Målet med denna undersökning har varit att finna metoder för rening av struvitpåväxt i rör på Skövde biogasanläggning samt metoder för att undvika uppkomst av struvit. Detta för att man på anläggningen ska kunna öka verkningsgraden och fungera mer resursoptimerat för att på så sätt komma närmare en hållbar samhällsutveckling. Struvit (magnesiumammoniumfosfat hexahydrat) är ett vitt hårt mineral som vanligtvis förekommer i rör, värmeväxlare, pumpar och centrifuger på vattenreningsanläggningar och efter rötningsprocess på biogasanläggningar. Struvit fäller ut som en följd av bland annat pH, temperatur, koncentration och övermättnad. Även rörmaterial kan ha en påverkan på struvitfällning. Undersökningen har genomförts med hjälp av studiebesök samt analys av biogödsel och struvit på Skövde biogasanläggning. Detta för att ta fram den mängd struvit som kan fälla och vart på anläggningen detta sker. En enklare benchmarking har genomförts som har visat att struvitfällning på biogasanläggningar främst uppstår i värmeväxlare och att påväxten där är temperaturberoende. Material och kemikalier har undersökts för att ta fram metoder för rening och hindrande av uppkomst av struvit. Undersökningen har visat på att struvit främst uppkommer i värmeväxlaren och i rörkrökar på anläggningen och att detta är beroende av de pH, övermättnad, temperaturer och höga koncentrationer av fosfor, magnesium och ammonium som finns. Utifrån studien har en teori skapats om att mineralet först uppkommer i kammaren mellan rötkammare och mellantank. Undersökningen visar vidare på att de metoder som är mest effektiva för borttagning av påväxt struvit är att hacka loss mineralen alternativt byta ut rören. För att hindra att påväxt på rör sker rekommenderas att en kombination av metoder genomförs, vilka minskar energianvändningen på anläggningen och hindrar stopp i biogasproduktionen. Kemikalier bör användas om kristallbildning helt ska hindras. Dessa bör tillsättas i nämnda kammare. Till detta bör planerade underhåll ske för att minimera redan påväxt struvit. De rör som byts på anläggningen bör i främsta hand bytas mot plastmaterial. På så sätt kan anläggningen fungera mer resurseffektivt och onödig miljöpåverkan undviks. I studien har endast en grov kostnadsanalys kunnat genomföras. För att vidare understödja ovanstående metod rekommenderas därför en djupare ekonomisk analys genomföras. Denna bör även innefatta studier av kemikaliedos samt undersökning av kontrollplatser för planerade underhåll. / The goal with the study has been to find methods for cleaning and prevention of struvite at Skövde biogasanläggning (biogas plant). This to increase the efficiency and resource optimize the biogas plant and in that way get closer to a sustainable development of the society. Struvite (magnesiumammoniumphosphate hexahydrate) is a white, harsh mineral that commonly occurs in pipes, heat exchangers, pumps, and centrifuges at wastewater plants and after digestion processes at biogas plants. Struvite precipitates as a result of pH, temperatures, concentrations and supersaturation. Pipe material can also contribute. The study has been conducted through study visits and analyses of digestate and struvite at Skövde biogasanläggning to find the amount of struvite that can precipitate and where at the plant this happens. A simple benchmarking has been conducted, which shows that struvite precipitation at biogas plants mainly occurs in heat exchangers and that the fouling is temperature dependent. Materials and chemicals have been studied to find methods for cleaning and prevention of struvite. The study has shown that struvite mainly occurs in the heat exchanger and in pipe bends at the biogas plant and that it is dependent of the pH, supersaturation, temperature and high concentrations of phosphorous, magnesium and ammonium. A theory has been made from the study that the mineral first appears in the chamber between the digesters and heat storage tank. The study further shows that the most effective methods to clean fouling of struvite is to by hand chip the mineral alternatively replace the pipes. To prevent fouling of pipes a combination of methods is recommended, which minimizes the energy usage at the plant and prevent stops in the biogas production. Chemicals should be used if crystallization is to be completely stopped. The chemicals should be added in the above- mentioned chamber. Also planned maintenance should be conducted to minimize fouling. The pipes that are to be replaced should be replaced with pipes made of plastic materials. By doing this the resource efficiency increases and unnecessary environmental impact of the plant is avoided. The study has only included a rough cost analysis. To further support the above- mentioned methods a deeper economic analysis is recommended, which should include a study of chemical dosage and inspection sites for planned maintenance.

