Internship Report

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PREPARED BY:
NAME : Ammara Haider
INTERNEE NO. : 117
DEPARTMENT : Technical Services
SUBMITTED TO:
NAME : Syed Mahmood Mehdi
Zuhair Sadiq
DESIGNATION : Process Engineers
DEPARTMENT : TECHNICAL SERVICES

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IN THE NAME OF
ALLAH
The Most Gracious,
The Most Merciful.
Whose Help We Solicit

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DEDICATED TO
My loving Parents, their
un-returnable patience,
prayers & guidance to
bring me to this position.

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ACKNOWLEDGEMENT
All praise to ALMIGHTY ALLAH, who provided me with the
strength to accomplish this orientation report. All respects are
for His HOLY PROPHET (PBUH), whose teachings are true
source of knowledge & guidance for whole mankind.
Before anybody else I thank my Parents who have always
been a source of moral support, driving force behind
whatever I do. I am indebted to my trainers Zuhair Sadiq
(Process Engineer) and Syed Mahmood Mehdi
(Process Engineer) for their worthy discussions,
encouragement, technical discussions, inspiring guidance,
remarkable suggestions, keen interest, constructive criticism
& friendly discussions which enabled me to complete this
report. They spared a lot of precious time in advising &
helping me in writing this report.
I am also thankful to Mrs. Khalida Mudassir (In charge
Library) for her cooperation in search of material.
Internee
Ammara Haider

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PREFACE
Today faced with increased rivalry among the
major competitors, it is mandatory for an
organization to engage in quality practices,
primarily to maintain its existence in competitive
environment and secondary to gain competitive
advantage over its competitors. One could argue
that it is virtually impossible for organizations to
function effectively without quality practices. The
quality practices not only improve the corporate
value but also canalize the energy of the people
working there. In most of the contemporary
organizations, regardless of the strong financial
position, substantial growths are not achieved
due to poor quality practices.

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TABLE OF CONTENTS
1. General Information …………………………………………………………………………7
2. Utilities Introduction………………………………………………………………………….9
3. Effluent Collection, Treatment and Disposal System…………………………….13
4. Additional Assignments……………………………………………………………………..22
5. Environmental Assessment Report on DHDS Installation……………………….31
6. P&ID………………………………………………………………………………………………..36

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GENERAL INFORMATION
Introduction:
Pak Arab Refinery Limited:
(A national organization with an internal presence)
PARCO is a joint venture between Government of Pakistan and Abu Dhabi. The MCR
(Mid-Country Refinery) was established in 2000 but the organization is about thirty
years old. Before the MCR the organization only served to pump HSD to various part
of the country via pipelines from Karachi. To fulfill the needs of the country a refinery
needed to be established. Thus the MCR was established.
For the PARCO, MCR crude oil is being imported from Middle east i.e. Arabian Light,
Upper Zakum, and Murban. Local crude oil and local condensate are also used. The
crude is being transported through Karachi-Mahmood kot pipeline. In 2005, white oil
pipeline was commissioned from Karachi to Mahmood kot to transport diesel.
Process Units with their Design Capacities:
“Capacity is the minimum rate of output for a facility”
The Refinery complex includes 11 onsite units’ process units besides numerous off
site / utilities units and other permanent facilities with 51 tanks to store the Crude oil,
intermediate feeds stocks and finished products.
S. No. Unit Code Units BPSD
1 100 Crude Distillation 100,000
2 110 Vacuum Distillation 42,800
3 130 Visbreaker 15,560
4 200 Naphtha Hydrotreater 25,400
5 284 Dieselmax * 22,450
6 300
CCR Platformer &
Cyclemax CCR
16,350
1,000 lb/hr (454 kg/hr)
7 411 Gas Concentration
Liquid: 22,050
Gas: 12,548 Nm3
/hr
8 801 Kerosene Merox 20,000
9 802 LPG Merox 4,500
10 810 Amine Treating
F.G: 8,618 Nm3
/hr
SWS: 76 SM3
/hr
11 820 Sulphur Recovery 115 MTPD
* Dieselmax Process Unit (Mild Hydrocracking with Thermal Cracking) for maximizing
HSD production at Relatively Low cost.

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PARCO MCR Products:
The products of Refinery are as follows:
1) Fuel Gas for Refinery Use
2) LPG for cooking burners
3) Motor Gasoline for cars
4) HOBC for cars
5) JP-1 & JP-4 for Air Fighters
6) Jet A-1 & A-4 for Air Crafts
7) Kerosene for Domestic Use
8) HSD for buses and trucks
9) LDO for conventional engine tube wells
10) Fuel oil for power plants
11) Sulfur for fertilizer plants
Utilities:
The utilities at MCR consist of the following units.
S. No. Unit No. Unit Name
1 900 Chemical Handling System
2 910 Plant And Instrument Air System
3 915 Flare System
4 920 Fuel Gas and Fuel Oil System
6 925 Water System
7 926 Fire Protection System
9 940 Steam System
8 930 ETP
Briefly discussion of all these units is as follows.
1. Chemical Handling System (Unit # 900)
Unit 900 is composed of the following systems.
• 25 Be Caustic Soda Handling System
• 98 % Sulfuric Acid Handling System
In Caustic system, 50 wt % caustic unloading pumps shall transfer the caustic
to 25 Be caustic tanks which have demineralized water in advance to dilute 50
wt % caustic to 25 Be caustic. The 50 wt % caustic unloading pumps shall
circulate the caustic solution for mixing.25 Be caustic is transferred to each
user by 25 Be caustic pump which is running normally.

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Two of caustic tanks cover approximately 21 days of normal demand of users.
In Sulfuric Acid system, sulfuric acid (98 wt %) is pumped to a sulfuric acid vessel.
The sizing of the sulfuric acid vessel is based on demand from various systems.
The sulfuric acid vessel covers approximately one month of normal demand of users.
2. Plant And Instrument Air (Unit # 910)
Unit 910 is composed of the following systems:
• Air Compressors Package section
• Air Dryer Package Section
Plant and Instrument Air is supplied by the two equal size centrifugal
compressors, one operating and one spare. The compressor capacity is
determined in such a way that one compressor can supply the air demand at
normal operation. In the case of Diesel max Regeneration Operation, both
compressors will be run in parallel. One compressor is motor driven, and the
other one steam turbine driven.
Plant and Instrument Air System will include adequate facilities to provide
required quantities of instrument air and plant air at uses.
3. Flare System (Unit # 915)
The Flare System is designed to handle the normal gas release and the
emergency gas and liquid release from the refinery. This system consists of
the Main flare System and acid Gas Flare System.
i) Main flare System
The capacity of Main Flare System is 950 ton/hr and the relieving
vapors. It is provided to construct relief valves , discharge and normal
process vents and the relieving vapors and liquid are collected to main
flare system from Crude Distillation Unit , Vacuum Distillation Unit ,
GasCon , Visbreaking Unit , Diesel max Unit , Plat forming , Plat forming
CCR Section , Naphtha Hydrotreating Unit, Kero Merox ,LPG Merox , Fuel
Gas System , LPG Sphere Tanks, Boiler Section in Utility Facilities.
ii) Acid Gas Flare System
The capacity of Acid gas Flare is 48.6 ton/hr ans is provided for off gas
containing hydrogen sulfide. Relieving Vapors and liquid to Acid gas
Flare System are collected from Diesel max, Amine Treating Unit, Sulfur
Recovery Unit, Effluent Treatment & Disposal System.

