title: Characterization of olive mill wastes composts and their humic acids: stability assessment within different particle size fractions.
abstract: Compost stability assessment within different particle size fractions was studied. Humic acids (HAs) were extracted from two kinds of co-composts prepared using evaporated olive mill wastewater (OMSW) or solid waste from olive oil extraction (OC) and poultry manure (PM). The elemental composition, Fourier-transform infrared spectroscopy (FTIR) and 13C-NMR (nuclear magnetic resonance) analysis and molecular weight distribution were investigated to assess the composted organic matter stability in different fractions. In both composts, organic matter content was higher in the > 2 mm fractions than in the < 2 mm fractions, because of fractions' richness in hardly biodegradable compounds. Spectroscopic analysis revealed that OMSW compost fraction < 2 mm and OC compost 2-4 mm fraction were rich in aromatic compounds and oxygenated groups but poor in aliphatic structure. Moreover, the HA distribution reflected a high stabilized compost < 2 mm fraction, especially from evaporated effluent known as phytotoxic. However, the 4-6 mm fraction included high aliphatic compounds besides aromatic structures and did not exhibit any phytotoxicity, confirming compost fraction maturity. However, the low C/N ratio, the high OMSW compost mineral nutritive elements and the high aromatic C rate reflected highly stabilized products. Consequently, the performance of both prepared organic fertilizers for agriculture use contested the previous negative effect ascribed to olive mill wastewater.
authors.affiliation: UR 'Etude et Gestion des Environnements Urbain et Côtier, LARSEN', University of Sfax, National Engineering School of Sfax, Sfax, Tunisia.
authors.forename: Saoussan
authors.initials: S
authors.lastname: Masmoudi
authors.forename: Raja
authors.initials: R
authors.lastname: Jarboui
authors.forename: Hafedh
authors.initials: H
authors.lastname: El Feki
authors.forename: Teresa
authors.initials: T
authors.lastname: Gea
authors.forename: Khaled
authors.initials: K
authors.lastname: Medhioub
authors.forename: Emna
authors.initials: E
authors.lastname: Ammar
mesh_terms: D005525:Food-Processing Industry; D006812:Humic Substances / Q000032:analysis*; D007220:Industrial Waste; D031658:Olea / Q000737:chemistry*; D010316:Particle Size; D012987:Soil / Q000737:chemistry*
chemical_list: D006812:Humic Substances; D007220:Industrial Waste; D012987:Soil