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Oil & Gas industry Waste Management

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A major challenge throughout the O&G sector is that many waste streams can become contaminated by oily or hazardous fluids, and radioactivity requiring careful handling, treatment and disposal. Generated wastes at terminals may include tank bottom sludge; this must be periodically removed to maintain product quality or tank storage capacity; as well as spill cleanup materials and soils contaminated with oil. Typically, sludge is composed of water, residual product, and various solids including sand, scale, and rust. Tank sludge and spill cleanup materials should be dealt via re-processing for product recovery or as a waste at a licensed facility handling this kind of material in an environmentally sound manner. The aims of this review are: To identify the challenges facing the oil industry in achieving sustainable management of all wastes from inshore /offshore production facilities, and To compare and contrast the most important factors that affects waste management in developed oil areas with those in less developed, emerging oil
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Oil & Gas industry Waste
Management
Prof. Dr. Mamdouh F. Abdel-Sabour
Environmental Consultant
International Innovative Environmental Solution Center (IIESC)
Introduction
A major challenge throughout the O&G
sector is that many waste streams can
become contaminated by oily or hazardous
fluids, and radioactivity requiring careful
handling, treatment and disposal.
Generated wastes at terminals may include
tank bottom sludge; this must be periodically
removed to maintain product quality or tank
storage capacity; as well as spill cleanup
materials and soils contaminated with oil.
Typically, sludge is composed of water,
residual product, and various solids including
sand, scale, and rust. Tank sludge and spill
cleanup materials should be dealt via re-
processing for product recovery or as a
waste at a licensed facility handling this kind
of material in an environmentally sound
manner.
Dealing with municipal solid-like waste,
and commercial and industrial waste in a
sustainable way presents significant
difficulties especially in the confined
working environments offshore.
To identify the challenges facing
the oil industry in achieving
sustainable management of all
wastes from inshore /offshore
production facilities, and
To compare and contrast the
most important factors that
affects waste management in
developed oil areas with those in
less developed, emerging oil
areas.
objectives
Waste Management
1 Reduction: important in
manufacturing. Purchasing
products that includes these
features supports source
reduction. When a method is
chosen to reduce waste, pilot
testing may be suitable for initial
evaluation. Source reduction can:
Save natural resources;
Reduce pollution;
Conserve energy;
Reduce the toxicity of the
waste; and
Save money for consumers
and businesses alike.
2- Reuse: Use materials or
products that are reusable, such
as chemical containers, waste oil
for road building, burning waste
oil, and energy recovery.
Waste Management
3- Recycling/ Recovery: Waste
into usable/ or energy derived
from waste material, such as
scrap metal recycling, recycling
drilling mud used in the drilling
debris, oil recovery and reservoir
sedimentation water exploration
and production manufacturing
processes.
4 - Treatment: Detoxification
degradation, detoxification and/
or neutralization of the
remaining processes including
biological methods, incineration,
thermal analysis, neutralization,
chemical methods, stabilization
methods, and physical filtration
using centrifugal force.
Energy recovery
Waste-to-energy which is a proven technology used globally
to generate clean, renewable energy from the sustainable
management of municipal solid waste
Multiple feedstock capability: Capable of receiving,
handling, processing and disposing, different types of wastes
(e.g., MSW, IHW) concurrently.
Complete destruction of wastes: Plasma gasification
process is a NO BURN process hence, it does produce
residuals, i.e., fly & bottom ashes as typically found with
incinerators. Fly & bottom ashes are harmful, may contain
heavy metals and require secure landfilling. Since plasma
gasification does not produced ash, landfilling will no longer
be a requirement.
Maximum energy recovery from wastes: Plasma
gasification process is designed and engineered to ensure
efficient energy recovery from wastes.
Environmentally friendly: Operating at temperature range
of about 3,000oC in the Gasification Zone in an oxygen
starved environment, are realised in the plasma reactor
therefore, plasma gasification process presents no
opportunity for formation of hazardous flue gases, e.g.,
dioxin & furans, SOx and Nox.
Type of generated wastewater
Storm and Process Wastewater Treatment
1)Storm-water
Contaminated storm water quality and volumes may depend on site-specific considerations
including overall housekeeping and spill prevention practices, rainfall, and total runoff area.
