Petroleum sludge formation and its treatment methodologies: a review

Abstract

Different petroleum operations produce huge amount of oil sludge annually. For instance, US EPA estimates the annual sludge production of each US refinery of 30,000 tons, while the average oily sludge produced from petrochemical industries in China is estimated about 3 million tons per year. In the last year, our center could recover about 30,206 barrels of raw oil from 32,786 barrels of tank bottom sludge (TBS) for different petroleum companies. This sludge causes huge economic losses besides its negative environmental impacts. The accumulation of sludge in the tanks results in reducing the tanks’ capacity for storing liquid crude, accelerating the corrosion of the tanks, delay in the production schedule, and disturbing the whole production operation. There are diverse treatment methodologies such as solvent treatment, addition of certain chemicals, and centrifuging. Of course, the environmental regulations and the overall cost limitations are very important in deciding the preferred applicable method(s). Although several works handled the problem of sludge deposition and treatment from different aspects, we intend to introduce a different work. First, composition, formation, types, and properties of TBS were reviewed. Then, environmental and economic problems caused by TBS were revised. At last, different methodologies applied for treatment of oily TBS to recover oil and safe disposal of hazardous remains were investigated focusing on the most straightforward and environmentally friendly protocols. It is expected that this review attracts the experts in petroleum chemistry, and other relevant fields and provides a comprehensive understanding of current sludge control and treatment research. Graphical abstract

Exploring the Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Production Potential of Total Petroleum Hydrocarbon Degrading Bacteria Using Oily Sludge Waste as Feedstock

“…Petroleum refineries, with a production capacity of 105,000 drums per day, produce approximately 50 tons of oily sludge per year . Globally, more than 1 × 10 7 tons of oily sludge is produced per year. − Alkane, cycloalkane, and polycyclic aromatic hydrocarbon (PAH) constitute the TPH fractions of oily sludge and impart toxicity to the surrounding environment, humans, and animals. ,− Moreover, seepage of oil from oily sludge stored in pits contaminates subsurface soil and aquifers . The Research Conservation and Recovery Act (RCRA) and the United States Environmental Protection Agency (USEPA) have considered such oily waste as hazardous waste. , There are several reports indicating the application of bioremediation approaches for treating oily sludge. ,− It would be preferable to recover some valuable byproducts along with their treatment.…”