Geomembrane Technologies Inc. (GTI) was selected to design and build a new retractable, structurally supported geomembrane cover system for Vallejo. This cover system consisted of a composite sheet of high-strength, coated fabric tensioned across a series of low-profile aluminum arches which span the tank opening. Intermediate aluminum walkways spanning the tank were used to divide the fabric cover sections into appropriate lengths for easy retractability.
“We wanted the covers first for odor control,” says Tim Tekippe, Project Manager at Carollo Engineers. “But we also needed the covers to be easy to open for access to the tanks for sampling, scheduled maintenance, and repairs. We felt structurally supported covers would be the best system for the plant’s needs because of the better access they provide over other systems, such as floating covers. We first looked at rigid type covers such as aluminum and fiberglass, but both of these proved more labor intensive for operators to gain access to the basins.”