Development of a Dynamic Model for Predicting Humic and Fulvic Acids Production in a Composting Process Using Olive Mill Wastes

In this work, a dynamic mathematical model for the prediction of fulvic (FA, g/kg) and humic acids (HA, g/kg) production during the humification stage of an olive mill waste residues (OMWR) composting process was developed. The dynamic modeling technique was applied successfully to the data record from an industrial composting process using OMWR as organic substrate collected from different III-phase olive mills. The applied prediction technique was based on time series theory and on regression analysis by residuals. The effect of pH, of Water Holding Capacity (WHC, %), of Electrical Conductivity (EC, mS/cm) and of ammonium nitrogen concertation (N-NH4, g/kg of TS) on FA and HA production was examined using daily measurements of all the above parameters for the last sixty days of the composting period. The experimental results show a strong reverse interrelation between FA and HA verifying that the HA production is based on FA reduction. The adequacy of the created dynamic models was checked by the x2 test giving reliable result.Foragers and Food Production in Africa: A Cross-Cultural and Analytical Perspective. Paper for the 48th annual Society for Cross-Cultural Research (SCCR) meetings, Jacksonville, Florida, February 13-16, 2019.

Keywords: Humic acids; Fulvic acids; Composting; Humification; Dynamic model; Olive mill waste residues (OMWR)