Fuel Quality Case Studies

Tank Cleaning and Filtration Services

Northeast Petroleum Distributor


Superior was contracted to perform tank cleaning and filtration services at 27 locations with a total of 48 underground storage tanks (USTs), in Maine, New Hampshire, and upstate New York. A list of tanks was provided to Superior noting reoccurring problems such as slow pumps, water intrusion, and clogged filters.

Superior coordinated with our client to develop a scope of work. After assessing each site and problematic tank, Superior conducted pre-cleaning activities, which included gathering an initial Veeder Root reading and tank bottom samples. A tank bottom sweep was performed on each of the problematic tanks removing the water, sludge, biological matter, and settled debris. The waste product was segregated and placed in a sealed drum for disposal. After waste removal, the product in each tank was pumped through a series of filters removing any remaining impurities including suspended water. Upon completion, a final Veeder Root printout was obtained as well as final tank bottom samples. This process was conducted under numerous quality control measures, protecting the initial investment of our client and ensuring that only the waste had been removed.

Due to the new ethanol-based fuels, Superior recommended that the fuel in each of these problematic tanks be tested semi-annually. In addition, Superior recommended that all the damaged fill and Veeder root caps be replaced and the direct spill basin drains be plugged to help prevent further water intrusion.

Water Intrusion Assessment

Michigan Based Petroleum Jobber

Superior was contracted to investigate possible water intrusion points that were thought to be contributing to bacteria and particulates in a diesel underground storage tank (UST) resulting in slow flow and frequent filter changes at the dispenser. The monitoring system was not detecting water and recent tank tightness testing on the UST indicated the tank was not exhibiting the presence of a leak. However, manual stick measurements conducted by the client on a routine basis showed significant water intrusion, especially after heavy rainfall. Based on this information our technicians conducted a thorough investigation.

Superior began the investigation by extracting samples from multiple ports. Visually the samples were cloudy and contained substantial amounts of water and microbial growth. The automatic tank gauge (ATG) probe was dry tested and found to be in good working order. Further inspection of a nearby monitoring well revealed the groundwater level was unusually high, making the system highly susceptible to water intrusion. Superior staff then looked for possible water intrusion points as well as possible causes for the monitoring system malfunctions.

During the assessment, multiple factors contributing to the failure of the monitoring system were found. Superior submitted the following recommendations to ensure the monitoring system would function properly:

  • Clean floats and probe shaft to allow for proper readings
  • Adjust ATG to appropriate height
  • Repair and adjust the interstitial float

Superior submitted the following recommendations to eliminate water intrusion:

  • Replace fill port lids
  • Remove direct drain valve and plug spill bucket drain holes until manual drain valves could be installed
  • Replace interstitial and probe caps

After the above recommendations were carried out and following 3 months with periods of heavy rainfall, the client reported that no water had entered the UST. Superior was then contracted to clean the UST and remediate the fuel using biocide and filtration.

© Superior Environmental Corp
1128 Franklin Street
Marne, MI USA 49435
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