An innovative treatment method for an aqueous waste from the enhanced oil recovery process

Anaerobic treatment was evaluated to determine its effectiveness in treating a waste stream from the process of Enhanced Oil Recovery (EOR) to remove solubilized CO₂ (98%) and petroleum hydrocarbons (83%) using formate (2 g/L) and sucrose (2.5 g/L) as electron donors in two consecutive reactors. The method of evolutionary operation (EVOP) factorial design was applied to optimize the system and the net energy ratio (NER) of 3.7 was calculated for the system which showed a sustainable biogas production. This method is less complex than other competitive methods, and in addition to its low energy requirements, it can produce CH₄ from CO₂ as a clean source of energy. (author)