Oil Spills Control & Management

SUBMITTED BY-SHAMSHUL ARFEEN (BT13CIV049)BIVESH KUMAR (BT13CIV047)

What is an oil spill?

Oil spill is a type of pollution that occurs mostly on water as well as on land and can have devastating effects on plant and animal life, and the environment.

It occurs mainly as result of human activity (exploration and transport of oil) and is the release of oil/liquidpetroleum hydrocarbon into the aquatic environment such as oceans and coastal waters and on land.

Spills may occur of crude oil (unrefined oil) from tankers, oil rigs and platforms and oil wells as well as during the transport of the refined petroleum product in vessels and tankers.

Illegal waste oil dumping into oceans by organizations. Natural disasters

• For example, in the oil spill accident happened to a drilling platform named Deepwater Horizon in Mexico in April 2010, about 700,000 tons of crude oil leaked.

Deepwater horizon platform sinking(Source : US coast guard)

Effects of oil spills- On Human Health-

People's health could be adversely affected by oils either when inhaling or touching oil products, or when eating contaminated sea food.

The Braer oil spill (1993) People living in a 5 kilometer radius 1 to 2 weeks after the oil spill had a high

prevalence of headache, throat irritation, dermatitis, and itchy eyes. DNA adducts and other genetic abnormalities in local residents after the accident were

found.

On marine life-

Oil on ocean surfaces is harmful to many forms of aquatic life because it prevents sufficient amounts of sunlight from penetrating the surface.

It also reduces the level of dissolved oxygen.

Crude oil ruins the insulating and waterproofing properties of feathers and fur, and thus oil-coated birds and marine mammals may die from hypothermia.

Ingested oil can be toxic to affected animals. It can damage to their habitats.

It may affect their reproductive rate and affects their population for a long period. It also affects the food chain.

Effect on Industries-

It affects the fishing, shrimping and oyster Industries. It affects the tourism industries. It destroys the natural beauty.

Air pollution is also caused by oil spills by its burning.

Causes of oil spills- Oil spill pollution can have multiple causes both of natural as well as man made. Accidental spills- Storage – oil and oil products may be stored in a variety of ways including

underground and aboveground storage tanks such containers may develop leaks over time.

Handling – during transfer operations and various uses. Offshore drilling Routine maintenance activities such as cleaning of ships may release oil into

navigable waters. Water Sports -oil spills are spills by petroleum users of released oil. This happens

when various water sports or water vehicles such as motorboats and jet skis leak fuel. Intentional oil discharges

Oil spills in India-S.NO. DATE Qty. Place Spilled by1. 07/08/10 600 Tons

(Approx)Mumbai MV Chitra

2. 20/07/10 80 Tons Panna Offshore,Near Panna SBM

PMT JoinVenture

3. 12/04/10 08 -10 Tons Gopalpur (Orissa)

MV Malvika

4. 09/09/09 200-500 Ltrs Paradip PortAnchorage

MV Black rose

5. 19/07/2009 50 litres Off Mangalore

MV Asian Fores

Source-http://www.indiancoastguard.nic.in

Monitoring of oil spills-

Selecting the Sampling Location. The basic aim of a sampling design is to ensure field samples are representative of the area. There are three basic approaches-

Authoritative or Selective Sampling- This sampling is deliberately biased to specific

areas, e.g. visibly oil-free and oil-impacted sites.

Random Sampling- This is a more scientifically valid

method but usually requires a large number of sample locations.

Systematic Sampling

This sampling area uses a grid or consistent pattern across the defined area. This approach is most suitable when looking for non-obvious contaminated locations, such as subsurface oil.

Sample Handling Samples must be handled in such a way as to ensure that they remain uncontaminated, unspoiled by decomposition , breakdown or separation

Monitoring by radar-

• Large spills of oil related petroleum products in the marine environment can have serious biological and economic impacts.

• Remote sensing is playing an increasingly important role in oil monitoring.

• Synthetic Aperture Radar (SAR) satellites are usually used to monitor the sea oil spill.

• It is a more effective tool, which can penetrate clouds, rain and snow, less restricted by the weather.

• Microwave beam is emitted by the sensor, and the received signal is reflected by the object.

Framework of Oil Spill Monitoring Based on SAR Images-

speckle noises must be considered.

SAR instruments have the advantage over optical sensors that they can acquire images of the oceans and coastal areas day and night and despite any weather conditions.

Oil slicks are visible only for a limited range of wind speeds.

the wind level influences the backscatter level and the visibility of slicks on the sea surface.

• Prevention of oil spills

Double-hulling - build double hulls into vessels, which reduces the risk and severity of a spill in case of a collision or grounding. Existing single-hull vessels can also be rebuilt to have a double hull.

Secondary containment - methods to prevent releases of oil or hydrocarbons into environment.

