摘要:

The disadvantage that chlorine as processing agent in the treatment of surface waters can lead to undesirable production of chlorinated hydrocarbon products, provided the impulse to involvement in alternate means of oxidation. This inevitably led the way to the means of oxidation used the most intensively in water treatment - ozone.

ISSN:0191-9512    

DOI:10.1080/01919519508547574

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper presents the design of a 1/5 scale model study of a five-stage counter-current ozone disinfection contactor. The selection of appropriate scaling laws is discussed and model test runs are presented and compared with the preliminary rule-of-thumb design. Simple modifications to the internal baffle design were tested leading to improved residence time characteristics.

ISSN:0191-9512    

DOI:10.1080/01919519508547575

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This research compares the role of ozone and the conjunctive use of ozone plus hydrogen peroxide in particle destabilization and particle aggregation, and improvement in filtered water quality. Particle destabilization was observed at all doses of ozone and ozone/peroxide studied, whereas aggregation was observed with ozone only at lower doses (> 2 mg/L) and in conjunction with ozone/peroxide (all doses studied). As compared to alum alone, the ozone-plus-alum and ozone/peroxide-plus-alum treatments provided improved flocculation and better filtered water quality. In addition, each of these preoxidations significantly reduced alum requirements. Overall, in terms of particle destabilization and aggregation; i.e., effectiveness as a coagulation aid, Ozone/peroxide performed better than ozone.

ISSN:0191-9512    

DOI:10.1080/01919519508547576

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This study investigated the formation of aldehydes after ozonation of three real and three model waters reconstituted from hydrophobic organic material. The four main aldehyde species formaldehyde, acetaldehyde, glyoxal, and methyl glyoxal were analyzed. Formaldehyde was the dominant species formed as a result of ozonation. The different waters varied greatly with respect to aldehyde production under similar treatment conditions. Studies conducted with model waters allowed for exploring aldehyde formation as a function of various water quality parameters. Overall, the hydrophobic organic extracts appeared to have greater aldehyde formation potential than the hydrophilic organics. Aldehydes were formed in direct proportion to the total organic carbon (TOC) concentration of the water at a 1:1 ozone-to-TOC ratio. Greater aldehyde formation was observed at lower ozonation pH values. Bromide ion and inorganic carbon added to model waters appeared to have no effect on aldehyde production. Finally, Assimilable Organic Carbon (AOC) measurements exhibited a strong correlation between aldehyde production and AOC production.

ISSN:0191-9512    

DOI:10.1080/01919519508547577

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A new useful index for predicting the maximum safe operating cycles of concentration in ozonated cooling systems is reported. This index utilizes simple, easily obtainable makeup water quality parameters including conductivity, alkalinity, calcium and magnesium hardness, chloride, and sodium and is easily calculated. The index provides greatly improved correlation with real-world-derived scaling tendencies in ozonated cooling systems compared to conventional scaling indices such as the Langelier Saturation Index (LSI), the Ryznar Stability Index (RSI), and the Puckorius Stability Index (PSI). A simplified version of the index utilizing only total hardness also can be used to establish quickly maximum operating cycles of concentration in well characterized, but very rapidly changing water supplies.

ISSN:0191-9512    

DOI:10.1080/01919519508547578

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A simulation program is described, tested and used, to predict micropollutant removal in an ozonation bubble tower with or without hydrogen peroxide addition. To compute the removal efficiency, we need to know the chemical reactivity between organic compounds and oxidant species (molecular ozone and hydroxyl radicals), the ozone mass transfer from the gaseous phase to the liquid phase (kLa) and the hydrodynamic model describing the reactor. In this case, we divide the reactor into three parts (water arrival, air arrival and intermediate zones). Each part is modelled using completely stirred tank reactors in series (CSTR).

ISSN:0191-9512    

DOI:10.1080/01919519508547579

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor