Wastewater, recycled irrigation water, and agricultural runoff can contain high levels of pathogenic bacteria, which pose a threat to human and ecosystem health. The use of a bioreactor containing mycelial mats of filamentous fungi is a novel treatment technology that incorporates physical, biological, and biochemical processes to remove bacterial pathogens from influent water. Although a relatively new concept, fungal bioreactors have demonstrated the ability to dramatically reduce fecal coliform bacteria in water, but no studies have attempted to explicitly identify the bacterial pathogen removal mechanisms exhibited by the fungi. This study evaluated several different species of fungi for use in fungal bioreactor systems and aimed to identify the modes of action responsible for the removal of bacterial pathogens. The species evaluated were Daedaleopsis confragosa, Pleurotus eryngii, and Piptoporus betulinus. Experimental results showed that all species of fungi assessed were capable of removing E. coli in a synthetic water solution. Significant concentrations of hydrogen peroxide, an antiseptic, were produced by all species of fungi evaluated. The fungal bioreactors containing P. eryngii produced the highest concentrations of hydrogen peroxide, generating a maximum concentration of 30.5 mg/l or 0.896 mM. This maximum value exceeds reported minimum concentrations required to demonstrate bacteriostatic and bactericidal effects when continually applied, providing evidence that a major bacterial removal mode of action is the production of antimicrobial compounds. In addition to its promising application to improve water quality, fungal bioreactors are a low cost and passive treatment technology. The development a hyper-functional system could be a have a substantial impact on the use of recycled irrigation water and on the water/wastewater treatment industry, for both municipal and agricultural wastewater. / Master of Science

Raw water samples from nine utilities were received, and water-quality analyses, bench-scale water treatment, and chlorination were performed to determine the effectiveness of enhanced coagulation at removal of dissolved organic carbon (DOC) and organic halide precursors. Bench-scale treatment included: 1) baseline treatment, defined as the coagulant dose and pH at which the specific utility's water treatment plant was operating on the day the samples were collected, and 2) enhanced treatment, which was determined on the basis of bench-scale studies. Enhanced treatment is defined in the proposed Disinfectant/Disinfection By-Products (D/DBP) Rule as the coagulant dose at which a 10 mg/L increase in coagulant dose does not produce greater than a 0.3 mg/L decrease in dissolved organic carbon (DOC) or total organic carbon (TOC) concentration over the previous dose (Federal Register 1994). The treated samples were then chlorinated and analyzed for disinfection by-products (DBPs), including trihalomethanes (THMs) and non-purgeable dissolved organic halides (NPDOX). Specific objectives included: 1) an evaluation of the effectiveness of enhanced coagulation for TOC reduction, 2) determination of the effectiveness of surrogate parameters: such as raw water DOC and specific ultraviolet absorbance (SUVA); for predicting TOC removal by enhanced coagulation, and 3) determination of the relationship between DOC and NPDOX concentration in raw and treated waters. For all of the utilities, enhanced coagulation was effective at meeting the proposed TOC removal requirements contained in the D/DBP Rule, which range from 20 percent to 50 percent removal based on the alkalinity and TOC of the raw water. Raw water SUVA was the best indicator of the expected Toe removal by enhanced coagulation, with raw water SUVA values > 3.0 L/mg-m typically indicating greater TOC removal. Organic content was a good indicator of DBP formation. The average non-purgeable dissolved organic halogen formation potential (NPDOXFP) yields, based on DOC, were 155 μg as Cl⁻/mg DOC for raw water samples and ranged from 110- 138 μg as CI⁻/mg DOC for treated water samples. / Master of Science

The objectives of this research were to develop a broad spectrum method for the extraction, concentration, and analysis of drinking water disinfection by products using solid phase extraction (SPE), and to determine if this method had lower detection limits and less variability than the proposed liquid-liquid extraction method, EPA Method 551. The disinfection by products investigated were halogenated nitriles, ketones, and aldehydes. The SPE method extracted and concentrated samples using the C-18 Empore Extraction Disks, and desorbed the analytes with methyl-tert-butyl ether (MTBE) as a solvent. The results showed that with the SPE method the recoveries were low (0-50%) for most compounds, and the limit of detection (LOD) values were in the range of 0.2 to 50 ug/L, which were much higher than those for EPA Method 551. The variability was also higher than for EPA Method 551. The SPE method also appeared to be concentration dependent; the recoveries decreased as analyte concentration increased. Highly saline conditions (250 g/L NaCl) resulted in low recoveries and concentration dependencies for some compounds. Even though the SPE method was easier and faster, the lower method detection limit (MDL) values and lower variability made Method 551 more preferable. Further analysis of the SPE method using a new cyclohexyl disk was also recommended. / Master of Science