Microbial colonization on the surface of silicone rubber high voltage outdoor insulators often results in the formation of highly hydrated biofilm that influence the surface properties, such as surface hydrophobicity. The loss of hydrophobicity might lead to dry band formation, and, in the worst cases, flashover and failure of the insulator. In this work, the biocidal effects of various antimicrobial compounds in silicone rubber materials were determined. These materials were evaluated according to an ISO standard for the antimicrobial activity against the growth of aggressive fungal strains, and microorganisms that have been found colonizing the surfaces of outdoor insulators in several areas in the world. Several compounds suppressed microbial growth on the surfaces of the materials without compromising the material properties of the silicone rubber. A commercial biocide and thymol were very effective against fungal growth, and sodium benzoate could suppress the fungal growth to some extent. Thymol could also inhibit algal growth. However, methods for preservation of the antimicrobial agents in the bulk of the material need to be further developed to prevent the loss of the compounds during manufacturing. Biofilm formation affected the surface hydrophobicity and complete removal of the biofilm was not achieved through cleaning. Surface analysis confirmed that traces of microorganisms were still present after cleaning. Further, surface modification of the silicone rubber was carried out to study how the texture and roughness of the surface affect biofilm formation. Silicone rubber surfaces with regular geometrical patterns were evaluated to determine the influence of the surface texture on the extent of microbial growth in comparison with plane silicone rubber surfaces. Silicone rubber nanocomposite surfaces, prepared using a spray-deposition method that applied hydrophilic and hydrophobic nanoparticles to obtain hierarchical structures, were studied to determine the effects of the surface roughness and improved hydrophobicity on the microbial attachment. Microenvironment chambers were used for the determination of microbial growth on different modified surfaces under conditions that mimic those of the insulators in their outdoor environments. Different parts of the insulators were represented by placing the samples vertically and inclined. The microbial growth on the surfaces of the textured samples was evenly distributed throughout the surfaces because of the uniform distribution of the water between the gaps of the regular structures on the surfaces. Microbial growth was not observed on the inclined and vertical nanocomposite surfaces due to the higher surface roughness and improved surface hydrophobicity, whereas non-coated samples were colonized by microorganisms. / <p>QC 20151002</p>

Membrane biofouling is a common occurrence in water treatment plants that utilize reverse osmosis (RO). As bacteria and biofilm material build up on the membrane surface, it becomes more difficult for clean water to permeate through the membrane, and more pressure is required to produce the same amount of water. When pressures become critically high, membranes must be cleaned. This process is expensive in terms of chemical cost, labor, and downtime. Even after membranes have been cleaned, they can re-foul quickly if the cleaning did not effectively remove the biofilm. The water treatment plant in Dunedin, FL, which uses RO for treating groundwater, has experienced membrane biofouling since it began operation in 1992. Without the means to systematically evaluate a multitude of cleaning strategies on the bench scale, cleaning optimization must be conducted on the production skid level, which restricts the evaluation of alternative protocols. This problem is typical for many RO plants. The objectives of this project are: (1) using a multi-level and systematic approach, develop cleaning strategies for biofouled membranes that will lead to improved cleaning and decreased operational costs; (2) develop other cleaning strategies that will add to the scientific knowledge base; (3) quantify the effects of improved protocols; and (4) determine the policy implications of developed protocols in terms of cost suitability to Dunedin and elsewhere in Florida. This project consists of three phases, with phases progressively more similar to the water production environment. In the first phase, a series of bench tests were performed in the laboratory. Fouled membrane swatches were soaked and agitated in different cleaning solutions for different lengths of time, at different temperatures and pH. Protein and carbohydrate assays were then performed on both the cleaning solution and the membrane swatch to determine which conditions yield most complete removal of protein and carbohydrate from the membrane surface. Results indicate that carbohydrate removal does not appear to depend strongly on pH or temperature. Protein removal increases with increasing pH and is slightly greater at higher temperatures. The second phase of testing employed a 4"x6" stainless steel flat-sheet module in which cleanings were performed under different conditions to document corresponding changes in water flux and salt rejection. Operational parameters were based on pertinent literature and optimization results from Phase 1. Results indicate that water flux increases in response to cleaning at increasing pHs and increasing temperatures with best performances occuring after 30 minutes of cleaning. Salt rejection appears to decrease with pH. The most effective cleaning protocols, determined through trials in Phases 1 and 2, were put to the test again in Phase 3 where cleanings were performed on a specially constructed single-element cleaning system (for 8.5" x 40" elements), designed to clean a membrane element in isolation. This phase also served as final verification of new cleaning protocols before implementation on the production scale. Results from this phase were inconclusive due to mechanical problems. A multi-level, systematic cleaning evaluation leads to better understanding of the dependence of biofilm material removal and membrane performance on critical factors such as temperature, pH, time of cleaning, and chemical dose, which results in improved cleaning protocols and ultimately cost savings to RO water utilities such as Dunedin.

