Effects of Aeration Pattern in Force-Aerated Static Pile Composting Methods for Rose Oil Processing Solid Wastes

Three trapezoidal piles of the mixtures consisting of rose oil processing solid wastes, separated dairy and poultry manure, and straw as bulking agents were composted to determine the effects of aeration pattern employing forced aeration on various physical and chemical properties and energy consumption by aeration. Temperature feedback control of aeration fans was performed with Rutgers strategies in the positive mode. Aeration patterns with on/off cycles (minute/minute) of 5/30, 7.5/30, and 12.5/30 were performed for Pile-1, Pile-2, and Pile 3, respectively. The control group was set to 5/30 (on/off time) and the experimental groups were set to 7.5/30 and 12.5/30 (on/off time). The results showed that although composting performance parameters of temperature and O2 as a function of time showed some differences, the similar end-product quality in terms of pH, EC contents and total phosphorus was achieved. The highest energy consumed by fans per Organic Matter Loss (OML, %) of composting (1.044 kWh/OML) was obtained when the fan on/off cycles of 5/30 was applied. When the fan on-time increased to 12.5 min, the energy consumed by the fan was reduced by 12.55% (0.913 kWh/OML). It was concluded that operating the composting process at the higher fan on-time (Pile-3) within acceptable limits appears to be economically convenient in conjunction with energy consumption by aeration fans.