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4. Fuel Oil And Fuel Gas System (Unit # 920)
This Unit covers the operation of the Fuel gas Section in the Fuel Oil and Fuel
Gas System. The refinery, in which the Fuel Oil and Fuel Gas system installed,
is a large consumer of thermal energy in the form of liquid and gaseous fuel.
In addition of processing the feedstock, the refinery is also the producer of its
own fuels. The fuels are gathered and redistributed by two systems.
• Fuel Oil System
• Fuel Gas System
The fuel gas system is designed to collect process unit off gas, natural gas and
vaporized LPG. All sources of gas are routed to knockout drum which provides
liquid knockout and mixing.
One LPG vaporizer is provided to make fuel gas and to dispose of off- spec or
excess LPG. Off – spec LPG is produced at start up of Gas Concentration Init,
LPG Merox Unit and CCR Plat forming Unit and sent to LPG Vaporizer.
The priority of fuel gas sources is as follows:
Normal Operation: Refinery OFF Gas
Primary Makeup : Natural Gas
Secondary Makeup: On – Spec LPG vaporized in LPG Vaporizer
5. Water System (Unit # 925 )
This Unit composed of the following systems.
• Well Pumps Section
• Raw Water and Plant Water Section
• Potable Water Section
• Cooling Water Section
i) Raw Water
Water is readily available in the area from shallow wells with a capacity
of about 100 m3/hr per well. A total of six wells are provided, although
four wells are sufficient to meet the normal raw water requirements.
Water from wells is pumped up normally to Raw Water Tank and for fire
water up to Fire Water Tank by well pumps .Raw Water Tanks serve as
a secondary source of fire water, raw water stored in the water tanks is
pumped to the following users by the raw water supply pumps.
• Plant Water Make-up
• Make up of Potable Water
• Sulfur Solidification (as cooling medium)

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ii) Plant Water
Raw water is pumped directly from the raw water supply pumps via back
flow preventer refinery plant users. At downstream of the back flow
preventer service changes its name as plant water. Plant water is mainly
used mainly of Boiler Make up Water Treating System feed, Cooling
Water Make up utility hose stations and other miscellaneous users.
iii) Potable Water
Raw water is treated by the potable water filter system and potable
water chlorination system. The treated water is stored in a potable water
tank as potable water. Potable water is pumped to users by a refinery
potable water pump.
iv) Cooling Water
Cooling water is supplied from an evaporative cooling tower circulation
system. Cooling water is pumped to the various users by the cooling
water circulation pumps and returned to the cooling tower from the
cooling water circulation system has side stream filter system. Chemical
feed System and Chlorination System.
6. SAFETY AND FIRE FIGHTING SYSTEM (Unit # 926)
Fire water protection system consists of fire water distribution system, foam
extinguishing system , potable nozzles , fire extinguishers , tools and
accessories etc. The fire protection system intends to prevent fires, as well as
to minimize control, or extinguish fires already burning.
Water to be used for fire protection system is well water from well water from
well water pumps. Well water will be stored at the Fire Water Storage Tank
and at the Raw Water Tanks.
The fire water tank is a fixed roof tank wills the capacity 13626 m3 based on
the requirement of the fire water demand at the rate of 2271 m3/hr for six
hours continuous fire fighting operation.
The two water tanks are also fixed roof tanks with a capacity of each tank
4542 m3 based on requirement of fire water demand at the rate of 2271
m3/hr for additional four hours continuous fire fighting operation when the fire
water tank is empty.

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7. Steam, Feed Water And Condensate Handling System (Unit # 940)
This unit is composed of the following systems:
• Boiler Make up water Treating section
• Condensate recovery System
• Deaerator section
• Boiler Section
• Steam Letdown Section
The main purpose of the unit is to generate and distribute steam to the plant
users. The system consists of three levels of HP Steam, MP Steam and LP
Steam, and each steam level condensate is recovered as much as possible.
This system will include all facilities to provide steam at the required
temperature and pressure, except the process steam generators.
8. Effluent Collection, Treatment And Disposal System (Unit # 930)
Effluent Collection, treatment and Disposal Effluent Collection, treatment and
Disposal System (Unit 930) of PARCO is designed to collect and treat the
effluent water from refinery to be within Stipulated Effluent Units for treated
water. The collection system collects storm water (fire water) from areas
where oil contamination is likely to be present and process utility waste water
through piping system and sends it to WTP for its treatment. In rainy or fire
situation when the quantity of Effluent water will exceed its capacity, it is led
to diversion tank and the system also collects aromatics waste, slop oils is to
be recovered to the refinery slop oil tank.
The system is composed of following major systems
• Clean water sewer system
• Oily water collection system
• Slop oil recovery system
• Spent caustic neutralization system
• Closed aromatics waste system
• Waste water treatment system
• Oily sludge handling system
• Bio-sludge handling system
• Sanitary waste treatment system
i) Clean water sewer system:
This was a simple and easy operation. All the storm or rain water having
no oil contamination is collected in an open basin without any treatment.
Nor unit is installed for it neither any chemical is added. Clean water
without any contamination in open basin evaporates to atmosphere by
drying of sunshine

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ii) Oily water collection system:
This system collects the storm water which is oil contaminated and has
varying amounts of BOD, COD, S.S, oil and grease etc. It receives
desalter effluent, skipped sour water, process effluent water and oily
storm water are directed towards the lift station of WTP (930-ME2) is
collected between and gas flare area and WTP area.
In case of excess effluent, the third section is turned on operation using
three process high flow pumps (930-P2A/B/C) which transfer the excess
to diversion tank (930-TK1). Pumps are automatically controlled.
Diversion tank (930-TK1) is open roof tank located between acid flare
area and WTP area used to collect excess effluent. The effluent stored in
diversion tank is sent back to waste water lift station by gravity.
The leaded oily storm water from tank loading area is transferred to tanks
930-ME6A or 930 ME6B. It is, then sent to lead waste tank 930-TK4. The
lower layer of water is sent to oily water treatment system through
nozzle. While the accumulating oil is carried to leaded slop tank (945-
TK49).
Oily storm water is stored in tank dyke area and pumps are led to tank
age waste water lift station (930-ME 9 A/B).
The Process waste water lift station (930-ME2) consists of bar stream
(930-ME80) and belt type simmer (930-ME81) which are provided at its
inlet section continuously operating and remaining large floating and
suspended materials and oil in effluent water. Low flow tank-age lift
pumps installed at (930-ME 9A/b) starts or stops pumping the effluent to
diversion tank skimmed oil removed using belt type simmer is drained to
skimming sumps from where it is transferred to slop oil holding tanks
(930-TK6A/B) using skimming pumps while the oily water is pumped to
API oil/water separator (930-ME3A/B).
The processes of important units in operation for the removal of oil from
water in oily water collection system are described below:
• API Oil/ Water Separator (930-Me3-A/B)
All the oily waste water screams from refinery are pumped to API
Oil/Water separator basins for removal and recovery of oil and
sludge. The two gravity type API Oil/ Water separators have design
capacity of 170 m3/hr each.
They have inlet and outlet weirs to adjust level with inlet weir at
higher level from outlet weir separated by baffles. They all are
manually adjusted to enable surface oil to be skimmed off easily.

