The seas had turned rough as a sudden squall whipped up the winds enough to howl through the rigging. And with those winds came a powerful smell of oil. Soon I could see the characteristic rainbow sheen from my position on the rail of this fishing trawler. It was May of 2016, and we were in the Gulf of Mexico, about 16 kilometers off the southeast coast of Louisiana, says an article published on spectrum ieee website.
Oil spills incident
There are countless oil tankers, barges, rigs, and pipelines that operate in, around, and through U.S. coastal waters. Every year, some of them leak some of their contents. In a typical year the leakage amounts to no more than a million gallons or so.
But every now and then a monster mishap spills considerably more: In 1989, the Exxon Valdez tanker ran aground on a reef and gushed some 11 million U.S. gallons (42,000 cubic meters) of oil into the pristine waters of Prince William Sound, Alaska. In 2005, Hurricane Katrina unleashed more than 8 million gallons (30,000 cubic meters) from Louisiana storage facilities.
And even those incidents pale in comparison with the Deepwater Horizon disaster in 2010, in which a drilling rig leased by BP exploded in the Gulf of Mexico, killing 11 people and ultimately releasing some 210 million gallons (almost 800,000 cubic meters) of oil.
Kennedy, a small player in a big business
In 2004, Kennedy participated in the cleanup that followed the grounding of the cargo ship Selendang Ayu—a tragic accident that cost six sailors their lives and released 336,000 gallons (1,272 cubic meters) of fuel oil into Alaskan waters.
After that incident, he became convinced he could design gear himself that could effectively recover the oil spilled on the water before it hit the beach. His design employed fishing nets and fish pumps, normally used to transfer fish from the nets into the holds of fishing vessels. (Fish pumps use vacuum instead of whirling impellers, meaning no chopped-up fish.)
When Oil and Water Do Mix
Kevin Kennedy’s open-water oil-spill cleanup system is being marketed under the name Sea Otter by his company, PPR Alaska. Here’s how it works.
- Two floating arms, arranged in the shape of a V, channel oil floating on the surface as the system is towed forward into a spill.
- Oil and water flow through a pipe to the separator chambers. A one-way valve in the pipe prevents backflow.
- Oily water flowing horizontally from the intake pipe fills one of the two chambers, which are situated side by side.
- Oil and water separate, while both are being raised above sea level by virtue of a vacuum applied by a pump through the pipe above.
- An open float valve (whose ball floats above water but below oil) allows oil to be extracted, closing before water can be sucked out.
- Releasing the vacuum allows water to flow out the bottom one-way valve until the water level in the chamber reaches sea level.
EDRC
The key term used by regulators in this industry is EDRC, which stands for Effective Daily Recovery Capacity. This is the official estimate of what a skimmer can collect when deployed on an oil spill. According to the regulations of the Bureau of Safety and Environmental Enforcement, EDRC is computed by “multiplying the manufacturer’s rated throughput capacity over a 24-hour period by 20 percent…to determine if you have sufficient recovery capacity to respond to your worst-case discharge scenario.”
Kennedy equipment certified by ASTM
Kennedy needed to get his equipment certified according to procedures established by ASTM International (an organization formerly known as American Society for Testing and Materials). So in 2017 he paid to have his equipment tested to establish its official ratings.
Those recovery ratings are determined by placing skimmers in a test tank with a 3-inch-thick (almost 8-centimeter) layer of floating oil. They are powered up for a minimum of 30 seconds, and the amount of oil they transfer is measured.
It’s an unrealistic test: Oil spills almost never result in a 3-inch layer of oil. Oil slicks floating on the ocean are usually measured in millimeters. And the thickness of an oil sheen, like that seen at the Taylor spill, is measured in micrometers.
“So many tests are really just a pumping exercise,” says Robert Watkins, a consultant with Anchorage-based ASRC Energy Services who specializes in spill response. “But that isn’t a true demonstration of response.” The value of ASTM ratings, he explains, is allowing a reproducible “apples-to-apples” comparison of oil-spill equipment. He doesn’t argue, however, that apples are the right choice in the first place.
BSEE new measures
In recent years, the Bureau of Safety and Environmental Enforcement (BSEE) and a consultancy called Genwest have worked to develop a better guide, hoping to replace Effective Daily Recovery Capacity with a different metric: Estimated Recovery System Potential (ERSP). This new measure looks at the entire system functionality and delivers far more realistic numbers.
A highly efficient system like Kennedy’s would stack up favorably according to ERSP calculations. But according to Elise DeCola, an oil-spill contingency planning expert with Alaska-based Nuka Research and Planning Group, there has been limited adoption of the ERSP calculator by the industry.
“While BSEE recommends ERSP as an industry best practice, they do not require its use,” says DeCola. “Operators that have deep inventories of low-efficiency skimmers—equipment that is still compliant with current guidelines—could suddenly be forced to invest in new skimmers.” For many, moving the goal posts would simply cost too much.
The current rules, with their lack of emphasis
The current rules, with their lack of emphasis on efficiency, accept pumping a large amount of oily water into your tanks—a mixture that must then be disposed of as hazardous waste. The better goal is to remove only the oil, and Kennedy’s equipment is about as good as you can get in this regard, with its most recent ASTM-certified oil-to-water rating being 99 percent.
What’s more, that “test tank” rating matches Kennedy’s experiences with his equipment under real-world conditions. Whether on the Taylor slick with its micrometer-thick sheen, a Lake Superior Superfund site with spilled creosote as viscous as peanut butter, or a toxic spill in California’s Long Beach Harbor, his efficiency numbers have always been very high, he claims.
Summary
- The seas had turned rough as a sudden squall whipped up the winds enough to howl through the rigging. And with those winds came a powerful smell of oil.
- Every year, some of them leak some of their contents. In a typical year the leakage amounts to no more than a million gallons or so.
- Kevin Kennedy’s open-water oil-spill cleanup system is being marketed under the name Sea Otter by his company, PPR Alaska.
- Kennedy needed to get his equipment certified according to procedures established by ASTM International.
Did you subscribe to our daily newsletter?
It’s Free! Click here to Subscribe!
Source: spectrum.ieee.org
