[ Objective | Process | Design | Starting the Compost ]
Each year over 7 million kg of mortality has to be disposed of on Alberta chicken and turkey farms. Alternatives to the unsitely, smelly, unsanitary, and potentially ground water contaminating open pit methods of disposing of these carcasses have to be found. There are several alternatives. These alternatives should be economical and environmentally and biologically sound. They include:
AAFRD's Poultry Team has recognized that waste management (mortality disposal) is an important issue. Since many of our larger poultry operations are located near large population centres, odour production and flies inevitably cause problems for adjacent neighbours. A composting project would certainly be appreciated, not only by these neighbours, but also by municipal and health officials. Furthermore, the range of disposal alternatives that will be acceptable in the future is almost certain to be limited and expensive. After careful consideration of all of the above alternatives, the Team decided to pursue the composting idea. Mortality composting is a two stage natural process in which beneficial bacteria reduce and transform the carcasses into a useful compost. The process has proven to be very successful in other geographical areas, but to our knowledge, no one has demonstrated that mortality composting is a practical management alternative for commercial operations under Alberta conditions. Aware of this, the Poultry Team has partnered with the federally/provincially funded Canada Agriculture Environmental Sustainability Agreement (CAESA), the MD of Foothills Agriculture Service Board, and Reg Ference, a broiler producer, to build a demonstration facility at the Ference farm in Black Diamond. Input and guidance was also received from the University of Alberta, Olds College, the Foothills Health Unit, and the Town of Black Diamond. Underlying the entire project was the fact that it was going to be carried out on an actual commercial operation, using regular farm labour and equipment. Some of the parameters that will be measured and looked at include:
The overall plan for the project was taken from the work of Dr. Dennis Murphy, University of Maryland. Dr. Murphy is affectionately known as the "father of poultry mortality composting." His initial work dates back to 1988. The concept of composting mortality relatively new here in Alberta and many people are not familiar with it. A great deal of "educating" had to be done when we were applying for the necessary permits from the local municipal authorities. Certain perceptions that some people had about the process had to be changed! We felt it was extremely important that everyone impacted by the trial be fully informed of just what is involved, how the process works, and to address any concerns these individuals may have. Eventually, the necessary paperwork, permits, etc. fell into place.
The next step was the actual construction of the building. The size of the composter is based on the farm capacity, bird size at the end of the cycle, and average mortality. The following simple formula was used to size the composting facility:
Table 1. Number of First-Stage Composter Bins Required Based on Farm Capacity (4.2 lb. Bird)
| Farm Capacity | Required Cubic Feet For First Stage Bins |
Number of First Stage Bins (5'x5'x8') |
Require Cubic Feet for Secondary Stage Bins |
|---|---|---|---|
| 20,000 | 210 | 1 | 210 |
| 40,000 | 420 | 2 | 420 |
| 60,000 | 630 | 3 | 630 |
| 80,000 | 840 | 4 | 840 |
| 100,000 | 1050 | 5 | 1050 |
| 120,000 | 1260 | 6 | 1260 |
We determined that an operation the size of Ferences (131,000 birds per cycle) required 1500 cubic feet primary bin space and a similar amount of secondary bin space. The bins were to be housed in a 32' X 40' building. In order to take advantage of the winter sun, the 5 primary bins are located on the south side of the structure. The bins were sized to accommodate the Bobcat used on the farm. The building sits on a concrete pad that slopes to the middle to prevent and possible leachate from escaping. All of the wood used was pressure treated and the building is enclosed on 3 sides with the south side remaining open. All openings were screened off to prevent wild birds from entering. We felt it was important to have a roof in order to control the moisture content of the compost.
Again, using Dr. Murphy's work, the following recipe was to be used:
Table2. Formula for Mortality Composting
| Materials | Parts By Weight |
|---|---|
| Dead chickens | 1 |
| Chicken Manure | 2 to 3 |
| Straw (wheat) | 1/10 |
| Water (add sparingly) | 0 to 0.5 |
The formula is designed to produce a product in the primary bin that has a moisture content of 40-60% and a carbon:nitrogen ratio of between 15 and 30:1.
