Effect of Wood shavings on the Temperature Profile of Livestock Waste during Composting with Daily Turning

Abstract

Measurements were conducted to assess the impact of wood shavings on the temperature profiles of cattle and pig manure during aerated composting. Cattle stomach waste to wood shavings were mixed in mass ratios of 100:0%, 80:25%, and 75:25% and placed in three different chambers. Pig manure was also mixed with wood shavings in ratios similar to that of cattle stomach waste and placed in three different chambers. The piles were left to compost for 21 days after which the experiment was repeated. During composting, each pile temperature and pH were measured daily. On each measurement day, the compost pile in each chamber was weighed and aerated by moving into an empty chamber. Compost samples were collected from each chamber twice a week for dry matter and volatile solid contents analyses. Results showed that composting pile temperatures increased with increasing levels of wood shavings added to manure. Pile temperature profiles followed a three-stage configuration; mesophilic, thermophilic, and a further mesophilic stage. The duration of each stage depended on the type of livestock manure and the quantity of wood shavings used for amendment. The duration of the thermophilic stage for composting piles amended with wood shavings more than doubled that of piles not amended with wood shavings. Aerated composting of livestock manure significantly reduced the mass with a greater reduction favoured for manure amended with wood shavings. There was no clear trend in pile volatile solid contents during composting. The pH profiles indicated an increasing trend throughout the composting duration.