Tile macroenergetic parameters of the anaerobic digestion of black-olive wastewater, i.e. the yield coefficient for the biomass (Y, g VSS/g COD) and the specific rate of substrate uptake For cell maintenance (m, g COD/g VSS.day) decreased 6 times and increased 5 times. respectively, when the influent substrate concentration increased from 1.1 to 4.4 g COD/l. This was significant at 95% confidence level. The use of the Guiot kinetic model allows a more accurate prediction of growth yield to be made as it relates substrate utilization to product formation.