Experimental and modeling approach to study sorption of dissolved hydrophobic organic contaminants to microbial biofilms

Abstract

IntroductionBiofilms may significantly influence the distribution of hydrophobic organic compounds (HOC) in heterogeneous aqueous systems and, hence, their residence time, mobility and fate in such systems. When the solid phase provides only poor sorption properties (sewer systems, water supply systems, sand filters, membranes, mineral particles in surface waters and aquifers), the evolution of a microbial biofilm on its surface may provide an important sink and reservoir for hydrophobic contaminants delivered by the aqueous phase. Accumulation of HOC in such biofilms and the increased contact time with bacteria residing in these biofilms may allow adaptation of microorganisms and mineralization of these trace pollutants. For these reasons, the evolution of a biofilm may be essential to retain and to remove HOC in such systems. If these biofilms are detached, however, they could turn into a source for HOC. When the solid phase itself has good sorption properties (soil, activated carbon), a biofilm coverage may act as a barrier that slows down the mass transfer of a hydrophobic compound from the dissolved to the particulate phase. In this case, biofilm growth may hamper rather than improve the removal of HOC.To quantitatively assess the importance of biofilm coatings on surfaces exposed to water for the fate of HOC in these systems, knowledge on the partition coefficients (K D ) as well E-mail address: thorsten.reemtsma@tu-berlin.de (T. Reemtsma). WAT E R R E S E A R C H ] ( ] ] ] ] ) ] ] ] -] ] ]Please cite this article as: Wicke, D., et al., Experimental and modeling approach to study sorption of dissolved hydrophobic organic contaminants to microbial biofilms, Water Res. (2007),

Memory Effect of Aquatic Biofilms in the Partitioning of Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) in Water Streams

“…These cycles might have been disregarded during those investigations [27], [88]. In other cases, as previously explained, the use of not suitable partition coefficients (K oc and K ow ) could cause the overestimation of the retention times of HOC in aquatic biofilms [19], [30]. The main results produced by this work fully matches what has been observed by previous field and laboratory studies [29], [53], [89].…”

“…The octanol-water partition coefficient (K ow ) and the organic carbon partition coefficient (K oc ) are the most common parameters used to study the sorption properties of biofilms. The K oc is calculated by the ratio between the distribution coefficient biofilm-water (K d ), which is normalized to the dry weight, and the organic carbon fraction (f oc ) of the biofilm [30]. The K oc of phenanthrene and pyrene for microbial biofilms has been reported as equal to 12.400 (L/Kg) and 38.000 (L/Kg) respectively [30].…”

“…The K oc is calculated by the ratio between the distribution coefficient biofilm-water (K d ), which is normalized to the dry weight, and the organic carbon fraction (f oc ) of the biofilm [30]. The K oc of phenanthrene and pyrene for microbial biofilms has been reported as equal to 12.400 (L/Kg) and 38.000 (L/Kg) respectively [30]. The octanol-water partition coefficient K ow is the value obtained by the ratio of the molar concentrations of a compound taken at the equilibrium of the partitioning between water and n-octanol.…”

Metaldehyde removal from drinking water by adsorption onto filtration media: mechanisms and optimisation

“…8 The adsorption efficiency of SSFs or microbial biofilms has been reported for some micropollutants. [9][10][11] Inactive biofilms were found to be less effective for the removal of odorous compounds such as geosmin or pharmaceuticals, 12 although the mechanisms for biological metaldehyde degradation in water remain unknown, biocoenosis has been demonstrated in aquatic sediments 13 and soils 14 suggesting that biodegradation occurs in natural systems, and therefore possible in engineered bio-physical processes. Metaldehyde degradation is exothermic, producing 3370 kJ mol −1 during thermal combustion, suggesting that it could be a useful carbon source for microbial growth.…”

Enhanced Biotransformation of Fluoranthene by Intertidally Derived Cunninghamella elegans under Biofilm-Based and Niche-Mimicking Conditions

“…The rate of substrate flux to a bacterial cell is determined by the substrate concentration gradient, which becomes steeper as a cell approaches a surface with sorbed substrate, and this increased substrate concentration permits greater activity of attached cells than suspended cells including the functioning of extracellular hydrolytic enzymes (27)(28)(29). When the solid phase provides poor sorption properties, the evolution of a microbial biofilm on its surface may provide an important sink and reservoir for hydrophobic contaminants delivered by the aqueous phase (30). Biofilms can form a significant sink for hydrophobic organic contaminants (HOCs) in systems with low organic carbon content and high surface areas (31).…”