City of Victoria
In the summer of 2012, Ocean Concrete / Lehigh Hansen contacted Westbrook Consulting regarding design and inspection services for a semi-automated sedimentation control system for their downtown Victoria operation. Historically the site was located on Ocean Concrete property and on adjacent waterfront leased land owned by the Federal Department of Transport (DOT). The lease on the DOT lands was coming to an end and the DOT lands were being remediated as part of the Rock Bay contaminated site clean-up project. Ocean Concrete took the challenge of relocating the portion of their plant that was located on the DOT lands as an opportunity to construct a versatile sediment and contaminant control system. The system collects sediment and excess cement powder for re-use / processing and treats runoff water for suspended solids, as well as balances pH prior to release back to the City of Victoria storm drain system. Options for re-use of treated or partially treated runoff water for re-use in the batch plant were also required.
Westbrook Consulting designed an initial course grit catchment area which was easily maintainable using onsite loaders. Runoff water from the grit catchment area was directed to a robust lift station where it was pumped to a series of above ground settlement / flocculation tanks. The settlement / flocculation tanks consisted of an initial sump that was maintainable using an onsite loader. The initial tank discharges to a carbon dioxide injection tank where the pH is brought into acceptable range. The CO2 injection tank is also capable of holding filtration or flocculation curtains to assist in trapping suspended solids from the flow. The final release from the treatment tanks is controlled by an actuated valve that will only open when the pH within the treated water is within acceptable limits.
Construction commenced in late 2013 and was completed in the spring of 2014.
To date, Ocean Concrete has been very pleased with the operation and flexibility of the treatment system. As a bonus, they have been able to qualify for the Rainwater Rewards Program, as part of the recent City of Victoria storm water control and tax bylaw. As true testament to the client’s satisfaction, Westbrook has been recently contacted by the client to design a similar facility at another of their concrete plants on Vancouver Island.