<p> This work examines the feasibility of continuous biological nitrification and denitrification for nitrogen removal from municipal wastewater. Pilot plant'studies were conducted using a rotating biological contactor (RBC) for nitrification and upflow packed columns for denitrification. Of primary interest were the effects of temperature on the systems. </p> <P> It was found that an Arrhenius model adequately described nitrification rates measured over a range of temperatures from 7 degrees C to 250 degrees C. Direct comparison of the Arrhenius Activation Energies determined for the RBC and a two stage activated sludge system with intermediate clarification showed that nitrification in the RBC was less temperature sensitive than in the activated sludge process. At 10 degrees C, roughly 20 mg/hr·m^2 (0.10 lb/day•1000 ft^2 ) of ammonia as nitrogen was removed from the system. </p> <p> The rate of denitrification in the packed column reactors displayed great variability. The temperature dependency of the data could not be characterized by an Arrhenius model or any other simple relationship. Although significant nitrate removal was observed at all temperatures between 5°C and 25°C, severe short circuiting due to solids accumulation tended to limit minimum nitrate effluent concentrations to 1 or 2 mg N03^-N/~. </p> / Thesis / Master of Engineering (MEngr)

Anaerobic digestion (AD) of corn thin stillage (CTS) offers the potential to reduce corn grain ethanol production energy consumption. This thesis focuses on results collected from AD of CTS at mesophilic temperatures in batch and by down-flow fixed film reactor. Experiments conducted include a series of biochemical methane potential (BMP) assays that investigated the digestion of CTS as the sole carbon source at a variety of food-to- microorganism ratios with and without acclimated biomass, under co-digestion conditions and also with the addition of supplemental nutrients. Additional BMP assays were conducted which investigated the potential to reduce fresh water consumption by using of digested effluent for substrate dilution. Continuous studies employed two 28L down-flow stationary fixed film reactors to examine. Chemical oxygen demand and volatile solids removal efficiencies greater than 85% were achieved up to an organic loading rate of 7.4 g TCOD/L/d and hydraulic retention time of 5 days.

Anaerobic digestion (AD) of corn thin stillage (CTS) offers the potential to reduce corn grain ethanol production energy consumption. This thesis focuses on results collected from AD of CTS at mesophilic temperatures in batch and by down-flow fixed film reactor. Experiments conducted include a series of biochemical methane potential (BMP) assays that investigated the digestion of CTS as the sole carbon source at a variety of food-to- microorganism ratios with and without acclimated biomass, under co-digestion conditions and also with the addition of supplemental nutrients. Additional BMP assays were conducted which investigated the potential to reduce fresh water consumption by using of digested effluent for substrate dilution. Continuous studies employed two 28L down-flow stationary fixed film reactors to examine. Chemical oxygen demand and volatile solids removal efficiencies greater than 85% were achieved up to an organic loading rate of 7.4 g TCOD/L/d and hydraulic retention time of 5 days.

No description available.