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Effluent is send to separating channel via baffles and distributes the
oil and water mixture over cross-sectional area of flow. At the same
time as the surface oil is distributed, the flow velocity dissipates to
enable greater separation.
API oil/water separator is also filled with chain driven scrapper which
collects the oily sludge to sludge slowing sumps at the basin floor. It
is automatically and manually controlled. Sludge valves are installed
to drain the sludge in API sludge sump. Water recovered from oily
sludge treatment Process and discharged from Oil sludge Thickener
also enters API fore bay.
A slotted pipe type skimmer is installed just before the outlet section
of API Oil/Water Separator unit which collects floating oil and drain it
to API skimmer oil sump. Recovered oil from these sumps is
transferred to tank through pumps.
Effluent water from API oil/water separator is collected at Outlet
section of separator basin and pumped to Equalization Tank.
Effluent water from API Oil/Water Separator is collected at Outlet
section of separator basin and pumped to Equalization Tank.
API scraper are chain driven devices which uses planks which
continuously circulate along the top of water in one direction and
back along the bottom of tank in one direction. It scrapes oil off the
water surface and scrapes sludge along bottom of tank into sludge
sump. API skimmer is installed in separation section of each basin
rotate and collects oil off water surface and discharges it into basin
and sump.
Air driven diaphragm type pump are used to pump sludge from API
sludge sump to oily sludge setting tank. API skimmed transfer oil
from sump to be reprocessed in refinery. Whereas API effluent
pumps, pump water from API Effluent Sump to Equalization tank.
• Dissolved Air Floating Unit (930-Me4-C/D)
The DAF feed pumps the waste water from Equalization Tank to DAF
Flash Mixing Basin. The DAF Flash Mixing Basin gets the regulated
effluent controlled by DAF feed valves. Effluent under control
conditions is mixed and equalized into Flash Mixing Basin. Flash
Mixing Basin has three compartments. First two compartments have
mixers with vertical shafts and propeller for mixing while third
compartment is stilling chamber. These mixers provide mixing of
waste water and chemicals prior to their entry to DAF Basin.

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Effluent first flows into first compartments where and or vase are
closed at sufficient rate using control pumps to maintain the pH
range between 6-9. pH sensors are installed to give control pH
process readings and base are present in day storage tanks for
continuous supply. After pH adjustment, effluent moves to the
second compartment. Both compartments are separated by baffles.
Coagulant ferric chloride is added to assist the formation of froes in
waste water before waste water enters DAF basins. Speed of
flocculator is adjusted. As effluent moves to the stilling chamber,
DAF polymer is added to promote the formation and settling of
flocks.
The effluent is then closed to Flash mixer basins having baffles which
equalizes and evenly distribute the flow across the width of both
chambers. It is also filled with flocculator having normally adjusted
speed. The effluent flows over and under baffles and enters DAF
Basins.
Now, after chemical close and formation of flocks, effluent in DAF
inlet baffle is injected with air saturated recycle water. It actually
works on dissolved air floatation principle. The compressed air is
supplied from refinery plant air system. Flow is introduced through
nozzles. Nozzles are positioned to ensure optimum contact occurs
between micro-bubbles of air and morning flock particles air bubbles
capture the flock particles and float on the surface.
A portion of treated water resulting from DAF process is pumped
back into DAF water pressure vessels. Water is vessels becomes
saturated with compressed air under control conditions and is
injected back to DAF basins.
DAF basins have simmer to remove the floating flocks forming a
blanket surface and a scraper at bottom for the removal of settled
sludge. Skimmers operate at adjustable speed to remove suspended
flocks from water surface while scraper scraps off the bottom sludge.
Skimmer scrape the flocks into DAF sludge troughs while scrapers
discharge into DAF sludge sump from here, oily sludge is pumped to
oily sludge setting tank and effluent flows to Biological Aeration
Basin.
• Biological Aeration Basins (930-Me5a/B)
The effluent from DAF basins flows to Biological Aeration
basin where organic matter is reduced while minimizing BOD
to the acceptable limit by supplying air or oxygen into water
which results in aeration. Air blowers are installed to ensure
sufficient aeration by ensuring homogenous mixing to

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achieve and maintain the DO level of 2 mg/L. Oxygen supply
is manually controlled so the flow of air in the basin is
sufficient for oxygenation and BOD5 reduction to occur.
The basic principle of biological treatment operates here where
bacteria’s under the supply of oxygen and nutrients i.e Di-ammonium
Phosphate (DAP) consumes organic matter for synthesis and new
bacterial cell synthesis. Energy produced is utilized by bacteria for
their working.
New biomass accumulation results in needing of more oxygen and
nutrients. This reduces the efficiency of process and thus some of
the waste is to be removed.
Since this is an aerobic process, oxygen requirements are high and
cannot be fulfilled with the DO of incoming waste water. That’s why
oxygen is continuously supplied from the air blown through the
waste water.
To increase the concentration and formation of activated sludge,
flocks produced in short interval of time are removed from waste
water through sedimentation and returned to influent of activation
unit wile excess flocks are wasted.
Since free living bacteria’s are present in returned activated sludge,
they greatly enhance the efficiency. Due to recycling problem of odor
is avoided. An estimated may increase the oxygen consumption and
cost of operation.
The sludge in excess must be withdrawn from the basins to maintain
the treatment process.
The influent into the Aerobic Basins is also regulated. Activated
sludge may be overloaded by introduction of strong waste water
producing odor and poor separation of suspended solids from mixed
liquor. This also results in increase in oxygen Demand. Sufficient air
must be supplied at influent source, less of amount sludge is
required and washing excess sludge to accommodate fresh sludge
and re-aerating the returned sludge can overcome the problem of
overloading sludge.
Activated sludge plant operating removes 85~90% of BOD, similar
range of suspended solids and 90-98% of bacteria.
The efficiency of purification of effluent depends upon either
oxidation of organic matter with bacteria and separation of flocks
from the purified effluent water. For continuous removal of organic
matter, purification efficiency is greater, lower F/M ratio.

