%0 Journal Article
%T Improvement of Bioremediation Performance for the Degradation of Petroleum Hydrocarbons in Contaminated Sediments
%A Laura Rocchetti
%A Francesca Beolchini
%A Maurizio Ciani
%A Antonio Dell'Anno
%J Applied and Environmental Soil Science
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/319657
%X Microcosm bioremediation strategies were applied to sediments contaminated with hydrocarbons. Experiments were performed in aerobic conditions in a single-step treatment and in a two-step anaerobic-aerobic treatment. In aerobic conditions, either inorganic nutrients or composts were added to the microcosms, while, in the first anaerobic phase of the two-step experiment, acetate and/or allochthonous sulfate-reducing bacteria were used. After the treatment under anaerobic conditions, samples were exposed to aerobic conditions in the presence of compost. In the aerobic treatments, 81% hydrocarbon biodegradation was observed after 43 days in the presence of inorganic nutrients. In aerobic conditions in the presence of mature compost, hydrocarbon biodegradation was 51% after 43 days of treatment, whereas it was 47% after 21 days with fresh compost. The two-step experiment allowed us to obtain a hydrocarbon degradation of 91%, after a first anaerobic step with an inoculum of sulfate-reducing prokaryotes. 1. Introduction Marine sediments represent the principal sink for a wide variety of organic contaminants, and the materials that are periodically dredged from harbors potentially contain many contaminants. A number of technologies have been developed aimed at the reduction of the contamination present in soils and subsequently have also been applied to sediments. Among these, biological treatments are having more importance in the last years, mainly because of the low environmental impact, the costs (in general cheaper than other cleanup technologies), the capability to destroy organic contaminants, and the possibility of beneficial use of treated sediments [1]. In fact, dredged material can be used for beneficial utilizations, as remediation/creation of upland habitat, beach nourishment, or building materials [2]. Bioremediation technologies may consist in stimulation of autochthonous microorganisms (adding nutrients, amendments, increasing oxygen concentration) [3¨C5] and introducing allochthonous degrading prokaryotes [6¨C8]. One of the advantages of using natural microorganisms is that they could produce several compounds, such as biosurfactants, useful for the acceleration of hydrocarbon degradation processes [9, 10]. These compounds are made up of a hydrophilic part and a hydrophobic part, and this structure allows them to increase the bioavailability of different compounds, such as hydrocarbons [11, 12]. The present work deals with two bioremediation studies to reclaim dredged materials contaminated with petroleum hydrocarbons. Laboratory microcosms were
%U http://www.hindawi.com/journals/aess/2011/319657/