The mysterious, bacteria “cobwebs” that were found years ago on cooling tanks for spent fuel at the Savannah River Site have been removed through an underwater vacuuming process, according to a recent press release.

The cobwebs were discovered in 2011 and found in the L Basin area of the Site. Samples were sent to the Savannah River National Laboratory and the University of South Carolina for testing.

Scientists at both facilities determined that the cobwebs were made up of a broad variety of bacteria and a few other types of microbes, according to the press release. The cobwebs were then monitored for growth patterns and changes.

While the cobwebs were never considered harmful, they did cover up the fuel bundle identification numbers that are regularly inspected to ensure proper inventory control.

A special kind of vacuum that uses filters, much like water filters found in homes, was used to remove the web-like material. Now, the filter cartridges will be sampled and characterized to determine the proper disposal path.

“The floor of the basin is regularly vacuumed to remove debris,” wrote L Basin Operations Support Engineer Rich Deible. “Vacuuming the cobwebs proved to be a new challenge, as we had never vacuumed the tops of fuel racks before.”

The Aiken Standard first reported on the discovery back in May 2013. At the time, DOE reported the cobweb material was collected by pumping it through bag filters on a cart located on zero level in the basin.

The bacteria was killed before being sent to the lab for testing. At the time, it was determined the cobwebs would be removed from the fuel bundles by underwater vacuuming for a corrosion precaution and to improve fuel bundle identification.

The scope of work was conducted by Savannah River Nuclear Solutions, the management and operations contractor for the Site.

Derrek Asberry is the SRS beat reporter for the Aiken Standard and has been with the paper since June 2013. He is originally from Vidalia, Ga., and a graduate of Georgia Southern University. Follow him on Twitter @DerrekAsberry.