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After formation of flocks of organic matter and purification of effluent
through proper aeration and biological activity, effluent is sent for
further treatment o clarifiers.
• Clarifiers (930-Me27a/B)
Flocs formed on the surface of mixed Liquor are separated
by settling procedure in clarifier unit also known as
secondary settling tank. Activated sludge from aerobic
basins tends to flocculate under specific gravity near the
water. The ability to settle the flocs depend upon many
factors i.e. presence of industrial waste, DO content,
aeration mode, presence of micro-organisms, temperature
etc. the proper operation of clarifiers. Clarifiers are installed
for two important functions.
• Purification of waste water
• Thickening of the recycled sludge
Design of clarifier is also very important for its efficient performance
other than the effluent flow rate and quality of bio-sludge from the
bio-treatment system.
Depth of structure is one of the important features. It must be
sufficient to give sludge required time to thicker and avoid
fluctuations while settling. Usually a3 m min height tank with small
diameter is recommended.
Its efficiency also depends upon the recycling rate of suspended
solids. Retention time should be adequate for settling.
If retention time is less, vol of sludge stored will be large near the
collecting weirs and the quality deteriorates. Anaerobic conditions
prevail and clarification process is disturbed.
Shape is another parameter for the effectiveness of clarifier. Shape
of clarifier should be vertical flow settling with highly slopping bottom
gives best results. They are often equipped with scrapers pushing
the sludge into ____ from where it is recovered for recycling and
removal of excess fraction. While skimmer is present to scrape the
floating scum from the surface of clarifier and discharge into clarifiers
skimming tanks. These are clarifier sludge recycling pumps too that
pump sludge drawn from the bottom of clarifier back into inlet of
biological Aeration Basin. While the clarified water moves to send
filters for further treatment.

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• Sand Filters (930-Me6a/B/C/D)
The clarified water from Clarifiers flows to four rapid gravity
type sand filters each of which id designed to have to
capacity of 50% of the max design flow rate. The sand
filters perform dual activities i.e. to filter the treated waste
water to Saim Nala canal.
The sand Filter media comprises of a top layer of Anthracite, middle
layer of sand and bottom layer of Graduated support Gravel. These
filters are designed for independent operation so that one filter may
be taken from service for backwash while other three treat the full
plant flow.
Each sand filter has inlet weir (a channel), arranged to prevent the
water falling directly onto media and a wash water weir (collecting
channel) designed to minimize loss of media while optimum removal
of directly wash water. Two back wash pumps are installed in back
wash sump which is used to carry out to wash out the waste solid
collected in filter media and return the filter to clean state so it is
again ready for service. A Sand filter Back Wash Air Blower is
installed to provide air which agitates and loosens the trapped
particles from media when then assists in their removal during
washing process.
Filter backwashing is manually controlled Backwash water is collected
in the washed water sump. The washed water transfer pumps pump
the backwash water from Sump to Equalization tank. The treated
water from sand filter is transferred to treated water sump through
treated water transfer pumps.
iii) Slop oil recovery system:
This system is carried out manually in the field. All the skimmed oil
produced throughout the treatment plant i.e. from process effluent
skimming sump, tank-age effluent skimming sump and API skimmed oil is
transferred to slop oil holding tank.
In this tank, skimmed oil is heat by using heat exchanger No. 1 (930-E6)
to loosen the emulsions and then emulsion breaking polymer is injected in
circulation line while the oil was being re-circulated in its own tank. Oily
Water is sent back to API oil/ water separator for further treatment while
emulsion breaking slop oil is record to emulsion breaking tank (930-TK7).
Same procedure is repeated again to finally remove water from the slop
oil. Heat s provided using heat exchanger No. 2 (930-E7) and injecting
demulsifying chemical. Water recovered from here is again sent o API oil/
Water separator while sending oil to light slop tank (935-TK47) in tank-
age area.

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iv) Spent caustic neutralization system:
It is an important system of ETP that collects the spent caustic solution
from the process units and neutralize it to actual pH before sending it to
WTP for treatment purposes. It is also manually operated. The higher pH
caustic soda is collected through Ground Piping. To neutralize the caustic
soda, it is sent o neutralizing Drum, Caustic soda circulates in the drum
through neutralizing heater and cooled down using neutralizing waste
coolers. As caustic Soda is circulating, sulfuric acid is injected into drums
using sulfuric acid transfer pumps. The neutralized and cooled caustic
soda is again transferred to neutralization tank (930-TK2) in WTP using
pumps for further processing.
v) Closed aromatics waste system:
This system collects the aromatics waste and light hydrocarbons by
closed system to minimize the vapor exposure to the operator. The
aromatics waste transfer to the light slop tank (945-TK47) by the lifting
pumps after cool down by an aromatics cooler
vi) Waste water treatment system (WTP):
This system treats the effluent waste water from the oily water collection
system to meet the stipulated effluent limits for the World Bank Oil
Refinery Effluent Guidelines and sent it to the final lift station sump.
Then, the treated effluent water from WTP is sent to the final lift station
basin to transfer them to Saim Nallah Canal together with the treated
sanitary water from the sanitary waste.
vii) Oily sludge handling system:
This system collects the oily sludge from API separator, DAF units and
various oily sludge from oil slop tank and it is collected in oily sludge
settling Tank (930-v9). Oily sludge from oily sludge settling tank is
transferred to oily sludge Thickener (930-ME11) using oily sludge feed
pumps (930-P55A/B). These pumps are air driven diaphragm types. Oil
sludge Thickener is designed to increase the amount of solids conc. in the
sludge. It is circular designed tank with an inverted conical shaped
bottom and filled with rake. The scraper drive rotates rake making a slow
stirring action and settling the solids to bottom of tank. The clear
supernatural overflows from the top of thickener and Gravitates backs to
API separator. Oily sludge transfer pump the thickened sludge to oily
sludge centrifuge Decanter is pumped to Equalization tank (930-Tk2) by
Transfer pump while it discharges the dried sludge cake directly onto oily
sludge cake conveyor (930-ME85) who transfers the sludge cake to open
container for the removal from site.

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A polymer is also injected into thickened oily sludge before pump it to
centrifuge for dewatering. An in-time mixer is installed after dosing
polymer for adequate mixing of polymer solution.
viii)Bio-sludge handling system:
This system treats the bio sludge produced from the biological treatment
plant processes i.e. Aerobic Basins, Clarifiers and Sanitary waste
Treatment plant and this bio sludge is wasted to Aerobic Digester (930-
Tk60) which helps in complete digestion of sludge and thickness the
solids. Oxygen to activate and accelerate the aerobic digestion of sludge
is supplied through air blowers which maintain DO of mg/L. Bio-sludge
Feed pumps (930-P60A/B) pumps the sludge from Aerobic Digester to
bio-sludge thickener. They are air driven diaphragm type pumps. The bio-
sludge thickener (930-ME60) is designed to increase solid concentration
in sludge before it is fed to bio-sludge Belt Press (930-ME61). The rake
slowly stirs the effluent, settling the solids into the bottom of tank. Clear
supernatural overflows and fed to washed water sump (930-ME30).
Polymer is also injected into the thickened sludge as the sludge is fed to
Belt Press. Bio-sludge Belt Press dewaters the bio-sludge to produce the
dried sludge cake. Sludge cake is discharge to bio-sludge cake conveyor
who discharges it into open container for final disposal. All the filtrate
from Bio sludge Belt Press (930-ME61) is collected in Bio-Sludge Filtrate
Tank (930-TK62) and transferred it to bio-sludge thickener again via belt
process filtrate transfer pump (930-P58).
ix) Sanitary waste treatment plant:
All the sanitary waste from offices, buildings, kitchens, toilets is moved to
sanitary waste treatment system. It basically consists of two rotating
biological contractor units (930-ME70 A/B) who receives and biologically
treat the sanitary waste from refinery area.
All sanitary waste moves over the bar screen to remove debris and large
floating materials. It flows to upwards through parallel plates of Aerobic
Treatment nit. Flow is mixed with oxygen and the unit rotates, equalizing
and homogeneously mixing the oxygen with effluent by providing
attachment of micro-organisms growth on platform creating biomass.
This helps in promoting rapid aerobic reaction. It is then sent to final
settlement tank for settling the solids from the outlet flow. Separated
sludge is transferred to Bio-sludge Digester through air driven diaphragm
sanitary sludge transfer pumps. The sanitary water overflowed is flowed
to hypochlorite contact tank for Disinfection. It contain no of baffles to
give the proper time of contact between disinfect and effluent after final
settling tank. Then disinfection overflows the outlet weir to sanitary
treated Effluent Tank (930-TK73). The transfer pumps pumped the
effluent from tank to either biological aeration basin (930-ME5 A/B). If
the level of BOD is low there or final lift station sump (930-ME7)

