Assessing Technical and Economic Feasibility of Complete Bioremediation for Soils Chronically Polluted with Petroleum Hydrocarbons Roberto Orellana # , Andres Cumsille # , Claudia Rojas, Patricio Cabrera, Michael Seeger * , Franco Cárdenas, Cristian Stuardo and Myriam González Molecular Microbiology and Environmental Biotechnology Laboratory, Department of Chemistry and Center of Biotechnology, Universidad Técnica Federico Santa Maria, Valparaiso, Chile # Contributed equally * Corresponding author: Michael Seeger, Molecular Microbiology and Environmental Biotechnology Laboratory, Department of Chemistry and Center of Biotechnology, Universidad Técnica Federico Santa Maria, Valparaiso, Chile, Tel: 56322654236; Fax: 56322654782; E-mail: michael.seeger@usm.cl Rec date: May 07, 2017; Acc date: May 17, 2017; Pub date: May 19, 2017 Copyright: © 2017 Orellana R, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Petroleum hydrocarbons are highly persistent in the environment and represent a significant risk for humans, biodiversity, and the ecosystems. Frequently, hydrocarbon-contaminated sites remain polluted for decades due to a lack of proper decontamination treatments. Although bioremediation techniques have gained attention for being environmentally friendly, cost-effective and applicable in situ, their application is still limited. Each polluted soil has particularities, therefore, the bioremediation approach for a contaminated site is unique. Bioremediation cost studies are usually based on hypothetical assumptions rather than technical or experimental data. The research aims of this study were to clean-up chronically hydrocarbon-polluted soils using aerobic and anaerobic bioremediation techniques and to carry out an economic evaluation of the most promising bioremediation treatments. The results showed that aerobic biostimulation with vermicompost and aerobic bioaugmentation plus air venting were the most effective treatments, degrading 78% and 73% of total petroleum hydrocarbons (TPH) in chronically hydrocarbon- polluted soils after six weeks, respectively. In contrast, no significant degradation of hydrocarbon was observed by anaerobic biostimulation treatments with lactate and acetate. An economic evaluation of the aerobic treatments were carried out. This analysis revealed that the cost of treating one cubic meter of soil by biostimulation is US$ 59, while bioaugmentation costs US$77. This study provides a clear structure of costs for both aerobic bioremediation approaches based on projections made from these lab-scale incubations. These values represent the first step towards a better understanding of the feasibility of such treatments at larger scales, which is crucial to move on industrial bioremediation of soils chronically polluted with petroleum hydrocarbons. Keywords: Bioaugmentation; Bioremediation; Biostimulation; Petroleum hydrocarbon; Hydrocarbon-degrading strain; Acinetobacter; Pseudomonas Introduction Petroleum based products are the major source of energy in industry and daily life [1]. Leaks and accidental spills during the manipulation, transportation, and storage of petroleum products are frequent, therefore, petroleum hydrocarbon contamination is a global concern [2,3]. Petroleum hydrocarbons are highly persistent in the environment and represent a signifcant risk for human health, impacting the biodiversity and the ecosystems around the world [4,5]. In 2002, the European Union estimated 18,142 contaminated sites, where 53% of them were afected with mineral oil and common petroleum substances [6,7]. In Australia, from 160,000 contaminated locations, 60% comprised hydrocarbon-contaminated sites [8]. Frequently, a large fraction of those sites remains polluted for decades, mainly due to the lack of appropriate decontamination treatments [9]. Bioremediation is the process that applies living organisms to degrade, reduce or detoxify pollutants [10,11]. Bioremediation techniques are ofen based on (i) natural bioattenuation, using indigenous microorganisms to degrade a pollutant; (ii) biostimulation, changing variables to enhance pollutant degradation by native communities; or (iii) bioaugmentation, using exogenous hydrocarbon clastic microorganisms [12]. Although bioremediation has gained increasing attention for being an environmentally sustainable, cost- efective and a permanent alternative for treatment of contaminated soils with a wide range of pollutants, its contribution for the clean-up is still limited [13,14]. Nutrient limitations, insufcient availability of electron acceptors, and the lack of an efcient catabolic machinery from native microbial communities are among the main factors preventing bioremediation for massive application [4,11,15]. Other remediation techniques, such as physical separation, in-situ chemical injection, application of ozone or electrochemical degradation have been seldomly applied due to their high costs and energy consumption, along with physicochemical alterations of the remediated soils [16]. Te ultimate goal of bioremediation of petroleum-contaminated sites is to degrade hydrocarbons into carbon dioxide and water [17]. However, the assessment of efcacy and efciency of bioremediation of a wide range of hydrocarbon-contaminated soils has become rather challenging. Indeed, the available regulations to assess when a site should be classifed as cleaned are variable. For instance, the maximum concentration limit of total petroleum hydrocarbons (TPH) allowed in Spain is 50 ppm for soils, while in the United States the action levels range from 10,000 to 100 ppm [18,19]. However, 100 ppm was the most commonly applied clean-up level [18,19]. Tereafer, the policies for management of contaminated sites have evolved from a total concentration to a risk-assessment standpoint. Tis perspective is based on the potential risks to humans and ecosystems that would occur under “standardized” condition [7,20]. Tis complexity makes Orellana et al., J Bioremediat Biodegrad 2017, 8:3 DOI: 10.4172/2155-6199.1000396 Research Article OMICS International J Bioremediat Biodegrad, an open access journal ISSN: 2155-6199 Volume 8 • Issue 3 • 1000396 Journal of Bior emediation & Biodegradation J o u r n a l o f B i o r e m e d i a ti o n & B i o d e g r a d a t i o n ISSN: 2155-6199