ATA Corp. is an Aiken-based chemical engineering firm utilizing technologies that are capable of providing waste reduction and recycling options for municipal and industrial solid waste and/or wastewater problems. Technology examples include:

1. Browns of Carolina, LLC.
2. Prestage Farms, Inc.
3. Southeast Paper Co.
4. International Paper
5. Riley Stoker Corp.

Disposal of animal mortality is an issue that is becoming a very large problem for these industries. This is primarily due to the fact that very few acceptable, cost-effective options exist. Carcass disposal via burial is rapidly disappearing as an option in most states. Incineration is another option, but incinerators have a relatively short life cycle (typically three years), have odor problems, and leave the grower with nothing of value after disposal. Composting is an option, but has not gained widespread acceptance for stabilizing animal mortality due to the negative aspects of static pile and/or windrow techniques.

ATA Corp. recently procured a rotary in-vessel composting system (shown below in Figure 1) to assist the Swine and Poultry industries in the Carolinas and Georgia with their waste problems. This system can be utilized to process a wide variety of solid wastes. For example, the rotary composter has been successfully demonstrated on animal manures and mortality, institution food wastes, poultry hatchery wastes, and pulp and paper sludge. Eleven commercial units are presently in use across the country stabilizing various animal and institution wastes, producing valuable composts. The composted products can be used as soil amendments, or in certain cases have significant value as cattle feed supplements.

A demonstration-sized unit was procured from the manufacturer in Texas. This unit is capable of producing roughly 1 yard/day of finished material. The composter consists of an insulated drum that continuously. The unit is fed a mixture of animal mortality and manure with bulking agents (e.g., wood shavings), and thermophilic bacterial action breaks down the manure and carcass. The unit is sized to compost ~250-300 lb./day of mortality mixed in with ~300-400 lb. of manure/bulking agent mix. While the unit is being referred to as a demonstration unit, this system could be a full-size unit for smaller farming operations. Systems can be obtained through ATA Corp. that can process upwards of 6,000 lb./day of animal mortality.

This report will summarize a composting demonstration conducted on whole hogs, using turkey litter as the nitrogen and bulking source.

Summary of Hogs and Litter Composting Demonstration

The unit was loaded with three large sows (120 lb., 170 lb., 200 lb.), along with six small pigs with a group weight of 60 lb., for a total of ~550 lb. A manure/bulking agent mixture with a total weight of ~1,735 lb. was added to the composter that consisted of:

1. 655 lb. of aged turkey litter (tilled after three flocks, very broken down in appearance;
2. 195 lb. of separated cow manure solids (added for shavings content);
3. 85 lb. of wood shavings (for bulking agent);
4. 250 lb. of water (to increase water content to ~40%)

The hogs that were used had been dead ~36 hours, and were beginning to emit significant odor. The litter used for the demonstration, along with the hogs, was obtained from DeHart Farms of Pomaria, SC. The litter came from a turkey grow-out house after three flocks; it had been tilled between flocks, and by the time it was obtained for this test resembled dried soil. However, the nitrogen odor in the litter indicated that the litter was still quite potent.

The litter and hogs were loaded into the unit, as shown in Figure 3. The composting mass began to cover the hog carcasses, as shown in Figure 4. The process began almost immediately, and the composting mass temperature had climbed from ~60° F to ~100° F after 19 hours. The temperature climbed to ~125° F by 38 hours, and reached its maximum value of 140° F by 55-60 hours. Figure 5, left frame, shows the condition of the 170-lb hog after 17 hours of composting; all of the hair had been rubbed off and the carcass was extremely discolored. The were openings in the hide by this point, and liquid was beginning to ooze through the openings. Figure 5, right frame, shows the same carcass at 64 hours after beginning the composting process. The compost mix was operating at ~140° F, and efforts to raise the head of the carcass for photographing resulted in the jaw bone being pulled completely off. In fact, the entire head and carcass was extremely mushy and could easily be torn. The smaller pigs that were each ~10 lb. or less were already broken down by this time. Figure 6 shows many free bones in the mixture after 81 hours of composting.

There were several clumps of flesh-covered bones throughout the mixture. The process was in the final stages by this point, with bacterial activity focused on the remaining small pieces of flesh scattered throughout the unit. However, overall the finished compost was a very rich looking material, as can be seen in Figure 7. Here again a grinder to prepare the feed components would eliminate any bones in the final mixture.
 
 
 
 

Moisture content within the composting mass is vitally important to the composting process, and should be monitored routinely. This is particularly true when composting whole hogs, as were used in this demonstration. Significant moisture release occurs while the carcasses are breaking down, and excessive moisture levels locally can greatly reduce composting effectiveness (as discussed earlier). Two methods could be employed to deal with the moisture release, periodic additions of dry litter or dry bulking agents, such as shredded hay.
 
 

The demonstration discussed in this brochure was extremely successful. We were able to demonstrate that whole mortality from swine operations could be converted from a waste problem to a potentially profitable commodity through in-vessel composting. The carcasses can be broken down rapidly and completely, except for the larger bones (that could easily be disposed of). It is extremely important to monitor the moisture of the compost mixture prior to starting and periodically during the process. Moisture spikes resulting from carcass decomposition could be controlled by periodically adding fresh, dry materials, such as litter or bulking agents (e.g., hay, wood shavings, etc.)
 
 

Thank you for taking the time to read our literature. ATA Corp. is committed to helping you reduce or eliminate your wastes. If any of these ideas hold interest for you, we would be glad to discuss them further. We can be reached at the above address and phone number. Once again thank you and we look forward to hearing from you!

Vice President, ATA Corp.