Effective anaerobic treatment of produced water from petroleum production using an anaerobic digestion inoculum from a brewery wastewater treatment facility.

Produced water is a major waste problem in oil production yet it also represents a potential water source if treated properly, especially in arid regions. In this study, we investigate the anaerobic treatability of an oil-produced water with extremely high chemical oxygen demand (COD) and total dissolved organic carbon (TOC) from Wyoming's Greater Green River Basin using anaerobic microcosms inoculated with a microbial consortium derived from a brewery wastewater treatment facility. The results demonstrate that for this water and an appropriate microbial inoculation, high-COD/TOC can be effectively removed with concomitant energy recovery as a form of methane. 93% and 89% of the COD and TOC were removed with a final high methane yield of 33.9 mmol/g carbon (848 μmol/g carbon/day). Chemical analyses showed that the ethylacetate-extractable compounds were much more amenable to biodegradation than the CH 2 Cl 2 extractable compounds. Furthermore, compounds that were added during drilling and completion remained in the water and contributed significantly to the COD and anaerobic degradability. This study demonstrates that produced waters are amenable to anaerobic biological treatment and also that thorough chemical analyses are necessary to fully understand the potential for treatment. ga1 • Oil-produced water with extremely high COD and TOC can be effectively treated anaerobically. • 93% COD and 89% TOC removal was achieved with microbes from a brewery wastewater facility. • A final high methane yield of 33.9 mmol/g carbon (848 μmol/g carbon/day) was achieved. • High COD concentration may be due to glycerol added during well drilling/completion. [ABSTRACT FROM AUTHOR]