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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.
51

Removal Of Refractory Tkn From An Effluent Wastewater Using Sodium Ferrate

Lettie, Lucia 01 January 2006 (has links)
This research addresses refractory forms of nitrogen that, even with advanced biological nitrification-denitrification systems are not removed completely from domestic wastewater. TKN (Total Kjeldahl Nitrogen), ammonia plus organic nitrogen, is one of the forms to measure the levels of nitrogen present in effluent wastewaters. Ferrate, a strong oxidant, was used for the treatment of these nitrogen forms with the objective of producing nitrogen compounds that can be removed by subsequent biological processes. Bench-scale experiments were performed on effluent samples taken prior to chlorination from an Orlando, FL wastewater treatment facility, using a biological nutrient removal process. The samples were treated with doses of ferrate ranging from 1 to 50 mg/L as FeO4–2 under unbuffered conditions. TKN removal as high as 70% and COD removal greater than 55% was observed. The TSS production after ferrate treatment was in a range of 12 to 200 mg/L for doses between 10 and 50 mg/L FeO4-2. After an optimum dose of ferrate was determined, three bench-scale reactors were operated under anoxic conditions for 10 to 12 days, two as duplicates containing the treated effluent and one as a control with untreated sample. Two different doses of ferrate were used as optimum dose for these experiments, 10 and 25 mg/L as FeO4-2. The purpose of these reactors was to determine the potential for biological removal of remaining nitrogen after ferrate oxidation of refractory nitrogen. Treated and raw samples were analyzed for Total Kjeldahl Nitrogen (TKN) (filtered and unfiltered), chemical oxygen demand (COD) (filtered and unfiltered), total suspended solids (TSS), nitrate (NO3-N), nitrite (NO2-N), and heterotrophic plate count (HPC). As a result, more than 70% of the soluble TKN was removed by chemical and biological oxidation for a sample treated with a dose of 25 mg/L FeO4-2, and less than 50% when treated with 10 mg/L FeO4-2. For the control samples run parallel to the ferrate treated samples, a maximum of 48% of soluble TKN and a minimum of 12% was removed. A three-log increase was observed in heterotrophic bacteria numbers for both doses during the operation of the reactors. Sodium ferrate was found to be an effective oxidant that can enhance the biodegradability of recalcitrant TKN present in municipal wastewaters. As mentioned before this research was develop using batch reactor units at bench-scale, therefore it is recommended to follow the investigation of the biodegradability of recalcitrant TKN of a ferrate treated sample under continuous flow conditions so that results can be extrapolated to a full-scale treatment facility.
52

Pilot Study Of Nutrient Loading In A Wet Detention Lake

Gurr, Eric C. 01 January 2007 (has links)
Florida is surrounded by water, and its many internal lakes and rivers have long been recognized for their excellent fishing and boating. This notoriety draws land developers to the lake shores to establish residential and commercial infrastructure. This land development brings with it flood plain alteration, water level stabilization, and increased nutrients which cause adverse impacts to our lakes. In response, the United States Environmental Protection Agency (EPA) passed the Federal Clean Water Act (CWA) in 1972 which set the framework for the water quality standards for the entire United States. As a result of the CWA many point sources were eliminated, but in the process it became apparent that nonpoint source loads represented even more of a threat. To further study the physical and chemical characteristics of urban runoff the Nationwide Urban Runoff Program (NURP) was established in 1978. This research lead to a series of management options, named Best Management Practices (BMPs) which proposed various structural and non-structural methods to reduce nutrient loads. But the research and data collection on the effectiveness of these systems to remove nutrients is in its infancy. The main objective of this study was to generate accurate and effective water quality and water quantity data that future stormwater management decisions can be based upon. More specific, this study established automatic monitoring sites throughout the City of Kissimmee, Florida to determine the pollutant loadings into the tributaries of Lake Tohopekaliga. These monitoring sites are located such that inflows from outside the city limits can be isolated and external pollutant loads quantified. Also, additional internal monitoring sites were established to determine the pollutant loads of internal sections of the city. Data from these internal monitoring sites will also be used to determine the variable pollutant removal efficiencies and hydraulic fluctuations of natural, irregular riverine systems. The secondary objective of this study was to perform a pilot study using the discrete grab samples in tandem with the continuous hydraulic and hydrologic data from the monitoring stations. An existing lake within the project limits was chosen for the pilot study area. Monitoring stations are located at the influent and effluent sections of the lake which provided data on the hydraulic and hydrologic parameters. The pilot study determined the nutrient loads to and from the lake and checked for any seasonal variations in pollutant loading or removal efficiencies. For the purpose of this pilot study, only total nitrogen and total phosphorous were examined for two monitoring sites. The nutrient removal efficiency was performed using both the event mean concentration method and the summation of loads method to check for seasonal variation. There were no storm event concentrations available for used in this analysis, however, there were 25 discrete grab samples collected on a bi-monthly basis over a twelve month period. This data was used with corresponding five-minute rainfall and flow data from both the inflow and outflow points. The results of this study did not reveal any seasonal variation in the nutrient concentrations either flowing into or out from the lake. Although there were some relatively lower values in late spring, the concentration levels of total nitrogen did not seem to vary significantly from its mean value of 0.90 mg/l throughout the year. The concentration levels of total phosphorus did range from 0.02 mg/l to 0.48 mg/l, but not in relation to either season or flow volume fluctuations. The lake showed no net removals of total nitrogen and was actually found to be releasing total phosphorus to the downstream receiving waters. The findings of this study are limited due to the fact that the period of pilot study was only for twelve months and there were no rainfall events used in the analysis. Rainfall events are typically high sources of nutrient loads to a lake. The lower efficiencies were probably due to missing the actual higher nutrient load concentrations during the rainfall event. However, even considering the lack of event data, the nutrient removal efficiency for the pond was still low. This analysis did serve well as a basis for performing future analysis once additional data, including rainfall events, has been collected.
53