Natural gas processing facilities should provide secondary containment where liquids are
handled, segregate contaminated and non-contaminated storm water, implement spill control
plans, and route storm water from process areas into the wastewater treatment unit.
2)Tank Bottom Water
Water that separates and settles to the tank bottom should be periodically drained from the
bottom of the tank, resulting in a liquid effluent of oily water. Rainwater infiltration,
condensation of moisture from tank vapor space, and water present in the product itself
prior to delivery may all contribute to the presence of water inside product storage tanks.
3)Industrial Process Wastewater
Process wastewater may contain dissolved hydrocarbons, oxygenated compounds, and
other contaminants which should be treated onsite wastewater treatment unit
wastewater
4)Process wastewaters include:
Chemical Wastewater
Chemical drain system collects wastewaters that require neutralization before discharge
via return header of seawater cooling. The pH of the effluent must be adjusted between
6 - 9 in the neutralization sump by batch addition of 30 % HCl or 50 % NaOH.
Oily Wastewater
Oily wastewater must be directed to a retention pond and air floatation package which is
used to reduce oil content below 15 mg/l. Sludge from these treatment units shall be
directed to and treated in the wastewater treatment facilities.
Sour Wastewater:
Sour water from the AGR unit periodically requires disposal with small quantities of sour
condensate from LP sour gas flare drum. These wastewaters are treated by stripping off
gas from the nitrogen rejection unit before discharge to the oil contaminated drain.
For every tonne of hydrocarbon produced in 2010 (including oil, condensates and
gas) 0.6 tonne of produced water were discharged to the marine environment and
1.0 tonne of produced water was re-injected into the ground (OGP, 2011).
Type of generated waste
4) Cooling water
Cooling water may require high rates of
water consumption, as well as the potential
release of high temperature water, residues
of biocides and other cooling system anti-
fouling agents.
5) Hydrostatic testing water
Hydrostatic testing of equipment and
pipelines involves pressure testing with
generally filtered raw water to verify their
integrity and possible leaks detection.
Chemical additives may be added. A hydro-
test water disposal plan should be prepared
considering location and rate of discharge,
chemical use, dispersion, environmental risk,
and required monitoring if the only feasible
alternative for disposal of hydro-test waters
into the sea or to surface water. Hydro-test
water disposal into shallow coastal waters
should be avoided.
7) Ballast water
Gas processing that has a port/terminal shall ensure that
ships with segregated ballasts are used for all products
transport. Facilities that will carry out the ballast water
sampling and analysis should coordinate with Port
Authorities. Ballast water shall be tested to the following
standards prior to discharge.
Parameter
Units
Limit
pH
-
6-9
Biochemical Oxygen Demand (BOD)
mg/l
50
Chemical Oxygen Demand (COD)
mg/l
250
Total suspended solids
mg/l
35
Oil & grease
mg/l
15
Visible oil & grease
-
None
Total Organic Carbon
mg/l
100
Ammonia, as N
mg/l
3
6) Sanitary wastewater
The sanitary drain system receives wastewater from all
process, utility, offsite, and off plot areas including services
expansion facilities. The wastewater should undergo
biological treatment units based on extended aeration and
activated sludge and should be channeled to MBR tertiary
treatment package for further polishing. The use of
detergents, surfactants, and dispersants shall be minimized
except as necessary to maintain a safe workplace.
Hazardous &Non-hazardous Waste
1.Non-hazardous Waste
Non-hazardous industrial
wastes consist mainly of
exhausted molecular sieves
from the air separation unit as
well as domestic wastes. Other
non-hazardous wastes may
include office and packaging
wastes, construction rubble,
and scrap metal.
2.Hazardous Waste
In GTL facilities, hazardous
wastes may include bio-sludge;
used containers and oily rags;
spent catalysts; spent oil,
solvents, and filters (e.g.,
activated carbon filters and
oily sludge from oil water
separators); mineral spirits;
used sweetening; spent amines
for CO2 removal; and
laboratory wastes.
Hazardous waste
Spent catalysts
Spent catalysts from GTL
production are generated
from scheduled
replacements in natural gas
desulphurization reactors,
reforming reactors and
furnaces, reactors for mild
hydro-cracking, and Fischer-
Tropsch synthesis reactors.
Spent catalysts may contain
iron, zinc, nickel, platinum,
palladium, cobalt, and
copper; depending on the
particular process.
