Biodegradation of PAH contaminated soil and sludge using non-ionic surfactants
- Publication Year:
- Repository URL:
- Biodegradation.; Sewage--Purification--Biodegradation.; Environmental Sciences
thesis / dissertation description
Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent environmental pollutants contaminating a large number of industrial and Superfund sites. Low solubility and sorption to solid surfaces limit biodegradation rates of PAHs in the environment. Bioremediation of these compounds have been previously tested with partial success. In the present study, aerobic biodegradation of three PAHs (fluorene, phenanthrene, and pyrene) has been studied in shaker flasks, batch fermenter, and bioslurry reactor, in the presence of non-ionic surfactants. A mixed bacterial culture derived from both a refinery sludge and an activated sludge was used as the seed population in the degradation studies. A non-ionic surfactant, Makon 10 (at a concentration above the CMC), was selected for most of the studies, based on screening a number of surfactants in solubilization and respirometric experiments. PAH biodegradation was examined in both the presence and absence of an initially clean soil, as well as in the presence of a real PAH-contaminated refinery sludge. The results obtained from batch experiments indicated an increase of 2 to 3 orders of magnitude in the solubility of the tested PAHs, in the presence of surfactant. Furthermore, provided the surfactant concentration was maintained in the reactor to overcome mass transfer effects, biodegradation of all three PAHs proceeded to the detection limit, even in the presence of soil or sludge.