摘要:

The disadvantage of chlorination of drinking water is the possible synthesis of toxic chlorinated fragments. In different cases UV can be an alternative to chlorination. The germicidal effectiveness of UV–radiation is in the 180–320 nm region with an optimum at 265 nm. Approximately 95% of the energy radiated by a low–pressure mercury arc is at the 253.7 nm line, so this source is the most effective one for germicidal applications. The germicidal effectiveness of a broadband source can be calculated. UV alone cannot decrease the concentrations of organic contaminants of the treated water. Quite promising are the systems where UV–radiation acts as a catalyst in oxidation reactions in order to decrease the organic contaminants.

ISSN:0191-9512    

DOI:10.1080/01919518708552146

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper reflects an investigation of the feasibility of photochemical generation of ozone by irradiating gases containing oxygen with Hg lamps of the highest performance emitting the 185 nm line. Besides the expected photostationary equilibrium, determining factors for practical yields in ozone generation by the 185 nm wavelength are : the reactor and gas temperature, the reactor geometry, and the gas composition, as well as the pressure.

ISSN:0191-9512    

DOI:10.1080/01919518708552147

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Advanced oxidation processes are defined as those which involve the generation of hydroxyl radicals in sufficient quantity to affect water purification. The theoretical and (practical yield of OH from O3at high pH, 03/H202, O3/UV and H2O2/UV systems is reviewed. New data is presented which illustrates the importance of direct photolysis in the O3/UV process, the effect of the H202:03ratio in the O3/H2O2process, and the impact of the low extinction coefficient of H2O2in the H202/UV process.

ISSN:0191-9512    

DOI:10.1080/01919518708552148

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Secondary effluent was irradiated with UV in a shallow bed reactor at flow rates between 10 and 30 m3. h-1using 1–3 high pressure mercury lamps. UV doses were calculated to range between 2.5 and 25 mJ.cm−2and inactivation of four groups of microorganisms was measured: E. noli, fecal streptococci, somatic coliphagesi and F–specific bacteriophages. Their relative UV resistance (in this order) was 1.0 : 1.5 : 1.1 : 2.3. Inactivation of F–specific (coliphages with 3 log10units required a dose of approx. 36 mJ.cm−2. Dose–response curves were linear with correlation coefficients of ca. 0.90, except for somatic coliphages, which seem to include a relatively UV–sensitive and a more resistant fraction. This study clearly demonstrated that F–specific bacteriophages are better indicator organisms with regard to viral inactivation by UV than classical parameters like E. coli. fecal streptococcior coliphages.

ISSN:0191-9512    

DOI:10.1080/01919518708552149

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Organic contaminants dissolved in deionized pretreated and raw mains water were reacted with ultraviolet light and ozone. Ozone first was used for partial oxidation followed by ozone combined with ultraviolet radiation to produce total oxidation. The reduction of TOC level and direct oxidation of halogenated compounds were measured throughout the treatment process. The rate of TOC reduction was compared for ozone injected upstream and inside the reactor.

ISSN:0191-9512    

DOI:10.1080/01919518708552150

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

When treating natural water, the simultaneous use of ozone and UV rays can lead to high level oxidation of the ozone–refractory organics. The main parameters affecting the efficiency of the O3/UV system are: the ozonation rate, the average UV radiation intensity, the pH measurement, alkalinity, and the type of compound to be oxidized.

ISSN:0191-9512    

DOI:10.1080/01919518708552151

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0191-9512    

DOI:10.1080/01919518708552145

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor