The nature and extent
of the environmental impacts associated with the construction and operation
phases of the Project are summarised below.
For installation of the FGD plants, two above ground
oil storage tanks (No. 4 and No. 5 Light Oil Tanks) with associated pipelines
and one oil separation sump are to be demolished to provide space for
installation of the FGD plants.
Contamination Assessment Plan (CAP) has been prepared and approved by
the EPD in November 2005 and site investigation (SI) was conducted in the area
adjacent to the tanks and oil separation sump.
The SI results indicated that total petroleum hydrocarbon (TPH) was
detected at one soil samples and five groundwater samples exceeding Dutch B
guideline for mineral oil. Results of
the SI and recommendations have been reported in the Contamination Assessment
Report (CAR) and the Remedial Action Plan (RAP) (see Annex of the EIA Report).
Therefore, remedial measures and procedure for TPH contamination are
recommended in the RAP.
With the implementation of the remedial measures in
RAP, no land contamination would be anticipated.
Dust nuisance is the
key concern during the construction of the Project. Demolition of the existing Nos 4 and 5 Light
Oil tanks with each of 250m3 storage capacity, civil works of the
retrofitting of FGD Plants to two existing 350MW coal-fired Units L4 & L5
are the major construction works of the Project. Due to small scale of the Project and with
the implementation of the recommended dust suppression measures stated in the Air Pollution Control (Construction Dust)
Regulation, no dust impact is anticipated.
In addition, only limited number of diesel-driven equipment will be
operated on site, therefore, impact from construction equipment is not
expected.
For the operational air quality assessment, the re-assessment of the previous wind tunnel modelling data has confirmed that the FGD retrofit project at units L4 and L5 of the Lamma Power Station will lead to significant reductions of the worst-case hourly SO2 concentrations for most ASRs throughout the area studied.
Other environmental benefit of the FGD retrofit includes the reduction of the particulate matter (PM) emissions resulted from the wet scrubbing process of the FGD plant.
The NOx emissions will not be reduced nor
increased by the project, however changing of the stack exhaust parameters may
result in a re-distribution of NOx in the vicinity of the power
station. The cumulative concentrations of NO2 after the retrofit
have been estimated and their AQO compliance demonstrated for at all ASR
locations.
Based on the impact assessment, the current
monitoring programme for the Lamma Power Station can cover the Project and no
additional EM&A measures are required.
Construction runoff and sewage effluents generated from the workforce are the potential sources of water quality impacts during construction. Assessment results indicate that no unacceptable water quality impacts will arise from the construction activities provided that the recommended mitigation measures are implemented.
Potential source of impacts to water
quality from the operation of the FGD plants are as a result of filtrate
generated from the dewatering of gypsum slurry.
Since the existing WWTP has spare capacity to cater for the additional
wastewater produced from the proposed retrofit project, it is expected that
effluent from the WWTP to the Ash Lagoon will meet the requirements in the WPCO
licence for the
Based on the impact assessment, the current
monitoring programme for the Lamma Power Station can cover the Project and no
additional EM&A measures are required.
The key potential impacts during the construction phase are related to management of demolition materials, excavated materials and construction waste. With the implementation of the mitigation measures recommended, the potential environmental impacts arising from storage, handling, collection, transport and disposal of wastes should be able to meet the criteria specified in the EIAO-TM. Hence, no unacceptable waste management impact is anticipated.
All the additional gypsum (about 46,000
tonnes per year) and sludge (about 1,200 tonnes per year) will be generated and
reused in Hong Kong and/or in Mainland
The proposed Project is in small scale. Additionally, in the view that the residential developments are shielded from construction noise to varying degrees by the intervening hill (Kam Lo Hom) and the existing plants, and considerable separation distance between the NSR and the Project, the noise generated during the construction stage is not expected to be a concern. . However, in order to ensure that the construction noise levels at the NSRs controlled within the relevant criteria, good site practice and noise management is recommended during the construction phase.
Based on a worst-case scenario, the operational noise levels due to additional equipment will comply with the noise criterion and will have insignificant contribution to the cumulative operational noise of the Lamma Power Station. Therefore, the plant noise associated with the retrofit plant is not expected to give rise to unacceptable environmental impacts.
In addition, most of the noise sources associated with the retrofit project will be housed within individual acoustic enclosure to minimise the noise impact to the environment.
In view of the anticipated insignificant noise impact in both construction and operational phases, additional noise monitoring work for this Project is considered not necessary.
The proposed retrofit works will not have any
negative impact on the surrounding landscape, and will have a very low
visibility for the following reasons:
· The location for the proposed
retrofit works is within a large existing industrial facility;
· There will be no impacts on the
surrounding landscape area;
· The new infrastructure will be
finished to complement the existing industrial surroundings;
· The relatively small scale of the
retrofit works within the existing facility means that the works will have a
low visibility.