WATER POLLUTION IN PETROLEUM INDUSTRY

Water Pollution

Water pollution can be defined as presence of solid, liquid or gaseous contaminants in such concentration that may alter the quality of water.

Water pollution is defined as the addition to water of an excess material or heat that is harmful to the living organism or which impairs the beneficial use of water.

WATER POLLUTION

The principal sources of water pollution resulting from exploration and production operations are :

1. Produced Water.

2. Drilling fluids, Cuttings and well treatment chemicals.

3. Process, wash and Drainage water.

4. Sewerage, sanitary and domestic wastes.

5. Spills and leakages and

6. Cooling water.

Volumes of waste produced depend on the stage of the exploration and production process.

During seismic operations, waste volumes are minimal and relate mainly to vessel activities.

In exploratory drilling the main aqueous effluents are drilling fluids and cuttings.

In production operations – after the development wells are completed – the primary effluent is produced water.

Oil based drilling fluids and cuttings on the other hand have an increased effect due to its toxicity.

Ocean discharges of water-based mud and cuttings have been shown to affect benthic organisms.

Oil based mud and cuttings affect benthic organisms.

The high pH and salt content of drilling fluids and cuttings poses a potential impact to fresh-water sources.

Other aqueous waste streams such as leakage and discharge of drainage waters may result in pollution of ground and surface waters.

Produced WaterWater coming out from reservoir, is separated

from the oil and gas in the production facility.The produced water can be one of the largest

waste products, by volume, which needs to be managed and disposed off by the oil and gas industry.

Produced water contains a complex mixture of inorganic (dissolved salts, trace metals, suspended particles) and organic (dispersed and dissolved hydrocarbons, organic acids) compounds.

Feasible alternatives for the management and disposal of produced water should be evaluated and integrated into production design.

The main disposal alternatives may include:

(a) injection into the reservoir to enhance oil recovery

(b) injection into a dedicated disposal well drilled in a suitable subsurface geological formation.

Produced water discharging to surface waters or to land should be the last option considered and only if there is no other option available.

Discharged produced water should be treated to meet the guidelines.

Disposal into evaporation ponds may be an option for produced waters.

Emissions, Effluent & Waste Levels from Onshore oil & Gas Development

Parameter Guideline Value

.Produced Water

For discharge to surface waters or to land Total HC content : 10mg/l pH : 6 – 9 BOD: 25mg/l COD: 125mg/l TSS: 35mg/l Phenols : 0.5mg/l Sulfides : 1mg/l Heavy metals : 5mg/l Chlorides : 600mg/l (average) & 1200mg/l ( maximum)

Parameter Into In Land Surface Water

Into Marine Coastal Area

Suspended Solids(mg/l)

Particle size of suspended solids

100

Shall pass 850 micron IS Sieve

(a) For process waste water -100

(b) For Cooling water effluents 10% above T-suspended matter of influents cooling water.

(a) Floatable solids max.3mm

(b) Settlable solids max.850 microns

Indian Standards for Industrial Effluents

Parameter Into In Land Surface Water

Into Marine Coastal Area

Dissolved solids (Inorganic) mg/1 max.

pH value

Temperature C

Oil & Grease mg/1 max.

Total Residual Chlorine mg/1 suspended solids

2100

5.5 to 9

Shall not exceed 40 in any section of the stream within 15 mts. down stream from the effluents outlet

10

1

shall pass 850 micron IS Sieve

_

5.5 to 0 45 at the point of

discharge

20

1

Indian Standards for Industrial Effluents

Parameter Into In Land Surface Water

Into Marine Coastal Area

Ammoniacal Nitrogen (AsN) mg/1 max.