Comparison Of Traditional Standard Drainfield With Innovative B&g Treatment Bed For Nutrient Removal From Septic Tank Wastewater

Hossain, Fahim 01 January 2010 (has links)
Nowadays people are more alert about conservation of water and water scarcity. The amount of usable water is decreasing due to unavailability of pure water for day to day use. Both surface and groundwater is contaminated by untreated wastewater discharged from improper onsite wastewater treatment system, nutrient laden agricultural runoff and increasing use of fertilizer in fields. This elevated nutrient level is increasing the maintenance and operation cost of water treatment plant. So it is an important task to remove those nutrients from wastewater and other water bodies by applying environmental friendly process. In the USA, about 25% homes are still depending on on-site wastewater treatment (OSWT) due to unavailability of centralized treatment process. In Florida, OSWT is managed by the Florida Department of Health (FDOH). By realizing the importance of water conservation, USEPA already determined the maximum contaminant level (MCL) for nitrate and nitrite in water bodies. Many researches are conducted to evaluate the performance of EPA recommended treatment process (i.e. traditional standard drain field) for OSWT. The UCF research group also performed an experiment to understand the efficiency of traditional standard drain field. At the same time the research group developed an innovative wastewater treatment process named B&G treatment bed as a comparison with traditional standard drain field. This paper mainly focuses on performance of these two treatment processes. The B&G is a novel treatment process by its functionality for nutrient removal. The process generally used a media mixture developed by the research group of UCF. This mixture will act as organic carbon source to support denitrification process while nitrification process does not demand such carbon source. Evan it is observed that this mixture can remove nutrient by physical-chemical process. The recirculation sand filter (RSF) of traditional drain field is also filled by another mixture of media. Both media mixtures are developed by batch experiment in UCF laboratory. The performance of the B&G is compared with the traditional treatment process practiced in USA. These media mixtures can be good supporting media for microorganisms' growth and development. All the major nitrogen and phosphorus species removal is observed by collecting sample in a weekly fashion. The pathogens removal efficiency is also observed. The sample is analyzed by a certified laboratory (i.e. Environmental Research and Design, ERD) in Orlando, Florida to maintain the best quality of this research. The presence of microorganisms is identified by using PCR. The B&G drainfield is very effective for removing both nitrogen and phosphorus species from wastewater. It is also very efficient to remove pathogens too. Standard drainfield is very effective for pathogen removal but it cannot remove nutrients effectively. Nitrate removal in B&G drainfield is well compared to standard drainfield.
54

How the restoration of a wetland effects nutrient leakage: a case study on Fyrisån in Uppsala, Sweden.

Gummesson, Nellie January 2023 (has links)
Nutrient leakage into streams and rivers can lead to eutrophication, which negatively impact aquatic ecosystems. A commonly used tool to mitigate nutrient leakage is the implementation of wetlands into the polluted system. This study focuses on the levels of N and P in the river Fyris.n in Uppsala, Sweden, and the possible effects from restoration of a wetland near the river’s outlet. The results show a potential reduction of 41% and 45% for N and P respectively. The results point to a need for more wetlands further up in the catchment system to mitigate the nutrient load in the subcatchments, as the high nutrient levels there would not be affected by the proposed wetland. There are also several uncertainties due to the lack of reference material, and the results proves the need for further studies on this subject.
55

REDOX POTENTIAL (ORP) REGULATION OF NUTRIENT REMOVAL IN WASTEWATER TREATMENT PROCESSES AND THE STRUCTURE - FUNCTION ANALYSIS OF ACTIVATED SLUDGE FLOC

LI, BAIKUN 22 May 2002 (has links)
No description available.
56

Cultivation of Nannochloropsis salina and Synechocystis sp. PCC6803 in Anaerobic Digestion Effluent for Nutrient Removal and Lipid Production

Cai, Ting 27 August 2012 (has links)
No description available.
57

Alternative Waste Treatment System for Poultry Processing Plants

Roshdieh, Rana 30 December 2010 (has links)
The objective of this research was to design an alternative wastewater treatment system for turkey processing plants to recover energy and reduce N and P to allowable discharge levels. The objective included: 1. Determine the quantity and quality of biogas produced from the turkey processing wastewater (TPW) and COD reduction efficiency. 2. Design a waste treatment system and validate proof of concept for simultaneous P and N removal with a goal of attaining effluent concentrations of 0.1 mg/L and 4 mg/L, for P and N, respectively. A lab-scale complete mixed anaerobic digester was used for turkey processing wastewater (TPW) digestion and biogas recovery running for 6 months. Along with the anaerobic digester, a two-sludge system called A2N-SBR consisting of an anaerobic-anoxic sequencing batch reactor and an attached growth post-nitrification reactor was added for biological nitrogen and phosphorus removal running for 3 months. Biogas production yields of 778 + 89 mL/gVSadded and 951.30 mL/g COD were obtained through anaerobic digestion. Also, an energy balance was conducted on a pilot scale digester for a turkey processing plant with wastewater production of 2160 m3/d and using a combined heat and power (CHP) enginefor conversion of biogas to heat and electricity. Although the biogas yield achieved in a complete mixed reactor was relatively lower than yields obtained in previous studies using reactors such as UASB, still a complete mixed reactor can be a good choice for biogas recovery from TPW and can be used for codigestion with some specific turkey processing byproducts for biogas recovery. Nitrogen and phosphorus removal in the A2N-SBR system were 47% and 75%, respectively, and during the study the nitrogen and phosphorus removal mean concentration in effluent did not meet the nutrient limits specified in the objectives. Average TP and TN in the effluent were 3.2 mg/L and 137 mg/L, respectively. Throughout the study, the nitrification reactor biofilm was not completely developed. Incomplete nitrification and poor settling might be the reasons that quality obtained in effluent was low. To improve the process condition in A2N-SBR, online monitoring of pH, dissolved oxygen (DO) and oxidation reduction potential (ORP) can help to optimize each stage in the SBR and stages duration can be set based on the results. / Master of Science
58

A study of multi-stage sludge digestion systems

Kim, Jong Min 20 August 2010 (has links)
Various combinations of multi-stage thermophilic and/or mesophilic anaerobic sludge digestion systems were studied to evaluate their solids reduction, odor generation after centrifugal dewatering and indicator organism reduction in comparison to single-stage thermophilic and/or mesophilic anaerobic digestion systems. Pre-aeration of sludge in a thermophilic temperature was also tested followed by single or multi-stage anaerobic digestion systems. It was found that multi stage systems were capable of greater solids removal and placing thermophilic system in multi stage system enhanced indicator organism destruction below EPA Class A biosolids requirement. However, all the digestion systems in the study showed less than 3 log reduction of indicator organism DNA/g solids, which was much smaller than indicator organism reduction measured by standard culturing method. It was also found that the thermophilic anaerobic digestion system could increase organic sulfur-based odors from dewatered biosolids while placing a mesophilic digester reduced odors. It was exclusively observed from sludges containing high sulfate such as ones in this study. A combined anaerobic and aerobic sludge digestion system was also studied to evaluate their solids and nitrogen reduction efficiencies. The aerobic digester was continuously aerated to maintain dissolved oxygen level below 1 ppm and intermittently aerated. It was found that 90 % or more nitrogen removal was possible at the aerobic SRT greater than 3 days and the optimum aeration ratio could be determined. / Ph. D.
59

Impacts of the use of magnesia versus iron on mesophilic anaerobic digestion and odors in wastewater