Blowout Preventer

Making shipping safer

Keeping the navigator informed

Oil spill control technologies

Mechanical Containment and Recovery is the primary line of defense against oil spills. Containment and recovery equipment includes a variety of booms, barriers, and skimmers, as well as natural and

synthetic sorbent materials. Mechanical containment is used to capture and store the spilled oil until it can be disposed of properly.

Booms-

• Containment booms are used to control the spread of oil to reduce the possibility of polluting shorelines and other resources, as well as to concentrate oil in thicker surface layers, making recovery easier.

• In addition, booms may be used to divert and channel oil slicks along desired paths, making them easier to remove from the surface of the water.

Booms can be divided into several basic types-

• Fence booms have a high freeboard and a flat flotation device, making them least effective in rough water, where wave and wind action can cause the boom to twist.

• Round or curtain booms have a more circular flotation device and a continuous skirt. They perform well in rough water, but are more difficult to clean and store than fence booms.

• Non rigid or inflatable booms come in many shapes. They are easy to clean and store, and they perform well in rough seas. However, they tend to be expensive, more complicated to use, and puncture and deflate easily.

All boom types are greatly affected by the conditions on the water; the higher the waves swell, the less effective booms become.

Skimmers A skimmer is a device for recovering spilled oil from the water's surface. Three types of skimmers - weir, oleophilic and suction Weir skimmers use a dam or enclosure positioned at the oil/water interface. Oil floating on top of the

water will spill over the dam and be trapped in a well inside, bringing with it as little water as possible.

The trapped oil and water mixture can then be pumped out through a pipe or hose to a storage tank for recycling or disposal.

These skimmers are prone to becoming jammed and clogged by floating debris.

Oleophilic ("oil attracting") skimmers use belts, disks, or continuous mop chains of oleophilic materials to blot the oil from the water surface.

The oil is then squeezed out or scraped off into a recovery tank. Oleophilic skimmers have the advantage of flexibility, allowing them to be used

effectively on spills of any thickness. Some types, such as the chain or "rope mop" skimmer, work well on water that is

choked with debris or rough ice.

Suction skimmers operate similarly to a household vacuum cleaner.

Oil is sucked up through wide floating heads and pumped into storage tanks.

Although suction skimmers are generally very efficient, they are vulnerable to becoming clogged by debris and require constant skilled observation.

Suction skimmers operate best on smooth water, where oil has collected against a boom or barrier

Sorbents Sorbents are insoluble materials or mixtures of materials used to recover liquids through the

mechanism of absorption, or adsorption, or both. To be useful in combating oil spills, sorbents need to be both oleophilic (oil attracting) and

hydrophobic (water repellent). Although they may be used as the sole cleanup method in small spills, sorbents

are most often used to remove final traces of oil, or in areas that cannot be reached by skimmers.

Sorbents can be divided into three basic categories:

• Natural organic • Natural inorganic• Synthetic.

Natural organic sorbents include peat moss, straw, hay, sawdust, ground corncobs, feathers, and other readily available carbon based products.

Organic sorbents can adsorb between 3 and 15 times their weight in oil.

Natural inorganic sorbents consist of clay, perlite, vermiculite, glass wool, sand, or volcanic ash. They can adsorb from 4 to 20 times their weight in oil.

Synthetic sorbents include man made materials that are similar to plastics, such as polyurethane, polyethylene, and polypropylene and are designed to adsorb liquids onto their surfaces.

Other synthetic sorbents include cross linked polymers and rubber materials, which absorb liquids into their solid structure, causing the sorbent material to swell.

Most synthetic sorbents can absorb up 70 times their own weight in oil.

The characteristics of both sorbents and oil types must be considered when choosing sorbents for cleaning up oil spills:

• Rate of absorption - The absorption of oil is faster with lighter oil products. Once absorbed the oil

cannot be re released. Effective with light hydrocarbons (e.g., gasoline, diesel fuel, benzene).• Rate of adsorption - The thicker oils adhere to the surface of the adsorbent more effectively.

• Oil retention - The weight of recovered oil can cause a sorbent structure to sag and deform, and when it is lifted out of the water, it can release oil that is trapped in its pores. Lighter, less viscous oil is lost through the pores more easily than are heavier.

• Ease of application - Sorbents may be applied to spills manually or mechanically, using blowers or fans. Many natural organic sorbents that Sorbents being used to absorb crude oil. exist as loose materials, such as clay and vermiculite, are dusty, difficult to apply in windy conditions, and potentially hazardous if inhaled.

Chemical and Biological Methods

•Chemical and Biological Methods can be used in conjunction with mechanical means for containing and cleaning up oil spills. Dispersing agents and gelling agents are most useful in helping to keep oil from reaching shorelines and other sensitive habitats. Biological agents have the potential to assist recovery in sensitive areas such as shorelines, marshes, and wetlands.

