A paradigm shift in the management of oil refinery wastes

Abstract

Untreated oil refinery effluent is detrimental to the environment, and historically, aquatic ecosystems are paying the price due to the negligence of petroleum refineries. Apart from water-in-oil and oil-in-water emulsions, the sludge profusely contains solids that can clog the soil matrix if discharged straightforwardly. The inherent polyaromatic and allied hydrocarbon content and the higher water requirement generate a significant wastewater load. Owing to a projected 32% energy demand from oil industries by 2030, it will be a prudent option for the refineries to establish biorefinery in their production processes and expedite the potential opportunities to remediate the sludge into valuable by-products. Off-late various options like advanced oxidation processes (AOPs), microwave-assisted wet air oxidation, and Fenton's oxidation have been tried out by researchers to treat spent liquor from the process and enhance the BOD/COD ratio to increase the biodegradability and lessen the noxiousness for biological treatments. This study is a synchronous compilation of all the possible treatment techniques for oil refinery sludge. It discusses the most economical sludge treatment option considering SDG 7, highlighting a sustainable alternative to reduce the net energy expenditure of the plant. © 2024 Elsevier Inc. All rights reserved.