Cooperation is pervasive in nature but paradoxically also provides opportunity to cheaters. My dissertation involves the study of both cooperation and conflict in two species of Megalopta bees. Megalopta is a Neotropical genus of halictid bees whose biology is characterized by complex life cycles that can range from solitary to eusocial. These bees nest in dead wood and forage under dim light conditions. Megalopta’s nests are inhabited by an extensive array of organisms and each nest therefore constitutes a miniature ecosystem providing opportunities for cooperation and conflict, both within and between species. I first delineate the social structure of M. genalis and M. ecuadoria nests in several Panamanian populations and integrate the factors that play a role in the behavioral decisions of females when joining a social group or not. Within a kin-selection framework, I discuss how genetic relatedness plays a role in the formation of social nests. Second, I investigate the conflict between host bees and a congener social parasite, and I elucidate reproductive structures that are relevant for understanding the evolution of parasitism. Finally, I describe a cleaning mutualism between Megalopta bees and their mite associates. Bee-mite associations encompass a broad spectrum of interspecific interactions. Some bee-mites are thought to perform cleaning services for their hosts in exchange for suitable environments for reproduction and dispersal. Field observations and experimental manipulation reveal a significant correlation between the presence of mites and the absence of fungi inside the brood cells, as well as between the absence of mites and increased bee mortality. This study therefore provides evidence of the sanitary effect of mites in nests of Megalopta bees. This bee-mite association constitutes one of the few examples of terrestrial cleaning mutualisms. / text

Decorticated flax contains a significant amount of shive content, which limits applications of flax fibre. Separation of shives from the fibre is essential to improve the quality of flax fibre. Pneumatic method and a Sorter were implemented to meet the above objective. Terminal velocities of individual flax fibre and shive particles were investigated and their width, length, and mass were recorded. A sorting method was used for separation of short and long fibre for two grades of fibre: Grade 1 and Grade 2, with initial fibre purities of 51% and 15%, respectively. The ranges of terminal velocities for shive and fibre particles were 1.13 to 4.09 m/s and 0.51 to 1.07 m/s, respectively, which were significantly different. Fibre purity of approximately 80% for Grade 1 and 66% for Grade 2 were recorded from sorting, which were a significant improvement when compared to the initial purities. This study demonstrated the potential of the pneumatic and sorting methods for improving fibre quality. With the increase in resistant strains of microorganisms to antibiotics, researchers have started to explore plant parts to discover new antimicrobials. Since medieval times all portions of plants were used medicinally. Plant tissues, including stems, possess secondary metabolites (SMs), which have known antimicrobial properties. The purpose of this study was to investigate: the presence of antimicrobial compounds in stem extracts of canola, flax, hemp, and sweet clover; and study sorption-desorption behavior of their powdered stem material. GC-MS analysis of all extracts showed the presence of many SMs, including fatty acids, terpenoids, steroids, and sterols, etc. Many of the SMs found in the extracts have previously shown antimicrobial activity against a broad spectrum of organisms according to literature. Water sorption isotherms of stems showed a typical IUPAC Type II sigmoid curve similar to natural fibres. Equilibrium moisture content (EMC) of canola and sweet clover was significantly higher than flax and hemp at 95% RH, which were all higher than the fibre saturation point of wood (27%). The preliminary investigation via GC-MS showed promising results and water absorptivity results of stems can be used as the initial key property for many applications. / October 2015

Retail stores are understudied given the energy, occupant health, and potential sales impacts associated with poor indoor air quality (IAQ). There is also evidence of elevated pollutants in retail environments. This thesis is an exploration of the indoor air quality of retail stores. The first section of this thesis is a literature review on field investigations of the indoor air quality in retail buildings. Sixteen investigations report different measurements in 17 specific types of retail environments. Measurements vary depending on the specific investigation, but include VOCs, SVOCs, particles, microbiological species, and radon. When reported, indoor to outdoor ratios of almost all pollutants are greater than unity, suggesting the importance of indoor sources in retail environments. The second section of this thesis is an analysis of the whole store net emission factor for different retail environments. From the types of pollutants found in the retail store investigations, VOCs were the only pollutant group studied frequently enough to merit this analysis. The final section is an analysis of the potential for pollutant remediation strategies. Two methods, increasing air change rate and air cleaning, are considered with an analysis of the energy penalties associated with each. / text

