Download or read book Kinetics of Anaerobic Degradation of Glycol based Aircraft Deicing Fluids written by Theodore H. Schoenberg and published by . This book was released on 2000 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Degradation of Glycol Based Aircraft Deicing Fluids Under Anaerobic Methanogenic Conditions written by Shawn H. Veltman and published by . This book was released on 2000 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Anaerobic Degradation of Aircraft Deicing Fluid ADF in Upflow Anaerobic Sludge Blanket UASB Reactors and the Fate of ADF Additives written by Thi Tham Pham and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions were conducted in continuous mode. The development of four empirical models describing process responses (i.e., chemical oxygen demand (COD) removal efficiency, biomass specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time (HRT), and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass specific acetoclastic activity was improved by almost two-fold during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. Predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate (OLR) was increased. ADF toxicity effects were evident for 1.6% ADF at medium specific organic loadings (SOLR above 0.5 g COD/g VSS/d). In contrast, good reactor stability and excellent removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73 g COD/g VSS/d). Acclimation to ADF resulted in an initial reduction in the biomass settling velocity. The fate of ADF additives was also investigated. There was minimal sorption of benzotriazole (BT), 5-methyl-1 H-benzotriazole (MeBT), and 5,6-dimethyl-1 H-benzotriazole (DiMeBT) to anaerobic granules. A higher sorption capacity was measured for NP. Active transport may be one of the mechanisms for NP sorption. Ethylene glycol degradation experiments indicated that BT, MeBT, DiMeBT, and the nonionic surfactant Tergitol NP-4 had no significant effects on acidogenesis and methanogenesis at the concentration levels studied. A significant inhibition of acetoclastic activity was observed for NP at 100 mg/L, with acetic acid consumption rate at 38% of that for controls. No evidence for anaerobic degradation of benzotriazole and its derivatives was observed; however, both batch and continuous experiments suggested that anaerobic degradation of NP occurred. Kinetic analysis of operational data obtained for the anaerobic treatment of ADF in UASB reactors indicated that the substrate utilization rate was independent of the reactor biomass concentration. The maximum rate of substrate utilization and the half-velocity constants for ADF treatment were 28.4 g COD/L/d and 648 mg COD/L, respectively. For 1.2% ADF, the biomass yield and endogenous decay coefficients were 0.027 g VSS/g COD and 0.012 d-1 , respectively.
Download or read book Draft Toxicological Profile for Ethylene Glycol written by and published by . This book was released on 2007 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1999 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index Medicus written by and published by . This book was released on 2003 with total page 1538 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
Download or read book Preliminary data summary airport deicing operations written by and published by DIANE Publishing. This book was released on 2000 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Efficient On site Degradation of High Concentration of Spent Deicing Fluids written by and published by . This book was released on 1997 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The on-site treatment of antifreeze compounds and aircraft deicing fluids (ethylene glycol and propylene glycol) will reduce disposal costs, decrease environmental impact, minimize the potential for additional spills/contamination and meet the goals of pollution prevention by reducing the amount of hazardous materials generated. The authors have identified bacteria that can degrade 1-10% glycol waste at room temperatures of ca. 23C. A second subculture was isolated that could degrade glycol waste at ca. 4C.
Download or read book DEICING FLUID AIRCRAFT Ethylene Glycol Base written by G-12ADF Aircraft Deicing Fluids and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design of Aircraft Deicing Facilities written by and published by . This book was released on 1993 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aircraft De icing anti icing Fluid ADAF laden Wastewater written by Sandra L. Smith-Cunningham and published by . This book was released on 2008 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: ?Pub Inc Airports that operate in cold climates are required by the FAA to de-ice aircraft and runways. The most common method involves the use of glycol-based aircraft de-icing/anti-icing fluids (ADAF). The majority of these fluids contain either propylene or ethylene glycol that act as freezing point depressants, along with additives such as corrosion control inhibitors, surfactants, and wetting agents. Historically, the runoff of spent fluids from aircraft and pavement de-icing/anti-icing operations has been difficult to manage, resulting in significant discharges to surface waters on both a national and global level. Currently, best-practice treatment of airport storm water containing ADAF is geared for glycol-rich wastewaters, with the treatment efficiency being measured by reduction of BOD and nutrient levels in the effluent. The objective of the thesis was to assess whether the traditional parameters (BOD, COD, and pH) most frequently used to monitor the treatment and release of airport stormwater effluent containing de-icing fluids were adequate indicators of the effluent quality. Current literature was used to evaluate the chemistry, environmental fates, persistence in the environment, and toxicity of two classes of compounds, glycols and benzotriazoles. Glycols were shown to be readily degraded in the environment and relatively non-toxic. Benzotriazoles were shown to be resistant to degradation, persistent, and toxic in the environment. The fate of both of these types of compounds was then evaluated in best practice treatment methods for airport stormwater. Glycols were shown to be effectively treated and benzotriazoles were projected to be recalcitrant. The research supports the hypothesis that using BOD, COD, and pH as measures of suitability of return to the environment for treated stormwater containing spent ADAF is inadequate. New additives and more sophisticated ADAFs affect the toxicity of the effluent and require treatment processes that effectively treat all of the constituents of the fluid.
Download or read book Fate and Toxicity of Aircraft Deicing Fluid Additives Through Anaerobic Digestion written by Cynthia Lee Gruden and published by . This book was released on 2000 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book DEICING ANTI ICING FLUID AIRCRAFT Ethylene Glycol Base written by G-12ADF Aircraft Deicing Fluids and published by . This book was released on 1981 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This specification covers an ethylene-glycol base deicing/anti-icing fluid in the form of a concentrated liquid.
Download or read book DEICING ANTI ICING FLUID AIRCRAFT Propylene Glycol Base written by G-12ADF Aircraft Deicing Fluids and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This specification covers a deicing/anti-icing material in the form of a fluid.
Download or read book Anaerobic Co digestion and Phasing for Aircraft De icing Fluid Treatment written by Kathleen Mary McGrady and published by . This book was released on 1999 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determining Employee Exposure to Ethylene Glycol While Performing Maintenance on an Aircraft Deicing Fluid Collection System written by and published by . This book was released on 2007 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Air monitoring was performed on an aircraft deicing fluid collection system at the Cincinnati/Northern Kentucky International Airport (CNKIA). The goal of the study was to determine employee exposure to ethylene glycol and the target compounds of decomposition as maintenance was performed on the system. The maintenance work involved performing confined space entries to repair and maintain various diversion chambers, pump stations and storage tanks used to collect and convey spent aircraft deicing fluid. The collected deicing fluid during the period of the study was primarily ethylene glycol based. The study included low flow area air sampling of selected diversion valve pits, pump stations and storage tanks for the presence of ethylene glycol as well as ethanol, formaldehyde, and acetaldehyde which are suspected end products of decomposition of ethylene glycol. The study also included the collection of weekly samples using Draeger Tubes to test for ethylene glycol. Samples were collected in the spring, summer and winter months. The results of the study revealed that the target compounds of decomposition were detected in various concentrations throughout the sample study. All results for the decomposition compounds were well below established regulatory and recommended levels. The weekly analysis for ethylene glycol revealed the potential for exposure to ethylene glycol at the diversion valves and to a lesser extent at the deicing pad pump stations during periods of heavy deicing. Ceiling limits for ethylene glycol at deicing fluid collection valves appear to be exceeded during periods of deicing fluid use greater than 750 gallons per day.
Download or read book Treatment of Dilute Aircraft Deicing Fluid ADF Using an Anaerobic Baffled Reactor ABR written by Juan Marín Hernández and published by . This book was released on 2005 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
