ERM conducted a walkthrough of the
proposed project area on 4 October 2005 and identified potential areas where
fuel storage and transmission facilities were located, as follows:
·
Two
aboveground fuel storage tanks, aboveground steel structures of 250 m3
underlain and surrounded with concrete bunding. Visual inspection of the concrete bunding showed no evidence
of oil leakage or spillage;
·
Fuel
pipelines connecting between the fuel tanks and the fuel oil transmission pump
houses. The pipes are located in
underground trenches. Initial
visual inspection of the areas showed no evidence of oil leakage or spillage;
·
Stormwater
collection and oil separation sump.
The reinforced concrete tanks were located in ground. Visual inspection of the area showed no
evidence of oil leakage;
Locations of
these facilities are presented in site layout map (Figure 2.1a)
attached. The Nos. 4 & 5 Light Oil Tanks were designed
according to the Code of Practice issued by the Building Authority. The oil tanks foundations were made of
concrete raft footing, the surrounding reinforced-concrete slabs with bund
walls constructed of reinforced concrete.
The bund walls were designed to provide containment volumes of not less
than the maximum operating capacity of the oil tank and the containment was
fitted with drain channels connecting to a sump pit, where the oil/oily drain
will be further diverted (operated by manual valve) to the oil separator. An oil detector has been installed to
detect any oil spillage and alarm will be generated at the control room for
notification and further action.
The oil separator was constructed with reinforced concrete.
Visual
inspection of the tanks, pipeline trenches and oil separator areas identified
no apparent evidence of oil staining on the concrete pavement or in the
drainage trenches. HEC confirmed
that no major spillage/leakage of oils or chemicals occurred at the Site since
the commissioning of the tanks in 1990.
Minor spills
within the bund areas during maintenance were reportedly collected and then
further processed in the oil separator.
No soil and
groundwater contamination studies have been conducted at the Site.
Based on the review of site information
and the walkthrough the potential sources of soil and groundwater contamination
from the Nos. 4 & 5
Light Oil Tanks and oil separator included the oil storage, transmission facilities and oil separator sump
as described in Section 2.1.
The facilities may be considered potential sources of land contamination
due to the following reasons, but not limited to:
·
Leakage
and/or spillage from the oil tanks to the underlying soil and groundwater;
·
Spillage of
oils during the filling of the tanks which may enter the surrounding areas; and
·
Leakage from
the in-ground oil separator to the surrounding soil and groundwater.
The likely
contaminants associated with the fuel storage facilities include, petroleum
hydrocarbons (TPH), simple aromatic hydrocarbons (BTEX) and polycyclic aromatic
hydrocarbons (PAHs).