This experimental work aims to prove the faisability of anaerobic fermentation of different organic susbtrates in an anaerobic digester and to test the influence major running parameters (solid retention time, temperature, biochemical composition of substrates, innoculum). Anaerobic fermentation of different organic substrates was performed continuously by use a twenty liters laboratory high-solids digester. Methane yields, productivities (now rate, CH4 and CO2 concentrations....), fermentation parameters (pH, buffer capacity, volatile fatty acid,...) as well as chemical composition of organic substrates and digester fluids were analysed during 12 months. The experiment was achieved for three different mixtures : firstly a mix of organic fraction of municipal solid wastes, pig slurry and clover; secondly a mix of organix fraction of MSW, pig slurry and wheat and thirly a mix of organic fraction of MSW, cow slurry and ensiled maize. The influence of the temperature (mesophilic and thermophilic) and also the retention time, were performed on this lastest organic mixture. At load of 8.5 kg VS.m(-3).day(-1) and retention time of 15 days, methane yields were 168 to 193 litres(kg VS)(-1) and productivities 2.02 to 2.69 m(3) CH4.m(-3).day(-1). The methane concentration was on average 57% in biogas during the seven months of experimentation. The introducing of a crop into the digester slowed an increase of methane yield and productivity. During the steady-state of anaerobic fermentation the physical and chemical conditions in digester were particulary stable : none storage of volatile fatty acid (VFA) or hydrogene (H-2) or ammonium (NH4+), stability of pH, high buffer capacity,... Those conditions are very important for the management of an industrial anaerobic digester. The influence of hydraulic retention time seems to be not very important to increase biogas yields. At a HRT of 18 days, the biodegradation of organic matter is optimal regarding microbial kinetics and impacts on the size of an industrial anaerobic digestion plant. The results concerning the impact of fermentation temperature show that at termophilic temperature the anaerobic fermentation is more effective. This study presents results of experimental investigations into using agricultural biomass (crops, animal faeces:...) with organic fraction of municipal waste for waste treatment and for methane production. Those results have proved that it's possible to process in a same anaerobic digester different organic wastes and substrates. This concept could be an interesting solution to solve a territorial problematic of organic matter treatment by using biomass co-digestion.