Free amonia

Biochemical oxygen demand

Chemical oxygen demand mg/1

Arsentic mg/1

Mercury mg/1

50

5

30

250

-2

0.01

50

5

100

250

-2

0.01

Indian Standards for Industrial Effluents

Parameter Into In Land Surface Water

Into Marine Coastal Area

Lead (mg/1)

Cadmium mg/1

Chromium mg/1

Copper mg/1 Zinc mg/1

Selenium mg/1

Nickel mg/1

Boron mg/1

0.01

2

2

3

5

0.05

3

2

1

2

2

3

15

0.05

5

_

Indian Standards for Industrial Effluents

Parameter Into In Land Surface Water

Into Marine Coastal Area

Percent sodium

Cyanide mg/1

Chloride mg/1

Fluroride mg/1

Dissolved phosphate mg/1

Sulphate mg/1

Sulfide mg/1

Phenolmg/1

_

0.2

1000

2

5

1000

2

1

60

0.2

_

15

_

_ 5

5

Indian Standards for Industrial Effluents

Drilling Fluids and Drill CuttingsThe primary functions of drilling fluids used in

oil and gas field drilling operations include removal of drilled cuttings (rock chippings) from the wellbore and control of formation pressures.

Other important functions include cooling and lubricating the drill bit, and transmitting hydraulic energy to the drilling tools and bit.

Drilled cuttings removed from the wellbore and spent drilling fluids are typically the largest waste streams generated during oil and gas drilling activities.

Feasible alternatives for the treatment and disposal of drilling fluids and drilled cuttings should be evaluated and included in the planning for the drilling program. Alternative options may include one, or a combination of, the following:

Injection of the fluid and cuttings mixture into a dedicated disposal well. Storage in dedicated storage tanks or lined pits prior to treatment, recycling, and / or final treatment and disposal.

Final disposal routes for the nonhazardous cuttings solid material should be established, and may include use in road construction material, construction fill, or disposal through landfill including landfill cover and capping material where appropriate.

Sewage & Process DrainageIs the process of removing contaminants from

wastewater, both runoff and domestic. It includes physical, chemical and biological processes to remove physical, chemical and biological contaminants.

Its objective is to produce a waste stream (or treated effluent) and a solid waste or sludge also suitable for discharge or reuse back into the environment. Sewage can be treated close to where it is created (in septic tanks or on site package plants and other aerobic treatment systems), or collected and transported via a network of pipes and pump stations to a municipal treatment plant.

Wastewater TreatmentTypically, sewage treatment involves three stages, called primary, secondary and tertiary treatment. First, the solids are separated from the wastewater stream.

Then dissolved biological matter is progressively converted into a solid mass by using indigenous, water-borne bacteria.

Finally, the biological solids are neutralized then disposed of or re-used, and the treated water may be disinfected chemically or physically (for example by lagoons and micro-filtration).

Oil Spill Control & Prevention

Presented By:Arpit Atreya (09)Ankur Bajpai (10)Nirmal Chandran (11) 23

What’s an oil spill?

When oil of any type is released into the natural environment, the result is termed an oil spill.

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Effects of Oil Spills-Environmental effects

Because oil floats on top of water, less light penetrates into the water, limiting

the photosynthesis of marine plants and phytoplankton. This, as well as

decreasing the fauna populations, affects the food chain in the ecosystem.

Oil destroys the insulating ability of fur-bearing mammals, such as sea otters,

and the water-repelling abilities of a bird's feathers, thus exposing these

creatures to the harsh elements.

Many birds and animals also ingest (swallow) oil when they try to clean

themselves, which can poison them. Depending on just where and when a spill

happens, from just a few up to hundreds or thousands of birds and mammals

can be killed or injured.

The effects of Exxon Valdez oil spill can be seen even now, after 20 years the

incident took place.

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How do they clean up the oil on the beaches or the water after a spill?

The Oil that gets washed up on

the shores are mechanically

cleaned by Humans. The oil is

first absorbed using sorbents.

Then the remaining parts are

cleaned using shovels. The

residual parts are then allowed to

break up naturally or biological

agents are used to decompose

them to carbon dioxide and other

less toxic components

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Tools for controlling Oil Spills

Mechanical:-Booms: large floating barriers that round up oil and lift the oil off the water

Skimmers: skim the oil

Sorbents: large absorbents that absorb oil

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Contd…..Chemical:-Chemical and biological agents:

helps to break down the oilVacuums: remove oil from beaches

and water surface

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