Modeling ozone mass transfer in reclaimed wastewater
Pan Jiang1, Hsiao-Ting Chen, Roger W Babcock
1University of California, Los Angeles, CA 90095-1593, USA.
Summary
This study evaluated ozone mass transfer in reclaimed water using a pilot plant. Oxygen can effectively surrogate ozone transfer, with minimal impact from water contaminants.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Mass Transfer Processes
Background:
- Ozone is a powerful oxidant used in water treatment.
- Understanding ozone mass transfer is crucial for optimizing treatment efficiency.
- Reclaimed water presents unique challenges for mass transfer due to contaminants.
Purpose of the Study:
- To evaluate ozone mass transfer characteristics and reaction kinetics in reclaimed water at pilot scale.
- To assess the feasibility of using oxygen as a surrogate for measuring ozone mass transfer.
- To develop a mathematical model for ozone transfer and concentration in reclaimed water.
Main Methods:
- Conducted pilot-scale tests over three years in a 40-L/min system.
- Performed nonsteady-state mass-transfer analyses for oxygen and ozone.
- Measured superficial gas flow rates from 0.13 to 0.40 m/min.
- Determined the psi factor (ratio of ozone to oxygen mass-transfer coefficients).
Main Results:
- Oxygen transfer rate reduction in reclaimed water was minimal (10-15%) compared to tap water.
- A mathematical model accurately described ozone transfer rate and steady-state concentration.
- Ozone decay was effectively modeled as a pseudo first-order reaction.
Conclusions:
- Oxygen can be reliably used as a surrogate to measure ozone mass transfer in reclaimed water.
- Contaminants in reclaimed water have a minor impact on oxygen transfer rates.
- The developed model provides an accurate method for predicting ozone behavior in reclaimed water treatment.
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