In this chapter the available information on response technologies is evaluated with respect to the likely efficacy of response in the six settings described in Chapter 2, namely, marine—open water; marine—nearshore; estuarine (brackish water); nontidal river; fresh water—quiescent; and on land near water. Most of the literature on response options for spills of emulsified fuels describes equipment and systems that are similar to those traditionally used to respond to spills but modified to have improved effectiveness for spills of emulsified fuels. However, because there have been no significant spills of emulsified fuels, the modified equipment and the strategies for their use have been untested in real cleanup situations. Therefore, no actual spill data for determining actual or measurable effectiveness are available. These response options and their modifications are evaluated to the degree possible in the following sections.

It should be noted that the effectiveness of oil response in containment and recovery of spilled oil has been historically low. In the response community, recovery of 20 percent of the spill volume is considered to be a good effort. Where dispersants or in situ burning are used effectively there is little or no additional response or recovery.

In recent years, alternative technologies have been accepted as response tools to be considered as part of the oil spill response arsenal in the United States. Alternative response technologies usually include, but are not limited to, the use of dispersants, in situ burning, and bioremediation. Since some emulsified fuels,

such as Orimulsion-400, already have a dispersant added in the form of their emulsifying surfactant, at the instance of spillage they disperse into the upper part of the water column. Therefore, the aerial dispersant application operations that are normally considered the first response in many areas of the United States for most spilled oils in the open water, have already taken place with emulsified fuel products.

Since 1989, BITOR and its subsidiaries, in conjunction with their primarily utility company clients and U.S. and international government agencies, have studied the response to and possible cleanup techniques for spills of Orimulsion-100 and Orimulsion-400. These studies provide a large volume of information regarding available cleanup techniques and the individual merits and failures of response for these emulsified fuel products. Table 4.1 summarizes the effectiveness of response options for spills of emulsified fuels in marine open-ocean environments. It is clear that in an open-water marine environment, the preferred response methodology would be to monitor the naturally dispersed bitumen plume using the Surveillance and Monitoring for Alternative Response Technology (SMART) protocols in place for monitoring chemically dispersed spills of other types of oil. This sampling and analysis approach could also be augmented with discrete water column sampling for separate dissolved and dispersed bitumen droplet phases (Payne et al., 1999), to provide calibration for the UV fluorescence approach of the SMART Protocols and validation of computer model predictions of dissolved- and dispersed-bitumen droplet PAH concentrations.

The availability of existing sophisticated computer three-dimensional modeling programs will support and enhance required surveillance operations (French et al., 1997). If any of the spill re-floated and was found, cleanup would be initiated using existing cleanup technology developed and available for Orimulsion, as well as technologies available for other Group V oils that are presently being transported in the United States (National Research Council, 1999).

Many of the tests for equipment specifically designed for response to spills of Orimulsion products have been carried out on the open-ocean to determine the ability of responders to recover dispersed bitumen in that environment (Hvidbak and Masciangioli, 2000). As is the case with most open-ocean oil spill response equipment, some equipment developed specifically for response to Orimulsion spills and evaluated during the documented tests, such as the Tar Hawg, the forced adhesion and floatation (FAF) system, the PNP Re-floater, and the deepskirted containment booms, can reasonably be deployed and perform to some degree of efficiency in calm, open-ocean conditions, especially during an intentional spill demonstration scenario (Bitor America Corporation, 1997). For persons not familiar with equipment that has been developed specifically for Orimulsion, the Tar Hawg is a belt skimmer that has teeth built into the belt to enhance bitumen adhesion. The FAF and PNP Re-floater systems are two different methods of pumping both water and Orimulsion from the dispersed plume and forcing air into the pumped material, causing the bitumen to float. As the

name suggests, the deep-skirted containment boom is a normal offshore-type oil spill containment boom with a 9- to 12-foot skirt. However, although responding to locate and recover any floating weathered bitumen is practical and reasonable, the notion that requiring an operation to be mounted with the goal of tracking, refloating, and then recovering a dispersed oil of any type in the open ocean would be unrealistic and unreasonable.