From observations of the field and laboratory operations, several ideas as to improvement of the construction and operation of the pasteurizer were conceived. / Master of Science

As the population in water stressed areas increases, it is critical that wastewater treatment plants (WWTPs) continue to replenish depleted water supplies, and serve as an alternative water source. WWTPs depend on microorganisms in activated sludge to remove pollutants from wastewater and therefore an understanding of how these microorganisms are affected by various conditions and pollutants is needed. Also, as consumer products and industrial processes evolve, so do the pollutants they discharge to wastewater. In order to keep pace with these changes, understanding the effects of emerging contaminants to WWTP processes is essential. The research herein assesses microbial community dynamics of the response of nitrifying microorganisms in activated sludge to variation in ammonia concentration and evaluates the impact of engineered nanoparticles on activated sludge microbial communities and other emerging pollutants, such as antibiotic resistance genes and disinfection by-products. In order to assess microbial community dynamics of the response of nitrifying microorganisms to removal of ammonia in the feed, nitrifying activated sludge reactors were operated at various relevant temperatures and the nitrifying microbial community was characterized using activity assays and bio-molecular techniques. We found that Nitrospira spp. were the dominant nitrifying microorganisms, exhibiting stable relative abundance across multiple trials and over a range of temperatures. These results indicate the possibility of comammox bacteria in the system and highlight the complexity of nitrifying microbial communities in activated sludge relative to past understanding. Both microbial and chemical impacts of engineered nanoparticles on WWTP processes were also investigated. Metagenomic analysis of DNA extracted from activated sludge sequencing batch reactors dosed with gold nanoparticles with varied surface coating and morphology indicated that nanoparticle morphology impacted the microbial community and antibiotic resistance gene content more than surface coating. However, nanoparticle fate was controlled by surface coating more than morphology. Disinfection by-product formation in the presence of nanoparticles during WWTP disinfection was assessed using silver, titanium dioxide, ceria, and zero valent iron nanoparticles. Silver nanoparticles were found to enhance trihalomethane formation, which was attributed to the citrate coating of the nanoparticles. These studies both raise concern over the relationship between engineered nanoparticles and other emerging concerns in WWTPs, and take a step towards informing nanoparticle design in a manner that limits their associated environmental impact. / Ph. D.

M.S.

Cobia (Rachycentron canadum) is a tropical marine fish, with increasing commercial aquaculture importance worldwide. One of the major limitations to intensive aquaculture is disease. Diseases spread rapidly in an aquatic environment and pose a major threat to the development and introduction of new species, such as cobia, in aquaculture. This is due to the necessity to use wild caught broodstock, which pose a greater threat to introducing disease to a facility. Bacteria of the genus Vibrio play a major role in the diseases of cultured cobia and other species of marine fish. The goal of this study is to reduce the incidence of disease in a population, by either eliminating the potential pathogen or increasing the resistance of the host. To reach that goal, a disinfection assay to evaluate the effectiveness of nine common aquaculture chemical disinfecting compounds was evaluated against two bacterial pathogens (Vibrio anguillarum and V. ordalii). Both bacterial species were susceptible to a variety of common disinfecting compounds including Chloramine-T®, chlorine, ethanol, iodine, Lysol®, Roccal®-D Plus, and Virkon-S®. In addition, both species showed a resistance to disinfection with formalin and tap water. The humoral immune response of cobia to vaccination with a commercially-available vaccine for Vibrio spp. was evaluated by an ELISA. There was a significant difference between control and vaccinated groups (P<0.0001), showing significant antibody production resulting from vaccination. / Master of Science

