Tuesday, October 13, 2009

Scrubbed emissions from coal plants ending up in the water

This is a case of solving one problem and creating yet another. A NY Times article reports on how scrubbing emissions at coal fired power plants results in toxic chemicals going into the water system. Given that water resources are tight it is insane to make the water unsafe by adding pollution but at the same time it's insane to simply let this pollution go into the air. On the one hand there's a way to reduce the toxicity of burning coal in power plants, the question is what to do with the toxic chemicals once they're prevented from going into the atmosphere. Or as Sen. Boxer said:

“We know that coal waste is so dangerous that we don’t want it in the air, and that’s why we’ve told power plants they have to install scrubbers,” said Senator Barbara Boxer, the California Democrat who is chairwoman of the Senate Committee on Environment and Public Works. “So why are they dumping the same waste into people’s water?”

CCP.jpgWhile she has a very good point her question is rather disingenuous. Obviously if the toxic chemicals are removed from gaseous emissions the toxic chemicals still exist and have to be put somewhere, the question is "where"? The NY Times article goes on to discuss that "no federal regulations specifically govern the disposal of power plant discharges into waterways or landfills" and that some regulators attempt to use the Clean Water Act to regulate such emissions. The Clean Water Act is insufficient for this purpose and in any case the NY Times article reports even for plants who are regulated under this act the vast majority are in violation and are not fined or otherwise sanctioned by the agencies who would be regulating them.

The NY Times article states that often states fight against stricter regulations. An example is this listing by the DOE of state regulations in Kentucky ("Coal, Kentucky's Ace in the Hole"):

Current Regulations Governing Coal Combustion By-Products - Kentucky: Under Kentucky regulations, CCBs (including fly ash, bottom ash, and scrubber sludge produced by coal-fired electrical generating units) are exempt from regulation as hazardous wastes but are classified as special waste. Excluded from this regulation is boiler slag and residues of refuse-derived fuels such as municipal waste, tires, and solvents. Under Kentucky law, CCBs (as defined above) may be reused under permit by rule regulation 1) as an ingredient in manufacturing a product; 2) as an ingredient in cement, concrete, paint, and plastics; 3) as an anti-skid material; 4) as highway base course; 5) as structural fill; 6) as blasting grit; 7) as roofing granules; and 8) for disposal in an active mining operation if the mine owner/operator has a mining permit authorizing disposal of special waste. Specific conditions for reuse of CCBs include: 1) the CCB reuse may not create a nuisance; 2) erosion and sediment controls must be undertaken; 3) the CCB reuse must be at least 100 ft from a stream and 300 ft from potable wells, wetlands, or flood plains; 4) the ash must be "non-hazardous;" and 5) the generator must submit an annual report. Mine applications must be specifically authorized under the terms of a permit issued by the Department for Surface Mining, Reclamation and Enforcement.

Another example of the problem is this report by Califormia's Air Resources Board on Disposal of Scrubber Wastes (PDF). It's a very long report but begins with a discussion of the total scrubber waste which would come from eight utility and four utility sites being studied. Among the wastes is 9700 tons of "purge water" which would be produced and require disposal. The purge water was said to contain 70 percent solids so maybe the word "sludge" is better than "purge water"? In any case their casual use of this phrase, "purge water", indicates that for them this is a routine matter of course issue. Hence Sen. Boxer's incredulity quoted above seems misplaced or misinformed as someone in her position ought to already know about this issue.

Perhaps proving that "what goes around comes around", EPA Says Scrubbers Necessary for Health Protection Under Coal Conversion Plan is a historical press release from 1977 going over how "President Carter's Energy Plan calls for maximum conversion of this nation's electric power plants from oil to coal combustion". An issue facing the U.S. during the 1970's was repeated oil embargo's and additionally President Carter famously addressed the nation about the future danger that we now know as Peak Oil. Pres. Carter was prescient enough to see that oil supply problems would only get worse due to the majority of oil reserves being located in unfriendly countries. So he led the country to switch from oil fired electricity generation to coal fired electricity generation.

One of the already known phrases for this is "Coal Combustion Products" which are the byproducts generated from burning coal in coal-fired power plants. These byproducts include fly ash, bottom ash, boiler slag, and flue gas desulfurization gypsum. Astonishingly these CCP's are routinely used in a variety of building materials.

CCP Production In Tons
Concrete/Concrete Products/Grout 14,515,690
Blended Cement/ Raw Feed for Clinker 4,989,988
Flowable Fill 127,406
Structural Fills/Embankments 10,598,118
Road Base/Sub-base 1,179,509
Soil Modification/Stabilization 1,371,228
Mineral Filler in Asphalt 102,723
Snow and Ice Control 781,346
Blasting Grit/Roofing Granules 1,449,561
Mining Applications 6,701,910
Gypsum Panel Products 8,254,849
Waste Stabilization/Solidification 2,800,031
Agriculture 180,100
Aggregate 1,013,373
Miscellaneous/Other 1,973,173

The EPA claims some benefits of using these CCP's include

  • reduction of greenhouse gasses that would otherwise be created during concrete production
  • concrete with fly ash is stronger than other concrete
  • doesn't need to be put in landfills
  • reduces the amount of "virgin materials" which have to be mined

The EPA also lists some of the risks.

  • fly ash contains toxic materials such as "heavy metals" but "for all practical purposes" there is no leaching of those toxic materials
  • workers handling dry coal ash are of course exposed to these toxic materials
  • there is also "unencapsulated" uses of these materials (making concrete is an "encapsulated use") in which there is leaching of elements such as mercury and metals into ground water, contamination of vegetation and the impact on other elements on the food chain, and airborne dust.

The Recycled Materials Resource Center contains an extensive set of guidelines for reusing various "by-product materials" for use in "secondary applications". As they point out "virgin materials" are becoming scarce and the volume of "by-product materials" is increasing. Hence it makes sense to use those "by-product materials" in some other way, with highway construction being seen as a primary potential use. The guide is "intended to provide the reader with general guidance on engineering evaluation requirements, environmental issues, and economic considerations for determining the suitability of using recovered materials in highway applications".


No comments:

Post a Comment