The primary bin content is made up of alternating layers of litter, straw and dead birds. An initial double layer of litter (not cage layer droppings!) is put on the bottom. Next, a layer of straw, then birds, water and then litter, but this time only a single layer. The process is repeated until the bin is full. The final layer or cap is made up of 2 layers of litter. Birds are not to be placed withing 6 inches of the perimeter walls, otherwise thermophilic temperatures are not reached and fly breeding will take place.
Monitoring of pile temperatures is critical. Under temperate climatic conditions, peak temperatures of 55-60°C will be reached after 7 to 14 days. Because the composting process in aerobic, a drop in temperature signals that microbial action has caused the O2 to decrease, slowing down the activity and it is time to aerate the pile by moving it to the secondary bin. It is important when transferring the compost to dump the material from as great a height as possible. This increases both porosity and aeration of the material. Once the compost has all be placed in the secondary area, the pile should be capped with dry litter or fully mature compost in order to prevent flies from breeding. Just as in the primary bin, internal temperatures will begin to rise in a few days. Routine aeration of the material in the secondary bins will speed up the process but isn't necessary. We expect the material can be moved to a stockpile in 3 to 4 weeks with the entire process taking 6 to 8 weeks. However, the compost still is not mature at this point and requires further aging before it can be spread. The stock pile does not need to be covered. Mature compost should have the consistency of a peat moss/soil type of mixture and be free of any obnoxious odours.
Water should be added sparingly. Too much will reduce the porosity of the mixture and displace the 02. Follow the recommended recipe. We felt that we were adding too much straw and cut back from the recommended amount, probably by up to one half. Again, this reduced the porosity and lead to anaerobic decomposition, yielding a very offensive smelling compost. The straw should be cut into fairly short pieces in order to increase porosity. Be careful how many layers are built. The weight of to many layers can lead to compaction of the lower layers. This forces out moisture and O2. Do not use immature compost or wet litter to cap the piles. This leads to huge fly/maggot populations. The recipe we were following called for the first layer to be a double layer of litter. We are going to try changing that to a double layer of straw. Again, this should increase the porosity. The literature that we have been reading that has come out of the US has indicated that the compost should be ready for spreading in the fields in 6 to 8 weeks. We don't feel the material that is coming from our project is near ready by this time. We have not yet been able to define what mature compost is. It is taking about 30 minutes per day to operate the composter.
So far the composting project has proven to be an excellent alternative to the more conventional methods of mortality disposal. We are still on a very steep learning curve but so far the project has met our expectations. We have received inquiries from producers as well as various levels of government, including municipal, health, and environment. Some governments have imposed very strict regulations pertaining to intensive livestock and poultry production. The State of Alabama, for example, requires that every person that grows, feed, or otherwise produces poultry for commercial purposes, and every person who operates a commercial poultry hatchery for the production of baby chicks and turkey poults, to have equipment with adequate facilities for the handling, destruction, and disposal of all dead poultry, poultry carcasses, unhatched and unused eggs and other poultry waste. The government prescribes size, type and dimensions for pits. It also requires and prescribes chemical of disinfectant treatments to be applied. They approve the use of incinerators or other burning methods and any other recommended methods or facilities for the handling, destruction, and disposal of dead poultry, poultry carcasses, unhatched or unused eggs, and other poultry waste. These facilities must be kept and maintained by every commercial grower and every hatchery in Alabama. The handling, destruction and disposal of dead poultry, poultry carcasses, unhatched or unused eggs and other poultry waste shall be performed by the use of the required facilities in a manner prescribed by the government. These regulations are enforced with the government given the authority to quarantine and prohibit the removal or other disposition of any poultry and eggs from premised, buildings, and vehicles or other places unless such poultry and eggs are produced on premises equipped with approved disposal facilities. Alabama was able to recognize composting as an accepted method of dead bird disposal without additional legislation. However, composters must be built according to specifications.
We believe we are some time away from this type of legislation, simply by virtue of our size. We do nonetheless, have to be proactive. The commercial poultry industry is headed in the direction of having fairly strict rules imposed on it that pertain to carcass disposal. There is no doubt in my mind that composting will be looked upon as one of the approved methods. Composting doesn't get rid of mortalities, the process transforms the mortalities into amenable material that lead to a safe final disposal.