Effect of compost bed size on the degradation of organic matter in co-composting of horse stable waste and vegetable scraps

Abstract

Composting is an approach to convert residual waste typically organic waste into a soil amendment that beneficial to increase the nutrient content within. This study was carried out to integrate different size of co-composting of horse stable waste and vegetable scraps. The composting process was conducted for 15 days. Compost bed size of 3 kg, 6 kg and 9 kg were degraded in three compost bed with the same dimension and size. Moisture content was fixed at 50 %, particle size was fixed at 20 mm while C/N ratio for compost material was fixed at 28:1. Parameters such temperature, moisture content, porosity, pH, C/N ratio and total organic carbon were analysed to evaluate the effect of co-composting on different compost bed size. Compost is necessary to achieve thermophilic phase (> 40 ºC) for three days. This is necessary to kill pathogens and plant weeds that present in the compost. Moisture content decreased significantly over time. Initially, moisture content was fixed at 50 %, as the composting process continues over 15 days, moisture content for compost bed 3 kg, 6 kg and 9 kg drop to 27.23 %, 31.55 % and 40.73 % respectively. During the first week of composting, pH value for different compost bed was fluctuate resulted from decomposition of organic materials.