Radhakrishnan, Kartik 25 October 2011 (has links)
Addition of iron to sewer lines for chemical phosphorus removal is widely practiced around the world. However, high dosage of iron may prove detrimental to the anaerobic digestion process and also lead to higher organic sulfur odors and deteriorating biosolids quality. The following research focuses on finding an alternative to the use of iron in wastewater systems by comparing the roles of iron and magnesium on mesophilic anaerobic digestion, the digested effluent characteristics and odors in biosolids. Three anaerobic digesters were operated, one serving as a control with no additives, and the other two having known doses of iron and magnesium added. Comparison of the effluent characteristics revealed an improvement in the overall performance of the magnesium amended digester (in terms of pH, solids and COD reduction, alkalinity and gas production) over the other two reactors, suggesting the benefits of magnesium addition. Both iron and magnesium were found to be effective in achieving high levels of phosphate removals and reducing nuisance odors in dewatered sludge cakes. / Master of Science
60

Carbon-efficient Wastewater Treatment Through Resource Recovery, Process Intensification, and Partial Denitrification Anammox

Wang, Jiefu 28 May 2024 (has links)
Facing the pressure of population growth and global warming, this dissertation provided an array of innovative carbon-efficient wastewater treatment technologies for resource recovery, process intensification, and anammox featured next generation biological nutrient removal (BNR) technologies. These technologies aim to supplant traditional carbon-intensive treatment processes with more sustainable alternatives. To this end, the dissertation first comprehensively reviewed what resources can be recovered from wastewater, and how these valuable resources can contribute to the carbon neutrality in water resource reclamation facilities (WRRFs) and help achieve sustainable society development. Then, the effect of mixed liquor recycle (MLR) configurations on the process intensification through continuous-flow aerobic granulation was explored in plug flow reactors. The results demonstrated that MLR configuration could hinder the sludge granulation, but the hindrance could be alleviated to some extent by its location change. In order to eliminate the energy consuming MLR, endogenous denitrification was taken advantage through a synergistic integration with partial nitrification, partial denitrification anammox (PdNA), and enhanced biological phosphorus removal (EBPR). This idea was tested in a pilot setup treating real primary effluent under highly variable influent conditions and low temperatures. The results showcased substantial carbon savings while meeting the stringent effluent requirements. To take a deeper dive into the PdNA performance and the underlying mechanisms, two parallel pilot-scale moving bed biofilm reactor (MBBR) treatment trains fed with methanol and glycerol, respectively, were operated in a local WRRF. Their efficacies in achieving stringent nutrient removal targets and carbon savings were compared. The impacts of operational conditions on the mechanisms and performance were elucidated. In the culmination of this dissertation, a sidestream process intensification and resource recovery technique, namely thermal hydrolysis pretreatment (THP) enhanced anaerobic digestion (AD), was experimented to compare the efficiencies between thermophilic and mesophilic AD when integrated with THP. To sum up, this dissertation not only advanced our understanding of carbon-efficient wastewater treatment processes but also laid the groundwork for their practical implementation, contributing to the global effort towards sustainability. / Doctor of Philosophy / Wastewater treatment consumes 3-4% of the energy produced in the U.S. and contributes to approximately 1.6% global greenhouse gas emissions. This dissertation aims to advance a series of carbon-efficient technologies specifically tailored for sustainable wastewater treatment. To this end, a variety of valuable resources that can be recovered or reused in wastewater treatment plants was firstly reviewed. Then, an advanced technology that can turn dispersed bacteria into bacteria aggregates was tested with real wastewater in a local wastewater treatment plant. Although these bacteria aggregates allow more wastewater to be treated with less small footprint, which was great, it was realized from this study that the formation of these bacteria aggregates was hindered by the nitrate water recycle which has been commonly practiced for using influent carbon for nitrogen removal. This nitrate water recycle consumed excessive energy for its high flow rate. To save this energy, a novel bioprocessing design was developed to eliminate the need for this nitrate water recycle by using carbon stored in bacterial cells. This new design also incorporated phosphorus recovery capacity and a low carbon nitrogen removal technique into one consolidated system to create an all-in-one solution to meet the stringent wastewater treatment requirement. This low carbon nitrogen removal technique harnessed a special group of bacteria that can use ammonia to reduce nitrite to nitrogen gas. Hence, only minor carbon source needs to be provided to reduce nitrate to nitrite for these bacteria to utilize. Two types of carbon sources, namely methanol and glycerol, were compared in a pilot-scale study to understand their efficiencies in generating nitrite. Results indicated that although both types of carbon sources can work, methanol is better suited for low strength wastewater treatment. These results provided an engineering basis for the full-scale application of the technology in the same wastewater treatment plant where the pilot study was performed. Besides liquid treatment, a carbon efficient solid treatment technology was also studied. The bottleneck constraining the rate of sewage sludge conversion to flammable menthane gas was identified, which provided engineering guidance for the design of the solid treatment process that can destroy more sewage sludge within smaller reactor spaces. In essence, this dissertation offers promising solutions for modern wastewater treatment plants to achieve low carbon wastewater treatment without compromising the treatment performance.

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