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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

Physicochemical and biological treatability study of textile dye wastewater

Gorgone, Christine Ann 02 May 2009 (has links)
The textile industry discharges a highly colored wastewater characterized by high organic levels. Industrial wastewater with these characteristics can be harmful to receiving streams and municipal plants, and must be treated prior to discharge. In this project, a yam dyeing facility was studied that uses biological treatment followed by chemical coagulation to treat their highly colored wastewater prior to discharging to the local river. Occasionally, color, organic, and metal concentrations exceed the effluent discharge limits set by the state. In this research project, many physical, chemical, and biological treatment processes were attempted on the facility's wastewater to determine the most economical and efficient way to treat the wastewater. Initially, the wastewater was segregated into eight waste streams and characterized. These waste streams included three dye waste streams (acid dye, premetallized dye, and cat-acid dye), three rinse water waste streams (acid rinse water, premetallized rinse water, and cat-acid rinse water), a boiler water waste stream and a combination of dye, rinse, and boiler wastes called the combined waste stream. Chemical coagulation, oxidation, and adsorption were attempted on several of these waste streams with limited success. Ferric chloride and the polymer Color Katch 50 were the most effective chemicals used on dye waste streams, producing color removals greater than 90%. Aerobic biological treatment was attempted on several waste streams in continuous flow and batch tests. Batch tests indicated that the combined waste stream did not require the addition of supplemental nutrients for biological treatment and that at least a five day hydraulic residence time (HRT) was needed for maximum color and organic removals. Two day HRT, continuous-flow reactors receiving combined wastewater were very unstable and failed to biologically treat the waste. Increasing the residence time to seven days improved biological treatment. Soluble COD removal from the combined wastewater was about 93% and color removal was about 80% in the seven day reactor. A seven day HRT, continuous-flow reactor receiving a combination of rinse waters and boiler water was also successful. Eighty-four percent of the soluble COD and up to 70% of the color was removed from this waste combination. Color Katch 50 was used to remove residual color from the effluent of the seven day HRT reactors. On average, color in the combined effluent was reduced from 1,826 ADMI units to 163 ADMI units, and color in the rinse and boiler water effluent was reduced from 581 ADMI units to 356 ADMI units. / Master of Science
232

Batch Studies on the Biological Denitrification of Wastewater.

Dawson, Robert Nathaniel 11 1900 (has links)
<p> This dissertation examines the influence of the process variables, organic carbon concentration, nitrate concentration, pH, organism concentration, and temperature, on the rate of denitrification of dominant batch cultures of Pseudomonas denitrificans. The aim of the work was to determine which of the first four variables were important in controlling rate, and whether significant interactions existed between variables. As well, the ability of these typical bacterial denitrifiers to operate at low temperature conditions was to be ascertained. </p> <p> The experimental procedure indicated that pH and carbon concentration are the major influences on the unit denitrification rate a well as the overriding factor temperature which profoundly influences any bacterial process. Organic carbon concentration controls the rate up to the point where the stoichiometric requirements for nitrate reduction and the carbon needs for new cell growth are satisfied. A broad pH optimum within the normal range experienced in most wastewater treatment conditions was demonstrated. The temperature dependancy of the unit denitrification rate was shown to follow an Arrhenius relationship between 3ºC and 27ºC. As well, for the simplified system investigated the unit rate was independent of nitrate concentration. </p> <p> The dominant culture was related to mixed cultures of activated sludge to provide an estimate of the denitrifying rate of activated sludge on a similar simple batch system. </p> / Thesis / Doctor of Philosophy (PhD)
233

Biological Fluidized Bed Denitrification of Wastewater

Stephenson, Joseph P. 03 1900 (has links)
<p> A half-order kinetic model (8-48 mg NO3+NO2-N/l), coupled with a temperature dependency described by the Arrhenius relationship (4°-27° C), adequately described biological denitrification of municipal wastewater in a pilot scale fluidized bed reactor. Biofilm support media (activated carbon or sand) and hydraulic flux (0.25-1.7 m^3/m^2·min) were not found to be significant factors in controlling denitrification rate within the reactor. Control of biofilm thickness on the support media was essential for satisfactory operation of the process; excess thickness contributed to elutriation of media and attached biofilm. Under similar influent wastewater conditions, the fluidized bed process was capable of equivalent NO3+NO2-N removal in about one-tenth of the time necessary in a suspended growth or a rotating biological contactor (RBC) process. Temperature dependency of the NO3+NO2-N removal rate appeared to be less than the dependency in a suspended growth or a RBC process, but similar to the dependency observed in a packed column.</p> / Thesis / Master of Engineering (MEngr)
234

Microparticles in freshwater bivalves chronically exposed to wastewater effluent in the Grand River, Ontario, Canada

