The Role of Coal in Providing Security to the US Food Supply

When discussing U.S. energy/national security, one issue that has been raised over the last few years is the role of coal in providing security to the U.S. food supply. There has been concern among some individuals in the U.S. rendering industry and certain government agencies about ensuring a safe food supply from both natural and humanmade threats (i.e., terrorism, disease outbreaks). The diseases of most concern include hoof-and-mouth disease, bovine spongiform encephalopathy (BSE, or "mad cow" disease), and chronic wasting disease (CWD) [31-36]. These concerns stem from the incident of BSE and hoof-and-mouth disease widely reported in Europe, the outbreaks of CWD in the United States (such as the 2004 incident in Wisconsin) [34,35], the first reports of BSE in North America which occurred in Canada, the detection of BSE in the United States in December 2003 [37], and the 2004 threat of acts of terrorism against the United States. Penn State has been working with various rendering companies, trade organizations, and government agencies for several years to evaluate the potential of using animal fats, proteins, and carcasses as boiler fuels [38-40].

It was noted in 2001 that BSE, which is a major health concern in Europe, had a very low risk potential for occurring in the United States, as determined by a landmark study by Harvard University [41]. The study did identify a potential pathway for the spread of BSE in the animal chain through deadstock (i.e., dead and downer animals) on farms and ranches. This issue was being addressed by specific handling practices in the rendering industry and through regulatory options [31-33,36]. Interestingly, it was a paralyzed cow, a downer, that was detected in the U.S. food chain as having BSE that set off the scare that resulted in many changes in the rendering/packing industry, negatively affected the export market (resulting in layoffs of meat packing workers), and resulted in a downturn in the beef industry economy [36,42,43]. New regulations anticipated in Spring 2004 are expected to increase the amount of specified risk material from about 1.5 lb/beef carcass (brain and spinal cord) to 100 lb/carcass, forcing the industry to explore various disposal options [36].

One issue with regard to a major disease outbreak is how to dispose of a large number of carcasses in a short period of time, which will be necessary to limit proliferation of the disease. A recent example, although on a much smaller scale, was the need to identify disposal options for deer in Wisconsin infected with CWD in 2002 [34,35]. Approximately 10,000 to 25,000 deer in a 360-square-mile area were targeted to be killed to stop the spread of CWD [34]; however, identifying options for disposing of the carcasses was a major problem. Options identified included landfilling, rendering, and incineration/digestion [34]. Rendering was an option in this case because there were facilities that had the capability to process this quantity of material (each deer weighs 120 to 140 lb). There was a concern, though, about the wastewater that would be produced during the rendering. Preliminary tests were performed in which a few deer carcasses were disposed of at a foundry, and apparently the tests were successful (although the number of carcasses disposed of was small and no stack testing was performed to measure emissions). The decision was made to incinerate the carcasses [44]. This was an example where the number of carcasses (and total weight) could be handled with existing methods and infrastructure; however, an important concern is how to dispose of a large herd of cattle in an emergency situation and what options would be available. With proper planning and foresight, both utility and industrial boilers can be used to handle such an emergency. Doing so will involve a partnership of the packing/rendering industry, the federal government, and boiler owner/operators. The federal government's role would include emergency oversight and funding for modifying boilers (prior to the emergency) and handling/disposing of carcasses during the emergency.

The types of boilers that can be used in an emergency include boilers currently designed for liquid fuels as well as existing fluidized-bed boilers. It is understood that, should there be an outbreak of a highly contagious disease such as hoof-and-mouth disease, the herd is to be quarantined with severe restrictions on movement into and out of the infected area. The rendering industry can move a mobile system into this area via rail, and rendered fats can be utilized in the boiler, thus supplying steam to the rendering process as well as providing rendered fats, which have a heating value nearly as high as number 6 fuel oil (i.e., ~ 18,000 Btu/lb), to other boilers in the immediate area. However, the number of carcasses that can be processed per day in this manner is limited, and other options should be explored, including cofiring the carcasses with coal in a fluidized-bed system or firing the carcasses in a boiler designed specifically for this feedstock. In the case of a hoof-and-mouth outbreak, the boiler would need to be nearby. For other cases, such as outbreaks of CWD, avian influenza (AI), or the identification of BSE cases, it will be easier to transport the animals or birds to the boilers and the number of candidate boilers would be larger.

In one example of planning for a national emergency, targeted fluidized-bed boilers throughout the country could be modified with emergency handling systems (although one hopes that they will never have to be used) that will take an entire carcass, grind it (as is currently done in the rendering industry), and feed the "chunked" cow directly into the fluidized-bed boiler. The chunked cow, with a heating value of about 4000 Btu/lb [36], can easily be cofired with coal and can even be a stand-alone fuel in a boiler designed for this feedstock. The first step in identifying candidate boilers will be to overlay maps of locations of fluidized-bed and other appropriate utility and industrial boilers with rendering and packing facilities as well as major herd concentrations (which tend to correspond to meat packing facilities). As an example, Figure 5-11 in Chapter 5 provides a map of the United States showing the locations of coal-fired, fluidized-bed boilers that could be utilized.

The rendering industry is currently interested in installing industrial-sized, coal-fired, fluidized-bed boilers to dispose of deadstock, and preliminary inquiries have been made of boiler vendors. The rendering industry is interested in this because it has the potential to solve the problem of disposal of deadstock, which can be 100,000 to 200,000 carcasses per year, while producing steam to meet their processing needs [45].

Similarly, an outbreak of AI in Virginia in 2002 was handled by disposing of approximately 16,000 tons of dead birds in landfills at a cost of $2.5 million [46]; however, Brglez [46] has shown that the birds could have been rendered into meal and utilized as a fuel at a nearby cement plant at a savings of $1 million to the industry. The concept of using animal meal to displace 10 to 15% of the coal (on a heat input basis) in cement kilns is currently being practiced in France and Italy [46]. Utilization of these types of materials as a cofire fuel with coal, instead of landfilling them, should become standard practice. This has three benefits: reduced disposal costs for the food industry, reduced fuel costs to the boiler operator, and enhanced national security to the U.S. food supply.

0 0

Post a comment