Catalytic Oxidation of Sulfur Dioxide in Wastewater

Sulfur dioxide has been shown to be an effective wastewater disinfectant. The aqueous sulfur dioxide creates and oxygen demand in the effulent which must be removed prior to discharge. Oxidation to sulfate is one means of accomplishing this task. Experiments were carried out to determine the effectiveness of transition metals and activated carbon as catalysts for the oxidation of S+IV species in wastewater. Both the metals and carbon are known catalysis, but what inhibitory effect the wastewater might have was unknown. Effectiveness was defined as a combination of catalyst life, effluent quality, and cost. Tradition metals were eliminated as potential catalysts due to the high metal concentrations found in the effluent. The acidic nature of 500 mg/l SO2 dissolved in wastewater (pH 2.5) would dissolve the metals or cause them to desorb from a carbon base. Using downflow contractors, activated carbon was shown to catalyze the reaction as long as sufficient oxygen was available. At a loading rate of 5.5 h carbon/1 and a hydraulic loading of 38 M^3/M^2 * day, 24 hour runs were accomplished without SO2 breakthrough (less than 4 mg/1). Longer runs resulted in gradual breakthrough (40 mg SO2/1 after 96 hours). The cause of the failure was assumed to be the self-poisoning of the catalyst by sulfuric acid (the product of SO2 oxidation) and/or the reduced solubility of oxygen in the sulfuric acid solution. Carbon regeneration, as a catalyst, was accomplished by backwashing the column with tap water. The cost of sulfur dioxide disinfection ranged from $0.23 -$0.73/1000 gallons treated. In general, this process was much more costly than other disinfection systems

A Study of Trihalomethane Precursors in Deer Creek Reservoir

Deer Creek Reservoir and tributaries were monitored from May to December 1983 in a study of the occurrence of trihalomethane (THM) precursors in the reservoir and nutrient dynamics of the reservoir system. Microcosms were used to study the effect of the following parameters on THM precursor production in the reservoir system: phosphorus loading, sediment, algal growth, and application of algicide. Additionally, THM precursor concentrations of interstitial water were analyzed in reservoir and microcosm sediment samples. Microcosms treated with ahigh phosphorus loading (70 ug/1) had THM precursor concentrations significantly higher than those measured in microcosms treated with a low phosphorus loading (10 ug/1). The presence of sediment in microcosms did not significantly affect THM precursor concentrations. Algae growth did result in THM production significantly aboce that measured in microcosms without algae growth. No correlation between total organic carbon and terminal total trihalomethane concentrations was found to exist in microcosms. Potassium permanganate and copper sulface were used as algicides. Applications of 0.3 mg/1 potassium permanganate and 50 ug/1 copper sulfate as Cu^+2 did not appear to affect THM precursor, total phosphorus, total suspended solids, or volatile suspended solids concentrations in the microcosms. Anoxic phosphorus release occurred in dark microcosms after the dissolved oxygen concentration dropped below approximately 3.0 mg/1. Considering all data collected, no significant difference in THM precursor concentraion could be detected between tributary and reservoir samples. THM precursor concentrations in tributaries were found to vary significantly be season. Samples collected from three depths within the reservoir were not found to have significantly different mean terminal total trihalomethane concentrations over the sampling period. No correlation between total organic carbon and terminal total trihalomethane concentrations was found to exist. Total phosphorus concentrations in tributaries were quite high, particularly in Main and Daniels Creeks

"Talk to Them": Teaching communication skills to students of traditional chinese medicine.

Objective: To explore students’ perceptions of the efficacy and value of teaching communication skills in a health professional course for Traditional Chinese Medicine (TCM). Methods: Individual surveys were used to evaluate students’ self-assessment of their communication skills pre and post a communication subject in a four-year degree course in a Bachelor of Health Science in TCM at a large metropolitan university in Australia. Quantitative and qualitative data were collected. Results: Findings indicate that students recognise the need for good communication skills training as part of their professional training and self-reported that their communication skills improved following a semester of study of a communication subject. Conclusions: One of the primary components driving increasing demand for complementary and alternative medicine (CAM), which includes TCM, is that consumers place a high value on effective communication and quality engagement with their CAM provider. Communication skills are often seen as the cornerstone of good health care practice, patient recovery and practitioner job satisfaction. Implementing a focused communication skills component in health professional educational programs, including those for TCM, is therefore essential. Further research is needed to explore the retention of these skills throughout health professionals’ degree programs and after graduation and clinical experience, to evaluate the effectiveness and sustainability of personal communication skills education. Practice implications: Communication skills training should be incorporated into health care profession curricula, early in the program and integrated with clinical exposure

