Optimisation of biodegradation conditions for the treatment of olive mill wastewater

International audienceThe aim of the present paper was to optimise the conditions of aerobic treatment of olive mill wastewater. To do so, the waste was treated following the experimental optimal design methodology studying the set of factors susceptible to influence the treatment (pH, C/N ratio, aeration and temperature). The results of a first series of experiments showed a strong correlation between the reduction in the levels of polyphenols and three of the parameters studied, i.e. the C/N ratio, aeration and temperature. Optimised conditions led to a 94% drop in polyphenols. Then, for a finer study of the conditions, just two parameters were varied, the pH and the C/N ratio. The results showed that the conditions of pH modification (addition of lime or sodium hydroxide) and the C/N ratio (urea or ammonium nitrate) allowed the micro-biological activity to be very significantly improved. This led to polyphenol reductions of 51% and 76%

Effet de la préparation de déchets ménagers sur leur potentiel et leur cinétique méthanogène

International audienceThe goal of this study is to evaluate the impact of different Municipal Solid Waste preparation methods on the anaerobic digestion kinetics and yield. Reconstituted MSW samples were thus incubated under batch anaerobic conditions, with or without inoculation. Preparation methods include aerobic, thermal and acid preparations. Incubation data were compared by fitting to a modified Gompertz equation in order to determine characteristic parameters such as latency time before the onset of methanogenesis, maximum methane production rate and total methane production. The results indicate that inoculation of MSW is necessary not only to decrease the latency before the onset of methanogenesis, but also to increase the overall conversion yield of organic carbon to methane. Results also suggest that soaking under acidic conditions is an efficient way of waste preparation to enhance methanization