Theatre is an art form that combines the art of storytelling with the visual arts. Every production begins with a blank canvas, and it is up to the director and a team of designers to discuss concepts and decide on an artistic vision for the piece. Skilled artisans work quickly as a team to produce the vision of the designer and director. During the production process waste is generated in the scene shop, props shop, costume shop, and rehearsal space. The products that are used to create the design can often contain harmful ingredients for both the artisan and the environment. No longer willing to ignore the responsibility that theatres have as stewards to the environment many artisans are leading the way by exploring safer practices and products. The research for this thesis is focused on the theatrical costume shop and examines dry cleaning, fabric painting and dyeing, and waste disposal. Alternatives to regular dry cleaning practices and commonly used and otherwise toxic products are available for a variety of processes we use in the theatre. For this study I conducted one hundred and sixty five surveys, ten interviews and a quality test amongst the dry cleaning alternatives in Austin, Texas. Three sets of seven different fabric samples were cleaned using the standard solvent and the alternative methods for dry cleaning. Four professional dyers and painters were interviewed about their dyeing process, disposal practices, and the impact that “green” products have on their work. I spoke with two experts working in wastewater about the impact dyes and paints have on wastewater treatment plants. Finally, I conducted an anonymous survey in 2010 to find out what new products or methods are in use amongst costume shop managers, dyers and painters, and production managers. / text

Wastewater reuse is fast becoming an imperative issue based on the developments in water/wastewater engineering coupled with increasing pressures on water resources. Trace organic compounds (TOrCs) that exist in water/wastewater, are a serious threat once they were released in the environment. During the past decade, there has been much progress toward understanding the occurrence, fate and toxicology of trace organic pollutants that enter the environment in treated wastewater. The objective of the first part of this research was to evaluate the combined effects of sequential anaerobic/aerobic digestion on residual TOrCs, concentrating on chemicals that are responsible for observed estrogenic/androgenic activities in biosolids. Full-scale digestion was simulated using bench-scale bioreactors in which the primary independent variables were retention time, temperature, and oxygen loading during aerobic digestion. Treatment-dependent changes in estrogenic/androgenic activity and concentrations of specific Endocrine disrupting compounds (EDCs) were measured. Results suggest that standard mesophilic anaerobic digestion increases the total estrogenic/androgenic activity of sludge while aerobic digestion was effective in the reduction of estrogenic/androgenic activity as a supplementary treatment stage. The second part of the study was focused on the fate of TOrCs and estrogenic activity in water and sediment of the Santa Cruz River, which is effluent dependent except during infrequent periods of rainfall/runoff in Tucson area. Several sampling campaigns were carried out from 2011 to 2013. Results suggest that some organic TOrCs, including those that contribute to estrogenic activity, were rapidly attenuated with distance and time of travel in the Santa Cruz River. Indirect photolysis of estrogenic compounds through the river might play an important role for the observation of estrogenic activity changes in the SCR. Hydrophobic TOrCs may accumulate in river sediments during dry weather periods. Riverbed sediment quality is periodically improved through storm-related scouring during periods of heavy rainfall and runoff. Wastewater effluent can be applied to the algal biodiesel industry based on regional water stress across the world. In the third part of the research, reclaimed wastewater was explored for this purpose, simultaneously satisfying the needs for water, macronutrients such as nitrogen and phosphorus, and micronutrients necessary for growth of microalgae. At the same time, algal growth in conventionally treated wastewater will improve water quality through the same nutrient removal processes and perhaps by lowering residual levels of trace organics that are an impediment to potable reuse. Results showed that metals levels in most municipal wastewaters are unlikely to disrupt growth, at least by metals tolerant microalgae like Nannochloropsis salina. Cells can grow without inhibition on nutrients from treated municipal wastewater or a centrate stream derived from wastewater treatment. The results also suggest while wastewater provides a suitable nutrient source for algal growth, there is simply not enough municipal wastewater available to support a meaningful biofuels industry without water recycling and nutrient recovery/reuse from spent algae. The last part of the dissertation was the application of water/wastewater treatment techniques, specifically advanced oxidation processes (AOPs) in other industrial sectors. In the integrated circuit production industry, chemical formulations used for megasonic cleaning typically contain hydroxides, peroxides and carbonates, which can affect particle removal efficiency and feature damage. The role of carbonates and ammonia in modulating the oxidation power of megasonic irradiated alkaline solutions through the scavenging of hydroxyl radicals by varying levels of carbonates, bicarbonates, ammonia and solution temperatures on net generation of hydroxyl radicals for applications in semiconductor industry was investigated in this study. The simulation of actual megasonic cleaning process was carried out at acoustic frequency of ~ 1 MHz and different power densities. Carbonate ions were better scavengers of hydroxyl radicals than bicarbonate ions. The effect of bulk solution temperature revealed that the rate of generation of hydroxyl radicals at a power density of 8 W/cm² increased with temperature from 10-30°C, which suggests an increase of transient cavitation with temperature.

