Engineering Treatment of Hazardous Wastewaters Utilizing Dye-sensitized Photooxidation

Studies were conducted to determine the applicability of photooxidation for the degradation of selected hazardous and refractory organic compounds. These photochemical oxidation reactions occur through the transfer of energy from electronically excited sensitizer molecules which attain excited states by absorbing visible light energy. Optimum conditions for photooxidation were established based on sensitizer concentration and reaction pH for four polynuclear aromatic pollutants. The rate of photooxidation was found to be independent of the initial substrate concentration for methylene blue-sensitized reactions, and dependent on substrate concentration for solutions without a sensitizing dye. Photolysis of substrate mixtures established acridine and anthracene as photochemically active substrates. Photochemical reaction data suggest predictable trends in substrate reactivity based on pKa values of both sensitizer and substrate, initial substrate concentration and light absorbance characteristics. The photoproducts formed during the photolysis of acridine were found to be more toxic than the parent compound. These reaction products appear to be atable and warrant further study

Reverse Osmosis in the Treatment of Drinking Water

An extensive review of the literature was conducted and results were evaluated for the use of the reverse osmosis process in the treatment of drinking water supplies. All aspects of reverse osmosis technology, including pretreatment requirements; membrane type and configuration; membrane cleaning and maintenance; and reverse osmosis removal of organics, inorganics, and microbial contaminants were incorporated inot the literature evaluation. A survey (Appendix E) of existing full scale reverse osmosis installations was also carried out and results of the survey are discussed. In light of data presented in the literature and results of the survey conducted, the following recommendations were made to prevent catastrophic membrane fouling occurrences and costly plant shutdowns in the future. 1) Conduct a comprehensive raw water quality evaluation. 2) Maintain continuous feed and product water quality monitoring. 3) Incororate process automation and system upset warning provisions in future installations. 4) Provide greatly improved training for reverse osmosis installation operators. The reverse osmosis system is particularly well suited for the treatment of water supplies which contain a number of contaminants that would otherwise require a combination of treatment processes for their removal, due to the ability of the reverse osmosis process to remove salts, organics, and a number of microbial contaminants. Effective pretreatment and routine backwashing, membrane cleaning, and disinfection must be carried out; however, if adequate system operation is to be assured

Soil Phase Photodegradation of Toxic Organics at Contaminated Disposal Sites for Soil Renovation and Groundwater Quality Protection

Accurate assessment of the potential for contaminated soil remediation requires detailed knowledge of the fate of waste constituents within the soil environment. For many non-biodegradable organics compounds, photochemical degradation may provide a potential pathway for the removal of such compounds from soil surfaces. A study was conducted to evaluate the rate of photodegradation of ten hazardous organic compounds from three soils, silica gel, and four soil minerals (kaolinite, montmorillonite, illite, and calcite) under conditions of controlled irradiation. In addition, the effect of siz amendment treatments (methylene blue, riboflavin, hydrogen peroxide, diethylamine, peat moss, and silica gel) on the rates of compound loss was also investigated. Soil and mineral samples were spiked with various combinations of m-cresol, quinoline, biphenyl, dibenzo[a]furan, fluorene, pentachlorophenol, phenanthrene, anthracene, 9H-carbazole and pyrene at either 500 or 1000 mg/kg initial soil concentration of each chemical. Amendments were applied to the soils and minerals and duplicate samples were irradiated in petri dishes under ultraviolet or visible light while spike controls were inclubated in the dark. Linear regression of soil/mineral contaminant concentration data showed that first order kinetic modeling best described the degradation process. Significant loss of anthracene occurred on all surfaces tested althrough the rate of loss varied with surface type and, for some surfaces, with the spiking solution concentration and chemical mixtures. Anthracene loss from silica gel was the msot rapid of all reactions observed. Skumpah soil, a light colored alkaline soil, yielded the greatest reduction in contaminant concentrations found in the soil studies. Calcium kaolinite displaed the most rapid kinetics of the mineral surfaces tested. Loss of the other test compounds was observed from only some of the surfaces investigated. Anthraquinone and fluorenone were identified as the major degradation products of the photoreaction of anthracene and fluorene. Under the conditions of this study, soild and mineral type, as well as surface renewal via mixing, were found to have more effect on degradation rates than any of the amendments that were tested

Toxicity and Environmental Health Hazards of Petroleum Products in Wells Used for Drinking Water in the Intermountain West

