Hydrocarbons removal from real marine sediments: Analysis of degradation pathways and microbial community development during bioslurry treatment

• Published in: The Science of the total environment 2022-09, Vol.838, p.156458-156458, Article 156458
• Main Authors: Avona, A., Capodici, M., Di Trapani, D., Giustra, M.G., Greco Lucchina, P., Lumia, L., Di Bella, G., Rossetti, S., Tonanzi, B., Viviani, G.
• Format: Article
• Language: English
• Subjects: Bioremediation; Contaminated marine sediment; Hydrocarbon pollution; Microbial community; Slurry reactor
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.156458

In this study, real marine sediments polluted by petroleum compounds were treated by means of a bioslurry pilot scale reactor. The treatment performance was evaluated by measuring the removal of total petroleum hydrocarbon (TPH), coupled to further analyses required to understand the mechanisms involved in the biodegradation process. The maximum TPH-removal efficiency reached 86 % at the end of experiments. Moreover, high throughput 16S RNA gene sequencing was used to describe the microbiome composition in sediment prior to, and after, bioslurry treatment, in order to identify the taxa mostly entailed in the TPH removal process. The raw sediment was mostly colonized by members of Sulfurimonas genus; after bioslurry treatment, it was noticed a shift in the microbial community composition, with Proteobacteria phylum dominating the remediation environment (high increase in terms of growth for Hydrogenophaga and Sphingorhabdus genera) along with the Phaeodactylibacter genus (Bacteroidetes). Furthermore, the assessment of gaseous emissions from the system allowed to quantify the volatile hydrocarbon component and, consequently, to obtain a more accurate evaluation of TPH-removal pathway by the bioslurry system. Finally, phytotoxicity tests on sediment samples highlighted an increase of the treated sample quality status compared to the untreated one. [Display omitted] •High removal efficiency of total petroleum hydrocarbons (TPH) with bioslurry reactor•Volatilization contributed only marginally to contaminant removal.•Taxonomic groups originally present with low abundance developed predominantly.•Phytotoxicity tests showed higher quality characteristics after bioslurry treatment.