Waste Oil Remediation Case Study
A Strawn formation unit that operated in Wise County, Texas, contained a 300-barrel capacity tank that was used to hold waste oil. For ten years, bad bottoms and spilled oil from throughout the unit had been collected and stored in the tank. Management decided to terminate the practice of collecting waste oil in the tank. The field superintendent was told to clean the tank and return it to normal stock tank operation. The 242 barrels in the tank was a solid mass at ambient temperatures and could not be drained. Numerous attempts to clean the tank using conventional chemical and heat methods were unsuccessful.
In July 1994, Bio Tech designed and implemented a microbial treatment program to remediate the waste oil tank. The goals of the microbial treatment program were to:
1.) Modify waste oil composition so it could be drained from the tank.
2.) Clean the tank with zero entry.
3.) Return the tank to normal stock tank operation.
The Bio Tech treatment program consisted of inoculating 50 barrels of fresh water with a specifically designed blend of Para-Bac microbes (See Waste Oil Composition). The solution was injected into the tank through the load line and the tank was circulated weekly for 1.5 hours with a bobtail water truck. After 40 days into the treatment, additional microbes and nutrients were added to the tank and the circulating program was resumed.
Waste Oil Composition
The Bio Tech microbial remediation program was very successful:
Eighty-three days after the initial treatment, all of the waste oil had been removed from the tank (See below).
The cost of the tank remediation including material, labor and truck costs totaled $4,354, which was less than the $5,000 budgeted fir the project. The first load of oil sold out of the tank after it had been returned to normal operation groundout at 4/10% BS&W and had a 9” bottom.