Based on a diverse consortia of research completed within the last 15 years, it has been found that Pharmaceutical Compounds (PCs) are present in detectable levels within a variety of environmental matrices, including tap water. This is largely attributed to anthropogenic activities as humans are the majority consumer of PCs. As a result, the primary method of disposal is via wastewater pathways resulting from human excretion of ingested PCs. Based on past research into PC fate via the wastewater treatment process, only limited biotic and abiotic transformations are achieved – most PC’s are detected in the effluents of WWTP’s. This suggests that improving the removal of PCs during the wastewater treatment process provides a promising strategy for limiting the conveyance of PCs to the environment. Historically, studies regarding PC fate in WWTPs have predominantly focused on the activated sludge process. However, fixed film (biofilm) wastewater treatment technologies continue to gain popularity at full scale wastewater treatment facilities. The limited studies which investigated fixed film wastewater treatment processes have reported that improved transformation efficiencies were observed relative to activated sludge systems. Based on these previous studies, it was postulated that the more diverse bacterial consortium present within the Integrated Fixed Film Activated Sludge (IFAS) process, a novel treatment process which has recently gained popularity in North America, may lead to improved transformation efficiencies (“removals”) of these very complex compounds. Only one previous study which investigated the transformation efficiencies of the IFAS process compared to a control was found. It was therefore considered that an additional investigation into the IFAS process warrants further investigation. Four IFAS Sequencing Batch Biofilm Reactors (SBBRs) and four control Sequencing Batch Reactors (SBRs) were operated with varied experimental conditions in a 22 factorial design to investigate whether an observable difference in the level of PC transformations would result via the IFAS process when compared to a control. Experimental conditions were characterized by varying the operating Solids Retention Time (SRT) and mixed liquor temperature. For all other operational parameters, best efforts were made to ensure both reactors were operated under equivalent conditions. This permitted a true assessment of the effects of the inclusion of IFAS media. Reactors were investigated through three phases of sampling, under which the performance of the reactors was investigated through the measurement of the following parameters: • Conventional parameters (tCOD, sCOD, TAN, NO3-N) within the initial and final samples; • Operational parameters (MLSS, MLVSS, ESS); and • The transformation efficiencies achieved for 5 PC (Carbamazepine, Sulfamethoxazole, Trimethoprim, Atenolol and Acetaminophen). During all three phases of PC sampling, the pilot reactors were found to have been performing as anticipated with respect to conventional contaminant removals. Organic removals were found to be statistically similar between the IFAS and control reactors across all four experimental conditions. Full nitrification was observed for all reactors with the exception of the control SBR operated under the low SRT, low temperature condition. The IFAS SBBRs were found to demonstrate improved nitrification kinetics when compared to their respective controls operated under the same experimental conditions. This was believed to be related to the more diverse bacterial consortia present as a result of the IFAS biofilms. All reactors were generally believed to be operating at steady state and were within an acceptable range of the target operating conditions. Due to complications associated with the analysis of samples, only CBZ, TRIM, ATEN and ACE could be successfully quantitated. CBZ was found to not have been transformed to any appreciable level across all conditions investigated through either the IFAS SBBRs or control SBRs. ACE was transformed at efficiencies greater than 99% under all conditions and in both IFAS and control reactors and therefore no comparison could be made. TRIM and ATEN demonstrated improved transformation efficiencies under all conditions within the IFAS reactors. The presence of IFAS media, SRT and temperature were all found to be statistically significant effects through ANOVA using a confidence limit of 95%.

Anaerobic digestion (AD) of corn thin stillage (CTS) offers the potential to reduce corn grain ethanol production energy consumption. This thesis focuses on results collected from AD of CTS at mesophilic temperatures in batch and by down-flow fixed film reactor. Experiments conducted include a series of biochemical methane potential (BMP) assays that investigated the digestion of CTS as the sole carbon source at a variety of food-to- microorganism ratios with and without acclimated biomass, under co-digestion conditions and also with the addition of supplemental nutrients. Additional BMP assays were conducted which investigated the potential to reduce fresh water consumption by using of digested effluent for substrate dilution. Continuous studies employed two 28L down-flow stationary fixed film reactors to examine. Chemical oxygen demand and volatile solids removal efficiencies greater than 85% were achieved up to an organic loading rate of 7.4 g TCOD/L/d and hydraulic retention time of 5 days.

Anaerobic digestion (AD) of corn thin stillage (CTS) offers the potential to reduce corn grain ethanol production energy consumption. This thesis focuses on results collected from AD of CTS at mesophilic temperatures in batch and by down-flow fixed film reactor. Experiments conducted include a series of biochemical methane potential (BMP) assays that investigated the digestion of CTS as the sole carbon source at a variety of food-to- microorganism ratios with and without acclimated biomass, under co-digestion conditions and also with the addition of supplemental nutrients. Additional BMP assays were conducted which investigated the potential to reduce fresh water consumption by using of digested effluent for substrate dilution. Continuous studies employed two 28L down-flow stationary fixed film reactors to examine. Chemical oxygen demand and volatile solids removal efficiencies greater than 85% were achieved up to an organic loading rate of 7.4 g TCOD/L/d and hydraulic retention time of 5 days.

