A $550 million expansion of the Annacis Island Wastewater Treatment Plant is intended to meet increasing demand.
"It's what we call a growth project," said Mark Ferguson, a division manager of water and wastewater treatment engineering and the person responsible for the design and construction of Metro Vancouver's water and wastewater treatment projects.
The current facility is designed to treat waste for one million people.
The stage five project will expand the plant to handle an additional 250,000 people.
Metro Vancouver is about four years into the project and is currently working on the detail design for phase one, which is expected to be complete next fall.
Overall, the project is about 60 per cent complete on the design, Ferguson said.
Phase one target completion is 2018. The first phase includes expansion of primary tankage, secondary clarifiers, solid contact tanks and additional odour facilities.
Metro has already tendered and awarded some construction contracts for it, such as the ground improvement (GI) and the solids contact tanks blowers. The $47.3 million GI contract went to JJM Construction Ltd./Geopac Inc.
Ferguson said the next general contract will be for the primary/secondary tanks, odour control and clarifiers.
The estimated cost for this contract is between $150 and $160 million.
He said this could be broken down into several contracts due to bonding and pricing.
Metro would prefer one contract as it is easier to co-ordinate, Ferguson said, however, such a large contract might make it difficult for contractors to get bonding.
"On this job we are hoping we can keep it on one," he said.
Ferguson explained one of the challenges of the project is carrying out major expansion construction at an operating facility.
Existing operations must be maintained to meet Ministry of Environment standards.
The phase one GI contract involves utility relocation, the installation of 9,000 stone columns and jet grouting, which all needs to be done without damaging existing infrastructure.
Furthermore, Stage five expansion must be co-ordinated with other projects at the facility, including improvements to back up power and co-generation facility ($47 million) which generates 50 per cent of the plant's electricity; major clarifier maintenance ($20 million) and expansion of the Annacis outfall ($130 million).
All the Annacis projects total about $750 million.
The plant serves much of the Tri-Cities, Burnaby, Maple Ridge, Delta, Surrey, Pitt Meadows, Langley and White Rock. The last expansion was in 1998.