May 4, 2010

The Gulf Oil Spill: Cleanup


Spill Update:

Estimates of the quantity that has spill thus far tend to vary greatly. But the most consistent estimate is that 5,000 barrels of crude oil, a day, are being released into the Gulf. That brings us to at least 2.5 million gallons now and rising. New concerns are leading toward the spill getting pushed around the tip of Florida by the Gulf Stream and then up the Eastern Seaboard.

Cleanup Strategies:

So far the main cleanup strategies used to try and mitigate the spread of oil in the Gulf has been the use of booms, absorbent material and water skimmers, chemical dispersants and even controlled burns.

Booms tend to work very well at containing spreading oil, on the surface of water, when the water is fairly calm. However, this has not been quite the case so far in the Gulf of Mexico, not to mention the fact that this oil is being released from approximately 4500 feet below the surface of the water and since oil is lighter than water is naturally rises, however it does not all rise to the surface in the same place. Further, oil has a tendency to spread out on the surface of water. These characteristics combined with the extremely large area of water known as the Gulf of Mexico are making booms a less than ideal way to mitigate the spread of oil.

Absorbent material and skimmers are being deployed which physically remove oil from the water. These methods are very useful in cleaning/removing rather thick puddles of oil, but are rather fruitless in trying to clean up thin, dispersed oil sheens. Sheens are what is observed as oils spreads on the surface of water, typically making iridescent or rainbow colors. In fact, there have been news reports indicating that hair is an effective sponge, and being as such hair donations from hair salons around the country are being donated, hair drives are being conducted, etc to try and aid in cleanup efforts. (see article)

Chemical dispersants have by far been the most sought after solution to prevent impacts to shorelines. In fact, it is estimated that BP has deployed over 100,000 gallons of dispersants already both on the surface of the water and at depth near the physical oil well. “Dispersants are mixtures of solvents, surfactants and other additives that break up the surface tension of an oil slick and make oil more soluble in water, according to a paper published by the Natinal Academy of Science. They are spread over or in the water in very low concentration – a single gallon may cover several acres. Once they are dispersed, the tiny droplets of oil are more likely to sink or remain suspended in deep water rather than floating to the surface and collecting in a continuous slick. Dispersed oil can spread quickly in three directions instead of two and is more easily dissipated by waves and turbulence that break it up further and help many of its most toxic hydrocarbons evaporate.” (see article)


Finally, controlled burns have been tested by the coast guard, as a potential cleanup strategy, on some of the thicker puddles of oil that they have been able to corral in booms, however to be effective as a cleanup method the puddles have to be somewhat substantial as opposed to the more common sheens or thinner, more spread out oils slicks.


Long Term Solutions

So far BP has come up with 2 long term solutions to mitigate the oil spill. The first is to place a concrete and steel cone over the well and funnel the leaking oil to the surface and have it loaded on ships while a more permanent solution is reached. This funnel option is estimated to take an additional week to complete and install, by which time another 1.5 million gallons of oil will have been released into the gulf. The more permanent solution is to drill an alternate well into the existing leaking well, and capping the leaking well using mud and concrete. This drilling option has already begun, with assistance from Transocean, the company operating the Horizon oil rig which sunk causing the oil spill. However, this option may take up to 3 months to complete.

Conclusions:


Mitigation of this spill will be what determines how destructive it is to the environment, fisheries, the people who live in and around the Gulf of Mexico, the shorelines affected and the oil industry as a whole. If you read the articles linked to this post you will find that while there are pros and cons to each strategy, ultimately stopping the leak is the real solution. The short term strategies are not very effective at containing a spill of this magnitude, in this setting. The use of dispersants is kind of troubling to me. While they aid in removing the physical oil slick, they end up putting that oil into suspension in the water column, and eventually the sediments of the ocean floor putting them in greater contact with marine life, shell fish, filter feeders, and on and on. Furthermore, the effects of the use of those surfactants and dispersants on the aquatic ecosystems is largely unknown, and ingredient lists are held as trade secretes. Make you wonder what is actually going on, or at least it makes me wonder. Who knows they may be doing more harm then good and we wont know this for years potentially. So best case scenario, this sounds strange to me but, we have around one additional week of oil spilling into the Gulf of Mexico at 5,000 barrels a day (210,000 gallons/day). I guess we will just have to wait and see.


For more information, actual numbers as they are being made public, clean up measures, pictures of the events visit: http://www.deepwaterhorizonresponse.com/go/site/2931/





No comments:

Post a Comment