Ozonization multiple-stage

Multiple-stage ozonization seems to be more effective than single-stage ozonization, both followed by biodegradation, for DOC ehmination in treatment of reservoir waters and secondary effluents of a domestic wastewater treatment plant . The fate of O3 in water ozonization consists of a fast reaction with the DOC and a slow first-order decay of unreacted O3. A method for optimization of a two-stage water ozonization process is based on control with a FIA unit, where the ozone concentration is continuously measured by oxidation of indigotrisulfonate(8) . The various fractions of DOC (in the ppm range) may react with the traces of bromide (sub-ppm) found in natural waters, as this anion... 

Another consideration connected with these multiple effects is the optimum placement of the ozonation stages within a whole treatment scheme. The efficiency of every ozonation unit and the ozone demand depend on the water and waste water quality produced by the preceding process units (e. g. particle removal or biodegradation). Ozonation will also have pronounced effects downstream in the treatment sequence, e. g. improved biodegradation of dissolved organics. 

Thus, the results presented show that the first stage of addition of ozone to multiple bonds may proceed by two different pathways on the singlet plane. The reaction on the triplet plane of potential energy is also probable. The ratio of the rates of the reactions (1) and (2) may vary over a wide range. The reaction (1) share in the overall ozonation is 100% for olefins. For TFE and diphenylethylenes the reaction (2) prevails. For styrenes and dienes, the reaction rates are comparable. 

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