This study enabled the development of a conceptual design for a full-scale air stripping plant at a remote reservoir.
The conceptual design identified the following issues:
• Both water pumps and air blowers would be necessary.
• Noise reduction measures would be required for the commercially available water pumps and air blowers to
minimize impacts to adjacent residents.
• The height of the air strippers would need to be restricted to avoid visual impacts to adjacent residents.
• Available low-profile air strippers would meet height restrictions, but would also be limited in flow capacity for
• A large space would be required to accommodate multiple low-profile air stripping units.
To identify other improvement options and further reduce implementation costs, the LVVWD researched fine-bubble
aeration technology as an alternative to air stripping using a model based on Henry’s Law. The model results were also
well represented by the extended curve of air to water ratios versus TTHM removal derived by the Foundation project.
The benefits of using fine bubble aeration included no pumping requirements, energy efficient blowers, and reduced
space for equipment.
The design of a full-scale fine-bubble aeration treatment installation was recently completed and is currently under
construction at the Alta Reservoir site. The LVVWD performed worst-case air emission calculations of volatile organic
compounds to demonstrate air quality compliance. The treatment plant aims at 40% of TTHM removal during high
water age winter months when approximately 5 million gallons per day (mgd) of water is treated. It is also estimated
that over 20% of TTHM removal is achieved during low water age summer months when approximately 10 mgd of
water is treated. The total construction cost for this project is approximately $1.8 million. Construction is scheduled
to be completed in March 2010.
After the fine-bubble aeration system is installed and operational, field testing will be carried out to investigate TTHM
removal efficiency and reformation potential, to monitor water quality parameters such as temperature and chlorine,
and to study effects of varying air-to-water (A/W) ratios and other design considerations. Effects of reservoir aeration
on water mixing and the potential impact to pumping operations will also be evaluated. The field data will be used to
calibrate the aeration model and the distribution system TTHM model. The LVVWD long-term TTHM control plan will
be updated on an ongoing basis to ensure compliance with the Stage 2 DBPR.