Introduction: Groundwater is aprimary source of drinking water for about 50 percent of the population in the U.S. This source of drinking water has been generally regarded as safe from contamination. Several papers indicate that numerous underground storage tanks containing petroleum products may be leaking and contaminating public water supply wells across the U.S. (Matis, 1971; Ferguson, 1979; Woodhull, 1981; Burmaster and Harris, 1982; Lehman, 1984; Dowd, 1984; OTA, 1984). A study conducted by the Utah Cureau of Solid and Hazardous Wastes in 1985 concluded that there are at least 2,314 underground steel tanks, most of which are used to store gasoline and diesel fuel, in Utah which are more than 20 years old and may be leaking. Contamination of well water by petrolium products from leaking underground storage tanks (LUST) is a matter of increasing concern. LUST pose a serious threat to the groundwater and public health. Leaks of petroleum products from LUST at industrial plants, commercial establishments (e.g., automobile service stations), and other operations could be expected to increase the types and concentrations of petroleum products in groundwater used for drinking and exposure of humans to the toxic effects of these chemical compounds. Petroleum products are persistent and highly mobile contaminatns which are difficult to remove from groundwater. In addition, many of these chemicals are known or suspected carcinogens or mutagens which can pose undesireable human health risks (e.g., cancer, birth defects, and other chronic conditions) at 10 ppb and below (Council on Environmental Quality, 1980). There is a need for more research on the types and concentrations of petroleum products (e.g., benzene, toluene, ethylbenzene) found in public water supply wells used for drinking water and the immunotoxic and neurotoxic effects of these organic compounds. The objectives of this research project were: 1. To characterize petroleum products in raw water from wells used for drinking water in selected areas (industrial, commercial, and other) of Utah. 2. To evaluate the toxicity of selected petroleum products in experimental animals, with emphasis on the following: a. Immunotoxic and hypersensitivity effects. b. Neurotoxic and behavioral effects

Evaluation of Volatilization of Hazardous Constituents at Hazardous Waste Land Treatment Sites

The magnitude and extent of volatile organic emissions from hazardous waste land treatment systems were evaluated in laboratory and field studies using complex petroleum refining hazardous wastes. Laboratory experiments were conducted using two soils and a intert construction sand to investigate the emission flux rates of seven volatile constituents, i.e., benzene, toluene, ethylbenzene, p-, m-, o-xylene, and naphthalene, from API Separatory Sludge and Slop Oil Emulsion Solids wastes in column and flask laboratory units as a function of waste application rate, application method (surface versus subsurface), soil type and soil physical characteristics. Field experiemtns were conducted at an active petroleum refinery hazardous waste land treatment site to which a combined API Separator Sludge/DAF bottom sludge was surface applied. The emission rates of the sevel pure volatile constituents evaluated in the laboratory studies were quantified in the field study. Pure constituent collection and quantification in both laboratory and field studies were carried out using a surface isolation emission flux chamber and a split stream Tenax sorbent tube concentration system. Laboratory and field sampling train evaluation indicated that the system is best quited for high emission rate measurements, i.e., just following waste application, and requires diligent QA/QC procedures to minimize background contamination and to assure representativeness of measured data. Suggested operating procedures in terms of purge flow rates, split stream sampling rates, sample collection volumes for minimal contaminant sorbent tube breakthrough, etc., are presented. Measured laboratory and field data were comapred to the Thibodeaux-Hwang Air Emission Release Rate (AERR) model in an effort to validata this state-of-the-art land treatment air emission model. Data generally confirm the validity of the diffusion based on modeling approach for land treatment air emissions, especially for emission rates immediately following sruface waste application. Both field and laboratory surface application measured data correlated with Thibodeaux-Hwang AERR model predictions within a factor of two to ten. Laboratory subsurface application experiments were within one to two orders of magnitude of predicted values. The dynamics of the geometry of the subsurface contaminated zone following subsurface application, along with the hypothesis of concentration gradient development in the soil zone above the application plane, indicate that the simple diffusion based model does not adequately describe the unsteady-state diffusion process occurring following subsurface application events. The variability observed in point waste loading, and soil physical and temperature conditions observed during the field study suggest that detailed waste loading data (using a pan method described in the report) and site and time specific soil data are required for accurate correlations between measured and predicted waste constituent emission flux rates. Once specific data are collected which describe the physical environment of the land treatment system, the accurate prediction of pure constituent air emissions from surface application and tilling can be provided by the Thibodeaux-Hwang AERR model even for complex hazardous wastes applied to complex soil systems. This report was submitted in partial fulfillment of Cooperative Agreement CR-810999-01-0 by the Utah Water Research Laboratory, Utah State University under the partial sponsorship of the U.S. Environmental Protection Agency. This report covers a period from August 1983 to january 1986, and the work was completed as of July 1986

