Screening of Anticipated Impacts and Proposal Mitigations

39 Pages·2011·3.35 MB·English

by  Saquib Ejaz Hussain

ESIA of LNG Terminal, Jetty & Extraction Facility - Pakistan Gasport Limited
7 SCREENING OF ANTICIPATED
IMPACTS AND PROPOSED MITIGATIONS
Potential impacts of establishment during the n TERM = Immediate, Short, Medium or
construction and operation phases of the Long Term.
dedicated LNG Terminal on the Physical,
n EFFECT = Local (Project site only),
Biological and Socio-economic environment
Regional (beyond project area) or Strategic
have been identified and assessed in the
(related to other issues)
following sections.
Where required, mitigation measures for the
The LNG Terminal at the proposed site in Port
significant negative impacts have been
Qasim area is expected to respond to the needs
recommended.
of natural gas and LPG through import of raw
The operational phase will involve berthing of a bulk
natural gas as an environmental friendly fuel
LNG carrier, loading arm connection and pumping of
for the industrial, commercial and domestic
LNG to FSRU vessel parked alongside the berthing
consumers in Pakistan. The activities related to
facility. Subsequent processes are re-gasification and
construction and operations of this facility are
transporting of the RLNG to natural gas grid. Other
expected to have some small order
than these activities, power generation shall be made
environmental impacts on the baseline
as per demand on FSRU. Fugitive air emissions,
conditions in Port Qasim area.
operational leakages, venting of storage spheres etc.
Unlike other liquid bulk products handled at
may lead to air receptor loading.
Port Qasim, the chemical and physical
properties of LNG are such that physical 7.1- Environmental Mitigation
conveyance is limited to the primary receptor.
Goals
The product is liquid which shall be re-gasified
at the terminal for delivery to SSGC network The project is located in the Korangi Fish Harbour
system. zone. As with other growing fishery and allied
industries in such developing areas, negative impact
A qualitative assessment of each impact has
on the environment will not take place. Keeping in
been made in the impact analysis. Each of the
view the environment mitigation objective, Pakistan
impacts has been reviewed for construction and
GasPort Limited shall aim primarily to recognize the
operation phases of the LNG Terminal.
impacts and minimize or avoid such impacts on the
Mitigation measures as appropriate have been
environment. Mitigation measures have been
identified for implementation.
suggested here and Environment Management Plan
The anticipated impacts are envisaged as
has been proposed for implementation at each stage
follows:
of Project activity by having an organizational set up
to closely monitor the performance.
n NATURE = Positive (Improvement) or
Negative (Degradation)
7.1.1- Short/Near Term Goals
n MAGNITUDE = Low, Medium or High
n Planning and design/fabrication of LNG
n DURATION = Temporary or Permanent /
handling facilities to control undesirable
Cyclic (repetitive)
impacts on the environment.
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n Address the environmentally sensitive The location of LNG terminal as described in
issues such as mangrove ecology, marine chapter 3 has been carefully selected to reduce
water quality, air quality, etc. the impact on navigation and ecology. LNG
berth at the proposed location seems to be well
n Construction operation to ensure precautionary
poised in the physical scenario.
measures to avoid incidents such as spillages,
inadequate dredge disposal, mangrove While siting of the LNG berth, the onshore area and
cutting/grabbles. the pipeline alignment the following parameters
were considered:
7.1.2- Long Term Goals
n Safe distance from population.
n Long term objectives form part of the
n Proximity to berth
Environmental Management Plan aimed at creating
a general awareness among operational phase staff n Length of delivery lines to customer
and carry out periodical monitoring of quality of air network
and liquid effluents.
n Infrastructure such as roads, utilities etc.
Some of the key objectives are: n Tank foundation
n Setting up of a Monitoring and Reporting n Earthquake
System The selected site however offers more than
minimum required distance between the LNG
n Organizing a Supervisory and Monitoring
berth and mangroves, thus minimising the
Mechanism
disturbance to mangrove ecology during the
n Drawing out plans for emergency situation construction and laying of the sub-sea pipeline.
and management
7.3- Physical impacts during
n Training of personnel in safe environmental
construction & operations
practices
n Regular meetings and sessions to review 7.3.1- Noise due to LNG Terminal,
safety, environmental quality and
Pipeline and Land Facilities
emergency procedures.