No description available.

The performance of Biostyr media using an upflow biofilter scheme was investigated. Three separate Modes that varied the organic strength of the influent at an operating temperature of 12°C were evaluated to explore how nitrification and denitrification responded to different concentrations of biodegradable COD loadings. Effluent suspended solids and observed yield coefficients were also analyzed along with ways to determine kinetic parameters. Combinations of primary and secondary effluent were used as the influent using domestic wastewater from a primary sewer of the Blacksburg VPI Sanitation Authority, in Blacksburg, Virginia, located on the Virginia Tech Campus. Reduction of nitrification rates was observed in the aerobic reactor at biodegradable COD loadings to the aerobic biofilter of 2.2 kg/day/m³ and greater. Complete denitrification was observed in the anoxic tank at biodegradable COD loadings to the anoxic biofilter of 7.5 kg/day/m³ and greater. Above this value, denitrification was limited by the available amount of NOx-N. An optimum influent biodegradable COD loading rate of 7.5 kg/day/m³ to the anoxic biofilter and 2.2 kg/day/m³ to the aerobic biofilter was experimentally demonstrated for simultaneous nitrification and denitrification. When secondary effluent was fed to the reactors, complete nitrification was observed indicating success in terms of ammonia polishing. However, low concentrations of influent biodegradable COD limited the ability for the anoxic reactor to denitrify. Thus, it was determined that the addition of an external carbon source would need to be implemented to denitrify when using low strength secondary effluent. Effluent total suspended solids were consistently below 20 mg/L indicating that secondary clarification would not be needed for this reactor scheme. The combined observed yield was consistently around 0.2 (mg-VSS/mg-COD consumed) or less. However, the evaluation of separate anoxic and aerobic yields was inconsistent when averaging data over 5 days, because of the recycle of biomass from the aerobic reactor back to the anoxic reactor. The kinetic parameters, q'_{MAX NIT} and K’_{S NIT} were calculated by plotting nitrification rates as a function of ammonia concentration. These coefficients were calculated by using separate segments within the media under less than optimal conditions. It was determined that analyzing the whole system rather than segments would be better suited for kinetic parameter analysis. However, there was not enough collected data to achieve this. Thus, ranges identifying further influent biodegradable COD loadings were recommended for later research to better a complete kinetic parameter evaluation. / Master of Science

The performance of Integrated Fixed Film Activated Sludge (IFAS) was evaluated for its effect on nitrification and denitrification in a bench scale biological nutrient removal (BNR) process configured as a Virginia Initiative Project (VIP) process. The IFAS systems consisted of a sponge - like biomass support system (Captor) operated in the aerobic zone of two independent treatment trains, and a fibrous biomass support system (Ringlace) operated in the aerobic zone of one independent treatment train. A fourth treatment train containing no biomass support system was operated as a control. A range of four aerobic MCRTs was studied, from 3.4 days to 1.7 days. All experiments performed for this research effort were conducted using domestic wastewater obtained directly from Blacksburg, VA and the Virginia Tech campus. Results indicated that the presence of the sponge - like biomass support media (Captor) freely floating in the aerobic zone mixed liquor greatly increased the ability of that system to achieve nitrification at temperatures of 12 degrees Celsius and aerobic suspended growth MCRTs as low as 1.7 days. A statistical t-test analysis demonstrated this with 99% confidence. Results early in the research, as well as previous research by Mitta (1994) indicated that fibrous biomass support systems (Ringlace) did not perform as well with respect to nitrification as did Captor, and experiments on Ringlace were discontinued midway through the research. Increased denitrification throughout the IF AS/Captor train was noted as a result of the increased nitrification. However, the use of Ringlace appeared to enhance denitrification which occurred in the aerobic zone. Further study is recommended to verify this data. A decrease in sludge production in the IFAS train containing Captor could not be statistically established. However, observed sludge yield coefficients for the IF AS/Captor train were consistently lower than those for the Control train. A statistical analysis was not performed, but the values varied considerably so that direct comparison was difficult. / Master of Science