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ADDITIONAL ASSIGNMENTS
Assignment No 1:
1. What is the importance of equalization tank in the effluent treatment
plant?
A tank that serves to create a more uniform water body thus eliminating wild
variations in the composition and flows of the incoming water is known as
equalization tank.
The influent to effluent treatment system varies in flow and concentration of
pollutants because the discharges from the manufacturing and utility processes
are not constant. This variation affects the operation of the ETP and could
adversely affect the effluent quality from the plant.
The objective of equalization is to minimize or control fluctuations in wastewater
characteristics in order to provide optimum conditions for subsequent treatment
processes.
There are two common types of flow equalization tank:
• In-line equalization tank
• Side-line equalization tank
•
In-line and side-line equalization tanks are both effective ways to equalize flow
volumes, but in-line equalization is more effective for levelling out the variations
in influent concentration because the entire flow is blended with the entire
contents of the holding tank.
2. Describe aerobic and anaerobic processes in effluent treatment plant?
Aerobic treatment process:
An aerobic treatment unit pre treats wastewater by adding air to break down
organic matter, reduce pathogens, and transform nutrients. Compared to
conventional septic tanks, aerobic treatment unit breaks down organic matter
more efficiently, achieve quicker decomposition of organic solids, and reduce the
concentration of pathogens in the wastewater.
The major advantages of aerobic treatment process is
• Volatile solids reduction meets or exceeds that of anaerobic digestion.
• The stabilized sludge is free of offensive odour and an excellent fertilizer.
• Supernatant BOD concentrations are lower than that of anaerobic
digestion.
• Operation is relatively easy.

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The capital cost and operational cost of aerobic digestion is less compared to
anaerobic digestion. Aerobic digestion process is an important practice of
managing sludge and stabilizing sludge in the treatment of waste water plants.
The micro organisms are fed in to aerobic digesters over the organic compound
to reduce the biochemical oxygen demand of sewage and suspended solids in
the wastewater. The organic compounds are converted to carbon dioxide.
The aerobic treatment helps in easy decomposition of organic matter present in
the sludge that comes out from anaerobic digestion treatment system. The left
out organic compound in aerobic digestion system can be either land filled or
disposed off on agricultural field. In some cases sludge’s from aerobic digestion
are incinerated before disposal on to land fill or onto agricultural land. The
treated sludge can be recycled in to anaerobic digester to convert the organic
compounds into biogas, carbon dioxide and water.
When the sewage sludge is placed in aerobic environment, then the volatile
solids are reduced in no time with the optimal supply of oxygen. This mechanism
is related to microbial protoplasm oxidation where energy helps in balancing the
function of cell. The initial process of aerobic sludge digestion is similar to
endogenous respiration of cellular material. Aerobic digesters are generally used
as adequately mixed reactor. The optimal configuration of aerobic digesters
helps in easy disposal of sludge.
Anaerobic treatment process:
Anaerobic wastewater treatment uses biological agents in an oxygen-free
environment to remove impurities from wastewater. After undergoing such a
treatment, water can be safely released back into the environment. The
biological agents used in the process are microorganisms that consume or break
down biodegradable materials in sludge, or the solid portion of wastewater
following its filtration from polluted water.
Anaerobic wastewater treatment is also known as anaerobic digestion due to
the action of the microorganisms. An excellent way to decrease the amount of
organic matter leftover in things such as sewage and leftover food, anaerobic
digestion is typically a component of any biological wastewater
treatment system.
Usually, the anaerobic process takes place in sealed tanks, located either above
or below the ground. During the initial stages of the sludge breakdown, the
microorganisms, which are mostly bacteria, convert the waste into organic acids,
ammonia, hydrogen and carbon dioxide. In the final stages of anaerobic
wastewater treatment, the remains of the sludge are converted, by a single-
celled microorganism known as a methanogen, into a biogas consisting
of methane and carbon dioxide.

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An additional benefit of anaerobic wastewater treatment is its reduction of
gas emissions. The biogas that results from the anaerobic wastewater
treatment may actually be harnessed and used as an alternative power source
for cooking, lighting, heating and engine fuel. In other words, by capturing and
utilizing the methane and carbon dioxide produced by anaerobic digestion, the
biogas is not released into the atmosphere.
In developing countries, government-funded programs are available to help
power single homes and farms with the biogas produced by on-site anaerobic
digestion. The United Nations also offers funding to anaerobic digestion
programs in the developing world, provided proof of reduced gas emissions is
available.
3. Define and briefly explain the following:
Sludge volume index (SVI):
The sludge volume index (SVI) is the volume in millilitres occupied by 1 g of a
suspension after 30 min settling. SVI typically is used to monitor settling
characteristics of activated sludge and other biological suspensions. Although
SVI is not supported theoretically, experience has shown it to be useful in
routine process control.
Sludge Volume Index (SVI) is a very important indicator that determines your
control or rate of de sludging on how much sludge is to be returned to the
aeration basin and how much to take it out from the system. It actually serves
as a very important empirical measurement that can be used as a guide to
maintain sufficient concentration of activated sludge in the aeration basin
whereby too much or too little can be considered detrimental to the system’s
overall health. As an experienced operator or engineers that operate the
wastewater treatment plant, a tight control must be put in place to adjust the
MLSS value to the desired concentration based on the set limit SVI to be used as
a guide.
Settled sludge volume (mL/L) X 1000
SVI =
Suspended solids (mg/L)
MLSS:
The amount (mg/L) of suspended solids in the mixed liquor of an aeration tank is
mixed liquor suspended solids. Mixed liquor is a mixture of raw or settled
wastewater and activated sludge contained in an aeration basin in the activated
sludge process.
In order to test the mixed liquor suspended solids (MLSS) a well-mixed sample
should be filtered through a weighed standard glass-fibre filter. The residue left

