treat agricultural tile drainage and lab-scale column experiments to provide insight on field conditions that impacted P removal. Increases in alkalinity had negative influences on P removal through inhibition of P mineral precipitation by BOF slag, while blast furnace (BF) steel slag was less impacted by alkalinity due to primarily adsorptive P removal. Regeneration strategies were identified based on water quality and slag type.Chapters 4 and 5 explored biological ion exchange (BIEX) as an option for addressing the timescale offset identified in Chapter 1. In Chapter 4 columns fed with dissolved organic matter (DOM) were not regenerated and over 50% DOM removal was observed, with the primary mechanism of removal identified as secondary ion exchange (SIEX)
between sulfate and DOM fractions with high affinities for ion exchange. Chapter 5 aimed to expand BIEX to N treatment through batch denitrification and adsorption experiments, which revealed a positive relationship between molecular weight of organic molecules and their ability to displace nitrate. This work shows that by having an improved understanding of impacted water characteristics, the information presented in this work can be used to select and implement effective treatment technologies for decentralized areas.

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Date Created
2022

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Urea Recovery from Human Urine Using Nanofiltration and Reverse Osmosis

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Global shortages of urea and unsustainable production of synthetic urea have caused concerns over the future of food production, automobile operation, and other processes. Urine is a waste product that could supplement synthetic urea production. This study utilizes polyamide reverse

Global shortages of urea and unsustainable production of synthetic urea have caused concerns over the future of food production, automobile operation, and other processes. Urine is a waste product that could supplement synthetic urea production. This study utilizes polyamide reverse osmosis (RO) and nanofiltration (NF) membranes in a cross-flow orientation to selectively recover urea from fresh human urine. Urea permeation experiments were conducted to determine the effects of urea stabilization via pH adjustment and membrane type on the production of a pure urea product. Fouling mitigation experiments were then conducted to determine the efficacy of microfiltration (MF) pretreatment on the reduction of the membrane fouling layer. The results showed that the NF90 membrane had advantageous performance to the BW30 RO and NF270 membranes, permeating 76% of the urea while rejecting 68% of the conductivity. Urine stabilization via acetic acid or sodium hydroxide addition did not inhibit membrane performance, signifying the use of pH 5 as a suitable pretreatment condition. Real fresh urine had higher rejection of constituents for NF90, suggesting the reduction of flux across the membrane due to interactions with organic material. MF pretreatment reduced foulant thickness and permeate flux loss but did not change the speciation of microorganisms. Finally, different urea-based products, such as fertilizers, biocement, and synthetic polymers, were suggested to show the potential of urine-recovered urea to reduce costs. The results from this work show the efficacy of using polyamide RO and NF membranes to supplement unsustainable synthetic production of urea with sustainably sourced urea from a waste product, human urine.

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Date Created
2022

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Potentiomics: Observations of In Situ and In Vitro Microbial Metabolic Activity Using Type IV Non-Selective Biofilm Membrane Potentiometric Sensors in Real-Time Applications.

Description

Potentiometric instrumentation technologies are widely used across many disciplines of science and engineering providing the ability to measure changes to specific environmental variables through various types of sensor electrodes and selective membranes. However, types I, II, and III potentiometric

Potentiometric instrumentation technologies are widely used across many disciplines of science and engineering providing the ability to measure changes to specific environmental variables through various types of sensor electrodes and selective membranes. However, types I, II, and III potentiometric sensor electrodes are limited by biofouling activity, membrane maintenance, grounding sensitivity, thermodynamic variables, and electromagnetic interference. Further, algorithms embedded into instrumentation hardware have impeded the usefulness of such measurements outside of highly controlled environments. Reliability of accurate measurement using these types of senor electrodes is limited to industrial and lab applications in chemistry and nominally active biological environments. Novel innovations in using exotic materials have improved the usefulness of Type II (e.g. tantalum-rubidium-doped titanium) and Type III (e.g. Nafion™ membranes) sensor electrodes, but those sensors are still limited to measuring a single selective parameter. This scope of work investigates utilizing a novel non-selective membrane, or naturally occurring biofilm membrane, as the active sensing surface of a graphite electrode as a new Type IV potentiometric sensor electrode (e.g., the MiProbE™) in biologically active environments. The analysis herein demonstrates decomposition of these non-selective signals into real-time metabolic activity, measurement of key biochemical processes and environmental condition parameters through classical mathematical analysis methods providing the basis of Potentiomics – the characterization and quantification of biochemical metabolic processes in highly dynamic non-equilibrium states.

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2022

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Novel Cosolvent Regeneration for Organic-loaded Anion Exchange Resin

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Hydrophobic ionizable organic compounds (HIOCs) like per- and polyfluoroalkyl substances (PFAS), certain pharmaceuticals, and surfactants have been detected in groundwater, wastewater, and drinking water. Anion exchange resin treatment is an effective process for removal of anionic contaminants from water. Spent

Hydrophobic ionizable organic compounds (HIOCs) like per- and polyfluoroalkyl substances (PFAS), certain pharmaceuticals, and surfactants have been detected in groundwater, wastewater, and drinking water. Anion exchange resin treatment is an effective process for removal of anionic contaminants from water. Spent anion exchange resins are conventionally regenerated with high alcohol by volume (ABV) methanol in solution with brine. While effective for regeneration of resins saturated with inorganic anions such as sulfate, nitrate, and perchlorate, HIOCs prove more resistant to regeneration. This research investigated the efficacy of using novel cosolvent solutions with brine to regenerate resins saturated with organic carboxylate and sulfonate anions to understand the effects cosolvent properties have on regenerative ability. Experiments were conducted on six PFAS compounds to evaluate trends in regeneration for three alcohols. For all PFAS species, equivalent ABV and brine solutions showed greatest regeneration with 1-propanol over ethanol and methanol. Experiments with the pharmaceutical sodium diclofenac were conducted showing similar regeneration of 75% methanol and 25% 1-propanol for equivalent salt concentrations and higher regeneration with 1-propanol than ethanol and methanol for equivalent ABV. A series of experiments with surfactant dodecylbenzene sulfonate determined that the key parameters to determine regeneration of the resin for an alcohol cosolvent solution were cosolvent volume fraction, molar mass, Kow value, solution ionic strength, and dielectric constant. Individual assessments on the cost-effectiveness, flammability, and sustainability of cosolvent solutions point to possible future experiments and opportunities for recycled distillery waste streams as regenerative solutions for anion exchange resin.

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Date Created
2022