V. Dean Adams

Degradation of ethylene glycol in photo Fenton systems

Abstract Ethylene glycol loss rate constants of 1.0±0.40xa0h−1 were achieved in photo Fenton systems containing concentrations of 1000xa0mg/l ethylene glycol. Ethylene glycol was converted to formic acid resulting in a loss of calculated chemical oxygen demand. Iron was not catalytic in the system which may be due to the formation of ferric oxalate complexes. The system was inhibited by elevated concentrations of sulfate and a phosphate buffer solution. The optimal pH was 3.0, with significant decreases in the degradation rates below 2.8 and above 3.2. Increased TOC loss was noted in similar UV/H2O2 systems indicating a potential for increased mineralization in optimized photo Fenton systems with longer residence times.

Degradation of ethylene glycol using Fenton's reagent and UV.

Oxidation of ethylene glycol in aqueous solutions was found to occur with the addition of Fentons reagent with further conversion observed upon UV irradiation. The pH range studied was 2.5-9.0 with initial H2O2 concentrations ranging from 100 to 1000 mg/l. Application of this method to airport storm-water could potentially result in reduction of chemical oxygen demand by conversion of ethylene glycol to oxalic and formic acids. Although the amount of H2O2 added follows the amount of ethylene glycol degraded, smaller H2O2 doses were associated with increases in the ratio of ethylene glycol removed per unit H2O2 added indicating the potential of pulsed doses or constant H2O2 feed systems. Ethylene glycol removal was enhanced by exposure to UV light after treatment with Fentons reagent, with rates dependent on initial H2O2 concentration. In addition to ethylene glycol, the principle products of this reaction, oxalic and formic acids, have been shown to be mineralized in other HO generating systems presenting the potential for ethylene glycol mineralization in this system with increased HO* production.

Progress in the Development of Direct Osmotic Concentration Wastewater Recovery Process for Advanced Life Support Systems

Direct osmotic concentration (DOC) has been identified as a high potential technology for recycling of wastewater to drinking water in advanced life support (ALS) systems. As a result the DOC process has been selected for a NASA Rapid Technology Development Team (RTDT) effort. The existing prototype system has been developed to a Technology Readiness Level (TRL) 3. The current project focuses on advancing the development of this technology from TRL 3 to TRL 6 (appropriate for human rated testing). A new prototype of a DOC system is been designed and fabricated that addresses the deficiencies encountered during the testing of the original system and allowing the new prototype to achieve TRL 6. Background information is provided about the technologies investigated and their capabilities, results from preliminary tests, and the milestones plan and activities for the RTDT program intended to develop a second generation prototype of the DOC system.

Evaluation of methylene blue and riboflavin for the photosensitized degradation of ethylene glycol

Degradation rates ranging from 0.22 ± 0.11 to 1.52 ± 0.50 mg/L-h were measured for ethylene glycol in riboflavin solutions exposed to natural sunlight. Significant degradation rates were noted in systems using 6 and 10 mg/L riboflavin at pH values of 4, 7, and 10. No significant degradation was found in systems using methylene blue as the photosensitizing agent. Possible mechanisms for ethylene glycol degradation include a combination hydrogen or electron abstraction by an excited photosensitizer and reaction with singlet oxygen or reaction with superoxide radicals.

Engineering Methods for Europan Relevant Biosignature Development

One of the primary driving forces for space exploration in the foreseeable future is astrobiology, and specifically the search for a plausible sign of life beyond Earth. Because of the size of the potential saltwater ocean involved, Europa is potentially the most interesting, and possibly the only, currently viable (for life) environment in the solar system. It also presents the possibility of remote sensing evaluation for presence or absence of biotic and/or pre-biotic organic material. The material of interest is the non-ice (referring to water ice) surface material near features that have the potential of being in recent communication with the postulated ocean below. An analysis of this material using a full range of inorganic, pre-biotic organic, and metabolically relevant biologic materials as spectrum calibrating target materials, examined under Europan surface conditions, is a daunting proposition. A comprehensive attempt is still pending. This study involves the collection and growth of psychrophilic (low temperature), halophilic (high salt), anaerobic cultures in high sulfate environments. These cultures are intended as reflected spectrum target materials, based on relevant biomass, for comparison to Europan non-ice surface materials. The selection, collection, development (growth) and examination of this biotic material (blomass) requires the use of stringent, and in some cases extreme, environmental controls. It also requires the extrapolation of standard environmental engineering sampling and laboratory analysis procedures for use in comparison with, and interpretation of, data from a profoundly extreme and unfamiliar environment. The function of this study is to demonstrate the use of environmental engineering techniques and processes (test methodology) necessary to develope a reasonable biosignature related to the Europan target environment.

Sulfur Dioxide Treatment of Secondary sewage: Effect on Viruses

Abstract Many resources and much effort has been devoted to viral inactivation studies due to potential serious health implications associated with viral contamination. Sulfur dioxide has been evaluated to determine its potential to inactivate reovirus and poliovirus. Reovirus (PIV or IV) in wastewater was inactivated with SO 2 treatment by 90%. Poliovirus in wastewater was ionactivated by 97% with a 500 mg/L SO 2 treatment.