7.2- Impacts at Design Stage A- Impacts during Construction Phase
LNG terminal construction and associated
7.2.1- Project Siting
activities onshore and offshore may have possible
impact on ambient noise levels. In particular,
Pakistan GasPort Limited LNG terminal is spread
works such as pile driving, dredging, drilling,
onshore and offshore. The onshore storage area is
earthworks, etc. as well as site plant such as
connected to offshore development via a sub-sea
compressors, would contribute to noise. The
pipeline. The onshore area is located in an open area
duration of the construction work is anticipated
which is presently sporadically developed. The
not to exceed over a years period.
offshore jetty and sub-sea pipeline are primarily
located in tidal waters and mangroves with no human Wind speed and direction data reveals that winds
settlements in the vicinity. However the onshore are inclined to blow from southwest. Offshore
facility has some human settlements in proximity (1.5 winds are also generated by convection changes as
km away). the land warms during the day. It is considered
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likely that there would be regular occasions when Therefore no special mitigation measures are
the prevailing wind is such that noise is directed required.
towards the land.
B- Impacts due to Operation
The acoustic effect of the creeks especially during
low water would be to echo the noise, possibly As described earlier, there are several factors that
causing a weak echo effect for sharp burst of noise would affect the potential noise from the terminal.
such as those of pile driving. However, the open Such factors include the distance from terminal to
land would help the dissipation of construction the residential areas, local acoustic, barriers to
noise. There are no notable buildings or noise, and the tolerance of the local population.
topographical features in proximity to However, distance of the residential area from the
construction sites that would provide shielding or site would be the major provider of cushion
damping effects. dampers for the noise and vibration generated due
to construction activity.
There are no developed residential areas close to
the shore area. There is no school, hospital or The operation of LNG cargo unloading, storage
library, however some human settlements mostly and re-gasification etc. are low impact activities.
comprising earthen dwellings are scattered. The Noise emissions during project operation is
source of major noise in the area is Korangi Fish expected to be much lower and generally derived
Harbour which is not of major concern. It is from facility operations such as pumps, engines,
expected that on site noise levels during other on-site machinery, and from marine vessel
construction phase may not exceed the average unloading LNG at berth.
noise of 85 dB(A) at 7.5m. Acceptable noise levels
The shore facility is not particularly noisy as there
for construction equipment may vary from 75-100
are is only pipeline juncttion and measurement
dB(A) for which the workers will be provided ear
facility. There are no continuously noisy conveyor
plugs to be worn as protective measures.
systems. The standby power generator would be
housed in its own building, and occasional use is
Mitigations:
not considered a significant noise source.
Dredging operations typically proceed for 24
The most intrusive noise source would be the
hours a day. It is not necessary to restrict dredging
terminal related traffic especially on the road
times because there is no significant or densely
outside the storage area. Traffic movements into
populated residential area in the vicinity.
and out of the storage area would continue over
Other activities during construction that can be a day hours. However, vehicles could arrive and /
source of noise and vibration would be the or depart at any time.
movement and operation of heavy construction
Sound emissions from the marine vessels would
equipment, excavation and fill operation for
mainly be generated by the operation of the
grading, pipeline cutting, welding, installation etc.
vessel's engines. The noise emissions from vessel
The noise would be confined to the local
engines are substantially dampened by their
surrounding and the impact will be of temporary
placement deep within the confines of the vessel.
nature.
The increase in noise emissions from marine
The potential changes in sound quality on other vessels using the berth is not expected to result in
local roads resulting from increased vehicle traffic significant increase in level <3dB(A).
during construction are not expected to be Additionally, sound emissions from marine
significant. The potential changes in ambient vessels will occur on an intermittent and
sound pressure levels are expected to be low. infrequent basis.
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Mitigations: due to dust and fugitive emissions.
Regular occurrence of high-level airborne dust
The sources of noise during operation of the
emission is neither reported nor recorded for the
project include vehicular movements, ships
site. The climate is dry and the surrounding land is
offloading operations, intermittent sounding of
typical of arid zone. Windy conditions prevail
horns by the ships etc. The noise emitting from
during the monsoons. As the land mass begins to
these sources will not be significantly higher than
warm up during the day, the resulting convection
the background noise level.
currents generate offshore winds starting from the
As an occupational health and safety standards the
noon hour. Dust storms are known to occur.
workers wherever necessary will be provided with
However, it is unlikely that dust generated during
earmuffs as per specifications to meet the World
construction would cause a significant nuisance
Bank guidelines. The World Bank guidelines for
impact.
ambient noise level within industrial sites
During the levelling and grading operations in the
recommend daytime and night time limits of 75dB
storage area and handling of construction
(A) and 70dB (A) respectively. The NEQ standard
materials especially materials for concrete, some
of the EPA for external noise levels is 85dB (A) at
dust will be generated. The access to the site is over
7.5 m. The IUCN report (1993) on the
an existing paved road. The movement of trucks
Environmental Review of Port Qasim area
bringing in construction materials is therefore not
suggested noise level range from 35-45 dB (A) for
expected to create significant dust emission.