Treatability Study of Car Wash Wastewater Using Upgraded Physical Technique with Sustainable Flocculant

Grease, oil, hydrocarbon residues, heavy metals, and surfactants are all present in car wash wastewater (CWW), which all can have detrimental effects on the environment and human health. This study was designed to assess CWW treatment using an upgraded physical technique combined with a range of conventional and more sustainable coagulants. Physical treatment effectively lowered the oil and grease (O&G) and chemical oxygen demand (COD) of the CWW by 79 ± 15% and 97 ± 1.6%, respectively. Additional treatment was provided using chemical coagulation–flocculation– settling. In jar test studies, humic acid (HA) and alum were found to provide significantly higher turbidity removal, 79.2 ± 3.1% and 69.8 ± 8.0%, respectively, than anionic polyacrylamide (APA), 7.9 ± 5.6% under influent turbidity values from 89 to 1000 NTU. Overall physical/chemical treatment of CWW yielded 97.3 ± 0.8% COD removal, and 99.2 ± 0.4% O&G removal using HA and alum. Due to the numerous problems created when using synthetic coagulants, naturally occurring coagulants that have no impact on human health, such as HA, are highly desirable options. The findings of this study show that treating CWW provides several advantages for sustainable development, health and well-being, and raising public knowledge and support for water reuse

Review of In-Place Treatment Techniques for Contaminated Surface Soils - Volume 2: Background Information for In Situ Treatment

This second volume of a two volume manual on in-place treatment of hazardous waste contaminated soil supports the treatment methodology described in Volume 1 (EPA- ). The information presented on monitoring to determine treatment effectiveness, characterization and evaluation of the behavior and fate of hazardous constituents in soil/waste systems, and properties (including adsorption, degradation, and volatilization parameters) for various compounds is intended to help the manual user in making more complex decisions and in selecting analyses concerning site, soil, and waste interactions. This report was submitted in partial fulfillment of Contract No. 68-03-3113 by Utah State University under the sponsorship of the U.S. Environmental Protection Agency. The report covers the period December 1982 to December 1984 and work was completed as of January 1984

Measurement of 73 Ge(n,γ) cross sections and implications for stellar nucleosynthesis

© 2019 The Author(s). Published by Elsevier B.V.73 Ge(n,γ) cross sections were measured at the neutron time-of-flight facility n_TOF at CERN up to neutron energies of 300 keV, providing for the first time experimental data above 8 keV. Results indicate that the stellar cross section at kT=30 keV is 1.5 to 1.7 times higher than most theoretical predictions. The new cross sections result in a substantial decrease of 73 Ge produced in stars, which would explain the low isotopic abundance of 73 Ge in the solar system.Peer reviewe

Measurement of the Ge 70 (n,γ) cross section up to 300 keV at the CERN n-TOF facility

©2019 American Physical Society.Neutron capture data on intermediate mass nuclei are of key importance to nucleosynthesis in the weak component of the slow neutron capture processes, which occurs in massive stars. The (n,γ) cross section on Ge70, which is mainly produced in the s process, was measured at the neutron time-of-flight facility n-TOF at CERN. Resonance capture kernels were determined up to 40 keV neutron energy and average cross sections up to 300 keV. Stellar cross sections were calculated from kT=5 keV to kT=100 keV and are in very good agreement with a previous measurement by Walter and Beer (1985) and recent evaluations. Average cross sections are in agreement with Walter and Beer (1985) over most of the neutron energy range covered, while they are systematically smaller for neutron energies above 150 keV. We have calculated isotopic abundances produced in s-process environments in a 25 solar mass star for two initial metallicities (below solar and close to solar). While the low metallicity model reproduces best the solar system germanium isotopic abundances, the close to solar model shows a good global match to solar system abundances in the range of mass numbers A=60-80.Peer reviewedFinal Published versio