Bedford, N.S.

The Halifax metropolitan area has seen an extensive population expansion in the last 30 years. Bedford has seen some of the fastest growth, and as a result, the existing sewage treatment plant was not adequate for the increased demands. BMR carried out the structural design required to increase the plant capacity from 5 million gallons of effluent per day to 7.5 million gallons per day. To meet future demands, the design allows for expansion to 10 million gallons per day.

Design and construction of many of these components was complex due to the proximity of existing structures and the requirement that the plant be kept in operation throughout the expansion process.

This multi-faceted, 20 million dollar project includes the following elements:
New head-works building: A two-storey structure adjacent to the existing control building. Multi-level floor slabs were designed to support specialized equipment.
New clarifier tanks: Three primary clarifier tanks and two secondary clarifier tanks were constructed using cast-in-place concrete. A series of walkways span across the tanks to provide access for maintenance.
Modifications to existing aeration tanks: The process was modified making it necessary to construct a new oxygen-tight concrete roof slab over the existing aeration tanks. The columns supporting the new roof slab had to be strategically shaped and positioned not to disrupt the process.
Digester Complex: A new 86 foot diameter concrete digester tank was constructed. An existing digester tank had it's dome shaped concrete roof removed and replaced with a "floating" steel roof.
Miscellaneous structures: Equalization tank (located under the parking lot), ultraviolet treatment building, numerous channels and chambers.
Because of the plant's importance and required longevity, BMR used high quality structural concrete to prevent deterioration and cracking. Liners and coatings were used in critical areas to ensure resistance to the aggressive environment.