•Dispersing Agents

oDispersing agents, also called dispersants, are chemicals that contain surfactants and/or solvent compounds that act to break petroleum oil into small droplets.

oIn an oil spill, these droplets disperse into the water column where they are subjected to natural processes, such as waves and currents, that help to break them down further.

oThis helps to clear oil from the water's surface, making it less likely that the oil slick will reach the shoreline.

oHeavy crude oils do not disperse as well as light to medium weight oils.

EX- Alkylphenol, 2-Butoxyeyhanol

DISPERSANT USE FLOWCHART

Gelling Agents

• Gelling agents, also known as solidifiers, are chemicals that react with oil to form rubber like solids.

• With small spills, these chemicals can be applied by hand and left to mix on their own. For treating larger spills, the chemicals are applied to the oil, then mixed in by the force of high pressure water streams.

• The gelled oil is removed from the water using nets, suction equipment, or skimmers, and is sometimes reused after being mixed with fuel oil.

• There is one drawback to the use of gelling agents. Large quantities of the material must often be applied, as much as three times the volume of the spill. For oil spills of millions of gallons it is impractical to store, move, and apply such large quantities of material.

Biological Agents

• Biological agents are chemicals or organisms that increase the rate at which natural biodegradation occurs.

• Biodegradation is a process by which microorganisms such as bacteria, fungi, and yeast break down complex compounds into simpler products.

• Biodegradation of oil is a natural process that slowly sometimes over the course of several years removes oil from the aquatic environment.

• Bioremediation technologies can help biodegradation processes work faster.

• Bioremediation refers to the act of adding materials to the environment, such as fertilizers or microorganisms, that will increase the rate at which natural biodegradation occurs.

• Two bioremediation technologies that are currently being used –

• Fertilization

• Seeding

• Fertilization, also known as nutrient enrichment, is the method of adding nutrients such as phosphorus and nitrogen to a contaminated environment to stimulate the growth of the microorganisms capable of biodegradation.

• When more nutrients are added, the native microorganism population can grow rapidly, potentially increasing the rate of biodegradation.

• Seeding is the addition of microorganisms to the existing native oil degrading population.

• Sometimes species of bacteria that do not naturally exist in an area will be added to the native population.

Other Response Techniques

• Physical methods are used to clean up shorelines. Natural processes such as evaporation, oxidation, and biodegradation can start the cleanup process, but are generally too slow to provide adequate environmental recovery.

• Scare tactics are used to protect birds and animals by keeping them away from oil spill areas. Devices such as propane scare cans, floating dummies ,and helium filled balloons are often used, particularly to keep away birds.

• Controlled burning is also another approach that has been used to clear out oil spillages but it brings about air pollution issues.

• The use of a centrifuge has been commonly employed and works by sucking up oil and water after which the oil is separated from the water and the water pumped back into the ocean.

• And the last approach is to do nothing and let nature take its course. This is actually a remediation approach and is regarded to as natural attenuation.

Management and disposal of oil spill debris

• Oil collected from the surface of the sea can contain debris such as seaweed, wood, plastic materials of various types, dead birds and animals.

• Collection and disposal are greatly complicated by the variation in waste composition and appropriate disposal techniques have to be selected for the particular circumstances.

• When removing sand or structural material from a beach it should be remembered that a minimum volume should be taken to preserve the integrity of the beach and to minimise the volume of waste requiring disposal.

• Disposable overalls and gloves oiled in the cleanup effort should be wiped at the end of each day with rags dipped in kerosene and reused. The rags and the items themselves may be disposed of to landfill as solid oily waste.

• The type and volume of waste will depend upon the size and location of the spill and the clean-up methods employed.

Conclusion –

Oil spill is a type of pollution.

It is injurious to environment therefore a proper treatment should be used for its cleaning.

Different cleaning techniques have different characteristics and it should be used according to that.

Proper monitoring of oil spills should be done over a period of time and also after its cleaning.

Oil transportation should be done in a secure manner.

Oil debris should be handled proprely.

References-

• Oil Spill Monitoring based on SAR Remote Sensing ImageryJianchao Fana, Fengshou Zhangb, Dongzhi Zhaob, Jun Wanga

• OIL SPILL MONITORING HANDBOOK- Australian Maritime Safety Authority

• Oil spill control technologies - Mallory Nomack (EPA)

• GUIDELINES FOR THE USE OF OIL SPILL DISPERSANTS - Leigh Stevens (Cawthron Institute- New Zealand)

• Encyclopedia Britannica www.britannica.com

• www.indiancoastguard.nic.in

• Oil Spill Prevention and Response Guidance -California Coastal Commission

• Effects of Oil on Wildlife and Habitat - U.S. Fish & Wildlife Service

• http://www.epa.gov/emergency-response/sorbents