Bioremediation of a phenol-contaminated soil as affected by nutrients content

Over the past years, the increasing number of aromatic hydrocarbons-contaminated sites has increased the need to develop and improve technologies allowing hazardous pollutants to be removed and therefore contaminated soils to be detoxified. Among the different available technologies, the most promising ones seem to be the bioremediation techniques, that convert the contaminants into simpler and generally less toxic compounds by means of microbial activity. For remedial actions to be successfully applied, conditions suitable for microbial growth must be provided: aeration, moisture content, pH, temperature, and nutrients. The aim of the present paper was to investigate the influence of nutrients on phenol and p-nitrophenol biodegradation using a slurry-phase process. The influence of nutrients on biodegradation of phenol- and p-nitrophenol-contaminated soils in a slurry phase process was studied. Nutritive salts were added at several concentrations to achieve optimal and moderate nutrient levels. A check on salt desorption from uncontaminated soil indicated that sorption processes can be neglected, with all disappearance of phenols being due to biodegradation. Addition of nutrients shortens the disappearance time of phenolic compounds, with the disappearance time at the optimal salinity level being nearly two times faster than that observed at moderate nutrient levels.