Full Description

The objective of this project was to identify the disinfection calculation method (i.e., model) thatbest describes the actual inactivation achieved in a continuous-flow ozone contactor. Thisobjective was accomplished by conducting disinfection tests at a pilot-scale ozone contactorowned by the Southern Nevada Water Authority (SNWA). The testing was conducted using B.subtilis bacterial spores as the model microorganism spiked into the feed water to the ozonecontactor. The measured inactivation of the spores was compared to that predicted by threedifferent disinfection models:Conventional CefflluentT10 (CeffT10) Method;Integrated Residual Method; and,Segregated Flow (SFA) Method.To apply the models, three steps were implemented:Step 1 - identify the disinfection rate kinetics of the test microorganism;Step 2 - identify the values of the operational parameters under which the tests wereconducted (e.g., flow rate, ozone residual values); and,Step 3 - utilize the model to calculate the inactivation of the test microorganism under thespecific operational parameters.Step 1 was accomplished using bench-scale testing with the specific goal of identifying theinactivation coefficient, k10, of the test organism with ozone. Step 2 was accomplished byconducting tracer tests on the ozone contactor to characterize its hydraulics, as well as byoperating the ozone contactor under different ozone dose conditions and collecting ozoneresidual samples from various locations in the contactor. Step 3 was accomplished by utilizingthe data gathered in Steps 1 and 2 and calculating the inactivation of the test organism at eachof the sets of contactor operating conditions.The study reported herein was partially funded by the Awwa Research Foundation under itsTailored Collaboration Funding program (project number 3168). This manuscript includes someof the results obtained. The full project results will be presented in the project final report whichcan be obtained from the Research Foundation. Includes tables, figures.

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Edition: Vol. - No. Published: 11/01/2007 Number of Pages: 16File Size: 1 file , 510 KB