Heavy Ends
Heavy ends or distillation residues
from the production of carbon
tetrachloride
Heavy ends from the purification
column in the production of epi-
chlorohydrin
Heavy ends from the fractionation
column in ethyl chloride
production
Heavy ends from the distillation of
ethylene dichloride in ethylene
dichloride production
Heavy ends from the distillation of
vinyl chloride in vinyl chloride
monomer
12
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طفن
NORM wastes generated from oil
and gas production. In gas processing
activities, NORM generally occurs as
radon gas in the natural gas stream.
Radon decays to Lead-210, then to
Bismuth-210, Polonium-210, and
finally to stable Lead-206. Radon
decay elements occur as a film on
the inner surface of inlet lines,
pumps, treating units, and valves
principally associated with ethane,
propylene, and propane processing
streams.
6.1 Management of Basic Waste Types
According to OSHA the
average radium concentration
in scale has been estimated to
be 17.76 Bq/g (EPA, 2011). It
can be much higher (as high as
14,800 Bq/g) or lower
depending on regional geology.
The average concentration of
radium in sludge is estimated
to be 2.775 Bq/g. This may vary
considerably from site to site.
Although the concentration of
radiation is lower in sludge
than in scales, sludge is more
soluble and therefore more
readily released to the
environment. This result poses
a higher risk of exposure.
Scales in pipes and vessels are the most common
NORMs in the petroleum industry. Scales on
equipment are low in volume. Scales are solid
minerals that precipitate from produced water
which has high salinity and contains sulfates
and/or carbonates plus calcium, barium and
strontium. Scale-forming material may also
precipitate on sand and sludge particles and debris
of scale may be mixed with sludge and sand inside
vessels. The most common scales consist of
barium sulfate (BaSO4), strontium sulfate (SrSO4)
or calcium carbonate (CaCO3). The relative
amounts of solid waste vary with the production
area due to the different geological characteristics
of the oil/gas reservoirs.
Management of Basic Waste Types
The most important scale formation
processes are mixing of incompatible
waters and temperature changes. When
scale precipitates from a large volume of
formation/produced water, radium is
concentrated within a small amount of
solid scale such that the radium
concentration in scale exceeds the
radium concentration in the
formation/produced water by several
orders of magnitude.
Approximately 100 tons of scales
per oil well are generated annually
in the United States.
Sludge is composed of dissolved solids
which precipitate from produced
water as its temperature and pressure
change.
Dried sludge, with low oil content,
looks and feels similar to soil. Like
contaminated scale, sludge contains
more Ra-226 than Ra-228.
Disposal petroleum pipes containing
sludge and scale as a technically
enhanced natural occurring radioactive
material (TENORM) leads to internal
and external radiation hazards and
then a significant radiation dose to the
workers.
Sustainable Waste Management Plan
Management plan must consider life
cycle sustainability.
Responsible persons, needed
resources and planned objectives shall
be set in such a way that the variety of
programs and facilities management
system is available.
Waste classification on physical,
chemical and its toxicity must be
identified.
Technical criteria and guidance
documents on oil and gas waste
management have been issued by API
and the Interstate Oil and Gas
Compact Commission (IOGCC)
(Green, 2008) to supplement efforts
to improve such management.
API and OGP provide the starting
point for any company that evaluates
its waste management plan, or
assessing environmental performance
of treatment facilities, both in
developed and less developed
countries (OGP, 2011, API, 2009, OGP,
2008,.
A classification system for waste
streams may be formed in accordance
with the health and environmental
hazards.
Waste Management may consider
practical measures, i.e., reduction of
source, recycle and reuse, recovery,
and final disposal of remaining waste.
These measures are as follows:
Loading / unloading activities should be conducted by properly trained personnel
according to pre-established formal procedures to prevent accidental releases and fire
/explosion hazards. Procedures should include all aspects of operation from arrival to
departure, including wheel blocking to avoid vehicle movement, verification of proper
hose connection and disconnection, connection of grounding systems, adherence to
no-smoking and no-naked light policies for visiting drivers;
For unloading / loading activities involving marine vessels and terminals, preparation
and implementation of spill prevention procedures for tanker loading and off-loading
according to applicable international standards and guidelines which specifically
address advance communications and planning with the receiving terminal;
Facilities should develop a spill prevention and control plan that addresses significant
scenarios and magnitudes of releases. The plan should be supported by the necessary
training and resources. Adequate spill response equipment should be conveniently
available to address the most likely types of spills. Spill cleanup materials should be
managed as discussed below;
Where appropriate, spill control and response plans should be developed in
coordination with the relevant local regulatory agencies;
Above Ground Storage Tanks (ASTs) should be protected from potential collisions by
vehicles, vandalism, located in a secure area, and other hazards. Additional guidance on
ASTs is presented in the General EHS Guidelines.