small offices and 75-85dB (A) for maintenance
areas. Construction and transportation equipment (earth
movers, graders, blasting, trucks, vessels, concrete
7.3.2- Project Impact on Air Quality
batch plant, etc.) will likely generate dust and emit
combustion gases, including greenhouse gases
Construction and operation of the Project is
(GHGs), primarily carbon dioxide. Fugitive dust
expected to result in emissions into the atmosphere
and particulate matter emissions from construction
that may affect air quality. The effects on air
activities (such as clearing, grubbing, blasting, and
quality are likely to arise during construction from
similar earth-moving activities) and operational
dust generation by earthwork at onshore site and
activities (such as vehicle travel) are transient in
during operation from fugitive emissions of
nature and are dependent on many factors such as
natural gas, venting and accidental leakages in the
the moisture in the soil, the level of activity at a
components of the system
particular location, and meteorological conditions
at the time of the construction or operational
A- Impacts during Construction Phase
activities. These emissions are expected to be
Fine particulates suspended in the air can be nominal, and are expected to occur intermittently.
windblown from the site to adjacent windward Any potential for dust or particulate matter
areas. The main impact regarding fugitive generation would likely occur during periods of
emissions of dust is a nuisance effect. Certain high winds or extremely dry periods, and as such
construction activities can become major sources of are expected to be of low frequency and short
dust, for example earth-moving, drilling and duration. Given the expected low magnitude of
handling of aggregates besides operation of these emission sources, the low frequency of
construction equipment, which could generate occurrence, limited duration of occurrence, and the
fugitive emissions. However, it is envisaged most mitigation that will be applied, dust and
of the ditching and excavation would be done in particulate matter emissions from construction and
wet phase thereby minimising the impact arising operation activities are not expected to be
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substantive. emissions during project decommissioning may
also occur, although these are expected to be low.
Further, emissions from construction equipment
are another source of pollution. The air As described above, under certain conditions
contaminants emitted during construction may fugitive emissions could cause nuisance. The
include nitrogen oxides and carbon monoxide (due prevailing wind data indicate that in some
to operation of construction equipment and circumstance airborne dusts if any arising due to
vehicular traffic at the site) besides the suspended activities associated with disturbance to soil could
particulates in the form of dust. be windblown from the terminal and storage area
to inlands.
The predominant wind direction in the area is
from the west that is from the sea to the land. The The operation of LPG Terminal and storage,
airborne dust and emissions from the construction however, does not generate any dust. Another
site would be blown towards the nearby land area. source of GHGs emissions would be the trucks and
However, these would be limited to construction bowsers taking LPG supplies to consumers. As the
period. As the site is located away from urban access to site is over paved roads and truck loading
areas and human settlements which are not
bays inside the LPG storage yard will also be
developed yet, these will not create significant
paved, dust is not likely to be a problem. The traffic
adverse impacts.
generated by the operation will be normal and
within the design capacity of roads in the area.
Mitigations:
Mitigations:
The construction contract will include
requirements of dust control by frequent
The normal dust on the site should be controlled
sprinkling of water. Activities such as grading of
by regular road sweeping. Dust suppression by
aggregates which generate too much dust will not
water sprinkling is considered appropriate.
be allowed at site and will be carried out off site.
During periods when the prevailing wind ii- Emissions from the Power
direction is north-easterly and strong enough to Generators
generate airborne dust naturally, consideration
The proposed LPG Terminal would have natural
should be given to either wetting or avoiding
gas steam turbine generators as a principal
works that would worsen such effects. It is not
source of energy and diesel power as standby. In
likely that dusty conditions would occur often
case of natural gas fuel source emissions would
enough to significantly disrupt the construction
works. largely be of carbon dioxide; however diesel
generators emit a number of substances into the
B- Impacts due to Operation atmosphere including nitrogen oxides (NO ),
X
sulphur dioxide (SO), carbon monoxide (CO)
2
i- Dust and Fugitive Emissions and and particulate matter only during
emergencies. The power generating plant will
Project operations, including LNG storage tanks,
follow World Bank and EPA emission standards.
