摘要:

We have isolated 20 bacterial strains having shown a characteristic regrowth, starting from surface water treated and ozonized and then mixed with water of underground origin. After verification of the purity of these strains, we have attempted their preliminary identification by utilizing more than 60 tests.

ISSN:0191-9512    

DOI:10.1080/01919518608552287

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Experiments using dry oxygen in a wire–to–cylinder ozone generator, submitted to D.C. corona discharges show that technological parameters (diameter and composition of wire and cylinder, length of cell, gas flow and transit time of the gas) greatly influence ozone production. The cell geometry to be used depends on the polarity of the D.C. voltage applied to the wire and, for a predetermined design, the maximum ozone production rate will be obtained by seeking the most suitable gas flow. Lining up a series of optimized cells can give significant results.

ISSN:0191-9512    

DOI:10.1080/01919518608552288

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A study was made to obtain a better understanding of the manner in which preozonation affects trihalomethane (THM) formation with respect to humic acid, citric acid, and 11 aromatic compounds which were components of humic acid, all in dilute aqueous medium. Ozonation before chlorination is able tonotonly decrease, butalso increase the concentrations of THM precursors. The compounds which are inherently high THM precursors, such as resorcinol, aniline, salicyl-aldehyde, phenol, andp-hydroxybenzoic acid, are controlled with respect tothe increase inthe amount ofozone consumed, but the compounds which have essentially no or alow potential for chloroform formation, such as hydroquinone. salicylic acid, methoxybenzene. benzaldehyde. and benzole acid, produce their maximum THM levels at a certain value of ozone consumed. When 1mg of organic carbon consumes more than 8 mg of ozone, THM formation from thetested aromatic compounds isdepressed by ozone.

ISSN:0191-9512    

DOI:10.1080/01919518608552289

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

With the application of chlorine gas in drinking water treatment processing after the turn of this Century, great success was achieved. With the advance of analytical techniques in the field of trace matter, Rook (1)as well as Bellar, Lichtenberg and Kroner (2) succeeded in 1974 to establish the presence of chloroform and other chlorinated compounds in treated drinking water, namely as the result of chlorination. During tests to minimize the problems of chloroform, of chlorite and chlorate by the simultaneous addition of chlorine andchlorine dioxide, it was discovered that already a small dosage of chlorine dioxide was sufficient to reduce drastically the formation of chloroform andother trihalomethanes. The aimof future treatment techniques in Zurich is the preoxidation with ozone in place of chlorine and chlorine dioxide. Considering the mode of effect of the various oxidizing agents and the longer flow time through the biological activated carbon filters (asa result of the ozonation), ozone is – according to studies made by Grob and the Zurich Water Supply with ozonized Lake Zurich water – the most economical oxidation process with the best effect, i.e., without formation of toxic or carcinogenic substances. The pre– and/or intermediate oxidation with ozone surely will be the right way in the foreseeable future.

ISSN:0191-9512    

DOI:10.1080/01919518608552290

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0191-9512    

DOI:10.1080/01919518608552286

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor