摘要:

A single-bubble model of mass transfer in gas-liquid systems enables the estimation of transfer efficiencies under different process conditions. In particular, it can be applied to simulate the effects of bubble size, value of the mass transfer coefficient, kinetics of reactions taking place in water and depth of the contact chamber. The results of such modelling in terms of transfer efficiency are presented for physical and chemical absorption of ozone in water at different hydrodynamic conditions (bubble size, water temperature, water depth in the contact chamber, and initial ozone concentration in the bubbles). The results of computations are compared with some reference data on ozone absorption in water in industrial-scale contact chambers.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555761

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The use of high concentration ozone (HCO) in potable water treatment has been examined at laboratory scale with a gaseous concentration of 19% w/w. This has been compared with conventionally generated ozone at 1.5% w/w. The results of the study have shown that greater transfer efficiencies and higher ozone residuals are possible with HCO. In addition, faster rates of atrazine removal and significantly greater reductions in color and trihalomethane formation potential (THMFP) were observed with HCO.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555762

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Total inactivation of ten microorganisms inoculated in a model wastewater was achieved by ozone treatment at laboratory scale. Microorganisms selected included four viruses, three non-sporulated bacteria, two sporulated bacteria and one fungus, employed in vaccine preparation for animals. Viruses resulted in the most readily-inactivated microorganisms and sporulated bacteria the most resistant strains, althoughSalmonella typhimurium, a non-sporulated bacterium, showed an unusually high resistance. Inactivations followed a second-order kinetic law, depending on both ozone and microorganism concentrations. In each case, kinetic parameters which characterize the inactivation process were measured experimentally.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555763

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The objectives of this research were to investigate the reactivity of humic acid (HA) with ozone and to evaluate its effect on decoloration and biodegradability. Reagent HA was selected as a target compound, and the change in overall water quality parameters, molecular weight distribution, color and biodegradability during ozonation were investigated. Partial oxidation such as decoloration was observed, though the complete destruction represented by TOC removal was not significant. The rate of ozone usage decreased as the reaction proceeded. Degradation to the lower molecular weight fragments was confirmed by ultrafiltration. The close relationship between color and fragmentation was verified. Decoloration was represented by a pseudo-first order reaction. Formic, acetic, oxalic and glyoxylic acids were identified by HPLC and ion chromatography as typical low molecular weight organic acids. The biodegradability of ozonated HA solutions, represented in terms of the ratio of BOD5to TOC, was improved.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555764

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Degradation of phenolic compounds in Kohtla-Järve oil shale ash dump wastewater (North-East Estonia) by O3, O3/UV, O3/H2O2, O3/H2O2/UV, O3/TiO2and O3/TiO2/UV treatment in a countercurrent film absorber was studied experimentally. The mathematical model and the simulation algorithm of the processes were developed. The random search optimizer was applied to evaluate the values of reaction rate constant, mass transfer enhancement factor, stoichiometric coefficient and volatilization coefficient for organics into the process models. The evaluated coefficients for individual phenolic compounds, total content of phenolic compounds and COD for different oxidation systems are presented and discussed. “Operation” of the simulated film absorber (based on the evaluated coefficients) and the experimental column are compared.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555765

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The potential to form BrO3−as a byproduct during ozone treatment of raw water containing bromide ion is a major concern for utilities planning to use ozone. The proposed BrO3−Maximum Contaminant Level (MCL) of 10 μg/L in the USA has been established largely by using ion chromatography. A spectrophotometric method based on the oxidation of chlorpromazine in the presence of BrO3−has been developed. The method detection limit (MDL) in reagent water is 0.8 μg/L BrO3−The procedure has an operating range of 1 to 40 μg/L BrO3. The precision of the method is calculated to be better than 2.5% with an accuracy within ± 1 μg/L BrO3−. Details of the method are presented along with data gathered by ion chromatography using borate and carbonate eluants; chlorpromazine post column studies; and low level capillary electrophoresis studies.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555766

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Bromate ion occurs during ozonation of bromide-containing waters. The current WHO guideline for bromate ion is 25 μg/L. Bromate analysis in drinking waters can be performed by various techniques. However, given the commonly low concentrations of bromate ion found in drinking waters, the classical methods do not fit for bromate analysis in most cases.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555767

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The polarity effect of microdischarge and the characteristics of ozone generation were studied using electrical and optical methods, paying attention to the distribution of microdischarges in terms of time and space and the effect of dielectric surface on microdischarge. As a result, the phenomenon in which a chain of microdischarges occurs in a brief period of time could be observed for the first time. In addition, it was found that the microdischarge characteristic, collective microdischarge phenomenon, and ozone yield vary according to the surface condition of the dielectric electrode used. The ozone yield was high with a glass surface and low with a ceramic surface.

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555768

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

ISSN:0191-9512    

DOI:10.1080/01919512.1995.10555760

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor