No description available.

No description available.

Increasing urbanization in the US is leading to development or re-development of lands adjacent to solid waste facilities and these lands are being considered for residential communities and commercial projects. Thus, the potential for nuisance complaints against the pre-existing solid waste facility operations has become an increasing reality. The objective of this study was to develop a methodology to gather scientific and quantifiable data related to potential nuisances caused by landfills to determine setbacks and buffer zones near landfill and transfer station operations. Appropriate recommendations for these setbacks were made from case studies conducted at two landfills in Florida. The study involved making measurements related to odor, noise, litter and dust. Impact on housing prices was also evaluated by analyzing publicly available house price data. In this study volatile organic compound (VOC) concentration was used as a surrogate measure for gaseous impacts. The mass flux of VOCs was measured on the landfills using the dynamic flux chamber method. The ultimate purpose of flux measurements was to provide input data for dispersion modeling to analyze the extent of odor impact around the landfills, which is outside the scope of this study. Ambient measurements were also made around Landfill A for validating the dispersion model. Although there are no significant health and odor impacts caused by the landfill, higher background concentration extend 1.2-1.5 km from the landfill center on the Southeast side of the landfill. Litter from the road sides around the landfills was collected and catalogued based on size and material type. Litter count per site obtained for both landfills was less than the 2001 and 2002 state-wide counts. The difference was statistically significant. Noise measurements were made at landfills during incineration and landfilling. Based on average measurements (Leq) obtained at various distances from WTE facility and landfilling activity, and considering EPA recommended noise level of 55 dB(A) for a quiet neighborhood, a set back distance of 1.6-1.9 km was recommended. Impact on house prices near the landfills was done for four landfills in Florida. Analysis showed that three out of four landfills had significantly impacted the house price within 0.6-0.8 km from the edge of the landfill. Dust measurements were made at Landfill B using particulate samplers, quantifying the dust associated with landfilling. Measured values were below National Ambient Air quality Standard (NAAQ) for PM10. Finally, recommendations were developed to mitigate some of these nuisances

As U.S. landfills continue to grow in size, concerns about odorous gas emissions from landfills are increasing. For states that are expanding in population, such as Florida, odors from landfills are a major concern because new housing developments, needed to accommodate the rapid population growth, are creeping closer and closer to the existing landfills. As homes get closer to landfills, odor complaints are likely to become more frequent, causing landfill managers increased problems with public interactions. Odor buffer zones around landfills need to be established to give municipalities tools to help prevent the building of future homes too close to landfills. Using the latest air dispersion model, AERMOD, research predicted downwind odor concentrations from a Central Florida landfill. Accurate estimates of methane emissions throughout a Central Florida landfill were determined using a new technique developed as part of this research that uses hundreds of ambient air VOC measurements taken within a landfill, as receptors. Hundreds of point sources were placed on the landfill, and the standard Gaussian dispersion equations were solved by matrix inversion methods. The methane emission rates were then used as surrogates for odor emissions to predict downwind odor concentrations via AERMOD. By determining a critical zone around a landfill with regards to odor, stakeholders will be able to meet regulatory issues and assist their communities. Other beneficial uses from this research include: determination of existing gas collection system efficiencies, calculation of fugitive greenhouse gas emissions from municipal solid waste (MSW) landfills, and improved landfill gas management.

In an organism's natural environment, there are always an uncountable number of stimuli, and stimulus features, available to gain control over behavior. When these component stimuli are presented simultaneously, this new stimulus compound can occasion a previously unseen effect on behavior. Stimulus compounding is a method used to better understand how variables in stimulus features may impact the final effect on an organism's responding when presented with a stimulus compound. While stimulus compounding experiments are often conducted using intermodal tone and light stimuli, it is conducted far less often using intramodal stimuli, potentially due to the competing stimulus features of same-modality stimuli. Even less conducted research has been done using two odor component stimuli, despite the large impact odor has on many species' behavior. The purpose of this study was to conduct a stimulus compounding experiment using intramodal ambient odor stimuli in rats, to see what kind of effect a mixed odor compound would have on the subject's behavior. This was done using a wind tunnel designed operant chamber, where both subjects were trained to respond to independently presented odor stimuli. Following training a compound mixture of both component odors was presented to the subjects. The results of this study demonstrated an averaged effect on behavior, producing a response rate under the compound mixture that was intermediate to the response rates under each independent component stimulus. This may be due to several factors, including the efficacy of initial training procedures, the efficacy of the apparatus, and the merging of the component stimuli's features.