Development of Design Criteria for Sensitizer Photooxidation Treatment Systems

Sensitized photooxidation is a physicochemical process that can degrade many toxic and refractory organic pollutants. A trace quantity of sensitizer added to the waste absorbs visible light; electronically excited intermediates then transfer the energy to decompose the waste. Engeineering design criteria were developed for industrial waste treatment lagoons that would use sensitized photooxidation. Design criteria were developed regarding optimum lagoon pH, optimum sensitizer concentration, depth and sizing of lagoons, dissolved oxygen requirements, and effect of temperature on photooxidation rate. Treatment of the refractory pesticides bromacil, terbacil, and fluometuron was investigated using methylene blue and riboflavin as sensitizers. Methylene blue-sensitized photooxidation of the three pesticides was most efficient at basic pH. The optimum pH of riboflavin-sensitized photooxidaction varied and was substrate-dependent. A model was developed to predict sensitized photooxidation rate as a function of lagoon depth. The model is based on light intesnity, sensitizer extinction coefficient, and an applied quantum yeirld, all of which are integrated over wavelengths of visible light. The model serves as the basis of sizing photooxidation lagoons. A dissolved oxygen residual of 1 mg/1 was required to maintain maximum methylene blue-sensitized photooxidation rate. At least 4 mg/1 dissolved oxygen was necessary to maintain riboflavin-sensitized phooxidation at maximum levels. Oxygen uptake rates in sensitized phooxidation reactions were proportional to the concentration of substrate. Temperatures from 10 degrees to 35 degreees Celcius had no significant effect on sensitized photooxidation rates. Using the model developed, a methylene blue-sensitized phooxidation pilot lagoon was designed to treat a 30 mg/1 bromacil influent concentraion to 0.1 mg/1 bromacil in the effluent. For an influent flow of 0.263 m^3/min (0.1 MGD) waste, a 0.1 mg/1 methylene blue concentration, 36 cm depth, and 1870 m^2 surface area are required. A cost analysis was performed which indicated that sensitized photooxidation lagoons appear to be cost-compentitive with other industrial waste treatement systems

A Laboratory Evaluation of Leachate from the Jim Bridger Power Plant Scrubber Wastes

Introduction: Scrubber wastes obtained in an affort to limit air pollution generated by coal-fired pwoer plants may contribute to another possible sources of pollution. To date, scrubber wastse have been in a liquid phase which causes disposal problems partially due to the liquid characteristics. The use of solid scrubber wastes and the land deposition of such wastes is proposed. The feasibility of solid scrubber wastes disposal in landfills is under question. The primary area of concern is the effect that water percolation through such wastes would have on groundwater quality parameters. Contamination could result either as precipitation travels downward through the wastes and into the water table or as the water table rises into the scrubber wastes and then retreats. Groundwater contamination is a key concern because it is largely irreversible and has long term consequences. Objective: Disposal methods for coal-fired power plant fly ask and scrubber wastes present a potential for the contamination of groundwater aquifers. In this study the general objective was to evaluate the physical and chemical characteristics of the leachates of scrubber weastes and associated disposal materials separately and in appropriate combinations using laboratory bench scale techniques. Two appraoches, namely column leaching and batch elutriation, were developed and used to provide indicators characterisitic of the materials tested

Natural Salinity Removal Processes in Reservoirs

A small but significant amount of salinity removal has been reported by various authors to occur in mainstem Colorado River reservoirs. Recalculation of some of these salinity budgets, together with a review of the data bases used, usggests taht removal has not often been conclusively demonstrated. Laboratory microcosm experiments and field data indicate that calcium carbonate precipitation, perhaps with some coprecipitation of magnesium carbonate, is the mechanism responsible for most of the salinity removal in Oneida Reservoir, Idaho. Coprecipitation processes (including ion exchange), coagulation, and bioassimilation do not appear to be important natural salinity removal mechanisms. Finally, loss of calcium, relative to monovalent cations, may decrease water quality for irrigation purposes through increasing the sodium adsorption ratio (SAR), despite a pross decrease in the TDS. The potential role of various reservoir operation options in managing natural salinity removal processes and the value of such removal is discussed

Heterogeneity of diabetes outcomes among asians and pacific islanders in the US: the diabetes study of northern california (DISTANCE).

