Absorption and biodegradation of hydrophobic volatile organic compounds: determination of Henry's constants and biodegradation levels.

Biodegradation of three volatile organic compounds (VOCs) was studied. Toluene, dimethylsulphide (DMS), and dimethyldisulphide (DMDS) were introduced into flasks filled with emulsions of Di-2-EthylHexylAdipate (DEHA) in water, containing biomass (activated sludge). The VOC concentrations were analysed in the gas, organic and aqueous phases, and compared to the initial VOC quantities introduced in order to deduce their consumption by biomass. Toluene and DMDS were completely consumed, and then removed from the gas and the organic phases, except when DEHA and water are in the same volume ratio, which appears to be extreme environmental conditions for bacterial growth. The high DMS volatility resulted in an important gas loss, leading to a lower amount of DMS available for activated sludge growth. For all the VOC experiments, some components, characteristics of the DEHA degradation, including 2-ethylhexanal, 2-ethylhexanol, 2-ethylhexanoic acid and adipic acid, were identified.