The town of Kolontar in western Hungary is about halfway between Budapest and the Austrian border. Like many other former Iron Curtain countries, Hungary has its share of old heavy-industry installations, and an alumina processing plant stands next to Kolontar. The facility no doubt provides some welcome employment, but the preferred method of making alumina is a nasty business. You start with bauxite, which is a mixture of pure alumina (aluminum oxide, from which the metal is made) and other minerals. These other minerals do not dissolve when you treat the ground-up bauxite with sodium hydroxide, otherwise known as lye. The alumina stays in solution as it converts to aluminum hydroxide, you filter out the undissolved material, and then heat up the hydroxide to turn it back into pure alumina, now minus the other minerals.
So far, so good. But what do you do with the leftovers, especially when we’re talking about tons of material a day? The byproduct of this process is called “red mud,” and there’s not much use for it. It still has the pH (a measure of acidity or basicity) of lye, and if there were any heavy metals such as arsenic or mercury in the original bauxite, they are still in the red mud. The Hungarian Aluminum Production and Trade Company, which owns the plant, chose to build large open retaining reservoirs and simply ran the mud out to the reservoirs. As long as the reservoirs held together, this at least localized the problem. But last Monday, Oct. 4, one of the retaining walls (perhaps weakened by heavy summer rains) collapsed. According to an MSNBC report, the resulting red tide flooded most of Kolontar and parts of other nearby towns, killed at least seven people, and sent 150 or so to hospitals for treatment of alkali burns and other injuries.
The investigation into the cause of the collapse is just beginning, but the issue I’d like to address is the practice of what you might call deferred environmental protection. Thousands of various industrial processes make byproducts which, like red mud, take up a lot of space but have no economic value. In fact, to the extent that getting rid of them costs money, they have negative economic value. To treat red mud so that it could be used as fill at construction sites or even in garden soil would cost a lot, first to neutralize the alkali content with acid and then to filter or extract the hazardous heavy metals. If the firm that runs the Kolontar facility spent all this money to make red mud at least disposable without danger, their alumina would cost more than the average commodity price, and the firm would likely go out of business—at least out of the alumina business.
I’m no chemical engineer, and I don’t know what the standard practices are for alumina production. But I suspect that in today’s global economy, the other alumina producers are doing pretty much the same thing as the Kolontar factory did. The only reason we haven’t heard about them is that their reservoirs haven’t sprung leaks—yet.
To what extent should we tolerate the warehousing of hazardous materials in localities where they do no immediate harm, as long as proper precautions are taken? At any given time around the world, there are thousands of tons of highly poisonous materials in chemical plants, factories, and city warehouses, and an accidental release of just one of these materials could kill thousands, as it did in the 1984 Bhopal, India toxic-gas disaster. But because our modern industrial society demands good things that require dealing with these nasty chemicals, we put up with the danger of having them around. And it is largely the responsibility of engineers to see that hazardous materials stay under control, even if they have no useful economic purpose.
Sometimes indefinite storage of hazardous waste just has to be built in to a business plan. Because there is not yet a national storage facility for radioactive waste, most U. S. nuclear power plants have to store their spent fuel on site. The cost of doing this projected into the indefinite future is factored into the cost of doing business. Fortunately, the volume of nuclear waste is much smaller than the waste products of a coal-fired power plant, for example, so the storage problem has proved to be manageable so far.
But alumina production is a different affair. In 2009 the stuff was selling for only about $300 a ton, so dealing with a highly competitive world commodity market means that alumina producers simply can’t afford a lot of fancy pollution-remediation facilities that their competitors aren’t using. In countries such as the U. S. where environmental laws are fairly strict, you don’t see a lot of alumina factories, partly because compliance with the laws here would quite possibly price their product out of the market altogether. If you take a strictly nationalistic viewpoint, you could say that if a country such as Hungary chooses to let its industries produce cheap, profitable commodities at the expense of polluting large tracts of land and putting whole villages at risk, then it’s their right. But I doubt that a well-functioning democracy would knowingly allow the kind of dangerous behavior that resulted in last week’s red-mud disaster.
At the very least, inspections and repairs to the reservoirs should have been better. Future generations would still have to deal with the question of how to dispose of the red mud, but at least the problem would have been under control. Once the investigation is complete, we can make a better-informed judgment about what happened in Kolontar and how similar tragedies can be avoided in the future. But the answers may not be easy to come by.
Sources: The MSNBC article I referred to is at http://www.msnbc.msn.com/id/39570826/ns/world_news-europe/#slice-2. I also consulted the Wikipedia article on alumina for details of the refining process.