Washcloths for the World's Oceans
While we're not paying attention, oil gets spilled here and there around the globe. Within the past month, I've talked with one friend who had visited the site of the Shetland Islands spill and another who had been at Palmer Station in Antarctica during the big spill there. Most of the mislaid petroleum comes in less headline-grabbing amounts, though; just last week, a friend who lives on the East Coast complained about beach closures caused by 500 gallons of diesel fuel floating where it didn't belong.
Despite headlines and complaints, the technology for cleaning up spilled oil hasn't made much progress. Alaska scientists are studying such matters as hydrocarbon-eating bacteria and the fate of petroleum in the food chain, but work on devising better mops to pick up spilled oil now is under way elsewhere---appropriately enough, in Texas.
Research led by Harry W. Parker of Texas Tech University improves on present technology. According to Science News, Parker's team has sopped up oil with natural fibers unsuitable for making cloth (short, frizzy cotton fibers and thick, scratchy wool fibers.) The low-grade fibers are no better at absorbing petroleum than the synthetic fibers now used as sorbents, but the natural fibers are biodegradable. On the lab benches of Texas Tech, bacteria effectively degraded the cotton and wool, even when they were soaked with a full load of diesel or crude oil. The oil itself is released when the fibers are eaten away. It can undergo further processing by oil-digesting microbes, or it can be recovered for use.
The process sounds good, but, unfortunately, biodegradation is more expensive than burying oily sorbents in a landfill. However, the Environmental Protection Agency is attempting to reclassify oil-soaked material as hazardous waste, which would make burial much more costly and biodegradation much more competitive.
The Texas Tech group's largest biodigestion container holds only about two liters of water and waste. By this October, they hope to run pilot-scale tests with 50- to 250- gallon containers, which are large enough to determine realistic feasibility and costs for using biodegradable sorbents. So, for now, this promising technology awaits answers to questions of scale and cost.
A different team of Texans is probing more unusual technology. Adam Heller, of the University of Texas at Austin, leads a group working on what might be the world's smallest catalytic reactors. They've coated tiny glass bubbles with titanium dioxide, a white pigment that accelerates the natural chain of chemical reactions decomposing hydrocarbons, In the presence of oxygen and sunlight, oil eventually breaks down into carbon dioxide and water. Helped by the surface area of the glass spheres and the properties of the titanium dioxide, the process proceeds far more rapidly than normal. Heller reports that under optimum conditions, the beads can decompose their weight in oil every hour.
He also notes that the beads are nontoxic, since glass has the same composition as sand and titanium dioxide and is acceptable for use in cosmetics and vanilla pudding mixes. But being nontoxic is not the same as being harmless. The oil-coated beads could be eaten by animals, which would stop the sunlight-mediated breakdown of the oil and could poison the animals. Work done at the University of Alaska Fairbanks' Institute of Marine Science showed that plastic foam pellets, the beadlike raw material from which coffee cups and foamboard are made, look just like edible fish eggs to a variety of sea creatures. They might similarly hunt for the glass beads, and starve to death with full bellies. The beads also are expensive to make.
Thus neither team has yet devised the magic bullet to shoot down spilled oil, so to speak. I hope they succeed. While we work to prevent future Alaska spills, it would be nice to have on hand all the effective clean-up technology from Texas, or anywhere else, that we can get.