<p dir="ltr">People spend approximately 90% of their time indoors, where they are exposed to a wide variety of particle- and gas-phase air pollutants. The COVID-19 pandemic has intensified the chemical disinfection of high-touch surfaces in occupational workplaces and residential buildings. The use of chemical disinfectants may introduce more pollutants into the indoor environment. These intensive disinfection activities may lead to high human exposure to the released VOC mixtures and potentially adverse effects on the health of disinfection workers and occupants. Thus, it is critical to characterize the VOC mixtures and estimate human exposure during the building disinfection events with various disinfectant products and different disinfection cases and exposure scenarios. This dissertation aims to (1.) evaluate and characterize the VOC emissions during the building disinfections; (2.) assess the low-cost sensor performance to measure VOCs via the PTR-TOF-MS during building disinfections; (3.) compare the VOC measurements and human exposure between breathing zone and bulk air experiment setups; (4.) evaluate the impact of indoor emissions on human exposure during different usage cases of building disinfection.</p><p dir="ltr">To achieve these objectives, this thesis presents three studies based on a field experiment campaign conducted at the Purdue Zero Energy Design Guidance for Engineer (zEDGE) Tiny House in the fall of 2020. First, this thesis presents a study to evaluate the real-time performance of PID in sensing indoor VOC mixtures during building disinfection events through co-location measurements with a PTR-TOF-MS during spray-based disinfectants. The measurements demonstrated that the PID was successful in identifying VOC emission events during the application of the disinfectants. Thus, PIDs may be suitable for integration with building automation systems for ventilation control. The PID response was less than the PTR-TOF-MS response, suggesting that the PID could more efficiently detect many components of the emitted VOC mixtures. Detailed correlation analysis between the PID and PTR-TOF-MS responses provides a basis for improving the reliability of PIDs in estimating VOC concentrations through the application of product-specific correction factors.</p><p dir="ltr">Secondly, this thesis conducts an experimental case study to demonstrate the application of PTR-TOF-MS for mobile breathing zone (BZ) monitoring of VOCs in workplace environments during disinfection activities. Worker inhalation exposure to VOCs was evaluated by attaching the PTR-TOF-MS sampling line to the researcher’s BZ while the disinfection activity was carried out throughout the building. The results show significant spatiotemporal variations in VOC concentrations can occur in the worker’s BZ during multi-surface disinfection events. The application of high-resolution monitoring techniques, such as PTR-TOF-MS, is needed to advance the characterization of worker exposures and develop appropriate mitigation strategies for volatile disinfectant chemicals.</p><p><br></p><p dir="ltr">Lastly, this thesis provides a comprehensive evaluation study on human exposure to VOCs during PAA-based building disinfection events via real-time measurement and disinfection event modeling. The results revealed that PAA-based surface disinfection can lead to an excessive increase in PAA concentrations. BZ experiments demonstrated a spatiotemporal variation in PAA concentrations. The missing mass inhaled measured by the PAA monitor indicated that the human inhalation exposure identified by BZ experiments may be much higher than in bulk air (BA) experiments; thus, a mobile measurement in their breathing zones can better understand the occupants’ exposure to PAA during a building disinfection event. The disinfection event modeling indicated that PAA-based building disinfection may lead to excessive human exposure when using high dilution ratios and/or turning off mechanical ventilation. Such exposure could potentially leave a severe or even irreversible effect on occupant health. These findings suggested that a disinfection protection plan/protocol is necessary for workers, ensuring a required dilution for a disinfectant solution and enough ventilation rate for a safe PAA disinfection event. For the general public who may have difficulties developing professional disinfection procedures, pre-diluted disinfection products with a warning of turning on ventilation could be a more suitable alternative for PAA-based disinfection.</p>

