Simple Bioremediation Treatments for the Removal of Polycyclic Aromatic Hydrocarbons (PAHs) from the Polluted Desert Soil of Kuwait PDF

Keywords

Kuwait, bioremediation, polluted desert soil, polycyclic aromatic hydrocarbon, bacteria

Abstract

A soil microcosm test was designed to evaluate the influence of mixing polluted desert soil with clay soil (which is used as an amendment material and for immobilization of bacterial cells) on the biodegradation of petroleum polycyclic aromatic hydrocarbons (PAH). Residual PAHs in this type of polluted soil were quantified by using GC analysis. At the beginning of the experiment 16 PAHs were resolved, of which the mutagenic and carcinogenic compounds fluoranthene and pyrene were more frequent than the other PAHS (14% and 12.4% respectively). Results of total PAH biodegradation show that mixing this polluted desert soil with clay soil or its water extract stimulated the biodegradation of 85.8%-89.1% of these compounds. This is in contrast to 61.7%-75.5% in the absence of clay soil. Moreover when the mixed bacterial culture was immobilized in this clay soil 94.4% of total PAHs were degraded. On the other hand, the free cells of the mixed culture succeeded to remove only 75.5% of these compounds. In this study the six-ringed PAHs were completely degraded in the presence of clay soil. A particularly notable distinction between the immobilized culture (13) and the other treatments in this biodegradation study is the greater efficiency of the immobilized culture to degrade the individuals of the 16 PAHs, especially the carcinogenic compounds: fluoranthene, pyrene, chrysene, benzo(a)pyrene and dibenzo(a,h)anthracene. These results lead to the conclusion that mixing the polluted desert soil with clay soil and/or its water extract seems to be a simple cost effective bioremediation method.