5. Pollution Prevention
Pollution prevention, including the removal, modification or reduction
operational measures that lead to pollution of land, air or water, such as; waste
prevention, handling, and treatment methods.
API (2001) estimated that in 1985 about 92 % of oil and gas wastes was injected
underground, 4% was discharged into waterways, and 2 % was managed in surface
impoundments.
These methods include:
1) Re-injection,
2) Incineration,
3) Down-hole
4) Oil-Water Separation Technology,
5) Compaction/ Shredding,
6) Waste to Energy,
7) Landfill,
8) Advanced Thermal Treatments (e.g. gasification, pyrolysis),
9) disposal in Salt Caverns,
10) Bio-remediation, and Evaporation pits.
6. CURRENT MANAGEMENT PRACTICES
The major method for waste
management in oil& gas sector
include:
surface impoundment;
land application and
landfilling;
waters source reduction and
recycling;
underground injection; and
discharge to surface.
5. Pollution Prevention
All non-hazardous solid waste from construction or operational
activities shall be managed at the industrial waste facility, once
this becomes operational and is within the terms of User
Agreement.
All offsite waste shipments shall utilize a manifest system for
tracking. Report the summary of all offsite waste shipments to
the environmental Authority each quarter.
All hazardous solid waste shall be safely stored in a contained
facility until such wastes can be treated to a non-hazardous state
or exported to an approved treatment facility as per Basel
Convention.
An inventory of all stored hazardous wastes shall be reported
to the Environment authority each quarter.
5. Pollution Prevention
Any waste material stored on site shall be done at an approved
hazardous Waste storage facility. The storage facility shall not
hold more than 3 months of inventory at any point of time. All
Hazardous waste shall be disposed-off locally or internationally
within 90 days.
Waste Lube oil shall be disposed-off at a facility approved by
environmental authority and reported on the quarterly EMP
report.
Total quantity of solid waste generated on a yearly basis (in
tonnes) shall be forwarded to the environmental authority with
the 4th quarter EMP report. This report shall have a breakdown
of solid waste by three major categories viz., Hazardous, Non-
Hazardous and Inert.
Surface Impoundments
According to EPA (1984), more than 125,000 oil and gas surface
impoundments existed in 1984. Based on EPA data from 1980s (GWA, 2005),
only 2.4 % of the surface impoundments used for oil and gas wastes had
synthetic liners, whereas another 27 % had a natural liner of unknown
composition quality.
Reserve pits are used to temporarily store drilling fluids for use in drilling
operations or waste disposal. Of all materials discharged to reserve pits, an
estimated 90 % are drilling fluids (mostly in the form of drilling muds and
completion fluids) and cuttings.
Adding solidifiers for solidification of pit contents is one potential alternative
(e.g., commercial cement, fly ash, or lime kiln dust) to help immobilize
pollutants and minimize leaching of toxic constituents. One problem in
solidification is after removal of the free liquid fraction of pit wastes, the
remaining pit contents still contains about 30 percent water. In addition, the
use of cement kiln dust, and possibly other solidifiers, increases the volume of
solid waste to be managed (Karami et. al., 2013).
Landfilling and Land Application
The petroleum products from the soil during land farming are largely removed
through biodegradation, volatilization and adsorption (Hejazi et al. 2003). Lighter
petroleum products like gasoline may be removed by volatilization during land farm
aeration process and to a lesser extent, degraded by microbial respiration (EPA,
1994). The mid-range petroleum products like diesel fuel and kerosene contain lower
percentage of lighter constituents than does gasoline. Bio-degradation is more
significant than volatilization for these petroleum products. The dominant
mechanisms that break down heavier or non-volatile petroleum products like heating
oil and lubricating oils are biodegradation. Adsorption also plays an important role in
the dissipation of petroleum products from the soil.
