Hydrocarbon Toxicity towards Hydrogenotrophic Methanogens in Oily Waste Streams

Hydrocarbon-containing wastes and wastewaters are produced worldwide by the activities of oil gas industry. Anaerobic digestion has potential to treat these waste streams, while recovering part its energy as biogas. However, hydrocarbons toxic compounds that may inhibit microbial processes, particularly methanogens. In this work, toxicity hexadecane (0–30 mM) towards pure cultures hydrogenotrophic methanogens (Methanobacterium formicicum Methanospirillum hungatei) was assessed. Significantly lower (p < 0.05) methane production rates were only verified in incubations with more than 15 mM represented up 52% 27% inhibition for M. hungatei, respectively. The results obtained point out 50% methanogenic activity would likely occur at concentrations between 5–15 >30 respectively, suggesting effects from aliphatic not during anaerobic treatment. Hydrocarbon further assessed incubating an sludge H2/CO2 presence a complex mixture (provided addition oily groundwater treatment system). Specific decreased 1.2 times hydrocarbons, but relatively high (~30 still assays containing inoculum (without H2/CO2), reinforcing systems waste/wastewater.