July 25, 2005
Three waste technologies may be alternatives for swine industry
Three additional alternative methods of treating the waste from swine farms have made what might be called the first cut toward being declared “environmentally superior” to the method now used by most North Carolina hog farms to treat waste.
Dr. Mike Williams, director of the Animal and Poultry Waste Management Center at North Carolina State University, added three technologies to the two that were determined last year to have met what Williams called “environmental performance criteria” necessary to be considered environmentally superior. Williams made his selections in an annual report delivered to the North Carolina Attorney General’s office Monday, July 25.
Williams directs an effort to identify swine waste management technologies that are considered environmentally superior to the lagoon and spray field system now used on almost all North Carolina hog farms.
None of the five technologies singled out thus far has been declared environmentally superior. In order for that to happen, they must be judged economically and operationally feasible. Williams said that won’t happen until later this year, when he releases a final report on the five-year, $17.3 million effort.
The effort is funded by pork producers Smithfield Foods and Premium Standard Farms under agreements the two companies reached with the North Carolina Attorney General in 2000. Since then, experts from NC State University and elsewhere have been evaluating alternative swine waste management technologies.
While the Smithfield agreement spells out environmental criteria the technologies must meet, it also stipulates the technologies must be economically feasible. Williams said the economic feasibility analysis is not complete, and until the economic work is finished, his determinations should be considered conditional.
The three technologies that Williams determined meet environmental standards all treat only the solid portion of the waste stream from a hog farm. So if any of the three is to find its way to North Carolina farms, it would have to be combined with a technology that treats the liquid part of the waste stream.
Two of the technologies that meet environmental standards treat solid waste by burning it, while the third is a composting system.
One of the two technologies that burn waste does so in a chamber called a gasifier. Gasification involves burning a substance in a low-oxygen environment, which converts complex organic compounds in the substance to gases. It is possible to collect gases such as methane, carbon monoxide and hydrogen and make ethanol.
The second burning technology goes by the acronym BEST, for Biomass Energy Sustainable Technology, and includes two methods of separating the solid and liquid portions of the waste stream. Solids are then burned in a fluidized bed combustion system. In this system, the temperature is above 1,300 degrees.
Both combustion systems produce ash, which contains nutrients and has value as a fertilizer.
The composting system was developed by Super Soil Systems USA. Waste is mixed with bulking materials such as cotton gin residue and wood chips, while a machine called a Compost-A-Matic is then used to mix the material daily.
Another Super Soil Systems technology that separates solids from the waste stream, then treats the remaining liquid waste in a series of large metal tanks was given conditional approval last year. Thus far, this technology is the only one that treats the liquid waste stream to receive conditional approval.
In order to meet environmental standards, technologies must:
* eliminate the movement of animal waste to surface waters and groundwater through direct discharge, seepage or runoff;
* substantially eliminated atmospheric emissions of ammonia;
* substantially eliminate the emission of odor that is detectable beyond the boundaries of the farm;
* substantially eliminate the release of disease-transmitting vectors and airborne pathogens; and
* substantially eliminate nutrient and heavy metal contamination of soil and groundwater.
As did last year’s report, this year’s includes assessments of eight technologies. Williams said that while five of the 16 technologies now meet the environmental performance criteria, several others could with relatively minor changes. He added that it may also be possible to combine elements, or processes, from different technologies to produce systems that will meet the environmentally superior standard.
Smithfield Foods is providing $15 million to evaluate technologies, while the attorney general allocated $2.3 million from the Premium Standard Farms agreement, for a total of $17.3 million.
In 2002 the attorney general entered a third agreement with Frontline Farmers, an organization made up swine farmers. While Frontline Farmers is not providing funding, the organization’s membership agreed to work with the attorney general and NC State University to develop and implement environmentally superior technologies.
The technologies that have been evaluated were selected by Williams working with panels made up of representatives from government, the swine industry and environmental groups as well as economists and waste management experts. In many cases, technologies have been evaluated on hog farms at full scale.
- Dave Caldwell
Note: The report delivered to the Attorney General’s office is more that 1,000 pages. It will be available later this week on line at http://www.cals.ncsu.edu/waste_mgt/smithfield_projects/phase2report05/phase2report.htm.
Posted by deeshore at July 25, 2005 01:59 PM