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on the filter is dried to a constant weight at a temperature between 103°C and
105°C. The increase in weight of the filter represents the total suspended solids
of the sample. Large floating particles or submerged agglomerates of no
homogenous materials from the sample may be excluded in the total suspended
solids measurements if it is determined that their inclusion is not representative
of the entire sample
MLVSS:
That portion of Mixed Liquor Suspended Solids (MLSS) that will vaporize when
heated to 600°C (1,112°F). This volatile fraction is mainly organic material and
thus indicates the biomass present in the aeration tank. The material that does
not vaporize in this test, mostly inorganic substances, is said to be fixed.
The biomass solids in a biological waste water reactor are usually indicated as
total suspended solids (TSS) and volatile suspended solids (VSS). The mixture of
solids resulting from combining recycled sludge with influent wastewater in the
bioreactor is termed mixed liquor suspended solids (MLSS) and mixed liquor
volatile suspended solids (MLVSS). The amount (mg/L) of organic or volatile
suspended solids in the mixed liquor of an aeration tank. This volatile portion is
used as a measure or indication of the microorganisms present.
Food to microorganism ratio:
The metabolism of the organic matter results in an increased mass of
microorganisms in wastewater treatment systems. To maintain a proper balance
between the influent sewage (food) and the mass of organisms produced, it
becomes necessary to waste the excess microorganisms so formed during
wastewater aerobic treatment. This food-to-microorganisms (f/m) ratio also
termed, as sludge-loading ratio is an important feature of the aeration tank,
which is needed in the operation of activated sludge process.
It is necessary that proper f/m ratio is maintained in the aeration tank in order to
have an optimum operation by the activated sludge bacteria. When the f/m ratio
is high, microorganisms are in log growth phase, which is characterized by
excess food and maximum rate of metabolism. As a result, wastewater aerobic
treatment microorganisms remain in a dispersed state and neither settles out of
solution by gravity in the settling tank, nor can be separated easily from the
effluent to be returned to the aeration tank.
However, at low f/m ratio, the metabolic activity is in endogenous phase where
the rate of metabolism by wastewater microorganism is low. The large mass of
waste microorganisms present then competes for the relatively smaller amount
of food available in the influent, and under aerobic conditions rapidly flocculates
to settle out of solution by gravity. As such, BOD removal efficiency is quite high
in the endogenous phase.

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BOD at 5 days:
Biochemical oxygen demand or B.O.D. is a chemical procedure for determining
the amount of dissolved oxygen needed by aerobic biological organisms in a
body of water to break down organic material present in a given water sample at
certain temperature over a specific time period. It is not a precise quantitative
test, although it is widely used as an indication of the organic quality of water. It
is most commonly expressed in milligrams of oxygen consumed per liter of
sample during 5 days of incubation at 20 °C and is often used as a robust
surrogate of the degree of organic pollution of water.
Legend has it that the 5-day BOD (Biological Oxygen Demand) test was
developed in England. Sewage was dumped in a river and it took five days for it
to reach the ocean, hence the five-day incubation requirement in the BOD
method.
BOD at 7 days:
BOD is a measure of the content of biologically degradable substances in
sewage. The substances are broken down by microorganisms in the presence of
(and with the consumption of) oxygen. Oxygen demand is measured in terms of
the oxygen consumed by microorganisms over a period of 5 days (BOD5) or
seven days (BOD7).
Biochemical oxygen demand (BOD) is a parameter in the assessment of the
purity of water. BOD is the quantity of oxygen (dissolved in water) which is
consumed in the biological breakdown of the organic substances in a water
sample. Biochemical oxygen demand is indicated in milligrams of oxygen per litre
and represents an approximate measure of the presence of organic pollutants
and bacteria.
Pure water has a BOD of 0, while wastewater may have values of several
hundred milligrams per litre. BOD7 indicates the quantity of oxygen consumed
over 7 days.
COD:
The chemical oxygen demand (COD) test is commonly used to indirectly
measure the amount of organic compounds in water. Most applications of
COD determine the amount of organic pollutants found in surface water
(e.g. lakes and rivers), making COD a useful measure of water quality. It is
expressed in milligrams per liter (mg/L), which indicates the mass of oxygen
consumed per liter of solution.
The chemical oxygen demand test procedure is based on the chemical
decomposition of organic and inorganic contaminants, dissolved or suspended in
water. The result of a chemical oxygen demand test indicates the amount of

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water-dissolved oxygen consumed by the contaminants, during two hours of
decomposition from a solution of boiling potassium dichromate. The higher the
chemical oxygen demand, the higher the amount of pollution in the test sample.
For the contaminants that can be oxidized biologically, the biological oxygen
demand (BOD) method is used.
4. Describe effect of BOD, COD and sludge volume index on treatment
process?
Effect of BOD on water quality:
Biological Oxygen Demand (BOD) is one of the most common measures of
pollutant organic material in water. BOD indicates the amount of organic matter
present in water. Therefore, a low BOD is an indicator of good quality water,
while a high BOD indicates polluted water. Dissolved oxygen (DO) is consumed
by bacteria when large amounts of organic matter from sewage or other
discharges are present in the water. DO is the actual amount of oxygen available
in dissolved form in the water. When the DO drops below a certain level, the life
forms in that water are unable to continue at a normal rate. The decrease in the
oxygen supply in the water has a negative effect on the water quality. Growth of
certain types of weeds can cause dramatic changes in water body. Energy is
derived from the oxidation process. BOD specifies the strength of sewage.
The BOD test serves an important function in stream pollution-control activities.
It is a bioassay procedure that measures the amount of oxygen consumed by
living organisms while they are utilizing the organic matter present in waste,
under conditions similar in nature.
Effect of COD on water quality:
The chemical oxygen demand (COD) is a measure of water and wastewater
quality. The COD test is often used to monitor water treatment plant efficiency.
This test is based on the fact that a strong oxidizing agent, under acidic
conditions, can fully oxidize almost any organic compound to carbon dioxide. The
COD is the amount of oxygen consumed to chemically oxidize organic water
contaminants to inorganic end products.
The COD is often measured using a strong oxidant (e.g. potassium dichromate,
potassium iodide, potassium permanganate) under acidic conditions. A known
excess amount of the oxidant is added to the sample. Once oxidation is
complete, the concentration of organics in the sample is calculated by measuring
the amount of oxidant remaining in the solution.
The COD test only requires 2-3 hours, while the Biochemical (or Biological)
Oxygen Demand (BOD) test requires 5 days. It measures all organic
contaminants, including those that are not biodegradable. There is a relationship
between BOD and COD for each specific sample, but it must be established
empirically. COD test results can then be used to estimate the BOD of a given

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sample. Unlike for the BOD test, toxic compounds (such as heavy metals and
cyanides) in the samples to be analyzed do not have an effect on the oxidants
used in the COD test. Therefore, the COD test can be used to measure the
strength of wastes that are too toxic for the BOD test. Some organic molecules
(e.g., benzene, pyridine) are relatively resistant to dichromate oxidation and may
give a falsely low COD.
Effect of SVI on water quality:
The Sludge Volume Index (SVI) represents the volume occupied by the
concentrated sludge that is obtained after the sludge is allowed to settle for a
period of half an hour. Only the volume occupied by 1gm of the sludge is
considered when calculating the index. This index is also used primarily to asses
the settling ability of the particles in the activated sludge, as well as the settling
capacity of other types of suspensions in wastewater.
A calculation that indicates the tendency of activated sludge solids (aerated
solids) to thicken or to become concentrated during the
sedimentation/thickening process.
Sludge Volume Index (SVI) is a very important indicator that determines your
control or rate of de sludging on how much sludge is to be returned to the
aeration basin and how much to take it out from the system. It actually serves
as a very important empirical measurement that can be used as a guide to
maintain sufficient concentration of activated sludge in the aeration basin
whereby too much or too little can be considered detrimental to the system’s
overall health. To put it in a lay man’s term, de sludging or sometimes referred
to as recycling sludge process, actually plays a very important role because the
whole operation is needed to somehow strike a balance between removing dead
or aged bacteria out of the systems or to determine how much goes back to the
aeration pond.
Activated sludge pond is designed to allow adjustments on the amount of
sludge return and also the take off rate. Regular de sludging must be carried out
to remove the aged sludge so that the new bacteria can regenerate and allowed
to grow. As an experienced operator or engineers that operate the wastewater
treatment plant, a tight control must be put in place to adjust the MLSS value to
the desired concentration based on the set limit SVI to be used as a guide.
5. National Environmental Quality Standards (NEQs):
Parameters Current standards
pH 6 -10
Oil and grease (ppm) 10
Suspended solids (ppm) 30
Sulphates (ppm) 600
COD (ppm) 150
BOD (ppm) 80

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Assignment No 2:
1. Describe belt press?
Belt-press Device:
A Belt Filter Press is a Bio solids/sludge dewatering device that applies
mechanical pressure to chemically conditioned slurry, which is sandwiched
between two tensioned belts, by passing those belts through a serpentine of
decreasing diameter rolls. The machine can actually be divided into three zones:
• Gravity zone, where free draining water is drained by gravity through a
porous belt
• Wedge zone, where the solids are prepared for pressure application
• Pressure zone, where medium, then high pressure is applied to the
conditioned solids.
Typically, a belt filter press receives a slurry ranging from 1-4% feed solids and
produces a final product of 12-35% cake solids. Performance depends on the
nature of the solids being processed.
2. Describe Centrifuge Unit?
Centrifuge equipment:
One of the most common pieces of equipment used to separate materials into
sub fractions in a biochemistry lab is the centrifuge. A centrifuge is a device that
spins liquid samples at high speeds and thus creates a strong centripetal force
causing the denser materials to travel towards the bottom of the centrifuge tube
more rapidly than they would under the force of normal gravity.
Centrifugation is one of the most important and widely applied research
techniques in biochemistry, cellular and molecular biology, and in medicine.
Current research and clinical applications rely on isolation of cells, sub cellular
organelles, and macromolecules, often in high yields. A centrifuge uses
centrifugal force (g-force) to isolate suspended particles from their surrounding
medium on either a batch or a continuous-flow basis. Applications for
centrifugation are many and may include sedimentation of cells and viruses,
separation of sub cellular organelles, and isolation of macromolecules such as
DNA, RNA, proteins, or lipids.
3. Explain rotating biological contractors?
Rotating biological contractors:
A rotating biological contactor or RBC is a biological treatment process used in
the treatment of wastewater following primary treatment. The primary

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treatment process removes the grit and other solids through a screening
process followed by a period of settlement. The RBC process involves allowing
the wastewater to come in contact with a biological medium in order to
remove pollutants in the wastewater before discharge of the treated
wastewater to the environment, usually a body of water (river, lake or ocean).
A rotating biological contactor is a type of secondary treatment process. It
consists of a series of closely spaced, parallel discs mounted on a rotating shaft
which is supported just above the surface of the waste water. Microorganisms
grow on the surface of the discs where biological degradation of the
wastewater pollutants takes place.
P&ID’s
Please see attachments on Page No. 36.

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ENVIRONMENTAL ASSESSMENT REPORT ON DHDS INSTALLATION
Overview:
It was an immense understanding for me as an internee at PARCO under the
supervision of my reference engr. Syed Mehmood Mehdi to visit the diesel hydro
desulphurization unit to have a convenient exposure while analyzing its EIA report
available in the library. My Environmental Assessment Report is produced with the
help of my reference engr. of TSD department and the useful reading and consulting
material available in the library of the main office of PARCO.
The nucleus purpose of visiting the diesel hydrodesulphurization unit was to
recognize environmental impacts allied with construction, operation of installation at
PARCO considering the requirements of the Pakistan Environmental Protection Act
1997 and Pakistan Environmental Assessment Procedures.
Objective of Study:
The overall objective of this report is providing me with the understanding of impact
assessment of adverse environmental impacts of DHDS installed unit. Learning to
minimize the impacts through early recognition and avoiding the impacts on
susceptible areas with the effort to learn the development of appropriate
improvement measures for inescapable impacts was the intention of all investigation,
consideration and trip to the DHDS unit location.
The study of EIA report of DHDS also enabled me to understand the route and the
fundamentals of execution of the study of environmental impact assessment of any
plant or unit under inspection
DHDS Project Installed Overview:
Diesel produced by domestic refineries contains about 0.8 to 1 wt% sulfur. The
Government of Pakistan advised all refineries including PARCO to reduce sulfur
content diesel to meet Euro-2 standards. PARCO installed a new state of art Diesel
Hydrodesulphurization Unit (DHDS), licensed by UOP, having a design capacity of
26,000 BPSD. The proposed project produces the high quality diesel having the low
sulfur contents with max sulfur content of 250 wppm under first phase and 10 wppm
in second phase, in order to meet the low sulfur diesel Euro-2 specification (500
ppm). The project is under operation for one year and it created positive
environmental impacts at the production site as well as at consumer level. The
combustion of low sulfur diesel reduced the sulfur level in air both at local and
regional level. Overall this installation significantly contributed to environmental
quality and safety to human health all over Pakistan.
Environment Impact Assessment Report Analysis On DHDS:
The EIA report was planned aiming to contribute in the development and function of
unit minimizing the potential negative impacts and maximizing benefits during