The disposal of recovered weathered bitumen poses the same problems as the disposal of other recovered crude oil and oil products that are spilled (Bitor America Corporation, 1999).

In the nearshore marine environment, the surveillance and monitoring response action (Table 4.2) suggested for the open ocean will be more important because of the increased potential for the bitumen to re-float in sticky clumps. Any re-floated bitumen will provide a threat to wildlife due to the greater number of birds and marine mammals present in the nearshore environment.

Furthermore, the potential for re-floated bitumen to come ashore as an oil slick or in the form of sticky tar patties and tar mats is much greater. Because shoreline cleanup is more costly and shoreline impacts increase the potential for natural resource and third-party damages, there should be an increased effort to respond to recover re-floated bitumen as quickly as possible.

The containment and recovery of re-floated “clumps” will follow the same strategy and, to a large degree, will use the same equipment available in the openwater marine environment. Response times should be faster for spills in nearshore waters, potentially increasing the effectiveness of on-water containment and recovery operations. If available, the viscous oil recovery equipment developed for Orimulsion may enhance the recovery rate for resurfaced Group V oil (Garcia Tavel et al., 1997). However, in order to make a difference, equipment such as the Tar Hawg, Oriboom, and other devices must be stockpiled in sufficient quantity at locations where the greatest potential for emulsified fuel spills exists (Middleton et al., 1995). Furthermore, local responders need to become familiar with the effective operation of this equipment. While existing equipment resources serving other oil transporters and storage facilities will satisfy the containment and recovery of resurfaced Group V oil requirements under the Oil Pollution Act of 1990 (OPA-90), especially if enhanced with the specially designed equipment for Orimulsion, the concern will be for the special on-water storage requirements necessary for these types of oils. It would seem that the viscosity of this product will mandate that all tank barges and tanks on skimming vessels be heated if off-loading of filled tanks is considered during a continuing on-water response operation.

Since there is greater potential for dispersed bitumen to re-float in the coastal zone, dispersants must be considered for this environmental scenario. Limited

studies have indicated that applying dispersant to re-floated bitumen will cause some redispersal (Oil Spill Response Limited, 1989). However, more work would have to be completed to determine if the dispersant application would be efficient and effective.

Shoreline protection and cleanup must also be considered in the coastal environment. For the most part, shoreline protection and cleanup of emulsified fuels will be conducted in the same manner as for other oil products (Owens and Sergy, 1999). There may also be a need to protect sensitive areas from shoreline impact if possible. Presumably this can be achieved by using long-skirted booms to exclude the oil from the zone to be protected, diverting it to a less sensitive shoreline for recovery or deflecting it back to open water (Morgan and Fernie, 1995; Owens and Sergy, 1999).

Once weathered bitumen is stranded on the shoreline, chemical agents enhance its removal (Guénette et al., 1998). However, further testing, particularly with agents accepted by the U.S. EPA for use in the United States, should be conducted to determine their efficiency in removing stranded bitumen coatings from various shoreline types and to study the fate and effects of the released bitumen.

As with other types of heavy oil, mechanized beach cleaners and other types of mechanical or manual recovery equipment are efficient in cleaning up stranded weathered bitumen from certain shorelines (Clement et al., 1997). Dredging or other types of underwater recovery must also be considered as a response option,

because oil-sediment tar mats may be deposited in offshore depressions. Again, these operations will be similar to those used for spills of other types of heavy oil (National Research Council, 1999).

Because of the increased potential for contact with wildlife cleaning, of seabirds particularly, will become an issue. Even though a suitable agent has been proposed for cleaning wildlife (Gauvry and Miller, 1995), the effect of weathered Orimulsion on wildlife and the ability to clean contaminated wildlife for return to their habitat remain to be seen.

