Composting best carcass disposal method
April 22, 2009 by North Dakota State University Extension
April 20, 2009, Fargo, ND – This year’s spring flooding and blizzards have caused many livestock deaths.
Methods of disposing of dead animals include burning, burying and composting, but burning and burying have drawbacks, according to Chris Augustin, area nutrient management specialist at North Dakota State University’s Carrington Research Extension Center.
One of the problems is finding a suitable burial site during flood times, he says. When burying dead animals, you need to avoid areas with sandy soils and shallow water tables.
The site should be nearly level to moderately sloping and at least 200 feet away from surface water, says Karl Rockeman, an environmental engineer with the North Dakota Department of Health. The bottom of the disposal pit should be at least four feet above the water table and underlain with loamy, silty, clay soils. Carcasses should be covered by four feet of soil.
Burying dead livestock within the water table or in sandy or gravelly soil is unacceptable, Rockeman says. Also, do not locate the burial pit near residences, wells, shallow aquifers or areas that may be flooded, and avoid pipelines, utility easements and historically significant sites.
Burning can be difficult because the law requires you to use organic fuels, such as wood, which can make creating enough heat to effectively combust a carcass difficult. Also, the state department of health must grant an open-burning variance prior to the burn.
Composting may be the best solution for handling dead animals because it is effective and cost-efficient, Augustin says. Composting carcasses is a simple process that, through time, changes the animal to a soil-like product.
However, the composting pile needs to be managed properly. You need a bulking material high in carbon, such as wood chips or straw. Place about two feet of the bulking material in an area that drains well, but where runoff will not reach waters such as rivers, lakes or streams. Place the carcass on the bulking material and add another two feet of bulking material on top of the carcass. The animal will undergo thermophylic decomposition.
During this period, temperatures in the pile range from 120 to 160 F as bacteria feed on the animal and bulking material. Temperatures should be monitored with a probe-type thermometer.
The pile also requires adequate moisture and oxygen. The pile should have about 60 percent of the pores filled with water and the remaining pores filled with air. The bulking material helps the pile maintain oxygen.
After about 90 days, the pile should be turned with a front-end loader to incorporate more oxygen. More bulking material and water may need to be added at this time. You should continue to monitor the pile’s temperature. When the temperature falls below 120 F, the pile should be turned again. After about six months, and three to five turns, the carcass should be entirely composted.
The benefits of composting include reducing the amount animal carcasses, destroying pathogens and eliminating odor. Also, pests tend to stay away from the pile.
“The finished product is an odor-free, soillike fertilizer that adds a little value to a dead animal,” Augustin says.
Information on soil types for selecting suitable disposal sites can be found in each county’s soil survey or online at http://websoilsurvey.nrcs.usda.gov.
Producers’ eligibility for Federal Emergency Management Agency assistance for catastrophic losses may depend on showing that livestock were disposed of appropriately, Rockeman says. Producers experiencing catastrophic livestock losses should consult the state department of health’s guide 14 on emergency waste disposal variances. The guide is available at http://www.ndhealth.gov/flood.