vaporisers used in regasification, demethanizer
World Bank Environmental Guidelines for
preheaters, marine vessels and vehicle traffic, will
atmospheric emission of SO and NO from
also generate fugitive emissions of natural gas, 2 X
methane, particulate matter, combustion gases and stationary combustion sources are required to be
GHGs (primarily carbon dioxide), and possibly followed. Limits given in the guidelines are as
small releases of natural gas (non-quantifiable). Air follows:
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SO:Maximum allowable increase in ground level Regionally and nationally the impact of LNG
2
concentration = 50 µg/m3(one year average). import will provide a cleaner fuel substituting for
heavy oils and will be positive, large, permanent,
NO :86 x 10-9 g/Joule heat input (fuel gas), 130 x
X
direct and long term. It will go a long way in
10-9 g/Joule heat input (when liquid fuelled)
reducing the pollution with increased substitution
Dust: When background levels of dust are high, of natural gas for other fuels.The 3.13 million tons
dust emissions from the stack should not be of imported LNG will replace 3.94 million tons of
greater than 100 mg/m3. High sulfur Furnace oil. The annual reduction in
CO will be 3.5 millions tons (29 %),NO by 26
It is ensured that the power generation plants meet 2 X
thousand tons (79 %), SO by 83 thousand tons
the standards for emissions and manufacturer's X
(99.9 %) and Particulate Matter by 6 thousand tons
specifications comply with the same.
(92 %).Additionally 25,000 tons import of diesel
Mitigations: consumed in transporting HSFO will be saved and
consequential emissions and road congestion will
No mitigation measure is required as natural gas be eased.
fired steam turbine power generators will be used.
Mitigation
iii- Fugitive Emissions of Natural Gas
Adequate and proper maintenance of all pumps,
and LPG
valves and pipelines must be ensured to limit any
The pipeline transportation and storage system fugitive natural gas and LPG emissions within
for the natural gas and LPG is to be rated for acceptable limits.
zero leakage and designed as a closed system.
Therefore, during operation of the facility there C- Air Pollution Dispersion Modelling
will be no leakages or spills of natural gas and
The project is associated with a risk due to
LPG as the latest equipment provides for suction
handling, storage and transport of LNG and LPG.
of disconnected volume. Hence, with the
Hence it was appropriate to carry out air
proposed safety equipment, the quantity of these
dispersion modelling to investigate into the impact
releases will be very small, within the NFPA and
on the ambient air quality.
US EPA specified limits and will quickly
disperse with the wind. Thus the impact of Modelling Methodology
operational releases of LPG to atmosphere is
The TANK4.0 software is employed for evaluation
considered insignificant and will not be an issue.
of emission from Liquefied Natural Gas (LNG)
Experiments made in several countries show that
storage tanks. The TANK software calculates
introduction of LPG and natural gas into the
emissions based on the equations developed by
energy matrix has contributed to a considerable
American Petroleum Institute (API) using the
reduction in pollution rates. A major positive
background information available from different
impact of national and strategic dimension is that
sources (literature survey and electronic sources).
the project, by facilitating the import of LNG and
The physical information of Floating Storage Unit
replacement of oil, wood and coal with gas as fuel
(FSU) and physical and chemical properties of the
will help reduce the air pollution and save scarce
Liquefied Natural Gas (LNG) were used for
forest resources. Therefore the impact of operation
evaluation emissions for various scenarios
of the LNG terminal on the local air quality would
enlisted for various normal and emergency
be negative. but low in magnitude and within
conditions.
acceptable limits.
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Modelling Scenarios Gaussian dispersion model AerMod software has
been used for evaluating the Ground Level
Following modelling a number of scenarios are taken
Concentrations (GLC) i.e. quantitative amount of
into consideration based upon various
emissions from the storage tanks of Liquefied
environmental, storage and decking condition:
Natural Gas (LNG) affecting the ambient air
quality has been determined. Monthly
i- Normal Scenario
Meteorological Data of Karachi Airport has been
used for the Dispersion Modelling. The
Emission of liquefied natural gas (LNG) vapours
dispersions of emissions of vapours and hazardous
(Loss of containment) at normal atmospheric
chemical as per given scenarios have been
conditions.
evaluated at distances of 100, 200, 300, 400, 500,
ii- Emergency Scenario 600, 700, 800, 900, 1000, 2000, 3000 meters from the
source towards 16 direction racially keeping north
Following emergency scenarios were considered in at 0 Degree.
the dispersion modelling:
Normal Scenario
n Scenario-1: Emission of liquefied natural gas
(LNG) vapours (Loss of containment) due to Emission of liquefied natural gas (LNG) vapours (Loss
failure of temperature control system as a of containment) at normal atmospheric conditions.
result of collision, Tsunami or other freak
Contour map shows in Figures 7.1 & 7.2 is one
weather incidence.
