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EPCOR Cloverbar Ostara Nutrient Recovery Facility

EPCOR Cloverbar Ostara Nutrient Recovery Facility
Date: 2015

The largest nutrient recovery facility in Canada, a partnership between EPCOR Water Services and Ostara Nutrient Recovery Technologies, recovers phosphorus from the Edmonton Waste Management Centre’s wastewater streams to transform it into an eco-friendly fertilizer. General contractor PCL Construction Management chose AGRA Foundations Limited for the foundations work portion of the project. The equipment to be installed inside the building required a very dense distribution of the piles to achieve the necessary load capacity, as well a range of pile cut-off elevations, ranging up to 3.5 m below working grade. The soil conditions on site were difficult with a heterogeneous sequence of clay, sand, and gravel overlaying clay shale bedrock and slough and seepage in the sand and gravel.

Solution:

AGRA’s design build solution was able to fulfill the client’s specific needs, while effectively addressing soil conditions and site constraints. The open-ended driven pipe piles proved to be an effective solution in these difficult soil conditions, while eliminating the risk and higher costs associated with the installation of cast-in-place concrete piles in fluvial sand and gravel.
The AGRA team used PDA testing to validate pile capacity and termination criteria. Reach and versatility of the driving equipment selected for the works allowed for the excavation of the different building levels to be carried out prior to driving the piles, reducing the challenges and costs inherent to completing this task after the pile installation. Installing piles at cut-off elevation level made this solution much more cost effective compared to CIP piles by eliminating the need to use temporary casing. The method was equally superior to CFA piling, eliminating the material waste inherent to the installation of piles with deep cut offs. The top pile connection details were another solution presented by AGRA that resulted in a significant cost and time saving to the client.