Determination of effects of temperature on composting of three phase olive oil processing solid waste with poultry manure and sawdust

In this study, three phase olive oil processing solid waste with poultry manure and sawdust with the proportion of 60.22%, 14.60% and 25.18% on dry weight basis was composted. The initial carbon/nitrogen ratio of the mixture was 23.59 and the initial moisture content was 53.46% (wet basis). In the experiment, fourteen 100 liter automatically controlled compost reactors were used. Control of compost temperatures was performed according to Rutgers ventilation strategy. Composting was carried out at 40, 45, 50, 55, 60 and 65 at 70 C control temperature (Tsp) to determine the effect of different composting temperatures on composting of three phase olive oil processing solid waste with poultry manure and sawdust. Each control temperature was run with two replications. Trials lasted 26.83 days. During the experiments, temperature, air flow rate, electricity consumption of ventilation fans and ammonia concentration were measured. In the experiment, compost moisture, organic matter, pH, electrical conductivity, NH4+−N, NO3−−N, carbon and nitrogen were measured. Dry matter loss (KMK), organic matter loss (OMK) and nitrogen loss (AK) were determined. The optimum temperature range of composting process has been tried to be determined based on KMK, OMK, AK, electricity consumption by ventilation, and ammonia losses. The results of the study showed that compost temperatures reached Tsp temperatures within the first 6 days for all the reactors. At low Tsp temperatures, the control of the compost temperature became more difficult and the control point exceeded. Higher air flow were applied to control the ventilation fans when the Tsp value was 40 C. As the Tsp value increased, the air flow rate values decreased. Since the thermophilic temperatures were dominant in high Tsp values, it was easier to control the ventilation fans at these temperature levels. KMK and OMK increased as Tsp increased. The AK took the maximum value when the Tsp value was 65 C. Energy consumption E() values of fans from ventilation were investigated. As Tsp increased, E()/KMK and E()/OMK decreased based on decreasing exponential function. On the other hand, although there was no significant change in cumulative ammonia emission (ENH3-N) up to 65 °C, ENH3-N increased exponentially at higher temperatures. Consequently, when ENH3-N, E()/KMK, E()/OMK and AK were evaluated together, composting should be performed at temperatures lower than 65 °C for composting system operation. ENH3-N and AK reducing the quality of the final compost are required to take into account to reduce operating costs. For this reason, the optimization among E()/KMK, E()/OMK, ENH3-N and AK is required.