The efficiency of removing petroleum compounds from the soil can be impacted by
the soil moisture. The moisture level in most land farms is kept between 30 and 80%
field capacity (Pope & Mathews 1993; Malina et al. 2002).
Adsorbents like clay and organic matter, which are site-specific can decrease the
bioavailability of toxic compounds and therefore result in a lower risk for higher
organisms (reduction in toxicity) and lower biodegradation efficiency as
contaminants are tightly bound to the soil matrix (Guerin & Boyd 1992). It was
reported that during the last two decades, (Verstraete & Top 1999; Holden & Firestone
1997), that it is possible for the land-farm can treat petroleum products in an
environmentally safe manner.
Deep-Well injection
Injection wells used for disposal are often older wells that
require more maintenance (EPA regulations require
periodic testing of the mechanical integrity of the injection
wells).
For final disposal purposes, about 90 % of produced waters
from onshore oil and gas operations are disposed of in
more than 166,000 underground injection wells (Karami et.
al., 2013).
Produced waters are injected (via gravity flow or pumps)
into saltwater formations, the original formation, or older
(depleted) formations when used for disposal.
5. Pollution Prevention
Class II injection well is equipped with constant
pressure monitoring, corrosion inhibitors, leak
detection, and automatic shutoff.
Many US-States restrict the types of wastes that
can be stored in pits at Class II well sites, and
require lining of these facilities (with either
synthetic or clay liners, depending on site-specific
conditions) and, where groundwater is present,
groundwater monitoring systems is required
(Voutchkov,2011).
In addition, pumps can be built with features that
minimize releases, and tanks can be used as an
alternative to liners.
These practices generally afford more protection
than systems that allow disposal of tank bottoms,
produced waters, and other wastes in unlined pits
or on the ground (Walker et al 2007).
Discharges to Surface Waters
Discharges to surface waters are permitted under the environmental limit:
1) Into coastal or tidally influenced waters;
2) For produced waters from stripper oil wells to surface streams; and
3) For agricultural and wildlife beneficial use.
Treatment often occurs before discharge to control pH and to minimize oil
and grease, total dissolved solids, sulfates, and other pollutants. Radiation and
benzene or other organic chemicals presence.
To minimize generation of oil contaminated storm-water runoff primarily
includes the following measures:
Application of effective spill prevention and control;
Secondary containment procedures implementation to avoid
accidental or intentional releases of contaminated containment fluids;
Installation of stormwater channels and collection ponds with
subsequent treatment through oil / water separators. Oil / water separators
should be properly selected, designed, operated, and maintained.
Discharges to Surface Waters
The mixing of hazardous wastes with non-hazardous or exempt oil and gas wastes is
not recommended by EPA to some types of “recycling” (EPA, 1984). According to an
analysis by Amoco Corp., the method of basic waste minimization can potentially
reduce the volume of drilling fluids, including cuttings, by more than 60 % (API,1996).
EPA estimated that “closed-loop systems” can reduce the volume of drilling fluids by as
much as 90 %. (API, 1994). Closed-loop systems use mechanical solids control
equipment (e.g., screen shakers, hydroclones, centrifuges) and collection equipment
(e.g., vacuum trucks, shale barges) in minimizing the drilling waste muds and cuttings
that require disposal and maximizing the volume of drilling fluid returned to the drilling
mud system.
EPA and API indicate that fluids in some reserve pits contain lead, chromium, and
penta-chlorophenol at hazardous levels; and oil-based fluids may contain benzene. It is
possible to reduce the toxicity of drilling fluids. These components can potentially be
reduced or eliminated.
Training on waste management for contracted service providers should not be left to
installation managers on production platforms and vessels. Offshore waste procedures
often different to those onshore must be instilled beforehand by the service provider.
Full segregation at source should be nurtured at all production facilities.
Techniques for treating industrial process
for separation of oils and floatable solids; flow and load equalization; filtration for
separation of filterable solids; sedimentation for suspended solids reduction using
clarifiers; biological treatment, typically aerobic treatment, for reduction of soluble
organic matter (BOD); chlorination of effluent when disinfection is required;
chemical or biological nutrient removal for reduction in nitrogen and phosphorus;
and dewatering and disposal of residuals in designated hazardous waste landfills.
Typical wastewater treatment steps include:
Grease traps,
Skimmers,
Dissolved air floatation, or
Oil / water separators
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