Update on Developing and Commercializing Oil Herders for In-Situ Burning

Abstract

ABSTRACT Since the 2011 Conference (Buist et al. 2011 and Buist and Nedwed 2011), work on advancing oil herding agents for in-situ burning (ISB) has focused on three areas:Obtaining regulatory approvals for their use in North America;Developing an application system for use in a helicopter; and,Researching the effectiveness of herders for rapid-response ISB in open water. Desmi-AFTI worked in conjunction with S.L. Ross Environmental Research to get approval to use herders in North American waters. The proscribed test data from an accredited laboratory in Louisiana on three candidate herding agents (also called surface collecting agents) was submitted to the U.S. EPA for approval to list them on the National Contingency Plan (NCP) Product Schedule. Two herders have been placed on the list and are now commercially available. These two can be used, with the FOSC's concurrence, for spill response operations in U.S. waters. Samples of all three herders have been sent to Environment Canada, along with all the EPA test data, for their consideration. Quantities (200 L) of the two herders listed on the NCP Product Schedule have been produced and are stockpiled at Desmi-AFTI in Buffalo, NY. An application system, consisting of a pump, controls and reservoir has been designed to be placed inside an appropriate helicopter. It incorporates a reel-able hose that is used to lower the application nozzle to the correct height above the water for herder application. Dry land, static trials were conducted in September 2013 and helicopter flight trials are planned for summer and fall 2014. A back-pack sprayer system for herder application from a small vessel is available off-the-shelf, with only minor modifications required for cold-temperature use. The US Department of the Interior's Bureau of Safety and Environmental Enforcement sponsored a series of laboratory and Ohmsett experiments to see whether herders could contract oil slicks in wave conditions in open water. The results showed that the monolayer of each of the two best herders will survive for more than 45 minutes in a calm sea. The presence of breaking or cresting waves rapidly disrupts the herder monolayer and the oil slick resulting in the production of many small slicklets from the herded slick and the re-spreading of the oil to thin slicks. The monolayer survives for considerable periods of time in a swell condition, but the constant stretching and contracting of the herded slick results in elongating the oil slick and slowly breaking the slick into smaller segments. Testing of the helicopter application system with a herding agent on a 10 m3 experimental crude oil release in drift ice is planned for spring 2015. Further laboratory study of the approved herders is also planned with the goals of better understanding their toxicity and biodegradation and the window of opportunity for their effective use on weathered, emulsified and waxy oils.