Reclamation of river dredged sediments polluted by PAHs by co-composting with green waste

• Published in: The Science of the total environment 2016-10, Vol.566-567, p.567-574
• Main Authors: Mattei, P., Cincinelli, A., Martellini, T., Natalini, R., Pascale, E., Renella, G.
• Format: Article
• Language: English
• Subjects: Co-composting; Composting; Dredged sediments; Environmental Restoration and Remediation - instrumentation; Environmental Restoration and Remediation - methods; Geologic Sediments - chemistry; Green Chemistry Technology; Green wastes; Italy; PAHs contamination; Polycyclic Aromatic Hydrocarbons - chemistry; Reclamation; Rivers; Water Pollutants, Chemical - chemistry
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2016.05.140

Polluted dredged sediments are classified as waste and cannot be re-used in civil and environmental engineering nor in agriculture, posing serious logistical, economic and environmental problems for their management. We tested co-composting of sediments (S) slightly polluted by PAHs with urban green waste (GW), as a sustainable technique to both degrade the organic pollutants and lend to sediments suitable properties to be reused as technosol. Four treatments were tested: sediments only (S), GW only (GW), 1:1 w:w S:GW (SGW1:1), and 3:1 w:w S:GW (SGW3:1) for a co-composting period of one year. The co-composting materials underwent to an initial short and moderate thermophilic phase. However, at the end of the co-composting process, SGW3:1 and SGW1:1 achieved suitable physical and chemical properties as plant substrate in terms of organic C, N and humic substances contents, electrical conductivity and bulk density. In the first six months of treatment, the PAHs concentration in SGW3:1 and SGW1:1 was reduced by 26% and 57%, respectively, reaching values below under 1mgg−1, whereas such a reduction in S alone was observed only after nine months. We concluded that co-composting with green waste can be a suitable approach for reclamation of dredged sediments opening opportunities for their use as technosol or as plant growing substrate. [Display omitted] •Co-composting with green waste (GW) was tested to reclaim dredged sediments (S).•Co-composting improved the S chemical and physical properties.•Co-composting of S and GW led to degradation of PAHs.•Co-composting end-product had suitable properties to be used as technosol.