ObjectiveEthnic minorities with diabetes typically have lower rates of cardiovascular outcomes and higher rates of end-stage renal disease (ESRD) compared with whites. Diabetes outcomes among Asian and Pacific Islander subgroups have not been disaggregated.Research design and methodsWe performed a prospective cohort study (1996-2006) of patients enrolled in the Kaiser Permanente Northern California Diabetes Registry. There were 64,211 diabetic patients, including whites (n = 40,286), blacks (n = 8,668), Latinos (n = 7,763), Filipinos (n = 3,572), Chinese (n = 1,823), Japanese (n = 951), Pacific Islanders (n = 593), and South Asians (n = 555), enrolled in the registry. We calculated incidence rates (means ± SD; 7.2 ± 3.3 years follow-up) and created Cox proportional hazards models adjusted for age, educational attainment, English proficiency, neighborhood deprivation, BMI, smoking, alcohol use, exercise, medication adherence, type and duration of diabetes, HbA(1c), hypertension, estimated glomerular filtration rate, albuminuria, and LDL cholesterol. Incidence of myocardial infarction (MI), congestive heart failure, stroke, ESRD, and lower-extremity amputation (LEA) were age and sex adjusted.ResultsPacific Islander women had the highest incidence of MI, whereas other ethnicities had significantly lower rates of MI than whites. Most nonwhite groups had higher rates of ESRD than whites. Asians had ~60% lower incidence of LEA compared with whites, African Americans, or Pacific Islanders. Incidence rates in Chinese, Japanese, and Filipinos were similar for most complications. For the three macrovascular complications, Pacific Islanders and South Asians had rates similar to whites.ConclusionsIncidence of complications varied dramatically among the Asian subgroups and highlights the value of a more nuanced ethnic stratification for public health surveillance and etiologic research

Use of Saline Water in Energy Development

Maps were made of the Upper Colorado River Basin showing locations of coal deposits, oil and gas, oil shale, uranium, and tar sand, in relationship to cities and towns in the area. Superimposed on these are locations of wells showing four ranges of water quality; 1,000-3,000 mg/l, 3,000-10,000 mg/l, 10,000-35,000 mg/l, and over 35,000 mg/l. Information was assembled relative to future energy-related projects in the upper basin, and estimates were made of their anticipated water needs. Using computer models, various options were tested for using saline water for coal-fired power plant cooling. Both cooling towers and brine evaporation ponds were included. information is presented of several proven water treatment technologies, and comparisons are made of their cost effectiveness when placed in various combinations in the power plant makeup and blowdown water systems. A relative value scale was developed which compares graphically the relative values of water of different salinities based on three different water treatment options and predetermined upper limits of cooling tower circulating salinities. Coal from several different mines was slurried in waters of different salinities. Samples were analyzed in the laboratory to determine which constituents had been leached from or absorbed by the coal, and what possible deleterious effects this might have on the burning properties of the coal, or on the water for culinary use or irrigation

Evaluation of the Potential for Groundwater Transport of Mutagenic Compounds Released by Spent Oil Shale

The major focus of this study was on the potential mutagenicity of aqueous leachates from spent oil shale. Additional mutagenicity testing was also done on raw shale and coal. The Ames salmonella microsomal bioassay was used to test for chemical mutagenicity. Spent oil sahles from the Paraho and TOSCO II processes, a raw shale from Anvil Points, and a composite coal sample from the Wasatch plateau were extracted with water and organic solvents. Only organic solvent extraction of the TOSCO spent shale resulted in a mutagenic response. The lack of mutgenic reponse to organic extracts of Paraho spent shale was unexpected and was probably due to higher than typical temperatures at which it had been retorted. Using TOSCO spent shale leachate and the organically extracted mutagen, a partition relationship between the spent shale and leachate water was developed. The mutagen was found to have a fairly high affinity for spent shale. Based on this it was estimated that mutagenicity of the TOSCO spent shale leachate will be low (in the range of chlorinated wastewater), however it will require many pore volumes to leach out of a pile potentially resulting in a chronic long-term problem