Main Techniques for Cleaning-Up Oil Spills - Report Example

Main Techniques for Cleaning-Up Oil Spills Teacher’s School Contents 2. General outline of Response Techniques 3. Containment and Recovery 4. In-Situ Burning 5. Dispersants 6. Bioremediation 7. Shoreline Clean-Up 8. Conclusions 9. References Abstract Effects of an oil spill may be rather harmful, both for the environment and human health. For this reason, oil response techniques are of vital importance. There is a number of response mechanisms which give coast guard and clean-up workers an opportunity to control oil spills and minimize their negative effects. If to talk about the widest-spread response mechanisms, it is necessary to mention mechanical containment and recovery – oil is physically removed from the sea surface. One more method, chemical, presupposes the use of dispersants and other chemical substances. Among these methods there is also bioremediation, one of the most eco-friendly approaches. It is very essential and often difficult to find the most appropriate type of response techniques. It is impossible to say that there is a universal method which may be applied under any circumstances. The choice of techniques is always predetermined by area specificity, weather conditions, type of oil, and so on. In some cases it is impossible to apply a technique which would work best under other circumstances. Thus, each technique has its own strengths and limitations. Very often, however, the best option is to combine a couple of techniques as they are able to reinforce each other. Key words: oil spill, response techniques, mechanical containment, dispersants, bioremediation. Main Techniques for Cleaning-Up Oil Spills General outline of Response Techniques Accidental oil spills, usually the result of human activity, inflict sufficient and often permanent damage to the environment, which is very hard to heal. Like any other kind of ecological disasters, oil spills exert powerful economic and social effects, too. To clean up an oil spill often means to take part in a race against time. The slower the response is, the worse consequences should be expected. For this reason, oil spill response techniques are vitally important, especially under conditions of dynamic development of oil industry. Quite many of them may be mentioned, though none is a universal remedy. The larger the spill is, the harder it is to handle. The choice of techniques usually depends on characteristics of the spill and area it occurs in. It is predetermined by the type and amount of oil spilled, water temperature, and shorelines. Talking about best methods for cleaning up oil spills, it is worthy to mention bioremediation, which seems to be one of the most effective and eco-friendly approaches. In most cases, however, combination of different methods yields the best results. It is necessary to take into consideration that the spill will definitely spread under the influence of waves, wind, and undercurrents. In addition, oil usually tends to drift towards the shore. As a rule, the choice of techniques is predetermined by the distance between the spill and the shore. Time is a decisive factor too. In case it is necessary to respond to the spill at sea, clean-up workers usually apply containment and recovery, in-situ burning, and dispersants. When it comes to shoreline clean-up, it is usually conducted by the citizen volunteers and do not require specialised equipment.   Containment and Recovery One of the most eco-friendly methods of dealing with spilled oil, adopted in many countries worldwide, is to contain it into booms. In other words, oil is physically removed from the sea surface by skimmers, specialized machines which remove floating oil. Unfortunately, this technique is quite difficult to apply. Only approximately 10-15% of oil may be recovered from the water surface (ITOPF 2014). First of all, weather and the sea state should be relatively calm, otherwise response equipment cannot function normally. Secondly, the state of the spilled oil is often unamenable for recovering. Time is also an important factor. Containment and skimming may only be used within a couple of hours after the spill. That is when the first, mechanical wave of clean-up starts. Besides, this kind of equipment is supposed to be immediately accessible, though it may not always be so in practice. One more effective measure is to place booms. As a rule, they are situated close to the coast. Booms serve like a barrier past which the oil cannot pass. Besides, some booms may also absorb the oil. When wind and waves are up, however, booms are also difficult to deploy. Thus, containment and recovery are good when applying within the first hours after a spill, in case response factors are favourable. In-Situ Burning Among the most effective and widely-used methods to deal with oil spills there is controlled burning, also known as in-situ burning. It is especially effective when the spill is fresh and the weather is comparatively calm. The main idea is to corral the oil slick into a fire-proof boom and set it on fire. In case this procedure is conducted properly, it significantly reduces the amount of oil on the water and lessens its harmful effects on the environment (OR&R 2015). In situ-burning, however, has a number of disadvantages, too. It produces toxic smoke, and therefore should not be used near coastal settlements. Nevertheless, this drastic action has been taken by the US Coast Guard, in their attempts to localize the oil spill in the Gulf of Mexico in 2010. According to the studies by NOAA, the amount of black smoke is roughly equal to the total black carbon emissions normally released by all ships that travel the Gulf of Mexico during a 9-week period (OSS, 2013). Apparently, it is necessary to find greener alternatives. Dispersants Another wide-spread method is dispersants, used in order to dissipate oil slicks. This technique is especially beneficial in case effectiveness of other response methods is limited due to weather conditions or resource availability. Dispersants are able to remove significant amounts of oil from the sea surface. They transfer oil into the water column, where it is eventually breaking down due to natural processes. The mechanism is as follows: the surface oil slick is supposed to be broken up into droplets, at first. After this, most droplets remain suspended in the water column, where bacteria eventually degrade them. Thus, the main idea of this technique is to accelerate natural processes of oil dispersion. Dispersants, however, demonstrate low efficiency if the oil is too viscous. It should not be forgotten that weathering processes encourage it, that is why oil may become resistant quite in a short period of time. They are also ineffective when pour point of the oil is equal to the one of environment temperature (ITOPF 2014). Thus, dispersant effectiveness is often limited, that is why it is very important to monitor it on a