No description available.

No description available.

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.

Instant puddings were prepared using ultra-high-temperature (UHT) processed and conventionally (HTST) processed milk at 6°C and 23°C in six replicates of a 2X2 factorial design to determine the effect of milk type and temperature on apparent viscosity and gel strength of pudding. Apparent viscosity was estimated from linespread readings on separate 25 ml samples of pudding measured at 0, 5, 10, 15, and 30 minutes after preparation. Gel strength was determined from penetrometer readings on separate warm and refrigerated 100 ml samples of pudding measured at 15, 30, 60, and 90 minutes after preparation. Consumer evaluations of flavor and texture of the puddings were obtained as well as word descriptors of UHT milk by those consumers who had tried the product. A five-point hedonic scale of 1=dislike extremely to 5=like extremely was used by 200 consumers to register their perceptions of flavor and texture of the puddings. Apparent viscosity was greater with HTST milk, warm milk, and longer elapsed time. The combination of cold milk and shorter time was least viscous. Gel strength of refrigerated pudding was greater for HTST milk, cold HTST, and longer time. Nonrefrigerated pudding was firmer for HTST milk and cold milk. Shortest time resulted in softest gel strength, with no difference between other time periods. Although values from objective measures differed between puddings made with UHT and with HTST milk, consumer responses to the texture and the flavor of the puddings were similar for the four milk type by temperature variations. / M.S.

Most taste-and-odor problems in the United States are caused by algal blooms in rivers and reservoirs. In the past, most of the attention has been focused on the formation of geosmin and MIB by blue-green algae (cyanobacteria), which cause earthy and musty odors, respectively. Little work has been performed, however, on equally obnoxious odors caused by other golden-brown and yellow-brown algae which are responsible for fishy, grassy, floral, and melon odors. Additionally, the production of odorous compounds can occur upon oxidation of a nonodorous parent compound. The objective of this research was to determine the effect of three oxidants - chlorine, potassium permanganate, and chlorine dioxide - on solutions of pure odorous as well as nonodorous compounds and algal extracts containing a mixture of odor-related compounds. Oxidant dosages used were in the ranges expected during water treatment. Rashash (1994) identified several odor-causing compounds in pure cultures of golden-brown, yellow-brown, green, and blue-green algae. The compounds selected for oxidation during this study were isolated by Rashash (1994) and are as follows: isovaleric acid (rancid, dirty socks), β-cyclocitral (tobacco, grape), phenethyl alcohol (roses), myristic acid (odorless), palmitic acid (odorless), linoleic acid (odorless), and linolenic acid (watermelon). All seven compounds were oxidized and evaluated by a trained flavor panel for sensory analysis. Because the three oxidants used in this study produced substantial changes in the odors of linoleic acid and linolenic acid, test solutions buffered to a pH of 7 of linoleic acid and linolenic acid were further evaluated by Flavor Profile Analysis (FPA) for sensory determination and gas chromatography/mass spectroscopy (GC/MS) for quantitative measurement of odorous compounds. Volatile compounds produced by Synura petersenii (fishy/cucumber) were also analyzed and evaluated. When linoleic acid (odorless) was treated with potassium permanganate (0.25 mg/L, 1.0 mg/L, and 1.5 mg/L) and chlorine dioxide (1.0 mg/L and 2.0 mg/L), a grassy odor was produced at an FPA intensity of 2-4 (weak). The compound causing this odor was confidently identified from GC/MS analysis as n-hexanal. The compound 2,4-decadienal, which exhibits a frying odor, was also identified in oxidized samples and could contribute to off-odors. Chlorine dioxide and potassium permanganate at the same doses were also effective in eliminating watermelon odors in linolenic samples. Flavor Profile Analysis of samples treated with chlorine was inconclusive since chlorine and acetone, which was used as an organic solvent, produce an alcohol odor at an FPA intensity of approximately 2 (weak) which masked other odors present. Flavor Profile Analysis of oxidized Synura extracts indicated that the fishy odor was destroyed and cucumber or grassy odors were unmasked. Potassium permanganate at a concentration of 0.25 mg/L was effective in eliminating all odors in Synura culture samples. Chlorine and chlorine dioxide at concentrations of 2.0 mg/L and 3.0 mg/L, respectively, eliminated the fishy odor in Synura samples. In both cases, however, vegetation or grassy odors were detected at an FPA intensity of less than 2 (very weak). / Master of Science