Case studies biodegradability, enhancement

In the next few sections, several case studies will be discussed to illustrate the different types of xenobiotics at various contaminated sites, the ways of enhancing their biodegradation/biotransformation techniques, and the verification of the results. 

The tensile modulus of a polymeric material has been shown to be remarkably improved when nanocomposites are formed with layered silicates. In the case of biodegradable polymer nanocomposites, most studies report the tensile properties as a function of clay content. In most conventionally filled polymer systems, the modulus increases linearly with the filler volume fraction, whereas for these nanoparticles much lower filler concentrations increase the modulus sharply and to a much larger extent. The dramatic enhancement of the modulus... 

Ozone is applied in three-phase systems where a selective ozone reaction, oxidation of residual compounds and/or enhancement of biodegradability is required. It can be used to treat drinking water and waste water, as well as gaseous or solid wastes. Especially in drinking water treatment full-scale applications are common, e. g. for particle removal and disinfection, while in waste water treatment sludge ozonation and the use of catalyst in AOP have been applied occasionally. Current research areas for three-phase ozonation include soil treatment and oxidative regeneration of adsorbers. Ozonation in water-solvent systems is seldom studied on the lab-scale and seems favorable only in special cases. In general, potential still exists for new developments and improvements in ozone applications for gas/watcr/solvent and gas/waler/solid systems. 

Noordman et al. [38] studied the effect of the biosurfactant from R aeruginosa on hexadecane degradation. They determined that the biosurfactant could enhance biodegradation if the process is rate-limited as in the case of small soil pore sizes (6 nm), where the hexadecane is entrapped and is of limited availability. The rhamnolipid stimulates the release of entrapped substrates (if mixing conditions are low such as in a column) and enhances uptake by cells (if the substrate is available). This could then become important in the stimulation of bacterial degradation under in situ conditions. 

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