continuous basis. It is essential to terminate the use of dispersants the moment they become ineffective. Dispersant use is sometimes controversial. It often becomes a hot topic of discussion in media. Opponents of this method insist that dispersants may only become one more source of pollution which poses additional threat to flora and fauna. Its advocates, in turn, try to prove that application of dispersants is sometimes the only way to minimize environmental impact of oil. This is true that dispersants, as well as dispersed oil particles, are harmful for many marine organisms. At the same time, they are exposed to harmful influence of dispersed oil for rather short periods of time (OR&R 2015). There is often a dilemma. On the one hand, dispersants sometimes provide an opportunity to avoid impacts on the shoreline. On the other hand, plankton, reef corals, and some other water column organisms may be damaged. That is why risks of decisions to use this technique should be thoroughly weighted in every particular situation. Nevertheless, a lot of coastal regions in the US include dispersant use in their plans of oil spill response. This is one of the options which may be exploited under certain conditions. At the same time, dispersants are still one of the main response techniques in the UK and Europe (OR&R 2015). Sea Empress oil spill, which occurred in Wales in 1996, may be a good example. The amount of oil spilled was approximately 10,000-15,000 tonnes. Foreshores could have been damaged quite badly unless dispersants had been used. It is necessary to remember that dispersants cannot eliminate the problem. They may only be used as a means to reduce overall effects of spill on the environment. To exploit this technique always means to make a sacrifice. In this case, the task of response authorities and scientists is to find out whether this sacrifice is truly worthy. Bioremediation Among other methods which provide worthwhile response there is the use of microorganisms, or bioremediation. Unfortunately, this method may only be used when the oil reaches shore. The mechanism of its work is quite simple. Naturally present organisms begin to consume oil the moment it appears in their natural habitats. It is also worthy to mention that oil-consuming bacteria are present in almost all coastal environments. The main idea of bioremediation is to add sulfate or nitrate fertilizers in order increase population of microorganisms. Water temperature may sometimes be a decisive factor. Low temperature always slows down the tempo of bacteria growth (Biello 2010). Unfortunately, that was the case with the Deepwater Horizon oil spill. The oil was reported at 800 to 1,400 meters depth. Nevertheless, the example of the Deepwater Horizon shows that bioremediation is especially effective when preceded by dispersants. The smaller oil droplets are, the more effective this technique is. As it was mentioned, dispersants break up oil into small droplets. Besides, as scientists assure, ‘dispersants can also stimulate microbial growth. Bacteria will chew on the dispersants as well as the oil’ (Biello, 2010) This technique was applied after the Exxon-Valdez spill along the Alaska coast. The project yielded good results. Bioremediation is currently acknowledged as one of the most effective methods to treat the shoreline on a continuous basis. At the same time, it is impossible to estimate efficiency of this method in each particular case over a short period of time. Nevertheless, environmental observations in the Gulf show that much oil disappeared faster than it was suggested at first. It is actually difficult to overestimate the role of oil-consuming bacteria in this case, even though there is still much oil left. Although bioremediation is often more effective, faster, and safer technique than many others, it has disadvantages too. Scientists assume that oil-consuming microorganisms, being eventually eaten by larger organisms, may introduce heavy metals into the food chain. Thus, there is a threat that these elements may one day reach human food, too. Shoreline Clean-Up Although this is quite a simple and direct method of response, it is often necessary to make considerable efforts in order to clean up contaminated areas. As a rule, this method involves straightforward techniques and do not require specialized equipment. Shoreline clean-up is often conducted by volunteers, living not far from contaminated areas. These are often ordinary people, that is why proper organization of the process is very essential. There is a big variety of shoreline clean-up techniques. It is very important to make the right choice of a technique, since it always predetermines success of the whole operation. The choice should be based on the stage of response and environmental factors. The best option is sometimes to use manpower, which is widely practiced in many countries. What is more, this is the only variant in case the shore is inaccessible to vehicles (ITOPF, 2014). It is also necessary to remember that oil on the shore is especially dangerous for wildlife habitats. For this reason, special attention should be paid to animals which suffered from oil pollution. In general, this methods is quite good, but difficult to apply. Besides, rates of progress of such progress are often slow due to poor organization. Conclusions It is possible to continue the list of techniques which may be applied in struggle with oil spills. Each of them has its own advantages and disadvantages, that is why it is often hard to define which one may turn to be most effective. The choice of techniques is always predetermined by response factors. Very often, the best variant is to combine different techniques. The main principle is not to do as much harm as the oil spill does. Although recovery efforts are usually rather extensive and well-funded, oil spills always leave their mark on the environment. It is hard to say how much time nature will need in order to recover after some of the oil catastrophes of the recent years. Their consequences may still be felt in a couple of decades. In this case, the only thing people may do is to wait. References Conservation Institute, 2015, Oil Spill Cleanup Methods: How Do You Clean Up An Oil Spill?. Available at http://www.conservationinstitute.org/oil-spill-cleanup-methods-how-do-you-clean-up-an-oil-spill/ David Biello, 2010, Slick Solution: How Microbes Will Clean Up the Deepwater Horizon Oil Spill. Available at http://www.scientificamerican.com/article/how-microbes-clean-up-oil-spills/ ITOPF, 2014, Response Techniques. Available at http://www.itopf.com/knowledge-resources/documents-guides/clean-up-techniques/ OR&R, 2015, What Are Dispersants?. Available at http://response.restoration.noaa.gov/oil-and-chemical-spills/oil-spills/resources/dispersants-guided-tour.html OSS, 2013, The various strategies used during an oil spill response. Available at http://www.oilspillsolutions.org/strategies.htm Read More