摘要:

The objective of the study was to investigate the removal of synthetic organic compounds and THM precursors by two photocatalytic oxidation processes in the presence of synthetic polymers. H202/UV and O3/UV processes were tested on solutions of nitrobenzene and aquatic fulvic substances in the absence and presence of Polyethylene Oxide (PEO) and a Betz Polymer. The presence of high concentrations of PEO reduced the removal rate of nitrobenzene by competing with it for hydroxyl radicals. The presence of low concentrations of PEO did not significantly alter the removal rate of nitrobenzene and THM precursors. Experimental results indicated that even in the presence of the polymers, decomposition rather than coupling was the favored reaction pathway.

ISSN:0191-9512    

DOI:10.1080/01919512.1992.10555714

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A batch reactor was designed to study the effects of ozone on a complex industrial waste. The objective of the batch reactor was to allow a large mass of ozone to be applied to the waste without losses associated with gas sparging and assure better accuracy than expected from continuously bubbled gas systems. The reactor consisted of two parts: a 478.6 mL cylindrical section for holding effluent and a 1.078 L spherical section for the ozone/oxygen gas mixture. Ozone concentrations were measured at ambient temperature and pressure using the UV absorption method. Ozone diffusion into a reactive test solution in the static condition (during ozone charging of the spherical chamber) was limited to 0.5 mg of the 1,500 mg passed through the spherical chamber.

ISSN:0191-9512    

DOI:10.1080/01919512.1992.10555715

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

One commercial contact chamber which is designed for ozone disinfection has been tested for the following : determination of residence time distribution (RTD), measurement of dissolved ozone concentrations in water, and measurement total plate counts. Disinfection is achieved but this type of reactor is not ideal, due to dispersion of the residence time distribution. As these bubble contactors do not behave like plug flow reactors, it is possible to improve the hydrodynamics of ozone contactors with the use of static mixers. Experiments with ozone static mixers have been conducted.

ISSN:0191-9512    

DOI:10.1080/01919512.1992.10555716

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Ozonation of nucleic constituents in pure water in semi-batch reactor, showed that nucleobases and nucleosides behave in a similar way, regarding ozone consumption and inorganic nitrogen formation. Stoichiometric ratios were found about 1 mole of consumed ozone per mole of oxidized nucleobase and nucleoside, except for adenine and adenosine which presented a stoichiometric ratio near 3 moles per mole. Concerning inorganic nitrogen formation, we noted that the presence of primary amino groups induced ammonia and nitrate formations, but never more than one mole per mole of initial compound. Carbon dioxide and other end-products were released during ozonation of adenine and thymine. GC/MS analyses showed the presence of some simple end-products, such as oxalic acid, urea and carbamic acid. However trioxotriazine (or cyanuric acid) seemed to be an important end-product, issued from a cyclic trimerization of formamide followed by oxidation of carbon-nitrogen double bonds.

ISSN:0191-9512    

DOI:10.1080/01919512.1992.10555717

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This paper presents a practical design of a new ozone contactor (the deep U tube). It is a based on the modeling of upward and downward bubbly flow of air and water, derived from a balanced equation of continuity and momentum. Two hydrodynamic parameters are estimated: the void fraction and the frictional pressure drop. Experimental data carried out on full-scale plant and pilot plant are compared to theoretical results predicted by the model. Flow of the liquid phase is performed from tracer tests in order to determine the detention time which is introduced into the CT concept for disinfection. The influence of flow model shows that a plug flow reactor is more efficient than a CSTR; the DUT is close to plug flow.

ISSN:0191-9512    

DOI:10.1080/01919512.1992.10555718

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Preozonation facilities were installed at the Los Angeles Aqueduct Filtration Plant originally to enhance coagulation assistance (microflocculation). The Surface Water Treatment Rule will amend this primary purpose to meeting disinfection standards. Additional ozone generation equipment and a revised ozone system operating strategy will be required to accomplish these changed objectives. The topics discussed in this paper are the considerations surrounding the development of a successful, cost-effective operating strategy. The strategy proposed herein was based on data collected between January and July 1991. On-line process monitoring plans and automated system control logic are described.

ISSN:0191-9512    

DOI:10.1080/01919512.1992.10555719

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0191-9512    

DOI:10.1080/01919512.1992.10555713

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor