Abstract

The main impact of olive mill wastes stored in open reservoirs is the emanation of unpleasant odorous substances. This manuscript focuses on the study of Alperujo and Orujo, two wastes that behave as sediments when stored in open pools. The aim was to monitor the changes in then physical-chemical parameters (ash. humidity, phenols. pH, proteins, fibers, oils and fats) and microbial biodiversity (through Ilumina platform for bacteria and fungi) as well as to characterize the evolution of volatile organic compounds as a consequence of waste decomposition. Gaseous emissions were analyzed during six months using thermal desorption gas chromatography mass spectrometry. A statistical analysis was performed in order to measure the impact of ambient conditions in the most relevant physical-chemical parameters. During the first three mouths, a decrease in the concentrations of compounds responsible for the scent was recorded, while compounds responsible of unpleasant odors appeared after three months. The dynamics of these odor compounds was related to the degradation of organic matter, the increase of microorganism’s diversity and the influence of the environmental variables that directly impacted physical-chemical parameters as well as the concentrations of fats.