The report by Gauvry and Miller (1995) called for more study to determine the ability of the preferred cleaning agent to remove Orimulsion from birds and other species and to determine the toxicity of the cleaning agent itself to various types of wildlife.

Only a small fraction of the spilled emulsified fuel is expected to re-float in an estuarine environment. The response strategies for estuaries will follow very closely those strategies discussed for the open-ocean, because the majority of the bitumen droplets will remain in suspension or sink (Table 4.3).

However, because many estuaries in the United States are also major port areas, the response time to spills should be much faster than for spills in the openocean or in coastal zones. Therefore, some of the response techniques discussed for the open-ocean and nearshore environments are appropriate for estuaries as well, and they may be more efficient because of the increased speed of response and access to shoreside support resources.

Estuaries do have zones of low flow where suspended particles may settle out, increasing the potential need for dredging or underwater vacuum recovery operations. However, the issue would be whether there is enough accumulation of “oil” to warrant bulk oil removal. Dredging and diver-assisted pumping or other types of underwater recovery operations can be very effective; however, they are also very expensive and require handling of large volumes of potentially contaminated water and sediment. Furthermore, dredging is not a commonly used spill response technique, and the required equipment may not be readily available.

Because of the fresh water and current conditions in a river, an emulsified fuel spill is expected to remain in suspension and to become more dispersed as it spreads further downstream. Therefore, tracking of the plume will require water column monitoring, either with grab water samples (limited spatial coverage, very slow) or field detectors such as fluorometers.

Even where trajectory models are available, they must be validated with field data on the location of the main body of the plume. Without preplanning that

includes purchase, training, and maintenance of the necessary equipment, the monitoring of emulsified oil in rivers will be very difficult. There are at least 75 hazardous substances currently being transported in bulk on tankers and tank barges throughout the United States that present these same problems when spilled (U.S. Code of Federal Regulations). As discovered during a 1996 survey of resources available for response to releases of bulk hazardous substances transported by water, there may be a shortage of readily available equipment and personnel trained to monitor and sample products that either disperse, dissolve, or sink (Chemical Transportation Advisory Committee, 1996-1997). However, if and when the OPA-90 regulations for hazardous substances are finalized, they may include provisions that require transporters to have the ability to readily provide monitoring and sampling resources and expertise, and this situation will improve.

There will be very little opportunity for suspended droplets to re-float in this environment; therefore, there will be little or no opportunity to recover bitumen from the water surface using skimmers (see Table 4.4). The droplets will remain in suspension until the surfactant degrades, so they will be widely distributed before they attach to other suspended matter and sink. Therefore, it is doubtful that there will be sufficient accumulations in depression and behind natural and man-made structures to substantiate a dredging or diver-directed pumping or vacuum system recovery. The most feasible response in this environment will be to deploy exclusion or deflection long-skirted booms or silt fences at water intakes and other sensitive sites downstream.

Alternatively, downstream locations where the bitumen droplets might settle out (e.g. low-flow areas, backwater sloughs) and dredging-pumping-vacuum operations might be effective could be identified. If sufficient quantities of dispersed bitumen can be diverted to these quiet areas, then the PNP Re-floater or FAF principle could be considered as a response option. Based on limited experiments, the PNP Re-floater device is about 30 to 60 percent effective in re-floating dispersed bitumen in freshwater environments (Hvidbak and Masciangioli, 2000). Although recovery is lower than for salt water, laboratory testing indicates a good recovery of dispersed re-floated bitumen in fresh water. However, aeration is essential since recovery only occurs at the surface. If the sorbent or polymer material is delivered as part of the aeration process, efficiency may be increased even further (M3 Inc., 1996).

A discharge of emulsified fuel in a freshwater, quiescent setting, such as a port facility, will offer the best opportunity for containing and recovering the spilled bitumen or oil. A facility that receives routine cargo of emulsified fuel can plan for spill events and provide the necessary equipment needed for containing and recovering it.

