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Research & development
Results
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The implementation of the conceptual model allowed to
identify four potential sources of contamination, facing
the harbour basin: the gas station in front of the quay, the
Florio industries where tuna processing was performed,
the Camperia’s building (where boats storage and
maintenance was performed and, finally, a discharge
of untreated wastewater. A flow diagram of conceptual
model for contamination is reported in Figure 6.
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The characterisation of superficial sediments allowed
to determine both physical and chemical properties
of particles. The grain size revealed a percentage of silt
and clay of about 1% and a D50 of approximately 0,215
mm (Figure 7). The analytical tests detected a moderate
exceedance of limits, indicated in columns A and B of
Annex 5 to Part IV of Legislative Decree no. 152/2006,
FIGURE 6 Conceptual model of contamination for sediments
within Favignana’s Harbour
42 EAI Energia, Ambiente e Innovazione 4/2015
FIGURE 7 Cumulative grain size determined for each
of the all 4 samples
for Cadmium, Arsenic, Lead, Tin, IPA and TBT. The
exceedances have led to classify sediments with “yellow”
color, i.e. with values of analytical tests that fall within the
90% limit imposed by the column 5 of Annex B to Part IV of
Legislative Decree no. 152/2006 (Table 1) [15].
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In the present work, the list of technologies considered
are biological, physical-chemical and electro-thermal.
The most common know-how is organised following the
approach proposed by Bortone and Palumbo (2007), in
order to identify the Best Available Technologies (BAT)
for each different treatment approach. A summary of
results is presented in Table 2, which shows the range of
costs in €/m3 and possible investment costs.
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A preliminary project was prepared in order to allow
the local authorities to allocate the necessary budget
for dredging operations within Favignana’s Harbor
according to the procedures indicated by the national
legislation (e.g. characterisation of sediment up to 1-2 m
of depth).The project considered all phases of sediment
removal and management, and particular attention was
given to the presence of protected marine species,
such as Posidonia oceanica meadow. Therefore, two
options were identified, considering different volume