Process Biochemistry 28 (1993) 397-404 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Kinetic Study of Anaerobic Digestion of Olive Mill Wastewater Previously Fermented with zyxwvutsrqponmlkjihgfedcbaZYXW Aspergillus terreus R. Borja Instituto de la Grass y sus Derivados (CSIC), Avda. Padre Garcia Tejero 4, E-4 10 12 Sevilla, Spain S. E. Garrido, L. Martinez Departamento de Ingenieria Quimica, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, E-18071 Granada, Spain A. Ramos-Cormenzana Departamento de Microbiologia, Facultad de Farmacia, Unversidad de Granada, Campus Universitario de la Cartuja s/n, E- 1807 1 Granada, Spain & A . M artin Departamento de lngenieria Quimica, Facultad de Ciencias, Universidad de Cbrdoba, Avda. San Albert0 Magno s/n, E-14004 Cbrdoba, Spain (Received 12 August 1992; revised version received and accepted 3 October 1992) A kinetic study has been made of the anaerobic digestion of olive mill wastewater previously fermented with Aspergillus terreus. The anaerobic process was carried out in a digester containing Sepiolite as support for the mediating bacteria. The anaerobic digestion process was found to follow first-order kinetics and the experimental methane volume (G) - time (t) data to conform to an equation of the form G = G ,n [I -exp (- K, t)/, fy om which the apparent kinetic constant, K,. was calculated. The kinetic constant was found to be scarcely influenced by the substrate concentration over the studied COD (chemical oxygen demand) range (viz_. 3=9-8.8gllitre). Its mean value was I.45 days I. This value was substantially higher than that obtained in the anaerobic digestion of untreated olive mill wastewater, and the process seemingly involved no inhibition phenomena as the biotoxicity and the totalphenolic compound content (analysed by high pelfvrmance liquid chromatography HPLC) were reduced by 86-8 and 94.3% respectively as a result of the pretreatment. Finally, the average zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIH COD @action removal was around 70% and the yield coefficient was 349 ml CH, STP/g COD, viz_. 30% higher than zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA that provided by untreated wastewater. Corresponding author: A. Martin. 397 Process Biochemistry 032-9592/93/$6.00 Q 1993 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Else&r Science Publishers L&J, Engla&.