Furthermore, although the equipment designed for Group IV and V oils may not be as efficient as specially designed equipment, it will be more available and perhaps more rapidly deployed in this environment. Because many transfer facilities are situated in at least semi-protected areas, it is likely that the berth will be pre-boomed (or can immediately be boomed) with a deep-skirted boom or silt curtain following a spill. In this case, the majority of the bitumen droplets will remain in suspension until they sink to the bottom of the berth or are re-floated. Although the PNP Re-Floater may achieve only 30 percent success in fresh water, a fully contained spill would provide more time to work the dispersed bitumen, and a greater percentage may be obtained (see Table 4.5).

A fully contained spill at a shoreside facility would also allow greater opportunity for the use of FAF system technology. It would allow the dispersed plume to be pumped to shoreside tanks where FAF would allow separation, floatation, and recovery.

This scenario also provides the best opportunity for carrying out dredging or diver-assisted pumping operations to recover the bitumen droplets that settle on the bottom. Once on the bottom the bitumen will likely remain until recovery can take place. The shallow water depths in a port area will also be conducive to dredging operations.

When spilled on land, fresh Orimulsion will behave like a viscous liquid, with the potential for penetration into porous substrates. Response and cleanup methods would be similar to those for conventional heavy oils. As it weathers and becomes sticky, the degree of penetration will decrease, and cleanup will likely involve complete removal of the surface oil and oiled sediments. Even though the risk of groundwater contamination is low, groundwater cleanup methods would be needed for the water-soluble fraction contained in the water component.

In this type of spill, the emulsified fuel will remain in suspension when in water. Containment booming using regular containment boom and filter-fencetype material should be possible (see Table 4.6), because of the reduced current and very shallow-water conditions expected in a wetland habitat. Dikes and berms could also be constructed to isolate the spill area from other waterways and reduce migration. Depending on the amount of product spilled, the size of the area impacted, and the sensitivity of the wetland, the area could be isolated and pumped dry for manual or heavy equipment recovery of oil or bitumen from the substrate. The spill site could then be treated by burning or land farming. To ensure that only clean water was discharged downstream the effluent from any pumping operation to a dry out area could be routed through a filter box arrangement, or FAF or a PNP Refloater pumping system could be used to pump out the marsh water. In areas where the land is alternately wet and dry, emulsified fuels,

and bitumen in particular, are less likely to leach into the substrate than other heavy oils (Wood, 1996).

Because emulsified fuels are essentially predispersed, the most likely response actions will be monitoring of the dispersed plume and recovery of any refloated bitumen. Recovery efforts are likely to be even lower than for traditional spills because so little of the oil is expected to re-float. Therefore, as for all types of spills, the most effective strategy, is prevention.

Many of the proposed strategies for responding to spills of emulsified fuels are likely to have low initial effectiveness for the following reasons:

• They have not been tested under realistic conditions.

• The equipment may not be readily available at all necessary locations.

• Responders are not familiar with the equipment and strategies available for emulsified fuel spills

• There have not been spills where the proposed strategies could be tested and made more effective under field conditions.

• For example, mechanical re-floating of dispersed bitumen has been demonstrated in small intentional spill scenarios and is suggested as a practical response to a spill of emulsified fuel.

However, only actual experience will determine if it is practical to re-float any type of dispersed oil and, if required, to determine whether the methodologies being suggested are logistical and practical for likely spill scenarios. Another proposed strategy is diversion or deflection of a dispersed plume using deepskirted booms; field tests should be conducted to validate this strategy and determine the physical and environmental limitations. Tests with trawl-type nets for containing and recovering floating weathered bitumen indicate that smaller-mesh nets might make the systems more effective. Further tests are needed to determine if towing smaller-mesh nets is practical. Realistic field tests¹ and refinement of the more innovative methods for containment and recovery of emulsified fuels are required before these methods can be part of realistic response plans.