摘要:

The use of two Advanced Oxidation Processes, constituted by the combinations of ozone and UV radiation, and hydrogen peroxide and UV radiation, in the destruction of the herbicide cyanazine is presented. In both cases, the influence of the operating variables (initial herbicide concentration, ozone partial pressure or initial hydrogen peroxide concentration, temperature and pH) is discussed, and a comparison is made among the efficiencies of the different oxidizing agents used.

ISSN:0191-9512    

DOI:10.1080/01919519508547533

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper, another achieved example of Lunt's theory of chemical reactions in electrical discharges is emphasized. From an economic viewpoint, it is shown for a given mean value of the plasma temperature that the ozone yield of an air-fed cold plasma reactor presents an optimal value depending on the reduced electrical field, as expected from theoretical developments.

ISSN:0191-9512    

DOI:10.1080/01919519508547534

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A simplified engineering analysis developed by investigations of the energy levels and the data of ozone decomposition is presented. Experiments have been conducted by generating ozone from the same ozone generator by two ways and keeping the hydrodynamic conditions identical during ozonation. Ozonation conducted in various media such as gas, gas-liquid and gas-solid supports the assumptions of the presence of excited ozone species and variation in reactivity. The variation in reactivity linked with ozone generation shows an increase in the case of sawdust bleaching. The reactivity is the same for the removal of total organic carbon from water, and a higher ozone decomposition without significant reaction with methyl red solutions and coliform inactivation is observed.

ISSN:0191-9512    

DOI:10.1080/01919519508547535

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The impacts of ozone dose in the formation of biodegradable dissolved organic carbon (BDOC) were studied at the North Bay Regional Water Treatment Plant (NBR). Increasing the ozone to total organic carbon ratio to 0.45 (mg/mg) resulted in the formation of BDOC. Sedimentation and filtration/adsorption were effective in removing BDOC to non-measurable levels prior to the water entering the distribution system. Data from an on-going distribution system monitoring program indicate no discernible adverse impacts on microbiological parameters from using ozone during water treatment. Heterotrophic plate count (HPC) levels were similar before and after the use of ozone. Maintaining chlorine residual levels above 0.3 mg/L appears to be important for controlling HPC levels.

ISSN:0191-9512    

DOI:10.1080/01919519508547536

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A pilot study at the Snowbird Ski Resort in Utah evaluated feasibility of ozonation replacing chlorine and sulfur dioxide for oxidation of iron and manganese in groundwater. Ozonation also was tested for the removal of lead and cadmium, occurring at concentrations exceeding drinking water Maximum Contaminant Levels. An ozone dose of 2 mg/L, contacted with the water for 1 minute prior to filtration, was selected as optimum for iron and manganese removal from 0.4 mg/L and 40 μg/L, respectively, to below detection limits. Lead, copper, and arsenic also were removed to below detection limits. The removal of cadmium and zinc improved when ozone was contacted for 10 minutes. With metals removal through ozonation and filtration, taste and odor enhancement also were reported.

ISSN:0191-9512    

DOI:10.1080/01919519508547537

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The ozonation of water is a widely used technology within the water industry. Recent toxicological studies have shown that high bromate ion intake induces a high incidence of tumors in rats. Bromate ion formation from oxidation of water containing bromide ion was examined at nine treatment plants and one pilot. We found bromate ion (> 2 μg/L) in drinking water containing bromide ion when treated with ozone at pH greater than 7.0, even in the presence of ammonia. Bromate ion formation increased with the applied ozone dose. But bromate ion must be considered also as a byproduct of commercial sodium hypochlorite solutions. Under commercial conditions, chlorine dioxide and granular activated carbon had no effects on bromate levels.

ISSN:0191-9512    

DOI:10.1080/01919519508547538

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The indigo method developed by Bader and Hoigné for aqueous ozone analysis was modified to allow for both gaseous and aqueous ozone determination. Gas or water samples were extracted with a gas-tight syringe containing a known volume of indigo reagent. The modified procedure provided a more consistent basis for gaseous and aqueous ozone determination allowing for more accurate ozone mass balance calculations. Direct gaseous ozone UV absorbance with molar absorptivity of 3,000 M−1cm−1at 258 nm was used as primary standard to determine the molar absorptivity of the indigo reagent. The molar absorptivity of indigo reagent, assuming a 1:1 stoichiometric ratio for the reaction between indigo and ozone, was determined to be 23,150 ± 80 M−1cm−1, or approximately 16 percent higher than that of 20,000 M−1cm−1suggested by Bader and Hoigné. An independently calibrated membrane-electrode ozone monitor showed good correlation with indigo method results using the molar absorptivity value determined in this study. The apparent molar absorptivity of aqueous ozone at the wavelength of 258 nm measured by the modified indigo method increased from 2,400 to 3,600 M−1cm−1in the investigated ozone concentration range of 0.4 to 11.0 mg/L. This variation might have been caused by the inherent interference of unidentified ozone byproducts, which presence was supported with scanning spectra in the wavelength range of 200 to 300 nm.

ISSN:0191-9512    

DOI:10.1080/01919519508547539

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper describes the treatment of highly colored urban wastewater containing a high percentage of industrial effluents and a significant concentration of detergents. The kinetics of detergent ozonation were established through a series of pilot tests including variation of the ozone concentrations in the carrier gas. The results obtained concerning the optimum conditions of ozonation - treatment dose and contact time - have been used for the design of an industrial ozonation plant.

ISSN:0191-9512    

DOI:10.1080/01919519508547540

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor