A six-year study at the Indian Institute of Technology in Khargpur, India also indicated that a moderate amount of fly ash (9,200 pounds per acre), along with organic sources like farm manure and crop residue, improves crop yields.
This assortment of wastes increased rice and peanut yields by 31 and 24 percent respectively when compared to using chemical fertilizers alone. Accumulation of trace elements once again remained small.
Nonetheless, agriculture’s use of ash has been limited over fears of heavy metal accumulation with repeated use, especially with ash that can contain higher amounts of toxic substances such as arsenic, wrote Li and other researchers in a paper to be published in the journal HortTechnology.
Of the coal ash produced, less than .02 percent is recycled for agriculture production, Li said, making it one of the least used byproducts of coal combustion.
“As long as we work carefully with regulators we can apply larger amounts safely,” said Li. “I think fly ash has a big potential to improve soil and increase plant growth.”
For nearly 50 years, coal combustion products have been used to fertilize peanuts. Air pollution control devices called scrubbers use a sprayed slurry of ground limestone and water to remove sulfur dioxide from gases formed in coal combustion, said Tom Schmaltz, environmental director for Headwaters Resources, a world leader in coal combustion products.
This practice leaves behind gypsum or “scrubber material,” which can be processed and transformed into drywall or added to cement and soils.
Bob Sutter, chief executive officer of the North Carolina Peanut Farmers Association, said the gypsum provides “much needed calcium and sulfur to the peanuts.”
Toxic metals are still found in the slurry, but in lower concentrations than fly ash, according to EPA studies.
“Gypsum is well established,” said Schmaltz. “We are also turning an underutilized resource into a valuable product that prevents (our) having to mine for minerals.”
For some communities, using more coal waste on farms may reduce health risks associated with coal waste ponds. Occasionally, toxic substances from waste ponds leach through soil into groundwater or breach impoundment ponds to pollute watersheds and soil.
This happened in December, when a holding pond at the Tennessee Valley Authority’s Kingston Fossil Plant spilled over its banks. The sludge, which engulfed hundreds of acres, damaged lakeside homes and polluted drinking water in Tennessee contained high levels of arsenic and elevated levels of radioactive radium, reported Duke University scientists. Three weeks later a second spill occurred in Alabama, further focusing the nation’s attention on the potential dangers of coal waste disposal.
A recent report released by the environmental law firm Earthjustice says 25 million tons of coal ash are dumped into American mines every year, threatening ground water.
As coal waste grows, large reuse projects are taking place throughout the country, some with toxic consequences. Battlefield Golf Club in Chesapeake, Virginia, is one of the largest so far, built with 1.5 million tons of fly ash. It was considered a model of successful recycling of coal combustion waste until tests of nearby groundwater wells discovered arsenic and lead levels exceeding drinking water standards, according to city water tests.
Stant said coal waste should be under federal oversight and listed as a hazardous waste.
But businesses say they already adhere to rules and laws when obtaining permits from state and local government before processing and reusing coal waste.
“N-Viro operates under a wastewater permit through the Florida Department of Environmental Protection in order to process bulk amounts of waste,” said Mayo.
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7 Comments
Add CommentIs Coal Ash in Soil a Good Idea?
Reply | Report Abuse | Link to thisIn unregulated quantities - no. The HFCS study is focused on reagents as a "the source" of contaminants, but the soil is also a source.
http://www.washingtonpost.com/wp-dyn/content/article/2009/01/26/AR2009012601831.html
Almost half of tested samples of commercial high-fructose corn syrup (HFCS) contained mercury, which was also found in nearly a third of 55 popular brand-name food and beverage products where HFCS is the first- or second-highest labeled ingredient, according to two new U.S. studies.
Listen to a real farm and soil expert. All soil amendments have good and bad effects on long term crop production. Often small amounts of toxic metals are benificial and large amounts of good neutreants toxic. Adding large amounts of material to the soil is a logistical night mare, 2000lbs. per acre is a lot, 22,000 lbs unbelievable. Even if it's free.
Reply | Report Abuse | Link to thisIf you want to eat, we will have to improve poorer soils to make up for class 1 soils covered by homes, highways, schools and shopping center parking lots.
Coal fired power plants and fuel systems are the dirtiest electric power providers on the planet. They put more radiation into the enviroment then a like sized nuclear power plant, but they are cheap to build and use off the shelf equipment. I most definately would not put nuclear waste on my fields. The dosage makes the poison.
“Although the potential human health effects are unknown…” What the heck does this mean? Of course the POTENTIAL effects are unknown. It is not science to postulate something you cannot test. The actual tests that have been and are being done show that when properly used fly ash in a very useful and beneficial amendment to the soil.
Reply | Report Abuse | Link to thisThe commentor above is right. The difference between a deadly poison and a life giving medicine is often in the dosage. Yes, massive amount of most things are harmful. The essence of intelligence is the ability to make reasonable distinctions.
Based on the information in this article, think we can answer yes to the title question “Is coal ash in soil a good idea.” We have an inexpensive way simultaneously to recycle a waste product, improve our soils and grow more food. We know how to do this in a sustainable way and we are constantly monitoring and improving our methods. Kudos all around.
Its far better to add biochar to soils, as charcoal, unlike coal has not accumulated toxins over hunreds of thousands of years.
Reply | Report Abuse | Link to thissee : www.eprida.com
biochar is a wonderful soil amendment and lasts for an extreamlly long time. the problem is you need many tons per acre to make a usefull difference. it carries little in nutreants . it does hold the nutreants in the soil structure for the plants. very valuable in high rain fall areas. and unlike humus it does not rot away in hot wet soils. very valuable in tropical farm lands, (maybe good way to trap carbon in soils )
Reply | Report Abuse | Link to thisLetter to the Editor
Reply | Report Abuse | Link to thisDear Sir/Madam
We read the article Is Coal Ash in Soil a Good Idea with great interest as we have a combined 40 plus years of experience in both agriculture and beneficial recycling of various types of by-products.
What is often confusing to the uninformed is that the terms fly ash, coal combustion products, bottom ash, flue gas desulfurization (FGD) products, FGD gypsum, coal combustion wastes and similar terms are used interchangeably as if they are all similar in chemical and physical properties. That is certainly not the case and a better term to use that incorporates all of these materials is coal combustion products.
It is certainly true that some coal combustion products can be used beneficially in agriculture to create synthetic soils, treat biosolids to reduce bacteria and pathogen levels, to serve as a source of plant nutrients, to improve soil physical properties such as water infiltration and water holding capacity and to treat soils with high concentrations of phosphorus that can lead to pollution of surface waters. In all of these instances, it is important to know the levels of heavy metals of the coal combustion product before they are land applied. The rate of application of coal combustion products is an important variable and I doubt if any reputable agronomist would recommend applications of 5 to 20 percent, as was noted in the example included in the article. Other studies cited in the article did clearly indicate that more moderate application rates of fly ash could enhance crop yields.
One specific type of coal combustion product is FGD gypsum. This material is created when a calcium based sorbent is reacted with sulfur dioxide gases that are created when high sulfur coal is burned. The calcium and sulfur react to form calcium sulfite that is then oxidized to form a very pure form of calcium sulfate (CaSO4
One specific type of coal combustion product is FGD gypsum. This material is created when a calcium based sorbent is reacted with sulfur dioxide gases that are created when high sulfur coal is burned. The calcium and sulfur react to form calcium sulfite that is then oxidized to form a very pure form of calcium sulfate (CaSO4•2H2O) or gypsum. This gypsum has been compared with mined gypsum and is generally much purer and contains equal to or less quantities of heavy metals. Gypsum has a long history of use in agriculture that goes back to the Roman times and, indeed, even Benjamin Franklin extolled the virtues of gypsum as an agricultural amendment. FGD gypsum, when applied to soil has the potential to provide many benefits including (1) the enhancement of no-tillage crop production, which in turn can help reduce greenhouse gases in the atmosphere as no-tillage removes carbon dioxide and put the carbon back into the soil, (2) improvement of efficacy of N fertilizers for crops, (3) remediation of sodic soils, (4) improvement of water and air entry into soils, (5) reducing the negative effects of subsurface soil acidity on crops, (6) mixing with other materials during composting to reduce ammonia losses and to create synthetic soils, and (7) reducing phosphorus concentrations in surface water runoff. Work in China has unequivocally shown that FGD gypsum can remediate sodic soils so that these lands can be brought back into productive agricultural use and studies in the United States have shown similar benefits.
Reply | Report Abuse | Link to thisFGD gypsum can only be used, however, if the concentrations of heavy metals in the material do not lead to accumulation of the metals in soil. In all of our studies, we have not observed such a phenomenon. The one concern that remains in this regard is mercury and studies are ongoing to determine whether the levels in FGD gypsum, while still very low, pose any environmental and ecological threat. At the same time, studies are being conducted to remove the mercury from the FGD gypsum before it is ever used for land application purposes.
We have seen the enthusiasm by farmer producers in using FGD gypsum to enhance the overall quality of their soils and to improve the yield of crops. When used appropriately, FGD gypsum poses no threat to the environment and the products grown on the land treated with the FGD gypsum at rates we recommend are not significantly enhanced in heavy metal content. The benefits of recycling have been duly noted by many and we look forward to continued use of FGD gypsum to provide economic benefit to our agricultural enterprises as well as environmental benefit in terms of reduced land disturbance to obtain gypsum from mining activities and the remediation of degraded lands.