The challenge was to find an appropriate secondary containment lining material that was resistant to biodiesel. Biodiesel consists of long chain alkyl (methyl) esters and is typically produced by chemically reacting lipids (e.g., vegetable oil, animal fat [tallow]) with an alcohol. Biodiesel can be used alone or blended with diesel fuel.
The biodiesel at the Kyoto fuel facility was tallow based. There was little or no research on the resistance of geomembrane against this kind of fuel and that presented us with the challenge of finding a suitable material. The other challenge on this job was the constructability of a leak proof containment cell with over 40 square pedestals to be sealed (see picture). Sealing around a circular pile is a lot easier and takes less labour hours when compared to a sealing a square pile.
Due to complexity of installation, PVC based products were initially considered due to their flexible characteristics. However, little was known about the resistance of PVC based materials against biodiesel. After conducting a battery of tests it was evident that PVC based lining materials tended to get softer when exposed to biodiesel and were not appropriate as a secondary containment liner in a long term application. Layfield also tested HAZGARD ®535 (Fire Code Complaint liner) against biodiesel which did not show any significant changes in material properties and was accepted as the choice of material.
To tackle the issue of sealing the square concrete pedestals our construction group came with an innovative solution were bolts were driven into the corners (3” away from the edge) of the pedestals. The HAZGARD® 635 geomembrane was then placed around the bottom of pile and attached with batten bars fastened to the bolts. A neoprene gasket was included to create a tight seal.
This project was completed on time and budget. A timely assessment on the product ensured “the right material for the right application”. Our installation crews did a phenomenal job of attaching the liner to the concrete pedestals and performed leak tests to make sure the seal was leak proof.
Biodiesel is the next generation fuel; hence there is a strong need to test all other geomembrane materials against this kind of fuel. Layfield is already ahead in the game as we have tested several materials and determined which geomembrane products are suitable for biodiesel. Layfield is also working on a geomembrane that will meet the new UL Canada specification S 668 which will regulate resistance to biodiesel and other chemicals for secondary containment liners.