such case for normal scenario (please refer to
n Scenario-2: Emission of incomplete Annexure-VII for full detailed report on
combustion products of LNG (Loss of modelling). The 24-hourly average ground level
containment) in fire condition concentration of CH vapours increases from the
4
minimum level of 63.65 µg/m3 in May to
Equation
maximum level of 214.11 µg/m3in December and
2CH + 3O ----> 2CO +4HO
4 2 2 it decreases from the maximum level of 214,011
µg/m3in December to the minimum level of 63.65
n Scenario-3: Emission of combustion products
µg/m3 in May with little increase in April.
of LNG (Loss of containment) in explosion
condition (100%) Average monthly ground level concentration of
CH vapours increases from minimum level of
Equation 4
31.26µg/m3 in February to level of 47.12µg/m3 in
CH + 5O + 3(3.76)N ----> 4NO + NO + CO +
4 2 2 X 2 2 June. Then it starts increasing and reaches the
2HO
2 maximum level of 13.51µg/m3 in the November.
From November, it again decreases to the
Modelling Applications
minimum level of 31.26µg/m3 in February. Also
the direction of dispersion is SW from Nov-Feb
The TANKS 4.0 software was used for estimating
and NE from Mar-Oct. In the month of February
the emissions. The emissions were calculated
direction of dispersion is both in SE and SW.
according to EPA's AP-42. The information
requisite for the use of software was provided and
Emergency Scenario 1
emissions for the storage tank containing liquid
LNG calculated. The software has evaluated the Emission of liquefied natural gas (LNG) vapours (Loss
emission related the above scenarios assumed for of containment) due to failure of temperature control
modelling. These emissions are summarized in the system in result of some collision, Tsunami or other
following table: freak weather incidence.
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The colour contour graphical and spatial Equation
representation of one such case of the dispersion of
2CH + 3O ---> 2CO + 4HO
4 2 2
gaseous pollutants emitted for emergency
scenarios of failure of temperature control system The colour contour graphical and spatial
representations of the dispersion of gaseous
due to collision, Tsunami or other freak weather
pollutants emitted emergency scenarios at
incidence are shown in Figure-7.3 and 7.4 (refer to
incomplete combustion are shown in Figures 7.5 &
Annexure-VII for extensive details).
7.6 (please refer to Annexure-VII for full details).
Above contour maps show that for emergency
Table 7.1: Nature of Emissions in Scenarios
Scenario Emission in gm/sec Contents
Table 7.2: 24-hourly Conc. of CH in Normal
4
Scenario
Normal 2.0636289 CH4 Vapors
Emergency-1 1196.316494 CH4 Vapors Months Concentration (µ/m3)
Emergency-2 67.03 CO Vapors Jan 139.04
Feb 120.13
Emergency-3 198.10739 NOX Vapors Mar 101.22
Apr 107.73
May 63.65
Above contour map shows on such emergency
Jun 80.51
scenario, failure of temperature control system due Jul 107.62
Aug 121.01
to collision, Tsunami or other freak weather
Sep 124.81
incidence, the 24-hourly average ground level
Oct 123.60
concentration of CH vapours increases from the Nov 200.72
4
Dec 214.11
minimum level of 38,066.87 µg/m3 in May to
maximum level of 128,038.92 µg/m3 in December
Table 7.3: Monthly Conc. of CH in Normal
4
and it decreases from the maximum level of Scenario
128,038.92 µg/m3 in December to the minimum Months Concentration (µ/m3)
level of 38,066.87 µg/m3 May with exceptional Jan 42.87
little increase in April. Feb 31.26
Mar 59.33
Average monthly ground level concentration of Apr 55.75
May 50.94
CH vapours decreases from maximum level of
4
Jun 47.12
67,880.64µg/m3in November to minimum level of
Jul 49.57
18,696.45µg/m3in February. With little increase to Aug 57.84
Sep 72.16
a level of 35,483.22µg/m3, average monthly
Oct 63.69
concentration decreases to the level of
Nov 113.51
28,181.20µg/m3 in June. From July it again Dec 96.38
increases to the maximum level of 67,880.64µg/m3
in November. scenario (incomplete combustion), the 24-hourly
average ground level concentration of CO
Also the direction of dispersion is SW from Nov-
increases from the minimum level of 2,132.50
Feb and NE from Mar-Oct. In the month of
µg/m3in May to maximum level of 7,172.74 µg/m3
February direction of dispersion is both in SE and
in December and it decreases from the maximum
SW.
level of 7,172.74 µg/m3 in December to the
minimum level of 2,132.50 µg/m3in May with little
Emergency Scenarios 2 and 3
increase in April.
Emission of incomplete combustion products of LNG
Average monthly ground level concentration of
(Loss of containment) at fire condition
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