Abstract
The Surface Water Treatment Rule (SWTR) specifies the () calculation as the means by which disinfection efficacy, and therefore compliance, is determined. Baffle factors are used to scale the theoretical residence time of the water in a vessel to obtain the amount of time used for the calculation. The baffle factor formulation has been left to guidance and has been a topic of discussion. In this work, an extended baffle factor formulation is developed using disinfection contact system performance models that incorporate the methods imposed by and built into the SWTR. The performance models are based on chemical reactor analyses that have been validated extensively in the literature. A comparison made between the extended baffle factor formulation and methods that use hydraulic considerations alone shows that failing to account for the entire residence time distribution and disinfection kinetics can lead to significant errors. The result of this work is a baffle factor formulation that is compliant with the SWTR and is useful for troubleshooting utilities experiencing disinfection inadequacy or high levels of disinfection byproducts.
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Acknowledgments
This publication was supported by Environmental Health Specialist Network (EHS-Net) cooperative agreement number 5UE2EH000701 from the Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention. The authors would like to thank Teresa Boepple-Swider, P.E., Kevin Kenyon, P.E., and N. Scott Alderman, Ph.D., of the New York State Department of Health (NYSDOH) Bureau of Water Supply Protection and John Strepelis, P.E., New York State Department of Health, Central Regional Office, for their review.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 142 • Issue 7 • July 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Aug 24, 2015
Accepted: Nov 4, 2015
Published online: Feb 5, 2016
Published in print: Jul 1, 2016
Discussion open until: Jul 5, 2016
ASCE Technical Topics:
- Baffles (hydraulic)
- Continuum mechanics
- Disinfection
- Dynamics (solid mechanics)
- Engineering mechanics
- Environmental engineering
- Hydraulic engineering
- Hydraulic networks
- Hydraulic structures
- Hydraulics
- Inertia
- Kinetics
- Residence time
- Solid mechanics
- Statics (mechanics)
- Surface water
- Water (by type)
- Water and water resources
- Water management
- Water treatment
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