 |
Emergency Livestock Disposal Home
Project Executive Summary
Project in Detail
Draft Guidelines for Emergency Cattle
Mortality Composting
|
 |
RESEARCH METHODS
System Performance
The general performance of the emergency composting system is evaluated through internal temperature monitoring, observation of pile height, internal oxygen measurements, and by periodic excavation and photography of test units.
Internal Temperature and Oxygen Monitoring
Internal pile temperatures are monitored by individual thermocouples placed at 20 locations in each test unit. Fourteen of the temperature sensors (7 around each pair of carcasses) are located within three conceptual zones which include: the anaerobic "core" of the pile between the carcasses; near the "outer surface" of the carcasses, and in the "outer envelope" of the pile.
Six of the 20 thermocouples in each test unit are located in a bundle of tubes known as the "tube cluster." These sensors are mounted inside six individual tubes in the cluster at 40-cm intervals so that temperatures can be monitored at locations which are a known distance from the center and outer edges of the piles. Temperature measurements made in this way will be used to obtain a more detailed picture of temperature gradients between the surface and the core, and to characterize the relative ability of various emergency cover materials to retain heat.
Six oxygen monitoring tubes in the tube cluster terminate at the same location as the thermocouples, permitting measurement of internal oxygen concentrations at the same six locations where temperature data are collected.
The photograph below shows six new test units immediately following their construction on November 11, 2003. The gray tubes protruding from the test units were subsequently cut off at the surface of the piles before thermocouples were inserted inside them. Following insertion of the thermocouples, individual tubes and those in the tube cluster (center right) were capped and insulated to prevent entry of cold air.
Excavation
Carcass decomposition is evaluated by temporarily excavating and photographing a small portion of each test unit three to six months after construction, and at end of the test run when piles are torn apart and spread on cropland near the research site.
To avoid excessive disturbance of pile structure and microbial activity, individual test units are temporarily excavated (and re-covered) only once during a trial . To gain understanding of the general progress of decay over time, however, some test units have been opened in as little as 100 days after construction, while others have been examined 150 - 210 days following construction.
On completion of a seasonal trial, piles are completely excavated and loaded into a manure spreader for application on cropland near the research site. During excavation, carcass remains are photographed, and a composite sample of the compost material is collected and submitted for nutrient analysis.
|
 |
In Brief
System performance monitoring includes:
1. Monitoring of internal temperatures within three distinct zones in each test unit.
2. Monitoring of temperature and oxygen gradients between the surface and core of the test units.
3. Temporary excavation and photography of carcass remains to determine the time needed for complete carcass decay.
4. Photography of remains and sampling of compost for nutrient content on final excavation of all trials.
|
 |
