Ozone

The Kyoto protocol establishes a gradual reduction of gas emissions to control the greenhouse effect and the destruction of the ozone layer. The conventional refrigeration systems are based on the cyclic compression and expansion of some fluid with the subsequent gas-liquid transitions. The heat transferred from the cool source to the hot one is basically the latent heat of vaporization. The typical fluids used for this purpose are highly contaminant in the sense of the Kyoto protocol. They are confined to closed circuits, but sooner or later they leak to the atmosphere. Therefore some alternatives are being searched. One of the most promising methods is based on the

Air quality indices currently in use have been criticized because they do not capture additive effects of multiple pollutants, or reflect the apparent no-threshold concentration-response relationship between air pollution and health. We propose a new air quality health index (AQHI), constructed as the sum of excess mortality risk associated with individual pollutants from a time-series analysis of air pollution and

The efficiency of ozone as a pre- and post-treatment to UASB treatment was investigated, followed by a study into UASB reactor performance with ozonated wastewater as substrate. Combinations of pre- and/or post-ozonation with UASB treatment gave better results than ozonation or UASB alone and COD reductions of 53.0-98.9% were achieved for treatment of canning and winery wastewaters. A UASB reactor was fed with pre-ozonated cannery wastewater for over 70 d. COD removal improved from between 58.8 and 64.4% to between 85.3 and 91.8% after pre-ozonated substrate feed commenced. Subsequent increases in organic loading rate (OLR) from 2.4 to 3.4 kgCOD m(-3) x d(-1) did not affect reactor performance. By including a final post-ozonation treatment to this UASB effluent a total COD reduction of 99.2% was achieved.

Multi-resistant drug bacteria are an emerging health care concern around the world. A decreased resistance to infection as seen in Chronic Kidney Disease (CKD) and kidney transplanted patients as well as some metabolic abnormalities such as hyperglycemia and glycosuria or clinical conditions such as the neurogenic bladder may indeed portend a great risk of recurrent urinary tract infections (UTI). The common and indiscriminate use of antibiotics often provides the patients with only a transient or partial amelioration of the urinary tract discomforts and increases the risk of multi-resistant drug bacteria selection. Thus a great effort is made in order to develop new antibacterial approaches especially in the setting of multi- antibiotic resistant pathogens. We herein report on some promising yet preliminary results of the use of ozone therapy in UTI.

The chemistry and energetics of the Criegee intermediate, a primary product of the ozonolysis of alkenes, are discussed in terms of recent ab-initio calculations and laboratory studies. The experimental observations in O3–alkene systems can be rationalized on the basis of a general mechanism: where the ‡ represents the range of internal excitation energies available to the planar dioxymethylenes (i.e., the Criegee intermediates) initially formed via exothermic O3-alkene reactions. Estimates are given for the rate constants of these reactions, and a critique is provided of the possible role of the Criegee intermediate and its isomers in the formation of alkanoic acid anhydrides in O3–alkene systems and in the formation of H2SO4 aerosols in O3–alkene–SO2 systems.

Tomato juice samples were ozonated with control variables of ozone concentration (1.6–7.8 %w/w) and treatment time (0–10 min). Effects of ozone processing variables on quality parameters of pH, oBrix, titratable acidity (TA), cloud value, non-enzymatic browning, colour values (L*, a*, and b*) and ascorbic acid (AA) content were determined. No significant changes (P > 0.05) in pH, oBrix, TA, cloud value and Non enzymatic browning (NEB) (P ≤ 0.05) were found with ozonation. L*, a* and b* colour values were significantly affected by ozone concentration and treatment time. A significant reduction of AA (96 %) was observed at an ozone concentration of 7.8%w/w and a treatment time of 10 min. Results presented in this study indicate that visual colour and nutritional quality is significantly affected during ozone processing. Thus, the effects of ozonation on the nutritional properties of tomato juice should be considered by processors prior to its adoption as a preservation technique.

Today, over-consumption, pollution and resource depletion threaten sustainability. Waste management policies frequently fail to reduce consumption, prevent pollution, conserve resources and foster sustainable products. However, waste policies are changing to focus on lifecycle impacts of products from the cradle to the grave by extending the responsibilities of stakeholders to post-consumer management. Product stewardship and extended producer responsibility are two policies in use, with radically different results when compared for one consumer product, refrigerators. North America has enacted product stewardship policies that fail to require producers to take physical or financial responsibility for recycling or for environmentally sound disposal, so that releases of ozone depleting substances routinely occur, which contribute to the expanding the ozone hole. Conversely, Europe's Waste Electrical and Electronic Equipment (WEEE) Directive requires extended producer responsibili...

The measurements of electro-optical discharge characteristics and concentration of produced ozone were performed to evaluate the efficiency of ozone production in an AC surface dielectric barrier discharge (SDBD) in pure oxygen at atmospheric pressure. The discharge was driven in an amplitude-modulated regime with a driving AC frequency of 1 kHz, variable discharge duty cycle of 0.01–0.8 and oxygen flow rate of