Browsing by Subject "wastewater treatment"
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Item Development of an electron beam irradiation design for use in the treatment of municipal biosolids and wastewater effluent(2009-05-15) Lazarine, Alexis DawnThe need for pathogen-free water supplies has spurred investigations into the use of ionizing radiation for the treatment of wastewater effluent and municipal biosolids. The objective of this research was to develop an electron-beam irradiation scenario to effectively eliminate microbial pathogens from municipal biosolids and wastewater effluent. The Monte Carlo N-Particle (MCNP5) radiation transport code was used to simulate the irradiation scenario. Using MCNP5, dual electron-beam sources were modeled as planar surface sources above and below a stainless steel delivery trough containing either effluent water or one of two biosolids material compositions. A dose deposition analysis was performed to assess both the planar dose distribution and 25 depth-dose curves. In addition, a density perturbation study was performed to assess the variance in the dose deposition for different mass solids concentrations. To validate the MCNP5 code for this type of application, a benchmark study was performed. Two municipal biosolids materials and water were irradiated in plastic bags on a conveyor belt using a 10-MeV electron accelerator with the exit window below the material. The experimental configuration was modeled with the MCNP5 radiation transport code. Simplified and detailed models were created and analyzed. Lastly, an economic analysis was performed to assess whether this treatment method is a financially viable alternative to current wastewater treatment methods. Processing capacity was calculated for two accelerator specifications. These capacity rates in conjunction with the operating and capital costs per dry ton to irradiate the material were compared with existing data for electron beam processing of municipal biosolids. The cost breakdown was also compared with quoted costs for existing conventional methods. The models developed showed that the use of 10MeV electron-beam technology for the treatment of wastewater effluent and municipal biosolids is effective and economically feasible. The benchmarking study illustrated the accuracy of Monte Carlo simulation for this type of application. The method development process was shown to be adaptable for various material compositions and irradiation configurations.Item Wastewater Discharge, Nutrient Loading, and Dissolved Oxygen Dynamics in a Shallow Texas Bay(2014-05-07) Schroer, Lee AllenIn Oso Bay, a wastewater treatment plant acts as a source of eutrophication and may have measureable impact on the health of the bay. The objectives of this study were to create a model for modeling dissolved oxygen concentrations over time and to determine if eutrophication caused by the wastewater treatment plant is harmful to the bay. Continuous monitoring of environmental variables was carried out at 6 stations in Oso Bay over a 9-month period beginning in February and ending in December of 2013. Variables measured were water temperature (oC), pH, salinity (ppt), conductivity (mS), depth (meters), turbidity (nephilometric turbidity units), dissolved oxygen in both % saturation and concentration (mg/L), and chlorophyll-? concentration (?g/L). Grab samples of chlorophyll concentration (?g/L), total suspended solids (mg/L), and nutrient concentrations (?M) were also taken throughout the sampling period. Nutrients of interest were phosphate (PO_(4)), silicates (SiO_(4)), ammonium (NH_(4)), and nitrate+/-nitrite (NO_(x)). Hypoxia was observed at each of the stations in the bay and fluctuated on a diel cycle. Temperature, salinity, and temporal variability were significant factors in explaining the variance in dissolved oxygen concentrations (P < .0001) and were used to model dissolved oxygen variance (R^(2) = .7810). It is likely that the respiratory patterns of phytoplankton and bacteria also influence dissolved oxygen concentrations in Oso Bay, and that this is an indirect result of the discharge from the wastewater treatment plant.