INTRODUÇÃO: A limpeza prévia de endoscópios rígidos (ER) seguida de desinfecção de nível intermediário com álcool etílico a 70% p/v após o exame de endoscopia nasal é uma prática adotada em muitos serviços de otorrinolaringologia. A literatura atual, no entanto, recomenda a esterilização ou desinfecção de alto nível como o método de descontaminação mais aceito para produtos para saúde classificados como semicríticos. No entanto, há que se fazer distinção entre equipamentos de alta complexidade e sua invasividade como os endoscópios flexíveis com lumens longos e estreitos utilizados na endoscopia digestiva, daqueles de conformação simples sem lumens de baixa invasividade como os endoscópios rígidos utilizados em otorrinolaringologia. OBJETIVO: Avaliar a segurança da desinfecção de nível intermediário com álcool etílico 70% p/v, após limpeza prévia dos endoscópios rígidos utilizados em procedimentos clínicos de endoscopia nasal considerando a carga microbiológica recuperada após o uso. MÉTODO: Imediatamente após a realização do exame, uma gaze úmida foi utilizada para o arraste da carga biológica do endoscópio rígido, gerando as amostras do Controle Positivo e, após a aplicação do POP, um novo arraste para constituir as amostras do Grupo Experimental. Estas gazes foram inicialmente submetidas à sonicação e agitação imersas em soro fisiológico e em seguida a solução foi submetida a uma técnica de extração de carga microbiológica por filtragem por meio de uma Membrana de Celulose de 0,22um de poro que foi, em seguida, semeada nos meios de ágar Sangue, Chocolate, Sabouraud, Löwenstein-Jensen e Tioglicolato. Estes meios ficaram incubados em estufa a 37ºC ± 2ºC e avaliados, no máximo, até por 60 dias conforme o perfil de crescimento dos diferentes microrganismos de interesse; foram analisados de maneira quantitativa e qualitativa para identificação e classificação dos micro-organismos recuperados após as semeaduras. RESULTADO: Os resultados da análise estatística evidenciaram diferença significativa entre Controle Positivo e Grupo Experimental quando comparados em relação à presença de Streptococcus coagulase negativa (p < 0,001), Bacillus spp (p < 0,001) e Staphylococcus aureus (p=0,001). No Controle Positivo, foram encontradas presença desses micro-organismos respectivamente na seguinte frequência: 63,2%, 28,9% e 28,9%, enquanto que, no Grupo Experimental, não foi houve recuperação microbiana alguma. CONCLUSÃO: Os resultados desta pesquisa demonstram a eficiência, na prática diária, da desinfecção de nível intermediário dos endoscópios utilizados na otorrinolaringologia por meio da fricção com álcool etílico 70% p/v por 90 segundos, com protocolo de limpeza prévia / INTRODUCTION: Prior cleaning of rigid endoscopes (REs) followed by intermediate-level disinfection with 70% ethyl alcohol (w/v) after nasal endoscopy is a common practice in many otolaryngology services. Current literature, in turn, recommends high-level sterilization or disinfection as the most accepted decontamination method for health products classified as semi-critical. However, it is necessary to distinguish highly complex equipment according to their invasiveness, e.g., flexible endoscopes with long and narrow lumens used in digestive endoscopy and those with a simple conformation without lumens of low invasiveness, such as rigid endoscopes used in otorhinolaryngology. OBJECTIVE: To evaluate the safety of intermediate-level disinfection with 70% ethyl alcohol (w/v) after cleaning of REs used in clinical procedures of nasal endoscopy considering the microbiological load recovered after use. METHOD: Immediately after the test, a wet gauze was used to drag the biological load from the RE, generating positive control samples; after applying POP, dragging was carried out again to generate samples of the experimental group. These gasses were initially subjected to sonication and shaking while immersed in physiological saline; the solution was then subjected to the microbiological loading technique by filtration through a 0.22-um pore cellulose membrane and then cultivated on blood, chocolate, Sabouraud, Löwenstein-Jensen, and thioglycolate agar media. These media were incubated at 37ºC ± 2ºC and evaluated for up to 60 days, according to the growth profile of the different microorganisms of interest. A quantitative and qualitative analysis was performed for the identification and classification of microorganisms recovered after cultivation. RESULTS: The results of statistical analysis showed a significant difference between the positive control and experimental groups for the presence of coagulase-negative Streptococcus (p < 0.001), Bacillus spp (p < 0.001), and Staphylococcus aureus (p=0.001). In the positive control group, these microorganisms were found in the following proportions: 63.2%, 28.9%, and 28.9%, respectively, whereas in the experimental group, no microorganisms were recovered. CONCLUSION: The results of this study demonstrate the efficiency of the daily practice of intermediate-level disinfection of endoscopes used in otorhinolaryngology by means of treatment with 70% ethyl alcohol (w/v) for 90 seconds, using a previous cleaning protocol

Outbreaks of food-born illness associated with the consumption of unpasteurized juice and apple cider have resulted in a rule published by the U.S. Food and Drug Administration (FDA) in order to improve the safety of juice products. The rule (21 CFR120) requires manufacturers of juice products to develop a Hazard Analysis and Critical Control Point (HACCP) plan and to achieve a 5-log reduction in the number of the most resistant pathogens. Ultraviolet (UV) disinfection is one of the promising methods to reach this 5-log reduction of pathogens. The absorption coefficients of juices typically vary from 10 to 40 1/cm and can be even higher depending on brand and processing conditions. Thin film reactors consisting of two concentric cylinders are suitable for inactivating pathogens in juices. When the two concentric cylinders are fixed, the flow pattern in the gap can be laminar Poiseuille flow or turbulent flow depending on flow rates. If the inner cylinder is rotating, and the rotating speed of the inner cylinder exceeds a certain value, the flow pattern can be either laminar or turbulent Taylor-Couette flow. UV disinfection between concentric cylinders in laminar Poiseuille flow, turbulent flow and both laminar and turbulent Taylor-Couette flow was investigated experimentally and numerically. This is the first systematic study done on UV disinfection between concentric cylinders in all three flow patterns. The present work provides new experimental data for pathogen inactivation in each of the three flow patterns. In addition, the present study constitutes the first systematic numerical CFD predictions of expected inactivation levels. Proper operating parameters and optimum gap widths for different flow patterns are suggested. It is concluded that laminar Poiseuille flow provides inferior (small) inactivation levels while laminar Taylor-Couette flow provides superior (large) inactivation levels. The relative inactivation levels are: laminar Poiseuille flow < turbulent flow < laminar Taylor-Couette flow.