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A multiphase computational fluid dynamics (CFD) model has been developed to addressthe major components of ozone disinfection processes: contactor hydraulics, ozonedecay, and mass transfer. The model was applied to simulate ozone profiles and tracerresidence time distributions of ozone contactors at the DesBaillets WTP in Montreal,Canada. The CFD model was applied to illustrate and improve ozone residual monitoringstrategy. The modelling results show that ozone residuals at the cross section of the outletof each chamber are very sensitive to monitoring point selection. Residuals at differentlocations can differ by an order of magnitude. The residual variation is affected bymultiple factors, including water/gas flow rate, temperature, baffling conditions, etc. Thepotential optimum locations of ozone sensors can be predicted by CFD modelling. TheCFD model was also used to study the factors affecting tracer residence time distribution(RTD). The results suggest that the method of tracer injection can slightly affect tracerRTD results while sampling location has a significant influence on tracer RTD predictionor measurement. The Tsub10/sub values calculated from the CFD predicted RTD curves atdifferent outlet locations could have more than 10% variation. Therefore, multiplesampling points should be employed during tracer tests if possible. It is concluded thatthe CFD approach is an efficient tool for improving measurement or prediction of CTvalues, and it can be used in various ways for operating/designing full-scale ozonedisinfection systems. Includes 33 references, figures.

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Edition: Vol. - No. Published: 11/01/2006 Number of Pages: 18File Size: 1 file , 700 KB