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The second approach is to plan maintenance through
periodic dredging operations around the dock of Cala
Principale. In both cases, particular attention is required 4. “Red”– These sediments are highly contaminated and
to protect the Posidonia oceanica meadow and marine
life during dredging by using turbidity curtains.
The four classes considered in Figure 3 and Table 1 are
better described as follows:
1. “Light green”- this material can be beneficially used
for beach nourishment or other intervention along
the coast, in direct contact with the seawater as no
contaminants are found and all concentration are
below the thresholds indicated for quality standards
of marine coastal water.
2. “Dark green” - These sediments have concentration
levels higher than the limit of intervention, but lower three possible types of interventions on the territory
than the thresholds of private public or residential
sites. Seabed dredging is not mandatory, but in case
of removal they should not be in direct contact with
the seawater.
3. “Yellow” - These sediments have concentration
values between private, public or residential sites
and industrial areas. They should be dredged
FIGURE 8 :JOLTH[PJÅV^KPHNYHT^OPJOKLZJYPILZ[OLWVZZPISLVW[PVUZVMJVU[HTPUH[PVU Conclusions
subsequent dredging volume and management scenarios
urgently and disposed within Confined Disposal Research & development
Facilities (CDF).
concentration values are above the limit for dangerous
waste. Immediate removal should take place to avoid
transfer of contamination from the seabed to the water
column, flora and fauna. Subsequent disposal should
be guaranteed according to current legislation.
Due to the low level of contamination determined in the
present study (Table 1) and the volume to be dredged
(Figure 6) the overall cost for interventions is expected
to be between ~50.000 € and ~1 Ml €, depending on
the extent of treatment to be adopted (soil washing,
dewatering, land farming, desalination). The results
of this preliminary work allowed ENEA to propose
(Figure 9): Sports facilities; Coastal restoration; Harbour
(scenarios A, B, C of Figure 8), as we assumed that
the large part of dredged material will be classified
as dark green sediment. Sediment sale has not been
considered due to the heterogeneity of physical and
chemical characteristics.
Handling, treatment and reuse
of sediments are topics that
encompass many disciplines, which
are necessary for the successful
implementation of the dredging
operations aimed at a beneficial
reuse of sedimentary natural
resource. Therefore, the regulatory
framework is very complex. The
Italian legislation is continuously
evolving, but still does not consider
risk analysis as a decision tool
for dredging the contaminated
sediment. Law no. 27 of 24th March
2012 sets out the criteria for the
classification of sediments and
their possible reuse or disposal.
These changes and the Ministerial
Decree of 7th November 2008 offer
a more comprehensive regulatory
45EAI Energia, Ambiente e Innovazione 4/2015