In an effort to prevent another coal-ash disaster, TVA announced last week it will convert its Kingston plant and five others from wet storage to dry storage at a cost of between $1.5 and $2 billion, which is in addition to the $1 billion or so in cleanup costs from last December's spill.
TVA currently has six wet ash and five dry ash plants under its care. Converting the Kingston plant will cost around $70 million, according to John Kammeyer, vice president of coal combustion productions at TVA and head of ash operations.
Still to be determined is whether the dry ash will be stored at Kingston permanently or hauled off to a landfill of some kind, but an environmental review is now underway and could take up to a year to complete. According to Kammeyer, the ash will probably not be stored on site permanently but may have to reside there temporarily until a proper site is found.
So what's the difference between wet and dry ash storage? It's actually pretty straightforward, but for the answer I went to the EPA's headquarters in Washington.
1. What exactly is dry handling, and how does it differ from wet handling? Dry handling refers to the management of coal combustion residuals (CCRs) in a dry or semi-dry state, while wet handling refers to managing CCRs by slurrying the material and pumping it into a surface impoundment.
2. What environmental risks are posed by dry handling, and are they significantly fewer than wet handling? Risks vary as a result of quantity of material managed, geologic conditions for a particular landfill or surface impoundment, and many other factors. Generally, because the CCRs in a surface impoundment come into contact with water, constituents leach from the CCRs at higher levels than if they are managed in a landfill.
3. What costs are associated with dry handling, and is there a danger living near a storage site (silo)? Dry handling is more expensive than wet handling as a general rule. Unit costs vary due to quantities being managed, physical location of disposal sites, transportation costs, and many other factors. Regarding the risks posed by storage of CCRs prior to transporting them to a disposal site, if proper techniques such as wetting the materials so they do not disperse in the air are employed, there is little risk posed. If the materials are allowed to disperse into the air and someone lives close enough to be impacted by wind blown particulate matter, risks could occur.
4. If dry storage is preferable, why don't all sites use it? It is not clear that one method of handling materials is "preferable." Safe management of CCRs is possible for both landfills and surface impoundments, provided proper safeguards are provided (e.g., lined units). However, wet handling is generally less expensive that dry handling.
5. After the coal ash spill last December, is there work to make this so? EPA is working on a proposed regulation that would address the risks posed by the management of CCRs. We will be taking comment on various approaches to managing CCRs, and will take comment on whether a phase-out of wet handling is warranted.
TVA currently has six wet ash and five dry ash plants under its care. Converting the Kingston plant will cost around $70 million, according to John Kammeyer, vice president of coal combustion productions at TVA and head of ash operations.
Still to be determined is whether the dry ash will be stored at Kingston permanently or hauled off to a landfill of some kind, but an environmental review is now underway and could take up to a year to complete. According to Kammeyer, the ash will probably not be stored on site permanently but may have to reside there temporarily until a proper site is found.
So what's the difference between wet and dry ash storage? It's actually pretty straightforward, but for the answer I went to the EPA's headquarters in Washington.
1. What exactly is dry handling, and how does it differ from wet handling? Dry handling refers to the management of coal combustion residuals (CCRs) in a dry or semi-dry state, while wet handling refers to managing CCRs by slurrying the material and pumping it into a surface impoundment.
2. What environmental risks are posed by dry handling, and are they significantly fewer than wet handling? Risks vary as a result of quantity of material managed, geologic conditions for a particular landfill or surface impoundment, and many other factors. Generally, because the CCRs in a surface impoundment come into contact with water, constituents leach from the CCRs at higher levels than if they are managed in a landfill.
3. What costs are associated with dry handling, and is there a danger living near a storage site (silo)? Dry handling is more expensive than wet handling as a general rule. Unit costs vary due to quantities being managed, physical location of disposal sites, transportation costs, and many other factors. Regarding the risks posed by storage of CCRs prior to transporting them to a disposal site, if proper techniques such as wetting the materials so they do not disperse in the air are employed, there is little risk posed. If the materials are allowed to disperse into the air and someone lives close enough to be impacted by wind blown particulate matter, risks could occur.
4. If dry storage is preferable, why don't all sites use it? It is not clear that one method of handling materials is "preferable." Safe management of CCRs is possible for both landfills and surface impoundments, provided proper safeguards are provided (e.g., lined units). However, wet handling is generally less expensive that dry handling.
5. After the coal ash spill last December, is there work to make this so? EPA is working on a proposed regulation that would address the risks posed by the management of CCRs. We will be taking comment on various approaches to managing CCRs, and will take comment on whether a phase-out of wet handling is warranted.
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