Fluoride based chemical systems are widely used at various stages in microelectronic processing, particularly for wet cleaning and etching applications. Some examples include the use of semi aqueous fluoride (SAF) solutions in back end of line cleaning, the use of dilute HF solutions as etchants for SiO2 and HF-HNO3 or HF-H2O2 solutions as isotropic etchants for silicon. In this work, the use of fluoride based solutions for two applications relevant to semiconductor processing are considered.In the first part of the study, cleaning of post plasma etch residues generated during fabrication of copper damascene structures was investigated in semi aqueous fluoride (SAF) formulations based on dimethyl sulfoxide and ammonium fluoride. Formulations designed for residue removal should be able to remove the residue effectively, without causing critical dimension loss during the process cycle. A systematic evaluation of solution variables (solvent content and pH) was conducted and the extent of removal of model copper oxide films and selectivity over copper and carbon doped oxide (CDO) films were used as metrics to evaluate the formulations. Results of the study indicate that the presence of solvent is necessary to achieve reasonable etch selectivity over dielectric films. Additionally, a removal end point detection technique based on electrochemical impedance spectroscopy was developed, which could potentially help in the optimization of cleaning time with minimal dielectric loss. This method was applied to monitor the removal of copper oxide films as well as residue from patterned test structures.In the second part of the study, electrochemical formation of porous silicon films in hydrofluoric acid (HF) solutions was investigated, for potential applications in advanced packaging. Specifically, porous silicon formation in solution mixtures containing HF, acetic acid and peroxide, was studied. The effect of variables including current density, substrate resistivity, HF, acetic acid and peroxide concentration, on key porous film characteristics such as growth rate, porosity and microstructure, was explored. Addition of peroxide was found to significantly increase the porosity and growth rate of the film, as a result of enhanced chemical dissolution and films with porosities as high as 95% were obtained. Additionally, in solutions containing peroxide, a variety of microstructural features, such as nanopores, micron sized pores, truncated pyramidal structures and silicon needles were observed, under various fabrication conditions.

Robust and efficient cleaning procedures for protein A chromatography resins used for production of monoclonal antibody based biopharmaceuticals are crucial for safe and cost efficient processes. In this master thesis the effect of different cleaning regimes with respect to ligand stability of two protein A derived media, MabSelectTM and MabSelect SuReTM, has been investigated. A 96-well format has been used for preliminary screening of different cleaning agents, contact times and temperatures. NaCl as a ligand stabilizer during cleaning-in-place (CIP) was also included as a parameter. For optimal throughput and efficiency of screening, Rectangular Experimental Design for Multi-Unit Platforms; RED-MUP, and TECAN robotic platform have been utilized. For verification of screening, selected conditions were run in column format using the parallel chromatography system ÄKTAxpressTM. In the efficiency study, where a manual preparation of CIP solutions was compared with an automated mode performed in TECAN, the total process time ended up at eight hours versus three days respectively. However, the time measured included the learning process for the TECAN platform and for further preparations the automated mode is the superior choice. The study confirmed the higher alkaline stability of MabSelect SuRe compared to MabSelect. After exposure to 0.55 M NaOH during 24h MabSelect SuRe still retained 90% of the initial capacity. In contrast MabSelect had 60% of the initial binding capacity. When CIP with 10 mM NaOH was performed at 40 °C MabSelect reduced its capacity by half while MabSelect SuRe still had a binding capacity of 80%. The 96-well screening showed that an addition of NaCl during CIP had a significant positive effect on the stability of MabSelect, but needs to be verified on column format. The correlation between results from screening in 96-well filter plate and column format was good.