of 35
construction and operation. Here, EIA formed an integral part of project design
process.
The EIA report was gathered by identifying the issues and impacts, establishing an
environmentally sound preferred option for achieving all the objectives, identifying
and predicting the environmental effects of the proposed project while determining
its relative importance and then clearly document all the impacts of the proposal.
Environmental impact assessment is essential as it gives complete understanding of
nature of existing environment, prior to its interaction with the proposed activity. This
can be achieved through the detailed review of all project specified monitoring
studies to collect the data in the following area i.e.
• Terrestrial ecology
• Water quality characteristics
• Archaeology
• Flora and fauna
• Traffic
• Ambient air and noise conditions
• Local socio-economic conditions
The approach adopted in the EIA study of DHDS unit is to assess the impact of
proposed project of existing environment and define the potential impacts avoided
through the careful choice of location, technology and materials.
Role of Policy and Legal Administration In The EIA Of DHDS Unit:
Two organizations, the Pakistan Environmental Protection Council (PEPC) and the
Pakistan Environmental Protection Agency (Pak-EPA) are responsible for
administering the provision of the Pakistan Environmental Protection Act, 1997. The
Pak-EPA ensures compliance with NEQS and establishes monitoring and evaluation
system and is responsible for identifying the need of legislation where ever
necessary. Its function is to review and approve the EIA reports of projects
undertaken in their respective jurisdictions.
EIA report analysis gave a thorough overview of client responsibilities and its
interaction with the other agencies. The client is responsible for the provision of
complete documents required by Pak-EPA; provide logistic support and meeting
Punjab Government criteria.
Environmental and Social Study:
It is highly important to describe the prevailing environmental and social conditions
present within the proposed project area and details the importance of these
resources in terms of local, national and international context which can be derived
by combination of desk study and field survey.

of 35
Project site was located in Mehmood Kot, Muzaffarghar District lies between Chenab
and Indus river. It is the inner most zone of Thal desert where water can be brought
to land by means of inundation canals. Area is flat and soil studies indicate that the
sediment consist of fine to medium grained sand, silt, clay. The site is protected
against flooding by the river Indus. Topography of area is flat with no as such
noticeable variation in the elevation. Area is not thickly populated and surrounded by
agricultural lands having extreme hot, arid climate.
The rainfall data of the project area, temperature, humidity and wind direction are
also calculated. The ambient air quality is monitored for priority pollutants including
carbon dioxide, sulfur dioxide, nitrogen dioxide and particulate matter by using
portable automatic analyzer. There are also significant numbers of water resources
existing in and outside the PARCO industry in the form of groundwater and surface
streams whose characteristics determining parameters should be well within the limits
set by WHO drinking water criteria and NEQS quality standards. Noise measurements
are also made at a height of 1.5m above the ground level and LAeq is monitored for
24 hour at individual location which should be within acceptable NEQS standards. A
socio-economic survey should be carried out near project area with the help of semi-
structured open-ended questionnaires to identify the various stakeholders and their
opinion regarding the proposed project to find out their social, economical and health
profile. In this way, one can have the easy access to the problems faced by
employees regarding health care facilities, drinking water, availability of Sui gas,
provision of sewage system and recreational facilities etc.
Impact Prediction and Evaluation:
The analysis of environmental releases during construction and operation is also
necessary section of EIA report. The project interaction with environmental is
primarily by way of release of emissions, generation of waste materials, consumption
of resources and accidental releases and spills etc. it is important to qualify the
emissions regarding air, liquid effluents, solid waste, hazardous wastes, noise and
accidental releases.
The major pollutants in air include TSP, NOx, SOx, CO, un-burnt hydrocarbons and
VOC. Liquid effluents contain BOD, COD, and TSS from the machinery washings,
mobile equipment washing, vehicle washing and sewage from site offices and
construction camps. This effluent is sent to treatment plant at site and is discharged
after necessary treatment. Solid waste from construction debris, excavated soil, scrap
metal from construction and equipment fabrication is land filled onsite or recycled to
the extent possible. Solid and liquid wastes from spills/leaks and empty containers of
paints/solvents etc are safely handled and stored by ensuring proper practices.
There are also major releases during operational phase. The exhaust samples of
transport, standby generators, vehicles, valves and storage areas are monitored by
the C.E. Lab of PARCO, showing the concentration of these gases well under the
NEQS limits. Liquid effluent contains liquid effluent from various process units,
sanitary water and vessel/floor cleaning from utility areas. They are treated in

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effluent treatment plant. The solid waste during operation is stored at designated
waste storage area at the facility and finally disposes off through an approved
contractor or sold to potential buyers for recycling.
The assessment of potential impacts during construction and operation is carried out
utilizing both qualitative and quantitative assessment techniques and the impacts are
rated on the basis of severity and likelihood of impact.
There are certain beneficial impacts from the project in terms of generation of
employment opportunities, development of the project are and the nearby
communities. The objective of impact assessment is to assess the adverse impacts
and rate them to identify appropriate improvement measures.
Improvement Measures:
EIA analysis also presents the improvement or alleviation measures the project
should adopt to ensure the practical. Cost-effective and sufficient approach to the
environment it is deigned to ensure that the residual adverse impacts resulting from
work are reduced to an acceptable level, whilst maximizing the benefits of the
project. The operations equivalent procedures for local procurement, waste
management, spill prevention and noise lessening will be maintained. It includes fire
and safety management and wastewater management.
The following are the impacts of DHDS unit installed under study where measures
can be taken
• Dust formation : use of water sprinkles, safe driving speed, controlled heavy
earth moving equipments, wetted stockpiles of fine material, dust masks and
safety goggles and good housekeeping
• Exhaust emissions: use of new diesel generators, less probability of human
intervention, devices properly tuned, serviced and monitored, vent of exhaust at
specified height and use of low emission content fuel.
• Noise: generators installed at isolated place, regularly noise monitoring,
minimization of night time work activities, insulation, use earplugs and personal
protection equipment
• Natural sources: no expected damage to ecology and resulting impacts are
insignificant
• Ambient air quality: fixed roof on intermediate diesel tank for DHDS unit, double
sealing, low NOx burners, personal protection equipment, VOC emission control
and properly serviced and monitored vehicles and devices.
• Soil conditions: storage and process units marked, drain of oil spills should not
contact with rainwater runoff, emergency response plans, cathodes protection and
incineration.
• Ground water: effluent treatment plant, provision of dykes, avoiding the
infiltration of oil into groundwater, monitoring of ground water, incineration of oily
sludge, proper drainage and good housekeeping.
• Solid waste: proper land filling, regulatory collection of municipal waste,
collection of hazardous waste in proper drums, indication of the type of waste,

of 35
proper storage and recycle of waste, use of bio sludge as fertilizers, adequate
disposal techniques and staff training regarding sludge collection, handling and
storage.
• Safety and occupational health: regularly inspection, emergency response
plans and protective personal equipments
Environment Management Plan (EMO):
The EIA report has identified several environmental impacts which can be managed
by EMP and monitoring plan which serves to mange environmental impacts and
focuses on implementation of improvement measures in its true sense against likely
environmental impacts.
Conclusion:
The comprehensive study of environmental impact assessment report of DHDS unit
installed enabled me to understand the fundamental need of this study and gave me
a keen insight to its practical approach that facilitated me to understand the
theoretical course I took in the university. The detailed EIA report considered all the
minor details and particulars the environment could face during its construction, its
improvement measures and implementation vision and the regulatory monitoring of
emissions, effluent and wastes generated during its operation. The surrounding
environment and community health and safety were considered. Tabulated
information and third party monitoring reports were given for the complete
understanding of the reader.

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