title: Maturity assessment of composted olive mill wastes using UV spectra and humification parameters.
abstract: In this study, two olive mill wastes - exhausted olive cake (EOC) and paste of olive mill wastewater naturally dehydrated (POMW) - were co-composted and mixed with 25% sesame bark (SB). The humification process was evidenced by quantifying the humic substances and the generally accepted humification indices: (i) the ratio of humic acid (HA) carbon to fulvic acid (FA) carbon (CHA/CFA), (ii) the ratio of water soluble organic carbon (CW) to total organic nitrogen (Cw/Norg), (iii) and the ratio of humic acid carbon to total organic carbon CHA/Corg and by determining the absorbance ratios: E2/E4, E2/E6 and E4/E6. The results showed that the time required to reach maturity was dependant on the chemical properties of the initial raw materials used. The compost including EOC had more nitrogen and synthesised more polymerised HA, the POMW compost also had acceptable degrees of stability and maturity at the end of the process. Maturation was confirmed by a decline in Cw below 1.7, an increase in nitrogen, in HA, in CHA/CFA and an elimination of phytotoxicity. Composts produced with olive mill wastes, experimented on potato culture in the field, can be considered beneficial to soils because of their humification indexes and no toxicity.
authors.affiliation: Ecole Nationale d'Ingénieurs de Sfax, B.P. "W", 3038 Sfax - Tunisie, UR Etude et Gestion des Environnements Urbains et Côtiers, Larsen, Tunisia.
authors.forename: Fatma
authors.initials: F
authors.lastname: Sellami
authors.forename: Salma
authors.initials: S
authors.lastname: Hachicha
authors.forename: Mohamed
authors.initials: M
authors.lastname: Chtourou
authors.forename: Khaled
authors.initials: K
authors.lastname: Medhioub
authors.forename: Emna
authors.initials: E
authors.lastname: Ammar
mesh_terms: D019649:Food Industry; D006812:Humic Substances; D007220:Industrial Waste; D031658:Olea; D012037:Refuse Disposal / Q000379:methods*; D012987:Soil; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
chemical_list: D006812:Humic Substances; D007220:Industrial Waste; D012987:Soil