This is rather obscure to most people, because it is industry specific, but it points out what happens when good-hearted and well-intentioned environmental activists don’t think things through.
The Fly Ash Threat
Designation as hazardous waste could turn concrete’s environmental image on its head.
Source: CONCRETE PRODUCER MAGAZINE
Publication date: January 1, 2010
By William D. Palmer Jr.
View PCA’s response to the fly ash designation issue, “Fly Ash in Concrete-Benefits of Use and Impacts of its Designation as a Hazardous Waste.”
The concrete industry as we k know it may be changing in response to an event that happened on Dec. 22, 2008.
At a Tennessee Valley Authority (TVA) electric generating plant in Kingston, Tenn., one dike of a containment pond ruptured, spilling more than 5.4 million cubic yards of coal ash slurry. The Emory River was inundated and covered with more than 300 acres of wet fly ash. Cleanup is expected to cost more than $1 billion.
No one disputes this spill was a major engineering failure that led to a local environmental disaster. Four homes were destroyed and more than 20 were damaged. No one was injured and, despite dire predictions from environmental activists, water quality in the area did not significantly deteriorate. “All EPA, TDEC (Tennessee Department of Environment and Conservation), and TVA water treatment facility sampling results … continue to meet water quality standards for drinking water,” the TVA stated.
What is in dispute is what to do next. Spurred by cries of environmental activists to prevent such accidents, the long-term consequences of this accident, based more on politics than science, could change the way fly ash is used or disposed of in the U.S. for the foreseeable future. If fly ash is declared a hazardous waste, it is impossible to overstate the damage the concrete industry would suffer.
The EPA considers fly ash a nonhazardous waste material under Subtitle D of the Resource Conservation and Recovery Act (RCRA). This means that individual states have jurisdiction over the material’s storage and disposal. Environmental groups want this ruling changed so that fly ash is classified a Subtitle C hazardous wastes which would be regulated by the federal government.
OK, so what’s wrong with designating fly ash a Subtitle C hazardous waste? Roughly half of the electricity generated in the United States comes from coal-burning plants. This produces about 130 million tons of coal combustion products (CCP). About 55%, or 72 million tons, is fly ash, and about half the fly ash generated is currently used for beneficial purposes, mostly in concrete. That’s roughly 36 million tons of what is essentially a waste product being recycled into something useful.
Flyash differs slightly by source, but, generally speaking, flyash weighs about 70 lb/ft³. Thirty-six million tons of flyash is slightly more than a billion cubic feet of material, of waste product. It’d be kind of nice to have something to do with that material other than put it in a landfill, right?
I’d think so! Flyash is a pozzolan, which means that it is not cementitous itself, but becomes cementitous when mixed with Portland cement; the excess calcium hydroxide liberated in the hydration (setting) process enables the flyash to become cementitous.
Flyash varies in grade and pozzolanic activity, and some simply cannot be used. There are some disadvantages to using flyash as a partial cement replacement in concrete, but there are plenty of advantages, too. Further, by replacing some of the cement used in concrete, flyash lowers demand for the production of Portland cement.
The Portland Cement Association says that roughly one ton of CO2 is released in the manufacture of one ton of cement; for every ton of cement replaced by flyash, that would mean a ton less CO2 emitted.
The Electric Power Research Institute estimates that beneficial use of CCPs annually saves 159 trillion Btu, 32 billion gallons of water, 11 million tons of CO2 released to the atmosphere, and 51 million cubic yards of landfill space.
But what happens if the Environmental Protection Agency reclassifies flyash as a Subtitle C hazardous waste? The American Concrete Institute told the EPA that such a hazardous designation would probably result in flyash being removed from most specifications and standards, including the ACI 318 Building Code Requirements for Reinforced Concrete. Once flyash is designated as hazardous, the liability involved in using flyash in concrete skyrockets.
The linked article mentioned that part, but there’s a lot more involved that was left out. If flyash is designated as hazardous, then the collection, handling and storage of flyash would all have to change; you cannot handle a hazardous waste in the same manner as a mostly inert mass. This would lead to significant cost increases for coal burning power plants, costs which would be passed on to the consumer in the price of electricity. Add to that having an additional 36 million tons to do whatever with, a further increase in costs, along with the loss of the sale of the material in the first place. All of that would fall on the shoulders of the customers of the utilities involved.
Not every concrete producer uses flyash, but a whole lot do; I use flyash. I store flyash in a single-walled silo, from which it is gravity-fed into the cement scale as needed. Flyash is delivered to the plant in single-walled trailers, and blown up into the silo with a forced air blower. If flyash is designated a hazardous material, it will become a lot more expensive to transport and handle; a concrete producer cannot risk a leak in a silo, or a leak in the hoses, pipes and connections through which the flyash is blown up into the silo. Simple and normal repairs and maintenance, such as changing an aeration pad, will become much more difficult as none of the material can spill, and all of the personnel involved will require special training, tools and personal protective equipment. The hauling company which delivered the flyash would need special trailers, and an accident which resulted in the release of some of the flyash would become a hazmat problem. Even if ACI was wrong, and flyash wasn’t removed from specifications, the material would become much more expensive to handle from the standpoint of a ready-mixed concrete producer; there would be no economic advantage in using it, and the liability in the event of a significant spill could be enormous, possibly enough to bankrupt a smaller producer. I’d advise any ready-mix company to simply eliminate flyash from their concrete if it is declared a hazardous waste.
It doesn’t matter how well-intended this proposal is: the result would be millions of tons of flyash wouldn’t get recycled, and millions more tons of Portland cement would have to be produced or imported. Costs would increase for contractors, concrete producers and electric utilities, and there would be more, not less, pollution as a result.