Case Study Tank Cleaning

Micro-Bac successes

Canadian Oil Company puts microbiological to the Test

Tank Bottom Cleaning

Micro-Bac International Inc. 3200 N. IH 35 Austin, Texas 78681

Ph: 512-310-9000 Fax: 512-310-880 Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it www.micro-bac.com

Description of Site:

A Canadian oil company's naphtha storage tank had several inches of solidified ferrous

oxide and a quantity of residual free product. The tank was 220 feet in diameter and 60 feet

in height. The objective was to clean the tank bottom in a cost-effective manner (removing

hydrocarbons and oxide), eliminate hazardous confined space entry by maintenance

personnel, and prevent the escape of vapors from the tank.

Treatment:

The tank was first flushed with fresh water, leaving 200 to 300 gallons of visible floating

product, plus substantial additional product left in the sludge. A rotating liquid delivery

system was installed and M-1000HH microbes were introduced. The mechanism was

operated for 10 hours per day.

Results:

After 13 days, the company reported that where corrosion had been covered by the water,

it had dissolved to a liquid and could be pumped out. This was done, and the majority of

the material that had covered the tank floor was removed.

It was also observed that near the center of the tank, where the water had not covered the

oxide during the treatment, oxide material remained attached to the floor. This material

covered an area about 35 feet in diameter and was 1 to 2 inches thick. Since this material

had not received a microbial treatment, it was removed in the conventional manner and

required 4 more days. It is estimated that it would have taken more than 50 days to complete

the cleaning manually.

After all material had been removed from the tank, it was observed that in the areas where

M-1000HH came in contact with the floor of the tank, it was clean and appeared to have been

"sand blasted".

LEL vapor readings were also taken every 2 hours of the work day. By day #5 they had

dropped to 65% of LEL. By day #10 they had dropped to 30% of the LEL. On day #13, LEL

readings had dropped to 0%.

Conclusions:

It was estimated that the cleaning would have cost $200,000 or more using the manual

method. Utilizing M-1000HH reduced this amount to less than 30% of this figure.