Moisture affects the physical and biological properties of compost and other solid-state fermentation matrices. Aerobic microbial systems
experience different respiration rates (oxygen uptake and CO2 evolution) as a function of moisture content and material type. In this
study the microbial respiration rates of 12 mortality composting envelope materials were measured by a pressure sensor method at six
different moisture levels. A wide range of respiration (1.6–94.2 mg O2/g VS-day) rates were observed for different materials, with alfalfa
hay, silage, oat straw, and turkey litter having the highest values. These four envelope materials may be particularly suitable for improving
internal temperature and pathogen destruction rates for disease-related mortality composting. Optimum moisture content was determined
based on measurements across a range that spans the maximum respiration rate. The optimum moisture content of each material
was observed near water holding capacity, which ranged from near 60% to over 80% on a wet basis for all materials except a highly
stabilized soil compost blend (optimum around 25% w.b.). The implications of the results for moisture management and process control
strategies during mortality composting are discussed.
Published by Elsevier Ltd.