Ozone and ultraviolet radiation

Seek alternatives to chlorine for water treatment and disinfecting applications. For example, sodium hypochlorite has been used both in industrial and municipal water treatment applications (Somerville, 1990). Other alternatives include calcium hypochlorite, ozone, ultraviolet radiation and heat treatment (Negron, 1994 Mizerek, 1996). 

An Evaluation of the Use of a Combination of Ozone-Ultraviolet Radiation and Hydrogen Peroxide to Remove Chlorinated Hydrocarbons from Groundwater at the U.S. Department of Energy Kansas City Plant FY 1988 Annual Report... 

Smith RC, Prezelin BB, Baker KS, Bidigare RR, Boucher NP, Coley T, Karentz D, MacIntyre S, Matlick HA, Menzies D, Ondrusek M, Wan Z, Waters KJ (1992) Ozone depletion ultraviolet radiation and phytoplankton biology in Antarctic waters. Science 255 952-959 Sommaruga R, Psenner R (1997) Ultraviolet radiation in a high mountain lake of the Austrian Alps air and underwater measurements. Photochem Photobiol 65 957-963 Swanson AK, Druehl LD (2002) Induction, exudation and the UV protective role of kelp phlorotannins. Aquat Bot 73 241-253... 

Giese, A. C., H. L. Leighton, and R. Bailey. Changes in the absorption spectra of proteins and representative amino acids induced by ultraviolet radiations and ozone. Arch. Biochem. Biophys. 40 71-84, 1952. 

Modulation of Solar Ultraviolet Radiation and Photochemistry by Stratospheric Ozone, aerosols and tropospheric ozone... 

The Photochemical Activity and solar Ultraviolet Radiation (PAUR I) and Photochemical Activity and solar Ultraviolet Radiation Modulation Factors (PAUR II) projects had the aim of studying various aspects of ultraviolet radiation and photochemistry interrelationships. PAUR I aimed at studying the interrelationships between total ozone, UV-B radiation, aerosol load, air pollutants, photodissociation rates of N02 and 03 and tropospheric ozone. PAUR II has the aim of studying the interactions between UV-B, total ozone, tropospheric ozone and photochemical activity in the presence of alternating maritime and Saharan aerosols. The present paper presents the main concepts underlying the two projects, the approach followed and a brief overview of some of the results obtained so far. Further, the main results of PAUR I that are relevant to tropospheric ozone chemistry over the Eastern Mediterranean are presented. 

Hader, D. P, The effect of enhanced solar UV-B radiation on motile organisms, in Stratospheric Ozone Reduction, Solar Ultraviolet Radiation and Plant Life, Worrest, R. C. and Caldwell, M. M., Eds., Springer-Verlag, Berlin, 1986, 223. 

Microbial fouling is best dealt with before biofilm becomes mature. Biofilm protects the microorganisms from the action of shear forces and biocidal chemicals used to attack them. Microbes can be destroyed using chlorine, ozone, ultraviolet radiation, or some non-oxidizing biocides (see Chapters 8.2.1,8.2.2, 8.1.8, and 8.2.5, respectively). An effective method to control bacteria and biofilm growth usually involves a combination of these measures. Specifically, chlorination or ozonation of the pretreatment system, followed by dechlorination to protect the membranes, or UV distraction followed by periodic sanitation with a non-oxidizing biocide used directly on the membranes. 

Army. 1983b. Tertiary treatment of effluent from Holston AAP industrial liquid waste treatment facility III. Ultraviolet radiation and ozone studies TNT, RDX, HMX, TAX, and SEX. Frederick, MD U.S. Army Medical Bioengineering Research and Development Laboratory, Fort Detrick. Document no. AD A137672. 

Caldwell MM, Camo LB, Warner CW, Flint SD. Action spectra and their key role in assessing biological consequences of solar UV-B radiation. In Worrest RC, Caldwell MM, eds. Stratospheric Ozone Reduction. Solar Ultraviolet Radiation and Plant Life, 1986 87-111 Springer-verlag, NY. 

Ozone is a gas that occurs naturally in relatively large concentrations in the upper-atmospheric layer known as the stratosphere. The stratosphere is between 5-10.6 mi (8-17 km) to about 31 mi (50 km) above the earth s surface. Stratospheric ozone is very important to life on the surface of Earth because it absorbs much of the incoming solar ultraviolet radiation, and thereby shields organisms from its deleterious effects. Since the mid-1980s, there has been evidence that concentrations of stratospheric ozone are diminishing as a result of complex photochemical reactions involving chloroflno-rocarbons (CFCs). These persistent chemicals are synthesized by humans and then emitted to the lower atmosphere, from where they eventually reach the stratosphere and deplete ozone. 

Ultraviolet radiation and ozone Expansion and compression joints... 

Considerable research was done on the application of an ozone-producing lamp for domestic refrigerators. It was necessary to find a balance between the amount of ultraviolet radiation and ozone so that mold and bacteria on the food and refrigerator wall would be destroyed, while the level of food odors and the transfer of food odors to other foods would be greatly reduced without causing reactions in certain sensitive foods. 

There are four vapor phase treatment processes (a) thermal destruction, (b) catalytic incinerahon, (c) ozone destruction with ultraviolet radiation, and (d) granular carbon adsorption (GAC). Processes a-c are not widely utilized due to cost and/or effectiveness of treatment. Thermal destruction is an effective process, but the operating cost is very high due to energy requirements. Catalytic incineration, shown in Fig. 7, has lower energy requirements compared to the thermal destruction process, but it is not effective in eliminating low levels of chlorinated organic compounds. Ozone destruction with an ultraviolet radiation process has limited performance data available as a result, the performance of this process must be examined in a pilot study for the particular VOC in question in order to determine operational parameters. The most commonly used vapor phase treatment process for VOC is carbon adsorption. 

Water that is biologically contaminated is treated to remove bacteria, viruses, fungi, and parasites, by aeration, chlorination, ozone, ultraviolet radiation, or a combination of these methods. In the process of purification, decontamination by-products (DBPs) are produced. These are chemicals that are themselves toxic. DBPs are discussed in Section 8.9. 

The free chlorine acts as a catalyst and a single chlorine atom may break down tens of thousands of ozone molecules before it returns to the troposphere. In the troposphere, chlorine reacts with hydrogen and forms hydrogen chloride that is rained out. Since ozone absorbs biologically-damaging UV radiation before it reaches the earth s surface, its depletion increases the risks associated with UV exposure. Ultraviolet radiation and over-exposure are linked with skin cancers, cataracts, and suppression of immune system response. In 1985, this problem started to attract everyone s attention by the dramatic announcement of the discovery of a hole in the ozone layer over... 

In the beginning there was no oxygen, but there was ultraviolet radiation and water. Without an ozone layer, the intensity of ultraviolet radiation... 

Ozone is an important component of the upper atmosphere, where it screens out ultraviolet radiation and so protects us from the effects of these high-energy rays. For this reason, depletion of stratospheric ozone is a major scientific concern, -xc (Section 18.2) In the lower atmosphere, ozone is considered an air pollutant and is a major constituent of smog. <3 (Section 18.2) Because of its oxidizing power, ozone damages living systems and structural materials, especially rubber. 

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