Performance of thermophilic semi-dry anaerobic digestion process changing the feed biodegradability

The study concerns the application of the semi-dry single phase thermophili c anaerobic digestion process to the organic fraction of municipal solid wa ste. The experiments were carried out using 3 m(3) and 1 m3 CSTR pilot scal e reactors. The process performance in terms of biogas yields, digester sta bility and kinetic aspects was studied, considering a progressive increase in the feed biodegradability, in order to evaluate the process behaviour ch anging from an undifferentiated collection of waste to a separate collectio n. This was carried out using blends of two different kinds of substrates: mechanically sorted organic fraction of municipal solid wastes (MS-OFMSW) a nd source sorted organic fraction of municipal solid wastes (SS-OFMSW). The study shows that OLR up to 6 kgTVS/m(3)d can be applicable for the medium selected fraction (TVS/TS less than or equal to 0.7), while for the MS-OFMS W alone this limit can be doubled. The results obtained with SS-OFMSW alone suggest the use of the double phase process to give more stable conditions .