Robson, Emily January 2023 (has links)
A thesis submitted to the School of Graduate Studies in partial fulfilment of the requirements for the degree of Master of Science in the graduate academic unit of Biology / Microparticles enter aquatic environments through many sources, including wastewater treatment plants (WWTPs), but their uptake by aquatic organisms is poorly understood. Freshwater bivalves accumulate multiple contaminants, making them potential bioindicators for MP pollution. This study aims to understand the abundance and characteristics of microparticles that accumulate in wild bivalves. Samples were collected from 5 locations along the Grand River (Ontario, Canada) in 2021-2022, including 3 municipal WWTPs where both an upstream and downstream site were sampled. At each site, fingernail clams (Sphaeriidae, n=5 composite samples), flutedshell mussels (Lasmigona costata, n=10), and surface water (n=3) were sampled. Within the mussels, the gill, digestive gland, and hemolymph tissues were targeted and compared. Microparticles were isolated and quantified via stereomicroscopy but have not yet been confirmed as plastic; as such, they will be referred to herein as microparticles. Fibers were the dominant morphology and clear, blue, and black were the most common colours, but there were some differences among sites and sample types. Most microparticles were between 80 μm and 1 mm in length. Fingernail clams contained the highest microparticle counts per mass of tissue at 35.5 ± 29.4 microparticles/g, mussel tissues ranged from 4.3 ± 4.2 microparticles/mL to 6.5 ± 8.1 microparticles/g, and water samples contained the lowest counts at 0.0055 ± 0.0028 microparticles/mL. Elevated microparticle counts at downstream sites were only seen in mussel gills and not other bivalve tissues. Surface water samples did not show elevated counts downstream of the WWTPs and microparticle exposures were similar across sites. This study provides baseline data for future monitoring and informs toxicity studies to fully assess the risk of microparticles to vulnerable freshwater bivalves and other aquatic organisms. It also suggests microparticles in freshwater bivalves are coming from sources in addition to WWTPs and are ubiquitous in the Grand River. / Thesis / Master of Science (MSc) / Microplastics are found in nearly every environment, especially freshwater ecosystems. These plastics come from a variety of sources, and this study focuses on assessing the characteristics of microparticles in freshwater clams and mussels (bivalves) that have been exposed to municipal wastewaters. Bivalves and water samples were collected from 5 locations along the Grand River (Ontario, Canada) in 2021-2022, and microparticles were extracted and analyzed from each sample. Fibers were the most abundant type of microparticle, with colours consisting mostly of clear, blue, and black. Clams had the highest number of microparticles per mass of tissue collected and the lowest counts were found in water samples. Higher microparticle counts were only seen in one (mussel gill) of the four tissues from bivalves collected downstream of wastewater outfalls. This study provides baseline data on microparticle characteristics in freshwater bivalves and will guide future studies on the toxicity of microparticles to these animals.
235

Using Wastewater-Based Epidemiology to Study Chlamydia Occurrence on a College Campus

Chin Quee, Jessie E 01 January 2023 (has links) (PDF)
Chlamydia is a sexually transmitted disease caused by Chlamydia trachomatis, commonly affecting sexually active college-aged adults. Presently, opportunistic testing, self-testing, and information campaigns are methods to screen vulnerable populations and raise awareness about chlamydia. Chlamydia remains underdiagnosed and undertested due to a lack of participation by individuals who may have been exposed to it. Wastewater-based epidemiology is a rising biomonitoring tool that detects the presence of disease- and drug-specific biomarkers in a community's wastewater. In this study, wastewater-based epidemiology was used to detect the presence of C. trachomatis on the University of Central Florida campus. Wastewater samples were collected from two locations on campus from January 2022 to December 2022. The samples were pasteurized and filtered. DNA was extracted from the filters and was subsequently quantified using qPCR. C. trachomatis was detected at both sites of the UCF campus, with peaks corresponding to periods of the academic semester at which students arrived on campus or had fewer academic responsibilities. It was concluded that wastewater-based epidemiology provided a low-cost and non-invasive tool to notify the public of potential chlamydia outbreaks and encourage testing. Exploration in wastewater-based epidemiology should continue in research of C. trachomatis detection.
236

Assessing the Relationships Between Onsite Wastewater Treatment System Microbial Communities, System Design, and Environmental Variables.

DeVries, Jacob January 2021 (has links)
A Thesis Submitted to the School of Graduate Studies in Partial Fulfilment of the Requirements for the Degree of Master of Science. / Onsite wastewater treatment systems may be improved by altering the design and environmental variables that affect microbial community composition. However, the two most common methods of examining microbial composition through metagenomic sequencing (16S and shotgun sequencing) produce different taxonomic identification results according to microbial community composition and the analytical methods in use. To identify discrepancies between these two sequencing methods, we analyzed the effect of environmental and tank design variables on onsite-wastewater treatment system microbial communities sequenced using both 16S and shotgun sequencing. Shotgun and 16S sequencing produced different results when examining genera-level taxonomic richness, quantifying the effect of system design and environmental variables on community similarity, and identifying differentially abundant taxa between system types. Results were consistent when subjectively examining patterns of community similarity and when examining genera-level taxonomic diversity above 0.1% relative abundance. Identifying methods that produce similar results between 16S and shotgun sequencing supports the reliable analysis of and optimization of OWTS processes. / Thesis / Master of Science (MSc) / Onsite-wastewater treatments systems such as household septic tanks are vital tools for managing wastewater. However, the microbial ecosystem which digests waste within septic tanks contains unknown interactions that can alter the rate of waste digestion. We used two DNA sequencing methods to assess how microbial communities within septic tanks responded to the tank design and surrounding environment. We then compared results produced by the two sequencing methods. The response of microbial communities to tank design and the environment differed between the two methods. However, the two methods both indicated that one system design produced a more variable microbial community.
237

Wastewater Irrigation in Freezing Conditions and the Impacts to Runoff Water Quality and Soil Freezing

Griffin, Joshua E. 18 May 2015 (has links)
No description available.
238

Evaluating Opportunities to Improve Resource Efficiency of Conventional Wastewater Treatment Using the Alga Cladophora glomerata

Szabo, Adam R. 27 September 2012 (has links)
No description available.
239

STRUVITE ACCUMULATION DURING THE USE OF RECLAIMED MAGNESIUM HYDROXIDE IN WASTEWATER TREATMENT

GURUSAMY, ROOPSINGH 11 October 2001 (has links)
No description available.
240

Evaluating the Performance of Sand/Gravel Bioreactors in Treatment of High Strength, High Salinity Wastewater

Chen, Feng 26 September 2016 (has links)
No description available.

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