A large company’s primary wastewater holding tank had approximately 8 feet of heavy, oily sludge accumulated at the bottom. This was estimated to be about 40,000 barrels of hydrocarbon waste. Refinery operations were jeopardized. If water levels in the tank were lowered as needed, the volume of grease and oil in the refinery wastewater would be much higher than allowed according to the county wastewater discharge permit. The tank had lost close to 30 percent of its storage capacity. The tank had to be cleaned.
Historically, this tank cleaning operation was very expensive. Similar tank cleaning operations at this refinery had cost up to $2 million. These costs included waste removal, centrifuge, dry and haul as much as 1,000 tons of hazardous waste for out-of-state disposal. The company was willing to try almost anything to keep the expense from going over $1.5 million.
Aster Bio microbes along with nutrients and a specially formulated surfactant package were sold by a key distributor and used to breakdown and remediate the oily sludge. The thick buildup was dissolved and the large volume of waste was remediated. First, the bioremediation products separated the sludge from the oil so the remaining oil could be skimmed off and recycled or converted back into product. Then the microbial solutions reduced the hydrocarbon levels until it was safe and legal to discharge the water.
The project was completed in a few weeks by a few employees for less than $300,000. The tank was not opened and no hazardous waste was created. More than 4,000 barrels of oil were recycled and saved. The wastewater effluent quality was improved.