When marine oil spills occur, response officials cooperate to minimize environmental impact. Objectives for on-water operations include preventing oil or debris from migrating to the shore, removing oil from the water, and minimizing overall environmental intrusion.
Ironically, cleanup operations themselves can generate waste and environmental impact, such as:
- contaminated sorbents used in the containment/collection effort,
- contaminated personal protective equipment,
- floating trash that comes into contact with oil.
Waste Makes Waste
Objectives for minimizing net environmental impact should include reducing the amount of solid waste from boom and sorbents, reducing the amount of liquid waste from decontamination and on-water recovery, reusing cleanup equipment and resources, and recycling recovered oil. Today's picture shows an on-site example of excessive use of soft boom during a waterfront remediation project. Once discovered, the USCG assisted contractors toward creating a static hard boom containment.
Waste segregation. Consciously keeping different waste types separated during a response can ensure that response actions minimize the amount of hazardous waste, and careful management of waste streams can increase the opportunity to recycle and/or reuse materials.
Decanting. The idea behind decanting is to separate oily water using the chemical properties of the oil. The oily water is left in a tank to separate, then water is removed until only the oil layer remains. This method greatly reduces the volume of liquid that requires treatment.
Reducing and reusing sorbents and booms. It takes discipline and understanding to decide how much sorbent to put in the water. Another option is to use hard boom for collecting oil. Hard boom is designed for reuse but requires decontamination (with water). So although the solid waste volume is reduced, this option can increase the liquid waste volume.
Personal protective equipment. Human health and safety is the number-one priority during any spill response. Although safety specialists conduct hazard assessments to determine the appropriate level of personal protective equipment, many responders have a “more is better” mentality. When additional personal protective equipment is not actually necessary to provide protection, it may cause more environmental damage.
Beach clean-up. When oil hits the shoreline, all of the trash and organic material that comes into contact with it must be treated as hazardous waste. Picking up trash on beaches before the oil can migrate there reduces the total amount of hazardous waste.
Reprocessing, incinerating, and recycling recovered oil. Liquid-recovered oil is not easy to reprocess, given the large amount of debris that is usually entrained in it. Some refineries can process recovered oil, but usually only do so if the spill involves them or occurs on their property. Even so, solid wastes must be incinerated or disposed of at a hazardous waste site.
Another option is to send recovered oil to a waste recycling facility. This costs between 25 cents to a dollar per gallon, depending on how much contamination the recovered product contains.
Dispersants, in-situ burning, bioremediation. Dispersants are chemicals applied directly to the spilled oil to remove it from the water surface. The idea is to break down the oil into small enough particles that they are diluted into the water column and are biodegraded easier. With in-situ burning, the tradeoff is that the contamination moves into the air in the form of particulates and smoke. Bioremediation uses micro-organisms to break down the oil through natural processes. This can take a very long time, and its effectiveness is still being studied.
For more information:
Full article and “Environmental Protection” edition of USCG Proceedings is available at www.uscg.mil/proceedings. Click on “archives” and then "2008-09 Volume 65, Number 4" (Winter 2008-09).
Subscribe online at http://www.uscg.mil/proceedings/subscribe.asp.
Direct requests for print copies of this edition to: HQS-DG-NMCProceedings@uscg.mil.