ABSTRACT
The main objective of this study was to evaluate the potential of organic waste streams for composting. For that purpose, different blends were used, with prevalence of waste-water treatment sludge, considering: 30 or 50% sludge and 50 or 70% of other wastes such as corn silage, expired animal feed and biomass ash. Composting in turned piles of around 1 m3 was performed. The process was monitored during 73 days. The obtained product was analyzed regarding physical, chemical, microbiological and phytotoxicity parameters. The best results were obtained using 50% sludge, 30% of wood chips, 5% of ash, 5% of animal feed and 10% of corn silage; however, high losses of heat occurred, hygienization temperatures were not reached and thus microbiological parameters weren’t fulfilled. A class II type of material (Decree-Law No. 103/2015 on fertilizing materials) is expected to be obtained at a higher scale.
