ULTRAVIOLET DISINFECTION IN THUNDER BAY: ONSITE COLLIMATED BEAM TESTS TO ESTABLISH A DESIGN BASIS FOR UV TREATMENT AFTER TWO STAGE BIOLOGICAL AERATED FILTRATION
Abstract:The biological aerated filtration (BAF) installation at the Thunder Bay Atlantic Avenue Water Pollution Control Plant (WPCP) is the first municipal installation of its kind in Ontario and one of the largest operating BAF installations in North America. It is now intended to further extend the Atlantic Avenue WPCP to include ultraviolet (UV) disinfection of the treated effluent instead of the current chlorine gas disinfection.
In early 2006 a series of collimated beam tests were undertaken with BAF effluent from the plant. The samples were shipped to external certified laboratories, where they were analyzed the next day. The data obtained was quite inconsistent and considered not adequate for use as a design basis for the future disinfection facility. It was therefore decided to undertake on-site collimated beam tests.
The tests allowed the designer to:
Confirm feasibility of UV disinfection
Obtain a representative data set and a higher confidence factor in the data
Observe the influence of BAF operating conditions and variations
Observe the influence of rain events
Involve and train City staff in light of the future project
It appears that the multiple barrier configuration of the Atlantic Avenue WPCP (Chemically enhanced Primary clarification → BAF Carbonaceous removal stage → BAF Nitrification stage) is capable of producing a high quality effluent, which can be disinfected to the disinfection limit with a relatively moderate dose:
Average UV transmittance (UVT) of the plant effluent during the test period: 58%
Average total suspended solids (TSS) concentration in the plant effluent during the test period: 6.7 mg/l
Average required UV dose for disinfection target: 14.5 mWs/cm2
Maximum dose based upon 95 percentile data: 21.0 mWs/cm2
Document Type: Research Article
Publication date: January 1, 2007
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- ingentaconnect is not responsible for the content or availability of external websites