Trimet procured AEC to perform complete closure and new construction of its fuel system at the Center Street Bus Station in Portland Oregon. The general scope work consisted of decommissioning eight (8) UST’s of varying sizes as well as the installation of four (4) new UST’s each 20,000 gallons. It was critical that the TriMet bus facility continued operation through the project so AEC first designed and constructed a temporary 40,000 gallon AST fuel system to service the TriMet fleet. There was an approximate 200+ buses per night that required fueling. The temporary system included 2 x 20,000 gallon lined baker storage tanks and used them as AST fuel storage tanks. The baker tanks were placed in liners in the unlikely event there was a fuel leak. Next we piped a fill system so that a tanker truck could fill the baker tanks and designed a temporary piping system to run the existing dispenser then tied it all together. Once this temporary system was functioning, AEC kept the system running while we decommissioned the old USTs and installed the 4 new ones. Next, we capped off the old system and drained/cleaned all 8 tanks. Once drained and cleaned, we excavated down to the tops of all the tanks and started with decommissioning activities. Once removed to Oregon State decommissioning regulatory requirements, we took soil samples and found petroleum contamination. AEC excavated the contaminated soil and hauled it to a Subtitle D Landfill for proper disposal. In order to place the new tanks in the dig, we excavated the area deeper and longer to fit the 4 new USTs that we were to place. It was determined that the piping plan was not feasible so AEC re-designed the piping system to go a different way and re-engineered higher capacity turbines to be able to accomplish the amount of fuel flow the client wanted. We installed all turbines and manholes to the tanks and piped fiberglass underground piping and manifolded the systems together. The piping was then transitioned from underground to aboveground into the fuel house. We re-piped the steel overhead piping back to the existing piping and reinstalled to the dispensing system.
At last, AEC was able to perform the startup for the new system. Once the new system was up and running, we removed and capped the temporary system and transferred all fuel in the temporary system and into the new system. Finally, we cleaned the temporary tanks and systems and removed them from the site. Site restoration involved replacing all the concrete back to pre-existing conditions.